Straight Graft Research Articles

Effect of graft sizing in valve-sparing aortic root replacement for bicuspid aortic valve: The Goldilocks ratio

ObjectiveTo investigate the effect of graft sizing on valve performance in valve-sparing aortic root replacement for bicuspid aortic valve. MethodsIn addition to a diseased control model, 3 representative groups—free-edge length to aortic/graft diameter (FELAD) ratio <1.3, 1.5 to 1.64, and >1.7—were replicated in explanted porcine aortic roots (n = 3) using straight grafts sized respective to the native free-edge length. They were run on a validated ex vivo univentricular system under physiological parameters for 20 cycles. All groups were tested within the same aortic root to minimize inter-root differences. Outcomes included transvalvular gradient, regurgitation fraction, and orifice area. Linear mixed effects model and pairwise comparisons were employed to compare outcomes across groups. ResultsThe diseased control had mean transvalvular gradient 10.9 ± 6.30 mm Hg, regurgitation fraction 32.5 ± 4.91%, and orifice area 1.52 ± 0.12 cm2. In ex vivo analysis, all repair groups had improved regurgitation compared with control (P < .001). FELAD <1.3 had the greatest amount of regurgitation among the repair groups (P < .001) and 1.5-1.64 the least (P < .001). FELAD <1.3 and >1.7 exhibited greater mean gradient compared with both control and 1.5 to 1.64 (P < .001). Among the repair groups, 1.5 to 1.64 had the largest orifice area, and >1.7 the smallest (P < .001). ConclusionsFor a symmetric bicuspid aortic valve, performance after valve-sparing aortic root replacement shows a bimodal distribution across graft size. As the FELAD ratio departs from 1.5 to 1.64 in either direction, significant increases in transvalvular gradient are observed. FELAD <1.3 may also result in suboptimal improvement of baseline regurgitation.

Effects of Cutting Planes on Costal Cartilage Warping.

Autogenous costal cartilage becomes a favorable choice for nasal reconstruction and complicated aesthetic rhinoplasty, due to its ample supply, sufficient for most patients. However, a notable drawback is the potential for warping. Our study aims to identify cutting planes that minimize warping. Two hundred and seven costal cartilage grafts were obtained by slicing the extracted costal cartilages from 10 fresh cadavers, along three main planes: cephalocaudal, anteroposterior, and parallel to the synchondrosis plane. Each of these major planes was further divided into grafts taken from both the central and peripheral portions. Furthermore, both subgroups were categorized into three thicknesses: 1mm, 2mm, and 3mm. The warping angles of all grafts were then compared at various time intervals after the initial cutting. Cephalocaudal cuts exhibited significantly greater warping than other planes. Anteroposterior cuts displayed the least warping, although this difference lacked statistical significance. Peak warping occurred at 30 minutes. Certain grafts continued to warp even at 1 month. Central grafts had less warping than peripheral ones, though not statistically significant. Cephalocaudal cuts yielded the highest warping angle. Surgeons seeking thin (< 3 mm) straight grafts should opt for anteroposterior or parallel to synchondrosis planes. Thicker grafts (> 3 mm) can be cut in the cephalocaudal plane with an acceptable warping angle, close to parallel with the synchondrosis plane. For curved cartilage, thin cephalocaudal cut is recommended. Additionally, we suggest placing the cartilage in normal saline for at least 30 minutes, allowing for maximum warping to occur.

Long-Term Results After Aortic Valve Replacement with Last-Generation Stentless Prostheses.

