Aortic valve replacement (AVR) — either surgical or transcatheter — remains the only treatment demonstrated to reduce mortality and morbidity in patients with aortic stenosis. Current guidelines from the American College of Cardiology/American Heart Association (ACC/AHA) are clear on the appropriateness of AVR in symptomatic patients, but management of asymptomatic cases is less definitive.
In the setting of asymptomatic severe aortic stenosis — defined as peak aortic jet velocity ≥ 4 m/s and mean pressure gradient ≥ 40 mm Hg — AVR is recommended by the ACC/AHA guidelines if any of the following apply:
Finally, the guidelines say that AVR may be considered in patients at high risk for rapid disease progression and at low surgical risk as well as in patients whose peak aortic jet velocity is rising by more than 0.3 m/s per year and who are at low surgical risk.
The new paper in Cleveland Clinic Journal of Medicine notes that assessment of asymptomatic aortic stenosis has relied on traditional echocardiographic measures of severity — namely, jet velocity, valve area, pressure gradient and LVEF.
While echo remains the best-established and most important initial tool in aortic stenosis assessment, its limitations figure into some of the gray areas in the ACC/AHA guidelines outlined above — as well as gray areas in similar European guidelines.
For instance, the paper cites the limitations of LVEF as a marker of left ventricular function, noting that it reflects change in ventricular cavity volume but not in the complex structure of the ventricle. “Several studies demonstrate that up to one-third of patients with severe aortic stenosis have considerable impairment of intrinsic myocardial systolic function despite a preserved ejection fraction,” notes Dr. Phelan.
In the context of this limitation, Dr. Phelan and his coauthors propose four additional variables for consideration in evaluating the effect of severe aortic stenosis on left ventricular function in the setting of a normal LVEF, none of which are included in current ACC/AHA guidelines:
After reviewing evidence in support of the incremental prognostic value of each of these variables in this setting, the authors envision a potential future revision to guidelines for asymptomatic aortic stenosis in which AVR may be considered if any of the following apply: