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INTRODUCTION — 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 (extensively calcified ascending aorta and/or aortic arch), may mean that surgery is not feasible. Percutaneous aortic balloon 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 indications and clinical outcomes for 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, percutaneous aortic valvuloplasty, and complications of TAVR are discussed separately. (See "Indications for valve replacement in aortic stenosis in adults" and "Choice of prosthetic heart valve for surgical replacement" and "Estimating the mortality risk of valvular surgery" and "Medical management of symptomatic aortic stenosis" and "Percutaneous balloon aortic valvotomy".)
RATIONALE — Transcatheter aortic valve replacement (TAVR) has been developed for the treatment of patients with severe symptomatic aortic stenosis 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).
TAVR is now also widely used for the treatment of failed surgical bioprosthetic valves in the aortic position (so-called "valve-in-valve" procedure), and indications include bioprosthetic valve stenosis, regurgitation, or a combination of the two .
Approach to identifying candidates for TAVR — Indications for transcatheter aortic valve replacement (TAVR) are evolving. Patients may be referred for TAVR for treatment of native aortic valve stenosis, for valve-in-valve treatment of failure of a bioprosthetic aortic valve, or for native aortic valve regurgitation (with the last indication available in Europe but still investigational in North America).
●Among patients with symptomatic native aortic valve stenosis, a choice is made between surgical AVR (SAVR) or TAVR (or no intervention) based upon estimated surgical risk and comorbidities. (See 'For native aortic valve stenosis' below.)
●A valve-in-valve TAVR procedure is suggested for symptomatic patients with failure (regurgitation, stenosis, or both) of a surgically implanted bioprosthetic valve with high or greater risk for open surgical valve replacement. (See 'For bioprosthetic aortic valve failure' below.)
●In Europe, a transapical TAVR system (JenaValve) is an option to treat severe native aortic valve regurgitation in patients with high or greater risk for open surgical valve replacement or repair. (See 'For native aortic valve regurgitation' below.)
For native aortic valve stenosis — Patients with severe native calcific aortic stenosis (AS) are evaluated for presence of an indication for aortic valve replacement. Among patients with severe AS with an indication for valve replacement, a choice is made between SAVR or TAVR (or no intervention) based upon considerations including the estimated surgical risk and comorbidities. (See "Indications for valve replacement in aortic stenosis in adults".)
Indications for valve replacement for aortic stenosis — The choice of SAVR versus TAVR in patients with severe AS is made after it is determined that the patient meets an indication for valve intervention for severe AS . AVR is the mainstay of treatment of symptomatic AS, as it improves symptoms and prolongs survival. SAVR or TAVR is not indicated in patients with comorbidities that would preclude an expected benefit from correction of AS. (See "Indications for valve replacement in aortic stenosis in adults", section on 'Indications for valve replacement'.)
●AVR is recommended for patients with severe high-gradient AS who have symptoms by history or on exercise testing (stage D1).
●AVR is suggested in symptomatic patients with low-flow/low-gradient severe AS with reduced left ventricular ejection fraction (LVEF; stage D2) with a low-dose dobutamine stress study that shows an aortic velocity ≥4.0 m/s (or mean pressure gradient ≥40 mmHg) with a valve area ≤1.0 cm2 at any dobutamine dose.
●AVR is suggested in symptomatic patients who have low-flow/low-gradient severe AS (stage D3) who are normotensive and have an LVEF ≥50 percent if clinical, hemodynamic, and anatomic data support valve obstruction as the most likely cause of symptoms.
●AVR is recommended for asymptomatic patients with severe AS (stage C2) and LVEF <50 percent.
●AVR is suggested (weak recommendation) in asymptomatic patients (stage C1) with severe AS and decreased exercise tolerance or an exercise fall in blood pressure.
Choice of therapy — For patients who have severe AS and an indication for valve replacement, treatment decisions are made based upon individualized consideration of the estimated risk and benefit of the procedures, as well as existing comorbidities, including coronary artery disease. For patients being considered for TAVR or high-risk surgical AVR, a multidisciplinary heart valve team (including cardiologists, interventionalists, cardiovascular surgeons, anesthesiologists, and nurses) should collaborate to optimize care .
●For symptomatic patients with severe AS who have an indication for AVR and have low surgical risk (ie, STS-PROM <4), we recommend SAVR. (See 'In low-risk symptomatic patients' below.)
●For symptomatic patients with severe AS and an intermediate to high surgical risk (ie, STS-PROM ≥4), clinical studies suggest that either TAVR or SAVR is an option. The decision should be made by a Heart Valve Team with consideration of patient-specific factors (including the feasibility of transfemoral TAVR) and patient values and preferences.
The choice between TAVR and SAVR should also consider whether a bioprosthetic or mechanical valve is most appropriate in each patient. Concurrent conditions, including aortic dilation, coronary disease, and other valve lesions, may also affect this decision. (See 'In high-risk symptomatic patients' below and 'In intermediate-risk symptomatic patients' below.)
