Multilevel thrombotic or embolic burden and its role in sex-related outcomes in acute limb ischemia.

OBJECTIVE: The impact of sex upon outcomes in acute limb ischemia (ALI) remains disputed. We aim to quantify the effect of sex upon amputation-free survival (AFS) after a percutaneous-first approach for ALI. METHODS: This was a two-center retrospective review of ALI managed via a percutaneous-first approach. Demographics, comorbidities, and clinical characteristics were analyzed. The Kaplan-Meier and Cox regression were used to estimate AFS, limb salvage, and overall survival. RESULTS: Over 9 years, 170 patients (n = 87, 51% males; median age, 67 [interquartile range (IQR), 59-77 years) presented with ALI. Rutherford classification was I in 56 (33%); IIa in 85 (50%); IIb in 20 (12%), and III in 9 (5%). Thirty-day mortality, major amputation rate, and fasciotomy rates were 8% (n = 13); 6.5% (n = 11), and 4.7% (n = 8), respectively. Among revascularized limbs, 92% were patent at 30 days. Length of stay was 7 days (IQR, 3-11 days). Complications included 13 bleeding episodes (8%), four cases of atrial fibrillation (2%), and three re-thrombosis/clot extension events (1.7%). No differences were noted in complication rates when stratified by sex. Females were older than males (median age, 70 [IQR, 62-79] vs 65 [IQR, 56-76 years]; P = .02) and more likely to present with atrial fibrillation (20.5% vs 8%; P = .02) and hyperlipidemia (72% vs 57%; P = .04). Females also more frequently presented with multi-level thrombotic/embolic burden compared with males (56% vs 43%; P = .03) and required both aspiration thrombectomy and thrombolysis (27% vs 14%; P = .02). Kaplan-Meier estimated median AFS, limb salvage, and overall survival were 425 days (IQR, 140-824 days); 314 days (IQR, 72-727 days); and 342 days (IQR, 112-762 days). When stratified by sex, females had worse survival (median, 270 days [IQR, 92-636 days] vs 406 days [IQR, 140-937 days]; P = .005) and limb salvage (median, 241 days [IQR, 88-636 days] vs 363 days [IQR, 49-822 days]; P = .04) compared with males. Univariate Cox regression showed female sex (hazard ratio [HR], 1.46; 95% confidence interval [CI], 1.04-2.05; P = .03), multi-level thrombotic/embolic burden (HR, 1.64; 95% CI, 1.17-2.31; P = .004), and Rutherford class (HR, 1.37; 95% CI, 1.08-1.73; P = .009) predicted major amputation/death. By multivariable Cox regression, multi-level thrombotic/embolic burden (HR, 1.54; 95% CI, 1.09-2.17; P = .01), Rutherford class (HR, 1.34; 95% CI, 1.07-1.69; P = .01), and female sex (HR, 1.45; 95% CI, 1.03-2.05; P = .03) were each independently predictive of major amputation/death. CONCLUSIONS: A percutaneous-first strategy is safe and efficacious in the overall ALI population. Similar to prior works, female vs male patients with ALI in our cohort have higher rates of mortality and major amputation. In our multivariable model, multi-level thrombotic/embolic burden was independently associated with a greater than 45% increased hazard of major amputation/death at last follow-up. Further prospective analysis is warranted to elucidate the underlying factors contributing to the higher prevalence of multi-level thrombotic/embolic burden in female patients with ALI, and to further define the optimal percutaneous-first approach for ALI in consideration of patient sex and extent of clot burden.

Independent associations with early mortality after open repair of Crawford extent IV thoracoabdominal aortic aneurysms.

OBJECTIVE: We aimed to identify outcomes and factors that independently associate with early mortality after open repair of Crawford extent IV thoracoabdominal aortic aneurysms, defined as aneurysms confined to the segment below the diaphragm. METHODS: This retrospective analysis included 721 extent IV thoracoabdominal aortic aneurysm repairs performed in our institution from 1986 to 2021. Indications for repair were aneurysm without dissection in 627 cases (87.0%) and aortic dissection in 94 cases (13.0%). Overall, 466 patients (64.6%) were symptomatic preoperatively; 124 (17.2%) procedures were performed in patients with acute presentation, including 58 (8.0%) ruptured aneurysms. RESULTS: Operative death occurred after 49 (6.8%) repairs. Persistent renal failure necessitating dialysis occurred after 43 (6.0%) repairs. Binary logistic regression modeling revealed that previous extent II thoracoabdominal aortic aneurysm repair, chronic kidney disease, previous myocardial infarction, urgent or emergency repair, and longer crossclamp times during surgery were independently associated with operative mortality. Among early survivors (n = 672), competing risk analysis revealed that cumulative incidence of mortality and reintervention rates at 10 years were 74.8% (95% confidence interval, 71.4%-78.5%) and 3.3% (95% confidence interval, 2.2%-5.1%), respectively. CONCLUSIONS: Although patient comorbidities contributed to operative mortality, factors associated with the repair, such as urgent or emergency status, the duration of aortic crossclamping, and certain types of complex reoperation, also played prominent roles. Patients who survive the operation can expect a durable repair that usually is free from late reintervention. Expanding our collective knowledge regarding patients who undergo open repair of extent IV thoracoabdominal aortic aneurysms will enable clinicians to establish best practices and improve patient outcomes.

