Small Distal Arteries Research Articles

Treatment-Related Reversible Cerebral Vasoconstriction Syndrome

Reversible cerebral vasoconstriction syndrome (RCVS) is a rare but significant cause of intracranial arteriopathy and stroke in young adults. The syndrome encompasses a spectrum of disorders radiologically characterized by reversible narrowing and dilation of intracranial arteries, often triggered by vasoactive drugs or the postpartum period. The hallmark clinical feature of RCVS is thunderclap headache with or without other neurological signs. Though endothelial dysfunction and sympathetic hyperactivation are hypothesized to be key mechanisms, the exact pathogenesis of RCVS is still unclear. RCVS’s diagnosis could be challenging, since vasospasm proceeds centripetally, initially involving distal small pial and cortical arteries, and angiographic studies, especially brain magnetic resonance angiography (MRA) and computed tomography angiography (CTA), may miss it in the early phase of the disease, while early signs such as vascular hyperintensities may be visible on T2/FLAIR sequences before vasospasm onset. Catheter angiography is the gold standard and it could be used to assess vasospasm reversibility post-intra-arterial vasodilator administration. Treatment is mainly symptomatic, and nimodipine is the most commonly administered therapy, given orally or intra-arterially in severe cases. Since many aspects of RCVS remain partially known, further research is needed to better understand the complex pathophysiology of this unique clinical condition and to optimize specific management strategies.

Comparison of radial artery occlusion between traditional radial access and distal radial access for coronary angiography and intervention: A prospective cohort study

BackgroundThe radial approach is now recommended as the default strategy in diagnostic coronary angiography and percutaneous coronary intervention. Radial artery occlusion (RAO) is the most common complication that limits subsequent angiographic procedures through this access. Recently, distal radial access (DRA) has been recommended as an alternative access site. Despite lower RAO rates in DRA in some recent clinical trials, concerns remain regarding possible complications and limitations due to the small size of the distal radial artery. ObjectiveThe present study aimed to compare traditional radial access (TRA) and DRA concerning RAO in percutaneous coronary procedures. MethodsIn the present prospective cohort study, percutaneous coronary procedures were performed via DRA or TRA in 2 study groups. All consecutive participants underwent DRA from September 2021 to March 2022 and TRA from April 2022 to June 2022. Ultrasonography was performed preprocedurally in the DRA group, and patients with small distal artery diameters (<2 mm) were excluded. The same 6-Fr sheaths and standard air-filled compression devices were used in both groups. The primary endpoint was RAO in ultrasound sonography on the first postprocedural day, and the secondary endpoints were the success rate, access time, angiography time, radial artery spasms, and vascular access complications. ResultsA total of 298 patients were assigned to the DRA group and 278 to the TRA group. The RAO rate was significantly higher in the TRA group than in the DRA group (10.1 % vs 0.9 %; P = 0.0001; OR, 0.08, 95 % CI, 0.01–0.27). The success rate was significantly higher in the TRA group (96 % vs 90.2 %; P = 0.009). Access crossovers were done on 12 patients (4.0 %) in the TRA group and 24 patients (9.8 %) in the DRA group (P < 0.001). The mean access time was significantly lower in the TRA group than in the DRA group (1.9 min vs 2.9 min; P < 0.001). The mean angiography time did not significantly differ between the groups (10.2 min in the TRA group vs 9.9 min in the DRA group). The rate of radial artery spasms was not significantly different between the 2 groups (13.8 % in the TRA group vs 14.5 % in the DRA group). The rates of access site hematoma (12.4 % vs 2.3 %; P < 0.001) and bleeding (10.7 % vs 4.1; P = 0.005) were significantly higher in the TRA group. ConclusionsDRA was safe and feasible with lower rates of RAO and access site complications than TRA. Thus, it could be used as an alternative approach in percutaneous coronary procedures. However, the trade-off for these advantages of DRA is an increase in cross-over rate, and a decrease in puncture success rate.

Direct angiographic comparison of different velocity-selective saturation, inversion, and DANTE labeling modules on cerebral arteries.

