A 74-year-old Caucasian male presented to our institution via emergency medical services with two-days of indigestion. Upon arrival at our institution, the patient was noted to be hypoxic, hypotensive, with rales, and a 12-lead electrocardiogram demonstrated inferior and lateral STEMI (Fig. 1). Brain natriuretic peptide (BNP) level was 385 pg/ml, arterial lactic acid was 1.8 mmol/L, and troponin I level was severely elevated at 9338 ng/L (normal range 0–35 ng/L), confirming the STEMI diagnosis.

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

Upon notification, the catheterization laboratory conducted emergent coronary angiography. On angiography (Fig. 2 and Videos S1 and S2 in Supplementary Materials), the patient was noted to have severe two-vessel coronary disease with 80% stenosis of the proximal left anterior descending artery (LAD) (Fig. 2A) and a 100% thrombotic occlusion of the second obtuse marginal artery (OM2), which was the culprit lesion (Fig. 2B). The OM2 lesion was treated via percutaneous coronary intervention (PCI) with a 2.25 × 34 mm drug-eluting stent resolving with TIMI grade 3 flow. PCI of the LAD lesion was not considered as it was not thought to be contributing to LV dysfunction. The patient received an initial 180 mg bolus of P2Y12 inhibition ticagalor and twice daily doses of 90 mg thereafter.

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)

Following PCI, the patient remained hypoxic and required intubation with mechanical ventilation. Initial pulmonary edema was treated with intravenous nitroglycerin and diuretics and an IABP was placed. Soon after, however, he became hypotensive and vasopressor support with norepinephrine was necessary for hemodynamic support. Cardiac output was monitored with a Swan-Ganz catheter perioperatively. Fick’s cardiac index was 1.7 with a cardiac output of 3.7 L/min, a systemic vascular resistance of 1016 dynes/sec/cm2, a pulmonary capillary wedge pressure of 24 mmHg, and a central venous pressure of 15 mmHg, indicating that the patient remained in cardiogenic shock [2]. The inotrope dobutamine was added at 5 µg/kg/min.

Upon return to the ICU, an echocardiogram revealed severe mitral regurgitation (MR) secondary to a ruptured posteromedial papillary muscle with a flail anterior leaflet (A2) (Fig. 3 and Videos 3, 4, and 5 in Additional Materials). Given the absence of significant cardiac remodeling, the MR was presumed to be AIMR. Despite aggressive supportive measures with the IABP at an augmentation ratio of 1:1, inotropic and vasopressor support, the patient had a persistently low cardiac index of 1.7. Transcatheter edge-to-edge repair (TEER) was considered by the structural team. However given the patient’s status, it was not considered to be technically feasible, or likely to be successful. Instead, revascularization of the LAD along with mitral valve replacement was thought to be a better option in the long term, as the patient was diagnosed as diabetic during the current acute hospitalization.

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)

Given the patient’s last dose of P2Y12 inhibitor therapy was on day 1 post-admission after a cardiogenic shock alert, the cardiothoracic surgeon recommended abstaining from surgery until adequate time had passed. Consequently, the heart team chose to exchange the IABP for a surgically implanted Impella 5.5 (Abiomed, Danvers, MA) to provide bridging support and LV unloading during the P2Y12 wash out period. Prior to Impella implantation, the patient’s creatinine was 1.4 mg/dL, lactic acid had risen to 4 mmol/L, aspartate aminotransferase (AST) was 54 U/L, bilirubin was 1.4 mg/dL, LV ejection fraction (LVEF) was 55–60%, LV end diastolic diameter was 4.3 cm, and his MR grade was 4. The decision by the heart team to use Impella over venous-arterial extracorporeal membrane oxygenation (VA-ECMO) was based on the advanced age of the patient and enhanced risk of complications from VA-ECMO. Furthermore, stabilization of the respiratory component was achieved on mechanical ventilation and only the LV needed unloading. Impella 5.5 was chosen over CP as longer LV unloading support was anticipated and Impella CP is not designed for long-term support, just periprocedural.

Following the replacement of the IABP with the Impella 5.5, the patient’s hemodynamic indices stabilized, end organ perfusion improved, and the patient was taken off vasopressors. Combined mitral valve replacement/coronary artery bypass grafting (CABG) surgery occurred on day 7 post-admission without incident. The left internal mammary artery was used to bypass the LAD and the saphenous vein was used to bypass the right coronary artery (RCA) which was determined to be moderately and diffusely diseased.

Post-mitral valve replacement surgery, an echocardiogram revealed an LVEF of 50% and no significant valvular disease. The patient did not experience any stroke, limb ischemia, hemolysis, or access/vascular complications, although he did require one peripheral red blood cell transfusion of > 2 units. Unfortunately, the patient developed bacterial pneumonia that eventually led to acute respiratory distress syndrome. The patient needed continued support from the Impella postoperatively due to the patient’s unstable clinical status defined by respiratory oxygen requirements, need for ongoing vasopressors, and atrial fibrillation with rapid ventricular response. The Impella was successfully explanted on day 25 postadmission. Ultimately, the patient expired on day 27 post-admission due to respiratory complications from ARDS.