Variability in estimation of coronary dimensions from 6F and 8F catheters

To investigate the suitability of diagnostic 6F catheters for coronary angiographic measures in the clinical setting, we determined the relative accuracy and reproducibility of the measures obtained with these catheters as scaling devices in 59 stenoses. Comparison was made with duplicate injections, obtained before angioplasty, using an 8F guiding catheter as scaling device. Intra- and interobserver variability was evaluated in 15 stenoses. The coefficient of variation averaged 18.3% for the minimal lumen diameter, 10.4% for the percent stenosis, and only 7.4% for the reference diameter. Reproducibility of angiographic measures done with the 6F catheter was similar to that obtained with the 8F catheter, although accuracy was lower with the 6F for the measurement of reference diameter. Thus, quantitative coronary angiography (QCA) measures derived from routine diagnostic angiograms may be suitable for determination of reference diameter, allowing enough precision for determination of the size of a coronary device for intervention, but these measures may lack accuracy for precise determination of minimum diameter and percent stenosis, making their use questionable in studies looking at individual changes in coronary stenosis dimensions. © 1996 Wiley-Liss, Inc.     

Stenting for restenotic lesions with the BARD XT stent

BACKGROUND: Conventional PTCA for the treatment of restenotic lesions is associated with a high rate of recurrence (30-50%). Primary stenting decreases the restenosis rate at long-term follow-up. METHODS: One-hundred consecutive patients with restenosis received a Bard XT stent. Follow-up angiography was performed after 6 months. Angiograms were compared by means of computed quantitative analysis. RESULTS: The mean pretreatment reference diameter was 2.88 +/- 0.51 mm. The mean minimal luminal diameter (MLD) increased from 1.09 +/- 0.57 mm to 2.70 +/- 0.44 mm. The percent diameter stenosis decreased from 66 +/- 13% to 15 +/- 10%. The procedural success rate was 99%. At 6 month follow-up repeat angiography was performed in 86 patients. The mean MLD was 1.74 +/- 0.67 mm with a mean diameter stenosis of 41 +/- 20%. Residual anginal complaints were reported in 29% of patients. In-stent restenosis (defined as diameter stenosis of more than 50%) occurred in 18% of the patients. CONCLUSION: Placement of the Bard XT stent in restenotic lesions is feasible, has an excellent short term outcome and yields a favorable result at 6 month follow-up angiography.     

Feasibility of the PCI through 6F diagnostic catheters.

BACKGROUND: The choice of guiding catheter for optimal back-up support is critical in order to achieve a successful PCI. Diagnostic 6 French (F) catheters have an internal lumen diameter as large as 5F guiding catheters. The aim of this study was to demonstrate for the first time the feasibility of performing PCI with Cordis 6F diagnostic catheters in selected coronary lesions. METHODS: 32 coronary stents were implanted using 6F diagnostic catheters in 27 eligible patients at the Montreal Heart Institute. The inclusion criteria were TIMI angiographic score < B2 in native coronary arteries or in coronary artery bypass grafts. Bifurcations and left main disease were not included. RESULTS: Eighty-five percent of the patients underwent PCI for acute coronary syndromes (ACS). PCI was performed in 5 lesions (19%) of the left coronary circulation; in 21 lesions (78%) of the right coronary artery and in one lesion (4%) of the 1st obtuse marginal branch of the circumflex artery, through a left mammary artery bypass. Only stents suitable for 5F guiding catheters were used. The largest stent was 4.0 mm in diameter and 32 mm in length. Direct stenting was performed in 75% of patients. The angiographic success for PCI of target lesions was 100%, without clinical or angiographic complications. CONCLUSIONS: In selected cases, diagnostic 6F catheters can be used for PCI with 5F compatible balloons and stents. PCI via a diagnostic catheter may provide even better back-up support and allows for significant resources and time savings, especially in patients with ACS.     