This study evaluated the velocity-selective (VS) MRA with different VS labeling modules, including double refocused hyperbolic tangent, eight-segment B1-insensitive rotation, delay alternating with nutation for tailored excitation, Fourier transform-based VS saturation, and Fourier transform-based inversion. These five VS labeling modules were evaluated first through Bloch simulations, and then using VSMRA directly on various cerebral arteries of healthy subjects. The relative signal ratios from arterial ROIs and surrounding tissues as well as relative arteria-tissue contrast ratios of different methods were compared. Double refocused hyperbolic tangent and eight-segment B1-insensitive rotation showed very similar labeling effects. Delay alternating with nutation for tailored excitation yielded high arterial signal but with residual tissue signal due to the spatial banding effect. Fourier transform-based VS saturation with half the time of other techniques serves as an efficient nonsubtractive VSMRA method, but the remaining tissue signal still obscured some small distal arteries that were delineated by other subtraction-based VSMRA, allowing more complete cancelation of static tissue. Fourier transform-based inversion produced the highest arterial signal in VSMRA with minimal tissue background. This is the first study that angiographically compared five different VS labeling modules. Their labeling characteristics on arteries and tissue and implications for VSMRA and VS arterial spin labeling are discussed.

Abstract 12522: Non-Ischemic Papillary Muscle Rupture Due to MRSA Myocarditis

Case Presentation: A 46-year-old male with diabetes, ESRD, and recurrent MRSA bacteremia, presented with septic shock and suffered cardiac arrest. Following resuscitation EKG showed inferolateral ischemia. TTE revealed acute mitral valve regurgitation resulting from posteromedial papillary muscle rupture (PMR). An intra-aortic balloon pump was implanted for cardiogenic shock. Coronary angiography revealed right dominant circulation and thrombotic occlusion of a small caliber distal left circumflex artery (LCX). Emergent mitral valve replacement surgery was performed. Pathologic analysis of the excised muscle and leaflet showed marked acute inflammation, bacterial invasion, and myocyte necrosis, confirming non-ischemic rupture due to MRSA myocarditis. Discussion: PMR predominantly occurs after MI, complicating 0.03% of STEMI cases in the reperfusion era. Non-ischemic causes are rare. Coexistence of myocarditis, infective endocarditis (IE), and MI poses a challenge in determining etiology. Establishing causation guides whether to expedite emergent valve surgery or focus on cardiomyocyte salvage by revascularization. The posteromedial papillary muscle is most commonly involved in PMR due to single blood supply from the PDA (most commonly a branch of the RCA, and less commonly the LCX). Coronary angiography, postoperative histopathology, and culture results determined the etiology of PMR was fulminant MRSA bacteremia culminating in myocarditis. Bacterial colonization and resultant inflammation induced physical and mechanical strain leading to complete rupture. The occluded LCX was incidental, and may have been the result of septic embolization, which occurs in up to 65% of left-sided IE. Albeit rare, non-ischemic etiologies must be considered when the anatomic presentation of acute PMR on TTE is incongruent with angiography. Definitive treatment relies on surgical intervention and mechanical circulatory support is often necessary.

Endovascular treatment of distal medium vessel occlusions using microcatheter aspiration thrombectomy.

Recent studies suggest that endovascular treatment (EVT) in distal medium vessel occlusion (DMVO) stroke is beneficial even beyond middle cerebral artery (MCA) - M2 segment. However, data about aspiration thrombectomy of DMVOs is scarce since common state-of-the-art aspiration catheters are usually too large for small distal intracranial arteries. We report our initial experiences using the microcatheter aspiration thrombectomy (MAT) technique as frontline therapy for acute DMVOs in the MCA territory. We retrospectively analyzed all acute ischemic stroke (AIS) patients that underwent MAT of a primary or secondary DMVO in the M3 or M4 segment between January 2019 and October 2021. Recanalization rates, procedural safety and outcome data were recorded. MAT of acute M3 and M4 occlusions was performed in 19 patients with AIS. Six had isolated DMVO strokes, 13 had secondary DMVOs during EVT of a proximal large vessel occlusion. Successful revascularization to DMVO TICI ≥ 2b was achieved in 58% (11/19) with a single pass in all of them. The median National Institutes of Health Strokes Scale (NIHSS) score at admission and discharge was 12 and 3, respectively. 68% (13/19) of the patients had a good clinical outcome at discharge (modified Rankin Scale 0-2). No symptomatic complications related to MAT occurred. MAT of DMVOs in the MCA territory is technically feasible and effective. Compared to stent retriever-based thrombectomy in DMVOs the hemorrhagic complication rate appears notably lower. Further studies are needed to validate the benefit of mechanical thrombectomy in the distal intracranial vasculature.

