Bypass Graft Placement Research Articles

Cavernous transformation of the portal vein in pancreatic cancer surgery\u2014venous bypass graft first

BackgroundIn recent years, several techniques have been introduced to allow safe oncologic resections of cancers of the pancreatic head. While resections of the mesenterico-portal axis became now a part of the routine treatment, patients with a cavernous transformation of the portal vein still pose a surgical challenge and are regularly deemed unresectable.ObjectiveHere, we describe a technique of initial venous bypass graft placement between the superior mesenteric vein or its tributaries and the portal vein before the resection of the pancreatic head. This approach avoids uncontrollable bleeding as well as venous congestion of the intestine with a continuous hepatic perfusion and facilitates oncologic resection of pancreatic head cancers. This technique, in combination with previously published resection strategies, enables tumor resection in locally advanced pancreatic head cancers.ConclusionsVenous bypass graft first operations facilitate and enable the resection of the pancreatic head cancers in patients with a cavernous transformation of the portal vein thus rendering these patients resectable.

Predictors associated with an increased prevalence of postimplantation syndrome after thoracic endovascular aortic repair for type B aortic dissection†.

The aim of this study was to identify patients who are at high risk of developing postimplantation syndrome (PIS) after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection. This retrospective study included 646 patients who underwent TEVAR for type B aortic dissection between January 2010 and December 2015 at the Guangdong General Hospital. PIS was defined as fever (>38°C) and leucocytosis (>12 000 μl-1) without evidence of infection. The PIS rate was calculated, and a multivariable logistic regression model was used to investigate the factors related to PIS. A total of 646 patients (58.8 ± 11.0 years, 87.9% men) were included in the analysis. PIS was diagnosed in 204 (31.6%) patients. Age <60 years [odds ratio (OR) 1.828, 95% confidence interval (CI) 1.277-2.619; P < 0.001), hypertension (OR 12.125, 95% CI 4.310-34.111; P < 0.001), >1 stent graft placed (OR 1.862, 95% CI 1.109-3.124; P = 0.011), arch vessel bypass (OR 2.107, 95% CI 1.397-3.176; P = 0.001) and Ankura stent graft placement (OR 1.951, 95% CI 1.298-2.933; P = 0.001) were positively associated with PIS, whereas statin use (OR 0.659, 95% CI 0.460-0.944; P = 0.023) was negatively associated with PIS in the multivariable logistic regression analysis based on a stepwise regression model. Age <60 years, comorbid hypertension, >1 stent graft placed, arch vessel bypass and Ankura stent graft placement emerged as independent predictors of PIS. Stepwise increases in the prevalence of PIS were found to depend on the number of independent predictors.

AIUM Practice Parameter for the Performance of Ultrasound Vascular Mapping for Preoperative Planning of Dialysis Access

AIUM Practice Parameter for the Performance of Ultrasound Vascular Mapping for Preoperative Planning of Dialysis Access

Single center experience of aortic bypass graft for aortic arch obstruction in children.

The purpose of this study is to access the outcomes of aortic bypass graft placement in children. This is a retrospective review of all children having aortic bypass graft placement for aortic arch obstruction for the first time between 1982 and 2013 at a single institution. The actuarial survival and the freedom from aortic arch reoperation were calculated and compared between the groups. Seventy consecutive children underwent aortic bypass graft placements. The median age and body weight at the operation were 14days and 3.6kg. There were 7 early deaths, 6 late deaths, and 7 heart transplants during the median follow-up of 10.8years (0.0-31.5years). The actuarial transplant free survival was 64.7% at 20years and the freedom from aortic arch reoperation was 50.5% at 10years. Between the children younger than 1year old and older than 1year old, there were significant differences in actuarial transplant free survival (56.4 vs. 100% at 15years, p=0.0042) and in the freedom from aortic arch reoperation (18.7 vs. 100% at 10years, p<0.001). The children who received aortic bypass graft larger than 16mm in size had no aortic arch reoperation at 15years. The aortic bypass graft placement for aortic arch obstruction can be done with low mortality and morbidity for children who can receive bypass graft larger than 16mm in size. However, it should be avoided for the neonates and infants except selected situations.

