Limb Occlusion Research Articles

New Technique for Measuring Limb Occlusion Pressure Facilitates Personalized Tourniquet Systems

Category: Basic Sciences/Biologics Introduction/Purpose: Optimal tourniquet safety depends on accurately determining the minimum pressure necessary to achieve a bloodless surgical field, known as a patient’s limb occlusion pressure (LOP). However, LOP is not yet routinely measured in all patients due to limitations of current techniques. We have evaluated a novel technique for measuring the LOP through the tourniquet cuff that overcomes many limitations of current LOP measurement techniques. Methods: The new technique of measuring LOP involves the use of unique dual-purpose disposable tourniquet cuffs along with a tourniquet instrument containing LOP calculation sensors and software. A randomized crossover multicenter trial with 143 pre-surgical or post-surgical patients enrolled in the study. Pneumatic cuffs were applied to the non-operative upper and lower limbs and LOP was measured using the new technique and the Doppler ultrasound technique. For each patient a set of four LOP measurements was taken, using the new technique (experimental) and the Doppler technique (control) on one upper and one lower limb. Blinding was achieved during LOP measurement by using two experimenters and blinding the experimenter who measured the LOP using Doppler ultrasound from the LOP reading using the new automatic technique. Participants were blinded from all LOP measurement results by keeping the displays of measurement equipment out of their view. Results: The differences between the new technique and Doppler technique were neither statistically nor clinically significant and the new technique is as robust as the Doppler technique. The results of this study can be used to develop personalized tourniquet systems consisting of unique dual-purpose cuffs connected to instruments suitable for measuring tourniquet LOP with the new measurement technique. The simplicity, effectiveness, and accuracy of this technique should lead to broader clinical usage and acceptance of LOP measurement, thus leading to safer, personalized pressures in surgical tourniquet applications. Conclusion: The new technique is equally robust as the Doppler technique. Both techniques worked successfully in the 252 limbs from which usable data was collected. Of the 34 limbs for which there were data collection errors or exclusion, only two measurements were excluded because of an instrument error using the automatic technique compared to one measurement excluded because of a Doppler technique measurement error.

A multicenter 12-month experience with a new iliac side-branched device for revascularization of hypogastric arteries

ObjectiveThe aim of this study was to investigate the 1-year safety and efficacy of a new iliac side-branched device (IBD) for revascularization of the hypogastric arteries. MethodsPatients receiving the E-liac (Jotec GmbH, Hechingen, Germany) side-branched device at six German vascular centers either as a stand-alone procedure or in combination with abdominal aortic aneurysm exclusion were included in a prospectively created data bank. Collected data were analyzed for baseline characteristics, procedural events, and clinical follow-up; variables included endoleaks, reinterventions, and internal iliac artery (IIA) patency. ResultsBetween January 2012 and January 2015, a total of 70 patients (69 men [98.6%]) with a median age of 74 years (range, 51-87 years) were consecutively treated; 66 patients had aneurysmatic disease of the iliac arteries, 2 patients had a para-anastomotic aneurysm after aortobi-iliac reconstruction, and another 2 patients had a type Ib endoleak after endovascular aneurysm repair. A total of 82 IIAs were revascularized, 12 bilaterally. Technical success was achieved in 100% (82/82) of the revascularized IIAs. All IBDs were patent at the end of the procedure. No instances of myocardial infarction, stroke, conversion to open repair, mesenteric or spinal cord infarction, or buttock necrosis were observed. There was one perioperative death (1.4%) in a 70-year-old patient with intraoperative gastrointestinal bleeding leading to multiple organ failure, which resulted in the patient's death on the fifth postoperative day. Within 30 days, one symptomatic occlusion of a treated common iliac artery (CIA) was observed. In two other patients, an asymptomatic kinking of the CIA segment of the IBD was revealed in the predischarge follow-up duplex ultrasound examination and corrected with relining. Median follow-up was 12 months (range, 6-16 months). One patient was lost during the follow-up period. Survival at 1 year was 98.5% with all IIAs remaining patent, whereas two CIA and two external iliac artery limb occlusions occurred. According to life-table analysis, the freedom from occlusion in a patient was 92% at 1 year, and freedom from type I endoleak was 87% at 1 year. ConclusionsThis first ever 1-year study reports the results with the new E-liac device and shows that it can be safely applied for the treatment of aortoiliac aneurysmatic disease with low reintervention rates and high patency rates. Long-term data are needed to confirm the durability of the device.

