Higher Syntax Score as a Predictive Factor of Mortality Following Coronary Bypass Surgery

Background and Purpose: Aim of this retrospective study was to evaluate association between the high preoperative SYNTAX score and mortality in primary coronary bypass surgery (CABG).

Methods: Consecutive 484 patients undergoing primary isolated CABG from period of January 2007 to December 2014 were retrospectively assessed. SYNTAX Score was calculated and investigation groups were set as proposed by SYNTAX investigators. In retrospective way the influence of SYNTAX Score on in hospital, on follow up mortality was evaluated.

Results: Total 484 patients were included, 15.5% were females (n = 75) and mean age was 65.2 ± 9.13 years. Preoperative risk factors were as follows; diabetes mellitus in 40.1% (n = 149 out of 484), peripheral vascular disease in 18.2% (n = 88 out of 484), smokers were 33.5% (162 out of 484) and dyslipidemia in 79.33% (n = 384 out of 484) of cases.Preoperative mean SYNTAX Score re was 35.4 ± 9.55. According to the score tercile three groups were identified: in low SYNTAX score (0–22) were 9.71% (n = 47 out of 484) cases, in intermediate score (23–33) 29.13% (n = 141 out of 484) and high score (>33) were 61.16% (n = 296 out of 484) of cases. The statistical analysis revealed that the high SYNTAX Score was predictive factor for in hospital as well for follow-up mortality. In hospital mortality was 2.27% (n = 11 out of 484), and according to three groups it was; 0.2% in low (n = 1 out of 484), 0.2% (n = 1 out of 484) in intermediate and 1.85% (n = 9 out of 484) in high SYNTAX group, it was significantly higher as compared with the low and intermediate group (p< 0.05).Follow up mortality was 5.49% (n = 26 out of 473) and according to three groups the distribution was as follows; 0.42% (n = 2 out of 473) in low, 0.84% (n = 4 out of 473) in intermediate and 4.22% of cases (n = 20 out of 473) in high SYNTAX score class. Mortality in high group was significantly higher as compared with the low and intermediate group (p< 0.05).

Conclusion: According to our results a higher SYNTAX Score was associated with a higher incidence of in-hospital and late mortality following the primary coronary artery bypass surgery. As thus, our results are not in line with SYNTAX investigator statement, where the high score is not identified as predictive factor for mortality in primary CABG population. It seems that the SYNTAX score is not suitable predictor for short as well long term survival in patients with complex coronary surgical approach.