324 Unilateral pulmonary artery agenesis with controlateral embolism: a double vascular trouble

Methods and results A 60-year-old male patient underwent coronary angiography (CA) for a non-ST segment elevation myocardial infarction (NSTEMI). CA revealed significant multivessel disease. Both internal mammary arteries (AMI) were patent, with right IMA markedly larger than the left IMA. The exam revealed also an abnormal branch arising from the proximal right coronary artery extending backwards, likely to the right lung. Pre-operative chest radiograph demonstrated asymmetry of the two hemithoraces with slight elevation of the right hemidiaphragm, small ipsilateral lung, and mediastinal shift towards the right. The patient underwent urgent CABG surgery. Myocardial revascularization was successfully performed using both AMI and one saphenous vein segment. The postoperative course was complicated by respiratory failure requiring prolonged mechanical ventilation. A chest computed tomography angiography was performed, revealing complete absence of the right pulmonary artery and a left lower lobe segmental pulmonary embolism. Furthermore, blood in the hypoplastic right lung was supplied by multiple collaterals arising from RCA and right IMA. Intravenous heparin was started with clinical improvement. Two weeks later, a lung scintigraphy was performed, ruling out perfusion defects. The patient was discharged home on oral anticoagulation with warfarin. Conclusions Unilateral pulmonary artery agenesis (UPAA) is an uncommon congenital anomaly of the great vessels. Despite the absence of the pulmonary artery, blood supply of ipsilateral lung is provided by systemic collaterals originating from bronchial, intercostal, internal mammary, and sub-diaphragmatic arteries. More rarely, these collaterals may arise from the coronary arteries with different implications, ranging from asymptomatic condition to myocardial ischaemia and infarction. In our case, the condition was previously asymptomatic. The occurrence of pulmonary embolism contributed to worsen the ventilation–perfusion mismatch, explaining the respiratory failure during the postoperative period.

Trans-radial percutaneous intervention for thrombosed hemodialysis access: A single-center experience

Background: Traditionally, percutaneous transluminal angioplasty (PTA) is a first-line approach for stenosed dialysis accesses and has been performed through the non-thrombosed vein segment. For thrombosed accesses, thrombectomy (whether open or percutaneous) is a standard approach. The primary objective of our study is to determine the clinical and technical outcomes of the trans-radial approach of PTA among thrombosed dialysis accesses, in terms of safety and feasibility, technical and clinical aspects and factors influencing them, as well as assisted primary patency, secondary patency at 6 and 12 months. Methods: This is a single-center retrospective study that included 150 patients over 3 years. About 123 patients underwent successful percutaneous balloon angioplasty through the radial access. Results: We report an overall technical and clinical success rate of 82%, assisted primary patency rate of about 90.25% at 3 months, 82.93% at 6 months, 73.18% at 1 year, and secondary patency rate of 94% at 1 year. Twenty-seven patients were referred for surgical revisions/creation of a new fistula for reasons like inability to pass wire (6 patients), unfavorable anatomical variations like aneurysms at the proximal segments (5 patients), inability to cross the fistula (5 patients), and persistent fistula dysfunction with no flow after initial balloon dilatation (11 patients). Three patients had hematoma at the radial access site (2.5%) while two patients had the AV fistula segment rupture and were successfully treated conservatively. Conclusion: We conclude that PTA through the trans-radial approach to completely thrombosed hemodialysis accesses is a good alternative to transvenous access and has a very good assisted primary patency and secondary patency at 1 year without major complications.

Novel external stenting for reconstruction of high flow arteriovenous fistula

Background: High-flow arteriovenous fistulae (HF-AVF) may lead to adverse cardiac remodeling in hemodialysis patients. We have investigated whether a novel external stent is safe and effective in reducing and stabilizing flow rates during a 1-year follow-up after HF-AVF reconstruction. Methods: All patients with HF-AVF (access flow rate ⩾ 1500 ml/min), who underwent HF-AVF reconstruction with external stenting in two centers between June 2018 and May 2020, were included in this retrospective analysis. During HF-AVF reconstruction, the dilated vein segment was resected, underwent volume reduction, and was externally stabilized using a braided cobalt-chromium external stent. AVF flow rates were assessed preoperatively, intraoperatively, and at follow up visits using duplex ultrasound. Results: Forty-three HF-AVFs in 42 patients were reconstructed and supported with an external stent (mean age 49 years, range 20–86 years; 74% men). Fifty-one percent were forearm AVFs, 49% were upper arm. The mean preoperative flow rate was 2622 ± 893 ml/min (range: 1500–6000 ml/min) and was decreased to 710 ± 221 ml/min (range: 300–1300 ml/min) intra-operatively after HF-AVF reconstruction. At 6 and 12-months follow-up, the mean flow rates were 1132 ± 320 ml/min (range: 470–1700 ml/min) and 1453 ± 888 ml/min (range: 300–3800 ml/min), respectively. Recurrence of high flow (>1500 ml/min) occurred in 16% and 25% of the patients at 6 and 12 months and primary patency rates were 86% and 70%, respectively. Conclusions: This early experience with novel external stenting for HF-AVF reconstruction demonstrates that it is a safe and effective method for reducing and stabilizing flow rates up to 1-year post procedure. Additional studies are required to evaluate the durability of this procedure over the longer term and assess its effect on cardiac remodeling.

