The prognostic impact of vascular calcification on abdominal aortic aneurysm progression.

OBJECTIVE: The maximal aortic diameter is currently the only clinically applied predictor of abdominal aortic aneurysm (AAA) progression. It is known that the risk of rupture is associated with aneurysm size; hence, accurate monitoring of AAA expansion is crucial. Aneurysmal vessel wall calcification and its implication on AAA expansion are insufficiently explored. We evaluated the vascular calcification using longitudinal computed tomography angiographies (CTA) of patients with an AAA and its association with AAA growth. METHODS: We conducted a retrospective study of 102 patients with an AAA with a total of 389 abdominal CTAs at 6-month intervals, treated and followed at the Division of Vascular Surgery, Department of General Surgery, Medical University of Vienna. Digitally stored CTAs were reviewed for vascular calcification (volume and score) of the infrarenal aorta and common iliac arteries as well as for morphometric AAA analysis. In the prognostic setting, slow versus fast AAA progression was defined as a less than 2 mm or a 2-mm or greater increase in AAA diameter over 6 months. In addition, to analyze the association of vascular calcification and the AAA growth rate with longitudinal monitoring data, a specifically tailored log-linear mixed model was used. RESULTS: An inverse relation of increased abdominal vessel wall calcification and short-term AAA progression was detected. Compared with fast progressing AAA, the median calcification volume of the infrarenal aorta (1225.3 mm³ vs 519.8 mm³; P = .003), the median total calcification volume (2014.1 mm³ vs 1434.9 mm³; P = .008), and the median abdominal total customized Agatston calcium (cAC) score (1663.5 vs 718.4; P = .003) were significantly increased in slow progressing AAA. Importantly, a log-linear mixed model efficiently predicted AAA expansion based on current diameter and abdominal total cAC score (P = .042). CONCLUSIONS: We assessed the prognostic value of CTA-measured vascular calcification for AAA progression. Increased vascular calcification stabilizes the aortic aneurysmal wall and likely protects against progressive AAA expansion, resulting in a significant decrease of aneurysm growth over time. As a consequence, this may have implications for rupture risk, mortality, morbidity, and cost.

Novel prefabricated bovine pericardial grafts as alternate conduit for septic aortoiliac reconstruction.

OBJECTIVE: Infection of prosthetic aortic grafts represents a serious complication with high morbidity and mortality. Replacement with autologous material is recommended; however, in its absence, biological material should be favored. In the present retrospective cohort study, we evaluated the short- and midterm results with the use of commercially available prefabricated bovine pericardium grafts (BPGs) used for the management of aortic graft infection or aortic reconstructive surgery in the presence of systemic infection. METHODS: We performed a retrospective analysis of patients in whom BPGs had been used for aortic reconstruction at two vascular centers. Prefabricated vascular pericardium grafts were preferred over other biological reconstruction techniques for selected cases. Comorbidities, procedure-related details, perioperative morbidity, clinical outcomes, and mortality were analyzed. RESULTS: From 2014 to 2019, 21 patients had received BPGs at two Austrian vascular centers. Their median age was 63 years (interquartile range [IQR], 55-71 years), the patients were predominantly male (76%), and the median body mass index was 25.3 kg/m2 (IQR, 21.7-27.3 kg/m2). The major comorbidities included arterial hypertension, peripheral artery disease, smoking, and chronic pulmonary disease. The indications for surgery were vascular graft or endograft infection in 62% and aortic reconstruction in the presence of systemic infection in 38%. Three patients (14%) had aortoenteric fistulas. Surgery was technically successful in all cases. The median follow-up was 21.6 months (IQR, 6.0-34.6 months). The 30-day mortality was 9.5%. The 1- and 2-year overall survival was 84% and 75%, respectively. Of the 21 patients, 89% had remained free of recurrent infection. One of the two reinfections had resolved after treatment of the underlying focus. At 2 years, the primary and assisted primary patency rates were 86% and 94%, respectively. No limbs were lost during follow-up. CONCLUSIONS: Prefabricated BPGs represent a promising alternative for the management of aortic graft infections and aortoiliac reconstruction in the presence of systemic infection.

Neutrophil Gelatinase Associated Lipocalin (NGAL) for Identification of Unstable Plaques in Patients with Asymptomatic Carotid Stenosis.

