Pulmonary arteriovenous malformations in patients with previous brain abscess: a cross-sectional population-based study.

BACKGROUND AND PURPOSE: Pulmonary arteriovenous malformations (PAVMs) may cause recurrent brain abscess. The primary aim was to determine the prevalence of PAVM amongst survivors of brain abscess. The proportion with cardiac right-to-left shunts was also assessed post hoc. METHODS: This was a cross-sectional population-based study of adult (≥18 years) survivors of cryptogenic bacterial brain abscess in Denmark from 2007 through 2016. Patients were invited for bubble-echocardiography to detect vascular right-to-left shunting and, if abnormal, subsequent computed tomography thorax for diagnosis of PAVM. Data are presented as n/N (%) or median with interquartile range (IQR). RESULTS: Study participation was accepted by 47/157 (30%) eligible patients amongst whom two did not appear for scheduled bubble-echocardiography. The median age of participants was 54 years (IQR 45-62) and 19/57 (33%) were females compared with 59 years (IQR 48-68, p = 0.05) and 41/85 females (48%, p = 0.22) in non-participants. Bubble-echocardiography was suggestive of shunt in 10/45 (22%) participants and PAVM was subsequently confirmed by computed tomography in one patient with grade 1 shunting. The corresponding prevalence of PAVM was 2% (95% confidence interval 0.06-11.8) amongst all examined participants. Another 9/45 (20%) were diagnosed with patent in persistent foramen ovale (n = 8) or atrial septum defect (n = 1), which is comparable with the overall prevalence of 25% amongst adults in the Danish background population. CONCLUSIONS: Undiagnosed PAVM amongst adult survivors of cryptogenic bacterial brain abscess is rare but may be considered in select patients. The prevalence of cardiac right-to-left shunts amongst brain abscess patients corresponds to the prevalence in the general population.

Transarterial Embolization of Simple Pulmonary Arteriovenous Malformations: Long-Term Outcomes of 0.018-Inch Coils versus Vascular Plugs.

PURPOSE: To compare the safety, effectiveness, and persistence rates of 0.018-inch coils with those of Amplatzer vascular plugs (AVPs; Abbott Vascular, Abbott Park, Illinois) for the treatment of pulmonary arteriovenous malformations (PAVMs) in response to a growing concern that 0.018-inch coil embolization would increase the long-term persistence rate. MATERIALS AND METHODS: This is a retrospective, single-center study of a database (2002-2020) of 633 PAVM embolizations. Complex PAVMs and those not embolized with 0.018-inch coils or plugs were excluded. PAVM embolization material was classified into 4 groups: (a) 0.018-inch nonfibered coils (NFCs), (b) 0.018-inch fibered coils (FCs), (c) NFCs and FCs, or (d) plugs. Persistence was defined as flow through the PAVM on digital subtraction angiography (DSA) or as <30% diameter reduction of the aneurysmal sac on unenhanced computed tomography (CT). Kaplan-Meier analysis and Cox regression were used to assess PAVM's persistence-free survival. RESULTS: A total of 312 PAVM embolizations with NFCs (43 PAVMs), FCs (127 PAVMs), NFCs and FCs (12 PAVMs), or plugs (130 PAVMs) in 109 patients (28% men; mean age = 49 years) were included. All PAVM embolizations were technically successful without any major adverse events. PAVM persistence-free survival rates at 10 years' follow-up were 40.8% versus 44.7% in the NFC and FC groups (P = .22) and 47.3% versus 81.0% in the 0.018-inch coil (NFC or FC) and plug groups (P < .0001), respectively. There were 0.43 (79/182) and 0.08 (10/130) re-embolization procedures per PAVM in the 0.018-inch coil and plug groups, respectively (P < .001). CONCLUSIONS: PAVM embolization with 0.018-inch coils was safe, but persistence rate with PAVM embolization was significantly higher than that with plugs, with no significant differences between FCs and NFCs.

