Successful MitraClip XTR for Torrential Mitral Regurgitation Secondary to Papillary Muscle Rupture as a Complication of Acute Myocardial Infarction

A 70-year-old male with a past medical history of hypertension presented to an outside hospital emergency room complaining of constant chest pain and worsening shortness of breath for a week. The systolic blood pressure was 85/45 mm Hg, heart rate 140 beats/minute, and oxygen saturation was 89%. Physical examination was remarkable for a 4/6 systolic murmur at cardiac apex, and pulmonary rales on all lung fields. His electrocardiogram showed T wave inversion in leads V2-V4 and troponin level was elevated at 8.1 ng/dl with a creatinine of 3.5 mg/dl. Chest X-ray showed flash pulmonary edema. He was started on maximal dose of two vasopressors, unfractionated heparin, aspirin, and a high dose statin. The patient was then transferred to our hospital for cardiogenic shock (CS) management. An emergent bedside echocardiogram showed an ejection fraction of 60%, flail posterior valve leaflet, and severe eccentric mitral regurgitation (MR). A right heart catheterization revealed a pulmonary artery wedge pressure of 22 mm Hg with giant V waves 60 mmHg; cardiac output 3.7 L/min, and cardiac index 1.8 L/min/m. Given the refractory CS and hypoxia, emergent endotracheal intubation was performed and mechanical circulatory support (MCS) with Impella CP (Abiomed, Danvers, MA) was initiated providing 3.5 l/min flow. Coronary angiography showed obstructive coronary artery disease involving the proximal and mid-circumflex. Cardiac surgery was consulted emergently but deemed this patient’s surgical risk to be extremely high (Society of Thoracic Surgeons score of 14.3%), and it was decided to perform percutaneous coronary intervention (PCI) with a drug eluting stent (Figure 1a–b and Movie I-II in the Data Supplement). Transesophageal echocardiogram (TEE) showed torrential MR secondary to papillary muscle rupture (PMR) and flail posterior leaflet. (Figure 1c–d and Movie III-IV in the Data Supplement). Following the Impella CP placement, the vasopressor requirements were weaned off and the patient was started on an afterload reduction with nitroprusside. Despite prompt revascularization and hemodynamic support, pulmonary edema and hypoxia were refractory and it became difficult to oxygenate the patient without higher concentration of FiO2 (100%) and high positive end-expiratory pressure. After discussion in a multidisciplinary meeting, we decided to perform a transcatheter mitral valve repair (TMVr) with MitraClip XTR system (Abbott Vascular, Santa Clara, CA). Due to concerns that the MitraClip system would interact with the Impella device during the MitralClip deployment, the Impella CP was exchanged for an intra-aortic balloon pump (IABP) to maintain hemodynamic support. The clip was successfully deployed at our first attempt between P2 and A2. Real-time three-dimensional TEE showed adequate grasping of the flail segment and significant reduction of MR grade to trivial, with 1 mmHg residual gradient (Figure 1f–g and Movie V-VI in the Data Supplement). Post-procedural measurements showed a mean left atrial pressure of 10 mmHg, v-wave of 12 mmHg, cardiac output of 4.9 L/min, and cardiac index of 2.8 L/min/ m. There was a small residual iatrogenic atrial septal defect (iASD) measuring 3 × 4 mm with left to right shunt; the decision was made to observe the iASD clinically with a follow-up echocardiogram. IABP was removed during the index procedure. He was discharged 3 days later with complete recovery. At 6-month follow-up, the patient remained asymptomatic in New York Heart Association Class I, and echocardiography revealed trace residual MR with no evident iASD.