Waiting times and prioritisation for coronary artery bypass surgery in New Zealand

OBJECTIVES To review the New Zealand coronary artery bypass priority score instituted in May 1996, and specifically to determine whether it prioritises patients at high risk of cardiac events while waiting. The New Zealand score is compared with the Ontario urgency rating score, and waiting times for surgery are compared with the maximum times recommended by the Ontario consensus panel. DESIGN Retrospective review of patients accepted for isolated coronary artery bypass surgery between 1 January 1993 and 31 January 1996. SETTING Green Lane Hospital, Auckland, New Zealand. MAIN OUTCOME MEASURES Waiting time, cardiac death, myocardial infarction, and cardiac readmission. RESULTS The median waiting times were five days for hospital cases (n = 721) and 146 days for out of hospital cases (n = 701). Of the latter group, 28% waited more than a year, 33% had their surgery expedited because of worsening symptoms, and 19% failed to meet the cut off point set by the New Zealand score for acceptance onto the list. Twenty two patients died, 18 on the outpatient waiting list (waiting list mortality 2.6%, risk 0.28% per month of waiting), and 132 were readmitted, 12% with myocardial infarction and 76% with unstable angina. Risk factors for a composite end point of death or myocardial infarction and/or cardiac readmission were: previous coronary artery bypass surgery (p = 0.001), class III or IV angina (p = 0.002), and hypertension (p = 0.005). The New Zealand score did not identify those at risk. Excluding hospital cases, 32% had surgery within the time recommended by the Ontario consensus panel. CONCLUSIONS Waiting times for coronary artery bypass surgery in New Zealand are considerably longer than those in Ontario, Canada. By using a numerical cut off point, implementation of the New Zealand priority scoring system has restricted access to coronary surgery on the basis of funding constraints rather than clinical appropriateness. The score does not add greatly to the clinicians’ prioritisation in predicting those patients who will suffer events while waiting.