A fuzzy pattern recognition method to classify esophageal motility records.

Analysis and classification of esophageal motility records were investigated using signal processing and fuzzy-set pattern recognition techniques. A set of parameters has been extracted from the raw records and has previously been used as characterizing features. Improvements to these procedures were obtained by extracting these features from processed data, and some additional parameters were developed. The new set of features was used in the design of a fuzzy classifier, and classification accuracy was estimated using the leave-one-out technique. To our knowledge, this is the first report of the application of automatic classification to esophageal motility records.

A pattern-analysis methodology for esophageal motility records.

The features of the esophageal contractile activity recorded during swallowing have been investigated using a signal-processing approach. Data of a 10 min recording taken from 10 normal subjects have been examined. The final features of each peristaltic wave are a set of parameters comprising the locations and magnitudes of the local wavelets contributing to the peristaltic. The approach is based on an inverse filtering technique. The inverse filter, designed with a knowledge of an average peristaltic profile formed by coherent averaging of many peristaltic examples aligned to their maxima, is used to refine the process of locating the local wavelets. It is shown that the inferred wavelet structure offers a good basis for modelling the different peristaltics, and that it suggests new parameters for esophageal characterization and classification procedures.

Tauberian-prony feature extraction technique for esophageal motility patterns.

For the esophageal contractile activity recorded during swallowing, a feature extraction scheme has been developed. It recognizes the time, duration, and amplitudes of local peaks for each peristaltic wave. The method is based on the Tauberian approximation for modeling waveforms as a sum of identically shaped pulses with different time delays and amplitudes. Initial conditions on the pulse properties are set and an optimal solution is sought. The method is completely automated and can be utilized for characterization and classification purposes.

Should both schistosomal and nonschistosomal variceal bleeders be disconnected?

Splenopancreatic disconnection (SPD) was conceived and implemented as a technical addition to distal splenorenal shunt (DSRS) to maintain its selectivity and preserve portal perfusion. The proposed hemodynamic and metabolic stability of hepatocytes after DSRS-SPD should improve survival. In this nonrandomized study, 145 consecutive (Child A/B) variceal bleeders were electively subjected to selective shunt with DSRS in 93 and DSRS-SPD in 52 patients. The 2 groups were similar before surgery with a mean follow up of 24 +/- 12 (DSRS) and 27 +/- 14 (DSRS-SPD) months. DSRS-SPD had an operative mortality of 3.8%. Postoperative pancreatitis occurred in 7.7% after DSRS-SPD and 3.2% after DSRS alone, with schistosomal hepatic fibrosis representing 86% of morbid cases. Shunt patency was high and recurrent variceal hemorrhage was low in both groups. Clinical encephalopathy was significantly reduced after DSRS-SPD (p less than 0.05). The addition of SPD significantly reduced both the incidence of chronic hyperbilirubinemia in the schistosomal patients (p less than 0.05) and the difference between the changes in total serum bilirubin in all patients (p = 0.001). Portal perfusion was preserved after DSRS-SPD in all of the angiographically-studied patients. The overall survival was 84% after DSRS and 88% after DSRS-SPD. The schistosomal patients showed an incidence of 95% and 96% survival after DSRS and DSRS-SPD, respectively. DSRS-SPD was able to improve survival (92%) better than DSRS (77%) among well-matched nonschistosomal patients. These data show: (1) DSRS-SPD still has low operative mortality and a high patency rate with a low incidence of recurrent variceal hemorrhage, (2) DSRS-SPD maintains portal perfusion, achieves better survival, and reduces the incidence of encephalopathy, especially in patients with nonalcoholic cirrhosis and mixed liver disease, (3) in the schistosomal population, DSRS-SPD reduces the incidence of chronic hyperbilirubinemia but increases the risk of postoperative pancreatitis.

Selective shunt versus nonshunt surgery for management of both schistosomal and nonschistosomal variceal bleeders.

This clinical study included 219 (Child A/B) consecutive variceal bleeders. Electively 123 had distal splenorenal shunt (DSRS) and 96 had splenectomy with gastroesophageal devascularization (S&GD). Liver pathology was documented in 73% of patients, with schistosomal fibrosis in 41% and nonalcoholic cirrhosis or mixed pattern (fibrosis and cirrhosis) in 59%. The surgical groups were similar before operation, with a mean follow-up of 82 +/- 13 and 78 +/- 18 months, respectively (range, 60 to 120 months). The two pathologic populations were also similar before each and both procedures. The operative mortality rates were low, with incidences of 3.3% (DSRS) and 3.1% (S&GD). Rebleeding occurred significantly (p less than 0.05) more frequently after S&GD (27%) compared to DSRS (5.7%). Sclerotherapy salvaged 65% of S&GD rebleeders. Encephalopathy developed significantly (p less than 0.05) more after DSRS (18.7%) compared to S&GD (7.3%), with no significant difference among the current survivors. The difference in overall rebleeding and encephalopathy rates between both procedures was statistically related to patients with cirrhosis and mixed lesions (p less than 0.05). Distal splenorenal shunt significantly reduced the endoscopic variceal size more than S&GD (p less than 0.05). Prograde portal perfusion was documented in 94% of patients in each group, with a variable distinct pattern of portaprival collaterals in 91% (DSRS) and 65% (S&GD). The total population cumulative survival was similar with 80% for DSRS and 79% for S&GD (plus sclerosis in 23%), with hepatic cell failure the cause of death in 46% and 50%, respectively. However, in the schistosomal patients, survival was better improved after DSRS (90%) compared to S&GD (75%), with no difference among the cirrhotic and mixed group (DSRS 73%, S&GD 72%). In conclusion (1) both DSRS and S&GD have low operative mortality rates, (2) DSRS is superior to S&GD in the schistosomal patients, and (3) S&GD backed by endosclerosis for rebleeding is a good surgical alternative to selective shunt in the nonalcoholic cirrhotic and mixed population.