Time-of-Flight Intracranial MRA at 3 T versus 5 T versus 7 T: Visualization of Distal Small Cerebral Arteries.

Background Three-dimensional (3D) time-of-flight (TOF) MR angiography (MRA) at 7 T has been reported to have high image quality for visualizing small perforating vessels. However, B1 inhomogeneity and more physiologic considerations limit its applications. Angiography at 5 T may provide another choice for intracranial vascular imaging. Purpose To evaluate the image quality and cerebrovascular visualization of 5-T 3D TOF MRA for visualizing intracranial small branch arteries. Materials and Methods Participants (healthy volunteers or participants with a history of ischemic stroke undergoing intracranial CT angiography or MRA for identifying steno-occlusive disease) were prospectively included from September 2021 to November 2021. Each participant underwent 3-T, 5-T, and 7-T 3D TOF MRA with use of customized MR protocols within 48 hours. Radiologist scoring from 0 (invisible) to 3 (excellent) and quantitative assessment were obtained to evaluate the image quality. The Friedman test was used for comparison of characteristics derived from 3 T, 5 T, and 7 T. Results A total of 12 participants (mean age ± SD, 38 years ± 9; nine men) were included. Visualizations of the distal arteries and small vessels at 5-T TOF MRA were significantly higher than those at 3 T (median score: 3.0 vs 2.0, all P < .001 for distal segments and lenticulostriate artery; median score: 2.0 vs 0, P < .001 for pontine artery). The total length of small vessel branches detected at 5 T was larger than that at 3 T (5.1 m ± 0.7 vs 1.9 m ± 0.4; P < .001). However, there was no evidence of a significant difference compared with 7 T in either the depiction of distal segments and small vessel branches (average median score, 2.5; all P > .05) or the quantitative measurements (total length, 5.6 m ± 0.5; P = .41). Conclusion Three-dimensional time-of-flight MR angiography at 5 T presented the capability to provide superior visualization of distal large arteries and small vessel branches (in terms of subjective and quantitative assessment) to 3 T and had image quality similar to 7 T. © RSNA, 2022 Online supplemental material is available for this article. An earlier incorrect version appeared online. This article was corrected on September 14, 2022.

Periprocedural and 30-day outcomes of robotic-assisted percutaneous coronary intervention used in the intravascular imaging guidance

In recent years, there have been several reports on robotic-assisted percutaneous coronary intervention (R-PCI), but few studies have been conducted on R-PCI performed under intravascular imaging guidance. To elucidate the periprocedural and postoperative 30-day outcomes of intravascular imaging-guided R-PCI, we performed a retrospective observational study on all patients in 102 consecutive cases who underwent R-PCI under intravascular imaging guidance at a single center in Japan from June 12, 2019 to February 18, 2021. The primary end point was 30-day survival, and the secondary end point was the incidence of complications. Intravascular imaging-guided R-PCI was performed 110 times in total on 125 lesions. The medians of procedural time, fluoroscopy time, contrast volume, patient entrance skin dose, and radiation exposure to the main operator were 49 min, 16 min, 67 mL, 0.62 Gy, and 0 μSv, respectively. Furthermore, 60.0% of target lesion branches were American College of Cardiology Foundation/American Heart Association classification type B2 or type C. However, in all cases, lesion dilatation was successful, and the final Thrombolysis in Myocardial Infarction flow grade was 3. The combination of manual operation was required in 12.7% of all cases, but 30-day survival was confirmed in all cases. There were two problems at the puncture site. One small distal branch artery dissection occurred due to manual operation, but no cardiovascular events (myocardial infarction, stroke) occurred and no target lesion restenosis was observed within 30 days of R-PCI. Hence, R-PCI using intravascular imaging demonstrated highly satisfactory treatment outcomes, and no complication caused by robotic operation was observed.

Human Hypertension Blood Flow Model Using Fractional Calculus.

