OA20 Pneumatosis intestinalis with spontaneous pneumoperitoneum in a patient with systemic sclerosis-myositis overlap syndrome: a case report and review of the literature

Introduction/Background

Pneumatosis intestinalis (PI) is characterised by submucosal and/or subserosal collections of free gas, forming cystic lesions within the gastrointestinal (GI) tract, most commonly seen in the small intestine but it can also involve large intestine or the stomach. PI is idiopathic in about 15% of cases but the majority is secondary to conditions such as autoimmune, infectious, inflammatory, pulmonary, drug and/or traumatic aetiologies. PI is a rare and usually benign complication of systemic sclerosis (SSc), and most patients are relatively asymptomatic. Its pathogenesis is likely to involve complex interplay of mechanical, biochemical, bacterial and/or drug factors.

Description/Method

A 67-year-old man with SSc-myositis overlap syndrome for over nine years on long term Mycophenolate mofetil 500mg BD and Prednisolone 8mg OD presented acutely unwell with worsening abdominal pain, bloatedness, distension, intermittent bloody diarrhoea and vomiting for three weeks. He was afebrile but slightly hypotensive and tachycardic. His abdomen was distended with mild generalised tenderness but soft and regular bowel sounds were audible. There were no palpable organomegaly, guarding, rebound tenderness or other signs of peritonism.

He had raised serum lactate at 3.1 and pre-renal acute kidney injury secondary to GI losses and reduced oral intake but his full blood count, liver blood tests, serum amylase, calcium profile, blood glucose, venous blood gas and C-reactive protein were all within normal range. His coeliac screen (IgA tTG) was normal. He tested positive for ANA Hep2 (speckled) but negative for ENA, anti-dsDNA and anti-centromere antibodies. His other SSc presentations include Raynaud’s phenomenon and diffuse scleroderma. His contrast-enhanced CT abdomen and pelvis on admission displayed extensive pneumatosis changes, moderately dilated small bowel loops and pneumoperitoneum. There are prominent atherosclerotic changes seen in aorta and its major branches with associated narrowing but there is no acute thrombotic occlusion seen in the main-stem superior or inferior mesenteric arteries or their major branches.

The patient was managed conservatively with bowel rest, intravenous fluids and antibiotics, and was referred for palliative care as surgical exploration was deemed inappropriately risky given his underlying ischaemic heart disease and impaired cardiac reserve. He was discharged home following a short hospital stay with anticipatory medications and a short course of Rifaximin followed by monthly antibiotic cycling with Co-amoxiclav, Metronidazole and Ciprofloxacin. He made a surprisingly excellent recovery on the antibiotics and his repeat CT scans at 11 weeks showed complete resolution of the pneumatosis intestinalis.

Discussion/Results

PI with or without pneumoperitoneum is a rare gastrointestinal complication of SSc characterised by numerous intramural air-filled cysts within the GI tract. In spite of its usually extensive involvement of the GI tract, this condition generally runs a benign course and is managed conservatively in most cases. The development of PI in SSc is multifactorial, including mechanical (increased luminal pressure allowing gas to permeate into submucosal space through mucosal breach), biochemical (excessive hydrogen production via fermentation processes in gut), overgrowth of gas-producing bacteria and drugs such as corticosteroids that could possibly cause intestinal mucosa atrophy and breakdown.

Symptoms of PI can include diarrhoea, constipation, abdominal pain, rectal bleeding and mucous discharge. CT scan has high sensitivity and is the best diagnostic modality for PI. The treatment of PI is based on the severity of symptoms. The underlying cause of PI should be appropriately addressed and managed in all cases. Patients with asymptomatic PI need no further treatment but regular clinical review and monitoring are advisable. Conservative management is preferable to surgical intervention after careful exclusion of acute surgical causes or complications such as bowel perforation, ischaemia or obstruction. For patients with mild symptoms who do not require hospitalisation, antibiotics and elemental diet are recommended. However, for acutely unwell patients with moderate to severe symptoms, hospitalisation is usually required for bowel rest or decompression, fluid and electrolyte replacements, elemental diet or parenteral nutrition, antibiotics, high concentration oxygen, hyperbaric oxygen therapy or octreotide infusion.

