Intravascular Ultrasound Minimal Lumen Area Research Articles

Computed tomography coronary angiography assessment of left main coronary artery stenosis severity

BackgroundAngiographic assessment of left main coronary artery (LMCA) stenosis severity can be unreliable. In cases of ambiguity, intravascular ultrasound (IVUS) can be utilised with a minimal lumen area (MLA) of ≥6 ​mm2 an accepted threshold for safe deferral of revascularization. We sought to assess whether quantitative computer tomography coronary angiography (CTCA) measures could assist clinicians making LMCA revascularization decisions when compared with IVUS as gold standard. MethodsConsecutive patients undergoing IVUS assessment of angiographically intermediate LMCA stenosis were included. All patients had undergone 320-slice CTCA <90 days prior to IVUS imaging. Offline quantitative assessment of IVUS- and CT-derived measures were undertaken with the cohort divided into those with significant (s-LMCA) versus non-significant (ns-LMCA) disease using the accepted IVUS threshold. ResultsFifty-eight patients were included, with no difference in mean age (61.5 ​± ​12.2 vs. 59.7 ​± ​11.9 years, p ​= ​0.57), diabetic status (24.2% vs 16.0%, p ​= ​0.44) or other baseline demographics between groups. Patients with ns-LMCA had larger CT luminal area (8.64 ​± ​3.91 vs. 5.41 ​± ​1.54 ​mm2, p ​< ​0.001), larger minimal lumen diameter (MLD) (3.25 ​± ​0.74 vs. 2.56 ​± ​0.38 ​mm, p ​< ​0.001) and lower area stenosis (45.74 ​± ​18.10 vs. 60.93 ​± ​14.68%, p ​= ​0.001). There was a significant positive correlation between CTCA and IVUS MLA (r ​= ​0.68, p ​< ​0.001) and MLD (r ​= ​0.67, p ​< ​0.001). ROC analysis demonstrated CTCA MLA cut-off <8.29 ​mm2 provides the greatest negative predictive value and sensitivity in predicting the presence of significant LMCA disease. ConclusionCTCA derived MLA and MLD have a strong correlation with IVUS. A CTCA derived MLA cut-off <8.29 ​mm2 showed greatest clinical utility for predicting the need for further assessment, based on IVUS gold standard.

Impact of Nonobstructive Left Main Coronary Artery Atherosclerosis on Long-Term Mortality

BackgroundAlthough the presence of severe stenosis in the left main coronary artery (LMCA) is a well-established predictor of mortality, whether this extends to nonobstructive atherosclerosis in the LMCA is unknown. ObjectivesThe aim of this study was to evaluate the association between LMCA disease by intravascular ultrasound (IVUS) and long-term mortality. MethodsBetween 2005 and 2013, 3,239 patients with LMCA IVUS imaging without LMCA revascularization (either before angiography or scheduled based on index angiography or IVUS) were included. The primary and secondary endpoints were all-cause and cardiac mortality at a minimum of 5 years obtained from the National Death Index. ResultsThe IVUS-measured LMCA minimum lumen area (MLA) and plaque burden were 13.1 ± 5.0 mm2 and 41.7% ± 15.6%, respectively. The median follow-up was 8.2 years. The Kaplan-Meier estimated 12-year all-cause and cardiac death rates were 37.5% and 17.0%, respectively. Greater plaque burden (unadjusted HR per 10%: 1.17; 95% CI: 1.12-1.22; P < 0.0001) and smaller IVUS MLA (unadjusted HR per 1 mm2: 0.98; 95% CI: 0.96-0.99; P = 0.0008) were associated with all-cause death. After adjusting for clinical, angiographic, and IVUS factors, plaque burden (adjusted HR per 10%: 1.12; 95% CI: 1.04-1.21; P = 0.003) but not MLA (adjusted HR per 1 mm2: 1.02; 95% CI: 0.99-1.04; P = 0.18) was associated with long-term all-cause death. These findings were also consistent for long-term cardiac mortality. ConclusionsIn the present large-scale study with a 12-year follow-up, increasing LMCA plaque burden was associated with long-term all-cause and cardiac mortality in patients not undergoing LMCA revascularization, even when the lumen area was preserved.

