Polytetrafluoroethylene Tube Graft Research Articles

Handmade Bicuspid Valved Polytetrafluoroethylene Conduit for Right Ventricular Outflow Tract Reconstruction.

Background: Excellent outcomes of right ventricle to pulmonary artery conduits with polytetrafluoroethylene (PTFE) valves have been reported. The purpose of this study was to analyze the short-term results of our handmade PTFE bicuspid valved conduit (VC) for right ventricular outflow tract reconstruction. Methods: Between September 2019 and May 2023, bicuspid PTFE-VC was implanted in 17 patients at a median age of 2.5 years (range, 3 months to 13.6 years). The PTFE-VC was fashioned from a commercially available PTFE tube graft (14 mm in three patients, 16 mm in three patients, 18 mm in one patient, 20 mm in three patients, and 22 mm in seven patients) and 0.1 mm thick PTFE membrane for the leaflet material. Valve function was assessed by echocardiogram after the implantation. The conduit reoperation and the conduit dysfunction were analyzed. There were no early deaths, but there was one late death. Results: There were no postoperative in-hospital deaths. Follow-up echocardiograms were available for 14 of 17 patients. The median follow-up was 21 months (range, 7-49 months). Conduit stenosis was none or trivial in 11 patients while it was mild in two and moderate in one patient and severe in 0 patients. Conduit insufficiency was mild or trivial in all 14 patients. By the end of the study period, freedom from reoperation/reintervention was 100%. There were no episodes of aneurysmal dilatation of the conduit or endocarditis. Conclusions: Handmade bicuspid PTFE VC shows good short-term outcome, with no significant valve dysfunction and no reintervention. A longer follow-up is necessary to evaluate the long-term advantages of using the handmade bicuspid PTFE VC.

Technical modification and safe explantation of the Melody valve in the mitral position in small children.

Technical modification and safe explantation of the Melody valve in the mitral position in small children.

A Unique Case of an Expanded Polytetrafluoroethylene Graft Rupture 14 Years after Abdominal Aortic Aneurysm Open Repair Managed with Placement of a Thoracic Endograft.

We report a unique case of expanded polytetrafluoroethylene (ePTFE) tube graft rupture that occurred 14 years after abdominal aortic aneurysm (AAA) repair. Endovascular repair with a thoracic endograft was performed. Postoperatively, an increase in the size of the existing hematoma with active extravasation occurred and was managed with iliolumbar artery embolization. Τo the best of our knowledge, rupture of ePTFE graft used for AAA repair has not been reported in the literature.

Jugular Vein Phlebectasia (IJP): Surgically Manageable But Ignored Entity.

IJP is a rare, congenital, benign, isolated, sporadically occurring fusiform or saccular dilatation of Internal Jugular Vein (IJV) of unknown aetiology usually presenting as a unilateral neck mass. It is mostly seen in children and young adults. We report a 4year old male presented to Expert ENT & Diagnostic Centre presenting with history of painless right neck swelling in the right carotid triangle first observed on crying with no history of trauma, facial congestion, chronic cough, difficulty in swallowing or breathing, non febrile, venous humps, heaviness or cessation of normal voice. Diagnosis of right IJP was made. Exploration and wrapping the dilated segment in polytetrafluoroethylene tube graft was done. Because of its rarity, this entity is frequently ignored or misdiagnosed. This case report intends to stress the importance of keeping IJP as differential diagnosis while dealing with such a swelling to avoid invasive investigations and inappropriate treatment.

A Novel Arterial Cannulation Technique for Selective Regional Cerebral Perfusion

A selective regional cerebral perfusion has been widely adopted for brain protection in neonatal or infant aortic arch surgeries. The anastomosis of the small polytetrafluoroethylene tube graft to the innominate artery hasbeen used for the selective regional cerebral perfusion inmany institutions. We have developed a specially designed cannula tip that allows bidirectional bloodflowand provides secure positioning of the polytetrafluoroethylene tube graft at the innominate artery. Innominate artery cannulation using this device reduces arterial clamping time and permits us to perform the arterial cannulation in a much easier and secure manner.

