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Biomedical subjects

L F Rikkers

Publications and source records attributed to L F Rikkers.

At least 19 recordsLinked to original sources
PubMed1992

Distal spleno-renal shunt versus endoscopic sclerotherapy in the prevention of variceal rebleeding. A meta-analysis of 4 randomized clinical trials.

Meta-analysis was used to evaluate 4 clinical trials comparing distal spleno-renal shunt (DSRS) with endoscopic sclerotherapy (EVS) in the prevention of variceal rebleeding: the interval between bleeding and therapy ranges from < 14 days to > 100 days. A questionnaire was sent to each author of the published trials concerning methods, definitions and results of the trials in order to obtain more detailed and up-to-date information. The selected end-points for the meta-analysis were: rebleeding, mortality and chronic encephalopathy. Analysis of the results in the questionnaires was made using the method proposed by Collins. The pooled relative risk (i.e. the combined Odds ratio of each trial as an estimate of overall efficacy) of rebleeding was statistically reduced by DSRS (0.16; 95% confidence interval 0.10-0.27). Despite this, the overall risk of death following DSRS was only marginally decreased (0.78; 95% confidence interval 0.47-1.29); the lack of homogeneity in the results does not permit any significant conclusions on this end-point. However, in non-alcoholic patients, the decrease in risk of death was greater, and this without heterogeneity, following DSRS than EVS (0.59; 95% confidence interval 0.23-1.50). The overall risk of chronic encephalopathy was slightly increased after DSRS (1.86; 95% confidence interval 0.90-3.86). In conclusion, DSRS significantly reduced the risk of rebleeding compared to EVS without increasing the risk of chronic hepatic encephalopathy. However, DSRS did not significantly affect the overall death risk. Only in non-alcoholic disease did it seem to show an advantage over EVS.

Brain Diseases↗
PubMed1992

Cause and management of upper gastrointestinal bleeding after distal splenorenal shunt.

BACKGROUND: The aims of this study were to determine the causes of recurrent upper gastrointestinal hemorrhage (UGH) after distal splenorenal shunting (DSRS) and to summarize our experience in the prevention and management of this complication. METHODS: This study is based on a retrospective review of 145 consecutive patients undergoing DSRS from 1978 through 1991. RESULTS: Recurrent UGH developed in 19 patients (13%), most frequently secondary to residual portal hypertension (84%). Eight patients had shunt thrombosis and 11 had patent shunts. The incidence of shunt thrombosis was significantly greater in patients whose splenic vein was less than or equal to 8 mm in diameter (44%) than those whose splenic vein was greater than 8 mm (7%, p less than 0.001). The frequency of shunt failure from 1985 through 1991 was significantly lower (2%) than from 1978 through 1984 (10%, p less than 0.05). Five patients, all with occluded shunts, underwent surgical treatment for recurrent UGH and three died (60%). Fourteen patients were managed nonoperatively, with a mortality rate of 38%. CONCLUSIONS: Recurrent UGH after DSRS occurs in patients with patent shunts and in those with occluded shunts; DSRS thrombosis is more frequent when the splenic vein diameter is less than or equal to 8 mm; DSRS thrombosis decreases with operative experience; and the mortality rate for this complication is high with both operative and nonoperative management.

Gastrointestinal Hemorrhage↗
PubMed1992

Which portosystemic shunt is best?

No single shunt operation is ideal for all patients or all circumstances. The selective distal splenorenal shunt is preferred for the majority of patients, because it has the potential to preserve hepatic portal perfusion. Most evidence suggests that the distal splenorenal shunt is followed by a lower frequency of encephalopathy than is any type of nonselective shunt. Although theoretically attractive, the small-diameter interposition portacaval shunt has not yet been subjected to the scrutiny of controlled trials.

Esophageal and Gastric Varices↗
PubMed1991

The significance of portal vein thrombosis after distal splenorenal shunt.