Iliocaval outflow obstruction in patients with venous ulcers in a small comparison study between patients with primary varicose veins and chronic deep vein disease.

OBJECTIVE: Iliocaval outflow obstruction was investigated in patients with venous ulcers caused by primary superficial disease and chronic deep vein disease METHODS: After clinical assessment, patients with healed or active venous leg ulcers underwent lower extremity duplex ultrasound examination to identify the presence of venous disease in the superficial, deep and perforating systems. Bilateral contrast venography and intravascular ultrasound examination were then performed to determine the presence and degree of iliocaval obstructive lesions. RESULTS: This retrospective study included a total of 59 patients with 71 legs presenting active or healed ulcer. There were 16 limbs (22.5%) with superficial venous reflux associated with normal infrainguinal deep veins (group I) and 55 limbs (77.5%) with infrainguinal post-thrombotic deep venous disease (group II). Using venography and intravascular ultrasound examination, the incidence of >50% of venous obstruction in the iliocaval system in groups I and II were 75% and 83.6%, respectively. All obstructive lesions in group I were nonthrombotic. However, group II included thrombotic, nonthrombotic and combinations of the two types of obstructions. Group II had more ulcers (1.73 ± 1.3 vs 1.17 ± 0.5; P = .03), larger ulcers (>6 cm in 34.1% vs 8.3%), longer duration of ulcers (71.3 ± 110.5 months vs 37.9 ± 40.4 months; P = .03), smaller diameter of refluxing superficial veins (7.7 ± 2.6 mm vs 15.1 ± 6.6 mm; P = .001), and higher incidence of occluded iliocaval systems (18 [32.7%] vs 0; P = .003) than group I. After the exclusion of bilateral cases and thrombotic obstructions, the incidence of >50% nonthrombotic obstruction in ipsilateral and contralateral sides was 76.5% and 24.4%, respectively (P = .003). CONCLUSIONS: The results of this study revealed that the majority of patients with venous ulcers with either infrainguinal primary superficial or post-thrombotic deep venous disease had an element of iliocaval venous obstruction.

The frozen elephant trunk technique in acute DeBakey type I aortic dissection.

Although advances in the field of cardiovascular surgery have improved outcomes for patients with acute DeBakey type I aortic dissection, postoperative in-hospital mortality and morbidity remain substantial. The frozen elephant trunk technique has become a treatment option for this disease and was developed primarily to extend repair into the proximal descending thoracic aorta during aortic arch repair (because the descending thoracic aorta is largely inaccessible via median sternotomy), thus avoiding, delaying, or facilitating subsequent repair of residual native aorta. In this review, we discuss the evidence for and future development of frozen elephant trunk reconstruction for acute DeBakey type I aortic dissection.

Clinical Characteristics and Surgical Outcomes of Limb-Sparing Surgery with Vascular Reconstruction for Soft Tissue Sarcomas.

