Association of echocardiography before major elective non-cardiac surgery with postoperative survival and length of hospital stay: population based cohort studyBMJ 2011; 342 doi: http://dx.doi.org/10.1136/bmj.d3695 (Published 30 June 2011) Cite this as: BMJ 2011;342:d3695
- Duminda N Wijeysundera, assistant professor123,
- W Scott Beattie, professor2,
- Keyvan Karkouti, associate professor24,
- Mark D Neuman, assistant professor56,
- Peter C Austin, professor34,
- Andreas Laupacis, professor1347
- 1Keenan Research Centre, Li Ka Shing Knowledge Institute of St Michael’s Hospital, 80 Bond Street, Toronto, ON, Canada M5B 1W8
- 2Department of Anesthesia, Toronto General Hospital and University of Toronto, Toronto
- 3Institute for Clinical Evaluative Sciences, Toronto
- 4Department of Health Policy Management and Evaluation, University of Toronto
- 5Department of Anesthesiology and Critical Care, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- 6Leonard Davis Institute for Health Economics, University of Pennsylvania
- 7Department of Medicine, St Michael’s Hospital and University of Toronto
- Corresponding to: D N Wijeysundera
- Accepted 26 May 2011
Objective To determine the association of resting echocardiography before elective intermediate to high risk non-cardiac surgery with survival and length of hospital stay.
Design Population based retrospective cohort study.
Setting Acute care hospitals in Ontario, Canada, between 1 April 1999 and 31 March 2008.
Participants Patients aged over 40 years who had elective intermediate to high risk non-cardiac surgery.
Intervention Resting echocardiography within 6 months before surgery.
Main outcome measures Postoperative survival (30 days and 1 year) and length of hospital stay; postoperative surgical site infection as an outcome for which no association with echocardiography would be expected.
Results Of the 264 823 patients in the entire cohort, 15.1% (n=40 084) had echocardiography. After use of propensity score methods to assemble a matched cohort (n=70 996) that reduced differences between patients who had or had not had echocardiography, echocardiography was associated with increases in 30 day mortality (relative risk 1.14, 95% confidence interval 1.02 to 1.27), 1 year mortality (1.07, 1.01 to 1.12), and length of hospital stay but no difference in surgical site infections (1.03, 0.98 to 1.06). The association with mortality was influenced (P=0.02) by whether patients had had stress testing or had risk factors for cardiac complications. No association existed between echocardiography and mortality among patients who had stress testing (relative risk 1.01, 0.92 to 1.11) or among patients at high risk who had not had stress testing (1.00, 0.87 to 1.13). However, echocardiography was associated with mortality in patients at low risk (relative risk 1.44, 1.14 to 1.82) and intermediate risk (1.10, 1.02 to 1.18) who had not had stress testing.
Conclusions Preoperative echocardiography was not associated with improved survival or shorter hospital stay after major non-cardiac surgery. These findings highlight the need for further research to guide better use of this common preoperative test.
Contributors: DNW, WSB, PCA, and AL contributed to the conception and design of the study. DNW and PCA contributed to the analysis, and all authors contributed to the interpretation. DNW drafted the article; all authors revised it critically for important intellectual content and approved the final version submitted for publication. DNW is the guarantor.
Funding: DNW is supported by a clinician-scientist award from the Canadian Institutes of Health Research. DNW, WSB, and KK are supported by merit awards from the Department of Anesthesia at the University of Toronto. WSB is the R Fraser Elliot Chair of Cardiac Anesthesia at the University Health Network. PCA is supported by a career investigator award from the Heart and Stroke Foundation of Ontario. This study was supported in part by the Institute for Clinical Evaluative Sciences, which is itself supported in part by the Ontario Ministry of Health and Long-Term Care. The study sponsor had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; or preparation, review, and approval of the manuscript. The opinions, results, and conclusions are those of the authors, and no endorsement by the Ontario Ministry of Health and Long-Term Care or the Institute for Clinical Evaluative Sciences is intended or should be inferred.
Competing interests: All authors have completed the Unified Competing Interest form at http://www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any company for the submitted work; no financial relationships with any companies that might have an interest in the submitted work in the previous three years; and no non-financial interests that may be relevant to the submitted work.
Ethical approval: Sunnybrook Health Sciences Centre gave research ethics approval for the study.
Data sharing: No additional data available.
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