The purpose of this study was to evaluate the long-term clinical and hemodynamic results in patients affected by severe aortic valve disease after aortic valve replacement with third-generation stentless aortic prostheses (3F® stentless equine pericardial [Medtronic plc, Minneapolis Minnesota] and Pericarbon Freedom™ stentless bovine pericardial [LivaNova plc, London, United Kingdom]) and to analyze the benefits and the drawbacks associated to their use. Between June, 2003 and Sept, 2015 a cohort of 548 consecutive patients affected by aortic valve disease received an aortic valve replacement using a last-generation stentless pericardial aortic prosthesis at our unit. Respectively, 322 patients received a Pericarbon Freedom™ and 226 received a 3F® aortic valve. Size ranged between 19 and 29, with prevalence of 23 and 25 devices. Mean age at operation was 71± 11 years, 57% of patients were males, the mean logistic EuroScore was 8.9 ± 7.2 and 44.2% received concomitant procedures. The mean extracorporeal circulation (ECC) time was 119.2 ± 40.6. The mean cross clamp time was 90.5' ± 21.4'. In 30 patients, the aortic prosthesis was included in a Dacron tube straight graft for a Bentall operation. Early/in-hospital mortality was 2.55% (14 cases) for the entire cohort. In patients receiving isolated aortic valve replacement (AVR), it was 0.91% (5 cases). Follow up ranged between six months and 12 years (median follow-up time: 6.77 years). During follow up, 137 patients died of all causes (25%), of whom 32 patients died of cardiac causes (5.8%). Cardiac survival probability was 91% at 12 years. All surviving patients were in NYHA class I at last follow up. Actuarial freedom from structural valve deterioration was 86% at 12 years. Freedom from endocarditis was 95% at 12 years. Freedom from a valve-related reoperation at 12 years follow up was 95%. Mean residual transprosthetic gradient at 12 years was 10.3 ± 4.8MmHg. Last-generation stentless pericardial valves offer excellent hemodynamics and adequate durability and freedom from structural deterioration at 12 years follow up. The implantation technique of a stentless valve is a little more demanding when compared to a stented valve, but it can be easily reproduced after minimal training. Incidence of endocarditis and thromboembolic events is low and comparable to stented pericardial valves. Young and active patients, and patients with large BSA where a patient-prosthesis mismatch may be anticipated are, in our opinion, ideal candidates to receive these kinds of valves.

High-speed videography of an exemplary porcine aortic valve after the valve-sparing aortic root replacement using the straight graft configuration.

High-speed videography of an exemplary porcine aortic valve after the valve-sparing aortic root replacement using the straight graft configuration.

Biomechanics and clinical outcomes of various conduit configurations in valve sparing aortic root replacement.

Several conduit configurations, such as straight graft (SG), Valsalva graft (VG), anticommissural plication (ACP), and the Stanford modification (SMOD) technique, have been described for the valve-sparing aortic root replacement (VSARR) procedure. Prior ex vivo studies have evaluated the impact of conduit configurations on root biomechanics, but the mock coronary artery circuits used could not replicate the physical properties of native coronary arteries. Moreover, the individual leaflet's biomechanics, including the fluttering phenomenon, were unclear. Porcine aortic roots with coronary arteries were explanted (n=5) and underwent VSARR using SG, VG, ACP, and SMOD for evaluation in an ex vivo left heart flow loop simulator. Additionally, 762 patients who underwent VSARR from 1993 through 2022 at our center were retrospectively reviewed. Analysis of variance was performed to evaluate differences between different conduit configurations, with post hoc Tukey's correction for pairwise testing. SG demonstrated lower rapid leaflet opening velocity compared with VG (P=0.001) and SMOD (P=0.045) in the left coronary cusp (LCC), lower rapid leaflet closing velocity compared with VG (P=0.04) in the right coronary cusp (RCC), and lower relative opening force compared with ACP (P=0.04) in the RCC. The flutter frequency was lower in baseline compared with VG (P=0.02) and in VG compared with ACP (P=0.03) in the LCC. Left coronary artery mean flow was higher in SG compared with SMOD (P=0.02) and ACP (P=0.05). Clinically, operations using SG compared with sinus-containing graft was associated with shorter aortic cross-clamp and cardiopulmonary bypass time (P<0.001, <0.001). SG demonstrated hemodynamics and biomechanics most closely recapitulating those from the native root with significantly shorter intraoperative times compared with repair using sinus-containing graft. Future in vivo validation studies as well as correlation with comprehensive, comparative clinical study outcomes may provide additional invaluable insights regarding strategies to further enhance repair durability.