●For symptomatic patients with severe AS, a prohibitive surgical risk, and a predicted post-TAVR survival >12 months, we recommend TAVR rather than medical therapy. Asymptomatic patients with severe AS and prohibitive surgical risk should have frequent clinical evaluation to monitor for symptom onset. (See 'TAVR versus medical therapy in inoperable patients' below.)
●Asymptomatic patients with severe AS who have indications for AVR have heterogenous surgical risk; we recommend SAVR for most of these patients. Choice of treatment for patients at high surgical risk is individualized.
The above approach is similar to that in the 2014 American Heart Association/American College of Cardiology valve guideline (table 2) . However, the recommendation for TAVR with a self-expanding valve in patients with high surgical risk is based upon the United States CoreValve High Risk study, which was published after the guidelines . Recommendations for TAVR in intermediate-risk patients are also based on studies published after those guidelines. (See 'In high-risk symptomatic patients' below.)
Operative risk assessment (including identification of high and prohibitive risk) includes consideration of estimated operative mortality, frailty, major organ system compromised, and comorbidities (table 3). Accurate estimation of the risk of SAVR performed by an experienced cardiothoracic surgeon and multidisciplinary valve team is vital to appropriate evaluation of potential candidates. Risk assessment for valvular surgery is discussed further separately. (See "Estimating the mortality risk of valvular surgery".)
Although women experience more major bleeding and vascular complications with TAVR, female sex is an independent predictor of lower mortality after TAVR. Thus, sex-specific mortality risk following TAVR is opposite of that following SAVR, for which women have higher mortality risk than men. While the available data do not establish TAVR as superior to SAVR for women with high-risk symptomatic aortic stenosis, we suggest including female sex as a factor when weighing the potential risks and benefits of TAVR versus SAVR. (See 'Sex-specific differences in outcomes' below.)
Evidence — Evidence to support the above recommendations on choice of surgical or transcatheter intervention for AS is discussed separately.
Recommendations for SAVR for severe AS are based upon comparisons of the natural history of patients with AS with outcomes after SAVR. (See "Indications for valve replacement in aortic stenosis in adults", section on 'Evidence'.)
For patients with symptomatic severe AS, comparisons between SAVR and TAVR are grouped according to surgical risk:
●For patients with low surgical risk, a randomized trial compared one year outcomes for TAVR and SAVR. (See 'In low-risk symptomatic patients' below.)
●For patients with intermediate surgical risk, a randomized trial and an observational study compared outcomes with TAVR versus SAVR. (See 'In intermediate-risk symptomatic patients' below.)
●For patients with high surgical risk, randomized controlled trials serve as the basis for recommendations. (See 'In high-risk symptomatic patients' below.)
●For patients with AS with prohibitive surgical risk, recommendations are based upon a randomized trial and an observational study with historical control. (See 'TAVR versus medical therapy in inoperable patients' below and 'Self-expanding TAVR compared to historical control' below.)
For bioprosthetic aortic valve failure — A valve-in-valve procedure is an option for patients with failure (stenosis, regurgitation, or both) of a surgically implanted bioprosthetic aortic valve who are judged by a heart team, including a cardiac surgeon, to be at high or greater risk for open surgical therapy (ie, Society of Thoracic Surgeons operative risk score ≥8 percent or at a ≥15 percent risk of mortality at 30 days) . (See 'For prosthetic valve dysfunction treated with valve-in-valve' below.)
For native aortic valve regurgitation — SAVR remains the treatment of choice for patients with severe native valve aortic regurgitation. When surgery is absolutely contraindicated, TAVR is a potential option. In Europe, a transapical TAVR system (JenaValve) is approved to treat severe native aortic valve regurgitation in patients with high or greater risk for open surgical therapy. Off-label CoreValve use in this setting has been tried but is limited by risk of insufficient anchoring and risk of paravalvular aortic regurgitation. (See 'For native aortic valve regurgitation' below.)
EXCLUSIONS — Patients with a number of conditions are generally excluded from transcatheter aortic valve replacement (TAVR), as recommended in the 2012 American College of Cardiology Foundation/American Association for Thoracic Surgery/Society for Cardiovascular Angiography and Interventions/Society of Thoracic Surgeons expert consensus document on TAVR and the 2012 European Society of Cardiology valve guidelines (table 4) [6,7].
The following exclusion criteria for TAVR are related to the aortic valve:
●Bicuspid or unicuspid or noncalcified aortic valve. While a congenitally bicuspid aortic valve is generally considered an exclusion criterion for TAVR, TAVR has been successfully performed in some patients with this disorder, as discussed separately. Once severe calcific stenosis is present, reliable identification of the number of valve leaflets is problematic, so it is likely that TAVR has been performed in many patients with a congenital bicuspid valve. (See "Management of adults with bicuspid aortic valve disease", section on 'Transcatheter aortic valve replacement'.)
