Severity of oEsophageal Anastomotic Leak in patients after oesophagectomy: the SEAL score

Background

Anastomotic leak (AL) is a common but severe complication after oesophagectomy. It is unknown how to determine the severity of AL objectively at diagnosis. Determining leak severity may guide treatment decisions and improve future research. This study aimed to identify leak-related prognostic factors for mortality, and to develop a Severity of oEsophageal Anastomotic Leak (SEAL) score.

Methods

This international, retrospective cohort study in 71 centres worldwide included patients with AL after oesophagectomy between 2011 and 2019. The primary endpoint was 90-day mortality. Leak-related prognostic factors were identified after adjusting for confounders and were included in multivariable logistic regression to develop the SEAL score. Four classes of leak severity (mild, moderate, severe, and critical) were defined based on the risk of 90-day mortality, and the score was validated internally.

Results

Some 1509 patients with AL were included and the 90-day mortality rate was 11.7 per cent. Twelve leak-related prognostic factors were included in the SEAL score. The score showed good calibration and discrimination (c-index 0.77, 95 per cent c.i. 0.73 to 0.81). Higher classes of leak severity graded by the SEAL score were associated with a significant increase in duration of ICU stay, healing time, Comprehensive Complication Index score, and Esophagectomy Complications Consensus Group classification.

Conclusion

The SEAL score grades leak severity into four classes by combining 12 leak-related predictors and can be used to the assess severity of AL after oesophagectomy.

Small bowel intussusception and concurrent jejunal polyp with neoplastic transformation: a new diagnosis of Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is a rare hereditary disease characterised by hyperpigmentation of the oral mucosa and gastrointestinal hamartomatous polyps. We report a case of a 27-year-old man who presented with a 5-day history of epigastric pain and rectal bleeding. Computed tomography suggested small bowel obstruction secondary to ileocolic intussusception and an incidental polyp in the mid jejunum. The patient underwent exploratory laparotomy during which right hemicolectomy and small bowel resection were performed. Histology from surgical specimens revealed Peutz-Jeghers polyps, one of which had low-grade dysplasia. This case emphasises that although rare, adults with PJS can present with intussusception. Also illustrated is the extremely rare possibility of concurrent polyps occurring in different parts of the bowel with neoplastic transformation. Intussusception is a challenge to diagnose because the presentation is often non-specific. Clinical history-taking and physical examination along with prompt axial imaging is important for the diagnosis. Careful examination of the bowel and polypectomy during laparotomy may prevent neoplastic transformation and short bowel syndrome.

A single centre evaluation of risk prediction models and imaging modalities in acute appendicitis

INTRODUCTION

Patients with suspected appendicitis remain a diagnostic challenge. The aim of this study was to validate risk prediction models, and to investigate diagnostic accuracy of ultrasonography and computed tomography (CT) in adults undergoing appendicectomy.

METHODS

A retrospective case review was performed of patients aged 16-45 years having an appendicectomy between January 2019 and January 2020 at a tertiary referral centre. Primary outcomes were the accuracy of a high risk appendicitis risk score and ultrasonography and CT imaging modalities compared with histological reports following appendicectomy.

RESULTS

A total of 206 patients (52% female) were included in the study. Removal of a histologically normal appendix was equally likely in men and women (13.1% vs 11.2% respectively, relative risk: 1.17, 95% confidence interval: 0.56-2.44, p=0.674). A high risk appendicitis score correctly identified 84.0% (79/94) of cases in men and 85.9% (67/78) of cases in women. Ultrasonography was reported as equivocal in 85.7% (18/21) of low risk women and 59.0% (23/39) of high risk women. CT correctly detected or excluded appendicitis in 75.0% (6/8) of low risk women and 88.5% (23/26) of high risk women.

CONCLUSIONS

This study suggests that risk prediction models may be useful in both women and men to identify appendicitis. Ultrasonography gave high rates of equivocal results and should not be relied on for the diagnosis of appendicitis. CT is a highly accurate diagnostic tool and could be considered in those at low risk where clinical suspicion remains to reduce negative appendicectomy rates.

Carcinoid heart disease: the role of echocardiography in predicting post-surgical outcomes

Background

Carcinoid heart disease (CHD) often complicates neuroendocrine tumours (NET). The prognosis of CHD without intervention is poor; 3 year survival is estimated at 31%. Surgical valve replacement is the only treatment for CHD, but is associated with high 30-day mortality (10–15%).

Purpose

The aim is to identify pre-operative transthoracic echocardiogram (PTTE) findings that could determine which patients have a high likelihood of post-surgical mortality at 1 year.

Methods

This retrospective observational cohort study recruited 88 patients with a confirmed diagnosis of CHD between 2005–19 at University Hospital Birmingham; 49 (56%) of these were treated surgically. Indications for surgery: stable NET, symptomatic severe valvular dysfunction, progressive RV dilatation or RV dysfunction, no significant comorbidities. All patients underwent a standard PTTE. PTTE parameters assessed: right ventricular (RV) size, RV function (qualitative), TAPSE, RV fractional area change, RV S wave velocity, left ventricular (LV) size, LV ejection fraction and valve velocities. Surgery was performed by a single surgical team with bioprosthetic valve replacements.

Results

Patients were followed up for a median of 15 months (IQR: 6–59) after surgery, during which time there were 33 deaths, giving a median survival time of 30 months (IQR: 7–85). Increasingly severe RV dilatation was significantly associated with shorter survival (p=0.032). The estimated survival rate at three years was 67% in those with normal RV size, compared to 24% in the severe RV group (Figure 1). RV basal diameter was assessed used ROC curve analysis for the outcome of one year survival and returned an area under the curve of 0.66 (SE=0.10). Youden's index identified RV diameter >4.8cm to be the optimal cut-off for identifying high-risk patients. One year mortality rates were 26% (7/27) vs. 75% (9/12) in those with RV basal diameter of ≤4.8 vs. >4.8cm (p=0.006).

Conclusion

A pre-operative right ventricular basal diameter >4.8cm is associated with a near three-fold increase in post-operative mortality at one year. These findings highlight the importance of regular imaging in order to optimise the timing of surgery in patients with CHD.

