每日一题_2022.07.05

An 83-year-old man with severe aortic stenosis, chronic obstructive pulmonary disease, and coronary artery disease, who is status post coronary artery bypass graft, hypertension, and hyperlipidemia, is admitted to the ICU hemodynamically stable and comfortable after a transcatheter aortic valve replacement via a transfemoral approach using a balloon expandable valve. Sixty minutes after ICU admission, his vital signs have acutely changed: temperature is 37.9°C (100.2°F), blood pressure 82/50 mm Hg, heart rate 145 beats/min, oxygen saturation 90% on nonrebreather face mask. He is awake and denies chest pain. Physical examination demonstrates clear lungs bilaterally, regular tachycardia, low-pitched early diastolic murmur, and a soft S1 sound. His jugular venous pulsation is visible 5 cm above the sternal notch and refills slowly after occlusion. His extremities are cold, and he has thready pulses at the radial, dorsalis pedis, and posterior tibial arteries. 

Which of the following is the most likely etiology for his change in physiology?

A. Pericardial tamponade 

B. Acute mitral insufficiency 

C. Acute aortic insufficiency 

D. Aortic dissection

答案解析：

急性主动脉瓣关闭不全，无论是瓣周的还是中央的，都是经导管主动脉瓣置换术 (TAVR) 的已知并发症，据报道发生率高达70%。急性主动脉瓣返流导致收缩期左心室 (LV) 突然容量超负荷。因此，LV收缩末期容积高于正常，在随后的舒张期，左心房和 LV 之间的压力梯度降低较早。这导致早期二尖瓣关闭，可闻及软 S1 音。由于 LV 的心室-动脉梯度变化，观察到早期收缩甚至舒张二尖瓣返流。这导致 LV 每搏输出量减少和反射性心动过速。因此，患者常有脉搏细弱和四肢冰冷。

TAVR 术后曾观察到心包填塞，但较为罕见。此外，据报告，患者的颈静脉搏动在胸骨角上方 5 cm 处，再充盈缓慢，与填塞不一致。败血症与心动过速和低血压相关，但通常与四肢冰冷和体温正常无关。在 TAVR 术后报告了急性三度心脏传导阻滞，但通常与心率过快无关。房室传导完全丧失可引起心输出量下降和低血压，但通常心输出量减少的原因是心动过缓，而不是每搏输出量减少。此外，通常不会观察到舒张期杂音。升主动脉夹层是一种罕见但已知的并发症，肯定比主动脉瓣关闭不全少见。但这应伴有冠状动脉缺血。与急性二尖瓣反流相关的典型杂音是高调、吹风样全收缩期杂音。

正确答案：C

补充内容：

体征

1.视诊 心尖搏动向左下移位。部分重度关闭不全者颈动脉搏动明显,并可有随心搏出现的点头运动( De Musset 征)。可见毛细血管搏动。

2.触诊 心尖搏动移向左 下,呈抬举样搏动。有水冲脉。

3.叩诊 心界向左下增大而心腰不大,因而心浊音界轮廓似靴形。

4.听诊 主动脉瓣第二听诊区可闻及叹气样、递减型、舒张期杂音,向胸骨左下方和心尖区传导,以前倾坐位最易听清。重度反流者,有相对性二尖瓣狭窄心尖区出现柔和、低调、递减型舒张中、晚期隆隆样杂音(AustinFlint杂音),系主动脉瓣关闭不全时回流血液限制二尖瓣开放所致。周围大血管可听到枪击声和Durozierz双重杂音。