Distal Bypass Research Articles

Omental Flow-Through Flap: Experimental Hemodynamic Study

The omental flow-through flap (OFTF) is based on the use of an anatomic unit composed of the right gastro-omental artery (bypass) with its omental branch or branches supplying the greater omentum (flap). The greater omentum flap is known for its capacity of resistance to infection, for its use in the treatment of ischemic lesions and as a high-flow tissue. Several hypotheses regarding the hemodynamic behavior of a distal bypass with a flap were discussed in the literature. We made the assumption that the OFTF was a low peripheral resistance flap and that the greater omentum did not induce a steal phenomenon. We demonstrated the anatomical feasibility of the experimental model with a morphologic study inthe pig. The mail objective of this study was to measure the blood flow to evaluate the hemodynamic effects of the OFTF. Twelve domestic pigs were used for this study. Four cadavers of pigs were dissected for the anatomic study of the OFTF, and 8 live pigs were used for the experimental surgery and hemodynamic measurements. Hemodynamic measurements were taken before transplantation on in situ arteries using periarterial ultrasonic flow transducers. After transplantation of the OFTF, flows were measured before, then during clamping and unclamping of the flap. OFTF was feasible in the porcine model. With the experimental model, the flow increased by 56.15% in the distal part of the bypass after the implantation of the flap with decrease of peripheral resistances. Our results suggest that the OFTF is a low resistance flap and that the greater omentum does not induce a steal phenomenon. This anatomic unit could be used to carry out simultaneously limb revascularization and cover a tissue loss.

IP231. Predictors of Adequate Size Greater Saphenous Vein for Use in Distal Lower Extremity Arterial Bypasses

IP231. Predictors of Adequate Size Greater Saphenous Vein for Use in Distal Lower Extremity Arterial Bypasses

New simple image overlay system using a tablet PC for pinpoint identification of the appropriate site for anastomosis in peripheral arterial reconstruction.

To evaluate the accuracy and utility of a new image overlay system using a tablet PC for patients undergoing peripheral arterial reconstruction. Eleven limbs treated with distal bypass surgery were studied. Three-dimensional images obtained by processing a preoperative contrast-enhanced computed tomography scan were superimposed onto the back-camera images of a tablet PC. We used this system to pinpoint a planned distal anastomotic site preoperatively and to make a precise incision directly above it during surgery. We used a branch artery near the distal anastomotic site as a reference point and the accuracy of the system was validated by comparing its results with the intraoperative findings. The precision of the system was also compared with that of a preoperative ultrasonographic examination. Both the image overlay system and ultrasonography (US) accurately identified the target branch artery in all except one limb. In that limb, which had a very small reference branch artery, preoperative US wrongly identified another branch, whereas the image overlay system located the target branch with an error of 10mm. Our image overlay system was easy to use and allowed us to precisely identify a target artery preoperatively. Therefore, this system could be helpful for pinpointing the most accurate incision site during surgery.

Intercondylar Route of Prosthetic Infragenicular Femoropopliteal Bypass Has Better Primary, Assisted, and Secondary Patency but Not Limb Salvage Rate Compared to the Medial Route.

Aim. To compare the differences between medial and intercondylar infragenicular femoropopliteal prosthetic bypasses in terms of their midterm patency and limb salvage rates. Methods. Ninety-three consecutive patients with peripheral arterial disease who underwent a simple distal femoropopliteal bypass using a reinforced polytetrafluorethylene graft were included in this retrospective study. The bypass was constructed in the intercondylar route in 52 of the patients (group A) and in 41 in the medial route (group B). Results. Median observation time of the patients was 12.7 (IQR 4.6–18.5) months. There were 22 and 24 interventional or surgical procedures (angioplasty, stenting, thrombolysis, thrombectomy, or correction of the anastomosis) performed to restore patency of the reconstruction in groups A and B, respectively (p = 0.14). The 20-month primary, assisted, and secondary patency rates and limb salvage rates were 57%, 57%, 81%, and 80% in group A compared to 21%, 23%, 55%, and 82% in group B (p = 0.0012, 0.0052, 0.022, and 0.44, resp.). Conclusion. Despite better primary, assisted, and secondary patency rates in patients with a prosthetic infragenicular femoropopliteal bypass embedded in the intercondylar fossa compared to patients with the medial approach, there is no benefit in terms of the limb salvage rate and the number of interventions required to maintain patency of the reconstruction.

Preserved Renal Function in Kidney Transplantation over a Thrombosed Aortobifemoral Bypass Graft: The Role of Retrograde Flow and Early Thrombolysis.

