Anatomical variations of the extracranial internal carotid artery: prevalence, risk factors, and imaging insights from CT-angiography.

PURPOSE: To determine the prevalence of different extracranial internal carotid artery (EICA) variations in CT angiography (CTA) of the neck and its predisposing factors. METHODS: In this retrospective study from 2021 to 2023 conducted in the radiology department of Shafa Hospital, Kerman, Iran, all patients who had undergone neck CTA were included. Expert radiologists blindly examined each CTA image for the following: EICA variations-coiling, kinking, straight morphology, and tortuosity-and the distance between the internal carotid artery and the apex of the epiglottis and the C2 lower margin. RESULTS: Of the 106 patients, the mean age was 55.9 ± 16.9 years. 64.2% were men, and 35.8% were women. Considering each patient's bilateral anatomy, the reported 70.28% (149/212) frequency of EICA variations of all arteries. Tortuosity, kinking, and coiling variation were found in 61.8%, 4.2%, and 4.2% of arteries, respectively. Also, 54.72%, 1.89%, and 0.94% of the participants had bilateral tortuosity, kinking, and coiling, respectively. There was a significant relationship between the prevalence of EICA variations and female sex, age, and hypertension. CONCLUSION: The frequency of EICA variations in arteries and patients was 70.28% and 73.58%, respectively. Tortuosity was the most common variation. Female sex, old age, and hypertension were significant risk factors for EICA variations.

Critical Circulatory Failure Accompanied With the aVR Sign Caused by Severe Graft Kinking Related to Acute Pseudoaneurysm Formation After Type A Acute Aortic Dissection Repair.

The aVR sign characterized by ST-segment elevation in lead aVR and diffuse ST-segment depression on the electrocardiogram indicates potential life-threatening conditions. We report the case of a 53-year-old male with a history of ascending aortic replacement for acute aortic dissection, who presented to our institution in shock. The initial electrocardiogram revealed the aVR sign, consisting of ST-segment elevation in lead aVR and ST-segment depression in leads II, III, aVF, and V3-6, leading to the initiation of salvage veno-arterial extracorporeal membrane oxygenation (ECMO) due to deteriorating hemodynamics. The aVR sign resolved shortly after ECMO initiation, and hemodynamics stabilized even with reduced ECMO flow. Subsequent coronary angiography showed no impaired coronary perfusion, whereas contrast-enhanced CT revealed severe supra-valvular stenosis due to pseudoaneurysm-induced graft kinking. The patient was then managed with emergency surgery for the pseudoaneurysm. In this report, we encountered a salvaged case of critical circulatory failure presenting with the aVR sign due to severe graft kinking caused by pseudoaneurysm formation.

The female urethral closure mechanism during physical stress.

The closure of the urethra under the condition of stress is the result of a reflex contraction of the urethral rhabdosphincter and pelvic floor muscles. This is likely induced by activity of the abdominal muscles due to a sudden increase in abdominal pressure. This reflex contraction with an increase of urethral pressure occurs a few milliseconds before an increase in intraabdominal pressure. The urethral pressure increase during stress is only possible with fixation of the urethra by the pubourethral ligaments (PUL), facilitating urethral kinking. The highest and most important increase in pressure and resistance occurs in the distal urethra due to this kinking of the urethra.

Entrapment of the Subscapular Artery between the Radial Nerve and the Posterior Wall of the Axilla: An Anatomical Variation with Clinical Significance.

OBJECTIVE: The subscapular artery vascularizes a substantial region of the thoracic wall, and the significance of its distribution is well depicted in the diversity of reconstructive procedures that rely on its blood supply. The aim of this study is to present an uncommon anatomical variation of the artery and discuss the clinical implications of its presence. CASE REPORT: This case report depicts a rare variant of compression and the kinking of the subscapular artery by the radial nerve on the posterior wall of the axilla that was encountered during dissection of a male cadaver of Greek origin. CONCLUSION: The use of autologous tissues in the reconstruction of defects and treatment of lymphedema is expanding, so the need to establish safer surgical dissections is also becoming more apparent. The case of entrapment of the subscapular artery by the radial nerve is extremely rare, however, utilizing tissues perfused by this artery for reconstructive purposes could potentially be futile and unsuccessful due to the inadequate blood supply or vessel thrombosis. Hence, the surgeon should adapt the treatment plan according to preoperative findings, as the presence of anatomical variants should always be suspected.

Five-Year Experience of Interwoven Self-Expanding Stent Implantation in Stenotic Kinking of Below the Knee Prosthetic Bypasses.

