This patient should continue his current therapy; no additional testing is indicated at this time. The leading cause of death in patients with diabetes mellitus is cardiovascular disease, but routine testing for coronary artery disease (CAD) in asymptomatic patients with diabetes does not reduce mortality. Aggressive treatment of cardiovascular risk factors, however, does improve outcomes and reduce mortality as seen in the Steno-2 study. In this study, intensive intervention with behavior modification and multiple pharmacologic interventions aimed at achieving hemoglobin A1c levels below 6.5%, blood pressure below 130/80 mm Hg, and serum total cholesterol levels below 175 mg/dL (4.53 mmol/L) resulted in a 53% reduction of cardiovascular disease in a nearly 8-year follow-up. Continued risk factor management in this patient is, therefore, the most appropriate choice.
This patient does not need an echocardiogram. He is asymptomatic, and the murmur described is consistent with mild aortic stenosis as supported by his echocardiogram 1 year ago. He should undergo an annual clinical evaluation and echocardiography every 3 to 5 years. Echocardiography at this time in the absence of a clinical change is unnecessary.
If a screening test were to be performed prior to exercise, an exercise stress test would be the most appropriate test; exercise perfusion imaging provides no additional information. In routine screening of patients with diabetes in the DIAD study, despite 22% of patients having evidence of perfusion defects on single-photon emission CT, most of which were small, mortality rates were not changed compared with patients who did not undergo screening. The event rates were low in both groups, at about 3% over nearly 5 years.
The 2012 U.S. Preventive Services Task Force statement on screening for CAD with electrocardiography (ECG) recommended against screening with resting or exercise ECG for the prediction of CAD events in asymptomatic adults at low risk for CAD events, and stated that the evidence is insufficient to assess the balance of benefits and harms of screening in asymptomatic adults at intermediate or high risk for CAD events. The 2002 American College of Cardiology/American Heart Association (ACC/AHA) guidelines also concluded that there is no evidence to support routine testing in asymptomatic adults but concluded that it is reasonable to screen for CAD in asymptomatic patients with diabetes who plan to begin a vigorous exercise program.