Impact of the Eurotransplant high-urgency heart allocation system on the outcome of transplant candidates in Germany.

BACKGROUND: In 2000, the Eurotransplant Foundation changed the allocation criteria following the enactment of the German Transplantation Law (GTL). Our study investigated the impact of the new allocation system on outcomes after heart transplantation (HTx) in Germany. METHODS: We compared 2 cohorts of patients who underwent HTx at our institution in two different 3-year periods before (Group 1: 01/1995-12/1997) and after (Group 2: 01/2003-12/2005) implementation of the new system. RESULTS: An increase in the ratio of HTx performed on an urgency basis was found in Group 2 (8.3 % vs. 87.2 %; P < 0.001). The median waiting time and the ischemia time were significantly lower in Group 1 ( P < 0.05). Postoperatively, the length of ICU stay was significantly higher in Group 2 ( P = 0.04). CONCLUSION: The new allocation system decreased the proportion of local and regional organ harvesting. It generates a higher ischemia time without increasing the number of transplantations and without improving the clinical outcome after HTx. The severity of heart failure, rate of secondary organ impairment, and comorbidity is markedly elevated in patients waiting for HTx on HU.

Assessment of basal insulin requirement using fasting tests in insulin-treated patients with type 2 diabetes mellitus.

AIMS: Characterizing the time course of the rise of blood glucose concentrations in the fasting state during the day and night in patients with type 2 diabetes. METHODS: 40 consecutive insulin-treated patients with type 2 diabetes underwent fasting tests on two different days with either no breakfast and lunch (fasting time of 20 hours) or no dinner (fasting time of 21 hours). Glucose-lowering medication was stopped prior to the test according to the half-life of the medication prescribed. At the start of the fasting tests, blood glucose concentrations were lowered to below 7 mmol/L using an insulin infusion. RESULTS: 26 men and 14 women were included in the study. Mean (+/-SD) age was 61+/-10 years, BMI 31+/-7 kg/m (2), and HbA1c 7.5+/-1%. Diabetes duration was 14+/-8 years and duration of insulin therapy had been prescribed for a mean of 6+/-6 years. During the daytime fast, plasma glucose concentrations rose by a mean of 0.8+/-1.6 mmol/L. During the nighttime fast, plasma glucose concentrations increased particularly after midnight, by 4.3+/-2.1 mmol/L, i.e. significantly more than during the daytime fast. CONCLUSIONS: Fasting blood glucose concentrations in the majority of insulin-treated patients with type 2 diabetes increase markedly after midnight. No similar increase is observed during the day. Thus, for most patients with type 2 diabetes, an intermediate- or long-acting insulin injected at bedtime with a peak action six to eight hours after injection should be appropriate.

Heart failure in children -- mechanical assistance.

The use of mechanical circulatory support for the treatment of heart failure in the pediatric population has become increasingly important in pediatric heart surgery units; however, the treatment options for the pediatric population have not attained the same level of technological development as we have seen for the adult population. The use of mechanical assistance as a bridge to transplantation or a bridge to recovery are the main indications for mechanical circulatory support in infants and children. The problem of organ donor shortage is even worse compared to the situation in the field of adult heart transplantations. Especially in Europe however, newly developed pulsatile, paracorporeal ventricular assist devices designed for long-term assist in children have demonstrated their ability to provide excellent results beyond the abilities of extracorporeal membrane oxygenation and centrifugal pumps, which are still the mainstay of mechanical support in children worldwide. Especially in the group of the smallest patients, the use of the most appropriate form of circulatory assistance has to be carefully considered as the co-incidence of respiratory failure as well as other complex physiological situations will severely influence the outcome.

Pre-treatment and post-treatment assessment of the C(6) test in patients with persistent symptoms and a history of Lyme borreliosis.

