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Objective We retrospectively investigated the association between the imaging features of spontaneous isolated superior mesenteric artery dissection (SISMAD) accompanied by total true lumen occlusion and the clinical symptoms to identify the patients at high risk and establish personalized therapeutic options. Methods Among 261 patients with SISMAD, we selected 37 with Yun’s type III dissection; 35 patients underwent successful conservative management and 2 patients underwent exploratory laparotomy. After discharge, all patients were periodically followed up on an outpatient basis. We recorded patients’ general condition, symptoms, time until symptom relief, imaging findings and follow-up results. Results All patients experienced acute abdominal pain prior to admission, with an onset time of 29.95 ± 24.66 hours. The mean time until relief of abdominal pain in patients who received conservative treatment was 42.17 ± 38.09 hours. Correlation analysis revealed no correlation between the length of dissection or of the occluded segment and abdominal pain intensity. Pain scores were lower and time until pain relief was shorter in patients with a definite arc of Riolan (AOR) on admission than in those without an AOR. No collateral circulation was observed in the two patients who underwent exploratory laparotomy, and distal intestinal perfusion was poor in these cases. Complete and partial remodeling of the superior mesenteric artery (SMA) was observed in 6 and 16 patients, respectively at the 12-month follow-up. Although the SMA remained occluded in 12 patients, abundant collateral circulation was detected. Three patients were lost to follow-up. Conclusion This study highlights that conservative treatment should be attempted as first-line therapy in most patients with Yun’s type III SISMAD. Complete AOR can contribute to remission of clinical symptoms during the acute stage. Poor distal blood flow of occluded vessels may serve as an important indicator for identification of patients at high risk of ischemic intestinal necrosis.

Background The anatomical etiology of right iliac vein compression syndrome (RIVCS) differs from that of left iliac vein compression syndrome. This study aimed to investigate the clinical features and therapeutic characteristics of RIVCS. Methods Sixteen patients with nonthrombotic RIVCS were admitted to our hospital from May 2013 to July 2017. All patients underwent computed tomography venography (CTV) examinations of the right lower limb, which indicated that the right iliac veins were compressed by extrinsic structures. RIVCS was divided into 3 types according to the CTV findings. Stenting was conducted in patients with the appropriate indications. The superficial varicose veins in the lower limbs were simultaneously treated during endovascular treatment in a compound operating room. Antiplatelet therapy was administered after discharge. Results Most RIVCS cases were types II and III, and the most frequently compressed segments were the middle and distal parts of the iliac vein. Most stents did not require stretching into the inferior vena cava and therefore seldom affected contralateral blood flow. Fifteen patients required stenting; the diameters of the stents ranged from 10 to 16 mm. All symptoms were alleviated, and the ulcers healed postoperatively. The remaining single patient with superficial varicose veins did not have an indication for endovascular therapy. During follow-up, all patients were symptom free, and the stents showed excellent patency. Conclusions CTV is a simple, accurate, and important method for diagnosing RIVCS. Endovascular therapy is an effective therapeutic method for RIVCS. Compared with the left side, stent implantation for RIVCS is safer and has fewer effects on contralateral blood flow.

Stent implantation is the common treatment method for iliac vein (IV) occlusion. IV stents usually enter into the inferior vena cava (IVC) to partially or completely cover the contralateral IV, but it is still uncertain whether this can increase the risk of thrombosis in the contralateral IV. The purpose of this study was to investigate the effect of the stent position on the bilateral IVs patency. A total of 261 patients with symptomatic IV lesions, including 177 patients with non-thrombotic iliac vein lesions (NIVLs) and 84 patients with thrombotic iliac vein lesions (TIVLs), were implanted with IV stents between July 2007 and June 2017. The data of these patients were retrospectively studied. The follow-up time was 6-114 months, and the median time was 62 months. A total of 183 cases had stenting into the IVC for more than 5 mm. The incidence of thrombosis in the contralateral IV was only 0.55% (1/183). A total of 17 short- and long-term cumulative cases had ipsilateral thrombosis on the stent side. There was no significant difference between the incidence of patients (8.79%, 7/78) with stenting into the IVC for less than 5 mm and those with more than 5 mm (5.46%, 10/183, P = 0.287). However, in the TIVLs group, the incidence of ipsilateral thrombosis between stenting positions less than 5 mm (29.6%, 8/27) and those more than 5 mm (8.77%, 5/57) was significantly different (P = 0.022). Stent implantation for NIVLs had an excellent long-term patency rate; the primary patency rate and the assisted primary patency rate were 97.7% and 100%, respectively. The entry of IV stents into the IVC was safe and had a very low incidence of thrombosis in the contralateral vein. Stenting less into the IVC increased the incidence of thrombosis in the ipsilateral vein, especially among thrombotic cases. Treatment of NIVLs using stent implantation had a better long-term patency rate. This principle plays an important guiding role in the endovascular therapy of IV lesions.

