Catheter ablation vs medical therapy for treatment of atrial fibrillation patients with heart failure with preserved ejection fraction: a systematic review and meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Introduction

Catheter ablation (CA) is used as a treatment option in selected patients with atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF) as studies have shown that it reduces heart failure (HF) hospitalization, improves survival, and reduces rates of AF recurrence when compared to medical therapy. However, it is not known whether this benefit persists in patients with heart failure with preserved ejection fraction (HFpEF).

Purpose

The aim of this meta-analysis is to compare CA versus medical therapy in patients with AF and HFpEF

Methods

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were searched from August 2012 to August 2022. All randomized controlled trials (RCTs), propensity score matched (PSM) studies, and observational studies including conference abstracts providing outcomes in patients with HFpEF and AF after CA were included. Outcomes examined include all-cause mortality, HF hospitalizations, and AF recurrence. A random-effects model using R statistical software was used to calculate odds ratios (OR) and 95% confidence intervals (CI).

Results

Of 3151 studies screened, 8 studies (1 RCT, 4 PSM, 3 observational) were included with a pooled population of 2171 and 24087 patients with AF and HFpEF who underwent CA and medical therapy respectively. There were no significant differences in baseline age (70.6 vs 70.7, p = 0.16), proportion of hypertension (85.0% vs 86.4%, p = 0.58), diabetes (33.8% vs 35.8%, p = 0.39), coronary artery disease (40.2% vs 41.8%, p = 0.06), or men (42.3 vs 36.6%, p = 0.42). After a mean weighted follow-up of 9.45 months, there was no significant difference in all-cause mortality (OR 0.77 [0.47-1.26], p = 0.07), HF hospitalizations (OR 0.44 [0.18-1.08], p = 0.22), but a significantly lower rate of AF recurrence (OR 0.22 [0.09-0.54], p = 0.001) associated with CA.

Conclusion

In patient with HFpEF, CA significantly reduced AF recurrence compared with medical therapy but with no difference in mortality or HF hospitalization. CA continues to have an important role to play in treatment of AF even in HFpEF patients.

Ablation therapies for paroxysmal atrial fibrillation: a systematic review and patient-level network meta-analysis

Background

Despite numerous promising trials, catheter ablation is still regarded as a second-line alternative to antiarrhythmic drugs (AAD) in the treatment of paroxysmal atrial fibrillation (PAF). There remains a role for a broad comparison of the effectiveness of various ablation therapies against each other, and versus AAD.

Purpose

To conduct a systematic review and network meta-analysis of ablation therapies and AAD in the treatment of PAF. Ablation therapies were hypothesized to be superior to AAD in preventing atrial fibrillation (AF) recurrence.

Methods

An electronic literature search was conducted to retrieve randomized controlled trials or propensity score-matched studies comparing freedom from AF recurrence among any combination of ablation modalities or AAD. Kaplan-Meier curves and risk tables for this outcome were graphically reconstructed to extract individual patient data (IPD). A Frequentist network meta-analysis (NMA) was performed using the derived hazard ratios (HRs) of each study to compare various ablation therapies and AAD. Two separate NMAs were also conducted with restricted mean survival time (RMST) analysis, using RMST absolute differences and ratios, in light of violation of the proportional-hazards assumption. Treatment strategies were ranked using P-scores. Pairwise comparisons were also performed between treatment pairs with three or more studies reporting direct comparisons.

Results

Across 24 studies comparing six ablation therapies, comprising 5274 patients, Frequentist NMA-derived HRs of AF recurrence compared to AAD were 0.35 (95% CI: 0.26–0.48) for cryoballoon ablation (CBA), 0.33 (95% CI: 0.25–0.45) for radiofrequency ablation (RFA), 0.21 (95% CI: 0.09–0.49) for combined CBA and RFA, 0.20 (95% CI: 0.11–0.39) for hot-balloon ablation (HBA), 0.44 (95% CI: 0.16–1.22) for laser-balloon ablation, and 0.33 (95% CI: 0.19–0.56) for pulmonary vein ablation catheter. RMST-based NMAs similarly showed a significant benefit of all ablation therapies over AAD in preventing AF recurrence. Although none of the HRs between pairs of ablation modalities were significant, P-scores for HBA and combined CBA and RFA were consistently higher than those of other treatments. Independent pairwise comparisons of RFA and CBA versus AAD were greatly in favor of ablation (shared-frailty HR=0.24, 95% CI: 0.19–0.31, p<0.001; shared-frailty HR=0.44, 95% CI: 0.35–0.56, p<0.001, respectively).

