[Coronary vasomotor activity in man. Description of a method of quantification and normal values].

The role of vasomotor tone is important in coronary pathology but it has not yet been quantified. The aim of this study was to evaluate the normal maximal variation of diameter between vasoconstriction and vasodilation or the coronary vasomotor capacity: greater diameter-smallest diameter/smallest diameter %. This was performed by two successive pharmacological tests, ergometrine and isosorbide dinitrate (ISDN), the doses of which and modes of administration were defined in a group of 70 patients: Contrast medium: no variations were observed after 5 opacifications at a least 2 minute intervals in 6 patients. Ergometrine test: a single 0.4 mg dose (6 patients) gave a maximal response equal to that obtained with progressive increments 0.1, 0.2, 0.3, 0.4 mg (9 patients). Two opacifications at 3 and 5 minutes were adequate to assess the vasoconstriction with an underestimation of less than 3% compared with a 10 minute control. ISDN test: 3 mg was the maximal haemodynamically well tolerated dose in the majority of patients. This dose gave the same response whether administered by intracoronary (18 patients) or intravenous injection (10 patients). Maximal vasodilatation was obtained after 2 to 4 minutes. A single coronary opacification 2 minutes after injection of ISDN underestimated the vasomotor capacity by 9.3% compared to that calculated after 5 opacifications performed over a 10 minute period. We propose the following protocol: intravenous injection of 0.4 mg of ergometrine with 2 opacifications of the coronary arteries after 3 and 5 minutes respectively. This followed by intravenous or intracoronary injection of 3 mg of ISDN followed by opacification 2 minutes later.(ABSTRACT TRUNCATED AT 250 WORDS)