[The effects of isosorbide dinitrate spray on the coronary artery and its modification by the preceding chronic oral therapy with long acting isosorbide dinitrate].

The vasodilatory effect of a new formula of isosorbide dinitrite (ISDN) spray on the left coronary artery was studied by comparing its effects in 46 consecutive patients who subsequently received intracoronary injection with ISDN (2.5 mg). In addition, the influence long acting and ISDN for chronic cases on the vasodilatory effects of ISDN spray and on subsequent intracoronary injection of ISDN was investigated. The patients were divided into two groups, those who had had chronic oral ISDN (Group N; 29 patients) and those who had not (Group O; 17 patients). The vasodilatory effect of ISDN spray was evaluated in segments; 5, 6, 8, 11 and 12 by AHA classification and it dilated those segments by 9.9%, 13.2%, 21.5%, 15.6% and 23.5% respectively. Subsequent intracoronary injection of ISDN dilated those segments by 10.4%, 14.0%, 27.2%, 17.9% and 29.1% respectively. The differences in the degree of vasodilation caused by ISDN spray and that caused by injection in segments 8, 11, 12 were statistically significant. However, the per cent dilation of ISDN spray in segments 5 in group N was 5.9%, and 18.4% in group O, revealing a significant difference depending on previous chronic administration of long acting ISDN. We conclude that ISDN spray did dilate the coronary artery, and subsequent intracoronary administration of ISDN dilated it further in the distal portions of the left coronary artery. Long acting oral ISDN for chronic cases seemed to attenuate the vasodilatory action of ISDN.