Comparison of outcomes between endovascular treatment and bypass surgery in Takayasu arteritis.

OBJECTIVES: There is currently a lack of evidence regarding the optimal revascularization method for Takayasu arteritis (TA). This study compares outcomes between endovascular treatment and surgical therapy in TA patients requiring revascularization. METHOD: From September 1994 to January 2011, 235 patients were diagnosed with TA according to the diagnostic criteria of the 1990 American College of Rheumatology, and of these, arterial revascularizations were performed in 65 (27.7%). Symptomatic or angiographic recurrence and peri-operative use of immunosuppressive drugs were investigated by retrospectively reviewing medical records. RESULTS: A total of 111 arterial lesions in the 65 (27.7%) patients were revascularized during the follow-up period (median 3.2 years, range 0.01-12.7 years). At the 2-year follow-up, the symptomatic recurrence rate was significantly higher in the endovascular treatment group (32.3% vs. 11.5%, p = 0.016), as was the incidence of angiographic recurrence (32.1% vs. 11.1%, p = 0.026). The symptomatic recurrence rate was not influenced by the need for peri-operative immunosuppressive drugs (20% vs. 34.1%, p = 0.34). CONCLUSIONS: In TA patients, surgical revascularization seems to be superior to endovascular treatment with regard to patency. Further investigation to identify novel and optimal arterial revascularization methods for TA patients should be undertaken.

Consensus Document of the International Union of Angiology (IUA)-2013. Current concept on the management of arterio-venous management.

Arterio-venous malformations (AVMs) are congenital vascular malformations (CVMs) that result from birth defects involving the vessels of both arterial and venous origins, resulting in direct communications between the different size vessels or a meshwork of primitive reticular networks of dysplastic minute vessels which have failed to mature to become 'capillary' vessels termed "nidus". These lesions are defined by shunting of high velocity, low resistance flow from the arterial vasculature into the venous system in a variety of fistulous conditions. A systematic classification system developed by various groups of experts (Hamburg classification, ISSVA classification, Schobinger classification, angiographic classification of AVMs,) has resulted in a better understanding of the biology and natural history of these lesions and improved management of CVMs and AVMs. The Hamburg classification, based on the embryological differentiation between extratruncular and truncular type of lesions, allows the determination of the potential of progression and recurrence of these lesions. The majority of all AVMs are extra-truncular lesions with persistent proliferative potential, whereas truncular AVM lesions are exceedingly rare. Regardless of the type, AV shunting may ultimately result in significant anatomical, pathophysiological and hemodynamic consequences. Therefore, despite their relative rarity (10-20% of all CVMs), AVMs remain the most challenging and potentially limb or life-threatening form of vascular anomalies. The initial diagnosis and assessment may be facilitated by non- to minimally invasive investigations such as duplex ultrasound, magnetic resonance imaging (MRI), MR angiography (MRA), computerized tomography (CT) and CT angiography (CTA). Arteriography remains the diagnostic gold standard, and is required for planning subsequent treatment. A multidisciplinary team approach should be utilized to integrate surgical and non-surgical interventions for optimum care. Currently available treatments are associated with significant risk of complications and morbidity. However, an early aggressive approach to elimiate the nidus (if present) may be undertaken if the benefits exceed the risks. Trans-arterial coil embolization or ligation of feeding arteries where the nidus is left intact, are incorrect approaches and may result in proliferation of the lesion. Furthermore, such procedures would prevent future endovascular access to the lesions via the arterial route. Surgically inaccessible, infiltrating, extra-truncular AVMs can be treated with endovascular therapy as an independent modality. Among various embolo-sclerotherapy agents, ethanol sclerotherapy produces the best long term outcomes with minimum recurrence. However, this procedure requires extensive training and sufficient experience to minimize complications and associated morbidity. For the surgically accessible lesions, surgical resection may be the treatment of choice with a chance of optimal control. Preoperative sclerotherapy or embolization may supplement the subsequent surgical excision by reducing the morbidity (e.g. operative bleeding) and defining the lesion borders. Such a combined approach may provide an excellent potential for a curative result. Conclusion. AVMs are high flow congenital vascular malformations that may occur in any part of the body. The clinical presentation depends on the extent and size of the lesion and can range from an asymptomatic birthmark to congestive heart failure. Detailed investigations including duplex ultrasound, MRI/MRA and CT/CTA are required to develop an appropriate treatment plan. Appropriate management is best achieved via a multi-disciplinary approach and interventions should be undertaken by appropriately trained physicians.

