Bridging after Mechanical Aortic Valve Replacement: 10-Year Experience with Unfractioned Subcutaneous Heparin

Background: Postoperative anticoagulation after mechanical aortic valve replacement is achieved by vitamin K antagonists. For bridging in the early postoperative period, most clinics use intravenous unfractionated heparin. Nevertheless, determining the optimal dosage for individual patients necessitates frequent blood sampling and patients experience immobilization due to the perfusion pump. A fixed regimen of subcutaneously administered unfractionated heparin (sHep) presents an alternative to the established therapeutic options; however, there is currently limited evidence regarding the safety of this approach.

Methods: In this retrospective single-center study, we analyzed 626 patients who underwent primary isolated mechanical aortic valve replacement between 2003 and 2013 in our department. All patients received a fixed regimen of weight-adjusted sHep for bridging (three doses daily; <90 kg bodyweight: 7,500 IU, >90 kg: 10,000 IU). Data on postoperative events related to anticoagulation (stroke, bleeding, valve thrombosis, re-do surgery) were collected and analyzes. Furthermore, patients were classified with regard to surgical urgency. Other end points were the length of stay in the intensive care unit and days until discharge, in-hospital and 30-day mortality rates.

Results: The mean patient age was 68 years. The mean body mass index was 28.6 kg/m². Most patients were presented to us for elective aortic valve replacement (396), followed by 227 urgent and three emergency operations. The average length of stay in the ICU was 3.6 days and 7.5 days in the normal ward.

15 patients needed re-do surgery due to bleeding or hematoma during the hospital stay. No thromboembolic events or valve thrombosis were detected. A total of nine adverse cerebrovascular events were recorded in cranial computed tomography control due to clinical symptoms, including six in elective patients and three in urgent surgery. Seven women and two men were affected. In-hospital mortality stood by eight patients (1.3%) including 6 women (0.95%). The 30-days mortality was 11 patients (1,7%).

Conclusion: In our retrospective analysis, sHep therapy after mechanical aortic valve replacement seems to be a safe alternative to established medical options for bridging. Compared to data from the literature, we did not see increased thromboembolic or bleeding events, or increased mortality. The safe utilization of sHep therapy in the early postoperative phase enhances patient comfort and can alleviate the workload of hospital staff.

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Artikel online veröffentlicht:
13. Februar 2024