PURPOSE: The purpose of this study was to evaluate the 5-year real-world results of Supera stent implantation in below the knee prosthetic bypasses (BKPBs). All the procedures were performed because of a history of recurrent thrombosis of the graft and significant stenotic kinking of the prosthesis during knee flexion. A Supera stent was implanted to prevent the next potential BKPB thrombosis. MATERIALS AND METHODS: Fourteen patients were included in this single-center, retrospective observational cohort study. All patients underwent Supera stent implantation in infrainguinal prosthetic bypass between 2012 and 2017, due to a history of recurrent thrombosis and kinking of the prosthetic bypass. RESULTS: Prior to Supera stent implantation procedure, all the patients had more than one episode of acute limb ischemia caused by thrombosis of the BKPB. The median number of BKPB thromboses prior to Supera stent implantation was 3 and ranged from 2 to 6. Technical success was achieved in all cases. Primary patency rates at 12, 24, 36 and 60 months were 71.4%, 57.1%, 57.1% and 14.3%, respectively. Secondary patency rates at 12, 24, 36 and 60 months were 78.6%, 64.3%, 64.3% and 35.7%, respectively. One stent fracture was reported during 60-month follow-up. Major amputation was performed in 6 patients in 5-year follow-up. CONCLUSION: Supera stent in treatment of recurrent thrombosis of BKBP is a safe procedure with acceptable mid-term results. However, larger and comparable prospective studies are needed for broader analysis of this procedure.

An optimized framework for prediagnosis of diabetic retinopathy using HHO-CBL model.

BACKGROUND: Diabetic Retinopathy (DR) is a widespread intense stage of diabetes mellitus that causes vision-effecting anomalies in the retina. It is a medical health condition on the strength of fluctuating glucose level in the blood that can result in vision loss in case of severity. OBJECTIVE: As a result, early detection and treatment with DR is the most significant task which will tremendously reduce the likelihood of vision impairment and is still a difficult challenge. Many conventional methods fail to detect primary causes of formation of Microaneurysms, that are used to determine the Prediagnosis of DR. METHOD: To overcome this challenge, the proposed model incorporates Harris Hawk Optimization with CNN-Bi-LSTM (HHO-CBL) to extract the features. The Prediagnosis of DR has been achieved through this model by spotting saccular dilations, hyaline like material in the capillary aneurysm wall, kinking of vessels since these are the indications for the creation of microaneurysms that are spotted in the blood vessel of the retina. The recommended model is also used to automatically detect DR and its progression in many phases. Furthermore, in order to identify the severity of DR retina, we used a benchmark Kaggle APTOS dataset to train the HHO-CBL model. RESULTS: Experimental results reveal that this model obtains the best classification accuracy of 96.4 % for an early diagnosis and 98.8 % for a five-degree classification. In addition to those results, a comparison with previously carried out studies has also shown that this model provides a promising solution for a successful Prediagnosis of DR and its staging. CONCLUSIONS: In the current research, an innovative HHO-CBL was developed for identifying the primary causes that lead to the formation of microaneurysms and diagnosing all five grades of DR. According to the acquired results presented through the evaluation performance metrics indicates that the pre-early diagnosis and five grade classification using feature embedding technique outperformed the other prevailing approaches (Tab. 4, Fig. 10, Ref. 31).

Reshaping Covalent Nanowires by Exploiting an Unexpected Plasticity Mediated by Deformation Twinning.

Nanowires (NWs) are among the most studied nanostructures as they have numerous promising applications thanks to their various unique properties. Furthermore, the properties of NWs can be tailored during synthesis by introducing structural defects such as nano-twins, periodic polytypes, and kinks, i.e., abrupt changes in their axial direction. Here, this work reports for the first time the postsynthesis formation of such defects, achieved by exploiting a peculiar plasticity that may occur in nanosized covalent materials. Specifically, in this work the authors found that single-crystal CuO NWs can form double kinks when subjected to external mechanical loading. Both the microscopy and atomistic modeling suggest that deformation-induced twinning along the ( 1 ¯ 10 ) $( {\bar{1}10} )$ plane is the mechanism behind this effect. In a single case the authors are able to unkink a NW back to its initial straight profile, indicating the possibility of reversible plasticity in CuO NWs, which is supported by the atomistic simulations. The phenomenon reported here provides novel insights into the mechanisms of plastic deformation in covalent NWs and offers potential avenues for developing techniques to customize the shape of NWs postsynthesis and introduce new functionalities.

