The response of canine veins to three types of abdominal surgery: a scanning and transmission electron microscopic study.

Several studies have suggested that events which initiate deep venous thrombosis (DVT) occur in the early postoperative or interoperative period. Since DVT is a complication of many surgical procedures, an understanding of the early events which initiate DVT would be highly desirable. We have studied these events in a canine surgical model. The early response of the endothelium and the adhesion of blood elements to the luminal surface of veins was compared following three types of surgical trauma. Sixteen dogs were divided into four groups (control, splenectomy, hysterectomy, intestinal anastomoses) of four animals each. Blood was removed by perfusion 4 hours after anesthesia alone (control dogs) or anesthesia and surgery (experimental dogs). Jugular veins were removed for scanning and transmission electron microscopy. Veins from control dogs were covered by a continuous sheet of endothelial cells with some pseudopod formation and minor deposition and adhesion of cellular and noncellular material on the luminal surface. The response of veins from experimental animals varied considerably in the three types of surgery studied. The least-affected veins were those from splenectomized animals. These veins had patchy areas of cellular and noncellular material (10 veins) and occasional microthrombi deposited on the luminal surface (one vein). The veins from dogs subjected to hysterectomy exhibited greater endothelial alteration, including crater formation (two veins) and more cellular adhesion, particularly erythrocytes (eight veins). The veins from intestinal anastomoses animals exhibited the greatest response. In these animals there was considerable cellular and noncellular material deposited on the luminal surface of six veins from three of the four animals. The cellular material consisted primarily of erythrocytes and leukocytes, and the noncellular material was an amorphous granular substance. The other two veins were similar in appearance to the control veins. These findings would support the concept that deep venous thrombosis can begin in the interoperative or early postoperative period and that therapeutic intervention in the preoperative and interoperative periods might help prevent subsequent DVT.