First Report of Stolbur Phytoplasma Infection in Commercial Freesia hybrida Cultivars.

In January 2012, disease symptoms including chlorosis, leaf crinkle, leaf curving and stunting of whole plants, virescence, and curving and necrosis of flower stalks were observed in Freesia hybrida cvs. Evone, Honey Moon, Golden Gem, and Pallas in Icheon and Suwon (Gyeonggi Province in Korea). To determine a possible phytoplasma infection, the symptomatic freesia plants were examined for the presence of phytoplasma 16S rDNA fragment by PCR with the primer pair P1/P6 (2) and R16F1/R16R1 (in nested PCR), which amplifies phytoplasma 16S rDNA regions (4). An expected PCR product of ~1,096 bp was obtained from the symptomatic freesia plants, and they were designated as FreLN, Fre-phy-Ev4, Fre-phy-Ev6, Fre-phy-GG, Fre-phy-HM, and Fre-phy-Pal. The PCR products were sequenced and registered as GenkBank accessions AB695174 and AB709951-55. The sequence corresponding to symptomatic freesia had 98.8 to 99.4% identity with Stolbur phytoplasma strains in the 16S rDNA region, and it had only 95.7 to 96.3% identity with AY phytoplasma strains. In the ultra-thin sections of the leaf midribs, globous phytoplasmal bodies 54 to 214 nm in size were observed in sieve tube elements of phloem tissue. Fre-Phy-Ev6 and Fre-Phy-HM were doube-infected with Stolbur phytoplasma and Freesia mosaic virus (FreMV). Fre-Phy-Ev6 and Fre-Phy-HM revealed necrosis of flower stalks and flower color breaking besides curving of flower stalks. Therefore, flower color breaking and flower stalk necrosis were assumed to be caused by FreMV (1). Symptoms of chlorosis and stunting of whole plants shown in FreLN and virescence of Fre-phy-GG were typical symptoms of phytoplasmal diseases, while leaf crinkle, leaf curving, and curving of flower stalks appeared to be unique symptoms in F. hybrida. Stolbur phytoplasma was abundant in commercial freesia cultivation fields. Some of the cultivars, such as cv. Pallas, showed only curving of leaf and flower stalks without any typical symptom of phytoplasmal diseases. A phytoplasmal disease was reported in Poland in 2001 from F. hybrida exhibiting leaf chlorotic and necrotic spots, and classified as AY I-B based on RFLP analysis of PCR products (3). To our knowledge, this is the first report of Stolbur phytoplasma in F. hybrida. This result is significant because F. hybrida could be the infection source of Stolbur phytoplasma disease in floricultural crops. Interestingly, we found a prevalence of Stolbur phytoplasma in Petunia hybrida cultivars (GenBank Accession Nos. AB713757 to AB713758). High nucleotide sequence identity of 99.8% in the 16S rDNA region of Stolbur phytoplasma isolates from petunia and freesia support the inference that those Stolbur phytoplasma isolates could infect both floricultural crops. References: (1) A. A. Brunt. Freesia. Page 274 in: Virus and virus-like Diseases of Bulb and Flower Crops, John Wiley & Sons, Chichester, 1995. (2) S. Deng and C. Hiruki. J. Microbiol. Methods. 14:53, 1991. (3) M. Kaminska and H. Sliwa. Plant Dis. 85:336, 2001. (4) I. M. Lee et al. Phytopathology 84:559, 1994.

Changes in pulmonary artery pressures during ethanol sclerotherapy for arteriovenous malformations: identifying the most vulnerable period.

