Classical Blalock-Taussig shunting is rarely performed today, thus contemporary data on the arm blood flow after this procedure are lacking. The aim of the study was to evaluate the peculiarities of the arterial blood supply to the arm in a patient with the classical Blalock-Taussig shunt 14 years after the procedure. The article describes a case of a male patient with a congenital heart disease – double outlet right ventricle, malposition of the great arteries, pulmonary stenosis and subaortic ventricular septal defect, who underwent a classical right Blalock-Taussig shunting at the age of 9 months. Rastelli correction with a pulmonary homograft insertion was performed at the age of 4 years. The pulmonary homograft was replaced in 2017, when the client was 15 years old. The patient presented with no complaints in 2017, his arms were symmetrically developed. Digital wrist and distal forearm X-ray examination revealed identical ossification of both arms. Dopplerography confirmed a normal three-phase blood flow in the left brachial artery and evaluated a monophasic blood flow in the right brachial artery. The normal arterial signal showed a systolic antegrade peak with a small retrograde wave and a residual antegrade blood flow. The collateral pattern consisted of a slow systolic component of reduced amplitude and prolonged acceleration time, followed by an uninterrupted diastolic antegrade blood flow. Ultrasonography evaluated the diameters of the brachial arteries (D) and the velocity time integral (VTI) of the total antegrade blood flow in both arteries. A right to left blood brachial flow ratio Qr/Ql was calculated according to the formula Q . D The right to left arterial blood flow ratio was 1, which suggested an efficient collateralization in the right arm. Invasive blood pressure measurement in the radial arteries showed 116/67 mmHg on the left and 87/64 mmHg on the right side. The waveform of the left radial artery depicted a fast upslope, a sharp peak, followed by a fast downslope with a dicrotic notch. The right arm gave a slow ascending curve, followed by a plateau and a descending component with a less prominent dicrotic notch. Pulse oximetry showed identically high saturation in both arms, but the plethysmography waveform was flattened in the right arm as compared to the normal pattern on the left side. Transection of the subclavian artery distally to the origin of the thyrocervical trunk during the classical Blalock-Taussig shunt enables sufficient blood supply to the arm through the scapular collateral network feeding the axillary artery. The collaterals dilate and the lack of systolic component is compensated by the prolonged antegrade blood flow during the diastole. Both the Doppler resistance index and the diastolic blood flow were comparable on both sides indicating similar tone of the arterial basins. In conclusion, the investigation detected a reduced systolic component of the blood waveform on the side of the classical Blalock-Taussig shunt, which corresponds to the delay of the cardiac output while passing through the collaterals, compensated by a markedly prolonged diastolic portion. The clinical effectiveness of the collateralization was high in the long term after the subclavian artery transection in its distal part.
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