🧵 10 HIGH-YIELD ICU PEARLS #002 Temporary Mechanical Circulatory Support in Cardiogenic Shock: I’ve seen patients die despite temporary Mechanical Circulatory Support (tMCS). I’ve seen others die from complications related to it. And I’ve seen several who, in my opinion, are alive today because of it. That has made me a believer in temporary MCS devices but deeply respectful of what happens when we get them wrong. The first rule: Define the shock phenotype before choosing the device. Don’t put the cart before the horse. 1️⃣ Phenotype first LV failure? RV failure? Bi-ventricular failure? Mechanical complication? Obstructive physiology? The “strongest” device isn’t necessarily the right one. PHENOTYPE → DEVICE Not the other way around. 2️⃣ Impella = direct LV unloading Impella moves blood: LV → ascending aorta It reduces LV filling while providing forward flow. The key concept isn’t simply: “More cardiac output.” It’s: "Unload the failing LV". 3️⃣ Think in pressure-volume loops As Impella support increases, the pump assumes more of the work of moving blood forward. The LV PV loop generally shifts leftward: ↓ LV filling pressure/volume ↓ native LV stroke work ↓ pressure-volume area ↓ wall stress A smaller native LV PV loop ≠ less systemic flow. The LV does less work because the pump is doing part of it. That’s LV unloading. 4️⃣ VA-ECMO is different VA-ECMO provides powerful circulatory + respiratory support. But peripheral VA-ECMO can bite you: ↑ LV afterload ↑ LV distension ↑ pulmonary congestion Hemodynamic support ≠ LV unloading. 5️⃣ More support ≠ better support Temporary MCS trades hemodynamic benefit for potential harm: Bleeding. Vascular injury. Hemolysis. Thrombosis. Device complications. And I may be missing some... The goal isn’t the biggest pump. It’s the right level of support for the shock phenotype. 6️⃣ Know DanGer Shock In selected patients with STEMI-related cardiogenic shock, Impella CP + standard care reduced 180-day mortality: 45.8% vs 58.5% (the number needed to treat was 8) But: ⚠️ Safety events: 24.0% vs 6.2% (the number needed to harm was 6) ⚠️ Renal replacement therapy: 41.9% vs 26.7% The lesson isn’t: “Impella saves lives.” It’s: Benefit comes with complications. Patient selection matters. A lot. 7️⃣ Don’t forget the RV An LV support device cannot directly support an isolated failing RV. Impella also needs adequate blood reaching the LV. Ask: Can the RV provide enough preload for effective LV support? Ignore the RV and you may choose the wrong device. 8️⃣ Find the lesion Think beyond “low EF.” Before initiating LV support, ask whether the underlying lesion or physiology makes unloading ineffective or potentially harmful. Find the lesion → understand the physiology → choose the support. Cardiogenic shock is a hemodynamic syndrome, not an EF diagnosis. 9️⃣ Timing matters Escalating vasoactives. Persistent hypoperfusion. Failure to clear lactate. Evolving end-organ dysfunction. Ask: “Is the support actually working?” A better cardiac index ≠ reversal of shock. If lactate isn’t clearing and end-organ dysfunction keeps worsening despite apparently adequate support, ongoing hypoperfusion may still be present. The transition from hemodynamic → hemometabolic shock is ominous and increasingly difficult to reverse. 🔟 Have an EXIT strategy Where are we going? Recovery? Bridge to decision? Durable LVAD Transplant? Another temporary support strategy? Temporary MCS should have a destination. If none is realistic, that matters before support is initiated. After years of watching temporary MCS succeed spectacularly -and fail miserably- my framework has become pretty simple: SHOCK → PHENOTYPE → DEVICE → EXIT STRATEGY Not: SHOCK → BIGGER PUMP #FOAMcc #FOAMed #MedEd