TAVI -Summary

SUMMARY AND RECOMMENDATIONS

• Aortic valve replacement is the mainstay of treatment of symptomatic aortic stenosis (AS). Aortic valve replacement offers substantial improvements in symptoms and life expectancy.

• TAVR has been developed as a treatment for patients with severe symptomatic AS with unacceptably high risk for surgical aortic valve replacement.
• In appropriately screened patients with inoperable severe symptomatic AS, TAVR provides better outcomes compared to medical therapy including percutaneous valvotomy.
• However, TAVR offered no survival benefit compared to standard therapy in patients with an STS score of ≥15 percent because of the high degree of comorbid conditions in these patients.
• In appropriately screened patients with severe symptomatic AS, TAVR and surgical aortic valve replacement are associated with similar rates of one-year survival. However, stroke or TIA and vascular complications are more frequent with TAVR, and major bleeding and atrial fibrillation are more common after surgical valve replacement.
• A multidisciplinary team approach is recommended in approaching high-risk patients with symptomatic AS.

expert consensus document on transcatheter aortic valve replacement
http://www.sciencedirect.com/science/article/pii/S0735109712000022

Comparison of three methods of assessing cardiovascular disability

Class	New York Heart Association functional classification[1]	Canadian Cardiovascular Society functional classification[2]	Specific activity scale[3]
I	Patients with cardiac disease but without resulting limitations of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, dyspnea, or anginal pain.	Ordinary physical activity, such as walking and climbing stairs, does not cause angina. Angina with strenuous or rapid prolonged exertion at work or recreation.	Patients can perform to completion any activity requiring ≥7 metabolic equivalents, eg, can carry 24 lb up eight steps; do outdoor work (shovel snow, spade soil); do recreational activities (skiing, basketball, squash, handball, jog/walk 5 mph).
II	Patients with cardiac disease resulting in slight limitation of physical activity. They are comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnea, or anginal pain.	Slight limitation of ordinary activity. Walking or climbing stairs rapidly, walking uphill, walking or stair climbing after meals, in cold, in wind, or when under emotional stress, or only during the few hours after awakening. Walking more than two blocks on the level and climbing more than one flight of ordinary stairs at a normal pace and in normal conditions.	Patients can perform to completion any activity requiring ≤5 metabolic equivalents, eg, have sexual intercourse without stopping, garden, rake, weed, roller skate, dance fox trot, walk at 4 mph on level ground, but cannot and do not perform to completion activities requiring ≥7 metabolic equivalents.
III	Patients with cardiac disease resulting in marked limitation of physical activity. They are comfortable at rest. Less than ordinary physical activity causes fatigue, palpitation, dyspnea, or anginal pain.	Marked limitation of ordinary physical activity. Walking one to two blocks on the level and climbing one flight in normal conditions.	Patients can perform to completion any activity requiring ≤2 metabolic equivalents, eg, shower without stopping, strip and make bed, clean windows, walk 2.5 mph, bowl, play golf, dress without stopping, but cannot and do not perform to completion any activities requiring >5 metabolic equivalents.
IV	Patient with cardiac disease resulting in inability to carry on any physical activity without discomfort. Symptoms of cardiac insufficiency or of the anginal syndrome may be present even at rest. If any physical activity is undertaken, discomfort is increased.	Inability to carry on any physical activity without discomfort - anginal syndrome may be present at rest.	Patients cannot or do not perform to completion activities requiring >2 metabolic equivalents. Cannot carry out activities listed above (Specific activity scale III).

References:

1. The Criteria Committee of the New York Heart Association. Nomenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels, 9th ed, Little, Brown & Co, Boston, 1994. p.253.
2. Lucien C. Grading of angina pectoris. Circulation 1976; 54:5223.
3. Goldman L, Hashimoto B, et al. Comparative reproducibility and validity of systems for assessing cardiovascular functional class: Advantages of a new specific activity scale. Circulation 1981; 64:1227.

TAVI -part 3

COMPLICATIONS — Complications of TAVR include shock and low cardiac output during and following deployment, annular rupture, vascular complications, heart block, paravalvular aortic regurgitation, and stroke.

 Shock and low cardiac output during or immediately following TAVR may be triggered by anesthesia, volume depletion, rapid pacing, ischemia, and interruption in cardiac output during valve implantation . Management includes support of systemic blood pressure, inotropic support as needed, ventilatory support with intra-aortic balloon pump support as needed. Elective cardiopulmonary bypass is an option for patients at severe risk for hemodynamic instability.

A rare cause of ischemia is coronary ostia occlusion, which may be treated by percutaneous coronary intervention or coronary artery bypass graft surgery. “Suicide” left ventricle is a rare complication in which left ventricular outflow tract or intracavitary obstruction is precipitated by volume depletion and/or positive inotropic agents and is treated by administration of volume and a beta adrenergic receptor blocking agent.

Aortic annular rupture is a rare life-threatening complication of TAVR . Risk factors include smaller annular size or sinotubular junction, bulky calcification, and aggressive balloon predilation. Management options range from emergent conversion to an open procedure with aortic root replacement to pericardial drainage and autotransfusion of small leaks to comfort care.

