Venous Thromboembolism Following Craniotomy or Stereotactic Biopsy for Brain Tumors: Incidence, Timing, and Exploratory Risk Stratification
This study of 588 patients undergoing intracranial tumor surgery found a 90-day venous thromboembolism incidence of 11.9% and identified history of DVT, biopsy procedure, prolonged ICU stay, and mechanical ventilation as independent risk factors, enabling the development of a simplified four-point score to stratify postoperative VTE risk.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
When the brain is under attack by a tumor, surgeons often need to remove the growth or take a small sample to understand what they are dealing with. These procedures, whether a large opening of the skull or a precise needle biopsy, are life-saving, but they come with a hidden danger that lingers long after the patient leaves the hospital. The body's natural response to injury and the stress of cancer can sometimes cause blood to thicken and clot inside the veins. If these clots break loose, they can travel to the lungs, causing a sudden and potentially fatal blockage known as a pulmonary embolism. Doctors have long known this risk exists, but they have struggled to know exactly when it is most likely to happen and which patients are most vulnerable. Because treating these clots with blood-thinning medication carries its own danger of causing bleeding inside the brain, surgeons must walk a tightrope, trying to prevent clots without causing a hemorrhage. Without clear data on when these events typically occur, it has been difficult to decide how long to keep patients on protective measures or how closely to watch them after they go home.
To clear up this uncertainty, a team of researchers at Allegheny Health Network and Drexel University looked back at the records of nearly six hundred patients who had undergone surgery for brain tumors between 2016 and 2022. They focused on a specific window of time: the first ninety days after the operation. Their goal was not just to count how many people developed clots, but to map out exactly when these events happened and to find simple signs that could predict who was at risk. They examined patients who had both major tumor removals and smaller biopsies, tracking them until they either developed a clot, passed away, or completed their three-month follow-up. By treating death as a separate event that stopped the clock for the study, they could get a precise picture of the clot risk without it being skewed by patients who died from other causes.
The results revealed that the danger of blood clots is far more persistent than many might expect. Nearly twelve percent of the patients developed a clot within those first ninety days. While some clots appeared quickly, the timing of the events showed a surprising pattern. The median time for a clot to form in the leg was twenty-one days after surgery, and for a clot to reach the lungs, it took even longer, with a median of thirty-seven days. This means that for a significant number of patients, the risk does not disappear once the initial hospital stay is over. In fact, the number of new cases continued to climb steadily from the first month all the way to the third month, suggesting that the body remains in a vulnerable state for much longer than the immediate recovery period.
The researchers also identified specific factors that made certain patients more likely to develop these clots. The strongest warning sign was a history of having a blood clot before the surgery. Other clear indicators included spending two or more days in the intensive care unit, needing a machine to help with breathing after the operation, or undergoing a biopsy rather than a full tumor removal. Interestingly, the type of tumor itself—whether it was cancerous or not—did not independently predict the risk in this group, suggesting that the patient's overall condition and the stress of the procedure matter more than the specific diagnosis. The team also noted that patients who had recently received chemotherapy or radiation therapy were at higher risk, likely because these treatments can make the blood more prone to clotting.
Using these findings, the team created a simple scoring system to help doctors estimate a patient's risk. They assigned one point for each of the four main risk factors: a past history of clots, a long stay in intensive care, recent cancer treatment, and undergoing a biopsy. A patient with no points had a relatively low chance of developing a clot, while those with three or more points faced a significantly higher risk, with nearly half of that small group developing an event within ninety days. While the system is not perfect and requires further testing to confirm its accuracy, it offers a practical way to use information that is already available in a patient's chart. The study concludes that because these dangerous clots can form weeks after surgery, doctors and patients should remain vigilant long after the hospital discharge, keeping a close watch on those with the highest risk factors to catch any warning signs early.
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