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Dive into the research topics where P. R. John is active.

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Featured researches published by P. R. John.


Transplant International | 1995

Biliary complications after paediatric liver transplantation: Birmingham's experience

Christophe Chardot; Daniel Candinas; Darius F. Mirza; Bridget K. Gunson; Suzanne Davison; M. Stephen Murphy; Deirdre Kelly; P. R. John; Paul McMaster; David Mayer; John A. C. Buckels

Abstract Between 1983 and 1992, 112 children underwent liver transplantation. Of 138 grafts, 60 (43.4%) were whole livers, 77 (55.6%) were reduced livers, and 1 (0.7%) was a split liver. Biliary complications (BC) were defined as any abnormality, even minor, related to the biliary tract. Results were analysed with a minimum follow‐up of 9 months. Some 36 grafts (26.1%) in 34 patients (30.4%) presented with BC: bile leaks (17 grafts), biliary obstructions or dilatations (16 grafts), and other complications (3 grafts). Management was mainly surgical with biliary reconstruction via a Roux‐en‐Y loop. Interventional radiology had an increasing role in recent years. BC were associated with a mortality of 1.8% (2/112), a graft loss rate of 4.3% (6/138), and significant morbidity. Among the various factors whose association with BC was studied, the date of transplantation, the use of reduced grafts and the use of gallbladder conduits appeared to be the main determining factors for BC. From multivariate analysis the use of reduced grafts emerged as the most important factor in reducing BC. We therefore conclude that BC are associated with significant morbidity, but general improvements in both surgical and medical management seem to account for better results in recent years.


Transplantation | 2002

Improved technique of portal vein reconstruction in pediatric liver transplant recipients with portal vein hypoplasia.

Andrew Mitchell; P. R. John; David Mayer; Darius F. Mirza; John A. C. Buckels; Jean de Ville de Goyet

Background. Children with small or hypoplastic portal veins represent a challenge for liver transplantation. Graft loss of up to 70% has been reported in these patients in the past. A variety of techniques has been used in both cadaveric and living related transplants in an effort to overcome this problem. Variability arises as to whether to use a vascular graft and where on the portal system to attach the graft. Method. We present our usage of a simple and straightforward interposition iliac vein allograft fashioned in a manner to achieve large anastomotic cross-sectional area on the confluence of the superior mesenteric/splenic veins. The procedure also overcomes problems of graft vein/portal vein size mismatch in the cases where liver and vein grafts are procured from much larger donors. Results. A total of 14 children presented with hypoplastic portal vein (diameter<5 mm), of a total of 30 consecutive patients requiring cadaveric liver transplants, and benefited from this technique. Median recipient age was 10.5 months. Revascularization times ranged from 22 to 43 min with a mean of 33 min. All patients are alive and well at a mean follow-up of 329 days (10 months). All liver grafts are well and functioning. No portal vein problem was detected. Conclusion. Results from this technique are clearly encouraging. Because portal vein hypoplasia is a common problem in pediatric transplant candidates, we believe this alternative technique is of interest and should be added to the transplant surgeon’s armamentarium.


Journal of Pediatric Gastroenterology and Nutrition | 2006

Management of end-stage central venous access in children referred for possible small bowel transplantation.

Af Rodrigues; I. D. M. Van Mourik; Khalid Sharif; David J. Barron; J. V. De Giovanni; J. Bennett; P. Bromley; Susan Protheroe; P. R. John; J de Ville de Goyet; S. V. Beath