Comparison of coronary stenosis quantitation results from on-line digital and digitized cine film images

To examine the effects of digital image acquisition mode and subtraction techniques on the results of coronary stenosis quantitation, 100 discrete lesions from 45 patients undergoing routine diagnostic angiography were analyzed in each of 3 image types: direct on-line digital, electrocardiogram-gated digital subtraction and digitized cine film images. For the geometric measurements (minimal lumen diameter and percent diameter stenosis) correlation coefficients for 2-way comparisons among the image types ranged from 0.90 to 0.96. Linear regression slopes ranged from 0.93 to 1.00, with intercepts from 0.03 to 0.07 mm for minimal diameter and -0.5 to 4.4% for percent diameter stenosis. For the videodensitometric percent area stenosis data, the correlation coefficients ranged from 0.80 to 0.89, with linear regression slopes from 0.84 to 0.89 and intercepts from 8.3 to 12.8%. Thus, the results of quantitative geometric measurements of coronary stenosis severity were not strongly affected by image acquisition mode (on-line versus cine film digitization) or by electrocardiogram-gated digital subtraction, while densitometric data correlated less well when on-line digital and digitized cine film acquisition methodology were compared.     

Accuracy and reproducibility of quantitative coronary arteriography using 6 and 8 French catheters with cine angiographic acquisition

To determine the suitability of 6 French catheters for quantitative coronary arteriography, the relative accuracy and reproducibility of one type of these catheters was compared to that obtained with standard 8 French catheters in 20 stenoses. Duplicate injections with polyurethane 6 French catheters were obtained using hand and power injection technique with cineangiographic acquisition (four 6 French catheter injections total per stenosis). Measurements of both percent diameter stenosis and absolute dimensions were compared to those obtained with hand injection and cine acquisition using 8 French catheters as a "gold standard." While the reproducibility of dimension determination with the 6 French catheter was generally similar to that obtained with the 8 French catheter (0.27 +/- 0.23 mm for absolute diameter and 8.1 +/- 7.4% for percent diameter stenosis), accuracy was significantly less for the 6 French catheter for measurement of absolute dimensions. Thus, while apparently well suited for serial measurements of the same stenoses, 6 French catheters may not be as accurate in the determination of absolute artery dimensions as 8 French catheters.     

Impact of catheter size on reliability of quantitative coronary angiographic measurements (comparison of 4Fr and 6Fr catheters)

To evaluate the feasibility of catheter down sizing for QCA, the reliability of a 4Fr catheter as a calibration device was evaluated. Repeated coronary angiograms of 9 lesions were obtained using 4Fr and 6Fr catheters under otherwise identical conditions. The calibration factor was measured 10 times by 4Fr and 6Fr catheters. QCA measurements including minimal lumen diameter (MLD), interpolated normal reference (Int N), percent diameter stenosis (%DS), and lesion length (LL) were performed by two technicians twice with a 3-month interval. The intraobserver and interobserver variability of each parameter was evaluated using intraclass correlation coefficients (ICCs). Mean of mean SD of calibration factor was significantly larger in 4Fr than in 6Fr in 9 lesions. The mean of mean coefficient of variance was significantly larger in 4Fr catheters vs in 6Fr catheters. A 6Fr catheter showed excellent reliability for both intraobserver and interobserver variability in MLD, Int N, %DS, and LL. In contrast, 4Fr showed that reliability in intraobserver variability depended on the analyst. Although reliability of interobserver variability in Int N measured by the 4Fr catheter was >0.80, the value was less than that by the 6Fr catheter. Taking these results into consideration, 4Fr catheters are less reliable than 6Fr catheters when measuring QCA data especially for follow-up data that need most accurate measurements of MLD and %DS. It would be better to use a 6Fr catheter to evaluate QCA measurements such as acute gain, late loss, restenosis rate, and device size.     