The aims of this study were to determine the incidence of portal vein thrombosis after the distal splenorenal shunt, to identify any predictive factors, and to assess the clinical significance of this complication. Preoperative and postoperative angiograms and clinical evaluation were reviewed in 124 patients who underwent distal splenorenal shunts. Total and partial portal vein thrombosis were seen on 13 (10.5%) and 22 (17.7%) postoperative angiograms, respectively. The only preoperative variable correlating with development of portal vein thrombosis was portal venous perfusion, which was significantly lower in patients with than in those without portal vein thrombosis. In six of 10 patients with postoperative pancreatitis, portal vein thrombosis developed. The frequency of early postoperative complications was significantly greater in patients with total portal vein thrombosis than in those with partial or no thrombosis. Long-term follow-up has shown no significant effects of portal vein thrombosis on late ascites, encephalopathy, or survival.

Ascites↗
PubMed1991

Influence of the etiology of pancreatitis on the natural history of pancreatic pseudocysts.

We reviewed our experience with 90 patients with pancreatic pseudocysts to determine if the cause of pancreatitis influenced the patients' outcome. Acute pancreatitis (AP) occurred in 57 (63%) patients due to alcoholic (n = 15), postoperative (n = 14), biliary (n = 12), and other etiologies (n = 16). Thirty-three (37%) patients had chronic pancreatitis (CP) secondary to alcohol use (n = 27) or other causes (n = 6). Multiple pseudocysts were significantly more frequent in patients with acute alcoholic pancreatitis than in patients with chronic pancreatitis (47% versus 19%, p < 0.05). Spontaneous resolution occurred within 8 weeks in 10 (11%) patients with pseudocysts (AP = 9%, CP = 15%, p = NS). However, no patient with pseudocyst associated with biliary or postoperative pancreatitis underwent spontaneous resolution. Although pseudocysts associated with chronic pancreatitis were smaller in size (8.0 +/- 4.7 versus 5.7 +/- 3.8 cm, p < 0.05), a similar proportion of them required operation compared with AP pseudocysts (56% versus 58%). There were significantly more deaths in patients with postoperative pancreatitis compared with all other groups (29% versus 7%, p < 0.05). The outcome of pseudocysts was similar regardless of size (greater than 6 cm versus less than 6 cm) and presentation (acute versus delayed). Thus, the etiology of pancreatitis was a more important determinant of pseudocyst outcome than pseudocyst size or presentation.

Acute Disease↗
PubMed1991

Small intestinal transit in the portal hypertensive rat.

The purpose of this study was to determine the effects of portal hypertension on gastrointestinal transit. Portal hypertension was induced in a group of 15 rats by the staged portal vein ligation technique. A control group of 15 rats underwent a sham operation. Ten days later, a 51Cr-labeled Krebs' buffer solution was instilled into the duodenum and the distribution or radioactivity along the length of the small intestine was determined after 15, 30, and 60 minutes. Portal hypertension was consistently established in the study group; splenic pulp pressure (mm Hg, mean +/- SD, portal hypertensive vs. control) was 20.0 +/- 3.9 vs. 12.7 +/- 3.9, P less than 0.002. Various measures of intestinal transit revealed delayed transit in the portal hypertensive group. Retention of radioactivity in the most proximal quartile of the intestine was greater [percentage retained (portal hypertensive vs. control) was 57.9 +/- 17.3 vs. 31.2 +/- 15.3, P less than 0.02, 49.1 +/- 15.5 vs. 28.3 +/- 4.8, P = 0.03, and 42.4 +/- 17.6 vs. 29.0 +/- 8.8, P = 0.08, at 15, 30, and 60 minutes, respectively] and the geometric mean of transit was located more proximally (P less than 0.02) at each study interval in the portal hypertension group. It was concluded that portal hypertension is associated with delayed intestinal transit. This abnormality could predispose to bacterial overgrowth and contribute to altered digestion and absorption.

Animals↗
PubMed1991

Selective variceal decompression: current status.

