Preliminary Study of Low-dose Dobutamine Stress Echocardiogram in Patients With Low-flow/Low-gradient Aortic Stenosis Combining Ventricular Dysfunction / 中国循环杂志

ABSTRACT

Objective: To explore the application value and safety of low-dose dobutamine stress echocardiogram (LDDSE) in patients of low-flow/low-gradient aortic stenosis combining left ventricular dysfunction with transcatheter aortic valve replacement (TAVR). Methods: A total of 5 eligible consecutive patients with contradiction of routine surgical valve replacement and going to receive TAVR in our hospital from 2013-10 to 2016-07 were enrolled. The mean aortic valvegradient, maximum flow velocity, each stroke volume and ejection fraction were recorded before and during LDDSE examination. The patients having confirmed diagnosis of true severe aortic stenosis with left ventricular contractile reserve received TAVR, for those without left ventricular contractile reserve received drug therapy or TAVR conditionally. The changes of cardiac function and NT-proBNP level were observed after TAVR. Results: All 5 patients showed positive finding in LDDSE; the mean aortic valve gradient ≥40mmHg and stroke volume≥20% implied that the patients had true severe aortic stenosis with left ventricular contractile reserve. No adverse reaction occurred during and after LDDSE. TAVR was performed in 4 patients and 1 was waiting for TAVR or balloon dilatation since temporary lacking of valve. The post-operative cardiac function was improved in all patients and NT-proBNP level was declined continuously. Conclusion: LDDSE examination could be considered in patients of aortic stenosis combining left ventricular dysfunction, low-flow and low-gradient to clarify ventricular contractile reserve and the severity of aortic stenosis. If the patients with ventricular contractile reserve, TAVR was recommended which was the effective treatment for relevant patients.