Although an infrequent event, acute PMI following cardiac surgery can rapidly evolve and become a potentially life-threatening complication, the writing group, led by Mario Gaudino, MD, PhD, with Weill Cornell Medicine in New York, points out.
Data show that the incidence of postoperative myocardial infarction after cardiac surgery ranges from 0.3% to 9.8% after isolated coronary artery bypass graft (CABG) surgery and 0.7% to 11.8% after concomitant valvular surgery. For isolated mitral valve surgery, incidence ranges from 1.7% to 2.2%.
Short-term mortality is elevated among patients with acute PMI, irrespective of the type of surgery. Reported mortality rates range from 5.1% to 24%; the evidence on long-term mortality has been mixed.
Graft-related factors are the most common cause of PMI after CABG, but other factors may contribute, including technical factors, competitive flow, suture entrapment or coronary artery distortion, as well as non–graft related factors.
Currently, there is no consensus definition of PMI. Elevations in cardiac biomarkers may not be reliable for diagnosis after surgery, and pain management regimens may mask symptoms of ischemia, the writing group notes.
Given the difficulty in diagnosis, it's important to maintain a "high index of suspicion for acute PMI in all patients undergoing cardiac surgery because timely diagnosis and treatment are key to a good clinical outcome," they write.
Delay in urgent angiography has been associated with higher mortality; thus, a low threshold for action is encouraged for patients with suspected acute PMI.
Indications for urgent angiography include new ECG changes, chest pain with ongoing signs of ischemia, cardiac imaging abnormalities, cardiac rhythm abnormalities, significant elevations in cardiac biomarkers, and low cardiac output syndrome despite postoperative pressor support.
Patients with acute PMI and low cardiac output syndrome may require mechanical support when first-line treatment fails.
The writing group says fast and effective reperfusion of the ischemic zone, which is generally achieved by percutaneous intervention and, less often, by repeat surgery, is the key to a good clinical outcome.
The statement was prepared by the volunteer writing group on behalf of the AHA Council on Cardiovascular Surgery and Anesthesia; Council on Clinical Cardiology; Council on Cardiovascular and Stroke Nursing; and Stroke Council.
https://www.medscape.com/viewarticle/993932
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