Figure 1. Kaplan-Meier curve of post-op survival

Funding Acknowledgement

Type of funding source: None

Chest drains – An overview

Chest drains are used in a number of circumstances for the treatment of specific conditions and also for symptomatic relief, and hence insertion of a chest drain can be a life-saving intervention. Therefore, it is imperative that every hospital doctor is familiar with the indications and the principles of safe chest drain insertion. The knowledge of chest drain management following insertion is equally essential. Appropriate chest drain insertion and management underpins the management of chest trauma. Appropriate chest drain management will allow for resolution and management of the underlying clinical condition. This review article outlines the indications, contraindications, and principles of chest drain insertion. Furthermore, it provides an overview of chest drain management and associated complications. Although this review refers to a surgically placed chest drain, the same principles can be applied to a chest drain that is inserted percutaneously.

Effect of Valvular Surgery in Carcinoid Heart Disease: An Observational Cohort Study

CONTEXT

Carcinoid heart disease (NET-CHD) is associated with the development of symptom-limited exercise capacity and high rates of morbidity and mortality.

OBJECTIVE

This study sought to determine the survival, cardiac function, and functional class following surgery.

DESIGN AND SETTING, AND PATIENTS

This was a retrospective observational cohort study between 2005 and 2015 at a European Centre of Excellence for Neuroendocrine Tumours, Queen Elizabeth Hospital Birmingham. England consisting of 62 consecutive patients referred to the NET-Cardiology Service.

INTERVENTIONS

Subjects were assessed at referral using transthoracic echocardiography (with saline contrast) and transesophageal echocardiography, and 77% with confirmed NET-CHD underwent cardiovascular magnetic resonance imaging. Symptomatic patients with concomitant severe valvular dysfunction were referred for surgery with stable NET disease.

MAIN OUTCOME MEASURE

Survival of patients with proven NET-CHD following medical and surgical treatments was measure.

RESULTS

In total, 47/62 patients were diagnosed with NET-CHD. Thirty-two patients (68%) underwent surgery with bioprosthetic valve replacements in all subjects; tricuspid, n = 31; pulmonary, n = 30; mitral, n = 3; and aortic, n = 3. Four patients underwent concomitant coronary artery bypass grafting. There were 4 (13%) early post-operative deaths. One- and 2-y survival rates after surgery were 75 and 69% compared with 45 and 15% in un-operated patients. Post-operatively, functional class was improved (pre-New York Heart Association Classification [NYHA], 2.6 [0.5] vs post-NYHA, 1.7 [1.1]), P < .05, right-ventricular (RV) size was reduced (136 ml/m(2) [25] vs 71 ml/m(2) [7]; P < .01) with preserved RV ejection fraction (61% ± 9 vs 55% ± 10; P = .26).

CONCLUSION

Valve surgery improved functional class and resulted in RV reverse remodelling with improved survival rates at 2 y compared with those not proceeding to operation. These data highlight the importance of close collaboration between NET clinicians, cardiology, and cardiothoracic surgery teams. Early referral can improve functional capacity but more research is needed to define the selection of appropriate candidates and randomized data are needed to define the effect of surgery on prognosis.

Cost-effectiveness of transcatheter aortic valve implantation (TAVI) for aortic stenosis in patients who are high risk or contraindicated for surgery: a model-based economic evaluation

BACKGROUND

Calcific aortic stenosis (AS) is a common valvular heart disease. Patients with severe symptomatic AS typically survive less than 3 years. In such patients, intervention with surgical aortic valve replacement (SAVR) may increase survival. However, in some patients SAVR is associated with a high operative risk and medical management is considered appropriate. Transcatheter aortic valve implantation (TAVI) is a relatively recent technique to avoid the invasiveness of open surgery. This procedure has been used for the treatment of patients with severe AS who are unsuitable for SAVR (because it is too high risk and/or for other reasons such as suffering from porcelain aorta) and is increasingly being considered for other patients.

OBJECTIVES

To determine the cost-effectiveness of TAVI being made available for patients who are high risk or contraindicated for SAVR through a review of existing economic evaluations and development of a model.

DATA SOURCES AND REVIEW METHODS

Bibliographic databases [MEDLINE, EMBASE, The Cochrane Library, Health Technology Assessment (HTA), Database of Abstracts of Reviews of Effects (DARE) and NHS Economic Evaluation Database (EED), Centre for Reviews and Dissemination HTA, DARE and NHS EED], guideline resources, current trials registers, websites/grey literature and manufacturers' websites, and consultation with clinical experts were used to identify studies for the review and information for the model. Databases were searched from 2007 to November 2010. A model was built to assess the cost-effectiveness of TAVI separately in patients suitable and unsuitable for SAVR, together with overall results for the effect of making TAVI available. Substantial deterministic sensitivity analysis was carried out together with probabilistic sensitivity analysis.

RESULTS

No fully published cost-effectiveness studies were found. Modelling patients not suitable for SAVR, the base-case results show TAVI as more costly but more effective than medical management, with an incremental cost-effectiveness ratio (ICER) of £12,900 per quality-adjusted life-year (QALY). The ICER was below £20,000 per QALY for over 99% of model runs in the probabilistic sensitivity analysis. For patients suitable for SAVR, the comparator with TAVI is a mixture of SAVR and medical management. TAVI is both more costly and less effective than this comparator assuming that most patients would receive SAVR in the absence of TAVI. This is robust to a number of assumption changes about the effects of treatment, but sensitive to assumptions about the proportion of patients receiving SAVR in the comparator. If the use of TAVI is extended to include more patients suitable for SAVR, the overall results from the model become less favourable for TAVI.

LIMITATIONS

The modelling involves extrapolation of short-term data and the comparison between TAVI and SAVR is not based on randomised data. More trial data on the latter have been published since the modelling was undertaken.

