We are proud to announce the defense of Max Hoebink. His thesis is titled “Monitoring perioperative anticoagulation in vascular surgery”. His research provides valuable new perspectives on antithrombotic strategies during non-cardiac arterial procedures (NCAP), aiming to optimize patient outcomes and standardize clinical protocols.

Heparin Strategies Survey

Two large-scale surveys, both national and international, revealed significant variation in heparin use among hospitals and vascular surgeons. Many specialists expressed dissatisfaction with current protocols. "Our findings highlight the urgent need for high-quality evidence," says Max Hoebink.

Anti-XA Test Evaluation

In a scoping review Hoebink examined the clinical applicability of the anti-Xa test for monitoring heparinization during NCAP. Hoebink explains, “Anti-Xa testing can play a pivotal role in improving perioperative monitoring, especially as a reference in laboratory settings to validate point-of-care heparin tests and compare heparin administration strategies.”

ACT and Anti-Xa Correlation

Hoebinks research demonstrated a strong correlation and independent association between anti-Xa and ACT measurements during NCAP, using a specific ACT-guided heparinization protocol. Hoebink notes that “this association supports the reliability of our ACT-guided protocol to monitoring heparin therapy during vascular surgery and strengthens the case for more standardized approaches.”

Heparin Dosing Comparison

With a prospective cohort study Hoebink compared outcomes between a single 5000 IU heparin dose and ACT-guided heparinization. Hoebink remarks, “Our results suggest further research is needed to determine the optimal approach for different patient groups.” No significant differences were found in thromboembolic complications, mortality, or bleeding events.

ACTION-1 Trial Preparation

The thesis details the development of the ACTION-1 trial, a randomized study comparing ACT-guided heparinization with a fixed 5000 IU dose during open abdominal aortic aneurysm surgery. A pilot study showed ACT-guided heparinization feasible, and led to improved coagulation times. “The ACTION-1 trial is a crucial step towards evidence-based perioperative anticoagulation,” Hoebink emphasizes.

PhD Defense & ACS Lunch Lecture
The public defense of Max Hoebink will take place on 17 April 2026, 16:00h at the Agnietenkapel. For more information, see the UvA website.

Prior to the defense prof. dr. med. Markus Steinbauer, who is visiting to attend Hoebinks defense, will give a lecture in a special edition of the ACS lunch lecture. For more information, see our event page.