Using Isolated Femoral Bifurcation Endarterectomy or Combined with Bypass Surgery for Patients with Chronic Limb-Threatening Ischemia

Background and Objectives: The aim of this study was to evaluate the clinical outcomes of patients suffering from chronic limb-threatening ischemia (CLTI) and tissue loss treated with primary isolated femoral bifurcation endarterectomy (FBE) or with FBE combined with bypass surgery. Materials and Methods: This retrospective study was performed in a tertiary university-based care centre. Between January 2008 and December 2019, a prospectively collected database of patients suffering from CLTI and tissue loss and undergoing either primary FBE (group A) or FBE in combination with bypass surgery (group B) was analysed. Study endpoints were ulcer healing, primary and secondary patency rate, limb salvage, and survival. Results: In total, FBE was performed in 73 patients and FBE with bypass in 60 patients. Between both groups, there were no significant differences regarding demographic data or the Global Limb Anatomic Staging System (GLASS) grade III and IV of femoropopliteal lesions. After 3 years, ulcer healing could be achieved in 72% of FBE and in 75% of FBE with bypass patients. The primary patency rate was 95% and 91% for FBE and 83% and 80% for FBE with bypass after one and three years, respectively. The 3-year limb-salvage rate was 78% for FBE and 84% for FBE with bypass. The secondary patency rate after one and three years was 99% and 97% for FBE and 93% and 88% for FBE with bypass. Conclusions: FBE and FBE with bypass are equally effective for ulcer healing in cases of combined CFA and superficial femoral artery lesions. There was no significant difference between both groups regarding primary and secondary patency rates, limb salvage rates and ulcer healing. Isolated FBE could be an alternative strategy in patients with higher operative risk.

Vein Bypass Versus Nitinol Stent in Long Femoropopliteal Lesions: 4-Year Results of a Randomized Controlled Trial

OBJECTIVES

The aim of this study was to compare technical success, patency rates and clinical outcomes of vein bypass (VBP) with angioplasty and nitinol stents (NS) in femoropopliteal Trans-Atlantic Intersociety Consensus (TASC) II C and D lesions.

SUMMARY BACKGROUND DATA

Guidelines widely recommend an endovas-cular-first strategy for long femoropopliteal lesions without sufficient data comparing it with vein bypass surgery.

METHODS

A single-center prospective, randomized controlled trial (RCT) was performed, after approval of the local ethics committee, with technical success, primary and secondary patency as primary endpoints. Secondary endpoints were limb salvage, survival, complications, and clinical improvement.

RESULTS

Between 2016 and 2020, 218 limbs (109 per group) in 209 patients were included. Baseline and lesion characteristics were similar in both groups with a mean lesion length of 268 mm. The indication for treatment was chronic limb threatening ischemia in 53% of limbs in both groups. Technical success was feasible in 88% in the stent group. During a 4-year follow-up, primary patency, freedom from target lesion revascularizations, limb salvage, survival and complications showed no significant differences between the groups. At 48 months secondary patency for the bypass group was 73% versus 50% in the stent group ( P = 0.021). Clinical improvement was significantly superior in the bypass group with 52% versus 19% reaching a Rutherford 0 category ( P < 0.001).

CONCLUSIONS

This is the largest RCT comparing angioplasty with NS and vein bypass in femoropopliteal TASC II C and D lesions and the first to report 4-year results. The data underline the feasibility of endovascular treatment in long lesions but also emphasize the advantages of VBP.

Revascularization Strategies for Patients With Femoropopliteal Peripheral Artery Disease

BACKGROUND

No adequately powered studies exist to compare major clinical outcomes after endovascular therapy (EVT) with stent implantation vs bypass surgery (BSx) for symptomatic femoropopliteal peripheral artery disease.

OBJECTIVES

This study sought to perform a pooled analysis of individual patient data from all randomized controlled trials comparing EVT vs BSx.

METHODS

Principal investigators of 5 of 6 available randomized controlled trials agreed to pool individual patient data. The primary endpoint was major adverse limb events, a composite of all-cause death, major amputation, or target limb reintervention. Secondary endpoints included amputation-free survival, individual major adverse limb event components, and primary patency. Early complications were bleeding, infection, or all-cause death within 30 days.

