For patients with asymptomatic severe aortic stenosis (AS) and preserved left-ventricular ejection fraction, current guidelines recommend clinical surveillance every six to twelve months. It still remains unclear whether early transcatheter aortic valve replacement (TAVR) provides advantages over the guideline-recommended clinical surveillance. Now, the first powered randomized trial evaluating early intervention with TAVR in patients with asymptomatic severe AS has found that this strategy is both safe and effective compared to clinical surveillance.

The study conducted at the Gagnon Cardiovascular Institute (Morristown, NJ, USA) involved 1,578 patients who consented for screening at 75 centers in the United States and Canada from March 2017 through December 2021. Among them, 901 patients were randomized to receive either transfemoral TAVR or clinical surveillance. The mean age of participants was 76 years, with 69% being male, and the mean Society of Thoracic Surgeons risk score was 1.8%. Additionally, 84% of the patients were assessed as low surgical risk according to evaluations by local heart teams. Asymptomatic status was confirmed in over 90% of patients via negative treadmill stress tests, and the mean Kansas City Cardiomyopathy Questionnaire score at baseline was an excellent 92.7. The baseline echocardiographic characteristics were comparable between the two groups.

The primary endpoint of the study, which was a composite of death, stroke, or unplanned cardiovascular hospitalization, was assessed for superiority in the intent-to-treat population following a minimum follow-up of two years. The findings, published in the New England Journal of Medicine, indicated that early TAVR led to a significant reduction in the primary endpoint at two years, as well as during a median follow-up of 3.8 years, with incidences of 35.1% in the TAVR group compared to 51.2% in the surveillance group. Moreover, the secondary endpoint of favorable health status occurred more frequently in the early TAVR group (86.6%) than in the surveillance group (68%).

Additionally, left-ventricular and left-atrial health at the two-year mark was found to be superior in patients who underwent early TAVR. Changes in left-ventricular ejection fraction from baseline to two years, the onset of new atrial fibrillation, and rates of death or disabling stroke were similar between the two groups. Notably, by the two-year follow-up, over 70% of patients in the clinical surveillance group required aortic valve replacement (AVR), with most of them developing symptoms. The median time to conversion to AVR was 11.1 months, with 26% and 47% of patients needing AVR at six months and one year, respectively. Alarmingly, approximately 40% of patients in the clinical surveillance group exhibited acute and advanced symptoms, including NYHA class III-IV heart failure, pulmonary edema, or syncope.

“Given the benefits observed and the lack of harm, early TAVR may be preferred to clinical surveillance in patients with asymptomatic severe AS, especially when combined with the challenges of timely symptom recognition and prompt treatment in real-world settings,” said Philippe Généreux, MD, Director of the Structural Heart Program at the Gagnon Cardiovascular Institute. “Not only is early intervention safe and effective, but it also prevents a decline in quality of life for those who later receive TAVR and could prevent the development of cardiac damage.” 

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