It was recently reported that antibody to C(6), a peptide that reproduces an invariable region of the VlsE lipoprotein of Borrelia burgdorferi, declined in titer by a factor of four or more in a significant proportion of patients after successful antibiotic treatment of acute localized or disseminated Lyme borreliosis. The present study evaluated the C(6) test as a predictor of therapy outcome in a population of patients with post-treatment Lyme disease syndrome. The serum specimens tested were from patients with well-documented, previously treated Lyme borreliosis who had persistent musculoskeletal or neurocognitive symptoms. All of the patients had participated in a recent double-blind, placebo-controlled antibiotic trial in which serum samples were collected at baseline and 6 months thereafter, i.show $132#e. 3 months following treatment termination. In this patient population no correlation was found between a decline of C(6) antibody titer of any magnitude and treatment or clinical outcome. Antibodies to C(6) persisted in these patients with post-treatment Lyme disease syndrome following treatment, albeit at a markedly lower prevalence and titer than in untreated patients with acute disseminated Lyme disease. The results indicate that C(6) antibody cannot be used to assess treatment outcome or the presence of active infection in this population.

The place of research and the role of academic surgeons in cardiac surgery.

The development of the discipline of cardiac surgery was, to a large extent, guided by the vision and research of its pioneers. On the basis of their efforts, all the different areas of cardiac surgery were able to evolve including coronary artery bypass grafting, heart valve surgery, surgery of the aorta, congenital heart surgery, surgery for rhythm disorders including the implantation of pacemakers and defibrillators, and surgical treatment of advanced heart failure (for example, heart transplantations and mechanical circulatory support). The continued existence of cardiac surgery and its role in medicine in general will depend, to a significant extent, on the future research activities of its protagonists. Cardiac surgeon-scientists will play a pivotal role since they combine clinical experience with scientific knowledge and intuition which make them able to direct research to topics which will matter in the future. However, research costs money, and state or national funds will be not sufficient to support research as much as is necessary. Funding from third parties such as industry will increasingly be required. Due to this, however, the cardiac surgeon-scientist faces various challenges such as the evaluation of his skill in acquiring funds, conflicts with current ethical standards, conflicts of interest when receiving money from industry, and, as a result of the tough competition in this field, the temptation to commit fraud. The head of a department of cardiac surgery holds an important function as his initiative is decisive for the development of visions for the future and for the employment of surgeon-scientists who pursue visionary research. It will take the combined efforts of surgeon-scientists and departmental heads not only to maintain but to extend the position of cardiac surgery in medicine and society even further.

Assessment of selective arterial calcium stimulation and hepatic venous sampling to localize insulin-secreting tumours.

OBJECTIVE: Non-invasive localization modalities such as ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI) often fail to localize insulinomas smaller than 2 cm in diameter. Recent studies have shown that the selective arterial stimulation and hepatic venous sampling (ASVS) technique using intra-arterial calcium as the insulin secretagogue facilitates the regionalization of such occult insulinomas. This study assesses the sensitivity of ASVS in localizing insulin-secreting tumours. SUBJECTS AND METHODS: Eleven consecutive patients (8 women), aged 29-82 years, were studied over the past 4 years at our hospital. Hyperinsulinaemic hypoglycaemia due to an insulin-secreting tumour was proven in all patients. Calcium gluconate (0.025 mEq/kg body weight) was injected directly into the arteries supplying the pancreas and the liver. Insulin levels were measured in samples taken from the right hepatic vein before and 30, 60 and 120 s after each injection. The ASVS technique was performed in all 11 patients; the results were compared with the surgical findings in 10 patients and the autopsy findings in 1 case. The ASVS results were also compared with the findings of other, previously performed imaging modalities. RESULTS: ASVS correctly localized 4 insulin-secreting tumours to the head, 3 to the body, 1 to the tail, 2 to the tail or body of the pancreas and 1 to the liver. Thus, the sensitivity was 100% (11/11) whereas other localization techniques were less sensitive: 7/11 tumours were detected by angiography, 4/8 by endosonography, 3/8 by CT and 1/6 by MRI. Insulinomas (confirmed by histological examination), sized 4-25 mm, were found in 10 patients. All were cured by selective surgery and remained free of hypoglycaemia over the next 1-4 years of follow-up. An insulin-secreting neuroendocrine tumour in the liver was documented in 1 case at autopsy. CONCLUSIONS: Arterial stimulation and hepatic venous sampling is a very sensitive technique for preoperative localization of insulin-producing tumours. It can help to plan minimally invasive surgery and to select an appropriate strategy for patients suffering from malignant tumours in others.