Efficacy of a new angioplasty catheter for severely narrowed coronary lesions

Conventional over the wire dilation catheters may be unsuccessful in crossing coronary lesions that are severely narrowed. Hence, a new, extremely low profile coronary angioplasty catheter specifically designed to dilate such lesions was investigated. The catheter features a 2.0, 2.5 or 3.0 mm (inflated diameter) balloon mounted on a guide wire. The deflated profile of the 2.0 mm balloon measures 0.020 +/- 0.001 in. (0.51 +/- 0.03 mm). The catheter can be used in conjunction with 7F angiographic or 8F guide catheters. The catheter was used in 61 patients, aged 43 to 86 years, with predominantly Canadian Cardiovascular Society class III-IV angina. Dilation was attempted in 77 lesions. Lesion length averaged 5.7 +/- 3.1 mm (mean +/- 1 SD), minimal diameter 0.51 +/- 0.25 mm and internal vessel diameter 2.27 +/- 0.43 mm. Sixty lesions (78%) were successfully dilated to less than 50% residual stenosis with this catheter alone; nine lesions were further dilated with a larger balloon catheter. The new catheter was unable to cross 13 lesions (17%); only 2 of these lesions were subsequently crossed with a conventional over the wire system. On the other hand, the catheter was used after failure of conventional dilating catheters in 21 lesions and was successful in 16. The new catheter was particularly valuable for distal lesions and those demonstrating 90 to 99% diameter reduction. For all lesions crossed, stenosis decreased from 76 +/- 11 to 29 +/- 12% after 2.9 +/- 2.7 inflations and peak inflation pressure of 8.0 +/- 2.9 bar. Complications were rare; coronary occlusion occurred in two lesions (3%) and dissection in three lesions (4%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Immediate changes in stenosis geometry following stent implantation: comparison between a self-expanding and a balloon-expandable stent

The immediate changes in stenosis geometry following Wallstent and Wiktor stent implantation in native coronary arteries were compared in 92 patients (46 in each group) using automated edge detection. Patients with comparable baseline stenosis characteristics were selected. Lesions were matched for lesion site, reference diameter, and minimal luminal diameter. In both groups, the stented coronary artery was the left anterior descending artery in 27 patients (59%), the left circumflex artery in four patients (9%), and the right coronary artery in 15 patients (33%). The baseline reference diameter was 2.86 +/- 0.39 mm and 2.87 +/- 0.42 mm in the Wallstent and Wiktor stent study group, respectively (NS). The baseline minimal luminal diameter was identical in both groups (1.13 +/- 0.24 mm). The nominal size (mean +/- SD) of the unconstrained Wallstent was 3.5 +/- 0.3 mm and 3.3 +/- 0.3 mm for the Wiktor stent (P less than 0.05). Both types of stents resulted in a similar increase in minimal luminal diameter immediately following implantation (Wallstent: 2.34 +/- 0.38 mm, Wiktor stent: 2.43 +/- 0.27 mm, NS). Furthermore, there was a similar decrease in diameter stenosis and increase in minimal luminal cross-section area following implantation of both stents. These morphological changes were associated with a normalization of the hemodynamic parameters in both groups. It is concluded that, although the Wallstent and Wiktor stent are different in design and mechanical characteristics, there is a similar immediate improvement in stenosis geometry following implantation of both devices.     

Comparison of two- and three-dimensional quantitative coronary angiography to intravascular ultrasound in the assessment of intermediate left main stenosis

