Cardiac complications in non-insulin-dependent diabetes mellitus

Abstract

There is clear evidence of the negative influence of type I or II diabetes non-insulin-dependent diabetes mellitus (NIDDM) on the prevalence, severity, and prognosis of cardiovascular disease. Epidemiologic studies have confirmed the relationship between NIDDM and the occurrence of coronary artery disease (CAD) and cardiac heart failure (CHF). The clinical aspects of NIDDM cardiac complications include a high rate of silent events, which merit an improvement in their diagnosis and treatment. Besides pharmacological therapy, aggressive approaches including percutaneous transluminal coronary angioplasty (PTCA), and coronary surgery should be considered for the treatment of stable angina. In some subgroups, the benefit of surgery has been proven. Available data indicate that diabetes (both type I and II) is a risk factor for an increase in morbidity and mortality following coronary bypass surgery. These data do not differentiate results between type I and type II diabetes. The indications for surgical revascularization are: three-vessel disease, left main artery stenosis, two-vessel disease including proximal left anterior descending artery stenosis, and two-vessel disease with left ventricular dysfunction. For PTCA, diabetes (type I more than type II) renders the technique more difficult and restenosis more frequent. From the results obtained in the general population and from a few specific studies, it is suspected that, in type II diabetes, PTCA and CABG are superior to conventional medical treatment. However, further specific studies on the beneficial effects of PTCA/CABG over optimal medical therapy are needed, at least in some angiographic conditions. Management of the diabetic patient with acute myocardial infarction is for the most part similar to the nondiabetic patient, with certain special considerations. Treatment includes thrombolytic therapy, invasive management, surgery, FTCA, β blocker use, and aspirin use. Finally, diabetes mellitus is a cause of systolic and diastolic function, leading to clinical signs of CHF. Conventional medical therapy also applies to cardiac failure complicating diabetes. Medical therapy includes as the first line diuretics and angiotensin-converting enzyme inhibitors. We conclude that cardiac care can be improved in diabetic patients. For the time being, the first step is to improve the detection of coronary artery disease. As serious events are more likely to occur in the diabetic population, it would be easier (shorter studies and less patients) to demonstrate the benefit of a selected therapy. Further studies are therefore required. In the meantime, special efforts can be made: (1) prevent the development of coronary artery disease. Preventive measures aimed at the control of risk factors at the individual level must be optimal. What should be promoted is a more global approach to the patient, taking into account all parts of the risk factor profile, in order to amplify the reduction in risk and in cardiovascular morbidity and mortality. (2) When CAD is confirmed: the goal is to prevent all major cardiac events: unstable angina, myocardial infarction, sudden death, and CHF secondary to silent ischemic events. This can be achieved through the improvement of the accuracy of noninvasive diagnostic procedures, taking into account the cost of these procedures and the absence of pain perception in diabetic patients.