Prospective Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Cardiol. Nov 26, 2016; 8(11): 676-683
Published online Nov 26, 2016. doi: 10.4330/wjc.v8.i11.676
Outcomes and long-term survival of coronary artery surgery: The controversial role of opium as risk marker
Mahdi Najafi, Leila Jahangiry, Seyedeh Hamideh Mortazavi, Arash Jalali, Abbasali Karimi, Ali Bozorgi
Mahdi Najafi, Department of Anesthesiology, Tehran Heart Center, Tehran University of Medical Sciences, Tehran 1411713138, Iran
Mahdi Najafi, Seyedeh Hamideh Mortazavi, Arash Jalali, Department of Research, Tehran Heart Center, Tehran University of Medical Sciences, Tehran 1411713138, Iran
Leila Jahangiry, Department of Health Education and Promotion, School of Public Health, Tabriz University of Medical Sciences, Tabriz 5165665931, Iran
Abbasali Karimi, Department of Cardiothoracic Surgery, Tehran Heart Center, Tehran University of Medical Sciences, Tehran 1411713138, Iran
Ali Bozorgi, Department of Cardiology, Tehran Heart Center, Tehran University of Medical Sciences, Tehran 1411713138, Iran
Author contributions: Najafi M designed the study; Najafi M, Jahangiry L, Karimi A, Bozorgi A performed the research; Mortazavi SH and Jalali A analysed the data; Najafi M and Mortazavi SH wrote the paper; Najafi M revised the manuscript for final submission.
Institutional review board statement: The study was reviewed and approved by the Tehran Heart Center Institutional Review Board.
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: The authors declare no conflict-of-interest.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Mahdi Najafi, MD, Associate Professor, Department of Anesthesiology, Tehran Heart Center, Tehran University of Medical Sciences, North Kargar Street, Tehran 1411713138, Iran. najafik@sina.tums.ac.ir
Telephone: +98-21-88029674 Fax: +98-21-88029731
Received: June 14, 2016
Peer-review started: June 17, 2016
First decision: July 27, 2016
Revised: August 16, 2016
Accepted: September 7, 2016
Article in press: September 8, 2016
Published online: November 26, 2016
Abstract
AIM

To study survival in isolated coronary artery bypass graft (CABG) patients and to evaluate the impact of preoperative chronic opium consumption on long-term outcome.

METHODS

Cohort of 566 isolated CABG patients as Tehran Heart Center cardiac output measurement was conducted. Daily evaluation until discharge as well as 4- and 12-mo and 6.5-year follow-up information for survival status were fulfilled for all patients. Long-term 6.5-year overall and opium-stratified survival, adjusted survival curves based on opium consumption as well as possible predictors of all-cause mortality using multiple cox regression were determined by statistical analysis.

RESULTS

Six point five-year overall survival was 91.8%; 86.6% in opium consumers and 92.7% in non-opium consumers (P = 0.035). Patients with positive history of opium consumption significantly tended to have lower ejection fraction (EF), higher creatinine level and higher prevalence of myocardial infarction. Multiple predictors of all-cause mortality included age, body mass index, EF, diabetes mellitus and cerebrovascular accident. The hazard ratio (HR) of 2.09 for the risk of mortality in opium addicted patients with a borderline P value (P = 0.052) was calculated in this model. Further adjustment with stratification based on smoking and opium addiction reduced the HR to 1.20 (P = 0.355).

CONCLUSION

Simultaneous impact of smoking as a confounding variable in most of the patients prevents from definitive judgment on the role of opium as an independent contributing factor in worse long-term survival of CABG patients in addition to advanced age, low EF, diabetes mellitus and cerebrovascular accident. Meanwhile, our findings do not confirm any cardio protective role for opium to improve outcome in coronary patients with the history of smoking. Further studies are needed to clarify pure effect of opium and warrant the aforementioned findings.

Keywords: Coronary artery bypass, Outcomes, Survival analysis, Opium, Hazards models

Core tip: A significant percentage of coronary artery disease patients undergo cardiac surgery so defining outcome predictors is essential for risk calculation and is necessary for estimation of resource utilization and provision of services. Employing global knowledge on this issue is not justified without adjustment for regional specifications and needs. This study aimed at clarifying the role of opium addiction in predicting long-term mortality of coronary artery bypass graft surgery in addition to advanced age, low ejection fraction, diabetes mellitus and cerebrovascular accident.