Hemolytic Anemia Caused by Graft Kinking Following Ascending Aortic Replacement: Endovascular Treatment With a Palmaz XL Stent.

A 66-year-old man presented with hemolytic anemia, which required frequent blood transfusion, 6 months after surgical repair of an ascending aortic pseudoaneurysm. Hemolysis was attributed to luminal stenosis caused by graft kinking by laboratory test, CT and four-dimensional magnetic resonance imaging. First, an Excluder cuff was placed at the stenotic site under rapid pacing, but it migrated distally. Thereafter a Palmaz XL stent was placed at the stenotic site, which led to resolution of anemia. In this case, a Palmaz XL stent was successfully used to treat hemolytic anemia caused by graft kinking following ascending aortic surgery.

Characterization of Failure Behavior in Unidirectional Fiber-Reinforced Polymer via Off-Axis Compression on Small Block Specimens.

An experimental investigation was focused on the failure behavior of unidirectional fiber-reinforced polymers when subjected to combined longitudinal/transverse compression and in-plane shear due to off-axis loading. Block-shaped and end-loaded specimens, spanning ten different fiber orientations (0°, 5°, 10°, 15°, 20°, 30°, 45°, 60°, 75°, and 90° with respect to the loading direction), were loaded to ultimate failure using a dedicated fixture. Different failure modes, including longitudinal compression, in-plane shear, and transverse compression, were identified, along with distinctive characteristics of the corresponding failure envelopes. Four physically based failure theories-Hashin, Camanho, Puck, and LaRC05-were subjected to a comparative analysis. Criteria derived from the concept of the action plane consistently outperformed in describing matrix-dominated failures, providing both qualitative and quantitative predictions of failure stresses and fracture plane orientation. However, for fiber-dominated failures, these theories seem to fall short in providing satisfactory predictions, particularly in accurately describing the influence of shear on fiber compression failure. Although criteria based on fiber-kinking theory can reasonably explain the formation of kink bands, they tend to yield overly conservative results. Recalibrations and minor refinement based on experimental results were implemented, leading to an improved agreement. Finally, the constructive role of off-axis compression tests in characterizing the failure behavior of unidirectional composites is discussed.

Association between internal carotid artery kinking and ischemic stroke: A population-based cross-sectional study.

AIM: Evidence for an association between Internal carotid artery (ICA) kinking and ischemic stroke has been controversial. We aimed to examine the association between ICA tortuosity and risk of ischemic stroke and specific ischemic stroke subtypes (large artery atherosclerosis, LAA; small artery occlusion, SAO). METHODS: A total of 419 outpatients were included in this cross-sectional study. ICA kinking was objectively assessed by head and neck computed tomography angiography (CTA). The risk of ischemic stroke for each patient was evaluated according to the Essen Stroke Risk Score (ESRS). Ischemic stroke subtypes (LAA and SAO) were measure with head magnetic resonance imaging (MRI). RESULTS: The average age of patients was 59.1 years (SD = 13.25) and 264 (63.0 %) were males. The prevalence of ICA kinking in this sample was 31.5 % (132 out of 419). Individuals with ICA kinking was associated with 0.55-points increase in ESRS score than those without ICA kinking (95 % CI, 0.28-0.81, p < 0.001) among patients over 50 years. In addition, right ICA kinking or left ICA kinking were associated with 0.35-points (95 % CI, 0.08-0.63) and 0.49-points (95 % CI, 0.23-0.76) increase in ESRS score, respectively. For specific ischemic stroke subtypes, individuals with ICA kinking had a 10.34-fold increased risk of SAO compared to those without ICA kinking (95 % CI, 6.22-20.68). Individuals with right ICA kinking had a 4.51-fold risk of SAO than those without kinking (95 % CI, 2.64-7.71), and had an 8.86-fold risk of SAO than those without kinking in the left ICA kinking (95 % CI, 4.97-15.79). CONCLUSION: Our findings support the role of ICA kinking on ischemic stroke. Early screening and proper treatment of carotid artery tortuosity could be a potential intervention strategy for the prevention of ischemic stroke later on.

Endovascular straightening of the internal carotid artery during mechanical thrombectomy: The "tightrope technique".