BACKGROUND: The standard treatment for lower extremity soft tissue sarcoma (STS) is limb-sparing surgery. For a small subset of patients, concomitant vascular reconstruction may be required to preserve limb viability and function while completely excising the tumor with an adequate resection margin. The aim of this study was to evaluate the surgical outcomes and clinical characteristics of patients with STS of the extremities requiring vascular reconstructions. METHODS: From January 2002 through December 2014, 13 patients with limb STS presenting with vascular invasion underwent surgical resection, followed by vascular reconstruction. The medical records such as demographics, histopathological findings, complications, success of vascular reconstruction, and clinical and oncological outcomes were retrospectively reviewed from a prospectively collected clinical database. RESULTS: With a mean follow-up period of 80.6 months, a total of 24 vascular reconstruction procedures (1 only arterial, 1 only venous, and 11 both arterial and venous) were performed. Contralateral great saphenous vein graft was the conduit of choice for vascular replacement. Five graft thromboses were observed in 4 patients. Arterial occlusion occurred in two cases, and venous bypasses occluded in three patients. The overall five-year patency for arterial and venous reconstructions was 84.6% and 75.2%, respectively. The mean survival period of patients was 105.5 months, with a 5-year disease-free survival rate and overall survival rate of 59.3% and 68.4%, respectively. CONCLUSIONS: Vascular resection and reconstruction for STSs of extremity can be safely performed with acceptable short- and long-term surgical and oncological outcomes. Regardless of the surgical procedure, amputation or limb-sparing surgery, the primary focus should be to adhere to strict oncological principles. In addition, because of the complexity of these tumors, an appropriate preoperative planning and meticulous multidisciplinary approach are also crucial.

Role of microcirculatory function and plasma biomarkers in determining the development of cardiovascular adverse events in patients with peripheral arterial disease: A 5-year follow-up.

OBJECTIVE: The aim of this long-term follow-up study was to investigate the association of local and systemic cardiovascular complications with endothelium-dependent and-independent microvascular relaxations and blood biomarkers and biochemicals in patients with peripheral arterial disease (PAD) caused by atherosclerosis. METHODS: This prospective study included 67 patients with PAD who had not undergone any endovascular intervention, peripheral arterial surgery, or major amputation. Changes in the microvascular blood flow were measured using laser Doppler imaging after iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP). The biochemical markers of high sensitivity C reactive protein (hs-CRP), nitric oxide (NO), total antioxidant capacity (TAC), asymmetric dimethyl arginine (ADMA), and hydrogen sulfide (H2S) levels were measured from blood samples. All the patients were followed up for 5 years to determine the development of cardiovascular adverse events (CVAEs) and major amputation. At the end of the follow-up period, the patients were classified into two groups: those who had a CVAE [CVAE (+)] and those who did not experience CVAE [CVAE (-)]. Parameters such as demographic features, atherosclerotic risk factors, chronic ischemia category, microvascular endothelial functions, and plasma biomarkers were compared between the groups. RESULTS: A total of 67 patients comprising 61 (91%) males and 6 (9%) females with a mean age of 62.3±9.7 years were included. During the follow-up period, 29 patients had CVAE (43.3%) and 38 patients did not have CVAE (56.7%). There was no difference between the groups in terms of ACh and SNP-induced vasodilation responses. Plasma high density lipoprotein (HDL) cholesterol values were lower in the CVAE (+) group [(CVAE+HDL: 38.4±9.1), (CVAE-HDL: 44.7±11.1), p=0.02]. Plasma hs-CRP values were significantly higher in the CVAE (+) group [(CVAE+ hs-CRP: 14.3±20.6), (CVAE-hs-CRP: 5.9±10.9), p=0.004]. No significant difference was observed between the groups in terms of plasma biomarkers and other biochemical levels. CONCLUSION: Based on the study findings, it was concluded that only low plasma HDL and high hs-CRP levels were risk factors for the development of CVAEs during follow-up of patients with PAD.

Venous stent placement ameliorates cutaneous microvascular function in iliocaval venous obstruction.

BACKGROUND: The role of cutaneous microvascular dysfunction is well known in the development of chronic venous disease. However, the effects of venous obstruction on microcirculation have not been well investigated. The aim of this study was to assess cutaneous microvascular function in patients with iliocaval venous obstruction (ICVO) before and after venous stent placement. METHODS: Endothelium-dependent and endothelium-independent vasodilator responses to iontophoretic administration of incremental doses of acetylcholine (ACh) and sodium nitroprusside (SNP) were evaluated using a laser Doppler scanner in the perimalleolar region in the supine and sitting positions in patients with ICVO (n = 11) and in healthy control subjects (n = 15). Cutaneous microvascular function, the Venous Clinical Severity Score (VCSS), and the Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) clinical class were re-evaluated 3 months after stent placement in patients with ICVO. RESULTS: The vasodilatory responses to ACh and SNP in the cutaneous microcirculation were lower in patients with ICVO than in healthy subjects in the sitting position (P < .05). Recanalization and stent placement were successful in all patients in the evaluation of VCSS and clinical class, and a significant decrease was determined in the signs and symptoms of the venous disease (P < .01). Stent placement resulted in a significant increase in vasodilation response to both ACh and SNP in the supine position and no improvement in the sitting position in patients with ICVO. CONCLUSIONS: ICVO impairs endothelium-dependent and endothelium-independent vasodilation in the perimalleolar region. Iliocaval venous stent placement may recover microvascular dysfunction at different levels.

