Definition
Cardiac allograft vasculopathy is an accelerated type of coronary artery disease in people who have had a heart transplantation. Signs and symptoms
Unlike the chest tightness of angina in those who have not had a heart transplant, people with CAV typically do not experience chest pain because the donor heart has lost its nerve supply. A few regain nerves some years later and may develop unusual 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. Risk factors
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. Mechanism
Immunological (innate and adaptive) and nonimmunological factors contribute to the complex pathogenesis of CAV.In those nontransplanted people who develop coronary artery disease due to atherosclerosis, progression of disease is slow, histological changes are confined mainly to the main coronary arteries and arterial dilatation is observed as a form of compensatory remodelling.
Intravascular ultrasound (IVUS)
Intravascular ultrasound (IVUS) is more sensitive at reliably detecting subtle changes in the thickness of the intimal layer of the artery walls and provide measurements of artery lumen. Following transplantation, serial measurements are compared to the baseline. A greater than 0.5 mm increase in intimal thickness one year after transplantation is predictive of CAV changes on angiography within five years. The paradoxical reduction in the number of blood vessels, can also be detected by intravascular ultrasound.IVUS, however, tends to be used for research due to its drawbacks of being invasive, requiring the use of contrast material and cost. Dobutamine stress-echocardiography (DSE)
Alternatively, dobutamine stress echocardiography (DSE) is commonly performed and has an 85% sensitivity for the presence of CAV. A negative DSE correlates with a good prognosis.Other noninvasive diagnostics include positron emission tomography and computed tomographic angiography (CT angiography). In addition, ECGs may show atypical features of ischaemia. Biomarkers
Biomarkers for increased risk of CAV include C-reactive protein, serum brain natriuretic peptide and troponin I have been suggested. Classification
The degree of CAV after heart transplantation has been obtained from a variety of sources including The Cardiac Transplant Research Database, the ISHLT registry and The United Network for Organ Sharing registry.The International Society for Heart and Lung Transplantation (ISHLT) have formulated and standardized a terminology, based on diagnostic findings, to define the presence and severity of CAV, which in turn reflects prognosis. The severity of CAV is defined by the degree of narrowing of the coronary arteries and the presence of restrictive heart disease.