Masayoshi Sugihara

Preservation of endothelium-dependent vasodilation in the spastic segment of the human epicardial coronary artery by substance P

The objective of this study was to determine if endothelium-dependent vasodilation is preserved in the spastic segment of the epicardial coronary artery. Segmental responses of the coronary artery to substance P were examined by the use of a quantitative angiographic technique in 21 patients with variant angina. Coronary diameter at the basal state did not differ between the spastic and the nonspastic segments (2.3 +/- 0.2 mm, 2.3 +/- 0.4 mm, p greater than 0.05). Changes in coronary diameter in response to substance P did not differ between segments with ergonovine-induced spasm and nonspastic segments. Maximal dilation averaged 27.1 +/- 9.5% in the spastic segment and 24.4 +/- 9.6% in the nonspastic segment (expressed as a percent increase over the value before drug administration). It appears that both the potential of the endothelium to release endothelium-dependent relaxing factor and the dilating response of the smooth muscle to endothelium-dependent relaxing factor are preserved, even in the spastic segment.

Effects of continuous intravenous infusion of isosorbide dinitrate on development of tolerance to vasodilating action in human epicardial coronary arteries

This study was performed to determine the effects of long-term intravenous infusion on the coronary vasodilating actions of continuous intravenous and bolus intracoronary administration of isosorbide dinitrate (ISDN). With quantitative coronary angiography, the coronary diameter and the vasodilating response to intracoronary ISDN (1 mg) at angiographically normal segments were studied before and after intravenous administration of ISDN, 10 to 60 micrograms/min for 1 hour, 2 days, or 5 days. The vasodilating effects of intravenous ISDN were 72% +/- 13%, 65% +/- 21%, and 6% +/- 11% of the response to intracoronary ISDN in the baseline study in each group. Irrespective of the duration of intravenous infusion, subsequent intracoronary ISDN dilated coronary arteries to extent similar to that observed in each baseline study. In conclusion, significant coronary vasodilating effects of intravenous ISDN were observed after a 2-day infusion, whereas tolerance to the vasodilating effects apparently developed within 5 days of infusion. The vasodilating response to bolus intracoronary ISDN was preserved even when the vasodilating effects of intravenous ISDN were no longer present.

Isolated coronary ostial stenosis in Takayasu's arteritis: case report and review of the literature.

This report describes a rare clinical course of a young Japanese woman with Takayasus arteritis and a review of the literature. Her first symptom was angina pectoris due to isolated left coronary ostial stenosis, which was relieved by aortocoronary bypass grafting surgery using a saphenous vein graft. At that time, the C-reactive protein was negative and the histopathologic findings of the specimens of the aorta could not confirm aortitis. Although she was free from any cardiovascular symptoms for about fifteen years,. syncopal attacks occurred owing to severe stenosis of the major branches of the aortic arch revealed by intravenous digital subtraction arteriograms. Thus, Takayasus arteritis could be a cause of coronary ostial stenosis in young women even if the inflammatory findings are negative and the major branches of the aortic arch are not involved at operation. In addition, revascularization using internal thoracic arteries might possess a potential risk of coronary insufficiency due to a later involvement of these proximal arteries.