Diagnostic value of the femoral vein flow pattern for the detection of an iliocaval venous obstruction.

OBJECTIVE: Identification of iliocaval obstructions has traditionally been difficult due to the lack of a reliable noninvasive screening technique. Although femoral vein flow patterns have been used to detect outflow obstructions, the diagnostic accuracy of indirect Doppler parameters has not yet been fully elucidated. The purpose of this study was to establish the diagnostic value of the femoral vein waveform in detecting chronic iliocaval venous lesions. METHODS: Medical records of consecutive patients with chronic venous disease classified as Clinical, Etiologic, Anatomic, and Pathophysiologic (CEAP) C3-6 between March 2011 and December 2012 were assessed retrospectively. The results of common femoral vein duplex ultrasound examinations, based on the presence or absence of respiratory variation in the femoral flow as well as its response to the Valsalva maneuver, were compared with contrast venography and intravascular ultrasound imaging of the inferior vena cava and the bilateral common and external iliac veins. Three types of flow patterns in the common femoral vein were identified with duplex ultrasound examination: phasic flow correlated with respiration, minimally phasic flow (showing some phasicity but no cessation with respiration), and monophasic flow (continuous flattened flow). In addition, three types of responses to the Valsalva maneuver were recorded: complete cessation of flow, reversal of flow, and continuation of flow. RESULTS: The study evaluated 86 patients (63 men, 23 women) with a mean age 40.3 ± 1.5 years. Contrast venography and intravascular ultrasound imaging were used to detect venous obstructions in the inferior vena cava and the right and left iliac veins in 16.3%, 32.6%, and 80.2% of patients, respectively. When various flow parameters were evaluated, the combination of common femoral vein monophasic flow at rest and continuous flow during the Valsalva maneuver had the highest diagnostic value for iliocaval venous obstructions. The sensitivity, specificity, positive predictive value, and negative predictive value of the combination of monophasic flow at rest and unceasing forward flow during the Valsalva maneuver for the diagnosis of any degree of iliac venous obstruction were 38.1%, 100%, 100%, and 55.8%, respectively. The sensitivity and negative predictive value of these diagnostic parameters increased as the degree of obstruction increased. CONCLUSIONS: An iliocaval venous obstruction is a frequent feature of chronic venous disease. Doppler examination of the common femoral vein can be used as a screening test for iliocaval venous obstructions. The monophasic flow of the common femoral vein is a reliable diagnostic tool for the detection of possible iliac vein obstructions.

Effects of surgery on microvascular function in venous insufficiency.

BACKGROUND: The aim of our study was to assess the effects of venous stripping on microvascular functions in isolated great saphenous vein insufficiency. METHODS: Two groups of participants were prospectively evaluated. The first group included 15 healthy participants without any evidence of venous insufficiency. The second group included 20 patients with varicose veins because of great saphenous vein insufficiency. The demographics, venous clinical severity scores, and CEAP classifications of the patients were recorded. Next, all individuals underwent evaluations for microvascular vasoreactivity using an iontophoretic laser Doppler imager, and the outcomes were recorded. Patients with varicose veins underwent stripping surgeries, and microvascular vasoreactivity evaluations were repeated 6 weeks postoperatively. RESULTS: There was a statistically significant decrease in the patients with varicose veins compared with the control group in response to nitroprusside (SNP) applied at 4 mC in the supine position. Furthermore, there was also a significant difference in the response to acetylcholine (ACh) in patient group in the sitting position (P < 0.05). We also observed a statistically significant decrease in the responses to SNP applied for 1, 2, and 4 mC (P < 0.05) in the patients in the sitting position. The relief of pain and edema after surgery was found to be significant (P < 0,001). In the subgroup in which ACh was applied for 1 and 4 mC in the supine position, postoperative microvascular flow was significantly increased (P < 0.005). Moreover, based on the measurements taken in the supine position, the patients in the subgroup in which SNP was applied for 1, 2, or 4 mC exhibited significantly increased postoperative microvascular dilatation (P < 0.005). CONCLUSIONS: Saphenous vein insufficiency impairs the endothelium-dependent vasodilatation response in the perimalleolar region, and partial recoveries in microvascular function were observed after surgical treatment.

Effect of conditioning on visceral organs during indirect ischemia/reperfusion injury.