Computed tomography venography versus intravascular ultrasound in the diagnosis of iliofemoral vein stenosis

Summary: Background: Iliofemoral vein stenosis can cause debilitating chronic venous disease. Diagnostic tools include both computed tomography venography (CTV) and intravascular ultrasonography (IVUS). We aim to compare the diagnostic performance of CTV and IVUS. Patients and methods: We performed a retrospective study of patients with chronic venous disease presenting with iliac vein compression or post-thrombotic limb symptoms, excluding those with acute deep vein thrombosis, high anaesthesia risk, or who had contrast allergy. All patients received CTV before IVUS, as part of the diagnostic work-up and intervention. The cross-sectional area (CSA) of iliofemoral vein segments obtained from both studies were compared against reference CSAs to derive percentage stenosis. A 50% reduction in CSA was considered significant. Results: We studied 50 patients between May 2018 and April 2019. 58% of patients had severe disease CEAP C5-6. 48% of patients had at least one vein segment with significant stenosis. The left proximal common iliac vein was the most commonly stenosed vein segment (n = 12, 24% on IVUS). CSA measurements from CTV were greater than those of IVUS, with a correlation coefficient of 0.57 (p < 0.005). Conversely, percentage stenosis measured on CTV was lower than on IVUS, with approximately one-third of significant stenosis missed on CTV (58 veins from CTV vs. 78 from IVUS, p < 0.005). With IVUS as the gold standard, CTV has low sensitivity (37.2%, 95% CI 26.5–48.9) and high specificity (92.5%, 95% CI 89.3–94.9) in detecting significant stenosis. Conclusions: CTV has limited diagnostic performance in identifying iliofemoral vein stenosis. Patients with normal CTV findings should proceed with IVUS imaging if the clinical features are supportive of iliofemoral vein stenosis.

Nitinol stent–assisted maturation of the dysfunctional cannulation zone in the immature arteriovenous fistula

Introduction: The native arteriovenous fistula may remain immature despite adequate arterial inflow after formation. This may occur when the puncturable vein segment (cannulation zone) is too small to be reliably punctured, occluded or too deep under the skin for needle access. We performed stenting (stent-assisted maturation) of arteriovenous fistulas with an immature cannulation zone, allowing for a large subcutaneous channel which could then be immediately punctured for dialysis. Methods: We performed a retrospective review of 49 patients (mean age was 58.7 ± 16.09 (12–83) years, mean arteriovenous fistula age of 162.6 ± 27.28 days) with end-stage renal failure who underwent balloon dilatation and bare-metal stent implantation (1.6 ± 0.67 (1–3) stents, median diameter and length of 8 (5–14) mm and 80 (40–150) mm, respectively) through their cannulation zone (forced maturation). Radiocephalic (35 arteriovenous fistulas), brachiocephalic (10 arteriovenous fistulas) and autogenous loop arteriovenous fistulas (4 arteriovenous fistulas) were included with 30 patients (61.2%) having an inadequate cannulation zone venous diameter, 9 patients (18.4%) having an absent cannulation zone and 10 patients (20.4%) having a patent cannulation zone deeper than 1 cm which was not reliably puncturable. The study was conducted over 9 years (January 2008–December 2016) with implantation of the SMART® stent and Absolute Pro® stent in 61.2% and 38.8%, respectively. Long-term outcomes including primary useable segmental and access circuit patency as well as assisted primary access circuit patency, rate of re-intervention, technical success and complications were analysed. Results: At 6 months, 12 months and 4 years, respectively, cannulation zone primary patency was 84.4%, 74.4% and 56.1% and access circuit primary patency was 62.2%, 45.3% and 23.2%; however, assisted primary access circuit patency was 95.6%, 91.1% and 83.8%, achieved with an endovascular re-intervention rate of 0.53 procedures/year with only four thrombosed circuits occurring. Discussion: Forced maturation using nitinol stents allows for long-term haemodialysis access with a low rate of re-intervention.

