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Cardiac·CA-2

CABG & MVR: Acute HF

Quadruple CABG and MVR in a morbidly obese patient with recent MI and IABP support.

The stem

A 52 y.o., 130 kg man is scheduled for quadruple coronary artery bypass grafting and mitral valve replacement. HPI: Patient suffered an acute MI complicated by chronic heart failure and post-infarct mitral insufficiency 5 days ago. Cardiac function is supported by dobutamine and IABP...

Focus

Management of acute MR, low ejection fraction (30%), and the risks of morbid obesity.

Examination relevance

Expect probing questions on induction choice and IABP management. Valvular lesions appear in nearly every examination cycle.

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Expert sample response

This patient is in cardiogenic shock with acute mitral regurgitation (MR) and is hemodynamically fragile despite IABP and dobutamine. My anesthetic goals are to maintain forward flow by avoiding bradycardia and managing afterload, essentially following the 'fast, forward, and full' principle of MR management.

For induction, I will use an etomidate or high-dose opioid technique to minimize myocardial depression. I will have emergency vasoactive medications (epinephrine, norepinephrine) primed and ready. I must be extremely cautious with positive pressure ventilation, as it can decrease venous return and further exacerbate low cardiac output in a heart dependent on preload. Intraoperative TEE is mandatory to assess the repair and manage the ongoing heart failure. I will maintain IABP throughout the induction and procedure until weaning from bypass is confirmed successful.

Full walkthrough

What the Examiner Is Testing

This case tests your understanding of the hemodynamic goals for acute MR — specifically the "fast, forward, and full" principle — and whether you can manage induction in a patient who is already in cardiogenic shock on two mechanical supports. The examiner wants to hear you articulate why each drug choice either helps or hurts forward flow.

The Board Trap

The trap is using a standard induction dose of propofol. Propofol causes vasodilation and myocardial depression — in a patient with EF 30% on dobutamine and an IABP, that's enough to cause cardiovascular collapse on the table. The second trap is forgetting to maintain the IABP through induction.

Walk-Through: How This Case Plays Out

Examiner: The patient is on dobutamine and IABP. How do you induce anesthesia?

Me: I would use a high-dose opioid technique — fentanyl 5-10 mcg/kg as the primary induction agent, supplemented with a low-dose benzodiazepine for amnesia. I'd consider etomidate if I need a hypnotic. The goal is to minimize myocardial depression. I will not use propofol as a primary agent here — too much vasodilation in an already compromised ventricle. I want epinephrine and norepinephrine drawn up and ready before I give anything.

Examiner: You've induced. On laryngoscopy, his BP drops to 65/40. What do you do?

Me: I would push epinephrine — small boluses, 10-20 mcg, to restore the MAP quickly. I'd check IABP timing and make sure it's augmenting properly. I'd give a fluid bolus, 250-500 mL of balanced crystalloid, just to make sure preload is adequate. This patient's heart depends on preload — I don't want to be underfilled going into sternotomy.

Examiner: Cardiopulmonary bypass is weaning. The heart won't come off. What's your next step?

Me: My plan is to communicate immediately with the surgeon and perfusionist. I'd optimize the inotropic support — increase dobutamine, consider milrinone if the PVR is elevated. If the heart still won't come off, we're talking about an intra-aortic balloon pump optimization, and the surgeon may be considering a ventricular assist device. I'd have TEE up to assess volume status and wall motion to help guide the decision.

Examiner: TEE shows severe RV dysfunction after bypass. What do you do?

Me: I would add inhaled nitric oxide to reduce RV afterload — 20 ppm to start. I'd avoid anything that increases PVR: hypoxia, hypercarbia, acidosis, high PEEP. Vasopressin can help maintain systemic perfusion without worsening pulmonary hypertension. If the RV is failing badly, we need to consider going back on bypass and reassessing.

Key Phrases That Score Points

  • "Fast, forward, and full — I want to maintain forward flow by keeping SVR appropriate and avoiding bradycardia."
  • "Epinephrine drawn up before induction — in a patient with EF 30%, I'm not waiting to scramble for it."
  • "IABP stays in through induction and until we're on bypass — I don't pull it early."
  • "TEE is mandatory here — I need to see what the heart is doing, not just guess from numbers."
  • "Inhaled nitric oxide for acute RV failure post-bypass — it's selective pulmonary vasodilation without dropping systemic SVR."

Why This Case Appears on the Boards

Valvular lesions appear on nearly every examination cycle. This case specifically tests whether you understand MR hemodynamics — not just the mnemonic, but why bradycardia is bad (increased regurgitant fraction), why SVR matters, and why TEE guides every decision on the cardiac table.