Long-term outcomes of microsurgical vs standard coronary artery bypass grafting in patients with concomitant diabetes mellitus

Abstract

Introduction. CABG outcomes are particularly complicated in patients with
diabetes mellitus due to diffuse coronary disease and smaller target artery diameters, increasing the risk of graft occlusion. The quality of the distal anastomosis, enhanced by microsurgical technique, may be critical for long-term results in this group.

Objective. To compare the long-term outcomes of microsurgical versus standard coronary artery bypass grafting (CABG) in patients with concomitant diabetes mellitus. 

Methods. A retrospective analysis included 478 diabetic patients who underwent isolated CABG between 2012 and 2022. Patients were stratified into two groups: those undergoing standard CABG (OPT, n = 186) and those undergoing microsurgical CABG (MICRO, n = 292). To mitigate selection bias, 1:1 propensity score matching was performed, yielding 167 matched pairs (n = 167 per group). The primary endpoint for long-term outcomes was freedom from major adverse cardiac and cerebrovascular events (MACCE). Secondary endpoints included overall survival and the individual components of MACCE.

Results. The microsurgical technique was associated with a statistically significant increase in freedom from MACCE compared to the standard technique (10-year freedom: 59.4 % vs 44.3 %, p = 0.012). Multivariate Cox regression identified duration of inotropic support (p = 0.006), female sex (p = 0.012), number of grafts (p = 0.003), and left ventricular end-diastolic volume (LVEDV; p = 0.007) as independent predictors of MACCE. No statistically significant difference in overall survival was observed between groups (10-year survival: 82.0 % vs 65.8 %; p = 0.060). Multivariate analysis identified female sex (p = 0.037) and number of grafts (p = 0.021) as independent factors influencing survival. Cardiac mortality was significantly lower in the MICRO group (p = 0.003). Independent predictors of cardiac mortality included female sex (p = 0.025), patient age (p = 0.034), and number of grafts (p = 0.026). While a trend towards improved freedom from repeat revascularization was noted in the MICRO group, the difference was not statistically significant (p = 0.17). No independent predictors for repeat revascularization were identified. The incidence of myocardial infarction was significantly reduced in the MICRO group (p < 0.001). On multivariate analysis, the microsurgical technique (p = 0.001), female sex (p = 0.011), cardiopulmonary bypass duration (p = 0.043), aortic crossclamp time (p = 0.046), inotropic support duration (p = 0.001), and number of grafts (p = 0.028) were independent factors associated with myocardial infarction risk.

Conclusion. In patients with diabetes mellitus, microsurgical CABG is associated with superior long-term outcomes, evidenced by significantly greater freedom from MACCE, reduced cardiac mortality, and a lower incidence of myocardial infarction compared to the standard technique.

Received 25 August 2025. Revised 10 November 2025. Accepted 23 December 2025.

Informed consent
All patients provided informed consent for the use of their medical data for scientific purposes.

Funding
The work of S. Khrushchev was supported by the Program for fundamental scientific research of the Siberian Branch of the Russian Academy of Sciences (project number FWNF-2024-0001).

Conflict of interest
The authors declare no conflict of interest.

Сontribution of the authors
Conception and study design: K.N. Kaldar, S.A. Al’sov

Data collection and analysis: K.N. Kaldar, N.M. Abilov, M.V. Okilov, T.A. Pakhmuteva Statistical analysis: S.E. Khrushchev, K.N. Kaldar

Drafting the article: K.N. Kaldar, S.A. Al’sov Critical revision of the article: D.A. Sirota, S.A. Al’sov, A.M. Chernyavski

Final approval of the version to be published: all authors