BACKGROUND: The mortality and morbidity rates of even extensive thoracoabdominal replacement have improved markedly in recent years. We investigated the effects of a temporary occlusion of the aorta as a direct precondition and temporary occlusion of the axillary artery for remote preconditioning to determine any effects that preconditioning may have on indirect (nonischemic) injuries to visceral organs (indirect effects of remote ischemia/reperfusion injury). METHODS: Thirty-seven New Zealand white rabbits were divided into five groups: controls (sham-operated; group 1); direct ischemia to the infrarenal aorta without preconditioning (group 2); direct ischemic preconditioning to the infrarenal aorta (group 3); remote ischemic preconditioning before clamping the infrarenal aorta (group 4); and simultaneous direct aortic and remote ischemic preconditioning before the clamping and during clamping of the infrarenal aorta (group 5). We used a 30-minute ischemia period for aortic occlusion for spinal cord ischemia/reperfusion. The axillary artery was used for remote preconditioning. After 24 hours, tissue specimens of the internal organs were obtained. RESULTS: Myocardial congestion was the main pathology detected in all groups. Histopathologic evaluation of tissue samples taken from the hearts showed no significant differences in terms of the degree of polymorphonuclear leukocyte (PMNL) infiltration and edema between the groups. Lung congestion and pneumonic cell infiltration were detected in all the groups. Pneumonic cell infiltration was significantly high in groups 2 and 3. Cell infiltration was lowest in group 4 at 71.4% of normal values, which differed from the normal values of 25-33.3% in the other groups (P < 0.05). Although there is a difference between the groups in case of renal congestion, there is not any difference as tubular damage and PMN. There was a significant difference with regard to renal congestion between groups 2 and 3. Renal congestion was normal in 80% of the kidneys in group 3. This differed from the normal values observed in the other groups (14.3-57.1%, P < 0.05). Liver congestion was detected in all groups. CONCLUSIONS: Different preconditioning methods may play an important role in distinct organ injuries during aortic cross-clamping. The visceral organs that exhibited positive and constructive results with direct and remote preconditioning included the lungs and kidneys during indirect ischemia/reperfusion injury. Remote ischemic conditioning was determined to be especially advantageous as a protection method, due to the fact that it is easy to use and effective for indirect ischemia/reperfusion injury.

Nutcracker syndrome manifesting with severe proteinuria: a challenging scenario in a single-kidney patient.

Nutcracker syndrome (NS) refers to compression of the left renal vein between the aorta and the superior mesenteric artery which results in left renal venous hypertension. The typical clinical presenting feature is hematuria. In this report we describe the case of patient with a single kidney who developed severe proteinuria due to NS. She was successfully treated with left renal vein transposition. This case clearly shows the relation between NS and severe proteinuria based on normal biopsy findings and the complete disappearance of proteinuria following surgery.

Long-term efficacy and safety of once-daily enoxaparin plus warfarin for the outpatient ambulatory treatment of lower-limb deep vein thrombosis in the TROMBOTEK trial.

OBJECTIVE: The present study was designed to evaluate the long-term efficacy and safety of once-daily enoxaparin plus warfarin for the outpatient ambulatory treatment of lower-limb deep venous thrombosis (DVT). METHODS: A total of 246 patients, comprising 128 men (mean age, 54.28±16.48 years) and 118 women (mean age, 50.11±16.47 years) with symptomatic lower extremity DVT, were included in this open-label, single-arm, multicenter, phase IV clinical trial conducted at 14 centers in Turkey. All patients were administered subcutaneous enoxaparin (1.5 mg/kg, once-daily) until international normalized ratio (INR) levels reached to 2 to 3, followed by oral warfarin (5 mg/d) for at least 3 months and elastic compression stockings (30-40 mm Hg). Clinical signs (leg circumference), symptoms (edema, pain, tenderness), recanalization rates upon duplex ultrasound examination, laboratory findings (D-dimer and INR levels), and postthrombotic syndrome status with CEAP classification were the efficacy parameters evaluated every 3 months during 18 months of follow-up. Safety end points included minor and major bleeding as well as serious adverse events. RESULTS: Ambulatory treatment with enoxaparin plus warfarin significantly reduced physical symptoms, including tenderness, edema, pain (P<.001), and the circumference of the affected leg (P<.001). The leg circumference difference in almost all patients was <1.5 cm at the end of 18 months (P<.001). Recanalization rates for occluded iliofemoral vein were 76.1% at 3 months and 86.5% at 18 months (P<.001). An early and significant decrease obtained in D-dimer levels on day 10 continued to decline significantly until month 6 and remained unchanged afterwards (P<.001). Of four patients diagnosed with major bleeding during oral anticoagulant use, three recovered with conservative treatment (reduction in hemoglobin levels in 2 developed at visit 2 [day 10] and intracranial bleeding in 1 developed at visit 3 [day 30]), and one patient required a hysterectomy after menorrhagia developed at visit 7 (month 18). Two of the 65 (9.9%) adverse events documented were serious adverse events, but none of the serious adverse events leading to death were related to the study medications. CONCLUSION: Ambulatory treatment with enoxaparin plus warfarin seems to be effective in symptomatic healing and in clinical improvement by reducing thrombus formation and organization at all levels of lower extremity venous system with DVT, without a significant major bleeding risk. Therefore, the results of our conventional conservative treatment are in line with 1A level evidence reported in the recent American College of Chest Physicians guideline.

