1. Transcatheter or Surgical Aortic Valve Replacement in Intermediate Risk Patients with Aortic Stenosis
Description:
The goal of the trial was to assess the safety and efficacy of balloon-expandable transcatheter aortic valve replacement (TAVR) compared with surgical aortic valve replacement (SAVR) in intermediate-risk patients.
Contribution: The PARTNER 2A trial showed that TAVR is noninferior to SAVR for the primary endpoint at 2 years for the treatment of severe aortic stenosis in intermediate-risk patients (STS PROM 4-8%; median 5.8%).

2. Study Design
Patients were stratified in cohorts according to access route (transfemoral [76.3%] or transthoracic) and were then randomly assigned (in a 1:1 ratio) to undergo either TAVR (n = 1,011) or SAVR (n = 1,021).
TAVR was performed with the balloon-expandable TAVR Sapien XT valve system.
Total number of enrollees: 2,032
Duration of follow-up: 2 years
Mean patient age: 81.6 years
Percentage female: 46%

3. Other salient features/characteristics:
Median Society of Thoracic Surgeons (STS) PROM score: 5.8% (>5% had an STS PROM of >10%)
Coronary artery disease: 68%, cardiovascular disease: 32%, peripheral artery disease: 30%
Oxygen-dependent chronic obstructive pulmonary disease: 3.3%
5 m walk distance >7 seconds (measure of frailty): 45%
Left ventricular ejection fraction: 56%

4. Inclusion criteria:
Severe symptomatic aortic stenosis
STS PROM ≥4%. Patients with an STS risk score of <4.0% could also be enrolled if there were coexisting conditions that were not represented in the risk model
Heart team (including examining cardiac surgeon) agrees on eligibility including assessment that TAVR or SAVR is appropriate
Study patient agrees to undergo SAVR – if randomized to control treatment

5. Principal Findings:
Primary endpoint: All-cause mortality or disabling stroke for TAVR vs. SAVR at 2 years: 19.3% vs. 21.1%, p = for noninferiority, p = 0.33 for superiority
Also at 2 years (TAVR vs. SAVR):
All-cause mortality: 16.7% vs. 18.0%, p = 0.45
Cardiovascular mortality: 10.1% vs. 11.3%, p = 0.38
Disabling stroke: 6.2% vs. 6.4%, p = 0.83

6. Secondary outcomes for TAVR vs. SAVR:
Intraprocedural valve embolization: 0.1% vs. 0%
Intensive care unit length of stay: 2 vs. 4 days, p < 0.001
Index length of stay: 6 vs. 9 days, p < 0.001
All-cause mortality at 30 days: 3.9% vs. 4.1%, p = 0.78
Any neurological event at 30 days: 6.4% vs. 6.5%, p = 0.94; all strokes at 30 days: 5.5% vs. 6.1%, p = 0.57
Major vascular complication at 30 days: 7.9% vs. 5.0%, p = 0.008
Life-threatening or disabling bleeding at 30 days: 10.4% vs. 43.4%, p <
New atrial fibrillation at 30 days: 9.1% vs. 26.4%, p < 0.001
New permanent pacemaker at 30 days: 8.5% vs. 6.9%, p = 0.17
Rehospitalization at 2 years: 19.6% vs. 17.3%, p = 0.22
Aortic valve area at 2 years: 1.54 cm2 vs. 1.4 cm2, p < 0.001
Moderate to severe paravalvular aortic regurgitation (leak) (PVL) at 2 years:  8.0% vs. 0.6%, p < 0.001

7. Transfemoral access cohort:
All-cause mortality or disabling stroke at 2 years for TAVR vs. SAVR: 16.8% vs. 20.4%, hazard ratio 0.79, 95% confidence interval , p = 0.05

8. Interpretation:
The results of this trial indicate that TAVR is noninferior to SAVR for the primary endpoint of mortality/disabling stroke at 2 years for the treatment of severe symptomatic aortic stenosis in intermediate-risk patients (STS PROM score 4-8%; median 5.8%).
Transfemoral TAVR was possible in about 75% of the patients, and in these patients, TAVR appeared to be superior to SAVR.
Vascular complications were higher in TAVR patients at 30 days, while new-onset atrial fibrillation, acute kidney injury, and bleeding were higher in the SAVR arm.
Valve performance at 2 years was similar between the two strategies, although moderate to severe PVL was significantly higher in the TAVR arm at 2 years.