Prognostic value of modified thrombelastometry for thromboembolic risk stratification in neurosurgical patients: protocol for a prospective, multicenter, observational study (TENS)

Background and Objectives Neurosurgical patients, particularly those with intracranial tumours such as glioma or meningioma, face a markedly elevated risk of venous thromboembolism (VTE), with reported rates of deep vein thrombosis between 15% and 70% depending on tumour entity and surgical extent. Current prophylactic strategies rely predominantly on pharmacological and mechanical measures and do not account for the individual complexity of coagulation dynamics. Modified thromboelastometry, employing a low-dose tissue plasminogen activator (TPA) test, enables functional assessment of both fibrinolytic capacity and prothrombotic states at the point of care. We hypothesize that preoperative and perioperative thromboelastometric parameters — in particular lysis time (LT) in the low-dose TPA test — are associated with the occurrence of thromboembolic events in neurosurgical patients. Methods TENS is a prospective, multicenter, observational prognostic factor study targeting 350 evaluable participants (up to 369 enrolled to account for attrition) across four university hospitals in Cologne, Munich (two centres), and Oldenburg. Eligible patients are adults (≥ 18 years) scheduled for neurosurgical procedures involving intracranial tumour resection or with an anticipated operative duration of ≥ 4 h. Thromboelastometric measurements (EXTEM, INTEM, FIBTEM, low-dose TPA test) are performed at three defined time points: before surgery, at the end of surgery, and on postoperative day 1. The primary objective is to assess the prognostic association between lysis time (LT) in the low-dose TPA test and objectively imaging-confirmed venous thromboembolic events occurring within 30 days after surgery. Secondary endpoints comprise further thromboelastometric parameters, standard coagulation laboratory values, and clinical outcomes including length of hospital stay, duration of surgery, ICU stay, and days at home at day 30. Conclusions Modified thromboelastometry has the potential to improve individualised risk stratification for thromboembolism in neurosurgical patients. If lysis time in the low-dose TPA test demonstrates prognostic value for thromboembolic events, this could inform the development of novel diagnostic and therapeutic algorithms for high-risk surgical populations. Trial registration, Date Deutsches Register Klinischer Studien (DRKS), No. DRKS00034388, registered October 8, 2024. Anonymised participant-level data and the statistical analysis code will be made available upon reasonable request to the corresponding author following publication of the primary results, subject to applicable data protection regulations and the terms of the institutional data sharing agreement (see chapter The full study protocol will be publicly accessible via the German Clinical Trials Register (DRKS, No. DRKS00034388).Trial status: The study is currently in active recruitment. Recruitment was initiated at the coordinating centre in Cologne on 19 December 2024, with additional centres opening after completion of their local approval and site-initiation processes. As of March 2026, fewer than 50% of the target sample of 350 evaluable participants had been enrolled. Recruitment is expected to be completed by March 2027.