Evaluation of the thickness of coronary calcium by 60-MHz intravascular ultrasound: head-to-head comparison with optical frequency domain imaging

The region behind the coronary calcium could not be visualized by intravascular ultrasound (IVUS) because of acoustic shadow. However, some pathological studies have shown that IVUS delineated the vessel border behind thin coronary calcium sheets. This study aimed to reveal whether recent IVUS can visualize the region behind thin coronary calcium sheets. Using 534 cross-sectional optical frequency domain images (OFDI), including severe calcified coronary lesions, calcium sheet thickness was measured by every 1°. Accordingly, the visibility of the vessel border behind the coronary calcium sheet was evaluated using 60-MHz IVUS images, which were longitudinally linked with OFDI ones. After carefully coordinating with the axial position, the association between the IVUS-derived permeability of the coronary calcium sheet and calcium thickness was evaluated. The maximum and mean calcium thickness by OFDI was 0.88 ± 0.39 and 0.62 ± 0.30 mm, respectively. By 60-MHz IVUS, 12.1% of the coronary calcium sheets had permeable segments. Comparing between OFDI and IVUS images, 48.6% of the coronary calcium sheets with maximum thickness ≤ 0.3 mm were sometimes permeable by 60-MHz IVUS, whereas most > 0.5 mm thick calcium sheets were impermeable. In the receiver operating characteristic curve analysis, the best cutoff values for the maximum and mean thickness of permeable calcium were 0.48 and 0.31 mm, respectively. Thus, 60-MHz IVUS can occasionally visualize the region behind a thin coronary calcium sheet. When using 60-MHz IVUS, this finding may be a predictive marker of calcium sheet with a thickness of < 0.5 mm.

Predictive value of intravascular ultrasound for the function of intermediate coronary lesions

BACKGROUND

Intravascular ultrasound (IVUS) can provide detailed coronary anatomic parameters. The purpose of our study was to evaluate the parameters measured by IVUS for the prediction of intermediate coronary lesions function by referencing quantitative fraction ratio (QFR) ≤ 0.80 (vs. > 0.80).

METHODS

Eighty four cases with 92 intermediate coronary lesions in vessels with a diameter ≥ 2.50 mm were enrolled. Paired assessment of IVUS and cQFR was available, and vessels with cQFR ≤ 0.8 were considered the positive reference standard. Logistic regression was used to select model variables by a maximum partial likelihood estimation test and receiver operating characteristic curve (ROC) analysis to evaluate the diagnostic value of different indices.

RESULTS

Plaque burden (PB) and lesion length (LL) of IVUS were independent risk factors for the function of coronary lesions. The predictive probability P was derived from the combined PB and LL model. The area under the curve (AUC) of PB, (minimum lumen area) MLA, and LL and the predicted probability P are 0.789,0.732,0731, and 0.863, respectively (P < 0.01). The AUC of the predicted probability P was the biggest among them; the prediction accuracy of cQFR ≤ 0.8 was 84.8%, and the sensitivity of the diagnostic model was 0.826, specificity was 0. 725, and P < 0.01.

CONCLUSION

PB and LL of IVUS were independent risk factors influencing the function of intermediate coronary lesions. The model combining the PB and LL may predict coronary artery function better than any other single parameter.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention: Practical Application

Optical coherence tomography (OCT) provides high-resolution imaging of coronary arteries and can be used to optimize percutaneous coronary intervention (PCI). Intracoronary OCT, however, has had limited adoption in clinical practice. Novelty and relative complexity of OCT interpretation compared with the more established intravascular ultrasound, lack of a standardized algorithm for PCI guidance, paucity of data from randomized trials, and lack of rebate for intravascular imaging have contributed to the modest practical adoption of OCT. We provide a practical step-by-step guide on how to use OCT in PCI, including device set-up, simplified image interpretation, and an algorithmic approach for PCI. optimization.

A State-Of-The-Art Review on Coronary Artery Border Segmentation Algorithms for Intravascular Ultrasound (IVUS) Images

Intravascular Ultrasound images (IVUS) is a useful guide for medical practitioners to identify the vascular status of coronary arteries in human beings. IVUS is a unique intracoronary imaging modality that is used as an adjunct to angioplasty to view vessel structures using a catheter with high resolutions. Segmentation of IVUS images has always remained a challenging task due to various impediments, for example, similar tissue components, vessel structures, and artifacts imposed during the acquisition process. Many researchers have applied various techniques to develop standard methods of image interpretation, however, the ultimate goal is still elusive to most researchers. This challenge was presented at the MICCAI- Computing and Visualization for (Intra)Vascular Imaging (CVII) workshop in 2011. This paper presents a major review of recently reported work in the field, with a detailed analysis of various segmentation techniques applied in IVUS, and highlights the directions for future research. The findings recommend a reference database with a larger number of samples acquired at varied transducer frequencies with special consideration towards complex lesions, suitable validation metrics, and ground-truth definition as a standard against which to compare new and current algorithms.