The 3-year survival after small bowel transplantation (SBTx) has improved to between 73% and 88%. Impaired venous access for parenteral nutrition can be an indication for SBTx in children with chronic intestinal failure. Aim: To report our experience in management of children with extreme end-stage venous access. Subjects: The study consisted of 6 children (all boys), median age of assessment 27 months (range, 13-52 months), diagnosed with total intestinal aganglionosis (1), protracted diarrhea (1), and short bowel syndrome (4), of which gastroschisis (2) and malrotation with midgut volvulus (2) were the causes. All had a documented history of more than 10 central venous catheter insertions previously. All had venograms, and 1 child additionally had a magnetic resonance angiogram to evaluate venous access. Five of 6 presented with thrombosis of the superior vena cava (SVC) and/or inferior vena cava. Methods: Venous access was reestablished as follows: transhepatic venous catheters (5), direct intra-atrial catheter via midline sternotomy (4), azygous venous catheters (2), dilatation of left subclavian vein after passage of a guide wire and then placing a catheter to reach the right atrium (1), radiological recanalization of the SVC and placement of a central venous catheter in situ (1), and direct puncture of SVC stump(1). Complications included serous pleural effusion after direct intra-atrial line insertion, which resolved after chest drain insertion (1), displacement of transhepatic catheter needing repositioning (2), and SVC stent narrowing requiring repeated balloon dilatation. Outcome: Four children with permanent intestinal failure on assessment were offered SBTx, 3 of which were transplanted and were established on full enteral nutrition; the family of 1 child declined the procedure. In the remaining 2 children in whom bowel adaptation was still a possibility, attempts were made to provide adequate central venous access as feeds and drug manipulations were undertaken. One of them received liver and SBTx nearly 3 years after presenting with end-stage central venous access, because attempts to achieve independence from parenteral nutrition had failed. The other child died immediately after a transhepatic venous catheter placement, possibly from a nutritional depletion syndrome as no physical cause of death was found. Direct intra-atrial catheters in transplanted children proved to be adequate for the management of uncomplicated transplantation, although the usual infusion protocol had to be modified considerably, and the lack of access would have been critical if massive blood transfusion had been required during the transplant procedure. Conclusion: It was possible to reestablish central venous access in all cases. However, this was time consuming and difficult to assemble a skilled team consisting of one of more: surgeon, cardiologist, interventional radiologist, and transplant anesthetist. Small bowel transplantation is easier and safer with adequate central venous access, and we advocate liaison with an SBTx center at an early stage.


Pediatric Radiology | 2003

Congenital, solitary, large, intrahepatic arterioportal fistula in a child: management and review of the literature.

Nagappan Kumar; Jean de Ville de Goyet; Khalid Sharif; Patrick McKiernan; P. R. John

Abstract. Congenital intrahepatic arterioportal fistula (APF) is a rare condition. In most cases, the symptoms and complications develop during infancy. We report here the incidental finding of a large and solitary congenital APF in a 13-year-old boy, with subsequent related clinical complications. At angiography, an APF connecting the left hepatic artery and the left branch of the portal vein (PV) was demonstrated with reversed flow in the left and main PV. The fistula was successfully occluded, in a single embolisation session, using an Amplatzer occlusion device. This was associated with immediate restoration of normal hepatopetal flow in the PV and followed by resolution of the clinical signs of portal hypertension. This patient is the oldest child with congenital intrahepatic APF to be reported. We emphasise the interest of using a large device (Amplatzer) to occlude a solitary large APF in a single session and, more importantly, to avoid other possible complications related to embolisation.


Pediatric Radiology | 1997

Power Doppler ultrasound appearances of neonatal ischaemic brain injury

David M. Steventon; P. R. John

Following neonatal ischaemic brain injury, irregular vessels increase in size owing to luxury perfusion. These may be demonstrated by conventional colour flow Doppler (CFD) imaging at the periphery of the infarcted area. We present a case in which power Doppler imaging (PDI) was performed in addition to CFD in a neonate with unexplained seizures and which proved more sensitive than CFD in demonstrating luxury perfusion. Ultrasound appearances were compared with those seen on cranial CT. PDI can be a useful adjunct to conventional CFD examination of the neonatal brain in cerebral infarction.


Pediatric Radiology | 1997

Technical aspects of insertion and removal of an inferior vena cava IVC filter for prophylactic treatment of pulmonary embolus

Pl Khong; P. R. John

Abstract We report the successful insertion and subsequent retrieval of a Gunther-Tulip vena cava filter in a patient with an anomalous left-sided inferior vena cava, who developed a right ilio-femoral venous thrombosis prior to planned surgical resection of a right femoral osteosarcoma. The indication was for short-term prophylaxis against pulmonary embolism during manipulative leg surgery.