The blood flow dynamics in human arteries with hypertension disease is modeled using fractional calculus. The mathematical model is constructed using five-element lumped parameter arterial Windkessel representation. Fractional-order capacitors are used to represent the elastic properties of both proximal large arteries and distal small arteries measured from the heart aortic root. The proposed fractional model offers high flexibility in characterizing the arterial complex tree network. The results illustrate the validity of the new model and the physiological interpretability of the fractional differentiation order through a set of validation using human hypertensive patients. In addition, the results show that the fractional-order modeling approach yield a great potential to improve the understanding of the structural and functional changes in the large and small arteries due to hypertension disease.

Mechanical revascularization using Solitaire AB device for acute limb ischemia secondary to popliteal and infrapopliteal embolic occlusion.

ObjectiveAcute limb ischemia is one of the most common arterial emergencies. The data of mechanical revascularization using Solitaire AB device coupled with thromboaspiration for the treatment of popliteal and infrapopliteal acute limb ischemia are limited. The aim of this study was to review the preliminary safety and effectiveness.MethodsWe performed a single-center retrospective review of patients with popliteal and infrapopliteal acute limb ischemia treated with Solitaire AB device coupled with thromboaspiration from February 2019 to May 2020. Adjunctive balloon angioplasty was performed to correct coexisting atherosclerotic stenosis. Technical success was defined as successful deployment of the Solitaire AB device across the occlusive segment and successful retrieval without the use of adjunctive catheter-directed thrombolysis or balloon angioplasty. Clinical success was defined as the relief of symptoms related to acute limb ischemia. Follow-up outcomes were also reviewed.ResultsThere were 15 consecutive patients who underwent 16 Solitaire AB devices. Technical success was achieved in 11 (73.3%) patients. Of the unsuccessful patients, double-stent retrievers were employed in 1 (6.7%) patient. Two patients who encountered residual clots in distal small arteries underwent adjunctive catheter-directed thrombolysis. An adjunctive balloon angioplasty was required in 1 (6.7%) patient. All patients had notable acute limb ischemia symptom relief after the procedures. Clinical success was achieved in 14 (93.3%) patients. Besides one patient encountered minor amputation, the major amputation was prevented in all patients. No device-related complications or distal embolization events were recorded during the procedures. At the follow-up of 12 months, all surviving patients remained symptom-free, the patency was achieved in 12 (80%) patients and the limb salvage was 100%.ConclusionsPreliminary outcomes suggest that mechanical revascularization using Solitaire AB device coupled with manual thromboaspiration appears to be a rapid, safe, and effective modality that appears to reduce the requirement for catheter-directed thrombolysis.Advances in knowledgeThese findings may add a promising recanalization therapy for acute embolic occlusion of the acute limb ischemia secondary to popliteal and infrapopliteal arteries.

Near-Occlusion is a Common Variant of Carotid Stenosis: Study and Systematic Review.

Symptomatic carotid near-occlusion is often described as rare. Recent studies have shown that near-occlusions are overlooked, especially near-occlusion without full collapse (with a small but normal-appearing distal internal carotid artery). To assess the prevalence of near-occlusion among symptomatic ≥50% carotid stenosis, incidence of symptomatic near-occlusion, and review the literature. Prospective controlled single-center cross-sectional study. Consecutive cases with symptomatic ≥50% carotid stenosis were examined with computed tomography angiography (CTA). The CTAs were assessed for near-occlusion by two observers. A systematic literature review was performed with emphasis on how study design affects prevalence estimate. Totally, 186 patients with symptomatic ≥50% carotid stenosis were included, 34% (n = 63, 95% CI 27, 41) had near-occlusion. The incidence of symptomatic near-occlusion was 3.4 (95% CI 2.5, 4.2) per 100,000 person-years. Inter-rater κ was 0.71. The average prevalence of near-occlusion among symptomatic ≥50% carotid stenosis was higher in studies with good design (30%, range 27%-34%) than studies without good design (9%, range 2%-10%). Near-occlusion is common variant of symptomatic ≥50% carotid stenosis, both in the current study and in all previous studies of good design. Studies that suggest that near-occlusion is rare have had methodological issues.

