小剂量多巴酚丁胺负荷超声心动图在低流速低压差伴心功能不全的主动脉瓣狭窄患者中的初步应用分析

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

目的:探讨小剂量多巴酚丁胺负荷超声心动图(LDDSE)检查在主动脉瓣狭窄伴左心室功能不全、低流速低压差患者行经皮主动脉瓣置换术(TAVR)的应用价值和安全性。方法:2013-10至2016-07,在我院连续入选列为常规外科换瓣手术禁忌,且准备行TAVR适应证评估的重度主动脉瓣狭窄患者,同时合并严重左心室功能不全伴低流速低压差者,共纳入有效病例5例。记录LDDSE检查前、过程中的平均跨瓣压差、最大流速、每搏输出量、射血分数,对判定为真性重度主动脉瓣狭窄且具有左心收缩储备功能患者行TAVR治疗,无左心收缩储备功能者采取药物治疗或酌情行TAVR治疗。观察TAVR治疗后心功能和N末端B型利钠肽原(NT-pro BNP)变化。结果:5例患者均表现为LDDSE检查阳性,平均跨瓣压差均≥40mm Hg(1mm Hg=0.133k Pa),每搏输出量增加≥20%,提示患者为真性重度主动脉瓣狭窄且有心脏收缩储备功能。LDDSE过程中、结束后无明显不良反应。其中4例行经TAVR治疗,1例因暂无瓣膜等待TAVR或球囊扩张术。TAVR术后患者心功能逐渐好转或恢复至正常,NT-pro BNP持续下降。结论:低流速低压差且伴左心功能不全的重度主动脉瓣狭窄患者,可考虑行LDDSE检查明确心功能储备情况和主动脉瓣狭窄程度;如有心脏收缩功能储备,建议行TAVR治疗。TAVR是此类患者的有效治疗手段。

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.