Effect of institutional volume and academic status on outcomes of coronary interventions: the IMPACT-II experience.
BACKGROUND
Rates of morbidity and mortality after interventional procedures are reported to be inversely associated with institutional volume.


METHODS
This study assessed both procedural volume and academic status at the 82 US centers that participated in the IMPACT-II trial. Interventional volumes at the sites ranged from 90 to 3300 cases per year. Patients were randomly assigned to a platelet glycoprotein IIb/IIIa inhibitor (eptifibatide) or placebo during procedures done by experienced operators. The primary end point was the composite of death, myocardial infarction, nonelective repeat coronary intervention, or nonelective coronary artery bypass surgery at 30 days, or placement of an intracoronary stent for abrupt closure during the initial procedure.


RESULTS
Baseline patient characteristics and median length of stay were similar between the academic and nonacademic centers. In univariable analysis, volume as a continuous variable had a nonlinear relation with the incidence of the composite end point, with better outcomes noted at the highest volume institutions. Academic status did not predict outcome. When added to a predictive model that contained the variables unstable angina, weight, prior coronary artery bypass grafting, heart rate, and platelet count, procedural volume continued to be associated with the composite outcome (P =.04).


CONCLUSIONS
We conclude that among hospitals participating in this trial, there is a nonlinear relation between annual interventional volume and outcomes. This relation is complex, involving variations in periprocedural infarction rates and additional, undefined institutional differences (other than academic status) that result in differences in procedural outcome.
Gilchrist
I C
IC
Pennsylvania State University, Duke Clinical Research Institute, Hershey, PA, USA.
Gardner
L H
LH
Muhlestein
J B
JB
Arnold
A M
AM
Lincoff
A M
AM
Califf
R M
RM
Tcheng
J E
JE
Topol
E J
EJ
D000046:Academic Medical Centers / Q000592:standards / Q000706:statistics & numerical data*; D000368:Aged; D000789:Angina, Unstable / Q000188:drug therapy* / Q000401:mortality; D000077542:Eptifibatide; D005260:Female; D005500:Follow-Up Studies; D006785:Hospitals, University / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009096:Multi-Institutional Systems / Q000592:standards / Q000706:statistics & numerical data*; D017063:Outcome Assessment, Health Care; D010455:Peptides / Q000627:therapeutic use*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors*; D012189:Retrospective Studies; D015996:Survival Rate; D014481:United States / Q000453:epidemiology
D010455:Peptides; D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D000077542:Eptifibatide