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Member Research and Reports

Member Research and Reports

UAB Researchers Assess Predictors of Thromboembolic Events

Ventricular assist device patients (VAD) are at enhanced risk for a condition called thromboembolism, which is defined as a blockage of a blood vessel caused by a dislodged clot. Biomarkers of the rupture of red blood cells — which include lactate dehydrogenase (LDH) and poorly controlled international normalized ratio (INR) — have been identified as predictors of the condition. In a recent study assessing 115 participants, placed between 2006 and 2012, who were ages 19 years and older and had continuous flow VAD, Dr. Amelia Boehme, former doctoral candidate in the department of epidemiology at the University of Alabama at Birmingham and current Neuroepidemiology Fellow at Columbia University Medical Center, evaluated the link between LDH elevation at various time points and thromboembolism. Dr. Nita A. Limdi, professor in UAB’s department of neurology, served as the primary mentor for this research and the subsequent manuscript that stemmed from doctoral research. This work was funded by a pre-doctoral fellowship from the American Heart Association with Dr. Limdi as the mentor. Additional UAB co-investigators are Dr. Russell L. Griffin, assistant professor; Dr. Emily B. Levitan, associate professor; Dr. Russell L. Griffin, assistant professor; and Dr. Gerald McGwin, professor and vice chair, in the department of epidemiology; as well as Dr. T. Mark  Beasley, associate professor in the department of biostatistics, section on statistical genetics; Dr. Salpy V. Pamboukian, associate professor in the division of cardiovascular disease; and Dr. James F. George, professor in the division of surgery.

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[Photo: Dr. Amelia Boehme]

“Over the 51.3 person-years of follow-up, a total of 23 first thromboembolic events occurred. Patients with elevated LDH on the day of VAD implantation had an increased risk for thromboembolism (hazard ratio [HR]: 4.72; 95 percent confidence interval [CI]: 1.44-15.4; p = 0.01). There was an increased risk of thromboembolism with early LDH elevation within the first month post-VAD (HR: 4.95; 95 percent CI: 1.69-14.4; p = 0.003) and estimated glomerular filtration rate below 30 before VAD implantation (HR: 4.74; 95 percent CI: 1.12-20.1; p = 0.0346), whereas there was a decreased risk with good anticoagulation control (HR: 0.30; 95 percent CI: 0.10-0.86; p = 0.0247),” says Dr. Boehme.

The study, which is the first to emphasize the connection between elevated LDH on implantation day and post-VAD thromboembolism, stresses the raised risk of experiencing thromboembolism in conjunction with initial LDH elevation and the advantages of maintaining time in the beneficial INR range.

“Predictors of Thromboembolic Events in Patients with Ventricular Assist Device” was published in the November-December issue of the ASAIO Journal.

Journal article: http://www.ncbi.nlm.nih.gov/pubmed/26418204