AIM: To evaluate the changes in pulmonary artery pressure (PAP) during ethanol embolization and to identify the most vulnerable period associated with cardiovascular collapse in patients with arteriovenous malformations (AVMs). MATERIALS AND METHODS: Twenty-three patients (30 sessions) with AVMs were enrolled. PAP was measured at the following times: baseline (T(baseline)); immediately before (T(pre)), and after (T(post)) bolus injection of absolute ethanol; at the time of maximum mean PAP value during a session (T(highest-ethanol)); 10 min after final injection (T(final)); after restoration of spontaneous breathing (T(resp)); at extubation (T(extubation)); 30 min after extubation (T(extubation-30)(min)); and at the time of maximum mean PAP after patient resumed spontaneous respiration (T(highest-resp)). Nitroglycerin was infused (range 0.5-3 µg/kg/min) in all patients to attenuate the effect of ethanol on pulmonary vasoconstriction. RESULTS: The PAPs of T(highest-ethanol), T(resp), T(extubation), and T(highest-resp) were significantly higher than the corresponding values for T(baseline) and T(final) (all p<0.05). The systolic and mean PAPs of T(highest-resp) were significantly higher than those at T(highest-ethanol) (both p<0.05). In 24 sessions (80%), the highest mean PAP was detected during the recovery period. CONCLUSION: The greatest rise in PAP was noted during the recovery period in patients undergoing ethanol embolotherapy. Therefore, PAP monitoring and nitroglycerin infusions are recommended during the recovery period because early detection of an increase in PAP and prompt management may prevent detrimental complications.

Characterization of congenital vascular malformation in the extremities using whole body blood pool scintigraphy and lymphscintigraphy.

The purpose of this study was to investigate the clinical usefulness of combined whole body blood pool scintigraphy (WBBPS) and lymphscintigraphy (LS) in the characterization of patients with congenital vascular malformations (CVMs) of the extremities. Subjects included 134 patients who underwent Tc-99m RBC WBBPS and Tc-99m filtered tin colloid (or antimony sulfur colloid) LS on initial diagnosis. Scintigraphic results were interpreted as arteriovenous malformations (AVMs), venolymphatic malformations (VLMs), lymphatic malformations (LMs), and venous malformations (VMs). Final diagnosis of the type of vascular malformation was determined by physical examination, magnetic resonance imaging (MRI), angiography, duplex ultrasonography, and/or biopsy results. The final diagnosis demonstrated that 14 of the study subjects had an AVM, 29 had a HLM, 20 had a LM, and 71 had a VM. The sensitivity of WBBPS and LS in the characterization of CVM was 85.7% (12/14) for AVMs, 96.6% (28/29) for VLMs, 95.0% (19/20) for LMs, and 88.7% (63/71) for VMs. The specificity was 100% for AVMs (120/120), 91.4% for VLMs (96/105), 99.1% for LMs (113/114), and 98.4% for VMs (62/63). The overall accuracy of WBBPS and LS was 91.0% (122/134). Our results show that combination of WBBPS with LS can characterize extremity CVMs in patients with high diagnostic accuracy, and may thus be useful for making optimal treatment decisions.

Clinical and angiographic follow-up of spontaneous isolated superior mesenteric artery dissection.

OBJECTIVES: To observe the clinical features and angiographic findings in patients with a spontaneous isolated superior mesenteric artery dissection (SISMAD) and to identify any correlation between them. METHODS: From a single institution, 32 patients (22 symptomatic patients at presentation; mean age 54years; men 97%) with SISMAD were retrospectively reviewed. All patients were available for clinical follow-up after treatment (conservative, n=28, 88%, open or endovascular superior mesenteric artery (SMA) reconstruction, n=4, 12%), and follow-up CT scans were available in 28 patients (mean 22months, range 1-80months). RESULTS: We found a positive correlation between pain severity and dissection length (p=0.03, rho=0.50, Spearman's partial correlation analysis). After conservative treatment, only one patient (3%) required bowel resection, and there was no difference in outcome between patients who were treated with anticoagulation or anti-platelet therapy and those who were not (p=1.00, Fisher's exact test). No patients had progression of their lesion on the follow-up CT angiography. CONCLUSIONS: In SISMAD patients, dissection length is positively associated with more severe clinical symptoms. After conservative treatment, we observed a benign clinical course and no CT progression of the dissection, even without anticoagulation or anti-platelet therapy. Based on our observation, patients with SISMAD can be treated conservatively without anticoagulation therapy.