A case report: Early findings of distal vessel occlusion pre and post-thrombolysis using three-dimensional black blood vessel wall imaging in acute stroke.

Distal vessel occlusion of an eloquent area in acute stroke may lead to significant disability. Advances in magnetic resonance imaging enable direct visualization of thrombus within the small distal intracranial artery. The evolution of medical devices for mechanical thrombectomy has allowed the smaller distal vessels to be treated. It may change the approach to how we treat distal vessel occlusion in the future. This case highlights the value of three-dimensional black blood vessel wall imaging assessing distal vessel occlusion and respond towards reperfusion therapy.

Chronic Hypoxia Decreases Endothelial Connexin 40, Attenuates Endothelium-Dependent Hyperpolarization-Mediated Relaxation in Small Distal Pulmonary Arteries, and Leads to Pulmonary Hypertension.

BackgroundAbnormal endothelial function in the lungs is implicated in the development of pulmonary hypertension; however, there is little information about the difference of endothelial function between small distal pulmonary artery (PA) and large proximal PA and their contribution to the development of pulmonary hypertension. Herein, we investigate endothelium‐dependent relaxation in different orders of PAs and examine the molecular mechanisms by which chronic hypoxia attenuates endothelium‐dependent pulmonary vasodilation, leading to pulmonary hypertension.Methods and ResultsEndothelium‐dependent relaxation in large proximal PAs (second order) was primarily caused by releasing NO from the endothelium, whereas endothelium‐dependent hyperpolarization (EDH)–mediated vasodilation was prominent in small distal PAs (fourth–fifth order). Chronic hypoxia abolished EDH‐mediated relaxation in small distal PAs without affecting smooth muscle–dependent relaxation. RNA‐sequencing data revealed that, among genes related to EDH, the levels of Cx37, Cx40, Cx43, and IK were altered in mouse pulmonary endothelial cells isolated from chronically hypoxic mice in comparison to mouse pulmonary endothelial cells from normoxic control mice. The protein levels were significantly lower for connexin 40 (Cx40) and higher for connexin 37 in mouse pulmonary endothelial cells from hypoxic mice than normoxic mice. Cx40 knockout mice exhibited significant attenuation of EDH‐mediated relaxation and marked increase in right ventricular systolic pressure. Interestingly, chronic hypoxia led to a further increase in right ventricular systolic pressure in Cx40 knockout mice without altering EDH‐mediated relaxation. Furthermore, overexpression of Cx40 significantly decreased right ventricular systolic pressure in chronically hypoxic mice.ConclusionsThese data suggest that chronic hypoxia‐induced downregulation of endothelial Cx40 results in impaired EDH‐mediated relaxation in small distal PAs and contributes to the development of pulmonary hypertension.

A novel sequence for simultaneous measurement of whole-brain static and dynamic MRA, intracranial vessel wall image, and T1 -weighted structural brain MRI.

To propose a highly time-efficient imaging technique named improved simultaneous noncontrast angiography and intraplaque hemorrhage (iSNAP) for simultaneous assessment of lumen, vessel wall, and blood flow in intracranial arteries. iSNAP consists of pulsed arterial spin labeling preparations and 3D golden angle radial acquisition. Images were reconstructed by k-space weighted image contrast (KWIC) method with optimized data-sharing strategies. Dynamic MRA for blood flow assessment was obtained from iSNAP by reconstruction at multiple inversion times and image subtraction, static MRA by both image subtraction approach and phase-sensitive inversion recovery technique, and vessel wall images by both reconstruction at zero-crossing time-point of blood and phase-sensitive inversion recovery. A T1 -weighted brain MRI was also reconstructed from iSNAP. Preliminary comparison of iSNAP against the dedicated dynamic MRA sequence 4D-TRANCE, MRA/vessel wall imaging sequence SNAP, and vessel wall imaging sequence T1 -weighted VISTA was performed in healthy volunteers and patients. iSNAP has whole-brain coverage and takes ~6.5 min. The dedicated reconstruction strategies are feasible for each iSNAP image contrast and beneficial for image SNR. iSNAP-dynamic MRA yields similar dynamic flow information as 4D-TRANCE and allows more flexible temporal resolution. The 2 types of iSNAP static MRA images complement each other in characterizing both proximal large arteries and distal small arteries. Depiction of vessel wall lesions in iSNAP vessel wall images is better than SNAP and may be similar to T1 -weighted VISTA, although the images are slightly blurred. iSNAP provides a time-efficient evaluation of intracranial arteries and may have great potential for comprehensive assessment of intracranial vascular conditions using a single sequence.