Extensive ischemic ulcers due to limb occlusion after endovascular aneurysm repair: a case report.

IntroductionLimb occlusion after endovascular aneurysm repair (EVAR) is a well-known complication. However, extensive ischemic ulcers due to limb occlusion are extremely rare.Case descriptionWe report a rare case of extensive ischemic ulcers that developed seven months after EVAR in an 85-year-old Japanese man. He had been taking appropriate anticoagulant therapy because of paroxysmal atrial fibrillation. Angiography showed a left limb occlusion and superficial femoral artery (SFA) chronic total occlusion (CTO), and intravascular ultrasound showed limb kinking. Endovascular therapy (EVT) was performed, and stent placement was used to cover a large amount of thrombi and correct the limb kinking, leading to complete recovery of left limb blood flow. After additional EVT was performed for the SFA CTO, outflow improved and the ulcers healed completely.Discussion and evaluationIt seemed that the combination of poor inflow and poor outflow led to limb thrombosis.ConclusionsHere, we describe an extremely rare case of extensive ischemic ulcers due to limb occlusion after EVAR. Patients should undergo careful follow-up after EVAR to monitor blood flow to the lower extremities. Additionally, the early detection and correction of limb kinking and poor outflow are essential to prevent the development of ischemic ulcers.

Application and effect observation of hybrid aortic stent grafts for endovascular repair in the treatment of complicated infrarenal abdominal aortic aneurysm

To evaluate the effectiveness of the hybrid graft technique for complicated infrarenal abdominal aortic aneurysms (AAAs). The clinical data of 183 patients who underwent endovascular aneurysm repair (EVAR) for AAA with challenging anatomy at Zhongshan Hospital Affiliated to Shanghai Fudan University from 2010 to 2015 were retrospectively analyzed. Endografts were divided into two groups: Hybrid Group (28 cases) used more than one type of stent graft, and Standard Group (110 cases) used only one stent graft type. Patients were recommended to undergo CT angiography at 1, 3, 6, 12 month after the procedure. Clinical data were analyzed with a focus on postoperative hospital stay, endoleak, limb occlusion, complications of approach, complications of system, converted to open operation and secondary intervention. Technical success was achieved in all patients in both groups. Compared with hybrid group and standard group, there was no difference in postoperative hospital stay ((5.35±2.99) and (5.92±3.70) days, t=0.753, P>0.05). During the follow up, there was no difference in endoleak (10.7% and 18.2%), limb graft occlusion (3.6% and 10.9%), complications of approach (0 and 1.8%), complications of system (7.1% and 0.9%), converted to open operation (0 and 0.9%) between two groups (χ(2)=0.896, 1.408, 0.517, 4.078, 0.256, all P>0.05). However, there was statistically significant difference in secondary intervention between two groups (3.6% and 19.1%, 2=4.011, P<0.05). The use of hybrid stent graft in patients with unfavorable neck and iliac artery anatomy AAA is feasible, and it could improve the postoperative outcomes such as secondary intervention rate.

Final results of the Endurant Stent Graft System in the United States regulatory trial

