Quantitative Coronary Angiography Parameters Research Articles

Angiography-Based Superficial Wall Strain of De Novo Stenotic Coronary Arteries: Serial Assessment of Vessels Treated with Bioresorbable Scaffold or Drug-Eluting Stent

ObjectivesThis study sought to present an angiography-based computational model for serial assessment of superficial wall strain (SWS, dimensionless) of de-novo coronary stenoses treated with either bioresorbable scaffold (BRS) or drug-eluting stent (DES). BackgroundA novel method for SWS allows the assessment of the mechanical status of arteries in-vivo, which may help for predicting cardiovascular outcomes. MethodsPatients with arterial stenosis treated with BRS (n = 21) or DES (n = 21) were included from ABSORB Cohort B1 and AIDA trials. The SWS analyses were performed along with quantitative coronary angiography (QCA) at pre-PCI, post-PCI, and 5-year follow-up. Measurements of QCA and SWS parameters were quantified at the treated segment and adjacent 5-mm proximal and distal edges. ResultsBefore PCI, the peak SWS on the ‘to be treated’ segment (0.79 ± 0.36) was significantly higher than at both virtual edges (0.44 ± 0.14 and 0.45 ± 0.21; both p < 0.001). The peak SWS in the treated segment significantly decreased by 0.44 ± 0.13 (p < 0.001). The surface area of high SWS decreased from 69.97mm2 to 40.08mm2 (p = 0.002). The peak SWS in BRS group decreased to a similar extent (p = 0.775) from 0.81 ± 0.36 to 0.41 ± 0.14 (p < 0.001), compared with DES group from 0.77 ± 0.39 to 0.47 ± 0.13 (p = 0.001). Relocation of high SWS to device edges was often observed in both groups after PCI (35 of 82 cases, 41.7 %). At follow-up of BRS, the peak SWS remained unchanged compared to post-PCI (0.40 ± 0.12 versus 0.36 ± 0.09, p = 0.319). ConclusionAngiography-based SWS provided valuable information about the mechanical status of coronary arteries. Device implantation led to a significant decrease of SWS to a similar extent with either polymer-based scaffolds or permanent metallic stents.

Quantitative flow ratio to predict long-term coronary artery bypass graft patency in patients with left main coronary artery disease

PurposeFractional flow reserve (FFR) has been demonstrated in some studies to predict long-term coronary artery bypass graft (CABG) patency. Quantitative flow ratio (QFR) is an emerging technology which may predict FFR. In this study, we hypothesised that QFR would predict long-term CABG patency and that QFR would offer superior diagnostic performance to quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS).MethodsA prospective study was performed on patients with left main coronary artery disease who were undergoing CABG. QFR, QCA and IVUS assessment was performed. Follow-up computed tomography coronary angiography and invasive coronary angiography was undertaken to assess graft patency.ResultsA total of 22 patients, comprising of 65 vessels were included in the analysis. At a median follow-up of 3.6 years post CABG (interquartile range, 2.3 to 4.8 years), 12 grafts (18.4%) were occluded. QFR was not statistically significantly higher in occluded grafts (0.81 ± 0.19 vs. 0.69 ± 0.21; P = 0.08). QFR demonstrated a discriminatory power to predict graft occlusion (area under the receiver operating characteristic curve, 0.70; 95% confidence interval [CI], 0.52 to 0.88; P = 0.03). At long-term follow-up, the risk of graft occlusion was higher in vessels with a QFR > 0.80 (58.6% vs. 17.0%; hazard ratio, 3.89; 95% CI, 1.05 to 14.42; P = 0.03 by log-rank test). QCA (minimum lumen diameter, lesion length, diameter stenosis) and IVUS (minimum lumen area, minimum lumen diameter, diameter stenosis) parameters were not predictive of long-term graft patency.ConclusionsQFR may predict long-term graft patency in patients undergoing CABG.

Impact of Absorb bioresorbable scaffold implantation technique on post-procedural quantitative coronary angiographic endpoints in ST-elevation myocardial infarction: a sub-analysis of the BVS STEMI STRATEGY-IT study.