CONCLUSIONS

The results for TAVI compared with medical management in patients unsuitable for surgery are reasonably robust and suggest that TAVI is likely to be cost-effective. For patients suitable for SAVR, TAVI could be both more costly and less effective than SAVR. The overall results suggest that, if a very substantial majority of TAVI patients are those unsuitable for SAVR, the cost-effectiveness of a broad policy of introducing TAVI may fall below £20,000 per QALY. Future work required includes the incorporation of new data made available after completion of this work.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Numerical method for the stochastic projected Gross-Pitaevskii equation

We present a method for solving the stochastic projected Gross-Pitaevskii equation (SPGPE) for a three-dimensional weakly interacting Bose gas in a harmonic-oscillator trapping potential. The SPGPE contains the challenge of both accurately evolving all modes in the low-energy classical region of the system, and evaluating terms from the number-conserving scattering reservoir process. We give an accurate and efficient procedure for evaluating the scattering terms using a Hermite-polynomial based spectral-Galerkin representation, which allows us to precisely implement the low-energy mode restriction. Stochastic integration is performed using the weak semi-implicit Euler method. We extensively characterize the accuracy of our method, finding a faster-than-expected rate of stochastic convergence. Physical consistency of the algorithm is demonstrated by considering thermalization of initially random states.

Characteristics of two-dimensional quantum turbulence in a compressible superfluid

Fluids subjected to suitable forcing will exhibit turbulence, with characteristics strongly affected by the fluid's physical properties and dimensionality. In this work, we explore two-dimensional (2D) quantum turbulence in an oblate Bose-Einstein condensate confined to an annular trapping potential. Experimentally, we find conditions for which small-scale stirring of the condensate generates disordered 2D vortex distributions that dissipatively evolve toward persistent currents, indicating energy transport from small to large length scales. Simulations of the experiment reveal spontaneous clustering of same-circulation vortices and an incompressible energy spectrum with k(-5/3) dependence for low wave numbers k. This work links experimentally observed vortex dynamics with signatures of 2D turbulence in a compressible superfluid.

In search of Pinkel's children: unravelling the biological heterogeneity of childhood acute lymphoblastic leukaemia by genotype and treatment molecular response

BACKGROUND

Acute lymphoblastic leukaemia (ALL), the commonest childhood malignancy has seen remarkable progress since the 1960s with cure rates now approaching 85%. To achieve this patients undergo intensive treatment that usually takes 2.5-3.5 years involving on average 15 different chemotherapeutic drugs. In 1971, Donald Pinkel reported Total Therapy-Protocol V that used 5 drugs and cranial radiation therapy over a similar time period. Today, one half of these patients (Pinkel's children) remain alive and free of leukaemia.

AIM

The aim of this study was to evaluate the impact post-induction minimal residual disease (MRD) levels had on survival and its relationship with the more established clinical and biological prognostic predictors of outcome in the hope of identifying a subgroup of patients that are at very low risk of failure.

METHODS

A retrospective review of 250 Irish children with ALL was carried out. MRD status after 28 days of induction chemotherapy and other known predictors of outcome were correlated with 5 year event-free survival (EFS).

RESULTS

MRD status was the strongest predictor of outcome with 5 year EFS rates greater that 90% seen in those patients with low-risk MRD and this was associated with TEL/AML1 rearrangement, high hyperdiploidy (HH) karyotype and female gender.

CONCLUSION

Both MRD and karyotype are powerful determinants of outcome in childhood ALL. Therefore, it is reasonable to conclude that the majority of children cured by Pinkel et al. in the late 1960s were most likely composed of low-risk MRD, TEL/AML1 and HH patients.

Comparison of three cuffed emergency percutaneous cricothyroidotomy devices to conventional surgical cricothyroidotomy in a porcine model

BACKGROUND

Emergency cricothyroidotomy is a potentially life-saving procedure in the 'cannot intubate cannot ventilate (CICV)' scenario. Although surgical cricothyroidotomy remains the technique recommended in many 'CICV' algorithms, the insertion of a tracheostomy as a cannula over a trocar, or using the Seldinger method, may have advantages as they are more familiar to the anaesthetist. We compared the utility of three cuffed cricothyroidotomy devices: cuffed Melker®, Quicktrach 2®, and PCK® devices, with surgical cricothyroidotomy.

METHODS

After ethical committee approval and written informed consent, 20 anaesthetists performed cricothyroidotomy with all four devices in random order, in a pig larynx and trachea model covered in cured pelt. The primary endpoints were the rate of successful placement of the cricothyroidotomy device into the trachea and the duration of the insertion attempt.

RESULTS

The Melker® and Quicktrach 2® devices possessed advantages over the surgical approach, in contrast to the PCK® device, which performed less well. All 20 participants inserted the Melker®, with 19 being successful using the surgical approach and the Quicktrach 2®, whereas only 12 successfully inserted the PCK® device (PCK® vs surgical, P=0.02). The Quicktrach 2® had the fastest insertion times and caused least trauma to the posterior tracheal wall. The Melker® was rated highest by the participants and was the only device rated higher than the surgical technique.

CONCLUSIONS

The Melker® and Quicktrach 2® devices appear to hold particular promise as alternatives to surgical cricothyroidotomy. Further studies, in more clinically relevant models, are required to confirm these initial positive findings.

Reactivity of P-Glycoprotein Monoclonal Antibodies in Childhood Cancers

P-Glycoprotein (P-gp), the product of the mdr-1 gene, is implicated in the development of chemoresistance in a variety of, mostly adult, cancers. Its role in paediatric tumours, most of which are non-epithelial in origin, has yet to be fully elucidated. A study was undertaken to investigate reactivity of two P-gp monoclonal antibodies (MAbs), JBS-1 and MRK16, recognising cytoplasmic and surface epitopes, respectively, of the P-gp molecule, in a variety of newly diagnosed and relapsed childhood cancers. P-gp was not expressed in any of 36 tumours examined (neuroblastoma 13, nephroblastoma 12, rhabdomyosarcoma 6, lymphoma 3, teratoma 1, Ewings 1), 14 of whom had chemoresistant disease. Reactivity to both MAbs was also investigated in patients with acute leukaemia. Out of 10 diagnostic acute lymphoblastic leukaemia (ALL) samples, a positive reaction with JSB-1 was observed in 1 patient who failed to remit on standard induction therapy and in 3 of 6 patients in ALL relapse, only 1 of whom showed low grade positivity with MRK16. Both MAbs reacted positively in 1 patient with acute non-lymphocytic leukaemia (ANLL) at diagnosis who achieved remission with teniposide and cytosine arabinoside, but relapsed 7 months later and was again positive with both Mabs. JSB-1 also showed varying degrees of positivity in 4 out of 4 other patients in ANLL relapse. It would therefore appear that P-gp is unlikely to mediate chemoresistance in most solid tumours of childhood, but may well play a major role in the development of chemoresistance in acute leukaemia.

