Quantitative coronary angiography: measurement of the "critical" stenosis in patients with unstable angina and single-vessel disease without collaterals.

Abstract

Quantitative angiographic assessment of proximal coronary artery stenosis was performed in 15 patients with consecutive presentations in two categories defined by clinical and angiographic criteria. Group 1 consisted of 10 patients who had new onset of refractory rest angina and ischemic ST-T changes, but no infarction, single-vessel coronary disease without collateralization, and normal left ventricular (LV) angiograms. Group 2 consisted of five patients who were similar to patients in group 1, but had subendocardial infarction (SEI). Quantitative coronary arteriography, using paired perpendicular angiographic views and digital computation, yielded statistically different lesion dimensions and hemodynamic predictions for the two groups. Minimum stenosis diameters were 0.88 +/- 0.14 (SD) and 0.64 +/- 0.08 mm, respectively, for groups 1 and 2. This corresponded to 72% and 78% diameter reduction and 92% and 95% cross-sectional area reduction for the two groups. These small dimensional differences among lesions in the two groups resulted in large differences in their hemodynamic impact as predicted from classic fluid mechanics theory. We conclude that there are characteristic lesion dimensions for the isolated "critical" stenosis in these selected patients with rest angina. Further small increases in lesions severity result in SEI. Certain practical applications and limitations of these observations are discussed.

Dilation of normal and constriction of atherosclerotic coronary arteries caused by the cold pressor test.

“…14 Statistical analysis. Reactions of epicardial coronary arteries to cold pressor stimulation Group I: controls.…”

Arteriographic assessment of coronary atherosclerosis. Review of current methods, their limitations, and clinical applications.

“…McMahon et al 10 and Rafflenbeul et al2°.<i have measured arterial stenoses in patients with unstable angina. In an attempt to define the "critical" human coronary stenosis producing ischemia at rest, 10 patients were selected for refractory unstable angina, single vessel coronary disease, and the absence of collaterals; a companion group of five patients had a similar picture but also a documented subendocardial myocardial infarction.…”

“…In an attempt to define the "critical" human coronary stenosis producing ischemia at rest, 10 patients were selected for refractory unstable angina, single vessel coronary disease, and the absence of collaterals; a companion group of five patients had a similar picture but also a documented subendocardial myocardial infarction. 10 A third group (McMahon, MM, unpublished observations) of 30 consecutive patients were selected for electrocardiographic and ventricular contraction patterns diagnostic of transmural infarction; 11 of these had severe stenosis proximal to the infarcted zone, and the remaining 19 arteries were completely occluded. The averaged measurements of lesion severity for each of these three clinical groups are given in figure 6.…”

Assessment of Myocardial Perfusion with Single Photon Emission Tomography

“…This range of stenosis is particularly important as stenosis of 50% (75% cross sectional area) is barely hemodynamically significant at peak coronary flow whereas stenosis of 70% (90% cross sectional area) is quite severe at the same peak of coronary flow. 19,20 Tc-MIBI also scored lower false negatives and lower false positives than T1-201, indicating that interpretation of Tc-MIBI images may be more reliable because the better resolution yielded less equivocal images (Figure 3). This inference is true as well in group 2 where Tc-MIBI again scored better with lower false results than with T1-201.…”