An Easy Modification of Tube Graft Interposition During Fenestration in Borderline Fontan Circulation

One of the options for the management of borderline/failing extracardiac Fontan circulation is surgical creation of an atrial fenestration to decompress the systemic venous compartment and improve cardiac output. Depending on the body surface area of the patient, a 5- to 10-mm polytetrafluoroethylene (PTFE) tube graft can be used. When fenestration is required in a patient with failing Fontan circulation, particularly in redo cases, application of a side-biting clamp may be challenging because of adhesions and a thickened atrial wall. In this article, we present our off-pump technique of atrial-side anastomosis of PTFE graft interposition between an extracardiac Fontan conduit and the atrium without using a side-biting clamp.

Computational fluid dynamics characterization of blood flow in central aorta to pulmonary artery connections: importance of shunt angulation as a determinant of shear stress-induced thrombosis.

The central aortic shunt, consisting of a Gore-Tex (polytetrafluoroethylene) tube (graft) connecting the ascending aorta to the pulmonary artery, is a palliative operation for neonates with cyanotic congenital heart disease. These tubes often have an extended length, and therefore must be angulated to complete the connection to the posterior pulmonary arteries. Thrombosis of the graft is not uncommon and can be life-threatening. We have shown that a viscous fluid (such as blood) traversing a curve or bend in a small-caliber vessel or conduit can give rise to marked increases in wall shear stress, which is the major mechanical factor responsible for vascular thrombosis. Thus, the objective of this study was to use computational fluid dynamics to investigate whether wall shear stress (and shear rate) generated in angulated central aorta-to-pulmonary artery connections, invivo, can be of magnitude and distribution to initiate platelet activation/aggregation, ultimately leading to thrombus formation. Anatomical features required to construct the computer-simulated blood flow pathways were verified from angiograms of central aortic shunts in patients. For the modeled central aortic shunts, we found wall shear stresses of (80-200N/m(2)), with shear rates of (16,000-40,000/s), at sites of even modest curvature, to be high enough to cause platelet-mediated shunt thrombosis. The corresponding energy losses for the fluid transitions through the aorta-to-pulmonary connections constituted (70%) of the incoming flow's mechanical energy. The associated velocity fields within these shunts exhibited vortices, eddies, and flow stagnation/recirculation, which are thrombogenic in nature and conducive to energy dissipation. Angulation-induced, shear stress-mediated shunt thrombosis is insensitive to aspirin therapy alone. Thus, for patients with central aortic shunts of longer length and with angulation, aspirin alone will provide insufficient protection against clotting. These patients are at risk for shunt thrombosis and significant morbidity and mortality, unless their anticoagulation regimen includes additional antiplatelet medications.

A central shunt to rehabilitate diminutive pulmonary arteries in patients with pulmonary atresia with ventricular septal defect

We evaluated our clinical experiences on rehabilitation of native pulmonary arteries (PAs) with a central shunt using an expanded polytetrafluoroethylene (ePTFE) tube graft in management of pulmonary atresia with ventricular septal defect (VSD) and major aortopulmonary collateral arteries (MAPCAs) with diminutive PAs. From March 1993 to June 2013, a total of 28 consecutive patients underwent surgery for pulmonary atresia with VSD and MAPCAs. We identified 15 patients who underwent a central shunt procedure using an ePTFE tube graft. Median age and weight at the initial operation were 1.91 months and 5.22 kg, respectively. Ligation of MAPCAs was performed in 3 patients concomitantly. The techniques used were a U-shaped central shunt in 13 patients, and a side-to-side aorto-ePTFE tube graft anastomosis in 2 patients. There was no surgical mortality, and no shunt occlusion. The mean follow-up duration was 70.7 ± 67.1 months. Complete repair was achieved in 13 patients (13 of 14 of the follow-up patients; 92.9%), and the remaining patient is waiting for complete repair. The median age at complete repair was 19.4 months. The mean PA index before the initial central shunt procedure was 22.7 ± 13.2 mm(2)/m(2), which increased to 149.4 ± 86.6 mm(2)/m(2) at the final recordings before shunt division, and 185.9 ± 84.0 mm(2)/m(2) before complete repair. There were 2 late mortality cases. The overall survival rates were 92.9%, 82.5%, and 82.5%, at 1, 5, and 10 years, respectively. A central shunt, using an ePTFE tube graft, is an effective initial palliative procedure for rehabilitation of the diminutive PAs in patients with pulmonary atresia with VSD and MAPCAs.