To report the 5-year outcomes from the Endurant Stent Graft System in the U.S. regulatory trial (bifurcated Endurant; Medtronic Santa Rosa, Calif). The study was a prospective, multicenter, regulatory trial performed at 26 U.S. sites. From June 2008 to April 2009, 150 patients with abdominal aortic aneurysms (AAAs) were treated with the Endurant bifurcated graft. The main inclusion criteria included AAA diameter >5cm (or 4-5cm in diameter where the size increased more than 5mm within the previous 6months), neck length ≥10mm, and neck angulation ≤60 degrees. A clinical events committee adjudicated all untoward events, and a core laboratory reviewed available imaging at 1, 6, 12, 24, and 60months. Outcomes were compared with the Talent enhanced Low Profile System (eLPS) study for regulatory purposes. At 5years, clinical follow-up was available on 94% and imaging on 87% of 101 eligible patients. At 5years, all-cause mortality estimate by Kaplan-Meier was 17.7%, and freedom from aneurysm-related mortality was 99.2%. One aneurysm-related mortality was noted in a patient that refused treatment for a type I endoleak and died in year 4 from rupture. There were no endograft migrations, fractures, or open conversions. At 5years, endoleaks were identified in 7/83 patients (8.4%) and included six type II endoleaks and one of indeterminate origin. Maximum AAA diameter decreased by more than 5mm in 53/83 patients (63.9%), remained stable in 25/83 (30.1%), and increased >5mm in 5/83 (6.0%). Eighteen AAA-related secondary interventions were required in 15 patients (11%): 12 for endoleak management, 4 for limb occlusions, 1 for stenosis, and 1 for thromboembolism. Four of 5 limb occlusions reported were in the first 6months. Survival and reintervention rates were better than the Talent eLPS study, which was conducted under similar inclusion exclusion criteria. The 5-year outcomes of the Endurant Stent Graft System in the U.S. regulatory trial continue to be positive. The device appears to be durable with limited adverse events through 5years. Comparison with an older generation device suggests improving outcomes with newer devices.

Strategies to Approaching Lower Limb Occlusions

Endovascular management of chronic total occlusions (CTO) can be challenging both from decision-making and technical perspectives. Successful treatment and management of a CTO requires the operator to have an understanding of the salient imaging findings, a thorough knowledge of the various technical challenges of the procedure, and comprehension of the importance and necessity of long-term clinical management. This article outlines a general approach to endovascular management of lower limb CTOs and discusses indications, techniques, potential complications, and therapeutic options of the procedure.

Dangerous Pressurization and Inappropriate Alarms during Water Occlusion of the Expiratory Circuit of Commonly Used Infant Ventilators.

BackgroundNon-invasive continuous positive airways pressure is commonly a primary respiratory therapy delivered via multi-purpose ventilators in premature newborns. Expiratory limb occlusion due to water accumulation or ‘rainout’ from gas humidification is a frequent issue. A case of expiratory limb occlusion due to rainout causing unexpected and excessive repetitive airway pressurisation in a Draeger VN500 prompted a systematic bench test examination of currently available ventilators.ObjectiveTo assess neonatal ventilator response to partial or complete expiratory limb occlusion when set to non-invasive continuous positive airway pressure mode.DesignSeven commercially available neonatal ventilators connected to a test lung using a standard infant humidifier circuit with partial and/or complete expiratory limb occlusion were examined in a bench test study. Each ventilator was set to deliver 6 cmH2O in non-invasive mode and respiratory mechanics data for 75%, 80% and 100% occlusion were collected.ResultsSeveral ventilators responded inappropriately with complete occlusion by cyclical pressurisation/depressurisation to peak pressures of between 19·4 and 64·6 cm H2O at rates varying between 2 to 77 inflations per minute. Tidal volumes varied between 10·1 and 24·3mL. Alarm responses varied from ‘specific’ (tube occluded) to ‘ambiguous’ (Safety valve open). Carefusion Avea responded by continuing to provide the set distending pressure and displaying an appropriate alarm message. Draeger Babylog 8000 did not alarm with partial occlusions and incorrectly displayed airways pressure at 6·1cmH2O compared to the measured values of 13cmH2O.ConclusionsThis study found a potential for significant adverse ventilator response due to complete or near complete expiratory limb occlusion in CPAP mode.

Peripheral venous distension elicits a blood pressure raising reflex in young and middle-aged adults.