Conclusions

To our knowledge, this is the first network meta-analysis comparing a wide range of ablation therapies to AAD, synthesizing IPD from high-quality studies in three separate NMA models. The advantage of ablation therapies over AAD in preventing AF recurrence was consistently found across all three models. This strongly suggests that ablation should replace AAD as the first-line treatment for PAF in patients who are fit for the procedure. Moreover, the promising results of HBA underscore the need for more high-quality trials to be conducted.

Funding Acknowledgement

Type of funding sources: None.

Robotic distal pancreatectomy, a novel standard of care? First benchmark values for surgical outcomes from 14 international expert centers

Objective

Robotic distal pancreatectomy (DP) is emerging as the preferred treatment for body and tail tumors of the pancreas. To enable conclusive comparisons with the standard open or laparoscopic approaches and robotic surgery among centers, novel benchmark outcome values are urgently needed. Therefore, the aim of this study was to identify benchmark values from expert centers beyond the learning curve.

Methods

This multicenter study analyzed outcomes from consecutive patients undergoing robotic DP for resectable malignant or benign lesions from 14 international expert centers. After the learning curve, defined as the first 10 cases of robotic DP, all consecutive patients were included from the start of the program up to June 2020 with a minimum follow-up of 1 year. Benchmark patients were those without significant comorbidities including obesity (BMI >35 kg/m2) cardiac disease, chronic pulmonary disease.

Benchmark cutoff values were derived from the 75th or the 25th percentile of the median values of all benchmark centers.

Results

After reaching the learning curve, 289 (47%) of a total of 614 consecutive patients qualified as benchmark cases. The proportion of benchmark patients varied between 24%-64% per center. Benchmark cut-offs showed a low 6 month- postoperative mortality (<0.6%), but high overall morbidity (<58.3%). Benchmark cutoffs for operative time (<300 min), conversion rate (<3%), clinically relevant pancreatic fistulas (<26.9%), CCI at 90-days (<14.8), hospital stay (<7 days) and readmission rate (<22.9%). Benchmark cut-offs for complications remained unchanged after 3 months follow-up. For ductal adenocarcinoma benchmark cutoffs for number of lymph nodes were > 19 with an R0 resection rate of > 85%, and an overall survival of >86% and >52% after 1- and 5-years, respectively. Centers with a low cohort of benchmark patients (more difficult cases) had less clinically relevant pancreatic fistula (9% vs. 23%) and less overall complications (32% vs. 48%).

Conclusion

This benchmark analysis sets novel reference values for robotic DP, indicating favorable outcomes as compared to laparoscopic and open DP. These references values may serve for quality control of surgery in centers embarking in robotic DP, and include the procedure in the standard of care.

A74 SURVEILLANCE IMAGING FOLLOWING COMPLETELY RESECTED GASTROENTEROPANCREATIC NEUROENDOCRINE TUMORS: A SINGLE CENTER AUDIT OF LOCAL PRACTICE PATTERNS

Background

Neuroendocrine tumours (NET) are a heterogenous group of neoplasms that secrete peptides and neuroamines. For patients with potentially malignant gastroenteropancreatic (GEP) NET, surgical resection represents the only curative option. GEP NETs are characterized by long periods of disease-free survival and time-to-recurrence following surgical resection. Clinical guidelines recommend surveillance with cross sectional imaging, either CT or MRI, for at least 10 years.