RESULTS

A total of 639 patients were analyzed with a mean age of 68.1 ± 9.1 years and 29.0% women. Baseline characteristics were comparable between groups. At 2 years, there were no significant differences between patients who received EVT and those who received BSx regarding major adverse limb events (40.1% vs 36.4%; log-rank P = 0.447; adjusted HR [aHR]: 1.04; 95% CI: 0.80-1.36), amputation-free survival (88.1% vs 90.0%; log-rank P = 0.455; aHR for death or amputation: 1.04; 95% CI: 0.63-1.71) and the other secondary endpoints except for primary patency, which was lower in patients who received EVT vs those who received BSx (51.2% vs 61.3%; log-rank P = 0.024; aHR for loss of primary patency: 1.31; 95% CI: 1.02-1.69). EVT was associated with significantly lower rates of early complications (6.8% vs 22.6%; P < 0.001) and shorter hospital stay (3.1 ± 4.2 days vs 7.4 ± 4.9 days; P < 0.001).

CONCLUSIONS

These findings further support the efficacy and safety of EVT as an alternative to BSx in patients with symptomatic femoropopliteal peripheral artery disease.

Long-Term Results of Endovascular Treatment with Nitinol Stents for Femoropopliteal TASC II C and D Lesions

Background and Objectives: The feasibility of endovascular treatment (EVT) for Trans-Atlantic Inter-Society Consensus (TASC) II C and D femoropopliteal artery lesions has been described, but no prospective study has performed a long-term follow-up. The aim of this study was to report the long-term results of nitinol stents (NS) for the treatment of long femoropopliteal lesions. Materials and Methods: A single-center prospective, randomized controlled trial (RCT) comparing EVT with NS and vein bypass surgery was previously performed. The EVT group’s follow-up was extended and separately analyzed with primary patency as the primary endpoint. The secondary endpoints were technical success, secondary patency, reinterventions, limb salvage, survival, complications, and clinical improvement. Results: Between 2016 and 2020, 109 limbs in 103 patients were included. A total of 48 TASC II C and 61 TASC II D lesions with a mean lesion length of 264 mm were reported. In 53% of limbs, the indication for treatment was chronic limb-threatening ischemia. The median follow-up was 45 months. Technical success was achieved in 88% of cases, despite 23% of the lesions being longer than 30 cm (retrograde popliteal access in 22%). At four-year follow-up, primary patency, secondary patency, and freedom from target lesion revascularizations were 35%, 48%, and 58%, respectively. Limb salvage and survival were 90% and 80% at 4 years. Clinical improvement of at least one Rutherford category at the end of follow-up was achieved in 83% of limbs. Conclusions: This study reports the longest follow-up of endovascular treatment with nitinol stents in femoropopliteal TASC II C and D lesions. The results emphasize the feasibility of an endovascular-first strategy, even in lesions beyond 30 cm in length, and clarify its acceptable long-term durability and good clinical outcomes. Large multicenter RCTs with mid- and long-term follow-up are needed to investigate the role of different endovascular techniques in long femoropopliteal lesions.

Preoperative anxiety as predictor of perioperative clinical events following carotid surgery: a prospective observational study

BACKGROUND

Psychological factors like anxiety and depression are recognised to play a causal role in the development of cardiovascular disease and they may also influence outcome after vascular surgery procedures. The aim of this study was to investigate the association of anxiety and depression with postoperative outcome following elective carotid surgery.

METHODS

Single centre prospective observational study of patients treated for asymptomatic carotid artery stenosis at an academic vascular surgery centre. Preoperative anxiety and depression were evaluated using self-reporting questionnaires: Spielberger State-Trait Anxiety Inventory (STAI-S/-T) and Hospital Anxiety and Depression Scale (HADS-A/-D). Postoperative morbidity and mortality were assessed with the primary composite endpoint of stroke, myocardial infarction (MI) and death. Standard reporting guidelines for carotid disease were applied.

RESULTS

From June 2012 to November 2015, 393 carotid endarterectomies (CEA) were performed at our institution. Out of those, 98 asymptomatic patients were available for analysis (78% male; median age, 71.1 years). Median scores of self-reporting questionnaires did not differ from published data of the general population (STAI-T, trait component, median, 36; IQR, 31-42.75; STAI-S, state component, median, 38; IQR, 32-43; HADS-A median, 6; IQR, 3-8; HADS-D median, 4; IQR, 2-7). Cardiovascular risk factors were similar in anxious and non-anxious patients. The composite endpoint of stroke, MI and death occurred significantly more often in patients presenting with a preoperative HADS-A score higher than 6 (10.5%, 95% CI, 3-25; p =.020).

