Case History

A 70 year old male has had stable angina pectoris since 1988. At that time, an exercise ECG revealed 14 MET capacity, peak heart rate 179, and 2 mm horizontal ST depression. On routine re-evaluation in 10/1996, he described angina pectoris every 2 weeks on Cardizem CD 180 mg q.d., Tenormin 50 mg q.d. and Pravachol.

An exercise-rest sestamibi study was performed using a 2-day protocol (See figures 1 and 2).

1.Describe the scintigraphic findings in detail. Include in your description, both the visual interpretation of the slice report and the quantitative polar map findings.

2.Categorize the scintigraphic findings into low, intermediate or high-risk for future coronary events.

The patient went on to have a coronary angiogram followed by successful coronary bypass graft surgery.

1.Elaborate the key factors which impact on the prognosis of patients with stable angina pectoris. In your discussion, describe the Duke angina score and its prognostication value.

2.What is the rationale for stress testing in patients with stable angina pectoris and a high likelihood of obstructive CAD? Which types of patients would you exclude from such testing?

3.Describe the Duke treadmill score. Discuss the strengths and weaknesses of this prognostic index for predicting cardiac mortality. To which subgroup of patients with chronic CAD might this index underestimate cardiac mortality risk? To which subgroups of patients might the index overestimate cardiac mortality risk?

4.What are the key prognostic variables which can be extracted from stress-redistribution thallium-201 myocardial scintigraphy? Include in your discussion (a) number of fixed defects, (b) number of reversible defects, (c) percent of myocardium on polar map display, (d) transient ischemic dilatation, (e) lung uptake. (f) Define high, intermediate and low risk thallium-201 stress redistribution.

5.What are the key prognostic variables which can be extracted from stress-rest sestamibi myocardial scintigrams. Include in your discussion (a) number of fixed defects, (b) number of reversible defects, (c) the summed stress score described by Berman and Harchamovitch. (d) Define high, intermediate and low risk stress-rest sestamibi myocardial scintigrams. Give approximate coronary event risk associated with each type of scan result.

6.Present the evidence that stress myocardial scintigraphy provides incremental prognostic information over clinical, stress ECG and angiographic variables in chronic CAD. In your answer, include the prognostic implications of a negative stress myocardial perfusion scintigram in the presence of angiographically proven disease.

7.Construct a cost-effective algorithm for test selection (stress ECG, stress myocardial scintigram and coronary angiogram) for patients presenting to your institution with stable angina pectoris.

 CHRONIC CAD PROGNOSTICATION ANSWERS