Lung cancer surgery--preoperative risk assessment and patient selection.

Lung resection remains the therapy of choice offering the greatest potential for cure in non spread lung cancer. As these procedures have a significant rate of cardiopulmonary complications, risk assessment and evaluation of functional operability is essential for successful resectional surgery. The most valuable parameters for evaluation of lung function and risk assessment are FEV1, DLCO and VO2max as well as the calculation of predicted postoperative lung function. With preoperative preparatory physical therapy and treatment of comorbidities, also marginal patients may become operable for resectional surgery.

10 Swiss kindreds with multiple endocrine neoplasia type 1: assessment of screening methods.

PRINCIPLES: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disease characterised by the combined occurrence of tumours of the parathyroid glands, the enteropancreatic neuroendocrine system and the anterior pituitary gland. The genetic defect has been mapped to the long arm of chromosome 11q13, and the MEN1-gene was recently identified by positional cloning. Genetic screening for MEN1 germline mutations allows the identification of gene carriers in affected kindreds. Biochemical and radiological screening for MEN1 tumours allows an earlier diagnosis and treatment, and, thus may reduce morbidity and mortality. Since there is no consensus about the frequency and the extent of the necessary screening investigations, evaluation of proposed screening programs is of importance. METHODS: The aims of our study were to identify the MEN1-gene mutations and to detect the gene-carriers in 10 Swiss MEN1 families, as well as to assess biochemical and radiological screening methods. The study included 45 members from 10 MEN1 families. RESULTS: Every family had a different type of MEN1-gene mutation. Thirty out of 45 family members were gene mutation carriers. Twenty-two MEN1-gene carriers had typical MEN1 tumours: parathyroid, enteropancreatic and pituitary tumours were found in 21, 14 and 1 patients, respectively. Applying a defined screening program the following manifestations in asymptomatic MEN1-gene carriers were detected: 9 primary hyperparathyroidism, 3 nonfunctioning pancreatic tumours, 1 gastrinoma, 1 nonfunctioning microadenoma of the pituitary and 1 macronodular adrenal hyperplasia. CONCLUSIONS: The genetic screening facilitates the identification of individuals who carry MEN1-gene mutations, and allows one to exclude non-mutant gene carriers from further investigations. The prospective biochemical and radiological screening of gene mutation carriers allows the earlier detection of MEN1-associated tumours. Therefore, it might be expected that morbidity and mortality of the MEN1 could be reduced.

Comorbidity assessment in hemodialysis and peritoneal dialysis using the index of coexistent disease.

The purpose of this paper is to describe the ICED, summarize outcomes of prior studies in which it was used, and describe the adaptations that have lead to the present instrument. We will then demonstrate its use in quantifying the burden of comorbid conditions in a sample of hemodialysis and peritoneal dialysis patients from our center, and show the relationship between ICED levels and outcomes in peritoneal dialysis patients.

Cytomegalovirus immune globulin after liver transplantation: a cost-effectiveness analysis.