The aim of the study was to evaluate the impact of bioresorbable vascular scaffold (BRS) implantation technique on post-procedural quantitative coronary angiography (QCA) parameters in ST-elevation myocardial infarction (STEMI). We assessed 442 STEMI patients who underwent BRS implantation in the BVS STEMI STRATEGY-IT study. Optimal BRS implantation was assessed using the PSP score, developed and validated in the GHOST-EU registry. We analysed post-implantation QCA parameters, including minimum lumen diameter (MLD) and maximum footprint, in patients with and without optimal BRS implantation, coded as maximum PSP score. Patients with optimal BRS implantation had higher post-procedural MLD and lower maximum footprint than those without. Multivariate analysis demonstrated that optimal BRS implantation was an independent predictor of high post-procedural MLD, defined as ≥2.4 mm for 2.5 or 3.0 mm BRS and ≥2.8 mm for 3.5 mm BRS. Thrombectomy before optimal BRS implantation showed a trend towards higher post-procedural MLD and lower maximum footprint. There was no relationship between optimal BRS implantation and device-oriented composite events at one year. Optimal BRS implantation, as assessed by PSP score, was associated with better post-procedural QCA parameters in STEMI. Thrombectomy before optimal BRS implantation might improve angiographic results in STEMI. Long-term follow-up is needed to analyse the relationship between QCA parameters and clinical outcomes after BRS implantation in STEMI patients.

Incremental Value of Subtended Myocardial Mass for Identifying FFR-Verified Ischemia Using Quantitative CT Angiography: Comparison With Quantitative Coronary Angiography and CT-FFR

ObjectivesThis study examined the incremental value of subtended myocardial mass (Vsub) as assessed by coronary computed tomography angiography (CTA) for identifying lesion-specific ischemia verified by invasive fractional flow reserve (FFR) in quantitative coronary CTA. BackgroundFFR is determined not only by coronary stenosis severity, but also by Vsub. One-step evaluation of combined Vsub and coronary lesion morphology may improve the accuracy of coronary CTA for identifying ischemia-producing lesions. MethodsA total of 246 intermediate coronary artery lesions (30% to 80% diameter stenosis) in 220 patients (mean age 61.7 years, 168 men) interrogated by FFR were retrospectively studied. Coronary CTA data were used to assess the Vsub by coronary artery stenosis, minimal lumen area (MLA), percentage of aggregated plaque volume (%APV), positive remodeling, and low-attenuation plaque. The ability of Vsub/MLA2 to discriminate lesions with FFR ≤0.80 was examined. Diagnostic performance, odds ratios, and category-less net reclassification improvements of coronary CTA parameters for FFR-verified (≤0.80) ischemia were evaluated. On-site computed tomography (CT) derived–FFR (CT-FFR) and quantitative coronary angiography (QCA) data were also compared. ResultsOf 246 lesions, 84 (34.1%) showed an FFR ≤0.80. Vsub was independently associated with an FFR ≤0.80 (odds ratio: 1.04/1 cm3; p = 0.032) and showed incremental value over MLA. Vsub/MLA2 >4.16 was the best single parameter for discriminating an FFR ≤0.80 with 83.3% sensitivity and 67.9% specificity. The area under the curve (AUC) of Vsub/MLA2 >4.16 (0.80 [95% confidence interval: 0.75 to 0.85]) was better than that of MLA (change in [Δ]AUC: 0.069; p < 0.001), %APV (ΔAUC: 0.096; p = 0.017), and diameter stenosis of QCA (ΔAUC: 0.080; p = 0.037) and was comparable to that of CT-FFR (AUC 0.77; ΔAUC: 0.035; p = 0.304). ConclusionsVsub is an independent determinant of an FFR ≤0.80. The mathematical index of Vsub/MLA2 >4.16 assessed by coronary CTA shows better diagnostic performance for the detection of ischemia-producing lesions than CT-derived MLA alone or %APV and QCA parameters and was comparable to that of on-site CT-FFR.

