Circulating Interleukin-6 and CD16 positive monocytes increase following angioplasty of an arteriovenous fistula.

Arteriovenous fistulas are the ideal form of vascular access that allows provision of haemodialysis. Stenotic lesions caused by neointimal hyperplasia commonly occur resulting in patients requiring a fistuloplasty. This is effective but there is a high recurrence rate. We sought to investigate the effects of a fistuloplasty on monocyte populations. Blood samples were taken from patients before and after their fistuloplasty procedure. Samples were analysed using flow cytometry, ELISA and Luminex assays. Univariate cox regression was carried out to investigate associations with post fistuloplasty patency. At 1-2 days post fistuloplasty, the proportion of classical (CD14++CD16-) monocytes decreased (p < 0.001), whilst intermediate (CD14++CD16+) and non-classical (CD14+CD16+) monocytes increased (both p < 0.01) in a cohort of 20 patients. A time course study carried out in 5 patients showed that this was due to an increase in absolute numbers of non-classical and intermediate monocytes. Higher levels of non-classical monocytes pre-fistuloplasty were associated with an increased risk for patency loss (p < 0.05). We measured 41 soluble factors in plasma samples taken before a fistuloplasty in 54 patients, with paired post-fistuloplasty samples (1-2 days) available in 30 patients. After correcting for false discovery, the only factor with a significant change in level was IL-6 (P = 0.0003, q = 0.0124). In a further time-course study in 6 patients, peak level of IL-6 occurred 2-3 h post fistuloplasty. This study demonstrates that there is a systemic inflammatory response to the fistuloplasty procedure and that monocyte subsets and IL-6 may be important in the pathophysiology of restenosis.

Association of early failure of arteriovenous fistula with mortality in hemodialysis patients.

Arteriovenous fistula (AVF) is prone to early dysfunction and relates to poor outcome. However, little is known about the role of early AVF dysfunction as an independent risk factor for death in hemodialysis patients. A retrospective cohort study was performed using data of patients who underwent initial AVF surgery at a single institution. Demographic, clinical, biochemistry and AVF parameters were extracted from the electronic records, and the association between these variables and mortality was analyzed by Cox proportional hazards model. A total of 501 patients on hemodialysis (63.4 ± 12.7 years, 57.3% male) were included, and the median observation period was 3.66 years. In multivariate analysis, early failure of AVF (hazard ratio (95% confidence interval): 1.54 (1.06-2.24); p = 0.023) was associated with overall mortality but not cardiovascular mortality. Other identified predictors of overall mortality included older age, peripheral artery disease (PAD), cardiomegaly, higher white blood cell (WBC) count and corrected calcium level, and lower total cholesterol level, while predictors of cardiovascular mortality included older age, coronary artery disease (CAD), PAD and lower hemoglobin level. In conclusion, patients with early AVF failure were associated with increased risk of overall mortality.

Morbidity and mortality associated with sequential flow reduction embolization technique of cerebral arteriovenous malformations using n-butyl cyanoacrylate.

BACKGROUND: Endovascular embolization of cerebral arteriovenous malformations (AVM) with liquid n-butyl cyanoacrylate (n-BCA) serves multiple purposes including AVM occlusion and flow reduction in preparation for other treatment modalities. The objective was to study the clinical, structural, and angiographic factors affecting complications associated with AVM treatment by sequential n-BCA embolizations for nidal occlusion versus quantitative flow reduction in preparation for surgical resection or radiosurgery. METHODS: We performed a retrospective review of all patients who underwent endovascular embolization of cerebral AVM at our institution between 1998 and 2019, during which time the technique of traditional embolization evolved to a strategy of targeted sequential flow reduction guided by serial flow imaging based on quantitative magnetic resonance angiography, in conjunction with a shift away from nidal penetration. RESULTS: Among 251 patients, 47.8% of patients presented with ruptured AVM. On average, each patient underwent 2.4 embolizations, for a total of 613 sessions. Major morbidity related to embolization occurred in 18 (7.2%) patients, but this occurred disproportionately in the traditional embolization strategy (n=16, 8%) in contrast with the flow-targeting strategy (n=2, 3.8%). Four patients (1.6%) died in the overall group, and these all occurred with the traditional embolization strategy (2% of 199 patients); no deaths occurred in the flow-targeting strategy (n=52). CONCLUSION: Embolization with n-BCA targeted to sequential flow reduction and feeder occlusion with limited nidal penetration prior to definitive surgical or radiosurgical treatment can be safely performed with low overall morbidity and mortality.

