In-hospital Morbidity and Mortality After Modified Blalock-Taussig-Thomas Shunts

The modified Blalock-Taussig-Thomas shunt is a critically important palliation for patients with insufficient pulmonary blood flow associated with congenital heart disease. After creating a modified Blalock-Taussig-Thomas shunt patients experience high rates of early postoperative morbidity and mortality.

This is a single-institution retrospective cohort study. A query of The Society of Thoracic Surgeons database identified relevant patients whose health records were manually queried for echocardiography and operative reports. Patients with ductal-dependent systemic circulation were excluded. Primary outcomes were early serious adverse events and in-hospital mortality. Secondary outcomes were time to primary outcomes and postoperative lengths of stay. We investigated the correlation of demographics, presence of competitive pulmonary blood flow, and surgical and anatomic factors on outcomes.

After exclusions our cohort comprised 155 patients. Thirty-three patients (21.3%) experienced an early serious adverse event, 10 (6.5%) early shunt malfunction, and 11 (7.1%) in-hospital mortality. Smaller shunt size, smaller shunted pulmonary artery size, surgical approach, and site of proximal shunt anastomosis were independently associated with morbidity and mortality.

Anatomic elements imparting increased resistance along the modified Blalock-Taussig-Thomas shunt predispose to increased morbidity and mortality, particularly in the early postoperative period. Despite the significant heterogeneity of patients receiving such shunts, similar risk profiles are observed regardless of lesion or presence of competitive flow. A surgical approach using thoracotomy with shunt anastomosis to the subclavian artery, where feasible, results in the subclavian artery as the point of natural resistance, allowing for placement of larger shunts and yielding lower morbidity and mortality.