Changes in referral patterns for coronary revascularization: the impact on coronary artery bypass grafting surgery

Pittman, Natalia (2011) Changes in referral patterns for coronary revascularization: the impact on coronary artery bypass grafting surgery. Masters thesis, Memorial University of Newfoundland.

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Abstract

Background: -- Across Canada, waiting times for cardiac procedures, such as coronary artery bypass grafting (CABO), are higher than the ideal waiting time. From 1994 to 2002, there was a rapid increase in the number of patients receiving cardiac catheterizations and CABOs across Canada. The rates in Newfoundland and Labrador (NL) were higher than the Canadian average. This resulted in an extremely long waitlist with patients waiting longer than the acceptable benchmark time to have their surgery. In 2004, the number of people in Canada on cardiac surgery waitlists decreased significantly more than would be expected from simple waitlist management. The main reason is that the number of referral rates for CABO dropped dramatically. One major reason for this drop in referral rates may have been due to the introduction of drug-eluting stents in Canada in 2003. -- Objectives: -- The objective of this study is to identify changes in referral patterns for coronary revascularization and assess the impact on CABO waiting times in NL. This retrospective study will identify the changes that occurred during this time period and determine the reason(s) for these changes. -- Method: -- All 1341 patients who underwent a diagnostic cardiac catheterization in NL from ApriI 1, 2005 to September 30, 2005 were included in this study. Records from the Cardiac Program of Eastern Health were reviewed to determine referral rates, utilization rates, and wait times for percutaneous coronary intervention (PCI) and CABO procedures from 1998/1999 to 2007. The data obtained was compared to data from 1998/1999. -- Results: -- From 1998/1999 to 2005/2006 the number of coronary catheterizations increased by 21.6%. This was attributable to increased numbers of patients with stable angina, myocardial infarction or chest pain of uncertain etiology, treated not by revascularization procedures but by medical management. The proportion of patients diagnosed with critical coronary artery disease (CAD) decreased by 5%. Patients with critical CAD were referred for medical management, PCI, CABO or other. Referral rates increased 8.3% for medical management, decreased 4.8% for PCI, decreased 5.1 % for CABO and increased 1.6% for other. -- Between 2003 and 2007 the number of CABOs decreased by 12.7% and angioplasty increased by 8%. In 2002, the year prior to introduction of drug-eluting stents (DES), 50% of those referred for revascularization were treated with PCI compared to 59% in 2007. Within one year of the introduction half of all stents comprised DES. Total stent use has increased with an increase in DES and a decrease in bare metal stents (BMS). In 2005, 63% of stent cases received DES compared to 13.3% in 2003. Increased use of PCI for unstable angina was observed in 2005 compared to 1998/1999 (73% v 61 %), but its use in those with multi-vessel disease was similar in both years. -- From 2002 to 2007, the number of CABGs performed had an overall decrease from 568 to 492, and the waiting list went from 222 to 78. The recommended maximum waiting time (RMWT) for CABGs are being reached for most patients in the semi-urgent <2 weeks), short wait <6 weeks), delayed wait <6 weeks) and marked delay <6 months) priority groups. More than 80% of the patients in these groups are getting CABGs on time. For very urgent <24 hours) and urgent <72 hours) patients, the percent reaching the target for the RMWT is less than 50% but has increased since 1998/1999. -- Conclusion: -- The number of coronary catheterizations performed each year continues to grow, however, the proportion diagnosed with critical CAD (69%) has decreased. CABG numbers decreased at the time when DES utilization increased. Management of CAD in the twenty-first century has changed rapidly. The rapid incorporation of DES in practice has helped alleviate the problem of large CABG waitlists.

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