Background The diagnosis of isolated visceral artery dissection (IVAD) has become more common with the increasing use of computed tomography angiography (CTA). We examined the presentation, treatment, and outcomes of patients with IVAD treated at our institution. Methods The records of 72 patients treated for IVAD between January 2010 and August 2014 were analyzed retrospectively. All were treated with antiplatelet or anticoagulant drugs after admission and were continued on oral aspirin for at least 1 year. Four asymptomatic and 52 symptomatic patients were managed conservatively with blood pressure control, bowel rest, fluid supplementation, and nutritional support. Two patients underwent open surgery because of hematochezia and 16 underwent endovascular bare-metal stenting. Results Symptoms gradually resolved in those treated conservatively, and favorable arterial wall remodeling was observed in 16 patients. Twenty-one stents were implanted in 16 patients with superior mesenteric artery dissection; 3 patients required overlapping stents. During follow-up (range, 3–53 months), all patients were symptom-free, and there were no recurrences. Follow-up CTA of patients who underwent endovascular stenting demonstrated satisfactory stent and true lumen patency. Conclusions IVAD is not uncommon. It occurs most frequently between the ages of 46 and 60 years and affects more men than women. A favorable outcome can be achieved in most of the patients with conservative management. Ischemic bowel necrosis is rare but requires open surgery. Endovascular bare-metal stenting is recommended when there is persistent abdominal pain, progression of the lesion, apparent stenosis of a true lumen compressed by a false lumen, or dilation of false lumen at a high risk of rupture.

Introduction: Protein-losing enteropathy and spontaneous isolated superior mesenteric artery dissection are both rare clinically. Protein-losing enteropathy due to superior mesenteric artery dissection is extremely rare. Patient concerns: A 46-year-old male with acute abdominal pain and hematochezia was diagnosed with a complete occlusion of the superior mesenteric artery because of dissection. He suffered from diarrhea and hypoproteinemia after an emergency thromboendarterectomy. Diagnoses: Based on laboratory tests and capsule endoscopy inspection, a diagnosis of protein-losing enteropathy was made. Interventions: Endovascular treatment was provided. Outcomes: After stent placement, he quickly recovered without a recurrence of symptoms. Conclusion: Protein-losing enteropathy is a serious complication of an isolated superior mesenteric artery dissection. Restoring the patency of the superior mesenteric artery is keyed for the treatment of this complication.

Background Phlegmasia cerulea dolens (PCD) is a severe complication of deep veions thrombosis, and there are several treatment methods. This study aimed to investigate the clinical efficacy of surgical thrombectomy and simultaneous iliac vein stent implantation for the treatment of PCD caused by iliac vein occlusion. Purpose This study aimed to investigate the clinical efficacy of surgical thrombectomy and simultaneous iliac vein stent implantation for the treatment of phlegmasia cerulea dolens (PCD) caused by iliac vein occlusion. Methods From February 2014 to December 2016, 5 patients with secondary PCD complicated with iliac vein occlusion were treated in our center. Thrombectomy by venous incision was performed with simultaneous iliac vein balloon dilatation and stents implantation. Efficacy and stents patency were assessed. Iliac vein occlusions were confirmed in all 5 patients by angiography after the thrombectomy. Stents implantation were performed after balloon dilatation. Three stents were implanted in 1 case of iliac vein and inferior vena cava (IVC) occlusion, whereas 1 stent was implanted in each of the other 4 cases. Results Symptoms were significantly relieved after surgery, with no complications. Patients were followed up for 6–24 months, and minor swelling of the affected limb was found in 1 case, with no thrombosis recurrence in all cases and vascular stent patency. Conclusions Thrombectomy by venous incision and simultaneous iliac vein stent implantation for the treatment of PCD caused by iliac vein occlusion can quickly relieve symptoms, is easily implemented, is associated with fewer complications, and has good midterm efficacy and a high patency rate, making this technique a good treatment method.