Selective shunt in schistosomiasis in Egypt.

A joint study of the selective shunt in schistosomiasis was conducted in Egypt by the Mansoura University and Emory liver research teams. One hundred seventy patients with biopsy-proven hepatic schistosomiasis and a history of variceal bleeding were included in the study. The findings indicate that this procedure is safe and effective in the treatment of this patient population.

Schistosomal versus nonschistosomal variceal bleeders. Do they respond differently to selective shunt (DSRS)?

The distal splenorenal shunt (DSRS) was performed in 125 consecutive variceal bleeders. To date, no patients have been lost to follow-up (mean of 79 +/- 20 months). Liver pathology was documented in 85 patients: 45 patients had schistosomal hepatic fibrosis, 17 had nonalcoholic cirrhosis, and 23 had mixed pattern (hepatic fibrosis and cirrhosis). The preoperative data base for these three groups was matched (p greater than 0.05), with a mean follow-up of 79 +/- 20, 70 +/- 14, and 77 +/- 22 months for each population, respectively. The results showed low operative mortality (4.8%), high cumulative patency rate (94.8%) and low recurrent variceal hemorrhage (5.6%). The biochemical data showed significant increase in serum bilirubin (p less than 0.001) and aspartate transaminase (AST) (p less than 0.05) in the nonschistosomal patients. Chronic hyperbilirubinemia was found in 33% of the schistosomal group. Prograde portal perfusion was detected in 94% of the patients, with development of collaterals in 91%. The angiographic pattern of these collaterals was 50% pancreatic, 45% gastric, and 26% colosplenic. Patients with mixed liver disease had a high incidence of Grade III portal perfusion (57%) and more common pancreatic and gastric collaterals (71%). The cumulative survival for all patients was 74.1%, with hepatic cell failure being the leading cause of death (13 patients, 50% of all deaths). The schistosomal patients had a 91.6% incidence, whereas the cirrhotic and mixed groups had survival rates of 75.6% and 65.2%, respectively. Also, of a 15% total incidence of encephalopathy, 4.4% was related to the schistosomal patients, 23.5% to the cirrhotics, and 21.7% to the mixed population. Statistically, the survival rate was significantly better (p less than 0.05) and encephalopathy was significantly lower (p less than 0.05) in the schistosomal population. In conclusion, this data shows that: 1) DSRS has a high patency rate and a low variceal hemorrhage recurrence rate; 2) it maintains some degree of portal perfusion in patients with different nonalcoholic liver diseases, despite development of collaterals; and 3) the schistosomal patients have a better survival rate, with a low incidence of encephalopathy after DSRS, compared with the cirrhotic and mixed populations.

Distal splenorenal shunt for management of variceal bleeding in patients with schistosomal hepatic fibrosis.

The distal splenorenal shunt was performed in 60 patients with schistosomal hepatic fibrosis in whom no evidence of cirrhosis was documented by preoperative needle and operative wedge biopsy. No patients have been lost to follow-up with a median of 37 months (range: 17-86). The results showed low operative mortality (1.7%), high patency rate (92.5%), and low recurrent variceal hemorrhage (6.7%). Thrombosed shunts were treated either by refashioning the shunt (1 patient) or splenectomy and gastric devascularization (2 patients). Initial hyperbilirubinemia and reduction in serum albumin were found in the early postoperative period, with persistent hyperbilirubinemia in 32% of the patients. The 5-year survival was 88%, with liver disease related mortality in only three patients. Clinical encephalopathy was detected in three patients (5.1%); only one of them was incapacitated. These data showed that: selective shunt (distal splenorenal shunt, DSRS) is an effective surgical procedure in the treatment of schistosomal variceal bleeding, shunt thrombosis is rare and can possible be corrected if detected early, schistosomal patients have a better survival and a lower incidence of encephalopathy after DSRS than that reported in cirrhotics, and liver biopsy should be performed for proper assessment of the schistosomal population especially in the geographic areas where the schistosoma parasite and viral hepatitis are endemic.