 Vascular complications are a frequent early complication of TAVR. For example, in cohort B of the PARTNER trial, vascular complications were significantly more common in the TAVR group than in the standard therapy (including percutaneous valvotomy) group (30.7 versus 5.0 percent)  and in cohort A, vascular complications were more common in the TAVR group than in the surgical group (17.0 versus 3.8 percent)

Risk factors for development of heart block with need for permanent pacemaker implantation include pre-existing right bundle branch block and use of a CoreValve (versus Sapien valve) . In patients receiving the Sapien valve, the risk of this complication (1.8 to 8.5 percent) is similar to that observed following balloon aortic valvotomy or surgical aortic valve replacement. For example, in cohort B of the PARTNER trial, the rate of new pacemaker requirement at 30 days was similar in the TAVR and standard therapy (including balloon valvotomy) groups (3.4 and 5.0 percent)  and in cohort A was also similar in the TAVR and surgical groups (3.8 versus 3.6) . The risk of requiring a permanent pacemaker is higher (ranging from 19.2 to 42.5 percent) in patients receiving the CoreValve 

Post-TAVR aortic regurgitation — Post-TAVR aortic regurgitation includes paravalvular and central (valvular) jets.

Paravalvular aortic regurgitation is common, occurring in about 85 percent immediately post-TAVR. It is caused by incomplete apposition of the prosthesis with the aortic annulus due to inadequate inflation of the prosthesis or calcific deposits that prevent proper valve seating. Causes of paravalvular aortic regurgitation include a heavily calcified annulus, an undersized prosthesis, and an inadequate balloon aortic valvuloplasty prior to deployment of a self-expanding valve,

Paravalvular regurgitation is associated with adverse outcomes. In patients undergoing TAVR in cohort A of the PARTNER trial, at least mild aortic regurgitation was present in about 40 percent of patients and moderate or severe paravalvular aortic regurgitation was identified in approximately 10 percent during follow-up to two years . The presence of more than trace aortic regurgitation was associated with increased risk of late mortality (hazard ratio 2.11; 95% CI, 1.43 to 3.10). However, it remains unclear if mild or moderate aortic regurgitation itself leads to adverse outcomes or whether this finding identifies a higher risk patient subgroup.

Central regurgitation may be caused by improper valve sizing or deployment . Minor valve displacement may resolve gentle probing of the leaflets but severe leaks are an indication for valve-in-valve deployment.

The reported 30-day risk of stroke following TAVR in observational studies and clinical trials is 2 to 5 percent . Observational data have shown similar rates of stroke following transfemoral and transapical TAVR .

Data from the randomized cohort A of the PARTNER trial showed that rates of strokes or transient ischemic attack were significantly higher after TAVR than after surgical AVR at 30 days (5.5 versus 2.4 percent) and at one year (8.7 versus 4.3 percent), and there was a borderline significant trend at two years (11.2 versus 6.5 percent, p = 0.05)
Subclinical brain injury may be substantially more frequent than stroke as suggested by the following studies:

• A diffusion-weighted magnetic resonance imaging (MRI) study that compared 32 patients who underwent TAVR to 21 historical controls treated with surgical aortic valve replacement . New clinically silent cerebral foci of restricted diffusion were significantly more frequent in patients who had undergone retrograde aortic valve implantation than in those who had undergone surgical aortic valve replacement (84 versus 48 percent).
• Similarly high rates of new cerebral ischemic lesions detected by diffusion-weighted MRI were found in a study comparing transfemoral versus transapical TAVR . Similar frequencies of new lesions were found in 19 of 29 (66 percent) patients in the transfemoral group and in 22 of 31 (71 percent) patients in the transapical group. Of note, the patients in the transapical group had a higher frequency of peripheral vascular disease than in the transfemoral group (45 versus 17 percent), although the frequency of aortic plaque ≥4 mm was similar (29 and 28 percent). Most patients (76 percent) with new lesions had multiple lesions (median 3, range 1 to 31). The lesions were largely clinically silent, though one patient in each group had a clinically-evident stroke within 24 hours after the procedure.

Further study is required to determine the clinical significance of these observations. Although most of the new lesions were clinically silent, there is concern that silent cerebral infarcts are associated with subtle cognitive change and with an increased risk of subsequent dementia.

POST-PROCEDURAL CARE

Patients receive intravenous heparin during valve implantation and chronic antithrombotic therapy after implantation. Following implantation of the SAPIEN valve, the following antithrombotic regimen is recommended: dual antiplatelet therapy (aspirin 75 or 100 mg daily plus clopidogrel 300 mg loading dose followed by 75 mg daily) for six months; and after six months, aspirin 75 to 100 mg/day for life.

 Catheter-based aortic valves (Medtronic CoreValve, Edwards SAPIEN valve) have CE mark approval in Europe for patients with high or prohibitive risk for surgical valve replacement. In the United States, the Food and Drug Administration approved the Edwards SAPIEN valve for transfemoral implantation in patients with severe symptomatic native AS who have been determined by a cardiac surgeon to be inoperable for surgical aortic valve replacement and in whom existing co-morbidities would not preclude clinical benefit from correction of the AS

SUMMARY AND RECOMMENDATIONS

• Aortic valve replacement is the mainstay of treatment of symptomatic aortic stenosis (AS). Aortic valve replacement offers substantial improvements in symptoms and life expectancy.
• TAVR has been developed as a treatment for patients with severe symptomatic AS with unacceptably high risk for surgical aortic valve replacement.
• In appropriately screened patients with inoperable severe symptomatic AS, TAVR provides better outcomes compared to medical therapy including percutaneous valvotomy.
• However, TAVR offered no survival benefit compared to standard therapy in patients with an STS score of ≥15 percent because of the high degree of comorbid conditions in these patients.
• In appropriately screened patients with severe symptomatic AS, TAVR and surgical aortic valve replacement are associated with similar rates of one-year survival. However, stroke or TIA and vascular complications are more frequent with TAVR, and major bleeding and atrial fibrillation are more common after surgical valve replacement.
• A multidisciplinary team approach is recommended in approaching high-risk patients with symptomatic AS.