Repair of Isthmocele Following Embolization of Uterine Arteriovenous Malformation.

OBJECTIVE: To present a case of concurrent uterine arteriovenous malformation (AVM) and isthmocele, treated with ethylene vinyl alcohol copolymer (EVAC) embolization of the AVM followed by robotic isthmocele repair. DESIGN: A stepwise video demonstration with narration. SETTING: A tertiary care academic hospital. Patient is a 37-year-old with one previous cesarean section who presented with persistent heavy vaginal bleeding after a dilation and evacuation procedure. Imaging showed evidence of an isthmocele and an iatrogenic uterine AVM secondary to the dilation and evacuation procedure. Both entities are morbid conditions associated with significant operative blood loss. Embolization of the acquired AVM was first performed to stabilize bleeding. In addition, owing to the extensive uterine defect and history of infertility, surgical repair of the isthmocele was recommended. INTERVENTIONS: A multidisciplinary approach combining interventional radiology and gynecologic surgery expertise, implementing several strategies to minimize blood loss: 1. Image-guided uterine AVM embolization with EVAC [1] 2. Hysteroscopic identification of isthmocele and residual EVAC in the cavity, with fluorescence transillumination to clearly delineate isthmocele borders 3. Robot-assisted laparoscopic approach for bladder flap creation, as well as retroperitoneal space dissection to skeletonize uterine arteries 4. Transient occlusion of uterine arteries using vascular clamps to minimize operative blood loss given the isthmocele size and its proximity to the left uterine artery 5. Resection of the isthmocele and removal of residual intracavitary EVAC 6. Multilayer, bidirectional hysterotomy closure and vascular clamp removal to restore uterine blood supply CONCLUSIONS: Successful multidisciplinary treatment of concurrent uterine AVM and isthmocele. Cesarean delivery at 36 to 37 weeks' gestational age was recommended for future deliveries.

Predictors of heart failure symptoms in hereditary hemorrhagic telangiectasia patients with hepatic arteriovenous malformations.

BACKGROUND: Hepatic arteriovenous malformations (AVMs) in hereditary hemorrhagic telangiectasia (HHT) patients are most commonly hepatic artery to hepatic venous shunts which can result in high-output heart failure. This condition can be debilitating and is a leading cause of liver transplantation in HHT patients. However, it is not known what characteristics can discriminate between asymptomatic patients and those who will develop heart failure symptoms. RESULTS: 176 patients with HHT were evaluated with computed tomography angiography (CTA) between April 2004 and February 2019 at our HHT Center of Excellence. 63/176 (35.8%) patients were found to have hepatic AVMs on CTA. 18 of these patients were excluded because of the presence of another condition which could confound evaluation of heart failure symptoms. In the remaining 45 patients included in our cohort, 25/45 (55.6%) patients were classified as asymptomatic and 20/45 (44.4%) were classified as symptomatic, and these groups were compared. In symptomatic patients, mean common hepatic artery (CHA) diameter was significantly higher (11.1 versus 8.4 mm) and mean hemoglobin levels were significantly lower (10.7 vs 12.6 g/dL). A stepwise multiple logistic regression analysis demonstrated that both CHA diameter and hemoglobin level were independent predictors of heart failure symptoms with ORs of 2.554 (95% CI 1.372-4.754) and 0.489 (95% CI 0.299-0.799), respectively. The receiver operator characteristic (ROC) curve of our analysis demonstrated an AUC of 0.906 (95% CI 0.816-0.996), sensitivity 80.0% (95% CI 55.7-93.4%), and specificity 75.0% (95% CI 52.9-89.4%). CONCLUSIONS: CTA is an effective and easily reproducible method to evaluate hepatic involvement of HHT. Utilizing CTA, clinical, and laboratory data we determined CHA diameter and hemoglobin level were independent predictors of heart failure symptoms.

