Off-pump coronary artery bypass grafting
Stem
A 71-year-old man, 84 kg, with three-vessel disease (LAD, obtuse marginal and right coronary), ejection fraction 45%, severe COPD and stage 3 chronic kidney disease is scheduled for coronary bypass. The surgeon plans an off-pump operation to avoid cardiopulmonary bypass. He has a radial arterial line and a pulmonary artery catheter, and the TEE probe is in.
Question
How do you manage the case, especially while the lateral and posterior vessels are grafted?
Ideal answer
HeadlineA beating-heart operation where I trade bypass for instability during heart displacement: I keep him full and perfused, watch for ischemia, and keep the pump ready.
- Perfusionist in the room, circuit ready, because unplanned conversion carries much higher mortality.1
- Heparin to an ACT above about 350–400 seconds, with a full bypass dose ready if we convert; centers differ.2,3
- Head down, volume, phenylephrine as displacement starts, because a full heart tolerates manipulation and pressure drops with lifting.3,2
- Raise MAP during each coronary occlusion, and ask for an intracoronary shunt if ischemia becomes intolerable.3
- Call conversion early, not as a crash, for persistent hypotension, ST change or ventricular arrhythmia.2
Watch for: falling pressure, ST change, new regional wall motion abnormality or mitral regurgitation on TEE, and ventricular ectopy.
Breaking down the answer
- What the evidence says — CORONARY randomized 4752 patients: 30-day hard outcomes did not differ; off-pump cut transfusion but increased early repeat revascularization.4 At 5 years the composite was 23.1% versus 23.6%.5 Changes if: a calcified aorta, which favors avoiding cannulation.
- Why pressure falls — lifting the apex compresses right-sided inflow; repositioning to let the right heart fill sometimes fixes it.3 Obtuse marginal targets need steep Trendelenburg with the left side up.2
- Which graft hurts most — grafts to less-diseased vessels cause more instability than grafts to occluded ones,3 because there are no collaterals behind them.
- Monitoring — TEE and a pulmonary artery catheter in every patient in one program;2 TEE views degrade once the heart is verticalized, so trends on the catheter and ECG matter.
- Side clamp — systolic pressure held around 110 mmHg for proximal anastomoses,2 to limit aortic injury.
- Arrhythmia and reversal — amiodarone 150 mg for ventricular dysrhythmias, then 1 mg/min; a small protamine dose, 50–100 mg, at the end.3
Follow-up question
During the obtuse marginal anastomosis, with the heart verticalized, the pressure drops to 68/40, pulmonary artery pressure rises from 34/16 to 52/30, runs of ventricular tachycardia appear, and phenylephrine is not helping. What do you do?
Follow-up answer
HeadlineIschemia with acute ventricular dysfunction, likely with mitral regurgitation from displacement; I tell the surgeon to put the heart back now.
The heart returns to the pericardium and the stabilizer comes off while I give volume and an inotrope such as epinephrine, and amiodarone 150 mg for the ventricular tachycardia.3 I top up heparin to the bypass dose so the pump can start, and ask the surgeon for a shunt. If it recurs, we convert electively now rather than in arrest.2 In 2742 planned off-pump cases, 3.4% converted, with mortality 11.7% versus 1.3%.1
Pitfalls that cost points
- Drawing arterial blood or chasing the line during a posterior anastomosis; the surgeon needs a still, stable field.2
- Assuming off-pump means less vigilance for heparin-induced thrombocytopenia or bleeding; full anticoagulation is still given.
- Letting the patient cool; without a heat exchanger, warming is my job.
Rapid-fire
Q: Who converts most often? A: In one series female sex and ejection fraction of 35% or less predicted conversion, and less anesthetist off-pump experience was an independent risk.1
Q: Reported conversion rates? A: 1.4–16% across studies; 5.5% in a 196,576-patient STS analysis.1
Q: First vasopressor for anastomosis hypotension? A: Phenylephrine, with volume management.2
Q: Did off-pump reduce 5-year events? A: No: composite 23.1% versus 23.6%, and repeat revascularization 2.8% versus 2.3%.5
Numbers to know
| Item | Value |
|---|---|
| ACT for off-pump CABG | > 350 s (one program) to > 400 s (MGH)2,3 |
| Systolic pressure for side clamp | About 110 mmHg2 |
| CORONARY 30-day composite | 9.8% vs 10.3%4 |
| Transfusion off vs on pump | 50.7% vs 63.3%4 |
| Unplanned conversion / mortality | 3.4% / 11.7% vs 1.3%1 |
| Amiodarone | 150 mg IV, then 1 mg/min3 |
Links
Sources
- 1.Conversion from off-pump to on-pump coronary artery bypass grafting: impact of surgeon and anaesthetist experience · Interdiscip Cardiovasc Thorac Surg (PMC10751234), 2023 · pmc.ncbi.nlm.nih.gov
- 2.Current trend of off-pump coronary artery bypass grafting (book chapter, Front Lines of Thoracic Surgery, InTech) · InTech (open access), 2012 · core.ac.ukSurgical-team chapter: TEE and PA catheter in all patients; Trendelenburg and left-side-up for posterior targets; phenylephrine first; ACT above 350 s; conversion triggers; SBP 110 mmHg for the side clamp.
- 3.Anesthesia for Cardiac Surgery: Other Cardiac Procedures (Clinical Anesthesia Procedures of the Massachusetts General Hospital) · MGH / Wolters Kluwer (Anesthesia Central) · anesth.unboundmedicine.comOnly the freely visible part of the off-bypass CABG section was read: ACT above 400 s, protamine 50-100 mg, volume, MAP, shunts, amiodarone 150 mg.
- 4.Off-pump or on-pump coronary-artery bypass grafting at 30 days (CORONARY) · N Engl J Med (abstract), 2012 · europepmc.org
- 5.Five-year outcomes after off-pump or on-pump coronary-artery bypass grafting (CORONARY) · N Engl J Med (abstract), 2016 · europepmc.org
Facts on this page were checked against these sources on Nov 2, 2026. Guidelines change; confirm doses against current institutional protocols.