CONCLUSIONS

The present study indicates that preoperative anxiety is associated with the occurrence of intra- and postoperative neurological events in patients undergoing CEA. Patients who had a preoperative HADS-A score of 6 or less had a very low probability of experiencing these complications.

Comparison of Prosthetic and Vein Bypass with Nitinol Stents in Long Femoropopliteal Lesions

BACKGROUND

Guidelines for the treatment of long femoropopliteal lesions are not based on a high level of evidence and recent randomized controlled trials (RCTs) challenge vein bypass (VBP) as the recommended therapy. This study compared prosthetic (PTFE) bypass, VBP and angioplasty with nitinol stents in long femoropopliteal lesions.

METHODS

Pooled data from a RCT and a retrospective database with the same inclusion criteria were analyzed with primary and secondary patency as well as freedom from target lesion revascularization (TLR) as primary endpoints.

RESULTS

Between 2016 and 2018 a total of 172 lesions were treated in three groups (PTFE: n = 62, VBP: n = 55, stent: n = 55). Clinical and lesion characteristics were similar with mean lesion lengths between 260 and 279mm. Technical success rate in the stent group was 87%. There were no significant differences between the groups in patency rates, freedom from TLR, limb salvage and survival during 2-year follow-up. The primary patency rates for the PTFE, VBP and stent groups were 50%, 56% and 60% at 2 years. The PTFE group had significantly less complications compared to the other groups and a shorter hospital-stay compared to the VBP group. Clinical improvement was significantly better in the PTFE and VBP group compared to the stent group.

CONCLUSIONS

The 2-year results indicate that the role of VBP as the recommended therapy for long femoropopliteal lesions may not be unchallenged due to the similar results in all three groups. Further RCTs are needed to determine the best revascularization modality for long femoropopliteal lesions.

Nitinol Stent Versus Bypass in Long Femoropopliteal Lesions: 2-Year Results of a Randomized Controlled Trial

OBJECTIVES

This study sought to compare patency rates and clinical outcomes of nitinol stents and primary vein bypass in long femoropopliteal lesions.

BACKGROUND

An endovascular-first strategy for long femoropopliteal lesions is widely recommended without sufficient data comparing it with bypass surgery. Nitinol stents are widely used as the standard endovascular therapy.

METHODS

A single-center randomized controlled trial was performed with the primary endpoints of technical success, primary and secondary patency. Secondary endpoints were limb salvage, survival, complications, and clinical improvement.

RESULTS

A total of 110 limbs (55 per group) in 103 patients were treated. Baseline and lesion characteristics were similar, with a mean lesion length of 276 mm. Critical limb threatening ischemia was the indication for treatment in 49% of limbs in both groups. Technical success was achieved in 87% in the stent group. During a 2-year follow-up, patency rates, limb salvage, survival and complications showed no significant differences between both groups. At 24 months, primary and secondary patency rates for the stent group were 60% and 72% versus 56% and 73% in the bypass group, respectively. Clinical improvement was significantly better in the bypass group.

CONCLUSIONS

There were no significant differences regarding patency rates, limb salvage, survival, or complications after 2 years. Technical success and clinical improvement in the bypass group were significantly better, but the promising results of the stent group suggest that an endovascular-first strategy for femoropopliteal lesions up to 30 cm may be reasonable. Mid- as well as long-term results need to be awaited.

Small Saphenous Vein and Arm Vein as Bypass Grafts for Upper Extremity Ischemia

BACKGROUND

Bypass in the upper extremity is a rare procedure mainly performed for chronic ischemia, trauma, or hemodialysis access complications. Feasibility and success of use of the arm vein and small saphenous vein (SSV) for autologous vein bypass have been reported in peripheral artery bypass procedures. There are very few reports on the use of alternative veins in upper extremity bypass. We report our experience with arm vein and SSV as a graft source in upper extremity arterial disease.

METHODS

Retrospective analysis of a consecutively collected case series in an academic tertiary referral center from January 2010 to February 2018. Study end points were primary patency, secondary patency, limb salvage, and survival.