Ischemic Left Ventricular Perforation Covered by a Thrombus in a Patient Presenting with Cerebral Ischemia: Importance of Time-Sensitive Performance and Adequate Interpretation of Bedside Transthoracic Echography.

If myocardial infarction remains silent, only clinical signs of complications may unveil its presence. Life-threatening complications include myocardial rupture, thrombus formation, or arterial embolization. In the presented case, a 76-year-old patient was admitted with left-sided hemiparesis. In duplex sonography, a critical stenosis of the right internal carotid artery was identified and initially but retrospectively incorrectly judged as the potential cause for ischemia. During operative thromboendarterectomy, arterial embolism of the right leg occurred coincidentally, more likely pointing towards a cardioembolic origin. Percutaneous interventions remained unsuccessful and local fibrinolysis was applied. Delayed bedside echocardiography by an experienced cardiologist demonstrated a discontinuity of the normal myocardial texture of the left ventricular apex together with an echodense, partly floating structure merely attached by a thin bridge not completely sealing the myocardial defect, accompanied by pericardial effusion. The patient was immediately transferred to emergency cardiac surgery with extirpation of the thrombus, aortocoronary bypass graft placement, and aneurysmectomy. This didactic case reveals decisive structural shortcomings in patient's admission and triage processes and underlines, if performed timely and correctly, the value of transthoracic echocardiography as a noninvasive and cost-effective tool allowing immediate decision-making, which, in this case, led to the correct but almost fatally delayed diagnosis.

V1857 CHALLENGING CASES OF ROBOTIC ASSISTED RADICAL CYSTECTOMY FOLLOWING RADIOTHERAPY OR VASCULAR SURGERY

You have accessJournal of UrologyBladder Oncology1 Apr 2013V1857 CHALLENGING CASES OF ROBOTIC ASSISTED RADICAL CYSTECTOMY FOLLOWING RADIOTHERAPY OR VASCULAR SURGERY Scott Leslie, Hamed Ahmadi, Andre Luis de Castro Abreu, Andre K Berger, R James Yu, Sheaumei Tsai, Steve Dong, Adrian S Fairey, Raed A Azhar, Mihir M Desai, Inderbir S Gill, and Monish Aron Scott LeslieScott Leslie Los Angeles, CA More articles by this author , Hamed AhmadiHamed Ahmadi Los Angeles, CA More articles by this author , Andre Luis de Castro AbreuAndre Luis de Castro Abreu Los Angeles, CA More articles by this author , Andre K BergerAndre K Berger Los Angeles, CA More articles by this author , R James YuR James Yu Los Angeles, CA More articles by this author , Sheaumei TsaiSheaumei Tsai Los Angeles, CA More articles by this author , Steve DongSteve Dong Los Angeles, CA More articles by this author , Adrian S FaireyAdrian S Fairey Los Angeles, CA More articles by this author , Raed A AzharRaed A Azhar Los Angeles, CA More articles by this author , Mihir M DesaiMihir M Desai Los Angeles, CA More articles by this author , Inderbir S GillInderbir S Gill Los Angeles, CA More articles by this author , and Monish AronMonish Aron Los Angeles, CA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2276AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Robotic-assisted radical cystectomy (RARC) is increasingly utilized for the management of invasive bladder cancer. However, the feasibility of RARC in the setting of prior radiotherapy and vascular surgery has yet to be determined. We describe the technical challenges associated with these cases and compare outcomes with the entire RARC cohort at the University of Southern California. METHODS Between August 2009 and October 2012 58 patients underwent RARC at our institution. We compared the outcomes of 5 patients who had prior radiotherapy or vascular surgery with the rest of the cohort. The technique of RARC has been standardized at USC, and includes an extended pelvic lymph node dissection and intracorporeal urinary diversion. Demographic, perioperative and pathological parameters were collected. RESULTS All five patients were male with a median age of 75. Three patients received radiotherapy for prostate cancer and two patients with prior vascular surgery including abdominal aortic aneurysm repair in one patient and aorto-bifemoral bypass graft placement in the other one. Of the 5 patients, median EBL was 250 ml (range: 60 - 250), median operative time was 7 hrs (range: 6 - 8.9) and median hospital length of stay was 8 days (range: 5 - 19). There were no transfusions. One patient had a Clavien grade 1 and one patient had Clavien grade 3a complication. Comparing these 5 patients with the entire group undergoing RARC, there was no fifference in complications, estimated blood loss, or hospital length of stay. CONCLUSIONS RARC in the setting of prior radiotherapy or vascular surgery is safe and feasible. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e762 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Scott Leslie Los Angeles, CA More articles by this author Hamed Ahmadi Los Angeles, CA More articles by this author Andre Luis de Castro Abreu Los Angeles, CA More articles by this author Andre K Berger Los Angeles, CA More articles by this author R James Yu Los Angeles, CA More articles by this author Sheaumei Tsai Los Angeles, CA More articles by this author Steve Dong Los Angeles, CA More articles by this author Adrian S Fairey Los Angeles, CA More articles by this author Raed A Azhar Los Angeles, CA More articles by this author Mihir M Desai Los Angeles, CA More articles by this author Inderbir S Gill Los Angeles, CA More articles by this author Monish Aron Los Angeles, CA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Repeat Revascularization After PCI