Mechanical thrombectomy is a standard treatment for acute stroke, but it can be technically challenging in elderly patients with difficult vascular anatomy. To overcome this issue, we propose a new endovascular approach called the "tightrope" technique. This technique uses a stiff guidewire and a standard angiographic catheter to straighten the internal carotid artery (ICA) tortuosity, allowing the guiding catheter to be positioned next to the intracranial level. We retrospectively evaluated all the procedures in which the "tightrope" technique was used. This approach involves advancing a 0.035″ Advantage stiff guidewire and a standard 4 Fr angiographic catheter through the vascular tortuosity. The catheter is twisted over the guide wire in a clockwise direction, gaining tension that gradually straightens the vascular axis, allowing the guiding catheter to pass up to the distal ICA. Between June 2022 and March 2023, we successfully performed consecutive mechanical thrombectomy procedures using the tightrope technique in 11 patients with highly tortuous ICA segments. In all cases, we were able to safely advance the catheter system up to the distal cervical ICA. Although our study included a small cohort of patients, the "tightrope" technique proved to be successful in all patients, allowing for safe advancement of the guiding catheter toward extremely tortuous anatomy. However, further validation in a larger patient population is necessary to determine the technique's effectiveness and safety profile.

Right coronary artery kinking after tricuspid valve annuloplasty: a case report.

Background: Right coronary artery (RCA) injury is a rare complication of valvular surgery. However, complications should be considered, due to the significant clinical consequences. Identifying the coronary injury type and understanding the underlying pathophysiological mechanisms is essential to managing these complications. Case summary: The case of a 59-year-old man who underwent conservative mitral valve surgery with tricuspid valve annuloplasty is presented. The early post-operative period was complicated by acute coronary syndrome with inferior persistent ST-segment elevation. A coronary angiogram confirmed critical RCA hazy lesions, raising the suspicion of coronary kinking. To confirm the underlying mechanism for these lesions and determine the best treatment strategy, endocoronary imaging was performed, revealing coronary kinking of the RCA. Based on the persistent acute ischaemia, a long-lasting drug-eluting stent (DES) was implanted in the lower and upper knees of the RCA. After angioplasty, electrocardiography showed regression of the ST-segment elevation. Ten days later, coronary angiography and optical coherence tomography showed good results. The patient recovered from his myocardial infarction. Discussion: Only a few reports describe the use of endocoronary imaging for diagnosing coronary artery injury after tricuspid annuloplasty. The variety of lesion types that could underlie a single post-operative myocardial infarction makes endocoronary imaging a relevant technique to guide management strategy and optimize DES implantation.

Patient-specific stent for hemolytic anemia due to a kinked ascending aortic graft.

Hemolytic anemia after thoracic aortic surgery is rare. A 69-year-old female patient, who underwent ascending aorta replacement for acute type A aortic dissection 7 years ago, was transferred from another hospital due to hemolytic anemia necessitating regular blood transfusions. After engaging in interdisciplinary discussions, we ruled out alternative medical diagnoses and treatments, ultimately identifying the kinked aortic graft as the primary cause of hemolysis. Due to the patient's comorbidity, it was deemed high-risk to perform a redo thoracic aorta surgery for the replacement of the kinked aortic graft. Therefore, we decided to insert a patient-specific bare-metal stent into the kinked aortic graft to alleviate the kinking and promote improvement in hemolysis. We decided to perform the stent procedure under local anesthesia. The bare-metal stent was designed to be approximately 15% larger than the size of the pre-existing kinked aortic graft. A stent measuring 32 mm × 80 mm was successfully inserted and ballooned within the patient's ascending aortic graft. As a result, the patient's hemolytic condition showed gradual improvement over time. In this way, we aim to share our experience of inserting a patient-specific bare-metal stent under local anesthesia in patients who exhibit mechanical hemolysis due to a kinked aortic graft, especially when redo surgery is considered high-risk.

The effectiveness of chest T-tube drainage in uniportal video-assisted thoracic surgery.