Brachiobasilic versus brachiocephalic arteriovenous fistula: a prospective randomized study.

BACKGROUND: The most recent Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines recommend that the order of preference for arteriovenous fistula (AVF) placement is the radial-cephalic primary AVF, followed by the secondary brachiocephalic (BC) and, if either of these is not viable, then brachiobasilic (BB) AVF should be fashioned. However, there is limited prospective data comparing technical and clinical outcomes of these two approaches. The purpose of our study was to compare outcome, patency, and complication rates in these two autogenous upper arm AV accesses. METHODS: Between December 2003 and and January 2007, patients (61 male, 39 female) who have lost more distal AVFs were enrolled in the study. After preoperative duplex mapping, patients with patent both basilic and cephalic veins greater than 3 mm of diameter were randomized into BCAVF and BBAVF groups, each group consisting of 50 patients. All procedures were performed under local anesthesia as one-stage procedures. Follow-up data were prospectively collected. Kaplan-Meier analysis was used to calculate primary and secondary patency rates. Univariate and multivariate Cox-regression analysis was used to find risks for the occurrence of thrombosis. RESULTS: Baseline demographics, clinical characteristics, and preoperative history dialysis access were comparable between groups with the exception of the fact that mean caliber of the basilic veins were larger (4.51 +/- 0.93 mm vs 3.90 +/- 0.1 mm; P = .002). The mean duration of operation was significantly shorter in the BC group compared with the BB group (P < .001). There was no significant difference in the thirty day mortality, wound complications, 24 hour thrombosis, postoperative hemorrhage, maturation, and time to maturation between the groups. Mean follow-up was 43.2 +/- 1.8 months. Primary patency at 1 and 3 years of follow-up was 87% and 81% for the BC group and 86% and 73% for the BB group (P = .7) Secondary patency at one and three year follow-up was 87% and 70% for the BC group and 88% and 71% for the BB group, respectively (P = .8). Twenty-eight patients (28%) in the BC (18 patients) and BB (10 patients) group died with a patent fistula during the follow-up period (P = .18). Multivariate analysis revealed that use of dominant arm increased the risk of fistula failure. CONCLUSION: We conclude that brachiobasilic and brachiocephalic AVF are equally effective alternatives; however, a longer and demanding operation with BB AVF construction should be considered.

Aortoiliac occlusive disease in the presence of a horseshoe kidney: a case report.

A case of aortoiliac occlusive disease in the presence of a horseshoe kidney anomaly is presented. The importance of careful preoperative planning by way of specialized investigations is stressed and the merits of both the anterior transperitoneal and retroperitoneal approaches to aortoiliac reconstruction in the presence of a horseshoe kidney are outlined.

Simvastatin pretreatment reduces the severity of limb ischemia in an experimental diabetes model.