Since its introduction into clinical practice in 1967, selective variceal decompression by means of a distal splenorenal shunt (DSRS) has become one of the more commonly performed portal-systemic shunting procedures in the treatment of variceal hemorrhage throughout the world. In addition to selective decompression of gastroesophageal varices, the DSRS provides the advantages of preservation of portal perfusion of the liver and maintenance of intestinal venous hypertension. Many large, uncontrolled series and the majority of controlled randomized studies have demonstrated a lower incidence of encephalopathy after the DSRS than after nonselective shunt procedures. A secondary advantage of the DSRS is that the hepatic hilum is avoided, thus making subsequent liver transplantation a less formidable procedure. None of the studies have shown an advantage to this shunt with respect to long-term survival in patients with alcoholic cirrhosis. However, some of the large, uncontrolled series have shown that survival is significantly improved in patients with non-alcoholic cirrhosis compared to nonselective shunt procedures in the same population. Controlled trials comparing the DSRS to endoscopic sclerotherapy have shown that chronic endoscopic variceal sclerosis is an appropriate initial therapy for most patients as long as shunt surgery is readily available if sclerotherapy fails.

Contraindications↗
PubMed1990

Gastric emptying of liquids and solids in the portal hypertensive rat.

The effects of portal hypertension on gastric motor function were investigated using the rat staged portal vein ligation model. Gastric emptying of liquids and solids was studied separately following meals labeled with 51Cr or 99Tc by whole stomach scintillation counting. Portal hypertension was consistently established in experimental rats (splenic pulp pressure: mean +/- SEM, portal hypertension versus control, 16.8 +/- 0.7 vs 11.8 +/- 0.7 mm Hg, P less than 0.0001). Although liquids were emptied in an exponential manner and solids in a linear fashion, gastric emptying of both meals was more rapid in the experimental rats. Ten minutes after the liquid meal, more than 50% of the meal had emptied from the stomachs of portal hypertensive rats while only one third of the meal had cleared in the control group (P less than 0.02). Gastric emptying of the solid meal was significantly accelerated in experimental rats at 60 and 120 min (percent meal remaining: portal hypertension versus control, 41.9 +/- 4.0 vs 55.4 +/- 3.5 and 21.5 +/- 4.9 vs 32.6 +/- 4.3, P less than 0.05). Stomachs of portal hypertensive animals were heavier (P less than 0.009) and histologic examination revealed submucosal edema. Thus, a possible mechanism of the disrupted gastric motor function in portal hypertension is decreased gastric wall compliance secondary to edema.

Animals↗
PubMed1990

The effect of mesenteric venous hypertension on gut motility and absorption.

The effects of portal hypertension on gut function may be mediated by venous congestion and altered circulating levels of enteric hormones and neuropeptides. We designed this study to determine the effects of chronic intestinal venous hypertension (VHT), in isolation, on gut motility and absorption. In 10 dogs, a 20- to 25-cm loop of jejunum was isolated from the fecal stream, but myoneural continuity was maintained with the proximal bowel by a seromuscular bridge. In 5 dogs, VHT was created in the loop by a fixed stenosis of its venous drainage; a sham procedure was performed in a further 5 animals. Serosal monopolar electrodes were placed in all animals. Absorptive function and myoelectrical activity were studied over a 4-week period. Venous hypertension was achieved and sustained in the VHT animals; loop vein pressures for VHT vs control in cm H2O (means +/- SEM) are: initial--29.8 +/- 1.8 vs 7.5 +/- 0.4 (P less than 0.01), and at 4 weeks--17.6 +/- 6.88 vs 7.3 +/- 0.2 (P less than 0.01). Absorption of Na+, Cl-, glucose, and water was impaired in VHT loops. Normal patterns of fasting and postprandial myoelectrical activity were preserved in the VHT animals. We conclude that chronic VHT, in the absence of portosystemic shunting, results in impaired absorption of water, glucose, and electrolytes without any change in intestinal motility.

Animals↗
PubMed1990

Definitive therapy for variceal bleeding: a personal view.

