Beyond Bleeding: Underrecognized Thrombotic Complications in Acute Promyelocytic Leukemia - A Single-Center Experience from the GCC Region.

BackgroundThrombosis remains a clinically important complication of acute promyelocytic leukemia (APL), coexisting with the prototypical hemorrhagic diathesis. Data from Gulf Cooperation Council (GCC) populations are limited in addition to data specifically about thrombosis, which is heterogenous in general.ObjectivesTo describe the incidence, clinical characteristics, treatment, and outcomes of thrombotic events in patients with APL treated at a tertiary center in the GCC.MethodsWe conducted a retrospective cohort study of 75 consecutive patients with newly diagnosed APL managed at a single tertiary center. Baseline demographic variables (age, sex, regional background), hematologic parameters (hemoglobin, leukocyte, platelet counts), and coagulation indices (fibrinogen, activated partial thromboplastin time, prothrombin time, international normalized ratio, and D-dimer) were compared between patients with and without thrombosis. Thrombotic event type, timing, antithrombotic management, bleeding complications, and mortality (including early mortality within 30 days) were recorded.ResultsEleven of 75 patients (14.7%) developed thrombosis. Baseline demographic characteristics, hemoglobin level, leukocyte count, platelet count, fibrinogen, and activated partial thromboplastin time were comparable between patients with and without thrombosis, whereas prothrombin time, international normalized ratio, and D-dimer levels were numerically higher in patients who developed thrombosis. Most thrombotic events (73%) occurred during active therapy, and the majority were venous (55%). Pulmonary embolism accounted for 36% of all thrombotic episodes, and catheter-associated thromboses represented a clinically relevant subset. Anticoagulation was initiated in 45% of patients with thrombosis and antiplatelet therapy in 18%. Bleeding episodes occurred in 36% of patients who experienced thrombosis. Thrombosis was associated with a 27% all-cause mortality.ConclusionsIn this GCC APL cohort, thrombosis, though less frequent than bleeding, emerged as a serious and clinically significant manifestation associated with substantial morbidity and mortality. These findings underscore the need for vigilant thrombo-hemorrhagic assessment and individualized antithrombotic strategies, particularly during induction and early consolidation therapy.