OBJECTIVE: The purpose of this study was to examine the effects of simvastatin pretreatment in the setting of acute limb ischemia-reperfusion injury in an experimental diabetes model that is associated with a high risk for limb loss. METHODS: Adult male Sprague-Dawley rats were randomized into two groups. Diabetes was induced in the first group by intravenous streptozotocin injection. The second group served as the nondiabetic group. Eight weeks after the streptozotocin injection, half of the rats in the diabetic and the nondiabetic groups were further randomized to receive either intraperitoneal simvastatin (1 mg/kg per day) or saline treatment for 6 weeks. Bilateral hind-limb ischemia was induced for 4 hours by the tourniquet method. After 24 hours of reperfusion, tissue samples were collected from the gastrocnemius and anterior tibial muscles bilaterally for measurement of muscle edema, percentage of necrosis, and malondialdehyde (MDA), glutathione, and myeloperoxidase (MPO) levels. RESULTS: Ischemic injury was more prominent in diabetic animals. The diabetic animals with limb ischemia exhibited a 7% increase in tissue edema, a 47% increase in muscle necrosis and MPO level, and a 15% reduction in glutathione levels compared with the nondiabetic animals (P < .05). Simvastatin treatment with 1 mg/kg for 6 weeks reduced the ischemic injury. Simvastatin pretreatment led to a 71% reduction in muscle necrosis in diabetic animals (P < .001). The protective effects of simvastatin pretreatment also correlated with a 23% improvement in tissue edema, a 75% reduction in tissue myeloperoxidase content, and a 71% increase in glutathione levels in diabetic animals (P < .01). Furthermore, skeletal muscle injury, characterized by tissue edema and leucosequestration, was significantly less severe with simvastatin pretreatment compared with the nondiabetic animals (P < .01). CONCLUSION: Simvastatin pretreatment reduced limb ischemia-reperfusion injury in diabetic and nondiabetic animals. We conclude that simvastatin pretreatment may be a potential therapeutic intervention for skeletal muscle ischemia-reperfusion injury in the clinical setting.

Use of near-infrared spectroscopy to monitor regional cerebral oxygen saturation during infrarenal aortic crossclamping in piglets.

PURPOSE: The hemodynamic changes induced by infrarenal aortic crossclamping have been well documented, but the effects of such crossclamping on cerebral perfusion are unknown. To investigate these effects, we used near-infrared spectroscopy (NIRS) to monitor regional cerebral oxygen saturation (rSO2) during infrarenal aortic crossclamping in a piglet model. METHODS: The study involved 19 piglets, each weighing 7.8 +/- 1 kg. The NIRS sensor was placed on each animal's forehead. General anesthesia was induced, and the infrarenal abdominal aorta was mobilized through a laparotomy. After heparin (1 mg/kg) was administered, crossclamps were applied proximally and distally. A 2 mm segment was resected from the proximal aortic stump, and an aorto-aortic anastomosis was performed. RESULTS: Crossclamping lasted for 30.6 +/- 6.7 min. Between the time of baseline measurement and clamp application, the rSO2 did not decrease significantly (65.4%+/- 8.9% vs. 62.4%+/- 7.8%). However, significant decreases in the rSO2 occurred between baseline measurement and clamp removal (65.4%+/- 8.9% vs. 55.7%+/- 8.9%; P<0.01), between baseline measurement and the end of surgery (65.4%+/- 8.9% vs. 57.7%+/- 7.5%; P<0.01), and between clamp application and removal (62.4%+/- 7.8% vs. 55.7%+/- 8.9%; P<0.01). At these same intervals, no intergroup differences occurred in the temperature, heart rate, or mean arterial pressure. CONCLUSION: Infrarenal aortic crossclamping significantly decreases the rSO2. NIRS, which has the advantages of being non-invasive and continuous, may be useful for monitoring this variable intraoperatively.

Proximal aortic reoperations in patients with composite valve grafts.

BACKGROUND: The purpose of this study was to examine our experience with proximal aortic reoperations in patients with composite valve grafts (CVGs) and assess postoperative survival and morbidity. METHODS: Since 1991, 33 patients with CVGs underwent reoperation for one or more of the following indications: aneurysms distal to the CVG (n = 20, 61%), false aneurysms (n = 13, 39%) and graft infection (n = 7, 21%). Operations included false aneurysm repair (n = 13, 39%), graft replacement of distal ascending aortic or transverse aortic arch aneurysm (n = 20, 61%) and aortic root re-replacement with a new CVG (n = 6, 18%) or homograft (n = 4, 12%). RESULTS: Operative mortality was 15% (n = 5), including 2 of the 7 patients who had infected CVGs (29%). All 4 patients who had infected CVGs replaced with aortic root homografts survived. Complications included vocal cord paralysis (n = 4, 12%), bleeding requiring reoperation (n = 3, 9%) and stroke (n = 2, 6%). Actuarial 3-year survival was 74.4% +/- 7.9%. CONCLUSIONS: Reoperations in patients with CVGs remain challenging procedures with high associated morbidity and mortality, especially in the setting of graft infection. The results of homograft aortic root re-replacement for infected CVGs are encouraging.

Morbidity and mortality after extent II thoracoabdominal aortic aneurysm repair.