Background/Aims: Studies have shown that a change in endothelin receptor expression in the artery is related to pregnancy-induced hypertension (PIH). However, the mechanism underlying this change remains unclear. Methods: To test whether the distribution of endothelin receptor type-A (ETAR) and type-B (ETBR) plays an important role in PIH, a reduction of uterine perfusion pressure (RUPP) rat model was used to mimic some of the features of PIH; the resulting variable endothelin receptor expression was investigated in the media and intima of the aorta. Single vascular smooth muscle cells (VSMCs) were isolated from RUPP and normal pregnant (NP) rats to study the effect of ETAR and ETBR in smooth muscle cells. Results: Compared with NP rats, RUPP rats had a significant redistribution of ETBR expression in the intima and media, while there was no significant difference in ETAR expression between the two groups. ETBR upregulation in VSMCs enhanced cellular contraction and contributed to PIH. The TNF-α plasma levels in RUPP rats were two-fold higher than those of NP rats, which upregulated the expression of ETBR in VSMCS through the NF-κB pathways in RUPP rats. Conclusion: Redistribution of ETBR between the media and intima played an important role in the pathogenesis of PIH.

Objective: A retrograde technique through the gap between the distal stent landing zone and the iliac artery wall has been applied to treat type II endoleak after endovascular aortic aneurysm repair (EVAR). In this study, we tried to investigate its efficacy in the management of type III endoleak and intraoperative accidental events. Methods: We reported 2 complications of EVAR that were difficult to treat with conventional methods. One patient had a sustained type III endoleak after EVAR, and the right renal artery was accidentally sealed by a graft stent in the other patient during the operation. Results: Both complications were managed by the retrograde technique from the distal stent landing zone. In the first case, the endoleak was easily embolized by the retrograde catheterization technique, and in the second case, a stent was implanted in the right renal artery using the retrograde technique to restore blood flow. Conclusion: In some EVAR cases, the technique of retrograde catheterization through the distal stent-graft landing zone is feasible, safe, and easy to perform.

Objective Arteriovenous fistula (AVF) suffers from a high number of failures caused by insufficient outward remodeling and venous neointimal hyperplasia formation. The aim was to investigate the exact mechanism by which microRNA-155 (miR-155) in the outflow vein of AVF is regulated. Methods AVFs between the branch of the jugular vein and carotid artery in an end-to-end manner were created in C57BL/6 and miR-155−/− mice with a C57BL/6 background. The venous segments were harvested at day 7, 14, 21, and 28, and the AVFs were analyzed histologically and at a messenger RNA level using real-time quantitative polymerase chain reactions. The outflow vein of AVF and the normal great saphenous vein, collected from patients with chronic kidney disease and coronary artery bypass surgery, were analyzed by histologic and molecular biologic approaches. Results Venous neointimal hyperplasia is significantly alleviated in miR-155−/− mice, and the expression of several chemokines and cytokines in the vessel wall, including regulated on activation, normal T-cell expressed and secreted factor (RANTES), monocyte chemoattractant protein 1, and vascular endothelial growth factor, was inhibited. miR-155 promoted the RANTES expression of smooth muscle-like cells, which in turn facilitated cell proliferation and extracellular matrix production. Conclusions miR-155 enhances venous neointima formation through the autocrine and paracrine effects of smooth muscle-like cell-derived RANTES in a nuclear factor κB-dependent manner during the entire AVF process, especially at the advanced stage.