In the modern era of percutaneous coronary interventions (PCI), drug-eluting stents are commonly used to reduce the risk of restenosis.1 With the development of second-generation drug-eluting stents, there has been a significant reduction in the incidence of restenosis with rates ranging from 6% to 10% in most clinical trials,2 with emerging evidence for a reduction in late myocardial infarction (MI). Numerically, the rate of clinical restenosis is now close to the rate of MI, 1 to 2 years after a PCI.1 However, among patients with multivessel coronary artery disease (CAD) there remains uncertainty regarding the risk of restenosis, stent thrombosis (ST), and possible late MI.3 Interventional cardiologists are, therefore, faced with a dilemma in trading off the various risks of adverse events (such as the need for repeat revascularization and periprocedural MI) during decision-making for the most appropriate use of PCI. Article see p 772 In this issue of Circulation: Cardiovascular Interventions , Stolker and colleagues4 report on the use and need for repeat revascularization in a large contemporary registry. The EVENT Registry was a prospective observational registry designed to study PCI in clinical practice in 55 US centers. A total of 10,144 patients were included; ≈5%, ST-segment–elevation myocardial infarction (STEMI); 40% other acute coronary syndromes; and 49% with stable CAD. Analysis of 4 main outcomes was undertaken; ST, target lesion revascularization (TLR), target vessel revascularization, or other vessel revascularization. TLR was defined as repeat PCI or bypass graft placement for restenosis at the lesion treated during index PCI, or occurring within 5 mm of the PCI site (edge effect) as determined clinically by the investigator at each site. Target vessel revascularization …

A Unique Technique for Intentional Occlusion of an Abdominal Aortic Aneurysm

We report the case of a 78-year-old man with severe chronic obstructive pulmonary disease, aortoiliac occlusive disease, and a 7-cm infrarenal abdominal aortic aneurysm (AAA). He also had a 5-cm right common iliac artery (CIA) aneurysm (CIAA) with right external iliac artery occlusion (Fig 1). The patient had undergone axillobifemoral bypass graft placement 10 years prior for disabling claudication. We describe the use of an infrarenal aortouniiliac graft and subsequent intentional graft occlusion as an endovascular solution. Under locoregional anesthesia, percutaneous access for periprocedural imaging was obtained via the right brachial artery. A left retroperitoneal incision allowed access to the left CIA. The right internal iliac artery and CIAA were coil embolized. A Renu aortoiliac graft (Cook Medical, Bloomington, Ind) was deployed via the left CIA. The endograft was intentionally occluded with a Cook Zip occluder, and two Amplatzer plugs (AGA Medical, Plymouth, Minn). The left CIA was surgically ligated distal to the endograft, excluding both aneurysms. The left hypogastric artery maintained retrograde perfusion via the previously placed axillobifemoral graft (Fig 2). The patient tolerated the procedure and remains asymptomatic 6 months after surgery, with demonstrated occlusion of the infrarenal aorta, the AAA, and CIAA, and no enlargement of either aneurysm sac. The axilobifemoral bypass remains patent (Fig 3). We have described a unique case of intentional endovascular aortic occlusion for the treatment of an AAA in the setting of severe aortoiliac disease and a previous axillobifemoral bypass graft. This technique may be useful in select high-risk AAA patients with similar anatomic circumstances.

