Undergoing orthotopic heart transplantation at high-volume centers (those that perform more than 15 procedures per year) leads to better outcomes, according to a study published in the January issue of the Journal of Thoracic and Cardiovascular Surgery. It was found that high-risk patients who undergo transplants at low-volume centers had “exceedingly high” mortality rates; however, researchers found that center volume mattered less for lower risk patients.
George J. Arnaoutakis, MD, of Johns Hopkins Hospital in Baltimore, and colleagues developed a 50-point recipient risk index to predict short-term mortality post-orthotopic heart transplant as a means to evaluate the relationship between institutional volume and recipient risk post-orthotopic heart transplant.
To do so, Arnaoutakis et al used the United Network for Organ Sharing database to identify 18,226 patients who underwent transplant at 141 medical centers between January 2000 and April 2010. Transplant centers were stratified by mean annual volume during the study and the researchers calculated Preoperative Index for Mortality Prediction After Cardiac Transplantation risk scores.
The study’s primary endpoints were 30-day and one-year survival rates.
Of the 18,226 patients who underwent transplant, 1,173 patients received care at low-volume centers (less than seven procedures per year), 5,353 received care at medium-volume centers (seven to 15 procedures performed per year) and 11,700 patients received care at high-volume centers (more than 15 procedures/year).
Arnaoutakis et al reported one-year mortality rates to be worse for those who received transplants at low-volume centers. Additionally, the researchers found a link between center volume and patient risk score for one-year survival rates, concluding that “effect of risk on mortality at low-volume centers greater than from either variable analyzed individually."
When transplantation was performed at higher-volume centers, one-year survival was improved compared with medium and low-volume centers. These numbers were 79 percent vs. 75 percent vs. 64 percent, respectively.
“High-risk patients had higher mortality at low-volume centers; differences dissipated among lower-risk recipients,” the authors summed. “These data support a mandate for high-risk transplants at higher-volume centers.
“High risk patients have an exceedingly high mortality rate when transplanted at low volume centers, which dissipates at higher volume centers.”