Detection of Unstable Plaques in Patients with Carotid Stenosis using B-Mode Ultrasonography

Perioperative point-of-care ultrasound for diagnosis of acute lower extremity arterial thrombosis after total hip arthroplasty revision: a case report

PURPOSE

Acute arterial thrombosis after hip arthroplasty is a rare event associated with potentially catastrophic complications. Early clinical diagnosis of progressive limb ischemia is often difficult in the immediate postoperative period because of residual neuraxial blockade and the nonspecific nature of signs. We describe the use of point-of-care ultrasound (POCUS) in the postanesthesia care unit (PACU) to diagnose this complication early and facilitate timely intervention.

CLINICAL FEATURES

A 78-yr-old female patient underwent elective right hip revision arthroplasty under spinal anesthesia and postoperatively had an absent dorsalis pedis pulse on her operative leg as screened by an audible-only Doppler. No obvious clinical symptoms were present as the patient was still under subarachnoidal blockade. A bedside POCUS vascular evaluation was performed in the PACU and showed an absence of blood flow in the superficial femoral artery, expediting the confirmation of a surgical emergency. The patient underwent a successful open thrombectomy and made an uneventful postoperative recovery.

CONCLUSION

Our case report highlights the novel use and impact of bedside POCUS to assess the presence or absence of distal limb arterial blood flow and, in this case, the level of arterial occlusion.

Overlapping Genetic Background of Coronary Artery and Carotid/Femoral Atherosclerotic Calcification

Background and objectives: Multivessel atherosclerosis and its genetic background are under-investigated, although atherosclerosis is seldom local and still causes high mortality. Alternative methods to assess coronary calcification (CAC) might incorporate genetic links between different arteries’ atherosclerotic involvement, however, co-occurrences of coronary calcification have not been investigated in twins yet. Materials and Methods: We assessed the heritability of radio morphologically distinct atherosclerotic plaque types in coronary (non-enhanced CT, Agatston score), carotid, and femoral arteries (B-mode ultrasound) in 190 twin subjects (60 monozygotic, 35 dizygotic pairs). Four-segment scores were derived in order to assess the dissemination of the distinct plaque types in the carotid and femoral arteries taking bilaterality into account. We calculated the genetic correlation between phenotypically correlating plaque types in these arteries. Results: CAC and dissemination of calcified plaques in the carotid and femoral arteries (4S_hyper) were moderately heritable (0.67 [95% CI: 0.37–1] and 0.69 [95% CI: 0.38–1], respectively) when adjusted for age and sex. Hypoechoic plaques in the carotid and femoral arteries showed no heritability, while mixed plaques showed intermediate heritability (0.50 [95% CI: 0–0.76]). Age and sex-adjusted phenotypic correlation between CAC and 4segm_hyper was 0.48 [95% CI: 0.30–0.63] and the underlying genetic correlation was 0.86 [95% CI: 0.42–1]. Conclusions: Calcification of atherosclerotic plaques is moderately heritable in all investigated arteries and significant overlapping genetic factors can be attributed to the phenotypical resemblance of coronary and carotid or femoral atherosclerotic calcification. Our findings support the idea of screening extracoronary arteries in asymptomatic individuals. We also propose a hypothesis about primarily carotid-coronary and femoral-coronary atherosclerosis as two distinct genetic predispositions to co-localization.