Platelets in the paediatric population: the influence of age and the limitations of automation

Accurate and precise platelet counting is important for the clinical management of children with platelet disorders. Current automated technologies are often unable to discriminate platelets from non-platelet particles particularly in circumstances where platelet anisocytosis is common. This study compares manual methodology and the automated technologies; impedance, optical density and CD61 immunoplatelet method (available on the Cell Dyn 4000) with the reference method of flow cytometric analysis in a paediatric population. A total of 141 samples were analysed and divided into specific age related groups and groups with thrombocytopenia and thrombocytosis. Data analysis showed that the CD61 method compared best with the reference method and this was evident in all the specified groups. The mean platelet count obtained by optical and manual methods were lower, suggesting that these methods are less reliable. The impedance count method was accurate despite its limitations. Strong correlations were observed in the 2-14 year age group but there was greater variation in the <1 month group supporting the theory that there is a greater variation in platelet characteristics in neonates. The CD61 method is the automated method of choice and would be particularly useful in the problem groups (platelet counts <50 x 10(9)/l and neonates <1 month old).

Imaging the post-operative thoracic aorta: normal anatomy and pitfalls

Following surgical repair or replacement of the thoracic aorta, interpretation of CT and MRI scans of the thorax can be confusing. It is important to be aware of the variety of appearances that can be encountered. There is usually a surgical explanation and close collaboration with surgical colleagues is required. An appreciation of the normal post-operative appearances allows recognition of the abnormal. Potential pitfalls in interpretation are discussed.

Complement-mediated killing of Borrelia burgdorferi by nonimmune sera from sika deer

Various species of cervid deer are the preferred hosts for adult, black-legged ticks (Ixodes scapularis and Ixodes pacificus) in the United States. Although frequently exposed to the agent of Lyme disease (Borrelia burgdorferi), these animals, for the most part, are incompetent as transmission reservoirs. We examined the borreliacidal activity of normal and B. burgdorferi-immune sera from sika deer (Cervus nippon) maintained in a laboratory setting and compared it to that of similar sera from reservoir-competent mice and rabbits. All normal deer sera (NDS) tested killed > 90% of B. burgdorferi cells. In contrast, normal mouse and rabbit sera killed < or = 22% of the Borrelia. Anti-B. burgdorferi antibodies could not be detected in any normal sera by indirect fluorescent antibody assay (IFA). Sera collected from deer 6 wk after exposure to B. burgdorferi by tick feeding exhibited IFA titers of 1:256, whereas sera from mice and rabbits similarly exposed had titers of > 1:1,024. Heat treatment (56 C, 30 min) of NDS reduced borreliacidal activity, with < 20% of the B. burgdorferi cells killed, suggesting complement-mediated killing. The chelators EGTA and EDTA were used to block the classical or both the classical and alternative complement pathways, respectively. Addition of 10 mM EGTA to NDS had a negligible effect on borreliacidal activity, with > 90% of the cells killed. Addition of 10 mM EDTA reduced the killing to approximately 30%, whereas the addition of Mg2+ (10 mM) restored borreliacidal activity to NDS. The addition of zymosan A, an activator of the alternative pathway, increased the survival of B. burgdorferi cells to approximately 80% in NDS. These data suggest that the alternative complement activation pathway plays a major role in the borreliacidal activity of NDS. Additionally, 10 mM EGTA had almost no effect on the killing activity of B. burgdorferi-exposed deer sera, suggesting that the classical pathway is not involved in Borrelia killing, even in sera from B. burgdorferi-exposed deer.

Clinical and patho-anatomical factors affecting expansion of thoracic aortic aneurysms

OBJECTIVE

To examine the expansion of aneurysmal aortic segments (> or = 35 mm) and to assess the impact of clinical and patho-anatomical factors on aneurysm expansion.

DESIGN

87 consecutive patients (mean age 63.6 years, range 22-84 years) were studied using serial (six month intervals) computed tomographic or magnetic resonance imaging to monitor progression of thoracic aortic aneurysms. Aortic diameter was measured at seven predetermined segments and at the site of maximum aortic dilatation (MAX).

RESULTS

780 segment intervals were identified. The median overall aneurysm expansion rate was 1.43 mm/year. This increased exponentially with incremental aortic diameter (p < 0.01) and varied by anatomical segment (p < 0.05). The presence of intraluminal thrombus (p < 0.01) but not dissection or calcification was associated with accelerated growth. Univariate analysis identified thrombus (p < 0.001), previous stroke (p < 0.002), smoking (p < 0. 01), and peripheral vascular disease (p < 0.05) as factors associated with accelerated growth in MAX. Dissection, wall calcification, and history of hypertension did not affect expansion. beta Blocker treatment was not associated with protection. Multivariate analysis confirmed the positive effect of intraluminal thrombus and previous cerebral ischaemia, and the negative effect of previous aortic surgery on aneurysm growth. These findings translated into a mathematical equation describing exponential aneurysm expansion.

CONCLUSIONS

Aneurysmal thoracic aortic segments expand exponentially according to their initial size and their anatomical position within the aorta. The presence of intraluminal thrombus, atherosclerosis, and smoking history is associated with accelerated growth and may identify a high risk patient group for close surveillance.

Reduction of endothelial injury after hypothermic lung preservation by initial leukocyte-depleted reperfusion

OBJECTIVES

Leukocyte depletion has been shown to ameliorate the effects of reperfusion injury in many organ systems. The aim of this study was to investigate the effects of leukocyte depletion on functional and endothelial markers of pulmonary performance after cold ischemic injury.

