0176 Short Sleep Duration and Poor Sleep Quality Predict Blunted Weight Loss in a Behavioral Weight Loss Intervention

Introduction

Short sleep duration and poor sleep quality have each been associated with obesity and weight gain. However, less is known regarding how sleep may impact attempted weight loss. The purpose of this study was to investigate the associations between sleep duration and sleep quality, both independently and in combination, with weight loss in a 12-month behavioral weight loss intervention.

Methods

Young to middle-aged adults who were overweight or obese (N=296) completed a 12-month behavioral weight loss intervention, with weight assessed at baseline, 6 and 12 months. Sleep duration and quality were derived from the Pittsburgh Sleep Quality Index. Analyses examined the change in sleep over time and the association between baseline sleep and changes in sleep with 6- and 12-month weight loss following adjustment for relevant covariates including age, gender, race, education, baseline body mass index, and baseline risk for sleep apnea.

Results

Participants (with an average baseline weight of 97.0±1.0 kg) lost 6.6±1.1 kg (6.8%) and 6.7±1.2 kg (6.9%) at 6 and 12 months relative to baseline, respectively. Global sleep quality significantly improved over the 12-month intervention (P=.03), but average sleep duration and the prevalence of short sleep duration (<6 h) or poor sleep quality did not change significantly (each P≥.45). Adults with short sleep duration at baseline lost 3.3±0.9% less weight than those with ≥6 h sleep duration (P<.001). Adults with poor sleep quality at baseline lost 1.6±0.8% less weight than those with good sleep quality (P=.04). When considered together, adults with both short sleep duration and poor sleep quality lost at least 5.0% less weight compared with all other sleep duration/quality group combinations (P<.001).

Conclusion

Our findings highlight the importance of both sleep duration and sleep quality as predictors of behavioral weight loss and suggest that screening for sleep disturbance may be useful to determine who may benefit from additional counseling and resources.

Support

R01HL077525, K23HL118318

The Influence of Race and Common Genetic Variations on Outcomes After Pediatric Heart Transplantation

Significant racial disparity remains in the incidence of unfavorable outcomes following heart transplantation. We sought to determine which pediatric posttransplantation outcomes differ by race and whether these can be explained by recipient demographic, clinical, and genetic attributes. Data were collected for 80 black and 450 nonblack pediatric recipients transplanted at 1 of 6 centers between 1993 and 2008. Genotyping was performed for 20 candidate genes. Average follow-up was 6.25 years. Unadjusted 5-year rates for death (p = 0.001), graft loss (p = 0.015), acute rejection with severe hemodynamic compromise (p = 0.001), late rejection (p = 0.005), and late rejection with hemodynamic compromise (p = 0.004) were significantly higher among blacks compared with nonblacks. Black recipients were more likely to be older at the time of transplantation (p < 0.001), suffer from cardiomyopathy (p = 0.004), and have public insurance (p < 0.001), and were less likely to undergo induction therapy (p = 0.0039). In multivariate regression models adjusting for age, sex, cardiac diagnosis, insurance status, and genetic variations, black race remained a significant risk factor for all the above outcomes. These clinical and genetic variables explained only 8-19% of the excess risk observed for black recipients. We have confirmed racial differences in survival, graft loss, and several rejection outcomes following heart transplantation in children, which could not be fully explained by differences in recipient attributes.

Gestational weight gain, prepregnancy body mass index and offspring attention-deficit hyperactivity disorder symptoms and behaviour at age 10

OBJECTIVE

To assess offspring attention-deficit hyperactivity disorder (ADHD) symptoms and emotional/behavioural impairments at age 10 years in relation to maternal gestational weight gain (GWG) and prepregnancy body mass index (BMI).

DESIGN AND SETTING

Longitudinal birth cohort from Magee-Womens Hospital, Pittsburgh, Pennsylvania (enrolled 1983-86).

POPULATION

Mother-infant dyads (n = 511) were followed through pregnancy to 10 years.

METHODS

Self-reported total GWG was converted to gestational-age-standardised z-scores. Multivariable linear and negative binomial regressions were used to estimate effects of GWG and BMI on outcomes.

MAIN OUTCOME MEASURES

Child ADHD symptoms were assessed with the Conners' Continuous Performance Test. Child behaviour was assessed by parent and teacher ratings on the Child Behaviour Checklist (CBCL) and Teacher Report Form, respectively.

RESULTS

The mean (SD) total GWG (kg) was 14.5 (5.9), and 10% of women had a pregravid BMI ≥30 kg/m² . Prepregnancy obesity (BMI of 30 kg/m² ) was associated with increased offspring problem behaviours including internalising behaviours (adjusted β 3.3 points, 95% CI 1.7-4.9), externalising behaviours (adjusted β 2.9 points, 95% CI 1.4-4.6), and attention problems (adjusted β 2.3 points, 95% CI 1.1-3.4) on the CBCL, compared with normal weight mothers (BMI of 22 kg/m² ). There were nonsignificant trends towards increased offspring impulsivity with low GWG among lean mothers (adjusted incidence rate ratio 1.2, 95% CI 0.9-1.5) and high GWG among overweight mothers (adjusted incidence rate ratio 1.7, 95% CI 0.9-2.8), but additional outcomes did not differ by GWG z-score. Results were not meaningfully different after excluding high-substance users.

CONCLUSIONS

In a low-income and high-risk sample, we observed a small increase in child behaviour problems among children of obese mothers, which could have an impact on child behaviour in the population.

TWEETABLE ABSTRACT

Maternal obesity is associated with a small increase in child behaviour problems.

Gestational weight gain and the risk of offspring obesity at 10 and 16 years: a prospective cohort study in low-income women

OBJECTIVE

To study the association between gestational weight gain (GWG) and offspring obesity risk at ages chosen to approximate prepuberty (10 years) and postpuberty (16 years).

DESIGN

Prospective pregnancy cohort.

SETTING

Pittsburgh, PA, USA.

SAMPLE

Low-income pregnant women (n = 514) receiving prenatal care at an obstetric residency clinic and their singleton offspring.

METHODS

Gestational weight gain was classified based on maternal GWG-for-gestational-age Z-score charts and was modelled using flexible spline terms in modified multivariable Poisson regression models.

MAIN OUTCOME MEASURES

Obesity at 10 or 16 years, defined as body mass index (BMI) Z-scores ≥95th centile of the 2000 CDC references, based on measured height and weight.

RESULTS

The prevalence of offspring obesity was 20% at 10 years and 22% at 16 years. In the overall sample, the risk of offspring obesity at 10 and 16 years increased when GWG exceeded a GWG Z-score of 0 SD (equivalent to 30 kg at 40 weeks); but for gains below a Z-score of 0 SD there was no relationship with child obesity risk. The association between GWG and offspring obesity varied by prepregnancy BMI. Among mothers with a pregravid BMI <25 kg/m(2) , the risk of offspring obesity increased when GWG Z-score exceeded 0 SD, yet among overweight women (BMI ≥25 kg/m(2) ), there was no association between GWG Z-scores and offspring obesity risk.

CONCLUSIONS

Among lean women, higher GWG may have lasting effects on offspring obesity risk.