Our patient was managed conservatively as he did not exhibit any clinical signs of peritonism or bowel ischaemia and surgical interventions were deemed too risky given his underlying cardiac status. He was treated with and has responded well to cycling oral antibiotics for small intestinal bacterial overgrowth which was thought to be contributory to his PI.

Key learning points/Conclusion

This case report illustrates that PI could be a rare gastrointestinal complication and presentation of SSc-myositis overlap syndrome, therefore clinicians should be aware of this uncommon manifestation of SSc. Other more common differentials such as inflammatory bowel disease, infections or even an underlying malignancy must be thoroughly assessed for and excluded.

Pneumoperitoneum in the context of SSc-associated PI is generally benign in nature, spontaneous i.e. non-surgical and it occurs as a result of spontaneous rupture of the air-filled cysts within the gastrointestinal walls, rather than due to true bowel perforation. PI with or without pneumoperitoneum in patients with SSc is usually asymptomatic and only discovered incidentally on imaging or screening endoscopy. However, patients can present with more acute symptoms such as generalised abdominal pain/tenderness, distension and/or vomiting. These clinical presentations and imaging findings may simulate acute surgical abdomen such as bowel perforation and/or ischaemia, leading to diagnostic dilemma and unnecessary or inappropriately risky surgical interventions. Therefore, a precise diagnosis of PI and correct interpretation of its clinical significance are crucial, since PI is generally managed conservatively with favourable response.

Surgical treatment is generally not preferred because GI involvement in SSc is almost always extensive, and operative manipulation is likely to result in post-operative complications. However, emergency laparotomy should be considered in patients who exhibit signs of peritonism or bowel ischaemia and therefore timely involvement of surgeons and multidisciplinary team is essential.

AB0589 TOCILIZUMAB FOR GIANT CELL ARTERITIS: BASELINE AND TWELVE MONTH AUDIT DATA FROM THE UK BRISTOL AND BATH MULTIDISCIPLINARY MEETING

Background

Giant Cell Arteritis (GCA) is a systemic vasculitis involving large and medium-sized blood vessels. Treatment is with high dose glucocorticoids. Steroid-sparing agents and Tocilizumab (TCZ) are used for refractory or relapsing cases. NHS England requires all GCA patients to be discussed in a regional multidisciplinary team meeting (MDT) prior to commencing TCZ. TCZ has only been permitted for a maximum of one year; this time limitation was extended during the Covid-19 pandemic (1). The monthly virtual Bristol and Bath regional MDT started in November 2018.

Objectives

We aimed to review: 1) Baseline data on all patients referred to the Bristol and Bath TCZ for GCA MDT, including demographics, clinical presentation and previous steroid-sparing agents used and 2) 12 month follow up data including number of completions, adverse effects, and flares on treatment.

Methods

The TCZ MDT referral proforma, adapted from the NHS England Blueteq approval form, was reviewed for all patients referred. 12 month follow up data was obtained from clinic letters.

Results

Baseline data

Thirty-eight cases were referred between November 2018 and September 2021. Of these, 31 were approved for TCZ usage; 100% fulfilled the criteria for either refractory (n=11) or relapsing (n=20) disease. Mean age was 74 years and 74.2% were female. Average disease duration was 161.5 days for the refractory and 827.3 days for the relapsing group.

77.4% had cranial GCA, 48.4% had large vessel involvement, 45.2% had visual symptoms and 25.8% had ischaemic visual loss. The positive investigations were PET-CT (48.4%), temporal artery ultrasound (41.9%) and temporal artery biopsy (32.3%).

64.5% had trialled a steroid-sparing agent at time of referral (61.3 % methotrexate, 9.7% azathioprine, 6.5% leflunomide), 35.5% had received intravenous methylprednisolone and 58% were receiving greater than 40mg prednisolone at the time of referral.

Glucocorticoid adverse effects of osteoporosis, weight gain, cataracts and hypertension were each seen in 19.4%; whilst diabetes, neuropsychiatric symptoms and sleep disturbance were each reported in 16.1%.

