Aptamer proteomics for biomarker discovery in heart failure with reduced ejection fraction

Background

Though current heart failure (HF) biomarkers are highly prognostic, systematically characterizing associations between circulating proteins and risk of subsequent events may improve clinical risk prediction and illuminate new biological pathways. Large-scale assays measuring thousands of proteins now enable unbiased proteomic investigation in clinical trials.

Purpose

To identify and replicate serum proteins associated with HF events in patients with chronic HF with reduced ejection fraction (HFrEF), and to develop and validate a proteomic risk score.

Methods

Serum levels of 4076 proteins were measured at baseline in the ATMOSPHERE (n=1261, 487 events over 6 years) and PARADIGM-HF (n=1257, 287 events over 4 years) trials of chronic HFrEF using a modified aptamer-based proteomics assay. Proteins associated with the primary endpoint, HF hospitalization or cardiovascular death, were identified in the ATMOSPHERE discovery cohort (false discovery rate<0.05) by Cox regression adjusted for age, sex, treatment arm, and anticoagulant use, and replicated in PARADIGM-HF (Bonferroni-corrected p<0.05). A proteomic risk score was derived in ATMOSPHERE using Cox LASSO penalized regression and evaluated in PARADIGM-HF compared to the MAGGIC clinical risk score and N-terminal pro-B-type natriuretic peptide (NT-proBNP). For proteins associated with the primary endpoint, pathway analysis was conducted using Ingenuity Pathway analysis and an exploratory two-sample Mendelian randomization was performed using genetic and outcome data from both trials and protein quantitative trait loci from deCODE to infer which identified proteins contribute to HF prognosis.

Results

We identified 377 serum proteins associated with the primary endpoint in ATMOSPHERE and replicated 167 in PARADIGM-HF. Prognostic proteins included known HF biomarkers Growth Differentiation Factor 15, NT-proBNP, and Angiopoietin-2, and also a previously unrecognized HF biomarker: Sushi, Von Willebrand Factor Type A, EGF And Pentraxin Domain Containing 1 (SVEP1) (HR 1.60 [95% CI 1.44–1.79] per standard deviation [SD], p=2x10–17) (Table 1). Proteins related to hepatic fibrosis, granulocyte adhesion, and inhibition of matrix metalloproteinases were over-represented. A 64-protein risk score derived in ATMOSPHERE predicted clinical events in PARADIGM-HF with greater discrimination (c-statistic 0.70) than the MAGGIC clinical score (c-statistic 0.61), NT-proBNP (c-statistic 0.65), or both (c-statistic 0.66) (Figure 1). Genetically predicted levels of NT-proBNP, WISP2, FSTL1, and CTSS were associated with the primary endpoint by Mendelian randomization.

Conclusions

We identify SVEP1, an extracellular matrix protein known to cause inflammation in vascular smooth muscle cells, as a previously unrecognized HF biomarker. A 64-protein score improved risk discrimination compared with NT-proBNP and may assist in identifying high-risk patients for clinical trials or disease management programs.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): The ATMOSPHERE and PARADIGM-HF trials were sponsored by Novartis

Prognostic implications of NYHA class and NT-proBNP levels in mild heart failure: a PARADIGM-HF analysis

Background

Treatment recommendations for heart failure (HF) with reduced ejection fraction are primarily centered on New York Heart Association (NYHA) classification, such that apparently asymptomatic patients might not be eligible for disease-modifying therapies. NYHA classification, however, may be particularly limited to discriminate mild forms of HF.

Purpose

The present study aimed to determine the relationship between NYHA classification and an objective measure of HF severity (N-terminal pro–B-type natriuretic peptide [NT pro-BNP]), and their association with long-term prognosis in the PARADIGM-HF trial.

Methods

We compared PARADIGM-HF patients classified as NYHA class I, II, and III at randomization (NYHA class IV patients or with unavailable NYHA class were excluded [n=73]). We present kernel density estimation (KDE) plots–a non-parametric way to describe the underlying distribution of a variable–to compare NT-proBNP levels across NYHA classes. Logistic regression and the area under the receiver operating characteristic curve (AUC) were used to assess the ability to predict a patient's NYHA class using NT-proBNP levels. Time-to-event data were calculated with Kaplan–Meier estimates and NYHA class were further stratified by median baseline NT-proBNP (< or ≥1600 pg/ml). The primary outcome was cardiovascular death or first HF hospitalization.

Results

8326 patients were included in this analysis (median age, 64 years; women, 22%; and median left ventricular ejection fraction, 30%). Of 389 patients classified as NYHA class I at randomization, 228 (59%) changed functional class during the first year after randomization. For log-transformed NT-proBNP, KDE overlapped substantially across NYHA classes (Figure 1A). NT-proBNP levels were a poor predictor of NYHA classification: for NYHA class I vs. II, AUC (95% confidence interval [CI]) was 0.51 (0.48–0.54); for NHYA I vs. III, 0.57 (0.54–0.60); and for NYHA II vs. III, 0.56 (0.54–0.57). NYHA class III patients displayed a distinctively higher rate of cardiovascular deaths or first HF hospitalizations (Figure 1B). NYHA class I and II patients revealed lower event rates that were not significantly different (NYHA II vs. I, HR 1.24 [0.97–1.58]). Stratification by NT-proBNP levels identified subgroups with distinctive risk, such that NYHA I patients with high NT-proBNP levels (n=175) had a higher event rate than patients with low NT-proBNP with any NYHA class (Figure 1C).

Conclusion

NYHA class I and II patients overlapped substantially in objective HF measures and long-term prognosis. NYHA classification remains a powerful predictor of cardiovascular events but might be limited to differentiate mild forms of HF, as apparently asymptomatic patients based on physician-defined functional class might become symptomatic within a year and conceal subjects at substantial risk for adverse outcomes.

Funding Acknowledgement

Type of funding sources: None.

Alkaline phosphatase and bilirubin combined are a powerful predictor of outcome in patients with heart failure and reduced ejection fraction: an analysis of the ATMOSPHERE and PARADIGM-HF trials

Introduction

Bilirubin is a recognized predictor of adverse outcomes in patients with heart failure and reduced ejection fraction (HFrEF), possibly because it is a marker of congestion. Alkaline phosphatase (ALP) is an enzyme produced in many tissues including the biliary ducts and elevated levels are also associated with congestion.

