Cardiac allograft vasculopathy (CAV) is a progressive type of coronary artery disease in people who have had a heart transplant. As the donor heart has lost its nerve supply there is typically no chest pain, and CAV is usually detected on routine testing. It may present with symptoms such as tiredness and breathlessness.It arises when the blood vessels supplying the transplanted heart change in structure. They gradually narrow and restrict its blood flow, subsequently leading to impairment of the heart muscle or sudden death. In addition to the same risk factors for coronary artery disease due to the build up of plaque, CAV is more likely to occur if the donor was older or died from explosive brain death, and if there is cytomegalovirus infection. Its mechanism involves immunological (innate and adaptive) and nonimmunological factors, with distinct features on histological samples of coronary arteries. Other major causes of death following heart transplantation include graft failure, organ rejection and infection.Diagnosis is by regular follow-up and monitoring of the transplanted heart for early signs of disease. Tests include coronary angiography, intravascular ultrasound, dobutamine stress echocardiography, positron emission tomography, computed tomographic angiography (CT angiography) and several biomarkers.Statins and aspirin are commenced early after transplantation and on detection of CAV. Medications including sirolimus and everolimus can slow disease progression. A repeat heart transplantation may be required.CAV affects around half of heart transplant recipients within 10 years. It contributes to the death of 11-13% one year from heart transplantation.
History
Unlike rejection and infection, CAV in the transplanted heart was not initially a predicted outcome. Early survivors of heart transplants soon developed this form of vasculopathy of their coronary arteries, initially identified at post-mortems. There were early suggestions that preventing cytomegalovirus (CMV) infection could decrease the prevalence of CAV. The impact of CAV has changed over time, with early recipients being younger, having more rejection and cardiovascular risk factors and less use of statins. Later recipients used statins routinely and were introduced to the immunosuppressive agent mycophenolate mofetil (MMF) and CMV prophylaxis. In addition, the later recipients were monitored for antibody-mediated cardiac allograft rejection (AMR).Before 2010 there was no uniform international standards for the nomenclature of CAV. A consensus statement on a standard language for CAV was first published in 2010 by the ISHLT. This was devised in a similar way to the earlier acute rejection grading system by endomyocardial biopsy. Research directions
Antibody-mediated cardiac allograft rejection (AMR) is a significant factor leading to the rapid progression of CAV. Future research directions in this area may include prospective databases that correlate clinical factors with surveillance of the incidence and severity of AMR, the frequency of CMV infection, and the use of immunosuppressants. The role of inducing immune tolerance has yet to be established. == References ==