{"id":{"repo_id":"toronto-retro","oai_identifier":"oai:utoronto.scholaris.ca:1807/128106"},"canonical_url":"https://search.dev.ndltd.org/etd/toronto-retro/oai:utoronto.scholaris.ca:1807/128106","repository":{"repo_id":"toronto-retro","name":"University of Toronto","base_url":"https://utoronto.scholaris.ca/server/oai/request"},"display":{"title":"Use of Troponin Testing after Non-cardiac Surgery","abstract":"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.","abstract_html":"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.","abstract_has_math":false,"creators":["Azizi, Paymon Michael"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Dalla Lana School of Public Health","school":null,"contributors":[],"advisors":["Ko, Dennis T"],"committee_chairs":[],"committee_members":[],"year":2023,"date_issued":"2023-06","date_published":"2023-06","updated_at":"2026-07-27T21:28:20Z","subjects":["Guideline","MINS","Myocardial injury after noncardiac surgery","noncardiac surgery","Revised cardiac risk index","Troponin"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1807/128106","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Ko, Dennis T"]},{"key":"dc:contributor.department","label":"Department","values":["Dalla Lana School of Public Health"]},{"key":"dc:creator","label":"Author","values":["Azizi, Paymon Michael"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2023-06"]},{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2023-06-27T16:15:46Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2023-06-27T16:15:46Z"]},{"key":"dc:date.issued","label":"Date","values":["2023-06"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Guideline","MINS","Myocardial injury after noncardiac surgery","noncardiac surgery","Revised cardiac risk index","Troponin"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1807/128106"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["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."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph.D."]},{"key":"dc:title","label":"Title","values":["Use of Troponin Testing after Non-cardiac Surgery"]}]}],"canonical_facts":{"dc:contributor.advisor":["Ko, Dennis T"],"dc:contributor.department":["Dalla Lana School of Public Health"],"dc:creator":["Azizi, Paymon Michael"],"dc:date":["2023-06"],"dc:date.accessioned":["2023-06-27T16:15:46Z"],"dc:date.available":["2023-06-27T16:15:46Z"],"dc:date.issued":["2023-06"],"dc:description.abstract":["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."],"dc:description.degree":["Ph.D."],"dc:identifier.uri":["http://hdl.handle.net/1807/128106"],"dc:subject":["Guideline","MINS","Myocardial injury after noncardiac surgery","noncardiac surgery","Revised cardiac risk index","Troponin"],"dc:title":["Use of Troponin Testing after Non-cardiac Surgery"],"dc:type":["Thesis"]},"updated_at":"2026-07-27T21:28:20Z"}