Aims

The purpose of this study was to characterize local practice patterns of imaging surveillance (modality, frequency, and duration of follow-up) and how this compares to guideline recommendations.

Methods

We retrospectively reviewed clinical and imaging records from patients diagnosed with well-differentiated GEP NET at our center from January 2005 to July 2020 inclusive. Eligible cases were identified by a data analyst from the Alberta Cancer Board with each case being manually screened for eligibility. Exclusion criteria included patients with metastatic disease at presentation, G1 appendiceal NET < 1 cm, R0 G1 T1 rectal NET, and insulinoma. Location of primary NET, modality of surveillance imaging, date of test and duration of follow-up collected. The mean number of surveillance scans per person and per person-year follow-up based on the location of the primary NET were calculated.

Results

A total of 387 cases were initially retrieved with 62 eligible cases identified. The mean length of follow-up was 71 months (range 8 to 147). The mean number of surveillance scans was 7 (range 2 to 14) and the mean number of surveillance scans per person year was 1.1. Frequency of surveillance scans per year of follow-up did not differ based on the location of the primary tumor (p=0.966). Imaging modalities included cross sectional imaging (MRI and contrast enhanced CT) and nuclear medicine imaging (octreotide, MIBG, F-18 FDG-PET, and Gallium-68 DOTATATE PET CT). Most commonly, cross-sectional imaging was performed with CT or MRI representing 38% (n=166) and 39% (n=170) of all surveillance respectively. Nuclear medicine imaging was used in 15% (n=61) of surveillance scans and 3% used combined cross-sectional and nuclear medicine. Amongst cases with resection date >10 years (n=8) mean length of follow-up was 119 months (9.9 years).

Conclusions

Frequency and modality of imaging at our center is generally in accordance with current clinical guidelines, though the role of nuclear medicine imaging in this setting has not been established. CT and MRI were utilized equally during surveillance. The burden of these modalities in terms of radiation exposure and cost warrants further evaluation.

Funding Agencies

None

Acute procedural outcomes of his bundle pacing with or without electrophysiology mapping system: a multicenter study

Funding Acknowledgements

Type of funding sources: None.

Introduction

His bundle pacing (HBP) is associated with improved clinical outcomes compared to right ventricular apical pacing. However, it can be technically challenging and may result in prolonged fluoroscopy and procedural time.

Purpose

We sought to compare the feasibility of performing HBP with or without electrophysiology mapping (EP) system, focusing on evaluating acute procedural success, complication rates and short-term outcomes.

Methods

HBP patients at 3 hospitals were recruited between August 2018 to December 2020. HBP was performed with EP mapping system in 1 center, and without EP mapping in the other 2 centers. Acute procedural success was defined as either selective or non-selective His bundle capture with a threshold of less than or equal to 1.5V at 1ms at the end of procedure implantation.

Results

A total of 233 patients were recruited, of which HBP was performed with EP mapping in 77 patients (33.0%) and without EP mapping in 156 patients (67.0%). Both groups were similar in age (73.2 ± 11.0 years vs 75.3 ± 9.5 years, p = 0.125) and male sex (58.4% vs 48.1%, p = 0.136). There were more patients with ischemic heart disease (45.5% vs 22.4%, p < 0.01) and reduced left ventricular ejection fraction ≤ 40% (28.6% vs 10.9%, p < 0.01) in the group with EP mapping. The indications for HBP was for high-grade atrioventricular block (55.8%), sick sinus syndrome (35.6%) and cardiac resynchronization therapy (CRT) (8.6%). There were more patients who required CRT in the center with EP mapping (18.2% vs 3.8%, p < 0.01). HBP was successful in 39 patients (50.6%) with EP mapping and 93 patients (59.6%) without EP mapping (p= 0.382). The median R wave at implant was similar in both groups [4.0 (2.9 – 6.2) mV vs 4.3 (4.3 – 7.0) mV, p = 0.808]. Impedance at implant (607 ± 195 ohms vs 547 ± 166 ohms, p < 0.01) and selective His bundle bipolar threshold at implant [1.25 (0.75-1.75) V vs 0.7 (0.5 – 1.25) V, p = 0.01] was higher in patients with EP mapping while non-selective His bundle bipolar threshold at implant [1.75 (1.0 – 3.0) V vs 1.5 (0.9 – 2.2) V, p = 0.133] and paced QRS duration (116.4 ± 25.4 ms vs 114.4 ± 24.2 ms, p =0.655) were similar. There were no differences in procedural or fluoroscopy time between groups (111 ± 36.9 min vs 107 ± 40.7 min, p = 0.479; and 10.3 ± 8.9 min vs 12.1± 14.0 min, p = 0.328 respectively). There was a similar rate of acute procedural complications (5.2% vs 1.3%, p = 0.076) and patients requiring wound or lead revision (6.8% vs 1.9%, p = 0.115) after a median follow up duration of 205 days (67-397). The prevalence of new onset paroxysmal atrial fibrillation  (11.7% vs 4.2%, p = 0.037) and all cause mortality (12.3% vs 3.2%, p = 0.029) was increased in patients who underwent HBP with EP mapping.