Those with ocular involvement tended to be referred earlier than those without (478.2 days vs 648.1 days), were referred on higher doses of glucocorticoids (71.4% vs 47.1% on ≥ 40mg) and had less steroid-sparing agents prior to referral.

Follow up data

In December 2021, a follow-up audit revealed 14/31 patients had completed at least 12 months of tocilizumab; 5 of these had had an extension under Covid-19 exceptional guidance (mean duration of 5.2 months). Of the remaining 17: 3 patients had stopped early (1 death, 1 moved away, 1 due to adverse effects of headache and gastro-intestinal side effects), 4 had not started tocilizumab and 10 had not completed 12 months of treatment at that point.

Adverse events in the 14 patients at 12 months included: liver abnormalities (2/14; 14.3%), neutropenia (2/14; 14.3%), thrombocytopaenia (1/14; 7.1%), soft tissue infections (3/14; 21.4%), urinary tract infection (1/14; 7.1%) and lipid derangement (4/14 28.6%). One case of GCA relapse occurred on TCZ (mild headache and raised inflammatory markers settled on small increase in prednisolone). After 12 months, mean prednisolone dose was 3mg (range 0-15mg).

Conclusion

All patients approved for Tocilizumab in the GCA MDT fulfilled NHS England criteria for either relapsing or refractory disease. The majority of cases had cranial disease, but almost half had either ocular or large vessel involvement, reflecting a severe spectrum of disease. Cases showed a high burden of glucocorticoid toxicity. Follow up data suggests that TCZ was effective in allowing glucocorticoid weaning and disease control, but with some adverse effects. Future work to follow up patients after stopping Tocilizumab would be informative, as the twelve month limitation on treatment is likely to be re-instated.

References

[1]https://www.england.nhs.uk/coronavirus/publication/tocilizumab-for-giant-cell-arteritis-gca-during-the-covid-19-pandemic-rps-2007/

Disclosure of Interests

Chandrin N. R. Jayatilleke: None declared, Aishwarya Anilkumar: None declared, Shalini Janagan: None declared, Robert W Marshall: None declared, Sarah Skeoch: None declared, Catherine Guly Grant/research support from: Eli Lilly and Company - paid consultant for a research trial, Fang En Sin: None declared, Keziah Austin: None declared, Laith Al-Sweedan: None declared, Alexandra Bourn: None declared, Lynsey Clarke: None declared, Harsha Gunawardena: None declared, Baashar Boyce: None declared, Sally Knights: None declared, John D Pauling: None declared, Elizabeth Reilly: None declared, Timothy D Reynolds: None declared, Sarah Villar: None declared, Joanna C Robson: None declared

P293 Tocilizumab for refractory or relapsing giant cell arteritis: audit data from the Bristol and Bath regional multidisciplinary meetings 2018-2021

Background/Aims

Giant cell arteritis (GCA) is a systemic vasculitis involving large and medium-sized blood vessels. Patients can present with cranial, ocular or large vessel (LVV-GCA) involvement. Treatment is with high dose glucocorticoids. Steroid-sparing agents and tocilizumab (TCZ) are used for refractory or relapsing cases. NHS England requires all GCA patients to be discussed in a regional multidisciplinary team meeting (MDT) prior to commencing TCZ. We reviewed the case mixture of patients referred to the Bristol and Bath regional MDT.

Methods

The Bristol and Bath regional MDT started in November 2018 and runs monthly. A referral proforma was designed, adapted from the NHS England Blueteq approval form for TCZ in GCA (definitions of refractory and relapsing disease), with tick boxes for clinical features, investigations, treatment, glucocorticoid adverse events and a free text clinical vignette. All referral proformas were reviewed.

