Ultrasound imaging of the arterial system

Traumatic injury to vascular prosthetic anastomosis: A case report and diagnostic approach

INTRODUCTION

Traumatic injury of a vascular prosthesis-to-prosthesis anastomosis leading to an extravasation and pseudoaneurysm is rare. If not identified the complications associated with this condition can lead to high morbidity and mortality and require surgical treatment.

CASE

We describe a patient who presented with a tear in prosthesis-prosthesis anastomosis eight years after implantation resulting in a pseudoaneurysm. The patient had a severe fall prior to the non-symptomatic leakage. The complication was successfully treated by re-lining the graft with a new anastomosis at the Department of Vascular and Endovascular Surgery, Kolding Hospital in Denmark.

DISCUSSION

Cause of tear is speculated to be due to weakness at site of reconstruction, fabric degradation, and/or degradation of suture material.

CONCLUSION

Late prosthesis-prosthesis anastomosis tear caused by a traumatic event is rare. In the event of a late tear, anamnesis and histological analysis of involved material is important.

Temporal Pattern Analysis of Ultrasound Surveillance Data in Vascular Connective Tissue Disorders

BACKGROUND

Ehlers-Danlos syndrome (EDS), Marfan syndrome (MFS), and Loeys-Dietz syndrome (LDS) are connective tissue disorders frequently associated with vascular aneurysm formation, dissections, and subsequent major complications. Regular imaging surveillance is recommended for these conditions. However, no guidelines currently exist regarding imaging modality or surveillance intervals.

METHODS

This retrospective single-center observational study analyzed clinical and imaging data of patients attending an outpatient clinic for vascular connective tissue disorders between August 2008 and January 2024. Imaging (1424 data points in total) and clinical data were extracted from electronic health records. Analysis primarily included a comparison of vessel diameter progression across imaging modalities, with an additional review of the clinical history of vascular events.

RESULTS

In total, 19 patients with vascular connective tissue disorders (vCTDs) underwent consultations at our outpatient clinic. Nine (47.4%) patients experienced vascular events, while two (10.5%) passed away during the study period. Multimodal imaging surveillance revealed a tendency towards arterial diameter increase. Consistent ultrasound monitoring provided more reliable diameter progression data for the same arterial segment than a combination of imaging modalities. Temporal analysis indicated a tendency for the continuous growth of the abdominal aorta, the common and internal carotid artery, and the common femoral and popliteal artery.

CONCLUSION

The study highlights the importance of standardized, modality-specific imaging protocols in monitoring patients with vCTDs. The variability in disease progression among these patients further complicates surveillance strategies, contemplating the need for individualized approaches. Further research and prospective multicenter studies are required to refine and improve monitoring protocols.

Comparison of the Haemodynamic Performance of Various Treatment Options for Aorto-Iliac Occlusive Disease

Introduction

Several surgical and endovascular techniques are used during the treatment of aorto-iliac occlusive disease. Aortobifemoral bypass (AoBFB) is the standard of care, but other options such as axillobifemoral (AxBFB) bypass, aorto-iliac kissing stents (KS), and covered endovascular reconstruction of aortic bifurcation (CERAB) are also available. This study aimed to perform a computational comparison of these four modalities to investigate their haemodynamic performance.

Report

Eight patient specific anatomies were analysed, with each of the abovementioned techniques used to treat two anatomies. The CT angiograms were segmented from the renal (or axillary) to common femoral arteries and the 3D geometries were exported. A commercial finite volume solver was implemented for numerical simulations. Outcomes that were assessed were pressure drop (ΔP) between the inlet and the outlet for every configuration and haemodynamic indices of Time Average Wall Shear Stress (TAWSS), Oscillatory Shear Index (OSI), and Relative Residence Time (RRT) as markers of a thrombogenic environment. The results indicate that maximum ΔP was observed at peak systole for all models, with values ranging between 12 mmHg and 21 mmHg for the AoBFB, 64 mmHg and 96 mmHg for the AxBFB, 31 mmHg and 46 mmHg for the KS, and 43 mmHg and 46 mmHg for the CERAB configuration. TAWSS, OSI, and RRT varied among different configurations, mostly presenting values well above thrombogenic thresholds. Regarding RRT, the percentage of total surface area presenting such values is 2.5%, 3.2%, 2%, and 4.3% for the AoBFB, AxBFB, KS, and CERAB configurations, respectively.