Left Main Coronary Artery Compression Long Term After Repair of Conotruncal Lesions: The Bow String Conduit

We report 4 cases of left main coronary artery (LMCA) compression after remote repair of conotruncal lesions and their successful surgical management.

Phlebectasia of Internal Jugular Vein

Internal jugular phlebectasia (IJP) is a rare disease in which there is a fusiform dilatation of internal jugular vein, usually presenting as a neck mass in children. Accurate diagnosis from careful history, physical examination, and radiological study can be made. We report a 12-year-old boy with history of swelling appearing on the right side of the neck only on straining, coughing, or during a Valsalva maneuver. Diagnosis of right IJP was made. Exploration and wrapping the dilated segment in an 8-mm-diameter polytetrafluoroethylene tube graft was done. Because of its rarity, this entity is frequently ignored or misdiagnosed. This case report intends to stress the importance of keeping IJP as differential diagnosis while dealing with such a swelling to avoid invasive investigations and inappropriate treatment.

Long-term dilatation of polyester and expanded polytetrafluoroethylene tube grafts after open repair of infrarenal abdominal aortic aneurysms

Since 1995, expanded polytetrafluoroethylene (ePTFE) grafts have been implemented in open surgical repair (OSR) of abdominal aortic aneurysms (AAA) and are supposed to show less dilatation than polyester grafts. This study examined differences in graft dilatation and clinical outcome. This single-center long-term, prospective randomized study monitored 99 consecutive patients after OSR of AAA. Implanted were 90 tube ePTFE Gore-Tex Stretch grafts, 56 tube Dacron grafts (Uni-Graft KDV, polyester, B. Braun, knitted), and 51 tube Dacron grafts (Gelseal Plus, polyester, Vascutek, triaxial knitted). Follow-up with ultrasound examination was performed at discharge, at 12 months, and at 6 years. Patients were a mean age of 67 years. Thirty-day mortality was 2.5% (n = 5 of 199), without significant differences among the groups. The Kaplan-Meier analysis showed 5-year survivals of 0.82 (ePTFE/Gore), 0.81 (polyester/Braun), and 0.83 (polyester/Vascutek). Mean ± standard deviation dilatation of the midgraft segment was 1% ± 5% (ePTFE/Gore), 10% ± 9% (polyester/Braun), and 7% ± 8% (polyester/Vascutek) (P ≤ .001) at discharge; 8% ± 11% (ePTFE/Gore), 24% ± 7% (polyester/Braun), and 20% ± 13% (polyester/Vascutek; P ≤ .001) after 12 months; and 19% ± 21% (ePTFE/Gore), 33% ± 22% (polyester/Braun), and 23% ± 19% (polyester/Vascutek; (P ≤ .001) after 6 years. No graft failure or rupture occurred. Graft patency was 100%. After a mean implantation of 6 years, the ePTFE/Gore, polyester/Braun, and polyester/Vascutek tube grafts presented with significant differences. The ePTFE grafts showed a stronger resistance against dilatation than the two types of polyester grafts. Owing to similar perioperative and postoperative courses, no advantage could be identified in any group concerning the overall outcome. Vascular implants for OSR of AAA made of ePTFE and polyester are safe, even after a long implantation time. Therefore, the choice of the suitable graft does not depend on its postimplantation dilative characteristics. The outcome is not likely to be connected with dilatation of the implanted graft, because a causal connection between graft dilatation and death cannot be made. The study does not offer a basis for the preference of one of the three graft types. Nevertheless, continuous ultrasound examinations should be performed after implantation of an aortic tube graft to identify possible problems arising from changes in the graft and the residual vascular branches over time.