THE PENETRATION OF CATIONS INTO LIVING CELLS

Direct tests of the cell sap of Nitella show that the protoplasm is normally permeable to Li, Cs, and Sr, and that penetration is more rapid in an unbalanced than in a balanced solution.

COMPARATIVE STUDIES ON RESPIRATION : XIV. ANTAGONISTIC ACTION OF LANTHANUM AS RELATED TO RESPIRATION

1. Concentrations of La(NO₃)₃ up to 0.000025 M have little effect upon the rate of respiration of Bacillus subtilis; at 0.000006 M there is an increase in rate, while in higher concentrations there is a decrease in rate. 2. There is well marked antagonism between La(NO₃)₃ and NaCl, and very slight antagonism between La(NO₃)₃ and CaCl₂. 3. It requires a very small amount of La(NO₃)₃ to antagonize NaCl, the proportions of the two salts at their maximum antagonism being 99.8 parts of NaCl and 0.2 parts of La(NO₃)₃.

COMPARATIVE STUDIES ON RESPIRATION : VIII. THE RESPIRATION OF BACILLUS SUBTILIS IN RELATION TO ANTAGONISM

1. In relatively low concentrations of NaCl, KCl, and CaCl₂ the rate of respiration of Bacillus subtilis remains fairly constant for a period of several hours, while in the higher concentrations, there is a gradual decrease in the rate. 2. NaCl and KCl increase the rate of respiration of Bacillus subtilis somewhat at concentrations of 0.15 M and 0.2 M respectively; in sufficiently high concentrations they decrease the rate. CaCl₂ increases the rate of respiration of Bacillus subtilis at a concentration of 0.05 M and decreases the rate at somewhat higher concentrations. 3. The effects of salts upon respiration show a well marked antagonism between NaCl and CaCl₂, and between KCl and CaCl₂. The antagonism between NaCl and KCl is slight and the antagonism curve shows two maxima.

THE EFFECT OF HYDROGEN ION CONCENTRATION ON THE PRODUCTION OF CARBON DIOXIDE BY BACILLUS BUTYRICUS AND BACILLUS SUBTILIS

1. The maximum rate of CO₂ production of Bacillus butyricus was found to be at a pH value of 7; of Bacillus subtilis at pH 6.8. If the pH value be raised or lowered there is a progressive decrease in the rate of production of CO₂. 2. Spontaneous recovery follows the addition of alkali to either organism, while addition of acid is followed by recovery only upon addition of an equivalent amount of alkali, and is not complete except when the amount of acid is very small.

Outcomes of patients with chronic renal insufficiency in the bypass angioplasty revascularization investigation

BACKGROUND

Although severe chronic kidney disease (CKD) is an independent predictor of mortality among patients with coronary artery disease, the impact of mild CKD on morbidity and mortality has not been fully defined.

METHODS AND RESULTS

Morbidity and mortality for the 3608 patients with multivessel coronary artery disease enrolled in the Bypass Angioplasty Revascularization Investigation randomized trial and registry were compared on the basis of the presence and absence of CKD, defined as a preprocedure serum creatinine level of >1.5 mg/dL. Seventy-six patients had CKD. Patients with renal insufficiency were older and more likely to have a history of diabetes, hypertension, and other comorbidities. Among patients undergoing PTCA, patients with CKD had a greater frequency of in-hospital death and cardiogenic shock (P<0.05 and 0.01, respectively). There was a trend toward a larger proportion of patients with CKD experiencing angina at 5 years (P=0.079). Patients with CKD had more cardiac admissions (P=0.003 and <0.0001 for patients undergoing PTCA and CABG, respectively) and a shorter time to subsequent CABG after initial revascularization than patients without CKD (P=0.01). CKD was associated with a higher risk of death at 7 years, both of all causes (relative risk 2.2, P<0.001) and of cardiac causes (relative risk 2.8, P<0.001).

CONCLUSIONS

CKD is associated with an increased risk of recurrent hospitalization, subsequent CABG, and mortality. This increased risk of death is independent of and additive to the risk associated with diabetes.

Outcomes of noncardiac surgery after coronary bypass surgery or coronary angioplasty in the Bypass Angioplasty Revascularization Investigation (BARI)

PURPOSE

Previous studies have shown that coronary artery bypass surgery reduces the risk of cardiac complications after noncardiac surgery. Whether coronary angioplasty provides equivalent protection is not known.

SUBJECTS AND METHODS

Patients were randomly assigned to undergo cardiac artery bypass surgery or angioplasty as part of the Bypass Angioplasty Revascularization Investigation trial. All subsequent noncardiac surgeries during a mean (+/- SD) follow-up of 7.7 years were recorded among participants in the ancillary Study of Economics and Quality of Life. Rates of mortality and nonfatal myocardial infarction, length of stay, and hospital costs were compared by the original randomized assignment.

RESULTS

A total of 501 patients had noncardiac surgery at a median of 29 months after their most recent coronary revascularization procedure. Mortality and nonfatal myocardial infarction within 30 days of the first noncardiac surgery occurred in 4 of the 250 of the surgery-assigned patients and in 4 of the 251 of the angioplasty-assigned patients (P = 1.0). There were no significant differences in the mean length of hospital stay (6.3 +/- 6.7 versus 6.2 +/- 6.8 days; P = 0.47) or hospital cost ($8,920 +/- $11,511 versus $7,785 +/- $7,643; P = 0.33) between the surgery and angioplasty groups. Similar results were obtained when subsequent noncardiac procedures were included in the analysis.

CONCLUSION

Rates of myocardial infarction and death after noncardiac surgery are similarly low after contemporary bypass surgery or angioplasty in patients with multivessel coronary artery disease.

Similarity of ventricular function in patients alive 5 years after randomization to surgery or angioplasty in the BARI trial

BACKGROUND

Left ventricular ejection fraction (LVEF) is a recognized determinant of survival in patients with coronary artery disease. In major trials comparing surgical and percutaneous revascularization approaches, the long-term effect of the coronary revascularization strategy on LVEF has not been reported.

METHODS AND RESULTS

In the NHLBI-sponsored Bypass and Angioplasty Revascularization Investigation (BARI) randomized trial comparing angioplasty and bypass surgery as initial treatment strategies, 1220 (75%) of the 1617 surviving randomized patients had their EF measured by radionuclide ventriculography 5 years after study entry. For the total study group, the 5-year EF in the CABG group (n=623) was 55.8+/-12.3, compared with 55.7+/-12.7 in PTCA group (n=597, P:=0.82). There was no significant difference in measured EF between the CABG group and the PTCA group within multiple subgroups determined by the presence or absence of diabetes, 3-vessel disease, complete revascularization, or prior myocardial infarction. In a multiple linear regression model developed to predict 5-year EF, treatment assignment to PTCA or CABG was not significant (P:=0.95). If an EF of 0 was imputed for patients who were dead and missing EF data, however, there was a higher EF in the CABG group (P:=0.0018) among diabetic patients only.

CONCLUSIONS

In the BARI randomized trial, initial treatment assignment to angioplasty was not associated with any difference in long-term ventricular function compared with initial treatment assignment to surgery. These results apply, however, only to patients who were alive at 5 years.

