Intravascular Ultrasound Measurements Research Articles

The uric acid/HDL-C ratio may predict significant coronary stenosis in moderate left main coronary artery lesions: an intravascular ultrasonography study

BackgroundThere may be severe difficulties in determining the severity of LMCA (left main coronary artery) lesions. The use of intravascular ultrasound (IVUS) facilitates decisions about lesion severity in these patients. The aim of this study was to investigate the relationship between the UHR (uric acid to HDL-C ratio) and lesion severity in patients who underwent LMCA IVUS.MethodsThis study included 205 patients with ICS (intermediate coronary stenosis) in the LMCA who underwent IVUS. In the IVUS measurements of these patients, the plaque burden (PB) and the minimal lumen area (MLA) showing lesion severity were measured.ResultsThe patients were separated into two groups according to plaque burden (< 65% and ≥ 65%). The UHR was significantly greater in the high plaque burden group (479.5 vs. 428.6, P = 0.001). When the patients were separated into two groups according to the MLA (< 6mm2 and ≥ 6mm2), the UHR was determined to be significantly greater in the group with low MLA (476.8 vs. 414.9, P < 0.001). In the ROC analysis performed according to the MLA and plaque burden values, the UHR cutoff value of 450 was found to have similar sensitivity and the same specificity for both parameters.ConclusionsThe results of this study suggested that there is a relationship between UHR and MLA < 6mm2 and plaque burden ≥ 65%, which are independently evaluated as critical in IVUS, and this could predict anatomically significant lesions in patients with a moderate degree of LMCA stricture.

Prospective Deep Learning-based Quantitative Assessment of Coronary Plaque by CT Angiography Compared with Intravascular Ultrasound.

Coronary computed tomography angiography provides noninvasive assessment of coronary stenosis severity and flow impairment. Automated artificial intelligence analysis may assist in precise quantification and characterization of coronary atherosclerosis, enabling patient-specific risk determination and management strategies. This multicenter international study compared an automated deep-learning-based method for segmenting coronary atherosclerosis in coronary computed tomography angiography (CCTA) against the reference standard of intravascular ultrasound (IVUS). The study included clinically stable patients with known coronary artery disease from 15 centers in the U.S. and Japan. An artificial intelligence (AI)-enabled plaque analysis service was utilized to quantify and characterize total plaque (TPV), vessel, lumen, calcified plaque (CP), non-calcified plaque (NCP), and low attenuation plaque (LAP) volumes derived from CCTA and compared with IVUS measurements in a blinded, core laboratory-adjudicated fashion. In 237 patients, 432 lesions were assessed; mean lesion length was 24.5 mm. Mean IVUS-TPV was 186.0 mm3. AI-enabled plaque analysis on CCTA showed strong correlation and high accuracy when compared with IVUS; correlation coefficient, slope, and Y intercept for TPV were 0.91, 0.99, and 1.87, respectively; for CP volume 0.91, 1.05, and 5.32, respectively; and for NCP volume 0.87, 0.98, and 15.24, respectively. Bland-Altman analysis demonstrated strong agreement with little bias for these measurements. Artificial intelligence enabled CCTA quantification and characterization of atherosclerosis demonstrated strong agreement with IVUS reference standard measurements. This tool may prove effective for accurate evaluation of coronary atherosclerotic burden and cardiovascular risk assessment.[ClinicalTrails.gov identifier: NCT05138289].

Diagnostic performance of ultrasonic flow ratio versus quantitative flow ratio for assessment of coronary stenosis

BackgroundUltrasonic flow ratio (UFR) is a novel intravascular ultrasound (IVUS)-derived modality for fast computation of fractional flow reserve (FFR) without pressure wires and adenosine. AimsThis study was sought to compare the diagnostic performance of UFR and quantitative flow ratio (QFR), using FFR as the reference standard. MethodsThis is a retrospective study enrolling consecutive patients with intermediate coronary artery lesions (diameter stenosis of 30%–90% by visual estimation) for IVUS and FFR measurement. UFR and QFR were performed offline in a core-lab by independent analysts blinded to FFR. ResultsFrom December 2022 to May 2023, a total of 78 eligible patients were enrolled. IVUS and FFR measurements were successfully conducted in 104 vessels, finally 98 vessels with both FFR, UFR and QFR evaluation were analyzed. Mean FFR was 0.79 ± 0.12. UFR showed a strong correlation with FFR similar to QFR (r = 0.83 vs. 0.82, p = 0.795). Diagnostic accuracy of UFR was non-inferior to QFR (94% [89%–97%] versus 90% [84%–94%], p = 0.113). Sensitivity and specificity in identifying hemodynamically significant stenosis were comparable between UFR and QFR (sensitivity: 89% [79%–96%] versus 85% [74%–92%], p = 0.453; specificity: 97% [91%–99%] versus 95% [88%–99%], p = 0.625). The area under curve for UFR was 0.95 [0.90–0.98], non-inferior to QFR (difference = 0.021, p = 0.293), and significantly higher than minimum lumen area (MLA; difference = 0.13, p < 0.001). Diagnostic accuracy of UFR and QFR was not statically different in bifurcation nor non-bifurcation lesions. ConclusionsUFR showed excellent concordance with FFR, non-inferior to QFR, superior to MLA. UFR provides a potentiality for the integration of physiological assessment and intravascular imaging in clinical practice.