Effect of proximal arterial occlusion on the progression of the distal arterial disease.

PURPOSE: To test the hypothesis that a proximal arterial occlusion has a protective effect on the progression of distal arterial disease, assessed by distal runoff resistance score (DRRS). MATERIALS AND METHODS: One hundred and nineteen patients (median age 64 y, male 96%) with a unilateral iliac and/or femoral arterial occlusion caused by atherosclerosis were analyzed retrospectively. DRRS was assessed on arteriograms of the test limb (with proximal arterial occlusion) and control limb (contralateral limb). Multivariate analysis was performed to determine if a proximal arterial occlusion was an independent risk factor for the development of a difference in the DRRS between the test and control limbs. RESULTS: The clinical features of the subjects were claudication in 85%, ankle brachial index 0.52 (median), diabetes in 30% and smoker in 76%. The upper leg DRRS of the test limb was significantly lower in the iliac occlusion group than in the control limb (1.87+/-1.69 vs 2.85+/-2.75, p=0.032). However, multivariate analysis failed to identify any risk factors associated with the difference in DRRS in both limbs. CONCLUSION: There was no evidence that a proximal arterial occlusion was associated with a slower progression of distal arterial disease.

Haemodynamic and clinical assessment of lateral marginal vein excision in patients with a predominantly venous malformation of the lower extremity.

OBJECTIVE: The purpose of the present study was to determine the effects of the surgical excision of lateral marginal veins (LMVs) in patients with a venous malformation (VM) affecting the lower extremity. METHODS: Preoperative and postoperative air plethysmography (APG), CEAP classification C scores, and venous clinical severity scores (VCSS) of the 25 VM patients who underwent LMV excision were compared. RESULTS: After LMV excision, venous haemodynamic parameters revealed significantly increased ejection fraction (EF, 33.2 S.D.18.5% vs. 39.7 S.D.21.2%, P=.020), and reduced venous volume (VV, 235.0 S.D.141.8 ml vs. 198.0 S.D.114.1 ml, P=.016) and residual venous fraction (RVF, 62.4 S.D. 26.6% vs. 56.9 S.D. 25.3%, P=.046). Clinical assessments of affected limbs revealed significantly improved mean CEAP C scores and VCSS (preoperative score, 4.4 S.D.1.7 vs. postoperative score 2.4 S.D.1.7, P=.026) after LMV excision versus preoperative data. CONCLUSION: Haemodynamic and clinical improvements were observed in patients with lower extremity VM after LMV excision.

Hepatic intra-arterial injection of 3-bromopyruvate in rabbit VX2 tumor.

PURPOSE: To evaluate the antitumoral effects of an intra-arterial injection of 3-bromopyruvate (3-BrPA) on liver VX2 tumor in rabbits. MATERIAL AND METHODS: Twenty rabbits with surgically implanted liver VX2 tumors were used. The rabbits were divided into three groups: a control, a saline, and a 3-BrPA group. Four rabbits were not treated at all, and they served as the control group. The saline group (n = 6) received only intra-arterial saline injection. The 3-BrPA group (n = 10) received an intra-arterial injection of 3-bromopyruvate through the hepatic artery. The delivered amounts of 3-bromopyruvate were as follows: 25 ml of 0.5 mM in six rabbits, 25 ml of 1.0 mM in two rabbits, and 25 ml of 2.0 mM in two rabbits. Four days after intra-arterial injection, the rabbits were sacrificed and histopathologic analysis of the explanted livers was performed with comparison of the tumor necrosis ratio (a percentage of the necrotic area versus the entire tumorous area) in each group. RESULTS: The mean tumor necrosis ratio was 12.5+/-4.2%, 44.8+/-24.7%, and 49.4+/-14.3% in the control, saline, and 3-BrPA groups, respectively. Between the control and the saline group, and between the control and the 3-BrPA group the mean tumor necrosis ratio appeared to be significantly different (P<0.05). However, there was no statistical difference in the mean tumor necrosis ratio between the saline and the 3-BrPA group (P = 0.416). CONCLUSION: A single session of intra-arterial injection of 3-BrPA showed no better results in terms of tumor necrosis than that of saline injection in a rabbit VX2 tumor model.