Results

Audit data from all cases referred, between November 2018 and September 2021, were analysed. 38 cases of GCA were discussed with 31 cases approved for TCZ usage. Of the approved, 100% fulfilled the criteria for either refractory (n = 11) or relapsing (n = 20) disease. Mean age of approved cases was 74 years with three quarters being female (74.2%). Average disease duration was 161.5 days for the refractory group and 827.3 days for the relapsing group. Over three quarters of cases (77.4%) had cranial GCA, 48.4% had LVV-GCA, 45.2% had visual symptoms (reduction in visual acuity, blurring or diplopia) and 25.8% had ischaemic visual loss. The positive investigations were PET-CT (48.4%), temporal artery ultrasound (41.9%) and temporal artery biopsy (32.3%). Almost two-thirds (64.5%) had previously had a steroid-sparing agent (61.3 % methotrexate, 9.7% azathioprine, 6.5% leflunomide), one third (35.5%) had received intravenous methylprednisolone and more than half (58%) were receiving greater than 40mg prednisolone at the time of referral. Common glucocorticoid adverse effects (each seen in 19.4% of cases) included osteoporosis, weight gain, cataracts or hypertension, whilst diabetes, neuropsychiatric symptoms or sleep disturbance were each reported in 16.1% of cases. The majority of patients with ocular involvement had cranial symptoms (71%). Patients with ocular involvement tended to be referred earlier than those with no ocular involvement (478.2 days vs 648.1 days), were on a higher dose of glucocorticoids at time of referral (71.4% vs 47.1% on more than 40mg) and had fewer steroid-sparing agents prior to referral.

Conclusion

All patients approved for TCZ in the GCA MDT fulfilled NHS England criteria for either relapsing or refractory disease. The majority of cases had cranial disease, but almost half had either ocular or large vessel vasculitis involvement, reflecting a severe spectrum of disease. Cases showed a high burden of glucocorticoid toxicity. Patients with ocular involvement were referred slightly earlier with less use of other steroid sparing treatments prior to TCZ in our cohort.

Disclosure

C. Jayatilleke: None. S. Janagan: None. R. Marshall: Other; Has received sponsorship from UCB Pharma to attend educational conferences in the last 2 years. S. Skeoch: None. C.M. Guly: None. F. En Sin: None. L. AL Sweedan: None. A. Anilkumar: None. K. Austin: None. A. Bourn: None. L. Clarke: None. H. Gunawardena: None. A. Johnson: None. S. Knights: None. J.D. Pauling: None. E. Reilly: None. T.D. Reynolds: None. S. Villar: None. J.C. Robson: None.

P290 Baseline monocyte count may help make a diagnosis of giant cell arteritis: results of routinely collected audit data from two centres

Background/Aims

Giant cell arteritis is a large vessel vasculitis classically affecting the head and neck. If untreated it leads to permanent vision loss. Diagnosis of GCA is based on clinical judgement of the likelihood of GCA combined with blood tests, imaging and/or temporal artery biopsy. Biopsy is considered the gold standard, but access has been restricted at many centres during the pandemic. It is recognised that some patients will have a negative ultrasound but still deemed to have GCA based on the clinical history and physical findings. In a previous audit at Yeovil District Hospital, we evaluated factors associated with biopsy-proven GCA to explore how routine tests help guide diagnosis, particularly in cases where initial imaging is negative and biopsy is unavailable. This audit found that the baseline monocyte count had good diagnostic accuracy compared to classical inflammatory markers and clinical parameters (area under the curve [AUC] 0.81, 95% confidence interval [CI] 0.67-0.95, p = 0.0034). Although novel, this finding involved a small number of patients and requires further investigation. We aimed to repeat the audit in a larger cohort and investigate blood biomarkers, including monocytes, in GCA patients as defined by physician diagnosis.

Methods

At the Royal National Hospital for Rheumatic Diseases, data were collected retrospectively on patients that were referred between 01/2020 and 09/2021 from hospital records, the GP referral, and pathology systems. A positive diagnosis of GCA was determined by presentation, inflammatory response, vascular imaging and clinical course, and was confirmed by a rheumatologist. Sensitivity, specificity and ROC analysis were calculated for each biomarker, including monocyte count, platelets, CRP, and plasma viscosity (PV).

