Variations in the use of coronary arteriography in the UK: the RITA trial coronary arteriogram register

The Randomised Intervention Treatment of Angina (RITA) trial is comparing the effects of coronary artery bypass surgery and coronary angioplasty. During patient recruitment, the trial participants maintained a register of patients investigated by coronary arteriography. We used the register data to analyse variation in the practice and therapeutic implications of coronary arteriography between the 17 participating centres. Of 33,359 patients undergoing coronary arteriography, 85.2% had significant coronary artery disease (range 81.3%-89.3% between centres). The planned management for patients with coronary disease included coronary bypass surgery (43.3%), coronary angioplasty (15.7%) and RITA randomization (3.2%). The rate of referral for myocardial revascularization varied between centres from 47.6% to 83.4%. Multiple logistic regression analysis identified several correlates of myocardial revascularization, including the indication for investigation, extent of coronary disease and left ventricular function. After adjustment for these variables, the odds of revascularization at the different participating centres varied by a factor of 4.2. This intercentre variation in the use of revascularization procedures may reflect variation in the clinician's view of the appropriateness of myocardial revascularization in different clinical circumstances.