Assessment of Bridging Stents in In Situ Laser Fenestrations of Aortic Endografts With Intravascular Ultrasound

ObjectiveTreatment of complex aortic aneurysms with the in situ laser fenestration (ISLF) technique involves implantation of a balloon expandable stent graft (bSG) in the created fenestration. Adequate expansion of this bSG is of importance both to achieve seal and to ensure target vessel stability. This experimental study assessed the expansion rate of different bSGs in the ISLF setting using intravascular ultrasound (IVUS). MethodsA commercially available aortic endograft was used to test the laser fenestration technique (Zenith Alpha, Cook Medical LLC, Bloomington, IN, USA). The ISLF was stented with the following bSGs: two Gore Viabahn VBX balloon expandable endoprostheses (WL Gore & Associates, Bloomington, IL, USA), three BeGraft Peripheral and three BeGraft Plus (Bentley InnoMed GmbH; Hechingen, Germany), and three Advanta V12 (Atrium, Hudson, NH, USA). The bSGs were expanded in three steps: (1) nominal, (2) rated burst pressure, and (3) dilatation with a non-compliant balloon at 15 atmospheres. After each step, an IVUS assessment of the bSG minimal diameter and the area at the fenestration (FA) and in a fully expanded segment distal to the fenestration (SA) was performed. A mean of the three IVUS measurements was used as the value for comparison. An insufficient bSG expansion was defined as a mean of FA/SA of < 0.8 (i.e., < 80% expansion). ResultsThe VBX was the only bSG that could be expanded to its intended diameter (i.e., at least 80%) at nominal pressure. The BeGraft Peripheral and BeGraft Plus showed the lowest expansion degrees after nominal and rated burst pressure. All bSGs that were tested reached a sufficient expansion degree after the use of a higher pressure balloon. ConclusionIn this ex vivo experiment, a dilatation up to nominal pressure showed satisfactory expansion only for the VBX. The consistency of the results when applied to the different types of stent grafts that were analysed reflects structural stent graft specific issues to consider when choosing the right device in cases of ISLF.

Diagnostic performance of intravascular ultrasound-based fractional flow reserve in evaluating of intermediate left main stenosis.

The recently introduced ultrasonic flow ratio (UFR), is a novel fast computational method to derive fractional flow reserve (FFR) from intravascular ultrasound (IVUS) images. In the present study, we evaluate the diagnostic performance of UFR in patients with intermediate left main (LM) stenosis. This is a prospective, single center study enrolling consecutive patients with presence of intermediated LM lesions (diameter stenosis of 30%-80% by visual estimation) underwent IVUS and FFR measurement. An independent core laboratory assessed offline UFR and IVUS-derived minimal lumen area (MLA) in a blinded fashion. Both UFR and FFR were successfully achieved in 41 LM patients (mean age, 62.0 ± 9.9 years, 46.3% diabetes). An acceptable correlation between UFR and FFR was identified (r = 0.688, P < 0.0001), with an absolute numerical difference of 0.03 (standard difference: 0.01). The area under the curve (AUC) in diagnosis of physiologically significant coronary stenosis for UFR was 0.94 (95% CI: 0.87-1.01), which was significantly higher than angiographic identified stenosis > 50% (AUC = 0.66, P < 0.001) and numerically higher than IVUS-derived MLA (AUC = 0.82; P = 0.09). Patient level diagnostic accuracy, sensitivity and specificity for UFR to identify FFR ≤ 0.80 was 82.9% (95% CI: 70.2-95.7), 93.1% (95% CI: 82.2-100.0), 58.3% (95% CI: 26.3-90.4), respectively. In patients with intermediate LM diseases, UFR was proved to be associated with acceptable correlation and high accuracy with pressure wire-based FFR as standard reference. The present study supports the use of UFR for functional evaluation of intermediate LM stenosis.

Impact of prolonged drug-coated balloon inflation on residual stenosis and clinical outcomes in coronary artery disease patients: A propensity score matched analysis.