Relationship Between Coronary Contrast-Flow Quantitative Flow Ratio and Myocardial Ischemia Assessed by SPECT MPI

PurposeA new method has been developed to calculate fractional flow reserve (FFR) from invasive coronary angiography, the so-called “contrast-flow quantitative flow ratio (cQFR)”. Recently, cQFR was compared to invasive FFR in intermediate coronary lesions showing an overall diagnostic accuracy of 85%. The purpose of this study was to investigate the relationship between cQFR and myocardial ischemia assessed by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI).MethodsPatients who underwent SPECT MPI and coronary angiography within 3 months were included. The cQFR computation was performed offline, using dedicated software. The cQFR computation was based on 3-dimensional quantitative coronary angiography (QCA) and computational fluid dynamics. The standard 17-segment model was used to determine the vascular territories. Myocardial ischemia was defined as a summed difference score ≥2 in a vascular territory. A cQFR of ≤0.80 was considered abnormal.ResultsTwo hundred and twenty-four coronary arteries were analysed in 85 patients. Overall accuracy of cQFR to detect ischemia on SPECT MPI was 90%. In multivariable analysis, cQFR was independently associated with ischemia on SPECT MPI (OR per 0.01 decrease of cQFR: 1.10; 95% CI 1.04-1.18, p = 0.002), whereas clinical and QCA parameters were not. Furthermore, cQFR showed incremental value for the detection of ischemia compared to clinical and QCA parameters (global chi square 48.7 to 62.6; p <0.001).ConclusionsA good relationship between cQFR and SPECT MPI was found. cQFR was independently associated with ischemia on SPECT MPI and showed incremental value to detect ischemia compared to clinical and QCA parameters.

Stenotic flow reserve derived from quantitative coronary angiography has modest but incremental value in predicting functionally significant coronary stenosis as evaluated by fractional flow reserve.

Stenotic flow reserve (SFR) derived from quantitative coronary angiography (QCA) has been correlated with myocardial ischaemia as determined by pharmacological stress echocardiography. However, the diagnostic accuracy of SFR in predicting functionally significant coronary stenosis as assessed by the gold standard, fractional flow reserve (FFR), has not been previously characterised. Patients who underwent coronary angiography and FFR assessment between January 2010 and February 2012 in a single tertiary centre were retrospectively assessed. QCA parameters such as minimal lumen diameter (MLD), lesion length, diameter stenosis (DS), SFR, turbulent resistance (TR) and Poiseuille resistance (PR) were assessed. Significant FFR was defined as FFR ≤0.8. The diagnostic accuracy of QCA parameters to predict significant FFR was assessed by independent t-test and receiver operator characteristic (ROC) curve. Statistical significance was defined as P value of <0.05. The study included 272 patients (age: 64±11, 70% males) and 415 vessels. There were 180 (43%) vessels which were FFR significant. The mean FFR value for all vessels was 0.81±0.11. On comparison of AUC for predicting significant FFR, SFR (AUC =0.76) had the highest diagnostic accuracy compared to PR (AUC =0.75), % DS (AUC =0.73), TR (AUC =0.69), MLD (AUC =0.71) and DS >50% (AUC =0.64). Using a retrospectively determined optimal cut-off value of 3.51, the sensitivity of stenotic-flow-reserve was modest at 56% with good specificity of 81%. DS >50% had a sensitivity of 47% and specificity of 82% in predicting significant FFR. There was incremental predictive value when SFR was added to DS >50% on integrated discrimination improvement index (IDI =0.103, P<0.001) and net reclassification index (NRI =0.72, P<0.001). SFR has modest diagnostic accuracy for predicting significant FFR but adds incremental predictive value to DS >50% for predicting significant FFR.

Visual-Functional Mismatch Between Coronary Angiography, Fractional Flow Reserve, and Quantitative Coronary Angiography.