OBJECTIVE: Neutrophil gelatinase associated lipocalin (NGAL) and matrix metalloproteinase (MMP)-9/NGAL complex were investigated in asymptomatic patients with carotid artery stenosis including gender specific differences aiming at vulnerable plaques prone to embolisation. METHODS: Serum NGAL and MMP-9/NGAL levels were analysed in 83 patients with asymptomatic carotid artery stenosis. Pre-operative ultrasound and post-endarterectomy histology of carotid atherosclerotic lesions were evaluated. RESULTS: Patients with vulnerable plaques, as determined by ultrasound (plaques with decreased echogenicity) and histological analysis (type VI according to the classification of the American Heart Association), displayed the highest levels of NGAL and MMP-9/NGAL complex (p = .0003 and p = .0078, respectively). Grade VI plaques were primarily detected in patients with "soft" plaques (12 type VI plaques in 25 patients), but also in patients with mixed (four of 19) and calcified (three of 39) plaques according to ultrasound. Higher grade carotid artery stenosis (≥90%) was not associated with elevated NGAL levels. The receiver operating characteristic curve analysis detecting grade VI lesions yields an area under the curve (AUC) = 0.85, with respect to soft plaque on ultrasound the AUC = 0.86. There were no gender specific differences in levels of NGAL 80.9 (37.7) ng/mL in women vs. 76.7 (36.3) ng/mL in men, p = .607) nor of MMP-9/NGAL 33.0 (18.2-55.5) ng/mL in women vs. 36.7 (20.2-54.0) ng/mL in men, p = .969. Likewise, there were no gender associated differences in vulnerable plaque characteristics: either for grade VI plaques (17.9% vs. 27.3%, p = .582) or for the presence of soft plaques as evaluated by ultrasound (35.9% vs. 25%, p = .503). CONCLUSION: Circulating NGAL and MMP-9/NGAL are significantly increased in asymptomatic patients with vulnerable carotid atherosclerotic plaques independent of gender. Accordingly, serum NGAL may be proposed as a valuable biomarker for the detection of unstable carotid plaques in asymptomatic patients, who can then be selected for early carotid endarterectomy or stenting.

NGAL and MMP-9/NGAL as biomarkers of plaque vulnerability and targets of statins in patients with carotid atherosclerosis.

BACKGROUND: Neutrophil gelatinase associated lipocalin (NGAL) is expressed in atherosclerotic lesions and was recently implicated in the pathogenesis of cardiovascular pathologies. Statins are known to exert stabilizing effects on atherosclerotic plaque. The aims of our study were (1) to investigate the association of serum NGAL and metalloproteinase (MMP)-9/NGAL complex with the vulnerability of the atherosclerotic plaque, and (2) to reveal the effects of statin treatment on circulating NGAL and MMP-9/NGAL levels in patients with carotid artery stenosis. METHODS: We examined the levels of NGAL and MMP-9/NGAL in blood samples from 136 patients with carotid artery stenosis by specific enzyme-linked immunosorbent assays. RESULTS: Patients with vulnerable plaques, as determined by ultrasound (plaques with decreased echogenicity) and histological analysis (type VI according to the classification of American Heart Association [AHA]), displayed the highest levels of NGAL (both p<0.0001) and MMP-9/NGAL complex (p=0.0004 and p=0.004, respectively). Moreover, patients with symptomatic carotid atherosclerosis had significantly higher NGAL levels compared to asymptomatic patients (p=0.0007). The statin-treated group (n=108) demonstrated lower NGAL (73.9 vs. 128.0 µg/L, p<0.0001) and MMP-9/NGAL (28.9 vs. 40.6 µg/L, p=0.046) as compared to the non-statin group (n=28). Furthermore, in multivariate regression analysis NGAL, but not MMP-9/NGAL levels, were independently associated with symptomatic carotid artery stenosis. In addition, statin treatment was independently associated with lower NGAL levels. CONCLUSIONS: Circulating NGAL and MMP-9/NGAL are associated with plaque vulnerability in patients with carotid artery stenosis. Statin treatment could contribute to plaque stabilization by reducing circulating NGAL and MMP-9/NGAL levels.

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.

Comparing maximum diameter and volume when assessing the growth of small abdominal aortic aneurysms using longitudinal CTA data: cohort study.