There is a paucity of data regarding the optimal duration of drug-coated balloon (DCB) inflation for coronary lesions. We sought to explore the effect of DCB angioplasty with versus without long inflation time on residual stenosis and clinical outcomes in patients with coronary artery disease. This study included 314 consecutive patients with 445 lesions undergoing paclitaxel DCB angioplasty using different inflation time, divided according to whether the total inflation time of the DCB was ≥180 s (prolonged group) or <180 s (standard group). The primary clinical endpoint, defined as a composite of all-cause death, myocardial infarction, stroke, or target lesion revascularization, was examined in 92 propensity score matched pairs. In the matched cohort, the median clinical follow-up period was 947 days. Postprocedural angiographic diameter stenosis was smaller in the prolonged group than in the standard group (30.0% [22.0-37.0] vs. 33.5% [25.5-40.5]; p = 0.042). Intravascular ultrasound measurements revealed that longer DCB inflation time resulted in smaller area stenosis (66.6 ± 7.8% vs. 69.4 ± 7.0%; p = 0.044) and a less mean increase in percent atheroma volume (-11.2 ± 7.1% vs. -7.4 ± 5.9%; p = 0.004) after angioplasty. The rate of the primary endpoint was lower in the prolonged group than in the standard group (log-rank p = 0.025). The efficacy of prolonged DCB inflation was prominent in patients with in-stent restenosis and longer lesions. Prolonged DCB inflation was associated with reduced residual stenosis and improved clinical outcomes in patients with coronary artery disease undergoing percutaneous coronary intervention. Prospective randomized trials are warranted to validate the benefits of DCB angioplasty with long inflation time.

Accuracy of IVUS-Based Machine Learning Segmentation Assessment of Coronary Artery Dimensions and Balloon Sizing

BackgroundAccurate intravascular ultrasound (IVUS) measurements are important in IVUS-guided percutaneous coronary intervention optimization by choosing the appropriate device size and confirming stent expansion. ObjectivesThe purpose of this study was to assess the accuracy of machine learning (ML) automatic segmentation of coronary artery vessel and lumen dimensions and balloon sizing. MethodsUsing expert analysis as the gold standard, ML segmentation of 60 MHz IVUS images was developed using 8,076 IVUS cross-sectional images from 234 patients, which were randomly split into training (83%) and validation (17%) data sets. The performance of ML segmentation was then evaluated using an independent test data set (437 images from 92 patients). The endpoints were the agreement rate between ML vs experts’ measurements for appropriate balloon size selection, and lumen and acute stent areas. Appropriate balloon size was determined by rounding down from the mean vessel diameter or rounding up from the mean lumen diameter to the next balloon size. The difference of lumen area ≥0.5 mm2 was considered as clinically significant. ResultsML model segmentation correlated well with experts’ segmentation for training data set with a correlation coefficient of 0.992 and 0.993 for lumen and vessel areas, respectively. The agreement rate in lumen and acute stent areas was 85.5% and 97.0%, respectively. The agreement rate for appropriate balloon size selection was 70.6% by vessel diameter only and 92.4% by adding lumen diameter. ConclusionsML model IVUS segmentation measurements were well-correlated with those of experts and selected an appropriate balloon size in more than 90% of images.

Transabdominal ultrasound accurately identifies a significant iliac vein area-reducing lesion in patients with pelvic venous insufficiency

BackgroundIn patients with pelvic venous disorders secondary to pelvic venous insufficiency (PVI), the optimal imaging modality is ill-defined. Transabdominal ultrasound (TAU) is widely used to identify the presence of iliac vein stenosis. The purpose of the present investigation is to determine the accuracy of TAU for determining the presence of an iliac vein area-reducing lesion compared with intravascular ultrasound (IVUS). MethodsFrom January to December 2020, a retrospective review of prospectively collected data from 96 patients treated for symptomatic PVI at the Center for Vascular Medicine was performed. All patients had complete history and physical examination findings, demographics, CEAP (clinical, etiologic, anatomic, pathophysiologic), revised venous clinical severity score, and TAU, diagnostic venography, and IVUS measurements recorded in our electronic medical record system. All TAU measurements were performed by the same ultrasound technician with the patient in the supine position. Iliac vein diameters of the common femoral, external iliac, and common iliac veins and the inferior vena cava were obtained. Differences in body habitus were normalized by dividing the minimum diameter measurement of the stenotic vessel with that of the ipsilateral common femoral vein, subtracting this number from 1 and multiplying by 100 (stenosis = [1 − minimal diameter/common femoral diameter] × 100). The normalized stenoses were then compared with the IVUS-derived area reducing measurements. A receiver operating characteristic curve was created, and logistic regression analysis for the probability of predicting an area-reducing lesion of >50% and >60% with TAU was performed. The sensitivity, specificity, and positive and negative predictive values were calculated. ResultsThe average age of the entire cohort was 49.8 ± 13.5 years, with 69 women and 27 men. The CEAP distribution was as follows: C0, 5%; C1, 5%; C2, 10%; C3, 40%; C4a,b, 30%; C5, 7%; and C6, 3%. The average revised venous clinical severity score was 6.2 ± 2.6. The indications for intervention were leg symptoms alone in 43%, pelvic symptoms alone in 3%, and combined leg and pelvic symptoms in 54%. TAU identified a stenosis of ≥50% in 92 of the 96 patients (96%). For a ≥50% stenosis, a normalized diameter of ≤3 mm demonstrated a sensitivity, specificity, and positive and negative predictive value of 75%, 75%, 98%, and 12%, respectively. Logistic regression analysis indicated that TAU was significant in predicting the presence of a ≥60% area-reducing lesion (odds ratio, 1.03; 95% confidence interval, 1.01-1.05; P = .009). The area under the receiver operating characteristic curve (c-statistic) was 68.6%. The sensitivity, specificity, and positive and negative predictive values were 66.7%, 66.7%, 81.5%, and 47.6%, respectively, for a normalized diameter of ≥4 mm. ConclusionsThe ability of TAU to identify an iliac vein stenosis of ≥50% is 96%. The positive predictive value for TAU to identify a ≥60% iliac vein area-reducing lesion is high, with moderate sensitivity and specificity. For patients with symptoms consistent with pelvic venous disorders secondary to PVI, TAU is a good preintervention screening modality for properly trained vascular imaging specialists with findings that correlate well with IVUS measurements.