Duplex ultrasound findings and clinical outcomes of carotid restenosis after carotid endarterectomy

This study aimed to describe the duplex ultrasound (DUS) findings associated with carotid restenosis after carotid endarterectomy (CEA) and to determine whether carotid restenosis is associated with the clinical outcomes of CEA. Between January 2007 and December 2016, a total of 660 consecutive patients who underwent 717 CEAs were followed up at our hospital with DUS surveillance for at least 3 years after CEA. These patients were analyzed retrospectively for this study. Following CEA, restenosis was defined as the development of ≥50% stenosis, diagnosed on the basis of DUS findings of the luminal narrowing and velocity criteria. The study outcomes were defined as restenosis of the ipsilateral carotid artery after CEA and late (>30days) fatal or nonfatal stroke ipsilateral to the carotid restenosis. During the median follow-up period of 74 months, the restenosis incidence was 2.8% (20/717), and there were 2 strokes (2/20, 10%) ipsilateral to the restenosis after CEA; reintervention was performed for 11 patients with carotid restenosis (55%). Within 2 years after CEA, restenosis was identified in 9 cases (45%, 9/20), and 8 reinterventions (72.7%, 8/11) were performed. According to DUS findings, the morphologic characteristics of carotid restenosis were different from the preoperative plaque morphology. Among the 20 carotid restenosis cases, we observed the following DUS patterns: homogenous isoechoic restenosis (n = 14, 70%), homogenous hypoechoic (n = 2, 10%), isoechoic with hypoechoic surface (n = 3, 15%), and hypoechoic with isoechoic surface (n = 1, 5%). Although 9 carotid restenosis patients received prophylactic reintervention to mitigate the progression of restenosis, the 2 symptomatic restenosis patients had isoechoic lesions with hypoechoic surfaces on DUS. On Kaplan-Meier survival analyses, in terms of stroke-free survival rates, there was a higher risk of stroke among patients with carotid restenosis compared with patients without restenosis, with a non-significant trend (P = 0.051). In conclusion, most carotid restenoses were identified within 2 years after CEA, and there was a non-significant trend toward a higher risk of stroke among patients with carotid restenosis.

Rare Case of Floating Intimal Flap Associated with Atheromatous Carotid Plaque

BACKGROUND

A mobile carotid plaque can be detected by duplex ultrasonography and is a high-risk factor for embolic stroke.

CASE DESCRIPTION

We herein present a case involving an 80-year-old man with an asymptomatic carotid floating flap diagnosed by duplex ultrasonography and treated with carotid endarterectomy. Intraoperatively, an ulceration was found immediately proximal to the neck of the floating flap, and the shape and size of the ulceration were quite similar to those of the floating flap. In a histopathologic examination of the specimen resected by carotid endarterectomy, the plaque lacked the internal elastic lamina (IEL) at the ulceration, calcification was observed in the plaque and medial layer at the ulceration, and the floating flap consisted of the IEL accompanied by calcification, fibrin, and foamy cells.

CONCLUSIONS

Progression of the atheroma and Mönckeberg sclerosis might have affected disruption of the IEL, causing the IEL to finally peel off. A floating intimal flap accompanied by an atheroma without intraplaque hemorrhage is a rare cause of mobile plaque formation. This type of mobile plaque might not be dissolved by medical treatment alone. In such cases, surgical treatment is a suitable therapeutic choice to prevent stroke.

Loss of SPRR3 in ApoE-/- mice leads to atheroma vulnerability through Akt dependent and independent effects in VSMCs

Vascular smooth muscle cells (VSMCs) represent important modulators of plaque stability in advanced lesions. We previously reported that loss of small proline-rich repeat protein 3 (Sprr3), leads to VSMC apoptosis in a PI3K/Akt-dependent manner and accelerates lesion progression. Here, we investigated the role of Sprr3 in modulating plaque stability in hyperlipidemic ApoE^-/- mice. We show that loss of Sprr3 increased necrotic core size and reduced cap collagen content of atheromas in brachiocephalic arteries with evidence of plaque rupture and development of intraluminal thrombi. Moreover, Sprr3^-/-ApoE^-/- mice developed advanced coronary artery lesions accompanied by intraplaque hemorrhage and left ventricle microinfarcts. SPRR3 is known to reduce VSMC survival in lesions by promoting their apoptosis. In addition, we demonstrated that Sprr3^-/- VSMCs displayed reduced expression of procollagen in a PI3K/Akt dependent manner. SPRR3 loss also increased MMP gelatinase activity in lesions, and increased MMP2 expression, migration and contraction of VSMCs independently of PI3K/Akt. Consequently, Sprr3 represents the first described VSMC modulator of each of the critical features of cap stability, including VSMC numbers, collagen type I synthesis, and protease activity through Akt dependent and independent pathways.