Medical management with interventional therapy versus medical management alone for unruptured brain arteriovenous malformations (ARUBA): final follow-up of a multicentre, non-blinded, randomised controlled trial.

BACKGROUND: In A Randomized trial of Unruptured Brain Arteriovenous malformations (ARUBA), randomisation was halted at a mean follow-up of 33·3 months after a prespecified interim analysis showed that medical management alone was superior to the combination of medical management and interventional therapy in preventing symptomatic stroke or death. We aimed to study whether these differences persisted through 5-years' follow-up. METHODS: ARUBA was a non-blinded, randomised trial done at 39 clinical centres in nine countries. Adults (age ≥18 years) diagnosed with an unruptured brain arteriovenous malformation, who had never undergone interventional therapy, and were considered by participating clinical centres to be suitable for intervention to eradicate the lesion, were eligible for inclusion. Patients were randomly assigned (1:1) by a web-based data collection system, stratified by clinical centre in a random permuted block design with block sizes of two, four, and six, to medical management alone or with interventional therapy (neurosurgery, embolisation, or stereotactic radiotherapy, alone or in any combination, sequence, or number). Although patients and investigators at a given centre were not masked to treatment assignment, investigators at other centres and those in the clinical coordinating centre were not informed of assignment or outcomes at any of the centres. The primary outcome was time to death or symptomatic stroke confirmed by imaging, assessed by a neurologist at each centre not involved in the management of participants' care, and monitored by an independent committee using an adaptive approach with interim analyses. Enrolment began on April 4, 2007, and was halted on April 15, 2013, after which follow-up continued until July 15, 2015. All analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, NCT00389181. FINDINGS: Of 1740 patients screened, 226 were randomly assigned to medical management alone (n=110) or medical management plus interventional therapy (n=116). During a mean follow-up of 50·4 months (SD 22·9), the incidence of death or symptomatic stroke was lower with medical management alone (15 of 110, 3·39 per 100 patient-years) than with medical management with interventional therapy (41 of 116, 12·32 per 100 patient-years; hazard ratio 0·31, 95% CI 0·17 to 0·56). Two patients in the medical management group and four in the interventional therapy group (two attributed to intervention) died during follow-up. Adverse events were observed less often in patients allocated to medical management compared with interventional therapy (283 vs 369; 58·97 vs 78·73 per 100 patient-years; risk difference -19·76, 95% CI -30·33 to -9·19). INTERPRETATION: After extended follow-up, ARUBA showed that medical management alone remained superior to interventional therapy for the prevention of death or symptomatic stroke in patients with an unruptured brain arteriovenous malformation. The data concerning the disparity in outcomes should affect standard specialist practice and the information presented to patients. The even longer-term risks and differences between the two therapeutic approaches remains uncertain. FUNDING: National Institute of Neurological Disorders and Stroke for the randomisation phase and Vital Projects Fund for the follow-up phase.

Outcomes of Surgical and Endovascular Treatment for Arterial Lesions in Intravenous Drug Abusers.