Reproducibility of Femoropopliteal Artery Intravascular Ultrasound Imaging in Patients With Peripheral Artery Disease

Despite increased use of intravascular ultrasound (IVUS) during peripheral artery interventions, evidence for reproducibility of IVUS measurements and its relation to angiography is lacking. Forty cross-sectional IVUS images of the femoropopliteal artery from 20 randomly selected patients enrolled in the XLPAD (Excellence in Peripheral Artery Disease) registry who underwent peripheral artery interventions and met criteria based on IVUS consensus guidelines were independently assessed by 2 blinded readers. IVUS images from 6 patients (40 images) were selected for angiographic correlation and met criteria for identifiable landmarks (e.g., stent edge and bifurcation). Lumen cross-sectional area (CSA), external elastic membrane (EEM) CSA, luminal diameter, and reference vessel diameter were repeatedly measured. The Lumen CSA and EEM CSA intra-observer agreement by Spearman rank-order correlation (ρ) was >0.993, intraclass correlation coefficient was >0.997, and repeatability coefficient was <1.34. For the interobserver measurement of luminal CSA and EEM CSA, the ρ=0.742 and 0.764; intraclass correlation coefficient=0.888 and 0.885; and repeatability coefficient=7.24 and 11.34, respectively. A Bland-Altman plot for lumen and EEM CSA showed good reproducibility. For angiographic comparison, the ρ for luminal diameter, luminal area, and vessel area were 0.419, 0.414, and 0.649, respectively. Femoropopliteal IVUS measurements showed strong intra-observer and interobserver agreement; IVUS and angiographic measurements did not demonstrate a similar strong agreement.

Intravascular ultrasound imaging in evaluation of aortic stiffness: A proof-of-concept study.

Aortic stiffness is a well-known cardio-vascular risk factor. For years, different methods have been studied in the assessment of aortic elastic properties and large arterial stiffness for risk stratification. Herein is an assessment of the role of intravascular ultrasound (IVUS) imaging for the evaluation of aortic elastic properties. Intravascular ultrasound imaging of the aorta was performed in 12 patients with transthoracic echocardiography (TTE) and computed tomography (CT) evidence for enlargement of the ascending aorta - diameter ≥ 40.0 mm. Mechanical properties of the aorta were derived from the measured diameters and intra-aortic pressure. Paired samples T-test analyses were performed to determine differences between measurements derived by TTE, CT and IVUS. Mean values of the calculated elastic properties via IVUS of the ascending aorta were as follows: compliance 0.021 ± 0.02; strain 205 ± 4.3; aortic stiffness index 4.3 ± 0.75; elastic modulus 0.31 ± 0.05. On paired T-test analysis maximum ascending aortic diameter measured by CT aortography and IVUS did not differ significantly (t = -0.19, p = 0.985), but a significant difference between IVUS measurements and TTE derived diameters was found (t = 13.118, p = 0.034). On average, IVUS diameters were 2.3 mm larger than the results acquired by TTE (95% confidence interval: 14.21-17.13). Intravascular ultrasound examination of the ascending aorta provided larger diameters than the ones collected by means of TTE. However, IVUS measurements did not differ significantly from diameters derived by CT aortography.

Preliminary study of the significance of reverberation by IVUS detection for patients with severe calcified lesions.