High-definition intravascular ultrasound versus optical frequency domain imaging for the detection of calcium modification and fracture in heavily calcified coronary lesion

While optical frequency domain imaging (OFDI) can delineate calcium modification and fracture, the capability of high-definition intravascular ultrasound (HD-IVUS) for detecting these remains unclear. This study evaluated diagnostic accuracy of HD-IVUS for assessing calcium modification and fracture as compared to OFDI. HD-IVUS and OFDI were used during orbital or rotational atherectomy procedures conducted for 21 heavily calcified coronary lesions in 19 patients. With OFDI assessment used as the gold standard, diagnostic accuracies of HD-IVUS for calcium modification and fracture were compared every 1 mm to the matched pre-stenting images (n = 1129). Calcium modification, as assessed by OFDI, was defined as polished and concave-shaped calcium. For HD-IVUS, calcium modification was defined as the presence of reverberation with concave-shaped calcium. In both assessments, the definition of calcium fracture was defined as a slit or complete break in the calcium plate. Calcified plaque was found in 86.4% of analyzed OFDI images. Calcium modification and fracture were detected in 20.6% and 11.0% of detected calcified plaques. Sensitivity, specificity, positive and negative predictive values of HD-IVUS detection for calcium modification and fracture were 54.4%, 97.8%, 86.7%, 89.1% and 86.0%, 94.5%, 58.2%, 96.8%, respectively. Discordance cases between both assessments demonstrated that heterogeneous calcium visualized by OFDI, separated calcium, and guide wire artifact can be misdiagnosed. Diagnostic accuracies of HD-IVUS for assessing calcium modification and fracture were acceptable as compared to OFDI. Such findings can be of utility during imaging guided interventional procedures with atherectomy.

Case report: Dobutamine stress intracoronary physiology and imaging to examine the functional and dynamic properties of an apparent malignant intra-arterial right coronary artery

Background

We present a case concerning a 64-year-old female with complaints of palpitations, chest pain, and an anomalous right coronary artery (RCA) from the opposite sinus (R-ACAOS) with a suspected malignant trajectory on computed tomography. She was referred to our clinic for a second opinion to re-assess the suggested treatment of coronary surgery.

Case summary

A coronary angiogram was performed demonstrating a RCA with a tapered ostium typical for an inter-arterial course. Dobutamine and adenosine stress test during simultaneous intracoronary flow, pressure, and ultrasound assessment, was performed to determine the functional significance. After 120 mcg adenosine, intracoronary baseline flow velocity increased from 14 cm/s to a peak flow velocity of 37 cm/s, demonstrating a sufficient coronary flow velocity reserve (CFVR) of 2.6. No intracoronary pressure drop during maximal hyperaemia was found. After maximum dobutamine stress, CFVR was measured 2.5. Fractional flow reserve measured 0.99. Cross-sectional area measurement through intravascular ultrasound demonstrated a diameter reduction from 14.6 mm² to 8.5 mm². Therefore, we concluded this aberrant trajectory was not of any functional relevance and should be considered non-malignant.

Discussion

There are several anatomic coronary anomalies which may contribute to coronary compression during exercise and are therefore correlated with sudden cardiac death. Right coronary artery from the opposite sinus is correlated with a low mortality rate of 0.2% in comparison to left-ACAOS at 6.3% over 20 years in participants of competitive sport. Therefore, strong evidence of ischaemia must be present before opting for surgery. Our pragmatic approach provided in our opinion enough evidence for a conservative treatment strategy.

Fractional flow reserve for coronary stenosis assessment derived from fusion of intravascular ultrasound and X-ray angiography

Background

Intravascular ultrasound (IVUS) provides good insight into lumen boundary and plaques; however, it is still difficult to detect functionally significant stenosis from IVUS images for the guidance of coronary percutaneous intervention (PCI). This study aimed to develop a novel method to estimate fractional flow reserve (FFR) value for determining the functional significance of coronary artery disease through the fusion of IVUS and X-ray angiographic images.

Methods

We developed a novel approach to 3D vessel reconstruction by integrating IVUS with X-ray angiographic images. Based on the reconstructed geometry and the inlet flow derived from the thrombolysis in myocardial infarction (TIMI) frame count, a simplified fluid dynamics equation was established to compute the pressure drop and IVUS-derived FFR (AccuFFRivus) was subsequently obtained. To validate the feasibility and performance of this IVUS-based FFR method, we performed AccuFFRivus calculations on 32 coronary vessels with invasive FFR as the reference standard.

Results

Great correlation (r=0.86, P<0.001) was observed between AccuFFRivus and FFR. The area under the receiver-operating characteristic curve (AUC) was higher for AccuFFRivus than minimal lumen area (MLA, <4 mm²) and diameter stenosis rate (DS% ≥50%) [0.98 (95% CI: 0.86 to 1.0) vs. 0.78 (95% CI: 0.60 to 0.91) and 0.66 (95% CI: 0.47 to 0.82)]. Bland-Altman plot showed a mean difference value of -0.011 (limits of agreement: -0.156 to 0.134).

Conclusions

AccuFFRivus is a novel method for hybridizing IVUS and X-ray angiographic images to identify functionally significant stenosis with FFR ≤0.80. The good diagnostic performance from the initial validation study demonstrates the potential for clinical utilization of physiologically guided decision-making. Further validation is required in future studies with a large number of cases.

