Introduction:
In recent years, an association has been found between human immunodeficiency virus (HIV) and cardiovascular problems in both adults and children. Several studies have suggested a link between the incidence of cardiac illness and the poor outcome of HIV patients. There is an increase in the manifestations of HIV-related heart diseases. This has raised the alarm among healthcare professionals to unravel the pathogenesis and cause an increase in the incidence of these cardiac complications in HIV-infected people. The cardiac complications may occur due to HIV infection itself, some opportunistic infections, tumors related to AIDS (acquired immune deficiency syndrome), and a few side effects of highly active antiretroviral drug therapy (HAART).
What Is the Pathogenesis of HIV-Associated Cardiac Complications?
Various probable theories can be put forward to explain the pathophysiology of HIV-associated cardiac complications.
- It is believed that HIV damages the heart muscles (myocardium) through the mechanism of inflammation. HIV can also cause damage to the heart by increasing the susceptibility to several infections, and toxic substances, thereby leading to ischemia (blockage in the blood supply). It is also believed that various inflammatory cytokines are responsible for causing myocarditis.
- Certain autoimmune mechanisms, such as cardiac-specific autoantibodies, might play a crucial role in the pathogenesis of HIV-related heart problems. It has also been found that cardiac autoantibodies may serve as biomarkers for dysfunctioning in the left ventricle of the heart.
- A few nutritional deficiencies have also been identified as potential predisposing factors for HIV-associated heart illness. Selenium deficiency has been considered as a possible cause of cardiomyopathy. Vitamin B12 levels, growth hormone, and thyroid hormone levels may also be disrupted in HIV disease. All these nutritional deficiencies have been found to be related to left ventricular dysfunction.
- Some of the medications used to treat HIV may have potential side effects on the heart. Mitochondrial toxicity is a well-known deleterious effect of HAART (highly active antiretroviral therapy). HAART therapy has been found to be related to certain heart diseases (coronary artery diseases).
What Are the HIV-Associated Cardiac Complications?
- Dilated Cardiomyopathy- It is a disease of the myocardial muscles. It is marked by the enlargement of one or both of the ventricular chambers of the heart. There may be contractile dysfunctioning also. It is one of the most commonly found heart complications in HIV-infected people. The mortality rate was higher in children and adults associated with this complication. Treatment involves the elimination of all the risk factors along with immunomodulatory drug therapy.
- Pericardial Effusion- In about one-fifth of HIV patients, pericardial effusion can be found. Pericardial effusion is characterized by fluid accumulation within the pericardial space. It can be a chronic or acute inflammation of the pericardial space. This complication in AIDS (acquired immunodeficiency syndrome) patients is mostly related to opportunistic infections and tumors. It is a capillary leak disease that is associated with increased cytokine expression in advanced cases of HIV patients. The cardiac illness resolves on its own in almost 40 percent of the patients. The mortality rate is high in HIV-infected patients suffering from pericardial effusion.
- Endocarditis- It is a fatal bacterial infection caused by Staphylococcus aureus. It causes severe inflammation of the heart valve. The most commonly affected valve is the tricuspid valve. Thickening of the tricuspid valve is seen in this condition which can lead to emboli formation, sepsis, and abscess formation leading to lung infarction. MRI (magnetic resonance imaging) can be used to identify the condition. It commonly occurs in HIV patients who illicit drug abuse intravenously.
- Coronary Artery Disease- It occurs due to the accumulation of plaque in the coronary arteries of the heart that supply oxygenated blood to the heart muscles. The rate of prevalence and mortality linked with coronary heart disease is found to be increased among AIDS (HIV-infected) patients. HIV is supposed to accelerate the process of plaque buildup (atherosclerosis). The condition can also occur due to side effects caused by HAART therapy. Angiography is considered highly useful for the diagnosis of CAD (coronary artery disease).
- Cardiac Involvement of HIV-Associated Tumors- Several neoplastic tumors are related to HIV infection, but the involvement of the heart is very uncommon. Kaposi sarcoma (cancer formed in the endothelial cells of the blood and lymphatic vessels). It is a low-grade malignant tumor. The lesions are caused in the soft tissues of the body. Another most commonly associated tumor with HIV is lymphoma. Burkitt lymphoma is also an aggressive type of lymphoma associated with B-cells and occurs commonly in HIV infection. The right side of the heart is most commonly affected by these malignant tumors. Pericardial effusion is another condition found along with the tumors.
- Pulmonary Arterial Hypertension- The rate of prevalence of pulmonary arterial hypertension is higher in HIV-infected patients as compared to the general public (population). It may occur due to HIV infection, pulmonary fibrosis, and intravenous drug abuse. There is dysfunctioning in the right side of the heart, and the prognosis is generally poor in such cases.
- Aneurysm and Aortic Dissection- Aneurysm is rarely present in HIV-infected patients. It occurs due to the bulging of the weakened portion of the aorta or common carotid arteries. When it is associated with vasculopathy in the brain, it becomes a serious complication. Aortic dissection may occur due to a tear in the walls of the aorta. It can also lead to serious implications in HIV-infected patients in cases of acute condition. Aortic dissection may cause severe, stabbing chest pain in HIV-infected people. The treatment will usually include surgery and proper medications.
Conclusion
Cardiac complications in HIV-associated patients can be fatal and lead to serious consequences. There is an increased incidence of these cardiac illnesses with HIV infection. There is an immediate need to improve the treatment process of HIV-infected patients since many of these complications occur due to the side effects of HAART therapy. Healthcare professionals should properly diagnose these complications and treat them accordingly without any delay. Also, these cardiac complications are found to overlap each other in AIDS patients. So healthcare professionals should make use of modern imaging techniques to identify these complications at the earliest and start the treatment promptly.