Sonographic evaluation of atherosclerosis burden in carotid arteries of ischemic stroke patients and its relation to paraoxonase 1 and 2, MTHFR and AT1R genetic variants

OBJECTIVE

Common variants of the Paraoxonase (PON), 5-Methyl-Tetrahydrofolate-Reductase (MTHFR) and Angiotensin-II receptor 1 (AT1R) genes have been associated with ischemic stroke (IS) risk. Moreover, carotid atherosclerosis is a common cause of IS. The aim of this study is to explore whether variants in these genes associate with the severity of ultrasonographic determined atherosclerosis assessed in carotid arteries.

PATIENTS AND METHODS

Etiologic subtype of cerebral ischemia was determined according to the TOAST classification. Genotypes were detected by PCR and restriction analysis. An ultrasonographic supra-aortic trunks study was performed to all patients to assess their atherosclerotic involvement based on predefined criteria.

RESULTS

In IS patients, none of the analyzed gene distributions differed concerning the stenosis degree. Nevertheless, a trend was observed for the rs662 and rs7493 variants of the PON1 and PON2 genes respectively. When evaluated the results based on different inheritance models, a significant contribution of rs7493 variant according to a dominant (OR=2.397, 95% CI (1.001-5.376); p=0.045) and log-additive inheritance forms (OR=1.85, 95% CI (1.07-3.2); p=0.03) was observed. Only rs7493 reached statistical significance (p=0.013), when genotype distribution was analyzed according to carotid intima-media thickness (cIMT) and remain significant in multivariate logistic regression analysis (OR=2.66, 95% CI (1.1 to 6.4); p=0.03).

CONCLUSION

In IS patients of the north area of the Gran Canaria island the PON2 (rs7493) gene variant associates with a worse ultrasonographic profile. Conversely, the Cys311Cys homozygosis of the rs7493 variant was also related to a better ultrasonographic profile in our study.

Nε-(carboxymethyl)lysine Concentration in Debris from Carotid Artery Stenting Correlates Independently with Signal Intensity on T1-Weighted Black-Blood Magnetic Resonance Images

BACKGROUND AND PURPOSE

Because magnetic resonance imaging (MRI) focuses on the morphological characteristics of carotid artery plaques, its diagnostic value with respect to plaque vulnerability is limited. We examined the correlation between N^ε-(carboxymethyl)lysine (CML), a main chemical structure of advanced glycation end-products, and the vulnerability of plaques visualized on MRI scans.

MATERIALS AND METHODS

We enrolled 43 patients who had undergone carotid artery stenting (CAS) for carotid artery stenosis; all underwent MRI studies, including black-blood MRI and diffusion-weighted imaging (DWI). The signal intensity ratio (SIR) of plaques to adjacent sternocleidomastoid muscle (P/M) on T1- and T2-weighted images (T1WI, T2WI) was calculated. Protein samples were extracted from debris trapped by a filter device. The concentrations of CML and myeloperoxidase (MPO) were measured by solid-phase enzyme-linked immunosorbent assay.

RESULTS

The patients were classified into 2 groups based on their SIR-P/M on T1WI and T2WI scans. We observed a higher incidence of post-CAS DWI lesions in patients with a higher than a lower SIR-P/M on T1WI; the CML and MPO concentrations in their CAS debris were also higher. No such differences were seen in patients with a higher or lower SIR-P/M on T2WI scans. The concentration of CML in CAS debris correlated independently with the SIR-P/M on T1WI of the carotid plaques, and was related to the concentration of MPO in CAS debris.

CONCLUSIONS

Our findings suggest CML as a candidate molecular imaging probe for the identification of vulnerable plaques.