To explore the potential significance of the reverberation of calcification by comparing both intravascular ultrasound (IVUS) and optical coherence tomography (OCT) measurement post manual coregistration. The reverberation phenomenon is often detected by IVUS for severe calcified lesions post rotational atherectomy (RA), which is thought to be due to the glassy and smooth inner surfaces of calcifications. Because of the poor penetration of IVUS, it is impossible to measure the thickness of calcifications, and the relationship between multiple reverberations and the thickness of calcification lesions has not been reported before. A total of forty-nine patients with severe calcified coronary lesions that were detected by IVUS and OCT simultaneously were enrolled in our retrospective study. If reverberation phenomena were detected by IVUS, intravascular imaging (IVI) data (including distance between the IVUS catheter center and the inner surface of the reverberation signal, the intervals between all adjacent reverberation signals, the number of layers of reverberation in IVUS, and the thickness of the calcification in OCT) were measured at the same position and same direction (each cross-section had 4 mutually perpendicular directions) at 1-mm intervals. The correlation between each reverberation observational value and OCT data was the primary target in this retrospective study, and the correlation between reverberation and calcium crack post predilatation was analyzed in other 15 patients. Four hundred twenty-eight valid observational points were analyzed simultaneously by IVUS and OCT; among them, 300 points had a single layer of reverberation, 83 had double layers of reverberation and 42 had multiple layers (≥ 3 layers) of reverberation by IVUS detection post-RA. Multivariate logistic regression analysis showed that the number of layers of reverberation by IVUS was significantly related to the thickness of calcifications by OCT at the same point and in the same direction (p < 0.001). Single, double, and multiple layers of reverberation in IVUS correspond to median calcification thicknesses (interquartile ranges (IQRs)) of 0.620mm (0.520-0.720), 0.950mm (0.840-1.040) and 1.185mm (1.068-1.373), respectively, by OCT detection. Another 100 points in other 15 patients with integrated IVUS data pre- and post-predilatation showed that only single layer of reverberation was related to calcium crack (p < 0.001). The number of layers of reverberation signal detected by IVUS is positively correlated with the thickness of calcifications measured by OCT post-RA and single layer of reverberation is correlated to calcium crack post-predilatation.

Abstract 12383: Large Field-of-View Intravascular Ultrasound for Peri-Procedural Assessment of Stent Frame Expansion After Transcatheter Heart Valve-in-Valve

Introduction. It is unknown whether large field-of-view intravascular ultrasound (IVUS) can be a valid peri-procedural imaging tool to assess actual expansion of transcatheter heart valve (THV) during valve-in-valve procedures. Hypothesis. To compare % expansion of SAPIEN 3 THV measured with peri-procedural IVUS versus post-procedural cardiac gated contrast multi-slice computer tomography (MSCT). Expansion was defined as actual outer frame area/nominal area x 100%. Methods. Studied were patients with successful valve-in-valve for failed surgical mitral and tricuspid bioprosthetic valves. All underwent peri-procedural IVUS using 10MHz Vision PV035 (Philips North America Corporation, Andover, USA) and post-procedural MSCT (SOMATOM Definition Flash, Dual Source, SIEMENS). IVUS and MSCT (Syngo Via, Siemens, Germany) measurements were off -line and done at 1-mm step along the entire height of SAPIEN 3 THV (height 18, 20 and 22 mm for the Sapien THV 23, 26 and 29 mm, respectively). Results. Five patients (68.8±11.2 years, 3 female) were treated for failed surgical mitral (n=3) and tricuspid (2) bioprosthetic valves using SAPIEN 3 THV size 23mm (n=1), 26mm (n=1), and 29mm (n=3). Mean peri-procedural and pre-discharge residual transvalvular gradient differed substantially (1.9±0.9 vs 7.9±1.1mmHg, p=0.001). In total, 104 corresponding cross-sections of the THVs were measured with both IVUS and MSCT. Actual outer-frame SAPIEN 3 expansion was smaller within the lengths of inflow and mid segment (overlapping the ring) than in the outflow, being substantially smaller than nominal (Fig 1). Overall, there was very good agreement between % expansion of THV stent frame assessed in IVUS and MSCT (93.5%±13.3% vs 96.3%±11.3%; r =0.976 and p&lt;0.001). Conclusions. Peri-procedural use of large field-of-view IVUS offers an accurate insight into actual THV expansion deployed valve-in-valve. Figure 1. % expansion of SAPIEN 3 measured in IVUS and MSCT.

Efficacy and utilization of intravascular ultrasound in office-based lower extremity endovascular interventions for peripheral arterial disease.

Intravascular ultrasound (IVUS) is a uniquely objective but underutilized imaging modality in the interventional treatment of peripheral arterial disease treatment. IVUS has been shown to improve device size selection and diagnose occult pathology difficult to see with routine angiography. We hypothesize that the use of IVUS in lower extremity endovascular intervention improves accuracy in stent and balloon size selection and minimizes contrast use. This is a retrospective case series performed at a single-institution outpatient center by two vascular surgeons from July 2016 through July 2017. We identified 94 total IVUS-assisted procedures. We collected data regarding demographics, balloon and stent size, IVUS-determined vessel diameter, pre-procedure and post-procedure ABI values, and contrast used during the procedure. An independent core laboratory was further utilized to characterize all IVUS and angiographic size vessel measurements. For the 94 lower extremity IVUS-assisted interventions, the average patient age was 70±9 years old, with an average contrast use of 37.1mL of Omnipaque 300. There was substantial improvement in pre- and post-procedure ABI (0.7±0.23 to 0.94±0.21). On analysis of average intraluminal IVUS vessel diameter to balloon angioplasty used, we had a correlation in size of 0.96±0.16 in our series. Additionally, in eight instances IVUS allowed for identification of a flow-limiting dissection with subsequent stenting. Routine use of IVUS offers a powerful diagnostic paradigm that has the potential to significantly decrease contrast use and to improve objectivity in choosing appropriate vascular tools to maximize intra-procedural efficacy. The discovery of adverse findings not initially noticed on angiography further reinforces the value of IVUS utilization.