METHOD

Groups of 6 rat lungs were flushed with University of Wisconsin solution and then stored at 4 degrees C for 4 hours. They then underwent sanguine reperfusion for 30 minutes, during which time functional measures (gas exchange, pulmonary artery, and airway pressures) were made and after which the lungs underwent estimation of endothelial permeability by measurement of the capillary filtration coefficient (in grams per centimeter of water per minute per grams of wet lung tissue) by a gravimetric technique. Four groups were studied: group 1 underwent no reperfusion, group 2 underwent 30 minutes of reperfusion, group 3 underwent 30 minutes of leukocyte-deplete reperfusion with an in-line leukocyte filter (PALL), and group 4 underwent 10 minutes of leukocyte-depleting reperfusion followed by 20 minutes of normal reperfusion.

RESULTS

The capillary filtration coefficient increased between group 1 and group 2 animals (1.05 +/- 0.32 to 3.07 +/- 0.47 [mean +/- SEM]; P <.01). Complete leukocyte depletion caused the greatest diminution in the capillary filtration coefficient (0.392 +/- 0.07, P <.001), but initial leukocyte depletion (group 4) also showed a significant diminution (0.74 +/- 0.3, P <.01). Complete or initial leukocyte depletion caused no significant change in functional measures of pulmonary performance. Complete leukocyte depletion produced less pulmonary leukostasis, as assessed by means of myeloperoxidase activity.

CONCLUSION

Initial and continued leukocyte depletion are associated with amelioration of reperfusion-induced endothelial injury after cold ischemic injury.

Differential time scale of fluid and solute permeability following hypothermic lung preservation

BACKGROUND

Assessment of the quality of lung graft preservation by simple functional measures in some laboratory models may fail to detect endothelial injury. The effects of hypothermic preservation in isolation were investigated by measuring the pulmonary capillary filtration coefficient (Kf) and the albumin surface area product (PS) at various cold ischemic intervals.

METHODS

Rat lungs were flushed with University of Wisconsin solution at 4 degrees C. Following storage at 4 degrees C, lungs for Kf measurement were subjected to a change in pulmonary arterial pressure. Kf was calculated from the change in rate of weight gain as a function of hydrostatic stress. PS lungs were exposed to Tris buffered Ringer's solution containing 1125 albumin (20 microM) in an isogravimetric state. Following a vascular flush the lungs were homogenized and underwent scintillation counting. Using the Kedem-Katchalsky equation PS was calculated.

RESULTS

The Kf for the control, 4-hour, and 7-hour groups were 0.778, 1.816, 4.853 g/ cm H2O/min/100 g wet lung tissue, respectively. There was a significant increase in Kf with each time increment (P,0.01). The Kf for the 24-hour group was 5.587 g/cm H2O/min/100 g wet lung tissue; not an additional significant increase. PS for the control and 4-hour groups (0.0115 and 0.0101 cm3/g wet lung tissue/minute, respectively) were not significantly different. After 7 hours there was a significant increase to 0.171 cm3/g wet lung tissue/min. PS could not be measured after 24 hours.

CONCLUSIONS

Significant endothelial injury occurs after 4 hours of cold ischemic preservation. There is progressive injury with time. Increase in water permeability is not secondary to increase in albumin permeability.

Replacement of the proximal aorta and aortic valve using a composite bileaflet prosthesis and gelatin-impregnated polyester graft (Carbo-Seal): early results in 143 patients

OBJECTIVE

We report the combined early results from two centers in the United Kingdom using a composite conduit consisting of a bileaflet mechanical valve incorporated into a gelatin-impregnated, ultra-low porosity, woven polyester graft (Carbo-Seal; Sulzer Carbomedics, Inc, Austin, Tex).

METHODS

Between August 1992 and March 1997, 143 patients underwent aortic root replacement with the Carbo-Seal composite prosthesis. The indication for surgery was acute type A dissection in 31 (22%), chronic type A dissection in 9 (6%), ascending aortic aneurysm without dissection in 100 (70%), and false aneurysm of the ascending aorta in 3 (2%). Twenty-seven patients (19%) had undergone previous sternotomy, and 40 (28%) were seen as emergencies. Concomitant procedures were performed in 38 (27%), including 18 aortic arch or hemiarch replacements. Total follow-up is 270 patient-years. Follow-up is 100% complete.

RESULTS

The early (30-day) mortality was 7% (10 patients). Permanent neurologic events occurred in 2%. At a mean follow-up of 23 months, 94% of survivors were in New York Heart Association functional class I. Freedom from reoperation was 97.2% +/- 1.6% (1 standard error [1 SE]) at 12 months and 95.7% +/- 2.2% at 48 months. Including early mortality, survival was 90.1% +/- 2.6% at 12 months and 83.1% +/- 3. 5% at 48 months.

CONCLUSIONS

Aortic root replacement with use of the Carbo-Seal prosthesis can be undertaken with a relatively low early mortality and morbidity. A low reoperation rate and high intermediate-term survival can be expected, but continued follow-up is needed to determine the long-term efficacy of this prosthesis.

Irish students and medical education

The attitudes of a final year of medical students in University College Dublin and their level of satisfaction to their medical training was assessed. Medical students were significantly more dissatisfied with their pre-clinical teaching than clinical teaching and training. The majority of students felt inadequately trained in dealing with specific issues relating to patient care and communication. The most popular suggestions for improving the undergraduate teaching programme included increasing the use of patient case vignettes, small group tutorials and presenting patients' cases.

Reproducibility of thoracic aortic diameter measurement using computed tomographic scans

OBJECTIVES

Decisions to recommend elective surgical repair of thoracic aortic aneurysms (TAA) may be based on size or expansion rate, which are used as indices of the risk of rupture. Measurement error may thus affect clinical decision-making. In order to evaluate the reproducibility of aortic diameter measurements of TAA, we assessed departmental inter- and intra-observer variability of measurement of pre-selected computed tomographic scan images of aneurysmal segments of the thoracic aorta.

METHODS

We compared measurements of minimum aortic diameter made by four observers in 50 pre-selected scans and at different times by two observers using a calliper method and a measurement tool within the scan. Differences in measured dimension were analysed using Wilcoxon's signed ranks test and the repeatability assessed using the method of Bland and Altman.

