Use of Troponin Testing after Non-cardiac Surgery

Myocardial injury after noncardiac surgery (MINS), which is most often asymptomatic, is associated with increased mortality and morbidity. In 2017, the Canadian Cardiovascular Society (CCS) published guidelines recommending broad post-operative troponin surveillance in high-risk patients having major non-cardiac surgery. The objectives of this thesis were to: (1) evaluate the proportion of patients having major non-cardiac surgery in Ontario that would meet guideline recommendations for routine post-operative troponin testing; (2) determine the patient-, surgical-, and hospital-factors associated with post-operative troponin testing; and (3) evaluate whether high-intensity troponin testing practices at the hospital-level were associated with fewer adverse outcomes after major non-cardiac surgery. In Chapter 2, I identified 257,704 patients who underwent non-cardiac surgery in Ontario. Applying the CCS guidelines to this cohort, 71.2% of elective surgery patients and 81.0% of urgent surgery patients would have met recommendations for post-operative troponin screening, while only 10.8% and 27.1% of guideline recommended patients received post-operative troponin testing, respectively. In Chapter 3, I identified 176,454 patients undergoing orthopedic, colorectal, or vascular surgery in Ontario. Hierarchical logistic regression modeling was used to assess the association of patient-, surgery-, and hospital-factors with postoperative troponin testing. I found that troponin testing varied substantially across hospitals for selected major non-cardiac surgery procedures even after accounting for differences in patient-level cardiac risk factors. In Chapter 4, I identified 18,467 patients undergoing common vascular surgical procedures (carotid endarterectomies and abdominal aortic aneurysm repairs). Cox proportional hazards modeling was used to assess the association of hospital-specific testing intensity with 30-day and 1-year major adverse cardiovascular outcomes (MACE). Compared to patients at low-testing intensity hospitals, patients at high-testing intensity hospitals experienced a lower hazard of MACE over 30-days and 1-year. Overall, I established that CCS guidelines recommend routine troponin testing for most patients having major non-cardiac surgery. Prior to the publication of the CCS perioperative guidelines, the overall testing rate was low, and there was substantial hospital-level variation in the use of routine troponin testing. Finally, in a cohort of vascular surgery patients, I found that patients who had procedures at high-testing intensity hospitals experienced fewer adverse outcomes, thus supporting recommendations to increase testing to detect MINS in the future.

Department dc:contributor.department

Dalla Lana School of Public Health

Year dc:date.issued

2023

Author dc:creator

• Azizi, Paymon Michael

Advisor dc:contributor.advisor

• Ko, Dennis T

• Guideline
• MINS
• Myocardial injury after noncardiac surgery
• noncardiac surgery
• Revised cardiac risk index
• Troponin

Handle dc:identifier.uri

http://hdl.handle.net/1807/128106

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/128106