Current concepts of optical coherence tomography assessment of left main coronary artery during coronary interventions

Conventional angiography is poor in assessing type of plaque, plaque volume, disease extent, severity and features associated with optimization of percutaneous coronary intervention (PCI), whereas Intra-Vascular Ultra-Sound (IVUS) and optical coherence tomography (OCT) overcome these limitations by providing cross sectional images of vessel wall, and longitudinal extent of disease. OCT provides high-resolution images at the cost of limited penetration compared with IVUS with an axial spatial resolution of 10–20 μm versus 100–200 μm, lateral resolution of 20 μm versus 200 μm, and penetration depth 1–2.5 mm versus 10 mm, respectively. OCT measurements were proved to be nearer to the actual luminal areas whereas IVUS measurements were overestimated and were less reproducible in the phantom model. OCT and IVUS are proved to be a valid guidance for optimization of PCI. However, usefulness of OCT in day to day practice is very limited in the assessment of Left Main disease. Both imaging technologies have different distinct features, these are complementary and should be opted carefully for each patient based on pros and cons, and clinical indications of each technique.

Impact of Baseline and Postprocedural Intravascular Ultrasound Findings on 1-Year Primary Patency After Drug-Coated Balloon Treatment of Femoropopliteal Lesions

Purpose: Drug-coated balloons (DCBs) are commonly used for endovascular treatment of femoropopliteal lesions. Here, we employed intravascular ultrasound (IVUS) to investigate the predictors of restenosis after DCB treatment. Methods: This retrospective and single-center study was performed to examine 1-year primary patency after DCB treatment and to identify the risk factors for restenosis by analyzing clinical characteristics, angiographic findings, and IVUS measurements. We included 111 consecutive patients undergoing DCB treatment for de novo femoropopliteal lesions at our hospital from July 2018 to March 2020. Results: The primary patency rate was found to be 80.0% at 1 year. The Cox proportional hazard multivariate analysis revealed that restenosis was independently associated with chronic total occlusion (CTO; p < 0.001), circumferential calcification (p = 0.023), and smaller postprocedural minimum lumen area (MLA; p = 0.036). Furthermore, receiver operating characteristic curve analysis showed that the cutoff value of postprocedural MLA to prevent restenosis was 12.7 mm2, with an area under the curve of 0.774 (p< 0.001). The multivariate analysis indicated that patients with a postprocedural MLA below 12.7 mm2 (n = 44) had a significantly smaller distal reference vessel size (p < 0.001) compared to those with a postprocedural MLA over 12.7 mm2 (n = 67). Conclusions: Restenosis after DCB treatment was shown to correlate with CTO, circumferential calcification, and postprocedural MLA as evaluated by IVUS. Moreover, smaller vessel sizes might represent a particular challenge to the DCB strategy due to the difficulty of restoring a sufficient postprocedural lumen area by balloon dilatation.

Clinical decision making in frequently encountered anomalous aortic origin of coronary arteries, the impact of IVUS

Abstract Introduction The aim in the diagnostic work-up of patients with an anomalous aortic origin of coronary arteries (AAOCA) is to determine whether the course of the coronary artery is benign or malignant. In patients with AAOCA with an interarterial course the guidelines on diagnostics are concise. Recommended CT-scan imaging does not evaluate stress-induced functional consequences like external compression by the pulmonary artery as the scan is performed in a resting state. Non-invasive ischemia detection techniques often lack sufficient sensitivity. To improve functional stratification, exploration of new diagnostic modalities in the diagnostic workup of AAOCA is mandatory. Purpose The purpose is to explore the potential role of intravascular ultrasound (IVUS) in the diagnostic workup of patients with AAOCA. Methods Nine patients with an anomalous right coronary artery with an interarterial course were analyzed. A cardiologist evaluated the complaints. Anatomical features of the AAOCA were assessed with CT-scan imaging. Further analyses included ischemia detection and coronary angiography. To assess stress-induced ischemia IVUS and invasive measurements – fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) – were performed at rest and during adrenaline-induced stress. A slit-like orifice was classified as a width/length (W/L) ratio of ≤0.50, an oval orifice as 0.51–0.9 and a round orifice as &amp;gt;0.91. Results Potential cardiac complaints were present in seven patients. In 8 (89%) patients CT-images showed an acute angle, in 8 (89%) proximal narrowing and an aortic take-off above the pulmonary valve in 4 (44%). In 7 (78%) patients a slit-like orifice and in two (22%) an oval orifice were observed (table 1). IVUS at rest showed a slit-like orifice in one patient classified as an oval orifice on the CT-images and vice versa in another patient (table 2). The patients classified as an oval orifice with IVUS showed no external compression during adrenaline-induced stress. In 4 (57%) out of 7 patients with an slit-like orifice on IVUS, the width remained unchanged or increased during adrenaline infusion. In 2 patients the width decreased slightly, however, these patients were asymptomatic and no ischemia was detected. In 1 (14%) patient the width remained 1.4mmm and the length increased from 3.2mm to 4.7mm. In this case the vessel ostium was fully engaged with the IVUS catheter, hence, the width could not decrease during adrenaline infusion. This was regarded as external compression. In addition, in this patient ischemia was detected. Conclusion(s) In two (22%) out of 9 patients IVUS gave a better insight of the shape of the orifice than CT. Additionally, the anatomic and functional-dynamic components of compression could be defined with adrenaline-induced stress. Therefore, IVUS can contribute to a better understanding of the functional consequences of the anatomical features and of potential stress-induced external compression. Funding Acknowledgement Type of funding sources: None. Table 1Table 2

