A Prospective, Randomized Trial of Transapical Transcatheter Aortic Valve Implantation vs. Surgical Aortic Valve Replacement in Operable Elderly Patients With Aortic Stenosis - STACCATO

Description:

The landmark PARTNER trial demonstrated the superiority of transcatheter aortic valve replacement (TAVR) over medical therapy in patients with inoperable severe aortic stenosis (cohort B), and the noninferiority of TAVR as compared with surgical AVR in patients who were at high risk for surgery (Society of Thoracic Surgeons [STS] score ≥8%) (cohort A).

The current trial sought to compare outcomes after transapical TAVR as compared with surgical AVR in elderly patients with severe aortic stenosis who were otherwise not at an elevated risk for undergoing surgical AVR.

Hypothesis:

Transapical TAVR would be superior to surgical AVR in elderly patients with severe aortic stenosis who were otherwise not at an elevated risk for undergoing surgical AVR.

Study Design

  • Randomized
  • Parallel

Patient Populations:

  • Valvular aortic stenosis (valve area <1 cm2)
  • Age ≥75 years
  • Condition accessible both by surgical aortic valve replacement and transapical transcatheter aortic valve implantation
  • Expected survival >1 year following successful treatment

    Number of screened applicants: 525
    Number of enrollees: 70
    Duration of follow-up: 3 months
    Mean patient age: 81 years
    Percentage female: 70%
    Ejection fraction: 56.4%
    NYHA class: 52% (III/IV)

Exclusions:

  • Coronary artery disease to be treated by percutaneous coronary intervention (PCI) or coronary artery bypass grafting
  • Previous myocardial infarction, or cardiac surgery or PCI within 12 months
  • Need for emergency surgery
  • Unstable cardiac condition (assist device or inotropes)
  • Stroke within 1 month
  • Reduced pulmonary function
  • Renal failure to be treated by hemodialysis

Primary Endpoints:

  • 30-day all-cause mortality, stroke, renal failure

Secondary Endpoints:

  • Myocardial infarction
  • Operation for bleeding
  • Permanent pacemaker treatment
  • Duration of hospital stay
  • Echocardiographic parameters (aortic valve area, peak aortic valve gradient, aortic valve leakage, left ventricular ejection fraction)
  • NYHA class, Short Form-36 composite physical and mental functional scores

Principal Findings:

The investigators planned to enroll 200 patients, but the Data Safety and Monitoring Board terminated the trial early after enrollment of 70 patients. Of these 70 patients, 34 underwent transapical TAVR and 36 underwent surgical AVR. Baseline characteristics were fairly similar between the two arms. The mean STS score was 3.3, with a corresponding mean logistic EuroSCORE of 10. About 2.9% had prior cerebrovascular accident, and 7% had evidence of peripheral artery disease. About one half of the patients (52%) were significantly symptomatic (New York Heart Association [NYHA] class III/IV). The mean aortic valve area was 0.7 cm2.

The primary endpoint of all-cause mortality, stroke, or renal failure requiring dialysis was elevated in the transapical TAVR arm as compared with the surgical AVR arm (14.7% vs. 2.8%, p = 0.07). There was a higher incidence of death (8.8% vs. 0%) and stroke (5.9% vs. 2.8%). Other significant events at 3 months were also higher in the transapical TAVR arm (23.5% vs. 5.6%). This included one death, one stroke, and one aortic rupture in the transapical TAVR arm. Both aortic valve area and peak aortic valve gradient were significantly improved in both arms at follow-up, with no difference between the two arms.

The incidence of paravalvular aortic regurgitation was significantly higher in the transapical TAVR arm (moderate/severe: 13% vs. 0%; minimal: 43% vs. 6%; p < 0.001). The incidence of permanent pacemaker implantation was 5.8% vs. 2.7%, p = 0.52, and mean hospital stay was 8.8 vs. 7.6 days, p = 0.32.

Interpretation:

The results of this small trial indicate that transapical TAVR is not superior to surgical AVR in elderly patients with severe aortic stenosis and low STS scores (mean 3.3) who are otherwise candidates for surgical AVR; outcomes including mortality and strokes were all elevated in the transapical arm at 30 days and at 3 months.

Although underpowered, these results are sobering, and suggest that transapical TAVR (in its current stage of development) use should be restricted to patients who are at high risk, as studied in the PARTNER trial; indiscriminate use in patients who are otherwise good operative candidates may not be in their best interest. The relative merits of transapical versus transfemoral TAVR need to be examined in future studies.

References:

Presented by Dr. Leif Thuesen at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2011), San Francisco, CA, November 10, 2011.

Clinical Topics: Cardiac Surgery, Vascular Medicine

Keywords: Renal Dialysis, Heart Valve Prosthesis, Stroke, Renal Insufficiency, Follow-Up Studies, Research Personnel, Peripheral Arterial Disease, Length of Stay


< Back to Listings