Thoracic Aortic Arch Repair and Debranching in Thoracic Endovascular Aortic Repair Stent Migration

Thoracic endovascular aortic repair is a common reparative approach to aortic injury. Common long-term complications include endo-leak and stent migration. However, in some patients, an aortic arch repair with debranching may reduce the risk of further endo-leakage and migration. This poster presentation aimed to outline a novel approach to an open thoracic endovascular aortic repair (TEVAR) stent migration with an aortic arch repair with debranching utilising a 20-mm Gelweave straight graft anastomosed end-to-end.

Is a four-branched prosthesis advantageous over a straight prosthesis in Frozen elephant trunk surgery?

For years, the elephant trunk (ET) technique has been applied to extended aortic arch pathology facilitating staged downstream open- or endovascular completion. The recent use of a stentgraft as so-called frozen ET enables even single-stage repair, or its use as a scaffold in an acutely or chronically dissected aorta. Hybrid prosthesis have since been introduced, available as either a 4-branch graft or a straight graft for reimplantation of the arch vessels using the classic island technique. Both techniques are known to have technical advantages and disadvantages in specific surgical scenarios. In this paper we will discuss whether a 4-branch graft hybrid prosthesis is advantageous over a straight hybrid prosthesis. Our considerations in terms of mortality, cerebral embolic risk, myocardial ischemia time, cardiopulmonary bypass (CPB) time, hemostasis and exclusion of supra-aortic entries in the case of acute dissection will be shared. The 4-branch graft hybrid prosthesis conceptually facilitates reduced systemic-, cerebral-, and cardiac arrest time. Additionally, atherosclerotic ostial debris, intimal re-entries, and fragile aortic tissue in genetic disease can be excluded by using a branched graft instead of the island technique for reimplantation of the arch vessels. Despite many conceptual technical advantages of the 4-branch graft hybrid prosthesis, literature data do not show significantly better outcomes when compared to the straight graft, to support its routine use in all cases.

Comparison of Distal Arterial Hemodynamic Changes of the Upper Extremity Loop and Straight Arteriovenous Grafts

Hemodialysis access has been considered as a support for end-stage renal patients. We measured the hemodynamic changes of the distal part of the upper extremity immediately after providing the AVGs in each method mentioned above and then compared the results. This method is a novel one and hasn’t been used in any other studies before. We studied 32 patients referred to the vascular surgery department of Rasht Razi Hospital between 2019-2020 (using the Convenient Sampling method). This study is a case-control study. Out of 32 patients referred to the vascular surgery department of the hospital, 68.8% were male, and their mean age was 53.41±12.75 years, ranging from 28 to 78 years. Changes in distal arterial hemodynamics of the upper limb before and after clamping in dialysis venoarterial loop versus straight grafts are different in studied patients (P&lt;0.05). The mean hemodynamic changes before and after clamping in loop venoarterial grafts (19.5000) are less than straight grafts. In dialysis patients who do not have any superficial vein suitable for venous, arterial fistula, surgical placement of artificial grafts in the upper limb is appropriate. Based on the results of this study, the loop method seems to have lesser ischemic Complications and can be applied to dialysis patients.

Applicability of endovascular branched and fenestrated aortic arch repair devices to treat residual type A dissection after ascending replacement.

Endovascular repair of post-type A aortic dissection (PTAD) after open ascending replacement has recently been shown as safe and feasible, but with limited anatomic applicability because only one stent graft was evaluated. We assessed anatomic and clinical applicability of six commercially available branched/fenestrated stent grafts for endovascular repair of PTAD. On postoperative CT scans of 101 patients, we measured the aortic diameter at the sinutubular junction, supra-aortic vessels, and descending aorta, as well as the distances between these landmarks along the outer curvature of the arch and the diameters of the supra-aortic vessel. Anatomic applicability was evaluated according to the instructions for use, clinical applicability with regard to supra-aortic and iliac arteries. Assessed devices were the Cook aortic double branch, Terumo double branch, Najuta fenestrated, Endospan Nexus, Medtronic Mona LSA, and Gore TAG thoracic branch. Single devices were anatomically and clinically applicable between 19 of 101 (Mona LSA) and 83 of 101 (Najuta) cases. Reasons for rejection varied considerably across devices. With all devices available, anatomic applicability was 97 of 101 and clinical applicability 95 of 101. Combinations of a fenestrated and a branched device showed the most favorable clinical applicability for a pair of two devices, ranging from 86 of 101 to 94 of101. Anatomic and clinical applicability of endovascular devices for the repair of PTAD is high for fenestrated and branched devices, and very high for the combination of fenestrated and branched devices. Manufacturers should amend specific device requirements for PTAD. Surgeons should emphasize the need for a sufficiently long and straight graft as a potential landing zone.