Resection of Clustered Arteriovenous Malformations to Avoid Lung Transplantation.

A 54-year-old man with hereditary hemorrhagic telangiectasia and severe hypoxemia was referred for lung transplantation. Embolization had not been performed because of numerous bilateral small pulmonary arteriovenous malformations. Although he appeared to be qualified for lung transplantation, we instead performed bilateral thoracoscopic multiple wide wedge resections because of his age, lifestyle as a farmer, and relatively clustered distribution of arteriovenous malformations. Intermittent bilateral ventilation was needed because of poor oxygenation in the early stages of the operation, but his oxygenation improved as the resection progressed. His postoperative oxygenation improved significantly, and lung transplantation was avoided.

Unique case of a post-traumatic nasoseptal arteriovenous malformation.

Extracranial manifestation of arteriovenous malformations (AVMs) is uncommon. Nasoseptal AVMs are an even rarer entity. In this case report, we present an interesting and first-of-its-kind case of the development of a left nasoseptal AVM in a 60-year-old man after a fall. This was likely post-traumatic, unlike the usual congenital AVMs described in the literature. The patient was managed conservatively with regular follow-up for the AVM as he was asymptomatic.

Successful transcatheter arterial embolization for massive hemorrhage from acquired uterine arteriovenous malformation which occurred as a complication of hysterectomy: A case report.

RATIONALE: Uterine arteriovenous malformation (UVM), which can be congenital or acquired, is a relatively rare disorder that can cause life-threatening hemorrhage. Acquired UVM occurs predominantly after previous uterine procedures; rarely, it may occur after a hysterectomy. Although the best treatment option for UVM remains controversial, transcatheter arterial embolization (TAE) has recently been introduced as a safe and effective treatment. PATIENT CONCERNS: A 34-year-old woman who underwent hysterectomy for uncontrolled postpartum bleeding continued to have hemoperitoneum. DIAGNOSIS: Two days after surgery, massive hemoperitoneum was identified on computed tomography scan, and acquired UVM was diagnosed by angiography. INTERVENTIONS: The patient was successfully treated using TAE with an n-Butyl cyanoacrylate. OUTCOMES: After embolization, hemodynamic stability was achieved. A day after embolization, hemoglobin was 10.2 g/dL, and the patient was discharged from the hospital 4 days thereafter. LESSONS: Although the overall incidence of acquired UVM after hysterectomy is low, bleeding from acquired UVM should be considered as one of the differential diagnoses in the immediate postpartum period, especially when the clinical symptoms do not correlate with the amount of blood loss. A high index of suspicion, prompt diagnosis and intervention, and a multidisciplinary approach in the management were the elements of a successful outcome in this case.

Angiotensin II antagonists and gastrointestinal bleeding in left ventricular assist devices: A systematic review and meta-analysis.

Gastrointestinal bleeding (GIB) especially from arteriovenous malformations (AVM) remains one of the devastating complications following continuous-flow left ventricular device (CF-LVAD) implantation. Blockade of angiotensin II pathway using angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) was reported to mitigate the risk of GIB and AVM-related GIB by suppressing angiogenesis. We performed a systematic review and meta-analysis to evaluate the association between ACEI/ARB treatment and GIB in CF-LVAD population. Comprehensive literature search was performed through December 2019. We included studies reporting risk of GIB and/or AVM-related GIB events in LVAD patients who received ACEI/ARB with those who did not. Data from each study were combined using the random-effects to calculate odd ratios and 95% confidence intervals. Three retrospective cohort studies were included in this meta-analysis involving 619 LVADs patients (467 patients receiving ACEI/ARB). The use of ACEI/ARB was statistically associated with decreased incidence of overall GIB (pooled OR 0.35, 95% CI 0.22-0.56, I2 = 0.0%, p < 0.001). There was a non-significant trend toward lower risk for AVM-related GIB in patients who received ACEI/ARB (pooled OR 0.46, 95% CI 0.19-1.07, I2 = 51%, p = 0.07). Larger studies with specific definitions of ACEI/ARB use and GIB are warranted to accurately determine the potential non-hemodynamic benefits of ACEI/ARB in CF-LVAD patients.

