Midterm Survival Rates High in Asymptomatic Aortic Stenosis, Early Intervention Useful in Severe Cases Outcomes of Patients With Asymptomatic Aortic Stenosis Followed Up in Heart Valve Clinics

A study by published in JAMA cardiology indicated that the potential benefit of early intervention must be considered in high-risk AS patients. Cases of asymptomatic AS followed up in heart valve centers had a good midterm survival rate. However, patients with severe AS at baseline and peak aortic jet velocity of 5.0 m/s or greater or LVEF less than 60% had increased risks of all-cause and cardiovascular mortality even after AVR, according to Patrizio Lancellotti, M.D., Ph.D., of University of Liège Hospital in Belgium, and colleagues. The investigators also identified certain factors that correlated with poorer prognosis.

The evaluation and treatment of patients with valvular heart disease (VHD) have evolved considerably over the past decade in direct relation to an enhanced understanding of natural history, refinements in multimodality imaging, improvements in surgical techniques and outcomes, and the transformative emergence of transcatheter valve replacement and repair. Collectively, these changes have prompted valve intervention at earlier stages in the natural history of heart valve disease. In order to determine the clinical outcomes of patients with asymptomatic AS using data from the Heart Valve Clinic International Database, Lancellotti, and his colleagues assembled this registry by merging data from prospectively gathered institutional databases from 10 heart valve clinics in Europe, Canada, and the United States. Asymptomatic patients with an aortic valve area of 1.5 cm² or less and preserved left ventricular ejection fraction (LVEF) greater than 50% at entry were considered for the present analysis. Data were collected from January 2001 to December 2014, and data were analyzed from January 2017 to July 2018. The main outcomes studied included the natural history, need for aortic valve replacement (AVR), and survival of asymptomatic patients with moderate or severe AS at entry followed up in a heart valve clinic. Indications for AVR were based on current guideline recommendations. Predictors of mortality in patients with severe AS included: a peak aortic jet velocity over 5 m/s, left ventricular ejection fraction (LVEF) less than 60%, older age, higher systolic blood pressure, and chronic obstructive pulmonary disease.

In this study, the investigators found that of the 1375 patients included in this analysis, 60.7% were male, and the mean (SD) age was 71 (13) years. A total of 62.6% of patients had severe AS (aortic valve area less than 1.0 cm²). Survival rates with medical management were 93% at 2 years, 86% at 4 years, and 75% at 8 years, according to the pooled institutional databases of 10 heart valve clinics in Europe, Canada, and the U.S. A total of 7.6% of patients died under observation, including 54.8% from cardiovascular causes. The crude rate of sudden death was 0.65% over the duration of the study. A total of 39.4% patients underwent AVR, including 71.6% with severe AS at study entry and 28.4% with moderate AS at entry who progressed to severe AS. Those with severe AS at entry who underwent AVR did so at a mean (SD) of 14.4 (16.6) months and a median of 8.7 months. The mean (SD) 2-year and 4-year AVR-free survival rates for asymptomatic patients with severe AS at baseline were 54% (2%) and 32% (3%), respectively. For those who did get transcatheter or surgical AVR, the procedure was associated with a “very low” 0.9% rate of 30-day mortality. In patients with severe AS at entry, peak aortic jet velocity (greater than 5 m/s) and LVEF (less than 60%) were associated with all-cause and cardiovascular mortality without AVR; these factors were also associated with postprocedural mortality in those patients with severe AS at baseline who underwent AVR (surgical AVR in 310 patients; transcatheter AVR in 78 patients).

“These findings provide support for consideration of early elective AVR in these patients. Closer and more frequent (every 6 to 12 months) clinical and echocardiographic follow-up might be implemented in patients with moderate AS and a peak aortic jet velocity of 3.0 m/s or greater or LVEF less than 60%,” Lancellotti’s group suggested. “The findings from this international patient database generally confirm the low incidence of sudden cardiac death among asymptomatic patients with AS and recapitulate the observations made in previously reported natural history studies. However, of importance are the observations that among asymptomatic patients with severe AS, a baseline peak jet velocity at least 5 m/s or a left ventricular ejection fraction less than 60% was associated with an increased risk of all-cause and cardiovascular mortality even following AVR. If validated in other studies, these observations could influence decision making and the timing of surgical referral,” agreed Patrick O’Gara, MD, of Brigham and Women’s Hospital in Boston, and Robert Bonow, MD, of Chicago’s Northwestern Medicine, in an editor’s note accompanying the paper.

However, as the authors acknowledge, there are limitations to their analysis that could serve as a stimulus to improve both data collection and patient management. Limitations of their study included that 22% of eligible patients from their registry didn’t have enough information to make it into the analysis. Additionally, asymptomatic status was not confirmed with exercise testing in all cases. They state, “However, our data highlight the need for additional efforts with probably closer follow-up in these patients, since the occurrence of overt heart failure remains a significant problem even in heart valve centers of excellence.”