Distension of peripheral veins in humans elicits a pressor and sympathoexcitatory response that is mediated through group III/IV skeletal muscle afferents. There is some evidence that autonomic reflexes mediated by these sensory fibers are blunted with increasing age, yet to date the venous distension reflex has only been studied in young adults. Therefore, we tested the hypothesis that the venous distension reflex would be attenuated in middle-aged compared with young adults. Nineteen young (14 men/5 women, 25 ± 1 yr) and 13 middle-aged (9 men/4 women, 50 ± 2 yr) healthy normotensive participants underwent venous distension via saline infusion through a retrograde intravenous catheter in an antecubital vein during limb occlusion. Beat-by-beat blood pressure, muscle sympathetic nerve activity (MSNA), and model flow-derived cardiac output (Q), and total peripheral resistance (TPR) were recorded throughout the trial. Mean arterial pressure (MAP) increased during the venous distension in both young (baseline 83 ± 2, peak 94 ± 3 mmHg; P < 0.05) and middle-aged adults (baseline 88 ± 2, peak 103 ± 3 mmHg; P < 0.05). MSNA also increased in both groups [young: baseline 886 ± 143, peak 1,961 ± 242 arbitrary units (AU)/min; middle-aged: baseline 1,164 ± 225, peak 2,515 ± 404 AU/min; both P < 0.05]. TPR (P < 0.001), but not Q (P = 0.76), increased during the trial. However, the observed increases in blood pressure, MSNA, and TPR were similar between young and middle-aged adults. Additionally, no correlation was found between age and the response to venous distension (all P > 0.05). These findings suggest that peripheral venous distension elicits a pressor and sympathetic response in middle-aged adults similar to the response observed in young adults.

Protocol for a prospective randomized controlled trial of recipient remote ischaemic preconditioning in orthotopic liver transplantation (RIPCOLT trial).

Ischaemic reperfusion (IR) injury is a major cause of graft loss, morbidity and mortality following orthotopic liver transplantation (OLT). Demand for liver transplantation has resulted in increasing use of marginal grafts that are more prone to IR injury. Remote ischaemic preconditioning (RIPC) reduces IR injury in experimental models, but recipient RIPC has not been evaluated clinically.MethodsA single-centre double-blind randomized controlled trial (RCT) is planned to test the hypothesis that recipient RIPC will reduce IR injury. RIPC will be performed following recipient anaesthetic induction but prior to skin incision. The protocol involves 3 cycles of 5 min of lower limb occlusion with a pneumatic tourniquet inflated to 200 mmHg alternating with 5 min of reperfusion. In the control group, the sham will involve the cuff being placed on the thigh but without being inflated.The primary endpoint is ability to recruit patients to the trial and safety of RIPC. The key secondary endpoint is a reduction in serum aspartate transferase levels on the third post-operative day.DiscussionRIPC is a promising strategy to reduce IR injury in liver transplant recipients as there is a clear experimental basis, and the intervention is both inexpensive and easy to perform. This is the first trial to investigate RIPC in liver transplant recipients.Trial registrationClinicaltrials.gov NCT00796588Electronic supplementary materialThe online version of this article (doi:10.1186/s13737-016-0033-4) contains supplementary material, which is available to authorized users.

Tourniquet in Plastic Surgery

Tourniquet is invaluable instrument to plastic, hand and orthopedic surgeon. It helps create a bloodless field for easy operation and reduces operative time. The advantages of tourniquet is no without its share of complication including nerve and skin injuries and devastating vascular lesions leading to amputation or death. A thorough understanding of the local and systemic effect of tourniquet is essential to minimize the complication. Various physical and pharmacological modifications reduce the reperfusion injury and also help increase tourniquet time. This review discusses the principle, physiology and complications of tourniquet. Keywords: Tourniquet, Limb occlusion pressure, Reperfusion injury, Nerve palsies, Limb protector sleeves.