Conclusion

HBP in centers with or without EP mapping showed similar acute procedure success and complication rates. The use of EP mapping system was not shown to affect procedural or fluoroscopy duration.

The impact of impulsivity on weight loss after bariatric surgery: a systematic review

BACKGROUND

Impulsivity has been shown to be associated with obesity through links to pathological eating behavior such as binge eating. The recent literature suggests that impulsivity is linked to poorer outcomes post-bariatric surgery. Impulsivity can be measured in various ways and comprises of three broad domains: impulsive choice, impulsive action, and impulsive personality traits. The aim of this systematic review is to synthesize the current evidence on the impact of impulsivity on post-bariatric surgery weight loss.

METHODS

A literature review was performed in February 2020. Original studies investigating the relationship between impulsivity and weight loss post-bariatric surgery were evaluated.

RESULTS

Ten studies with a total of 1246 patients were analyzed. There were four case-control, four prospective observational and two retrospective observational studies. The postoperative follow-up ranged from 0.5 to 12 years. Eight studies measuring trait impulsivity did not show any association with weight loss post-bariatric surgery, although two studies reported an indirect effect of impulsivity on weight loss mediated via pathological eating behavior. Assessment of impulsive action by two studies showed that post-bariatric surgery weight loss is affected by impulsive action.

CONCLUSION

Impulsivity may adversely affect postoperative outcomes after bariatric surgery. However, this may be specific to state impulsivity or impulsive action rather than trait impulsivity. Patients with a higher state impulsivity may benefit from closer follow-up post-bariatric surgery, as well as cognitive behavioral therapies targeting cognitive control over food.

LEVEL OF EVIDENCE

Level I, systematic review.

A randomised, double-blind, controlled trial on patients undergoing cardiac implantable electronic device implantation with local anaesthesia and sedation with and without pectoral nerve block

Background

Implantation of cardiac implantable electronic devices (CIED) are generally carried out with local anaesthesia (LA) and sedation. However, peri-procedural hypoxaemia and hypotension are well recognised complications of this technique primarily due to sedation effect. The pectoral nerves block (PECs) targets the lateral and median pectoral nerves at interfascial plane between pectoralis major and minor muscles. This technique potentially lower sedation usage and therefore lower sedation-related complications. There is, however, no randomised study to date comparing CIED procedure with and without PECs block.

Methods

We randomly assigned 64 patients undergoing CIED implantation procedure with LA (subcutaneous lignocaine 1%) and sedation (intermittent bolus of intravenous midazolam and fentanyl according to pain score) with (32 patients) and without (32 patients) PECs. Those received PECs with be given 10 mls of 0.25% ropivacaine. Primary endpoint was total dose of sedation used. Secondary endpoints were perioperative incidence of hypoxia, hypotension and hypopnea, perioperative pain scores, proceduralists' and patients' satisfaction scores.