●Native aortic annulus size as measured by computed tomography is <18 mm (for a native valve), <17mm (for a surgical valve), or >the largest annulus size for which a TAVR device is available (eg, 29 mm). This criterion is subject to change as the range of available device sizes changes.
Note that valve size numbers do not correspond to actual annular measurements. Deciding which size valve to select for a given manufacturer is complex and is made using computed tomography annulus imaging area and perimeter measurements (with balloon expandable valves defined by area but self-expanding valve defined by perimeter).
●Severe native aortic regurgitation (>3+) is generally an exclusion criterion when TAVR is performed to treat native aortic valve disease; however, the JenaValve has CE Mark approval for use in Europe to treat native aortic valve stenosis and native aortic valve regurgitation.
The presence of severe aortic regurgitation is not an exclusion criterion when TAVR is performed as a valve-in-valve procedure to treat failed bioprosthetic valve.
●As noted above, TAVR is not recommended for patients with comorbidities that would preclude an expected benefit from correction of AS.
Other relative exclusion criteria that may be used include the following:
●Evidence (such as creatine kinase [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
●Magnetic resonance imaging-confirmed stroke or transient ischemic attack 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
SELECTION OF TAVR VALVE TYPE
Patient-specific considerations — For the majority of patients undergoing transcatheter aortic valve replacement (TAVR), either a Sapien, CoreValve, or one of the second generation devices are suitable. For patients treated at a center having sufficient experience with and access to many types of valves, there are certain patient-specific issues that might influence the choice of valve system type:
●Most valves types, but not all, cover the full range of annulus size.
●In a patient deemed to be at high risk of annulus rupture (eg, a patient with a small highly calcified annulus), a self-expanding rather than a balloon-expandable valve may be chosen to reduce the risk of annular rupture (as one of several potential strategies to attempt to reduce the risk of rupture). Annular rupture has been observed almost exclusively after use of a balloon-expandable valve and very rarely after use of a self-expandable valve . (See "Transcatheter aortic valve replacement: Overview of complications", section on 'Annular rupture'.)
●If there are concerns about coronary obstruction, then a valve system with recapturable technology may be favored.
●When performing a valve-in-valve procedure to treat a small surgical bioprosthetic valve, a supra-annular TAVR valve might offer greater effective orifice area.
Center-specific considerations — Operators have generally selected the type of TAVR valve to implant based upon local practice, operator training, medical center experience, and availability (based upon the regulatory approval status) rather than specific patient-related factors. Individual center procedure volume is an important factor in establishing and maintaining optimum patient outcomes. As a consequence, the majority of centers have implanted only one type of TAVR valve. While that landscape is changing, particularly in countries where there are multiple approved devices, maintenance of sufficient experience with each device used continues to be important for optimum patient outcomes. The differences in patient selection and procedural steps among competing device types are greater for various TAVR systems than for most other interventional cardiovascular procedures.
Regulatory status — Regulatory approvals govern the availability of TAVR technologies.
United States Food and Drug Administration approvals include the following:
●The Edwards SAPIEN XT (balloon-expandable) and the Medtronic CoreValve (self-expanding) systems are approved for patients with symptomatic severe native calcific aortic stenosis who are judged by a heart team, including a cardiac surgeon, to be at high or greater risk for open surgical therapy (ie, Society of Thoracic Surgeons operative risk score ≥8 percent or are judged by the heart team to be at a ≥15 percent risk of mortality at 30 days).
●The Edwards SAPIEN XT and Medtronic CoreValve are also approved for patients with failure (stenosis, regurgitation, or combined) of a surgical bioprosthetic aortic valve who are judged by a heart team, including a cardiac surgeon, to be at high or greater risk for open surgical therapy (ie, Society of Thoracic Surgeons operative risk score ≥8 percent or at a ≥15 percent risk of mortality at 30 days).
A number of TAVR systems have CE mark approval:
●The following devices are approved for use in Europe in patients with severe aortic stenosis at high or greater risk for surgical valve replacement: Medtronic CoreValve, Edwards SAPIEN, Direct Flow Medical (fully repositionable), St. Jude Medical Portico (repositionable prior to deployment), Medtronic Engager (transapical), JenaValve (transapical), Boston Scientific Lotus (repositionable prior to deployment), Medtronic Evolut R (self-expanding and repositionable prior to deployment), and Sapien 3 are approved for patients with severe aortic stenosis with high or greater risk for open surgical valve replacement.
●The CoreValve, Evolut R, and the Sapien XT valve are approved for valve-in-valve use in patients with high or greater risk for open surgical valve replacement.
●The JenaValve transapical TAVR system is also approved to treat severe native aortic valve regurgitation in patients who are inoperable or at high risk for open surgical therapy.
OUTCOMES — Transcatheter aortic valve replacement (TAVR) techniques are rapidly evolving, and results of published trials support the use of TAVR as the standard of care in certain patient subsets, and as a viable alternative to surgery in others. (See 'Indications' above.)