RESULTS

In total, 47 patients were treated with upper extremity bypass either using the SSV (n = 17) or arm veins (n = 30). Indications were either acute (n = 12) or chronic ischemia (n = 35) caused by acute (n = 8) and chronic (n = 9) trauma, sequela of iatrogenic interventions (n = 4), peripheral artery disease (n = 14), thrombangiitis obliterans (n = 3), and dialysis-access-related complications (n = 9). An arm vein was used in 30 and the SSV in 17 patients. Primary patency after 12 months was 87% with the SSV and 75% with an arm vein (P = 0.8) and 63% and 75% after 36 months (P = 0.9). Secondary patency were 100% with an arm vein and 100% with the SSV after 36 months (P = 0.4). One patient had to undergo major amputation and 2 minor amputations.

CONCLUSIONS

Arm vein revascularization using the primarily arm vein or SSV as a bypass conduit can be performed with reasonable mortality and morbidity rates and provide good results comparable with the greater saphenous vein.

Paclitaxel-coated versus plain balloon angioplasty in the treatment of infrainguinal vein bypass stenosis

OBJECTIVE

The aim of this study was to compare the clinical and hemodynamic outcomes of plain vs paclitaxel-coated percutaneous transluminal angioplasty (PTA) in patients with infrainguinal vein bypass stenosis.

METHODS

A single-center retrospective analysis was conducted of consecutive patients treated by infrainguinal bypass PTA. Primary study end points were primary and assisted primary patency. Secondary end points were clinical and hemodynamic improvement, limb salvage, and survival. Society for Vascular Surgery reporting standards were applied.

RESULTS

From April 2008 to November 2014, 83 infrainguinal vein bypasses were treated for graft stenosis by plain (group A, n = 41) or by paclitaxel-coated PTA (group B, n = 42). The groups did not differ significantly in mean age (71.9 years for both groups; P = .99), hypertension (P = 1.0), hyperlipidemia (P = .5), diabetes (P = .6), coronary artery disease (P = 1.0), smoking (P = 1.0), preoperative ankle-brachial index (P = .08), or bypass characteristics (below-knee, P = .82). Technical success rate was 100% for both groups. Mean follow-up was 2.9 years for group A patients and 2.2 years for group B patients (P = .08). No patient was lost to follow-up. Primary patency rates were 88% vs 87% and 73% vs 75% (P = .19) and assisted primary patency rates were 88% vs 90% and 77% vs 84% (P = .76) for group A and B patients at 1 and 2 years, respectively. Repeat target lesion revascularization rates were 22% vs 14% (P = .17). At the last follow-up, there were eight vs seven bypass occlusions (P = .74) for group A and B patients, respectively. In univariate analysis, proximal in-graft stenosis (Cox F, P = .041), bypass failure <6 months after bypass surgery (Cox F, P = .013), more than one bypass stenosis per graft (Cox F, P = .047), and redo bypass procedure (Cox F, P = .0001) were significantly related to assisted primary bypass patency. Immediate hemodynamic and sustained clinical improvement rates were 88% vs 86% and 70% vs 73% for group A and B patients, respectively. There were three vs one major amputations (P = .36) and eight vs seven deaths (P = .78) in group A and B patients, respectively.

CONCLUSIONS

Paclitaxel-coated and plain angioplasty of significant infrainguinal vein bypass stenoses performed equally well in clinical and hemodynamic improvement and in primary and assisted primary bypass patency rates.

Arm veins versus contralateral greater saphenous veins for lower extremity bypass reconstruction: preliminary data of a randomized study

BACKGROUND

The aim of this randomized study was to determine whether arm vein (AV) or contralateral greater saphenous vein (CGSV) is the better alternative vein source for lower extremity bypass reconstruction.

METHODS

Consecutive patients with absent ipsilateral greater saphenous vein undergoing lower extremity revascularization were allocated to group A (AV bypass) or B (CGSV bypass).

