Background: Guidelines and Class I AHA/ACCF recommendations suggest that high volume percutaneous coronary interventions (PCI) centers produce better patient outcomes than lower-volume centers. Although limited research suggests that volume matters, most of this research is not current, and was not conducted using hospitals from a fully developed regionalized system of care.
Objective: To assess the relationship between hospital PCI volumes and two key patient outcomes: door-to-balloon (D2B) and mortality.
Methods: We examined 9,674 STEMI patients who underwent primary percutaneous intervention and 18,539 non-STEMI patients. We relied on data from a developed regional system of care in Dallas County, which has been organized for the last five year and represents 33 PCI-capable hospitals. We used data extracted from the National Cardiovascular Data Registry Action Registry from the 2010-2015. Center volume was divided into three groups: low (<200 PCIs/year), intermediate (between 200-400 PCIs/year), and high (>400 PCIs /year) volumes. We analyzed the data using general linear regression model and logistics regressions. We incorporated institutional covariates as controls, including hospital size (number of beds), teaching status, geographic location (suburban, urban), and percent of managed care. Further, we controlled for patient-level differences by incorporating type of transportation (self, EMS), patient age and gender, and patient’s condition on presentation (shock, heart failure).
Results: Mortality and door-to-balloon time were examined for each group. Unadjusted mortality rate and door-to-balloon time were significantly higher in low-volume hospitals compared with high-volume hospitals (6.2% versus 4.2%, p<0.001; 187 min. versus 114 min., p<0.005, respectively). Statistically significant association was found between volume of PCIs and D2B for those who underwent ST-elevation myocardial infarction groups. Intermediate- and high-volume centers are more likely to shorten the D2B compared to low-volume centers (OR: 3.08, P<0.04; OR: 1.29, P<0.001). Mortality was no longer significant in the multivariate analysis, adjusting for other covariates. Overall, high volume operators had better outcomes than low volume operators.
Conclusions: The higher-volume PCI hospitals have significantly reduced treatment times. This analysis of contemporary PCI suggests that volume persists as a significant influence on outcomes for STEMI, even in amidst growth of sophisticated, regional systems of care.