Regional revascularization patterns after myocardial infarction in Ontario

Area of Science:

• Cardiovascular Medicine
• Health Services Research
• Public Health

Background:

• Regional variations in coronary artery bypass grafting (CABG) use are known in Canada.
• Previous studies did not fully account for percutaneous transluminal coronary angioplasty (PTCA) or geographic disease severity variations.
• Following patients post-acute myocardial infarction (AMI) allows simultaneous assessment of both procedures and geographic impacts.

Purpose of the Study:

• To determine if regional differences exist in Ontario for the use and timing of CABG and PTCA.
• To analyze these differences in patients who recently experienced an AMI.

Main Methods:

• An inception cohort of 6,565 patients diagnosed with AMI was identified from hospital discharge abstracts (first six months of fiscal 1990).
• Patients were tracked longitudinally for subsequent CABG or PTCA within the fiscal year.
• Revascularization rates and time from AMI to intervention were compared across five major Ontario referral regions using chi-squared tests and nonparametric analysis of variance.

Main Results:

• Overall, 9.7% of patients underwent revascularization, with regional rates varying from 7.2% to 13.6% (P < 0.0001).
• The time to revascularization also showed significant regional variation (P < 0.01).
• Both CABG and PTCA use differed by region (P < 0.0001); two regions with high CABG rates had average overall revascularization due to lower PTCA use.

Conclusions:

• Significant regional variations in the use and timing of coronary revascularization were identified in this post-AMI cohort.
• Longitudinal tracking of substitutable procedures in defined cohorts offers valuable insights beyond traditional small area analyses.