For treatment of native aortic valve stenosis — Outcomes of TAVR to treat native aortic valve stenosis have been evaluated in randomized trials and observational studies. Mortality and other complications following TAVR are discussed below.
A systematic review evaluated the effect of TAVR on functional status and quality of life in 60 observational studies (56 pre-post comparisons and four head-to-head comparative studies) and two randomized controlled trials . The review found that TAVR improved physical function at 12 months and New York Heart Association class at 6 to 11 months and at 12 to 23 months. A limitation of this analysis is that there were few head-to-head studies, and survivor bias may cause overestimation of the benefits.
TAVR versus medical therapy in inoperable patients — Evidence of a benefit of balloon-expandable TAVR compared with standard medical care for aortic stenosis was provided by the Placement of Aortic Transcatheter Valves (PARTNER) multicenter trial (cohort B) [10-13]. The investigators randomly assigned 358 patients with severe aortic stenosis who were not considered surgical candidates to either standard therapy (including balloon aortic valvotomy (see "Percutaneous balloon aortic valvotomy")) or TAVR with an Edwards SAPIEN valve via transfemoral approach. The mean age was 83 years and the mean Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) was 11.7 percent. The two treatment groups were similar, although the logistic EuroSCORE was slightly lower in the TAVR group (mean 26.4 versus 30.4). (See "Estimating the mortality risk of valvular surgery".)
The following findings were noted:
●At one year, the mortality rate was reduced with TAVR compared with standard therapy, including balloon aortic valvotomy (30.7 versus 50.7 percent). At two years, the mortality rates for TAVR and standard therapy were 43.4 and 68 percent; at three years, the mortality rates were 54.1 percent and 80.9 percent, and at five years, the mortality rates were 71.8 and 93.6 percent.
●Among survivors at one, two, three, and five years, functional class was better with TAVR versus standard therapy (eg, 86 versus 60 percent in New York Heart Association functional class I or II at five years).
●The stroke rate was significantly higher in the TAVR group than in the standard therapy group at 30 days (6.7 versus 1.7 percent), at two years (13.8 versus 5.5 percent), and three years (15.7 versus 5.5 percent). At five years, the risk of stroke was similar in the TAVR and standard therapy groups (16.0 versus 18.2 percent). A competing risk analysis showed no continuous hazard of stroke associated with TAVR after the initial procedural risk .
●In the standard 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 12.4 percent at 30 days, in 8.8 percent at one year, and in 4.5 percent at three years.
TAVR versus surgical therapy
In high-risk symptomatic patients — One randomized trial found similar mortality rates at five years in high-risk patients with aortic stenosis after balloon-expandable TAVR and surgical AVR (SAVR) [14,15]. In contrast, another randomized trial found a lower mortality rate at one year following self-expanding TAVR compared with surgical valve replacement in high-risk patients with aortic stenosis . Since data are not convincing that outcomes are different with different types of transcatheter heart valves, TAVR or SAVR is recommended for high-risk patients. (See 'Choice of therapy' above.)
A randomized trial comparing balloon-expandable TAVR with SAVR found similar mortality rates in the two treatment arms but there were higher rates of moderate to severe aortic regurgitation following TAVR [14-16]. The 699 patients in cohort A of the PARTNER trial were randomly assigned to undergo either balloon-expandable TAVR (by transfemoral or transapical approach) or SAVR. The mean age was 84 years and the mean STS-PROM was 11.7 percent. 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), two years (33.9 and 35 percent), and five years (67.8 and 62.4 percent).
●Combined strokes and transient ischemic attacks were more frequent after TAVR than after SAVR 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) and no significant difference at five years (15.9 versus 14.7 percent).
●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 versus 3.2 percent).
•SAVR 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; 14 versus 1 percent at five years). The presence of paravalvular aortic regurgitation was associated with increased late mortality as discussed below. (See "Transcatheter aortic valve replacement: Overview of complications", section on 'Paravalvular regurgitation'.)
A randomized trial comparing self-expanding TAVR to SAVR found a lower mortality rate in patients undergoing TAVR. In the United States CoreValve High Risk Study, 795 patients with severe aortic stenosis with high estimated surgical risk were randomly assigned to self-expanding TAVR or SAVR . The mean age was 83.2 years and the mean STS-PROM was 7.4 percent.
●Mortality rate at one year was lower in the TAVR group than in the surgical group (14.2 versus 19.1 percent).
●Major vascular complications, cardiac perforation, and permanent pacemaker implantation were more frequent after TAVR. Life-threatening or disabling bleeding, acute kidney injury, and new-onset or worsening atrial fibrillation were more frequent after surgery.
●TAVR was noninferior to surgical therapy with respect to echocardiographic indices of valve stenosis, functional status, and quality of life at one year.
●Exploratory analyses suggested a reduced rate of major adverse cardiovascular and cerebrovascular events at one year and no increase in risk of stroke at one year with TAVR.
