The effect of transplant center volume on survival after heart transplantation: a multicenter study.

OBJECTIVE

Few studies have examined the association between procedural volume and clinical outcomes in heart transplantation. This retrospective study was performed on a contemporary cohort of heart transplant recipients to better elucidate the effect of transplant center volume on 1-year mortality.

METHODS

Data from the Scientific Registry of Transplant Recipients were used to analyze the relationship between transplant center volume and short-term survival. Center volume designation (very low, low, medium, and high) was assigned on the basis of quartiles with approximately equal numbers of patients per group. Survival differences were explored using Cox proportional hazards modeling to adjust for differences in variables between volume groups and to determine variables associated with 1-year mortality.

RESULTS

Between January 1, 1999, and May 31, 2005, 13,230 heart transplantations were performed at 147 transplant centers in the United States. Although most recipient and donor characteristics were similar across quartiles, larger volume centers were more likely to perform transplantations in older candidates and accept organs from older donors with longer cold ischemia times. A statistically significant relationship between transplant center volume and 1-year mortality was observed. Compared with the reference group (very low volume), the hazard ratios for the low, medium, and high-volume quartiles were 0.71, 0.64, and 0.56, respectively (P < .001 for each group compared with the reference).

CONCLUSION

There was a significant association between transplant center volume and 1-year survival. Patients who undergo cardiac transplantation at very low-volume centers are at higher risk for early mortality than those who undergo transplantation in higher-volume centers.