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Determinants of variations in coronary revascularization practices

Tu JV, Ko DT, Guo H, Richards JA, Walton N, Natarajan MK, Wijeysundera HC, So D, Latter DA, Feindel CM, Kingsbury K, Cohen EA; Cardiac Care Network of Ontario’s Variations in Revascularization Practice in Ontario Working Group. CMAJ. 2012; 184(2):179-86. Epub 2011 Dec 12.


Background — The ratio of percutaneous coronary interventions to coronary artery bypass graft surgeries (PCI:CABG ratio) varies considerably across hospitals. The investigators conducted a comprehensive study to identify clinical and nonclinical factors associated with variations in the ratio across 17 cardiac centres in the province of Ontario.

Methods — In this retrospective cohort study, the investigators selected a population-based sample of 8972 patients who underwent an index cardiac catheterization between April 2006 and March 2007 at any of 17 hospitals that perform invasive cardiac procedures in the province. The investigators classified the hospitals into four groups by PCI:CABG ratio (low [< 2.0], low–medium [2.0–2.7], medium–high [2.8–3.2] and high [> 3.2]). The investigators explored the relative contribution of patient, physician and hospital factors to variations in the likelihood of patients receiving PCI or CABG surgery within 90 days after the index catheterization.

Results — The mean PCI:CABG ratio was 2.7 overall. The investigators observed a threefold variation in the ratios across the four hospital ratio groups, from a mean of 1.6 in the lowest ratio group to a mean of 4.6 in the highest ratio group. Patients with single-vessel disease usually received PCI (88.4%–99.0%) and those with left main artery disease usually underwent CABG (80.8%–94.2%), regardless of the hospital's procedure ratio. Variation in the management of patients with non-emergent multivessel disease accounted for most of the variation in the ratios across hospitals. The mode of revascularization largely reflected the recommendation of the physician performing the diagnostic catheterization and was also influenced by the revascularization "culture" at the treating hospital.

Interpretation — The physician performing the diagnostic catheterization and the treating hospital were strong independent predictors of the mode of revascularization. Opportunities exist to improve transparency and consistency around the decision-making process for coronary revascularization, most notably among patients with non-emergent multivessel disease.

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Keywords: Cardiovascular diseases Surgery

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