BACKGROUND: Monitoring of abdominal aortic aneurysms (AAAs) is currently based on serial measurements of maximum aortic diameter. Additional assessment of aneurysm volume has previously been proposed to possibly improve growth prediction and treatment decisions. To evaluate the use of supplementing volume measurements, the authors aimed to characterise the growth distribution of AAA volume and to compare the growth rates of the maximum diameter and volume at the patient level. METHODS: Maximum diameter and volume were monitored every 6 months in 84 patients with small AAAs, with a total of 331 computed tomographic angiographies (with initial maximum diameters of 30-68 mm). A previously developed statistical growth model for AAAs was applied to assess the growth distribution of volume and to compare individual growth rates for volume and for maximum diameter. RESULTS: The median (25-75% quantile) expansion in volume was 13.4 (6.5-24.7) % per year. Cube root transformed volume and maximum diameter showed a closely linear association with a within-subject correlation of 0.77. At the surgery threshold maximum diameter of 55 mm, the median (25-75% quantile) volume was 132 (103-167) ml. In 39% of subjects, growth rates for volume and maximum diameter were equivalent, in 33% growth was faster in volume and in 27% growth was faster in maximum diameter. CONCLUSION: At the population level, volume and maximum diameter show a substantial association such that the average volume is approximately proportional to the average maximum diameter raised to a power of three. At the individual level, however, in the majority of patient's AAAs grow at different pace in different dimensions. Hence, closer monitoring of aneurysms with sub-critical diameter but suspicious morphology may benefit from complementing maximum diameter by volume or related measurements.

Evaluation of national institute for health and care excellence guidance for ruptured abdominal aortic aneurysms by emulating a hypothetical target trial.

Objective: This retrospective study evaluates the performance of UK National Institute for Health and Care Excellence (NICE) Guidelines on management of ruptured abdominal aortic aneurysms in a "real world setting" by emulating a hypothetical target trial with data from two European Aortic Centers. Methods: Clinical data was retrospectively collected for all patients who had undergone ruptured endovascular aneurysm repair (rEVAR) and ruptured open surgical repair (rOSR). Survival analysis was performed comparing NICE compliance to usual care strategy. NICE compliers were defined as: female patients undergoing rEVAR; male patients >70 years old undergoing rEVAR; and male patients ≤70 years old undergoing rOSR. Hemodynamic instability was considered additionally. Results: This multicenter study included 298 patients treated for rAAA. The majority of patients were treated with rOSR (186 rOSR vs. 112 rEVAR). Overall, 184 deaths (68 [37%] with rEVAR and 116 [63%] with rOSR) were observed during the study period. Overall survival under usual care was 69.2% at 30 days, 56.5% at one year, and 42.4% at 5 years. NICE compliance gave survival outcomes of 73.1% at 30 days, 60.2% at 1 year and 42.9% at 5 years. The risk ratios at these time points, comparing NICE-compliance to usual care, were 0.88, 0.92 and 0.99, respectively. Conclusions: We support NICE recommendations to manage men below the age of 71 years and hemodynamic stability with rOSR. There was a slight survival advantage for NICE compliers overall, in men >70 years and women of all ages.

Prospective evaluation of high-resolution MRI using gadofosveset for stent-graft planning: comparison with CT angiography in 30 patients.

OBJECTIVE: The purpose of our study was to compare high-resolution gadofosveset-enhanced MR angiography (MRA) with the reference standard CT angiography (CTA) in planning endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms. SUBJECTS AND METHODS: Thirty consecutive patients were included in this prospective study. CTA was performed routinely before EVAR for stent-graft implantation planning and selection. In addition, first-pass and, after a delay of 10 minutes, steady-state MRA were performed using the blood pool contrast agent gadofosveset for study purposes. Standard diameter and length parameters for stent-graft evaluation rendered from CTA and MRA were compared. According to the results of MRA measurements, stent-grafts were selected for each patient and compared with the device actually implanted. Image quality was assessed using subjective image quality parameters. RESULTS: Diameter and length measurements showed small but significant differences (p < 0.001) between MRA and CTA. Stent-graft selection according to these measurements showed 100% concordance between both modalities. Subjective imaging parameters showed significantly better results for CTA compared with MRA (p < 0.001). CONCLUSION: In this study, MRA using a blood pool contrast agent has shown the ability to provide reliable and exact measurements before EVAR, allowing noninvasive planning of the intervention despite lower image-quality and without the disadvantages of ionizing radiation and nephrotoxicity.

Complement Factor C5a Is Increased in Blood of Patients with Abdominal Aortic Aneurysm and Has Prognostic Potential for Aneurysm Growth.