In intermediate-risk symptomatic patients — For intermediate-risk patients with severe aortic stenosis, mortality and stroke rates are similar after TAVR and SAVR while complications differ as demonstrated by a randomized trial. The PARTNER 2A trial randomly assigned 2032 intermediate-risk patients with severe aortic stenosis to undergo either TAVR (with a balloon-expandable valve) or SAVR . The mean STS-PROM score was 5.8. Prior to randomization, patients were separated into two cohorts on the basis of an evaluation of the peripheral arteries: 76.3 percent were included in the transfemoral-access cohort and 23.7 percent were included in the transthoracic-access (transapical or transaortic) cohort.
●The rate of death from any cause or disabling stroke was similar in the TAVR and SAVR groups. At two years, the Kaplan-Meier event rates were similar: 19.3 percent in the TAVR group and 21.1 percent in the SAVR group.
•In the transfemoral-access cohort, TAVR resulted in a lower event rate than SAVR (hazard ratio, 0.79; 95% CI 0.62-1.00).
•In the transthoracic-access cohort, outcomes were similar in the TAVR and SAVR groups.
●TAVR resulted in larger aortic valve areas (mean 1.7 versus 1.5 cm2 at 30 days) and lower 30-day rates of acute kidney injury (1.3 versus 3.1 percent), severe bleeding (10.4 versus 43.4 percent), and new onset atrial fibrillation (9.1 versus 26.4 percent).
●SAVR resulted in less paravalvular aortic regurgitation (moderate or severe in 0.6 versus 3.7 percent at 30 days) and lower rates of major vascular complications (5 versus 7.9 percent at 30 days). Patients in the TAVR group with moderate or severe paravalvular aortic regurgitation at 30 days had higher mortality during two-year follow-up than did patients with no or trace aortic regurgitation.
An observational study suggested that TAVR with a balloon-expandable SAPIEN XT valve may be superior to SAVR for intermediate-risk patients . The study included 1077 patients with symptomatic severe aortic stenosis with intermediate-risk (STS-PROM score generally ≥4 percent; mean 5.2 percent) who underwent TAVR with a SAPIEN 3 valve. TAVR was performed via the transfemoral route in 88 percent of patients. Outcomes were compared with those for 944 patients in the SAVR arm of the PARTNER 2A randomized trial using a prespecified propensity score analysis. However, it is possible that residual confounders could have influenced the results.
●At one-year follow-up, all-cause mortality for the TAVR group was 7.4 percent (6.5 percent in the transfemoral access subgroup). Complications included disabling stroke (in 2 percent), aortic valve re-intervention (in 1 percent), and moderate or severe paravalvular regurgitation (in 2 percent).
●The primary composite end point was death from any cause, all strokes, and incidence of moderate or severe aortic regurgitation. TAVR was superior to SAVR for the composite end point as well as for the individual outcomes of death and stroke. Surgery was superior to TAVR in causing less frequent moderate or severe aortic regurgitation.
In low-risk symptomatic patients — Limited data are available on the best strategy for valve replacement in patients with aortic stenosis with low surgical risk. However, the relative benefit of TAVR compared with SAVR is unlikely to be greater than that seen in higher-risk patients, since low-risk patients are more likely to have good early post-surgical outcomes. In addition, long-term bioprosthetic valve durability and paravalvular aortic regurgitation are especially important in low-risk patients since they are generally expected to live longer than the high-risk group. Thus, the available evidence favors SAVR in patients with severe AS with low surgical risk.
The Nordic Aortic Valve Intervention Trial (NOTION) randomly assigned 280 patients with severe aortic stenosis with low and intermediate surgical risk to receive a self-expanding TAVR or SAVR . Most (81.8 percent) of the patients were considered low risk and the mean STS-PROM was 3. The composite primary outcome (death from any cause, stroke, or myocardial infarction at one year) and its components were similar in the two groups (13.1 versus 16.3 percent for the composite outcome). TAVR patients had larger improvements in effective orifice area but more frequently required pacemaker implantation, had more aortic valve regurgitation, and worse New York Heart Association functional class at one year. SAVR-treated patients had more major or life-threatening bleeding, cardiogenic shock, acute kidney injury, and new-onset or worsening atrial fibrillation.
In asymptomatic patients — Evidence is lacking on the use of TAVR in asymptomatic patients with severe aortic stenosis with indications for aortic valve replacement. However, the relative benefit of TAVR compared with SAVR is unlikely to be greater than that seen in symptomatic patients. In addition, long-term bioprosthetic valve durability and paravalvular aortic regurgitation are especially important in asymptomatic patients since they are generally expected to live longer than symptomatic patients. Thus, the available evidence favors SAVR in asymptomatic patients with severe AS.
Balloon-expandable versus self-expanding valves for aortic stenosis — Data directly comparing clinical outcomes in patients with aortic stenosis treated with balloon-expandable versus self-expanding valves are limited and a direct comparison of long-term clinical outcomes is not available.
