Rick de Graaf

Diagnosing Intracranial Aneurysms With MR Angiography: Systematic Review and Meta-Analysis

Background and Purpose— The aim of this study was to evaluate the sensitivity and specificity of MR angiography (MRA) in the diagnosis of ruptured and unruptured intracranial aneurysms. Methods— A systematic search was performed on 4 electronic databases on relevant articles that were published from January 1998 to October 2013. Inclusion criteria were met by 12 studies that compared MRA with digital subtraction angiography as reference standard. Two independent reviewers evaluated the methodological quality of the studies. Data from eligible studies were extracted and used to construct 2×2 contingency tables on a per-aneurysm level. Pooled estimates of sensitivity and specificity were calculated for all studies and subgroups of studies. Heterogeneity was tested, and risk for publication bias was assessed. Results— Included studies were of high methodological quality. Studies with larger sample size tended to have higher diagnostic performance. Most studies used time-of-flight MRA technique. Among the 960 patients assessed, 772 aneurysms were present. Heterogeneity with reference to sensitivity and specificity was moderate to high. Pooled sensitivity of MRA was 95% (95% confidence interval, 89%–98%), and pooled specificity was 89% (95% confidence interval, 80%–95%). False-negative and false-positive aneurysms detected on MRA were mainly located at the skull base and middle cerebral artery. Freehand 3-dimensional reconstructions performed by the radiologist significantly increased diagnostic performance. Studies performed on 3 Tesla showed a trend toward higher performance (P=0.054). Conclusions— Studies on diagnostic performance of MRA show high sensitivity with large variation in specificity in the detection of intracranial aneurysms.

Minimally invasive treatment of chronic iliofemoral venous occlusive disease.

BACKGROUND As one of the primary etiologies of the post-thrombotic syndrome, chronic venous occlusion is a huge burden on patient quality of life and medical costs. In this study, we evaluate the short-term and midterm results of endovenous recanalization by angioplasty and stenting in chronic iliofemoral deep venous occlusions. METHODS This is a retrospective observational study set in a tertiary medical referral center. Patients with venous claudication or C4-6 venous disease combined with duplex and magnetic resonance-confirmed iliofemoral or caval occlusion were included. Patients with recent deep vein thrombosis (<1 year) were excluded. The intervention was endovascular deep venous recanalization, followed by angioplasty and stenting. Safety and feasibility were clinically evaluated during the procedure and during follow-up. Reocclusions and other treatment failures were evaluated during a maximum follow-up of 31 months by ultrasound imaging and venography. RESULTS Seventy-five procedures were performed in 63 patients (average age, 44 years; range, 18-75 years), of whom 86% had a history of deep venous thrombosis. The mean time between the initial deep venous thrombosis and treatment with PTA and stenting was 12 years (maximum, 31 years). May-Thurner syndrome was present in 57%. Forty-two procedures were performed in the left, six in the right, and 11 in both lower extremities. The vena cava inferior was partially stented in 25 patients. An average of 2.6 stents (median, 2) were used per procedure. Primary patency was 74% after 1 year. Assisted primary and secondary patency rates were 81% and 96%, respectively, at 1 year. Secondary procedures included restenting, catheter-directed thrombolysis, endophlebectomy of the common femoral vein, and creation of an arteriovenous fistula. No clinically evident pulmonary emboli were noted. A bleeding complication occurred after six procedures and was deemed major in two. No patients died. Relief or significant improvement of symptoms of chronic venous occlusive disease was achieved in 81% of patients. CONCLUSIONS Endovenous recanalization by angioplasty and stenting of chronically occluded iliofemoral vein segments is a safe and effective treatment with good short-term results, even when treatment takes place decades after the initial deep venous thrombosis. Most reocclusions can be adequately treated by a secondary procedure.

Chlamydia pneumoniae Serology Is Associated With Thrombosis-Related but Not With Plaque-Related Microembolization During Carotid Endarterectomy

Background and Purpose— Chlamydia pneumoniae has repeatedly been associated with atherosclerotic disease. Our study was designed to clarify whether this association is based on C pneumoniae-induced transformation of a stable into an unstable atherosclerotic plaque or on stimulation of hypercoagulability leading to increased thrombotic arterial occlusions by C pneumoniae infection. Transcranial Doppler ultrasonographic monitoring of the middle cerebral artery during carotid endarterectomy offers the opportunity to study, before removal of the plaque, atherothrombotic emboli dislodging from an unstable carotid plaque (plaque-related emboli) and emboli related to (excessive) thrombus formation at the endarterectomy site after removal of the plaque and restoration of flow (thrombosis-related emboli). Methods— C pneumoniae IgA (≥1/16) and IgG (≥1/64) seropositivity was assessed in 53 patients with symptomatic carotid artery disease undergoing carotid endarterectomy. The removed carotid plaques were studied histologically to assess plaque instability. Results— Plaque- and thrombosis-related emboli were registered in 43 patients with an adequate transtemporal window. IgA seropositivity (58%) was associated significantly with thrombosis-related embolization (P =0.030) but not with plaque-related embolization or with histological plaque instability. Conclusions— C pneumoniae serology is associated with microembolization after endarterectomy and restoration of flow. Since these microemboli represent platelet aggregations and are related to cerebrovascular complications, our data suggest that C pneumoniae infection contributes to cerebrovascular events in patients with carotid artery disease through stimulation of thrombosis.