BACKGROUND: The objective of this study is to report an 18-year single-center experience in the surgical and endovascular treatment of arterial complications due to self-injection in drug abuser patients. METHODS: This retrospective single-center study was conducted analyzing a prospectively collected database including all endovascular or surgical procedures performed from January 2007 to December 2019 for any arterial complication due to self-injection in drug abuser patient. Collected data were patient demographic and comorbidity, site and type of arterial lesion (pseudoaneurysm [PA], arteriovenous fistula [AVF]), signs of systemic or local infection, and procedural data (endovascular/surgical treatment). End points were rate of postoperative complications, reintervention rate, limb salvage, and patients' early and long-term survival. RESULTS: In 11 patients (median age 36 years, range 27-47; male 73%), 13 arterial lesions were treated: 10 (77%) PA, 2 (15%) PA associated with AVF, and 1 (8%) isolated AVF. Arterial lesion involved common femoral artery in 5 (38%), superficial femoral artery in 4 (31%), profunda femoral artery in 1 (8%), brachial artery in 2 (15%), and subclavian artery in 1 (8%). Signs of infections were present in 9 of the 13 cases (69%). The treatment was surgical in 11 (85%) cases: 7 interposition graft (6 great saphenous vein, 1 arterial cryopreserved homograft), 2 direct reconstruction, 1 patch plasty with pericardium bovine patch, and 1 arterial ligation. Endovascular treatment was performed in 2 cases: 1 noninfected PA of the superficial femoral artery, and 1 55-mm PA of the postvertebral segment of the right subclavian artery with clinical sign of hemodynamic instability. At 1 month, postoperative complication rate was 8% (one lower limb claudication after superficial femoral artery ligation). Reintervention rate was 8% (interposition graft rupture for repeated self-injections). Limb salvage and patient survival were both 100%. Median follow-up was 5 years (range 1 month to 11.3 years); surgical group: median 8.2 years (range 2 months to 11.3 years); endovascular group: median 3.5 months (range 1-6). During follow-up, neither complications nor reinterventions occurred, and limb salvage was 100% for both groups. At 2, 4, and 6 years, overall estimated patient survival was 91%, 81%, and 81%, respectively, with no procedure-related death. CONCLUSIONS: After surgical or endovascular management of arterial lesions due to self-injection in drug abuser patients, complications occur mainly in the postoperative period. During follow-up, the surgical procedures have low rate of complications, reinterventions, and procedure-related mortality, whereas for the endovascular treatment the mid-term outcomes remain unknown.

Comparison of vascular access patency and patient survival between native arteriovenous fistula and synthetic arteriovenous graft according to age group.

INTRODUCTION: Arteriovenous fistula (AVF) is historically known to be the ideal option for vascular access (VA) for hemodialysis compared with arteriovenous graft (AVG). However, this approach has been recently questioned in the aging population because of their poor vessel quality and multiple comorbidities. METHODS: Data from a total of 2200 patients from the VA category of The Catholic Medical Center nephrology registry from March 2009 to February 2017 were analyzed. We compared VA patency and patient survival between two groups, AVF and AVG, according to age. FINDINGS: Compared with the AVG group, survival benefit in the AVF group continued even in patients ≥80 years. In the whole population, all the primary patency (PP), primary-assisted patency (PAP), and secondary patency (SP) measures were superior in the AVF group. With regard to subgroups, PP was comparable between the two groups in patients ≥65 years, whereas PAP and SP were superior in the AVF group even in septuagenarian patients who are from 70 to 79 years old. In patients ≥80 years, all the patency measures were comparable between the two groups. When the separate comparison of lower-arm AVF (or upper-arm AVF) and AVG, lower-arm AVF failed to demonstrate its superiority in any kind of patency in septuagenarian patients compared with AVG, whereas upper-arm AVF demonstrated its superiority in PAP and SP in septuagenarian patients. However, even upper-arm AVF failed to demonstrate its superiority in any kind of patency in patients ≥80 years. DISCUSSION: Arteriovenous fistula if using upper-arm vessel showed the superior VA patency up to septuagenarian patients, whereas, in HD patients ≥80 years, AVF and AVG were comparable in VA patency.

The Impact of Comorbidity Burden on The Association between Vascular Access Type and Clinical Outcomes among Elderly Patients Undergoing Hemodialysis.

The optimal vascular access type for elderly hemodialysis patients is controversial. We evaluated the impact of comorbidity burden on the association between vascular access type and mortality risk among 23,100 hemodialysis patients aged ≥65 years from the Korean Society of Nephrology End-Stage Renal Disease registry data. Subjects were stratified into tertiles according to the simplified Charlson comorbidity index (sCCI), and the survival and hospitalization rates were compared with respect to vascular access type: arteriovenous fistula (AVF), arteriovenous graft (AVG), and central venous catheter (CVC). Among all tertiles of sCCI, CVC use showed highest risk of mortality than AVF use. In the lowest to middle tertile, no difference was observed in survival rates between the use of AVF and AVG. However, in the highest tertile, AVG use showed higher risk of mortality than AVF use. When subjects were classified according to a combination of sCCI tertile and access type (AVF vs. AVG), patients with the highest CCI with AVG showed 1.75-folded increased risk of mortality than those with the lowest sCCI with AVF. Hospitalization rates due to access malfunction were highest in patients with CVC in all sCCI tertiles. In the highest tertile, patients with AVG showed increased rates of hospitalization compared to those with AVF due to access malfunction. However, hospitalization rates due to access infection were highest in patients with AVG in all tertiles. The use of AVF may be of benefit and switching to AVF should be considered in elderly hemodialysis patients with a high burden of comorbidity.

