What is the cardiac risk in this patient? What additional investigations should be performed?

What is the cardiac risk in this patient? What addi-tional investigations should be performed?

This patient is an elderly woman with known CAD, and a recent MI who is going for emergency surgery. There are several important factors that require consideration. The first of these is the post-MI course. If she has recurrent pain, CHF, or late ventricular dysrhythmias (>48 hours post-MI) she has a 15–30% risk of death or re-infarction in her first post-infarct year even without surgery.

Another issue is whether there was evidence of reperfu-sion following thrombolytic therapy. This would include pain relief, reperfusion dysrhythmias, large increases in creatine phosphokinase (CPK) enzyme levels, and an improvement in the ECG without evidence of MI. Anticoagulant therapy is of importance. Heparin therapy used for patients with recurrent chest pain would have to be stopped prior to surgery. Recent studies suggest that the timing may be very important. Patients whose heparin was stopped for more than 9.5 hours were more likely to develop recurrent ischemia requiring urgent intervention.

The majority of patients who have received throm-bolytic therapy have significant residual stenosis in vessels that have been reperfused, and they are often investigated with early cardiac catheterization, especially if they had a complicated infarction. Some centers treat patients who are doing well as they do any patient with a recent uncomplicated infarct, that is they perform a modified symptom-limited stress test prior to discharge (on post-MI day 5–7), and a symptom-limited stress test 6 weeks later.

The presence of sepsis is an important issue. The hemo-dynamic changes associated with sepsis may significantly stress the myocardium. These include an increased cardiac output because of endotoxin-induced vasodilation, and myocardial depression from myocardial depressant factor.

If the patient must have an urgent surgical procedure and no additional cardiac studies have been performed (e.g., stress test or angiogram), one should assume the patient has significant CAD. If time permits, a transthoracic echocardiogram (TEE), specifically assessing wall motion, LV ejection fraction, and mitral valve function would provide useful information.