In this observational case-control study, circulating levels of complement factors C3a and C5a and leukotriene B4 (LTB4) were analysed in abdominal aortic aneurysm (AAA) patients regarding their association with diagnosis and prognosis. Serum C5a was significantly raised in AAA patients compared to healthy controls-median 84.5 ng/ml (IQR = 37.5 ng/ml) vs. 67.7 ng/ml (IQR = 26.2 ng/ml), p = 0.007-but was not elevated in patients with athero-occlusive disease. Serum C5a levels correlated significantly with the increase in maximum AAA diameter over the following 6 months (r = 0.319, p = 0.021). The median growth in the lowest quartile of C5a (< 70 ng/ml) was 50% less compared to the highest C5a quartile (> 101 ng/ml): 1.0 mm/6 months (IQR = 0.8 mm) vs. 2.0 mm/6 months (IQR = 1.5 mm), p = 0.014. A log-linear mixed model predicted AAA expansion based on current diameter and C5a level. To our knowledge, this is the first study linking complement activation, in particular C5a serum level, with AAA progression.

Inverse probability of treatment analysis of open vs endovascular repair in ruptured infrarenal aortic aneurysm - Cohort study.

BACKGROUND: To compare open repair (OR) with EVAR for the management of ruptured infrarenal abdominal aortic aneurysms (RAAA) in a cohort study over a time period of 15 years with inverse probability of treatment weights. MATERIAL AND METHODS: From 2000/01 through 2015/12 136 patients were treated for RAAA, 98 (72.1%) underwent OR, 38 (27.9%) were treated with EVAR. Thirty-day and long-term mortality (survival) were analyzed in this IRB-approved retrospective cohort study. Treatment modalities were compared using inverse probability of treatment weights to adjust for imbalances in demographic data and risk factors. RESULTS: EVAR patients were older (75.11 ± 7.17 vs 69.79 ± 10.24; p=0.001). There was no statistical difference in gender, hypertension, COPD, CAD, or diabetes. GFR was significantly higher in OR patients (71.4 ± 31.09 vs. 53.68 ± 25.73). Postoperative dialysis was required more frequently in EVAR patients: 11% vs. 2% (p = 0.099). In the OR group, adjusted cumulative survival was 70.4% (61.1, 81.1) at 30 days, 47.0% (37.1, 59.6) at one year and 38.3% (28.6, 51.3) at 5 years. In the EVAR group the corresponding numbers were 77.0% (67.7, 87.5), 67.5% (57.0, 80.0) and 41.7% (30.4, 57.4), respectively. CONCLUSION: There is evidence for EVAR patients exhibiting a benefit in one-year survival, while patients treated with OR may have more favorable long-term survival given they survive for at least one year. Herein we provide a statistically rigorous comparison of OR and EVAR in short and long-term outcomes with up to 15 years of follow-up.

Does the choice of intraoperative fluid modify abdominal aneurysm repair outcomes?: A cohort analysis.

Intraoperatively administered hydroxyethyl starch could be a risk indicator for postoperative acute kidney injury (AKI) in vascular surgical patients.In a single-center retrospective cohort analysis, we assessed the impact of hydroxyethyl starch and other risk indicators on AKI and mortality in 1095 patients undergoing elective open abdominal aneurysm repair (AAA-OR) or endovascular aortic repair (EVAR). We established logistic regression models to determine the effect of various risk indicators, including hydroxyethyl starch, on AKI, as well as Cox proportional hazard models to assess the effect on mortality.The use of intravenous hydroxyethyl starch was not associated with an increased risk of AKI or mortality. Patients undergoing EVAR were less likely to develop AKI (4% vs 18%). Multivariate risk indicators associated for AKI included suprarenal or pararenal aortic cross-clamp [odds ratio (OR), 4.44; 95% confidence interval (95% CI), 2.538-7.784; P < .001] and procedure length (OR, 1.005; 95% CI, 1.003-1.007; P < .001), and favored EVAR (OR, 0.351; 95% CI, 0.118-0.654; P < .01). Main multivariate risk indicators associated with mortality included patients needing an urgent procedure [hazard ratio (HR), 2.294; 95% CI, 1.541-3.413; P < .001], those with suprarenal or pararenal aortic cross-clamp (HR, 1.756; 95% CI, 1.247-2.472; P < .01), and patients undergoing EVAR (HR, 1.654; 95% CI, 1.292-2.118; P < .001).We found neither a benefit nor a negative effect of hydroxyethyl starch on the risk of AKI or mortality. Instead, other variables and comorbidities were found to be relevant for the development of postoperative AKI and survival. Nevertheless, clinicians should be aware of the high risk of postoperative AKI, particularly among those undergoing AAA-OR procedures.