Risk of Complications and Survival of Patients Dialyzed with Permanent Catheters.

Background and Objectives: An increase in the incidence of end-stage renal disease (ESRD) is associated with the need for a wider use of vascular access. Although arteriovenous (A-V) fistula is a preferred form of vascular access, for various reasons, permanent catheters are implanted in many patients. Materials and Methods: A retrospective analysis of clinical data was carried out in 398 patients (204 women) who in 2010-2016 were subjected to permanent dialysis catheters implantation as first vascular access or following A-V fistula dysfunction. The factors influencing the risk of complications related to vascular access and mortality were evaluated and the comparison of the group of patients with permanent catheter implantation after A-V fistula dysfunction with patients with first-time catheter implantation was carried out. Results: The population of 398 people with ESRD with mean age of 68.73 ± 13.26 years had a total of 495 permanent catheters implanted. In 129 (32.6%) patients, catheters were implanted after dysfunction of a previously formed dialysis fistula. An upward trend was recorded in the number of permanent catheters implanted in relation to A-V fistulas. Ninety-two infectious complications (23.1%) occurred in the study population in 65 patients (16.3%). Multivariate analysis showed that permanent catheters were more often used as the first vascular access option in elderly patients and cancer patients. Mortality in the mean 1.38 ± 1.17 years (min 0.0, max 6.70 years) follow-up period amounted to 50%. Older age and atherosclerosis were the main risk factors for mortality. Patients with dialysis fistula formed before the catheter implantation had a longer lifetime compared to the group in which the catheter was the first access. Conclusion: The use of permanent catheters for dialysis therapy is associated with a relatively high incidence of complications and low long-term survival. The main factors determining long-term survival were age and atherosclerosis. Better prognosis was demonstrated in patients after the use of A-V fistula as the first vascular access option.

S100B Serum Elevation Predicts In-Hospital Mortality After Brain Arteriovenous Malformation Rupture.

Background and Purpose- S100B protein serum elevation has been associated with poor prognosis in neurologically ill patients. The purpose of this study is to determine whether elevation of S100B is associated with increased in-hospital mortality after brain arteriovenous malformation rupture. Methods- This is a retrospective study of patients admitted for brain arteriovenous malformation rupture. The study population was divided into derivation and validation cohorts. Univariate followed by multivariate logistic regression was used to determine whether elevation of S100B serum levels above 0.5 µg/L during the first 48 hours after admission (S100Bmax48) was associated with in-hospital mortality. Results- Two hundred and three ruptures met inclusion criteria. Twenty-three led to in-hospital mortality (11%). Mean S100Bmax48 was 0.49±0.62 µg/L. In the derivation cohort (n=101 ruptures), multivariate analysis found Glasgow coma scale score ≤8 (odds ratio, 21; 95% CI, 2-216; 0.001) and an S100Bmax48>0.5 µg/L (odds ratio, 19; 95% CI, 2-188; P=0.001) to be associated with in-hospital mortality. When applied to the validation cohort (n=102 ruptures), the same model found only S100Bmax48>0.5 µg/L (odds ratio, 8; 95% CI, 1.5-44; P=0.01) to be associated with in-hospital mortality. Conclusions- Elevated S100B protein serum level is strongly associated with in-hospital mortality after brain arteriovenous malformation rupture.

Vertebral Arteriovenous Fistula: A Review Article.

