Thirty-day Mortality
Thirty-day mortality was 7.1% for the whole cohort, while 100% for the acute phase (<7 days after AMI12), 21.4% for the healing phase (7–28 days), and 4.08% for the healed phase (29 days and beyond). Significant risk factors of 30-day mortality found by the univariable analysis were age, gender, infarction-surgery interval, previous cerebrovascular accident, ΔD, and ΔDR. (Table 3) Independent risk factors of 30-day mortality found by multivariable analysis corrected by 1,000 bootstrap replicates were female gender, elder age, shorter infarction-surgery interval, previous cerebrovascular accident, lower ΔD, and higher ΔDR. (Table 4)
ROC curves for Dmax and ΔDR were plotted separately to evaluate their predictive power for 30-day mortality, yielding an area under the curve (AUC) of 0.641 and 0.863 respectively. (Figure 1) The results indicated that ΔDR predicted 30-day mortality with high accuracy.
The cut-off point was picked at 0.205 mm/d by calculating the maximum of the Youden index. According to the cut-off point, the patients were divided into the low ΔDR group and the high ΔDR group. The differences in preoperative IABP implantation, EuroSCORE, preoperative critical status, CPB time, aortic clamp time, postoperative ventilation time, ICU stay, reoperation, and 30-day mortality were statistically significant between the two groups. (Table 5)