Self expandable stent application to prevent limb occlusion in external iliac artery during endovascular aneurysm repair

PurposeIliac extension of stent-graft during endovascular aneurysm repair (EVAR) increases the incidence of limb occlusion (LO). Hypothetically, adjunctive iliac stent (AIS) could offer some additional protection to overcome this anatomic hostility. But still there is no consensus in terms of effective stent characteristics or configuration. We retrospectively reviewed our center's experience to offer a possible answer to this question.MethodsOur study included 30 patients (38 limbs) with AIS placed in the external iliac artery (EIA) from January 2010 to December 2013. We classified iliac tortuosity based on anatomic characteristics. AIS's were deployed in EIA with a minimum 5-mm stick-out configuration from the distal edge of the stent-graft.ResultsAccording to the iliac artery tortuosity index, grade 0, grade 1, and grade 2 were 5 (13.2%), 30 (78.9%), and 3 (7.9%), respectively. The diameter of all AIS was 12 mm, which was as large as or larger than the diameter of the stent-graft distal limb. SMART stents were preferred in 34 limbs (89.5%) and stents with 60-mm length were usually used (89.5%). During a mean follow-up of 9.13 ± 10.78 months, ischemic limb pain, which could be the sign of LO, was not noticed in any patients. There was no fracture, kinking, migration, in-stent restenosis, or occlusion of AIS.ConclusionThe installation of AIS after extension of stent-graft to EIA reduced the risk of LO without any complications. AIS should be considered as a preventive procedure of LO if stent-graft needs to be extended to EIA during EVAR.

0410: Cardiovascular manifestations in antiphospholipid syndrome

Antiphospholipid syndrome (APLS) is defined by the occur-rence thrombosis, and/or obstetric morbidity associated with the presence of antiphospholipid antibodies. Cardiovascular manifestations of APLS are variable and some of them can be life threatening. Retrospective study of patients with APLS (diagnosed according to Sidney classification criteria of 2006) in an Internal medicine department over a period of 14 years. Thirty-four patients with APLS had cardiovascular involvements (66.6%); 30 females and 4 males, with a mean age of 40.5 years (24-74 years). Cardiovascular involvements revealed the disease in 53% of cases. Venous thromboses were most frequent manifestation: deep-vein thrombosis (DVT) (12 cases), pulmonary embolism (5 cases), cerebral venous thrombosis (1 case), inferior vena cava thrombosis (1 case), portal vein thrombosis (1 case), superficial venous thrombosis (1 case) and central retinal vein occlusion (2 cases). Arterial thromboses were noted in 12 patients: stroke (9 cases), upper limb artery, renal artery and occlusion of central retinal artery (each in 1 patient). Acute coronary artery thrombosis was observed in one patient (myocardial infarction). Pericarditis was noted in 3 cases, valvular disease in 2 cases (an aortic and a mitral stenosis), and myocarditis in 1 patient. Anticardiolipin and anti-B2 glycoprotein I antibodies were positive in 47.1% and 52.8% of cases respectively. Anticoagulant therapy was prescribed in thrombotic cases. Pericarditis were treated with corticosteroids and patient with myoarditis had both corticosteroid and immunosuppressant agent. DVP were the most frequent vascular manifestation in patients with APLS. Cardiac involvements are rare but serious. They can affect all parts of the heart but cardiac valvulopathy and coronary artery thrombosis are the most frequent.

Evaluation of the Zenith low-profile abdominal aortic aneurysm stent graft

Low-profile (LP) stent grafts are now commercially available in Europe for endovascular aortic aneurysm repair (EVAR). In this study the midterm outcomes and characteristics of patients treated with this last generation of stent grafts were compared with a cohort of patients treated with "standard-profile" (SP) stent grafts. The current study enrolled all patients treated for elective EVAR by the SP Zenith Flex stent graft (Cook Medical, Bloomington, Ind) between March 2010 and November 2011 and patients treated for elective EVAR by the Zenith LP stent graft (Cook Medical) between November 2011 and March 2013. All patients had a follow-up >18 months. Preoperative computed tomography angiograms were analyzed on a dedicated three-dimensional workstation. All data were prospectively collected in an electronic database and retrospectively analyzed. A comparative study was conducted. The present study included 208 patients (107 SP and 101 LP). Patients' physiologic characteristics were similar in both groups. The iliac anatomy was considered "more challenging" in LP patients: respectively, 7% and 22% (P = .002) of SP and LP patients had bilateral external iliac diameter <7 mm; and 16% and 34% (P = .005) had a combination of an external iliac diameter <7 mm and an iliac tortuosity ratio index >1.5. No 30-day deaths were documented. The 24-month freedom from reintervention and overall survival rates after SP and LP were, respectively, 88% and 91% (P = .450) and 92% and 96% (P = .153). The 24-month rates for freedom from sac expansion and from limb occlusion were 96.4% and 98.7% (P = .320) and 92% and 95% (P = .293), respectively. One patient in each group presented with a type I endoleak during follow-up, and two LP patients presented with a type III endoleak (P = .235). This study demonstrates that the last-generation LP stent grafts have favorable midterm outcomes similar to SP stent grafts despite being used to treat more patients with unfavorable iliac anatomy.

