Following surgery for lung cancer, patients are at risk for life-threatening blood clot formation in the lungs (pulmonary embolism) or in the legs (deep vein thrombosis) — known together as venous thromboembolic events. Three studies presented during the 95th Annual American Association for Thoracic Surgery Meeting 2015 identified the high rate of occurrence for venous thromboembolic events and demonstrated the need to screen lung cancer surgery patients for clots to initiate treatment if necessary.
Yaron Shargall, MD, of McMaster University in Ontario, Canada, presented the first study entitled, “The Incidence and Burden of Venous Thromboembolism after Major Lung Resection: A Prospective Cohort Analysis.” Dr. Shargall, who is the Head of Division of Thoracic Surgery at McMaster, and colleagues conducted a prospective analysis of patients undergoing oncologic lung resection. The team was interested in the frequency of venous thromboembolic events among the 156 patients studied.
Thirty days after surgery, 12.1% of patients experienced a venous thromboembolic event, where 14 were pulmonary embolisms, three were deep vein thrombi, and one was a combination. Clots tended to form on the same side as the resected lung, which underwent either lobectomy or segmentectomy. The prevalence of clots increased the chance for mortality to 5.2%, whereas the overall mortality rate for the group was only 0.64%.
Siva Raja, MD, PhD, of Cleveland Clinic Foundation in Ohio, presented the second study entitled, “Routine VTE Screening After Pneumonectomy: You Must Look to Find.” Dr. Raja and colleagues looked at a slightly smaller group of patients (112) who underwent a pneumonectomy to remove a benign or malignant tumor. The researchers screened the patients for venous thromboembolic events and discovered that the chance of recognizing a clot increased from 3.0% to 8.9% when a screening was conducted when the patient was still in the hospital. This rate increased to 13% vs. 5.0% when a screening was conducted 30 days after the operation.
“We find that a large proportion (50%) of venous thromboembolic events occurred prior to the time of discharge, and the risk of developing symptomatic VTE remained elevated for 30 days,” commented Dr. Raja, in a news release from AATS. “It is possible that the prevalence of venous thromboembolic event may be even higher should a comprehensive serial screening program be initiated.”
Virginia R. Litle, MD of Boston University School of Medicine presented a poster detailing “Caprini Risk Assessment for Postoperative Venous Thromboembolism in Surgical Lung Cancer Patients.” She explained the Caprini Risk Assessment Model (RAM) in the news release from AATS. “The Caprini Risk Assessment Model (RAM) is used as a venous thromboembolic event risk assessment tool in other surgical specialties, including general, vascular and plastic surgery as well as gynecologic oncology,” said Dr. Litle. “In abdominal and pelvic cancer patients, the RAM helps physicians evaluate extended prophylactic use of blood thinners, but it has not been applied in thoracic surgery.”
This study was larger than the other two and evaluated 40 risk factors for blood clots in 232 patients undergoing a lung resection. Of the 5.17% of patients who experienced a venous thromboembolic event, the Caprini score was able to predict the chance for clot formation, with a higher score indicating a higher risk.
By understanding the risk for blood clots in patients and knowing how they can be predicted, lung cancer patients undergoing a surgical procedure may see fewer complications and a lower chance for morbidity if they are screening and treated for venous thromboembolic events.