Cardiac allograft vasculopathy
Cardiac allograft vasculopathy (CAV) is a common long-term complication of heart transplantation affecting up to half of people within 10 years. It arises when the blood vessels supplying the transplanted heart gradually narrow and restrict its blood flow, subsequently leading to impairment of the heart muscle or sudden death. The other major causes of death following heart transplantation include graft failure, organ rejection and infection.
People with CAV may present with a wide range of symptoms including tiredness and breathlessness, but there is typically no chest pain. As well as the same risk factors for coronary artery disease due to atherosclerosis, CAV risk factors also include older donors, cytomegalovirus infection and explosive brain death in the donor.
Its pathogenesis involves immunological (innate and adaptive) and nonimmunological factors, with distinct features on histological samples of coronary arteries.
Diagnosis is by regular follow-up and monitoring of the transplanted heart for early signs of disease. This involves invasive diagnostics including coronary angiography and intravascular ultrasound, and non-invasive investigations including dobutamine stress echocardiography, positron emission tomography, computed tomographic angiography (CT angiography) and a variety of biomarkers.
Statins and aspirin are commenced early after transplantation and on detection of CAV. Medications including sirolimus and everolimus can slow disease progression, but a repeat heart transplantation may be needed.
Unlike the ischaemic chest pain in those who have not had a heart transplant, people with CAV typically do not experience chest pain because the donor heart is denervated. A few reinnervate some years later and may develop atypical chest pain. People with CAV may present with a broad spectrum of symptoms including tiredness, nausea, or abdominal discomfort or may have no symptoms at all.Shortness of breath and arrythmias may also occur.
Similar to coronary artery disease in those who have not had a heart transplant, risk factors to CAV include high blood pressure, high cholesterol, and diabetes mellitus. Other risk factors exclusive to CAV include older donors, cytomegalovirus infection and circulating antibodies after heart transplantation. The mechanism of donor brain death,particularly explosive brain death in the donor has been shown to be a significant factor. It is probably the combination of injuries to the allograft that determine the risk of developing CAV.
Current Trends in Cardiology