The Effect of Ischemic Preconditioning on Repeated Sprint Cycling Performance.

Ischemic preconditioning enhances exercise performance. We tested the hypothesis that ischemic preconditioning would improve intermittent exercise in the form of a repeated sprint test during cycling ergometry. In a single-blind, crossover study, 14 recreationally active men (mean ± SD age, 22.9 ± 3.7 yr; height, 1.80 ± 0.07 m; and mass, 77.3 ± 9.2 kg) performed twelve 6-s sprints after four 5-min periods of bilateral limb occlusion at 220 mm Hg (ischemic preconditioning) or 20 mm Hg (placebo). Ischemic preconditioning resulted in a 2.4% ± 2.2%, 2.6% ± 2.7%, and 3.7% ± 2.4% substantial increase in peak power for sprints 1, 2, and 3, respectively, relative to placebo, with no further changes between trials observed for any other sprint. Similar findings were observed in the first three sprints for mean power output after ischemic preconditioning (2.8% ± 2.5%, 2.6% ± 2.5%, and 3.4% ± 2.1%, for sprints 1, 2, and 3, respectively), relative to placebo. Fatigue index was not substantially different between trials. At rest, tissue saturation index was not different between the trials. During the ischemic preconditioning/placebo stimulus, there was a -19.7% ± 3.6% decrease in tissue saturation index in the ischemic preconditioning trial, relative to placebo. During exercise, there was a 5.4% ± 4.8% greater maintenance of tissue saturation index in the ischemic preconditioning trial, relative to placebo. There were no substantial differences between trials for blood lactate, electromyography (EMG) median frequency, oxygen uptake, or rating of perceived exertion (RPE) at any time points. Ischemic preconditioning improved peak and mean power output during the early stages of repeated sprint cycling and may be beneficial for sprint sports.

Endovascular Aneurysm Sealing for Infrarenal Abdominal Aortic Aneurysms: 30-Day Outcomes of 105 Patients in a Single Centre

Endovascular aneurysm sealing (EVAS) has been proposed as a novel alternative to endovascular aneurysm repair (EVAR) in patients with infrarenal abdominal aortic aneurysms (AAA). The early clinical experience, technical refinements, and learning curve of EVAS in the treatment of AAA at a single institution are presented. One-hundred and five patients were treated with EVAS between March 2013 and November 2014. Prospective data were recorded on consecutive patients receiving EVAS. Data included demographics, preoperative aneurysm morphology, and 30-day outcomes, including rates of endoleak, limb occlusion, reintervention, and death. Postoperative imaging consisted of duplex ultrasound and computed tomographic angiography. The mean age of the cohort was 76 ± 8 years and 12% were female. Adverse neck morphology was present in 72 (69%) patients, including aneurysm neck length <10 mm (20%), neck diameter >32 mm (18%), β-angulation >60° (21%), and conical aneurysm neck (51%). There was one death within 30 days. The incidence of Type 1 endoleak within 30 days was 4% (n = 4); all were treated successfully with transcatheter embolisation. All four proximal endoleaks were associated with technical issues that resulted in procedure refinement, and all were in patients with adverse proximal aortic necks. The persistent Type 1 endoleak rate at 30 days was 0% and there were no Type 2 or Type 3 endoleaks. Angioplasty and adjunctive stenting were performed for postoperative limb stenosis in three patients (3%). EVAS appears to be associated with reasonable 30-day outcomes despite the necessity of procedural evolution in the early adoption of this technique. EVAS appears to be applicable to patients with challenging aortic morphology and endoleak rates should reduce with procedural experience. The utility of EVAS will be defined by the durability of the device in long-term follow-up, although the absence of Type 2 endoleaks is encouraging.

