OBJECTIVE To assess the risk of important cardiac events while waiting for coronary artery bypass surgery (CABG) in relation to the New Zealand priority scoring system; to compare clinical characteristics of patients referred for CABG in New Zealand with those in Ontario, Canada; and to compare the New Zealand priority scoring system for CABG with the previously validated Ontario urgency score.

DESIGN Analysis of outcomes in a consecutive case series of patients referred for CABG.

SETTING University hospital.

PATIENTS All 324 patients from Christchurch Hospital wait listed for isolated CABG between 1 January 1994 and 31 December 1995.

MAIN OUTCOME MEASURES Death, myocardial infarction, and unstable angina while waiting for CABG; waiting time to surgery.

RESULTS Clinical characteristics at referral were very similar, but median waiting time was longer in New Zealand than in a large Canadian case series (212 days v 17 days). While waiting for elective CABG, 44% (114/257) of New Zealand patients had cardiac events: death 4% (13/257), non-fatal myocardial infarction 6% (16/257), readmission with unstable angina 34% (87/257). Priority scores did not predict cardiac events while waiting for CABG. Indeed, death or non-fatal myocardial infarction occurred in 4% (3/76) and 8% (6/76), respectively, of those with priority scores < 35. These people are no longer eligible for publicly funded surgery in New Zealand.

CONCLUSIONS Very long waiting times for CABG are associated with frequent cardiac events, at considerable cost to both patients and health care providers. Priority scores may facilitate comparison between countries but such scores did not predict clinical events while waiting.