Definitive therapy for variceal hemorrhage has evolved during the past half century. Only completely decompressing shunts (nonselective shunts) were available before 1967. Additional options now include selective shunts, devascularization procedures, endoscopic sclerotherapy, pharmacotherapy, and hepatic transplantation. Although drug treatment is experimental at the present time, the remaining therapeutic options are applicable to various subgroups of patients and in certain clinical settings. At the University of Nebraska, patients with variceal bleeding are first grouped based on their candidacy for transplantation. Transplantation candidates with advanced (Child's class C) or symptomatic liver disease undergo transplantation as soon as possible. Future transplantation candidates with stable, asymptomatic liver disease undergo either long-term sclerotherapy or a distal splenorenal shunt if sclerotherapy fails or if they have poor access to tertiary medical care. These patients are carefully monitored so that they can undergo transplantation before they become high-operative risks. Patients who are not candidates for transplantation receive chronic variceal sclerotherapy as initial therapy so long as shunt surgery is readily available if sclerotherapy fails. When surgery is indicated, the distal splenorenal shunt is preferred to nonselective shunts because several controlled and uncontrolled series have demonstrated a lower frequency of encephalopathy after selective variceal decompression.

Acute Disease↗
PubMed1990

Nonoperative emergency treatment of variceal hemorrhage.

The nonoperative management of acute variceal hemorrhage can control acute hemorrhage and allow stabilization of the patient prior to definitive therapy to prevent further bleeding episodes. Balloon tamponade, endoscopic sclerotherapy, and pharmacotherapy can stop acute variceal bleeding. Endoscopic sclerotherapy has the highest reported success rate, decreases the incidence of early rebleeding, and is the recommended first method to control bleeding.

Balloon Occlusion↗
PubMed1990

Liver transplantation for variceal hemorrhage.

At the present time, liver transplantation must be considered among the treatment options for patients with variceal hemorrhage. For a significant percentage of variceal bleeders throughout the world, however, transplantation is not a viable option either because the patient is not an appropriate transplant candidate or because of the etiology of the patient's portal hypertension. Sclerotherapy and portosystemic shunts remain the mainstay of therapy for these patients. The survival rates with liver transplantation are superior to those reported for other therapies for variceal hemorrhage in patients who have moderate or severe liver disease in addition to variceal hemorrhage. Child's C patients whose variceal hemorrhage is controlled medically should be evaluated for transplantation and receive chronic sclerotherapy while they wait on the transplant list. If the variceal hemorrhage cannot be controlled medically in a transplant candidate, then the patient should undergo an emergency shunt procedure. The shunt of choice is a large-bore H-graft mesocaval or mesorenal shunt. This shunt effectively controls the acute hemorrhage, is relatively simple to perform, does not adversely impact on the subsequent liver transplant, and can simply be ligated after the transplant is completed. Patients who experience variceal hemorrhage as the only manifestation of their liver disease should be treated initially with endoscopic sclerotherapy. For that small group of patients who are either not candidates for sclerotherapy or who rebleed despite sclerotherapy, the choice of shunt or transplantation is presently a difficult one, because both therapies provide excellent results in this group of patients. The choice of therapy should be made on an individual basis and only after consultation with both transplant and shunt surgeons. If a shunt is chosen, we prefer the DSRS because it maintains hepatic portal perfusion in many patients and does not require dissection of the porta hepatis. The management of patients with a prior portosystemic shunt at the time of transplantation depends on the type of shunt and the duration of time between the shunt and the transplant. Shunts not involving the hepatic hilum have little adverse impact on the performance of the transplant. There are insufficient data to assess accurately the effect of a prior portacaval shunt on the transplant. However, our clinical experience and that of other transplant groups indicate that the transplantation of these patients is technically more difficult than that of patients with shunts not involving the hilum. With the availability of other shunting procedures that do not involve extensive dissection of the hepatic hilum, there is little role for either end-to-side or side-to-side portacaval shunts in patients who are potential liver transplant candidates.(ABSTRACT TRUNCATED AT 400 WORDS)

Esophageal and Gastric Varices↗
PubMed1990

The impact of extended preservation on clinical liver transplantation.