Purpose

To examine the prognostic value of ALP alone and in combination with bilirubin in patients with HFrEF.

Methods

The study population was ambulatory patients with HFrEF enrolled in 2 recent clinical trials with similar inclusion and exclusion criteria: ATMOSPHERE (derivation cohort) and PARADIGM-HF (validation). Cut points to define elevated bilirubin and alkaline phosphatase were >17mg/dL and >120 U/L respectively. The composite of cardiovascular death or HF hospitalization, its components, and all-cause death related to elevation of one, other or both of bilirubin and ALP was examined using Cox regression. Univariable and multivariable models with adjustment for other recognized prognostic variables including NT-proBNP were analyzed.

Results

Of 7016 patients with HFrEF enrolled in ATMOSPHERE, 6870 had a measurement of both bilirubin and ALP at baseline: mean age 63 years, 22% women, mean LVEF 28% and proportion NYHA class III/IV 37%. Bilirubin and ALP were both normal in 4810 (70.0%) patients, bilirubin was elevated in 1393 (20.3%), ALP was elevated in 360 (5.2%) and both were elevated in 307 (4.5%) patients. Patients with elevation of both ALP and bilirubin were older, had lower systolic blood pressure, higher heart rate, higher NT-pro BNP, more clinical features of congestion, more atrial fibrillation and a greater proportion were treated with diuretics and digoxin. The primary endpoint rates (per 100 person-years) were 10.4 (95% CI 9.9–11.0) when both markers were normal, 15.1 (13.9–16.4) when bilirubin was elevated, 12.4 (10.4–14.9) when alkaline phosphatase was elevated, and 25.6 (22.0–29.9) when both markers were elevated (Figure 1). The adjusted hazard ratios (95% CI) were (both biomarkers normal = reference): elevated bilirubin 1.19 (1.07–1.31), P=0.001; elevated ALP 1.03 (0.84–1.26), P=0.81; both elevated 1.45 (1.21–1.73), P<0.001. Elevation of both bilirubin and ALP was a significant independent predictor of the components of the primary outcome and all-cause death, the corresponding hazard ratios for all cause death were 1.12 (0.99–1.25), p=0.06; 1.19 (0.96–1.47), p=0.12; and 1.51 (1.25–1.82), p<0.001. These findings were validated in PARADIGM-HF (Table 1).

Conclusions

Elevation of ALP in combination with elevated bilirubin identifies a small group of patients at very high risk of adverse outcomes. This may reflect more significant congestion. ALP and bilirubin, inexpensive and routinely measured biochemical tests, are useful prognostic markers in patients with HFrEF.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship.

P2630Incidence and prognostic impact of new-onset left bundle branch block in patients with heart failure and reduced ejection fraction

Background

Cardiac resynchronization therapy (CRT) improves survival in patients with heart failure, reduced ejection fraction (HFrEF) and left bundle branch block (LBBB). However, little is known about the incidence of LBBB in HFrEF and the risk factors for developing this. We addressed these questions in the PARADIGM-HF and ATMOSPHERE trials.

Methods

We identified 7703 patients with a non-paced rhythm on their baseline ECG, a QRS<130 ms, and at least one follow-up ECG (done at annual visits and end of study). Patients were stratified by baseline QRS duration (≤100 ms - reference; 101–115 ms and 116–129 ms) and followed until development of QRS duration ≥130 ms with a LBBB configuration or latest available ECG. The crude LBBB incidence rate per 100 person-years (py) was identified in the three QRS duration subgroups. Additionally, we examined risk of the primary composite outcome of cardiovascular death or HF hospitalization, and all-cause mortality, in patients with incident LBBB vs. no incident LBBB.

Results

Overall, 313 of 7703 patients (4%) developed LBBB during a mean follow-up of 2.7 years, yielding an incidence rate of 1.5 per 100 py. The rate ranged from 0.9 in those with QRS ≤100 ms to 4.0 per 100 py in patients with QRS 116–129 ms. Other predictors of incident LBBB included male sex, age, lower LVEF, HF duration and absence of AF. The risk of the primary composite endpoint was higher among those who developed incident LBBB vs no incident LBBB; event rates 13.5 vs 10.0 per 100 py, yielding an adjusted HR of 1.43 (1.05–1.96). For all-cause mortality the corresponding rates were 12.6 vs 7.3 per 100 py; HR 1.55 (1.16–2.07) (Table 1).

Table 1. Risk of outcomes according to incident LBBB during follow-up No. events Crude rate per 100py Adjusted* HR (95% CI) HF hospitalization or CV death   No incident LBBB 2145 10.0 (9.6–10.4) 1.00 (ref.)   Incident LBBB 43 13.5 (10.0–18.2) 1.43 (1.05–1.96) All-cause mortality   No incident LBBB 1662 7.3 (6.9–7.6) 1.00 (ref.)   Incident LBBB 48 12.6 (9.5–16.7) 1.55 (1.16–2.07)

Conclusion

Among patients with HFrEF, the annual incidence of new-onset LBBB (and a potential indication for CRT), was around 1.5%, ranging from 1% in those with QRS duration below 100 ms to 4% in those with QRS 116–129 ms. Incident LBBB was associated with a much higher risk of adverse outcomes, highlighting the importance of repeat ECG monitoring in patients with HFrEF.

Acknowledgement/Funding

Novartis

Variations in very preterm birth rates in 30 high-income countries: are valid international comparisons possible using routine data?

OBJECTIVE

Concerns about differences in registration practices across countries have limited the use of routine data for international very preterm birth (VPT) rate comparisons.

DESIGN

Population-based study.

SETTING

Twenty-seven European countries, the United States, Canada and Japan in 2010.

POPULATION

A total of 9 376 252 singleton births.

METHOD

We requested aggregated gestational age data on live births, stillbirths and terminations of pregnancy (TOP) before 32 weeks of gestation, and information on registration practices for these births. We compared VPT rates and assessed the impact of births at 22-23 weeks of gestation, and different criteria for inclusion of stillbirths and TOP on country rates and rankings.

