A retrospective study from a national chronic thromboembolic pulmonary hypertension (CTEPH) referral center in Turkey tracked 115 patients who underwent pulmonary endarterectomy (PEA) surgery between 2018 and 2023, comparing direct oral anticoagulants (DOACs) against traditional vitamin K antagonists (VKAs). CTEPH, a rare form of pulmonary hypertension from chronic clots, responds best to PEA, which removes organized thrombi from lung arteries to ease right heart strain. The results were published in the International Journal of Cardiology.
While VKAs have long been standard for lifelong anticoagulation, DOACs gained favor for easier use despite thin evidence in CTEPH. Researchers examined surgical specimens under microscopes to spot recent thrombi, then checked surgical times and heart function data before and after surgery.
Fresh Thrombi Three Times More Common with DOACs
Histopathology revealed recent thrombi in 26.2% of DOAC patients versus just 9.2% on VKAs (p<0.05), nearly a threefold difference. Microscopic review proved far more sensitive than visual checks during surgery, catching clots missed by the naked eye. This suggests DOACs may fail to fully prevent new clot formation in CTEPH's complex vasculopathy, where organized thrombi mix with microvascular changes. Pulmonologists and cardiac surgeons will note how these findings challenge DOAC convenience in a disease where anticoagulation choice directly impacts operability.
Surgery and Heart Function Hold Steady Across Groups
Despite more fresh thrombi in the DOAC group, surgery went smoothly with no differences in key measures like extracorporeal circulation time or cardiac arrest duration. Postoperative hemodynamics—pressure readings and heart outputs—matched between groups, showing thrombi presence did not worsen immediate surgical success. Patients recovered similarly regardless of anticoagulant, hinting that PEA's mechanical clot removal overrides anticoagulation shortcomings in the short term.
Microscopy Unlocks Hidden Clot Truths
The study's strength lay in detailed pathology, proving routine tissue analysis spots active clotting risks invisible during operations. DOAC users' higher thrombus rate raises red flags about their mechanism in CTEPH, possibly less effective against microvasculopathy than VKAs. Clinicians managing operable CTEPH now face a dilemma: stick with proven VKAs pre-surgery or risk DOAC limitations that could affect long-term vessel patency.
Rethinking Anticoagulation Before CTEPH Surgery
These results urge caution with DOACs in CTEPH, especially before PEA, and call for randomized trials to settle VKA versus DOAC debates. Pathology integration into practice could guide patient selection and timing, while multidisciplinary teams weigh thrombosis risks against bleeding concerns. For the 115 patients studied, outcomes proved solid, but the thrombus gap signals a need to revisit guidelines for this curable yet deadly condition.