A 55-year-old man with known heart failure (EF 25%) is admitted to ICU with acute decompensated heart failure and cardiogenic shock. He is on noradrenaline 0.05 mcg/kg/min, dobutamine 7.5 mcg/kg/min, and an intra-aortic balloon pump (IABP). MAP is 55 mmHg, cardiac index 1.5 L/min/m2, PCWP 28 mmHg, lactate 5.5 mmol/L. Despite maximal medical therapy, he continues to deteriorate. The cardiothoracic team is consulted. What is the most appropriate next escalation?