OBJECTIVE: Vertebrovertebral fistulas (VVFs) are uncommon lesions that can arise spontaneously or secondarily to iatrogenic or mechanical trauma. We performed a systematic review of the literature to obtain information regarding demographics, clinical presentation, treatment modalities, outcome, and complications associated with treatment. METHODS: A literature search was performed by a reference librarian and after screening, 128 case reports and 16 case series were left for inclusion in the review. All possible data were abstracted by 3 authors, results were tabulated, and descriptive statistics (mean, range, and proportions) were reported. No formal statistical analysis was performed as part of this study. RESULTS: A total of 280 patients were analyzed. VVFs can be categorized in 3 subgroups (iatrogenic, spontaneous, and traumatic), based on the mechanism of formation, and these different causes share different underlying demographics that bear important treatment considerations. Traumatic VVFs are more commonly seen in young men; the spontaneous form is more commonly seen in young women. Iatrogenic VVFs are more commonly seen in elderly people. Spontaneous VVFs are most commonly located between C1 and C2. Most iatrogenic (n = 39; 57%), spontaneous (n = 106; 82%), and traumatic (n = 53; 73%) VVFs were treated with deconstructive (defined as occlusion of fistula and feeding vessels) endovascular therapy. Overall treatment-related permanent morbidity was 3.3% (9/270) and mortality was 1.5% (4/270). CONCLUSIONS: VVFs are uncommon lesions, and treatment is often indicated, even in patients without retrograde venous drainage. When treatment is undertaken, the cause of presentation and associated patient demographics should be considered when planning the treatment strategy.

Comparison of tunneled central venous catheters and native arteriovenous fistulae by evaluating the mortality and morbidity of patients with prevalent hemodialysis.

PURPOSE: We examined the association between catheter use for maintenance hemodialysis (HD) and mortality/hospitalization in a cohort of patients with prevalent HD. METHODS: In this study, 70 HD patients with tunneled cuffed central venous catheters (TCVCs) from a Taiwanese HD center during 2014-2016 were enrolled and compared with 70 matched HD patients with native arteriovenous fistulae (AVF). The compared variables included demographic parameters and laboratory and dialysis-related indices. Cox regression analysis was used to assess the risk of mortality/hospitalization within a year. RESULTS: Low baseline serum albumin levels were found in patients with TCVCs (3.64 g/dL vs 3.79 g/dL, p = 0.030). The mortality rates of patients with AVF and TCVCs were 14 per 1000 patients and 171 per 1000 patients, respectively. Infection was the leading cause of mortality/hospitalization in patients with TCVCs. Using multivariate analyses, the risk of death was found to be significantly higher in patients with TCVCs than in those with AVF (Hazard ratio [HR] 12.15, 95% CI 1.16-127.17; p = 0.037). Patients with TCVC also had a higher hospitalization rate (HR 1.33, 95% CI 0.71-2.49; p = 0.369) (not statistically significant). CONCLUSION: Catheter use for maintenance HD was associated with increased all-cause mortality.

The Unique Features and Outcomes of Microsurgically Resected Cerebellar Arteriovenous Malformations.

BACKGROUND: Cerebellar arteriovenous malformations (CAVMs) are challenging to treat given their close proximity to the brain stem, greater propensity for rupture, and greater rates of morbidity and mortality than other brain arteriovenous malformations. The present investigation sought to describe and characterize the features of these rare and unique lesions. METHODS: A retrospective review of CAVM cases treated at 2 tertiary medical centers was performed. Patients surgically treated at institution 1 from September 1999 to February 2013 and institution 2 from October 2008 to October 2015 were included. RESULTS: A total of 120 patients had been treated. Of the 120 patients, 85 (70.8%) had initially presented with hemorrhage, 45 (37.5%) of whom experienced hemorrhage requiring emergent surgery. A favorable neurological outcome was observed in 76 patients (63.3%; modified Rankin Scale score <3). The perioperative mortality was 2.5% (n = 3). The long-term mortality rate was 7.5% (n = 9). The mean follow-up time was 1.82 years. On average, the patients with large CAVMs (≥3 cm; P ≤ 0.001), who had received embolization before surgery (P = 0.04), did not have an associated aneurysm (P ≤ 0.001), or had a residual CAVM after surgery (P = 0.008) were significantly younger. Female patients had fewer CAVMs with deep venous drainage (54.3% vs. 72.3%; P = 0.049), experienced decreased mortality (1.4% vs. 16.7%; P = 0.003), and were less likely to have worse neurological status after treatment (P = 0.003). CONCLUSIONS: CAVMs are rare lesions that exhibit unique disease characteristics. Although most patients will experience a favorable outcome, CAVMs frequently present with hemorrhage, result in high rates of morbidity and mortality, and characteristically differ depending on patient age and gender.

Stereotactic Radiosurgery for Pediatric Versus Adult Brain Arteriovenous Malformations.