Ten things to know about ten imaging studies: A preventive cardiology perspective ("ASPC top ten imaging")

Knowing the patient's current cardiovascular disease (CVD) status, as well as the patient's current and future CVD risk, helps the clinician make more informed patient-centered management recommendations towards the goal of preventing future CVD events. Imaging tests that can assist the clinician with the diagnosis and prognosis of CVD include imaging studies of the heart and vascular system, as well as imaging studies of other body organs applicable to CVD risk. The American Society for Preventive Cardiology (ASPC) has published "Ten Things to Know About Ten Cardiovascular Disease Risk Factors." Similarly, this "ASPC Top Ten Imaging" summarizes ten things to know about ten imaging studies related to assessing CVD and CVD risk, listed in tabular form. The ten imaging studies herein include: (1) coronary artery calcium imaging (CAC), (2) coronary computed tomography angiography (CCTA), (3) cardiac ultrasound (echocardiography), (4) nuclear myocardial perfusion imaging (MPI), (5) cardiac magnetic resonance (CMR), (6) cardiac catheterization [with or without intravascular ultrasound (IVUS) or coronary optical coherence tomography (OCT)], (7) dual x-ray absorptiometry (DXA) body composition, (8) hepatic imaging [ultrasound of liver, vibration-controlled transient elastography (VCTE), CT, MRI proton density fat fraction (PDFF), magnetic resonance spectroscopy (MRS)], (9) peripheral artery / endothelial function imaging (e.g., carotid ultrasound, peripheral doppler imaging, ultrasound flow-mediated dilation, other tests of endothelial function and peripheral vascular imaging) and (10) images of other body organs applicable to preventive cardiology (brain, kidney, ovary). Many cardiologists perform cardiovascular-related imaging. Many non-cardiologists perform applicable non-cardiovascular imaging. Cardiologists and non-cardiologists alike may benefit from a working knowledge of imaging studies applicable to the diagnosis and prognosis of CVD and CVD risk - both important in preventive cardiology.

The role of intravascular ultrasound in percutaneous coronary intervention of complex coronary lesions

Intravascular ultrasound (IVUS) is a catheter-based coronary imaging technique. It utilises the emission & subsequent detection of reflected high frequency (30-60 MHz) sound waves to create high resolution, cross-sectional images of the coronary artery. IVUS has been the cornerstone of intracoronary imaging for more than two decades. When compared to the invasive coronary angiogram which studies only the silhouette of the contrast-filled artery lumen, IVUS also crucially images the vessel wall. Because of this capability, IVUS has greatly facilitated understanding of the coronary atherosclerosis process. Such insights from IVUS reveal how commonly and extensively plain angiography underestimates the true extent of coronary plaque, the characteristics of plaques prone to rupture and cause acute coronary syndromes (lipid rich, thin cap atheroma), and a realisation of the widespread occurrence of vessel remodelling in response to atherosclerosis. Similarly, IVUS has historically provided salutary mechanistic insights that have guided many of the incremental advances in the techniques of percutaneous coronary intervention (PCI). Examples include mechanisms of in-stent restenosis, and the importance of high-pressure post-dilatation of stents to ensure adequate stent apposition and thereby reduce the occurrence of stent thrombosis. IVUS also greatly facilitates the choice of correct diameter and length of stent to implant. Overall, a compelling body of evidence indicates that use of intravascular ultrasound in PCI helps to achieve optimal technical results and to mitigate the risk of adverse cardiac events. In this review, the role of intravascular ultrasound as an adjunct to PCI in complex coronary lesions is explored. The complex coronary situations discussed are the left main stem, ostial stenoses, bifurcation stenoses, thrombotic lesions, the chronically occluded coronary artery, and calcified coronary artery disease. By thorough review of the available evidence, we establish that the advantages of IVUS guidance are particularly evident in each of these complex CAD subsets. In particular, some consider the use of IVUS to be almost mandatory in left main PCI. A comparison with other intracoronary imaging techniques is also explored.

Progression of coronary atherosclerosis in patients without standard modifiable risk factors

Background and aims

The outcome of patients with clinical coronary artery disease despite traditional risk factors is poorly understood.

Methods

Clinical characteristics and plaque burden on serial intravascular ultrasonography were compared in patients without (n ​= ​165) and with (n ​= ​492) standard modifiable risk factors after matching on age, sex and use of statins from a database of 5823 patients participating in clinical trials of anti-atherosclerotic therapies.

