Nordic Aortic Valve Intervention - NOTION

Contribution To Literature:

The NOTION trial suggests that 1-year outcomes following TAVR and SAVR were similar in low-risk patients with severe degenerative aortic stenosis.

Description:

The goal of the trial was to compare outcomes after transcatheter aortic valve replacement (TAVR) versus surgical aortic valve replacement (SAVR) in unselected patients with severe degenerative aortic stenosis.

Study Design

Patients were randomized in a 1:1 fashion to either TAVR (n = 145) or SAVR (n = 135). Patients in the TAVR group received the Medtronic CoreValve self-expanding prosthesis. Transfemoral access was performed in 96.5% of the patients; cross-over to SAVR was 2.1%. Nearly 89% received either a 26 or 29 mm prosthesis. All SAVR patients received a bioprosthetic valve.

Patient population:

  • Total number of enrollees: 280
  • Duration of follow-up: 1 year
  • Mean patient age: 79.1 years
  • Percentage female: 47%
  • Percentage diabetics: 10%
  • New York Heart Association (NYHA) class II/III symptoms (93%)
  • Society of Thoracic Surgeons (STS) predicted risk of mortality (PROM) score: 3.0 (81.8% with STS score <3%), Logistic EuroSCORE: 8.6
  • Peripheral arterial disease: 6%
  • Chronic lung disease: 12%
  • Pre-existing pacemaker: 4%

Inclusion criteria:

  • Age ≥70 years
  • Severe degenerative aortic stenosis
  • Deemed eligible for either procedure by Heart Team
  • Life expectancy >1 year

Exclusion criteria:

  • Other severe valvular disease
  • Coronary artery disease requiring treatment
  • Previous cardiac surgery
  • Myocardial infarction (MI) or stroke within 30 days
  • Severe renal failure requiring dialysis
  • Pulmonary failure with a forced expiratory volume within 1 second or diffusion capacity below 40% of expected

Principal Findings:

The primary composite outcome, all-cause mortality, MI, stroke for TAVR vs. SAVR at 1 year, was 13.1% vs. 16.3%, p = 0.43. Mortality: 4.9% vs.7.5%, p = 0.38.

Secondary outcomes at 30 days:

  • Major vascular complications: 5.6% vs. 1.5%, p = 0.10
  • Cerebrovascular accident: 2.8% vs. 3.0%, p = 0.94
  • Cardiogenic shock: 4.2% vs. 10.4%, p = 0.05
  • Major, life-threatening, or disabling bleeding: 11.3% vs. 20.9%, p = 0.03
  • New onset or worsening atrial fibrillation (16.9% vs. 57.8%, p < 0.0001)
  • Permanent pacemaker implantation: 34.1% vs. 1.6%, p < 0.001

Secondary outcomes at 1 year:

  • Moderate to severe aortic regurgitation: 15.7% vs. 0.9%, p < 0.001
  • NYHA class II symptoms: 29.5% vs. 15.0%, p = 0.01

5-year outcomes: The primary endpoint for TAVR vs. SAVR was 39.2% vs. 35.8%, p = 0.78.

  • All-cause mortality: 27.7% vs. 27.7%, p = 0.9
  • Stroke: 10.5% vs. 8.2%, p = 0.67
  • Pacemaker; 41.8% vs. 8.4%, p < 0.001
  • Aortic valve reintervention: 2.5% vs. 0%, p = 0.09, endocarditis: 11.3% vs. 5.8%, p = 0.10
  • Effective orifice area at 5 years: 1.66 vs. 1.23 cm2, MG: 8.2 vs. 13.7 mm Hg, both p < 0.001

Interpretation:

The results of this trial indicate that among patients with severe degenerative aortic stenosis with mostly low STS PROM scores, TAVR with the first-generation CoreValve self-expanding prosthesis results in similar 1-year clinical outcomes as SAVR. Stroke risk was similar as well. SAVR resulted in more bleeding complications and atrial fibrillation, while TAVR patients had more aortic regurgitation, less symptomatic benefit, and a higher need for a permanent pacemaker.

At 5 years, rates of death, MI, and stroke were comparable between patients undergoing TAVR and SAVR, although in patients with STS ≥4, the results seemed to favor SAVR. The latter observation is counter to the results of the intermediate-risk TAVR trials (PARTNER 2A and SURTAVI), and may be a chance finding. Hemodynamic performance of even the first-generation valve appears to be superior to SAVR, although paravalvular leak rates were higher with TAVR.

Currently, in the United States, TAVR is approved for intermediate- and high-risk (STS PROM ≥3%) and inoperable patients only. Although this trial is relatively small, the results are fairly interesting since patients enrolled were predominantly low-risk (STS <3%). Thus, at a broad level, both strategies appear to perform similarly, even in low-risk patients. However, patients in the TAVR arm had higher aortic regurgitation and permanent pacemaker requirements; the latter is associated with worse long-term mortality. Also, nearly 80% of screened patients in this trial were excluded; the overall generalizability is thus unclear (although this was meant to be an all-comers trial). Trials with contemporary TAVR devices in low-risk populations are ongoing and will help further inform the field on this important issue.

References:

Presented by Dr. Hans Thyregod at the American College of Cardiology Annual Scientific Session (ACC 2018), Orlando, FL, March 10, 2018.

Thyregod HG, Steinbrüchel DA, Ihlemann N, et al. Transcatheter Versus Surgical Aortic Valve Replacement in Patients With Severe Aortic Valve Stenosis:

1-Year Results From the All-Comers NOTION Randomized Clinical Trial. J Am Coll Cardiol 2015;65:2184-2194.

Presented by Dr. Hans Thyregod at the American College of Cardiology Annual Scientific Session (ACC 2015), San Diego, CA, March 15, 2015.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and VHD, Interventions and Structural Heart Disease

Keywords: ACC18, ACC Annual Scientific Session, Transcatheter Aortic Valve Replacement, Aortic Valve, Aortic Valve Stenosis, Arteries, Heart Valve Diseases, Heart Valve Prosthesis, Myocardial Infarction, Stroke, Surgeons


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