Transcatheter aortic valve implantation (TAVI) offers an effective, less invasive therapeutic alternative to surgical aortic valve replacement in patients with symptomatic, severe aortic stenosis. Although TAVI is demonstrated to be superior to medical therapy or surgery in patients who are at prohibitive or high risk for aortic valve surgery, less is known about TAVI in patients who are at low risk for complications or death from surgery. At EuroPCR 2021, Dr. John Forrest, Interventions for Valvular Disease, Yale University - New Haven, presented the complete 2-year follow-up from the Evolut low-risk trial.
The Evolut Low-Risk trial is a randomized noninferiority trial in which TAVI with a self-expanding supraannular bioprosthesis (CoreValve, Evolut R, or Evolut PRO; Medtronic) was compared with surgical aortic-valve replacement in patients who had severe aortic stenosis and were at low surgical risk (30-day surgical mortality risk<3%). The primary endpoint was a composite of death or disabling stroke at 24 months.
The as-treated cohort consisted of 1414 patients. Attempted TAVI or surgery was performed in 730 and 684 patients, respectively. Completed 2-year follow-up was available for 97.3% in the TAVI group and 92.3% in the surgery group. At 12 months, the primary outcome occurred in 2.5% in the TAVI vs. 4.3% in the surgical group (p=0.057). At 24 months, the primary outcome occurred in 4.3% in the TAVI vs. 6.3% in the surgical group (p=0.084). In a landmark analysis from 12 to 24 months, the primary outcome occurred in 1.9% in the TAVI vs. 2.1% in the surgical group (p=0.742); thereby indicating no late adverse catch-up phenomenon in the less-invasive TAVI therapy group.
Also additionally reported, at 2-years, TAVI with a self-expanding supraannular bioprosthesis was superior to surgery in regards to valve hemodynamics and prosthesis-patient mismatch. Conversely, surgery was superior to TAVI in regards to the incidence of pacemaker implantation and ³mild paravalvular leak.
These data are highly likely to encourage the offer of TAVI with a self-expanding supraannular bioprosthesis as a non-inferior, less invasive alternative treatment option to surgery for patients with symptomatic, severe aortic stenosis and low surgical risk. Physicians (and patients) are likely to interpret the results favorably with regards to the numerical values of the primary outcome of death or disabling stroke at 2-years between the two groups.
Physicians should counsel patients specifically regarding the higher rate of pacemaker implantation with TAVI (21.1%), however, these historical data do not incorporate the contemporary cusp-overlay implantation technique for the self-expanding supraannular bioprosthesis that significantly reduces conduction disturbance (and the need for subsequent pacemaker).
Longer-term follow-up is needed to evaluate the differences demonstrated in the impact on patient outcomes. Of note, patients will be followed for 10 years and so such data will be forthcoming.