Antiplatelet Agents in Microvascular Surgery

Abstract

Despite advances in instruments, suture materials, and techniques, thrombosis at the anastomotic site is still a problem in microvascular anastomosis. Various pharmacologic agents have been used to inhibit or suppress the process of thrombosis, and the results have been variable.In the present study, a scanning electron microscopic was used to evaluate the roles of aspirin, dipyridamole, and prostaglandin D2 (PGD2) to assess their effects in microvascular anastomosis. Materials and MethodsThirty-five New Zealand rabbits weighing between 2 and 4 kg were selected and divided into a control group and three experimental groups. The animals were anesthetized with intramuscular ketamine hydrochloride (30 mg/kg) and intravenous pentobarbital (20 mg/kg). Supplemental doses were added to maintain a good level of surgical anesthesia.The groins of the animals were shaved and painted with povidone iodine and draped sterile. A 4-cm-long incision was made in the femoral region to expose the femoral vessels. Proximal and distal microclips were applied and a longitudinal arteriotomy was then made in the femoral artery. The arteriotomy incision was closed using 10 &dquo;0&dquo; BV-6 monofilament nylon (Ethicon, Inc., Sommerville, NJ). A Zeiss operating microscope and standard microinstruments were used.Following closure of the arteriotomy, blood was permitted to flow for 15 minutes. The microclips were then applied 5 mm below and above the arteriotomy site, and the segment of the artery between the clips was excised under the microscope (25x), opened longitudinally, and gently washed with normal saline solution. The flattened artery was fixed with a buffered 2% glutaraldehyde (pH 7.2) solution for 5 minutes, then stored in the same solution for 24 hours. The specimen was dehydrated by serial passage through 30%, 50%, 75%, and 95% ethanol.

Scanning electron microscopy of crush/avulsion arterial trauma: Effect of heparin and aspirin administration

“…Other groups have looked closely at the thrombus composition after various modes of arterial i n j~r y .~~?~* Such findings are similar to the present study, with a mix of fibrin and activated platelets seen in the thrombus27 and predominantly fibrin after aspirin administration. 28 A shortcoming of this C/A model is the high success achieved with a single bolus of heparin. First, the high percentage of patency makes comparisons to other highly successful therapeutic agents and combinations (heparin/ aspirin) difficult.…”

Die Anwendung von Prostaglandin E 1 bei mikrovaskulären Rekonstruktionen der oberen Extremität nach Akuttraumen

“…Voraussetzung hierfür ist eine spannungsfreie Anastomose, die durch sparsame Kürzung des zentralen und peripheren Gefäßstumpfes erreicht wird. Entscheidend verantwortlich ist der Zustand der Gefäßwand zum Zeitpunkt des Eingriffs [8,17,36] und die freie Gefäß-durchgängigkeit postoperativ [23].…”

“…Dieses soll der Prophylaxe von thrombotischen Gefäßverschlüssen dienen [31,33].Von den Antikoagulantien wird das Heparin [14,15,25,26,31,33] am häufigsten eingesetzt, von den Fibrinolytika findet die Urokinase vielfach Verwendung [12,14,15,25,26,31].Aus der Gruppe der vasoaktiven Medikamente wird das Prostaglandin E 1 (Prostavasin®) bei Replantationen bevorzugt im asiatischen Raum erfolgreich eingesetzt. Zur Hemmung der Thrombozytenaggregation hat im klinischen Alltag vor allem die Acetylsalicylsäure einen hohen Stellenwert [23,29,30,33]. Eine vasodilatierende Wirkung auf die Gefäßwand wird damit aber nicht erzielt.…”

Improved Microsurgical Anastomotic Patency with Low Molecular Weight Heparin

“…2 Some complications may result from thrombotic occlusion at the anastomosis, while others may result from alterations of the microcirculation despite patent anastomoses. Many systemic therapeutic agents have been evaluated as possible means for improving results, includ-ing those that primarily affect platelet aggregation, such as aspirin, 3 dipyridamole, 4 dextran, 5 and prostacyclin analogs, 6 and those that primarily affect the fibrin clot, such as heparin 78 and streptokinase. 910 Low molecular weight heparin (LMWH) has been found to be as effective as unfractionated heparin (UFH) in the preservation of patency of traumatic veins.…”