Ogunleye Olushola O, Dalal Hussain, Mahmood Khalid, Neragi-Miandoab Siyamek, Campo Aarti
Department of Internal Medicine, Vassar Brothers Medical Center, Poughkeepsie, USA.
Department of Surgery, State University of New York (SUNY) Downstate Medical Center, Brooklyn, USA.
Cureus. 2022 Mar 13;14(3):e23114. doi: 10.7759/cureus.23114. eCollection 2022 Mar.
Systolic anterior motion (SAM) is the dynamic displacement of mitral valve leaflets anteriorly toward the left ventricular outflow tract (LVOT) during systole. SAM-like physiology has been reported to occur shortly after mitral valve replacement (MVR) surgery; occurrence beyond two years after surgery is very rare. A 55-year-old woman who had bioprosthetic MVR eight years earlier for non-rheumatic mitral stenosis presented to the emergency room with progressive dyspnea and sudden-onset chest pressure. Physical examination noted a grade 3/6 systolic murmur at the cardiac apex, a soft diastolic murmur at the left sternal border, and diffuse expiratory wheezing. B-type natriuretic peptide (BNP) was elevated (286 pg/mL). Transthoracic echocardiography (TTE) showed mitral regurgitation and severe aortic insufficiency; the mitral prosthesis was protruding into the LVOT, causing LVOT obstruction with a peak gradient of 16.3 mmHg and peak velocity of 2.0 m/s. Transesophageal echocardiography (TEE) confirmed severe bioprosthetic MV dysfunction, severe aortic regurgitation, and SAM-like physiology. Left cardiac catheterization showed normal coronaries. She underwent repeat MVR and aortic valve replacement. She was started on daily aspirin and warfarin post-operatively, then discharged home on post-operative day 10. During post-operative office visits, she reported no complications. SAM-like physiology was absent in a two-month follow-up TTE, with reduced LVOT peak gradient of 6.5 mmHg and peak velocity of 1.3 m/s. Dynamic SAM-induced LVOT obstruction could be asymptomatic or result in severe heart failure with 20% risk of sudden cardiac death. SAM may occur within days following MVR or may have a delayed presentation. Medical management, including beta-blockade, is the cornerstone of initial management, while structural damage to the prosthetic valve mandates repeating mitral valve replacement surgery. This case highlights the importance of long-term follow-up of patients after MVR to assess for SAM, which could occur with or without degenerative changes of the prosthetic valve.
收缩期前向运动（SAM）是指二尖瓣叶在收缩期向前朝向左心室流出道（LVOT）的动态移位。据报道，二尖瓣置换术（MVR）后不久会出现类似SAM的生理现象；术后两年以上出现这种情况非常罕见。一名55岁女性，8年前因非风湿性二尖瓣狭窄接受了生物瓣MVR，现因进行性呼吸困难和突发胸痛就诊于急诊室。体格检查发现心尖部有3/6级收缩期杂音，左胸骨缘有柔和的舒张期杂音，以及弥漫性呼气哮鸣音。B型利钠肽（BNP）升高（286 pg/mL）。经胸超声心动图（TTE）显示二尖瓣反流和严重主动脉瓣关闭不全；二尖瓣人工瓣膜凸入LVOT，导致LVOT梗阻，峰值压差为16.3 mmHg，峰值流速为2.0 m/s。经食管超声心动图（TEE）证实生物瓣二尖瓣严重功能障碍、严重主动脉瓣反流和类似SAM的生理现象。左心导管检查显示冠状动脉正常。她接受了再次MVR和主动脉瓣置换术。术后开始每日服用阿司匹林和华法林，术后第10天出院回家。在术后门诊随访期间，她报告无并发症。在术后两个月的TTE随访中，未出现类似SAM的生理现象，LVOT峰值压差降至6.5 mmHg，峰值流速降至1.3 m/s。动态SAM引起的LVOT梗阻可能无症状，也可能导致严重心力衰竭，有20%的心源性猝死风险。SAM可能在MVR后数天内出现，也可能延迟出现。包括β受体阻滞剂在内的药物治疗是初始治疗的基石，而人工瓣膜的结构损伤则需要再次进行二尖瓣置换手术。本病例强调了MVR术后患者长期随访以评估SAM的重要性，SAM可在人工瓣膜有无退行性改变的情况下发生。