Angiographic evaluation of intermediate left main coronary artery stenosis (LMS) is often limited. Three-dimensional (3D) quantitative coronary angiography has recently developed to overcome 2-dimensional (2D) quantitative coronary angiographic (QCA) limitations. In patients with angiographically intermediate LMS, we investigated whether 3D quantitative coronary angiography was superior to 2D quantitative coronary angiography in predicting the presence of a significant LMS, defined as a minimum luminal area <6 mm(2) at intravascular ultrasound (IVUS). 2D and 3D quantitative coronary angiography were compared in their measurements of minimum luminal area, percent area stenosis, minimum luminal diameter, and percent diameter stenosis and in their prediction of an IVUS minimum luminal area <6 mm(2). In total 58 target lesions were interrogated, 25 (43%) of which had an IVUS minimum luminal area <6 mm(2). Correlation between 3D-QCA minimum luminal area and IVUS minimum luminal area was stronger than the correlation between 2D-QCA minimum luminal area (or minimum luminal diameter) and IVUS minimum luminal area (R = 0.67, p = 0.0001, and R = 0.40, p = 0.001, respectively, p = 0.04 for comparison). To predict IVUS minimum luminal area <6 mm(2), the most accurate 2D-QCA measurement was minimum luminal diameter (area under curve 0.81, cutoff 2.2 mm, p = 0.0001), and the most accurate 3D-QCA measurement was minimum luminal area (area under curve 0.86, cutoff 5.6 mm(2), p = 0.0001). 2D-QCA percent diameter stenosis did not significantly predict IVUS minimum luminal area <6 mm(2) (area under curve 0.56, cutoff 38%, p = 0.45). In conclusion, the accuracy of quantitative coronary angiography in predicting LM IVUS minimum luminal area <6 mm(2) is limited. When IVUS is not available or contraindicated, 3D quantitative coronary angiography may assist in the evaluation of intermediate LMS. Among 2D-QCA parameters, minimum luminal diameter is more accurate than percent diameter stenosis in predicting significant LMS.     

Coronary angiography using 4 French catheters with power injection: a randomized comparison with 6 French catheters

BACKGROUND: Coronary angiography using 4 F catheters may reduce access-site complications and enable early ambulation, although earlier studies suggested that the quality of images may be an issue of concern. METHODS AND RESULTS: To ascertain the quality of angiographic images and safety of early ambulation, 500 patients were randomized to coronary angiography with either 4 F or 6 F catheters. Procedural characteristics, angiographic quality scores and results of ambulation were analyzed in the two groups. Patients in the 4 F group were mobilized at 2 hours post-procedure while those in the 6 F group were ambulated at 6 hours. There was no procedure-related complication in either group. The procedure was successfully completed in 250 of 252 patients randomized to the 4 F group. In two patients in the 4 F group, sheaths were upgraded to 6 F to complete the procedure, as difficulty was encountered in hooking the coronary ostium with a 4 F Judkin's catheter. Coronary angiographic quality scores in these two groups were comparable. Angiographic scores for the 4 F and 6 F groups for the left coronary artery averaged 4.45+/-0.5 and 4.58+/-0.3 (p>0.1), respectively. The right coronary artery scores averaged 4.30+/-0.4 and 4.35+/-0.2 (p>0.1) in the 4 F and 6 F groups. Angiographic scores for the left ventricular angiogram averaged 4.22+/-0.1 and 4.44+/-0.3 (p>0.1) in the 4 F and 6 F groups, respectively. None of the angiograms were assigned a score of <3.0 (not diagnostic). The total contrast volume consumed in the two groups was also equivalent. There were no groin-related complications in the 4 F group although these patients were ambulated 2 hours after the procedure. CONCLUSIONS: Coronary angiography performed with a 4 F catheter is a safe and reliable procedure. The quality of image obtained with a 4 F catheter is equivalent to that obtained with a 6 F catheter. Early ambulation at 2 hours is feasible without compromising safety.     

Influence of balloon size and stenosis morphology on immediate and delayed elastic recoil after percutaneous transluminal coronary angioplasty.