Comprehensive non-invasive and invasive functional assessment of anomalous coronary arteries with anatomical high-risk features

Abstract Background Anomalous aortic origin of a coronary artery (AAOCA) is a rare congenital disease associated with an increased risk of myocardial ischemia. In AAOCA, the occurrence of ischemia is based on the extent of a fixed and a dynamic component, each attributed to different anatomical high-risk features (i.e., acute take-off angle, slit-like ostium, proximal narrowing, elliptic vessel shape and intramural course). Coronary computed tomography angiography (CCTA) is the primary non-invasive imaging method to depict the presence and quantitatively assess anatomical high-risk features while invasive physiologic evaluation under maximal dobutamine-volume challenge is the gold standard to unravel the hemodynamic relevance of AAOCA. Methods We included all consecutive AAOCA patients with anatomical high-risk features from our prospective, open-label registry. The objective is to quantify anatomical high-risk features in the CCTA and to measure hemodynamic relevance using invasive fractional flow reserve with maximal dobutamine-volume challenge (gradually increasing dose of dobutamine max. 40 μg/kg per body weight/min, max. 3000 mL ringer lactate and max. 1mg atropine). Pathological invasive FFR was defined as FFR Dobutamine&amp;lt;0.80. Additionally, CCTA-data were processed to assess computational fluid dynamics (CT FFR) and intravascular ultrasound (IVUS) was used to determine minimal lumen area (MLA) during baseline and maximal stress conditions. Results A total of 11 patients were included between 05/19 and 11/2020. Mean age was 59±13 years (range: 40–79), 10 patients showed a right-AAOCA and one patient showed a single right coronary artery. All patients had either one (i.e., in 1 patient) or more than one anatomical-high risk features (i.e., in 10 patients). Mean invasive FFR Dobutamine was 0.88±0.07 with n=2 (18%) being pathological. Mean non-invasive CT FFR was 0.89±0.04 (FFR&amp;lt;0.80; n=0), mean invasive FFR Adenosine was 0.92±0.06 (FFR&amp;lt;0.80; n=1; 9%). There was a significant decrease in IVUS MLA between rest (7.93±2.79mm2) and under dobutamine-volume challenge (6.57±3.20mm2, p=0.008). Mean percentage of MLA reduction was 19±18%. Conclusion Our preliminary results provide evidence that relevant myocardial ischemia seems to be often absent in a middle-aged population with AAOCA and anatomical high-risk features. However, in a minority of cases hemodynamic relevance could be depicted, especially when stressing with dobutamine-volume challenge. The presence of a dynamic component in AAOCA is represented by the reduced minimal lumen area under stress conditions. Comprehensive diagnostic evaluation should be performed to prevent unnecessary guideline recommended open-heart surgery in a middle-aged population with AAOCA. Funding Acknowledgement Type of funding sources: None.

Correlation of Intravascular Ultrasound and Instantaneous Wave-Free Ratio in Patients With Intermediate Left Main Coronary Artery Disease.

There is great degree of interobserver variability in the visual angiographic assessment of left main coronary disease (LMCD). Fractional flow reserve and intravascular ultrasound are often used in this setting. The use of instantaneous wave-free ratio (iFR) for evaluation of LMCD has not been well studied. The aim of this study is to evaluate the use of iFR in the assessment of angiographically intermediate LMCD. This is an international multicenter retrospective observational study of patients who underwent both iFR and intravascular ultrasound evaluation for angiographically intermediate LMCD. An independent core laboratory performed blinded off-line analysis of all intravascular ultrasound data. A minimum lumen area of 6 mm2 was used as the cutoff for significant disease. One hundred twenty-five patients (mean age, 68.4±9.5 years, 84.8% male) were included in this analysis. Receiver operating curve analysis showed that an iFR of ≤0.89 identified minimum lumen area <6 mm2 with an area under the curve of 0.77 (77% sensitivity, 66% specificity; P<0.0001). Among the 69 patients without ostial left anterior descending artery or left circumflex artery disease, receiver operating curve analysis showed that an iFR of ≤0.89 identified minimum lumen area <6 mm2 with an area under the curve of 0.84 (70% sensitivity, 84% specificity; P<0.0001). The correlation was not significantly different when the body surface area was considered. In this study, in patients with intermediate LMCD, iFR of ≤0.89 correlates with intravascular ultrasound minimum lumen area <6 mm2 regardless of body surface area. The current study supports the use of iFR for the evaluation of intermediate LMCD.

Comparison of three-dimensional quantitative coronary angiography and intravascular ultrasound for detecting functionally significant coronary lesions.

Three-dimensional quantitative coronary angiography (3D-QCA) can provide more accurate measurement of true vessel size and may be comparable to intravascular ultrasound (IVUS) in identifying functionally significant coronary stenosis, as determined by fractional flow reserve (FFR). This study aimed to evaluate the diagnostic accuracy of 3D-QCA for predicting FFR <0.8. We assessed 175 lesions in 175 patients by FFR, IVUS, and 3D-QCA. Correlations between 3D-QCA values, IVUS values, and FFR values were analyzed. Receiver operating characteristic (ROC) curves were used to evaluate diagnostic accuracy of 3D-QCA for predicting FFR <0.8 and to determine the appropriate cut-off value. Upon evaluating 3D-QCA values, minimum lumen area (MLA) correlated with FFR value (r=0.48, P<0.001). Considering IVUS values, MLA correlated with FFR value (r=0.43, P<0.001). Also, 3D-QCA MLA was well correlated with IVUS MLA (r=0.61, P<0.001). The area under the ROC curve (AUC) for 3D-QCA MLA was 0.77, and the best cut-off value was 2.37 (sensitivity: 73%, specificity: 71%). The AUC for IVUS MLA was 0.73, and the best cut-off value was 3.01 (sensitivity: 71%, specificity: 65%). There was no significant difference in AUC for 3D-MLA and IVUS-MLA (P=0.27). 3D-QCA is not inferior to IVUS for functional assessment of intermediate coronary lesions. We can consider 3D-QCA as a suitable substitute for IVUS or FFR in determining coronary intervention.

