August 1, 1981Circulation169 citations
View Full PaperMagnitude of dilatation of large and small coronary arteries of nitroglycerin.
Key Result
Sublingual nitroglycerin induced coronary artery dilatation, with the greatest magnitude of vasodilatation observed in arteries with the smallest control diameter.
Key Points
- The study aims to determine vasodilatory responses of large and small coronary arteries to nitroglycerin.
- 34 patients were assessed using quantitative magnification coronary angiography.
- Nitroglycerin (0.4 mg, sublingual) was administered prior to measurements.
- Both large epicardial and small intramyocardial coronary arteries were evaluated for dilatation.
- CAs with the smallest control diameter showed the greatest magnitude of vasodilation.
- Coronary stenoses exhibited less dilation than nonstenosed segments of similar diameter.
- No significant difference in response when excluding stenotic areas, regardless of coronary artery disease presence.
Structured PICO
Does sublingual nitroglycerin improve vasodilatation differently based on the baseline size and location of coronary arteries?
P
Population
34 patients evaluated for coronary artery vasodilatory responses before and after sublingual nitroglycerin.
I
Intervention
Nitroglycerin 0.4 mg sublingual.
C
Comparator
Baseline measurements (before nitroglycerin administration).
O
Outcome
Vasodilatory responses (magnitude of dilatation) of segments of large epicardial left coronary artery, small intramyocardial coronary arteries (0.3-1.0 mm), coronary stenoses, and coronary arteries filled by collaterals, measured by quantitative magnification coronary angiography.surrogate
The principal determinant of coronary artery vasodilatory response to sublingual nitroglycerin is the baseline size of the artery, with smaller vessels exhibiting greater dilatation.
Abstract
Vasodilatory responses of segments of large epicardial left coronary artery (CA), small intramyocardial CAs (0.3-1.0 mm), coronary stenoses and CAs filled by collaterals were determined in 34 patients. Measurements were made before and after nitroglycerin (0.4 mg, sublingual) by means of quantitative magnification coronary angiography using photospot film and a calibrated 6-power viewing device. The left main CA, proximal, middle and distal anterior descending and circumflex segments, and small CAs showed dilatation that varied in magnitude. When magnitude of dilatation was compared with control diameter of the vessel and its location, control diameter proved to be the significant independent variable. CAs with the smallest control diameter showed the greatest magnitude of vasodilatation. CA branches filled by collaterals had vasodilatation similar in magnitude to that of CAs of comparable control diameter. Although coronary stenoses dilated, the magnitude of dilatation was less than that observed in nonstenosed arterial segments of similar control diameter. When areas of stenosis were excluded, however, results were similar regardless of whether the patient had CA disease. These data indicate that a principal determinant of the CA vasodilatory response to nitroglycerin is the size of the artery before nitroglycerin.