Abstract 11145: Biomechanical Engineering Analysis of Leaflet Kinematics and Native Coronary Flow After Valve-Sparing Aortic Root Replacement Using Four Graft Configurations

Introduction: Different ex vivo root biomechanics after valve-sparing aortic root replacement (VSARR) using several graft configurations have been described. The impact of graft choice on each cusp’s kinematics and native coronary flow remains unclear. The objective was to analyze valve kinematics and coronary flow after VSARR using 4 graft configurations in a 3D-printed heart simulator ( Fig A ).[YZ1] Methods: Porcine aortic roots with coronary arteries were explanted (n = 5). Native roots served as controls ( Fig B ). Each sample underwent VSARR using straight graft (SG), Valsalva graft (VG), anti-commissural plication (ACP), and Stanford modification (SMOD) in a random order ( Fig C-G ). Hemodynamics and videometric data were analyzed ( Fig H, I ). Results: SG showed the lowest regurgitant fraction (2.8 ± 1.5 %) compared to control (6.3 ± 3.9 %, p = .0002), VG (12.2 ± 3.6 %, p = .002), ACP (12.9 ± 1.3 %, p = .001), and SMOD (12.2 ± 3.0 %, p = .001, Fig J, K ). The left coronary artery flow was higher in SG (0.68 ± 0.16 L/min) compared to VG (0.55 ± 0.22 L/min, p = 0.05) and SMOD (0.51 ± 0.23 L/min, p = 0.05, Fig L ). The right coronary artery flow was higher in SG (0.20 ± 0.10 L/min) compared to VG (0.07 ± 0.04 L/min, p = 0.04) and SMOD (0.08 ± 0.05 L/min, p = 0.04, Fig M ). SG (26.5 ± 17.6 cm/s) compared to VG (48.3 ± 19.0 cm/s, p = .001) and SMOD (39.5 ± 10.1 cm/s, p = .05) showed lower rapid opening velocity in the left coronary cusp (LCC). SG (8.1 ± 6.2 cm/s) compared to VG (15.0 ± 10.6 cm/s, p = .04) showed lower rapid closing velocity in the right coronary cusp. The VG (17.7 ± 9.7 Hz) had higher flutter frequency in the LCC compared to control (11.9 ± 4.1 Hz, p = .02). The SG (11.9 ± 4.5 dB/Hz) compared to ACP (16.4 ± 4.7 dB/Hz, p = .01) showed lower flutter power in the LCC. Conclusions: Compared to other configurations, SG had the most optimal hemodynamics, native coronary flow, and leaflet kinematics. Further in vivo validation studies should be performed to evaluate flow dynamics in the root and assess for clinical applicability.

NEO E-vita\u2014NEO era!

In this review article, the history of the first commercially available thoracic aortic hybrid graft, the E-vita Open, later modified to the blood-impermeable E-vita Open Plus, is reported from its beginning in 2005 until its newest variation, the E-vita Open NEO, European conformity (CE) marked in 2020. Besides the background of its design and clinical experience in Essen, concomitant evolutionary steps in surgery as well as in strategic approaches like the hybrid operating room concept are displayed, finally leading to a well-rounded surgical package with a device that can be applied in all elective as well as emergency situations with complex arch involving aortic pathologies. With the E-vita Open NEO, now, surgery has been facilitated to convenient anastomosing in any of the arch zones, with the opportunity to use the island technique with a straight graft variation as well as individual head vessel anastomosing with either a trifurcated graft for zone 0 or the branched graft for zone 2 or 3 implantation. With its proven long-term stability, the surgical armamentarium to cope with complex multisegmental thoracic aortic pathologies has been significantly improved.

