Abstract
In 1940 Murray published his paper on the role of “heparin in surgical treatment of blood vessels”. The introduction of heparin as a prophylactic antithrombotic in vascular surgery increased surgical interventions in the arterial circulation. Heparin reduces clotting of blood while clamping arteries and thereby reduces thrombo-embolic complications, local and
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systemic. Heparin is also considered essential during percutaneous endovascular interventions with balloons and stents. Heparin has a major, clinical, disadvantage: the prolonged clotting of blood causes an increase in bleeding complications, such as more blood loss and more blood transfusions. This also increases procedure time, leading to more (infectious) complications. The use of heparin can also lead to the development of heparin induced thrombocytopenia (HIT) syndrome, an unpredictable response of the immune system on the administration of heparin, possibly resulting in arterial and venous thrombo-embolic complications. Another major disadvantage of the use of heparin is the fact that heparin has no linear dose-response curve. This results in an unpredictable therapeutic effect in at least 20% of patients. This underlines the necessity of performing measurements of the actual effect of heparin, also because heparin is used worldwide in all open and endovascular arterial procedures. To develop new, evidence based guidelines for vascular surgery and interventional radiology (IR), a study group was instituted in the Netherlands (CAPPA: Consensus on Arterial PeriProcedural Anticoagulation). This study group performed 2 surveys on anticoagulation amongst Dutch vascular surgeons and IR. Results showed variation on the use of anticoagulation before, during and after arterial open and endovascular procedures. Predominantly heparin was used by most surgeons and IR during procedures as an prophylactic antithrombotic but the applied doses varied importantly. Also for IR, the variety found for the use of heparin in the Netherlands, was not the same as the variety found in the United Kingdom. Systematic reviews of literature on the use of heparin by vascular surgeons during open abdominal aortic aneurysm repair (AAA) and infra-inguinal bypass surgery (IABS) showed not much evidence for the beneficiary effect of heparin. During open AAA repair a trend was observed to harmful side effects such as more blood loss, longer operation time and more blood transfusion when heparin was used. Thrombo-embolic complications were not increased when no heparin was used. In the Netherlands a trial was performed to compare open and endovascular repair op AAA (DREAM trial). A sub-analysis from this trial in the open repair group showed no clinical differences in outcomes when heparin or no heparin was administered. The CAPPA group designed a randomized controlled trial (RCT) on the use of heparin during open AAA repair. Patients will be randomized to a heparin and a no-heparin group. Aim of this NANDA? trial (No Anticoagulation Needed During open AAA repair?), will be to determine if heparin is beneficial as an prophylactic antithrombotic. Multiple other trials on IABS and endovascular interventions are developed. Ultimate goal of these trials will be to create consensus and new guidelines on periprocedural prophylactic antithrombotics in arterial vascular surgery and IR.
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