Results

Overall, majority were male (64.1%), mean age of 67.9±10.7 years, mean BMI of 25.7±5.5 kg/m2 and mean lignocaine 1% dosage was 15.3±3.1mL. Compare to those with and without PECs, there was no significant difference in baseline characteristics. The mean fentanyl [25.3±25.0 mcg (95% CI: 16.3–34.3) vs 32.2±26.7 mcg (95% CI: 22.6–41.8), p=0.29] and midazolam dosage [0.7±0.7mg (95% CI: 0.4–0.9) vs 0.8±0.8 (95% CI: 0.6±1.1), p=0.36] were trended lower in PECs compared to without PECs. PECs group had lower pain score at recovery (OR: 1.7, 95% CI: 0.38–7.93, p=0.48). Proceduralists' and patients' satisfaction score were trended higher in PECs compare to non-PECs group. There was no hypoxia, hypotension or hypopnea in both groups.

Conclusion

Patients underwent CIEDs implantation procedure with PECs received lower sedation dosage and lower periprocedure pain score as compare to non-PECs group. Satisfaction score for both proceduralists and patients were trended higher in PECs group compare to non-PECs group.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): Changi General Hospital Research Grant

Effect of direct defect closure during laparoscopic inguinal hernia repair ("TEP/TAPP plus" technique) on post-operative outcomes

PURPOSE

Seroma formation and recurrence in large inguinal hernia still remain an important clinical complication despite decades since the advent of mesh repair.

METHODS

In our prospective comparative analysis, we want to evaluate the effect of direct hernia defect closure on surgical outcomes in patients undergoing laparoscopic inguinal hernia repair in two tertiary care institutions in Singapore. The direct hernia defects were closed with non-absorbable sutures incorporating the pseudosac.

RESULTS

A group of 241 patients underwent laparoscopic inguinal hernia mesh repair for a total of 378 direct defects from April 2014 to July 2018. Of these patients, 98 (40.6%) patients underwent hernia repair without closure of their direct defect while 143 (59.4%) patients underwent direct defect closure. No significant differences were observed between the two patient populations' demographic information and the mean operative time. A total of 219 direct defects were closed and 159 direct defects were not repaired. Compared to the group that did not undergo direct defect closure, the group that had closure of the direct defects demonstrated a statistically significant reduction in recurrence (4.4% versus 0.9%, p = 0.036) and seroma formation (12.6% versus 6.4%, p = 0.045).

CONCLUSION

Direct defect closure has proven to be effective in reducing recurrence and seroma formation post-operatively in patients undergoing laparoscopic inguinal hernia repair. Randomized controlled trials will be required to further evaluate these outcomes.

Multiple Sites of Impingement of a Tracheal Tube as it is Advanced over a Fibreoptic Bronchoscope or Tracheal Tube Introducer in Anaesthetized, Paralysed Patients

Impingement of the tracheal tube on upper airway structures occurs commonly during advancement over a fibreoptic bronchoscope or introducer. In this descriptive study a fibrescope was used to assess the site and mechanism of tracheal tube impingement during advancement over a variety of fibreoptic bronchoscopes and introducers during orotracheal intubation in anaesthetized adults. The effect of the 90° counterclockwise rotation manoeuvre in overcoming impingement was also assessed. We recorded impingement at the right arytenoid, left arytenoid, epiglottis, interarytenoid tissue and the left pyriform fossa. Our study found a wider range of sites at which impingement may occur than in previous studies. We also found that when 90° counterclockwise rotation of the tip of the tracheal tube was achieved, the impingement was reliably overcome.

