Rapid Review·Cardiovascular
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Cardiothoracic Surgery
T1Must knowCoronary Artery Bypass Grafting
Focus on
Bypass wins over stents for left main disease, three-vessel disease, and multivessel disease with the proximal LAD in a diabetic or a patient with reduced EF. The internal mammary artery graft to the LAD is the one that lasts; vein grafts fail over a decade. Afterwards: atrial fibrillation, mediastinitis, post-cardiac injury syndrome, and lifelong secondary prevention.
Key takeaways
Technique and indications
Arterial conduit
autologous conduits are anastomosed distal to the coronary stenosis; the internal mammary artery has better patency and prognosis (the left one goes to the left anterior descending artery).Venous conduit
the great saphenous vein supplies reversed segments from the aorta to the other targets (50 to 60 percent patent at 10 years).Approach
through a median sternotomy, on cardiopulmonary bypass with cardioplegic arrest, or off-pump on a beating heart.Indications
four classic ones.- Left main stenosis.
- Significant proximal left anterior descending stenosis (over 70 percent) with 2- or 3-vessel disease.
- Symptomatic 2- or 3-vessel disease (especially with diabetes or a reduced ejection fraction).
- Disabling angina despite maximal medical therapy.
Other indications
failed or unsuitable percutaneous intervention, and mechanical complications of infarction needing surgery.- A heart team weighs anatomic complexity against surgical risk.
| Bypass surgery | Percutaneous intervention | |
|---|---|---|
| Best for | Left main, three-vessel, diabetic multivessel, low ejection fraction, complex anatomy | One- or two-vessel disease, acute coronary syndrome culprit lesions, high surgical risk |
| Advantage | Fewer repeat revascularizations; survival benefit in the groups above | Less invasive, faster recovery |
| Downside | Stroke, mediastinitis, longer recovery, vein-graft attrition | Restenosis, stent thrombosis, dual antiplatelet therapy, more repeat procedures |
| Antiplatelet after | Aspirin for life | Dual antiplatelet therapy 6 to 12 months, then aspirin |
Preoperative preparation
Imaging
angiography for targets, echocardiography for function and valves, carotid duplex with a bruit or prior stroke.Drugs
hold clopidogrel or ticagrelor 5 days (prasugrel 7) and warfarin; continue aspirin.Optimize
glucose control, smoking cessation, treat dental infection.What goes wrong after a sternotomy
| Timing | Complication | Clue | Response |
|---|---|---|---|
| Hours | Bleeding, tamponade from a localized clot | Rising chest-tube output; shock with equalized filling pressures | Re-exploration |
| Hours to days | Low output or vasoplegia after bypass | Hypotension, low cardiac index | Inotropes, vasopressors, balloon pump |
| Days 2 to 4 | Atrial fibrillation (30 to 40 percent) | Irregular tachycardia | Beta blocker or amiodarone; anticoagulate if over 48 hours; most convert within 6 weeks |
| Days | Perioperative infarction (graft occlusion), heart block, stroke, kidney injury, atelectasis and pleural effusions, phrenic nerve injury | New ST changes, troponin far above the expected post-operative rise | Angiography; pacing; supportive care |
| Days to weeks | Sternal dehiscence and mediastinitis | Sternal click, drainage, fever | Rewiring, debridement, antibiotics (Sternal Dehiscence & Mediastinitis) |
| Weeks to months | Post-cardiac injury syndrome | Fever, pleuritic pain, rub, effusion | Non-steroidal anti-inflammatory drug plus colchicine (Post-Cardiac Injury Syndrome) |
| Years | Graft failure | Recurrent angina | Angiography; percutaneous intervention of the native vessel or graft, or redo surgery |
After discharge
Secondary prevention for life
aspirin indefinitely, a high-intensity statin, a beta blocker (at least a year), an angiotensin-converting-enzyme inhibitor for diabetes, hypertension, kidney disease or a low ejection fraction, smoking cessation.Cardiac rehabilitation
reduces mortality and readmission.Sternal precautions
for 6 to 8 weeks.Coronary-subclavian steal
a left subclavian stenosis proximal to the mammary graft causes angina with arm exercise (Subclavian Steal Syndrome).Three days after bypass surgery, a patient develops an irregular tachycardia at 130 with no P waves. What is the complication, how common is it, and how is it treated?
Post-operative atrial fibrillation, in 30 to 40 percent of patients on days 2 to 4. Control the rate with a beta blocker or amiodarone, anticoagulate if it lasts over 48 hours; most convert within 6 weeks.
How it's tested
A 62-year-old diabetic with angina and angiography showing 70% proximal LAD, 80% circumflex and 90% RCA stenoses, EF 40%: three-vessel disease with diabetes and reduced EF — CABG, not multivessel PCI.
Which graft lasts and why it matters: the left internal mammary artery to the LAD — ~90% patency at 10 years and the driver of the survival benefit; saphenous vein grafts fail progressively.
Day 3 after CABG, heart rate 140 and irregular: post-operative atrial fibrillation — beta blocker or amiodarone; anticoagulate if it lasts beyond 48 hours; expect resolution.
Angina recurs 12 years after CABG: vein-graft atherosclerosis — angiography; PCI of the graft or native vessel.
Chest pain when using the left arm in a patient with a LIMA graft: coronary-subclavian steal from a proximal left subclavian stenosis — angiography and stenting.
Day 2 after CABG, an irregular tachycardia at 130: post-operative atrial fibrillation — rate control with a beta blocker (or amiodarone), anticoagulation if it persists beyond 48 hours; it usually resolves within weeks.
Six hours after valve surgery: hypotension, rising CVP, falling chest-tube output that had been brisk, equalized filling pressures: tamponade from a clot — surgical re-exploration; echo may not show a circumferential effusion.
Three weeks after CABG: fever, pleuritic chest pain, a friction rub and a small effusion: post-cardiac injury syndrome — NSAIDs and colchicine.
Ten days after sternotomy the sternum clicks with coughing and the wound drains: sternal dehiscence — imaging for mediastinitis, rewiring.
Go deeper
Guidelines: 2021 ACC/AHA/SCAI Coronary Revascularization Guideline
Related Step 2 pages: Coronary Artery Bypass Grafting, Stable Angina, Acute Coronary Syndrome, Post-Cardiac Injury Syndrome, Sternal Dehiscence & Mediastinitis
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