Correção de aneurisma por via endovascular: fatores de risco para oclusão de ramo

BackgroundLimb occlusion is an important complication of endovascular aneurysm repair (EVAR). We intend to conduct a systematic review of the literature to assess the occurrence and the average time of limb occlusion and identify associated risk factors. Material and methodsA literature search was performed using the query EVAR LIMB OCCLUSION, limited in time to the last ten years, to articles written in Portuguese and English. We selected twenty articles with original data; fourteen from the literature and six from the reference lists of articles read during the selection process. ResultsThe frequency of limb occlusion varies between 0% and 24%. In most studies, the elapsed time to limb occlusion rarely exceeds six months. Age, body mass index, tortuosity of the iliac vessels, stenosis of the iliac or femoral artery>70%, graft type and configuration, limb kinking, anchoring in the external iliac artery (EIA), tertiary hospital, absence of primary stenting during the index procedure and failure to comply to the specific instructions for use were identified as risk factors for limb occlusion. ConclusionsDemographic/co‐morbidities factors seem to have a minor impact in outcome limb occlusion compared to risk factors related to arterial anatomy and related to the surgical technique. The type of graft, the anchoring zone in the EIA and the tortuosity of the iliac vessels seem to be the most important risk factors.

Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans

Venous saline infusions in an arterially occluded forearm evokes reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP). We hypothesized that the application of suction to the human limbs would activate this venous distension reflex and raise sympathetic outflow. We placed airtight pressure tanks and applied 100 mmHg negative pressure to an arterially occluded limb (occlusion and suction, O&S) to induce tissue deformation without fluid translocation. BP, heart rate (HR), and MSNA were assessed in 19 healthy subjects during 2 min of arm or leg O&S. Occlusion without suction served as a control. During a separate visit, saline (5% forearm volume) was infused into veins of the arterially occluded arm (n = 13). The O&S increased limb circumference, MSNA burst rate (arm: Δ6.7 ± 0.7; leg: Δ6.8 ± 0.7 bursts/min), and total activity (arm: Δ199 ± 14; leg: Δ172 ± 22 units/min) and BP (arm: Δ4.3 ± 0.3; leg: Δ9.4 ± 1.4 mmHg) from the baseline. The MSNA and BP responses during arm O&S correlated with those during leg O&S. Occlusion alone had no effect on MSNA and BP. MSNA (r = 0.607) responses during arm O&S correlated with those evoked by the saline infusion into the arm. These correlations suggest that sympathetic activation during limb O&S is likely, at least partially, to be evoked via the venous distension reflex. These data suggest that suction of an occluded limb evokes sympathetic activation and that the limb venous distension reflex exists in arms and legs of normal humans.

Yield of Graft Surveillance after Open Aortic Operations

To examine the value of routine postoperative surveillance duplex in identifying late graft-related complications after open aortic operations for occlusive and aneurysmal disease. All open aortic operations performed at a single institution between 1998 and 2012 were retrospectively reviewed. All patients were scheduled for yearly postoperative surveillance duplex. Patients who had at least 30-day follow-up and at least 1 surveillance duplex were analyzed. Two hundred thirty-eight open aortic operations were performed during the study period, 140 of which met the inclusion criteria. Mean follow-up was 3.9years. A tube graft was performed in 65 (46%), and the proximal anastomosis was in the infrarenal or juxtarenal position in 126 (90%). Overall survival at was 100% and 85.3% at 1 and 5 years, respectively. A mean of three surveillance duplexes was performed per patient. Surveillance duplex scanning identified 31 significant findings in 31 patients, including 13 significant velocity increases (>3:1) and 18 aneurysms/pseudoaneurysms. Thirteen (9%) patients required a graft-related operation at a mean of 3.5years. Indications included anastomotic aneurysm/pseudoaneurysm (n = 7), limb occlusion (n = 3), graft stenosis (n = 2), and graft infection (n = 1). The indication for operation was identified by surveillance duplex in 5 of the 13 cases. The remainder were identified by physical examination and/or clinical presentation. Reintervention-free survival (RIFS) was 98.5% at 1 year and 80.4% at 5 years. On multivariable analysis, RIFS was improved only by the use of a tube graft during the index operation (hazard ratio, 0.73; 95% confidence interval, 0.54-0.96). Routine surveillance duplex identifies few findings that lead to reintervention. Patients with a non-tube-graft reconstruction are at greater risk for reintervention and may benefit from surveillance duplex after open aortic operations.