Surgical treatment for congenital arteriovenous malformation: 10 years' experience.

OBJECTIVES: We report our 10 years experience of the surgical treatment of congenital arteriovenous malformation (AVM). METHODS: We retrospectively reviewed the medical records of 145 patients with AVM who visited Samsung Medical Center in Korea from 1994 to 2003. Among the 145 patients, 21 patients were operated on. Preoperative embolo/sclerotherapy was done in 20 out of the 21 patients. RESULTS: The surgically treated AVMs were 13 cases of head and neck lesions, four cases of upper extremity lesions, one case each of back lesion, uterus lesion, lower extremity lesion and multiple site lesions. There were 10 patients with the extratruncular infiltrating type, nine patients with the extratruncular limited type, one patient with a truncular superficial AV fistula and one patient with a mixed type. Fourteen cases were operated on for cosmetic reasons and since they had localized lesions, and five cases were operated on for tissue necrosis. Fourteen cases were cured by a single operation, yet seven cases needed several sessions of operation to cure the AVM or to promote wound healing after surgery. CONCLUSION: The surgical treatment of AVM is a challenging issue for vascular surgeons. To minimise the complications related to surgery, a multidisciplinary team approach should be considered.

Transposition of the left renal vein in nutcracker syndrome.

Mesoaortic compression of left renal vein produces left renal vein hypertension resulting in left flank pain, hematuria and pelvic-ureteral varices. This is called the nutcracker syndrome. The nutcracker syndrome has been treated in various ways. We recently experienced two cases of patients with nutcracker syndrome. We treated the patients with transposition of their left renal vein.

Current concepts in lymphatic malformation.

A lymphatic malformation (LM) is the most common form of congenital vascular malformation (CVM). The new Hamburg classification of CVM distinguishes the truncular (T) form from the extratruncular (ET) form of LMs. Both are consequences of a developmental arrest at the different stages of lymphangiogenesis as a result of defective genes. The purpose of this review was to evaluate the current management results of both forms of LMs. A retrospective review of the clinical data of 315 patients with a diagnosis of LMs treated between September 1994 and December 2001 was performed. Lymphoscintigraphy was the most frequent diagnostic test. The patients with the ET form were treated with sclerotherapy with OK-432 and/or ethanol. Combinations of CDP (complex decongestive physiotherapy) and/or compressotherapy were used to treat all the T-form patients. In addition, surgery, either reconstructive or ablative, was offered to patients with the T form who failed to respond to the proper CDP. A multidisciplinary team performed the management of LM, and the results were evaluated every 6 months. Among 797 patients with CVM, 315 were confirmed to have LMs, either as the T form (226) or the ET form (89). Another 66 LMs were diagnosed with hemolymphatic malformations (HLM). Most of the ET forms (89/315) were the cystic type (70/89), while the T forms included aplasia and/or an obstruction (204/226). The ET form was most frequent in the head, neck, and thorax (69/89). The T form was located most frequently to the extremities (202/226), mostly to the lower limb (180/202). Two hundred and twenty-six T forms belonged to the various clinical stages: stages I-32, II-104, III-48, IV-18, and an unclear stage-24. The ET form was treated with sclerotherapy using OK-432 (108/120) and absolute ethanol (12/120). Among the 11 patients with the multiple ET form, 7 patients underwent perioperative sclerotherapy with OK-432 and a subsequent surgical excision. The clinical response of the T form at the extremity to CDP was excellent to good in a majority of clinical stages I to II (121/136) but decreased to a good to fair degree in stages III to IV (31/66). The additional surgical therapy, either reconstructive (10/19) or ablative (9/19), provided limited success in improving CDP efficacy, owing mainly to poor compliance. The long-term outcome of the initial success through self-motivated home-maintenance care during the follow-up period of up to 48 months was totally dependent on patient compliance. OK-432 sclerotherapy to 51 ET forms has shown excellent results on 88.9% of the cystic type (40/45) and 50% (3/6) of the cavernous type (minimum follow-up for 24 months). Seventeen ET forms in 7 patients were treated with a preoperative OK-432 sclerotherapy and a subsequent surgical excision, which provided good to excellent results in 14 for a minimum of 24 months. Primary lymphedema, which is the T form of LMs, can be managed safely by a combination of CDP with compressotherapy. Patients with good compliance can benefit from additional surgical therapy, either reconstructive or ablative. The ET form, particularly the cystic type, can be treated with various scleroagents that are preferably less toxic as the primary therapy. A surgical excision with or without perioperative sclerotherapy provides good results for patients with the localized cavernous type of the ET form. A multidisciplinary team approach is essential for the proper care of LM.