Intravascular ultrasound for valve frame expansion and orifice area measurement as well as paravalvular leak assessment during transcatheter aortic valve replacement

Abstract Introduction Valve frame expansion (measured outer valve frame area/nominal valve dimension), but not oversizing (nominal valve dimension/annulus area, %) determines pattern of restored blood flow after transcatheter aortic valve replacement (TAVR). There is no online measure of frame expansion, and error in current echocardiographic assessment of effective orifice area (EOA) and paravalvular leak (PVL) are common. Purpose To evaluate large imaging field intravascular ultrasound (IVUS) during TAVR for measuring valve geometry [frame expansion, minimal geometric orifice area (min GOA), and mechanism of PVL] with transthoracic echo and angio-CT serving for comparative measures, along with the nominal EOA as established by Hahn et al. Methods After successful TAVR either a 10MHz Vision PV 0.035" (60mm imaging field) or 20MHz Vision PV 0.018" (24mm imaging field plus Chr omaFlo) IVUS catheter (Philips) was slowly pulled from the left ventricle outflow (LVOT) to the aorta with continuous imaging of the aortic root. Results There were 16 pts (80.8±7.1 yrs, 8 female) treated for de novo aortic stenosis (n=15) or failed bioprosthesis (n=1), 7 of whom were treated with balloon-expandable TAVR. PV 0.35" catheters were used in 8 pts (including valve-in-valve) and allowed complete geometry assessment of 26.6±2.7mm nominal prosthesis Ø (Figure 1A) whereas PV 0.018" allowed complete geometry assessment in only 4 of 8 pts with nominal prosthesis Ø of 26.1±2.8mm (Figure 1B). Actual % valve inflow expansion (IVUS outer frame/valve nominal dimension) was significantly smaller than % valve oversizing (80%±19% vs 125±19%, p=0.005). Min GOA was substantially bigger than corresponding nominal EOA and EOA calculated using the post-procedural LVOT diameter (272±84mm2 vs 174±25mm2 vs 181±59mm2, p=0.001 correspondingly). However, min GOA was similar to EOA calculated using baseline LVOT area (272±84mm2 vs 230±90mm2; r=0.713, p=0.009). IVUS and angio-CT measurements of outer prosthesis frame area were similar for inflow, coaptation site, and outflow (460±143mm2 vs 454±134mm2 and 455±134mm2 vs 447±114mm2 and 722±174mm2 vs 725±180; p≤0.001 for all paired correlations). Inflow expansion (IVUS outer frame/baseline CT annulus area) tended to be smaller among valves with ≥mild vs no PVL (95±14% vs 107±11%, p=0.156), with clear ChromaFlo signal seen in the space between the aortic annulus wall and outer-valve frame surface (Figure 1C). Conclusions Large imaging field IVUS during TAVR allows for peri-procedural assessment of actual valve geometry that differs substantially from nominal. IVUS offers online tomographic perspective and highest accuracy in anatomy evaluation corresponding with valve function. Funding Acknowledgement Type of funding sources: None. Figure 1

Intravascular ultrasound for peri-procedural geometric orifice area measurement during transcatheter pulmonary valve replacement