RESULTS

From 6, 2010, to 11, 2013, 64 patients (32 each group) were randomized. In all, 29 of 93 patients had to be excluded for various reasons. Median age was 76 years vs. 71 years (P = 0.01) for group A and B patients. There were no statistically significant differences regarding gender, cardiovascular risk factors, redo bypass procedures (P = 0.77), below-knee bypass procedures (P = 0.61), median bypass length (P = 0.6), and median length of incision on ipsilateral leg to perform anastomoses (P = 0.2) between group A and B patients, respectively. Incisions for vein harvest were longer in group A (P = 0.003). Overall surgical site infections (SSIs, P = 1.0) and SSI from vein harvest (P = 1.0) were equally distributed. No patient was lost to follow-up (17 vs. 18 months, P = 0.74). There was no statistically significant difference regarding primary (P = 0.77) and secondary (P = 0.25) patency rates at 1 year (group A: 52% vs. group B: 54% and group A: 72% vs. group B: 61%) and at 2 years (52% vs. 48% and 64% vs. 61%), respectively. There were 4 vs. 6 major amputations (P = 0.23) and 5 vs. 2 deaths (P = 0.1) in groups A and B during follow-up.

CONCLUSIONS

Preliminary results suggest that both AV and CGSV may serve as a secondary vein bypass graft equally well.

Successful repair of bilateral common carotid artery dissections from hanging

The management of blunt carotid artery dissections caused by hanging remains controversial, especially with regard to diagnostic work-up and treatment options. We present 2 men, 49 and 41 years of age, who were treated for bilateral common carotid artery dissection caused by strangulation. In the first patient, additional cricotracheal separation and blunt thyroid gland trauma was observed. Bilateral saphenous vein graft interposition was accomplished in both patients. In the first patient, tracheal repair and suture of the thyroid gland completed the procedure. At 1 year of follow-up, both patients were capable of managing their lives independently. A systematic review of the literature on managing near-hanging and nonfatal strangulation victims is included in this report to allow this case series to be put into perspective.

Endovascular management versus surgery for proximal subclavian artery lesions

Current management of subclavian artery (SA) lesions is controversial. Subclavian-to-carotid artery transposition (SCT) may be challenging but exhibits unparalleled long-term results. Stent-supported percutaneous transluminal angioplasty (sPTA) is technically easier but not always feasible. Long-term results and comparisons have not been published. We compared both methods performed by vascular surgeons. Data were collected prospectively with retrospective analysis at a tertiary-care center. sPTA was performed through a retrograde transbrachial access using self-expanding nitinol stents. Open surgery was SCT only. Society for Vascular Surgery/International Society of Cardiovascular Surgery reporting standards were applied. Seventy-four patients underwent treatment from January 1995 to August 2007 (median age 62.6 years, 40 female; left-sided pathology 60 [81.1%]; risk factors: hypertension 45 [60.8%], dyslipidemia 47 [63.5%], diabetes 21 [28.4%], smoking 43 [58.1%], SA occlusion 50 [67.6%]). Forty patients (54.1%) underwent primary sPTA (62.5% occlusions) and 34 SCT (73.5% occlusions). The two groups were comparable with regard to risk factors. In 12 patients occlusions could not be recanalized (30%), and in two stents failed within 1 month (both for stenosis). All but one underwent subsequent uneventful SCT. All SCTs were successful. No risk factor could be identified for treatment failure except sPTA (p = 0.002, Fisher's exact test). Median follow-up was 50.1 months with sPTA and 52.6 months with SCT. No procedure failed during follow-up in either group. sPTA can be performed successfully by surgeons. Primary sPTA failed in 48% of occlusions (30% of all sPTAs). Prediction of failure is not possible. According to our experience, we recommend primary sPTA for SA stenosis and surgery for SA occlusions.

Nephron-sparing procedures in 11 patients with Wilms' tumor

PURPOSE

In unilateral Wilms' tumor (WT), tumor nephrectomy is the standard surgical approach, whereas partial nephrectomy (PN) is controversially discussed. The aim of our retrospective study was to show that in selected cases of unilateral WT kidney-sparing operations could be a reasonable alternative to nephrectomy and to discuss the results of patients with bilateral WT treated by tumor enucleation.

MATERIALS AND METHODS

From 1981 to 1998, seven patients with unilateral nephroblastoma (four stage I, one stage III and two stage IV) had tumor resection by PN (five right side, two left side), which was planned when the tumor volume was reduced after 4 to 6 weeks of chemotherapy by at least 50%, when the tumor occupied one pole or was easily resectable, when 50% or more of the kidney tissue remained and when paraaortic lymph nodes were free by intraoperative histological examination. In four patients with bilateral WT (stage V) bilateral tumor enucleation was carried out-except in one patient in whom the contralateral kidney had to been removed because of extension of the tumor via the inferior vena cava to the right atrium. All patients ( n = 11) received pre- and postoperative chemotherapy followed by radiotherapy in four patients.