Anatomical and functional mismatches are not uncommon in the assessment of coronary lesions. The aim of this study was to identify clinical and lesion-specific factors affecting angiographic, anatomical, and functional mismatch in intermediate coronary lesions. In patients who underwent coronary angiography for clinical reasons, fractional flow reserve (FFR), and quantitative coronary angiography (QCA) analyses for intermediate stenotic lesions were performed simultaneously. Mismatches between the measured values were analyzed. A total of 95 intermediate lesions were assessed simultaneously by visual angiography, FFR, and QCA. The visual-FFR mismatch was found in 40% of the lesions while reverse visual-FFR mismatch was determined in nearly 14% of the lesions. Mismatch and reverse mismatch between FFR and QCA parameters were observed in 10 and 23% of the lesions. FFR value was significant in 32% of the lesions while visually significant stenosis was shown in 61% of the lesions. Among the visual-FFR reverse mismatch group, the prevalence of culprit lesions within the left anterior descending (LAD) was significantly higher than other vessels (p value < 0.02). There were high frequencies of angiographic, QCA, and functional mismatches in analyses of intermediate coronary lesions. LAD lesions showed the highest mismatch. Angiographic or QCA estimation of lesion severity has consistently resulted in inappropriate stenting of functionally nonsignificant lesions or undertreatment of significant lesions based on FFR.

Inter-core lab variability in analyzing quantitative coronary angiography for bifurcation lesions: a post-hoc analysis of a randomized trial.

This study sought to evaluate inter-core lab variability in quantitative coronary angiography (QCA) analysis of bifurcation lesions. QCA of bifurcation lesions is challenging. To date there are no data available on the inter-core lab variability of bifurcation QCA analysis. The randomized Tryton IDE (Tryton Pivotal IDE Coronary Bifurcation Trial) compared the Tryton Side Branch Stent (Tryton Medical, Durham, North Carolina) with balloon angioplasty as side branch treatment. QCA was performed in an angiographic subcohort (n = 326) at 9-month follow-up. Inter-core lab variability of QCA analysis between the Cardiovascular Research Foundation and the Cardialysis core labs was evaluated before and after alignment of the used QCA methodology using angiographic data derived from this angiographic follow-up cohort. In the original analysis, before alignment of QCA methodology, the mean difference between the core labs (bias) was large for all QCA parameters with wide 95% limits of agreement (1.96 × SD of the bias), indicating marked variability. The bias of the key angiographic endpoint of the Tryton trial, in-segment percentage diameter stenosis (%DS) of the side branch, was 5.5% (95% limits of agreement: -26.7% to 37.8%). After reanalysis, the bias of the in-segment %DS of the side branch reduced to 1.8% (95% limits of agreement: -16.7% to 20.4%). Importantly, after alignment of the 2 core labs, there was no longer a difference between both treatment groups (%DS of the side branch: treatment group A vs. group B: 34.4 ± 19.4% vs. 32.4 ± 16.1%, p = 0.340). Originally, a marked inter-core lab variability of bifurcation QCA analysis was found. After alignment of methodology, inter-core lab variability decreased considerably and impacted angiographic trial results. This latter finding emphasizes the importance of using the same methodology among different core labs worldwide. (Tryton Pivotal Prospective, Single Blind, Randomized Controlled Study to Evaluate the Safety & Effectiveness of the Tryton Side Branch Stent Used With DES in Treatment of de Novo Bifurcation Lesions in the Main Branch & Side Branch in Native Coronaries [TRYTON]; NCT01258972).

CORRELATION BETWEEN FRACTIONAL FLOW RESERVE AND QUANTITATIVE CORONARY ANGIOGRAPHY PARAMETERS IN INTERMEDIATE CORONARY ARTERY STENOSIS

ObjectivesTo clarify the relationship between quantitative coronary angiography (QCA) parameters and fractional flow reserve (FFR) for screening out ideal angiographic parameters to predict myocardial ischaemia.MethodsThe study included 121 lesions with...