Variants of Localization and Extension of Hypo- and Aplasia of the Great Saphenous Vein in Patients with Primary Varicose Great Saphenous Veins

The objective of the research was to improve the diagnostics and treatment of patients with primary varicose great saphenous veins by studying their frequency and systematizing the variants of localization and extension of great saphenous vein hypoplasia and aplasia in its trunk. Materials and Methods. The study included 560 patients with varicose veins of the lower limbs and pathological refluxes in different segments of the great saphenous vein. All the patients underwent triplex ultrasound scan of the lower limb venous system. Results. Among the patients with pathological reflux in a certain GSV segment, hypo- and aplasia of its segments were observed in 32.5% of the cases (95% CI 28.6-36.6%). Aplasia of this vein was observed twice as less frequently than hypoplasia (p<0.05). In 2.3% of the cases (95% CI 1.2-3.9%), hypoplasia of a certain GSV segment evolved to aplasia, or vice versa. It was found that the GSV trunk may have several hypo- or aplastic regions separated by its normal or varicose segment – bi-level hypo- or aplasia that was observed in 3.8% of the patients with hypo- or aplasia (95% CI 1.6-7.8%). In bi-level hypo- or aplasia, 2 hypoplastic regions were detected in 85.7% of the cases (95% CI 42.1-99.6%) and 2 aplastic regions were found in 14.3% of the cases (95% CI 0.4-57.9%). There were proposed to distinguish the following variants of GSV hypo- and aplasia: 1) simple: total, proximal, segmental and distal; 2) bi-level: proximal segmental, distal segmental and bi-segmental. In addition, for every dysplastic vein segment, the type of malformation should be indicated, namely hypoplasia, aplasia, or hypo/aplasia. Conclusions. The study conducted allowed assessing the relationship between the variants of GSV hypo- and aplastic segment localization and extension and different variations of pathological refluxes of the GSV in its trunk for further choice of surgical tactics.

Arteriovenous Fistula Is a Rare but Significant Finding After Endovenous Thermal Ablation

Endovenous thermal ablation (EVTA) has become the mainstay of treatment for symptomatic varicose veins in the setting of saphenous vein insufficiency. We observed 5 iatrogenic arteriovenous fistulas (AVFs) following thermal ablation of the great saphenous vein (GSV). Postprocedure duplex ultrasound (DUS) results were analyzed for the presence of AVF in any location along or adjacent to the treated saphenous veins. Cases were prospectively followed. English literature was reviewed for any other published reports of AVF after EVTA. Data were compiled using our 5 cases, 2 cases were shared with us by colleagues and 20 cases were reported in the literature. Our center has performed more than 4000 (4155) cases of EVTA over the past 15 years. Five cases of AVFs were detected, 3 were found in asymptomatic patients during routine post-EVTA surveillance. The additional 2 cases presented with signs or symptoms which prompted a DUS after ablation. Including cases in the literature, we were able to identify 2 different types of AVFs. The first type of AVF was demonstrated in 13 cases where the AVF occurred along the treated vein. All of these cases involved ablation of the GSV and 90% of these showed signs of recanalization. The second type of AVF was seen in 14 additional cases where the AVF involved a vein segment adjacent to or remote from the ablated vein. The second type occurred in the GSV in 5 cases, external iliac vein (EIV) in 3 cases, and in the popliteal vein in 5 cases. There is 1 reported case of AVF involving the sural artery after perforator vein EVTA. Three of the type 1 cases were followed and spontaneously resolved; 3 of the type 1 cases were treated with surgical ligation with unreported outcomes. Seven cases did not report any follow-up information. Seven of the type 2 cases were treated, and had spontaneous resolution and 7 were not treated. The follow-up on these cases ranged from 1 month to 6 years. Thermal ablation can result in AVF either along the length of the treated vein or adjacent to the area of ablation. Further study would help elucidate the cause and treatment algorithms.

The Role of Tomographic Ultrasonography in Conduit Mapping before Coronary Artery Bypass Grafting

Objective. To assess the performance of tomographic ultrasonography (TUS) in providing images that will enable optimum choice of vein segment to harvest for coronary artery bypass grafting (CABG). Methods. This was a prospective study of diagnostic accuracy. The index test was tomographic ultrasonography. The reference standard was intraoperative observation. The study was performed at the Vascular Imaging and Cardiothoracic Department at Wythenshawe Hospital, Manchester. Patients undergoing CABG who require vein mapping were included in the study. The main outcome measures were the number of tributaries identified in harvested vein segments, presence of varicosities, and usable length of vein. Results. The TUS correctly identified 89 out of 111 vein tributaries in 10 patients resulting in a sensitivity of 80.2%. This resulted in a p value of 0.000001 using an exact binomial test, with a prior probability of 0.5. TUS had a sensitivity of 66.7% and a specificity of 100% in the identification of varicosities over 14 patients. TUS had 90% agreement with intraoperative observation in assessing usable length of vein over 14 patients. Conclusions. Our results show that TUS has a high sensitivity in identifying vein tributaries. This can be used to select veins with fewer tributaries for harvesting should TUS be used for preoperative vein mapping before CABG.