RESULTS

There were no significant inter-observer differences among three observers but there were significant differences between another observer and two other observers (P < 0.05). No significant intra-observer differences existed. The best intra-observer repeatability was 2.25 while the worst inter-observer repeatability was 4.37. The mean and maximum difference in measurement were +/-0.88 mm and +/-8.0 mm, respectively. Variability of measurement increased with aortic diameter.

CONCLUSIONS

Calliper measurement of TAA is an acceptable measurement method for surveillance of TAA but appears most accurate with a single observer. Increasing error is seen with increasing diameter which may compound error in estimation of expansion rate. Standardisation of technique is advisable for multiple observers and aortic units should adopt quality assurance protocols to minimise error.

Prediction of thoracic aortic aneurysm expansion: validation of formulae describing growth

BACKGROUND

The expansion rate of thoracic aortic aneurysms may be an important and clinically relevant index of the risk of rupture. The aims of this study were to assess the validity of three published exponential equations that predict expansion rate in a separate sample population, and to calculate an expansion rate formula for this cohort of patients.

METHODS

We studied 88 consecutive patients undergoing serial computed tomographic or magnetic resonance imaging scanning to monitor thoracic aortic aneurysm progression. In interval scans of at least 6 months, we measured minimum coronal aortic diameter at seven set levels and maximal diameter, yielding 780 segment-intervals.

RESULTS

The linear expansion rate (mean 2.6 mm/year) increased with incremental aortic diameter (aortic diameter < 40 mm: 2.0; 40-49 mm: 2.3; 50-59 mm: 3.6; > or = 60 mm: 5.6 mm/year; p < 0.01). Regression analysis showed close correlation between predicted and sample data, but there were significant differences between observed and expected measurements. The Yale formula underestimated growth by 0.8 mm, while Mt. Sinai and Osaka formulae overestimated actual change by 1.5 and 0.2 mm, respectively. The expansion rate derived from our population was: last diameter = initial diameter x e(0.00367 x time) (r = 0.617).

CONCLUSIONS

Although formulae derived from one thoracic aortic aneurysm sample population may not extrapolate exactly to others, there is close concordance of results for patient populations in three different continents.

S-100beta release in hypothermic circulatory arrest and coronary artery surgery

BACKGROUND

Aortic surgery utilizing profound hypothermic circulatory arrest (HCA) has a higher incidence of neurological injury than coronary artery bypass grafting (CABG). S-100beta is a potential marker of cerebral ischemic injury. The aim of this study is to assess its use in investigating cerebral injury during HCA.

METHODS

We studied 40 patients (10 CABG, 30 HCA). The mean cardiopulmonary bypass (CPB) times were 72 and 158 minutes, respectively. Mean HCA duration was 27.6 min, with retrograde cerebral perfusion (RCP) used in 18 patients (mean 28.5 minutes, 95% CI 16-25). Perioperative venous blood samples were subjected to S100beta assay.

RESULTS

S100beta levels with HCA (peak: 2.68 microg/L, 95% CI 1.99-3.38 microg/L; calculated area under the curve [AUC]: 1596 microg/L/min, 95% CI 825-2368 microg/L/min) were significantly higher (peak, p = 0.028 and AUC, p = 0.007) than with CABG (peak: 1.16 microg/L, 95% CI 0.25-2.1 microg/L and AUC: 53.4 microg/L/min 95% CI 3.0-103.8). Peak S100beta correlated with CPB time in CABG cases (r = 0.76, p < 0.05), and with both CPB and HCA time in HCA cases: without RCP (r = 0.46 and 0.21, respectively, p > 0.05) and with RCP (r = 0.88 and 0.33, respectively, p < 0.05). There was no significant difference in the S100beta levels between HCA groups with and without RCP, but HCA time was longer in the RCP group (p = 0.05).

CONCLUSIONS

S100beta release correlates with duration of CPB and HCA. Elevated serum S100 indicates astrocyte death or activation, and suggests blood-brain barrier dysfunction. The continuing release of S100 after the end of operation suggests that HCA may be associated with greater injury than CABG. RCP did not influence S-100beta release in this study.

Co-abuse of opiates and benzodiazepines

The objective of the study was to assess what differences exist between individuals who are dependent on opiates and benzodiazepines and compare to those who are dependent on opiates. A questionnaire was compiled and administered to patients who had been consecutively admitted to an inpatient drug treatment unit. The prevalence of benzodiazepine dependency was 54 per cent [n = 34]. Patients dependent on benzodiazepines and opiates were significantly older, had been admitted for methadone stabilisation and were more likely to have been prescribed a methadone maintenance programme prior to admission. They had used heroin longer, benzodiazepines more frequently, at larger doses for a longer duration of time and tended to use more drugs in general. They were found to be more psychologically vulnerable than those not dependent on benzodiazepines as they were significantly more likely to have described a past experience of depression and a past episode of deliberate self harm.

Prevalence of abnormal thyroid function tests in a Down's syndrome population

As thyroid function has been documented to be of a higher prevalence in individuals with Down's syndrome, a study was set up to assess the thyroid status of these individuals. Thyroid function tests (T.F.T.s) were initially reviewed on 100 individuals with Down's syndrome in the community and on 36 individuals who were residentially based. Abnormal T.F.T.s were then reviewed 3 yr later. In total sample of 136, initially 13 percent [n = 18] of individuals with Down's syndrome had abnormal T.F.T.s, 5 percent [n = 7] were established cases of thyroid disease and 8 percent [n = 11] were newly identified cases who had abnormal T.F.T.s. Three yr later 6.5 percent [n = 9] of the group who had had abnormal T.F.T.s continued to have abnormal T.F.T.s, 5 percent [n = 7] had thyroid disease and 1.5 percent [n = 2] still had biochemical evidence of thyroid dysfunction. There was a statistically significant increase in abnormal T.F.T.s in the residential sample compared to the community sample on both occasions. The incidence of thyroid dysfunction has been found to increase with age, particularly over the age of 40, however in this study the majority were under the age of 40 with an age range between 28.3 yr and 33.8 yr. The results in this study, coupled with the variability of T.F.T.s over time, highlights the need for regular monitoring of the thyroid status of individuals with Down's syndrome.