Aortobifemoral bypass (ABFB) thrombosis is not uncommon, and when the artery of a renal graft is implanted on a bypass the risk of graft loss is high. We report the case of a 48-year-old woman with a previous history of ABFB under antiplatelet therapy and a kidney allograft implanted on the vascular prosthesis, who presented with acute limb ischemia and severe renal impairment. Imaging techniques revealed a complete thrombosis of the proximal left arm of the ABFB. However, a faint retrograde flow over the graft was observed thanks to the recanalization of distal left bypass by collateral native arteries. This unusual situation not previously reported in a kidney transplant setting, together with an early diagnosis, allowed graft survival until an early local thrombolysis resolved the problem. Two years later, renal function remains normal.

Wound Healing Society 2014 update on guidelines for arterial ulcers.

Wound Healing Society 2014 update on guidelines for arterial ulcers.

Microvascular Reconstruction in the Revascularised Diabetic Foot: A Perforosome Approach

Microvascular Reconstruction in the Revascularised Diabetic Foot: A Perforosome Approach

Abstract 18723: In vivo Tissue Engineered Small Diamiter Vascular Graft “Biotube”; Application to Off-pump CABG in the Porcine Model

Objective: In spite of the great labor and fund for the development of the small diameter vascular prostheses applicable to the coronary arterial bypass grafting (CABG), the only available grafts are still autologous arteries and veins. Aiming for the application to CABG and below knee distal arterial bypass grafting, we have developed autologous small diameter grafts (ID; 1.5 ~ 5 mm) “Biotubes” constructed in the recipient bodies. In AHA 2006, we have already reported that "BIOTUBEs" could be ideal small-caliber vascular grafts in rabbit model. In this study, we evaluate the feasibility of Biotubes to the off-pump CABG using an acute xenogeneic porcine model. Materials & Methods: Silicon rod molds (diameter; 3 mm, length; 15 cm) were embedded in the subcutaneous pouches of beagle dogs for 4 weeks to obtain Biotubes. They were xenogenically implanted to swine using conventional off-pump CABG technique (n=5). Top-end anastomosis of each Biotube was placed on innominate artery using 8-0 polypropylene sutures. Its distal end was anastomosed to the side of left anterior descending coronary artery (LAD) with 8-0 sutures using cardiac stabilizer. Results: The obtained Biotubes had very thin wall (less than 0.1 mm) mainly consisting of fibroblasts and collagen fibers as previously reported. However, anastomoses of Biotubes to native arteries were possible even under off-pump surgery with a little difficulty. Postoperative angiography and doppler flow meter confirmed their patency and durability without rupturing or aneurysm formation. Conclusion: Application of Biotubes to the off-pump CABG was technically feasible in an acute swine model. Long-term animal CABG implantation study using auto-grafts is planed in the next stage for clinical use.

Contemporary Outcomes for Open Infrainguinal Bypass in the Endovascular Era

The role of infrainguinal bypasses in this era of increasing endovascular interventions remains the subject of significant debate. In this study, we evaluate contemporary long-term outcomes of lower-extremity open revascularization for peripheral arterial disease (PAD). We evaluated all patients who underwent infrainguinal bypass with autogenous vein conduits for claudication or critical limb ischemia in our institution between January 1st, 2007 and July 31st, 2014. Kaplan-Meier and Cox regression analyses were used to evaluate graft failure and identify its predictors. Outcomes were defined per the Society for Vascular Surgery standards. There were 428 autogenous vein grafts (femoro-popliteal: 32%, femoro-tibial: 39%, popliteo-tibial: 27%, and tibio-tibial: 2%) placed in 368 patients (mean age of 67 ± 11.4 years). Most patients were male (59%), white (73%), and presented with critical limb ischemia (81%). Sixty-five cases (15%) were redo bypasses. Arm veins and spliced vein conduits were used in 15% and 14% of cases, respectively. Primary patency at 1, 3, and 5 years was 66%, 59%, and 55%, respectively. Primary-assisted patency was 78%, 69%, and 64% at 1, 3, and 5 years, respectively. Secondary patency was 88%, 84%, and 82% at 1, 3, and 5 years, respectively. Patency was higher for grafts harvested from the lower versus upper extremities and for proximal versus distal bypass (all P < 0.05). Limb salvage rate was 88% after a mean follow-up of 2 ± 1.8 years. Significant predictors of graft failure were younger age, diabetes mellitus, and hyperlipidemia (all P < 0.05). In this contemporary cohort of patients, we have demonstrated that infrainguinal bypass for lower-extremity revascularization has good long-term outcomes in patients with symptomatic PAD. Patency and limb salvage rates are optimized with careful selection of autogenous conduits, close monitoring of high-risk groups and management of comorbidities.