Imaging of a case of benign carotidynia with ultrasound, MRI and PET-CT.

We present a case of carotidynia that we believe supports its classification as a distinct inflammatory disease entity. Doppler sonography and cervical magnetic resonance imaging are appropriate imaging modalities for diagnosing presumed carotidynia.

Redo pedal bypass surgery after pedal graft failure: gain or gadget?

Pedal bypass failure is not always associated with limb loss. Management of critical limb ischemia after failure is controversial. The aim of this study is to evaluate the results of redo bypass procedures to foot arteries in the absence of alternative tibial outflow arteries. Data of patients undergoing redo pedal bypass within a 14-year period were reviewed. The outcome after redo pedal bypass in patients whose original pedal bypass failed within 30 days versus those in patients whose original pedal bypass failed more than 30 days after the original pedal bypass were reviewed. Society for Vascular Surgery reporting standards were applied. Out of 335 pedal bypass grafts, 22 (6.6%) pedal redo bypass procedures were identified in 20 patients performed after previous pedal graft failure: 64% were male, mean age 67.7 +/- 9.5 years, diabetes 90.9%, hypertension 90.9%, coronary disease 68.2%, renal disease 18.2%. Seven patients were operated for early failure and 15 for late failure (median 193 days). The graft conduit at the first operation was ipsilateral greater saphenous vein (GSV) in 18 (81.8%), alternative vein in three (13.6%), and one expanded polytetrafluoroethylene. Redo graft conduits were as follows: ipsilateral GSV in nine (40.9%), arm vein in six (27.3%), contralateral GSV in two (9.1%), "other veins" in two (9.1%), and homologous artery in three (13.6%). The same target artery was used in 81.8%, at the initial site in 54.5% and more distally in 27.3%. Redo revascularization for early failure was successful only once. Median follow-up after late redo was 23.7 months. Seven redo grafts performed after late pedal graft failure failed after a median of 115 days. The availability of adequate autologous conduit is the limiting factor for redo procedures. Lack of alternative outflow sites adds to the difficulty of target artery dissection. Redo pedal bypass surgery after early pedal bypass failure is associated with very poor patency and limb salvage. Acceptable patency and extension of limb salvage can be achieved with redo procedures for late pedal bypass failure.

Management of iatrogenic common femoral artery injuries in pediatric patients using primary vein patch angioplasty.

BACKGROUND: Invasive therapeutic and diagnostic procedures remain the most frequent causes of pediatric vascular injuries. Ideal management, especially the indication for surgical treatment, remains controversial. This study evaluates the outcome of surgical repair for iatrogenic common femoral artery (CFA) injuries in pediatric patients using primary vein patch angioplasty. METHODS: From January 1996 through February 2006, 8 patients were identified in the vascular registry of the Vienna General Hospital in Austria. A retrospective office chart review was performed on this consecutive series of patients treated for iatrogenic CFA injuries using primary vein patch angioplasty. RESULTS: The mean age was 5.8 years (range, 0.3-10.9 years). Surgical repair was performed for 5 ischemic limbs and 3 pseudoaneurysms. Urgent repair was necessary in 5 children (62.5%). After a median follow-up of 9 months (range, 1.8-77.6 months), palpable pedal pulses were present in all patients. No aneurysmatic degeneration of vein patches occurred, and no patient sustained any additional sequelae related to the arterial reconstruction. CONCLUSION: Routine use of a vein patch eases CFA repair, especially in the very young.

Influence of direct and indirect allorecognition pathways on CD4+CD25+ regulatory T-cell function in transplantation.