Connection closures adding application-defined behaviour to network connections

New techniques in the implementation of out-of-band control in ATM networks are causing both industry and research laboratories to look again at the whole question of ATM signalling. These techniques devolve the control from the network devices into a higher level distributed processing environment, resulting in simpler network devices and more flexible control architectures.This paper takes this idea one stage further and suggests that at least in some cases, the only place in which control can be exerted without inhibiting applications is within the applications themselves. We call the combination of an application defined control policy and a network connection a connection closure .

The management of bleeding following surgery requiring hypothermic circulatory arrest

BACKGROUND

Hemostasis is a significant problem in aortic surgery requiring profoundly hypothermic techniques. Aprotinin, a serine protease inhibitor, reduces blood loss in high-risk coronary and valve surgery, but its use in profound hypothermia is controversial.

METHODS

To evaluate the role of a modified protocol of aprotinin administration we have retrospectively reviewed our results in 73 procedures when hypothermic circulatory arrest was necessary. Thirty-seven (51%) were emergencies. Aprotinin was not administered until bypass had been recommenced after the period of circulatory arrest, and was then given as a bolus of 280 mg into the bypass machine followed by an intravenous infusion of 70 mg/hour.

RESULTS

In this series the 30-day mortality was 12.3% (9/73), and the in-hospital mortality 13.7% (10/73). Mortality in the elective group was 11.1% and 16.2% in the emergency group. The mean blood loss over the first 12 hours after surgery was 542 mL; the mean transfusion requirement during surgery and this 12 hour period was 3.6 units of blood. Six patients (8.2%) developed transient renal dysfunction which did not require intervention.

CONCLUSIONS

This data does not support the adverse effect of aprotinin upon early survival. Although early reports were of concern, the role of aprotinin as an adjunct to hemostasis requires further investigation.

Aprotinin in aortic surgery requiring profound hypothermia and circulatory arrest

OBJECTIVE

The use of aprotinin in cardiac surgery to improve haemostasis and reduce blood loss particularly in patient groups at increased risk of bleeding is well established. Previous retrospective studies in profound hypothermic surgery have highlighted concerns that in this circumstances aprotinin may paradoxically cause increased bleeding and intravascular thrombosis. We therefore adopted a modified protocol for administering aprotinin, which was not started until cardiopulmonary bypass had been reinstituted after circulatory arrest.

METHODS

Between April 1993 and June 1995, 45 patients underwent 46 thoracic aortic procedures which required hypothermic circulatory arrest; 25 of these were emergencies. All of these patients received aprotinin.

RESULTS

There were five deaths (10.8%) in hospital. Two patients with preoperative oliguric renal failure required postoperative dialysis, and a further six (13%) developed transient renal dysfunction with complete recovery. Two patients suffered postoperative stroke; one from embolisation of a severely diseased aorta, while the other had signs of an acute evolving stroke before surgery. None of the patients suffered acute Q-wave perioperative myocardial infarction. The mean blood loss was 575 ml in the first 12 h, with a mean postoperative transfusion requirement of 1 U blood.

CONCLUSIONS

We cannot implicate aprotinin in increased postoperative blood loss, renal dysfunction or mortality when used with hypothermic circulatory arrest according to this protocol. Elucidating the role of aprotinin in hypothermic circulatory arrest requires a randomised prospective study.

Analysis of the RET proto-oncogene in sporadic parathyroid adenomas

Missense germline mutations of the RET proto-oncogene have recently been identified in the hereditary cancer syndromes MEN2A, MEN2B, and FMTC, all characterized by medullary carcinoma, but also including phaeochromocytoma in MEN2A and MEN2B and parathyroid disease in MEN2A. In addition, somatic RET proto-oncogene mutations have been identified in a subset of sporadic medullary carcinomas and phaeochromocytomas. This study investigated the possibility that RET plays a role in sporadic parathyroid neoplasia. Firstly, normal and neoplastic parathyroid tissues were screened for expression of the RET proto-oncogene, using an RT-PCR approach on autopsy material. Secondly, 20 archival parathyroid adenomas were screened for somatic mutations in the transmembrane region of RET, the region associated with germline mutations in MEN2A and hence parathyroid disease, using a PCR-solid phase direct sequencing approach. RET expression was identified in all the parathyroid tissues analysed. However, no mutations were identified in any of the 20 adenomas, suggesting either that other mechanisms of RET activation occur, such as translocation, or that RET plays a more minor role in the growth control of the parathyroid cells than in C cells or phaeochromocytes.

RET activation in adult and childhood papillary thyroid carcinoma using a reverse transcriptase-n-polymerase chain reaction approach on archival-nested material

Activation of the RET tyrosine kinase domain occurs in a proportion of thyroid papillary carcinomas. Three chromosomal rearrangements have been described, of which PTC1 is the commonest. Wide differences (2.5-25%) in frequency of PTC1 in different populations have been reported; it is not clear whether these are due to environmental factors, racial differences or technical reasons. We have developed a simple and rapid reverse transcriptase nested polymerase chain reaction (RT-nPCR) method enabling the detection of gene expression from single 5 microns sections of formalin-fixed paraffin wax-embedded archival material. We have applied this approach to detect expression of the RET tyrosine kinase domain, allowing identification of RET activation resulting from any rearrangement, whether characterised or not, or from overexpression. A retrospective study was performed on 22 adult and 21 childhood papillary carcinomas. Thirteen of 22 (59%) adult and 10 of 21 (48%) childhood carcinomas showed evidence of RET activation, demonstrating a major role for the RET oncogene in UK thyroid papillary carcinogenesis. This study also shows a similar frequency of RET activation in both children and adults. The use of a technique that allows reliable amplification of RNA from archival material, using primers chosen in different exons so that amplified products are readily distinguished from genomic DNA, will allow correlation of translocations and chromosomal rearrangements with a variety of specific tumour types.