MAIN OUTCOME MEASURES

Singleton very preterm birth rate, defined as singleton stillbirths and live births before 32 completed weeks of gestation per 1000 total births, excluding TOP if identifiable in the data source.

RESULTS

Rates varied from 5.7 to 15.7 per 1000 total births and 4.0 to 11.9 per 1000 live births. Country registration practices were related to percentage of births at 22-23 weeks of gestation (between 1% and 23% of very preterm births) and stillbirths (between 6% and 40% of very preterm births). After excluding births at 22-23 weeks, rate variations remained high and with a few exceptions, country rankings were unchanged.

CONCLUSIONS

International comparisons of very preterm birth rates using routine data should exclude births at 22-23 weeks of gestation and terminations of pregnancy. The persistent large rate variations after these exclusions warrant continued surveillance of VPT rates at 24 weeks and over in high-income countries.

TWEETABLE ABSTRACT

International comparisons of VPT rates should exclude births at 22-23 weeks of gestation and terminations of pregnancy.

Impact of pre-pregnancy diabetes mellitus on congenital anomalies, Canada, 2002-2012

OBJECTIVE

To examine the impact of pre-pregnancy diabetes mellitus (DM) on the population birth prevalence of congenital anomalies in Canada.

METHODS

We carried out a population-based study of all women who delivered in Canadian hospitals (except those in the province of Quebec) between April 2002 and March 2013 and their live-born infants with a birth weight of 500 grams or more and/or a gestational age of 22 weeks or more. Pre-pregnancy type 1 or type 2 DM was identified using ICD-10 diagnostic codes. The association between DM and all congenital anomalies as well as specific congenital anomaly categories was estimated using adjusted odds ratios; the impact was calculated as a population attributable risk percent (PAR%).

RESULTS

There were 118,892 infants with a congenital anomaly among 2,839,680 live births (41.9 per 1000). While the prevalence of any congenital anomaly declined from 50.7 per 1000 live births in 2002/03 to 41.5 per 1000 in 2012/13, the corresponding PAR% for a congenital anomaly related to pre-pregnancy DM rose from 0.6% (95% confidence interval [CI]: 0.4-0.8) to 1.2% (95% CI: 0.9-1.4). Specifically, the PAR% for congenital cardiovascular defects increased from 2.3% (95% CI: 1.7-2.9) to 4.2% (95% CI: 3.5-4.9) and for gastrointestinal defects from 0.8% (95% CI: 0.2-1.9) to 1.4% (95% CI: 0.7-2.6) over the study period.

CONCLUSION

Although there has been a relative decline in the prevalence of congenital anomalies in Canada, the proportion of congenital anomalies due to maternal pre-pregnancy DM has increased. Enhancement of preconception care initiatives for women with DM is recommended.

Amniotic fluid embolism: incidence, risk factors, and impact on perinatal outcome

OBJECTIVE

To extend our previous work on AFE in Canada by including stricter criteria for case identification and by examining risks for stillbirth, neonatal mortality and serious maternal and neonatal morbidity.

DESIGN

Population-based cohort study.

SETTING

Canada.

POPULATION OR SAMPLE

In all, 4,508,462 hospital deliveries from fiscal year 1991/92 to 2008/09.

METHODS

To reduce false-positive diagnoses, we restricted our analysis to AFE cases with cardiac arrest, shock or severe hypertension, respiratory distress, mechanical ventilation, coma, seizure, or coagulation disorder. Linkage of maternal and neonatal records, available since 2001/02, enabled us to examine the effects of AFE on neonatal outcomes. Detailed demographic and clinical data facilitated control for a broad array of potential confounding variables.

MAIN OUTCOME MEASURES

Amniotic fluid embolism, in-hospital neonatal death, asphyxia, mechanical ventilation, bacterial sepsis, seizure, nonimmune haemolytic or traumatic jaundice and length of hospital stay.

RESULTS

A total of 292 AFE cases were identified, of which only 120 (40%) were confirmed after applying our additional diagnostic criteria, yielding an AFE incidence of 2.5 per 100,000 deliveries. Of the 120 confirmed cases, 33 (27%) were fatal. Significant modifiable risk factors included medical induction, caesarean delivery, instrumental vaginal delivery, and uterine or cervical trauma. Amniotic fluid embolism was associated with significantly increased risks of stillbirth and neonatal asphyxia, mechanical ventilation, sepsis, seizures and prolonged length of hospital stay.

CONCLUSIONS

Amniotic fluid embolism remains a rare but serious obstetric outcome, with several important modifiable risk factors and major implications for maternal, fetal and neonatal health.

Investigation of an increase in postpartum haemorrhage in Canada

OBJECTIVE

To investigate the cause of a recent increase in hysterectomies for postpartum haemorrhage in Canada.

DESIGN

Retrospective cohort study.

SETTING

Canada between 1991 and 2004.

POPULATION

All hospital deliveries in Canada as documented in the database of the Canadian Institute for Health Information (excluding incomplete data from Quebec, Manitoba and Nova Scotia).

METHODS

Deliveries with postpartum haemorrhage by subtype were identified using International Classification of Diseases codes, while hysterectomies were identified using procedure codes. Changes in determinants of postpartum haemorrhage (all postpartum haemorrhage and that requiring hysterectomy) were examined, and crude and adjusted period changes were assessed using logistic models.

MAIN OUTCOME MEASURES

Postpartum haemorrhage, postpartum haemorrhage with hysterectomy, postpartum haemorrhage with blood transfusion and postpartum haemorrhage by subtype.

RESULTS

Rates of postpartum haemorrhage increased from 4.1% in 1991 to 5.1% in 2004 (23% increase, 95% CI 20-26%), while rates of postpartum haemorrhage with hysterectomy increased from 24.0 in 1991 to 41.7 per 100,000 deliveries in 2004 (73% increase, 95% CI 27-137%). These increases were because of an increase in atonic postpartum haemorrhage, from 29.4 per 1000 deliveries in 1991 to 39.5 per 1000 deliveries in 2004 (34% increase, 95% CI 31-38%). Adjustment for temporal changes in risk factors did not explain the increase in atonic postpartum haemorrhage but attenuated the increase in atonic postpartum haemorrhage with hysterectomy.