Background and Purpose- The aim of this international, multicenter, retrospective matched cohort study is to directly compare the outcomes after stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVM) in pediatric versus adult patients. Methods- We performed a retrospective review of patients with AVM who underwent SRS at 8 institutions participating in the International Gamma Knife Research Foundation from 1987 to 2014. Patients were categorized into pediatric (<18 years of age) and adult (≥18 years of age) cohorts and matched in a 1:1 ratio using propensity scores. Favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes. Results- From a total of 2191 patients who were eligible for inclusion in the overall study cohort, 315 were selected for each of the matched cohorts. There were no significant differences between matched pediatric versus adult cohorts with respect to the rates of favorable outcome (59% versus 58%; P=0.936), AVM obliteration (62% versus 63%; P=0.934), post-SRS hemorrhage (9% versus 7%; P=0.298), radiological radiation-induced changes (26% versus 26%; P=0.837), symptomatic radiation-induced changes (7% versus 9%; P=0.383), or permanent radiation-induced changes (2% versus 3%; P=0.589). The all-cause mortality rate was significantly lower in the matched pediatric cohort (3% versus 10%; P=0.003). Conclusions- The outcomes after SRS for comparable AVMs in pediatric versus adult patients were not found to be appreciably different. SRS remains a reasonable treatment option for appropriately selected pediatric patients with AVM, who harbor a high cumulative lifetime hemorrhage risk. Age seems to be a poor predictor of AVM outcomes after SRS.

The Role of Doppler Ultrassonography in Significant and Borderline Stenosis Definition.

BACKGROUND: The definition of significant stenosis (SS) remains controversial. METHODS: We retrospectively reviewed 1,040 consultations. SS was defined in the presence of clinical and echo-Doppler (DDU) criteria: Qa <500 mL/min or Qa decrease >25%; RI >0.7 in the feeding artery or absolute minimal luminal stenosis diameter <2.0 mm. Stenosis without any additional criteria were considered borderline stenosis (BS). RESULTS: Two hundred twenty-one arteriovenous fistulas (AVFs) were included: 58.8% had SS, 18.6% had BS, and 22.6% had no dysfunctional access (ND). SS had a significantly higher thrombotic events than BS and ND (13.1 vs. 4.4%, p = 0.018). The annual thrombosis rate was 0.007, 0.037, and 0.004 in the ND, SS, and BS, respectively. AVF cumulative survival at 5 years was significantly lower in SS (89.5%) compared to BS (100%) and ND (97.4%; p = 0.03). BS had an HR for AVF failure of 1.1, p = 0.955, while the SS presented an HR of 5.9, p = 0.09. CONCLUSION: AVF clinical monitoring with additional DDU criteria appear to be appropriate for therapeutic referral.

Primary and secondary arterial fistulas during chronic Q fever.

OBJECTIVE: After primary infection with Coxiella burnetii, patients may develop acute Q fever, which is a relatively mild disease. A small proportion of patients (1%-5%) develop chronic Q fever, which is accompanied by high mortality and can be manifested as infected arterial or aortic aneurysms or infected vascular prostheses. The disease can be complicated by arterial fistulas, which are often fatal if they are left untreated. We aimed to assess the cumulative incidence of arterial fistulas and mortality in patients with proven chronic Q fever. METHODS: In a retrospective, observational study, the cumulative incidence of arterial fistulas (aortoenteric, aortobronchial, aortovenous, or arteriocutaneous) in patients with proven chronic Q fever (according to the Dutch Chronic Q Fever Consensus Group criteria) was assessed. Proven chronic Q fever with a vascular focus of infection was defined as a confirmed mycotic aneurysm or infected prosthesis on imaging studies or positive result of serum polymerase chain reaction for C. burnetii in the presence of an arterial aneurysm or vascular prosthesis. RESULTS: Of 253 patients with proven chronic Q fever, 169 patients (67%) were diagnosed with a vascular focus of infection (42 of whom had a combined vascular focus and endocarditis). In total, 26 arterial fistulas were diagnosed in 25 patients (15% of patients with a vascular focus): aortoenteric (15), aortobronchial (2), aortocaval (4), and arteriocutaneous (5) fistulas (1 patient presented with both an aortocaval and an arteriocutaneous fistula). Chronic Q fever-related mortality was 60% for patients with and 21% for patients without arterial fistula (P < .0001). Primary fistulas accounted for 42% and secondary fistulas for 58%. Of patients who underwent surgical intervention for chronic Q fever-related fistula (n = 17), nine died of chronic Q fever-related causes (53%). Of patients who did not undergo any surgical intervention (n = 8), six died of chronic Q fever-related causes (75%). CONCLUSIONS: The proportion of patients with proven chronic Q fever developing primary or secondary arterial fistulas is high; 15% of patients with a vascular focus of infection develop an arterial fistula. This observation suggests that C. burnetii, the causative agent of Q fever, plays a role in the development of fistulas in these patients. Chronic Q fever-related mortality in patients with arterial fistula is very high, in both patients who undergo surgical intervention and patients who do not.

