2022 SCAI SHOCK

Title:
Cardiogenic Shock with Dynamic Mitral Regurgitation Requiring Mechanical Circulatory Support

Introduction:
Cardiogenic shock and acute myocardial infarction is often secondary to LV failure but can rarely present in a delayed manner due to mechanical complications such as papillary muscle rupture, mitral regurgitation, ventricular septal defect and free wall rupture. We present case of cardiogenic shock secondary to severe mitral regurgitation requiring multiple mechanical circulatory support devices for optimal management.

Clinical Case:
A 79-year-old female with prior history of anemia, hyperlipidemia, hypertension, carotid artery stenosis and atrial fibrillation presented with substernal chest discomfort. Physical examination reveals stable hemodynamics with tachycardia (141 bpm). Her electrocardiogram demonstrated anterior ST segment elevations and reciprocal inferolateral depressions. Laboratory work revealed leukocytosis and troponin elevation. She underwent emergent coronary angiography that demonstrated a mid-left anterior descending artery occlusion for which primary cutaneous coronary intervention was performed with good results. Her left ventriculogram demonstrated anteroapical regional wall motion abnormality with a calculated ejection fraction of 35-40%. Post procedure, the patient developed expressive aphasia and left temporal lobe ischemic cerebrovascular accident. She was treated with anticoagulation, rate control and dual antiplatelet therapy for her acute coronary syndrome and acute ischemic stroke.

Post procedurally, in the cardiac intensive care unit, the patient persistently hypotensive and hypoperfusing (lactic acid 7.1 mmol/L). She was started on norepinephrine infusion and an emergent echocardiogram demonstrated severe functional mitral regurgitation without evidence of ischemic leaflet tethering. She underwent a right heart catheterization that demonstrated a severely depressed cardiac output (1.5 L/min) and poor forward flow secondary to mitral regurgitation. Due to this, an intra-aortic balloon pump was placed which aided in successful restoration of perfusion. She was treated aggressively with intravenous diuretics, inotropes, afterload reduction with the intra-aortic balloon pump and rate control for atrial fibrillation. However, she subsequently continued to have low urine output and therefore decision was made to transition her to percutaneous left ventricular assist device support. She was cardioverted with transesophageal echocardiographic guidance. She continued to have improvement in her mental function and renal status.

Given her improving hemodynamics, the Impella was gradually weaned and decannulated. She continued to do well for a few days but due to repeated episodes of atrial fibrillation with rapid ventricular response, developed renal and mental status instability. Due to her advanced age and multiorgan involvement, the patient was treated conservatively and was subsequently transition to hospice care.

Discussion:
SCAI stage B cardiogenic shock constitutes at challenging clinical entity that can rapidly evolve into higher stages. Though LV failure from acute myocardial infarction still constitutes the chief etiology in this scenario, alternate etiologies such as functional or ischemic mitral regurgitation, ventricular septal defect and papillary muscle rupture should be entertained in patients who develop cardiogenic shock in a delayed manner. Though the intra-aortic balloon pump is very effective in patients with mitral regurgitation, these patients might often require escalation to higher mechanical circulatory support devices to achieve optimal diuresis and pulmonary decongestion goals.