Effectiveness and Safety of Early Initiation of Poststernotomy Cardiac Rehabilitation Exercise Training: The SCAR Randomized Clinical Trial

Abstract

Importance: Guidelines recommend that cardiac rehabilitation (CR) exercise training should not start until 6 weeks after sternotomy, although this is not evidence based. Limited data suggest that starting earlier is not detrimental, but clinical trials are needed.

Objective: To compare the effectiveness and safety of CR exercise training started either 2 weeks (early CR) or 6 weeks (usual-care CR) after sternotomy.

Design, setting, and participants: This was an assessor-blind, noninferiority, parallel-group, randomized clinical trial that conducted participant recruitment from June 12, 2017, to March 17, 2020. Participants were consecutive cardiac surgery sternotomy patients recruited from 2 outpatient National Health Service rehabilitation centers: University Hospital, Coventry, UK, and Hospital of St Cross, Rugby, UK.

Interventions: Participants were randomly assigned to 8 weeks of twice-weekly supervised CR exercise training starting either 2 weeks (early CR) or 6 weeks (usual-care CR) after sternotomy. Exercise training adhered to existing guidelines, including functional strength and cardiovascular components.

Main outcomes and measures: Outcomes were assessed at baseline (inpatient after surgery), after CR (10 or 14 weeks after sternotomy), and 12 months after randomization. The primary outcome was the change in 6-minute walk test distance from baseline to after CR. Secondary outcomes included safety, functional fitness, and quality of life.

Results: A total of 158 participants (mean [SD] age, 63 [11.5] years, 133 male patients [84.2%]) were randomly assigned to study groups; 118 patients (usual-care CR, 61 [51.7%]; early CR, 57 [48.3%]) were included in the primary analysis. Early CR was not inferior to usual-care CR (noninferiority margin, 35 m); the mean change in 6-minute walk distance from baseline to after CR was 28 m greater in the early CR group (95% CI, -11 to 66; P = .16). Mean differences for secondary outcomes were not statistically significant, indicating noninferiority of early CR. There were 46 vs 58 adverse events and 14 vs 18 serious adverse events in usual-care CR and early CR, respectively. There was no difference between the groups in the likelihood of participants having an adverse or serious adverse event.

Conclusions and relevance: Starting exercise training from 2 weeks after sternotomy was as effective as starting 6 weeks after sternotomy for improving 6-minute walk distance. With appropriate precautions, clinicians and CR professionals can consider starting exercise training as early as 2 weeks after sternotomy.

Trial registration: ClinicalTrials.gov Identifier: NCT03223558.

Conflict of interest statement

Conflict of Interest Disclosures: Drs Ennis and McGregor reported serving as directors of Atrium Health Ltd, a provider of rehabilitation services for the National Health Service. Drs Ennis, Banerjee, and McGregor reported receiving grants from the Medical & Life Sciences Research Fund and the Jeremy Pilcher Memorial Fund during the conduct of the study. Drs Banerjee and McGregor reported receiving grants from the National Institute for Health Research and the British Heart Foundation. No other disclosures were reported.

Figures

Figure 1.. Consolidated Standards of Reporting Trials (CONSORT) Diagram

CR indicates cardiac rehabilitation.

Figure 2.. Primary Outcome: Change in 6-Minute Walk Test Distance From Baseline to After Rehabilitation and 12 Months of Follow-up

CR indicates cardiac rehabilitation.