Antithrombotic Therapy in Children: Other Cardiac Disorders
Other Cardiac Disorders
Antithrombotic therapy is currently used for several other congenital heart lesions or as a consequence of their surgical treatments.
Blalock-Taussig Shunts: Blalock-Taussig shunts are one form of palliative surgery used to enhance systemic, subclavian artery, to pulmonary artery blood flow in patients with severe or progressive cyanosis, usually secondary to pulmonary stenosis. “Modified” Blalock shunts, where a polytef (Gore-Tex) tube graft is taken from the side of the subclavian artery and anastomosed to the pulmonary, have been used since 1980. Because of its short length and very high flow, acute thrombosis is less common. Since 1980, 647 children with Blalock-Taussig shunts have been studied in 21 level V studies. The incidence of thrombotic occlusion ranged from 1 to 17%. Many investigators used antithrombotic therapy, beginning with therapeutic doses of heparin and followed by low-dose aspirin (1 to 10 mg/kg/d), although others recommended intraoperative heparin with no further anticoagulation. birth control online
Fontan Operation: The Fontan procedure, or a modified version, is the definitive palliative surgical treatment for most congenital univentricular heart lesions. Thromboembolic complications remain a major cause of early and late morbidity and mortality. Reported incidences of venous thrombosis and stroke ranged from 3 to 16% and 3 to 19%, respectively, in the retrospective cohort studies where thrombosis was the primary outcome, and from 1 to 7% in the retrospective cohort studies assessing multiple outcomes. Thromboembolic complications may occur at any time following Fontan procedures, but often present months to years later. No predisposing factors have been identified with certainty, although this may be due to the inadequate power and retrospective nature of the studies. Transoesophageal echocardiography is more sensitive than transthoracic echocardiography for the diagnosis of intracardiac and central venous thrombosis. Despite aggressive therapy, thromboembolic events following Fontan procedures have a high mortality and respond to therapy in <50% of cases. There is no consensus in the literature, or in routine clinical practice, as to the optimal type or duration of anticoagulation. Consequently, a wide variety of prophylactic anticoagulant regimes are in current use. There is an urgent need for large, multicenter prospective trials of prophylactic anticoagulation therapy following Fontan procedures.