Ministry of Health clinical practice guidelines: depression

The Ministry of Health (MOH) have updated the clinical practice guidelines on Depression to provide doctors and patients in Singapore with evidence-based treatment for depression. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Depression, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website: http://www.moh.gov.sg/content/moh_web/home/Publications/guidelines/cpg/2012/depression.html. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Neutrophil Gelatinase Associated Lipocalin: An Emerging Biomarker for Acute Kidney Injury in Cardiovascular Disease

Acute kidney injury (AKI) commonly occurs in hospitalised patients resulting in short and long-term morbidity and mortality. A subset of patients especially those with cardiovascular diseases appear particularly vulnerable. The diagnosis of AKI currently depends on changes in serum creatinine and is usually made at least 24 to 48 hours after the initial renal insult. This hinders formulation of possible early therapeutic strategies which could otherwise reduce the clinical sequelae of AKI. Neutrophil gelatinase-associated lipocalin (NGAL) is released in both serum and urine, and has shown great promise in identifying AKI as early as two to four hours after renal injury. NGAL has been demonstrated to be both specific and sensitive in a variety of renal conditions associated with AKI, compared to serum creatinine. This article discusses the emerging role of NGAL in the diagnostic and prognostic evaluation of AKI secondary to cardiovascular diseases and interventions including its benefits and pitfalls. NGAL has been shown to be useful in the diagnosis of AKI particularly for contrast induced nephropathy (CIN) after percutaneous coronary intervention (PCI) and renal dysfunction complicating acute and chronic heart failure. Larger prospective outcome studies with therapeutic interventions are warranted to further validate the role of NGAL in the diagnosis of AKI and in cardiorenal syndrome.

Health-related quality of life and pain assessment in 36 patients with resected pancreas adenocarcinoma: Preliminary analysis

e20692

Background: In order to begin to understand the effects of disease on the patient (pt) and possibly of the pt on the disease, we have begun a systematic psychological inventory of all our pts who have has a pancreatectomy for pancreas adenocarcinoma and have began to correlate this with disease extent, and later with survival. Methods: Prior to post-op discharge home, pts were invited to fill out a brief pain inventory (BPI-SF), BPI interference, emotional (EWB) and physical well-being score (Fact-Hep), as well as social/family and functional well-being (FWB) Fact-Hep. The data was entered into a database, together with pertinent lab results, tumor markers, and tumor characteristics from the pre-op CT scan and post-op pathology report. Data was analyzed by descriptive statistics, frequencies and Pearson Correlation (2-tailed sig). Results: Descriptive means (and ranges) were - tumor size 3.43 cm mean (2.0 min-5.2 max), bilirubin 1.26 (0.2–4.7), albumin 2.69 (1.5–3.6), Hb 10.3 (7.5–13.2), platelets 254K (109K-672K), CEA 4.7 (0.8–24), and Ca 19–9 was 987 (1.0–8127). Pain at presentation pre-op of moderate severity was present in 11% of pts and severe pain was present in 5.6% of pts (16.6% total). Pathologically, LNs were involved by cancer in 50% of pts, vascular invasion in 30%, neural invasion in 35% and any margin positive in 14%. 22% had metastases noted at surgery. Statistically significant correlations were found for tumor size and pain severity (p<.035), platelets and FWB (p<.022), albumin and Hb (p=.000), CA 19–9 and bilirubin (p<.030 i.e. high CA 19–9 and high bilirubin). There was a negative correlation between CEA (but not CA 19–9) and both EWB (p<.039) and FWB (p<.035). Pain severity correlated with depressed mood (p<.010), lower physical well-being (p<.01) and interference with life activities (p<.01). Conclusions: CEA, but not CA 19–9 correlated with both emotional and functional well-being. Baseline pain was present in only 16.6% of this cohort. We plan to follow up to examine how these parameters correlate with pt coping throughout therapy and survival.

No significant financial relationships to disclose.