OBJECTIVE: Cytomegalovirus (CMV) immune globulin (CMVIG) has been shown to significantly reduce severe CMV-associated disease complicating orthotopic liver transplant (OLT). We evaluated the economic impact of severe CMV-associated disease and calculated the marginal cost-effectiveness (C/E) of routine prophylaxis with CMVIG after OLT. DESIGN: C/E analysis. SETTING: Four teaching hospitals in Boston. PATIENTS: Patients who underwent OLT from January 1988 through June 1990. MEASUREMENTS: We gathered actual cost data of hospital care for patients enrolled in a clinical trial of CMVIG prophylaxis in OLT. We calculated average outpatient expenses from a separate group of patients undergoing OLT and developed a regression model to estimate costs during the first year post-transplant (R2 = 0.77). Based on this model, we calculated variable costs (in 1999 US dollars) for all patients in the randomized trial. From the published literature we obtained the probability of CMV outcomes and of long-term survival after OLT. We then developed a decision analytical model to determine an incremental C/E ratio, using a Markov simulation to estimate long-term survival and long-term costs. We discounted costs and life-years at 3% and 5% per yr. RESULTS: Based on the efficacy rate of 54% in the controlled trial, we estimate that CMVIG will increase life expectancy by 0.65 discounted years at an additional cost of $11,600, providing a marginal C/E ratio of $17,900/yr life saved. Examining the confidence limits of efficacy, we estimate that CMVIG will have a marginal C/E ratio of $66,200 gained/yr at an efficacy of 11% and $14,000 gained/yr at an efficacy of 83%. CONCLUSION: After OLT, prophylactic CMVIG has an incremental C/E ratio comparable to that of other well-accepted medical therapies and should be used routinely in these patients.

Effects of modification of the allocation system on ischemia duration and costs of heart transplantation. Transplantation Cooperation UNI-NRW.

BACKGROUND: In order to optimize regional utilization of transplantable thoracic organs, the seven university hospitals in North-Rhine-Westfalia have formed a transplant cooperation meanwhile approved by Eurotransplant. METHODS: Heart transplant and organ donation activities of the cooperating hospitals in the year before the foundation of the cooperation (period A, 7/95 - 6/96) and in the year thereafter (period B, 7/96 - 6/97) were retrospectively analysed. RESULTS: In period A, a total of 39 heart transplants and 74 heart donations were performed, whereas in period B 67 heart transplantations and 78 heart donations could be achieved. The regional utilization of the donor organs increased from 4% to 30% with a significantly shorter ischemia time of regionally or locally allocated donor hearts than of nationally or internationally allocated ones. CONCLUSIONS: A high rate of regional or local heart transplant procedures with short ischemia times clearly demonstrate the benefits of a regionalization of heart transplant medicine for medical as well as economical reasons.

Specific cutaneous infiltrates in patients with myelogenous leukemia: a clinicopathologic study of 26 patients with assessment of diagnostic criteria.

BACKGROUND: Few recent studies have analyzed the clinicopathologic features of specific cutaneous manifestations of myelogenous leukemia in a large number of patients. OBJECTIVE: We characterize the clinical and histopathologic spectrum of specific cutaneous manifestations in acute (AML) and chronic (CML) myelogenous leukemia, ascertain further diagnostic criteria, and examine current prognosis. METHODS: Thirty-six lesions of specific cutaneous infiltrates from 26 patients with myelogenous leukemia (AML: 17 patients; M:F = 1:2.4; mean age: 52.6 years; AML-French-American-British [FAB] classification subtypes:M1 = 1, M2 = 3, M4 = 8, M5 = 5. CML = 9 patients; M:F = 4.5:1; mean age: 60.6 years) were retrospectively collected for the study. RESULTS: Cutaneous manifestations presented as solitary or multiple reddish to violaceous papules, plaques, and nodules (17 lesions), or as a generalized erythematous maculopapular eruption (9 lesions). Concurrent extramedullary involvement in other peripheral sites (eg, gums, pharynx, orbits) was observed in 10 patients. Histopathologically, lesions revealed nodular/diffuse infiltrates, often with perivascular and periadnexal accentuation, sparing of the upper papillary dermis, and prominent single arraying of neoplastic cells between collagen bundles. Extension to the subcutis was noted in all deep biopsy specimens (26 lesions). Cytomorphologically, medium to large-sized mononuclear cells (myeloblasts and atypical myelocytes) predominated in AML-M1 and M2, whereas M4 and M5 mainly showed small, medium-sized, or large mononuclear cells with slightly eosinophilic cytoplasm and indented, bi-lobular, or kidney-shaped nuclei (atypical monocytoid cells). In CML, either a variable mixture of mature and immature cells of the granulocytic series (myelocytes, metamyelocytes, eosinophilic metamyelocytes, and neutrophils) or a rather monomorphous infiltrate of mononuclear cells were found. Staining for naphthol AS-D chloroacetate-esterase (NASD) was positive in 24 of 36 lesions (66.6%; AML: 16; CML: 8). Immunohistochemical analysis on paraffin sections using a large panel of antibodies (16 lesions: AML: 13; CML: 3) showed strong reactivity for LCA (CD45), lysozyme, myeloperoxidase (MPD), LN2 (CD74), HLA-DR, and MT1 (CD43) in the majority of cases, and variable staining for monocyte/macrophage markers (KP1/CD68, PGM1/CD68, Mac387, Ki-M1p). The neuronal cell adhesion molecule (NCAM) marker CD56 was reactive in 2 cases of CML, but negative in all cases of AML. MIB1(Ki67) stained 20% to 80% of neoplastic cells. CD34, CD15, CD20, and CD3 were negative in all cases. No correlation between histochemical/immunohistochemical features with type of leukemia or FAB-subtype of AML was observed. All patients with CML and AML with adequate follow-up died within 24 months after onset of skin lesions (mean survival, AML: 7.6 months; CML: 9.4 months). CONCLUSION: Specific cutaneous lesions in AML and CML show distinctive clinicopathologic features that allow diagnosis in most cases. Immunohistochemistry on routinely fixed, paraffin-embedded tissue sections provides useful adjunctive information. Simultaneous expression of lysozyme, MPD, CD45, CD43, and CD74 militates in favor of a diagnosis of specific cutaneous infiltrate of myelogenous leukemia. Pitfalls in immunohistologic diagnosis mainly include lack of expression of some myeloid markers (lysozyme, MPD), and aberrant expression of T-cell markers (eg, CD45RO). Regardless of type of myelogenous leukemia, onset of specific skin manifestations correlates with an aggressive course and short survival.