Two-Year Clinical, Angiographic, and Intravascular Ultrasound Follow-Up of the XIENCE V Everolimus-Eluting Stent in the Treatment of Patients With De Novo Native Coronary Artery Lesions: The SPIRIT II Trial

Two-Year Clinical, Angiographic, and Intravascular Ultrasound Follow-Up of the XIENCE V Everolimus-Eluting Stent in the Treatment of Patients With De Novo Native Coronary Artery Lesions: The SPIRIT II Trial

Randomized Comparison of the Nobori Biolimus A9-Eluting Coronary Stent With the Taxus Liberté Paclitaxel-Eluting Coronary Stent in Patients With Stenosis in Native Coronary Arteries

The newly developed Nobori coronary stent coated with a bioresorbable polymer, polylactic acid, and the antiproliferative agent Biolimus A9 has the potential to reduce restenosis by suppressing neointima formation. We conducted a randomized (2:1), controlled trial comparing the Biolimus A9-eluting stent Nobori and the paclitaxel-eluting stent Taxus Liberté, in 243 patients (153 Nobori and 90 Taxus) at 29 centers in Europe, Asia, and Australia. Patients with previously untreated lesions in up to 2 native coronary arteries were considered for enrollment. The primary end point was in-stent late loss at 9 months, whereas secondary end points included other quantitative coronary angiography parameters, such as in-segment late loss and the rate of restenosis as well as key intravascular ultrasound parameters. Clinical secondary end points were stent thrombosis and composite of major adverse cardiac events comprising death, myocardial infarction, and target vessel revascularization. At 9 months, the in-stent late loss was significantly lower in the Nobori group compared with the Taxus group (0.11+/-0.30 mm versus 0.32+/-0.50 mm) reaching both the primary hypothesis of noninferiority of Nobori stent versus Taxus Liberté stent (P<0.001) and the secondary hypothesis of superiority (P=0.001). This finding was confirmed by a significant reduction in binary restenosis from 6.2% in Taxus to 0.7% in Nobori (P=0.02) and neointimal volume obstruction, detected by intravascular ultrasound, from 5.5+/-7.2% in Taxus to 1.8+/-5.2% in Nobori (P=0.01). The major adverse cardiac events rate was 4.6% in the Nobori and 5.6% in the Taxus cohort of patients. The stent thrombosis rate was 0% in the Nobori arm and 4.4% in the Taxus arm. The NOBORI 1 clinical trial confirmed its primary hypothesis--noninferiority of the Nobori Biolimus A9-eluting stent versus the Taxus Liberté stent in reducing neointimal proliferation. Both stents showed a low major adverse cardiac events rate in the studied population.

Correlation between quantitative angiographic and intravascular ultrasound parameters in patients treated with sirolimus analogous-eluting stents

Despite the undeniable contribution of intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA) to assess drug-eluting stent (DES) effectiveness, the way these image modalities correlate to each other and to target-lesion revascularization (TLR) after PCI, is yet to be established. Thus we sought to evaluate whether there is an acceptable correlation between QCA and IVUS after DES implantation. We analyzed 204 pts treated with DES: Zotarolimus- (126), Sirolimus- (57), and Biolimus (31) with baseline and follow-up QCA and IVUS. The correlation between QCA lumen loss (LL) and intimal hyperplasia (IH) volume obstruction by IVUS was assessed by multiple regression analysis. Two QCA parameters (in-segment diameter stenosis and in-segment LL) and one IVUS variable (in-stent volume of IH) were evaluated as quantitative surrogates of 6 month TLR. The receiver operating characteristic method with c-statistics was used to assess the ability of each surrogate endpoint to predict TLR. QCA LL correlated positively with IVUS IH volume of obstruction (r = 0.69; CI95% 0.61-0.75: P < 0.0001), independent of DES type. The 2 QCA parameters were superior to the IVUS parameter as surrogates for TLR. Of note, QCA LL (c = 0.99) correlated best with TLR, even better than percent DS. In the DES era there is a good correlation between QCA measured LL and IVUS IH volume and therefore can be used as a surrogate of DES efficacy.

