This paper proposes the evaluation of arteriovenous shunt (AVS) stenosis using a fractional-order Fuzzy Petri net based screening system for long-term hemodialysis treatment of patients. The screening system uses the ...This paper proposes the evaluation of arteriovenous shunt (AVS) stenosis using a fractional-order Fuzzy Petri net based screening system for long-term hemodialysis treatment of patients. The screening system uses the Burg method, the fractional-order chaos system, and the Fuzzy Petri net (FPN) for early detection of AVS dysfunction. The Burg method is an autoregressive (AR) model that is used to estimate the frequency spectra of a phonoangiographic signal and to identify the spectral peaks in the region from 25 Hz to 800 Hz. In AVS, the frequency spectrum varies between normal blood flow and turbulent flow. The power spectra demonstrate changes in frequency and amplitude as the degree of stenosis changes. A screening system combining fractional-order chaos system and FPN is used to track the differences in the frequency spectra between the normal and stenosis access. The dynamic errors are indexes that can be used to evaluate the degree of AVS stenosis using a FPN. For 42 long-term follow-up patients, testing results show that the proposed screening system is more efficient in the evaluation of AVS stenosis.展开更多
Objective To investigate the clinical features of intrahepatic arteriovenous shunt (AVS) in patients with hepatic carcinoma. Methods The clinical data including results of therapy of 538 hepatic carcinoma patients adm...Objective To investigate the clinical features of intrahepatic arteriovenous shunt (AVS) in patients with hepatic carcinoma. Methods The clinical data including results of therapy of 538 hepatic carcinoma patients admitted between 1996 and 2001 were retrospectively reviewed. Results There were 71 cases of AVS altogether with 61 cases of arterio-portal shunt and 8 cases of hepatic arterior-venous shunt. Thirty out of 39 AVS cases with fistula formed between hepatic artery and main portal branch developed portal hypertension. The patients received a total of 84 sessions of transarterial chemotherapy and embolization (TACE) with a success rate of 61% (51 sessions). After TACE liver failure ensued in 3 cases. The mean survival time of these patients was 5. 77 months. Conclusion Arterio-portal /venous fistula is a common complication among hepatic carcinoma patients which ofter predicts poor prognosis. A high percentage of AVS patients will not tolerate TACE and in which the portal hypertension will be展开更多
Gastrointestinal arterio-venous malformations are a known cause of gastrointestinal bleeding. We present a rare case of persistent rectal bleeding due to a rectal arterio-portal venous fistula in the setting of portal...Gastrointestinal arterio-venous malformations are a known cause of gastrointestinal bleeding. We present a rare case of persistent rectal bleeding due to a rectal arterio-portal venous fistula in the setting of portal hypertension secondary to portal vein thrombosis. The portal hypertension was initially surgically treated with splenectomy and a proximal splenorenal shunt. However, rectal bleeding persisted even after surgery, presenting us with a diagnostic dilemma. The patient was re-evaluated with a computed tomography mesenteric angiogram which revealed a rectal arterio-portal fistula. Arterio-portal fistulas are a known but rare cause of portal hypertension, and possibly the underlying cause of continued rectal bleeding in this case. This was successfully treated using angiographic localizationand super-selective embolization of the rectal arterioportal venous fistula via the right internal iliac artery. The patient subsequently went on to have a full term pregnancy. Through this case report, we hope to high-light awareness of this unusual condition, discuss the diagnostic workup and our management approach.展开更多
文摘This paper proposes the evaluation of arteriovenous shunt (AVS) stenosis using a fractional-order Fuzzy Petri net based screening system for long-term hemodialysis treatment of patients. The screening system uses the Burg method, the fractional-order chaos system, and the Fuzzy Petri net (FPN) for early detection of AVS dysfunction. The Burg method is an autoregressive (AR) model that is used to estimate the frequency spectra of a phonoangiographic signal and to identify the spectral peaks in the region from 25 Hz to 800 Hz. In AVS, the frequency spectrum varies between normal blood flow and turbulent flow. The power spectra demonstrate changes in frequency and amplitude as the degree of stenosis changes. A screening system combining fractional-order chaos system and FPN is used to track the differences in the frequency spectra between the normal and stenosis access. The dynamic errors are indexes that can be used to evaluate the degree of AVS stenosis using a FPN. For 42 long-term follow-up patients, testing results show that the proposed screening system is more efficient in the evaluation of AVS stenosis.
文摘Objective To investigate the clinical features of intrahepatic arteriovenous shunt (AVS) in patients with hepatic carcinoma. Methods The clinical data including results of therapy of 538 hepatic carcinoma patients admitted between 1996 and 2001 were retrospectively reviewed. Results There were 71 cases of AVS altogether with 61 cases of arterio-portal shunt and 8 cases of hepatic arterior-venous shunt. Thirty out of 39 AVS cases with fistula formed between hepatic artery and main portal branch developed portal hypertension. The patients received a total of 84 sessions of transarterial chemotherapy and embolization (TACE) with a success rate of 61% (51 sessions). After TACE liver failure ensued in 3 cases. The mean survival time of these patients was 5. 77 months. Conclusion Arterio-portal /venous fistula is a common complication among hepatic carcinoma patients which ofter predicts poor prognosis. A high percentage of AVS patients will not tolerate TACE and in which the portal hypertension will be
文摘Gastrointestinal arterio-venous malformations are a known cause of gastrointestinal bleeding. We present a rare case of persistent rectal bleeding due to a rectal arterio-portal venous fistula in the setting of portal hypertension secondary to portal vein thrombosis. The portal hypertension was initially surgically treated with splenectomy and a proximal splenorenal shunt. However, rectal bleeding persisted even after surgery, presenting us with a diagnostic dilemma. The patient was re-evaluated with a computed tomography mesenteric angiogram which revealed a rectal arterio-portal fistula. Arterio-portal fistulas are a known but rare cause of portal hypertension, and possibly the underlying cause of continued rectal bleeding in this case. This was successfully treated using angiographic localizationand super-selective embolization of the rectal arterioportal venous fistula via the right internal iliac artery. The patient subsequently went on to have a full term pregnancy. Through this case report, we hope to high-light awareness of this unusual condition, discuss the diagnostic workup and our management approach.