CONCLUSIONS

There has been a recent, unexplained increase in the frequency, and possibly the severity, of atonic postpartum haemorrhage in Canada.

Congenital anomalies ascertained by two record systems run in parallel in the Canadian Province of Alberta

To assess the quality and appropriateness of Canadian Congenital Anomalies Surveillance System (CCASS), a system based on routine hospital admission/separation records, we compared the congenital anomalies ascertained by CCASS for the period of January 1, 1990 to December 31, 1993 in the province of Alberta with corresponding figures obtained from Alberta Congenital Anomalies Surveillance System (ACASS), a specific-purpose surveillance program collecting information on congenital anomalies from multiple sources with mechanisms to evaluate diagnosis. Rates of congenital anomalies estimated by CCASS tended to be higher. Agreement between CCASS and ACASS depended on diagnosis: for the International Clearinghouse for Birth Defects Monitoring System standard categories of congenital anomalies (except for anomalies of abdominal wall), agreement usually exceeded 50%; for less clear-cut diagnoses, it was well below 50%. We conclude that routine medical records can be used for surveillance purposes for major congenital anomalies with clear-cut diagnosis.

Patterns of infant mortality caused by major congenital anomalies

BACKGROUND

We assessed the impact of recent advances in perinatal care on infant mortality due to congenital anomaly.

METHODS

Analysis of trends in congenital anomaly-attributed infant mortality, using the 1981-1995 Statistics Canada's birth and death records, with a total of 2,878,826 live births, 21,883 infant deaths, and 6, 908 infant deaths due to congenital anomalies.

RESULTS

Infant mortality due to major congenital anomaly decreased from 3.11 per 1, 000 live births in 1981 to 1.89 per 1,000 live births in 1995. Cause-specific infant mortality rates for anencephaly, spina bifida, other central nervous system anomalies, cardiovascular system anomalies, respiratory system anomalies, digestive system anomalies, certain musculoskeleton anomalies, urinary system anomalies, chromosomal anomalies, and multiple congenital anomalies were 0.20, 0.23, 0.27, 1.04, 0.24, 0.08, 0.22, 0.16, 0.22, and 0.13 per 1,000 live births, respectively, in 1981-1983, whereas corresponding rates were 0.07, 0.07, 0.18, 0.73, 0.25, 0.03, 0.12, 0.12, 0.26, and 0.06 per 1,000 live births, respectively, in 1993-1995.

CONCLUSIONS

Recent Canadian data show that infant deaths caused by major congenital anomalies have decreased significantly, but reductions varied substantially according to specific forms of anomalies.

Long-term results of sleeve lobectomy for lung cancer

OBJECTIVE

Sleeve lobectomy is a lung saving procedure indicated for central tumors for which the alternative is a pneumonectomy. Current controversies relate to the safety of the procedure and adequacy as a cancer operation. The aim of the study is to analyze long-term survival after sleeve lobectomy, particularly in relation with nodal status and histological type. The incidence and patterns of recurrences were reviewed.

METHODS

From 1972 to 1998, 184 patients (male 152, female 32) underwent sleeve resection for lung cancer. The mean age was 60+/-10 years (11-78 years), and the indications for operation were a central tumor (79%), peripheral tumor with nodal involvement (13%) and compromised pulmonary function (8%). The histological type was predominantly squamous (n=125, 68%), followed by non-squamous (n=50, 27%) and carcinoid tumors (n=9, 5%). Resection was complete in 161 patients (87%).

RESULTS

The operative mortality was 1.6% (n=3). Follow-up was complete for the remaining 181 patients (mean, 5.7 years; range, 1 month-26 years). The survival at 5 and 10 years of all patients was 52 and 33%, respectively. Theses rates for patients with N0 status (n=97) were 63 and 48%, and 48 and 27% for those with N1 status (n=68; N0 vs. N1, P<0.05). An 8% survival rate was observed with N2 status (n=19) at 5 years, with no survivors after 7 years of follow-up. The 5 and 10 year survival was 56 and 34% for squamous carcinoma vs. 33 and 22% for non-squamous carcinoma (P<0.05). These rates were 58 and 38% for complete resection vs. 11 and 6% for incomplete resection at 5 and 10 years, respectively (P<0.05). Local recurrences occurred in 22% of cases, and the prevalence was statistically different between patients with N0 disease (14%) and N1 disease (23%; P=0.03), but not between N1 and N2 disease (42%; P=0.2). When local and distant recurrence were pooled together, the differences were highly significant between N0 (22%) and N1 (41%) disease (P=0.007), and between N0 and N2 (63%) disease (P=0.0002), but not between N1 and N2 disease (P=0.09).

CONCLUSION

Sleeve lobectomy is a safe and effective therapy for patients with resectable lung cancer. The presence of N1 and N2 disease, or of non-squamous carcinoma significantly worsen the prognosis.

Comparison of candesartan, enalapril, and their combination in congestive heart failure: randomized evaluation of strategies for left ventricular dysfunction (RESOLVD) pilot study. The RESOLVD Pilot Study Investigators

BACKGROUND

We investigated the effects of candesartan (an angiotensin II antagonist) alone, enalapril alone, and their combination on exercise tolerance, ventricular function, quality of life (QOL), neurohormone levels, and tolerability in congestive heart failure (CHF).