A randomized trial in high-risk patients with aortic stenosis found that procedural success was more frequent with a balloon-expandable valve compared with a self-expanding valve  but one-year clinical outcomes were not significantly different . The Comparison of Transcatheter Heart Valves in High Risk Patients with Severe Aortic Stenosis (CHOICE) trial randomly assigned 241 patients to either the balloon-expandable Edwards SAPIEN XT valve or the self-expanding Medtronic CoreValve with the following results:
●Early outcomes :
•The primary early end point was device success (a composite of successful vascular access, device deployment, retrieval of the delivery system, correct device position, intended valve performance without moderate or severe regurgitation, and only one valve implanted in the proper anatomic location). Device success was achieved more frequently with the balloon-expandable valve than with the self-expandable valve (95.9 versus 77.5 percent). This difference was caused by a lower frequency of greater than mild aortic regurgitation and less need for implanting more than one valve in the balloon-expandable group.
•Cardiovascular mortality at 30 days was similar in the balloon-expandable valve and self-expandable valve groups (4.1 and 4.3 percent). The combined safety end point (all-cause mortality, major stroke, other serious complications) occurred at similar rates in the two groups (18.2 and 23.1 percent).
•Permanent pacemaker placement was less frequent in the balloon-expandable group (17.3 versus 37.6 percent).
●One-year outcomes :
•There were nominal differences in rates of all-cause mortality (17.4 versus 12.8 percent), cardiovascular mortality (12.4 versus 9.4 percent), stroke (9.1 versus 3.4), and repeat hospitalization for heart failure (7.4 versus 12.8) in the balloon- and self-expandable groups, but these differences were not statistically significant.
•Four patients in the balloon-expandable group developed elevated transvalvular gradient during follow-up; the gradients normalized with anticoagulant therapy, suggestive of a thrombotic etiology.
•Greater-than-mild paravalvular regurgitation was more frequently seen in the self-expandable group (1.1 versus 12.1 percent).
Further study, including an adequately powered study with long-term outcomes, is needed to compare balloon- and self-expanding valve types. As discussed below, observational studies of long-term outcomes have not found a significant difference related to device type (eg, United Kingdom registry discussed below). (See 'Data from registries' below.).
Self-expanding TAVR compared to historical control — Given the results of the PARTNER cohort B study, it was determined that a randomized trial comparing self-expanding TAVR and medical therapy could not be performed. The CoreValve Extreme Risk United States Pivotal Trial, a prospective single-arm study, compared TAVR with the self-expanding CoreValve to a pre-specified estimate of 12-month mortality or major stroke with medical therapy (43 percent, based upon results of a meta-analysis and data from the PARTNER cohort B) .
●For the 489 patients (mean age 83 years; mean STS-PROM 10.3) who underwent attempted treatment with the CoreValve transcatheter heart valve, the rate of all-cause mortality or major stroke at 12 months was 26 percent, which was significantly lower than the prespecified performance goal of 43 percent.
●Procedural events at 30 days included life-threatening/disabling bleeding in 12.7 percent, major vascular complications in 8.2 percent, and need for permanent pacemaker placement in 21.6 percent.
Data from registries — Additional information on outcomes following TAVR come from registry studies. Reports from the Society of Thoracic Surgeons/American College of Cardiology registry, the United Kingdom Transcatheter Aortic Valve Implantation registry, and the German Aortic Valve Registry (GARY) have included the following outcome data for patients with intermediate to high median risk (ie, STS-PROM 7.1  or 5  or logistic Euroscore 18.5 [25,26]):
●In-hospital stroke rates were 1.9 and 4.1 percent [23,25].
●One-year mortality rates were 23.7 and 21.4 percent [23,26].
●In the United Kingdom registry, mortality at two, three, and five years was 26.3, 38.8, and 54.5 percent [25,26].
In the United Kingdom registry, stroke within 30 days of TAVR was the only independent procedural predictor of mortality at three and five years . Independent predictors of three-year mortality were renal dysfunction, atrial fibrillation, respiratory dysfunction, and ventricular dysfunction. Coronary artery disease and age were independent predictors of mortality at five years. Device type, access route, and paravalvular leak did not independently predict long-term outcome.
Sex-specific differences in outcomes — Although women experience more major bleeding and vascular complications, female sex is an independent predictor of lower one-year mortality after TAVR. Thus, sex-specific mortality risk following TAVR is opposite of that following SAVR, for which women have higher mortality risk than men. We suggest including female sex as a factor when weighing the potential risks and benefits of TAVR versus SAVR, although the available data do not establish TAVR as superior to SAVR for women with high-risk symptomatic aortic stenosis.
A patient-level meta-analysis that included five studies with a total of 11,310 patients evaluated sex-specific outcomes . Following TAVR, women had higher rates of major vascular complications, major bleeding events, and stroke but a lower rate of moderate or greater aortic regurgitation. Thirty-day mortality rates were similar in women and men (6.5 percent for both) but female sex was an independent predictor of reduced mortality at follow-up at a median of 387 days (adjusted hazard ratio 0.79; 95% CI 0.73-0.86).