Gravedad de la enfermedad coronaria definida por ultrasonido intravascular o tomografía de coherencia óptica y su relación con los índices fisiológicos

Introduction and objectivesFractional flow reserve or instantaneous wave-free ratio has become a standard criterion for revascularization. We sought to evaluate the association between intravascular ultrasound (IVUS) or optical coherence tomography (OCT)-derived quantitative plaque characteristics and the severity of physiologic stenosis. MethodsA total of 365 stenoses from 330 patients were evaluated. The association between IVUS or OCT-derived parameters and resting physiologic indices (instantaneous wave-free ratio, resting full-cycle ratio, and diastolic pressure ratio) and fractional flow reserve were explored. ResultsAmong the total number of lesions, 50.7% and 58.1% showed an instantaneous wave-free ratio ≤ 0.89 and fractional flow reserve ≤ 0.80, respectively. IVUS or OCT-derived parameters showed significant correlations with resting physiologic indices (P values <.005). The best cutoff values of IVUS minimum lumen area (MLA), plaque burden, OCT-MLA, and OCT-area stenosis to predict functional significance were the same (IVUS-MLA: 3.4 mm2, plaque burden: 72.0%, OCT-MLA: 2.0 mm2, OCT-area stenosis: 68.0%) for all resting physiologic indices (instantaneous wave-free ratio, resting full-cycle ratio, and diastolic pressure ratio). The best cutoff values for fractional flow reserve were an IVUS-MLA of 3.8 mm2, plaque burden of 70.0%, OCT-MLA of 2.3 mm2, and OCT-area stenosis of 65.0%. Regardless of IVUS or OCT-derived parameters, the overall diagnostic accuracies of the parameters were lower than 70% and discrimination indices were less than 0.75 for resting physiologic indices or fractional flow reserve. ConclusionsThe resting physiologic indices showed an identical relationship with IVUS or OCT-defined quantitative plaque characteristics. The diagnostic accuracy and discrimination ability of anatomical parameters were modest in predicting functional significance defined by resting and hyperemic invasive physiologic indices.This trial is registered at ClinicalTrials.gov (Identifier: NCT03795714).

309 Computed Tomography Coronary Angiography for the Assessment of Left Main Coronary Artery Stenosis

Angiographic assessment of left main coronary artery (LMCA) stenosis is challenging. When uncertainty exists, intravascular ultrasound (IVUS) minimal lumen area (MLA) ≥6 mm2 is used as safe threshold for deferral of revascularization. With emergence of Computed Tomography Coronary Angiography (CTCA) as a first-line investigation, we sought to assess which quantitative CT-measure best compared with current IVUS standards. Patients who underwent both IVUS and CTCA assessment of angiographically intermediate LMCA stenosis (n=48) were included. All CTCA were performed <90 days prior to IVUS. The cohort was divided into those with significant (S-LMCA) versus non-significant (NS-LMCA) disease, using IVUS ≥6 vs <6 mm2. Mean age (60.3±12.4 vs 59.9±11.9yrs, p=0.91) and % male (57.7% vs 54.6%, p=0.83) were similar between groups. Mean time from CTCA to IVUS assessment was 17.4±19.8 days, with mean QCA stenosis severity of 46.0±18.6%. On CTCA, patients with NS-LMCA had significantly higher luminal area (8.3±3.8 vs 5.2±1.6 mm2, p=0.005), minimal lumen diameter (MLD) (3.2±0.7 vs 2.5±0.4 mm, p<0.001), with similar luminal volumes (99.9±50.5 vs 113.5±73.9 mm3, p=0.47). There was a significant positive correlation between CTCA and IVUS MLA (r=0.77, p <0.001) and MLD (r=0.73, p<0.001). ROC analysis demonstrated CTCA MLA <8.29 mm2 had the best diagnostic accuracy for predicting IVUS MLA <6 mm2 (area under the curve=0.76, sensitivity=100%, specificity=54% p=0.002). CTCA luminal measures correlate well with IVUS within the LMCA. These results suggest that CTCA measures could potentially be used to safely defer revascularisation for LMCA disease.

Intravascular ultrasound or optical coherence tomography-defined anatomic severity and hemodynamic severity assessed by coronary physiologic indices.

