Data Analysis
Study data were collected and managed using REDCap electronic data capture tools hosted at Lenox Hill Hospital (17). REDCap (Research Electronic Data Capture) is a secure, web-based application designed to support data capture for research studies.
Observed covariates at baseline included age, gender, body mass index, diabetes mellitus, cerebrovascular disease, chronic lung disease, peripheral vascular disease, dialysis-dependent renal failure, history of prior myocardial infarction, congestive heart failure, and left ventricular ejection fraction. To control for these confounding influences, we calculated propensity scores (or the probability of assignment to HCR, CABG, or multi-vessel PCI) using multivariable logistic regression for each patient. Patients who underwent HCR were matched with patients who underwent conventional CABG and with those who had multi-vessel PCI in a 1:1 ratio through a nearest neighbor-matching algorithm. In order to exclude bad matches, we instituted a caliper of 0.2 of the standard deviation of the logit of the propensity score. The Area Under the Curve for the ROC of the propensity model 0.74. The matched sample included a total of 300 patients, evenly distributed in each group
Longitudinal outcomes and survival to 8 years was estimated using Kaplan-Meier analysis and Cox proportional hazard regression. Patient characteristics and outcomes were compared using chi-square, Fisher’s exact test, Student’s t-test, or Wilcoxon-Mann-Whitney test, as appropriate. A chi-square test was used for categorical variables where the expected value for each cell was 5 or higher; if this assumption was not met, then Fisher’s exact test was used. A p value of less than 0.05 was considered to be statistically significant. Statistical analyses were performed with the IBM Statistical Package for the Social Sciences (SPSS) for Windows, version 22.0 (IBM Corporation, Armonk, NY, USA).
Mean (± SEM) follow-up was 7.14 ± 0.12 years for all patients. All-cause mortality up to a maximum of 8 years was obtained by querying the National Death Index (NDI) to determine dates of death up to December 31, 2016. Short-term outcomes, such as length of hospital stay, peri-procedural stroke, myocardial infarction (MI) or new-onset renal failure was evaluated via a retrospective chart review on our hospital systems electronic medical records. The long-term follow up for repeat revascularization, myocardial infarction and target vessel revascularization was achieved through a chart review of our hospital system and our referring hospital systems electronic medical records. The majority of patients had follow up greater than 1 year, however there were patients (18 total) that we were unable to find proper follow-up after hospital discharge.