After successful coronary angioplasty, the minimal luminal diameter of the dilated coronary artery segment is generally smaller than the diameter of the largest balloon catheter at the maximal inflation pressure. The determinants of this phenomenon were studied in 28 patients. Biplane angiograms were obtained after intracoronary administration of isosorbide dinitrate (1 mg) before, immediately and 24 h after coronary angioplasty. Balloon and coronary luminal diameters were measured by automated contour detection. Immediately after the procedure, the difference between inflated balloon diameter and minimal luminal diameter averaged 0.93 +/- 0.43 mm for the entire group and was greater both in eccentric stenoses (1.13 +/- 0.39 vs. 0.70 +/- 0.36 mm; p less than 0.01) and after angioplasty with an oversized balloon (1.20 +/- 0.37 vs. 0.71 +/- 0.33 mm; p less than 0.005). At 24 h, the balloon - minimal luminal diameter difference was unchanged at the group level (0.86 +/- 0.38 mm, but the minimal luminal diameter increased significantly in the subgroup of coronary segments dilated with an oversized balloon (1.97 +/- 0.37 vs. 1.81 +/- 0.28 mm; p less than 0.05). Thus, the difference between the minimal diameter of a dilated coronary segment immediately after a successful coronary balloon angioplasty procedure and the maximal diameter of the inflated balloon catheter is dependent both on eccentricity of the stenosis and on the balloon/artery diameter ratio. Moreover, the increase in minimal luminal diameter 24 h after angioplasty performed with an oversized balloon suggest that in addition to elastic recoil partly reversible factors related to vessel barotrauma are involved.     

Decreasing length of stay in the hospital by coronary angiography with 5-French catheters

The use of 5-French (F) coronary angiography catheters as opposed to 7-F may reduce arterial injury at the puncture site. Therefore, a decrease in time to recuperation after coronary angiography with the Judkins technique seems possible. In 199 patients undergoing coronary angiography with 5-F catheters, management, imaging, and complications were investigated. In 18 patients the diagnosis of a valvular defect was confirmed; in 128 patients coronary artery disease (lesions greater than 70%) was found. Three patients had idiopathic dilative cardiomyopathy. Coronary lesions of less than 70% with normal left ventricular function were found in 50 patients ("normals"). After coronary angiography with 5-F catheters bedrest was recommended for 4 h, as compared to 24 h after a 7-F catheter procedure. Successful coronary artery imaging with 5-F catheters was achieved in 168 patients (84%). In 31 patients (27 coronary artery disease, 1 aortic stenosis, 3 normals) selective imaging was not achieved, and the 5-F catheter had to be replaced by a 7-F catheter. Aortic (systolic 147 +/- 24 vs 132 +/- 20 mm Hg, p = 0.002; diastolic 74 +/- 13 vs 70 +/- 11, p = 0.05) and left ventricular pressures (systolic 149 +/- 26 vs 131 +/- 20 mm Hg, p = 0.001; enddiastolic 18 +/- 8 vs 14 +/- 8 mm Hg, p = 0.035) were higher in this group, whereas no relations to age, sex, and diagnosis emerged.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relation of quantitative coronary lesion measurements to the development of exercise-induced ischemia assessed by exercise echocardiography

To assess the relation of quantitative measures of coronary stenoses to the development of exercise-induced regional wall motion abnormalities, 34 patients with isolated, single vessel coronary artery lesions and normal wall motion at rest underwent exercise echocardiography and quantitative angiography on the same day. Although all 11 patients with a visually estimated stenosis greater than or equal to 75% had an ischemic response and 10 (91%) of 11 patients with a less than or equal to 25% visually estimated stenosis had a normal response by exercise echocardiography, among 12 patients with a visually estimated stenosis of 50%, 6 (50%) had an ischemic response and 6 (50%) had a normal exercise echocardiogram. Quantitative measurements of stenosis severity distinguished patients with ischemic (group 1) from normal (group 2) exercise echocardiographic responses as follows: minimal luminal diameter (mm), group 1 1.0 +/- 0.4 versus group 2 1.7 +/- 0.4, p less than 0.0001; minimal cross-sectional area (mm2), group 1 0.9 +/- 0.6 versus group 2 2.5 +/- 1.1, p less than 0.0001; percent diameter stenosis, group 1 68.3 +/- 14.2 versus group 2 42.2 +/- 12.1, p less than 0.0001; and percent area stenosis, group 1 87.5 +/- 7.8 versus group 2 64.8 +/- 15.9, p less than 0.0001. These data validate the utility of exercise echocardiography by demonstrating that 1) coronary stenosis severity measured by quantitative angiography is closely related to wall motion abnormalities detected by exercise echocardiography, and 2) exercise echocardiography can be used as a noninvasive means to assess the physiologic significance of coronary artery lesions.     

