• Archives of Reconstructive Microsurgery
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• v.23 no.2
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• pp.97-100
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• 2014

The number of patients with chronic renal failure who require renal replacement therapy is increasing and dialysis is still the mainly used renal replacement therapy. The first choice of surgical technique currently used is side-to-end anastomosis of the radial artery and the cephalic vein. The authors report on a case of an effective arteriovenous shunt operation performed using microscopy. A 53-year-old male with chronic renal failure was referred to plastic and reconstructive surgery department to undergo an arteriovenous shunt operation. Venography was performed before surgery in order to find the appropriate vessel for the arteriovenous shunt operation. The cephalic vein on the wrist showed a diameter of over 4 mm, which was appropriate for an arteriovenous shunt operation. Anastomosis of the vessels was performed under microscopy using Nylon #9-0. Blood flow and vessel diameter were evaluated by venography after surgery and showed well maintained function of the shunt. Complications such as bleeding, edema of the upper arm, and wound dehiscence did not occur. Many factors and certain complications may affect the long-term patency of an arteriovenous shunt; however, exquisite surgical technique is the most important factor in a successful operation. Thus, arteriovenous shunt operation using microscopy is thought to be a good treatment option.

• Journal of Chest Surgery
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• v.11 no.2
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• pp.227-231
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• 1978

Since January 1973 we have performed 47 arteriovenous shunts and 22 arteriovenous fistulas for 57 patients with acute or chronic renal failure. Of these 57 cases, 50 cases had chronic renal failure and the other 7 cases had acute renal failure. The most frequent complications after operations were thrombosis, bleeding and infection. Less frequently dislodgement of shunt and aneurysmal change of the fistula were found. After 47 arteriovenous shunts, 21 those complications [44%] were found. On the other hand after 22 arteriovenous fistulas, 5 complications were found. Now we are using the arteriovenous shunt only for the patients who need emergency short term hemodialysis and temporary dialysis until arteriovenous fistula could be used.

• Korean Journal of Radiology
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• v.23 no.10
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• pp.949-958
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• 2022

Objective: To investigate the feasibility of using a deep learning-based analysis of auscultation data to predict significant stenosis of arteriovenous fistulas (AVF) in patients undergoing hemodialysis requiring percutaneous transluminal angioplasty (PTA). Materials and Methods: Forty patients (24 male and 16 female; median age, 62.5 years) with dysfunctional native AVF were prospectively recruited. Digital sounds from the AVF shunt were recorded using a wireless electronic stethoscope before (pre-PTA) and after PTA (post-PTA), and the audio files were subsequently converted to mel spectrograms, which were used to construct various deep convolutional neural network (DCNN) models (DenseNet201, EfficientNetB5, and ResNet50). The performance of these models for diagnosing ≥ 50% AVF stenosis was assessed and compared. The ground truth for the presence of ≥ 50% AVF stenosis was obtained using digital subtraction angiography. Gradient-weighted class activation mapping (Grad-CAM) was used to produce visual explanations for DCNN model decisions. Results: Eighty audio files were obtained from the 40 recruited patients and pooled for the study. Mel spectrograms of "pre-PTA" shunt sounds showed patterns corresponding to abnormal high-pitched bruits with systolic accentuation observed in patients with stenotic AVF. The ResNet50 and EfficientNetB5 models yielded an area under the receiver operating characteristic curve of 0.99 and 0.98, respectively, at optimized epochs for predicting ≥ 50% AVF stenosis. However, Grad-CAM heatmaps revealed that only ResNet50 highlighted areas relevant to AVF stenosis in the mel spectrogram. Conclusion: Mel spectrogram-based DCNN models, particularly ResNet50, successfully predicted the presence of significant AVF stenosis requiring PTA in this feasibility study and may potentially be used in AVF surveillance.

• Journal of Chest Surgery
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• v.53 no.3
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• pp.121-126
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• 2020

Background: The aim of this study was to analyze the clinical outcomes of autogenous brachiocephalic arteriovenous fistulas and to investigate the factors associated with 1-year patency after initiation of hemodialysis. Methods: We retrospectively reviewed the medical records of 41 patients who underwent surgery to create an autogenous brachiocephalic arteriovenous fistula between January 2015 and December 2017, received hemodialysis at the same hospital for longer than 1 year, and were monitored for their vascular access status. Intraoperative flow was measured using transit-time ultrasonography. Results: The 1-year primary and secondary patency rates were 61% (n=25) and 87.8% (n=36), respectively. The functional group (subjects who required no intervention to maintain patency within the first year after hemodialysis initiation) displayed a significantly higher median intraoperative flow rate (450 mL/min) than the non-functional group (subjects who required intervention at least once regardless of 1-year patency) (275 mL/min) (p=0.038). Based on a receiver operating characteristic curve analysis, all patients were additionally subdivided into a high-flow group (>240 mL/min) and a low-flow group (≤240 mL/min). The high-flow group included a significantly greater number of functional brachiocephalic arteriovenous fistulas than the low-flow group (74.2% vs. 20%, respectively; p=0.007). Conclusion: Transit-time flow, as measured with intraoperative transit-time ultrasonography, was associated with patency without the need for intervention at 1 year after initiation of hemodialysis.