Fractional flow reserve or instantaneous wave-free ratio has become a standard criterion for revascularization. We sought to evaluate the association between intravascular ultrasound (IVUS) or optical coherence tomography (OCT)-derived quantitative plaque characteristics and the severity of physiologic stenosis. A total of 365 stenoses from 330 patients were evaluated. The association between IVUS or OCT-derived parameters and resting physiologic indices (instantaneous wave-free ratio, resting full-cycle ratio, and diastolic pressure ratio) and fractional flow reserve were explored. Among the total number of lesions, 50.7% and 58.1% showed an instantaneous wave-free ratio ≤ 0.89 and fractional flow reserve ≤ 0.80, respectively. IVUS or OCT-derived parameters showed significant correlations with resting physiologic indices (P values <.005). The best cutoff values of IVUS minimum lumen area (MLA), plaque burden, OCT-MLA, and OCT-area stenosis to predict functional significance were the same (IVUS-MLA: 3.4 mm2, plaque burden: 72.0%, OCT-MLA: 2.0 mm2, OCT-area stenosis: 68.0%) for all resting physiologic indices (instantaneous wave-free ratio, resting full-cycle ratio, and diastolic pressure ratio). The best cutoff values for fractional flow reserve were an IVUS-MLA of 3.8 mm2, plaque burden of 70.0%, OCT-MLA of 2.3 mm2, and OCT-area stenosis of 65.0%. Regardless of IVUS or OCT-derived parameters, the overall diagnostic accuracies of the parameters were lower than 70% and discrimination indices were less than 0.75 for resting physiologic indices or fractional flow reserve. The resting physiologic indices showed an identical relationship with IVUS or OCT-defined quantitative plaque characteristics. The diagnostic accuracy and discrimination ability of anatomical parameters were modest in predicting functional significance defined by resting and hyperemic invasive physiologic indices. This trial is registered at ClinicalTrials.gov (Identifier: NCT03795714).

INTRAVASCULAR ULTRASOUND MECHANISMS OF IN-STENT RESTENOSIS IN SAPHENOUS VEIN GRAFT LESIONS

The mechanisms of saphenous vein graft (SVG) in-stent restenosis (ISR) have not been well described. Intravascular ultrasound (IVUS) was used to evaluate 46 SVG ISR lesions (angiographic diameter stenosis >50% or IVUS minimal lumen area <4mm2) in 45 pts. Neoatherosclerosis was defined as either

Patterns of Coronary Calcification and Their Impact on the Diagnostic Accuracy of Computed Tomography Coronary Angiography.

Despite coronary calcifications being a major factor affecting the diagnostic accuracy of coronary computed tomography angiography (CTA), there is a lack of established criteria for categorizing calcifications. We aimed to evaluate patterns of coronary calcification based on quantitative radiodensity and size parameters to provide coronary calcium categories and assess their impact on the accuracy of coronary CTA. We analyzed length, maximum thickness, volume, mean density, and maximum density of coronary calcium and divided each of these parameters into tertiles. Subsequently, we summarized the tertiles for each individual calcification and divided them into 3 equal groups of: mild, moderate, and severe calcification. The accuracy of coronary CTA was defined as the difference between the measurements obtained on coronary CTA versus the reference of intravascular ultrasound (IVUS). We evaluated 252 coronary calcifications within 97 arteries of 60 patients. There was an expected increase in size and density values for mild versus moderate versus severe calcifications, but there was no difference in IVUS measured minimum lumen area among the 3 groups. Of note, coronary CTA significantly underestimated IVUS minimum lumen area measurement by 1.2 ± 1.6 mm (14.6 ± 23.1%, P < 0.001) for severe calcifications and by 0.5 ± 2.0 mm (3.7 ± 32.1%, P = 0.021) for moderate calcifications. Within mild calcifications, the difference was not significant. Based on their dimensional and radiodensity characteristics, our analysis revealed patterns of individual coronary artery calcifications that affected the accuracy of coronary CTA measurements; coronary CTA inaccuracy was associated with the presence of moderate or severe calcifications, but not mild calcifications.

Predictors of Clinical Outcome in Patients with Angiographically Intermediate Lesions with Minimum Lumen Area Less than 4 mm2 Using Intravascular Ultrasound in Non-Proximal Epicardial Coronary Artery.

