Early and Long-Term Outcomes of Minimally Invasive Direct Coronary Artery Bypass in Elderly Patients: A Propensity Score-Matched Analysis

Background: Advancing age is incorporated as a strong risk variable in EuroSCORE II and is consistently associated with adverse outcomes after conventional coronary artery bypass grafting (CABG). Whether minimally invasive direct coronary artery bypass (MIDCAB)—which avoids both sternotomy and cardiopulmonary bypass—modifies this age-related risk in patients with single-vessel or LAD-predominant coronary artery disease remains insufficiently characterised. Methods: We retrospectively analysed 350 consecutive patients who underwent MIDCAB at Hannover Medical School between July 1999 and April 2025 (follow-up to April 2025). Elderly patients (age ≥70 years; n = 117) were compared with younger patients (age <70 years; n = 233) before and after 1:1 propensity score matching using greedy nearest-neighbour matching with a caliper of 0.2 × SD of the logit propensity score; age was excluded from the propensity model as it represented the exposure variable. A pre-specified sensitivity propensity model that additionally excluded EuroSCORE II (because EuroSCORE II contains an age component) was also evaluated. The primary endpoint was all-cause long-term mortality; secondary endpoints included perioperative complications and in-hospital outcomes. Long-term survival was assessed by Kaplan–Meier analysis and multivariable Cox proportional hazards regression, with a pre-specified parsimonious Cox model (age, LVEF, renal impairment) and cluster-robust standard errors on matched-pair identifiers. Results: Matching produced 109 pairs with excellent covariate balance (all standardized mean differences < 0.20). MIDCAB was completed without intraoperative conversion in all patients. No 30-day mortality, perioperative stroke, or new postoperative dialysis was observed in either age stratum (Clopper–Pearson 95% CI 0.00–3.33% for each zero-event outcome). Perioperative complications—including new-onset atrial fibrillation, re-exploration for bleeding, and intensive care unit and hospital length of stay—did not differ significantly between elderly and younger patients in the matched cohort (Newcombe 95% CI for risk differences all crossing zero; McNemar’s exact tests non-significant for all matched-pair binary endpoints; Hodges–Lehmann median difference for hospital length of stay +1.0 day, bootstrap 95% CI 0.0–1.0 days). At a median follow-up of 19.0 years (IQR 11.5–24.3; reverse Kaplan–Meier potential median 19.7 years), all-cause mortality was higher in the elderly (20.2% vs. 5.5%, p = 0.002; log-rank p = 0.001; exact McNemar’s p = 0.0025 for the matched-pair mortality endpoint). After multivariable adjustment, elderly age (≥70 years) was independently associated with long-term mortality (adjusted hazard ratio 4.48, 95% CI 1.79–11.20, p = 0.001), as was EuroSCORE II (HR 2.40 per unit, p = 0.034); a pre-specified parsimonious model (age, LVEF, renal impairment) with pair-cluster robust standard errors yielded an essentially identical adjusted HR for elderly age of 4.08 (95% CI 1.65–10.04, p = 0.002), and a sensitivity propensity model without EuroSCORE II yielded HR 3.95 (95% CI 1.68–9.29, p = 0.002). Conclusions: In this propensity-matched analysis with a median follow-up of ~19 years, MIDCAB was associated with excellent observed perioperative outcomes in appropriately selected elderly patients (no 30-day mortality, stroke, or new dialysis observed; upper 95% CI 3.3%) and no evidence of an excess of major in-hospital complications compared with younger patients within the statistical resolution of the cohort. The long-term mortality excess in the elderly is consistent with age-related life-expectancy curves in the source population; cause-specific mortality was not available in this cohort. External benchmarks from large MIDCAB cohorts in which long-term survival approximates that of the age-matched general population support this interpretation indirectly. These findings support MIDCAB as a feasible revascularization strategy associated with favourable observed early outcomes and long-term survival consistent with published MIDCAB literature, in appropriately selected elderly patients with single-vessel or LAD-predominant coronary artery disease treated at experienced centres.