The introduction of UW solution into clinical transplantation has permitted extended cold storage preservation of the liver. Over a 46-month period, we have performed 308 orthotopic liver transplants (266 primary, 42 retransplants) in 266 recipients. Our experience is divided into cold-storage preservation in Eurocollins (163 transplants in 140 recipients) and UW (145 transplants in 131 recipients) solutions. Donor and recipient factors were comparable between the two groups. The use of UW solution has permitted an increase in the mean preservation time from 5.2 +/- 1.0 [EC] to 12.8 +/- 4.3 [UW] hr (P less than 0.001). The mean total operating time was reduced but intraoperative blood loss was unchanged with UW preservation. The number of transplants performed during the daytime hours has increased dramatically (21.5% [EC] vs. 71% [UW], P less than 0.001). The incidence of primary nonfunction, hepatic artery thrombosis, 1-month graft survival, and early retransplantation were similar in the 2 groups. Initial allograft function as determined by bile production, histology, and clinical assessment were likewise similar. Mean serum bilirubin, transaminase, and prothrombin levels were virtually identical by 5 days posttransplant. The enhanced margin of safety afforded by extended preservation has increased the capability for distant organ procurement and sharing, minimized organ wastage, and improved the efficiency of organ retrieval. With the relaxation of logistical constraints, our rate of liver import has nearly doubled (20.9% [EC] vs. 39.3% [UW], P less than 0.001). Extended preservation has permitted the development of reduced-size liver grafting (n = 12), resulting in a significant reduction in the number of deaths occurring while awaiting transplantation. Therefore, we advocate the use of UW solution with selective extension of preservation based not only on donor and recipient factors but also on manpower, resource, and logistical considerations.

Adenosine↗
PubMed1990

Comparison of ulcer surgery at a Veterans Administration and University Hospital.

We compared the patient populations and outcome of surgery for peptic ulcer disease in 81 patients at a Veterans Administration Hospital (OVAH) and 97 patients at an affiliated University Hospital (UNH). The surgeons and choice of operation were comparable at both facilities. Patients were similar with respect to severity of ulcer disease, percentage of elderly patients and distribution of comorbid conditions. There were significantly more female patients (45% vs 2%, P less than 0.05), patients less than 40 years old (22% vs 6%, P less than 0.05), and patients with gastric ulcers (27% vs 12%, P less than 0.05) at UNH. Alcoholism was more prevalent at OVAH (57% vs 22%, P less than 0.05). Postoperative morbidity and mortality rates were 27 per cent and 14 per cent at OVAH and 25 per cent and 16 per cent at UNH. These data suggest that quality of care for surgical therapy of ulcer disease at a VA Hospital is comparable to its tertiary care affiliate with a similar patient population.

Adult↗
PubMed1990

Indications and results of shunt operations in the treatment of patients with recurrent variceal hemorrhage.

None of the portasystemic shunts are ideal for all patients with recurrent variceal hemorrhage. Hemodynamic and clinical status should determine the type of shunt selected. Patients with a compatible anatomy, hepatopetal protal flow and controlled ascites are best served by a distal splenorenal shunt. Patients with variceal hemorrhage and medically resistant ascites are candidates for a side-to-side shunt, with consideration being given to an operation that avoids dissection of the porta hepatis. The end-to-side portacaval shunt should be used only in the emergency situation when other options are not available. However, due to the effectiveness of other therapies, such as sclerotherapy, in controlling bleeding, emergency shunts are rarely required. On the basis of the controlled trials of distal splenorenal shunt versus sclerotherapy, the latter is the initial treatment of choice with distal splenorenal shunt used promptly when sclerotherapy fails. Patients who live in remote areas, and noncompliant individuals may be best served with a distal splenorenal shunt as initial therapy.

Esophageal and Gastric Varices↗