Elimination of variable vasomotor tone in studies with repeated quantitative coronary angiography

Abstract

In quantitative coronary angiographic studies, unintentional changes of coronary vasomotor tone may have a significant influence on the coronary artery diameters, thereby increasing the variability in the measurements. To obtain objective data on these measurement variabilities, two protocols were designed to assess the influences of ionic and nonionic radiographic contrast media on the mean diameters of angiographically normal coronary arteries. The vessel sizes were determined with the CAAS using automated edge detection techniques. In 21 patients (study no. I), coronary angiograms were taken in identical angiographic projections before (control), and immediately following several (at average 7) subsequent diagnostic dye injections administered over a period of about 7 min. The ionic contrast agent diatrizoate 76% induced a coronary dilation of 19 +/- 7% (mean +/- s.d., p less than 0.001; n = 10); the nonionic agent iopromide 370 increased the coronary artery diameters by only 6 +/- 4% (p less than 0.01; n = 11). In another 11 patients (study no. II) coronary angiograms were obtained using the nonionic contrast medium iopamidol 300 at 5, 8, 10 and 11 min after the control acquisition; this protocol was repeated in the same patients with diatrizoate 76%. With iopamidol, coronary diameter changes were not significant at any time; with diatrizoate, however, coronary dilation was measured at 10 min (2 +/- 2%; p less than 0.01) and at 11 min (10 +/- 3%; p less than 0.001). In a third study it was tested, whether standardization of coronary vasomotor tone (e.g. in coronary angiographic follow-up studies) is possible by the induction of a reproducible maximum coronary dilation with nitrocompounds. In 12 patients, the mean diameters of angiographically normal coronary segments were analyzed before and at various times after i.v. administration (over 4 min) of 0.025 mg SIN-1/kg bodyweight. Coronary dilation was maximal at 10 or 15 min after the onset of the SIN-1-infusion (29 +/- 5%; p less than 0.001). 0.8 mg nitroglycerin given s.l. at 15 min did not further dilate the coronary arteries (28 +/- 7%). One hour after SIN-1, coronary dilation still amounted to an average of 24 +/- 8% (p less than 0.001) and became 'maximal' again, when 0.8 mg nitroglycerin was again administered sublingually (28 +/- 8%; p less than 0.001). In conclusion, short-term variability of coronary vasomotor tone induced by ionic radiographic contrast media can be eliminated by the use of nonionic contrast agents and observation of injection intervals of at least 2 min. In quantitative coronary angiographic follow-up studies, as well as during acute interventions (e.g., PTCA), identical baseline vasomotor tone can be achieved by induction of the maximal coronary dilation using nitrocompounds.

Nitrate‐induced coronary vasodilation by stress‐magnetic resonance imaging: A novel noninvasive test of coronary vasomotion

“…Third, our study population was composed of healthy volunteers, which may be very different from study populations recruited in diagnostic angiographic studies. In addition, it should be considered that the radiographic contrast medium itself can cause coronary vasodilation, especially when it is used in short intervals (17), and that the catheters, especially intravascular ultrasound catheters, can stimulate the endothelium, resulting in vasoconstriction (6). MRA is free of ionizing radiation and contrast agents, it does not perturb vasomotor tone with catheters, and it has a good temporal resolution.…”

A clinical strategy to improve the diagnostic performance of 3T non-contrast coronary MRA and noninvasively evaluate coronary distensibility: combination of diastole and systole imaging

“…Although the CAG was carried out in the suspected CAD patient, this examination is more suitable for measuring the lumen diameter and could not measure the lumen area directly. In addition, the contrast medium applied in CAG can cause coronary vasodilation [37] and the catheters used in intravascular ultrasound imaging can stimulate the endothelium [38], resulting in vasoconstriction. These factors may affect accurate assessment of CDI.…”

Clinical Application of Non‐Contrast‐Enhanced Dixon Water‐Fat Separation Compressed SENSE Whole‐Heart Coronary MR Angiography at 3.0 T With and Without Nitroglycerin

“…However, both methods have limited clinical application due to their invasiveness. In addition, the contrast medium applied in CAG can cause coronary vasodilation 36 and the catheters used in intravascular US 37 can stimulate the endothelium, resulting in vasoconstriction. These factors may affect accurate assessment of coronary vasodilation.…”