Does Advanced Age Affect the Outcomes of Stereotactic Radiosurgery for Cerebral Arteriovenous Malformation?

BACKGROUND: Stereotactic radiosurgery (SRS) is generally considered a minimally invasive treatment modality. However, definitive evidence of the efficacy of SRS in the elderly population is still not available. METHODS: The outcomes of 561 elderly and nonelderly patients who underwent SRS for AVM at our institution between 1990 and 2013 were reviewed, analyzed, and compared. Elderly patients were defined as those age ≥60 years at the time of SRS. RESULTS: The elderly cohort comprised 55 patients; the nonelderly cohort, 506. In the elderly cohort, the median age was 65 years, and the duration of follow-up was 91 months. The actuarial obliteration rates were 47% at 3 years, 70% at 4 years, and 76% at 5 years in the elderly cohort, and 57% at 3 years, 76% at 4 years, and 83% at 5 years in the nonelderly cohort. In the elderly cohort, the hemorrhage rates during the post-SRS latent phase were 5.2%/year in patients with hemorrhagic onset and 0%/year in those with nonhemorrhagic onset, and event-free survival (EFS) was 93% at 6 years and 89% at 12 years. The obliteration rate, mortality, and EFS rate were not significantly different between the 2 cohorts, whereas the rate of perifocal edema was significantly lower (P = 0.021) in the elderly cohort. The pre-SRS and post-SRS hemorrhage rates were slightly higher in the elderly cohort, albeit without statistical significance. CONCLUSIONS: Therapeutic effects and outcomes of SRS are similar in elderly and nonelderly patients. Treatment-related neurologic deficits are rare, and longer EFS can be expected.

Retrospective study of long-term outcome after brain arteriovenous malformation rupture: the RAP score.

OBJECTIVE The authors aimed to design a score for stratifying patients with brain arteriovenous malformation (BAVM) rupture, based on the likelihood of a poor long-term neurological outcome. METHODS The records of consecutive patients with BAVM hemorrhagic events who had been admitted over a period of 11 years were retrospectively reviewed. Independent predictors of a poor long-term outcome (modified Rankin Scale score ≥ 3) beyond 1 year after admission were identified. A risk stratification scale was developed and compared with the intracranial hemorrhage (ICH) score to predict poor outcome and inpatient mortality. RESULTS One hundred thirty-five patients with 139 independent hemorrhagic events related to BAVM rupture were included in this analysis. Multivariate logistic regression followed by stepwise analysis showed that consciousness level according to the Glasgow Coma Scale (OR 6.5, 95% CI 3.1-13.7, p < 10-3), hematoma volume (OR 1.8, 95% CI 1.2-2.8, p = 0.005), and intraventricular hemorrhage (OR 7.5, 95% CI 2.66-21, p < 10-3) were independently associated with a poor outcome. A 12-point scale for ruptured BAVM prognostication was constructed combining these 3 factors. The score obtained using this new scale, the ruptured AVM prognostic (RAP) score, was a stronger predictor of a poor long-term outcome (area under the receiver operating characteristic curve [AUC] 0.87, 95% CI 0.8-0.92, p = 0.009) and inpatient mortality (AUC 0.91, 95% CI 0.85-0.95, p = 0.006) than the ICH score. For a RAP score ≥ 6, sensitivity and specificity for predicting poor outcome were 76.8% (95% CI 63.6-87) and 90.8% (95% CI 81.9-96.2), respectively. CONCLUSIONS The authors propose a new admission score, the RAP score, dedicated to stratifying the risk of poor long-term outcome after BAVM rupture. This easy-to-use scoring system may help to improve communication between health care providers and consistency in clinical research. Only external prospective cohorts and population-based studies will ensure full validation of the RAP scores' capacity to predict outcome after BAVM rupture.

