Effect of operator and institutional volume on clinical outcomes after percutaneous coronary interventions performed in Canada and the United States: A brief report from the Enhanced Suppression of the Platelet glycoprotein IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) study

Abstract

BACKGROUND:The Enhanced Suppression of the Platelet glycoprotein IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial compared the use of eptifibatide with placebo in 2064 coronary intervention patients. It was previously reported that Canadian patients had reduced rates of 30-day and one-year death, myocardial infarction (MI) or targetvessel revascularization (TVR) compared with patients in the United States (US). OBJECTIVE: To examine whether operator or institutional volume differences explain the regional variation in clinical outcome. METHODS AND RESULTS:Each site received an operator and institutional volume survey. Fifty-seven sites (62%) returned complete data on 1338 patients. In this smaller cohort, Canadian patients had reduced rates of 30-day and one-year death, MI or TVR compared with US patients (6.3% versus 10.3% and 14.9% versus 20.1%, respectively; P<0.05 for both comparisons). Among 176 physicians with a median of 13 years experience, the median operator volume was 200 cases per year. Operators with fewer than 100 cases per year had higher rates of 30-day death, MI or TVR (13.2% versus 8.7%; P=0.18) and large MI (7.7% versus 3.3%; P=0.06) than those with 100 or more cases per year. The median institutional volume was 1064 cases per year. Canadian and US centres had similar operator and institutional volumes. By multivariate modelling, operator volume was not predictive of adverse clinical events. However, the rates of 30-day and one-year death, MI or TVR fell by 3% for every 100 patients treated by the institution (OR 0.97; P=0.058 and P=0.002, respectively). Enrollment in Canada was associated with improved outcomes at 30 days (OR 0.50; P=0.001) and one year (OR 0.66; P=0.001) despite inclusion of volume variables in the models. CONCLUSIONS: In the ESPRIT study, institutional volume was associated with a modest reduction in risk of death, MI or TVR over short-and long-term follow-up periods. The Canadian and US investigators and institutions selected in ESPRIT had similar annual procedural volumes. Therefore, volume variables did not explain the differential risk of clinical events observed for patients enrolled in the two countries. MÉTHODOLOGIE ET RÉSULTATS :Chaque établissement a reçu un sondage sur le volume de l'opérateur et de l'établissement. Cinquante-sept établissements (62 %) ont retourné des données complètes sur 1 338 patients. Dans cette cohorte plus petite, les patients canadiens présentaient un taux réduit de décès au bout de 30 jours et d'un an, d'IM ou de RVC par rapport aux patients des États-Unis (6,3 % par rapport à 10,3 % et 14,9 % par rapport à 20,1 %, respectivement; P<0,05 dans les deux comparaisons). Chez les 176 médecins ayant une expérience médiane de 13 ans, le volume médian de l'opérateur était de 200 cas par année. Les opérateurs voyant moins de 100 cas par année présentaient un taux plus élevé de décès au bout de 30 jours, d'IM ou de RVC (13,2 % par rapport à 8,7 %; P=0,18) et de gros IM (7,7 % par rapport à 3,3 %; P=0,06) que ceux en voyant au moins 100 par...

Impact of Annual Operator and Institutional Volume on Percutaneous Coronary Intervention Outcomes

“…The relationship of these outcomes and operator or institutional volume has not been shown earlier. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]35 Our study demonstrates a statistically significant inverse association between operator volume and outcome (in-hospital mortality and peri-procedural complications) in the current practice. Our results are in agreement with results from previous studies done both in the percutaneous transluminal coronary angioplasty and the stent era.…”

“…Our results are in agreement with results from previous studies done both in the percutaneous transluminal coronary angioplasty and the stent era. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]35,36 Previous studies have been limited by the number of centers, 12,20 state-based registry data, 8,14,15,18 inclusion of only limited cohorts, 16 lower sample size, 8,9,[11][12][13][14][15][16][17][18]20 foreign studies, 11,19,21 and most importantly they lack data from recent era. 6,7,9,16 Previous studies, which have shown a decrease in mortality with increasing operator volume, have failed to reach statistical significance because of low sample size, large confidence interval, or low procedure related mortality.…”

“…Few of the previous studies have reported a combined effect of institutional and operator volume on PCI outcomes. 19,37 These studies have shown contradictory results, with 1 study showing operator volume to be more predictive of outcomes 37 whereas the other did not. 19 We found both the operator and institutional volume to be individually predictive of outcome when not controlled for the other variable (Table 4 and Table III in the online-only Data Supplement).…”

“…19,37 These studies have shown contradictory results, with 1 study showing operator volume to be more predictive of outcomes 37 whereas the other did not. 19 We found both the operator and institutional volume to be individually predictive of outcome when not controlled for the other variable (Table 4 and Table III in the online-only Data Supplement).A large body of evidence supports the existence of a relationship between hospital volume of PCI and outcome, although only a few such studies relate total hospital PCI volume to outcome of acute myocardial infarction. 21,38 Spaulding et al 38 examined the relationship between hospital PCI volume and outcomes after emergency PCI procedures from the French Registry; a clear inverse relationship existed between hospital volume and mortality for emergency PCIs, which persisted after multivariable adjustment.…”

“…Some of these data were derived from state registries and are dated. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] The purpose of this study was to determine the association of annual PCI operator and institutional volume with in-hospital mortality, peri-procedural complications, length of hospital stay, and cost of hospitalization using the nation's largest available all-payer insurance inpatient database in a recent era (2005)(2006)(2007)(2008)(2009)) during which procedural techniques and practices have remained relatively stable.…”