expert consensus document on transcatheter aortic valve replacement
http://www.sciencedirect.com/science/article/pii/S0735109712000022

Comparison of three methods of assessing cardiovascular disability

Class	New York Heart Association functional classification[1]	Canadian Cardiovascular Society functional classification[2]	Specific activity scale[3]
I	Patients with cardiac disease but without resulting limitations of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, dyspnea, or anginal pain.	Ordinary physical activity, such as walking and climbing stairs, does not cause angina. Angina with strenuous or rapid prolonged exertion at work or recreation.	Patients can perform to completion any activity requiring ≥7 metabolic equivalents, eg, can carry 24 lb up eight steps; do outdoor work (shovel snow, spade soil); do recreational activities (skiing, basketball, squash, handball, jog/walk 5 mph).
II	Patients with cardiac disease resulting in slight limitation of physical activity. They are comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnea, or anginal pain.	Slight limitation of ordinary activity. Walking or climbing stairs rapidly, walking uphill, walking or stair climbing after meals, in cold, in wind, or when under emotional stress, or only during the few hours after awakening. Walking more than two blocks on the level and climbing more than one flight of ordinary stairs at a normal pace and in normal conditions.	Patients can perform to completion any activity requiring ≤5 metabolic equivalents, eg, have sexual intercourse without stopping, garden, rake, weed, roller skate, dance fox trot, walk at 4 mph on level ground, but cannot and do not perform to completion activities requiring ≥7 metabolic equivalents.
III	Patients with cardiac disease resulting in marked limitation of physical activity. They are comfortable at rest. Less than ordinary physical activity causes fatigue, palpitation, dyspnea, or anginal pain.	Marked limitation of ordinary physical activity. Walking one to two blocks on the level and climbing one flight in normal conditions.	Patients can perform to completion any activity requiring ≤2 metabolic equivalents, eg, shower without stopping, strip and make bed, clean windows, walk 2.5 mph, bowl, play golf, dress without stopping, but cannot and do not perform to completion any activities requiring >5 metabolic equivalents.
IV	Patient with cardiac disease resulting in inability to carry on any physical activity without discomfort. Symptoms of cardiac insufficiency or of the anginal syndrome may be present even at rest. If any physical activity is undertaken, discomfort is increased.	Inability to carry on any physical activity without discomfort - anginal syndrome may be present at rest.	Patients cannot or do not perform to completion activities requiring >2 metabolic equivalents. Cannot carry out activities listed above (Specific activity scale III).

References:

1. The Criteria Committee of the New York Heart Association. Nomenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels, 9th ed, Little, Brown & Co, Boston, 1994. p.253.
2. Lucien C. Grading of angina pectoris. Circulation 1976; 54:5223.
3. Goldman L, Hashimoto B, et al. Comparative reproducibility and validity of systems for assessing cardiovascular functional class: Advantages of a new specific activity scale. Circulation 1981; 64:1227

TAVI -part 2

Transcatheter aortic valve replacement (TAVR) techniques are rapidly evolving, and results of published trials suggest that TAVR is emerging as the standard of care in certain patient subsets, and a viable alternative to surgery in others.

Comparison to medical therapy in inoperable patients — Evidence of a benefit of TAVR compared to standard medical care was provided by the PARTNER multicenter trial (cohort B) [. The investigators randomly assigned 358 patients with aortic stenosis who were not considered surgical candidates to either standard therapy including balloon aortic valvotomy or TAVR with an Edwards SAPIEN valve via transfemoral approach. The two treatment groups were similar, although the logistic EuroSCORE was slightly lower in the TAVR group (mean 26.4 versus 30.4).

The following findings were noted:

• At one year, the mortality rate was reduced with TAVR compared to medical therapy including balloon aortic valvotomy (30.7 versus 50.7 percent). The rate of the composite end point of death or repeat hospitalization was also reduced with TAVR (42.5 versus 71.6 percent).
• At two years, the mortality rate was 43.4 percent with TAVR compared to 68 percent for medical therapy.
• Among survivors at one and two years, functional class was better with TAVR versus medical therapy (75 versus 42 percent in NYHA functional class I or II at one year).
• The stroke rate was significantly higher in the TAVR group than in the medical therapy group at 30 days (6.7 versus 1.7 percent) and at two years (13.8 versus 5.5 percent).
• In the medical therapy group, balloon aortic valvotomy was performed in 82.3 percent at one year and in 85.3 percent at two years. Moderate or severe transvalvular aortic regurgitation was observed in 16.9 percent at 30 days and 15.2 percent at one year.
• In the TAVR group, moderate or severe paravalvular aortic regurgitation was identified in 11.8 percent at 30 days and in 10.5 percent at one year. Moderate or severe transvalvular aortic regurgitation was observed in 1.3 percent at 30 days and 4.2 percent at one year.
• Of note, TAVR improved survival in patients with an STS score of <15 percent but not in those with an STS score ≥15 percent.

Comparison to surgical therapy — The 699 patients in cohort A of the PARTNER trial were randomly assigned to undergo either TAVR (by transfemoral or transapical approach) or surgical aortic valve replacement . The following findings were noted:

• Mortality rates in the TAVR and surgical group were similar at 30 days (3.4 and 6.5 percent, p = 0.07), one year (24.3 and 26.8 percent), and two years (33.9 and 35.0 percent).
• Combined strokes or transient ischemic attacks were more frequent after TAVR than after surgical aortic valve replacement at 30 days (5.5 versus 2.4 percent, p = 0.04) and at one year (8.7 versus 4.3 percent, p = 0.04) with a borderline significant difference at two years (11.2 versus 6.5 percent, p = 0.05).
• More patients undergoing TAVR reported symptom improvement at 30 days, but at one year symptom improvement was similar in the two groups.
• Differences in other 30-day adverse event rates were also observed:
• TAVR was associated with more frequent major vascular complications (11.0 versus 3.2 percent).