Effect of first cannulation time and dialysis machine blood flows on survival of arteriovenous fistulas.

Background: To study the effect of cannulation time on arteriovenous fistula (AVF) survival. Methods. Analysis of two prospective databases of access operations and dialysis sessions from 12 January 2002 through 4 January 2015 with follow-up until 4 January 2016. First cannulation time (FCT), defined from operation to first cannulation, was categorized as <2 weeks, 2-4 weeks, 4-8 weeks, 8-16 weeks and ≥16 weeks. Early cannulation was defined as FCT within 4 weeks. AVF survival was defined as the date until the AVF was abandoned. Maximum machine blood flow rate (BFR) for the first 29 dialysis sessions on AVF was analysed. Results: Altogether, 1167 AVF with functional dialysis use were analysed: 667 (57%) radial cephalic AVF, 383 (33%) brachiocephalic AVF and 117 (10%) brachiobasilic AVF. The 631 (54%) AVF created in on-dialysis patients were analysed separately from 536 (46%) AVF created in pre-dialysis patients. AVF survival was similar between cannulation categories for both pre-dialysis patients (P = 0.19) and on-dialysis patients (P = 0.83). Early cannulation was associated with similar AVF survival in both pre-dialysis patients (P = 0.82) and on-dialysis patients (P = 0.17). Six consecutive successful cannulations from the start were associated with improved AVF survival (P = 0.0002). A below-median BFR at the start of dialysis was associated with better AVF survival (P < 0.0001). A below-median increase in BFR in the first 2 months was associated with worse AVF survival (P = 0.007). The type of AVF, diabetes, pre-dialysis state at operation and six successful cannulations from the start were independent predictors for AVF survival. Conclusions: FCT is not associated with AVF survival. Failures to achieve six successful cannulations from the start of dialysis and higher machine BFR in the first week of dialysis are associated with decreased AVF survival.

Association between arteriovenous fistulae and hematomas in a dialysis center in the state of Rio Grande do Sul, Southern Brazil

Introduction: Chronic kidney disease (CKD) is characterized by slow, progressive, and irreversible loss of kidney function. CKD has become a serious public health issue because of its increasing morbidity and mortality rates. The present study aimed to investigate factors associated with hematomas caused by arteriovenous fistula (AVF) at a Renal Replacement Therapy Unit in the state of Rio Grande do Sul, southern Brazil. Methods: In this cross-sectional study, 72 patients with CKD aged 18 years or over, presenting with AVF, and undergoing three hemodialysis sessions per week were evaluated from June 2014 to March 2015. Prevalence ratios (PRs) with 95% confidence intervals (95% CIs) were estimated for identification of risk factors associated with AVF. P-values < 0.05 were considered significant. Results: Sex, age, self-reported skin color, educational level, hypertension, diabetes, nephrotic syndrome, congestive heart failure, and hepatitis C were not associated with hematoma formation (i.e., all estimated PRs had p-values > 0.05). The single factor associated with hematomas was AVF time shorter than 60 days (PR = 2.04; 95% CI: 1.28-3.27; p < 0.01). Conclusion: AVF maturation time was associated with higher prevalence of hematomas at the cannulation site. Therefore, AVF time should be given special attention in patients undergoing renal therapy at dialysis centers. (AU)

Cannulation Technique and Arteriovenous Fistula Survival in Older Adult Patients on Hemodialysis.

Cannulation technique has the potential to impact arteriovenous fistula (AVF) function. The aim of this research was to determine the impact of cannulation technique on the length of the functioning AVFs in older adult patients on hemodialysis. The study included 110 participants with fistula thrombosis who had used area technique or rope ladder technique. Biochemical parameters, gender, demographic, and clinical variables were determined. Patients who used the area cannulation technique differed significantly from patients using the rope ladder technique with regard to duration of hemodialysis (p < 0.001), outcome of the AVF revision (p = 0.045), and positioning of the anastomosis (p = 0.013). The group that used the area cannulation technique had a longer duration of hemodialysis, proximal anastomoses, and more successful revisions of AVFs.