Heart transplantation can extend and improve the quality of life for the lucky recipient, but not without risk. Aside from organ rejection, the heart recipient is at risk for cardiac allograft vasculopathy (CAV) (Ramzy et al., 2005)–hardening/thickening of the vessels in the heart. Unlike atherosclerosis, which is caused by the buildup of plaque that inhibits the blood flow in a specific spot, in CAV, the inner most tissue thickens over a larger part of the blood vessel and reduces blood flow. Consequently, CAV raises the risk of premature death for the heart recipient.
Can CAV be detected early enough to reduce risk? Not always. Some methods for detecting CAV are invasive, only detect 10 to 50% of cases and cannot look at the entire heart due to areas being too small for evaluation (Ramzy et al., 2005). Non-invasive means certainly have an appeal and one approach, dobutamine stress echocardiography (developed decades ago), finds CAV about 80% of the time (Ramzy et al., 2005). Even after all this time, diagnosis still proves challenging (Lee et al., 2018).
Perhaps proteins in a blood sample can supply a solution? A team of researchers from Canada sought to see if proteins circulating in the blood could offer insight into the biology and potentially offer up treatment solutions for CAV (Almufleh et al., 2019).
In a small study, the team used our SomaScan® technology to analyze samples from patients who received a heart transplant and later developed CAV. In the team’s findings, fourteen proteins stuck out like a Las Vegas neon light in patients with CAV versus heart transplant recipients free of CAV. Even more profound, the team saw four proteins that have the potential to signal that the patient has severe CAV! This suggests that it may indeed be possible to have a non-invasive method capable of diagnosing CAV and specifying the severity.
The proteins identified have roles in cell death and injury, inflammation, platelet activation or coagulation. It is tantalizing to think that treatments currently available to treat disorders that involve these pathways could help those with CAV.
Before we all get too caught up in this moment of hope, the Canadian team also noted the limitations of their small study of thirty-six patients. Yet, it does lay the groundwork for recipients potentially keeping the heart longer and reducing their risk of death. This study joins hundreds of others in demonstrating that large scale measurement of proteins in blood can supply solutions!
Almufleh, A., Zhang, L., Mielniczuk, L. M., Stadnick, E., Davies, R. A., Du, Q., . . . Chih, S. (2019). Biomarker discovery in cardiac allograft vasculopathy using targeted aptamer proteomics. Clin Transplant, e13765. doi:10.1111/ctr.13765
Lee, M. S., Tadwalkar, R. V., Fearon, W. F., Kirtane, A. J., Patel, A. J., Patel, C. B., . . . Rao, S. V. (2018). Cardiac allograft vasculopathy: A review. Catheter Cardiovasc Interv, 92(7), E527-E536. doi:10.1002/ccd.27893
Ramzy, D., Rao, V., Brahm, J., Miriuka, S., Delgado, D., & Ross, H. J. (2005). Cardiac allograft vasculopathy: a review. Can J Surg, 48(4), 319-327.