Partial Anomalous Pulmonary Venous Connection to the Superior Vena Cava

We describe the surgical technique of reimplantation of the right superior pulmonary vein into the left atrium in 2 patients with partial anomalous pulmonary venous connection to the superior vena cava without atrial septal defect. A right axillary minithoracotomy is done through the fourth intercostal space. The pulmonary vein is detached from its origin in the superior vena cava. This is sutured with 6-0 reabsorbable polydioxanone suture (Ethicon, Somerville, NJ). A lateral clamp is applied to the left atrium, and the pulmonary vein is reimplanted. The patient is extubated in the operating room. Neither cardiopulmonary bypass nor blood transfusion was required. It is simple, safe, and reproducible.

Developing and Optimizing a Chronic Cyanotic Swine Model

Pulmonary artery (PA)-left atrial (LA) shunt models in piglets have been described, but technical details critical to limit morbidity/mortality and promote study of chronic cyanosis are lacking. Accordingly, we describe our experience with an optimized technique. In 25 6- to 8-wk-old Yorkshire piglets, a beveled, 8 mm, polytetrafluoroethylene tube graft was anastomosed to the PA and LA. Systemic pressure was maintained at >60 mmHg. Saturation targets were met by adjusting a Teflon band on the graft and distal PA. The target oxygen saturation (SO(2)) was 85% on a 50% fraction of inspired oxygen (FiO(2)). If the SO(2) was <75% on a 50% FiO(2), the graft was constricted to achieve a SO(2) ≥ 90% on a 100% FiO(2) and 75%-80% on a 21% FiO(2). Complications affecting mortality were neutralized with a stepwise strategy to minimize risk. Thrombosis, blood loss, and arrhythmia were determinants of survival. Protocol optimization over time increased survival while assuring chronic cyanosis. Survival approached 90%, with a SO(2) of 80% to 90%, 3 to 5 wk postoperatively. Complications included bleeding, excessive hypoxemia, uncontrolled shunt flow, arrhythmias, and thrombosis. Refinement of surgical technique, shunt adjustment via graft banding, and thrombotic and arrhythmia prophylaxis are the keys to success with this model.

Repair of a pararenal abdominal aortic aneurysm with bilateral renal artery stenosis using a rapid infusion pump for renal perfusion: Report Of a case

A 73-year-old man with a history of hypertension and drug-induced hepatitis underwent surgical treatment of an enlarging pararenal abdominal aortic aneurysm (PRAAA) with bilateral renal artery stenosis, found on enhanced computed tomography (CT). His preoperative renal function was normal. We divided the right renal artery and used a 6-mm expanded polytetrafluoroethylene (ePTFE) tube graft for the anastomosis. Renal artery perfusion was achieved by a rapid infusion pump set at 200 ml/min. The left renal artery was reconstructed and perfused in the same way. The abdominal aorta was cross-clamped just distal to the superior mesenteric artery and a Y-graft was anastomosed. The ePTFE grafts were connected to the Y-graft and bilateral renal artery circulation was re-established. The renal ischemic time was 1 h 25 min and the urine output during reconstruction was 80 ml. Postoperatively, his serum blood urea nitrogen and serum creatinine levels increased slightly, but normalized within 3 days. This case report shows that this method of renal artery perfusion could prove useful for complex renal artery reconstructions.

Experience with aortic grafting during excision of large abdominal neuroblastomas in children

Total or near total resection of high-risk, stage 4 abdominal neuroblastoma has been correlated with improved local control and overall survival but may be complicated by vascular injury. We describe our experience in the management of significant aortic injuries during this procedure. With the institutional review board waiver, medical records of children who had major abdominal aortic reconstruction during neuroblastoma resection from 1996 to 2006 were retrospectively reviewed. There were 5 children with aortic grafting: 3 girls and 2 boys. Mean age at surgery was 7.2 years (range, 16 months to 17 years). Two children were operated on for recurrent retroperitoneal disease. Tumor encasement of the aorta was seen in all children. In 3 children, the injury occurred during dissection of paraaortic and interaortocaval lymph nodes below the level of the renal arteries. In the remaining 2 children, injury occurred early during mobilization of the tumor. Three polytetrafluoroethylene tube grafts and 1 on-lay patch graft were used to repair the 4 distal aortic injuries. One 4-year-old female with aortic and renal arterial injuries was managed with an aortic Dacron tube graft and a polytetrafluoroethylene tube graft for the renal artery. The mean period of follow-up is 28 months after aortic graft (range, 3 months to 10 years). Total colonic ischaemia, transient acute tubular necrosis, and duodenal perforation were seen in one child, who needed subtotal colectomy and ileostomy. Another child with an omental patch over the graft had a transient duodenal obstruction, which was managed conservatively. There were no other complications, and 4 of the 5 children are disease-free to date. One child at 10 years after his distal aortic tube graft remained asymptomatic with normal distal blood flow on magnetic resonance angiogram and with normal growth. The neuroblastoma surgeon should be prepared to perform aortic and vascular reconstruction. Aortic encasement, preoperative radiation therapy, and reoperative surgery were observed in these patients and may be risk factors.

