Aortic Valve Replacement can be considered in asymptomatic patients with severe aortic stenosis: AVATAR finds.

Key Points

• Severe aortic stenosis is associated with high mortality once patients become symptomatic. There is equipoise, however, as to whether patients with severe aortic stenosis need to be treated in the absence of symptoms.
• Current ACC/AHA guidelines recommend further provocative/exercise stress testing to determine whether patients with severe aortic stenosis are indeed symptomatic prior to valve replacement.
• AVATAR randomized asymptomatic patients with severe aortic stenosis and normal left ventricular function to watchful waiting or surgical AVR. Patients who underwent early surgery had a significantly lower endpoint of all cause mortality, acute myocardial infarction, stroke or heart failure hospitalization compared to the conservative management group. The trial was stopped early as the pre-specified event target was met

Despite the recent prevalence of aortic valve replacements with the advent of transcatheter aortic valve replacement (TAVR), valve replacement remains reserved for patients with severe aortic stenosis with symptoms or evidence of left ventricular dysfunction. Despite recent data to show that valve replacement is safe, and possibly indicated, for those without symptoms, international guidelines have not changed. The RECOVERY trial was the most recent to challenge this notion, by randomizing patients with asymptomatic very severe aortic stenosis (mean gradient of ≥50 mmHg or peak velocity ≥4.5 m/sec) to early surgery or conservative management. The trial showed that those who underwent surgery had a lower composite of operative mortality or death compared to those who did not. Despite this, there had yet to be a multicenter, multinational randomized control trial comparing surgery and conservative management in asymptomatic severe aortic stenosis. Until today.

During today’s Late-breaking session at the 2021 American Heart Association Scientific Sessions, Dr. Marko Banovic presented the results of the AVATAR Trial, performed across 9 medical centers in 7 European countries. Participants were included if 18 years of age or older, severe aortic stenosis as defined by a Vmax > 4 m/s or mean gradient >40 mmHg and aortic valve area ≤ 1.0 cm with an STS score <8%. Exercise testing was performed to confirm an absence of symptoms. Participants were excluded if they had evidence of left ventricular dysfunction, critical aortic stenosis defined by a Vmax >5.5 m/s, or the need for concomitant cardiac surgery.

The primary endpoint was a composite of all cause death and MACE comprising acute myocardial infarction, stroke and unplanned heart failure hospitalization. 157 patients were screened and randomized: 79 to the conservative management arm and 78 to the early surgery arm, of which 72 received surgery. Participants in each arm had degenerative etiologies for their valve disease, a low STS average score of 2.1, and robust LVEF of 69%. The trial was stopped by the Data and Safety Monitoring Board after the prespecified events were met, allowing for a median 32 months of follow up.  Of note, 25 patients initially randomized to the conservative arm were operated on due to either onset of symptoms or LV dysfunction.

The primary endpoint of all cause death, heart failure, MI and stroke was reached in 13 patients in the early surgery group and 26 patients in the conservative management group (HR 0.46; [95% CI 0.23 – 0.90]). Intraoperative death occurred in only one patient in the early surgery group.  “Our findings support the notion that aortic stenosis should be treated once it becomes significant, regardless of symptom status,” said Dr. Banovic during his presentation. While the panel agreed that the trial was impressive, they reiterated that it was a small trial, and could not alter practice in isolation.

 

The trial results were published simultaneously in CIRCULATION.