Long-term clinical outcome in the Bypass Angioplasty Revascularization Investigation Registry: comparison with the randomized trial. BARI Investigators

BACKGROUND

The Bypass Angioplasty Revascularization Investigation (BARI) included 4039 patients with multivessel coronary artery disease; 1829 consented to randomization, and 2010 did not but were followed up in a registry. Thus, we can evaluate the outcome of physician-guided versus random assignment of percutaneous transluminal coronary angioplasty (PTCA) versus coronary artery bypass graft surgery (CABG).

METHODS AND RESULTS

We compared the baseline features and outcomes for PTCA and CABG in the overall registry and its predesignated subgroups. We assessed the impact of treatment by choice versus random assignment by comparing the results in the registry with those of the randomized trial. Statistical adjustments for differences in baseline characteristics were made. Within the registry, nearly twice as many patients were selected for PTCA (1189) as CABG (625); mortality at 7 years was similar for PTCA (13.9%) and CABG (14.2%) (P=0.66) before and after adjustment for baseline differences between patients selected for PTCA versus CABG (adjusted RR, 1.02; P=0.86). In contrast to the randomized trial, the 7-year mortality rate of treated diabetics in the registry was equally high (26%) with PTCA or CABG. Seven-year mortality was higher for patients undergoing PTCA in the randomized trial than in the registry (19.1% versus 13.9%, P<0.01) but not for those undergoing CABG (15.6% versus 14.2%, P=0.57). The adjusted relative mortality risk for PTCA in the randomized versus registry population was 1.17 (P=0.16).

CONCLUSIONS

BARI physicians were able to select PTCA rather than CABG for 65% of registry patients who underwent revascularization without compromising long-term survival either in the overall population or in treated diabetics.

Nocturia in adults: etiology and classification

Nocturia is one of the most bothersome of all urologic symptoms, yet even a rudimentary classification does not exist. We herein propose a classification system of nocturia based on a retrospective study. The records of 200 consecutive patients with nocturia were reviewed. Evaluation included history, micturition diary (including day, night, and 24-hr voided volume), postvoid residual urine (PVR), and videourodynamic study (VUDS). Functional bladder capacity (FBC) was determined to be the largest voided volume in a 24-hr period. The etiology of nocturia was thus classified into one of three groups: nocturnal polyuria ([NP] in which voided urine volume during the hours of sleep exceeds 35% of the 24-hr output), nocturnal detrusor overactivity ([NDO] defined as nocturia attributable to diminished bladder capacity during the hours of sleep), and mixed (NP+NDO); polyuria (24-hr urine output >2,500 cc) was classified separately. There were 129 women and 65 men ranging in age from 17 to 94 years (x=59). Overall 13 (7%) had NP, 111 (57%) NDO, and 70 (36%) had a mixed etiology of their nocturia (both NP and NDO). Forty-five (23%) also had polyuria. These data confirm that the etiology of nocturia is multifactorial and in many instances unrelated to the underlying urologic condition. Nocturnal overproduction of urine is a significant component of nocturia in 43% of patients, most of whom will also have NDO. We believe that treatment should be directed at both conditions.

Predictors of mortality and mortality from cardiac causes in the bypass angioplasty revascularization investigation (BARI) randomized trial and registry. For the BARI Investigators

BACKGROUND

The impact of percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) on long-term mortality rates in the presence of various demographic, clinical, and angiographic factors is uncertain in the population of patients suitable for both procedures.

METHODS AND RESULTS

In the Bypass Angioplasty Revascularization Investigation (BARI) randomized trial and registry, 3610 patients who were eligible to receive PTCA and CABG were revascularized between 1989 and 1992. Multivariate Cox models were used to identify factors associated with 5-year mortality and cardiac mortality, with particular attention to factors that interact with treatment. Diabetic patients receiving insulin had higher mortality and cardiac mortality rates with PTCA compared with CABG (relative risk [RR] 1.78 and 2.63, respectively, P<0.001), and patients with ST elevation had higher cardiac mortality rates with CABG than with PTCA (RR 4.08, P<0.001). Factors most strongly associated with high overall mortality rates were insulin-treated diabetes, congestive heart failure, kidney failure, and older age. Black race was also associated with higher mortality rates (RR 1.49, P=0.019).

CONCLUSIONS

A set of variables was identified that could be used to help select a revascularization procedure and to evaluate risk of long-term mortality in the population of patients considering revascularization.

The effect of previous coronary-artery bypass surgery on the prognosis of patients with diabetes who have acute myocardial infarction. Bypass Angioplasty Revascularization Investigation Investigators

BACKGROUND

Acute myocardial infarction in patients with diabetes is associated with high mortality. We studied whether previous revascularization by coronary-artery bypass grafting (CABG), as compared with percutaneous transluminal coronary angioplasty (PTCA), influences the prognosis in such patients.

METHODS

We classified all patients eligible for the Bypass Angioplasty Revascularization Investigation who underwent coronary revascularization within three months after entry into the study according to whether they had diabetes and whether they had undergone CABG, either initially or after PTCA. The protective effect of CABG with regard to mortality in the presence and in the absence of subsequent spontaneous Q-wave myocardial infarction was estimated with the use of Cox regression models.

RESULTS

Among the 641 patients with diabetes and the 2962 without diabetes, the cumulative five-year rates of death were 20 percent and 8 percent, respectively (P<0.001), and the five-year rates of spontaneous Q-wave myocardial infarction were 8 percent and 4 percent (P<0.001). CABG greatly reduced the risk of death after spontaneous Q-wave myocardial infarction in the patients with diabetes (relative risk, 0.09; 95 percent confidence interval, 0.03 to 0.29). Among patients with diabetes who had undergone CABG but did not have spontaneous Q-wave myocardial infarctions, the corresponding relative risk of death was 0.65 (95 percent confidence interval, 0.45 to 0.94). Among the patients without diabetes, no protective effect of CABG was evident.

CONCLUSIONS

Among patients with diabetes, previous coronary bypass surgery, as compared with coronary angioplasty, has a highly favorable influence on prognosis after acute myocardial infarction and a smaller beneficial effect among patients who do not have infarction. These findings should influence the type of coronary revascularization procedure selected for patients with diabetes who have multivessel coronary artery disease.

Quality of life after coronary revascularization in the United States and Canada

Cardiac procedures are performed less frequently in Canada than in the United States (US), yet rates of cardiac death and myocardial infarction are similar. We therefore sought to compare long-term symptoms and quality of life in Canadian and American patients undergoing initial coronary revascularization. The 161 patients enrolled in the Bypass Angioplasty Revascularization Investigation at the Montreal Heart Institute were compared with 934 patients enrolled at 7 US sites. Patients' outcomes were documented for 5 years after random assignment to percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery. Functional status was assessed using the Duke Activity Status Index. Canadian patients were significantly younger and had more angina at study entry. Death and nonfatal myocardial infarction were not significantly different between Canadian and US patients after adjustment for baseline risk. Canadian patients had significantly greater improvements in functional status at 1-year follow-up (Duke Activity Status Index score + 13.5 vs. + 6.0, p = 0.002), but this difference progressively narrowed over 5 years. Angina was equally prevalent in Canadian and US patients at 1 year (16% vs. 19%), but significantly more prevalent in Canadian patients at 5 years (36% vs. 16%, p = 0.001). Repeat revascularization procedures were performed less often over 5 years among Canadian patients (26% vs. 34%, p = 0.08), especially coronary artery bypass graft surgery after initial percutaneous transluminal coronary angioplasty (18% vs. 32%, p = 0.03). These results suggest more anginal symptoms are required in Canada before coronary revascularization, but as a result Canadians receive greater improvements in quality of life after the procedure.

