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Case History
| A 70 year old female presented with a lower central chest choking radiating to the throat and top of head giving her a headache with pins and needles in hands. She relates the episodes to anger and nervous tension caused by her husband’s behavior. She claims that walking, if anything, gives her relief from this discomfort. The discomfort is of uncertain duration. It is classified by the cardiology consultant as non-anginal chest pain. Her father had an MI around age 70. Her lipid profile revealed: cholesterol 5.81, triglycerides 0.86, HDL 1.52, LDL 3.89. She has no known hypertension, diabetes or smoking history. Physical exam was only remarkable for a BP of 150/90 mm Hg. An exercise electrocardiogram was performed. The patient achieved 11 METS, heart rate 152, BP 180/90 mm Hg, RPP 27,360 without angina. The electrocardiographic response was positive beginning at 9 METS, heart rate 133, reaching 2 - 2.5 mm horizontal in leads V5-V6. |
Questions
1. What is the pre-test and the post-test probability of significant obstructive coronary artery disease? Describe how you calculated this probability utilizing Bayes’ theorem. If the patient’s chest discomfort were more characteristic and classified as atypical angina and if there were hypertension and hypercholesterolemia, how would this affect the post-test probability calculation?
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2. Describe the scintigraphic findings and re-calculate the post-test probability of obstructive coronary artery disease. Once again, detail how you go about recalculating the obstructive CAD probability with the new scintigraphic evidence. Has an end-point for diagnostic testing been achieved in this patient? Is a diagnostic coronary angiogram indicated?
3. Discuss the diagnostic accuracy of exercise nuclear stress testing: (a) overall sensitivity specificity (b) women vs. men (c) thallium vs. sestamibi (d) exercise vs. pharmacological stress (e) how gated SPECT may improve test accuracy (f) nuclear vs. stress echocardiography.
4. Present a rational cost-effective algorithm for diagnostic non-invasive stress testing in your hospital with both stress electrocardiography and stress nuclear testing availability. Make sure to include patients with resting ECG abnormalities, LVH, patients on Digoxin and patients with exercise limitations in your algorithm.