全身性エリテマトーデスに抗リン脂質抗体症候群を合併して発症した虚血壊死に対して，distal bypass 術を施行し治癒に至った1 例

全身性エリテマトーデスに抗リン脂質抗体症候群を合併して発症した虚血壊死に対して，distal bypass 術を施行し治癒に至った1 例

Favorable outcomes of very elderly patients with critical limb ischemia who undergo distal bypass surgery

To determine the midterm outcomes of distal bypass surgery for very elderly patients, and to determine the ideal candidates for this procedure. Of 268 consecutive patients (328 limbs) with critical limb ischemia who were treated between 2006 and 2013, 106 (126 limbs) underwent distal bypass and were retrospectively reviewed. Nineteen patients (22 limbs) were aged ≥80 years (very elderly group) and 87 patients (104 limbs) were aged <80 years (control group). The baseline characteristics differed between the 2 groups in terms of regular hemodialysis rate (very elderly group, 4 [21%] vs control group, 60 [69%]; P = .0002) and the Charlson comorbidity index (very elderly group, 3.2 ± 1.7 vs control group, 5.0 ± 2.0; P = .0005). According to the Rutherford category of limb ischemia (4/5/6), the very elderly and control groups were classified as 5/17/0 and 11/87/6, respectively (P = .18). Before the surgery, 17 patients (77%) and 67 patients (64%) were ambulatory in the very elderly and control groups, respectively. At follow-up at 29 ± 22 months, the rates of primary (P = .33) and secondary patency (P = .14), limb salvage (P = .50), survival (P = .26), amputation-free survival (P = .42), major adverse limb event and also perioperative death (P = .11), and major adverse cardiovascular events (P = .36) did not significantly differ between the groups. In multivariate analysis, a history of coronary artery disease (hazard ratio [HR], 2.7; 95% confidence interval [CI], 1.3-5.9; P = .005), preoperative nonambulatory status (HR, 4.2; 95% CI, 2.1-8.1; P < .0001), and serum albumin levels <3 g/dL (HR, 2.7; 95% CI, 1.3-5.4; P = .01) were significantly related to poor amputation-free survival. Thirteen patients (59%) remained ambulatory at the latest follow-up. In 91 patients (110 limbs) with tissue loss, the Society for Vascular Surgery lower extremity threatened limb classification system: risk stratification based on Wound, Ischemia, and foot Infection classification stages 3 and 4 negatively affected complete wound healing, according to multivariate analysis (HR, 0.34; 95% CI, 0.20-0.61; P = .0005). A very elderly age should not preclude a patient from undergoing distal bypass surgery. A history of coronary artery disease, a nonambulatory status, and hypoalbuminemia, along with the Wound, Ischemia, and foot Infection classification for patients with tissue loss, should be carefully considered to obtain the most benefit from distal bypass surgery.

The efficacy of salvage interventions on threatened distal bypass grafts

Infrapopliteal bypass is an established and effective method for limb salvage in patients with critical limb ischemia. Secondary interventions maybe required to maintain graft patency. The aim of this study was to look at the frequency and outcomes of such interventions. Consecutive patients undergoing bypasses onto the infrapopliteal vessels for critical limb ischemia (Rutherford 4-6) at a single institution were analyzed between 2009 and 2013. The primary end points were graft patency, amputation-free survival (AFS), and freedom from reintervention at 12 months by Kaplan-Meier analysis. A total of 114 infrapopliteal bypasses were performed in 102 patients. Distal anastomosis was on to the anterior tibial (n = 31), posterior tibial (n = 27), peroneal (n = 24), tibioperoneal trunk (n = 23), or dorsalis pedis artery (n = 9). Primary patency, assisted primary patency, and secondary patency was 57%, 76%, and 82%, respectively, at 12 months and 44%, 70%, and 80%, respectively, at 36 months. AFS was 80% at 12 months and 65% at 36 months. Endovascular salvage interventions were performed on 58 grafts (51%) including angioplasty of inflow/proximal anastomosis (33%), outflow/distal anastomosis (46%), and graft stenosis (20%), with a further 12 grafts (11%) undergoing thrombolysis for occlusion. Surgical salvage interventions included jump grafts (n = 7), revision of anastomotic stenosis (n = 3), and thrombectomy (n = 2). AFS was similar in salvaged threatened and acutely occluded grafts compared with nonthreatened grafts (P = .064) and better in grafts requiring reintervention later (>6 months from bypass) compared with those requiring early reintervention (<6 months; P = .047). Secondary interventions in threatened distal bypass grafts are successful at maintaining graft patency and AFS when compared with nonthreatened grafts, and are associated with a low morbidity rate.