• Surgical aortic valve replacement was associated with more frequent major bleeding (19.5 versus 9.3 percent) and new-onset atrial fibrillation (16.0 versus 8.6 percent).

• Moderate or severe paravalvular aortic regurgitation was more frequent after TAVR than after surgery at 30 days, one and two years (6.9 versus 0.9 percent at two years). The presence of paravalvular aortic regurgitation was associated with increased late mortality as discussed below.

Observational data

Early outcomes

For retrograde approach — Early outcomes were reported following retrograde replacement of the Edwards SAPIEN valve between November 2007 and January 2009 in 463 patients (mean age 82 years) with high estimated surgical risk (mean logistic EuroSCORE 26)

The following findings were noted:

• Procedural success was 95 percent.
• Procedural outcomes included conversion to open aortic valve replacement surgery in 1.7 percent, valve-in-valve replacement (a SAPIEN valve placed within a SAPIEN valve) due to malposition or moderate/severe aortic regurgitation after placement of the first SAPIEN valve in 0.6 percent, greater than moderate (2+) aortic regurgitation in 1.6 percent, coronary obstruction in 0.7 percent, and transfusion was required in 9.9 percent.

Major complications at 30 days included death (6.3 percent), stroke (2.4 percent), renal failure requiring dialysis (1.3 percent), and heart block resulting in permanent pacemaker implantation (6.7 percent). Vascular complications included access-related complications (17.9 percent), aortic dissection (1.9 percent), and non-access-related complications (1.1 percent).

In an echocardiographic study of 88 patients undergoing retrograde Cribier-Edwards or Edwards SAPIEN valve implantation, the mean transaortic valve gradient fell from a preprocedure baseline of 39±14 mmHg to 9±3 mmHg one day after the procedure and was 11±4 two years later .

Similar results were found in a multicenter study of retrograde implantation of a self-expanding stent valve (CoreValve) in 646 patients (mean age 81) with a mean logistic EuroSCORE of 23 :

• Procedure success was 97 percent and the mean transaortic valve gradient decreased from 49 to 3 mmHg.
• Procedural outcomes included death in 1.5 percent, conversion to open aortic valve replacement surgery in 0.5 percent, and implantation of a second valve (including valve-in-valve) in 2.6 percent. Paravalvular regurgitation was common but usually mild and not more than moderate.

At 30 days, mortality was 8 percent, heart block was treated with permanent pacemaker implantation in 9.3 percent, myocardial infarction occurred in 0.6 percent, and stroke occurred in 1.9 percent.

For transapical approach — The following early outcomes were reported following transapical implantation of the Edwards SAPIEN valve in 575 patients (mean age 81 years) with logistic EuroSCORE of 29

The valve prosthesis was implanted successfully in 93 percent with a 3.5 percent rate of conversion to open surgery. The early incidence of greater than moderate (2+) aortic regurgitation was 2.3 percent.

• At 30 days, major complications included death (10.3 percent), stroke (2.6 percent), major vascular complication (2.4 percent), myocardial infarction (0.7 percent), need for dialysis (7.1 percent), pacemaker implantation (7.3 percent), and bleeding requiring reoperation (2.1 percent).
• Outcomes for 100 patients undergoing transapical aortic valve implantation (mean age 83, mean logistic EuroSCORE 29) were comparable to those for 100 propensity-matched controls undergoing conventional aortic valve replacement (mean age 82, mean EuroSCORE 30) . Transapical aortic valve implantation was successful in 97 patients, and three patients required conversion to open surgery. There were no strokes in the transapical group and two strokes in the conventional group. The mortality rates for the transapical and conventional surgery groups were similar: 10 and 15 percent at 30 days and 27 and 31 percent at one year.

In a Canadian multicenter study of 339 adults with severe AS and high surgical risk, the Edwards Sapien valve was implanted by either the retrograde transfemoral approach or the antegrade transapical approach. The procedural success rate was 93 percent. Mortality at 30 days was 10.4 percent (9.5 percent for transfemoral and 11.3 for transapical approach). At one year, mortality was 25 and 22 percent in those treated with the transfemoral versus transapical approach. Predictors of cumulative late mortality were sepsis, need for hemodynamic support, pulmonary hypertension, chronic obstructive pulmonary disease, and chronic kidney disease. Compared to the rest of the cohort, outcomes were no different in adults with a heavily calcified proximal aorta (porcelain aorta) and those with frailty, conditions that were postulated to indicate higher risk .

A valve-in-valve procedure involves catheter-based valve implantation inside an already implanted bioprosthetic valve. This approach may provide an alternative to replacement of a degenerated surgically-implanted valve, or a means of salvaging suboptimal implantation of a catheter-based valve during the initial implantation procedure.

Preliminary reports have demonstrated the feasibility of transcatheter placement of a prosthetic valve within a degenerated bioprosthetic valve. As an example, valve-in-valve implantation was performed on 24 high-risk patients with aortic (n = 10), mitral (n = 7), pulmonary (n = 6), or tricuspid (n = 1) failed (stenotic and/or regurgitant) bioprostheses . Implantation was unsuccessful for one (mitral) case. There were no deaths during the procedure. There was one stroke and one death in 30 days; the death was related to attempted transseptal mitral positioning. The NYHA functional class improved from 88 percent in class III or IV at baseline to 88 percent in class I or II at last follow-up.

