Researchers at UCLA have developed a blood test using gene activity data from immune cells that helps predict the survival of advanced heart failure patients receiving mechanical circulatory support (MCS) devices.
The test was 93 percent accurate in predicting one-year survival of 29 patients, lead investigator Mario C. Deng, MD, and colleagues reported in PLOS One.
Heart failure affects about six million people in the U.S., according to the authors. MCS devices were originally designed to serve as a bridge to heart transplantation, but have increasingly been used as lifelong destination therapies. However, it is difficult to accurately assess the risk of adverse events post-MCS implantation—a challenge that is further complicated by patient frailty and organ dysfunction.
“None of the current established clinical scoring and prediction tools integrate immune function parameters,” Deng et al. wrote. “They have the tendency to be imprecise in estimating risk among severely ill patients, making the therapeutic recommendation with the best survival estimate for the individual patient very difficult. Our central postulate is that OD (organ dysfunction) and patient death after MCS- or (heart transplantation)-surgery results from innate and adaptive immune cell dysfunction. Therefore, our goal is to use leukocyte immune-biology information to develop a preoperative test, which would precisely predict postoperative outcomes in the individual advanced heart failure patient.”
Deng and colleagues studied 29 individuals with advanced heart failure who underwent MCS surgery at UCLA from 2012 to 2014. The researchers collected blood samples and clinical data both one day before surgery and eight days afterward.
They classified patients by whether their organ function improved between those assessments based on two risk scores: the Sequential Organ Failure Assessment score and the Model of End-stage Liver Disease Except INR score. If patients improved in both scores, they were placed in the “improving” group. If not, they were classified as “not improving.”
Seventeen patients were listed as improving, with 88 percent of them were still alive one-year post-surgery. One-year survival was 27 percent for the 11 patients who didn’t improve.
Out of 28 genes that were differentially expressed between the two groups, the researchers identified 12 that had predictive value for one-year survival.
“Our data suggest that the preoperative dynamic recovery potential, rather than the static severity of OD, is the key prognostic property to restoring equilibrium after surgery,” Deng and co-authors wrote. “This also presents the possibility of using a preoperative blood sample to identify advanced heart failure-patients who may have a high chance of early postoperative recovery and a potentially good long-term prognosis.”
The researchers said this knowledge could eventually be used to either recommend patients for surgery or decide the procedure is futile. According to Deng and colleagues, there are 7,500 to 15,000 potential candidates for MCS in the U.S. each year who might not benefit from undergoing surgery. Properly identifying those patients could decrease the economic burden of heart failure, which is projected to explode to $97 billion annually by 2030.
The findings of the study require larger numbers for confirmation, the authors acknowledged. They plan to expand the research to analyze results for 1,000 patients from 10 sites, according to UCLA.
Deng and colleagues also noted they have initiated a follow-up study using the same protocol to evaluate the genomic blood test in heart failure patients undergoing a range of interventions, including valve replacement and repair, coronary artery bypass surgery, optimal medical therapy, PCI and heart transplantation.