The current prospective study demonstrated that the incidence of postoperative VTE after lung resection for bronchiectasis was still substantial. 8.5% patients had a postoperative VTE. In addition, we evaluated the capacity of Caprini RAM to stratify bronchiectasis surgery patients for VTE risk. A higher Caprini score was associated with a greater likelihood of postoperative VTE events. A Caprini score of 5, used as a positive test cutoff, seemed to be most appropriate based on excellent sensitivity and specificity. Although there have been many studies on VTE after oncological lung resection and esophagectomy, few data exist on the incidence of postoperative VTE in patients undergoing surgical treatment for bronchiectasis. Only several reports have shown the incidence of postoperative VTE in patients with benign lung disease. For instance, previous studies at our center [24, 26]reported that the incidence of postoperative VTE was 7% in patients with benign lung disease. However, notably, due to the limited sample size of only 27 patients with bronchiectasis, this study did not determine a more reliable incidence of postoperative VTE in patients with bronchiectasis. Likewise, Ala-Seppälä et al. [27]analyzed the occurrence of VTE in more than 400 patients undergoing surgical intervention for pleural infections during long-term follow-up and found that the incidence of VTE was 3.8% at three months, 5.0% at one year, 8.8% at three years, and 12.4% at five years. However, the definite number of pleural infections caused by bronchiectasis is unknown. Again, the incidence of postoperative VTE in patients undergoing surgery for bronchiectasis remains unclear. In the present study, we recorded the high incidence of postoperative VTE in patients undergoing surgical procedures for bronchiectasis.

In this study, the risk of postoperative VTE in patients with bronchiectasis would increase as the caprini score increased, demonstrating the modified caprini RAM is helpful in predicting postoperative VTE. However, the risk stratification of this system may not be perfect for patients with bronchiectasis.In clinical practice, patients tended to be classified into different risk categories based on the postoperative caprini score to assist in VTE prevention. In thoracic surgery, the modified caprini scoring system (low: 0–4, moderate: 5–8; high: = 9) was widely used, which could not only stratify the risk of postoperative VTE in patients with lung and esophageal cancer, but also guide postoperative VTE prophylaxis [20, 28,29,30]. Current guideline suggested patients at low risk for VTE should receive mechanical prophylaxis without chemoprophylactic anticoagulation due to a low incidence of postoperative VTE (< 1.5%) [31]. However, there were some drawbacks in the application of the modified Caprini scoring system to bronchiectasis patients. In this study, only 1 patient had a postoperative Caprini score = 9, when the modified Caprini scoring system was applied to patients with bronchiectasis, almost all the patients were considered as low to moderate risk category postoperatively, and it was not able to distinguish the patients at truly high risk for VTE. Moreover, the risk stratification of the modified Caprini scoring system did not match the risk level of postoperative VTE in patients with bronchiectasis.76.9% (90/117) of patients with Caprini score = 4 was at low risk for VTE, the VTE incidence in the low risk category was 3.3% (3/90), nearly twice as high as 1.5% [31], suggesting that patients with Caprini score = 4 included some truly moderate to high risk patients, and receiving mechanical prophylaxis alone may not be sufficient. Further researches were needed on the appropriate Caprini scoring system for bronchiectasis patients.

The excellent predictive effect of the Caprini RAM also contributed to the diagnosis of postoperative VTE in bronchiectasis. Previous study showed that the best positive test cutoff value for VTE in lung cancer surgery patients was 9, the resultant sensitivity, specificity, accuracy, positive and negative predictive value were 83.3%, 60.5%, 61.6%, 10.3% and 98.5%, respectively [20]. For esophagectomy patients, the best positive test cutoff value was 15, the resultant sensitivity, specificity, accuracy, positive and negative predictive value were 100%, 66.7%, 71.4%, 33.3% and 100%, respectively [28]. The patients (Caprini score = the best positive test cutoff value) may benefit from enhanced prophylactic anticoagulation [20, 28]. However, unlike lung and esophageal tumor patients, the postoperative Caprini scores of almost all patients undergoing surgery for bronchiectasis were lower than 9 due to much more younger patients and absence of tumor risk factors [20, 28]. According to the ROC with Caprini scores as postoperative VTE predictor, in bronchiectasis patients undergoing lung resection, a Caprini score of 5 was set as a positive test cutoff with excellent sensitivity and specificity, high positive predictive value and negative predictive value. These patients (Caprini score = 5) should be recommended for positive VTE monitoring and prevention postoperatively. Therefore, there should be individual positive test cut-off values for different kinds of diseases to assist in postoperative VTE prevention in thoracic surgery.

There were some limitations to our study. First, our study was a single-center study and had a small sample size, thus the conclusion may be biased. Additionally, we had no prolonged follow-up for patients after discharge. The VTE risks among patients undergoing lung resection for bronchiectasis may have been underestimated in this cohort. Larger sample sizes and long-term follow-up studies were needed.