OBJECTIVES: Uniportal incision located at 4th or 5th intercostal space represents a problem for the correct drainage of distal areas of pleural cavity. The T-shaped tube can drain both the extremities of pleural space. In this study, we evaluated the effectiveness of T-chest tube compared to classic chest tube after uniportal video-assisted thoracic surgery. METHODS: We compared the effectiveness of T-tube and classic 28 CH chest drainage after different surgical procedures in uniportal video-assisted thoracic surgery: lobectomies, wedge resections and pleural and mediastinal biopsies. As primary end points, drained effusion and evidence of pneumothorax at postoperative day 1, subcutaneous emphysema, tube kinking, obstruction and necessity of repositioning or postoperative thoracentesis were considered. Pain at 6 and 24 h after surgery, pain at tube removal and mean hospitalization were analysed as secondary end points. RESULTS: A total of 109 patients were selected for the study, 51 included to the T-tube group while the other 58 ones to the control group with classic drainage. Patients with T-tube showed a significantly lower rate of pneumothorax (29.4% vs 63.8%; P < 0.001), tube kinking (5.9% vs 27.6%; P = 0.003) and need of repositioning (2.0% vs 12.1%; P = 0.043). No significant results were obtained in subcutaneous emphysema (P = 0.26), tube obstruction (P = 0.32), drained effusion (P = 0.11) and need of postoperative thoracentesis (P = 0.18). Patients with T-tube complained of <6 h after surgery (P < 0.001). Conversely, T-tube removal was reported to be more painful (P < 0.001). CONCLUSIONS: Chest T-tube can achieve significantly lower rate of postoperative pneumothorax, kinking and repositioning with less pain 6 hours after surgery compared to classic tube.

Impact of lock solutions on the mechanical performance of polyurethane central venous catheters: A comparative study.

The impact of ethanol locks on the mechanical performances of central venous catheters was compared to that of aqueous-based locks. Several mechanical tests were performed to evaluate catheter behavior: kinking radius measurements, burst pressure, and tensile tests. Different polyurethanes were studied to assess the impact of radio-opaque charge and polymer chemical composition on catheter behavior. The results were correlated to swelling measurements and calorimetric measurements. In particular, ethanol locks have a higher impact on long contact time than aqueous-based locks: stresses and strains at break were lower, and kinking radii were higher. However, for all catheters, the mechanical performances remain much higher than the normative requirements.

Delayed rupture of the iliac artery after endovascular therapy.

Iliac artery rupture during endovascular therapy (EVT) is a life-threatening complication requiring prompt diagnosis and treatment. However, delayed rupture of the iliac artery after EVT is rare, and its predictive value remains unknown. Herein, we present the case of a 75-year-old woman who developed delayed iliac artery rupture 12 h after balloon angioplasty and placement of a self-expandable stent in the left iliac artery. Hemostasis was achieved with a covered stent graft. However, the patient died of hemorrhagic shock. From the review of previous case reports and the pathological findings of the current case, increased radial force due to overlapping stent and kinking of the iliac artery may be associated with delayed iliac artery rupture. Learning objective: Delayed iliac artery rupture after endovascular therapy is rare but with a poor prognosis. Hemostasis can be achieved using a covered stent; however, the outcome could be fatal. Based on pathological findings and previous case reports, increased radial force at the stent site and kinking of the iliac artery may be associated with delayed iliac artery rupture. Self-expandable stent probably should not be overlapped at the site where kinking is likely to occur, even if long stenting is needed.

Tortuous Carotid Arteries and Their Clinical Implications: A Report of Two Cases.

The tortuous carotid artery is a rare anatomic abnormality defined as vascular elongation leading to an altered course. It can be discovered incidentally or have clinically significant manifestations. The most common location is the internal carotid artery or, less commonly, the common carotid artery. Bilateral tortuous carotid arteries can also occur, leading to "kissing carotids" where the carotid arteries are juxtaposed. We describe two cases of carotid artery tortuosity in patients with risk factors associated with its development. One case is of a 91-year-old female presenting with a cerebrovascular accident and an incidental finding of tortuosity of the right common carotid artery mimicking the appearance of "kissing carotids." The other case concerns a 66-year-old female with a symptomatic tortuous left internal carotid artery. This report aims to inform clinicians of the differences in the anatomical features, pathogenesis, and possible clinical implications of these variants.

Rare Dilated Collateral Circulation from Accessory Meningeal Artery to Inferolateral Trunk: A Case Report.

The accessory meningeal artery (AMA) demonstrates various potential anastomoses with the external (ECA) and internal (ICA) carotid arteries. However, rarely does the AMA markedly dilate and compensate for ICA blood flow. A 52-year-old woman with nonspecific symptoms was diagnosed with multiple cerebral aneurysms and abnormal blood vessels observed on magnetic resonance angiography. Digital subtraction angiography revealed four aneurysms and anastomoses between the left AMA and inferolateral trunk (ILT). In addition, two sequential severe flexions were observed in the cervical portion of the left ICA. No ischemic lesions were detected on magnetic resonance imaging. In conclusion, we experienced a rare case in which the AMA-ILT anastomosis was highly developed. This case also presented with the unusual characteristics of an anomaly in the extracranial ICA and multiple aneurysms.