Management of arteriovenous malformations: a multidisciplinary approach.

BACKGROUND: Management of arteriovenous malformations (AVMs) remains challenging because of their unpredictable behavior and high recurrence rate. A multidisciplinary approach based on a new classification scheme and improved diagnostic techniques may improve their management. The purpose of this study was to review our experience with combined embolotherapy, sclerotherapy (embolo/sclerotherapy), and surgical procedures to manage AVMs. METHODS: A total of 797 patients with congenital vascular malformations (January 1995 through December 2001) was investigated with noninvasive studies. Once an AVM was diagnosed, all underwent angiographic confirmation as a roadmap for treatment. Embolo/sclerotherapy and surgical procedures were instituted by the multidisciplinary team with periodic follow-up per protocol. Seventy-six patients with AVMs were reviewed retrospectively to assess the diagnosis and management by a multidisciplinary approach. RESULTS: Seventy-six (9.5% of all CVM) patients had AVMs, mostly infiltrating, extratruncular form (61/76). Embolo/sclerotherapy with various combinations of absolute ethanol, N-butyl cyanoacrylate (NBCA), contour particles, and coils were used in 48 patients. Sixteen patients with surgically accessible localized lesions completed preoperative embolism and sclerotherapy through 24 sessions, with subsequent surgical excision with minimal morbidity. Interim results were excellent, with no evidence of recurrence in all 16 patients with a mean follow-up of 24 months. Thirty-two patients with surgically inaccessible lesions (infiltrating) were treated with embolism and sclerotherapy alone. There were nine failures in a total of 171 sessions. Interim results with a mean of 19 months' follow-up of embolism and sclerotherapy alone were excellent in the majority (25/32) and good to fair among the rest (7/32). However, 31 complications, mostly minor (27/31), occurred in 30 sessions. Four major complications occurred, including facial nerve palsy, pulmonary embolism, deep vein thrombosis, and massive necrosis of an ear cartilage. CONCLUSIONS: Diagnosis and management of AVMs by a multidisciplinary approach that integrates surgical therapy with embolism and sclerotherapy appears to improve the results and management with limited morbidity and no recurrence during early follow-up.

Advanced management of venous malformation with ethanol sclerotherapy: mid-term results.