A safety and efficacy trial of lethally irradiated allogeneic pancreatic tumor cells transfected with the GM-CSF gene in combination with adjuvant chemoradiotherapy for the treatment of adenocarcinoma of the pancreas

3010

Background: Pancreatic cancer remains the fourth leading cause of cancer related deaths in the US in 2006. Surgical resection provides the only possibility of cure. A standard adjuvant treatment approach for patients with resected disease has not yet been determined. We have developed an irradiated GM-CSF transfected allogeneic whole cell line pancreas adenocarcinoma vaccine. We have previously reported a follow-up 60 patient study in this same population using the highest bioactive vaccine dose identified in the initial phase I study. Methods: Single institution phase II study of 60 patients with resected pancreatic adenocarcinoma administered a total of 5 vaccines using two pancreatic cancer cell lines each delivering 2.5 X 10 8 cells ID. Vaccine one was administered 8–10 weeks following surgical resection. Patients subsequently were treated with 5-FU CI based chemotherapy integrated with radiotherapy. Patients who were disease-free one month after completion of chemoradiotherapy received vaccines 2–4, each 1 month apart. A fifth and final booster vaccine was administered 6 months after vaccine 4. The objectives of the study were: 1. To estimate overall survival and disease-free survival in patients with minimal residual disease treated with adjuvant chemoradiotherapy in sequence with the irradiated allogeneic GM-CSF transfected pancreatic tumor cell lines. 2. To characterize toxicities associated with intradermal injections of the vaccine. Results/Conclusions: The study completed enrollment of new patients in January 2005. Median follow-up for these patients is approximately 36 months. 1) The administration of a GM-CSF allogeneic pancreas cancer vaccine is safe and well tolerated; 2) The median survival is approximately 26 months. These results compare favorably with published data for resected pancreas cancer; 3) A matched cohort analysis comparing patients enrolled on this adjuvant vaccine study to the Johns Hopkins Surgery database of patients receiving surgery followed by chemoradiotherapy alone will be presented at this meeting; 4) Immune correlates will be presented at this meeting.

No significant financial relationships to disclose.

027. In vitro growth and maturation: how does this technology fit for clinical application?

Superovulation protocols used in IVF result in multiple eggs that can be fertilized and grown in the laboratory to allow for selection of the best embryo for return to the mother, thereby increasing the chances for a successful pregnancy. However, there are many side effects of these superovulation drug protocols, such as deep vein thrombosis and hyperstimulation. The latter is of particular concern for women with polycystic ovary syndrome. Furthermore, the use of gonadotrophins has been reported to compromise both oocyte quality and the uterine environment and may contribute to the low success rates of IVF. Therefore the ability to collect large numbers of oocytes from women and mature them in vitro is an attractive alternative. However, although there are reports in the literature on extended maturation/culture periods of human oocytes the pregnancy rates are significantly lower than that observed after in vivo maturation. The ability to offer such technology is currently limited by the lack of understanding of how the conditions for in vitro maturation affect the quality of the oocyte and the resulting embryo. Our research is concentrated on establishing the role of metabolic balance in the oocyte for the maintenance of subsequent viability. We have determined that disruptions to the balance between mitochondrial and cytoplasmic metabolism in animal oocytes have significant adverse consequences for the resultant embryo. Changing conditions for in vitro maturation were also found to alter the establishment of the metabolic settings of the oocyte. The ability to determine the role of such parameters in maturing human oocytes will be important for the prospect of adoption of this technology for routine clinical practice.

Nodal signals to Smads through Cripto-dependent and Cripto-independent mechanisms

Nodal ligands are essential for the patterning of chordate embryos. Genetic evidence indicates that EGF-CFC factors are required for Nodal signaling, but the molecular basis for this requirement is unknown. We have investigated the role of Cripto, an EGF-CFC factor, in Nodal signaling. We find that Cripto interacts with the type I receptor ALK4 via the conserved CFC motif in Cripto. Cripto interaction with ALK4 is necessary both for Nodal binding to the ALK4/ActR-IIB receptor complex and for Smad2 activation by Nodal. We also find that Nodal can inhibit BMP signaling by a Cripto-independent mechanism. Inhibition appears to be mediated by heterodimerization between Nodal and BMPs, indicating that antagonism between Nodal and BMPs can occur at the level of dimeric ligand production.