A randomised controlled trial comparing venous stenting with conservative treatment in patients with deep venous obstruction: research protocol

Introduction Deep venous obstruction (DVO) has a great impact on quality of life (QoL) comparable to angina pectoris or chronic pulmonary disease. Post-thrombotic scar formation and May-Thurner syndrome (MTS) are the most common causes of DVO. Conventional treatment of DVO focuses on reducing pain or leg swelling by use of (pain) medication and therapeutic elastic stockings. In the past, a venous bypass was offered in severe post-thrombotic cases, but this procedure showed bad clinical and patency outcomes. With the introduction of percutaneous angioplasty and dedicated venous stents new opportunities were created. Deep venous stenting has been shown to be effective in retrospective case series. However, there is no prior research in which QoL after interventional treatment is compared with QoL after conventional treatment. Currently, there is a debate about the true additional value of interventional treatment. We investigate whether those patients who are treated with stenting experience a change in short form 36 (SF-36) and the Veines-QoL/Sym questionnaires compared with conventionally treated patients. Methods and analysis This is a randomised trial comparing conservative deep venous management to interventional treatment. A total of 130 patients with post-thrombotic syndrome (PTS) or MTS, eligible for interventional percutaneous treatment, who did not have previous deep venous intervention will be included. Patients will be randomised to conservative treatment or venous stenting and stratified for the PTS or MTS subgroup. Conservative treatment consists of either one or a combination of pain medications, manual lymphatic drainage, compression stockings and regular post-thrombotic anticoagulant therapy. The primary outcome is the QoL change after 12 months compared with baseline QoL. Secondary outcomes are QoL changes at 6 weeks, clinical assessment of DVO, recurrence rate of deep venous thrombosis at 6 weeks and 12 months, and the total amount of working days lost. Intervention-specific outcomes include complications and patency. Ethics and dissemination The protocol is approved by the Medical Ethics Committee of Academisch ziekenhuis Maastricht/Universiteit Maastricht, The Netherlands (protocol number NLNL55641.068.15 / METC 161008).We aim to publish the results of this study in a peer reviewed journal and present our findings at national or international conferences. Trial registration number The study protocol was registered at www.clinicaltrials.gov (registration number: NCT03026049) on 17 January 2017.

The new immunosuppressive agent FK778 attenuates neointima formation in an experimental venous bypass graft model

Neointima formation as a result of smooth muscle cell (SMC) proliferation still contributes significantly to venous bypass graft stenosis and failure. The new immunosuppressive agent FK778 has recently been shown to exert anti-proliferative effects. We examined the inhibitory potential of FK778 on venous SMC proliferation and neointima formation in an experimental venous bypass graft model. Quiescent venous SMCs were incubated for 48 h with 10% FCS and different concentrations of FK778. SMC proliferation was measured by Ki67 immunostaining. Uridine was added to reverse FK778 induced pyrimidine synthesis blockade. The effect of FK778 treatment on neointima formation in vivo was assessed in an autologous epigastric vein-to femoral artery interposition graft model in rats. In vitro, FK778 inhibited venous SMC proliferation in a dose dependent manner. This effect was reversed by addition of uridine. In vivo, 3-week oral treatment with FK778 (15 mg/kg/d) significantly reduced neointima formation and stenosis in venous bypass grafts. We show that the immunosuppressive agent FK778 can prevent neointima formation in experimental venous bypass grafts by inhibiting venous SMC proliferation. FK778 might provide a new pharmacological therapy to limit vein graft stenosis and bypass graft failure.

Chlamydia pneumoniae aggravates vein graft intimal hyperplasia in a rat model

BackgroundAlong with angioplasty, autologus vein grafts are commonly used for artery bypass grafting in patients with advanced arterial stenosis and drug-resistant angina pectoris. Although initially a successful procedure, long-term functionality is limited due to proliferation and migration of smooth muscle cells. Like in atherosclerosis, common chronic infections caused by viruses and bacteria may contribute to this process of vein graft failure. Here we investigated the possible role of Chlamydia pneumoniae (Cpn) in the pathogenesis of venous graft failure in an experimental animal model. In 2 groups (n = 10 rats/group), an epigastric vein-to-common femoral artery interposition graft was placed. Immediately thereafter, rats were infected with Cpn (5*108 IFU) or injected with control solutions. Rats were sacrificed three weeks after surgery and the grafts were harvested for morphometrical and immunohistochemical analysis.ResultsCpn administration immediately after vein grafting resulted in a significant increase in medial cross-sectional area, wall thickness and total wall area. There were no significant differences in T-cell or macrophage influx. Likewise, although positive immunostaining for both HSP60 and CRP could be detected, no differences were found between groups. Based on the observation that the number of cells/μm2 was also not altered, we conclude that Cpn infection stimulates smooth muscle cell proliferation by hereunto unknown molecular mechanisms, resulting in a significant increase in intimal hyperplasia.ConclusionIn conclusion, in a well defined animal model we present here for the first time evidence for a role of Chlamydia pneumoniae in the process of venous graft failure.