A novel algorithm for refining cerebral vascular measurements in infants and adults

BackgroundComprehensive quantification of intracranial vascular characteristics by vascular tracing provides an objective clinical assessment of vascular structure. However, weak signal or low contrast in small distal arteries, artifacts due to volitional motion, and vascular pulsation are challenges for accurate vessel tracing from 3D time-of-flight (3D-TOF) magnetic resonance angiography (MRA) images. New MethodA vascular measurement refinement algorithm is developed and validated for robust quantification of intracranial vasculature from 3D-TOF MRA. After automated vascular tracing, centerline positions, lumen radii and centerline deviations are jointly optimized to restrict traces to within vascular regions in the straightened curved planar reformation (CPR) views. The algorithm is validated on simulated vascular images and on repeat 3D-TOF MRA acquired from infants and adults. ResultsThe refinement algorithm can reliably estimate vascular radius and correct deviated centerlines. For the simulated vascular image with noise level of 1 and deviation of centerline of 3, the mean radius difference is below 15.3 % for scan-rescan reliability. Vascular features from repeated clinical scans show significantly improved measurement agreement, with intra-class correlation coefficient (ICC) improvement from 0.55 to 0.7 for infants and from 0.59 to 0.92 for adults. Comparison with Existing MethodsThe refinement algorithm is novel because it utilizes straightened CPR views that incorporate information from the entire artery. In addition, the optimization corrects centerline positions, lumen radii and centerline deviations simultaneously. ConclusionsIntracranial vasculature quantification using a novel refinement algorithm for vascular tracing improves the reliability of vascular feature measurements in both infants and adults.

Susceptibility to high-altitude pulmonary edema is associated with increased pulmonary arterial stiffness during exercise.

High-altitude pulmonary edema (HAPE), a reversible form of capillary leak, is a common consequence of rapid ascension to high altitude and a major cause of death related to high-altitude exposure. Individuals with a prior history of HAPE are more susceptible to future episodes, but the underlying risk factors remain uncertain. Previous studies have shown that HAPE-susceptible subjects have an exaggerated pulmonary vasoreactivity to acute hypoxia, but incomplete data are available regarding their vascular response to exercise. To examine this, seven HAPE-susceptible subjects and nine control subjects (HAPE-resistant) were studied at rest and during incremental exercise at sea level and at 3,810 m altitude. Studies were conducted in both normoxic (inspired Po2 = 148 Torr) and hypoxic (inspired Po2 = 91 Torr) conditions at each location. Here, we report an expanded analysis of previously published data, including a distensible vessel model that showed that HAPE-susceptible subjects had significantly reduced small distal artery distensibility at sea level compared with HAPE-resistant control subjects [0.011 ± 0.001 vs. 0.021 ± 0.002 mmHg-1; P < 0.001). Moreover, HAPE-susceptible subjects demonstrated constant distensibility over all conditions, suggesting that distal arteries are maximally distended at rest. Consistent with having increased distal artery stiffness, HAPE-susceptible subjects had greater increases in pulmonary artery pulse pressure with exercise, which suggests increased proximal artery stiffness. In summary, HAPE-susceptible subjects have exercise-induced increases in proximal artery stiffness and baseline increases in distal artery stiffness, suggesting increased pulsatile load on the right ventricle.NEW & NOTEWORTHY In comparison to subjects who appear resistant to high-altitude pulmonary edema, those previously symptomatic show greater increases in large and small artery stiffness in response to exercise. These differences in arterial stiffness may be a risk factor for the development of high-altitude pulmonary edema or evidence that consequences of high-altitude pulmonary edema are long-lasting after return to sea level.