Relationship Between Biomarkers of Oxidized Low-Density Lipoprotein, Statin Therapy, Quantitative Coronary Angiography, and Atheroma Volume: Observations From the REVERSAL (Reversal of Atherosclerosis with Aggressive Lipid Lowering) Study

This study was designed to test the hypothesis that circulating biomarkers of oxidized low-density lipoprotein (OxLDL) are affected by statin therapy and predict changes in atheroma volume. Oxidative stress is thought to play an important role in atherogenesis but the relationship between OxLDL, statin therapy, and atheroma volume in humans is not known. In a subgroup of 214 patients from the REVERSAL (Reversal of Atherosclerosis with Aggressive Lipid Lowering) trial, oxidized phospholipids (OxPL) and malondialdehyde (MDA) epitopes per apolipoprotein B-100 (apoB), immunoglobin (Ig) G and IgM apoB immune complexes, and OxLDL autoantibodies were measured at baseline and after 18 months of treatment with atorvastatin or pravastatin. Relationships between changes of OxLDL biomarkers and quantitative coronary angiography (QCA), total atheroma volume, and percentage atheroma volume were analyzed. There were no differences in QCA parameters or atheroma volume in the 2 groups at baseline. Compared with baseline values, OxPL/apoB and MDA/apoB, and lipoprotein (a) levels increased 21% to 48% (p < 0.001 for all) in response to atorvastatin and 17% to 39% (p < 0.001 for all) in response to pravastatin. In contrast, IgG apoB immune complexes, IgM apoB immune complexes, and IgM OxLDL autoantibodies were significantly reduced by both atorvastatin and pravastatin (p value range 0.003 to <0.001). There were no significant differences between the atorvastatin and pravastatin groups. In the entire cohort, there were no correlations between changes in any OxLDL biomarkers and changes in QCA parameters or atheroma volume. Statin therapy results in significant increases in OxPL/apoB, MDA/apoB, and lipoprotein (a) levels and decreases in apoB immune complexes and OxLDL autoantibodies. However, these measures did not correlate with changes in QCA parameters or atheroma volume.

Meta-Analysis of Angiographic Versus Intravascular Ultrasound Parameters of Drug-Eluting Stent Efficacy (from TAXUS IV, V, and VI)

Both quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) are currently used to assess in-stent restenosis. This study aimed to use standardized imaging and clinical follow-up to compare QCA parameters with several IVUS parameters to evaluate their strengths and weaknesses for detecting in-stent restenosis in a drug-eluting stent population. A subset of patients from the TAXUS IV, V, and VI studies was evaluated. The subset, which included 216 TAXUS-treated patients and 191 bare-metal stent-treated patients, had complete IVUS and QCA performed at baseline and follow-up. As expected, all QCA and IVUS parameters were consistent with less intimal hyperplasia in TAXUS patients than controls. The overall incidence of QCA binary restenosis was 14.0%, which was 9.3% in TAXUS-treated patients and 19% in bare-metal stent-treated patients (p = 0.0008). Regression analysis showed that QCA late lumen loss and percentage of diameter stenosis correlated only moderately with the various IVUS measures of neointimal hyperplasia for the combined group of patients (TAXUS + bare-metal stent), as well as for the TAXUS-treated and bare-metal stent-treated patients separately. However, in general, correlations within the control (bare-metal stent) group tended to be stronger than within the TAXUS group. The strongest correlation was between QCA percentage of diameter stenosis and IVUS percentage of intimal hyperplasia in the overall group and the control group. The strongest IVUS predictor of QCA binary restenosis at 9 months was maximum percentage of intimal hyperplasia, with an overall C = 0.91 and p <0.001. In conclusion, the QCA and IVUS parameters used to evaluate drug-eluting stent efficacy showed a moderate correlation with IVUS percentage of intimal hyperplasia, reliably predicting QCA binary in-stent restenosis.