Use of polymerase chain reaction to diagnose a natural outbreak of mouse hepatitis virus infection in nude mice

The enormous cost of eliminating mouse hepatitis virus (MHV) from a mouse colony demands that a confirmed etiologic diagnosis be made to justify the necessary remedial action. We describe an outbreak of MHV in nude mice in which histopathologic findings provided a presumptive diagnosis, but results of serologic testing of affected nude mice and immunocompetent sentinels were negative. Results of transmission electron microscopy of liver specimens from affected mice were equivocal. Confirmation of the etiopathogenesis was eventually provided by reverse transcriptase-polymerase chain reaction (RT-PCR), using primers with nested sequences directed to two separate but highly conserved regions of the MHV genome. This procedure detected MHV in the liver of an affected nude mouse and in a sentinel, although in the latter a positive result was obtained only because of the increased sensitivity of nested primers used in a second round of amplification. Virus was not detected in cell lines that had been injected into the mice, and the source of the outbreak was not found. These results indicate the applicability of RT-PCR for detecting MHV in a field situation while also illustrating that conventional, complementary techniques still have an essential role in reaching a diagnosis. It is recommended that specimens should be taken for histologic examination and serologic testing, as well as for molecular studies when MHV infection is suspected.

Immunohistochemical evaluation of HER-2/neu expression in pancreatic adenocarcinoma and pancreatic intraepithelial neoplasms

Although several morphological and molecular genetic studies have implicated various grades of pancreatic duct hyperplasia as precursor lesions to infiltrating pancreatic adenocarcinoma, the identity of preinvasive pancreatic neoplasms remains controversial. In the present study, the authors examined the expression of the epidermal growth factor receptor homologue, HER-2/neu (c-erbB-2), in pancreatic duct lesions adjacent to infiltrating pancreas cancers in a series of 19 cases of pancreatic duct adenocarcinoma. HER-2/neu expression was examined because it has been identified in a proportion of infiltrating pancreas cancers and because it may provide early neoplasms with a growth advantage over adjacent nonneoplastic epithelium. In normal pancreatic ducts and ductules, HER-2/neu expression was absent in all but one case. By contrast, HER-2/neu was expressed in 82% (P = .008 vs normal ) of ducts with flat mucinous hyperplasia, 86% (P = .03 vs normal) of ducts with papillary mucinous hyperplasia without atypia, 92% (P = .001 vs normal) of ducts with atypical papillary mucinous hyperplasia, and all specimens with carcinoma in situ. HER-2/neu expression was observed in 69% (P = .002 vs normal) of the moderately differentiated infiltrating carcinomas and none of the poorly differentiated infiltrating carcinomas. These data establish HER-2/neu as a potential mediator of growth factor-related signal transduction in pancreatic duct lesions, and provide additional support for the hypothesis that lesions formerly regarded as various grades of hyperplasia instead may represent intraepithelial neoplasms with the potential for subsequent invasion and metastasis.

The role of substance P in the control of gastric acid secretion

Experiments were performed to determine whether substance P plays a physiologic role as an enterogastrone. Basal substance P levels averaged 6.4 +/- 0.2 pg/ml in dogs prepared with gastric and duodenal fistulas. Infusion of substance P at 5 ng/kg/min increased circulating hormone concentrations by more than 1 pg/ml and inhibited pentagastrin-stimulated (4 micrograms/kg/hr) gastric acid secretion by 44% (from 10.9 +/- 1.8 to 6.1 +/- 1.6 mEq/30 min); a similar dose of substance P (7 ng/kg/min) did not alter gastrin levels from the basal level of 19.8 +/- 1.2 fmol/ml. Duodenal acidification (with 0.1N HCl at 5 ml/min for 10 minutes) similarly inhibited pentagastrin-stimulated gastric fistula output (from 8.2 +/- 0.9 to an average of 5.0 +/- 0.9 mEq/30 min for the 30 minutes after irrigation) but did not alter circulating substance P levels. Thus, although physiologic concentrations of substance P inhibit gastric fistula output, this peptide does not seem to be involved in the endogenous acid-mediated duodenal control of acid secretion.