The design, patient population and outcomes from the Bypass Angioplasty Revascularization Investigation (BARI) randomized trial and registries

The Bypass Angioplasty Revascularization Investigation (BARI) was designed to compare CAGB and PTCA for patients with symptomatic multivessel coronary artery disease. The randomized trial reported significant differences in 7-year survival favouring CABG. However, for the 353 patients with treated diabetes mellitus, an overwhelming benefit associated with CABG was seen (mortality: 23.6% CABG vs 44. 3% PTCA, p=0.0011), whilst no treatment difference was observed for the 1476 non-diabetic patients (13.6% CABG vs 13.2% PTCA, p=0.72). Patients assigned to PTCA experienced fewer in-hospital Q-wave MIs, but these patients received more revascularization procedures and more often had angina during follow-up.

Prognostic importance of lower extremity arterial disease in patients undergoing coronary revascularization in the Bypass Angioplasty Revascularization Investigation (BARI)

OBJECTIVES

The purpose of this study was to evaluate the prevalence and prognostic importance of lower extremity arterial disease (LEAD) in patients with multivessel coronary artery disease.

BACKGROUND

The presence of clinically evident LEAD increases the risk of death in patients with known coronary artery disease. Because studies have lacked noninvasive measures of subclinical LEAD, the true prognostic importance of lower extremity atherosclerosis in this population has probably been underestimated.

METHODS

Ankle blood pressures were measured in 405 consecutive patients with angiographically documented multivessel coronary disease from seven Bypass Angioplasty Revascularization Investigation (BARI) sites and a parallel study site within 3 years of enrollment. Lower extremity arterial disease was defined as an ankle/arm systolic blood pressure ratio of 0.90 or less.

RESULTS

Among patients studied, 69 (17%) had LEAD. These patients were more likely to be current smokers, treated for diabetes, older and present with unstable angina compared with patients without LEAD. Among patients who underwent coronary arterial bypass grafting, major complications occurred in 2.8% of those without LEAD compared with 20.7% of those with LEAD (p = 0.002). Five-year mortality rates were similar for symptomatic LEAD (14%) and asymptomatic LEAD (14%). Patients without LEAD had a 3% mortality. After adjusting for baseline differences, the relative risk of death was 4.9 times greater for patients with LEAD compared with those without (95% confidence interval [CI]: 1.8, 13.4, p < 0.01).

CONCLUSIONS

Patients with LEAD have a significantly higher risk of death than patients without LEAD, regardless of the presence of symptoms. An abnormal ankle/arm index is a strong predictor of mortality and can be used to further stratify risk among patients with multivessel coronary artery disease.

Clinical correlates of the initial and long-term cost of coronary bypass surgery and coronary angioplasty

BACKGROUND

Medical costs vary substantially among patients. Understanding the baseline factors that predict subsequent cost may allow better selection of therapy for individual patients. Understanding the postprocedure events that increase cost should help to improve efficiency and effectiveness of coronary revascularization.

METHODS

Data on 4-year costs were collected from patients randomly assigned to coronary angioplasty or bypass surgery as part of the BARI (Bypass Angioplasty Revascularization Investigation) trial. Regression models first examined factors known at the time of randomization that prospectively predicted initial procedure cost and long-term cost. Subsequent models tested the value of postrandomization events as explanatory variables for cost.

RESULTS

The independent baseline predictors of higher initial percutaneous transluminal coronary angioplasty cost included 3-vessel disease (+12%) and acute presentations (+22%), whereas the independent predictors of higher initial coronary artery bypass grafting cost included the number of comorbid conditions (+5% per condition) and female sex (+7%). The independent baseline predictors of 4-year cost included heart failure (+26%), diabetes (+22%), comorbidity (+10%), and angioplasty assignment in patients with 2-vessel disease (-15%). Postrandomization models showed higher initial and long-term costs were strongly correlated with the number of repeat revascularization procedures (+30% to +128%) and the occurrence of clinical complications (+8% to +131%).

CONCLUSIONS

Two-vessel disease identifies patients likely to have lower costs after angioplasty, whereas heart failure, comorbid conditions, and diabetes identify patients likely to accrue higher costs after either angioplasty or bypass surgery. Long-term costs can be potentially reduced by interventions that decrease procedural complications or reduce the need for repeat revascularization.

Coronary revascularization in diabetic patients: a comparison of the randomized and observational components of the Aypass Angioplasty Revascularization Investigation (BARI)

BACKGROUND

Patients with treated diabetes in the randomized-trial segment of the Bypass Angioplasty Revascularization Investigation (BARI) who were randomized to initial revascularization with PTCA had significantly worse 5-year survival than patients assigned to CABG. This treatment difference was not seen among diabetic patients eligible for BARI who opted to select their mode of revascularization. We hypothesized that differences in patient characteristics, assessed and unmeasured, together with the treatment selection in the registry, at least partially account for this discrepancy.

METHODS AND RESULTS

Among diabetics taking insulin or oral hypoglycemic drugs at entry, angiographic and clinical presentations were comparable between randomized and registry patients. However, more registry patients were white, and registry diabetics tended to be more educated and more physically active and to report better quality of life. Procedural characteristics and in-hospital complications were comparable. The 5-year all-cause mortality rate was 34.5% in randomized diabetic patients assigned to PTCA versus 19.4% in CABG patients (P=0.0024; relative risk [RR]=1.87); corresponding cardiac mortality rates were 23.4% and 8.2%, respectively (P=0.0002; RR=3.10). The CABG benefit was more apparent among patients requiring insulin. In the registry, all-cause mortality was 14.4% for PTCA versus 14.9% for CABG (P=0.86, RR=1.10), with corresponding cardiac mortality rates of 7.5% and 6. 0%, respectively (P=0.73; RR=1.07). These RRs in the registry increased to 1.29 and 1.41, respectively, after adjustment for all known differences between treatment groups.

CONCLUSIONS

BARI registry results are not inconsistent with the finding in the randomized trial that initial CABG is associated with better long-term survival than PTCA in treated diabetic patients with multivessel coronary disease suitable for either surgical or catheter-based revascularization.

Effect of age in the Bypass Angioplasty Revascularization Investigation (BARI) randomized trial

BACKGROUND

The influence of age on the relative success of either percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG) in patients requiring myocardial revascularization continues to be controversial.

METHODS

In the Bypass Angioplasty Revascularization Investigation (BARI) trial, 1,829 patients with symptomatic multivessel coronary artery disease requiring revascularization were randomly assigned to undergo either CABG or PTCA.

