Heparin-induced thrombocytopenia with thrombosis: Incidence, analysis of risk factors, and clinical outcomes in 108 consecutive patients treated at a single institution

Abstract

Heparin-induced thrombocytopenia with thrombosis (HITT) can lead to serious morbidity and may be potentially fatal. We reviewed our experience with this entity over a 4-year period, to determine the following: 1) incidence and type of thrombosis in patients with heparin-induced thrombocytopenia (HIT), 2) clinical consequences of thrombosis, i.e., amputation, cerebrovascular accidents and death, 3) risk factors associated with development of thrombosis, and 4) impact of therapy on clinical outcomes in patients with HITT. Between 1991-1994, 108 patients were diagnosed to have HIT by heparin-induced platelet aggregation test. Thirty-two (29%) of these developed thrombotic complications, of which 20 were venous, 8 arterial, and 4 both. Five of the 32 died, 3 underwent amputations, and 3 had cerebrovascular accidents. The patients who developed thrombotic complications, when compared to those with HIT alone, were older (68.7 ± 11.5 vs. 63.3 ± 16 years, P = .05), had more severe thrombocytopenia (platelet count 46,300 ± 30,400/mm 3 vs. 62,500 ± 34,400/mm 3 , P = .02), and developed it earlier (6.0 ± 2.9 vs. 7.4 ± 3.1 days, P = .03). Multivariate analysis showed that severity of thrombocytopenia and early fall in platelet count were independent risk factors for development of thrombotic complications. We did not find an association between development of thrombosis and clinical events (myocardial infarction, cardiac procedures or surgery, noncardiac surgery, and sepsis) that occurred immediately prior to onset of thrombocytopenia. Heparin was stopped in all 32 patients with HITT. Six received no additional therapy, and one received a single dose of aspirin. Three of these 7 died. The other 25 received anticoagulant or multiagent therapy, with 2 deaths. The death rate was lower in those who were treated with anticoagulant or multiagent therapy (P = .05). We conclude that: 1) Thrombotic complications occur in about 29% of hospitalized patients who develop HIT. 2) Early, severe fall in platelet count in elderly patients receiving heparin appears to be associated with development of thrombotic complications. 3) Our data do not show an association between development of thrombotic complications and clinical events immediately preceding the diagnosis of HIT. 4) In addition to discontinuation of heparin, anticoagulant or thrombolytic therapy should be considered in patients with HITT. Am.

Heparin-PF4 Antibodies in Heparin Induced Thrombocytopenia: Its Relationship with FcgRIIa Polymorphism

“…Fifty percent of HIT patients may be asymptomatic, 10% may have bleeding manifestation due to thrombocytopenia, 10% may have skin necrosis and approximately 30% of HIT patients may have thrombotic commlications due to platelet activation [5][6][7] . If the patients of HIT have thrombosis, heparin needs to be stopped and replaced by thrombin inhibitors.…”

Heparin-Induced Thrombocytopenia-Associated Thrombosis in Pediatric Intensive Care Patients

“…2,8,9 About 29% to 88% of adults with HIT develop arterial or venous thrombosis, with venous thrombosis being the more common complication. 1,4,9,10 HIT-induced thrombosis is associated with a high risk of mortality. 9,10 Although HIT occurs mainly in patients given therapeutic doses of heparin or systemic prophylaxis, it has also been reported in adults who were only exposed to heparin for "flushes" to maintain patency of intravenous lines, 11 and in patients previously sensitized with heparin-coated catheters only.…”

“…1,4,9,10 HIT-induced thrombosis is associated with a high risk of mortality. 9,10 Although HIT occurs mainly in patients given therapeutic doses of heparin or systemic prophylaxis, it has also been reported in adults who were only exposed to heparin for "flushes" to maintain patency of intravenous lines, 11 and in patients previously sensitized with heparin-coated catheters only. 12 Although there are sufficient data regarding HIT and its thromboembolic complications in adults, little is known about the incidence of HIT in children.…”

Heparin‐induced thrombocytopenia presenting with thrombosis of multiple saphenous vein grafts and myocardial infarction

“…The three most frequent sites of arterial thrombosis in order are limbs, cerebrovascular, and coronary arteries. Less commonly observed events include acute mesenteric artery thrombosis, producing bowel ischemia, renal artery thrombosis, and distal aortic artery thrombosis leading to spinal cord infarction [7][8][9].…”