Selection and outcome of ventricular assist device patients: the Muenster experience.

BACKGROUND: Because the number of patients on the waiting list for transplantation is increasing and the stagnation in the number of organs donated has led to a more restrictive listing for transplantation, an increased fraction of patients needs to be bridged mechanically. We examined the hypothesis that selection of these patients with regard to urgency status is critical in determining outcome. METHODS: A cohort of 631 patients referred for transplantation to our center between January 1, 1990, and December 31, 1996, was analyzed. Two hundred ninety-seven patients were listed for transplantation and 157 were given transplantation. Forty-one patients had to undergo ventricular assist device implantation (n=34, Novacor; n=6, TCI Heartmate; n=1, Medos), 39 for bridging to transplantation and 2 for permanent support. Initial transplantation evaluation data were analyzed in 3 subgroups (elective bridging, urgent bridging, emergency bridging) and compared with another and with other patients referred for transplantation, specifically those who did not have to be bridged on the waiting list. RESULTS: Patients who underwent elective or urgent assist device bridging were younger and more compromised than the rest of patients accepted on the waiting list (higher functional class, lower mean arterial pressure, lower cardiac index, lower serum sodium, higher pulmonary capillary wedge pressure). In the elective group, overall survival including perioperative mortality rate was better than in the urgent/emergency group and at least as good as in patients who were stable on the waiting list and did not undergo heart transplantation during follow-up. This should prompt cardiologists and cardiac surgeons to consider assist device implantation earlier.

The value of breast lumpectomy margin assessment as a predictor of residual tumor burden.

