Time-to-Referral, Use, and Efficacy of Cardiac Rehabilitation After Heart Transplantation

Background: Timely access, adherence, and efficacy of cardiac rehabilitation programs (CRP) are important given the potential to mitigate/reverse the side-effects of immunosuppressive medications, weight gain, and cardiovascular deconditioning that place heart transplant (HT) recipients at increased cardiovascular risk. However, there is a dearth of information on use and efficacy of CRPs. Therefore, we examined process indicators (time-to-referral and correlates, program adherence) and clinical outcome indicators (functional capacity (VO2peak), anthropometrics) of CR post-HT compared to post-coronary artery bypass graft (CABG). Methods: Baseline and 6 month exercise stress test results, and anthropometrics were examined retrospectively among consecutively enrolled post-HT and age-and sex-matched CABG patients. Time-to-referral/program entry, attendance and completion rates were also measured. Results: HT (n=43) and CABG patients were referred 24.9±48.9 and 2.1±3.6 months respectively, following surgery(p=0.003). Once referred, there was no difference in elapsed-time to program entry (p=0.2). There was a positive relationship between time-to-referral and baseline waist circumference(r=0.5,p=0.001), body mass index (r=0.5,p=0.002), hip circumference (r=0.4,p=0.008), and body fat percentage (r=0.4,p=0.03) in HT. HT and CABG patients had similar rates of CRP dropout (27.9% vs. 37.2%respectively,p=0.4).There was improvement in VO2peakfor HT (2.4±4.2 mLkg-1min-1,p=0.02) and CABG (5.5±5.4 mLkg-1min-1,p<0.001), but was greater for CABG(p=0.04). Anthropometric measures remained stable for both cohorts (p>0.05). Conclusions: There is a lengthy delay in time-from-HT to CRP referral, though once referred, gain significant benefit in functional capacity. The appropriateness of this wait needs to be elucidated, however it appears that longer wait times are associated with adverse effects on body composition.