METHODS AND RESULTS

Seven hundred sixty-eight patients in New York Heart Association functional class (NYHA-FC) II to IV with ejection fraction (EF) <0.40 and a 6-minute walk distance (6MWD) <500 m received either candesartan (4, 8, or 16 mg), candesartan (4 or 8 mg) plus 20 mg of enalapril, or 20 mg of enalapril for 43 weeks. There were no differences among groups with regard to 6MWD, NYHA-FC, or QOL. EF increased (P=NS) more with candesartan-plus-enalapril therapy (0.025+/-0.004) than with candesartan alone (0.015+/-0.004) or enalapril alone(0.015+/-0.005). End-diastolic (EDV) and end-systolic (ESV) volumes increased less with combination therapy (EDV 8+/-4 mL; ESV 1+/-4 mL; P<0.01) than with candesartan alone (EDV 27+/-4 mL; ESV 18+/-3 mL) or enalapril alone (EDV 23+/-7 mL; ESV 14+/-6 mL). Blood pressure decreased with combination therapy (6+/-1/4+/-1 mm Hg) compared with candesartan or enalapril alone (P<0.05). Aldosterone decreased (P<0.05) with combination therapy (23.2+/-5.3 pg/mL) at 17 but not 43 weeks compared with candesartan (0.7+/-7.8 pg/mL) or enalapril (-0.8+/-11. 3 pg/mL). Brain natriuretic peptide decreased with combination therapy (5.8+/-2.7 pmol/L; P<0.01) compared with candesartan (4. 4+/-3.8 pmol/L) and enalapril alone (4.0+/-5.0 pmol/L).

CONCLUSIONS

Candesartan alone was as effective, safe, and tolerable as enalapril. The combination of candesartan and enalapril was more beneficial for preventing left ventricular remodeling than either candesartan or enalapril alone.

Techniques of pneumonectomy. Completion pneumonectomy

Completion pneumonectomy refers to an operation intended to remove what is left of a lung partially resected during previous surgery. Completion pneumonectomy is a technically demanding procedure, which carries an increased operative mortality and morbidity. If the planning and the surgical technique are done meticulously, the good prospect for long-term survival justifies the higher risk.

Birth cohort effects underlying the increasing testicular cancer incidence in Canada

PURPOSE

To examine the pattern of testicular cancer incidence by age, time period and birth cohort since 1969 in Canada.

METHODS

In addition to analyses of the secular trends by age group and birth cohort separately, an age-period-cohort model and the submodels with standard Poisson assumptions were fitted to the data.

RESULTS

The overall age-adjusted incidence of testicular cancer increased in Canada, from 2.8 per 100,000 males in 1969-71 to 4.2 in 1991-93. The younger age groups showed much higher absolute incidence rates in the recent period compared with those in the early period. Age-period-cohort modelling of data restricted to males aged 20-84 years suggested that the observed increase in testicular cancer could be largely attributed to a birth cohort effect. A steady increase in risk was observed among men born since 1945; those born between 1959 and 1968 were 2.0 (95% CI, 1.5-2.6) times as likely to develop testicular cancer as those born between 1904 and 1913.

CONCLUSION

The risk of testicular cancer has increased over time and changing exposure to environmental factors early in life may be responsible for this.

Cardiovascular death and left ventricular remodeling two years after myocardial infarction: baseline predictors and impact of long-term use of captopril: information from the Survival and Ventricular Enlargement (SAVE) trial

BACKGROUND

We quantified cardiovascular death and/or left ventricular (LV) dilatation in patients from the SAVE trial to determine whether dilatation continued beyond 1 year, whether ACE inhibitor therapy attenuated late LV dilatation, and whether any baseline descriptors predicted late dilatation.

METHODS AND RESULTS

Two-dimensional echocardiograms were obtained in 512 patients at 11+/-3 days and 1 and 2 years postinfarction to assess LV size, percentage of the LV that was akinetic/dyskinetic (%AD), and LV shape index. LV function was assessed by radionuclide ejection fraction. Two hundred sixty-three patients (51.4%) sustained cardiovascular death and/or LV diastolic dilatation; 279 (54.5%) had cardiovascular death and/or systolic dilatation. In 373 patients with serial echocardiograms, LV end-diastolic and end-systolic sizes increased progressively from baseline to 2 years (both P<.01). More patients with LV dilatation had a decrease in ejection fraction: 24.8% versus 6.8% (P<.001) (diastole) and 25.7% versus 5.3% (P<.001) (systole). Captopril attenuated diastolic LV dilatation at 2 years (P=.048), but this effect was carried over from the first year of therapy because changes in LV size with captopril beyond 1 year were similar to those with placebo. Predictors of cardiovascular death and/or dilatation were age (P=.023), prior infarction (P<.001), lower ejection fraction (P<.001), angina (P=.007), heart failure (P=.002), LV size (P<.001), and infarct size (%AD) (P<.001).

CONCLUSIONS

Cardiovascular death and/or LV dilatation occurred in >50% of patients by 2 years. LV dilatation is progressive, associated with chamber distortion and deteriorating function that is unaffected by captopril beyond 1 year.

Temporal trends in Canadian birth defects birth prevalences, 1979-1993

The Canadian Congenital Anomalies Surveillance System monitors birth defects reported for stillborns, newborns and infants during the first year of life. Data are available through the 1980s and early 1990s for Ontario, Manitoba and Alberta, and since 1984 for an additional four provinces. Fifty-seven routine monitoring categories and 15 summary categories were examined for temporal trends. Comparing the period 1979-1981 with 1991-1993, the reported birth defect case birth prevalence increased by 0.2% and the total birth defects birth prevalences by 2.5%. The birth prevalence of central nervous system defects decreased by 8.2%; the reported birth prevalence increased for congenital heart defects by 41%, urinary defects by 127%, Down syndrome by 13% and other chromosomal defects by 47%. Further investigation of individual defects would be required to evaluate the degree to which changes in reported birth prevalence reflect changes including the availability and use of specific diagnostic procedures. The work highlights the need to expand the surveillance system to include all affected pregnancies where an anomaly has been detected antenatally.

Temporal trends in Canadian birth defects birth prevalences, 1979-1993

The Canadian Congenital Anomalies Surveillance System monitors birth defects reported for stillborns, newborns and infants during the first year of life. Data are available through the 1980s and early 1990s for Ontario, Manitoba and Alberta, and since 1984 for an additional four provinces. Fifty-seven routine monitoring categories and 15 summary categories were examined for temporal trends. Comparing the period 1979-1981 with 1991-1993, the reported birth defect case birth prevalence increased by 0.2% and the total birth defects birth prevalences by 2.5%. The birth prevalence of central nervous system defects decreased by 8.2%; the reported birth prevalence increased for congenital heart defects by 41%, urinary defects by 127%, Down syndrome by 13% and other chromosomal defects by 47%. Further investigation of individual defects would be required to evaluate the degree to which changes in reported birth prevalence reflect changes including the availability and use of specific diagnostic procedures. The work highlights the need to expand the surveillance system to include all affected pregnancies where an anomaly has been detected antenatally.

