Referral to a cardiologist
Referral to a cardiologist should be considered when the suspicion for cardiac disease is high, there is substantial diagnostic uncertainty after initial evaluation, or if symptoms persist, despite treatment of a noncardiac cause. Further evaluation and treatment often includes coronary angiography.
Coronary angiography
Most outpatients, such as the 2 presented, can be diagnosed with clinical and noninvasive measures. Coronary angiography is most commonly used to determine the presence and extent of obstructive CHD, and to guide decisions about revascularization in high-risk patients, or in patients with an abnormal stress test.
Cardiac catheterization presents a small but real risk to the patient, involves discomfort and substantial cost, and can challenge effective resource utilization. Risks and benefits to individual patients should be discussed between primary care physician and cardiologist.
Summary
Findings in our 2 patients are summarized below. Diagnostic decisions reflect the algorithm in Figure 1and are based on current guidelines.2
Patient 1. After initial assessment, our 64-year-old asymptomatic woman still falls into “intermediate probability of CHD” due to her multiple CHD risks. Stress testing was therefore indicated. Due to her inability to exercise because of an orthopedic limitation, she underwent pharmacologic stress testing with an adenosine sestamibi study. A small inferior reversible defect was identified, suggestive of myocardial ischemia.
Aggressive medical therapy aimed at minimizing symptoms and reducing risk was selected: aspirin, a beta-blocker for ischemia and hypertension, and a statin for hyperlipidemia. Longacting nitrates or calcium-channel blockers would have been reasonable alternatives. Consideration of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker is also indicated in light of her new CHD diagnosis and glucose intolerance. She was advised to initiate a low-fat, low-carbohydrate diet and to exercise (swim) regularly to lower risk. She will be seen in 6 weeks to reevaluate her symptoms, blood pressure, and lipid and glycemic control.
Patient 2. Our male patient also warranted stress testing. He was referred for a standard stress ECG due to his normal resting ECG, and the expectation that he would be able to exercise adequately. He satisfactorily completed 10.5 minutes (10 METS) of a Bruce protocol on a treadmill exercise stress test, which was entirely normal.
This admittedly anxious individual was reassured that his chest symptoms are not due to heart disease. An empiric trial with a proton pump inhibitor could be initiated if gastro-esophageal reflux is suspected.
Conclusions
Standard treadmill exercise testing for diagnosis and risk stratification is suitable for patients with a normal resting ECG and without contraindications to exercise, as in our male patient. Those with an uninterpretable ECG should undergo either nuclear or echocardiographic imaging in concert with their exercise test. Patients in whom exercise is either contraindicated or who have a condition that interferes with exercising to the target level are candidates for nuclear or echocardiographic pharmacologic stress testing, as was indicated for our female patient. Patients with suspected CHD and for whom exercise or pharmacologic testing is contraindicated should be referred to a cardiologist for evaluation.
Finally, when selecting a specific stress imaging technique, physicians should consider the local expertise with the various techniques available, together with their strengths and limitations in the individual patient.19