We investigated predictors of major adverse cardiac events (MACE) with two years after medical treatment for lesions with angiographically intermediate lesions with intravascular ultrasound (IVUS) minimum lumen area (MLA) <4 mm2 in non-proximal epicardial coronary artery. We retrospectively enrolled 104 patients (57 males, 62±10 years) with angiographically intermediate lesions (diameter stenosis 30–70%) with IVUS MLA <4 mm2 in the non-proximal epicardial coronary artery with a reference lumen diameter between 2.25 and 3.0 mm. We evaluated the incidences of major adverse cardiovascular events (MACE including death, myocardial infarction, target lesion and target vessel revascularizations, and cerebrovascular accident) two years after medical therapy. During the two-year follow-up, 15 MACEs (14.4%) (including 1 death, 2 myocardial infarctions, 10 target vessel revascularizations, and 2 cerebrovascular accidents) occurred. Diabetes mellitus was more prevalent (46.7% vs. 18.0%, p=0.013) and statins were used less frequently in patients with MACE compared with those without MACE (40.0% vs. 71.9%, p=0.015). Independent predictors of MACEs with two years included diabetes mellitus (odds ratio [OR]=3.41; 95% CI=1.43–8.39, p=0.020) and non-statin therapy (OR=3.11; 95% CI=1.14–6.50, p=0.027). Long-term event rates are relatively low with only medical therapy without any intervention, so the cut-off of IVUS MLA 4 mm2 might be too large to be applied for defining significant stenosis. The predictors of long-term MACE were diabetes mellitus and statin therapy in patients with angiographically intermediate lesions in non-proximal epicardial coronary artery.

Comparison of 3-dimensional and 2-dimensional quantitative coronary angiography and intravascular ultrasound for functional assessment of coronary lesions

BackgroundThree-dimensional quantitative coronary angiography (3D-QCA) reportedly allows more accurate delineation of true vessel geometry when compared with standard two-dimensional (2D) QCA and has been validated by intravascular ultrasound (IVUS). This study sought to compare diagnostic efficiency of 2D- and 3D-QCA, and IVUS in identifying hemodynamically significant coronary stenoses as determined by fractional flow reserve (FFR). MethodsForty-two lesions in 40 patients were assessed by FFR, IVUS, and 2D- and 3D-QCA. Correlations between FFR values and anatomical parameters obtained by 2D- and 3D-QCA and IVUS were analyzed. The receiver operating characteristic (ROC) curves were used to compare the diagnostic accuracy of the parameters for predicting FFR≤0.80. ResultsMean FFR value was 0.75±0.13. FFR≤0.80 was observed in 28 lesions (67%). Of IVUS measurements, minimum lumen area (MLA) well correlated with FFR values (r=0.71, p<0.001). Of 3D- and 2D-QCA measurements, minimum lumen diameter (MLD) correlated best with FFR values (r=0.79, p<0.01; r=0.68, p<0.01, respectively), followed by MLA (r=0.76, p<0.01; r=0.67, p<0.01, respectively). The area under the ROC curve for 3D-QCA MLD was greater than those for 2D-QCA MLD (p=0.03) and 2D-QCA MLA (p=0.03). On the other hand, the AUC for 3D-QCA MLD, 3D-QCA MLA, and IVUS MLA were not significantly different. Conclusions3D-QCA is more useful than 2D-QCA and possibly comparable to IVUS in the assessment of functional stenosis severity. When FFR is not available, 3D-QCA MLA and MLD may assist in the assessment of functional severity of intermediate lesions.

Better Diagnosis of Functionally Significant Intermediate Sized Narrowings Using Intravascular Ultrasound-Minimal Lumen Area and Coronary Computed Tomographic Angiography–Based Myocardial Segmentation

Lesion morphology poorly predicts functional significance of intermediate coronary artery stenosis. The aim of this study was to determine whether a coronary artery-based myocardial segmentation method that quantifies subtended myocardium can improve the diagnostic accuracy of intravascular ultrasound (IVUS)-derived parameters for detecting ischemia-producing lesions. Coronary computed tomography angiography, IVUS, and fractional flow reserve (FFR) data were analyzed in 101 non-left main lesions (20% to 80% angiographic stenosis). Using the coronary artery-based myocardial segmentation method, total left ventricular myocardial volume (Vtotal), myocardial volume subtended by the stenotic coronary segment (Vsub), and Vratio (the ratio of the Vsub to the Vtotal) were assessed. Both Vsub >30.7cm(3) and Vratio >25.4% were determinants of FFR ≤0.75 (area under the curve= 0.696 and 0.744). Overall, an IVUS-measured minimum lumen area (IVUS-MLA) ≤2.83mm(2) predicted FFR ≤0.75 with a sensitivity 88% and specificity 73%. Among lesions with IVUS-MLA ≤2.83mm(2) and FFR >0.75, 89% showed Vsub <30.7cm(3). In 50 lesions with Vsub >30.7cm(3), an IVUS-MLA ≤2.85mm(2) predicted FFR ≤0.75 with sensitivity 85%, specificity 92%, positive predictive value 92%, and negative predictive value 85%. Conversely, in 51 lesions with a Vsub ≤30.7cm(3), IVUS-MLA ≤2.67mm(2) showed sensitivity 100%, specificity 69%, positive predictive value 38%, and negative predictive value 100% for predicting FFR ≤0.75. Body surface area, reference lumen diameter, and vessel area had modest correlations with Vsub. In those lesion subsets, IVUS-MLA ≈2.8mm(2) accurately predicted an FFR ≤0.75, whereas the clinical relevance of assessing and treating lesions with a smaller myocardial territory may be limited (ClinicalTrials.gov number NCT1696006).