A102 - Proximal Versus Distal Gastric Bypass In Patients With Body Mass Index 50 to 60: A Double-Blind, Randomized Clinical Trial

A102 - Proximal Versus Distal Gastric Bypass In Patients With Body Mass Index 50 to 60: A Double-Blind, Randomized Clinical Trial

Inflow Can Be Enough: A Limited Approach to Revascularization in Critical Limb Ischemia

Objectives: Traditionally, in-line vascular reconstruction is held as the gold standard for the treatment of critical limb ischemia (CLI). However, there is a paucity of data regarding treatment of inflow alone to resolve rest pain or heal tissue loss. Thepurposeof this studywas todetermine theoutcomesofpatients with CLI who underwent an inflow-only approach to revascularization as their initial treatment of CLI. Methods: All patients undergoing femoral endarterectomy with or without endovascular treatment were reviewed. Patients were included for analysis if they had CLI defined by rest pain or tissue loss and did not present acutely. Exclusion criteria were prior vascular surgical interventions, concomitant distal bypass, and claudication as an indication. Preoperative imaging was reviewed and a runoff score for the whole leg, as well as above-knee and below-knee scores were calculated using the modified Bollinger runoff score. Results: A total of 247 in-flow procedures were identified over a 5-year period, and 65 met criteria. Mean age was 72.4 years; 57% had tissue loss. The average followup was 18 (standard deviation [SD], 17.3) months (range, 0-68 months). There was one 30-day mortality (1.5%).

Impact of infrapopliteal endovascular treatment on the outcome of subsequent ipsilateral distal bypass for critical limb ischemia.

We retrospectively reviewed the outcomes of distal bypass for critical limb ischemia and investigated the impact on outcomes of prior unsuccessful ipsilateral infrapopliteal endovascular treatment (EVT). Between January 2005 and December 2014, we performed 142 infrainguinal bypasses for critical limb ischemia with ischemic gangrene (Rutherford classes V or VI), including 80 distal bypasses in 74 patients (male 54, female 20, median age 68.4 years, range 51-81 years). All distal bypasses used an autologous saphenous vein graft. Surgical outcomes were compared between 37 distal bypasses without prior infrapopliteal EVT (NEVT group) and 43 distal bypasses after unsuccessful infrapopliteal EVT (PEVT group). Infrapopliteal EVT was performed with balloon dilatation without stenting in all cases. There were no significant differences in preoperative conditions or risk factors between the NEVT and PEVT groups, except for the era of bypass surgery and dependence on hemodialysis. The 3-year primary and secondary patencies were 69% and 72% in the NEVT group and 78% and 80% in the PEVT group (P=0.86, P=0.79). The 3-year limb salvage rates were 81% in the NEVT group and 82% in the PEVT group (P=0.52), and the 3-year amputation-free survival rates were 56% and 57% in the respective groups (P=0.32). Standard errors of the mean for all Kaplan-Meier curves were <10% within 3 years follow-up. The clinical outcomes of distal bypass without prior infrapopliteal EVT were not superior to those of distal bypass after unsuccessful ipsilateral infrapopliteal EVT. Therefore, unsuccessful infrapopliteal EVT does not have a negative impact on the outcome of subsequent ipsilateral distal bypass in patients with critical limb ischemia.

Occluded Superficial Femoral and Popliteal Artery Stents Can Have a Negative Impact on Bypass Target

Purpose: To identify whether occluded femoropopliteal stents influence previously available lower extremity bypass (LEB) targets. Methods: Among 621 consecutive patients who had undergone stenting of a superficial femoral artery or popliteal artery lesion from January 2009 to December 2013, 30 patients (mean age 69.9±10.2 years; 16 women) were found to have occluded stents. Angiograms before stent placement were analyzed to determine what would have been the optimal distal bypass site, which was compared with the angiogram following stent occlusion. Results: Seven (22%) limbs lost the bypass target. In one limb, the target changed from above-knee to below-knee popliteal, in 2 limbs from above-knee popliteal to tibial, and in 4 limbs from below-knee popliteal to tibial artery. Eleven (34%) limbs required LEB during follow-up. Chronic obstructive pulmonary disease (p=0.007), chronic renal insufficiency (p=0.026), a popliteal artery stent (p=0.001), and the below-knee popliteal artery as an optimal bypass target (p=0.026) were associated with loss of bypass target following stent occlusion. Conclusion: Superficial femoral artery and popliteal artery stent occlusion can affect target vessels in patients who may require subsequent LEB. This should be considered when performing stenting.