PURPOSE: Margin assessment is commonly used as a guide to the relative aggressiveness of therapy for breast conserving treatment (BCT), though its value as a predictor of the presence, type, or extent of residual tumor has not been conclusively studied. Controversy continues to exist as to what constitutes a margin that is "positive," "close," or "negative." We attempt to address these issues through an analysis of re-excision specimens. PATIENTS AND METHODS: As part of an institutional prospective practice approach for BCT, 265 cases with AJCC Stage I/II carcinoma with an initial excision margin that was < or = 2 mm or indeterminate were subjected to re-excision. The probability of residual tumor (+RE) was evaluated with respect to tumor size, histopathologic subtype, relative closeness of the measured margin, the extent of margin positivity graded as focal, minimal, moderate, or extensive, and the extent of specimen processing as reflected in the number of cut sections per specimen volume (S:V ratio). The amount of residual tumor was graded as microscopic, small, medium, or large. The histopathologic subtype of tumor in the re-excision specimen was classified as having an invasive component (ICa) or pure DCIS (DCIS). RESULTS: The primary excision margin was positive, > 0 < or = 1 mm, 1.1-2 mm, and indeterminate in 60%, 18%, 5%, and 17%, respectively. The predominant histopathologies in the initial excision specimens were invasive ductal (IDC) (50%) and tumors with an extensive intraductal component (EIC) (43%). The histopathology of the initial excision specimen was highly predictive of the histopathology of tumor found on re-excision, as residual DCIS was found in 60% of +RE specimens with initial histopathology of EIC compared to 26% for IDC (p = 0.001). Neither the extent of margin positivity nor the extent of tumor in the re-excision were significantly related to the initial histopathologic subtype; however, a +RE was seen in 59% of EIC, 43% of IDC, and 32% of invasive lobular ILC cases (p = 0.01). The extent of margin positivity was significantly related to the size of the tumor such that tumor size < or = 20 mm was associated with a greater probability of focal or minimal margin involvement. Positive margins graded as focal, minimal, moderate/extensive were associated with a +RE in 26%, 58%, and 84%, respectively (p = 0.001). Further, the extent of positivity was significantly correlated with the extent of residual tumor such that focal/minimal positivity was more commonly associated with micro/small +RE, whereas moderate/extensive positivity was associated with medium/large +RE. When the closest margin of the initial excision specimen was positive, > 0 < or = 1 mm, or 1.1-2 mm, a +RE was found in 56%, 41%, and 17%, respectively (p = 0.01) but did not correlate with the amount of residual tumor. The extent of specimen processing as reflected in the S:V ratio did not correlate with the probability of defining a measured margin as positive nor the probability of a +RE. In a univariate model, the extent of tumor in the re-excision and the histologic type of tumor in the re-excision were significantly associated with margin status and initial histopathology, respectively. The probability of finding a +RE, based on a multivariate model, was associated with the closeness and extent of margin involvement and initial histopathology of an EIC. CONCLUSION: The relative closeness of tumor to the specimen edge and the extent of margin positivity are predictive for residual tumor, though with an error consistent with its limitations as a sampling procedure. The histopathology of tumor in the initial excision is predictive of the type of residual tumor and the extent of margin positivity was correlated with the amount of residual tumor.

Morphologic characterization and assessment of mitral regurgitation after repair of atrioventricular defects in children.

Severe postoperative mitral regurgitation renders information on the underlying mechanism before reoperation very important, as a potential for mitral valve reconstruction may facilitate the decision whether to reoperate, especially in the very young. This study compares the efficacy of transthoracic echo-cardiography (TTE) and left-ventricular angiography with that of transesophageal echocardiography (TEE) for detection of the mechanism underlying mitral regurgitation and its quantitative assessment in children after repair of common atrioventricular septal defect. Five children aged 1.5 to 16 years were evaluated by TTE, TEE, and angiography for postoperative mitral regurgitation 1 to 21 months after initial repair. TEE showed septal detachment of the mitral leaflet in four patients and reopening of the mitral cleft in one patient as the cause of mitral regurgitation whereas TTE failed in four and angiography in all patients. TEE allows definite identification of morphologic characteristics of mitral regurgitation and reliable assessment of its severity. Thus redo surgery may be safety performed on the bases of TEE findings alone without confirmation by cardiac catheterization.

A model to assess severity and impact of fibromyalgia.