BACKGROUND: Surgical repair of Crawford extent II thoracoabdominal aortic aneurysms (TAAAs) carries substantial risk for morbidity and mortality. The purpose of this study was to analyze the results of a large consecutive series of extent II TAAA repairs and identify factors that influence morbidity and survival. METHODS: Of 1,415 consecutive patients who underwent TAAA operations over a 13-year period, 442 (31.2%) had extent II repairs. Data from a prospectively maintained database were analyzed to determine which factors were associated with death and major complications. RESULTS: The operative mortality was 10.0% (44 patients). Postoperative complications included paraplegia/paraparesis in 33 patients (7.5%), pulmonary complications in 158 (35.7%), and renal failure in 69 (15.9%). Multivariable analysis revealed that renal insufficiency (odds ratio [OR] 2.6), increasing age (OR 1.1/year), and increasing red blood cell transfusion requirements (OR 1.1/U) were predictors for mortality; renal insufficiency (OR 2.8) and peptic ulcer disease (OR 9.3) were predictors of renal failure; and rupture (OR 6.3) was a predictor of paraplegia. Left heart bypass was an independent protective factor against paraplegia (OR 0.4). CONCLUSIONS: This contemporary experience demonstrates acceptable levels of morbidity and mortality in this high-risk group. Left heart bypass was found to provide protection against paraplegia in these patients.

Cerebrospinal fluid drainage reduces paraplegia after thoracoabdominal aortic aneurysm repair: results of a randomized clinical trial.

OBJECTIVE: Despite the use of various strategies for the prevention of spinal cord ischemia, paraplegia and paraparesis continue to occur after thoracoabdominal aortic aneurysm (TAAA) repair. Although cerebrospinal fluid drainage (CSFD) is often used as an adjunct for spinal cord protection, its benefit remains unproven. The purpose of this randomized clinical trial was to evaluate the impact of CSFD on the incidence of spinal cord injury after extensive TAAA repair. METHODS: After randomization, 145 patients underwent extent I or II TAAA repairs with a consistent strategy of moderate heparinization, permissive mild hypothermia, left heart bypass, and reattachment of patent critical intercostal arteries. The repairs were performed with CSFD (n = 76) or without CSFD (n = 69). In the former group, CSFD was initiated during the operation and continued for 48 hours after surgery. The target CSF pressure was 10 mm Hg or less. RESULTS: The two groups had similar risk factors for paraplegia. Aortic clamp time, left heart bypass time, and number of reattached intercostal arteries were also similar in both groups. Thirty-day mortality rates were 5.3% (four patients) and 2.9% (two patients) for CSFD and control groups, respectively (P =.68). Nine patients (13.0%) in the control group had paraplegia or paraparesis develop. In contrast, only two patients in the CSFD group (2.6%) had deficits develop (P =.03). No patients with CSFD had immediate paraplegia. Overall, CSFD resulted in an 80% reduction in the relative risk of postoperative deficits. CONCLUSION: Perioperative CSFD reduces the rate of paraplegia after repair of extent I and II TAAAs.

Renal perfusion during thoracoabdominal aortic operations: cold crystalloid is superior to normothermic blood.

BACKGROUND: Renal failure remains a common complication of thoracoabdominal aortic aneurysm repair. The purpose of this randomized clinical trial was to compare two methods of selective renal perfusion--cold crystalloid perfusion versus normothermic blood perfusion--and determine which technique provides the best kidney protection during thoracoabdominal aortic aneurysm repair. METHODS: Thirty randomized patients undergoing Crawford extent II thoracoabdominal aortic aneurysm repair with left heart bypass had renal artery perfusion with either 4 degrees C Ringer's lactate solution (14 patients) or normothermic blood from the bypass circuit (16 patients). Acute renal dysfunction was defined as an elevation in serum creatinine level exceeding 50% of baseline within 10 postoperative days. RESULTS: One death occurred in each group. One patient in the blood perfusion group experienced renal failure requiring hemodialysis. Ten patients (63%) in the blood perfusion group and 3 patients (21%) in the cold crystalloid perfusion group experienced acute renal dysfunction (p = 0.03). Multivariable analysis confirmed that the use of cold crystalloid perfusion was independently protective against acute renal dysfunction (p = 0.02; odds ratio, 0.133). CONCLUSIONS: When using left heart bypass during repair of extensive thoracoabdominal aortic aneurysms, selective cold crystalloid perfusion offers superior renal protection when compared with conventional normothermic blood perfusion.