Venous thromboembolism events after thoracic surgery: global steps toward prevention

Risk factors for venous thromboembolism and evaluation of the modified Caprini score in patients undergoing lung resection

Background

There is a high incidence of venous thromboembolism (VTE) after lung resection, so it is necessary to identify the risk factors for VTE in these patients. It is also important to evaluate whether the modified Caprini score can accurately assess the risk of VTE in patients after lung resection.

Methods

This retrospective study included 437 patients undergoing lung resection between July 2016 and December 2017. All patients underwent lower extremities ultrasound before and after operation to determine the presence of the newly diagnosed VTE.

Results

Forty-seven (10.8%) of the 437 patients were diagnosed with VTE after lung surgery. Multivariate logistic regression analysis showed that age (OR, 2.04; 95% CI, 1.40-2.99), duration of operation (OR, 1.51; 95% CI, 1.08-2.12), lymphocyte count (OR, 0.28; 95% CI, 0.11-0.69), and D-dimer concentration (OR, 1.55; 95% CI, 1.22-1.97) were significantly associated with VTE in lung resection patients. The cut-off values for lymphocyte count and D-dimer concentration determined using receiver operating characteristic (ROC) curve were 1.15×10⁹/L and 1.37 µg/mL respectively. The modified Caprini score divided the patients into three groups: low risk (0-4 points), moderate risk (5-8 points) and high risk (≥9 points), and the incidence of VTE was 12.3% (37/300), 7.5% (10/133) and 0% (0/4), respectively (P>0.05).

Conclusions

In this study, we identified four independent factors for VTE after lung resection patients: age, duration of operation, lymphocyte count, and D-dimer. According to the modified Caprini score, there were fewer patients in the high-risk group, and the incidence of VTE not increased with the increase of risk. Better evaluation of operation time and D-dimer may help the modified Caprini score to better assess VTE risk in these patients.

Hypercoagulability After Resection of Thoracic Malignancy: A Prospective Evaluation

BACKGROUND

Rates of venous thromboembolism are increased in thoracic malignancy; however, coagulation patterns are not established. We hypothesize that patients with esophageal and lung malignancy have similar hypercoagulable pre- and postoperative profiles as defined by rotational thromboelastometry (ROTEM).

METHODS

Prospective study was conducted in 47 patients with esophageal and lung cancer undergoing surgical resection. ROTEM evaluated pre/postoperative coagulation status.

RESULTS

Patients with thoracic malignancy were hypercoagulable by ROTEM, but not by conventional coagulation tests. Preoperative hypercoagulability was higher in lung versus esophageal cancer (64 vs. 16%, p = 0.001). Lung cancer patients that were hypercoagulable preoperatively demonstrated decreased maximum clot firmness (MCF) (p = 0.044) and increased clot time (p = 0.049) after surgical resection, suggesting reversal of hypercoagulability. Resection of esophageal cancer increased hypercoagulability (16 vs. 56%, p = 0.002) via elevated MCF (reflecting platelet activity). Hypercoagulability remained at follow-up clinic for both lung and esophageal cancer patients.

CONCLUSIONS

Hypercoagulability in patients with lung malignancies reversed following complete surgical resection, whereas hypercoagulability occurred only postoperatively in those with esophageal malignancies. In both, hypercoagulability was associated with fibrin and platelet function.

Preoperative Heparin for Lung Cancer Resection Increases Risk of Reoperation for Bleeding

Lung cancer patients are at risk for venous thromboembolism (VTE). Preoperative heparin administration may increase the risk of bleeding requiring reoperation. The purpose of this study was to evaluate preoperative heparin's effect on reoperation for bleeding. A retrospective review compared outcomes for patients undergoing pulmonary resection for primary lung cancer from January 2006 to April 2018. Preoperative heparin was administered at the discretion of the attending surgeon. Comparisons were performed between preoperative subcutaneous heparin (5000 U) and no heparin groups. A total of 3325 lung resections were reviewed, 1.4% (n = 48) required reoperation for bleeding. VTE occurred in 1.1% (n = 38). Four hundred sixty-four patients (14.0%) did not receive preoperative heparin. The preoperative heparin group had increased rates of prior thoracic surgery (5.1% [n = 146] vs 1.7% [n = 8], P < 0.001), minimally invasive approach (40.2% [n = 1150] vs 10.6% [n = 49], P < 0.001), and sublobar resections (17.7% [n = 506] vs 10.6% [n = 49], P < 0.001). There were no differences in blood loss/transfusions. Reoperation for bleeding was significantly increased in the preoperative heparin group (1.6% [n = 47] vs 0.2% [n = 1], P = 0.017). There were no differences in VTE (1.5% [n = 7] vs 1.1% [n = 31], P = 0.424). On logistic regression, preoperative heparin was independently associated with increased reoperation for bleeding (odds ratio 8.13, P = 0.039); however, preoperative heparin was not independently associated with VTE. Preoperative heparin was associated with increased reoperation for bleeding. VTE rates are low after pulmonary resection for lung cancer and are not decreased by preoperative heparin. Preoperative heparin use should be determined by risk factor stratification for VTE and reoperation for bleeding in patients undergoing lung cancer resection.