Alterations in reference vessel diameter following intracoronary stent implantation: Important consequences for restenosis based on percent diameter stenosis

The scaffolding effect of stent implantation has the potential to alter vascular geometry and dimensions. The objective of this study was to determine the impact of intracoronary stent implantation on the reference vessel diameter and the consequences of this on the frequency of restenosis applying the binary definitions of restenosis based on percent diameter stenosis. Routine angiographic follow-up was performed in 79/80 consecutive patients who had a single elective Palmaz-Schatz stent implanted in denovo lesions in native coronary arteries 6.5±3.4 mo after the index procedure. Complete quantitative angiographic follow-up was available in 78 (98%). The mean reference vessel diameter was 2.9±0.6 mm preprocedure, increased to 3.1±0.5 mm immediately poststent implantation and was 2.6±0.6 mm at follow-up (F = 6.45, P = 0.0001, ANOVA for repeated measures). In view of the varying reference vessel diameter, percent diameter stenosis postangioplasty and at follow-up was determined by two methods: (1) automatically by the quantitative coronary angiographic analysis system and (2) by expressing the minimal luminal diameter postangioplasty and at follow-up as a function of the original preprocedural reference vessel diameter. The restenosis rate was significantly greater for all definitions of restenosis when the minimal luminal diameter was determined as a function of the original preprocedure reference vessel diameter (e.g., 34% vs. 18% for the ?50% criterion, P = 0.018). Stent implantation results in alterations in reference vessel diameter, which have important consequences for the frequency of restenosis presented as a binary variable based on percent diameter stenosis. © 1995 Wiley-Liss, Inc.     

Accuracy of individual and panel visual interpretations of coronary arteriograms: implications for clinical decisions

The visual interpretation of coronary arteriograms by individuals has been shown to be variable and inaccurate. To determine whether observer accuracy improves with experience or with use of the mean values obtained from a panel of observers, the visual readings of percent diameter stenosis and "normal" reference segment diameter were compared with the quantitative analyses of 13 randomly chosen coronary stenoses. Visual interpretation was also performed on cineangiograms of seven phantom stenoses ranging in severity from 17% to 83%. Repeated quantitative arteriography demonstrated good intraobserver variability for minimal stenosis diameter (r = 0.91, SD = 0.23 mm) and percent diameter stenosis (r = 0.93, SD = 6.4%). When the mean of the repeated quantitative analyses was used as the standard, visual interpretations of percent diameter stenosis were found to have considerable inaccuracy (r = 0.78, SD = 14.5%). Phantom percent diameter stenosis data were better correlated (r = 0.85), but accuracy remained poor (SD = 17.8%). Fifty percent narrowings were read over a range from 30% to 95%. Substantial inaccuracies were also found for observer assessment of normal reference segment diameter (r = 0.75, SD = 0.75 mm). Observer accuracy of percent stenosis did not correlate with prior angiographic experience but was progressively improved by taking the mean value of the interpretations of three and five experienced angiographers (r = 0.88, 0.89; SD = 11.3%, 8.3%, respectively). These findings suggest that arteriographic interpretations accurate enough for interventional decisions can only be obtained using quantitative arteriography or the mean value of data from a large panel of angiographers.     