Antihypertensive therapy and regression of coronary artery disease: Insights from the Comparison of Amlodipine versus Enalapril to Limit Occurrences of Thrombosis (CAMELOT) and Norvasc for Regression of Manifest Atherosclerotic Lesions by Intravascular Sonographic Evaluation (NORMALISE) trials

In patients with coronary artery disease (CAD), therapies designed to prevent clinical events are not always associated with significant reduction in coronary obstruction, as measured by quantitative coronary angiography. We set out to explore the relationship between quantitative coronary angiography parameters, baseline characteristics, and clinical events in a large trial of CAD regression with antihypertensive agents. Patients randomized to amlodipine, enalapril, or placebo in the CAMELOT trial were followed for 24 months for major ischemic events. Among 431 patients participating in the angiographic and intravascular ultrasound substudy NORMALISE, 298 (99 amlodipine, 96 enalapril, and 103 placebo) had complete angiographic and intravascular ultrasound data. The patients did not differ significantly with respect to baseline characteristics (except for diabetes) or extent of CAD. After 24 months, the change in minimal lumen diameter (MLD) was -0.02 +/- 0.13 for amlodipine, -0.03 +/- 0.12 for enalapril, and -0.03 +/- 0.17 mm for placebo (P = .40). Major ischemic events occurred in 20.2%, 24%, and 25.2%, respectively (P = .68). There was no significant correlation between change in MLD and age, sex, statin therapy, or systolic blood pressure at baseline. The change in MLD did not differ in patients with and without cardiovascular events, regardless of treatment assignment (P = .54). Only the extent of CAD was independently predictive of ischemic events. As compared to placebo, amlodipine treatment resulted in fewer ischemic events after 24 months of therapy, but the clinical benefit was not associated with a commensurate improvement in arterial lumen dimensions.

A Comparison of the Intravascular Ultrasound Findings before and after Coronary Stent Implantation in Patients with Small Vessel Disease(2.5-2.75 mm) by Quantitative Coronary Angiography

Background and Objectives:From a clinical standpoint, coronary artery disease in blood vessels measuring 2.5 mm to 2.75 mm, as accessed by quantitative coronary angiography (QCA), has been classified as a small vessel disease, and it is treated with percutaneous coronary intervention (PCI). The aim of this study was to evaluate the discrepancy of vessel size between intravascular ultrasound (IVUS) and QCA, and its late outcome before and after stent implantation in patients with small coronary artery disease (2.5-2.75 mm). Subjects and Methods:We enrolled 135 patients having 143 lesions who underwent IVUS-guided PCI. Twenty-three patients (26 lesions) were in the small vessel (SV, ≤2.75 mm) group and 112 patients (128 lesions) were in the large vessel (LV, >2.75 mm) group. We evaluated the IVUS and QCA parameters’ association with mortality, acute myocardial infarction (AMI) and target vessel revascularization (TVR) at the 1 year follow-up. Results:On QCA, the pre-interventional reference vessel diameters and post-stent minimal lumen diameters in the SV group were smaller than those in the LV group. The discrepancy of vessel size between IVUS and QCA at the reference site was larger in the SV group than that in the LV group (1.44 mm vs. 0.92 mm, respectively p<0.05). This discrepancy was significantly associated with the plaque area in both groups (p<0.001). Despite of having larger stents implanted in the SV group than the LV group, there was no difference in mortality, AMI and TVR after 1 year between the 2 groups. Conclusion:A coronary artery disease measuring 2.5 mm to 2.75 mm by QCA revealed large vessels with a high percentage of plaque. The bigger stent implantation using IVUS did not show more complications after PCI and there were favorable clinical outcomes at 1 year for patients with this condition. (Korean Circulation J 2005;35:123-130)

178 Quantitative evaluation of regional myocardial perfusion during dipyridamole stress by real-time myocardial contrast echocardiography in patients with and without coronary artery disease

178 Quantitative evaluation of regional myocardial perfusion during dipyridamole stress by real-time myocardial contrast echocardiography in patients with and without coronary artery disease

Reproducibility of quantitative coronary analysis, Assessment of variability due to frame selection, different observers, and different cinefilmless laboratories.

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 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, as well 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.