Accuracy of 3.0T magnetic resonance angiography for the detection of arteriovenous fistula dysfunction in hemodialysis patients requiring interventional therapy: a prospective study

Background

Color Doppler ultrasonography (CDUS) is feasible to detect arteriovenous fistula (AVF) dysfunction in hemodialysis patients but is not sufficient to map the structure of fistula required for interventions. This study is designed to evaluate the diagnostic accuracy of three-dimensional time-of-flight magnetic resonance angiography (TOF-MRA) at 3.0T versus CDUS for AVF dysfunction, by using digital subtraction angiography (DSA) as reference.

Methods

This prospective study enrolled 68 consecutive patients with dysfunctional AVF who underwent both CDUS and TOF-MRA at Shanghai Sixth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine. The analysis of the dysfunctional AVFs was divided into three regions: the feeding artery, fistula and draining veins. In the whole- and per-regional-based analyses, two observers who were blinded to the clinical and DSA results independently analyzed all CDUS and TOF-MRA datasets. The image quality and stenosis severity of the lesions on TOF-MRA were evaluated. A receiver operating characteristic curve was applied to analyze the detection of AVF dysfunction with TOF-MRA.

Results

A total of 204 vessel regions were evaluated. The whole-region-based image quality of TOF-MRA was poorer in patients with a total occlusion (1.8±0.8) than in those with stenosis (2.7±0.6, P<0.001). In the whole-region analyses, TOF-MRA had higher sensitivity [99.1% (94.6-100.0%) vs. 82.9% (74.6-89.0%), P<0.001] and similar specificity [93.1% (85.0-97.1%) vs. 94.3% (86.5-97.9%), P=0.755] than CDUS. The per-region-based analyses showed that TOF-MRA yielded higher sensitivity [fistula region, 98.1% (88.4-99.9%) vs. 80.8% (67.0-89.9%); P=0.004; draining vein region, 100.0% (92.5-100.0%) vs. 85.0% (72.9-2.5%); P=0.003] and similar specificity [fistula region, 88.2% (62.3-97.8%) vs. 88.2% (62.3-97.9%); P>0.99; draining vein region, 100.0% (59.8-100.0%) vs. 87.5% (46.7-99.3%); P>0.99] than CDUS. Sensitivity and specificity of TOF-MRA were comparable to those of CDUS in feeding artery region.

Conclusions

TOF-MRA is a feasible and accurate method to display AVF dysfunction in hemodialysis patients, and this method might fulfill the endovascular treatment planning requirements.

[Efficacy of intravenous drug information management system on the improvement of anemia in maintenance hemodialysis patients]

Objective: To investigate the effect of information management of intravenous drugs on anemia in maintenance hemodialysis patients. Methods: The information management of intravenous drugs was a management system developed by the Hemodialysis Center of Shanghai Jiao Tong University School of Medicine Affiliated Sixth People's Hospital in April 2020. The parameters six months before and after the use of the information management system were retrospectively collected and compared, including the rate of reaching the standard of hemoglobin, ferritin, transferrin saturation rate and the incidence of cardiovascular events. Specifically, the control stage was from October 2019 to March 2020, which was before the use of information management, and the study stage was from April to September 2020, which was after the use of information management. Results: There were 285 patients (190 males and 95 females) included in the control stage, with an average age of (62.4±13.2) years, while 278 patients (193 males and 85 females) were included in the study stage, with an average age of (62.8±13.2) years. Compared with the control stage, the rate of reaching the standard of hemoglobin [47.8% (797/1 668) vs 40.2% (687/1 710), P<0.001], ferritin [39.0% (217/556) vs 31.2% (178/570), P=0.006], and transferrin saturation [64.7% (360/556) vs 58.6% (334/570), P=0.034] increased in the study stage. The incidence of cardiovascular events in the study stage was 11.2% (31/278), which was significantly lower than that in the control stage [16.5% (47/285)] (P=0.043). Conclusion: The information management of intravenous drugs in the hemodialysis center may help improve the anemia status in maintenance hemodialysis patients.

[Related factors of internal border-zone infarcts in patients with symptomatic chronic internal carotid artery occlusion]

Objective: To explore the related factors of internal border-zone (IBZ) infarcts in patients with symptomatic chronic internal carotid artery occlusion (CICAO). Methods: From January 2011 to May 2019, the symptomatic CICAO patients in the Second Affiliated Hospital of Soochow University and the Ninth People's Hospital of Suzhou were retrospectively analyzed. The patients were divided into IBZ group and non-IBZ group. The demographic data, laboratory examination and imaging data of the two groups were collected. Binary logistic regression analysis was used to identify the related factors of IBZ infarcts in patients with symptomatic CICAO. Results: A total of 185 patients (147 males and 38 females) were finally enrolled, with a mean age of (65±11) years old. There were 64 and 121 cases in IBZ group and non-IBZ group, respectively. The ratio of patients with ophthalmic artery (OA) reflux in IBZ group was 64.1% (41/64), which was significantly higher than that in non IBZ group [47.8% (55/121), P=0.037], while the ratio of patients with collateral compensation (ASTIN/SIR 3-4) in non-IBZ group was 66.1% (80/121), which was significantly higher than that in IBZ group [29.7% (19/64), P<0.001]. Multivariate logistic regression analysis showed that history of cerebral infarction (OR=2.233, 95%CI: 1.023-4.874), low density lipoprotein (LDL) (OR=1.516, 95%CI: 1.006-2.285) and OA reflux (OR=5.060, 95%CI: 1.160-22.081) were independent risk factors for IBZ infarcts in patients with symptomatic CICAO (all P<0.05); while prothrombin international normalized ratio (INR) (OR=0.010, 95%CI: 0.000-0.970) and collateral compensation (ASTIN/SIR 3-4) (OR=0.172, 95%CI: 0.079-0.373) were protective factors (all P<0.05). Conclusion: OA reflux, LDL, and history of cerebral infarction are independent risk factors for IBZ infarcts in patients with symptomatic CICAO, while INR and collateral compensation scores (ASTIN/SIR 3-4) are the protective factors.

Optimal Design for Marker-assisted Gene Pyramiding in Cross Population

Marker-assisted gene pyramiding aims to produce individuals with superior economic traits according to the optimal breeding scheme which involves selecting a series of favorite target alleles after cross of base populations and pyramiding them into a single genotype. Inspired by the science of evolutionary computation, we used the metaphor of hill-climbing to model the dynamic behavior of gene pyramiding. In consideration of the traditional cross program of animals along with the features of animal segregating populations, four types of cross programs and two types of selection strategies for gene pyramiding are performed from a practical perspective. Two population cross for pyramiding two genes (denoted II), three population cascading cross for pyramiding three genes(denoted III), four population symmetry (denoted IIII-S) and cascading cross for pyramiding four genes (denoted IIII-C), and various schemes (denoted cross program-A–E) are designed for each cross program given different levels of initial favorite allele frequencies, base population sizes and trait heritabilities. The process of gene pyramiding breeding for various schemes are simulated and compared based on the population hamming distance, average superior genotype frequencies and average phenotypic values. By simulation, the results show that the larger base population size and the higher the initial favorite allele frequency the higher the efficiency of gene pyramiding. Parents cross order is shown to be the most important factor in a cascading cross, but has no significant influence on the symmetric cross. The results also show that genotypic selection strategy is superior to phenotypic selection in accelerating gene pyramiding. Moreover, the method and corresponding software was used to compare different cross schemes and selection strategies.