Cardiac Manifestations In HIV Disease Injection Drug Users Are More Susceptible
Recent estimates suggest that, within the United States, as many as 5000 patients per year may have cardiac complications resulting from HIV infection. Cardiac involvement is being identified more often in patients with HIV/AIDS.
Heart problems in HIV-positive individuals have been observed in small studies of groups of patients at sites around the world. It is difficult to estimate the true prevalence of cardiac abnormalities in HIV-infected populations, since cardiologists treat heart-related problems in those patients that are referred to them from general practitioners. Therefore, the patients seen by them are a selected group of individuals. No large scale studies have been performed to determine this important data in the general HIV-infected population.
Individuals with HIV/AIDS may have pericardial, myocardial and/or endocardial disease. Pericardial represents the sac around the heart, endocardial represents the area within the heart, and myocardial represents the musculature of the heart.
The cardiac manifestations observed in HIV/AIDS include cardiomyopathy (problems with the heart muscle), pericardial effusion (problems with the fluid surrounding the heart), mitral valve prolapse (heart valve problem), bacterial endocarditis (infection of the heart itself), and alterations of contractility (beating) of the heart.
It's difficult to determine the incidence of heart problems in individuals with AIDS at various stages of the disease ranging from asymptomatic to AIDS. About 50% of PWA's demonstrate heart problems, appearing only in the end stages, the majority being injection drug users (IDU's).
Most individuals with HIV/AIDS usually have no overt evidence of cardiac disease. HIV+ individuals, upon referral, may present with a wide range of cardiac symptoms in association with abnormal findings from an electrocardiogram (EKG) and/or echocardiogram (ECHO), (tests to check heart function). These symptoms and abnormalities requiring referral may include shortness of breath, an abnormal EKG, cardiomegaly (enlargement of the heart), and/or assessment of possible infective endocarditis. In one large group of patients with HIV infection, echocardiogram disclosed cardiac abnormalities in 17% of the cases. Sometimes when heart abnormalities do develop, the signs and symptoms may be misinterpreted to be the result of noncardiac causes (pulmonary failure or infections) that can mimic heart failure.
What appears to be the most common cardiac problem in adults is bacterial endocarditis, which generally has been observed in drug users. It is unclear, however, as to whether HIV or AIDS alters the susceptibility to infective endocarditis and/or influences mortality. Some studies have shown that drug-injection practices may be a confounder for the association between HIV infections and bacterial endocarditis.
Infective endocarditis can vary in its presentation from obvious, full-blown sepsis, to obscure, flu-like syndromes. Patients with infective endocarditis usually develop symptoms within 2 weeks of becoming infected. Complaints can be as nonspecific as malaise, fever, night sweats, and anorexia, or as drastic as manifestations of acute congestive heart failure.
To determine the cause of endocarditis, physicians may ask patients whether they have received any dental treatment in the last 6 months, indicating possible exposure to bacterial infection. This is especially true for the practitioner who is unsuspecting of a patient¹s drug use. Bacterial endocarditis is frequently associated with musculoskeletal complaints. Low back pain may be a presenting symptom.
A study of inner-city crack cocaine users found a significant gender difference in reported endocarditis among light users of crack, with more women than men self-reporting a history of endocarditis.
Right-sided endocarditis involves the tricuspid &/or pulmonic valve and is more common with injection drug users; left-sided involves the mitral &/or aortic valve.
Diagnosis is based on symptoms and signs. Confirmation requires identification of the responsible organism from blood culture. Imaging studies (pictures) of the heart provide useful information. Standard echocardiography is the most useful imaging method. Magnetic resonance imaging and computerized tomography may also be useful in the diagnosis.
Endocarditis associated with injection drug use is usually secondary to staphylococci, gram- negative bacilli, or streptococci. Fungal endocarditis is usually associated with a prolonged course of IV antibiotics, but may also occur after cardiac surgery or injection drug use. In patients with HIV/AIDS, Pneumocystis carnii or fungi may also cause endocarditis.
The patient with infective endocarditis may start IV antibiotics after obtaining appropriate cultures. Known or suspected drug users may have resistant staphylococcal infections requiring treatments with vancomycin and an aminoglycoside. If the endocarditis is not related to drug use, the individual may receive an anti-staphylococcal penicillin along with an aminoglycoside. Surgical therapy is rarely used in the HIV+ person.
In a study of 57 cases of endocarditis in 51 drug users in Italy, 86% of the participants had CD4 cell counts less than 200. Fever was the most frequent symptom with X-ray abnormalities secondary. The tricuspid valve was the affected area for 59% of patients. Staphylococcus aereus was the most frequently isolated germ (48%), being resistant in 15% of cases, thereby causing a slower response to treatment.
Prevention of endocarditis in drug users is through the use of clean needles and cleanliness of the injections site. In a study of drug users, the risk of endocarditis among those who never cleaned injection sites was found to be 3.9 times higher. When injection sites are frequently used, the risk of infection is increased due to greater exposure to bacteria. Skin-cleaning guidelines should be incorporated into injection hygiene messages. A substantial number of IDU¹s in the study reported occasional skin cleaning at injection sites, suggesting that this is a behavior which can be promoted with some success.
Since it is not yet known at what stages an individual with HIV/AIDS is at highest risk of infective endocarditis, the diagnosis becomes very difficult. It is clear from the lack of information in well-controlled large follow-up studies, that cardiac complications in HIV, and especially endocarditis in the IDU represents a significant diagnostic and therapeutic challenge for the HIV practitioner and cardiologists. Future research is warranted in this area to determine the actual prevalence of cardiac manifestations and their risk factors.
(Dr. Shaker Irwin is the Senior Clinical Research Scientist in the Pacific Oaks Medical Group (POMG) Department of Research and Scientific Investigations (RSI). She is responsible for the recruitment of women to clinical studies through both RSI and the Women¹s Care Center at POMG.)