Thrombospondin-2 Gene Silencing in Human Aortic Smooth Muscle Cells Improves Cell Attachment

Despite decades of research, anastomotic intimal hyperplasia remains a major cause of delayed prosthetic arterial graft failure. Previously, we reported profound upregulation of thrombospondin-2 (TSP-2) mRNA in neointimal smooth muscle cells after prosthetic arterial bypass graft placement. TSP-2 is an antiangiogenic matricellular protein with specific functions yet unknown. In this study, we hypothesized that inhibition of TSP-2 in human aortic smooth muscle cells (HAoSMCs) would reduce cell proliferation and migration in vitro, providing a therapeutic target to mitigate intimal hyperplasia. HAoSMCs were transfected with TSP-2 small interfering ribonucleic acid (siRNA) using a commercial transfection reagent. Gene silencing was evaluated using semiquantitative real-time polymerase chain reaction. ELISA was used to measure TSP-2 protein levels in cell culture supernatants. Cell migration and proliferation were assessed using scratch wound assays and alamar blue assays, respectively. Attachment assays were performed to assess the effect of TSP-2 silencing on HAoSMC adhesion to fibronectin. TSP-2 siRNA achieved consistent target gene silencing at 48 hours post-transfection in HAoSMCs. This single transfection allowed suppression of TSP-2 protein expression for more than 30 days. TSP-2 gene silencing did not affect HAoSMC migration or proliferation. MMP-2 levels were also unaffected by changes in TSP-2 protein levels. However, HAoSMC attachment to fibronectin improved significantly in cells treated with TSP-2 siRNA. siRNA-mediated TSP-2 silencing of human aortic HAoSMCs improved cell attachment but had no effect on cell migration or proliferation. The effect on cell attachment was unrelated to changes in MMP activity.

Endovascular Occlusion of a Ruptured Popliteal Artery Aneurysm

Popliteal artery aneurysms are the most common of the peripheral aneurysms. Rupture is a rare complication of these aneurysms. Here we present a case of a ruptured popliteal aneurysm in a patient with severe joint disease and immobility due to rheumatoid arthritis. The condition was treated endovascularly with an Amplatzer arterial occlusion device. The aneurysm was successfully thrombosed without inducing critical limb ischemia, as the distal popliteal was chronically occluded. Ligation of peripheral aneurysms is an infrequent treatment without simultaneous bypass graft placement. Endovascular occlusion of ruptured popliteal aneurysms should be considered a valid therapeutic strategy where exclusion bypass is not required due to distal arterial occlusion.

Pyelovesical Bypass Graft for Palliative Management of Malignant Ureteric Obstruction: Optimizing the Technique by Percutaneous Access to the Bladder Using a Split Amplatz Sheath

To introduce a simple modification to the original technique of pyelovesical bypass graft placement to make the procedure more minimally invasive. During the study period 2 patients with malignant ureteric obstruction underwent pyelovesical bypass graft placement using Detour stent (Mentor-Porges). The technique simply comprised tract dilatation of the previously placed percutaneous nephrostomy to place the proximal end of the graft in the renal collecting system, making a subcutaneous tunnel from a 1-cm suprapubic incision to the flank area, percutaneous access to the bladder under fluoroscopic guide and placement of the distal end of the stent into the bladder through a split Amplatz sheath. The operative outcome was analyzed prospectively. Both patients tolerated the procedures well with no intra- and postoperative complications. Renal function remained stable during the follow-up period with acceptable urine output through the urethra. Abdominal wall complications such as fistula formation or pain along the subcutaneous tract as well as stent encrustation did not occur during the follow-up period. Despite our small sample size and short follow-up period, percutaneous access to the bladder using a split Amplatz sheath during placement of the Detour stent, may be considered as a promising simple modification to optimize the technique by obviating the need for open cystostomy incision.

