Abstract:

Objective To analyze the risk factors of lower extremities deep vein thrombosis after thoracoscopic surgery in elderly patients with lung cancer, establish a nomogram prediction model and conduct internal verification. Methods A total of 183 elderly patients with lung cancer who underwent thoracoscopic radical resection in Nanchong Central Hospital from February 2018 to February 2022 were selected as the study subjects. According to the presence or absence of deep venous thrombosis of the lower extremities within one month after operation, the patients were divided into lower extremities deep venous thrombosis group （n=61） and non-deep lower extremities venous thrombosis group （n=122）. Univariate and multivariate analyses of deep venous thrombosis of lower extremities after thoracoscopic surgery for lung cancer in the elderly were performed, and a nomogram prediction model was constructed according to the multivariate analysis results, and the model was verified. Results There were statistically significant differences in smoking history （χ²=13.40, P<0.001）, preoperative chemotherapy （χ²=8.79, P=0.003）, surgical method （χ²=7.97, P=0.005）, operation time （t=7.23, P<0.001）, postoperative bed rest time （t=10.40, P<0.001）, combined with diabetes （χ²=6.37, P=0.012）, combined with hyperlipidemia （χ²=9.58, P=0.002）, preoperative D-dimer （t=13.08, P<0.001）, preoperative fibrinogen （t=5.84, P<0.001） and preoperative platelet count （t=7.01, P<0.001） between the lower extremity deep venous thrombosis group and the non-lower extremity deep venous thrombosis group. The results of multivariate logistic regression analysis showed that preoperative chemotherapy （OR=2.45, 95%CI： 1.05-5.71, P=0.038）, surgical method （OR=2.55, 95%CI： 1.14-5.73, P=0.023）, postoperative bed rest time （OR=1.50, 95%CI： 1.24-1.81, P<0.001）, combined with diabetes （OR=3.60, 95%CI： 1.05-12.33, P=0.042）, and preoperative D-dimer （OR=1.01, 95%CI： 1.01-1.01, P<0.001） were all independent risk factors for lower extremity deep vein thrombosis in elderly patients with lung cancer after thoracoscopic surgery. The C-index of nomogram for predicting lower extremity deep vein thrombosis-related factors was 0.86 （95%CI： 0.81-0.93）. The calibration curve showed that the model had a good correlation in predicting lower extremities deep venous thrombosis. Conclusion Preoperative chemotherapy, surgical method, postoperative bed rest time, combined with diabetes, and postoperative D-dimer level are influence factors for lower extremity deep vein thrombosis in elderly patients with lung cancer after thoracoscopic surgery. The nomogram prediction model established in this study has high accuracy and discrimination for the prediction of lower extremity deep vein thrombosis in elderly patients with lung cancer after thoracoscopic surgery.

Key words: Lung neoplasms, Aged, Thoracoscopy, Venous thrombosis, Risk factors