Human immunodeficiency virus (HIV) is a virus that targets and weakens the body’s immune system, attacking CD4+ T cells. Without treatment, this progressive failure of the immune system can lead to acquired immunodeficiency syndrome (AIDS), making individuals susceptible to various life-threatening infections and cancers. Blood clots are masses formed by blood cells and proteins that normally stop bleeding after injury. However, when clots form inappropriately within blood vessels or fail to dissolve, they obstruct blood flow, leading to serious medical conditions.
The Link Between HIV and Blood Clot Risk
People with HIV have an increased risk of developing blood clots compared to the general population. This risk is two to tenfold higher for venous thrombosis. This increased susceptibility to clot formation persists even with effective antiretroviral therapy (ART), which manages viral load, as ART does not completely eliminate the elevated risk of thrombotic events. People with HIV may also experience blood clots at a younger age than individuals without HIV.
Biological Factors Contributing to Clot Formation
The increased risk of blood clot formation in people with HIV stems from complex biological mechanisms. Chronic inflammation and persistent immune activation are major contributors, even when the virus is suppressed by ART. HIV infection can lead to endothelial dysfunction, damaging the inner lining of blood vessels. This damage promotes clot formation.
HIV also changes the balance of coagulation proteins in the blood. Approximately 60% of people with HIV have lower levels of protein S, a natural anticoagulant. HIV proteins can also activate monocytes, leading to the release of procoagulant factors like tissue factor. While HIV-specific factors are significant, traditional cardiovascular risk factors like smoking, obesity, high cholesterol, and high blood pressure also amplify the likelihood of blood clot development.
Types of Blood Clots and Their Symptoms
Blood clots can manifest in various forms, with distinct symptoms depending on location. Deep vein thrombosis (DVT) often occurs in the deep veins, typically in the legs, causing throbbing pain, swelling, warmth, and skin color changes like redness or darkening. Sometimes, a DVT may have no noticeable symptoms.
A complication arises when a part of a DVT breaks off and travels to the lungs, resulting in a pulmonary embolism (PE). PE symptoms often include sudden shortness of breath, chest pain that worsens with breathing, rapid heart rate, a cough (sometimes with bloody mucus), anxiety, or lightheadedness. Arterial clots block blood flow in arteries, leading to conditions like heart attack or stroke. Heart attacks typically present with chest discomfort that may spread to the arms, back, neck, jaw, or stomach, accompanied by shortness of breath, sweating, nausea, or lightheadedness. Stroke symptoms often appear suddenly and include facial drooping, arm weakness, or difficulty with speech, often remembered by the acronym F.A.S.T. Other signs may involve sudden numbness, confusion, vision problems, or a severe headache.
Strategies for Prevention and Management
Preventing blood clots in people with HIV involves a multi-pronged approach focusing on both HIV-specific and general health measures. Consistent adherence to ART is important for viral load suppression, reducing overall health complications. Managing traditional cardiovascular risk factors, including a healthy lifestyle, blood pressure control, and cholesterol management, is also important. Avoiding prolonged immobility, such as during long flights or bed rest, also helps reduce clot formation risk.
Blood clot management involves medications to prevent further growth or to dissolve them. Anticoagulants, or “blood thinners,” slow the body’s ability to form new clots and prevent existing ones from enlarging. These medications may be taken for weeks, months, or years. In severe cases, thrombolytics, or “clot-busting” drugs, rapidly dissolve dangerous clots, particularly in emergencies like severe pulmonary embolism, heart attack, or stroke. Close collaboration with healthcare providers is important for personalized care, including regular monitoring and treatment adjustments.