RESULTS

Seven hundred nine patients (39%) were 65 to 80 years old at baseline; the other 1,120 were younger than 65 years. The in-hospital 30-day mortality rate for PTCA and CABG in the younger patients was 0.7% and 1.1%, respectively, and that for patients 65 years or older was 1.7% and 1.7%, respectively. In older compared with younger patients, stroke was more common after CABG (1.7% versus 0.2%, p = 0.015) and heart failure or pulmonary edema was more common after PTCA (4.0 versus 1.3%, p = 0.011). In both age groups, CABG resulted in greater relief of angina and fewer repeat procedures. The 5-year survival rate in patients younger than 65 years was 91.5% for CABG and 89.5% for PTCA. In patients 65 years or older, the 5-year survival rate was 85.7% for CABG and 81.4% for PTCA. Cardiac mortality at 5 years was greater in patients assigned to the PTCA group than in those assigned to the CABG group. However, no significant treatment differences were noted in cardiac mortality when only nondiabetic patients were examined.

CONCLUSIONS

Within the context of the Bypass Angioplasty Revascularization Investigation trial, older patients with multivessel coronary disease do well with either PTCA or CABG. Compared with younger patients, older patients had less recurrent angina and were less likely to undergo repeat procedures, particularly among those assigned to undergo CABG. Cardiac mortality was greater in patients 65 years or older assigned to undergo PTCA; however, this difference was not noted when treated diabetic patients were excluded from analysis.

Employment after coronary angioplasty or coronary bypass surgery in patients employed at the time of revascularization

BACKGROUND

Patients who undergo coronary angioplasty have a shorter convalescence than those who undergo coronary bypass surgery. This may improve subsequent employment.

OBJECTIVE

To compare employment patterns after coronary angioplasty or surgery.

DESIGN

Multicenter, randomized clinical trial.

SETTING

Seven tertiary care hospitals.

PATIENTS

409 employed patients with multivessel coronary artery disease.

INTERVENTION

Coronary bypass surgery or balloon angioplasty.

MEASUREMENTS

Time to return to work and time spent working during 4 years of follow-up.

RESULTS

Patients who underwent angioplasty returned to work 6 weeks sooner than patients who underwent coronary bypass surgery (P < 0.001), but long-term employment did not differ significantly (P > 0.2). Long-term employment was significantly lower among patients who were 60 to 64 years of age (P < 0.001), those who worked less than full-time at study entry (P < 0.001), and those who had less formal education (P = 0.005). Patients with only one source of health insurance were more likely to continue working (P = 0.005).

CONCLUSIONS

Faster recovery after angioplasty speeds return to work but does not improve long-term employment, which is primarily associated with nonmedical factors.

Quality of life at baseline: is assessment after randomization valid? The AVID Investigators. The Antiarrhythmics Versus Implantable Defibrillators

OBJECTIVES

The purpose of this report is to examine whether differences existed between patients who completed a baseline quality of life (QoL) form before being informed about their randomized assignments versus those who completed it after knowing their randomization assignments.

METHODS

In the pilot phase of the Antiarrhythmics Versus Implantable Defibrillators (AVID) study (n = 200), 113 patients completed a baseline QoL battery prior to randomization (drug versus defibrillator), 49 additional patients completed this battery after randomization, and 38 patients did not complete this battery. Baseline demographic, clinical and QoL data were compared for these groups.

RESULTS

Although the two groups with QoL data were not significantly different regarding various clinical and demographic characteristics, they did have significantly different QoL profiles. Patients with QoL collected before randomization had better overall QoL scores and mental health scores.

CONCLUSIONS

These data suggest that patients with worse QoL may be less willing to complete a baseline QoL form in a timely manner or that knowledge of the randomization assignment may have an effect on QoL.

Better outcome for women compared with men undergoing coronary revascularization: a report from the bypass angioplasty revascularization investigation (BARI)

BACKGROUND

Numerous studies have shown that women undergoing coronary revascularization procedures do so at a higher risk for an adverse outcome compared with men. However, the impact of advances in technology and improvements in techniques on in-hospital and long-term outcome after revascularization in women is unclear.

METHODS AND RESULTS

We evaluated 1829 patients with symptomatic multivessel coronary disease randomized to CABG or PTCA in the Bypass Angioplasty Revascularization Investigation (BARI), of whom 27% were women. As expected, women were older (64.0 versus 60.5 years), with more congestive heart failure (14% versus 7%), hypertension (68% versus 42%), treated diabetes mellitus (31% versus 15%), and unstable angina (67% versus 61%) than men but had similar preservation of left ventricular function and extent of multivessel disease. Women assigned to surgery received the same number of total grafts but fewer internal mammary artery grafts (72% versus 85%, P<0. 01), and those assigned to angioplasty had more intended lesions (76% versus 71%, P<0.01) successfully dilated than men. At an average of 5.4 years' follow-up, crude mortality rates were similar in women (12.8%) and men (12.0%). The Cox regression model adjusting for baseline differences revealed that women had a significantly lower risk of death (relative risk, 0.60; 95% CI, 0.43 to 0.84; P=0. 003) but not a significantly lower risk of death plus myocardial infarction (relative risk, 0.84; 95% CI, 0.66 to 1.07; P=0.16) than men.

CONCLUSIONS

Although the unadjusted mortality rate suggests that women and men undergoing CABG and PTCA have a similar 5-year mortality, women have higher risk profiles; consequently, contrary to previous reports, female sex is an independent predictor of improved 5-year survival after we control for multiple risk factors.

Long-term prognostic value of clinically evident noncoronary vascular disease in patients undergoing coronary revascularization in the Bypass Angioplasty Revascularization Investigation (BARI)

In the general population, peripheral atherosclerosis is a strong predictor of cardiovascular disease and death. In patients with known coronary artery disease, it is unclear whether the presence of additional noncoronary atherosclerosis is of further prognostic value. In the Bypass Angioplasty Revascularization Investigation, 5-year outcome was compared between patients with and without clinically evident noncoronary atherosclerosis. Within the subgroup with noncoronary atherosclerosis, surgery, and angioplasty treatment strategies were compared. Noncoronary atherosclerosis was defined as claudication, peripheral vascular surgery, abdominal aortic aneurysm, history of cerebral ischemia, or carotid disease. Among 1,816 patients, 303 (17%) had noncoronary atherosclerosis. These patients were more likely to have a history of congestive heart failure, diabetes, and hypertension, and were more likely to smoke. Coronary angiographic variables were similar between the 2 groups. Five-year survival was 75.8% for patients with noncoronary atherosclerosis and 90.2% for those without (p < 0.001). The adjusted relative risk of death was 1.7 for any noncoronary atherosclerosis, 1.5 for lower extremity disease alone, 1.7 for cerebral disease alone, and 2.3 for both conditions. Among the 303 patients with noncoronary atherosclerosis, the adjusted relative risk of death for surgery versus angioplasty was 0.87 (p = 0.40). However, the study has limited power to detect a treatment effect in this small subgroup. Thus, patients with combined coronary and clinically evident noncoronary atherosclerosis are a high-risk group with significantly worse long-term outcome compared patients with isolated coronary disease.

Cognitive function 5 years after randomization to coronary angioplasty or coronary artery bypass graft surgery

BACKGROUND

Coronary bypass surgery often leads to short-term cognitive dysfunction, whereas coronary angioplasty does not. Perioperative cognitive dysfunction usually resolves, although a subgroup of surgical patients may continue to exhibit long-term cognitive dysfunction. The purpose of this study was to compare cognitive function 5 years after randomization to a strategy of either initial coronary surgery or initial angioplasty.