Results

301 referrals were made to the GCA clinic over the period audited. 109/301 (36%) were diagnosed with GCA, of which 98/109 (90%) had imaging studies and 62/98 (67%) had had a positive test. 55/301 referrals had already started glucocorticoids before baseline blood monitoring. ROC analysis found monocyte count was predictive of GCA (AUC 0.83, 95%CI 0.77-0.90, p < 0.0001). A cut-off value of ≥ 0.9 x 106/L gave a specificity of > 95% and a positive likelihood ratio (LR) of 10 for a diagnosis of GCA in this cohort. However, monocytes were heavily influenced by glucocorticoids and after ≥1 dose there was a drop in sensitivity of 20%.

Conclusion

In a second, larger cohort of GCA cases, we have again identified monocytes as a potential biomarker of GCA. However, they appear to be highly sensitive to glucocorticoids and their use as a biomarker may be limited to glucocorticoid-naïve patients. A prospective research study is now being planned to take these findings further.

Disclosure

B. Mulhearn: None. J. Ellis: None. T. Somoskeoy: None. A. Bourn: None. S. Knights: None. S. Skeoch: None. S. Tansley: None.

P206 Rethinking old biomarkers: novel predictors of giant cell arteritis

Background/Aims 

Giant cell arteritis (GCA) is a large vessel vasculitis mainly affecting the arteries of the head and neck which, if untreated, may lead to permanent vision loss. Glucocorticoids are highly effective at turning off inflammation but come with toxic side effects, making prompt diagnosis essential. There is no gold-standard investigation for GCA. Although specific, temporal artery biopsy (TAB) is only positive in approximately 25% of cases making it problematic as a rule-in diagnostic test. Vascular ultrasound may aid diagnosis but there is a rapid reduction in sensitivity with glucocorticoid use and it is not yet universally available. Diagnosis therefore requires the integration of clinical judgment with blood tests measuring inflammation, imaging, and biopsy. Aims:Identify which components of the history, examination and laboratory findings are most predictive of a positive diagnosis of GCA in the local region of Yeovil District Hospital, and to investigate the usefulness of alternative blood biomarkers.

Methods 

Data was collected from GCA clinic attendances between August 2018 and February 2020 using electronic notes, clinic letters and the pathology system. Predictive values, sensitivity, specificity, and receiver operating characteristic (ROC) curves were calculated for each individual parameter and for groups of parameters.

Results 

Ninety-one patients presented to GCA clinic in the 18 months studied. Median age was 71 and 73% were female. 56 patients with suspected disease went on to have TAB, of which 38/56 (68%) were of adequate length ( > =10mm), and of those, 12/38 (32%) confirmed a diagnosis of GCA. 43/91 (47%) patients were ultimately diagnosed biopsy proven or suspected GCA. Headache was the most common presenting feature (88%) followed by raised ESR (55%), raised CRP (53%), visual disturbance (44%), scalp tenderness (33%), jaw claudication (31%), PMR symptoms (27%) and temporal artery abnormalities (20%). Headache and raised CRP+/-ESR were the most sensitive markers (91% and 100%, respectively). They were, however, the least specific (4% and 36%). Temporal artery abnormality was the most specific finding (81%). ROC analysis revealed that the best-performing biomarkers were monocytes (area under the ROC curve (AUC) of 0.81) and platelets (AUC 0.80), which were superior to jaw claudication, the best-performing classical biomarker (AUC 0.68). Platelets above 450 x 109/L had a specificity of 96% with a likelihood ratio of 10.9. Monocytes above 0.45 x 106/L had sensitivity and specificity of 100% and 67%, respectively.

Conclusion 

GCA cannot be accurately predicted by any single feature. In this cohort, absence of headache with a normal CRP+/-ESR ruled out GCA. Platelets and monocytes performed better than all the classical parameters associated with GCA. Validation of these biomarkers in a larger cohort is now needed to ascertain cut-off points which may help to develop a more accurate method to predict cases of GCA.