NEW CUT-OFF VALUE OF IVUS MINIMAL LUMEN AREA (MLA) AND FRACTIONAL FLOW RESERVE (FFR) TO DEFINE THE FUNCTIONAL SIGNIFICANCE OF DENOVO INTERMEDIATE CORONARY STENOSIS

Background: Intravascular Ultrasound (IVUS) is a supportive tool for coronary angiography in evaluating intermediate coronary lesions. However, old cut-off value of 4mm2 of IVUS Minimal Lumen Area (MLA) has been proved very low diagnosic accuracy. Objective: We aimed to assess a new cut-off value of IVUS MLA and its diagnostic performance to predict ischemia, using fractional flow reserve (FFR) as gold standard. Methods: Denovo Intermediate lesions were evaluated with both IVUS and FFR. A total of 32 lesions were enrolled into the study. Results: Thirty two patients, who had denovo intermediate lesions distributing at prox-mid segment of RCA (31.3%), LAD (59.4%) and LCx (6.2%), were enrolled into this study, with average age: 63.97±11.59 (years), male: 71.9% and female: 28.1%, mean diameter stenosis: 50.68% ± 8.83 and mean reference diameter: 2.99 mm ± 0.61mm. IVUS MLA (r = 0.386, p &lt; 0.014) correlated with FFR. The stenotic diameter (r = -0.159, p &lt; 0.192), the length (r = -0.052, p = 0.389) and the plaque volume (r = -0.105, p = 0.284) didn’t well correlate with FFR. Best cut-off value (BCV) of IVUS MLA to define the functional significance (FFR ≤0.8) was 2.55 mm2 (AUC 0.776; 95% CI 0.607-0.946) with sensitivity and specitivity were 66.7% and 88.2% respectively. Conclusion: In this study, an IVUS MLA of 2.55 mm2 was the BCV to define the functional significance of denovo intermediate coronary stenosis. However, when IVUS MLA is used to determine the functional significance, both the lesion diameter and length should be considered. Key words: intermediate lesion, intravascular ultrasound (IVUS), Fractional Flow Reserve (FFR)

Intravascular Ultrasound-Derived Minimal Lumen Area Criteria for Functionally Significant Left Main Coronary Artery Stenosis

ObjectivesThis study sought to evaluate the intravascular ultrasound (IVUS) minimal lumen area (MLA) for functionally significant left main coronary artery (LMCA) stenosis using fractional flow reserve (FFR) as the standard. BackgroundThe evaluation of significant LMCA stenosis remains challenging. MethodsWe identified 112 patients with isolated ostial and shaft intermediate LMCA stenosis (angiographic diameter stenosis of 30% to 80%) who underwent IVUS and FFR measurement. ResultsThe FFR was ≤0.80 in 66 LMCA lesions (59%); these exhibited smaller reference vessels, smaller minimal lumen diameter, greater diameter of stenosis, longer lesion length, smaller MLA, larger plaque burden, and more frequent plaque rupture. The independent factors of an FFR of ≤0.80 were plaque rupture (odds ratio [OR]: 4.47; 95% Confidence Interval (CI): 1.35 to 14.8; p = 0.014); body mass index (OR: 1.19; 95% CI: 1.00 to 1.41; p = 0.05), age (OR: 0.95; 95% CI: 0.90 to 1.00; p = 0.031), and IVUS MLA (OR: 0.37; 95% CI: 0.25 to 0.56; p < 0.001). The optimal IVUS MLA cutoff value for an FFR of ≤0.80 was 4.5 mm2 (77% sensitivity, 82% specificity, 84% positive predictive value, 75% negative predictive value, area under the curve: 0.83, 95% CI: 0.76 to 0.96; p < 0.001) overall and 4.1 to 4.5 mm2 in various subgroups. Adjustment for the body surface area, body mass index, and left ventricular mass did not improve the diagnostic accuracy of the IVUS MLA. ConclusionsIn patients with isolated ostial and shaft intermediate LMCA stenosis, an IVUS-derived MLA of ≤4.5 mm2 is a useful index of an FFR of ≤0.80.