Deficiency of Notch signaling in pericytes results in arteriovenous malformations.

Arteriovenous malformations (AVMs) are high-flow lesions directly connecting arteries and veins. In the brain, AVM rupture can cause seizures, stroke, and death. Patients with AVMs exhibit reduced coverage of the vessels by pericytes, the mural cells of microvascular capillaries; however, the mechanism underlying this pericyte reduction and its association with AVM pathogenesis remains unknown. Notch signaling has been proposed to regulate critical pericyte functions. We hypothesized that Notch signaling in pericytes is crucial to maintain pericyte homeostasis and prevent AVM formation. We inhibited Notch signaling specifically in perivascular cells and analyzed the vasculature of these mice. The retinal vessels of mice with deficient perivascular Notch signaling developed severe AVMs, together with a significant reduction in pericytes and vascular smooth muscle cells (vSMC) in the arteries, while vSMCs were increased in the veins. Vascular malformations and pericyte loss were also observed in the forebrain of embryonic mice deficient for perivascular Notch signaling. Moreover, the loss of Notch signaling in pericytes downregulated Pdgfrb levels and increased pericyte apoptosis, pointing to a critical role for Notch in pericyte survival. Overall, our findings reveal a mechanism of AVM formation and highlight the Notch signaling pathway as an essential mediator in this process.

Intermixed arteriovenous malformation and hemangioblastoma: case report and literature review.

We report the third presentation of an intermixed arteriovenous malformation and hemangioblastoma. The rare occurrence of the diagnostic histologic features of both a neoplasm and vascular malformation in a single lesion is more common in gliomas, as angioglioma, and is termed an 'intermixed' lesion. We review the literature concerning the developmental biology of each lesion, and potential interplay in the formation of an intermixed vascular neoplasm and vascular malformation. The roles of cellular origin, genetic susceptibility, favourable microenvironment, altered local gene expression and key regulatory pathways are reviewed. Our review supports angiography and genetic profiling in intermixed lesions to inform management strategies. Consideration should be given to multimodality therapeutic interventions as required, including microsurgical resection, stereotactic radiosurgery and further research to exploit emerging molecular targets.

Update on extracranial arteriovenous malformations: A staged multidisciplinary approach.

Arteriovenous malformations (AVMs) are vascular lesions that are thought to arise from congenital errors during development of vessels resulting in abnormal connections between arteries and veins. Though most AVMs develop in the brain or spinal cord, they can occur anywhere in the body. These extracranial or peripheral AVMs have a predilection for the head, neck, and limbs. Since these malformations infiltrate normal soft tissue, management requires selective treatment with preservation of normal surrounding architecture. Therefore, they are best addressed through a staged multimodal and multidisciplinary approach, using a combination of different laser, interstitial, intravascular and surgical techniques to specifically target anomalous vessels. The goal of treatment is overall disease improvement and symptom control with interventions that do not result in outcomes worse than the disease itself. Recently, the discovery of somatic and germline mutations in peripheral AVMs have contributed to a better understanding of the pathophysiology, resulting in promising new pharmacologic treatments. Recent evidence suggests that adjuvant medical therapy can enhance and sustain interventional and/or surgical outcomes. Herein we describe how a new understanding of the etiology and physiology of extracranial AVM provides guidance to current treatment approaches.

Second International Guidelines for the Diagnosis and Management of Hereditary Hemorrhagic Telangiectasia.

