We tested the hypothesis that transcutaneous electrical nerve stimulation (TENS) over the stellate ganglion region would reduce sympathetic overstimulation and improve femoral blood flow (FBF) after coronary artery bypass graft surgery. Thirty-eight patients (20 men, 24 New York Heart Association class III to IV) were randomized to 5-day postoperative TENS (n = 20; 4 times/day; 30 min/session) or sham TENS (n = 18) applied to the posterior cervical region (C7 to T4). Sympathetic nervous system was stimulated by the cold pressor test, with FBF being measured by ultrasound Doppler. Femoral vascular conductance (FVC) was calculated as FBF/mean arterial pressure (MAP). Six-min walking distance established patients' functional capacity. Before and after the intervention periods, pain scores, opiate requirements, and circulating beta-endorphin levels were determined. As expected, preoperative MAP increased and FBF and FVC decreased during the cold pressor test. Sham TENS had no significant effect on these variables (p > 0.05). In contrast, MAP decreased in the TENS group (125 +/- 12 versus 112 +/- 10 mmHg). This finding, in association with a consistent increase in FBF (95 +/- 5 versus 145 +/- 14 ml/min), led to significant improvements in FVC (p < 0.01). Moreover, 6-min walking distance improved only with TENS (postsurgery-presurgery 35 +/- 12 versus 6 +/- 10 m; p < 0.01). TENS was associated with lesser postoperative pain and opiate requirements but greater circulating beta-endorphin levels (p < 0.05). In conclusion, stellate ganglion TENS after coronary artery bypass graft surgery positively impacted on limb blood flow during a sympathetic stimulation maneuver, a beneficial effect associated with improved clinical and functional outcomes.

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