Emergency transcatheter balloon recanalization of acutely thrombosed modified Blalock-Taussig shunts

Modified Blalock-Taussig shunts are used to palliate a variety of cyanotic heart diseases associated with reduced pulmonary blood flow. Acute shunt thrombosis in patients with shunt-dependent pulmonary blood flow can result in life-threatening hypoxia. We describe our experience of emergency transcatheter recanalization in 5 severely hypoxic children with acute shunt occlusion.

Five patients with ages ranging between 5 and 24 months (median 11 months) and weight ranging from 4 to 8 kg (median 5 kg) presented with severe hypoxia, acidosis and hypotension following acute occlusion of modified Blalock-Taussig shunts placed 11 days to 12 months ago. As severe hypoxia (saturation range 3 5%-5 0%), acidosis and a state of shock in all the patients increased the risk for a redo surgical procedure, they were taken up for emergency transcatheter recanalization within 2-6 hours of hospitalization. This was done by positioning a Judkin's right coronary catheter at the mouth of the thrombosed shunt, crossing the shunt with a guidewire and serial dilatations with coronary and/or peripheral angioplasty balloons to the size of the graft. This technique was immediately successful in 4 of the 5 patients, thereby avoiding a repeat palliative operation. In 2 patients with residual stenosis, stents were used to restore luminal patency. One patient with acute stent thrombosis was managed successfully with local delivery of thrombolysis for 36 hours, which resulted in good luminal patency. At follow-up after 6 and 12 months, the shunts in both the stented patients are patent, with an oxygen saturation of 78% and 80%, respectively. In 2 other patients who had undergone plain balloon angioplasty, the shunts remained patent for 11 days (died of bronchopneumonia and septicemia) and 3 months, respectively. The procedure was unsuccessful in one very sick patient in whom the shunt had a tortuous course.

Transcatheter recanalization of an acutely thrombosed Blalock-Taussig shunt is feasible. It can offer satisfactory short-term palliation in selected patients. Stents may play a role in patients with residual narrowing after dilatation. The procedure can be expeditiously accomplished in an emergency situation in a severely hypoxic child and may be a realistic alternative to surgery or thrombolysis.