Reproducibility of quantitative coronary analysis

Because of limited storage capacity for digital images, angiographic laboratories without cinefilm are dependent on locally performed quantitative coronary angiography (QCA) in clinical studies. In the present study the intra-and interobserver variability, as well as variability between different laboratories and variability due to frame selection was analyzed. A total of 20 coronary lesions were studied in two different digital laboratories 12±8 days apart. Images were analyzed on-line and after being transferred to a Cardiac Work Station (CWS). There was no significant difference between the measurement situations. For minimal luminal diameter (MLD) precision (SD of signed errors) ranged from 0.12 mm to 0.20 mm, for reference diameter (RD) from 0.15 mm to 0.28 mm, and for percent diameter stenosis (DS) from 4.2% to 5.8%. Overall relative precision was obtained by normalizing the QCA parameters, and was 11.9% for MLD, 7.0% for RD and 8.5% for DS (p<0.001, RD and DS compared to MLD). The overall variability in the interobserver and in the interlaboratory comparisons was 11.2% and 10.4%, respectively (n.s.) (n.s.). Thus the variability of QCA performed in cinefilmless, digital laboratories is small, and within a range making it an useful tool for clinical practice and group comparisons in clinical studies. However, the error range of QCA measurements must be taken into consideration when judging results from individual patients.     

Prediction of the physiologic significance of coronary arterial lesions by quantitative lesion geometry in patients with limited coronary artery disease

Studies in animals with normal coronary arteries have shown that coronary flow reserve can be predicted by angiographic measurements of arterial stenosis. Studies in man, however, suggest that even quantitative analysis of coronary angiograms cannot predict the physiologic significance of individual coronary lesions. These studies, however, were carried out in patients with either widespread, diffuse coronary artery disease or by measurement techniques that tend to underestimate maximal coronary flow reserve. To determine the relationship between coronary arterial stenosis and coronary flow reserve (CFR) in patients with discrete limited coronary atherosclerosis, we studied 50 patients with a single discrete coronary stenosis in only one or two vessels. The minimum coronary arterial cross-sectional area (mCSA), percent area stenosis (%AS), and percent diameter stenosis in the left and right anterior oblique projections were determined by the Brown/Dodge method of quantitative coronary angiography. A No. 3F coronary Doppler catheter was placed immediately proximal to the lesion. Measurements of CFR were obtained by intracoronary administration of papaverine in doses sufficient to provide maximal arteriolar vasodilation. In 25 patients, a translesional pressure gradient was obtained with an angioplasty catheter. CFR measured in patients with coronary artery disease was compared with that in 13 patients with normal coronary vessels. In normal patients, CFR averaged 5.0 +/- 0.6 (peak/resting velocity ratio; mean +/- SEM, range 3.7 to 8.2). In patients with limited coronary artery disease, CFR was closely correlated with %AS (r = .85), mCSA (r = .79), and the translesional pressure gradient (r = .83). Additionally, the most severe percent diameter stenosis in either the left or right anterior oblique view was also highly correlated with CFR (r = .82). Importantly, all arteries with lesions producing less than 70% area stenosis and less than 50% diameter stenosis, or with greater than 2.5 mm2 mCSA had CFR of over 3.5. These results suggest that, in contrast to the poor correlation of percent area and percent diameter stenosis to CFR measured in patients with multivessel coronary artery disease, CFR measured at angiography in patients with discrete, limited coronary artery disease correlates closely with luminal stenosis determined precisely with quantitative coronary angiography. Differences in the extent of diffuse arterial narrowing may account for these discrepancies.     

Percutaneous coronary excimer laser-assisted balloon angioplasty: initial clinical and quantitative angiographic results in 50 patients