Valve-in-valve implantation has been used to salvage suboptimal initial transcatheter aortic valve implantation and significant paravalvular aortic regurgitation . In a series using Edwards SAPIEN valves, valve-in-valve implantation was performed in 0.6 percent of 463 retrograde procedures and 3.3 percent of 575 transapical antegrade procedures. In a series of 646 retrograde CoreValve procedures, moderate to severe aortic regurgitation during the implantation procedure was treated with balloon re-dilatation (in 21.2 percent of procedures) and/or valve-in-valve placement (in 2.6 percent) . None of the 628 patients with successful CoreValve implantation had greater than moderate aortic regurgitation.

One and two year outcomes — Longer term outcomes are illustrated by the following reports from multicenter registries:

One year outcomes were reported for 1038 patients from 32 centers in the European Edwards SAPIEN registry . Patients treated with the transapical approach (n = 575) have greater frequency of comorbidities and higher logistic EuroSCORE (29 versus 25.8 percent) compared to those treated with the transfemoral approach.

• One year mortality rates were 27.9 and 18.9 percent for transapical and transfemoral patients, respectively.
• Multivariable analysis identified logistic EuroSCORE, renal disease, liver disease, and smoking as the variables with the highest hazard ratios for one year mortality.

Early and two-year outcomes were reported for a multicenter cohort of 126 patients with symptomatic severe aortic stenosis who received the CoreValve between 2006 and 2008 . The mean logistic EuroSCORE was 23 percent. The cohort was retrospectively classified into moderate surgical risk (54 patients), high-risk operable (51 patients), and high-risk inoperable (21 patients) groups.

• The technical success rate was 83.1 percent. Thirty-day mortality was 15.2 percent without significant differences in the subgroups. Of note, this study started enrollment before other studies  and the lower observed technical success rate as well as higher early mortality rate are likely largely due to learning curve issues.
• At two years, mortality was 38.1 percent with a significantly higher mortality in the combined high-risk groups as compared to the moderate-risk group (45.8 versus 27.8 percent).
• Functional class improved in 80 percent of patients and remained stable at two-year follow-up. The mean aortic valve gradient was unchanged at two-year follow-up (8.5 at 30 days and 9.0 at two years).

The United Kingdom registry reported outcomes of two years for 870 patients undergoing 877 TAVR procedures (with a CoreValve or SAPIEN valve) from 2007 through 2009 . The mean logistic EuroSCORE was 18.5 percent.

• The procedural success rate was 97 percent. Thirty-day mortality was 7.1 percent. The in-hospital stroke risk was 4.1 percent.
• Mortality was 21.4 percent at one year and 26.3 percent at two years. There was no difference in mortality between the CoreValve and SAPIEN groups.
• In a multivariate model, the independent predictors of mortality were left ventricular ejection fraction <30 percent, the presence of moderate to severe aortic regurgitation, and chronic obstructive pulmonary disease.

Risk factors for early and late mortality were identified in a study of 663 patients undergoing TAVR with a CoreValve . Intraprocedural mortality was 0.9 percent. Mortality was 5.4 percent at 30 days and 15 percent at one year. Independent predictors of mortality at 30 days included certain procedural complications (conversion to open heart surgery, cardiac tamponade, major vascular or access site complications) as well as baseline characteristics (left ventricular ejection fraction <40 percent, prior balloon valvuloplasty, and diabetes mellitus). Independent predictors of mortality between 30 days and one year included prior stroke, postprocedural paravalvular leak ≥2+, prior acute pulmonary edema, and chronic kidney disease.



expert consensus document on transcatheter aortic valve replacement
http://www.sciencedirect.com/science/article/pii/S0735109712000022

Comparison of three methods of assessing cardiovascular disability

Class	New York Heart Association functional classification[1]	Canadian Cardiovascular Society functional classification[2]	Specific activity scale[3]
I	Patients with cardiac disease but without resulting limitations of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, dyspnea, or anginal pain.	Ordinary physical activity, such as walking and climbing stairs, does not cause angina. Angina with strenuous or rapid prolonged exertion at work or recreation.	Patients can perform to completion any activity requiring ≥7 metabolic equivalents, eg, can carry 24 lb up eight steps; do outdoor work (shovel snow, spade soil); do recreational activities (skiing, basketball, squash, handball, jog/walk 5 mph).
II	Patients with cardiac disease resulting in slight limitation of physical activity. They are comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnea, or anginal pain.	Slight limitation of ordinary activity. Walking or climbing stairs rapidly, walking uphill, walking or stair climbing after meals, in cold, in wind, or when under emotional stress, or only during the few hours after awakening. Walking more than two blocks on the level and climbing more than one flight of ordinary stairs at a normal pace and in normal conditions.	Patients can perform to completion any activity requiring ≤5 metabolic equivalents, eg, have sexual intercourse without stopping, garden, rake, weed, roller skate, dance fox trot, walk at 4 mph on level ground, but cannot and do not perform to completion activities requiring ≥7 metabolic equivalents.
III	Patients with cardiac disease resulting in marked limitation of physical activity. They are comfortable at rest. Less than ordinary physical activity causes fatigue, palpitation, dyspnea, or anginal pain.	Marked limitation of ordinary physical activity. Walking one to two blocks on the level and climbing one flight in normal conditions.	Patients can perform to completion any activity requiring ≤2 metabolic equivalents, eg, shower without stopping, strip and make bed, clean windows, walk 2.5 mph, bowl, play golf, dress without stopping, but cannot and do not perform to completion any activities requiring >5 metabolic equivalents.
IV	Patient with cardiac disease resulting in inability to carry on any physical activity without discomfort. Symptoms of cardiac insufficiency or of the anginal syndrome may be present even at rest. If any physical activity is undertaken, discomfort is increased.	Inability to carry on any physical activity without discomfort - anginal syndrome may be present at rest.	Patients cannot or do not perform to completion activities requiring >2 metabolic equivalents. Cannot carry out activities listed above (Specific activity scale III).