Similar Midterm Clinical Outcomes and Aortic Remodeling in Bifurcated and Straight Aortic Stent Grafts Used to Treat Isolated Abdominal Aortic Dissection

Purpose: The optimal treatment for isolated abdominal aortic dissection (IAAD) is currently unknown. We compared the effects of straight and bifurcated aortic stent grafts on postoperative aortic remodeling in patients with IAAD. Materials and Methods: From February 2012 to December 2019, 57 patients with IAAD were treated using endovascular methods, including either a bifurcated or a straight aortic stent graft. The clinical features, risk factors, computed tomography angiograms, midterm follow-up results, and aortic remodeling of these patients were reviewed and analyzed. Results: In total, 44 (77%) patients were treated with a bifurcated graft and 13 (23%) patients were treated with a straight graft. Patients treated with straight grafts had fewer common iliac arteries involved (38% vs 73%, p=0.023), the dissection length was shorter (76.3 ± 40.0 vs 116.2 ± 56.7 mm, p=0.011), and the preoperative aortic diameter (26.0 ± 5.6 vs 35.2 ± 12.1 mm) and the false lumen diameter (13.1 ± 5.2 vs 21.2 ± 11.3 mm) were smaller. During the procedure, there were 3 (5.3%) type I endoleaks, 1 (1.8%) surgical conversion and 1 (1.8%) partial renal artery coverage without perioperative mortality. Patients with straight grafts had shorter operative time (96.5 ± 24.4 vs 144.2 ± 49.0 minutes, p<0.0001). The median follow-up duration was 37.6 ± 21.0 (range = 3–89) months with 1 (1.8%) aortic-related death. Type A aortic dissection occurred in 1 (1.8%) patient. New descending aortic dissection occurred in 3 (5.3%) patients, and 1 patient advanced to type A aortic dissection 3 months later. Two (3.5%) patients had limb occlusion. There was no significant difference in aortic remodeling, survival, and freedom from all adverse events between the 2 treatment strategies. Conclusions: Endovascular treatment provides a safe, minimally invasive treatment for IAAD in midterm follow-up. Compression of the true lumen at the aortic bifurcation is the main concern after treatment with a bifurcated graft. Straight grafts are an excellent alternative for some patients, with the benefit of reduced procedural time, effective aortic remodeling, and excellent clinical prognosis. More experience is needed to offer clear recommendations for making treatment decisions as well as determine long-term effectiveness and durability.

Total autogenous revascularization of an innominate artery occlusive disease

Total autogenous revascularization of an innominate artery occlusive disease

Our clinical experiences of vascular injuries due to lumbar disc surgeries.

We aimed to evaluate emergency vascular complications of the lumbar disc reconstructive surgery in this study. Between March 2006 and February 2020, nine patients (six males and three females; mean age: 53.4 ± 9.6 years; range: 38-64 years) who underwent emergent vascular intervention during lumbar spinal disc reconstructive surgery in our clinic were included in this retrospective study. The left common iliac artery injury, the left common iliac artery and left common iliac vein injuries, bilateral common iliac artery and abdominal aortic injuries, and vena cava inferior injury with left common iliac vein and right common iliac vein injuries were detected in two, three, two, and two patients, respectively. In addition, 16 mm Dacron tube graft interposition and graft patch plasty were performed in one and two patients who had an abdominal aortic injury, respectively. Also, 8 mm polytetrafluoroethylene straight graft interposition was performed in two patients with left common iliac artery injury, and lateral wall repair was performed in other patients. Graft patch plasty and 8 mm polytetrafluoroethylene graft interposition were performed in one patient with vena cava inferior injury and left common iliac vein injury, respectively. Also, lateral wall repair was performed in other patients with venous injuries. Deep venous thrombosis had developed in three patients, and one patient of these had a pulmonary embolism. The incidence of vascular injury after the lumbar disc surgery is relatively low; however, the emergency vascular operation should be performed as soon as possible.