Midterm Outcomes of Salvage Angioplasty on Threatened Distal Bypass Grafts

Midterm Outcomes of Salvage Angioplasty on Threatened Distal Bypass Grafts

Heparin-Bonded Polytetrafluorethylene Does Not Improve Hemodialysis Arteriovenous Graft Function

Heparin-bonded polytetrafluorethylene (hep PTFE), when compared with standard PTFE, has been shown to have a modest improvement in distal extremity bypass grafts. The data supporting its usage for dialysis access are less clear. We compared the patency rates, number of interventions, and complications between hep PTFE grafts and nonheparin-bonded PTFE (nonhep PTFE) grafts placed for dialysis access. A retrospective review of all dialysis access procedures between January 2013 and March 2014 entered into a prospectively maintained vascular surgery database was performed. Our primary end point was functional graft patency. Secondary end points were primary, primary assisted, and secondary patency, as well as time to graft abandonment, and number of procedures required to maintain or restore graft patency. The number of interventions required to maintain graft patency and graft-related complications were also reviewed. Kaplan-Meier curves were used to compare the 2 groups. Between January 2013 and March 2014, 301-dialysis access procedures were performed, which included 70 arteriovenous grafts (AVGs) comprised 32 hep PTFE (32, 6-mm straight grafts) and 38 nonhep PTFE (35, 4-7-mm taper and 3, 6-mm straight). Mean follow-up was 7.35 ± 5.15 months. At 1 year, Kaplan-Meier survival curves showed that functional patency between hep PTFE and nonhep PTFE AVG were 60% and 75%, respectively (P = 0.37). Primary and secondary patencies were not significantly different between groups; however, primary-assisted patency was significantly improved at 1 year (hep PTFE versus nonhep PTFE: 50% vs. 80%; P = 0.02). The number of hep PTFE grafts undergoing percutaneous thrombectomy was significantly higher than the nonhep PTFE grafts (11 vs. 2; P = 0.009). The incidence and time to graft abandonment were not statistically different. The same was true for the number of complications between the 2 groups. Multivariate analysis showed nonhep PTFE AVG to be advantageous for primary and primary-assisted patency. We did not demonstrate a benefit to the routine use of hep PTFE for AVG creation especially given the higher cost of these grafts. Functional patency rates were not improved, and the rates of reintervention and thrombectomy were higher with hep PTFE AVGs.

Distal small bowel bypass for weight regain after gastric bypass: safety and efficacy threshold occurs at

BackgroundFor patients with poor weight loss (WL) after Roux-en-Y gastric bypass (RYGB) there are few well-tolerated and effective surgical options. Revision to distal bypass by shortening of the common channel (CC) induces significant WL but often produces protein calorie malnutrition (PCM) and severe diarrhea. ObjectiveThe aim of this study was to identify a safe and effective threshold for distal small bowel bypass when done for revision of gastric bypass. SettingAcademic Institution, United States. MethodsWe performed revision of RYGB for WL in 20 patients by shortening the CC to a new length of 120–300 cm. The Roux limb length was unchanged. WL and PCM were monitored. A threshold for percent of small bowel bypassed at which PCM was avoided was retrospectively determined. WL was then compared in patients above and below this threshold. Five patients completed a 250-kcal mixed meal challenge before and 3 months after revision to determine selected gut hormone responses. ResultsBypassing≥70% small bowel resulted in PCM in 4 of 10 patients but in none of 10 patients below that threshold. PCM was observed as late as 2 years after revision and necessitated rerevision by lengthening of the CC in 3 patients. Additionally, nocturnal diarrhea was more common and more intractable when≥70% bypass was done. Both groups had significant excess body WL over 2 years, but it was greater in patients with≥70% bypass (47±19 versus 26±17; P<.05). A favorable gut hormone response was observed with 3-hour decrease in glucose-dependent insulinotropic peptide (GIP) by 25% and increase in glucagon-like peptide-1 (GLP-1) by 25%, whereas fasting peptide-YY (PYY) increased by 71% (P<.05 for all). ConclusionsRevision of RYGB to distal bypass when it is<70% of a patient’s small bowel length results in an acceptable balance of WL and a positive safety profile. WL may be mediated through an enhanced gut hormone effect, an aversion to ingested fat, and possibly other mechanisms.

Distal bypass と圧迫療法の併用が有効であった下腿混合性潰瘍の 1 症例

Distal bypass と圧迫療法の併用が有効であった下腿混合性潰瘍の 1 症例