The initial clinical experience and quantitative angiographic results of percutaneous coronary excimer laser-assisted balloon angioplasty are described for 55 lesions in 50 patients. With use of a xenon chloride (308 nm) excimer laser generator and 1.5 to 1.75 mm catheters, excimer laser angioplasty was attempted at 135 ns pulse width, 25 to 40 Hz repetition rate, 2 to 5 s laser delivery time and 30 to 60 mJ/mm2 energy fluence. Laser success (greater than 20% reduction in absolute percent diameter stenosis) was achieved in 41 (75%) of 55 lesions, with 100% subsequent balloon angioplasty success (less than 50% residual stenosis). By quantitative digital caliper technique, the percent diameter stenosis (mean +/- SE) was reduced from 81 +/- 1% to 50 +/- 3% after excimer laser angioplasty (p less than 0.001) and to 20 +/- 1% after balloon angioplasty (p less than 0.001); minimal luminal diameter increased from 0.56 +/- 0.04 to 1.46 +/- 0.08 mm (p less than 0.001) and 2.03 +/- 0.07 mm (p less than 0.001), respectively. By videodensitometric techniques, the percent area stenosis decreased from 86 +/- 2% to 54 +/- 3% after excimer angioplasty (p less than 0.001) and to 26 +/- 3% after balloon angioplasty (p less than 0.001). There were no perforations, need for emergency bypass surgery or deaths. The overall incidence of abrupt closure (3.6%), dissection (1.8%), embolization (1.8%), filling defect (6%), myocardial infarction (5.5%), side branch occlusion (3.6%) or spasm (3.6%) was infrequent and more related to subsequent balloon angioplasty than to the laser procedure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Elastic recoil following percutaneous transluminal coronary angioplasty and Palmaz-Schatz stent implantation

The post-procedural elastic recoil in 133 lesions treated with the Palmaz-Schatz stent was compared to 133 matched lesions treated with balloon angioplasty to determine the role of prevention of elastic recoil in the creation of a larger initial luminal diameter. Elastic recoil was defined as the difference between the maximal diameter of the inflated balloon and the minimal luminal diameter of the dilated segment immediately after the procedure and was evaluated by quantitative coronary angiography. Overdilatation was defined as a dilatation induced by a balloon with a maximal diameter larger than the pre-procedure reference diameter. The percent diameter stenosis was reduced from 73% to 31% in the balloon angioplasty group and from 72% to -4% in the stent group (31% vs. -4%, p < 0.01). Elastic recoil was significantly larger in the balloon angioplasty group than in the stent group (0.94 +/- 0.29 mm vs. 0.09 +/- 0.09 mm, p < 0.01). Overdilatation and lesion morphology had no significant effects on elastic recoil in the stent group. In the balloon angioplasty group, overdilatation, noncalcified lesions and eccentric lesions were associated with increased elastic recoil. These results indicated that the larger post-procedural luminal diameter associated with the Palmaz-Schatz stent was primarily the result of prevention of elastic recoil, which was not influenced by the degree of overdilatation or lesion morphology.     

Paclitaxel-eluting stent Taxcor: first application in man

AIM: The safety and efficacy of the second-generation paclitaxel-eluting stent with bioactive matrix Taxcor after implantation in de novo coronary lesions at 6 months is unknown. METHODS: In this single-center non-controlled study, 45 patients with mean de novo coronary lesions of 12.1+/-1.9 mm in length and mean reference diameter of 2.9+/-0.3 mm received the paclitaxel-eluting stent (Taxcor). Fifty stents were implanted. Clinical and angiographic follow-up were performed after 6 months. It was the first time that the Taxcor stent was applied in patients. RESULTS: Mean stent diameter was 3.0+/-0.3 mm and mean length 21.2+/-5.9 mm. Four patients did not consent to control angiography at 6 months. Mean minimal lumen diameter increased from 1.1+/-0.1 mm (pre-stent) to 2.7+/-0.3 mm (post-stent) and had slightly decreased to 2.4+/-0.6 mm at 6-month follow-up. Mean acute lumen gain was 1.6+/-0.3 mm. Mean reference-vessel diameter was 2.9+/-0.3 mm at all time points. Mean percentage-diameter stenosis decreased from 62.6%+/-5.6 (pre-stent) to 9.1+/-6.0% (post-stent) and had increased slightly to 18.4+/-6.5% after 6 months. Mean late lumen loss was 0.3+/-0.4 mm. All patients remained symptom-free during the 6-month follow-up with no cases of acute myocardial infarction or death reported. No procedure-related complications occurred and no acute or subacute stent thromboses were reported. Control angiography showed binary restenosis (percentage-diameter stenosis >50%) in one patient, in whom coronary intervention was performed subsequently. CONCLUSION: The paclitaxel-eluting stent Taxcor appeared to be effective and safe up to 6 months following implantation.