The largest single study of sex-specific outcomes included 2559 high-risk and inoperable patients with aortic stenosis undergoing TAVR in the randomized and nonrandomized portions of the PARTNER trial . Although women had lower baseline rates of hyperlipidemia, diabetes mellitus, smoking, and renal disease, they had significantly higher STS-PROM scores (11.9 versus 11.1 percent). Following TAVR, women had higher rates of vascular complications (17.3 versus 10 percent) and major bleeding (10.5 versus 7.7 percent) but less frequent moderate or greater paravalvular regurgitation (6 versus 14.3 percent). Thirty-day mortality rates were similar in women and men (6.5 versus 5.9 percent) but the one-year mortality rate was significantly lower in women (19 versus 24.9 percent). In multivariable analyses adjusting for baseline factors and for procedural complications, female sex was independently associated with lower one-year mortality.
A subgroup analysis of cohort A of the PARTNER trial (high-risk symptomatic aortic stenosis patients randomly assigned to TAVR or SAVR) found that women had lower mortality rates with TAVR compared with SAVR at six months and two-year follow-up, driven by the transfemoral arm . These differences in six-month and two-year mortality rates were not observed in men.
For prosthetic valve dysfunction treated with valve-in-valve — A valve-in-valve procedure involves catheter-based valve implantation inside an already implanted failed (stenotic, regurgitant, or both) bioprosthetic valve. This approach is an alternative to replacement of a degenerated surgically-implanted valve in patients who are at high risk for open surgical therapy (ie, STS-PROM ≥8 percent or a ≥15 percent risk of mortality at 30 days) (see 'For bioprosthetic aortic valve failure' above), or a means of salvaging suboptimal implantation of a catheter-based valve during the initial implantation procedure.
●Outcomes were reported for 459 multinational registry patients (mean age 77.6 years; 56 percent men) with a failed bioprosthetic surgical valve (stenosis in 39.4 percent, regurgitation in 30.3 percent, and combined in 30.3 percent) undergoing valve-in-valve implantation between 2007 and May 2013 . The median STS-PROM was 9.8 percent. Both balloon-expandable (53.6 percent) and self-expandable (46.4 percent) valves were implanted.
•At 30-day follow-up:
-The mortality rate was 7.6 percent and the stroke rate was 1.7 percent. The mortality rate was highest in patients with stenosis (10.5 versus 4.3 percent in the regurgitation group and 7.2 percent in those with combined stenosis and regurgitation).
-The balloon-expandable and self-expandable valve groups were similar in terms of mortality and stroke rate. Major/life-threatening bleeding and acute kidney injury events were more frequent in the balloon-expandable device group. Permanent pacemaker implantation was more frequent in the self-expandable device group.
-At least moderate aortic regurgitation was noted in 5.4 percent and was more common in the regurgitation group (9.4 versus 2.8 percent in the stenosis group and 5 percent in the combined group) and in the self-expandable device group (8.9 versus 2.4 percent in the balloon-expandable device group).
-Post-procedural residual aortic stenosis (lower mean orifice area and higher mean gradient) was greater in the stenosis group (mean orifice area 1.39 cm2 and mean gradient 18.5 mmHg) compared with the regurgitation (1.56 cm2 and 12 mmHg) and combined stenosis and regurgitation (1.56 cm2 and 16.1 mmHg) groups.
•At one-year follow-up:
-Overall one-year Kaplan-Meier survival rate was 83.2 percent.
-Survival rates were similar with balloon-expandable and self-expandable devices.
-Factors associated with mortality within one year included having baseline stenosis and a small (label size ≤21 mm) surgical bioprosthesis.
●Valve-in-valve implantation has also been used to salvage suboptimal initial TAVR and significant paravalvular aortic regurgitation [30,31]. Among 2554 consecutive patients undergoing balloon-expandable TAVR in the PARTNER trial, 63 (2.5 percent) required acute insertion of a second transcatheter prosthesis (valve-in-valve), most commonly for initial post-TAVR aortic regurgitation . In spite of similar valve function on follow-up echocardiography, patients requiring salvage valve-in-valve TAVR had significantly higher cardiovascular mortality (HR 1.86; 95% CI 1.03-3.38) and a nonsignificant trend toward higher overall mortality compared with those not requiring salvage valve-in-valve TAVR.
For native aortic valve regurgitation — Severe (>3+) native aortic regurgitation is generally an exclusion criterion when TAVR is performed to treat native aortic valve disease [3,6,7]. Issues raised with off-label use of first generation transcatheter heart valve devices to treat aortic regurgitation include risk of insufficient anchoring of the transcatheter heart valve within the noncalcified aortic annulus and risk of residual aortic regurgitation with resulting high rate (18.8 percent) of acute valve-in-valve implantations .
