During the study period, 125 patients were diagnosed with pulmonary embolism within 90 days after non-cardiac surgery. 24 patients were excluded because they didn’t meet our criteria for hematological disease(2 cases), received blood transfusion within 1 month preoperatively(13 cases), infection(2 cases), received immunosuppressive therapy within 1 month preoperatively(1 case) and missing data(6 cases). Finally, 101 patients with PAPE following non-cardiac surgery met our inclusion criteria and were included in this study, which including 41 males and 60 females, and the mean age was 62.23 years(range:23-95years). The demographic data and clinical data of deaths and survivors were listed in Table 1
Prognostic factors of PAPE
24 patients died within 30 days, which corresponding to 30-days mortality of 23.8%. There were no significant differences in term of age, gender, BMI, smoking history, drinking history, surgical type and ASA level (All P value＞0.05). There were no significant differences in term of hypertension, diabetes, respiratory diseases, coronary heart disease, arrhythmia, history of stroke and renal failure (All P value＞0.05). Baseline and comorbidities of patients were shown in Table 1. Preoperative laboratory parameters were presented in Table 2. The value of NLR, neutrophil and creatinine were significantly higher in deaths than in survivors with PAPE (All P value <0.05), and the value of albumin was significantly lower in deaths than survivors after PAPE (P=0.008). There were no significant differences in other terms included in our research (Table 2).
To further confirm the independent risk factors of mortality after PAPE, the multivariate logistic analysis was performed. The, NLR, MLR, WBC, Neutrophil, Lymphocyte, Creatinine, and Albumin (All P value＜0.05) were included in the multivariate analysis, and the results indicated that both NLR and albumin are independent predictors for 30-days mortality in patients with PAPE. The probability of death increased about 17.1% (OR=1.171, 95 % CI: 1.073–1.277, P=0.000) with one unit of increase of NLR, and the probability of death decreased about 15.4% (OR=0.846, 95 % CI: 0.762c–0.939, P=0.002) with one unit of increase of albumin. (Table 3). Besides, the results indicated that Creatinine, MLR, Neutrophil, Lymphocyte and WBC were no longer the independent predictors in multivariate analysis (All P value>0.05).
Development of a nomogram
Based on the independent predictors, a nomogram was established to predict the 30 days mortality in PAPE patients(Figure 1). The AUC of nomogram was 0.888(95%CI:0.812-0.964), which was significantly higher than any single predictors(P value<0.05)(Table 4 and Figure 2). Moreover, the calibration curve was shown in Figure 2A, and the results indicated that the prediction by nomogram are highly consistent with the actual observations. In addition, the DCA indicated that if the threshold probability of a patient and a doctor between 5% to 75%, this nomogram to predict 30-days mortality more benefit than the scheme.