Discussion

Computational modelling indicates a favourable haemodynamic performance of AoBFB compared with the other configurations. This leads to a smaller pressure drop and sconsequently a higher pressure in the outlet of the conduit, which is the perfusion pressure of the limb. Notably, lower patency rates of the latter modalities cannot be explained based on haemodynamic indices.

Phasicity and resistance of the arterial spectral Doppler waveform in a canine femoral focal artery stenosis model

INTRODUCTION

This study aims to evaluate changes in the arterial spectral Doppler waveform in a canine artery stenosis model.

METHODS

Canine femoral artery stenosis models were established in 12 beagle dogs. Doppler waveforms were recorded in the femoral artery preoperatively and postoperatively in the femoral artery and at the ankle after formation of a 50%, 70%, and 90% stenosis or occlusion. Major descriptors for arterial Doppler waveform were used to analyse waveforms.

RESULTS

The proportion of multiphasic waveforms proximal to a moderate stenosis decreased compared to normal baseline, although the difference was not statistically significant, whereas the decreases at the stenosis, distal to the stenosis, and at the ankle were significant (p < 0.05). The decreases in arteries with a more severe stenosis or occlusion were significant at all locations (p < 0.05). The proportion of high resistive waveforms decreased significantly at the ankle in the arteries with a moderate stenosis (50%) (p = 0.002), but the decreases proximal to, at, and distal to the stenosis were not significant. The decreases were significant at all locations in the arteries with a more severe stenosis (p < 0.05). The decrease was significant at the ankle in the arteries with an occlusion (p < 0.001) but not significant pre, at, and post an occlusion.

CONCLUSIONS

Phasicity and resistance of Doppler waveforms alter in canine femoral arteries with a stenosis. Phasicity change seems more sensitive in response to an arterial stenosis than resistance change. Additional information on arterial resistance could be obtained using end-diastolic ratios, resistive indices, and potentially end-systolic notch velocity measurements.

Duplex Analysis of Cannulated Vessels in Peripheral Veno-Arterial Extracorporeal Membrane Oxygenation

Background and objectives: Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) cannulas have major repercussions on vascular hemodynamics that can potentially lead to limb ischemia. Duplex ultrasound enables the non-invasive analysis of vascular hemodynamics. This study aims to describe the duplex parameters of the femoral vessels during V-A ECMO support, investigate differences between cannulated and non-cannulated vessels, and analyze the variations in the case of limb ischemia and intra-aortic balloon pumps (IABPs). Methods: Nineteen adults (≥18 years), supported with femoro-femoral V-A ECMO, underwent a duplex analysis of the superficial femoral arteries (SFAs) and veins (FVs). Measured parameters included flow velocities, waveforms, and vessel diameters. Results: 89% of patients had a distal perfusion cannula during duplex analysis and 21% of patients developed limb ischemia. The mean peak systolic flow velocity (PSV) and end-diastolic flow velocity (EDV) of the SFAs on the cannulated side were, respectively, 42.4 and 21.4 cm/s. The SFAs on the non-cannulated side showed a mean PSV and EDV of 87.4 and 19.6 cm/s. All SFAs on the cannulated side had monophasic waveforms, whereas 63% of the SFAs on the non-cannulated side had a multiphasic waveform. Continuous/decreased waveforms were seen in 79% of the FVs on the cannulated side and 61% of the waveforms of the contralateral veins were respirophasic. The mean diameter of the FVs on the cannulated side, in patients who developed limb ischemia, was larger compared to the FVs on the non-cannulated side with a ratio of 1.41 ± 0.12. The group without limb ischemia had a smaller ratio of 1.03 ± 0.25. Conclusions: Femoral cannulas influence flow velocities in the cannulated vessels during V-A ECMO and major waveforms alternations can be seen in all SFAs on the cannulated side and most FVs on the cannulated side. Our data suggest possible venous stasis in the FV on the cannulated side, especially in patients suffering from limb ischemia.