PURPOSE: This paper is an update of previously published data on the basis of a retrospective review of midterm results of ethanol sclerotherapy on 87 patients (January 1995 to December 2000) for assessment of its efficacy as an improved treatment method for venous malformation (VM). According to this assessment, VMs were defined with a new classification and studied with advanced diagnostic technology and an advanced care system. METHODS: The average follow-up period was 24 months after completion of a multisession treatment (mean, 8.2 months). Classification of VM was based on a modification of the Hamburg classification. Advanced diagnostic technology, mostly noninvasive, was used on 226 of 520 patients with congenital vascular malformation registered at the Congenital Vascular Malformation Clinic at the Samsung Medical Center. Of the 226 patients with VM, 87 with infiltrating extratruncular lesions had a total of 399 sessions of sclerotherapy. Follow-up assessment with periodic clinical examinations by the multidisciplinary team was supplemented with body blood pool scans, duplex scans, and magnetic resonance imaging, according to protocol, once the multisession therapy was completed. Angiographic assessment was seldom included. The endpoint of this phase II study was 24 months. RESULTS: Of 399 sessions, initial success was seen in 379 sessions (95.0%) and failure was seen in 20 sessions (5%). This was mostly caused by forced abandonment from technical difficulty in delivering ethanol safely to the lesion (eg, direct drainage of VM into normal deep vein system). Later results after completion of the multisession therapy with a minimum follow-up of 24 months on 71 VMs have shown no evidence of recurrence. Eighty-seven patients have shown the same results without recurrence on an average of 18.2 months of follow-up. Fifty-one minor to major complications, mostly skin damage, developed after 47 sessions among the 379 sessions (12.4% in 24/87 patients; 27.9%). However, complications resolved spontaneously or were managed successfully, except for one permanent facial nerve palsy and one peroneal nerve palsy. CONCLUSION: Absolute ethanol sclerotherapy can deliver excellent results as an independent therapy to the infiltrating type of extratruncular form of VM, which was once taboo because of prohibitively high morbidity. Absolute ethanol may be accepted as an effective treatment method because no recurrence has been observed in the relatively long-term observation period and the morbidity has been acceptable. However, it should be reserved only for individuals and centers with expertise. The morbidity involved should be clearly understood and accepted by the patient or family, and the risk of acute and chronic complications, both major or minor, should be explained to the patient. Long-term assessment of the complication's sequelae is warranted.

Development of a platform to evaluate and limit in-stent restenosis.

The objective of this work was to develop a platform to evaluate and deliver putative therapeutic agents for in-stent restenosis. Arterial stenting is applied in more than 60% of balloon angioplasties for treating cardiovascular disease. However, stented arteries encounter accelerated rates of restenosis. No prior platform has allowed evaluation or local management of in-stent restenosis without perturbing the very system being examined. A stainless steel, balloon-expandable stent was modified to serve as an ablumenal drug delivery platform. Several combinations of bioerodible polymer microspheres and gels were evaluated for channel retention under in vitro flow and in vivo conditions. A stent-anchored hybrid system prevented material embolization under all conditions. Unlike prior platforms, these stents do not alter local inflammation or in-stent plaque formation relative to conventional Palmaz-Schatz stents after in vivo deployment. The system also proved sensitive enough to detect plaque reduction with an antirestenotic agent. We conclude that a platform to evaluate and deliver therapeutic agents for in-stent restenosis has been achieved.

Malignant esophagogastric junction obstruction: palliative treatment with an antireflux valve stent.

The authors assessed the efficacy of an antireflux valve stent in the palliation of malignant esophagogastric junction (EGJ) obstruction after in vitro testing of the stent. Seventeen patients with inoperable malignant EGJ obstruction were treated. Antireflux valves, made of three polyurethane leaflets, were attached to the distal part of the stent to prevent reflux. When the flow rate of normal saline was 100 mL/sec in the forward direction, the valve fully opened at a pressure of 10 mm Hg. When the flow rate of normal saline was 0.35 mL/sec in the backward direction, the valve nearly completely closed at a pressure of 10 mm Hg. Stent placement was successful in all patients without complications. The median dysphagia score decreased significantly, from 3.0 (dysphagia to liquids) to 1.0 (dysphagia to normal solid food) (P < .0005). No patients experienced reflux symptoms. There was one case of stent migration. A valve stent that can prevent major reflux is an effective device for the palliation of malignant EGJ obstruction.

Malignant obstruction of gastric outlet and duodenum: palliation with flexible covered metallic stents.