Enodvascular treatment of isolated abdominal aortic dissection

Objective: To examine the outcome of endovascular treatment in patients of isolated abdominal aortic dissection. Methods: From February 2012 to June 2020, 61 patients (44 males, 17 females) with an age of (60.2±11.4) years (range: 43 to 87 years) of isolated abdominal aortic dissection who underwent the endovascular treatment, including bifurcated and straight aortic stent graft, in the Department of Vascular Surgery, the Second Xiangya Hospital, Central South University were enrolled. There were 47 patients treated with bifurcated aortic stent grafts and 14 patients with straight aortic stent grafts. Patient demographic, preoperative, intraoperative, perioperative data were collected. Clinical follow-up data, including mortality, relative complications and aortic remodeling, were obtained. Kaplan-Meier method and Log-rank test was used to calculate and compare the rates of survival and freedom from all adverse events. Results: The operative time was (142.4±47.9) minutes (range:70 to 310 minutes) and (95.7±23.7) minutes (range: 70 to 150 minutes) in bifurcated stent group and straight stent group, respectively. The perioperative mortality was 0. One patient had partial occlusion of the left renal artery, and 3 patients had type Ⅰa endoleak post-operation. The follow-up period was (37.1±22.1) months (range: 3 to 91 months). Three patents suffered from type B aortic dissection; one of them progressed into type A aortic dissection and died, another one was treated with secondary endovascular operation, and the remaining one was treated conservatively. One patient had type A aortic dissection and was treated conservatively for 57 months without any discomfort. Stent grafts in iliac artery occlusion happened in 2 patients treated with a bifurcated graft, one of them was treated with a secondary operation because of severe symptom. Aortic remodeling was well with the treatment of bifurcated and straight grafts. There was no difference in the cumulative survival (P=0.584) and freedom from all adverse events (P=0.309) between the two different endovascular treatment strategies. Conclusion: Endovascular aortic repair is an effective and safe treatment strategy for isolated abdominal aortic dissection with reliable mid-term result and excellent aortic remodeling.

Patient with Unicuspid Aortic Valve and Ascending Aorta Aneurysm Treated with Ozaki Procedure and Ascending Aorta Replacement

Although aortic valve replacement remains the gold standard treatment for aortic valve diseases like stenosis (AS) or insufficiency, new surgical methods have been developed with a focus in the reconstruction of the aortic valve rather than replacing it. The Ozaki procedure involves a tailored replacement of each individual valvular leaflet with glutaraldehyde-treated autologous pericardium and aims to reproduce the normal anatomy of the aortic valve. Cases of patients with unicuspid aortic valve treated with the Ozaki procedure are uncommon in the litrature and become even more rare when it comes to concomitant diseases like AS and ascending aorta aneurysm.We present the case of a 21-year-old, fit and asymptomatic male, with unicuspid aortic valve with severe stenosis and ascending aorta dilatation, surgically treated with tricuspidization of the aortic valve with glutaraldehyde-treated autologous pericardium and replacement of the ascending aorta with a straight synthetic graft. Postoperative studies showed a fully functional, neo-tailored tricuspid aortic valve with trivial regurgitation. The patient had an uncomplicated recovery, stayed in the intensive care unit for 2 days and was discharged on the 7th postoperative day.

Haemodynamic optimisation of a dialysis graft design using a global optimisation approach.

Disturbed flow and the resulting non‐physiological wall shear stress (WSS) at the graft‐vein anastomosis play an important role in arteriovenous graft (AVG) patency loss. Modifying graft geometry with helical features is a popular approach to minimise the occurrence of detrimental haemodynamics and to potentially increase graft longevity. Haemodynamic optimisation of AVGs typically requires many computationally expensive computational fluid dynamics (CFD) simulations to evaluate haemodynamic performance of different graft designs. In this study, we aimed to develop a haemodynamically optimised AVG by using an efficient meta‐modelling approach. A training dataset containing CFD evaluations of 103 graft designs with helical features was used to develop computationally low‐cost meta‐models for haemodynamic metrics related to graft dysfunction. During optimisation, the meta‐models replaced CFD simulations that were otherwise needed to evaluate the haemodynamic performance of possible graft designs. After optimisation, haemodynamic performance of the optimised graft design was verified using a CFD simulation. The obtained optimised graft design contained both a helical graft centreline and helical ridge. Using the optimised design, the magnitude of flow disturbances and the size of the anastomotic areas exposed to non‐physiological WSS was successfully reduced compared to a regular straight graft. Our meta‐modelling approach allowed to reduce the total number of CFD model evaluations required for our design optimisation by approximately a factor 2000. The applied efficient meta‐modelling technique was successful in identifying an optimal, helical graft design at relatively low computational costs. Future studies should evaluate the in vivo benefits of the developed graft design.

