A study among patients receiving Highly Active Antiretroviral Therapy (HAART) at a French hospital has revealed that more than ten per cent of patients had heart disease that was causing no physical symptoms, but which places them at increased risk of stroke or heart attack. The condition, called Silent Myocardial Ischemia, was detected after patients underwent heart monitoring during an exercise session.
Silent myocardial ischemia (SMI) occurs when the supply of oxygen to the muscles of the heart is restricted, but no pain is felt. It is an early warning sign of heart disease and increased risk of heart attack or stroke due to narrowing of the arteries. Unexpected coronary events in patients on HAART have been reported previously, but this is the first study to look at the prevalence of `silent` heart disease among patients receiving HAART.
Exercise stress testing may reveal coronary artery disease in patients with no history or symptoms; silent myocardial ischemia is predictive of major coronary events in HIV-negative adults with no symptoms of heart disease.
This study was conducted in 99 patients with no prior history of cardiovascular problems who had been receiving HAART for at least twelve months. The group was matched for baseline characteristics with 99 patients who did not undergo exercise stress testing and was not found to differ significantly in any aspect apart from age (mean 42 years in the test group versus 39 years in the control group).
This study did not compare the results of the exercise test group with an age-matched HIV-negative control group, or compare the incidence of other factors such as smoking and hypertension with an HIV-negative control group.
Eleven cases of exercise-induced silent myocardial ischemia (SMI) were identified. In two cases, patients had been diagnosed with diabetes prior to commencing HAART. Seven patients had hypercholesterolemia, but only two had elevated cholesterol levels before commencing HAART.
Central fat accumulation was more common in those with SMI ( 54% vs 17%, p=.004), as were elevated levels of cholesterol (5.46 vs 6.47 mmol/L, p=0.04) and glucose (6.47 vs 5.46 mmol/L, p=0.007 but there was no difference in duration of exposure to any antiretroviral agents, body mass index, smoking, hypertension or family history of cardiovascular disease.
SMI was also independently associated with age, indicating that cardiovascular disease in patients receiving HAART will tend to increase as a natural consequence of age, regardless of any potential increase in risk due to the metabolic complications of HAART as seen in this study. Although central fat accumulation was found to be associated with SMI in this study, data on severity of central fat accumulation prior to HAART were not presented.
Duong M et al. Exercise stress testing for detection of silent myocardial ischemia in Human Immunodeficiency Virus-infected patients receiving antiretroviral therapy. Cinical Infectious Diseases 34: 523-8, 2002.