Cardiomyopathy and pericardial effusion: HIV/AIDS is recognized as an important cause of dilated cardiomyopathy, with an estimated annual incidence of 15.9/1,000 before the introduction of HAART
1. This incidence is mainly related to that of myocarditis, which is still the best-studied cause of dilated cardiomyopathy in HIV/AIDS. Myocarditis has been documented at autopsy in 40-52 per cent of patients who died of AIDS before the introduction of HAART
2. Another important cause of cardiomyopathy in HIV/AIDS is drug cardiotoxicity. Zidovudine is associated with diffuse destruction of cardiac mi-tochondrial ultrastructure and inhibition of mito-chondrial DNA replication that may contribute to myocardial cell dys-function
3. Doxorubicin (adria-mycin), which is used to treat AIDS-associated Kaposi's sarcoma and non-Hodgkin's lymphoma, has a dose-related effect on dilated cardiomyopathy
4, as does foscarnet sodium when used to treat cyto-megalovirus oesophagitis
5.
The introduction of HAART regimens, by preventing opportunistic infections and reduc-ing the incidence of myocarditis, has reduced the prevalence of HIV-associated cardiomyopathy by about 30 per cent in developed countries
6. However, the median prevalence of HIV-associated cardiomyopathy is increasing in developing countries (about 32%), where the availability of HAART is scanty and greater is the pathogenetic impact of nutritional factors
7. Nutritional deficiencies, in fact, are common in HIV-infected subjects living in developing countries and may contribute to ventricular dys-function independently of HAART
7. Selenium, as a component of glutathione peroxidase, is involved in the antioxidant response in cells and tissues and is associated with congestive cardiomyopathy and skeletal-muscle disorders. Low levels of selenium have been described in African HIV-infected patients with cardiomyopathy and recognized as an independent factor associated with cardiomyopathy in multivariate analysis
7. The selenium depletion in these patients may be responsible for the cardiotoxic effects of coxsackievirus B3 and for the ability of these viruses to enhance the toxic effects of zidovudine on skeletal and myocardial muscle
8. HIV infection may also be as-sociated with altered levels of vitamin B12, carni-tine, growth hormone, and thyroid hormone, all of which have been associated with left ventricu-lar dysfunction
9. A trend similar to that observed for cardiomyopathy has also been observed for pericardial effusion, the prevalence of which is reduced by 30-35 per cent after the introduction of HAART in developed countries, whereas in the developing countries, the prevalence of pericardial effusion is increased by 35-40 per cent, mostly related to
Mycobacterium infections
10,11.
Endocarditis: The prevalence of infective endocarditis did not vary in HIV-infected patients who use intravenous drugs after the introduction of HAART even in the developed countries, being similar to that observed in HIV-uninfected intravenous drug addicts
1. Among intravenous drug addicts, the tricuspid valve is most frequently affected and the most frequent agents are
Staphylococcus aureus (>75% of cases),
Streptococcus pneumoniae, Haemophilus influenzae, Candida albicans, Aspergillus fumigatus and
Cryptococcus neoformans2. A virulent bacteria, as the HACEK group (
Haemophilus species,
Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens and
Kingella kingae), which are often part of the endogenous flora of the mouth, can cause endocarditis in HIV-infected patients
12. A prevalence of 3-5 per cent of non-bacterial thrombotic endocarditis, also known as marantic endocarditis was seen in AIDS patients, mostly with HIV-wasting syndrome, before the introduction of HAART
2. Marantic endocarditis is now more frequently observed in developing countries with a high incidence (about 10-15%) and mortality for systemic embolization
10,11.
Pulmonary hypertension: The incidence of HIV-associated pulmonary hypertension is increased in HIV-infected patients after the introduction of HAART. It has been estimated in 1/200, much higher than 1/200,000 found in the general population
13. A key pathogenetic role in this condition is played by pulmonary dendritic cells which are not sensitive to HAART and may hold HIV-1 on their surfaces for extended time periods. The infection of these cells by HIV-1 causes a chronic release of cytotoxic cytokines (
e.g., endothelin-1, interleukin-6, interleukin-1 beta and TNF-alpha) contributing to vascular plexogenic lesions and progressive tissue damage and congestive heart failure, independently of opportunistic infections, stage of HIV disease and HAART regimens
13. Endothelin-1 receptor antagonists, such as bosentan, may be useful, even in combination with HAART in the early stages of the disease
14,15. The use of phosphodiesterase-5 inhibitors (
e.g., sildenafil), although promising, is still debated because of their interaction with protease inhibitors.
AIDS-associated neoplasms: The introduction of HAART reduced significantly the prevalence of cardiac involvement in AIDS-associated neoplasms. The prevalence of cardiac Kaposi's sarcoma in AIDS patients ranged from 12 to 28 per cent in retrospective autopsy studies performed in the pre-HAART era, with a lower prevalence for non-Hodgkin lymphoma
2. The introduction of HAART led to a reduction by about 50 per cent in the overall incidence of cardiac involvement by Kaposi's sarcoma and non-Hodgkin lymphomas. The fall may be attributable to the improved immunologic state of the patients and the prevention of opportunistic infections (human herpes virus-8 and Epstein-Barr virus) known to play an aetiologic role in these neoplasms. On the contrary, an increased prevalence of cardiac involvement of AIDS--associated tumours has been observed in developing countries in relation to the scanty availability of HAART
10.
Vasculitis: A wide range of inflammatory vascular diseases including polyarteritis nodosa, Henoch-Schonlein purpura, and drug-induced hypersensitivity vasculitis may develop in HIV-infected individuals. Kawasaki-like syndrome
16,17 and Takayasu's arteritis
18 have also been described. Some HIV-infected patients have a clinical presentation resembling systemic lupus erythematosus with arthralgias, myalgias, and autoimmune phenomena with a low titre positive antinuclear antibody, coagulopathy with lupus anticoagulant, haemolytic anaemia, and thrombocytopenic purpura
19. Drug-induced hypersensitivity vasculitis is common in HIV-infected patients receiving HAART
19.The vasculitis associated with drug reactions typically involves small vessels and has a lymphocytic or leukocytoclastic histopathology. Medical practitioners need to be especially aware of abacavir hypersensitivity reactions because of the potential for fatal outcomes. Hypersensitivity reactions of this type should always be considered as a possible aetiology for a vasculitic syndrome in an HIV-infected patient
19.
Viral infection and coronary artery disease: The association between viral infection (cytomegalovirus or HIV-1 itself) and coronary artery lesions is not clear. HIV-1 sequences have been detected by
in situ hybridization in the coronary vessels of an HIV-infected patient who died from acute myocardial infarction
20. Po-tential mechanisms through which HIV-1 may damage cor-onary arteries include activation of cytokines and cell-adhesion molecules and alteration of major-histocompatibility-complex (MHC) class I molecules on the surface of smooth-muscle cells
20. It is possible also that HIV-1-associated protein gp 120 may induce smooth-muscle cell apoptosis through a mitochondrion-controlled pathway by activation of inflammatory cytokines
21.