While both direct and indirect allorecognition are involved in allograft rejection, evidence to date suggests that tolerance is primarily dependent on indirect pathway-triggered CD4+CD25+ T cell-mediated immunoregulation. However, the precise influence of these two pathways on CD4+CD25+ T-cell function has not been addressed. In the current study, we have utilized an adoptive transfer model to assess selectively how the absence of either direct or indirect allorecognition affects CD4+CD25+ T-cell function. The effects of the loss of the direct pathway were assessed by transplanting skin grafts from minor histocompatibility mismatched B10.D2 (H-2d) donors onto Balb/c (H-2d) recipients, or by placing bone marrow chimeric DBA/2 (H-2d/H-2b) allografts onto C57BL/6 (H-2b) hosts. The requirement for indirect allorecognition was tested by grafting DBA/2 skin allografts onto either C57BL/6- or MHC-II-deficient C57BL/6 recipients. We report here that although CD4+CD25+ regulatory T cells can suppress both directly and indirectly generated alloresponses, immunoregulation is favored when indirect presentation is the sole mechanism of allorecognition. Hence, in the absence of indirect presentation, net CD4+CD25+ T cell-dependent immunoregulation is weak, and high ratios of CD4+CD25+ to CD4+CD25 T cells are required to ensure graft survival.

Endovascular repair of the thoracic aorta necessitating anchoring of the stent graft across the arch vessels.

OBJECTIVE: The purpose of the study was to determine technical and clinical results in endovascular repair of thoracic aortic diseases necessitating stent-graft anchoring across the arch vessels. METHODS: The causes for endovascular treatment in 58 patients (aged 20 to 84 years) were aneurysms (n = 32), acute type A (n = 2) and type B dissections (n = 17), posttraumatic transections (n = 4), iatrogenic dissection (n = 1), and penetrating ulcers with an intramural hematoma (n = 2). Surgical revascularization of arch vessels was performed in 26 patients before stent-graft implantation. Intentional overstenting of the left subclavian artery resulted in complete occlusion in 8 and was partial in 24 patients. RESULTS: The 30-day mortality rate was 3.4%. Overall, 19 major postprocedural complications occurred in 14 (24%) patients. Among patients with left subclavian artery occlusion, 2 patients had major (1 paraplegia, 1 critical arm ischemia), and 3 minor (2 temporary vertebrobasilary symptoms, 1 transient arm claudication) complications. Fourteen (25%) patients had an early endoleak, of whom 5 were treated successfully with a secondary endovascular procedure, 2 necessitated open surgical conversion, and 7 were treated conservatively, with spontaneous sealing of the endoleak in 3. In 53 (91%) in whom computed tomographic follow-up was longer than 3 months (mean, 30.1 months, range, 3 to 85), the aortic diameter along the stented segment decreased in 24, was stable in 19, and increased in 10 patients. CONCLUSION: Fixation of the stent graft in the aortic arch can expand the applicability of endovascular repair. Intentional overstenting should be performed with caution to avoid ischemic problems after complete occlusion of left subclavian artery.

Timing of pedal bypass failure and its impact on the need for amputation.

Although the utility of dorsalis pedis (DP) bypass for limb ischemia has been well established, the fate of limbs with a failed bypass to the DP artery remains unclear. Data of all patients undergoing DP bypass grafting within a 12-year period from two university hospitals' vascular registries were retrospectively reviewed. Outcomes of early (<30 days) and delayed graft failure (>30 days) were examined. The Student's t-test and chi-squared test were used for univariate analysis; patency rates and patient survival were calculated using the Kaplan-Meier product limit method. Of 1434 DP bypass grafts, 277 (19.3%) failed grafts were identified. Sixty five (4.5%) grafts failed early (within 30 days of surgery) and 212 (14.8%) failed late at a mean time of 15.3 months (range, 1.5-105 months) after initial bypass. Of the 65 limbs with early graft failure, 28 (43.1%) proceeded directly to amputation and 20 underwent additional revascularization attempts, but limb salvage was achieved in only 7 patients; in 45 (69.2%) patients no further revascularizations were attempted. Seventy-four (34.9%) patients with late graft failure underwent redo revascularization. Thirty-nine (52.6%) had their limb saved with graft revision, but 35 patients (47.3%) ultimately lost their limb. In 138 patients with late graft failure (65.1%) no further revascularization attempts were performed. Sixty-two (44.9%) required major amputation. Overall, 49.8% of patients with failed pedal grafts ultimately suffered limb loss. Early graft failure resulted in a significantly higher rate of major amputation that did late graft failure (63.1% vs. 45.8%, respectively; p = 0.015). These results indicate that early occlusion of pedal bypass often leads to immediate major amputation and interventions to maintain graft patency in this setting are often futile. Late failure of pedal bypass is associated with a lower likelihood of amputation because of a higher rate of success of bypass revisions and a lower occurrence of critical ischemia with graft failure.

Anatomic basis of right renal vein extension for cadaveric kidney transplantation.