DESCRIPTION: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease with an estimated prevalence of 1 in 5000 that is characterized by the presence of vascular malformations (VMs). These result in chronic bleeding, acute hemorrhage, and complications from shunting through VMs. The goal of the Second International HHT Guidelines process was to develop evidence-based consensus guidelines for the management and prevention of HHT-related symptoms and complications. METHODS: The guidelines were developed using the AGREE II (Appraisal of Guidelines for Research and Evaluation II) framework and GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology. The guidelines expert panel included expert physicians (clinical and genetic) in HHT from 15 countries, guidelines methodologists, health care workers, health care administrators, patient advocacy representatives, and persons with HHT. During the preconference process, the expert panel generated clinically relevant questions in 6 priority topic areas. A systematic literature search was done in June 2019, and articles meeting a priori criteria were included to generate evidence tables, which were used as the basis for recommendation development. The expert panel subsequently convened during a guidelines conference to conduct a structured consensus process, during which recommendations reaching at least 80% consensus were discussed and approved. RECOMMENDATIONS: The expert panel generated and approved 6 new recommendations for each of the following 6 priority topic areas: epistaxis, gastrointestinal bleeding, anemia and iron deficiency, liver VMs, pediatric care, and pregnancy and delivery (36 total). The recommendations highlight new evidence in existing topics from the first International HHT Guidelines and provide guidance in 3 new areas: anemia, pediatrics, and pregnancy and delivery. These recommendations should facilitate implementation of key components of HHT care into clinical practice.

[Case report of hereditary hemorrhagic telangiectasia in children and literature review].

Objective: To analyze the clinical features of 2 children with hereditary hemorrhagic telangiectasia (HHT) and review relevant literature. Methods: The clinical data of 2 children with HHT who were admitted to Beijing Children's Hospital, Capital Medical University from February 2017 to June 2018 were retrospectively analyzed. Meanwhile, the relevant papers published before December 2019 in Wanfang and Pubmed database were searched with the key words of "hereditary hemorrhagic telangiectasia" in Chinese and English, and reviewed. Results: The first case was an 11-year-old boy, presented with fever and cough for 6 days. His past history revealed 3 times of left pneumonia and mild epistaxis. Ultrasound of the chest soft tissue found hemangioma and vascular malformation. Enhanced CT with vascular reconstruction suggested pulmonary arteriovenous malformation and multiple arteriovenous fistulas in the liver. After being treated with interventional pulmonary arteriovenous fistula embolization, his condition improved. The second case was a 12-year-old girl, presented with iron deficiency anemia during the past 3 years. Endoscopic resection of polyps had been performed before due to multiple polyps in the colon. High-resolution lung CT revealed multiple ground-glass nodules in bilateral lungs. Ultrasound of the digestive tract suggested small intestine polyps and secondary chronic loose intussusception. After admission, small bowel intussusception reduction was performed, and the polyps were ligated. Her whole exon gene testing suggested SMAD4 heterozygous variation. In the large number of reported cases, HHT1 and HHT2 are the main type. Conclusions: Children with HHT may present with anemia and repeated intestinal polyps. It is worth noting that visceral arteriovenous malformations, such as pulmonary arteriovenous malformations, which is easily misdiagnosed as recurrent pneumonia, can also occur in children with HHT. Enhanced CT with vascular reconstruction can help find pulmonary arteriovenous malformation, and timely genetic test can confirm the diagnosis.

[Brain abscess and Osler-Weber-Rendu syndrome: Do not forget to look for pulmonary arteriovenous malformations]. / Abcès cérébral et maladie de Rendu-Osler-Weber : pensez à rechercher des malformations artério-veineuses pulmonaires.

