Handgrip strength after the Blalock-Taussig shunt: 14 to 34 year follow-up

To determine the long-term functional impact of the Blalock-Taussig (BT) shunt, we studied handgrip strength in 56 patients (10-28 years) following total repair of tetralogy of Fallot. Of the 56, 16 (29%) had a previous right BT shunt, 5 of 56 (9%) had a previous left BT shunt, and the remaining 35 patients either had a Potts shunt or primary total repair. The mean age at the time of right BT was 2.8 +/- 1.6 (SD) years, left BT 1.7 +/- 1.2 years, and total repair for all patients was 7.1 +/- 2.2 years. Mean age at the time of study was 26 +/- 9 years. Right-and left-handgrip strength were measured with a Jamar dynamometer, averaging the results of grip position 2, 3, and 4 to accommodate variation in hand size. Since absolute values of hand strength were strongly associated with sex (p = 0.006) and body surface area (p = 0.016), we calculated the ratio of right-hand to left-handgrip strength (RL ratio). The RL ratios were: 0.98 +/- 0.13 (right BT), 1.21 +/- 0.11 (left BT), and 1.13 +/- 0.16 (no BT): (p = 0.004 right BT vs. no BT, p = 0.07 left BT vs. no BT, Wilcoxon rank sum test). Thus, although frequently clinically inapparent, handgrip strength tested many years post-BT shunt is reduced on the side of the shunt.