Low-Flow, Low-Gradient Aortic Stenosis With a Coronary Lesion
79-year-old man with known severe aortic stenosis presents with progressive dyspnea on exertion and one episode of syncope while climbing stairs. BP 118/70, HR 76, soft S2, grade 3/6 late-peaking systolic murmur. LVEF is 30%. Aortic valve area is 0.7 cm², mean gradient 25 mmHg, peak velocity 3.5 m/s at rest. Dobutamine stress echocardiography increases stroke volume by 20%, mean gradient to 40 mmHg, and LVEF to 40%; aortic valve area remains 0.8 cm²; no wall motion abnormality. Coronary angiography shows a 60% mid-LAD lesion. STS score is 6%, frailty assessment is favorable, and he has no significant lung disease.
1. How do you interpret the resting and dobutamine echocardiographic findings? Does he have true severe aortic stenosis?
Read the worked answer
Resting findings show low-flow, low-gradient severe AS with reduced EF: AVA 0.7 cm², mean gradient 25 mmHg, LVEF 30%. The low gradient could reflect either true severe AS with a failing ventricle or pseudo-severe AS, in which the valve appears small because flow is low.
Dobutamine echo demonstrates contractile reserve (stroke volume rises 20%, EF improves to 40%) and the mean gradient rises to 40 mmHg while AVA remains 0.8 cm². In pseudo-severe AS, AVA typically increases to >1.0 cm² as flow increases, and the gradient does not rise substantially. Because AVA remains <1.0 cm² and the gradient rises, this is consistent with true severe AS. The absence of wall motion abnormality argues against a large area of nonviable myocardium. The judgment is that his symptoms and syncope are attributable to AS, and he is not merely a low-flow state from cardiomyopathy.
2. What treatment strategy do you recommend, and how do you manage the concomitant LAD disease?
Read the worked answer
He has symptomatic severe AS with LV dysfunction and contractile reserve, so aortic valve replacement is indicated; medical therapy alone has a poor prognosis. The choice between TAVR and SAVR should be made by the heart team. At age 79 with an STS score of 6% and favorable frailty, both are reasonable; TAVR is often preferred for intermediate-risk older patients, while SAVR is reasonable if he has anatomy unfavorable for TAVR or wants a durable valve.
The 60% mid-LAD lesion is not flow-limiting by angiography alone. Do not perform PCI routinely for a 60% lesion without evidence of ischemia or angina; if PCI is considered, it can be done before TAVR, but unnecessary stenting adds bleeding and antiplatelet risk. Assess symptoms, myocardial ischemia if unclear, and coronary anatomy at the time of valve replacement. Manage heart failure medically while awaiting AVR.