Continuation of trastuzumab-based therapy beyond disease progression in metastatic breast cancer patients – a retrospective one center analysis

Despite decades of research, anastomotic intimal hyperplasia remains a major cause of delayed prosthetic arterial graft failure. Previously, we reported profound upregulation of thrombospondin-2 (TSP-2) mRNA in neointimal smooth muscle cells after prosthetic arterial bypass graft placement. TSP-2 is an antiangiogenic matricellular protein with specific functions yet unknown. In this study, we hypothesized that inhibition of TSP-2 in human aortic smooth muscle cells (HAoSMCs) would reduce cell proliferation and migration in vitro, providing a therapeutic target to mitigate intimal hyperplasia.HAoSMCs were transfected with TSP-2 small interfering ribonucleic acid (siRNA) using a commercial transfection reagent. Gene silencing was evaluated using semiquantitative real-time polymerase chain reaction. ELISA was used to measure TSP-2 protein levels in cell culture supernatants. Cell migration and proliferation were assessed using scratch wound assays and alamar blue assays, respectively. Attachment assays were performed to assess the effect of TSP-2 silencing on HAoSMC adhesion to fibronectin.TSP-2 siRNA achieved consistent target gene silencing at 48 hours post-transfection in HAoSMCs. This single transfection allowed suppression of TSP-2 protein expression for more than 30 days. TSP-2 gene silencing did not affect HAoSMC migration or proliferation. MMP-2 levels were also unaffected by changes in TSP-2 protein levels. However, HAoSMC attachment to fibronectin improved significantly in cells treated with TSP-2 siRNA.siRNA-mediated TSP-2 silencing of human aortic HAoSMCs improved cell attachment but had no effect on cell migration or proliferation. The effect on cell attachment was unrelated to changes in MMP activity.

Totally Endoscopic Coronary Artery Bypass Grafting on the Arrested Heart

In the late 1990s, totally endoscopic coronary artery bypass grafting was successfully introduced into the heart surgery armamentarium using robotic techniques. Surgeons have applied the da Vinci telemanipulation system in order to develop completely endoscopic placement of internal mammary artery bypass grafts, mainly to the left anterior descending artery system. Multivessel procedures are currently under development. These operations can be carried out on the arrested heart using remote access perfusion and cardioplegic arrest via ascending aortic balloon occlusion. Another option is performing procedures on the beating heart using an endostablilizer and local coronary artery occlusion. In this review, the technique and specific aspects of the arrested heart version of totally endoscopic coronary artery bypass grafting are outlined.

The Hybrid Total Arch Repair: Brachiocephalic Bypass and Concomitant Endovascular Aortic Arch Stent Graft Placement

Repair of aortic arch aneurysm is technically demanding, requiring complex circulatory management. Very large atherosclerotic saccular aneurysms of the arch are grave markers of extensive arch and brachiocephalic atheromatous disease and represent high surgical risks for perioperative neurologic complications. Operative morbidity and mortality may be prohibitive with traditional surgical intervention. We described our experience with a hybrid procedure for total arch repair with a brachiocephalic bypass with a trifurcated graft followed by concomitant placement of a stent graft in the arch. Since June 2005, we have performed the hybrid total arch repair in eight patients. A retrospective review was performed to evaluate the new technique. The mean age of the patients was 67 years with a mean aneurysm size of 8 cm (range, 4.4 to 10 cm). Significant comorbidities included carotid stenosis, chronic renal insufficiency, peripheral vascular disease, hypertension, and coronary artery disease. Two patients had previous Abdominal aortic aneurysm (AAA) repairs. Three patients had previous sternotomy for type A dissection, ascending aortic aneurysm repair, and coronary artery bypass grafting. Transesophageal echocardiogram demonstrated grade IV or V atheromatous disease in the arch and ascending aorta. Stent grafts were deployed antegrade directly into the ascending aorta in three patients and retrograde from the femoral artery in five patients. Technical success with complete aneurysmal exclusion was achieved in all patients (100%). At a mean follow-up period of 11.7 months, there was no incidence of endoleak. There was one death resulting from a perioperative myocardial infarction (first patient). Documented perioperative neurologic events (stroke) occurred in two patients, with both patients demonstrating no residual deficit at the time of discharge. Saccular arch aneurysms can be technically treated by total arch repair with brachiocephalic bypass and concomitant aortic arch stent graft placement. Hybrid arch repair provides an alternative to patients otherwise considered prohibitively high risk for traditional open arch repair.