Sealing zones have a greater influence than iliac anatomy on the occurrence of limb occlusion following endovascular aortic aneurysm repair.

Limb occlusion is a well-known complication following endovascular aortic aneurysm repair (EVAR), and it very often leads to reoperation. The aim of this study is to identify predictive factors for limb occlusion following EVAR. Two hundred and twenty-four patients undergoing EVAR between 2004 and 2012 were included in this retrospective study. Demographics, anatomic, and follow-up data were compared between two groups (with or without thrombosis). Preoperative anatomy was analyzed with a dedicated workstation, using the Society of Vascular Surgery reporting standards. Eleven (4.9%) patients presented with a limb occlusion during follow-up (46 ± 12 months). Univariate analyses were first performed to investigate the influence of preoperative variables on limb occlusion. Then, variables with a p value <0.1 were included in the multivariate analysis and showed that in the occlusion group there was a greater rate of chronic renal failure (18.2% vs. 3.8%, p = 0.012), a more frequent occurrence of distal landing zones in the external iliac artery (15.4% vs. 2.1%, p = 0.006), and a smaller aortic neck diameter (21.0 ± 2.9 mm vs. 23.6 ± 3.3 mm, p = 0.014). Although iliac anatomy does not appear to have a significant influence on limb occlusion rate in the multivariate analysis, proximal and distal sealing zones appear to be involved in this complication.

Performance of the Endurant stent graft in patients with abdominal aortic aneurysms independent of their morphologic suitability for endovascular aneurysm repair based on instructions for use

The aim of this study was to prospectively evaluate the early and late 7-year experience with the Endurant bifurcated stent graft system (Medtronic, Santa Rosa, Calif) in patients with abdominal aortic aneurysms. Between November 14, 2007, and December 2013, 712 consecutive high-risk patients with abdominal aortic aneurysms underwent elective or urgent placement of an Endurant bifurcated endograft in our institution. The included patients were consecutive (all comers) and treated independently from their morphologic eligibility for use of the Endurant device based on the instructions for use. The primary study outcome was freedom from all-cause reintervention. The median follow-up was 19.2 months (interquartile range, 6.3-35.9 months). Overall, 517 patients (72.6%) were treated on the basis of instructions for use conditions. On the other hand, 195 patients (27.4%) had morphologic data not consistent with the recommendations for the use of the Endurant system. The 30-day mortality was 1.4% (10 of 712). Nine patients (1.2%) were lost to follow-up because of relocation abroad. The overall mortality rate was 14.74% (101 of 703). Overall survival rate was 92.3% at 1 year, 86.4% at 2 years, and 65% at 5 years. Overall freedom from reintervention rate was 93.3%, 86.4%, and 65% at 1 year, 2 years, and 5 years, respectively. Five patients (0.7%) underwent a surgical conversion and explantation of the Endurant device. The reasons were endograft infection (n = 1), endoleak type Ia (n = 1), endoleak type II (n = 1), endograft and limb thrombotic occlusion (n = 1), and endotension (n = 1). The overall iliac limb occlusion rate was 2.1% (15 of 712). The performance of the Endurant stent graft during a period of 7 years under real-life conditions was good, with low incidence of reinterventions and endoleaks.