Results

Patients without standard modifiable risk factors had lower baseline systolic blood pressure (118 ​± ​12 vs. 129 ​± ​17 ​mmHg, p ​< ​0.001), low-density lipoprotein cholesterol (87 ​± ​21 vs. 104 ​± ​34 ​mg/dl, p ​< ​0.001), triglycerides [106 vs. 136 ​mg/dl, p ​< ​0.001)] and C-reactive protein [1.5 vs. 2.1 ​mg/l, p ​= ​0.001]. At baseline, patients without modifiable risk factors had a lower percent atheroma volume (35.7 ​± ​8.6 vs. 38 ​± ​8.8%, p ​= ​0.004) and total atheroma volume (174.7 ​± ​80 vs. 190.9 ​± ​84 ​mm³, p ​= ​0.03) and less images with calcification (22.2 vs. 26.5%, p ​= ​0.025). The use of aspirin and statin prior to and during the trials was similar. The use of ACE inhibitors and beta blockers was lower in the no risk factor group prior to and during the trials. The change in percent atheroma volume (−0.2 ​± ​2.8 vs. −0.1 ​± ​3.6%, p ​= ​0.71), total atheroma volume (−5.5 ​± ​23.4 vs. −3.8 ​± ​22.7 ​mm³, p ​= ​0.42), and the percentage of patients demonstrating any degree of progression (50.9% vs 45.1%, p ​= ​0.20) were similar in those without and with standard modifiable risk factors, respectively.

Conclusion

Patients who develop clinical coronary atherosclerosis without standard modifiable risk factors have similar rates of plaque progression to those with traditional risk factors.

•

Outcome of patients with CAD despite no traditional risk factors is poorly understood.

•

Serial intravascular ultrasound studies provide an opportunity to examine this.

•

Patients without standard risk factors had lower plaque burden and calcification.

•

Use of aspirin and statin was similar in patients with and without standard risk factors.

•

Plaque progression was similar in those without and with standard risk factors.

When to use intravascular ultrasound or optical coherence tomography during percutaneous coronary intervention?

Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are intravascular imaging technologies widely used in the cardiac catheterization laboratory. The impact of these modalities for optimizing the acute and longer-term clinical impact following percutaneous coronary intervention (PCI) is supported by a wealth of clinical evidence. Intravascular imaging provides unique information for enhanced lesion preparation, optimal stent sizing, recognizing post PCI complications, and the etiology of stent failure. This review compares and contrasts the key aspects of these imaging modalities during PCI.

Fundamentals and role of intravascular ultrasound in percutaneous coronary intervention

Intravascular ultrasound (IVUS) is a catheter-based invasive imaging modality that has become an essential adjunctive tool to percutaneous coronary intervention (PCI) over the past 20 years. Clinical applications of IVUS in PCI include assessment of lesion severity, characterizing plaque morphology, optimization of acute stent results and clarification of mechanisms of stent failure. Numerous meta-analyses of large observational and randomized studies support the role of IVUS-guided PCI in reducing short and long-term adverse outcomes, including mortality and stent failure, particularly in patients receiving drug-eluting stents (DESs) and in complex lesion subsets. The current review provides a summary of the fundamental aspects and current clinical roles of IVUS in coronary intervention.

Comparison of Intravascular Ultrasound Virtual Histology Parameters in Diabetes versus Non-Diabetes with Acute Coronary Syndrome

INTRODUCTION

The progression and pattern of coronary atherosclerosis in diabetes mellitus (DM) is different from non-DM, leading to a higher rate of vascular complications in DM.

OBJECTIVE

This study aims to assess and compare the high-risk plaque characteristics in the culprit artery of DM and non-DM patients with acute coronary syndrome (ACS) using virtual histology intravascular ultrasound (VH-IVUS).

METHODS

A total of 158 ACS patients were included, 63 of whom were known to have DM. IVUS analysis was done in the de novo target vessel and culprit lesion for which percutaneous coronary intervention was planned. Culprit lesions with a visual-estimate angiographic stenosis of <70% were excluded.

RESULTS

The mean age of patients was 52.4 ± 11.6 years. The study group comprised 82% men, 31% with hypertension, and 39.87% with DM. No significant difference was observed between the DM and non-DM groups in relation to quantitative IVUS parameters like lesion length, minimal lumen area, and plaque area. However, there was a significant difference in VH-IVUS parameters like higher necrotic core and dense calcium in the DM patients than in the non-DM patients (p < 0.01). The occurrence of VH-derived thin-cap fibroatheroma (VH-TCFA) in the culprit vessel was significantly higher in the DM group than in the non-DM group (25.3 vs. 5.2%; p < 0.01). Positive vessel-wall remodeling was noted in both groups without any significant difference (p = 0.74).

CONCLUSION

The DM patients had high-risk plaque composition features like a higher necrotic core, which is a marker of plaque vulnerability. Thus, aggressive medical therapy targeting vascular inflammation using high-dose statins would help in the stabilization of unstable plaque morphology and the reduction of major cardiovascular events.

Imaging-guided PCI for event suppression in Japanese acute coronary syndrome patients: community-based observational cohort registry