References:

1. The Criteria Committee of the New York Heart Association. Nomenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels, 9th ed, Little, Brown & Co, Boston, 1994. p.253.
2. Lucien C. Grading of angina pectoris. Circulation 1976; 54:5223.
3. Goldman L, Hashimoto B, et al. Comparative reproducibility and validity of systems for assessing cardiovascular functional class: Advantages of a new specific activity scale. Circulation 1981; 64:1227

TAVI -part1

Transcatheter aortic valve replacement

Aortic valve replacement is the mainstay of treatment of symptomatic aortic stenosis (AS). In properly selected patients, this surgical procedure offers substantial improvements in symptoms and life expectancy.

However, aortic valve surgery entails substantial risks for some patients with severe comorbidities, and for some considered at “extreme” risk, surgery is not appropriate. In others, technical limitations, eg, porcelain aorta, may mean that surgery is not feasible. Percutaneous aortic valvotomy was developed as a less invasive means to treat AS but has important limitations. Subsequently developed catheter-based techniques for aortic valve implantation may provide an alternative method for treating AS in patients with unacceptably high estimated surgical risks. A multidisciplinary team approach is recommended in approaching patients with symptomatic AS.

This topic will review transcatheter aortic valve implantation, which has been termed transcatheter aortic valve replacement (TAVR). Indications for aortic valve replacement, surgical aortic valve replacement, estimating the risk of aortic valve surgery, medical therapy of symptomatic AS, and percutaneous aortic valvuloplasty are discussed separately.

Transcatheter aortic valve replacement has been developed for the treatment of patients with severe symptomatic AS who have an unacceptably high estimated surgical risk, or in whom TAVR is preferred due to technical issues with surgery, eg, a porcelain aorta or prior significant mediastinal radiation, prior pericardiectomy with dense adhesions or prior sternal infection with complex reconstruction, or a patent left internal mammary graft lying beneath the sternum (as identified by computed tomography angiography).

Thus, accurate estimation of the risk of surgical aortic valve replacement performed by an experienced cardiothoracic surgeon and multidisciplinary valve team is vital to appropriate evaluation of potential candidates for this emerging experimental procedure. Risk calculators are available to estimate the risk of valvular surgery. However, risk estimates are subject to inaccuracies (eg, the logistic EuroSCORE appears to overestimate mortality risk in patients undergoing high-risk aortic valve replacement) and the models do not account for some clinical characteristics (eg, porcelain aorta, severe pulmonary hypertension, or RV dysfunction) that may impact surgical mortality. In patients undergoing aortic valve replacement, the Society of Thoracic Surgeons (STS) model may provide more accurate risk stratification than the logistic EuroSCORE or the Ambler risk score. The logistic EuroSCORE has been replaced by the EuroSCORE II.

Of note, these scoring systems are only applicable to patients undergoing surgery and are not validated nor considered accurate in a TAVR eligible cohort of patients. More appropriate scoring systems are not currently available, although they are being developed.

PATIENT SELECTION — Patient selection criteria for TAVR are evolving. Selected patients who have indications for aortic valve replacement for calcific aortic stenosis are candidates for TAVR. 

 The 2012 American College of Cardiology Foundation/American Association for Thoracic Surgery/Society for Cardiovascular Angiography and Interventions/Society of Thoracic Surgeons (ACCF/AATS/SCAI/STS) expert consensus document on
TAVR lists the following criteria based upon those used in randomized trials [1]:

• Calcific aortic valve stenosis with the following echocardiographic criteria:

• Severely calcified valve leaflets with reduced systolic motion AND 

Mean gradient >40 mm Hg or jet velocity >4.0 m/s

OR

Aortic valve area of <1.0 cm² or indexed effective orifice area <0.5 cm²/m² 

• In the setting of LV systolic dysfunction, severe AS is present when the leaflets are calcified, with reduced systolic motion, and dobutamine stress echocardiography shows an aortic velocity of >4.0 m/s OR mean gradient >40 mm Hg with a valve area <1.0 cm² OR AV index <0.6 cm²/m² at any flow rate.

• Patients are symptomatic (NYHA functional class II or greater) from aortic valve stenosis, rather than from symptoms related to comorbid conditions.
• A cardiac interventionalist and two experienced cardiothoracic surgeons agree that surgical aortic valve replacement is either precluded or high risk, based on a conclusion that the probability of death or serious irreversible morbidity exceeds the probability of meaningful improvement. At least one of the cardiac surgeon assessors must have physically evaluated the patient. The surgeon’s consult notes should specify the medical or anatomic factors leading to this conclusion and should include a printout of the calculation of the STS score.

The expert consensus document lists numerous exclusion criteria, including the following criteria related to the aortic valve:

• Bicuspid or unicuspid or noncalcified aortic valve
• Severe aortic regurgitation (>3+)
• Native aortic annulus size as measured by echocardiography <18 mm or >the largest annulus size for which a TAVR device is available (eg, 29 mm for the largest Medtronic CoreValve). Of note, this criterion is subject to change as the range of available device sizes changes.