The “Black Pattern”, a Simplified Ultrasound Approach to Non-Traumatic Abdominal Emergencies

Background: A key issue in abdominal US is the assessment of fluid, which is usually anechoic, thus appearing “black”. Our approach focuses on searching for fluid in non-traumatic patients, providing a new, simplified method for point-of-care US (POCUS). Objective: Fluid assessment is based on a three-step analysis that we can thus summarize. 1. Look for black where it should not be. This means searching for effusions or collections. 2. Check if black is too much. This means evaluating anatomical landmarks where fluid should normally be present but may be abnormally abundant. 3. Look for black that is not clearly black. This means evaluating fluid aspects, whether wholly anechoic or not (suggesting heterogeneous or corpusculated fluid). Discussion: Using this simple method focused on US fluid presence and appearance should help clinicians to make a timely diagnosis. Although our simplified, systematic algorithm of POCUS may identify abnormalities; this usually entails a second-level imaging. An accurate knowledge of the physio–pathological and anatomical ultrasound bases remains essential in applying this algorithm. Conclusion: The black pattern approach in non -traumatic emergencies may be applied to a broad spectrum of abnormalities. It may represent a valuable aid for emergency physicians, especially if inexperienced, involved in a variety of non-traumatic scenarios. It may also be a simple and effective teaching aid for US beginners.

Quantitative Evaluation of Post-stenotic Blood Flow Disturbance in Canine Femoral Artery Stenosis Model: An Early Experience With Vector Flow Imaging

Objective

To investigate the value of Vector Flow Imaging (V Flow) in the assessment of post-stenotic turbulence in the canine arterial stenosis model.

Materials and Methods

Canine femoral artery stenosis models were established using ameroid constrictors in 12 beagle dogs. 50% and then 70% femoral artery stenoses were confirmed by selective femoral artery angiography. V Flow was used to measure femoral artery flow turbulence index (Tur) preoperatively as a baseline. After establishing of a 50% and then 70% stenoses, the Tur indices were recorded in the femoral artery at 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19 mm distal to the stenosis.

Results

Baseline Tur indices of normal canine femoral arteries were <1% in 11 of 12 cases (91.7%). Distal to a 50% stenosis, the Tur index (>1%) was recorded in 83.3–100% cases between 1 and 9 mm, 41.7–58.3% between 11 and 17 mm, and 16.7% at 19 mm. For a 70% stenosis, the Tur index (>1%) occurred in 81.8–100% cases between 1 and 17 mm distal to the stenosis, and 63.6% at 19 mm. The Tur index peaked around 7 mm or 2.3 times of the initial vessel diameter (3 mm) downstream for a 50% stenosis and 11 mm or 3.7 times of vessel diameter downstream for a 70% stenosis.

Conclusion

V Flow with Tur index measurement adds quantitative information of post-stenotic turbulence when assessing an arterial stenosis with ultrasound. Tur index of 1% seems a useful threshold for assessment of flow turbulence in this small sample study. Further studies with larger sample size are needed to evaluate the value of V Flow in clinical applications.

Coronary artery disease and its impact on the pulsatile brain: A functional NIRS study

Recent studies have reported that optical indices of cerebral pulsatility are associated with cerebrovascular health in older adults. Such indices, including cerebral pulse amplitude and the pulse relaxation function (PRF), have been previously applied to quantify global and regional cerebral pulsatility. The aim of the present study was to determine whether these indices are modulated by cardiovascular status and whether they differ between individuals with low or high cardiovascular risk factors (LCVRF and HCVRF) and coronary artery disease (CAD). A total of 60 older adults aged 57-79 were enrolled in the study. Participants were grouped as LCVRF, HCVRF, and CAD. Participants were asked to walk freely on a gym track while a near-infrared spectroscopy (NIRS) device recorded hemodynamics data. Low-intensity, short-duration walking was used to test whether a brief cardiovascular challenge could increase the difference of pulsatility indices with respect to cardiovascular status. Results indicated that CAD individuals have higher global cerebral pulse amplitude compared with the other groups. Walking reduced global cerebral pulse amplitude and PRF in all groups but did not increase the difference across the groups. Instead, walking extended the spatial distribution of cerebral pulse amplitude to the anterior prefrontal cortex when CAD was compared to the CVRF groups. Further research is needed to determine whether cerebral pulse amplitude extracted from data acquired with NIRS, which is a noninvasive, inexpensive method, can provide an index to characterize the cerebrovascular status associated with CAD.