Although there is accumulating evidence for the usefulness of imaging-guided percutaneous coronary intervention (PCI), there are few studies for acute coronary syndrome (ACS), and the impact of the frequency of use has not been well addressed. From the Kumamoto Intervention Conference Study; a Japanese registry comprising 17 institutions, consecutive patients undergoing successful PCI from April 2008 through March 2014 were enrolled. Subjects were divided into two groups: imaging-guided PCI and angiography-guided PCI. Clinical outcome was a composite of cardiac death, non-fatal myocardial infarction, and stent thrombosis within 1 year. A total of 6025 ACS patients were enrolled: 3613 and 2412 patients with imaging- and angiography-guided PCI, respectively. Adverse cardiac events were significantly lower in the imaging-guided PCI group (long-rank P < 0.001). Even after propensity-score matching, the event rates still showed significant differences between the two groups (log-rank P = 0.004). To assess the effects of frequency of imaging usage, we divided the 17 institutions into six low-, six moderate-, and five high-frequency groups. The event rates decreased depending on the frequency, seemingly driven by stepwise event suppression in angiography-guided PCI. In Japanese ACS patients, the incidence of adverse clinical events in patients treated with imaging-guided PCI were significantly lower than that in patients with angiography-guided PCI. Better clinical result was found in the institutions using intravascular imaging more frequently. University Hospital Medical Information Network (UMIN)-CTR (http://www.umin.ac.jp/ctr/). Identifier: KICS (UMIN000015397).

Intravascular ultrasound is a key diagnostic tool in subclavian vein varicosity

Varicose veins of the neck are far less common than lower extremity varicosities. Often, neck varicosities can be a sign of a more central venous obstruction. Here, we describe a patient with no risk factors for central venous obstruction who presented with a recurrent left subclavian vein (LSV) varicosity causing significant pain and discomfort that was recalcitrant to repeated phlebectomy. Venography revealed a dilated LSV with no significant venographic stenosis in the LSV or brachiocephalic vein. Intravascular ultrasound subsequently revealed a culprit hypertrophied valve that was successfully treated with valvuloplasty, resulting in durable resolution of the patient's symptoms, suggesting that intravascular ultrasound was essential in the diagnosis and treatment of this hypertrophied valve.

Optimal surface segmentation with convex priors in irregularly sampled space

Optimal surface segmentation is a state-of-the-art method used for segmentation of multiple globally optimal surfaces in volumetric datasets. The method is widely used in numerous medical image segmentation applications. However, nodes in the graph based optimal surface segmentation method typically encode uniformly distributed orthogonal voxels of the volume. Thus the segmentation cannot attain an accuracy greater than a single unit voxel, i.e. the distance between two adjoining nodes in graph space. Segmentation accuracy higher than a unit voxel is achievable by exploiting partial volume information in the voxels which shall result in non-equidistant spacing between adjoining graph nodes. This paper reports a generalized graph based multiple surface segmentation method with convex priors which can optimally segment the target surfaces in an irregularly sampled space. The proposed method allows non-equidistant spacing between the adjoining graph nodes to achieve subvoxel segmentation accuracy by utilizing the partial volume information in the voxels. The partial volume information in the voxels is exploited by computing a displacement field from the original volume data to identify the subvoxel-accurate centers within each voxel resulting in non-equidistant spacing between the adjoining graph nodes. The smoothness of each surface modeled as a convex constraint governs the connectivity and regularity of the surface. We employ an edge-based graph representation to incorporate the necessary constraints and the globally optimal solution is obtained by computing a minimum s-t cut. The proposed method was validated on 10 intravascular multi-frame ultrasound image datasets for subvoxel segmentation accuracy. In all cases, the approach yielded highly accurate results. Our approach can be readily extended to higher-dimensional segmentations.

Intravascular evaluation of coronary atherosclerotic lesions among Egyptian diabetic patients with acute coronary syndromes

Background

Coronary artery disease is one of the main causes of death in diabetes mellitus (DM). Egypt was listed among the world top 10 countries regarding the number of diabetic patients by the International Diabetes Federation (IDF).

Aim of work

Assessment of the extent of coronary atherosclerotic disease and lesion tissue characterization among diabetic compared to non-diabetic Egyptian patients.

Methodology

IVUS studies of 272 coronary lesions in 116 patients presented with unstable angina were examined. The patients were divided into two groups: diabetic group (50 patients with 117 lesions) and non-diabetic group (66 patients with 155 lesions).

Results

As compared to the non-diabetic group, the diabetic patients were more dyslipidemic (84% vs 39.4%, p = 0.001) with higher total cholesterol level (194.6 ± 35.3 vs 174.4 ± 28.5 mg/dl, p = 0.001) and higher LDL-C (145.3 ± 27.1 vs 123.2 ± 31.4, p = 0.001). Regarding lesions characteristics, the diabetic group had longer lesions (19.4 ± 7.4 vs 16.3 ± 7.9 mm, p = 0.002) with higher plaque burden (60.8 ± 15.3 vs 54.8 ± 14.0, p 0.002) and more area stenosis percentage (60.8 ± 15.6 vs 55.6 ± 14.1, p = 0.008). Structurally, the diabetic group lesions had more lipid content (19.8 ± 8.8 vs 16.8 ± 8.7, p = 0.008) and more necrotic core (17.6 ± 7.4 vs 14.7 ± 4.8, p = 0.008) but less calcification (6.9 ± 3.6 vs 11.8 ± 6.3, p = 0.001). The RI was negative in both groups, 0.95 ± 0.13 in the diabetic group vs 0.98 ± 0.19 in non-diabetic group (p = 0.5). Within the diabetic group lesions, the dyslipidaemic subgroup had more lipid content (23. ± 5.2 vs 14.6 ± 8.6, p = 0.01) but less fibrotic component (48.6 ± 4.7 vs 59.1 ± 13.6%, p = 0.01) and less calcification (10.9 ± 6.8% vs 14.07 ± 3.8%, p = 0.02) as compared to the nondyslipidaemic subgroup.