Objective— Smooth muscle–like cells are major cell components of transplant arteriosclerosis lesions. This study investigated the origin of the smooth muscle–like cells, the mechanisms responsible for their accumulation in the neointima, and the factors that drive these processes. Approach and Results— A murine aortic transplantation model was established by transplanting miR-155 −/− bone marrow cells into miR-155 +/+ mice. MicroRNA-155 was found to play a functional role in the transplant arteriosclerosis. Moreover, we found that the nonbone marrow–derived progenitor cells with markers of both early differentiated smooth muscles and stem cells in the allograft adventitia were smooth muscle progenitor cells. Purified smooth muscle progenitor cells expressed a mature smooth muscle cell marker when induced by platelet-derived growth factor-BB in vitro. In vivo, these cells could migrate into the intima from the adventitia and could contribute to the neointimal hyperplasia. The loss of microRNA-155 in bone marrow–derived cells decreased the concentration gradient of monocyte chemoattractant protein 1 between the intima and the adventitia of the allografts, which reduced the migration of smooth muscle progenitor cells from the adventitia into the neointima. Conclusions— This study demonstrated that microRNA-155 promoted the directional migration of smooth muscle progenitor cells from the adventitia by regulating the monocyte chemoattractant protein 1 concentration gradient, which aggravated transplant arteriosclerosis.

Objectives: Stent implantation is frequently used to treat iliac vein occlusion. However, the recommended extension of the stent mesh into the inferior vena cava (IVC) may affect blood flow through the contralateral iliac vein. We analyzed the influence of iliac vein stent extension on contralateral iliac vein patency and neointima formation in a dog surgery model. Methods: Bare stents were implanted into the left iliac veins of 12 beagles with the proximal end covering the opening of the contralateral iliac vein. Blood flow was measured by color Doppler 4, 8, and 12 weeks postoperation. At each measurement point, a subgroup was killed, and the stents and veins were removed for pathological examination. Results: Stents were successfully implanted, and there was no immediate stent occlusion or iliac vein thrombus by color Doppler examinations. Contralateral blood flow was maintained with no obvious abnormalities for 12 weeks. Neointima formed and advanced toward the center of the stent, but small coverage of the contralateral iliac vein opening did not change significantly with time postoperation (9.33% ± 1.54% at 4 weeks, 10.65% ± 1.01% at 8 weeks, and 10.92% ± 1.30% at 12 weeks; P > .05). Scanning electron microscopy showed neointima covering the surface of stent wires at the opening of the contralateral iliac vein, which did increase with time: 63.58% ± 12.39% at 4 weeks, 97.13% ± 2.71% at 8 weeks ( P < .001 vs 4 weeks), and 99.63% ± 0.60% after 12 weeks ( P > .05 vs 8 weeks; P < .001 vs 4 weeks). The neointimal coverage rate of the meshes increased obviously with time. However, no neointima was found forming a mesh between stent wires. Conclusion: Although there was intimal hyperplasia on the rim of the bare stent in the IVC, expansion was limited and did not block the opening of the contralateral iliac vein. The stent had no obvious influence on blood backflow in the contralateral iliac vein.

Objective: To summarize the reproducible experience obtained during the treatment of superior mesenteric artery dissection (SMAD) and to investigate the therapeutic options for this condition. Methods: The clinical data from 10 patients with SMAD were retrospectively analyzed, including 6 patients receiving conservative therapy, 2 patients receiving endovascular stenting, 1 patient receiving dissecting aneurysm resection plus vascular prosthesis grafting, and 1 patient receiving thrombectomy plus intimectomy. Results: For the 6 patients subjected to the conservative therapy, the symptoms were thoroughly under control without relapse during the follow-up; for the 2 patients receiving endovascular stenting, the computed tomography (CT) examination performed during the follow-up demonstrated a patent true lumen and an occluded false lumen; for the patient with dissecting aneurysm resection plus vascular prosthesis grafting, a short dissection was observed at the distal end of the vascular prosthesis but without progression during the 14-month follow-up period; for the patient with thrombectomy plus intimectomy, postoperatively, the patient experienced diarrhea, body weight loss, and hypoproteinemia, and CT scanning demonstrated segmental SMA occlusions, which were not fully remitted by conservative therapy until the application of endovascular stenting 4 months later. Conclusions: The therapeutic regimen for isolated SMAD should be established based on the clinical symptoms of the patient and the hemodynamic status in SMA. The conservative therapy is mainly indicated for the asymptomatic patients or those with short-term symptoms, while the endovascular or surgical therapy should be recommended for those with persistent intestinal ischemia-related symptoms, rupture of artery, and/or obvious aneurysmal false lumen dilation at a high risk of rupture.