RESULTS

All patients with unilateral WT ( n = 7) are still alive and disease free (follow-up time: mean 6.6 years, range: 28 months to 11 years) with normal renal function, although two patients with secondary nephrectomy revealed creatinine clearance levels at the lower range. In six patients primary PN was performed successfully. In a stage III tumor patient (intraperitoneal metastasis, free lymph nodes), secondary nephrectomy was necessary due to renal arterial thrombosis 2 days after PN. In one stage IV tumor patient (lung metastasis, free lymph nodes), the primary resection was not far enough away from the tumor margin so that an additional slice of tissue with then tumor-free margins had to be resected. This patient evolved a local relapse 19 months after PN and had to be nephrectomised thereafter. In the group of bilateral WT patients ( n = 4), one child died 2 months after surgery during chemotherapy because of central venous line sepsis. One patient who additionally suffered from inferior vena cava tumor thrombosis extending to the right atrium making nephrectomy of the right kidney necessary developed chronic renal failure 4.7 years postoperatively. The other two stage V tumor patients have creatinine clearance levels within the normal range.

CONCLUSIONS

Kidney-sparing procedures remain the operative approach of choice in patients with bilateral WT, but bear the risk of chronic renal failure when one kidney has to be removed. PN in children with unilateral WT, carried out by an experienced surgeon, is a reasonable alternative to nephrectomy if strict guidelines such as excellent tumor response to preoperative chemotherapy and easy resectability far away from the tumor margins through healthy kidney tissue are followed. Paraaortic lymph nodes must be free of tumor invasion in order to avoid local radiotherapy. PN prevents the patient from having to have dialysis in cases of contralateral nephrectomy resulting from metachronous WT or subsequent renal trauma.

[Apophyseal fractures of the pelvis and trochanter minor in 20 adolescents and 2 young children]

From 1978 to 1999, 22 patients (17 male, 5 female) who suffered apophyseal fractures of the pelvis and femoral lesser trochanter (18 patients by avulsion, 4 patients by direct trauma) were treated. The median age of the patients was 12.5 years (range, 1-16 years). Eighteen patients were injured during sports activities. Predominantly the anterior inferior iliac spine (n = 9) was affected, followed by fractures of the femoral lesser trochanter (n = 3), periacetabular rim (n = 3), anterior superior iliac spine (n = 2), and iliac crest (n = 2), retrospectively. The diagnosis was established using plain x-ray films. The treatment was conservative in 21 patients (95%) and operative in one (5%). Of the patients, 20 (91%) were followed-up for a median interval of 12 months (3 weeks to 84 months). At follow-up, 15 patients (75%) reported that they were free of pain during sport activities, while five patients (25%), at an average time of 33 months after accident, complained of pain at the former fracture site when exercising vigorously during sport. At clinical examination no patient was found suffering from limitation of ROM (range of motion), adjacent joints, or muscular insufficiency. Plain [not readable: see text]

Bacterial translocation in short-bowel syndrome in rats

Massive intestinal resection results in short-bowel syndrome (SBS) and is associated with an increased risk of infectious complications mainly caused by the egress of intestinal bacteria to distant organs, a process termed bacterial translocation (BT). The purpose of this experimental study in rats was to investigate in different models of SBS the impact of the type of intestinal resection on bacterial growth in the residual small bowel and on the occurrence of BT. SBS was created in 30 rats either by jejunal resection (JR), by ileal resection (IR) or by ileal resection including the ileocecal valve (IR+ICV). 10 animals underwent only a sham laparotomy (SL) and served as controls. Two weeks after the operative procedure, intestinal bacterial colonization and BT to the portal vein, vena cava, mesenteric lymph nodes, liver and spleen were determined. All resected animals showed a decreased weight gain and a significant bacterial overgrowth in the residual small bowel compared to the SL group. BT occurred after SL in 12%, after JR in 70%, after IR in 58%, and was significantly less frequent (35%) after IR+ICV, respectively. These experimental findings suggest that BT in SBS might be promoted by the intestinal bacterial overgrowth in the residual bowel, and the incidence of BT seems to be related to the presence or absence of the ileocecal valve.