Disclosure 

T. Somoskeoy: None. A. Bourn: None. S. Knights: None. B. Mulhearn: None.

Identification and biological characterization of 6-aryl-7-isopropylquinazolinones as novel TRPV1 antagonists that are effective in models of chronic pain

Vanilloid receptor 1 (VR1, TRPV1) is a cation-selective ion channel that is expressed on primary afferent neurons and is upregulated following inflammation and nerve damage. Blockers of this channel may have utility in the treatment of chronic nociceptive and neuropathic pain. Here, we describe the optimization from a high throughput screening hit, of a series of 6-aryl-7-isopropylquinazolinones that are TRPV1 antagonists in vitro. We also demonstrate that one compound is active in vivo against capsaicin-induced hyperalgesia and in models of neuropathic and nociceptive pain in the rat.

Studies on 2'-alpha-C-carboxyalkyl nucleosides and their application to a stereocontrolled nucleobase exchange process

The ability of 2'-alpha-C-carboxyalkyl nucleosides to undergo an unusual two-step stereocontrolled nucleobase exchange process has been investigated. Upon silylation a protected 2'-deoxy-2'-alpha-C-(carboxymethyl)uridine derivative can undergo intramolecular displacement of the uracil base, by the 2'-carboxylic acid group, to form a pentofuranosyl gamma-lactone. Under identical conditions the homologous 2'-deoxy-2'-alpha-C-(carboxyethyl)uridine derivative does not yield the corresponding delta-lactone, but undergoes elimination of uracil to give the corresponding glycal. The pentofuranosyl gamma-lactone is a good substrate for nucleoside synthesis by the Vorbrüggen procedures and undergoes completely stereoselective ring opening with either pyrimidine or purine silylated nucleobases to give novel 2'-C-carboxymethyl beta-nucleosides in moderate to high yield.

Gestational diabetes mellitus. At what time should the postprandial glucose level be monitored?

OBJECTIVE

To compare selected pregnancy outcomes for women with gestational diabetes mellitus (GDM) with management based on testing either 1 hour or 2 hours postprandially according to the ADIPS recommendations.

METHODS

Prospective study of consecutive women referred for the medical management of their GDM. Women were allowed to select whether they would test either 1 hour postprandial with a target glucose of < 8.0 mmol/L or 2 hours postprandial with a target glucose of <7.0 mmol/L. Changes to diet and the introduction and adjustment of insulin therapy were designed to maintain postprandial glucose levels below these targets.

RESULTS

166 women elected to test 1 hour postprandial and 101 elected to test 2 hours postprandial. There were no significant demographic differences between these 2 groups. The fetal birthweight, percentage of women requiring insulin and the total daily dose of insulin were similar in both groups.

CONCLUSIONS

For women with GDM, monitoring either 1 hour or 2 hours postprandially led to similar outcomes. This would suggest that the ADIPS recommendations are equivalent and therefore women can choose the most convenient time for their postprandial monitoring.

Birth weight of women with gestational diabetes

OBJECTIVE

Epidemiological observations have suggested a relationship between type 2 diabetes and a low birth weight. However, there are many confounding variables and problems with retrospective data collection. Women with gestational diabetes mellitus (GDM), who are likely to develop type 2 diabetes in the future, may help clarify these observations.

RESEARCH DESIGN AND METHODS

Consecutive women with GDM (n = 138) were included in the study if they had a singleton pregnancy delivered between 37 and 41 weeks of gestation, if they had themselves been born in the local hospital, and if their own delivery data were available. With respect to their own births, a matched group was obtained by considering the next female delivery of the same gestational age.

RESULTS

For women with GDM, the mean (+/- 1 SD) birth weight was 3,293 +/- 493 g and the ponderal index was 27.0 +/- 2.4. Their values were not significantly different from the matched group, which had a birth weight of 3,315 +/- 460 g and a ponderal index of 27.0 +/- 2.5. After adjusting for the gestational age of delivery, the birth weight of women with GDM did not show a U-shaped distribution.

CONCLUSIONS

After adjustment for the gestational age of delivery, women with GDM do not themselves have either a lower or higher birth weight than a matched group. These data suggest that women with GDM are either not a good surrogate for investigating the relationship between birth weight and type 2 diabetes or that correction for the gestational age of delivery removes the most important confounding variable. It is also possible that modern dietary changes may have altered the relationship.