Other exclusion criteria may include the following:

• Evidence (CK plus CK-MB elevation and/or troponin elevation) of an acute myocardial infarction within one month before the intended treatment.
• Hemodynamic or respiratory instability requiring inotropic support, mechanical ventilation, or mechanical heart assistance within 30 days of screening evaluation.
• Need for emergency surgery.
• Hypertrophic cardiomyopathy with or without obstruction.
• Left ventricular ejection fraction <20 percent.
• Severe pulmonary hypertension and right ventricular dysfunction.
• A known contraindication or hypersensitivity to all anticoagulation regimens or inability to be anticoagulated for the study procedure.
• Renal insufficiency (eg, creatinine >3.0 mg/dL) and/or end-stage renal disease requiring chronic dialysis.
• Echocardiographic evidence of intracardiac mass, thrombus, or vegetation.
• MRI confirmed CVA or TIA within six months (180 days) of the procedure.
• Severe incapacitating dementia.
• Estimated life expectancy <12 months due to noncardiac comorbid conditions.
• Severe mitral regurgitation.
• Significant aortic disease including the following abnormalities may preclude a transfemoral approach:

• Thoracic or abdominal aortic aneurysm (luminal diameter ≥5 cm), marked tortuosity (hyperacute bend)
• Aortic arch atheroma (especially if >5 mm thick, protruding, or ulcerated)
• Narrowing (especially with calcification and surface irregularities) of the abdominal or thoracic aorta
• Marked tortuosity (hyperacute bend) of the aorta or severe “unfolding” of the thoracic aorta

Two major catheter-based techniques for replacing the aortic valve have been investigated: retrograde percutaneous implantation and direct apical puncture. In addition, there is rapidly growing use of direct aortic access via either ministernotomy or right anterior thoracotomy.

An antegrade transseptal approach has also been studied but adoption has been limited due to procedural complexity and associated risks (eg, development of acute mitral regurgitation) .

A retrograde femoral arterial approach via the aortic arch and through the stenotic valve is an alternative to the antegrade approach, and devices were designed to overcome some of the limitations seen with transseptal antegrade delivery. Two stent-valve devices with different designs have been successfully implanted in humans using the retrograde femoral approach: a balloon-expandable valve (Edwards SAPIEN, which has replaced the Cribier-Edwards valve) and a self-expanding valve (Medtronic CoreValve) . The Medtronic CoreValve had also been delivered in a retrograde fashion from the subclavian/axillary artery and via direct aortic access via either ministernotomy or right anterior thoracotomy.

An alternate catheter-based approach consists of direct left ventricular apical puncture and antegrade aortic valve implantation via a small anterolateral thoracotomy without cardiopulmonary bypass or sternotomy. This approach is particularly suited to patients with severe peripheral artery disease and heavily calcified ascending aorta and arch (porcelain aorta) who have an increased risk of stroke and other embolic events using other approaches.

PERIPROCEDURAL MANAGEMENT

Candidates for TAVR should be evaluated for potential risk factors such as depressed left ventricular ejection fraction, coronary artery disease, and kidney disease . For patients at risk of hemodynamic decompensation, preparations should include availability of rapid institution of cardiopulmonary bypass (and rarely elective bypass may be instituted).

The expert consensus document recommends routine antibiotic prophylaxis for all patients undergoing TAVR prior to surgical incision or vascular access to prophylax against wound infection and endocarditis .

Patients undergoing TAVR generally receive general anesthesia, a temporary pacing lead, at least one large bore intravenous line, warming to avoid hypothermia, and monitoring by arterial line, pulmonary artery catheter, and transesophageal echocardiography.

Some transfemoral procedures are performed with local anesthesia and conscious sedation. Heparin is administered after placement of standard sheaths and prior to placement of the large sheath.

Management includes early identification and treatment of volume depletion, positive inotropic agents in patients with low cardiac output or greater than moderate pulmonary hypertension, and treatment of severe pulmonary hypertension and right ventricular failure with inhaled nitric oxide or epoprostenol.
Measures to avoid prolonged hypotension include maintenance of mean arterial pressure of >75 mmHg prior to initiation of rapid ventricular pacing (required during valve placement of prostheses other than the CoreValve) with cautious use of intravenous vasopressor (norepinephrine, epinephrine, or phenylephrine) therapy as needed while avoiding hypertension.

expert consensus document on transcatheter aortic valve replacement
http://www.sciencedirect.com/science/article/pii/S0735109712000022

