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A case of variant angina and myocardial infarction 6 months after successful bypass surgery
Insights
Discontinuing calcium antagonists after bypass surgery for variant angina can trigger myocardial infarction due to coronary artery spasm. Continuous calcium antagonist therapy is recommended post-surgery for these patients.
Area of Science:
- Cardiology
- Vascular Surgery
Background:
- Variant angina (Prinzmetal's angina) involves coronary artery spasm.
- Coronary artery bypass grafting (CABG) is a treatment for severe coronary artery disease.
- Calcium antagonists are used to manage vasospastic angina.
Observation:
- A 61-year-old man with variant angina underwent successful CABG for a 90% LAD stenosis.
- Post-surgery, the patient received continuous diltiazem (a calcium antagonist).
- Diltiazem was discontinued 6 months post-CABG due to hepatitis.
Findings:
- Within days of diltiazem discontinuation, the patient experienced an acute anterior myocardial infarction.
- Angiography confirmed a patent graft but revealed an anteroapical infarction.
- The infarction was attributed to severe, prolonged spasm of the left anterior descending artery (LAD).
Implications:
- This case highlights the critical role of continuous calcium antagonist therapy in preventing vasospasm post-CABG in variant angina patients.
- Abrupt cessation of calcium antagonists can precipitate myocardial infarction in susceptible individuals.
- Long-term calcium antagonist use should be considered in patients with variant angina undergoing CABG.
Abstract:
A 61-year-old man with variant angina underwent bypass surgery to the left anterior descending artery (LAD) which had a 90% narrowing in the proximal segment. The postoperative course was favorable, but 6 months after surgery, the calcium antagonist, diltiazem, with which the patient had been continuously treated since surgery, was stopped because of hepatitis. Immediately after discontinuation of the calcium antagonist, the patient had an acute anterior myocardial infarction. An angiogram demonstrated a patent graft and an anteroapical infarction. The infarction is thought to have been caused by a severe, prolonged spasm of the LAD distal to the graft or diffuse spasm of the LAD throughout its entire length. Thus, after bypass surgery calcium antagonists should be given continuously to patients with variant forms of angina pectoris.