Pediatric Radiology | 1998

Intervention for pleural effusions and ascites following liver transplantation

Victor A. Adetiloye; P. R. John

Background. Small volumes of fluid in the pleural and peritoneal cavities are common after paediatric liver transplantation. Occasionally, larger fluid collections develop and need intervention by aspiration or insertion of a drain. Objective. To assess the incidence of moderate and large pleural and peritoneal fluid collections following paediatric liver transplantation, the need for intervention and the outcome following radiological and non-radiological treatment, with the ultimate objective of recommending a treatment protocol for such post-operative fluid collections. Materials and methods. A total of 184 consecutive liver grafts in 164 children were reviewed. Results. Of 184 grafts, 31 (16.8 %) developed excessive fluid collections requiring intervention (19 pleural effusions, 8 ascites and 4 effusions and ascites). The effusions were first diagnosed between days 1 and 44 after transplant and the ascites between days 1 and 14. The initial diagnosis was made radiologically in 21 (91 %) of 23 pleural effusions and in 10 (83 %) of 12 ascites. No identifiable cause or association was seen in 18 (58 %) of 31 cases. The mean duration of the pleural effusions and ascites, from onset of treatment to resolution, ranged from 33 ± 42 days (SD) to 35 ± 48 days and from 36 ± 47 days to 39 ± 46 days respectively. Comparison of the modes of interventional treatment (i. e. unguided, radiological and surgical) showed no statistically significant difference in the outcome of the management. Conclusions. Post-transplantation pleural effusions and ascites requiring intervention are often without definite cause. They are more common with reduced grafts, but this cannot completely explain the occurrence or the protracted duration of accumulation in spite of combined interventional management. The outcome of treatment is not significantly influenced by the mode of intervention except in cases where surgical intervention is indicated. Patients could be managed effectively without resorting to chronic outpatient aspiration. US contributed significantly in the initial and follow-up evaluation of these patients, even in cases of pleural effusions, and we would recommend greater use of US in place of radiographs to reduce the radiation burden when fluid collections are protracted.


Pediatric Radiology | 1996

Imaging of biliary complications following paediatric liver transplantation

James F. Griffith; P. R. John

Biliary complications (BC) are well recognised following paediatric liver transplantation. We reviewed retrospectively 169 consecutive liver transplants performed in 139 children. BC occurred in 36/169 grafts (21 %) in 35/139 patients (25 %). Biliary obstruction was present in 18/169 grafts (11 %), biliary leakage in 14/169 grafts (8 %) and a combination of obstruction and leakage was present in 4/169 (2 %) grafts. BC were as likely to present radiologically as they were with either clinical and/or biochemical abnormalities. Most BC (26/36, i. e. 72 %) occurred in the first 2 weeks following transplantation. Ultrasound and cholangiography were the principle imaging modalities used for detection of these complications. False negative ultrasound examinations occurred in three patients with biliary obstruction and in three patients with biliary leakage. False negative cholangiograms occurred in two patients with biliary leakage. Ultrasound is important in the post-operative surveillance of paediatric liver transplants, with cholangiography having a complementary role in those with BC.


Journal of Pediatric Gastroenterology and Nutrition | 2002

Inferior vena cava occlusion and protein-losing enteropathy after liver transplantation in children.

Way Seah Lee; P. R. John; Patrick McKiernan; Jon De Ville De Goyet; Deirdre Kelly

Protein-losing enteropathy (PLE) in children can occur as a result of protein loss from abnormal intestinal lymphatics or across an inflamed or abnormal intestinal mucosal surface (1). Protein-losing enteropathy secondary to abnormalities of intestinal lymphatics, or intestinal lymphangiectasia, may be primary or acquired (1). Important physiologic mechanisms in the pathogenesis of PLE caused by abnormal lymphatic protein loss include 1) intraatrial obstruction of the systemic venous return, leading to high constant systemic venous pressure and impeding the lymphatic flow into the superior vena cava, for example, after Fontan procedure (2,3); 2) damage to the thoracic duct; and 3) obstruction of hepatic venous outflow, such as in Budd-Chiari syndrome (4). Proteinlosing enteropathy caused by obstruction of hepatic venous outflow after liver transplantation has been reported previously (4). There are no previous reports of PLE associated with inferior vena cava obstruction after liver transplantation. We report two children in whom PLE developed with and without intestinal lymphangiectasia because of inferior vena cava obstruction after liver transplantation.


Pediatric Radiology | 1998

US demonstration and diagnosis of the midaortic syndrome

William M. Adams; P. R. John

Abstract The midaortic syndrome is a rare entity, typically presenting with hypertension, refractory to treatment. The diagnosis is usually made by arteriography. We report a child in whom the diagnosis was made by ultrasound, confirmed by arteriography and successfully treated by balloon dilatation.

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Patrick McKiernan

Boston Children's Hospital

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Deirdre Kelly

Boston Children's Hospital

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Khalid Sharif

Boston Children's Hospital

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S. V. Beath

Boston Children's Hospital

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Susan Protheroe

Boston Children's Hospital

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William M. Adams

Boston Children's Hospital

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J de Ville de Goyet

Université catholique de Louvain

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