METHODS AND RESULTS

Five centers in the Bypass Angioplasty Revascularization Investigation participated in this ancillary study. Patients with multivessel coronary disease randomized to angioplasty or surgery were eligible at the time of their 5-year clinic visit. A battery of five measures previously shown to be sensitive to perioperative changes in cognitive function was administered, including the Logical and Figural Memory Scales from the Wechsler Memory Scale, the Digit Symbol and Digit Span subtests from the Wechsler Adult Intelligence Scale, and Part B of the Reitan Trail Making Test. The 125 study patients were generally similar to the 133 patients who were eligible but did not participate, although study participants were significantly younger (P=.003). The 64 patients randomly assigned to angioplasty had baseline characteristics similar to those of 61 patients randomly assigned to surgery. Cognitive function scores were not significantly different between angioplasty or surgery patients in an intention-to-treat analysis (P=.57). There also was no difference in cognitive function scores when the data were analyzed according to whether the patient had ever undergone bypass surgery (P=.59).

CONCLUSIONS

Long-term cognitive function is similar after coronary bypass surgery and coronary angioplasty in the majority of patients.

Gender differences in health-related quality of life among postmyocardial infarction patients: brief report. CAST Investigators. Cardiac Arrhythmia Suppression Trials

Heart disease is the leading cause of death among women in the United States. The prognosis for heart disease is worse for women than for men. Also, although women are less likely than men to initially present with a myocardial infarction (MI), they are more likely to die following an MI. A number of factors have been identified that partially account for the gender difference in post-MI morbidity and mortality. However, limited data are available on the sex differences in clinical, psychosocial, and demographic factors that may combine to explain the poorer prognosis for women following an acute MI. The Cardiac Arrhythmia Suppression Trials collected detailed demographic, clinical, and psychosocial data on 2,043 men and 448 women following acute MIs. Analyses indicate that women had a worse clinical, socioeconomic, and psychosocial profile than did men. In addition, significant differences in psychosocial profiles persisted after controlling for demographic and clinical data, suggesting that women presenting with MIs have a cluster of complex factors that put them at high risk for morbidity and mortality following an MI. Future longitudinal studies that include adequate numbers of women as well as reliable assessments of both clinical and psychological variables are needed to better understand the factors that influence the poor prognosis for women with coronary heart disease.

The substrate specificity of the enzyme endo-alpha-N-acetyl-D-galactosaminidase from Diplococcus pneumonia

The substrate specificity of the enzyme endo-alpha-N-acetyl-D-galactosaminidase from Diplococcus pneumonia was re-examined using bovine submaxillary mucin and remodelled antifreeze glycoprotein as substrates. Incubation with desialylated bovine submaxillary mucin, which contains six O-linked core types, indicated that the disaccharide Gal beta1-3GalNAc, which is present in very small amount, was the only glycan released, while the disaccharide GlcNAc beta1-3GalNAc, which is the major structure present, and other disaccharides, were not released. To test whether the core disaccharide Gal beta1-3GalNAc with sialic acid linked alpha2-3 to the Gal or linked alpha2-6 to the GalNAc was released, the enzyme was incubated with remodelled antifreeze glycoprotein containing (1) [3H]NeuAc alpha2-3Gal beta1-3GalNAc and (2) Gal beta1-3[[14C]NeuAc alpha2-6]GalNAc as substrates. No NeuAc-containing trisaccharide was released. These results serve to clarify the doubts of many researchers regarding the activity of this enzyme on some newly-described core types and on sialylated substrates.

Medical care costs and quality of life after randomization to coronary angioplasty or coronary bypass surgery. Bypass Angioplasty Revascularization Investigation (BARI) Investigators

BACKGROUND

Randomized trials comparing coronary angioplasty with bypass surgery in patients with multivessel coronary disease have shown no significant differences in overall rates of death and myocardial infarction. We compared quality of life, employment, and medical care costs during five years of follow-up among patients treated with angioplasty or bypass surgery.

METHODS

A total of 934 of the 1829 patients enrolled in the randomized Bypass Angioplasty Revascularization Investigation participated in this study. Detailed data on quality of life were collected annually, and economic data were collected quarterly.

RESULTS

During the first three years of follow-up, functional-status scores on the Duke Activity Status Index, which measures the ability to perform common activities of daily living, improved more in patients assigned to surgery than in those assigned to angioplasty (P<0.05). Other measures of quality of life improved equally in both groups throughout the follow-up period. Patients in the angioplasty group returned to work five weeks sooner than did patients in the surgery group (P<0.001). The initial mean cost of angioplasty was 65 percent that of surgery ($21,113 vs. $32,347, P<0.001), but after five years the total medical cost of angioplasty was 95 percent that of surgery ($56,225 vs. $58,889), a difference of $2,664 (P = 0.047). The five-year cost of angioplasty was significantly lower than that of surgery among patients with two-vessel disease ($52,930 vs. $58,498, P<0.05), but not among patients with three-vessel disease ($60,918 vs. $59,430). After five years of follow-up, surgery had an overall cost-effectiveness ratio of $26,117 per year of life added, but unacceptable ratios of $100,000 or more per year of life added could not be excluded (P=0.13). Surgery appeared particularly cost effective in treating diabetic patients because of their significantly improved survival.

CONCLUSIONS

In patients with multivessel coronary disease, coronary-artery bypass surgery is associated with a better quality of life for three years than coronary angioplasty, after the initial morbidity caused by the procedure. Coronary angioplasty has a lower five-year cost than bypass surgery only in patients with two-vessel coronary disease.

Chronobiology of acute myocardial infarction: cardiac arrhythmia suppression trial (CAST) experience

The onset of acute myocardial infarction (AMI) has been shown to occur in a reproducible pattern with a peak in mid-morning and a secondary peak in late afternoon and early evening. More detailed information on the timing of this catastrophic event may provide important pathophysiologic information. Using the database from the Holter Registry of the Cardiac Arrhythmia Suppression Trial (CAST) (n = 22,516), the day of the week, the month, and season of the onset of AMI was obtained and correlated with demographic characteristics. The pattern of the day of onset for the entire population was significantly nonuniform (p <0.0001) with a Monday peak and a weekend nadir. This pattern was observed in most of the examined subgroups. Analysis of seasonal data revealed nonuniform distribution (p <0.001) with a peak in winter and autumn. We conclude that AMI is not a random event but occurs in definite patterns related to the day of the week and the season of the year. These patterns were observed in a wide variety of patient subgroups and appear related to climate, occupation, and other factors.

Logrank, play the winner, power and ethics

We show by simulation and numerical integration techniques that power is largely unaffected by play the winner strategies in a typical chronic disease mortality trial utilizing the logrank test. This raises the issue of the ethics of equal allocation in such a setting.