Invited Commentary: The Hybrid Total Arch Repair: Brachiocephalic Bypass and Concomitant Endovascular Aortic Arch Stent Graft Placement

Journal of Cardiac SurgeryVolume 22, Issue 2 p. 103-104 Invited Commentary: The Hybrid Total Arch Repair: Brachiocephalic Bypass and Concomitant Endovascular Aortic Arch Stent Graft Placement Grayson H. Wheatley III M.D., Grayson H. Wheatley III M.D. Arizona Heart Institute, Phoenix, AZSearch for more papers by this author Grayson H. Wheatley III M.D., Grayson H. Wheatley III M.D. Arizona Heart Institute, Phoenix, AZSearch for more papers by this author First published: 02 March 2007 https://doi.org/10.1111/j.1540-8191.2007.00377.xRead the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume22, Issue2March/April 2007Pages 103-104 RelatedInformation

On-Pump and Off-Pump Coronary Artery Bypass Grafting

Surgery for coronary artery disease is known as coronary artery bypass grafting (CABG). It was one of the landmark operations in the history of cardiac surgery that rescued millions of people afflicted by coronary artery disease. It was first performed by Kolesov,1 was popularized by Favaloro,2 and is still the leading heart operation performed today. Current reasons for performing CABG are the presence of 3-vessel disease (all the 3 major arteries to the heart are blocked), left main coronary artery disease (the main artery itself is critically narrowed), and 3-vessel disease in diabetics. It also is used for patients with severely depressed heart function and for patients who need surgery for heart conditions in addition to coronary artery disease (such as replacement of valves or reconstruction of the heart muscle). Similar to a detour on a highway in the setting of a roadblock, CABG involves the strategic placement of bypass grafts that will provide an alternative route for the blood to flow around the blockage (Figure). These bypass grafts are composed of other arteries and veins from the body of the patient that are harvested only when they are numerous in their location or their function in their primary location can be safely and effectively taken over by …

Mesenteric Ischemia

Mesenteric ischemia is a morbid, potentially life-threatening disease that is associated with a relatively high mortality, often due to its late diagnosis. Currently, the incidence of mesenteric ischemia in the United States is low; however, the incidence is predicted to increase because of the aging population. Therefore, whether the presentation is acute or chronic in nature, the challenge for the physician remains early diagnosis through a high index of suspicion based on vague and often atypical presentations. Surgical intervention remains the mainstay of therapy. Despite ongoing investigations of the different treatment options, including single vs multivessel bypass, antegrade vs retrograde graft placement, autogenous vs prosthetic conduits, and endovascular vs open surgical repair, many questions remain unanswered. This review summarizes the clinical presentation, diagnosis, and treatment options, including both open and endovascular approaches, for acute and chronic mesenteric ischemia.

Case 83: Multifocal Fibrosclerosis with Mediastinal-Retroperitoneal Involvement

A 72-year-old man with a history of congestive heart failure, malignant hypertension, and peripheral and coronary vascular disease was admitted to the hospital 4 days after onset of acute dyspnea and lower-extremity edema. He underwent coronary catheterization; after this procedure, his serum creatinine levels increased from 1.6 to 5.9 mg/dL (141.4–521.6 mol/L). He was subsequently referred for renal and aortic magnetic resonance (MR) imaging to allow more comprehensive evaluation of renal and vascular disease. Prior to admission, the patient had undergone coronary artery bypass graft placement for triple-vessel coronary artery disease (5 years previously) and right carotid endarterectomy (1 year previously). Pathologic specimens of the carotid artery showed dense fibrous tissue and chronic inflammation surrounding the vessel wall.