Comparison of Patency in 5- and 6-mm Hemodialysis Grafts

Highlights Abstract Objectives: Arteriovenous grafts (AVGs) are often the mode of vascular access of choice because poor blood vessels in patients hinder the creation of arteriovenous fistulas (AVFs). The present study aimed to compare the characteristics and patency rates between 5-mm and 6-mm straight grafts. Methods: We analyzed 119 cases involving AVG operations performed at a single center. The cases were divided into 2 groups based on the size of the straight graft, namely 5-mm (62.2%) and 6-mm (37.8%) grafts. The differences in the baseline characteristics, perioperative data, and patency rates between the groups were subsequently analyzed. Results: Patients who received 5-mm grafts were predominantly female (P = 0.042) and had a higher body mass index (BMI; P = 0.012) than those who received 6-mm grafts. The 5-mm graft group showed increased primary patency (P = 0.035). However, significant intergroup differences were not observed with respect to the secondary patency rates (P = 0.087). A multivariable analysis confirmed that higher BMI (P = 0.022), cause of diabetes mellitus nephropathy (P = 0.015), frequency of the procedure (≥5 times; P = 0.002), and procedure time (P = 0.028) were significant independent variables that affected the primary patency rates. Conclusions: Five-mm grafts were associated with higher BMI, female predominance, and increased primary patency compared with the 6-mm grafts. Therefore, 5-mm grafts should be considered for patients with poor blood vessels.

Outcome of Percutaneous Intervention in Dysfunctional Loop versus Straight Arteriovenous Grafts in Hemodialysis Patients.

Objective:To compare the patency control of dysfunctioning forearm arteriovenous graft (AVG) using percutaneous transluminal angioplasty (PTA) in patients with loop versus straight grafts.Materials and Methods:Between January 2012 and March 2017, hemodialysis patients with forearm AVG were treated with PTA at two hospitals. We reviewed technical and clinical success rates of each procedure. Procedure time and patency of the graft were compared for all patients as well as for subgroups of stenosis only and thrombosis using paired-sample t-test and Kaplan-Meier analysis.Results:Sixty-six patients (mean age, 62.11 ± 11.85 years) underwent PTA. Thirty-eight patients (58%) had loop grafts and 28 (42%) had straight grafts. Among 66 patients, 54 (82%) had thrombosis. Technical success rate was 95.5% (only stenosis: 100%; thrombosis: 94%) and the mean procedure time was 48.00 ± 16.75 minutes in all patients. Although there was a tendency towards shorter procedure time in patients with loop grafts (45.24 ± 20.24 minutes) than those with straight grafts (51.85 ± 22.76 minutes), the difference was not statistically significant (p = 0.217), with or without thrombi. There was no statistical significance in primary and assisted primary patency (log rank 0.78, p = 0.38 in primary patency; log rank 0.88, p = 0.35 in assisted primary patency).Conclusion:Our study suggests there is no different patency outcome between straight and loop arteriovenous grafts after PTA.

Branched Endograft Partial Deployment to Save Space for Vessel Cannulation When Treating Aneurysms with Narrow Aortic Lumen

To describe a novel technique developed for the treatment of patients with thoracoabdominal aortic aneurysms having narrow aortic lumens using branched endografts. When treating patients with a narrow aortic inner diameter with branched endografts, we propose a partial graft deployment leaving the distal portion of the device inside the delivery system with the aim of spare space and facilitate target vessel cannulation. Partial endograft deployment could be considered in the case of expected difficulty associated with encumbrance deriving from the distal straight graft portion. This technique could be useful to avoid target vessel loss and therein save procedural and fluoroscopy time.