INTRODUCTION: Osler-Rendu-Weber syndrome or hereditary hemorrhagic telangiectasia affects between 1/5000 and 1/8000 people. It is characterized by presence of recurrent epistaxis, mucocutaneous telangiectasia and visceral arteriovenous malformations. It is a genetic disease with autosomal dominant transmission inducing an endothelial cells hyper-proliferation. CASE REPORT: A 68-year-old women with Osler-Rendu-Weber syndrome was referred for management of general impairment with confusional syndrome and hyperthermia. Various examinations have allowed us to conclude at diagnosis of brain abscess with ventriculitis probably favored by right-left shunt secondary to pulmonary arteriovenous malformations. Evolution was favorable after antibiotic treatment and endovascular embolization. CONCLUSION: In case of brain abscess without obvious promoting factor, don't forget to looking for a right-left shunt providing septic or aseptic emboli. Furthermore, diagnosis of Rendu-Osler-Weber syndrome should be considered presence of telangiectasias and/or epistaxis.

Treatment of gastrointestinal bleeding in left ventricular assist devices: A comprehensive review.

Left ventricular assist devices (LVAD) are increasingly become common as life prolonging therapy in patients with advanced heart failure. Current devices are now used as definitive treatment in some patients given the improved durability of continuous flow pumps. Unfortunately, continuous flow LVADs are fraught with complications such as gastrointestinal (GI) bleeding that are primarily attributed to the formation of arteriovenous malformations. With frequent GI bleeding, antiplatelet and anticoagulation therapies are usually discontinued increasing the risk of life-threatening events. Small bowel bleeds account for 15% as the source and patients often undergo multiple endoscopic procedures. Treatment strategies include resuscitative measures and endoscopic therapies. Medical treatment is with octreotide. Novel treatment options include thalidomide, angiotensin converting enzyme inhibitors/angiotensin II receptor blockers, estrogen-based hormonal therapies, doxycycline, desmopressin and bevacizumab. Current research has explored the mechanism of frequent GI bleeds in this population, including destruction of von Willebrand factor, upregulation of tissue factor, vascular endothelial growth factor, tumor necrosis factor-α, tumor growth factor-ß, and angiopoetin-2, and downregulation of angiopoetin-1. In addition, healthcare resource utilization is only increasing in this patient population with higher admissions, readmissions, blood product utilization, and endoscopy. While some of the novel endoscopic and medical therapies for LVAD bleeds are still in their development stages, these tools will yet be crucial as the number of LVAD placements will likely only increase in the coming years.

A Proposed Classification of Intraretinal Microvascular Abnormalities in Diabetic Retinopathy Following Panretinal Photocoagulation.

Purpose: To investigate the characteristics of intraretinal microvascular abnormalities (IRMAs) before and after panretinal photocoagulation (PRP) for diabetic retinopathy (DR) by using optical coherence tomography angiography (OCTA). Methods: Forty-six eyes of 29 patients with DR were included (26 eyes with severe nonproliferative diabetic retinopathy [SNPDR] and 20 eyes with proliferative diabetic retinopathy [PDR]). En face OCTA images of IRMAs in a 6 × 6-mm area were acquired by using Cirrus 5000 with AngioPlex. The morphological changes in IRMAs were evaluated before and after PRP. The changes in the IRMAs were divided into five subtypes: unchanged; tuft regression; reperfusion; mixed (combined tuft regression/reperfusion); and worsening (new appearance of tuft). Results: Unchanged IRMAs were identified in 15 SNPDR eyes and 2 PDR eyes; all neovascularization (NV) had regressed after PRP. Tufts were more frequently observed in the PDR eyes (15/20, 75%) than in the SNPDR eyes (8/26, 31%) (P = 0.003), and two tufts tended to exceed the inner limiting membrane, which showed progression to NV before PRP. The reperfusion phenomenon was observed in 7/26 SNPDR eyes and 4/20 PDR eyes, including the mixed type, and showed two vascular patterns: abnormal (dilated, tortuous, and twisted) and normal vessels. The worsening type was observed in 1/26 SNPDR eye and 2/20 PDR eyes. Conclusions: OCTA enabled classification of IRMA into more detailed types. The unchanged and reperfusion types suggested that IRMAs had aspects of remodeling. However, IRMAs with tufts were observed in 75% of the PDR eyes, and the tufts had aspects of NV.