Heparin-Induced Thrombocytopenia and Graft Thrombosis following Endovascular Aneurysm Repair

Heparin-induced Thrombocytopenia in Two Patients Undergoing Abdominal Aortic Aneurysm Surgery

We have experienced 2 cases of heparin-induced thrombocytopenia during unfractionated heparin treatment for disseminated intravascular coagulation after surgery for an abdominal aortic aneurysm. In the first case, as a symptom of disseminated intravascular coagulation gradually improved with antithrombin concentrates and heparin treatment, mesenteric artery thrombosis suddenly occurred, associated with a >50% decrease in platelet count on the 11th day. Although the platelet counts were increasing due to heparin cessation, clinical symptom and coagulation abnormalities worsened to multiple organ failure. In the second case, the platelet count decreased to <10 × 104/µL on the 13th day after the start of unfractionated heparin anticoagulation along with continuous hemodiafiltration, which was indicated for postoperative renal failure. The extracorporeal circuit clotted frequently under an adequate dose of unfractionated heparin. Serologically, heparin—platelet factor 4 complex antibodies were repeatedly detected by enzyme-linked immunosorbent assay. Argatroban, a direct thrombin inhibitor, was introduced as an alternative to unfractionated heparin, and the platelet count improved with a decrease in titers of the antibodies. Disseminated intravascular coagulation is a common complication in cases of abdominal aortic aneurysm and is usually treated in association with unfractionated heparin. It is important to recognize the onset of heparin-induced thrombocytopenia that acute declines in the platelet count and appearance of thrombosis with positive for heparin—platelet factor 4 complex antibodies would suddenly occur in clinical course of disseminated intravascular coagulation.

Heparin-induced thrombocytopenia and endovascular procedures: report of two cases

Heparin-induced thrombocytopenia (HIT) is a transient disorder caused by platelet-activating antibodies against platelet factor 4 (PF4)-heparin complexes. Clinically it translates into arterial or venous thrombosis and carries high morbidity and mortality. The use of large doses of heparin during endovascular repair of abdominal aortic aneurysm could increase the incidence of HIT. We report two cases associating the use of heparin during endovascular repair of abdominal aortic aneurysm with the development of HIT.

Heparin-Induced Thrombocytopenia With Thrombosis After Endovascular Aneurysm Repair

Heparin-induced thrombocytopenia is an immune-mediated syndrome that results from unfractionated heparin or low molecular weight heparin exposure. It often remains unrecognized and undertreated and can cause limb and/or life-threatening thrombosis. The authors present 2 cases of thrombosis: one arterial and the other venous that occurred following endovascular abdominal aortic aneurysm repair. To the authors' knowledge, this is only the second report of arterial thrombosis and the first of deep vein thrombosis as a result of heparin-induced thrombocytopenia developing following endovascular abdominal aortic aneurysm repair. This underscores the importance of considering heparin-induced thrombocytopenia as a potential cause for postendovascular thrombotic complications in the patient who develops thrombocytopenia following this procedure.

Thrombosis of a Bifurcated Endograft Following Lower-Back Microwave Therapy

PURPOSE

To describe an unusual case involving thrombosis in an aortic endograft limb following microwave therapy (MWT) for lumbar pain.

CASE REPORT

A 77-year-old man had successful repair of an abdominal aortic aneurysm with a Vanguard endograft. He had been free of complications during the 3-year follow-up. Five days after the 36-month surveillance angiogram, the patient was treated with MWT for chronic left-sided lumbar pain due to vertebral arthrosis. Immediately after this session, the patient presented with acute ischemia in the left lower limb. Computed tomographic angiography showed a thrombosis of the left limb of the endograft. A femorofemoral crossover bypass was performed. No complication was observed in later surveillance.

CONCLUSIONS

It may be advisable to avoid MWT and other deep heating therapies in patients with endografts. This caution is applicable to other metallic stents.