The JenaValve is a second-generation transcatheter heart valve that features a clip fixation of the native aortic valve cusps that enables secure anchorage even in the absence of calcifications . The feasibility of using the JenaValve to treat native aortic regurgitation was illustrated by an observational study that included 31 patients with severe aortic regurgitation undergoing transapical TAVR with a JenaValve at nine German centers . A valve-in-valve procedure was required in one patient following transcatheter heart valve dislodgement. During six-month follow-up one additional patient required a valve-in-valve implantation for increasing paravalvular regurgitation and one patient required SAVR for endocarditis. Mortality was 12.9 percent at 30 days and 19.3 percent at six months.
The JenaValve has received CE Mark approval for use in Europe to treat native aortic valve stenosis and native aortic valve regurgitation.
SUMMARY AND RECOMMENDATIONS
●Surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR) are the mainstay of treatment of symptomatic aortic stenosis (AS), as they improve symptoms and prolong survival. SAVR or TAVR are not indicated in patients with comorbidities that would preclude an expected benefit from correction of AS. (See 'Indications for valve replacement for aortic stenosis' above and "Indications for valve replacement in aortic stenosis in adults", section on 'Indications for valve replacement'.)
●For patients being considered for TAVR or intermediate- or high-risk SAVR, a multidisciplinary heart valve team (including cardiologist, cardiovascular surgeon, and interventionalist) should collaborate to optimize care. (See 'Choice of therapy' above.)
●While both TAVR and SAVR are effective therapies for severe AS, their complication profiles differ. TAVR entails greater risk of paravalvular aortic regurgitation and major vascular complications. SAVR entails greater risk of major bleeding, acute kidney injury, and new onset atrial fibrillation. (See "Transcatheter aortic valve replacement: Overview of complications".)
●For symptomatic patients who have severe AS, the choice of therapy is based upon consideration of the estimated risk and benefit of the procedures, as well as existing comorbidities.
•For symptomatic patients with AS who have an indication for AVR and have low surgical risk (ie, STS-PROM <4), we recommend SAVR rather than TAVR (Grade 1B). (See 'In low-risk symptomatic patients' above.)
•For symptomatic patients with severe AS and an intermediate to high surgical risk (ie, STS-PROM ≥4), clinical studies suggest that either TAVR or SAVR is an option. The choice between SAVR and TAVR should be made by a Heart Valve Team with consideration of patient specific factors (including the feasibility of transfemoral TAVR) and patient values and preferences. (See 'In high-risk symptomatic patients' above and 'In intermediate-risk symptomatic patients' above.)
•For symptomatic patients with severe AS, a prohibitive surgical risk, and a predicted post-TAVR survival >12 months, we recommend TAVR rather than medical therapy (Grade 1B). (See 'TAVR versus medical therapy in inoperable patients' above.)
●Asymptomatic patients with severe AS who have indications for AVR have heterogenous surgical risk; we recommend SAVR for most of these patients. Choice of treatment for patients at high surgical risk is individualized. (See 'Choice of therapy' above.)
●For symptomatic patients with failed (stenotic, regurgitant, or both) surgical bioprosthetic aortic valve with high or greater surgical risk, we suggest TAVR rather than SAVR (Grade 2C). (See 'For bioprosthetic aortic valve failure' above and 'For prosthetic valve dysfunction treated with valve-in-valve' above.)
●In Europe, a transapical TAVR system (JenaValve) is an option to treat severe native aortic valve regurgitation in patients with high or greater risk for open surgical valve replacement or repair. (See 'For native aortic valve regurgitation' above and 'For native aortic valve regurgitation' above.)
●TAVR provided a survival benefit over standard medical therapy (including percutaneous balloon valvotomy) in patients with inoperable severe symptomatic aortic stenosis (AS) in the following studies:
•A randomized trial found that balloon-expandable TAVR provided better survival than standard therapy, including percutaneous valvotomy. However, a higher stroke rate was observed following TAVR. (See 'TAVR versus medical therapy in inoperable patients' above.)
•An observational study found that self-expanding TAVR had better survival than expected with standard therapy. (See 'Self-expanding TAVR compared to historical control' above.)
●In randomized trials enrolling patients with severe symptomatic AS deemed to be at high or intermediate risk for surgery, mortality rates were similar following balloon-expandable TAVR and SAVR. The mortality rate following self-expanding TAVR was lower than with SAVR in high-risk patients. (See 'TAVR versus surgical therapy' above.)
●Data directly comparing clinical outcomes with balloon-expandable and self-expanding valve are limited. Further study, including an adequately powered study with long-term outcomes, is needed to compare balloon- and self-expanding valve types. (See 'Balloon-expandable versus self-expanding valves for aortic stenosis' above.)
●A valve-in-valve procedure involves catheter-based valve implantation inside an already implanted failed (stenotic or regurgitant or both) bioprosthetic valve. Among patients undergoing a valve-in-valve procedure, a stenotic valve is a risk factor for 30-day and one-year mortality. (See 'For prosthetic valve dysfunction treated with valve-in-valve' above.)
●The long-term durability of transcatheter bioprosthetic valves is not yet known. (See 'Outcomes' above.)
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