Surgery or TAVR in intermediate risk? Results of the SURTAVI Study

Courtesy of Dr. Gustavo Leiva.

Transcatheter aortic-valve replacement (TAVR) with the use of a self-expanding prosthesis is superior to medical therapy in patients with severe, symptomatic aortic stenosis in whom surgical aortic-valve replacement has been associated with prohibitive risk. Among patients considered at high risk, TAVR may be an alternative to surgery.

The comparative efficacy of these procedures has been less studied among patients considered to be at lower surgical risk. The PARTNER 2 trial assessing the use of balloon-expandable devices as compared with surgery among intermediate-risk patients showed that TAVR was noninferior to surgery after a 2-year follow-up.

The purpose of the Surgical Replacement and Transcatheter Aortic Valve Implantation (SURTAVI) trial was to assess the safety and efficacy of TAVR vs. surgical aortic-valve replacement, with a self-expanding device in patients with intermediate risk for surgery. It was a multicenter, randomized, noninferiority study.

Patients randomized presented symptomatic, severe aortic stenosis (aortic-valve area <1 cm² or aortic-valve area index <0.6 cm² per square meter of body-surface area, mean gradient >40 mm Hg or aortic velocity >4 m/s at rest) and were deemed to be at intermediate surgical risk, which was defined as an estimated risk of surgical death at 30 days >4% and <15% (according to the criteria of the Society of Thoracic Surgeons Predicted Risk of Mortality [STS-PROM]).

The CoreValve prosthesis was used in 84% of patients, and last-generation self-expandable prosthesis Evolut R was used in 16% of patients. The use of cerebral protection systems was not permitted.

The primary endpoint of the study was a composite of all-cause death and disabling stroke at 24 months. As regards secondary endpoints, these included major adverse cardiovascular and cerebrovascular events (all-cause death, myocardial infarction, all types of strokes, and any reintervention).

The study randomized a total of 1660 patients (TAVR: 864; surgery: 796); the mean age was 79.8 ± 6.2 years; the STS-PROM score was 4.5 ± 1.6%, and most patients presented comorbidities, including diabetes (34.5% of patients) and chronic obstructive pulmonary disease (34% of patients), among others.

The incidence of the primary endpoint at 24 months was 12.6% in the transcatheter implantation group and 14.0% in the aortic-valve replacement surgery group, which proved that TAVR is noninferior to surgery in patients who are deemed to be at intermediate surgical risk. As regards secondary endpoints, no difference was observed in the incidence of myocardial infarction and both groups experienced improvement in their symptom status and quality of life.

Regarding hemodynamic parameters assessed through echocardiography, the TAVR group presented lower mean aortic-valve gradients and larger aortic-valve areas than the surgery group. At 1 year, the incidence of paravalvular regurgitation was higher in the TAVR group (5.3% vs. 0.6%). Patients who underwent surgery presented higher incidence of renal insufficiency within 30 days, higher incidence of atrial fibrillation, and higher incidence of transfusion. On the other hand, the TAVR group presented higher rates of vascular complications (6.0%) and of need for permanent pacemaker implantation (25.9%). Such a need for a permanent pacemaker was not associated to higher mortality during the 24-month follow-up.

Editorial Comment

The SURTAVI trial shows that transcatheter aortic valve replacement is noninferior to aortic-valve replacement surgery in patients deemed to be at intermediate surgical risk, when the self-expandable CoreValve system is used. This device was associated to a higher incidence of vascular complications and of need for a pacemaker. The rate of stroke was similar between the groups.

The next-generation self-expandable valve CoreValve Evolut R was used in less than 20% of patients. This may reflect a high rate of need for pacemaker implantation, since registry data for this device show a much lower pacemaker implantation rate.

Another important detail that should be emphasized is how low the 30-day mortality rate was in both groups (TAVR: 2,2%; surgery: 1.7%), one of the lowest rates ever reported in randomized studies.

As a conclusion, it can be said that transcatheter aortic valve implantation, both with a balloon-expandable system and a self-expandable system, could be used not only in patients who are not eligible for surgery or who present high surgical risk, but also in lower risk patients, given the results of the latest studies.

Courtesy of Dr. Gustavo Leiva. Department of Hemodynamics, Buenos Aires British Hospital.

Original title: Surgical or Transcatheter Aortic-Valve Replacement in Intermediate-Risk Patients. SURTAVI Investigators. NEJM March 17,2017.

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