Cholesterol and Recurrent Events: a secondary prevention trial for normolipidemic patients. CARE Investigators

Although elevated plasma cholesterol levels represent a well-established and significant risk for developing atherosclerosis, there is a wide spectrum of cholesterol levels in patients with coronary artery disease (CAD). Most secondary prevention studies have generated convincing evidence that cholesterol reduction in patients with high cholesterol levels is associated with improved clinical outcome by reducing risk of further cardiovascular events. However, other risk factors may play a prominent role in the pathogenesis of coronary disease in the majority of patients with near-normal cholesterol values. The Cholesterol and Recurrent Events (CARE) study was designed to address whether the pharmacologic reduction of cholesterol levels with the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, pravastatin, would reduce the sum of fatal coronary artery disease (CAD) and nonfatal myocardial infarction (MI) in patients who have survived an MI yet have a total cholesterol value < 240 mg/dl (< 6.2 mmol/liter). The other inclusion criteria for this study were age 21-75 years, low density lipoprotein (LDL) cholesterol levels of 115-174 mg/dl (3.0-4.5 mmol/liter), and fasting serum triglyceride levels < 350 mg/dl (< 4.0 mmol/liter). A total of 4,159 eligible consenting patients without other study exclusions were then randomly assigned to receive either pravastatin 40 mg daily or matching placebo in addition to their individualized conventional therapy. The trial was designed to have a median follow-up of 5 years. Study endpoints will be evaluated with respect to predefined subgroups according to baseline lipid values, age, gender, prior cardiovascular risk factors, and history.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of DNA methylation by the Ras signaling pathway

We demonstrate that DNA methylation in an adrenocortical tumor cell line, Y1, is controlled by the Ras signaling pathway. Forced expression of a cDNA encoding human GAP120 (hGAP), a down-modulator of Ras activity or delta 9-Jun a transdominant negative mutant of Jun, in Y1 cells reverts the transformed morphology of the cells and results in a reduction in the level of DNA methylation, DNA methyltransferase (MeTase) mRNA, and enzymatic activity. Introduction of an oncogenic Ha-ras into the GAP transfectants results in reversion to a transformed morphology and an increase in the levels of DNA methylation and DNA MeTase activity. Transient transfection CAT assays demonstrate that the expression of DNA MeTase promoter in Y1 cells is regulated by Ras and AP-1. These results establish a molecular link between a major signaling pathway involved in tumorigenesis and DNA methylation.

Regulation of the DNA methyltransferase by the Ras-AP-1 signaling pathway

Using deletion analysis and site-specific mutagenesis to map the 5' regulatory region of the DNA methyltransferase (MeTase) gene, we show that a 106-bp sequence (at -1744 to -1650) bearing three AP-1 sites is responsible for induction of DNA MeTase promoter activity. Using transient cotransfection chloramphenicol acetyl-transferase assays in P19 cells, we show that the DNA MeTase promoter is induced by c-Jun or Ha-Ras but not by a dominant negative mutant of Jun, delta 9. The activation of the DNA MeTase promoter by Jun is inhibited in a ligand dependent manner by the glucocorticoid receptor. Stable expression of Ha-Ras in P19 cells results in induction of transcription of the DNA MeTase mRNA as determined by nuclear run-on assays and the steady state levels of DNA MeTase mRNA as determined by an RNase protection assay. These experiments establish a potential molecular link between nodal cellular signaling pathways and the control of expression of the DNA MeTase gene. This provides us with a possible molecular explanation for the hyperactivation of DNA MeTase in many cancer cells and suggests that DNA MeTase is one possible downstream effector of Ras.

N-terminal proatrial natriuretic factor. An independent predictor of long-term prognosis after myocardial infarction

BACKGROUND

Atrial natriuretic factor (ANF) is a peptide hormone secreted from cardiac atria in response to increased atrial pressure. Because of a longer half-life and greater stability, the N-terminal of ANF prohormone (N-terminal proANF) may be a better integrator of atrial peptide secretion than ANF itself. After myocardial infarction, elevation of ANF and other neurohormones has been associated with a poor prognosis. However, when left ventricular ejection fraction (LVEF) and other important clinical variables are included in multivariate analysis, the independent predictive value of these neurohormones has been reduced markedly.

METHODS AND RESULTS

To test the prognostic value of N-terminal proANF after myocardial infarction, its plasma concentration was measured a mean of 12 days after infarction in 246 patients in the Survival and Ventricular Enlargement (SAVE) Study. N-terminal proANF was a much stronger predictor of survival than ANF itself. Furthermore, in multivariate analysis of cardiovascular mortality and development of heart failure, N-terminal proANF in contrast to ANF and other neurohormones was still a powerful and independent predictor when the model included age, gender, prior myocardial infarction, hypertension, diabetes, use of thrombolysis, Killip class, infarct location, and LVEF.

CONCLUSIONS

The measurement of N-terminal proANF supplements presently used clinical and objective assessments and provides an important independent predictor of prognosis with respect to cardiovascular mortality and development of heart failure.

Indications, risks, and results of completion pneumonectomy

Completion pneumonectomy refers to an operation intended to remove what is left of a lung partially resected during a previous operation. The procedure is seldom indicated and, according to current medical literature, it carries a higher risk of operative mortality and morbidity than does standard pneumonectomy, especially when done for benign disease. Over the past 20 years, 60 consecutive patients aged 17 to 70 years and having a diagnosis of recurrent lung cancer (n = 28), new primary lung cancer (n = 13), or benign pleuropulmonary disease (n = 19) underwent completion pneumonectomy. The mean interval between the first operation and completion pneumonectomy was 30 months for patients with carcinoma and 215 months for patients with benign disease. For all patients, the previous thoracotomy incision was reopened and maneuvers such as rib resection, intrapericardial blood vessel ligation, division of the bronchus first, local application of glues and hemostatic agents, and bronchial reinforcement were routinely used. Six patients died during (n = 2) or after (n = 4) the operation, for an overall operative mortality of 10%. The rate was higher for patients with carcinoma (11.6%) than for patients with benign disease (5.9%). Actuarial 5-year survivals from the time of completion pneumonectomy were 48% for the entire population, 33% for patients with cancer, and 88% for patients with benign disease. These results suggest that completion pneumonectomy can be done with an operative risk similar to the one reported for standard pneumonectomy (6% to 10%). In addition, patients undergoing completion pneumonectomy have a reasonable prospect for long-term survival.