Measurement of the delivery of dialysis in acute renal failure

BACKGROUND

Recent studies in patients with acute renal failure (ARF) have shown a relationship between the delivered dose of dialysis and patient survival. However, there is currently no consensus on the appropriate method to measure the dose of dialysis in ARF patients. In this study, the dose of dialysis was measured by blood- and dialysate-based kinetic methods in a group of ARF patients who required intermittent hemodialysis.

METHODS

Treatments were performed using a Fresenius 2008E volumetric hemodialysis machine with the ability to fractionally collect the spent dialysate. Single-, double-pool, and equilibrated Kt/V were determined from the pre-, immediate post-, and 30-minute post-blood urea nitrogen (BUN) measurements. The solute reduction index was determined from the collected dialysate, as well as the single- and double-pool Kt/V.

RESULTS

Forty-six treatments in 28 consecutive patients were analyzed. The mean prescribed Kt/V (1.11 +/- 0.32) was significantly greater than the delivered dose estimated by single-pool (0.96 +/- 0.33), equilibrated (0.84 +/- 0.28), and double-pool (0.84 +/- 0.30) Kt/V (compared with prescribed, each P < 0.001). There was no statistical difference between the equilibrated and double-pool Kt/V (P = NS). The solute removal index, as determined from the dialysate, corresponded to a Kt/V of 0.56 +/- 0.27 and was significantly lower than the single-pool and double-pool Kt/V (each P < 0.001).

CONCLUSION

Blood-based kinetics used to estimate the dose of dialysis in ARF patients on intermittent hemodialysis provide internally consistent results. However, when compared with dialysate-side kinetics, blood-based kinetics substantially overestimated the amount of solute (urea) removal.

Prescribed versus delivered dialysis in acute renal failure patients

The current study was designed first to determine separately the prescribed and delivered dose of dialysis and, second, to determine what factors lead to failure to deliver the prescribed dose of dialysis in patients with acute renal failure (ARF). Forty patients, who collectively underwent 136 dialysis treatments, were studied prospectively at two institutions. The results showed that almost half the prescriptions (49%) were for a Kt/V less than 1.2 and, more importantly, nearly 70% of the treatments delivered a Kt/V less than 1.2, the minimally acceptable dose defined in the Dialysis Outcomes Quality Initiative (DOQI) guidelines for chronic hemodialysis (CHD) patients. Patient predialysis weight was the most important variable associated with a low prescribed and delivered dose of dialysis, as well as lack of delivery of the prescribed dose of dialysis. From the statistical model, it is estimated that for every 10-kg increase in predialysis weight, the chance of prescribing or delivering a Kt/V less than 1.2 increased 4.6- and 1.95-fold, respectively. The lower than prescribed blood flow achieved by the temporary catheters and patients not receiving anticoagulation were variables also associated with not receiving the prescribed Kt/V. It is concluded that patients with ARF are prescribed and receive a dose of dialysis that would be considered inadequate for CHD patients. Until the association between dose of dialysis and outcome is better defined, it would be prudent that both the dialysis prescription and the delivery of dialysis to patients with ARF should be performed with the same care and goals as that currently received by patients with end-stage renal disease (ESRD).

