Modified Blalock-Taussig-Thomas Shunt

Excerpt

The modified Blalock-Taussig-Thomas shunt (mBTT shunt), previously known as the traditional or classic Blalock-Taussig shunt (BT shunt), is a palliative surgical procedure to treat patients with cyanotic heart diseases characterized by decreased pulmonary artery flow. The first BT shunt was conducted at Johns Hopkins Hospital in 1944 and was the fruit of the collaborative work of three individuals: the pediatric cardiologist Dr. Helen Taussig, the cardiac surgeon Dr. Alfred Blalock, and Mr. Vivien Thomas, a laboratory assistant. Delaval was the first to use the term "Blalock-Taussig shunt" when reporting on a series of patients who underwent this procedure between 1975 and 1979. A request to add the eponym "Thomas" was proposed in 2003 in recognition of the contributions made by Mr. Thomas to the success of this procedure.

The BT shunt aims to supply the pulmonary artery with blood flow sufficient to relieve cyanosis without inducing pulmonary over-circulation. The classic BT shunt procedure was performed through a lateral thoracotomy, dividing the subclavian artery and anastomosing it to the pulmonary artery in an end-to-side manner. The original technique has been modified extensively and has evolved to the mBTT shunt, which utilizes an interposition polytetrafluoroethylene (PTFE) graft to establish a systemic-pulmonary shunt without sacrificing the subclavian artery or any of the brachiocephalic tributaries. In 1976, Gazzaniga et al reported the first use of a PTFE graft to construct an aortopulmonary shunt (see Image. Classic Blalock-Taussig Shunt vs. Modified Blalock-Taussig-Thomas Shunt).

The modified BTT shunt offers many advantages over the original iteration. Using an interposition PTFE graft simplifies the takedown procedure, preserves blood flow to the ipsilateral upper limb, and permits the tighter regulation of shunt flow by tailoring the diameter and length of the graft and choosing the anastomotic site.

This activity reviews the indications, contraindications, required personnel and equipment, surgical technique, and complications of the mBTT shunt procedure and highlights the critical role of the interprofessional team in caring for patients with congenital cardiac anomalies undergoing this procedure.