Abstract Introduction Large imaging filed intravascular ultrasound (IVUS) offering superior online tomographic perspective and visual accuracy could guide transcatheter pulmonary valve replacement (TPVR) for right ventricular outflow tract (RVOT) insufficiency. It is unknown whether geometric orifice area (GOA) measured by IVUS corresponds with effective orifice area (EOA) measure by transthoracic echocardiography (TTE) after successful TPVR. Purpose To compare minimal inner-leaflets cross-sectional area delineated in systole (min GOA) measured by IVUS versus EOA calculated = right ventricle stroke volume (measured in baseline cardiac magnetic resonance) / pulmonary valve velocity time integral (measured early post-procedure by Vivid e95). Methods After successful TPVR a 10MHz Vision PV 0.035" (60mm imaging field) IVUS catheter was slowly pulled from the distal pulmonary artery to the right ventricle with continuous imaging of RVOT. IVUS measurements included inner-valve dimension for several evenly spaced cross-sections along the entire length and perpendicular to RVOT long axis. Measured were outer-frame diameters (minimal and maximal) and its cross-sectional area, and cross-sectional area of the visual orifice (min GOA) identified exclusively at the coaptation site (Fig 1). Results There were 11 pts (median age 30 [25–36] yrs, 4 ♀, all but one with Tetralogy of Fallot) who had undergone prior corrective surgery (5 transannular patch, 2 bioprosthetic valve or 4 pulmonary homograft). Overall, 176 cross-sections were analyzed. Overall, min GOA measured 3.7±1.0cm2, and was 68%±9% of the valve-outer area (5.5±1.5cm2). It was substantially larger than calculated EOA (3.7±1.0cm2 vs 2.0±0.5cm2; p&amp;lt;0.001). The ratio of max/min GOA diameter was 1.11±0.11 signifying low eccentricity and was not related to EAO. Conclusions After successful balloon-expandable valve implantation to treat RVOT insufficiency, geometric orifice dimension was significantly smaller then outer valve frame dimension. Visual measure of geometric orifice area during the procedure using IVUS documented its circularity and indicated that it was larger than EOA calculated upon functional measure. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): This work was supported by the research grant (2.4/VI/18) founded by the National Institute of Cardiology in Warsaw (Poland). IVUS visualization of ES3.

Peripheral microvascular dysfunction is associated with plaque progression and adverse long-term outcomes in heart transplant patients.

AimsCardiac allograft vasculopathy (CAV) is the major cause of increased morbidity and mortality after heart transplantation. Peripheral endothelial dysfunction (PED) is associated with early atherosclerosis and future risk of major adverse cardiovascular events (MACE) in non‐heart transplant population. We aimed to investigate the association of PED with future MACE, and plaque progression assessed by intravascular ultrasound (IVUS) after heart transplantation.Methods and resultsWe included 66 transplant patients who underwent serial IVUS surveillance for CAV and baseline assessment of peripheral endothelial function using reactive hyperaemia peripheral arterial tonometry. PED was defined as reactive hyperaemia index < 2. The primary endpoint of the study was to investigate the association of PED with CAV progression assessed by intravascular ultrasound (IVUS). CAV progression was assessed as the change (Δ) in plaque volume divided by segment length, and Δ plaque index (plaque volume/vessel volume), adjusted for the time between IVUS measurements (median 3.0 [2.2, 3.1] years). The secondary endpoint was to investigate the association between PED and future MACE, which was defined as any incident of revascularization, heart failure hospitalization, stroke, myocardial infarction, re‐transplantation, and death. Patients with PED (n = 27) had more yearly plaque progression (0.50 ± 0.66 vs. 0.15 ± 0.50 mm3/mm/year, P = 0.02) and a higher Δ plaque index (2.41 ± 2.53% vs. 0.69 ± 2.22%, P = 0.01). Patients with PED were more likely to experience MACE during a median follow‐up of 8.2 years (interquartile range [7.6, 8.4]), after adjustment for potential cofounders such as age, high‐density lipoprotein cholesterol levels, total rejection score, baseline International Society for Heart & Lung Transplantation CAV grade, and indication of transplantation. (hazard ratio 2.15, 95% confidence interval [1.09, 4.23], P = 0.03).ConclusionsPeripheral endothelial dysfunction is associated with increased plaque progression and adverse long‐term cardiovascular outcomes in transplant patients. PED assessment might be a useful clinical tool for risk stratification after heart transplantation.

Abnormal shear stress and residence time are associated with proximal coronary atheroma in the presence of myocardial bridging

BackgroundAtheromatous plaques tend to form in the coronary segments proximal to a myocardial bridge (MB), but the mechanism of this occurrence remains unclear. This study evaluates the relationship between blood flow perturbations and plaque formation in patients with an MB. Methods and resultsA total of 92 patients with an MB in the mid left anterior descending artery (LAD) and 20 patients without an MB were included. Coronary angiography, intravascular ultrasound, and coronary physiology measurements were performed. A moving-boundary computational fluid dynamics algorithm was used to derive wall shear stress (WSS) and peak residence time (PRT). Patients with an MB had lower WSS (0.46 ± 0.21 vs. 0.96 ± 0.33 Pa, p < 0.001) and higher maximal plaque burden (33.6 ± 15.0 vs. 14.2 ± 5.8%, p < 0.001) within the proximal LAD compared to those without. Plaque burden in the proximal LAD correlated significantly with proximal WSS (r = −0.51, p < 0.001) and PRT (r = 0.60, p < 0.001). In patients with an MB, the site of maximal plaque burden occurred 23.4 ± 13.3 mm proximal to the entrance of the MB, corresponding to the site of PRT. ConclusionsRegions of low WSS and high PRT occur in arterial segments proximal to an MB, and this is associated with the degree and location of coronary atheroma formation.