Conclusions

Diabetic patients with coronary atherosclerosis in Egypt have longer lesions with higher plaque burden and more percent area stenosis with negative remodeling index. The diabetic lesions had more lipid content and more necrotic core but less calcification.

Hemodynamic changes lead to alterations in aortic diameters and may challenge further stent graft sizing in acute aortic syndrome

Background

Precise stent graft sizing in Thoracic endovascular aortic repair (TEVAR) is crucial to receive optimal long-term results. Computed tomography (CT), as the current standard in assessing aortic diameters (ADs), is often performed at initial diagnosis. Since several acute aortic diseases are associated with blood loss and/or volume re-distribution, assessed AD might be influenced by impaired hemodynamic conditions. Intravascular ultrasound (IVUS) offers real-time assessment, especially after hemodynamic restoration, and might help for stent graft choice.

Methods

We investigated the correlation between CT and later IVUS measurements in elective (n=83) and emergency patients (n=32) at the level distal to the left subclavian artery (LSA), a frequent proximal landing zone in TEVAR. Patients were grouped depending on their shock index (heart rate/systolic blood pressure): emergency patients with diagnosis of acute aortic syndrome, urgently required treatment after admission and had a shock index >1, otherwise were grouped as elective. Basic hemodynamics were assessed for both groups at admission and at definite IVUS-procedure.

Results

At time of admission the emergency group showed lower blood pressure (99±19.8 vs. 141±24 mmHg; P=0.001) and higher heart rate (98±13 vs. 70±12 bpm; P=0.001) compared to elective patients. By hemodynamic stabilization comparable blood pressure and heart rate were achieved in both groups at time of IVUS. In the emergency group, we found a significantly increase in AD after hemodynamic stabilization, whereas the diameters did not change in the elective group (IVUS_meanvs. CT_mean: 5.1±1.0 vs. 0.4±2.2 mm; P=0.001 and IVUS_minvs. CT_mean: 3.9±1.3 vs. -0.3±2.2 mm; P=0.011).

Conclusions

IVUS for stent graft sizing is a valuable approach during TEVAR, especially in the light of emergency treatment by offering real-time assistance. Impaired hemodynamic conditions might lead to relevant changes in AD and may strongly influence stent graft choice. In these cases, careful stent graft selection might contribute to avoidance of stent graft related complication.

[Contribution of intracoronary imaging in acute coronary syndrome]

Acute coronary syndrome (ACS) remains a major cause of mortality and morbidity in the world, although it has considerably decreased through technical and pharmacological advances. The physiopathological approach of the ACS has progressed considerably in recent years thanks to the anatomopathological work and the data of the endocoronary imaging, in particular of the endovascular ultrasound (IVUS). Plaque rupture is the most common cause of ACS, however OCT (optical coherence tomography) studies have shown that surface plaque erosion was more common than thought. The use of OCT in the ACS may prove to be a valuable diagnostic aid: study of the culpable lesion, spontaneous coronary dissection or intramural spontaneous hematoma, stent thrombosis; from a therapeutic point of view: reduction of the risk of stent malapposition, additional technique, delayed stenting, implantation of a bioresorbable stent, medical treatment of ACS without stenting. Endocoronary imaging, especially OCT, will of course never be systematic as treatment of ACS, but providing excellent value for both diagnosis and treatment, it must be an integral part of the therapeutic arsenal available in cathlab.

Stent boost enhancement compared to intravascular ultrasound in the evaluation of stent expansion in elective percutaneous coronary interventions

Background

Stent underexpansion is a major risk factor for in-stent restenosis and acute in-stent thrombosis¹Intravascular ultrasound (IVUS) is one of the standards for detection of stent underexpansion (de Feyter et al. 1999; Mintz et al., 2001). StentBoost (SB) enhancement allows an improved angiographic visualization of the stent (Koolen et al., 2005).

Aim of work

Comparison of stent expansion by IVUS and SB enhancement and detection of value of SB to guide dilatation post stent deployment.

Methodology

IVUS, SB enhancement and QCA were done in 30 patients admitted for elective stenting procedures .We compared measurements of mean ±standard deviations of (Max SD, Min SD, Mean SD, stent symmetry index) using IVUS, SB and QCA after stent deployment and after postdilatation whenever necessary to optimize stent deployment. The Stent symmetry index was calculated [(maximum stent diameter minus minimum stent diameter) divided by maximum stent diameter].