Suture loop restriction of the medtronic hall valve: late presentation of a rare complication

Restriction of movement of the occluder of a single disc prosthetic valve is a serious and potentially fatal complication. We present a case in which the movement of the disc of a Medtronic Hall aortic valve was restricted by a loop of aortotomy closing suture inadvertently passed around the central guide of the valve.

Arterial risk factors and ischemic cerebrovascular events after aortic valve replacement

To assess the association of possible risk factors with ischemic cerebrovascular events after aortic valve replacement (AVR), 619 consecutive patients undergoing AVR with a Medtronic Hall valve between the beginning of December 1979 and the end of December 1992 and surviving the immediate postoperative period were analyzed. Possible risk factors examined were valve lesion, prosthesis size, postoperative functional status, systemic hypertension, cigarette smoking, diabetes, coronary artery disease and atrial fibrillation. There were 53 ischemic cerebrovascular events in 38 patients during 3,174 follow up years, yielding a linearized event rate of 1.7%/patient-year. Significant risk factors in terms of odds ratios (OR) were postoperative hypertension (OR 8.0), postoperative NYHA class III or IV (OR 5.5), postoperative smoking (OR 4.0), diabetes (OR 3.5), preoperative hypertension (OR 2.7) and preoperative smoking (OR 1.8). There was highly significant interaction between postoperative hypertension and postoperative smoking (OR 54.0). Eighty-one percent of patients who suffered events were hypertensive or smoking postoperatively or both. These findings have important implications for postoperative management and for the reporting of ischemic cerebrovascular events after valve replacement.

The role of risk factors and trigger factors in cerebrovascular events after mitral valve replacement: implications for antithrombotic management

To determine the effect of risk factors and trigger factors on cerebrovascular events, 622 patients who survived mitral valve replacement between December 1979 and December 1992 were analyzed. Ninety-six patients suffered 139 nonhemorrhagic cerebrovascular events. Data were available on 138 events in 95 patients. There were 32 transient ischemic attacks (TIAs), 57 reversible ischemic neurological deficits (RINDs), and 49 strokes. Age, sex, atrial fibrillation, left atrial size, systemic hypertension, and abnormal body mass index did not discriminate between patients who suffered events and those who did not. In contrast, smoking status differed significantly between patients who suffered events and those who did not. Among current or recent ex-smokers, the risk of stroke or RIND was significantly higher than in non-smokers (p < < 0.001). The odds ratio of suffering any type of event in patients who smoked at any time postoperatively versus those who did not smoke was 2.9 (95% confidence interval: 1.8 to 4.6). Of 61 patients contacted directly, 30% recalled an infective episode immediately prior to their event. A diurnal and seasonal influence on events was also detected with peaks in the morning and in the winter months, respectively (both p < 0.001). It is concluded that there is persuasive evidence for the involvement of several nonprosthetic factors in the incidence of cerebrovascular events after mitral valve replacement. This has implications for patient management and for future analysis of prosthetic heart valve series.

Sudden death in a large prosthetic valve series based on a single prosthesis: experience with the medtronic Hall valve

In order to test the validity of the current guidelines on the categorization of non-autopsied sudden death after valve replacement, a detailed analysis was undertaken of 412 deaths in a large single-institution prosthetic series based on one type of prosthesis (Medtronic Hall) over a 13-year period. Of 69 sudden or unwitnessed deaths, 48 (70%) were autopsied. There were no sudden deaths specifically related to the prosthesis itself, 79% of deaths were due to coronary disease or left ventricular dysfunction and 10% were due to intracranial hemorrhage. Overall, 90% of sudden deaths were unrelated to the prosthesis A seasonal fluctuation in the incidence of sudden and unwitnessed deaths was demonstrated in keeping with the known epidemiology of sudden death in the general population. It was concluded that there was no evidence to support the recommendation that all non-autopsied sudden deaths should be attributed to the prosthesis.

Mucolytic activity of azelastine in mice and rats

The mucolytic activity of azelastine, an antiallergic/antiasthmatic drug, in mice and rats was investigated. The oral administration of test compounds 30 min before phenol red i.p. injection stimulated dye secretion in the trachea of mice. The resulting oral ED50's (mg/kg) were: azelastine, 0.16; salbutamol, 2.5; N-acetylcysteine, 61.8; S-Carboxymethyl-l-cysteine, < 100; bromhexine, > 100; and potassium iodide, approximately 200. In rats, several drugs stimulated secretion of fluorescein sodium (FINa) in the tracheobronchial lumen. The resulting oral ED50's (mg/kg) were: azelastine, 0.33; terbutaline, 0.3; salbutamol, 0.89; and S-carboxymethyl-l-cysteine, 56.8. Terfenadine and diphenhydramine (1-10 mg/kg, p.o.) did not stimulate tracheal secretion in rats and mice. The mucolytic activity of azelastine may contribute to its overall effectiveness, including antitussive activity in asthmatics. Finally, this activity seems to be dissociated from its H1-histamine receptor blocking activity.

Anti-IL-5 monoclonal antibody inhibits allergic late phase bronchial eosinophilia in guinea pigs: a therapeutic approach

In this study the effect of purified rat anti-mouse IL-5 monoclonal antibody on aeroallergen-induced infiltration of eosinophils in the bronchoalveolar lavage fluid of guinea pigs was studied. The i.p. injection of anti-IL-5 antibody 4 h after aeroallergen challenge inhibited eosinophil infiltration in a dose-dependent fashion. The resulting ED50 was 10 (3.4-32.8) micrograms/kg. The clinical therapeutic usefulness of anti-IL-5 or anti-IL-5-producing cells in asthma/allergy treatment remains to be an intriguing possibility.

A randomized comparison of infrared photocoagulation with bipolar diathermy for the outpatient treatment of hemorrhoids

One hundred two patients with symptomatic hemorrhoids were randomized to receive treatment with either infrared photocoagulation (IRPC) or a bipolar diathermy probe (BD). There was no significant difference in complications, number of treatments required (IRPC 1.7 [0.9], BD 1.6 [0.8]). Third-degree hemorrhoids required more treatments than smaller piles. BD has some practical advantages over IRPC but results are similar.