Critical Limb Ischemia: Hybrid MR Angiography Compared with DSA

To compare a hybrid magnetic resonance (MR) angiography protocol with selective digital subtraction angiography (DSA) in patients with critical limb ischemia. The study was approved by the institutional review board, and written consent was obtained from all patients. Pretreatment DSA and hybrid MR angiography were performed in 19 consecutive patients (15 men, four women; mean age, 69.8 years; range, 44-86 years). Hybrid MR angiography included submillimeter dual-phase three-dimensional gadolinium-enhanced MR angiography in lower calf and foot, and four-station bolus-chase MR angiography in pelvis, thigh, and upper calf. Three readers identified the target lesion and inflow and outflow segments and determined treatment (bypass graft placement, percutaneous transluminal angioplasty, conservative management, amputation). Results of interobserver and intermethod comparisons were expressed as percentage of agreement and 95% confidence interval (CI). On hybrid MR angiograms, no substantial venous overlay was present and image quality was excellent or adequate in 18 (95%) of 19 limbs. Readers 1, 2, and 3 selected the identical target lesion on the DSA image and the MR angiogram in 18, 17, and 18 of 18 comparable limbs, respectively. Mean percentage of agreement for readers 1 and 3 was 100% (95% CI: 81%, 100%) and for reader 2 was 94% (95% CI: 73%, 100%). Agreement of all three readers was superior with use of MR angiography for determination of inflow segments (13 [72%] of 18 limbs) and outflow segments (17 [94%] of 18 limbs), compared with agreement with use of DSA (13 [68%] of 19 inflow segments, 10 [53%] of 19 outflow segments). Agreement in therapy decisions was higher with DSA (15 [79%] of 19) than with MR angiography (11 [61%] of 18). Preliminary data strongly support the combination of submillimeter dual-phase MR angiography in lower calf and foot with four-station bolus-chase MR angiography to extend the utility of MR angiography to patients with critical limb ischemia.

Evaluation of platelet deposition and neointimal hyperplasia of heparin-coated small-caliber ePTFE grafts in a canine femoral artery bypass model 1

Introduction Bypass graft failure due to acute thrombosis and intimal hyperplasia remains a major challenge in small-diameter vascular prosthetic graft reconstruction. Heparin has been shown to prevent thrombus formation and inhibit intimal antithrombotic in animal studies. In this study, we evaluated the effect of small-caliber heparin-coated expanded polytetrafluoroethylene (ePTFE) grafts on platelet deposition and intimal hyperplasia in a canine model of femoral artery bypass grafting. Methods Nine adult greyhound dogs underwent placement of bilateral femorofemoral artery bypass grafts with ePTFE grafts (4 mm diameter and 7 cm long). In each animal, a heparin-coated ePTFE graft was placed on one side while a noncoated graft was placed on the contralateral side which served as the control. Platelet deposition was measured by autologous 111indium-labeling and scintillation camera imaging analysis in 24 h. The graft patency was assessed at 4 weeks following the bypass. The effect of intimal hyperplasia was assessed with histological and morphometric analysis. Results Platelet deposition on the heparin-coated grafts at 24 h was significantly reduced by 72% as compared to controls ( P = 0.001). The patency rate was 44% in control grafts and 89% in heparin-coated grafts. There was a significant reduction of graft intimal hyperplasia at both proximal (0.38 ± 0.21 mm 2) and distal (0.19 ± 0.06 mm 2) anastomoses in the heparin-coated grafts as compared with proximal (1.01 ± 0.28 mm 2) and distal (0.42 ± 0.01 mm 2) anastomoses in the untreated control grafts, respectively ( P < 0.05). Heparin coating significantly reduced graft neointimal hyperplasia at patent graft anastomoses by 55–72% as compared to controls. Conclusions These data demonstrate that heparin coating of ePTFE significantly reduced early platelet deposition and inhibited anastomotic neointimal hyperplasia. Moreover, small-caliber heparin-coated ePTFE graft significantly increased graft patency in a canine femoral artery bypass model. This may represent a promising treatment strategy for improving the clinical performance of small-caliber prosthetic vascular grafts.