Response of large superficial dorsal hand veins to locally infused nitroglycerine in young, normal subjects

Abstract

Nitroglycerine relaxes vascular smooth muscle and is routinely use to treat angina and congestive heart failure. However, in preliminary observations of severe heart failure patients, nitroglycerine did not dilate superficial veins, although the observations were made at the top of the distention-pressure relationship for superficial veins. Hence, the purpose of this study was to examine whether the venodilating effects of nitroglycerine could be demonstrated at lower distending pressures. Dorsal hand vein diameter was measured using a linear variable differential transformer in 14 normal, healthy subjects, 20-34 years old. The distention-pressure response was obtained by applying 10-mmHg (1 mmHg = 133.3 Pa) increments of distending pressure from 10 to 50 mmHg. Distention-pressure curves were constructed during randomized, single blind local intravenous infusions (constant rate of 0.1 mL/min) of dextrose or nitroglycerine (100 ng/min). No significant differences were observed during the study in heart rate or arterial pressure between dextrose and nitroglycerine. No difference in superficial dorsal venous distension at any of the five applied distending pressures was observed during infused dextrose compared with infused nitroglycerine (10 mmHg, 0.21 +/- 0.03 vs. 0.23 +/- 0.04 mm; 20 mmHg, 0.63 +/- 0.06 vs. 0.63 +/- 0.05 mm; 30 mmHg, 0.82 +/- 0.08 vs. 0.82 +/- 0.08 mm; 40 mmHg, 0.93 +/- 0.09 vs. 0.94 +/- 0.09 mm; 50 mmHg, 0.98 +/- 0.10 vs. 0.98 +/- 0.09 mm; p = ns). Thus, locally infused nitroglycerine, at very high local concentrations, was unable to significantly vasodilate large superficial dorsal hand veins of normals even at low distending pressures. Further investigation is required of the actions of nitroglycerine on different venous beds and the arterial circulation, in addition to possible difference in response of subject populations such as congestive heart failure in which there may be different basal levels of resting venomotor tone.