3.2.2. Secondary outcomes: early and long-term mortality, need of interventional procedures and surgical re-interventions
In all 32 studies included in the meta-analysis only 6 early deaths were reported among 1191 patients. Pooled prevalence of early mortality after CABG was 0.28% (95% CI: 0.00-0.73%, I²=0%, tau²=0, Supplementary Figure 5).
26 studies reported interventional procedures and surgical re-interventions rates: 63/1108 and 56/1108 patients underwent interventional procedures and surgical re-interventions at follow-up (mean 110.35 months, 95% CI: 28.50-264.00 months), respectively. Pooled prevalence of interventional procedures was 3.97% (95% CI: 1.91-6.02%, I²=60%, tau²=0.0008, Supplementary Figure 6). Across the studies that reported interventional procedures, high heterogeneity demonstrated elevated variability across the included studies.
Pooled prevalence of surgical re-interventions was 3.47% (95% CI: 2.26-4.68%, I²=5%, tau²<0.0001, Supplementary Figure 7).
Patients treated with arterial, venous and mixed (arterial plus second venous graft) CABG were compared to assess long-term mortality. 8 arm level papers out of 32 studies were included to perform the network meta-analysis [31, 34, 39, 41-43, 49, 53]. Mean follow-up across studies for long-term mortality was 142.56 months (follow-up: min 48 – max 264 months). Survival at follow-up after arterial, venous and mixed CABG are 99.07±2.27%, 83.33%±28.87% and 99.87±0.33%, respectively. The network model, trace plot and density plot for long-term mortality are shown in Supplementary Figures 8 and 9. Summary results are shown in Figure 4A, while rank probability analysis are demonstrated in Figure 4B.
The efficacy of different treatments using HR and corresponding 95% CrI is displayed in Supplementary Figure 10. Pairwise comparisons at follow-up are shown in Supplementary Figure 11 A-C. There is a lack of evidence to suggest inconsistency within the network model (Supplementary Figure 12). Briefly, mixed CABG (HR 0.03, 95% CrI: 0.00-0.30) and arterial CABG (HR 0.13, 95% CrI: 0.00-1.78) showed reduced long-term mortality compared with venous CABG.
More in deep, focusing the comparison between long-term mortality for Arterial CABG vs Mixed CABG we are faced with 58 single CABG out of a total of 133 cases (43.6%) in which at least one arterial conduit has been employed(Supplementary Figure 11C) [34,39,41-42,49]. It appears that the use of arterial conduit, even better if applied in a multiple CABG setting, provides long-term mortality benefit. These findings need to be confirmed in future studies.