Impella 5.5 as a bridge-to-surgery in acute ischemic mitral regurgitation post-percutaneous coronary intervention: a case report

Abstract

Background: Acute ischemic mitral regurgitation (AIMR) is a significant complication of acute coronary syndrome that leads to severe and immediate hemodynamic deterioration and cardiogenic shock. Intra-aortic balloon pumps (IABP) are commonly used to support patients with AIMR as a bridge to surgery, though they may be insufficient in some cases.

Case presentation: A 74-year-old male presented with two days of indigestion and evident hypoxia, and an electrocardiogram revealed inferior and lateral ST-elevation myocardial infarction. Angiography demonstrated severe two-vessel coronary disease with a 100% thrombotic occlusion of the second obtuse marginal artery (OM2, culprit lesion) and an 80% stenosis of the proximal left anterior descending artery (LAD). Despite stenting of OM2, the patient remained hypoxic and hypotensive, necessitating escalated support via an IABP. A follow-up echocardiogram revealed severe mitral regurgitation presumed to be AIMR secondary to a ruptured posteromedial papillary muscle with a flail anterior leaflet (A2). Despite aggressive supportive measures with the IABP, the patient's hemodynamics continued to show cardiogenic shock and clinical status did not improve. However, the patient was required to abstain from surgery for a P2Y12 inhibitor therapy wash out period. Consequently, the IABP was upgraded to Impella 5.5 as bridge-to-surgery support on day 1 post-admission. Subsequently, the patient's hemodynamics improved, and he underwent a combined mitral valve replacement and coronary artery bypass grafting surgery on day 7 post-admission without incident. The Impella was successfully explanted on day 25 post-admission. Delay in explant was due to hypotension and respiratory status despite normalizing hemodynamics and echocardiogram revealing recovered left ventricular ejection fraction. The patient developed bacterial pneumonia and acute respiratory distress syndrome and expired on day 27 post-admission.

Conclusion: Although IABP is standard for supporting AIMR patients as a bridge to surgery, it may not provide sufficient hemodynamic support. This case supports a growing body of evidence that alternative forms of hemodynamic support should be considered if the traditional therapeutic modalities for AIMR do not adequately support patients. Clinicians may consider upgrading IABP to Impella to provide increased hemodynamic support and maintain AIMR patient stability while awaiting cardiac surgery.

Keywords: Acute coronary syndrome; Cardiogenic shock; Impella; Mitral regurgitation; Temporary mechanical circulatory support.

Fig. 1

12-lead ECG At Admission – Indicative of Lateral and Inferior STEMI. 12-lead ECG trace indicative of lateral and inferior STEMI, with ST elevation in the lateral (Green - I, V5-6) and inferior (Blue - II, III, aVF) leads

Fig. 2

LAD and OM2 Angiogram – Partial and Complete Stenoses. (A) Angiogram of the left anterior descending aorta (LAD) displaying 80% stenosis (white circle). (B) Angiogram of second obtuse marginal artery (OM2) displaying 100% stenosis (white circle)

Fig. 3

Pre-Operative Mitral Valve Assessment – AIMR due to A2 Leaflet Flail. (A) Two-dimensional (2D) transesophageal echocardiography showing an important flail of the anterior leaflet due to partial rupture of the posteromedial papillary muscle (Video S3). (B) 2D transesophageal color Doppler echocardiography showing severe mitral regurgitation. (Video S3). (C) 3D transesophageal echocardiography showing an important flail of the A2 scallop of the anterior leaflet (Video S4)