Results

The Max SD was (3.45 ± 0.62 vs 3.55 ± 0.56 vs 2.97 ± 0.59) by IVUS vs SB vs QCA respectively. Max SD was significantly higher by IVUS vs QCA (p .009) and between SB vs QCA (p .001) while there was nonsignificant difference between IVUS vs SB (p .53). The Min SD was (2.77 ± 0.53 vs 2.58 ± 0.56 vs 1.88 ± 0.60) by IVUS vs SB vs QCA respectively. Min SD was significantly higher by IVUS vs QCA (p .001) and between SB vs QCA (p .001) while there was nonsignificant difference between IVUS vs SB (p .07). The stent symmetry index was (0.24 ±0.09 vs 0.34 ± 0.09 vs 0.14 ±0.27) by IVUS vs SB vs QCA respectively. It was significantly higher by IVUS vs QCA (p .001) and between SB vs QCA (p .001) while there was nonsignificant difference between IVUS vs SB (p .32). SB was positively correlated with IVUS measurements of Max SD (p < .0001 & r 0.74) and Min SD (p < .0001 & r 0.68). QCA was positively correlated with IVUS measurements of Max SD correlation (p < .0001 & r 0.69) and Min SD (p < .0001 & r 0.63). QCA was positively correlated with SB measurements of Max SD (p < .0001 & r 0.61) and Min SD (p .003 & r 0.49).

Conclusions

StentBoost enhancement has superior correlations for stent expansion measured by IVUS when compared with QCA. SB enhancement improved stent visualization and identification of stent underexpansion to guide stent postdilatation.

Intermediate analysis of magnesium alloy covered stent for a lateral aneurysm model in the rabbit common carotid artery

OBJECTIVE

To analyze the outcomes of a magnesium alloy covered stent (MACS) for a lateral aneurysm model in common carotid artery (CCA).

METHODS

In 32 rabbits, a MACS (group A, n = 17) or a Willis covered stent (WCS; group B, n = 15) was inserted and the rabbits were sacrificed 1, 3, 6, or 12 months after stenting. Angiography and intravascular ultrasound (IVUS) were performed at 3, 6, and 12 months. Scanning electron microscopy was performed for six stents in each group at 1, 3, and 6 months, and histopathology and histomorphology were conducted at 3 (n = 4), 6 (n = 4), and 12 (n = 12) months.

RESULTS

Final angiography showed complete occlusion of the aneurysms in 12 cases. IVUS at 6 and 12 months revealed a significant increase in mean lumen area of the stented CCA in group A and also showed greater mean lumen area in group A than in group B. The endothelialization process was quicker in group A than in group B.

CONCLUSION

MACS is effective for occlusion of lateral aneurysms and is superior to WCS in growth of the stented CCA and endothelialization. Further work is needed to make this device available for human use.

KEY POINTS

• The MACS is an effective approach for occlusion of a lateral aneurysm. • IVUS showed that the CCA could grow following degradation of the MACS. • The lumen area of the stented CCA was excellent in MACS. • HE staining displayed the degradation of the magnesium alloy stent. • Combination of IVUS and DSA were applied in this study.

[Subintimal recanalization. Indications, technique and results]

CLINICAL/METHODICAL ISSUE

This article gives an overview of the current importance of so-called subintimal recanalization in the lower extremities.

STANDARD RADIOLOGICAL METHODS

The primary technical goal of endovascular interventions in the lower extremities is the endoluminal restoration of blood circulation from the iliac arteries into the feet.

METHODICAL INNOVATIONS

If endoluminal recanalization of e.g. high-grade flow-relevant stenoses or chronic total occlusion (CTO) is technically not possible, subintimal recanalization is a promising option and the only remaining minimally invasive alternative. During subintimal recanalization a channel is intentionally generated in the vessel wall (dissection) in order to bypass e. g. a chronic vascular occlusion over as short a distance as possible.

PERFORMANCE

The technical success rate for subintimal recanalization of CTO of the lower extremities is 65-100 %. Technical failure occurs in approximately 25 % using the catheter and wire technique and is caused in most cases by difficulties in reaching the true lumen after the subintimal passage (the so-called re-entry).

ACHIEVEMENTS

Compared to conventional subintimal recanalization, in recent years so-called re-entry devices have expanded the technical possibilities and depending on the medical experience and training level of the physician, provide an improvement in the technical success rate, a lower complication rate, a reduction of fluoroscopy time and the amount of necessary contrast medium but also result in higher costs.

PRACTICAL RECOMMENDATIONS

Subintimal recanalization, whether carried out conventionally with a catheter and wire or using re-entry devices, of high-grade stenoses or CTO in the lower extremities provides a high technical success rate but requires an experienced and trained physician who is capable of operating the elaborate materials and mastering any possible complications.

Recanalized chronic coronary thrombus: unraveling a hazy coronary lesion by intravascular ultrasound

Hazy lesions in coronary angiography can often be a puzzle for the interventional cardiologist. Recanalized chronic coronary thrombus, although rare, is one of the potential diagnoses. Intracoronary imaging with intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are tools that can guide to the correct diagnosis. We present the images of a case where IVUS was used to unravel such a lesion.