OBJECTIVES: The right renal vein (RRV) may be difficult to anastomose in right cadaveric kidney transplantation, especially in obese recipients in whom iliac vessels are deep. In this study, gain of length and feasibility in the presence of vascular variations obtained with three common techniques of renal vein augmentation--clamshell (CS), transverse closure of the inferior vena cava (TC), and cava conduit (CC)--were analyzed and compared to the Carrel-patch technique. METHODS: The renal vasculature and the inferior vena cava of 119 cadavers were accurately dissected and measured, and the vascular variations documented. The CS technique augmented the RRV at most by one fourth, the TC by one half the diameter of the inferior vena cava, and the CC by the length of the infrarenal inferior vena cava. An experienced transplant surgeon evaluated the situs for the feasibility of the techniques. RESULTS: The variations found were multiple veins (right, 23%; left, 6.7%), a retroaortal left vein (2.5%), a renal collar (6%); and multiple arteries (right, 20.2%; left, 19%). The RRV length varied from 21 to 71 mm, and the right renal artery (RRA) length varied between 44 and 111 mm. The RRA/RRV ratios ranged between 3.4 and 1.2. The achieved gains of length were 129% with the CS (possible in 81.5%), 190% with the TC (possible in 62.4%), and 388.4% with the CC (possible in 80.7%). CONCLUSIONS: The median RRV is one half the RRA in length so that length augmentation could be an advantage. Anatomic variations limit the choice of technique. Overall, augmentation was possible in 80%; the CS technique seldom resulted in a length equal to that of the RRA, the TC was the most susceptible to variations, and the CC always surpassed the RRA in length. Harvesting the RRV en bloc with the inferior vena cava enables the surgeon to best adapt donor vessels to the recipient's anatomy.

Bypass to plantar and tarsal arteries: an acceptable approach to limb salvage.

OBJECTIVE: This study was undertaken to evaluate our experience with distal arterial bypass to the plantar artery branches and the lateral tarsal artery for ischemic limb salvage. METHODS: This was a retrospective analysis of data prospectively entered into our vascular surgery database from January 1990 to January 2003 for all consecutive patients undergoing bypass grafting to the plantar artery branches or the lateral tarsal artery. Median follow-up was 9 months (range, 1-112 months). Demographic data, indications for surgery, outcomes, and patency were recorded, and statistical analysis was performed to assess significance. RESULTS: Ninety-eight bypass procedures to either the medial plantar artery, lateral plantar artery, or lateral tarsal artery were performed in 90 patients. Eighty-one patients (83%) were men. Mean age was 67.5 +/- 11.6 years. Indications for operation were tissue loss in 93 patients (95%), rest pain in 3 patients (3%), and failing graft in 2 patients (2%). Eighteen patients (18%) had previously undergone vascular reconstruction, and 5 patients (5%) had undergone previous bypass to the dorsalis pedis artery. Seventy-one grafts (72%) had inflow from the popliteal artery, 25 grafts had inflow from a femoral artery or graft (26%), and 2 grafts had inflow from a tibial artery (2%). Conduits used were greater saphenous vein in 67 patients (69%), arm vein in 20 patients (20%), composite vein in 10 patients (10%), and polytetrafluoroethylene conduit in 1 patient (1%). There were 77 bypasses (79%) to plantar artery branches, and 21 bypasses (21%) to the lateral tarsal artery. Thirty-day mortality was 1% (1 of 98 procedures). Early graft failure within 30 days occurred in 11 patients (11%). In the subset of patients with a previous arterial reconstruction, there were 2 early graft failures within 30 days (11%). Both occurred in patients who had undergone previous bypass to the dorsalis pedis artery. Primary patency, secondary patency, limb salvage, and patient survival were 67%, 70%, 75%, and 91%, respectively, at 12 months, and 41%, 50%, 69%, and 63%, respectively, at 5 years, as determined from Kaplan-Meier survival curves. Greater saphenous vein grafts performed better than all other conduits, with a secondary patency rate of 82% versus 47% at 1 year (P = .009). CONCLUSION: Inframalleolar bypass to plantar artery branches and the lateral tarsal artery, even in patients with a previously failed revascularization, can be undertaken with acceptable patency and limb salvage rates. Early graft failure, however, is higher, whereas patency and limb salvage rates are lower, compared with bypass to the dorsalis pedis artery. The use of saphenous vein as a conduit results in the best patency for plantar or lateral tarsal bypass procedures.