Emergency Point-of-Care Ultrasound Diagnosis of a Femoral Artery Pseudoaneurysm

BACKGROUND

Iatrogenic femoral artery pseudoaneurysm formation after intervention of the femoral artery may present weeks after intervention. We report a case of a patient with delayed pseudoaneurysm diagnosis that was ultimately diagnosed with bedside ultrasound. Importantly, our case demonstrates a patient who had a left-sided atherectomy and angioplasty with microcatheter access of the right femoral artery.

CASE REPORT

A 68-year-old man with multiple comorbidities presented to the Emergency Department (ED) with right inguinal pain, swelling, and overlying skin changes 17 days after an interventional radiology-guided left-sided femoral artery atherectomy and angioplasty. His first postoperative ED visit at an outside hospital led to the diagnosis of a hematoma vs. abscess, with attempted bedside drainage. On presentation to our ED, a bedside ultrasound confirmed arterial pseudoaneurysm formation of the right femoral artery. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: In patients presenting with the constellation of symptoms after arterial site intervention of either side, iatrogenic pseudoaneurysm should be in the differential. Although the patient had atherectomy and angioplasty of the left femoral artery, it is important to highlight that both femoral arteries were accessed during intervention, and thus, both sites are at risk for pseudoaneurysm formation. Emergency sonography can be a useful tool to diagnose, expedite treatment, and avoid potentially harmful invasive procedures in patients presenting with pain and swelling after arterial site intervention.

Doppler ultrasound diagnosis of brachial artery injury due to blunt trauma: A Case Report

The brachial artery is the most common injured vessel in the upper extremity. Although vascular injury following blunt trauma is rare, it is a condition to be considered because it can easily be overlooked unless the clinician has a high suspicion. In this paper, we present a blunt trauma case with brachial arterial injury, upper extremity ischemia, and the need for urgent management to salvage the limb. A 28-year-old male had a right arm swelling, pain, and paleness accompanied by a weak pulse in the right radial artery and right-hand numbness. Following resuscitation, preoperative Doppler ultrasound revealed to the brachial artery injury. The right brachial artery had an occlusion with a thrombus. In spectral Doppler analysis, there were demonstrated parvus et tardus waveform in the distal arteries. Doppler ultrasound provided crucial information to make an accurate and rapid management decision.

Stab wound of the superficial femoral artery early diagnosed by point-of-care Doppler ultrasound

Background

Traumatic vascular injury of the limbs has the potential to cause substantial patient morbidity and mortality, and therefore, early recognition and treatment are crucial to improve outcomes. While patients with hard signs of arterial injury mandate for an immediate surgical intervention, patients presenting with soft signs of arterial injury need further diagnostic evaluation.

Case presentation

A 24-year-old male was admitted to the emergency department after suffering a stab wound in the anterolateral aspect of his left upper thigh. Entry wound measures approximately 3 cm × 0.7 cm; no exit wound was observed. On examination of the injured limb, the thigh was swollen and painful. Skin color was mildly pale and skin temperature was slightly diminished in his leg; leg numbness was also pointed out by the patient. Common femoral artery pulse was normal, while distal pulses were diminished. Point-of-care Doppler ultrasound (DUS) showed a subfascial hematoma in the thigh, which filled on color Doppler, corresponding to a pseudoaneurysm. On spectral Doppler, signs of distal low blood supply were noted. The patient was immediately transferred to the operating room where a 1-cm laceration was found in the anterior aspect of the superficial femoral artery. The involved artery was successfully repaired and distal flow was reestablished, as assessed by clinical examination, pulse palpation and DUS.

Conclusions

Based on its several advantages, DUS should be considered as the first-line diagnostic tool in the diagnostic workup of patients with soft signs of arterial injury.