PURPOSE: To assess the usefulness of flexible covered metallic stents in the palliation of malignant obstruction of the gastric outlet and duodenum. MATERIALS AND METHODS: Twenty-four consecutive patients with malignant obstruction of the gastric outlet (n = 22) or duodenum (n = 2) underwent palliative treatment with self-expandable flexible covered metallic stents. Fourteen patients had advanced gastric carcinoma at the antrum and/or pylorus, and eight had obstruction at the anastomosis site of previous gastrojejunostomy. Complications and clinical status were investigated during the study period. RESULTS: The technical success rate was 75% (18 of 24 patients). Twenty-one stents were placed in 18 patients by using an introducer 6 (n = 7) or 8 mm (n = 14) in diameter. The mean follow-up period was 3.4 months (range, 1 week to 9 months). Symptoms improved in 12 (67%) patients after the procedure. There was no change in symptoms in five and a decrease in one. Twelve patients died during the follow-up period (mean survival, 4.3 months). The complication rate was 25% (six of 24 patients), including stent migration (n = 5) and fracture (n = 3). CONCLUSION: Flexible covered metallic stent placement can be useful for palliation in patients with malignant obstruction of the gastric outlet or duodenum.

Functional classification of swine manure management systems based on effluent and gas emission characteristics.

Gaseous emissions from swine (Sus scrofa) manure storage systems represent a concern to air quality due to the potential effects of hydrogen sulfide, ammonia, methane, and volatile organic compounds on environmental quality and human health. The lack of knowledge concerning functional aspects of swine manure management systems has been a major obstacle in the development and optimization of emission abatement technologies for these point sources. In this study, a classification system based on gas emission characteristics and effluent concentrations of total phosphorus (P) and total sulfur (S) was devised and tested on 29 swine manure management systems in Iowa, Oklahoma, and North Carolina in an effort to elucidate functional characteristics of these systems. Four swine manure management system classes were identified that differed in effluent concentrations of P and S, methane (CH4) emission rate, odor intensity, and air concentration of volatile organic compounds (VOCs). Odor intensity and the concentration of VOCs in air emitted from swine manure management systems were strongly correlated (r2 = 0.88). The concentration of VOC in air samples was highest with outdoor swine manure management systems that received a high input of volatile solids (Type 2). These systems were also shown to have the highest odor intensity levels. The emission rate for VOCs and the odor intensity associated with swine manure management systems were inversely correlated with CH4 and ammonia (NH3) emission rates. The emission rates of CH4, NH3, and VOCs were found to be dependent upon manure loading rate and were indirectly influenced by animal numbers.

Correlation of human olfactory responses to airborne concentrations of malodorous volatile organic compounds emitted from swine effluent.

Direct multicomponent analysis of malodorous volatile organic compounds (VOCs) present in ambient air samples from 29 swine (Sus scrofa) production facilities was used to develop a 19-component artificial swine odor solution that simulated olfactory properties of swine effluent. Analyses employing either a human panel consisting of 14 subjects or gas chromatography were performed on the air stream from an emission chamber to assess human olfactory responses or odorant concentration, respectively. Analysis of the olfactory responses using Fisher's LSD statistics showed that the subjects were sensitive to changes in air concentration of the VOC standard across dilutions differing by approximately 16%. The effect of chemical synergisms and antagonisms on human olfactory response magnitudes was assessed by altering the individual concentration of nine compounds in artificial swine odor over a twofold concentration range while maintaining the other 18 components at a constant concentration. A synergistic olfactory response was observed when the air concentration of acetic acid was increased relative to the concentration of other VOC odorants in the standard. An antagonistic olfactory response was observed when the air concentration of 4-ethyl phenol was increased relative to the other VOC odorants in the standard. The collective odorant responses for nine major VOCs associated with swine odor were used to develop an olfactory prediction model to estimate human odor response magnitudes to swine manure odorants through measured air concentrations of indicator VOCs. The results of this study show that direct multicomponent analysis of VOCs emitted from swine effluent can be applied toward estimating perceived odor intensity.