Temporal variability and correlation with geometric parameters in vasospastic angina: a quantitative angiographic study

Relation of basal coronary tone and vasospastic activity in patients with variant angina

OBJECTIVE

To examine the vasoconstrictor response to ergonovine and the vasodilator response to isosorbide dinitrate in spastic and non-spastic coronary segments from 31 patients undergoing serial angiographic follow up of variant angina.

METHODS

Coronary angiograms and ergonovine provocation tests were repeated at an interval of 45 (SD 15) months apart. While all 31 patients showed a positive response to ergonovine initially, vasospastic responsiveness persisted in only 16 patients at follow up (group 1) and not in the other 15 patients in whom symptoms of variant angina had resolved (group 2). Mean luminal diameter of 170 normal or near normal entire coronary segments (American Heart Association classification) were measured (a) at baseline, (b) after the administration of ergonovine, and (c) after the administration of isosorbide dinitrate, during both the initial and follow up angiograms using a computer based quantitative angiography analysis system (CAAS II).

RESULTS

In vasospastic patients (initial and follow up angiograms in group 1, and initial angiogram in group 2), basal tone was significantly higher in spastic segments compared to adjacent segments or segments in non-spastic vessels. The diagnostic sensitivity and specificity at 20% increase in basal coronary tone for the prediction of vasospasm were 77% and 73%, respectively.

CONCLUSIONS

Coronary artery tone may change in proportion to the activity of variant angina over several years. Contrary to some previous reports, the estimation of basal coronary tone may be useful in the assessment of vasospastic activity in patients with variant angina.

Fluctuation of spastic location in patients with vasospastic angina: a quantitative angiographic study

OBJECTIVES

This study sought to determine whether the location of coronary spastic activity may change over time in patients with persistent variant angina.

BACKGROUND

Although electrocardiographic studies have provided indirect evidence to indicate that the location of ischemia may change in patients with variant angina, it has not been tested by quantitative angiography whether the location of vasospastic activity may change over time.

METHODS

Paired ergonovine provocation tests and coronary angiography were performed at a mean (+/- SD) interval of 43 +/- 13 months apart in patients with persistent symptoms of vasospastic angina in the absence of significant atherosclerosis. A total of 87 spastic and nonspastic segments of 87 major vessels in 29 patients were analyzed by quantitative angiography at baseline, after the administration of ergonovine and after isosorbide dinitrate at the initial and follow-up tests.

RESULTS

In 13 patients (group 1), coronary spasm was observed in the same 16 coronary segments at both the initial and follow-up ergonovine provocation tests. In 16 patients (group 2), the following angiographic changes occurred between the initial and follow-up tests in 48 major vessels: Of the 23 segments that developed spasm at the initial test, 10 did not have spasm at the follow-up test; of the 25 vessels that did not demonstrate spasm on the initial test, 12 demonstrated spasm on the follow-up test (a new site of spasm). Thus, in 22 (46%) of 48 vessels, fluctuation of spastic location was observed at follow-up.

CONCLUSIONS

Quantitative coronary angiography and repeated ergonovine tests revealed that some patients with persistent vasospastic angina demonstrate fluctuation of vasospastic location, whereas others exhibit a fixed location of vasospasm. Vasospastic angina may not only be a transient disease restricted in location, but may also be a persistent and variable condition involving multiple vessels over many years.

Progression and regression of coronary stenosis in the long-term follow-up of vasospastic angina

BACKGROUND

Whether focal vasospasticity plays a pathogenic role in the progression or regression of coronary atherosclerosis is unknown. To determine whether evidence for such a role exists, we studied long-term changes in coronary luminal measurements in patients with vasospastic angina.