Comparison of three methods of assessing cardiovascular disability

Class	New York Heart Association functional classification[1]	Canadian Cardiovascular Society functional classification[2]	Specific activity scale[3]
I	Patients with cardiac disease but without resulting limitations of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, dyspnea, or anginal pain.	Ordinary physical activity, such as walking and climbing stairs, does not cause angina. Angina with strenuous or rapid prolonged exertion at work or recreation.	Patients can perform to completion any activity requiring ≥7 metabolic equivalents, eg, can carry 24 lb up eight steps; do outdoor work (shovel snow, spade soil); do recreational activities (skiing, basketball, squash, handball, jog/walk 5 mph).
II	Patients with cardiac disease resulting in slight limitation of physical activity. They are comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnea, or anginal pain.	Slight limitation of ordinary activity. Walking or climbing stairs rapidly, walking uphill, walking or stair climbing after meals, in cold, in wind, or when under emotional stress, or only during the few hours after awakening. Walking more than two blocks on the level and climbing more than one flight of ordinary stairs at a normal pace and in normal conditions.	Patients can perform to completion any activity requiring ≤5 metabolic equivalents, eg, have sexual intercourse without stopping, garden, rake, weed, roller skate, dance fox trot, walk at 4 mph on level ground, but cannot and do not perform to completion activities requiring ≥7 metabolic equivalents.
III	Patients with cardiac disease resulting in marked limitation of physical activity. They are comfortable at rest. Less than ordinary physical activity causes fatigue, palpitation, dyspnea, or anginal pain.	Marked limitation of ordinary physical activity. Walking one to two blocks on the level and climbing one flight in normal conditions.	Patients can perform to completion any activity requiring ≤2 metabolic equivalents, eg, shower without stopping, strip and make bed, clean windows, walk 2.5 mph, bowl, play golf, dress without stopping, but cannot and do not perform to completion any activities requiring >5 metabolic equivalents.
IV	Patient with cardiac disease resulting in inability to carry on any physical activity without discomfort. Symptoms of cardiac insufficiency or of the anginal syndrome may be present even at rest. If any physical activity is undertaken, discomfort is increased.	Inability to carry on any physical activity without discomfort - anginal syndrome may be present at rest.	Patients cannot or do not perform to completion activities requiring >2 metabolic equivalents. Cannot carry out activities listed above (Specific activity scale III).

References:

1. The Criteria Committee of the New York Heart Association. Nomenclature and Criteria for Diagnosis of Diseases of the Heart and Great Vessels, 9th ed, Little, Brown & Co, Boston, 1994. p.253.
2. Lucien C. Grading of angina pectoris. Circulation 1976; 54:5223.
3. Goldman L, Hashimoto B, et al. Comparative reproducibility and validity of systems for assessing cardiovascular functional class: Advantages of a new specific activity scale. Circulation 1981; 64:1227

EVAR - the devices summary

SUMMARY  

for full paper
http://dqsendovascular.blogspot.kr/2012/10/evar-devices-part-1.html
http://dqsendovascular.blogspot.kr/2012/10/evar-devices-part2.html
http://dqsendovascular.blogspot.kr/2012/10/evar-devices-part-3.html

Endovascular repair with abdominal endograft devices is used primarily to treat infrarenal abdominal aortic aneurysm. Endovascular aortic repair requires that specific anatomic criteria be fulfilled, and for those with appropriate anatomy, this technique has become a preferred approach and allows the treatment of patients who might not otherwise be candidates for aortic repair.

Endovascular aortic repair involves the insertion of endovascular graft components, usually via a femoral approach. The endovascular graft is constructed in vivo by the delivery and deployment of these components in an established order. Upon deployment, the endograft expands, contacting the aortic wall proximally and aorta or iliac vessels distally to exclude the native, dilated portion of the aortic wall from aortic blood flow and pressure.

Although there are significant variations in endovascular graft design, three types of components are common to all: the delivery system, main body device, and device extensions. Devices available in the United States to treat the abdominal aorta include the AneuRx®, Zenith®, Excluder®, AFX and Powerlink®, Talent™, and Endurant® grafts. The characteristics for each graft are described above. (See 'Abdominal devices' above.)

When aortic disease is more extensive and involves branch vessels, the complexity of the repair and risk of complications increases. Approaches to manage more complicated anatomy include debranching procedures and the use of fenestrated and branched endografts. These endografts preserve blood flow into specific aortic branches depending upon the level of repair, but are available only for investigational use in the United States.

Several trials have compared endovascular aneurysm repair with open surgical repair using a variety of endografts for the treatment of infrarenal abdominal aortic aneurysm. These trials have consistently demonstrated significantly reduced perioperative (30-day) morbidity and mortality (1 to 2 versus 3 to 5 percent) for endovascular compared with open surgical repair; however, long-term mortality is not significantly different. Secondary intervention is frequently needed in patients who receive an abdominal endograft. As such, these devices require lifelong surveillance; the long-term outcomes for these devices continue to be studied.

The few comparisons that are available for specific endograft designs for the treatment of abdominal aortic aneurysm (AAA) have found no significant differences between devices for important outcomes. Because the graft design doesn’t appear to have a major impact on the outcomes of straightforward endovascular aneurysm repair, most operators choose one endograft for routine use, reserving others for one or more features that might be better suited to a specific patient.

Characteristics of abdominal endovascular devices

Endograft	Materials graft/support	Suprarenal fixation	Active proximal fixation/hooks	Native aortic neck diameter (range in mm)	Native iliac diameter (range in mm)	Maximum bifurcated main body device/introducer sheath diameter (French, OD*)	Potential advantages
AneuRx® (Medtronic)	Polyester/nitinol	No	No	20 to 26	8 to 22	21	Hydrophilic delivery system
Endurant® (Medtronic)	Polyester/ electropolished nitinol	Yes	Yes	19 to 32	8 to 25	20	Indications include short (10 mm) aortic neck, angulated neck
Powerlink® (Endologix)	PTFE/cobalt chromium alloy	Yes	No	18 to 32	10 to 23	17	Anatomic fixation at iliac bifurcation, low profile
Excluder® (Gore)	PTFE/nitinol	No	Yes	19 to 29	10 to 18.5	20	C3 delivery system, ability to recapture and reposition body, delivery sheath with hemostatic seal
Talent® (Medtronic)	Polyester/nitinol	Yes	No	18 to 32	8 to 22	24	Indication for short (10 mm) aortic neck, angulated necks
Zenith® (Cook Medical)	Polyester/stainless steel	Yes	Yes	18 to 32	8 to 20	26	Spiral Z flexible limbs

PTFE: polytetrafluoroethylene.
* OD: outer diameter.