Successful surgical retrieval of Celt ACD\xae vascular closure device embolised in the tibioperoneal trunk

BackgroundThis report presents a case of surgical retrieval of a Celt ACD® vascular closure device (VCD) situated in the tibioperoneal trunk, following a failed attempt at deployment. Existing literature mostly recommends an endovascular approach when attempting to retrieve embolised VCDs.Case presentationA 55 year old male presented with right sudden right lower limb pain and numbness 1 week following a successful left retrograde superficial femoral artery (SFA) angioplasty. Computed tomography (CT) angiogram revealed that the Celt ACD® VCD had embolised in the right tibioperoneal trunk. An endovascular approach was initially attempted to retrieve the VCD; however, this was unsuccessful due to the small diameter of the target artery. Due to the failure of the endovascular approach, surgical exploration of the right tibioperoneal trunk was undertaken, which led to the successful retrieval of the embolised VCD.ConclusionThe case presented herein demonstrates the critical need for swift and decisive surgical exploration of patients with suspected embolisation of Celt ACD® devices in smaller distal arteries. Our experience has led to the recommendation that, due to the sharp edges of the Celt ACD® accompanied with the small diameter of the occluded vessels, surgical exposure and retrieval is the safest option if endovascular retrieval is unsuccessful.

Carotid near-occlusion can be identified with ultrasound by low flow velocity distal to the stenosis.

Most carotid near-occlusions are indistinguishable from conventional ≥ 50% stenosis on ultrasound, demonstrating high peak systolic velocity (PSV) in the stenosis. To study whether the velocity distal to the stenosis can separate high PSV near-occlusion from conventional ≥ 50% stenosis. We included patients with ≥ 50% carotid stenosis with high PSV (≥125 cm/s), examined with both computed tomography angiography (CTA) and ultrasound within 30 days, and a distal velocity measurement was performed. Based on CTA, cases were divided into three groups: conventional stenosis; near-occlusion without full collapse (NwoC; normal-appearing albeit small distal artery); and near-occlusion with full collapse (NwC; threadlike distal artery). Distal Doppler ultrasound flow velocities were compared between these groups. Sixty patients were included: 33 patients with conventional stenosis; 20 patients with NwoC; and seven patients with NwC. Mean distal PSV was 93, 63, and 21 cm/s ( P < 0.001) and mean distal end-diastolic velocity was 30, 24, and 5 cm/s ( P < 0.001), respectively. A distal PSV < 50 cm/s was 63% sensitive and 94% specific for separating both types of near-occlusion from conventional stenosis. In high PSV carotid stenoses, the distal velocity was lower in near-occlusions than conventional carotid stenosis. Distal velocities warrant further investigation in diagnostic studies.

A two scale modeling and computational framework for vibration-induced Raynaud syndrome

Hand-Arm Vibration syndrome (HAVS), usually caused by long-term use of hand-held power tools, can in certain manifestations alter the peripheral blood circulation in the hand-arm region. HAVS typically occurs after exposure to cold, causing an abnormally strong vasoconstriction of blood vessels. A pathoanatomical mechanism suggests that a reduction of the lumen of the blood vessels in VWF (Vibration White Finger) subjects, due to either hypertrophy or thickening of the vessel wall, may be at the origin of the disease. However, the direct and indirect effects of the load of the hand-held tools on the structure of blood vessels remain controversial:.one hypothesis is the mechanical action of vibration on the local acral dysregulation and/or on the vessel histomorphological modifications. Another hypothesis is the participation of the sympathetic nervous system to this dysregulation. In this paper, we assume the modifications as mechanobiological growth and the load-effect relationship may be interpreted as directly or indirectly induced. This work is the first attempt to model the effect of vibration through soft tissues onto the distal capillaries, addressing the double paradigm of multi space-time scales, i.e. low period vibration versus high time constant of the growth phenomenon as well as vibrations propagating in the macroscopic tissue including the microscopic capillary structures subjected to a pathological microstructural evolution. The objective is to lay down the theoretical basis of growth modeling for the small distal artery, with the ability to predict the geometrical and structural changes of the arterial walls caused by vibration exposure. We adopt the key idea of splitting the problem into one global vibration problem at the macroscopic scale and one local growth problem at the micro level. The macroscopic hyperelastic viscous dynamic model of the fingertip cross-section is validated by fitting experimental data. It is then used in steady-state vibration conditions to predict the mechanical fields in the close vicinity of capillaries. The space scale transfer from macroscopic to microscopic levels is ensured by considering a representative volume element (RVE) embedding a single capillary in its center. The vibrations emitted by the hand held power tool are next linked to the capillary growth through the adopted biomechanical growth model at the capillary level. The obtained results show that vibrations induce an increase of the thickness of the capillary's wall, thereby confirming the scenario of vibrations induced reduction of the lumen of blood vessels.