Induction of myogenic differentiation by an expression vector encoding the DNA methyltransferase cDNA sequence in the antisense orientation

To test the hypothesis that DNA methylation controls the state of differentiation of a mammalian cell, we transfected the stable mesenchymal line 10T1/2 with an expression vector encoding sequences from the DNA methyltransferase (DNA MeTase) cDNA in the antisense orientation. 10T1/2 cells transfected with the antisense construct (pZ alpha M), but not with the vector alone, exhibit morphological changes, convert into multinucleated tubular cells, and express the skeletal myosin heavy chain protein. The conversion to myogenic phenotype is a late event and is dependent on the number of replication events that the cell has undergone, suggesting that induction of myogenesis is a multistep process. Demethylation of sequences that are not involved in the myogenic process is detected at early passages, while demethylation and expression of the MyoD gene is a late event. This report establishes for the first time that demethylation is a very early event in commitment to myogenic differentiation, while demethylation and expression of MyoD is a late event. We suggest that other genes serve as the initial targets for demethylation and commitment of mesenchymal cells to myogenesis. The cell lines described in this report can serve as an important system for identifying these genes.

The mouse DNA methyltransferase 5'-region. A unique housekeeping gene promoter

We have cloned and characterized 5'-flanking sequences of the DNA methyltransferase (MeTase) gene. DNA MeTase gene transcription is initiated at a few discrete sites: 343 and 90 base pairs upstream of the translation initiation site as determined by RNase protection and primer extension assays. The promoter sequences that regulate expression of DNA MeTase, as defined by chloramphenicol acetyltransferase assays, reside between position -171 and the transcription start site. The promoter of DNA MeTase does not contain TATAA or CAAT boxes and is unusual because it does not contain the CG-rich elements characteristic of TATAA-less housekeeping genes. The 5'-flanking region of DNA MeTase contains AP-1, AP-2 and glucocorticoid response elements, suggesting possible regulation by cellular signal transduction pathways. The base composition of the DNA MeTase promoter is markedly different from that of other housekeeping genes. Whereas most housekeeping genes are characterized by CG-rich areas in their 5'-flanking regions, the TG dinucleotide is over-represented in DNA MeTase 5'-flanking sequences, including a perfect tandem repeat of T/G between positions -685 and -650. DNA methylation patterns play an important role in the developmental regulation of gene expression in vertebrates. DNA MeTase activity is probably regulated to maintain this pattern of methylation. We suggest that the DNA MeTase promoter represents a new class of housekeeping gene promoters that was designed to ensure high fidelity regulation of gene expression.

Failure of AICA riboside to limit infarct size during acute myocardial infarction in rabbits

This study examined whether the adenosine potentiator, 5-aminoimidazole-4-carboxamide riboside (AICAr), could limit tissue necrosis during acute myocardial infarction in rabbit hearts with minimal coronary collateral flow. Forty-four rabbits underwent 45 min of ischemia with or without coronary reperfusion for 180 min. Five groups were studied. Saline or AICAr (20 mg/kg, i.v.) was administered as a bolus either 10 min before coronary occlusion or 10 min before the onset of coronary reperfusion. The anatomic risk zone size was assessed by radiolabeled microsphere autoradiography and the area of tissue necrosis was defined using the tetrazolium staining method. Coronary collateral flow in the central ischemic zone was assessed using the radiolabeled microsphere technique. No differences were observed for tissue necrosis (normalized to risk zone size) for saline- and AICAr-treated rabbits (66.2 +/- 10.9% vs. 70.8 +/- 19.9%, p = NS) subjected to 45 min of coronary occlusion without reperfusion. Similarly, tissue necrosis in rabbit hearts with 45 min of coronary occlusion followed by 180 min of reperfusion was not significantly reduced when AICAr was administered either 10 min before ischemia or 10 min before reperfusion (79.8 +/- 17.5 and 76.4 +/- 8.1%, respectively) compared to saline-treated controls (68.1 +/- 22.7%). Coronary collateral flow in these hearts was almost nonexistent. The risk zone size and cardiac hemodynamics were similar between the treatment groups. These results demonstrate that AICAr was unable to limit myocyte necrosis when administered either before ischemia or before coronary reperfusion in this experimental preparation of acute myocardial infarction.

Effect of congestive heart failure on the intrinsic metabolic capacity of the liver in the dog

The intrinsic metabolic capacity of the liver at end-stage heart failure in the pacing overdrive dog model of congestive heart failure was evaluated ex vivo. Congestive heart failure was induced in seven adult mongrel dogs (20-30 kg) by cardiac electrical pacing at a frequency of 240 stimuli/min until the development of overt heart failure; seven other dogs served as controls. The animals were then anesthetized and the right ventricular papillary muscles and samples from the left lateral hepatic lobes were collected. The degree of myocardial dysfunction as well as the total amount and the activities of cytochromes P-450 were evaluated. Tension, maximum rate of tension rise, and Vmax were significantly lower (40-60%) in the paced than in the control dogs, indicating a marked myocardial dysfunction. Moreover, significant decreases in total cytochrome P-450 (0.31 +/- 0.04 vs. 0.53 +/- 0.03 nmol/mg of microsomal protein, p less than 0.01) and in the intensity of four different electrophoretic protein bands (molecular masses of 46, 48, 50, and 59 kDa) occurred in the dogs with congestive heart failure. The decrease in total cytochrome P-450 was accompanied by a significant reduction in aminopyrine N-demethylase activity (1.74 +/- 0.25 vs. 2.91 +/- 0.40 nmol/min/mg of microsomal protein, p less than 0.05). Immunoblot analysis using antibodies to two different dog liver phenobarbital-inducible cytochromes P-450 demonstrated that PBD-1 (a P-450IIIA) was not affected by congestive heart failure, whereas PBD-2 (a P-450IIB) was markedly decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Amiodarone antagonizes the effects of T3 at the receptor level: an additional mechanism for its in vivo hypothyroid-like effects

