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Abstract
Background In patients with ischaemic left ventricular dysfunction, coronary artery bypass surgery (CABG) may decrease mortality, but it is not known whether CABG improves functional capacity.
Objective To determine whether CABG compared with medical therapy alone (MED) increases 6 min walk distance in patients with ischaemic left ventricular dysfunction and coronary artery disease amenable to revascularisation.
Methods The Surgical Treatment in Ischemic Heart disease trial randomised 1212 patients with ischaemic left ventricular dysfunction to CABG or MED. A 6 min walk distance test was performed both at baseline and at least one follow-up assessment at 4, 12, 24 and/or 36 months in 409 patients randomised to CABG and 466 to MED. Change in 6 min walk distance between baseline and follow-up were compared by treatment allocation.
Results 6 min walk distance at baseline for CABG was mean 340±117 m and for MED 339±118 m. Change in walk distance from baseline was similar for CABG and MED groups at 4 months (mean +38 vs +28 m), 12 months (+47 vs +36 m), 24 months (+31 vs +34 m) and 36 months (−7 vs +7 m), P>0.10 for all. Change in walk distance between CABG and MED groups over all assessments was also similar after adjusting for covariates and imputation for missing values (+8 m, 95% CI −7 to 23 m, P=0.29). Results were consistent for subgroups defined by angina, New York Heart Association class ≥3, left ventricular ejection fraction, baseline walk distance and geographic region.
Conclusion In patients with ischaemic left ventricular dysfunction CABG compared with MED alone is known to reduce mortality but is unlikely to result in a clinically significant improvement in functional capacity.
Trial registration number NCT00023595.
- coronary artery bypass grafting
- ischemic cardiomyopathy
- exercise capacity
- six-minute walk distance
- clinical trial
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Footnotes
Contributors RAHS drafted the manuscript. All authors contributed to critical review of the manuscript and approved it for submission.
Funding This work was supported by grants U01HL69015, U01HL59013 and R01HL105853 from the National Institutes of Health/National Heart, Lung, and Blood Institute (Clinical Trial Registration – Unique Identifier: NCT00023595).
Disclaimer This work is solely the responsibility of the authors and does not necessarily represent the official views of the NIH or NHLBI.
Competing interests JGHC: Medtronic advisory board. HDW: grants and non-financial support from GlaxoSmithKline during the conduct of the study; grants from Sanofi Aventis, Eli Lilly and Company, National Institutes of Health, Merck Sharpe & Dohm, Omthera Pharmaceuticals, Pfizer New Zealand, Intarcia Therapeutics Inc, Elsai Inc, DalGenE Products and Services; grants and personal fees from AstraZeneca, outside the submitted work. EJV: research grants from NHLBI, Alnylam Pharmaceuticals, Amgen, Novartis Pharmaceutical Corp and Pfizer; consulting services for Amgen, Merck & Co and Novartis Pharmaceutical Corp; and speakers bureau honoraria from Expert Exchange.
Ethics approval The study protocol was approved by each site’s institutional review board or ethics committee.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.