OBJECTIVE: To establish a model for the detection of specific factors associated with the severity of symptoms and the impact of fibromyalgia (FM). METHODS: We evaluated 332 consecutive new patients with FM for factors that may be associated with disease severity, assessed by patient global assessment, and function, evaluated by the Fibromyalgia Impact Questionnaire (FIQ). Fifteen potential explanatory factors were evaluated in a multiple linear regression model on data taken from an extensive group of standardized instruments. RESULTS: Of the 15 factors, pain levels, self-assessed inability to work, psychological distress, pending litigation, helplessness, level of education, and coping ability had a significant association with patients' global assessment and with scores on the total FIQ as well as on the activities of daily living subcomponent of the FIQ. CONCLUSION: Disease related factors such as pain and psychological factors such as work status, helplessness, education, and coping ability had an independent and significant relationship to FM symptom severity and function.

Cumulative meta-analysis of clinical trials builds evidence for exemplary medical care.

Cumulative meta-analysis of clinical trials (a Bayesian interpretation for accumulating evidence) will profoundly affect medical care by summarizing evidence in the assessment of technology innovations. Application of the technique to the randomized control trials (RCTs) of streptokinase treatment of acute myocardial infarction, reduction of peri-operative mortality by antibiotic prophylaxis, and prevention of death from bleeding peptic ulcers has revealed efficacy years before it was suspected by any other means. Arrangement of the trials according to event rate in the controls, effect sizes, quality of the trials or according to covariables of interest has supplied unique information. If carried out prospectively the technique supplies invaluable information regarding indications for another trial, the number of patients necessary to determine the validity of past trends, and the type of patients who might be benefitted. Careful examination in a cumulative manner of the prior trials can reduce the need for future large trials.

An assessment of the positive predictive value and cost-effectiveness of dipyridamole myocardial scintigraphy in patients undergoing vascular surgery.

PURPOSE: The approach to cardiac risk stratification of patients undergoing vascular surgery continues to be controversial. The success of algorithms that use clinical risk factors to determine cardiac risk have been inconsistent. Dipyridamole myocardial scintigraphy (DMS) has been accepted as a sensitive, noninvasive approach to risk stratification with excellent negative predictive value. Low positive predictive value (PPV) of abnormal DMS scans is a shortcoming that contributes to extensive preoperative cardiac evaluation and intervention with associated morbidity, mortality, and cost in most patients who undergo uncomplicated vascular procedures, regardless of DMS results. METHODS: Over 6 years, 237 patients underwent DMS before surgical management of infrarenal aortic aneurysm, aortoiliac, or infrainguinal occlusive disease. The value of multiple clinical factors and DMS were assessed retrospectively for the prediction of perioperative myocardial infarction (MI), heart-related death, or preoperative selection for myocardial revascularization. Only congestive heart failure and two or more reversible defects on DMS were statistically significant on logistic regression analysis. RESULTS: The PPV of DMS was 19% for all patients with reversible defects, 12% for patients with one reversible defect, and 36.7% for patients with two or more reversible defects. The rates of cardiac death and MI were 1.3% and 5.9%, respectively. Perioperative echocardiography revealed unchanged postinfarction ejection fraction in most patients who experienced MI. Cost-effectiveness of DMS screening was evaluated. CONCLUSIONS: The costs per MI and cardiac death averted suggest a decline in cost-effectiveness of screening with DMS over time, assuming improving cardioprotective strategies of patient care. Clinical risk factors were minimally useful in the prediction of perioperative MI, heart-related death, or need for myocardial revascularization. The PPV of DMS is low, and the majority of MIs may be clinically insignificant. The cost-effectiveness of cardiac screening with DMS may not be justifiable given current trends of health care reform.

A Bayesian approach to logistic regression models having measurement error following a mixture distribution.

To estimate the parameters in a logistic regression model when the predictors are subject to random or systematic measurement error, we take a Bayesian approach and average the true logistic probability over the conditional posterior distribution of the true value of the predictor given its observed value. We allow this posterior distribution to consist of a mixture when the measurement error distribution changes form with observed exposure. We apply the method to study the risk of alcohol consumption on breast cancer using the Nurses Health Study data. We estimate measurement error from a small subsample where we compare true with reported consumption. Some of the self-reported non-drinkers truly do not drink. The resulting risk estimates differ sharply from those computed by standard logistic regression that ignores measurement error.