METHODS AND RESULTS

Quantitative coronary angiography and repeated ergonovine provocation tests were performed 45 +/- 16 months apart in 30 patients. All patients had vasospastic anginal symptoms and coronary spasm on the initial provocation test. On the 30 patients, 16 had persistent symptoms of vasospastic angina and showed coronary spasm at the same site on the follow-up angiogram (group 1), while the remaining 14 whose vasospastic anginal symptoms disappeared at follow-up demonstrated a negative response to ergonovine on the follow-up tests (group 2). There was no significant difference in patients' baseline characteristics between the two groups. Long-term changes in minimal (MLD) and mean (MEAN) luminal diameter were measured (in millimeters) after administration of isosorbide dinitrate in 19 spastic and 93 nonspastic segments in group 1 and in 17 previously spastic and 81 nonspastic segments in group 2. Both MLD and MEAN were measured in 210 coronary segments of the 30 patients at baseline and after administration of ergonovine and isosorbide dinitrate by use of a computer-based quantitative coronary angiography system. Stenosis progression and regression of individual lesions were defined as a change in MLD of > or = 0.40 mm. In group 1, both the MLD and MEAN of 19 spastic segments were significantly smaller (progression) at follow-up compared with the initial angiogram (MLD, 2.21 +/- 0.54 initially versus 1.95 +/- 0.65 at follow-up, P < .01; MEAN, 2.80 +/- 0.56 initially versus 2.56 +/- 0.58 at follow-up, P < .01), whereas the MLD and MEAN of 93 nonspastic segments in group 1 were not significantly different between the initial and follow-up angiograms (MLD, 2.47 +/- 0.67 initially versus 2.44 +/- 0.69 at follow-up, P = NS; MEAN, 2.96 +/- 0.69 initially versus 2.91 +/- 0.68 at follow-up, P = NS). In group 2, the MLD of the 17 previously spastic segments significantly improved (regression) at follow-up (MLD, 1.99 +/- 0.68 initially versus 2.24 +/- 0.54 at follow-up, P < .05); the MLD and MEAN of the 81 nonspastic segments were not significantly different (MLD, 2.36 +/- 0.59 initially versus 2.39 +/- 0.60 at follow-up, P = NS; MEAN, 2.81 +/- 0.58 initially versus 2.81 +/- 0.61 at follow-up, P = NS). In group 1, significant stenosis progression of individual lesions was observed more frequently at spastic than nonspastic segments (6 of 19 versus 10 of 93, P < .05), whereas stenosis regression was observed in no spastic and 3 nonspastic segments (P = NS). In group 2, stenosis progression was observed at 1 previously spastic segment and 4 nonspastic segments (P = NS), while significant stenosis regression of individual lesions was seen more commonly in previously spastic than nonspastic segments (6 of 17 versus 7 of 81, P < .01).

CONCLUSIONS

These results have demonstrated in patients an association between persistent vasospastic activity and progression of atherosclerosis and an association between cessation of vasospastic activity and regression of atherosclerosis.

In vivo validation of an experimental adaptive quantitative coronary angiography algorithm to circumvent overestimation of small luminal diameters

The reliability of quantitative coronary angiography (QCA) measurements is of fundamental importance for the study and practice of interventional cardiology. In vivo validation results have consistently reported a tendency for QCA systems to overestimate small luminal diameters. Such a systematic error may result in the underestimation of luminal gain during intracoronary procedures and in the underestimation of progression of coronary artery disease during longitudinal studies. We report the in vivo validation results of an experimental adaptive edge-detection algorithm that was developed to reduce overestimation of small luminal diameters by incorporating a dynamic function of variable kernel size of the derivative operator and variable weighting of the first and second derivatives of the brightness profile. The results of the experimental algorithm were compared to those of the conventional parent edge detection algorithm with fixed parameters. Dynamic adjustment of the edge-detection algorithm parameters was found to improve measurements of small (< 0.8-mm) luminal diameters as evidenced by an intercept of +.07 mm for the algorithm with variable weighting compared to +0.21 mm for the parent algorithm with fixed weighting. A slope of < 1 was found for both the parent and experimental algorithms with subsequent underestimation of large luminal diameters. Systematic errors in a QCA system can be identified and corrected by the execution of objective in vivo validation studies and the consequent refinement of edge-detection algorithms. The overestimation of small luminal diameters may be overcome by the incorporation of a dynamic edge-detection algorithm.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary arteriography for quantitative analysis: experimental and clinical comparison of cinefilm and video recordings

Although use of videotape for the recording of coronary angiograms continues to grow, the validity of quantitative coronary angiographic analysis of video images remains unknown. To estimate the reliability of angiographic images recorded on videotape, experimental and clinical angiograms were recorded simultaneously on both 35 mm cinefilm and super-VHS videotape with normal images and with spatial filtering of the images (edge enhancement) on a digital cardiac imaging system. The experimental angiographic studies were performed with plexiglass blocks and stenosis phantom of 0.5 to 3.0 mm in diameter. The clinical angiograms were recorded in 20 patients undergoing percutaneous transluminal coronary angioplasty (31 frames before and 20 frames after percutaneous transluminal coronary angioplasty). The cinefilm and corresponding videotapes were analyzed off-line with the new version of the coronary angiography analysis system. For the experimental study, measurements of minimal luminal diameter obtained from cinefilm, normal-image videotape, and edge-enhanced videotape were compared with the true phantom diameter. In the clinical study the agreement between measurements obtained from cinefilm and measurements from normal-image videotape and edge-enhanced videotape was examined. In the phantom series the accuracy and precision of quantitative coronary angiography measurement for cinefilm were -0.10 +/- 0.08 mm, for normal-image videotape -0.11 +/- 0.18 mm, and for edge-enhanced videotape -0.10 +/- 0.11 mm (mean +/- SD). In the clinical series, the differences between measurements from cinefilm and normal-image videotape were 0.14 +/- 0.20 mm and from cinefilm and edge-enhanced videotape 0.04 +/- 0.13 mm.(ABSTRACT TRUNCATED AT 250 WORDS)