Left Main Coronary Artery Stenting to Relieve Extrinsic Compression by a Giant Pulmonary Artery Aneurysm in a Patient with Idiopathic Pulmonary Artery Hypertension

Pulmonary artery aneurysm (PAA) is a rare but lethal disease. We present a female patient with idiopathic pulmonary artery hypertension (IPAH)-related PAA, who suffered from unstable angina pectoris. Multi-detector computed tomography and coronary angiogram revealed extrinsic compression of the left main coronary artery (LMCA) caused by a giant PAA with severe ostial stenosis. Intravascular ultrasound showed an oval-shaped ostium of the LMCA, indicating extrinsic compression. After successful LMCA stent implantation, chest pain was greatly relieved. This case illustrates that beyond right ventricle ischaemia and coronary atherosclerotic disease, LMCA compression by PAA should be considered in the differential diagnosis of angina in patients with IPAH related PAA. In addition, intravascular ultrasound can be used to confirm the diagnosis and guide the stent implantation safely.

A case of percutaneous coronary intervention for treatment of iatrogenic chronic total occlusion of the left circumflex artery after mitral valve repair

A 55-year-old man had undergone mitral annuloplasty for mitral regurgitation with posterior mitral prolapse 3 years prior. He was examined at our hospital for dyspnea and fatigue. A coronary angiogram revealed iatrogenic chronic total occlusion (CTO) in the left circumflex coronary artery. We performed percutaneous coronary intervention (PCI) and successfully placed an everolimus-eluting stent. An intravascular ultrasound (IVUS) showed an impaired coronary artery at the occlusion site. To our knowledge, this is the first reported successful PCI for iatrogenic CTO after mitral valve repair. IVUS-guided PCI may help prevent complications in unusual CTO cases, such as coronary rupture.

Bioresorbable vascular scaffold (BVS) for in-stent chronic total occlusion: Antegrade recanalization and IVUS-guided BVS implantation by radial access

The completely absorbable stents represent one of the latest innovations in the field of interventional cardiology, prospecting the possibility of "vascular repair". In the published trials (ABSORB Cohort A and B, ABSORB EXTEND, and ABSORB II, III and IV) chronic total occlusions (CTOs) were considered an exclusion criteria. More recently the CTO-ABSORB pilot study demonstrated the safety and feasibility of bioresorbable vascular scaffold (BVS) use in case of CTO recanalization. We present the first case, to our knowledge, of in-stent occlusion successfully treated with an everolimus-eluting BVS and discuss its potential advantages in such kind of lesions.

Inflammation, plaque progression and vulnerability: evidence from intravascular ultrasound imaging

Increasing evidence points to a critical role of inflammation in the development and propagation of atherosclerotic cardiovascular disease. Pathological studies in human and animal models have elucidated specific inflammatory mediators contributing to the progression and rupture of atherosclerotic plaque in the artery wall. These observations not only outline the importance of inflammation in atheroma progression but also the potential of anti-inflammatory therapeutic approaches to prevent and stabilize atherosclerotic disease. Intravascular ultrasonography enables direct atheroma visualization in vivo. Additionally, refinements in ultrasound technology permitting radiofrequency backscatter analysis enhance plaque characterization associated with disease instability. These imaging modalities will continue to provide opportunities for evaluating novel inflammatory mechanisms and anti-inflammatory therapies.

Intravascular Ultrasound Versus Optical Coherence Tomography for Coronary Artery Imaging - Apples and Oranges?

Intravascular imaging has advanced our understanding of coronary artery disease and facilitated decision-making in percutaneous coronary intervention (PCI). In particular, intravascular ultrasound (IVUS) has contributed significantly to modern PCI techniques. The recent introduction of optical coherence tomography (OCT) has further expanded this field due to its higher resolution and rapid image acquisition as compared with IVUS. Furthermore, OCT allows detailed planning of interventional strategies and optimisation before stent deployment, particularly with complex lesions. However, to date it is unclear whether OCT is superior to IVUS as an intracoronary imaging modality with limited data supporting OCT use in routine clinical practice. This review aims to compare these two intracoronary imaging techniques and the recent evidence for their use in this ever-changing field within interventional cardiology.

Long-term endothelin receptor antagonism attenuates coronary plaque progression in patients with early atherosclerosis

AIM

The purpose of the current study was to determine if long term treatment with an endothelin-A (ETA) receptor antagonist attenuates the progression of coronary plaques in patients with coronary endothelial dysfunction.

METHODS

Thirty-five patients with non-obstructive coronary disease and coronary endothelial dysfunction were randomized in a double blind manner to treatment with placebo or ETA receptor antagonist Atrasentan (10 mg) for six months. Endothelial function was assessed by the change in coronary blood flow and coronary artery diameter in response to intracoronary acetylcholine. Normalized mean total atheroma volume (TAVMEAN), percent atheroma volume (PAV) and changes of atheroma volume were assessed by intravascular ultrasound (IVUS) at baseline and 6-month follow-up.

RESULTS

In segments with coronary endothelial dysfunction, there was a significant decrease in normalized TAVMEAN and PAV at six months from baseline in the Atrasentan group compared to the placebo group median (IQR) -2.00 mm(3) (-7.28, 2.53.) vs 9.11 mm(3) (1.23, 14.05), p=0.0024 and 0.955% (-3.43, 1.70) vs 3.85% (-0.39, 14.59) p=0.010. There was no change in normalized TAV or PAV in the segments with normal endothelial function.

CONCLUSION

This study demonstrates that 6-month treatment with Atrasentan attenuates progression of coronary plaque in segments with endothelial dysfunction.