Predictive measures of vascular access thrombosis: a prospective study

Malfunction of permanent vascular accesses remains a cause of frequent and costly morbidity in patients receiving chronic hemodialysis (CHD). Several recommendations for routine monitoring of these permanent vascular accesses for incipient failure have been proposed. In this study, multiple indicators of incipient vascular access dysfunction, including "venous" and "arterial" pressures at serial blood flows (200 ml/min, 300 ml/min, and 400 ml/min), percent urea recirculation, Doppler ultrasound, and access blood flow by ultrasound dilution technique were simultaneously evaluated in a total of 220 vascular accesses in 170 chronic hemodialysis patients in two separate study periods (6 months apart). The rate of thrombosis was determined within the subsequent 12 weeks of each study period to assess the short-term predictive power of access thrombosis. During the period of follow-up, there were 34 thrombotic events in 172 polytetrafluoroethylene (PTFE) grafts and only one thrombotic event in 48 arterio-venous fistulas (AVF). Therefore, the statistical analysis was limited to the PTFE grafts. When grafts with thromboses were compared to those without thrombosis by univariate analysis, access blood flow measured either by ultrasound dilution technique (875 +/- 426 ml/min with thrombosis vs. 1193 +/- 677 ml/min without thrombosis, P = 0.001) or by Doppler ultrasound (762 +/- 420 ml/min with thrombosis vs. 1171 +/- 657 ml/min without thrombosis, P = 0.001) were significantly different in the two groups. There was good correlation (r = 0.79, P = 0.0001) between the blood flows determined by both techniques. The grade of stenosis determined by ultrasound was also a statistically significant predictor (P = 0.02). "Venous" and "arterial" pressures were numerically similar and were not statistically different between the accesses that did and those that did not thrombose. When multivariate analysis was used, there was a significantly increased risk of thrombosis only with decreasing access blood flow determined by ultrasound dilution techniques after adjusting for other confounding variables. When the average blood flow of all grafts (1134 ml/min) is considered as the reference access blood flow (relative risk of 1.0), the relative risk of a PTFE thrombotic event within the subsequent 12 weeks was 1.23 at a blood flow 950 ml/min, 1.67 at a blood flow of 650 ml/min and to 2.39 at a blood flow of 300 ml/min. In summary, access blood flow measured by either Dilution or Doppler is a reliable indicator of subsequent short-term thrombosis risk. Other proposed methods of evaluating access dysfunction were not useful in our patients. If simple to use, cost-effective devices to measure dialysis access blood flow become readily available, the measurement of access blood flow will likely become the method of choice for screening of PTFE vascular access dysfunction in hemodialysis patients.

Chemical synthesis of dual-radiolabelled cyclandelate and its metabolism in rat hepatocytes and mouse J774 cells

1. The chemical synthesis of 3,3,5-trimethyl[1-3H]cyclohexanol, 3,3,5-trimethyl[2,3-3H]cyclohexanol and 3,3,5-trimethyl[2,3-3H]cyclohexanyl[1-14C]mandelate (cyclandelate) are described. The ratio of 3H/14C radioactivity in the ester was 27:1. 2. Cultured rat hepatocytes accumulated trimethylcyclohexanol rapidly and excreted its glucuronide into the culture medium. Rat hepatocytes also accumulated cyclandelate rapidly, hydrolysing the ester and excreting trimethylcyclohexanol into the medium. This trimethylcyclohexanol then re-entered the cells and was converted to its glucuronide prior to excretion. 3. In contrast, no hydrolysis of cyclandelate was seen on incubation with J774 cells, a transformed mouse macrophage. 4. Similar differences in hydrolytic activity were seen with microsomal fractions prepared from rat liver and J774 cells. Hepatic microsomes caused a rapid hydrolysis of cyclandelate while no hydrolysis was detectable after incubations of over an hour with J774 microsomes. 5. This difference in hydrolytic activity may have important implications for the action of cyclandelate on cholesterol metabolism in extrahepatic tissues.

A controlled trial of health education in the physician's office

Screening of 6,144 patients in a general practice clinic to assist physician case-finding uncovered 983 (16%) who were uncontrolled hypertensives. Following physician recommendation, 115 patients volunteered for a controlled trial to test the effectiveness of supplementary strategies to the pharmaceutical management of high blood pressure. A study of nonparticipants indicated that about 7% of the practice population was eligible for cardiovascular health education. One group received a health education program, a second was allocated to self-monitor their blood pressure for 6 months, a third group was allocated to both strategies, and the final group, acting as a control, continued to receive their usual care. Physician monitoring of patients continued for the duration of the study and blood pressures decreased in all patients. The study's most important outcome was the joint reduction of blood pressure and medication strength. These were assessed by a "blind" clinician before and after the interventions according to criteria set out in the "stepped-care" approach to management of high blood pressure. People allocated to a health education program conducted in the doctor's common room did twice as well on this measure as those who were not so educated. Daily self-monitoring of blood pressure for 6 months proved to be too much for the majority of those so instructed. It is concluded that the general practice setting remains an important place for health education to prevent cardiac disease and suggestions are made for incorporating this into everyday practice.