Amiodarone is a diiodinated benzofuran derivative that has some structural similarities to the thyroid hormones and contains two iodine atoms per molecule. It has exhibited hypothyroid-like effects that are thought to be the result of an inhibition of thyroid hormone synthesis due to iodine load, a decrease in the T4 to T3 conversion, and (or) a competitive binding for T3 receptors. The aim of this study was to determine if this third mechanism contributes to the hypothyroid-like effects of amiodarone in vivo. To do so, some characteristic features known to be influenced by hypothyroidism were determined in surgically thyroidectomized rats (n = 48), which received replacement doses of T3 (0.5 and 1.0 microgram.100 g-1.day-1) with or without amiodarone (60 mg.kg-1.day-1). Thyroidectomy produced a hypothyroid state upon which amiodarone had no detectable effects except a negative body weight gain. T3 (0.5 microgram) nearly normalized the thyroid status of the animals, but the concomitant administration of amiodarone induced hypothyroid-like effects suggesting that these effects are dependent on T3. Higher doses of T3 (1.0 microgram) produced hyperthyroid-like effects and attenuated the effects of amiodarone. Unexpectedly, amiodarone decreased T3 plasma concentrations. To determine if the effects of amiodarone were the results of a decrease in T3 plasma and myocardial concentrations or a competition with T3 for its receptors, exogenous T3 pharmacokinetics were studied in thyroidectomized rats receiving T3 (0.5 microgram) with or without amiodarone. The results suggested that amiodarone increased T3 cardiac concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of survival and sudden death in patients with stable severe congestive heart failure due to ischemic and nonischemic causes: a prospective long term study of 200 patients

This prospective study of 200 stable outpatients with New York Hospital Association (NYHA) class III congestive heart failure on maximal medical therapy was done to determine which factors affect survival, to record the incidence of sudden death, and to identify prognostic features which characterize patients at high risk of sudden death. Congestive heart failure was due to coronary artery disease in 151 patients (76%). After an average follow-up of 40 months, 96 patients (48%) had died: 30 (15%) suddenly, 41 (22%) of low output, and 25 (13%) of other causes. Of the 30 patients dying suddenly 12 had autopsies, and acute myocardial infarction was found in nine. Of the 41 patients dying of low output 15 had autopsies, and recent myocardial infarction was found in five. Nine of the 25 patients dying of other causes died of acute myocardial infarction. Multivariate stepwise analysis revealed that severity of ventricular arrhythmias (modified Lown classification), exercise tolerance and left ventricular ejection fraction were the most important determinants of survival. In patients with coronary artery disease, complex ventricular arrhythmias detected by ambulatory Holter monitoring were frequent in all groups and were not clinically useful in predicting which of these patients were at a higher risk of dying suddenly. In contrast, patients without coronary artery disease who died suddenly had a higher incidence of nonsustained ventricular tachycardia and a tendency towards more frequent ventricular arrhythmias in general. The authors conclude that in ambulatory patients with stable NYHA class III heart failure, the severity of ventricular arrhythmias is a predictor of survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Prediction of the left ventricular ejection fraction response to doxorubicin using a multiple linear regression model

The aim of this study was to develop a model for predicting clinically significant deterioration in the left ventricular ejection fraction due to chronic doxorubicin administration. Twenty-six patients were monitored during their courses of doxorubicin chemotherapy with serial gated equilibrium radionuclide angiography. Multiple linear regression analysis was used to derived the best combination of clinical and radionuclide angiographic predictors of resting left ventricular ejection fraction at any point during the course of chemotherapy. The final model consisted of five variables: left ventricular ejection fraction at the previous monitoring point; cumulative dose of doxorubicin achieved at the previous monitoring point; increment in dose from the previous monitoring point; age of the patient; and time to peak left ventricular emptying at the previous monitoring point. The cumulative dose, the ejection fraction at the previous monitoring point and the final model, respectively, explained 11%, 33% and 53% of the variability in ejection fraction determinations during the 26 patient courses. The final model also forecast a potentially very low resting left ventricular ejection fraction (less than 35%) at the cumulative doses of doxorubicin which provoked serious clinical cardiotoxicity in two patients. A multivariate model is a useful aid in timing discontinuation of doxorubicin prior to the development of a clinically significant deterioration in left ventricular ejection fraction.

Role of mediastinoscopy in pretreatment staging of patients with primary lung cancer

Since the introduction of mediastinoscopy, there has been a great deal of discussion regarding indications for this technique and the significance of positive findings. We undertook this study to determine the role of clinical staging and the value of routine mediastinoscopy in the treatment selection of patients with primary lung cancer. From 1975 to 1983, 1,259 consecutive patients with proven and operable lung cancer underwent preresection mediastinoscopy. Nodes were sampled at three levels, and findings were recorded by location, invasiveness, and histology. There were no operative deaths, but 3 patients had a major complication. Mediastinoscopy was positive in 339 (27%) patients and negative in 920 (73%). In the group with positive findings, 303 patients had no operation because a curative resection was not possible (extranodal metastases, 180; location, 76; histology, 47). No patient survived 5 years, and only 4% survived 2 years. Of the 36 patients considered to have operable disease, 28 underwent resection with a projected 5-year survival of 18%. In the group with negative findings, 89% had a curative resection with a hospital mortality of 3.2% and 5-year survival of 53%. When results of mediastinoscopy were correlated with findings at thoracotomy, the sensitivity of the test was 93% on nodes in the superior mediastinum and the specificity, 100%. This study shows that mediastinoscopy is safe and is an accurate indicator of the presence or absence of tumor in superior mediastinal nodes. If positive nodes are found, a curative resection is generally not possible, thoracotomy is avoided, and the overall survival is low.