Genetic variants of PTGS2, TXA2R and TXAS1 are associated with carotid plaque vulnerability, platelet activation and TXA2 levels in ischemic stroke patients

Eicosanoids may play a role in ischemic stroke. However, the associations of variants in cyclooxygenase (COX) pathway genes and interaction among these variants with carotid plaque vulnerability are not fully understood. In present study, twelve variants in COX pathway genes were examined using matrix-assisted laser desorption ionization time-of-flight mass spectrometry method in 396 patients with ischemic stroke and 291 controls. Platelet aggregation, platelet-leukocyte aggregates, and urine 11-dehydrothromboxane B2 (11-dTxB2) were also measured. According to the results of carotid high-resolution B-mode ultrasound, the patients were stratified into the following groups [i.e., non-carotid plaque and carotid plaque. The carotid plaque was further classified into subgroups of echolucent plaque (ELP) and echogenic plaque (EGP)]. Additionally, gene-gene interactions were analyzed to assess whether there was any interactive role for assessed variants in affecting carotid plaque vulnerability, platelet activation and 11-dTxB2 levels. There were no significant differences in the frequencies of genotypes of the twelve variants between patients and controls. Among 396 patients, 294 cases (74.2%) had carotid plaques (106 had ELP, 188 had EGP). Frequency of PTGS2 rs20417CC, TXAS1 rs2267679TT, TXAS1 rs41708TT, PTGIS rs5602CC, and TXA2R rs1131882TT genotype was significantly higher in patients with plaque compared with patients without plaque, or in patients with ELP compared with patients with EGP. 11-dTxB2 levels, platelet aggregation and platelet-leukocyte aggregates were significantly higher in patients with ELP compared with patients without plaque or with EGP. Multivariate logistic regression analysis revealed that PTGS2 rs20417CC, TXA2R rs1131882TT, and high-risk interaction among variants in PTGS2 rs20417, TXA2R rs1131882 and TXAS1 rs41708 were independently associated with the risk of ELP after adjusting for confounding variables. The variants in COX pathway genes and the high-risk interactions among variants in PTGS2 rs20417, TXA2R rs1131882 and TXAS1 rs41708 were associated with high 11-dTxB2 and platelet activation, and independently associated with the risk of carotid plaque vulnerability. These variants might be potential markers for plaque instability.

Rationale, Design, and Methodological Aspects of the BUDAPEST-GLOBAL Study (Burden of Atherosclerotic Plaques Study in Twins-Genetic Loci and the Burden of Atherosclerotic Lesions)

The heritability of coronary atherosclerotic plaque burden, coronary geometry, and phenotypes associated with increased cardiometabolic risk are largely unknown. The primary aim of the Burden of Atherosclerotic Plaques Study in Twins-Genetic Loci and the Burden of Atherosclerotic Lesions (BUDAPEST-GLOBAL) study is to evaluate the influence of genetic and environmental factors on the burden of coronary artery disease. By design this is a prospective, single-center, classical twin study. In total, 202 twins (61 monozygotic pairs, 40 dizygotic same-sex pairs) were enrolled from the Hungarian Twin Registry database. All twins underwent non-contrast-enhanced computed tomography (CT) for the detection and quantification of coronary artery calcium and for the measurement of epicardial fat volumes. In addition, a single non-contrast-enhanced image slice was acquired at the level of L3-L4 to assess abdominal fat distribution. Coronary CT angiography was used for the detection and quantification of plaque, stenosis, and overall coronary artery disease burden. For the primary analysis, we will assess the presence and volume of atherosclerotic plaques. Furthermore, the 3-dimensional coronary geometry will be assessed based on the coronary CT angiography datasets. Additional phenotypic analyses will include per-patient epicardial and abdominal fat quantity measurements. Measurements obtained from monozygotic and dizygotic twin pairs will be compared to evaluate the genetic or environmental effects of the given phenotype. The BUDAPEST-GLOBAL study provides a unique framework to shed some light on the genetic and environmental influences of cardiometabolic disorders.

