Matched Analysis A
In propensity score-Matched Analysis A the number of patients was 111 in each group, including those who had undergone any type of primary surgery (CABG only, valve only and CABG plus valve with/without other). Postoperative outcomes are shown in Table 4. The rate of the composite end-point was 21% in the redo-CABG and 17% in the redo-OPCAB groups (P = 0.25). This included in-hospital mortality (4 vs 2%, P = 0.25), AKI (14% vs 12%, P = 0.56), stroke (1% vs 1%, P = 1) and severe LCO requiring IABP (10 vs 3%, P = 0.03), all redo-CABG vs redo-OPCAB. Reopening for bleeding was 4 times higher in the redo-CABG group (4% vs 1%, P = 0.17) and the length of stay was slightly longer in the redo-CABG group (8.7 ± 5.6 vs 8.1 ± 5.6 days, P = 0.18). Peak of postoperative SCrea was 127.9 ± 59.8 µmol/l and 123.3 ± 60.5 µmol/l for redo-CABG and redo-OPCAB, respectively (P = 0.34). Figure 3A shows the Kaplan–Meier survival curves. The long-term survival was similar between groups (log-rank test: P = 0.5). Late survival at 1, 5 and 10 years was similar between groups at 94.6 vs 91%, 83.2 vs 79.8% and 65.1 vs 60.8% for redo-OPCAB vs redo-CABG, respectively. The number of graft was higher in the redo-CABG group (2.4 ± 0.8 vs 2.1 ± 0.8, P <0.01). After stepwise selection process, the multivariable logistic regression model included EuroSCORE (OR = 1.25, 95% CI: 0.99–1.59, P = 0.06) and preoperative creatinine (OR = 1.02, 95% CI 0.99–1.04, P = 0.15) as predictors of composite outcome.
Table 4 Operative outcomes in matched analysis
Matched Analysis A Matched Analysis B
Characteristic Redo-OPCAB (n = 111) Redo-CABG (n = 111) P-value Redo-OPCAB (n = 84) Redo-CABG (n = 84) P-value
In-hospital mortality (%) 2 (2) 5 (4) 0.25 0 (0.0) 4 (5) 0.13
AKI (%) 13 (12) 16 (14) 0.56 5 (6) 9 (11) 0.24
CVA (%) 1 (1) 1 (1) 1.00 0 (0) 0 (0) NA
Usage of IABP (%) 3 (3) 10 (10) 0.03 2 (2) 9 (11) 0.02
Composite outcome (%) 17 (15) 23 (21) 0.25 7 (8) 16 (19) 0.04
Reoperation for bleeding (%) 1 (1) 4 (4) 0.17 0 (0) 1 (1) 1.00
Completeness of revascularization (%) 77 (69) 91 (82) 0.02 57 (68) 60 (71) 0.60
Hospital stay 8.1 (6.2) 8.67 (5.6) 0.15 8 (5.4) 8.5 (5) 0.17
AKI: acute kidney injury (defined as peak of postoperative creatinine >% higher than preoperative value); CVA: cerebrovascular accident; IABP: intra-aortic balloon pump (either intraoperatively or postoperatively only).
Figure 3  Kaplan–Meier survival curves for redo-OPCAB and redo-CABG in the propensity score-Matched Analysis A and Matched Analysis B.