Adherence and arrhythmic mortality in the cardiac arrhythmia suppression trial (CAST)

Patient adherence to therapy is essential to assess treatment efficacy, particularly in clinical trials. Active treatment usually is expected to benefit patients. The healthy adherer effect, the association or greater adherence to all health-promoting behaviors, including medication and overall concern for health, explains the improved survival of more adherent patients in both active and placebo medication groups of several clinical trials. The Cardiac Arrhythmia Suppression Trial (CAST), a placebo-controlled double-blind clinical trial of post-myocardial infarction (MI) patients with asymptomatic ventricular arrhythmias, in which active medication (encainide or flecainide) led to increased mortality, provided an opportunity to examine the relationship of adherence to survival from a different perspective. We consider whether adherence to active treatment was related to arrhythmic mortality and whether a healthy adherer effect might counteract the effect of treatment on mortality among patients taking active medication. Adherence (average pill count) at the first follow-up visit did not differ in the active treatment (92.2%, standard deviation (SD) = 11.97, n = 574) and placebo (90.8%, SD = 13.66, n = 579) groups. In a Cox proportional hazard regression model, medication adherence predicted arrhythmic mortality among the active (P < 0.0062) but not the placebo medication group. The effect of adherence on arrhythmic mortality was significant beyond the effects of ejection fraction, race, spouse, smoking status, diuretic medication, and history of MI. A 10% increase in adherence led to more than a threefold increase of risk of arrhythmic death. The design of the CAST, which included a titration phase, may have tended to select relatively adherent patients since only those whose arrhythmias were suppressed with active medication were randomized into the trial. The data do not support a strong healthy adherer effect in the CAST. There was no evidence in this study that a healthy adherer effect counterbalanced the effect of the active medication.

Relation of sociodemographic, clinical, and quality-of-life variables to adherence in the cardiac arrhythmia suppression trial

Clearly, age and education are important factors for predicting adherence in CAST, given that they appear in all three regressions. Moreover, the 4-month and 1-year results indicate that mental health and presence of a spouse are important predictors. Physical function, stress, angina, and history of MI may also provide additional information regarding adherence levels. It is interesting to note that although adherence was higher for patients who have "good" social characteristics, such as having a spouse, support, integration, perceived good health, good mental health, low stress, and education, it was also better for those patients who had "poor" physical characteristics such as a history of angina, a history of MI, and low physical function. In the multivariate analysis, older age was also associated with good adherence. These observations are not necessarily intuitive and support the need for further research in this area. If patients at risk for poor adherence can be identified prospectively, strategies may be developed to improve their subsequent medical care in such a way to favorably affect and improve their outcomes.

Smoking cessation and arrhythmic death: the CAST experience. The Cardiac Arrhythmia Suppression Trial (CAST) Investigators

OBJECTIVES

This study was performed to assess the effect of cigarette smoking cessation on overall mortality and the incidence of arrhythmic death in the population of the Cardiac Arrhythmia Suppression Trial (CAST).

BACKGROUND

Cigarette smoking is a known risk factor for sudden cardiac death. Some of the adverse effects of smoking have been shown to dissipate with smoking cessation, but the time frame over which these changes occur and the population that stands to benefit have not been well delineated. CAST was a multicenter double-blind placebo-controlled study to determine whether suppression of ventricular ectopic activity by means of antiarrhythmic drugs in patients with left ventricular dysfunction after acute myocardial infarction would reduce the incidence of arrhythmic death.

METHODS

Of 2,752 patients randomized to blinded therapy, 1,026 were smoking at the time of their baseline examination and completed a 4-month follow-up visit. Of these, 517 stopped smoking by the time of this visit ("quitters") and 509 continued to smoke ("smokers").

RESULTS

Over a mean follow-up period of slightly < 16 months, there were 17 arrhythmic deaths and 32 total deaths among the quitters versus 30 and 45, respectively, among the smokers; these differences were of marginal statistical significance. Most of the fatal events occurred in a group at high risk of ongoing ischemia: the 558 patients who did not have thrombolysis or undergo revascularization after their qualifying myocardial infarction. In this high risk cohort, smoking cessation greatly reduced the incidence of arrhythmic death and was associated with a statistically significant benefit in survival.

CONCLUSIONS

Smoking cessation was accompanied by a marked reduction in arrhythmic death and overall mortality that achieved statistical significance in a high risk cohort. These data imply that smoking cessation is important in risk factor reduction in patients with advanced ischemic heart disease.

A simulation study used to design the sequential monitoring plan for a clinical trial

In designing a sequential monitoring plan for the AVID (Antiarrhythmics Versus Implantable Defibrillators) study, a multi-centred clinical trial, we completed a simulation study to help ourselves and the Data Safety Monitoring Board understand the implications of various monitoring plans. In particular, we compared three test statistics and three use functions. Simulation was based on approximate trial parameters and two plausible but distinct alternative hypotheses. The power to detect a difference between the two treatment arms was computed as a function of time. The simulated results illuminate several of the important statistical and ethical issues involved in selecting a sequential monitoring plan and illustrate how one can use simulations to design a clinical trial.

Effect of age on postmyocardial infarction ventricular arrhythmias (Holter Registry data from CAST I and CAST II). Cardiovascular Arrhythmia Suppression Trials

Holter data from the 17,609 postmyocardial infarction patients in the CAST Registry were analyzed to study the effect of age on VPC and VT incidence and frequency. Multivariable analysis demonstrated that age is an important independent predictor of increased ventricular ectopy, with the median rate of VPCs/hour increasing from 0.4 (patients aged < 50 years) to 4.0 (patients aged 75 to 80 years), and the prevalence of VT increasing from 7.3% (patients aged < 50 years) to 15.3% (patients aged 75 to 80 years).

Association between ease of suppression of ventricular arrhythmia and survival

BACKGROUND

We tested the hypothesis that patients whose ventricular arrhythmias are easy to suppress have a lower rate of arrhythmic death, defined as arrhythmic death and nonfatal cardiac arrest, the primary end point in the Cardiac Arrhythmia Suppression Trials (CAST-I and CAST-II), than patients whose ventricular arrhythmias are hard to suppress. In addition, we evaluated the association between ease of suppression of ventricular arrhythmias and mortality of all causes.

METHODS AND RESULTS

CAST-I investigated the effect on arrhythmic death of ventricular premature depolarization (VPD) suppression achieved by three drugs, encainide, flecainide, and moricizine, at two different dose levels; CAST-II investigated the same effect, using moricizine alone at three dose levels. If suppression was achieved, patients were randomized to the effective active drug or corresponding placebo. To examine the independence of easily suppressed ventricular arrhythmias as a predictor of arrhythmic death, we adjusted statistically for other variables that were related both to ease of suppression and arrhythmic death. Patients with ventricular arrhythmias (n = 1778) that were easy to suppress had fewer arrhythmic deaths during follow-up than those with ventricular arrhythmias that were hard to suppress (n = 1173) (relative risk, .59; P = .003). Patients whose VPDs were easily suppressed were older and had a lower frequency of prior history of heart failure and myocardial infarction. They also had a higher incidence of anterior myocardial infarction, VPD frequency, and average ejection fraction. After adjusting for these variables, we found that easily suppressed ventricular arrhythmias were still significant predictors of arrhythmic death (relative risk, .66; P = .013).

CONCLUSIONS

This study shows that the ease of VPD suppression identifies a subgroup of postmyocardial infarction patients who have low risk of arrhythmic death.