Evaluation and management of plaque protrusion or thrombus following carotid artery stenting

Carotid artery stenting (CAS) has become a common treatment for carotid artery stenosis. However, complications, such as an ischemic event, can occur with CAS during intra- and post-operative periods. Among these ischemic complications, plaque protrusion into the stent and thrombus on the stent have occurred after CAS. We retrospectively evaluated the temporal profile and treatment options for these complications in 32 consecutive cases who underwent CAS at our hospital between April 2009 and December 2011. The cases were evaluated pre-operatively for risk factors, as well as the plaque morphology and characteristics using computed tomographic angiography (CTA), ultrasound (US), and magnetic resonance imaging (MRI). Post-operatively, lesions were examined by CTA and/or US within 1 week of CAS. As a result, among the 32 cases, 8 experienced plaque protrusions or thrombus, which were treated with medication (anti-platelet and/or anti-coagulation reinforcement). In 7 of these 8 cases, the plaque protrusion or thrombus was stabilized with medication alone. However, the remaining case showed growth and migration of the plaque protrusion or thrombus when treated with medication alone, and therefore, required further endovascular treatment. We identified that a history of symptomatic cerebral infarction and plaques with ulceration were risk factors for plaque protrusion or thrombus formation after CAS, and pre dilatation can decrease the risk of these complications. Medication was effective in most cases of plaque protrusion or thrombus; however, further endovascular treatment was required when medication alone was unsuccessful.

Evidence for a strong genetic influence on carotid plaque characteristics: an international twin study

BACKGROUND AND PURPOSE

Few family studies reported moderate genetic impact on the presence and scores of carotid plaques. However, the heritability of carotid plaque characteristics remains still unclear. Twin studies more reliably estimate the relative contribution of genes to these traits in contrast to family study design.

METHODS

One hundred ninety-two monozygotic and 83 dizygotic adult twin pairs (age 49±15 years) from Italy, Hungary, and the United States underwent B-mode and color Doppler ultrasound of bilateral common, internal, and external carotid arteries.

RESULTS

Age-, sex-, and country-adjusted heritability was 78% for the presence of carotid plaque (95% CI, 55%-90%), 74% for plaque echogenicity (hypoechoic, hyperechoic, or mixed; 95% CI, 38%-87%), 69% for plaque size (area in mm2 in longitudinal plane; <or>50 percentile; 95% CI, 16%-86%), 74% for plaque sidedness (unilateral or bilateral; 95% CI, 25%-90%), 74% for plaque numerosity (95% CI, 26%-86%), 68% (95% CI, 40%-84%), and 66% (95% CI, 32%-90%) for the presence of plaque in carotid bulbs and proximal internal carotid arteries. No role of shared environmental factors was found. Unique environmental factors were responsible for the remaining variance (22%-34%). Controlling for relevant covariates did not change the results significantly.

CONCLUSIONS

The heritability of ultrasound characteristics of carotid plaque is high. Unshared environmental effects account for a modest portion of the variance. Our findings should stimulate the search for genes responsible for these traits.

Acoustic radiation force impulse imaging of the mechanical properties of arteries: in vivo and ex vivo results

We present results of a pilot study of ex vivo and in vivo acoustic radiation force impulse (ARFI) imaging demonstrating measurements of the mechanical properties of the carotid and popliteal arteries. The results were obtained on a modified commercial scanner, providing coregistered B-mode and color Doppler images. 2D and 1D through time images are formed from the measurements of tissues' response to very brief and localized applications of radiation force. The images show good correlation with B-mode and, in ex vivo studies, pathology-based characterizations of vessel geometry and plaque stiffness. In vivo measurements of arterial response during both systole and diastole are presented. We address implementation issues and discuss potential applications of this new vascular imaging method.