Iliac Conduit for Renal and Visceral Artery Access During Endovascular Repair of a Pararenal Aneurysm with a Fenestrated Stent-Graft

To report a technique for fenestrated stent-graft repair involving a conduit implanted at the origin of a patent aneurysmal common iliac artery (CIA) in a patient with a pararenal aortic aneurysm and iliac artery occlusion. A 60-year-old man with multiple comorbidities presented with an 8-cm abdominal aortic aneurysm (AAA) with no infrarenal neck according to computed tomography (CT). Both CIAs were aneurysmal; the left was occluded, as were the left internal and external iliac arteries and the inferior mesenteric artery. Two patent accessory renal arteries were depicted. Because an infrarenal neck was absent, treatment with a fenestrated endograft was performed under general anesthesia. The right CIA was approached via an oblique retroperitoneal incision. A 10-mm polytetrafluoroethylene tube graft was implanted on the origin of the right CIA aneurysm in an end-to-side fashion to facilitate delivery of a Zenith endograft constructed with 2 small fenestrations for the renal arteries, 1 large strut-free fenestration for the superior mesenteric artery, and a scallop for the celiac trunk. The proximal fenestrated body of the Zenith device was introduced via the right iliac artery by direct puncture of the common femoral artery. The conduit was used to cannulate the 3 fenestrations for subsequent deployment and for delivery of the distal Zenith aortomonoiliac device. The procedure was completed successfully, but 12 hours after surgery, the patient developed a significant right retroperitoneal hematoma, which was treated surgically. CT confirmed patency of all visceral arteries and no endoleak. One month after the initial procedure, he had recovered totally and was discharged. Iliac conduits could widen the feasibility of fenestrated endografting in patients unfit for open surgery with pararenal aneurysms and challenging iliac anatomy. However, this adjunctive procedure has its own morbidity.

Fate of Equine Pericardial Roll Conduit for Rastelli Operation during Long-term Follow-up

Right ventricular outflow tract obstruction is a frequent condition after Rastelli operation. Although several modifications have been reported elsewhere, ideal conduit has not been developed yet during long-term follow-up. We reviewed our experiences over 15-year long-term follow-up with patients who underwent Rastelli operation using house-made equine pericardial roll graft. Since June 1981, 16 patients underwent Rastelli operation with the pericardial roll graft. Median follow-up time was 15.6 years (7.3-26.8 years). Twelve out of 16 patients using pericardial roll graft with (n = 6) or without (n = 6) cusps underwent 13 reoperations during the follow-up period. Median time from first Rastelli to re-do operation was 8.4 years with median time to reoperation of 8 years. Major indication for reoperation was conduit obstruction (n = 10), but not conduit regurgitation. Conduit problem includes kinking and compression of the graft. Reoperation procedures include 7 Danielson procedures, 2 patch augmentations, 1 homograft replacement, 1 pericardial roll graft, 1 expanded polytetrafluoroethylene tube graft replacement, and 1 patch closure for pulmonary artery aneurysm. Balloon angioplasty was not effective for pericardial roll conduit stenosis. We conclude that house-made equine pericardial roll graft was durable for certain time period, but conduit change may be inevitable. Because of excellent handling and wide application, further modification may be warranted.

