Pituitary surgery can increase risk of blood clots forming in veins
Older age, high blood pressure, larger tumor sizes are risk factors, study finds
Surgery to remove pituitary tumors, the first-line treatment for Cushing’s disease, can increase the risk of venous thromboembolism (VTE), or blood clot formation in veins, especially within a week of the procedure, according to a new study.
Identified risk factors for post-surgical VTE include older age, high blood pressure, larger tumor sizes, and a history of VTE.
“Our findings also support that … screening for [blood clot formation] may be valuable in this population,” researchers wrote.
The study, “Symptomatic venous thromboembolism after transsphenoidal surgery in Cushing’s disease: incidence and risk factors,” was published in the journal Pituitary.
Pituitary surgery is first-line treatment for disease
Pituitary adenomas are benign tumors in the pituitary gland, a pea-sized gland in the brain that produces and releases various signaling molecules to coordinate the function of several organs.
In some people, pituitary adenomas produce large amounts of a signaling molecule called adrenocorticotropic hormone, which triggers the adrenal glands, sitting above the kidneys, to produce too much cortisol. Over time, high levels of cortisol in the body give rise to symptoms of Cushing’s disease.
In other people, benign tumors called non-functioning pituitary adenomas, or NFPAs, don’t produce and release active hormones, but can still disrupt pituitary function or cause other health problems.
Transsphenoidal surgery, or TSS, is a procedure used to remove pituitary adenomas and is the first-line treatment for Cushing’s disease.
With any surgical procedure, there’s an increased risk of VTE. This encompasses deep vein thrombosis, or when a blood clot forms in a deep vein, most commonly in the legs, and pulmonary embolism, which usually happens when a blood clot that forms in a deep vein breaks off and travels to the lungs.
People with high levels of cortisol in the body, such as those living with Cushing’s disease, have a higher risk of VTE, with or without surgery.
A team at Harvard Medical School in Massachusetts reviewed medical records to determine the incidence of postoperative VTE happening within 90 days of TSS in Cushing’s disease patients and to identify associated risk factors.
“By addressing these knowledge gaps, we hope to inform clinical strategies for VTE prevention and management in this high-risk population,” the researchers wrote.
VTE diagnosed within week of surgery in 5 of 6 Cushing’s patients
The team examined the medical records of 315 adults diagnosed with Cushing’s disease, ages 32 to 54, as well as those of another 559 NFPA patients, ages 47 to 68, who served as a control group. Compared with those with NFPAs, Cushing’s patients were significantly younger and more often women. They also had a higher body mass index, which is a measure of body fat content, and faster blood-clotting times.
In the first 90 days after TSS, six Cushing’s patients (1.9%) developed VTE, consisting of four deep vein thromboses and two pulmonary embolisms. In comparison, four NFPA patients (0.7%) developed VTE, including three deep vein thromboses and one pulmonary embolism. The difference in VTE incidence between the two groups was not statistically significant.
However, VTE was diagnosed within the first week after surgery in five of the six Cushing’s patients. This was not seen in any of the NFPA patients. The sixth Cushing’s patient received a VTE diagnosis 21 days after surgery, whereas all NFPA patients were diagnosed with VTE between 11 and 60 days after TSS.
“These findings suggest that patients with [Cushing’s] may be more vulnerable to VTE in the early post-TSS period compared to those with NFPAs,” the team wrote.
Among those younger than 70, the incidence of VTE within 90 days of TSS was 10 times higher in Cushing’s than in NFPA patients (2.0% vs. 0.2%).
Patients with [Cushing’s] and history of VTE should be looked at as high-risk group in the preoperative setting.
In a risk analysis, Cushing’s patients who developed VTE after surgery tended to be older and have higher blood pressure, larger tumors, and higher rates of past VTEs than those without VTE.
“Patients with [Cushing’s] and history of VTE should be looked at as high-risk group in the preoperative setting,” the researchers wrote. “To our knowledge, this is the first report to suggest a potential association between tumor size and VTE occurrence in [Cushing’s].”
Of the 18 Cushing’s patients with a history of VTE, three (16%) developed post-TSS VTE. None of those who received anti-blood-clotting medication before surgery developed postoperative VTE.
Finally, none of the Cushing’s patients, with or without VTE, experienced major surgical complications, and three out of four (73.3%), including four of the six who developed VTE, achieved disease remission with TSS.
“Patients with [Cushing’s disease] may have an increased risk of VTE, including symptomatic [pulmonary embolism], in the early postoperative setting,” the researchers wrote. “Further research is needed to better define independent risk factors for early VTE and identify those patients who may benefit from [VTE screening before, during, and after surgery] and [preventive treatment].”
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