Diagnostic value of coronary CT angiography in comparison with invasive coronary angiography and intravascular ultrasound in patients with intermediate coronary artery stenosis: results from the prospective multicentre FIGURE-OUT (Functional Imaging criteria for GUiding REview of invasive coronary angiOgraphy, intravascular Ultrasound, and coronary computed Tomographic angiography) study

The anatomical criteria for the diagnosis of ischaemia referenced by fractional flow reserve (FFR) from non-invasive coronary computed tomographic angiography (CCTA), invasive coronary angiography (ICA), and intravascular ultrasound (IVUS) have not been evaluated contemporarily in a large-scale study. The aim of this study was to assess the diagnostic value of CCTA compared with ICA and IVUS in patients with intermediate coronary stenosis. CCTA, ICA, IVUS, and FFR were performed in 181 coronary lesions with intermediate severity. Minimal lumen diameter (MLD) and per cent diameter stenosis (%DS) were determined by CCTA and ICA, whereas minimal lumen area (MLA) was determined by CCTA and IVUS. Inducible ischaemia was defined by FFR ≤ 0.80. Diagnostic performances from non-invasive and invasive methods were compared. FFR ≤ 0.80 was observed in 49 (27.1%) lesions. CCTA MLD was smaller than ICA MLD (1.3 ± 0.5 vs. 1.5 ± 0.4 mm, P < 0.001), CCTA %DS was higher than ICA %DS (54.0 ± 14.0 vs. 50.3 ± 12.8%, P < 0.001), and CCTA MLA was smaller than IVUS MLA (2.2 ± 1.2 vs. 3.2 ± 1.2 mm(2), P < 0.001). This trend was consistent irrespective of lesion location, lesion severity, and plaque characteristics. For the determination of ischaemia, diagnostic performance of CCTA %DS was lower than ICA %DS [area under the curve (AUC) 0.657 vs. 0.765, P = 0.04], and that of CCTA MLA was lower than IVUS MLA (AUC 0.712 vs. 0.801, P = 0.03). Anatomical criteria for the diagnosis of ischaemia-producing coronary stenosis differ by non-invasive and invasive methods. Compared with invasive methods, CCTA presents overestimation in assessing lesion severity and lower diagnostic performance in assessing ischaemia.

Optimal Intravascular Ultrasound Criteria for Defining the Functional Significance of Intermediate Coronary Stenosis: An International Multicenter Study

Objective: We aimed to assess the ideal cut-off value of minimal lumen area (MLA) by intravascular ultrasound (IVUS) and its diagnostic performance to predict ischemia, using a large-scale, pooled analysis. Methods: Eleven centers worldwide were invited to provide their clinical, IVUS and fractional flow reserve (FFR) data. A total of 881 lesions were enrolled. Results: Angiographic % diameter stenosis (r = -0.373, p < 0.0001) and IVUS MLA (r = 0.289, p < 0.0001) correlated with FFR. Best cut-off value (BCV) of IVUS MLA to define the functional significance (FFR <0.8) was 2.75 mm² (AUC 0.646, 95% CI 0.609-0.684). When the diagnostic performance of IVUS MLA was tested according to the lesion location, BCV could be found only in lesions in the proximal artery and the mid-left anterior descending artery. Interestingly, Asians (n = 623) and Westerners (n = 258) showed different demographic and lesion characteristics as well as different BCVs to define ischemia. The BCV for the proximal/mid-left anterior descending artery lesions was 2.75 mm² (AUC 0.688, 95% CI 0.635-0.742) in Asians and 3.0 mm² (AUC 0.695, 95% CI 0.605-0.786) in Westerners. Conclusion: In this pooled analysis, an IVUS MLA of 2.75 mm² was the BCV to define the functional significance of intermediate coronary stenosis. However, when IVUS MLA is used to determine the functional significance, both the lesion and patient characteristics should be considered.

Clinical Outcomes in Patients with Intermediate Coronary Stenoses: MINIATURE Investigators (Korea MultIceNter TrIal on Long-Term Clinical Outcome According to the Plaque Burden and Treatment Strategy in Lesions with MinimUm Lumen ARea lEss Than 4 mm(2) Using Intravascular Ultrasound).

Background and ObjectivesWe evaluated the two-year clinical outcomes in patients with angiographically intermediate lesions according to the plaque burden and treatment strategy.Subjects and MethodsWe prospectively enrolled patients with angiographically intermediate lesions (diameter stenosis 30-70%) with an intravascular ultrasound (IVUS) minimum lumen area (MLA) <4 mm2 with 50-70% plaque burden of 16 Korean percutaneous coronary intervention centers. Patients were divided into medical therapy group (n=85) and zotarolimus-eluting stent group (ZES; Resolute) group (n=74). We evaluated the incidences of two-year major adverse cardiovascular events (MACE).ResultsA two-year clinical follow-up was completed in 143 patients and MACE occurred in 12 patients. There were no significant differences in the incidences of death (1.3% vs. 3.0%, p=0.471), target vessel-related non-fatal myocardial infarction (0.0% vs. 0.0%, p=1.000) and target vessel revascularizations (7.8% vs. 4.5%, p=0.425) between medical and ZES groups. Independent predictors of two-year MACE included acute myocardial infarction {odds ratio (OR)=2.87; 95% confidence interval (CI) 1.43-6.12, p=0.014}, diabetes mellitus (OR=2.46; 95% CI 1.24-5.56, p=0.028) and non-statin therapy (OR=2.32; 95% CI 1.18-5.24, p=0.034).ConclusionMedical therapy shows comparable results with ZES, and myocardial infarction, diabetes mellitus and non-statin therapy were associated with the occurrence of two-year MACE in patients with intermediate lesion with IVUS MLA <4 mm2 with 50-70% of plaque burden.