Léiomyosarcome du segment moyen de la veine cave inférieure : problèmes tactiques soulevés par la revascularisation cave et rénale

Introduction Leiomyosarcoma of the inferior vena cava is mesenchymal tumor accounting for 95% of primary tumors of the vena cava. Characteristic features include late invasion of adjacent structures and metastases, and delayed diagnosis. Observation We report a case of inferior vena cava (IVC) leiomyosarcoma (LMS) found in a 53 year-old man who complained of abdominal pain. Morphologic exams found a very large polycyclic mass in the inferior vena cava involving the middle segment of the vena cava extending from the renal veins to the hepatic veins. An «en bloc» resection of the tumor was achieved. Caval outflow was restored using a ring-reinforced PTFE tube graft, the left renal vein was ligated and not re-implanted, the right renal vein was implanted in a lumbar sub-renal vein using a short prosthesis. Pathological examination documented a grade II leiomyosarcoma of the inferior vena cava and the patient was given adjuvant chemotherapy (anthracycline). One year later, there was no local or regional relapse. Comment We emphasize the importance of restoring caval outflow which provides effective results when used with a ring-reinforced polytetrafluoroethylene (PTFE) prosthesis. Furthermore, the importance of restoring right renal outflow is highlighted because ligature of the renal vein can lead to renal ischemia and nephrectomy which should only be performed in specific cases. The tactical problems of renal and caval revascularisation, including the place of prosthetic replacement, are discussed. (J Mal Vasc 2006; 31: 79-84).

Superficial femoral artery transposition repair for isolated superior mesenteric artery dissection

Isolated dissection of the superior mesenteric artery is an uncommon event, but many new cases have been reported recently, reflecting the progress of imaging and suggesting that this pathology is not as rare as previously thought. Here we report a case of superior mesenteric artery dissection where we performed, after failure of conservative medical management, an original surgical technique for mesenteric revascularization using a superficial femoral artery transposition. To the best of our knowledge, this is the first report of the use of this technique for complex mesenteric revascularization.

Endovascular treatment of thoracic aortic aneurysms: Results of the phase II multicenter trial of the GORE TAG thoracic endoprosthesis

A decade after the first report of descending thoracic aortic aneurysm (DTA) repair with endografts, a commercial device is yet to be approved in the United States. The GORE TAG endoprosthesis, an investigational nitinol-supported expanded polytetrafluoroethylene tube graft with diameters of 26 to 40 mm, is the first DTA device to enter phase II trials in the United States and has been used worldwide for a host of thoracic pathologies. A multicenter prospective nonrandomized phase II study of the GORE TAG endoprosthesis was conducted at 17 sites. Enrollment was from September 1999 to May 2001. Preoperative workup included arteriography and spiral computed tomography scans of the chest, abdomen, and pelvis. Follow-up radiographs and computed tomography scans were obtained at 1, 6, and 12 months and yearly thereafter. A total of 139 (98%) of 142 patients had a successful implantation of the device. Inadequate arterial access was responsible for the 3 failures. The mean DTA size was 64.1 +/- 15.4 mm. Men slightly outnumbered women (57.7%), with an average age of 71 years, and 88% of the patients were white. Ninety percent were American Society of Anesthesiologists category III or IV. One device was used in 44% of patients, and 56% required two or more devices to bridge the thoracic aorta. The left subclavian artery was covered in 28 patients, with planned carotid-subclavian transposition. The procedure time averaged 150 minutes, estimated blood loss averaged 506 mL, intensive care unit stay averaged 2.6 days, and hospital stay averaged 7.6 days. Within 30 days, 45 (32%) patients had at least 1 major adverse event: 5 (4%) experienced a stroke, 4 (3%) demonstrated temporary or permanent paraplegia, 20 (14%) experienced vascular trauma or thrombosis, and 2 (1.5%) died. Mean follow-up was 24.0 months. Four patients had aneurysm-related deaths. Three patients underwent endovascular revisions for endoleak. No ruptures have been reported. Twenty wire fractures have been identified in 19 patients; 18 (90%) of these occurred in the longitudinal spine, and only 1 patient required treatment. At 2 years, aneurysm-related and overall survival rates are 97% and 75%, respectively. The GORE TAG thoracic endoprosthesis provides a safe alternative for the treatment of DTAs, with low mortality, relatively low morbidity, and excellent 2-year freedom from aneurysm-related death. Longitudinal spine fractures have so far been associated with rare clinical events.