Therapeutic effect of prostaglandin E1 in monocrotaline-induced pulmonary arterial hypertension rats

Pulmonary arterial hypertension (PAH) is a severe pulmonary vascular disease characterized by sustained increase in pulmonary arterial pressure and excessive thickening and remodeling of distal small pulmonary arteries. During disease progression, PAH include increase in mean pulmonary arterial pressure, right ventricular (RV) enlargement, increased pulmonary vascular resistance, and smooth muscle hypertrophy in pulmonary arterioles. Several anti-PAH therapies targeting various pathways involved in PAH progression have been approved by the Food and Drug Adminstration. However, many of the currently available anti-PAH drugs suffer from a number of limitations, including short biological half-life, and poor pulmonary selectivity. Prostaglandin E1 (PGE1) is a potent vasodilator with selectivity toward pulmonary circulation when it is administered via the pulmonary route. However, PGE1 has a very short half-life of 5–10 minutes. Therefore, we hypothesized that long-term effect of PGE1 could reduce mal-adaptive structural remodeling of the lung and heart and prevent ventricular arrhythmias in monocrotaline-induced rat model of PAH. Our results revealed that PGE1 reduced ventricular hypertrophy, protein expressions of endothelin-1 and endothelin receptor A, and the expression of fibrosis. These results support the notion that PGE1 can improve the functional properties of RV, highlighting its potential benefits for heart and lung impairment.

Life-Threatening Pancreaticoduodenal Artery Aneurysm with Median Arcuate Ligament Syndrome

A 60-year-old female presented with acute onset epigastric abdominal pain and transient hypotension. Her pain progressively worsened over a 12-hour period and resolved within 24 hours. Abdominal CT showed a mesenteric hematoma of unknown source. Interventional Radiology proceeded with mesenteric arteriography, demonstrating celiac axis stenosis and embolized a superior pancreaticoduodenal artery (PDA) pseudoaneurysm. The findings were consistent with post-stenotic dilatation and subsequent aneurysmal formation due to Median Arcuate Ligament Syndrome. The patient remained stable and was discharged home. The median arcuate ligament is a fibrous arch that straddles the aorta, connecting the diaphragmatic crura on each side of the aortic hiatus. The ligament typically lies superior to the origin of the celiac trunk; however, in 10-24% of the population, the ligament inserts lower, crossing the proximal portion of the celiac trunk, causing symptomatic compression in about 1%. Median Arcuate Ligament Syndrome is characterized by stenosis of the celiac artery secondary to impingement by the median arcuate ligament. It is a rare diagnosis of exclusion, classically presenting with postprandial abdominal pain, abdominal bruit, and weight loss. Stenosis of the celiac trunk causes decreased perfusion of the foregut. With increased retrograde blood flow, blood pressures, and wall tension, the smaller distal arteries' blood vessel wall can become damaged and even lead to aneurysm formation. Splanchnic artery aneurysms are relatively rare conditions with aneurysm rupture of greatest concern due to a mortality rate of 30% with PDA rupture.Figure 1The diagnosis of both MALS and PDA aneurysms can be made by angiography or incidentally on CT/MRI. Dynamic MRA can observe the celiac axis throughout the respiratory cycle, demonstrating the pathognomonic augmentation of stenosis of the artery during the expiratory phase to clinch the diagnosis of MALS and further rule out other causes of stenosis like atherosclerosis. Treatment for MALS with PDA aneurysm involves: Celiac axis/distal vessel revascularization and Median Arcuate Ligament release, which is paramount for prevention of recurrence. In conclusion, Median Arcuate Ligament Syndrome (MALS) is a rare cause of postprandial abdominal pain and is a diagnosis of exclusion. A potential life-threatening complication of MALS involves aneurysm formation, which if not identified can lead to rupture and sudden death without intervention.