Endovascular treatment of swing-segment stenosis in vascular access: current status and future directions

Swing-segment lesions are a fairly common reason for access failure and predispose to repeated interventions. The pathophysiology, hemodynamic circumstances and the primary intervention might all play a role in early recurrence. Mainly, percutaneous transluminal angioplasty (PTA), bare metal stenting and stent graft implantation have been performed to prolong lesion patency and access circuit patency. The available data on endovascular treatment of swing-segment lesions are scarce, heterogeneous and of poor quality. Moreover, with the continuous evolution of endovascular techniques and introduction of new devices there is a risk of increasing device-specific investigations. In the meantime, PTA is easily discarded in favor of novel stents and stent grafts. However, PTA might still have an important position in the overall treatment strategy to postpone loss of the vascular access site. However, without optimal post-interventional imaging, true PTA results remain obscure and indications for additional stent (graft) implantation unclear. Currently, it seems that different devices are utilized to prolong lesion patency rather than access circuit patency. Obviously, more randomized controlled trials and well-structured multicenter registries may be capable of determining a superior treatment modality for a specific lesion. However, it might be more accurate to identify the optimal sequence of interventions by which the lifespan of the access site is maintained as long as possible.

The value of intravascular ultrasound in the treatment of central venous obstructions in hemodialysis patients.

Introduction Digital subtraction angiography (DSA) is the gold standard in diagnosis and treatment of central venous obstructions (CVOs) in hemodialysis access. However, growing data suggest that DSA might underestimate the degree and morphology of venous outflow stenosis. This could lead to inappropriate CVO management. Intravascular ultrasound (IVUS) has been shown to identify lesion characteristics remaining obscure with angiography. With the current study we suggest IVUS as an eminent imaging modality in CVO management. Methods Twelve patients (8 male, mean age 62.4 ± 9 years) were analyzed for suspicion of symptomatic CVO. Both angiography and IVUS evaluation were performed to determine the degree of obstruction before and after PTA. Stent placement was indicated when significant residual stenosis (>50% lumen reduction) was suspected. Results Conventional plain angiography determined 8 out of 12 central venous lesions significant. Secondary signs of obstruction, i.e., collateral filling, was present in all 12 cases. After PTA, persistent significant stenosis was observed in 3 out of 12 patients. IVUS showed significant lumen reduction in all 12 cases. Additionally, IVUS showed a median cross-sectional area of 24 ± 12 mm2 before PTA and 37 ± 23 mm2 after PTA (NS). Furthermore, IVUS showed signs of intraluminal fibrotic trabeculations in 9 patients. Stenting was performed in 10 patients with >50% lumen reduction on IVUS after PTA. Conclusions Conventional angiography seems unreliable to identify all significant aspects of a central venous outflow obstruction. Additional use of IVUS might aid in the decision-making process and select the optimal treatment strategy.

Theme 4: Invasive management of (recurrent) VTE and PTS

a Jobst Vascular Institute, Toledo Hospital, Toledo, OH, USA b Department of Hematology, Oslo University Hospital, Oslo, Norway c Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz, Mainz, Germany d Department of Radiology, Maastricht University Medical Centre, Maastricht, The Netherlands e Department of Surgery, Section of Vascular Surgery, Conrad Jobst Vascular Research Laboratories, Ann Arbor, MI, USA f Department of Radiology and Interventional Radiology, VieCuri Medical Centre, Venlo, The Netherlands g Department of Venous Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands h Department of Vascular Surgery, University Hospital Aachen, Aachen, Germany

Revision techniques for failed PD catheters: outcome in a University Hospital

Purpose A disfunctioning peritoneal dialysis (PD) catheter has been reported in upto 35%. We report different salvage techniques used and its outcome. Methods We retrospectively reviewed our database on PD patients from 2009 to 2014. Operational data and data on PD catheter function were checked. Results From 2009 to 2014, we operated on 32 patients. Malfunction of their PD catheter was found in 23 patients and hernias in nine patients. Different laparoscopic techniques were used, including reposition of the catheter, fixation of the catheter, removal of adhesions and omentectomy. Of these 23 patients, 18 (78%) had a normal functioning catheter after the operation. Nine patients of the total of 32 patients had a correction of their hernia. In all cases, a non-absorbable mesh was used. Of those nine patients with a hernia, eight (89%) had a normal functioning catheter after the procedure. Conclusions The salvage of the catheter by means of a laparoscopic procedure or correction of a hernia is worthwhile and can save up to 81% of the catheters.