Predictors for Functionally Significant In-Stent Restenosis: An Integrated Analysis Using Coronary Angiography, IVUS, and Myocardial Perfusion Imaging

The aim of this study was to assess the clinical and morphological predictors for functionally significant in-stent restenosis (ISR).Although they have been studied de novo in native coronary artery lesions, the relationships between clinical and morphological characteristics and the hemodynamic significance of ISR are not well understood.In 175 patients with ISR of a single coronary artery (angiographic stenosis >50%), we compared quantitative coronary angiography and intravascular ultrasound (IVUS) with stress myocardial single-photon emission computed tomography (SPECT). A positive SPECT was a reversible perfusion defect in the territory of the ISR artery.Overall, 103 (59%) patients had a positive SPECT. In-segment IVUS minimal lumen area (MLA) was significantly smaller in lesions with positive SPECT compared with negative SPECT (1.7 ± 0.5 mm(2) vs. 2.4 ± 0.8 mm(2), p < 0.001). Stent underexpansion (minimal stent area <5.0 mm(2)) was more common in the positive SPECT group than in the negative SPECT group (52% vs. 32%, p = 0.010). A positive SPECT was seen in 54% (65 of 121) of focal ISR lesions compared with 70% (38 of 54) of multifocal or diffuse ISR lesions as assessed by IVUS (p = 0.039). Independent determinants for a positive SPECT were diabetes (odds ratio [OR]: 2.41; 95% confidence interval [CI]: 1.02 to 5.68; p = 0.046), in-segment angiographic diameter stenosis (OR: 1.06; 95% CI: 1.03 to 1.09; p < 0.001), in-segment IVUS-MLA (OR: 0.30; 95% CI: 0.14 to 0.63; p = 0.001), stent underexpansion (minimal stent area <5.0 mm(2)), (OR: 2.91; 95% CI: 1.19 to 7.07; p = 0.019), proximal location of the IVUS-MLA (OR: 4.62; 95% CI: 1.75 to 12.18; p = 0.002), and a multifocal or diffuse ISR pattern (OR: 2.50; 95% CI: 0.99 to 6.28; p = 0.050). An in-segment angiographic diameter stenosis ≥69.5% (72% sensitivity, 74% specificity, area under the curve = 0.793) and an IVUS-MLA ≤1.9 mm(2) (67% sensitivity, 75% specificity, area under the curve = 0.756) best predicted a positive SPECT; however, the overall diagnostic accuracies were only 73% and 70%, respectively.In lesions with ISR, neither angiography nor IVUS accurately predicted an abnormal SPECT.

Relationship between intravascular ultrasound parameters and fractional flow reserve in intermediate coronary artery stenosis of left anterior descending artery: Intravascular ultrasound volumetric analysis

The objective of this study was to assess the relationship between intravascular ultrasound (IVUS) parameters, including volumetric analysis, and fractional flow reserve (FFR). Although it is known that coronary atherosclerosis burden measured by IVUS volumetric analysis is related with clinical outcomes, its relationship with functional significance remains unknown. Both IVUS and FFR were performed in 206 cases of intermediate stenosis of the left anterior descending artery (LAD). Myocardial ischemia was assessed by FFR and maximal hyperemia was induced by continuous intracoronary adenosine infusion. FFR < 0.80 was considered as significant inducible myocardial ischemia. We performed standard IVUS parameter measurements and volumetric analyses. IVUS parameter comparison was performed in the presence (n = 90) or absence (n =116) of significant myocardial ischemia. Lesions with minimal lumen area (MLA) ≥ 4.0 mm2 had FFR ≥ 0.80 in 91.4% of cases, while 50.9% of lesions with MLA < 4.0 mm2 had FFR < 0.80. The independent predictors of FFR < 0.80 were IVUS lesion length (odds ratio [OR]: 1.1, 95% confidence interval [CI] = 1.06–1.18, P < 0.001) and MLA significance according to the lesion location (OR: 7.01, 95% CI = 3.09–15.92, P = 0.001). FFR correlated with plaque volume (r = −0.345, P < 0.001) and percent atheroma volume (PAV) (r = −0.398, P < 0.001). Lesions with significant ischemia (FFR < 0.80) as compared to those with FFR > 0.80 were associated with larger plaque volume (181.8 ± 82.3 vs. 125.9 ± 77.9 mm3, P < 0.001) and PAV (58.9 ± 5.6 vs. 53.8 ± 7.9%, P < 0.001). IVUS parameters representing severity and extent of atheromatous plaque correlated with functional significance in LAD lesions with intermediate stenosis.