The Effect of Nitroglycerin on Arterial Stiffness of the Aorta and the Femoral-Tibial Arteries -Monitoring with a Stiffness Parameter β- Derived Vascular Index-

Aim: The effect of nitroglycerin on proper arterial stiffness of the arterial tree has not been fully clarified. The cardio-ankle vascular index (CAVI), which is an application of the stiffness parameter beta theory on the arterial tree from the origin of the aorta to the ankle, was developed recently. Furthermore, the stiffness of the aorta (heart-thigh beta (htBeta)) and of the femoral-tibial arteries (thigh to ankle beta (taBeta)) could be monitored by applying the same theory. The effects of nitroglycerin on CAVI, htBeta, and taBeta were studied comparing the values of healthy people and those of arteriosclerotic patients. Methods: The subjects were healthy people (CAVI <7.5, n=25) and arteriosclerotic patients (CAVI >9, n=25). Nitroglycerin (0.3 mg) was administrated sublingually, and various arterial stiffness indices were measured at one-minute intervals for a period of 20 minutes using Vasera VS-1500 (Fukuda Denshi, Tokyo). Results: After the administration of nitroglycerin in healthy people, CAVI decreased significantly after 5 min. [from 6.76(6.32-7.27) to 5.50(4.70-6.21), P<0.05], and recovered after 15 min. htBeta [from 5.10(4.76-5.76) to 3.96(3.35-4.79), P<0.05], and taBeta [from 14.41(10.80-16.33) to 10.72 (9.19-13.01), P<0.05] also decreased significantly. In arteriosclerotic patients, CAVI decreased after 5 min. [from 10.47(9.67-11.29) to 9.71(8.74-10.57), P<0.05] and recovered after 15 min. htBeta did not significantly change [from 12.00(11.46-13.21) to 11.81(10.14-13.83), ns], but taBeta decreased significantly [from 18.55(12.93-23.42) to 12.37(9.68-16.99), P<0.05]. Conclusion: These results indicate that a nitroglycerin-induced decrease of arterial stiffness is more prominent in muscular arteries than in elastic arteries, and this effect was preserved much more prominently in arteriosclerotic patients than in healthy people.