Moricizine and quality of life in the Cardiac Arrhythmia Suppression Trial II (CAST II)

The Cardiac Arrhythmia Suppression Trial II (CAST II) was a double-masked placebo-controlled randomized trial that compared the survival effects of moricizine to placebo in postmyocardial infarction arrhythmia patients. The quality-of-life outcome measures were designed prospectively for CAST and were previously shown to have high reliability and clinical discriminative validity. The CAST quality-of-life instrument detected significant differences between moricizine and placebo. In particular, moricizine was most strongly associated with inferior social activity and satisfaction scores (p = .014) and lower scores for overall contentment with life (p = .007). Moreover, the quality-of-life measures improved significantly for both the moricizine and placebo treatment groups after entry into the clinical trial. These results indicate that the CAST quality-of-life instrument is sensitive for assessing pharmacological therapies in the treatment of heart disease.

Beta-blocker therapy in the Cardiac Arrhythmia Suppression Trial. CAST Investigators

The Cardiac Arrhythmia Suppression Trial (CAST) showed antiarrhythmic drug suppression of asymptomatic or mildly symptomatic ventricular arrhythmias in survivors of myocardial infarction to be harmful. This study retrospectively searched the CAST results for evidence of mortality and morbidity reduction in patients receiving optional beta-blocker therapy. All enrolled (n = 2,611) and suppressed main study (n = 1,735) CAST patients with an ejection fraction of < or = 40% were examined using univariate analysis, Kaplan-Meier curves, and a Cox proportional-hazards multivariate analysis with respect to optional beta-blocker therapy prescribed at baseline. CAST patients receiving beta-blocker therapy had significantly enhanced survival at 30 days, and at 1 and 2 years of follow-up against all-cause and arrhythmic death or nonfatal cardiac arrest. Multivariate analysis showed beta-blocker therapy to be independently associated with a one-third reduction in arrhythmic death or cardiac arrest (p = 0.036). In CAST patients with a history of congestive heart failure, beta-blocker therapy was independently associated with longer time to occurrence of new or worsened congestive heart failure (p = 0.015). This study supports the secondary preventive benefit of beta-blocker therapy in high-risk post-myocardial infarction patients, and calls attention to the possible preventive benefit of beta-blocker therapy against proarrhythmic events experienced in the CAST.

Prognostic significance of left ventricular aneurysm in the Cardiac Arrhythmia Suppression Trial (CAST) population

Left ventricular aneurysm has been associated with increased mortality rates. The Cardiac Arrhythmia Suppression Trial (CAST) database was used prospectively to assess (1) the prognostic significance of left ventricular (LV) aneurysm after myocardial infarction on mortality rates and (2) the relation of LV aneurysm to ventricular arrhythmias and their suppressibility. All patients in the CAST study were enrolled after myocardial infarction. They had > or = 6 ventricular premature depolarizations (VPDs) per hour and ejection fraction < or = 55%; they were enrolled in the study an average of 96 days after the index myocardial infarction. Of 2494 patients with wall motion data, 164 had LV aneurysm, 600 had only dyskinesis, 913 had only akinesis, and 817 had none of these. Radionuclide scan was used in 39%, two-dimensional echocardiography in 30%, and LV angiogram in 31%. Baseline VPDs and nonsustained ventricular tachycardia were similar in all groups. LV aneurysm patients were more frequently eliminated during open-label titration. The incidence of sustained VT during follow-up was only 2.8% for aneurysm patients, a rate that was similar to the other groups. Patients with LV aneurysm had significantly lower survival rates (82% vs 91%) at 16 months after study entry than those without these wall motion abnormalities (p < 0.005). When survival rates were adjusted for ejection fraction there was still a moderately large hazard ratio (1.34) of LV aneurysm that was not statistically significant (p = 0.18). We conclude that (1) the presence of LV aneurysm does not independently worsen prognosis, and (2) older concepts of LV aneurysm and ventricular arrhythmias must be reevaluated.

Circadian pattern of arrhythmic death in patients receiving encainide, flecainide or moricizine in the Cardiac Arrhythmia Suppression Trial (CAST)

OBJECTIVES

The purpose of this study was to assess the effect of antiarrhythmic drugs on the timing of arrhythmic death.

BACKGROUND

Sudden cardiac death remains a problem of epidemic proportions. Delineating its pathophysiology is an important step in devising preventive measures. Previous studies have shown a circadian pattern of onset of sudden cardiac death. The effect of antiarrhythmic drugs on this pattern has not been systematically studied.

METHODS

The Cardiac Arrhythmia Suppression Trial (CAST) was a multicenter double-blind, placebo-controlled study designed to determine whether suppression of ventricular ectopic activity by means of antiarrhythmic drugs (encainide, flecainide or moricizine) after acute myocardial infarction would reduce the incidence of arrhythmic death.

RESULTS

The trial was terminated prematurely because of an unexpectedly high mortality rate in the active treatment group. The onset of arrhythmic death in this group (in patients not receiving beta-adrenergic blocking agents) displayed a bimodal variation, with significant peaks in midmorning and late afternoon/early evening. More than half of the symptomatic events were accompanied by anginalike symptoms. Approximately 30% of all events occurred within 2 h of awakening.

CONCLUSIONS

Our data suggest the possibility of a complex interaction among antiarrhythmic drugs, sympathetic nervous system activation and acute myocardial ischemia. Planning of future antiarrhythmic drug trials will need to take this information into account.

Identification of a secondary peak in myocardial infarction onset 11 to 12 hours after awakening: the Cardiac Arrhythmia Suppression Trial (CAST) experience

OBJECTIVES

The purpose of this study was to assess the relation between the time of awakening and the time of onset of acute myocardial infarction.

BACKGROUND

Previous investigation has shown the onset of symptoms of acute myocardial infarction to have a primary peak 1 to 2 h after awakening. In studies not corrected for time of awakening, there appears to be a late afternoon/early evening peak, but data correlating the onset of symptoms with awakening have been limited by small numbers of patients, perhaps precluding identification of a secondary peak.

METHODS

In the Cardiac Arrhythmia Suppression Trial (CAST), 3,549 patients had a documented myocardial infarction and entered antiarrhythmic drug titration. Of these, 3,309 had data on the onset of symptoms relative to the time of awakening and form the basis of this report.

RESULTS

A total of 870 patients (26.3%) were awakened by symptoms. Of the remaining 2,439 patients who were not awakened by symptoms, 798 (32.7%) experienced the onset of symptoms in the 1st 4 h after awakening (with the highest number in the 1st h), after which the incidence of symptom onset decreased in a linear fashion, with a secondary peak 11 to 12 h after awakening. Both peaks are statistically significant. A similar pattern was seen in most of the subgroups examined (based on age, gender and various other demographic characteristics).

CONCLUSIONS

Analysis of the very large CAST data base confirms the relation between awakening and onset of symptoms of myocardial infarction, suggesting involvement of the morning catecholamine surge. A secondary peak in symptom onset, occurring 11 to 12 h after awakening, is a new observation and may relate to ingestion of the evening meal or other trigger factors concentrated in those hours.

Psychosocial predictors of mortality in the Cardiac Arrhythmia Suppression Trial-1 (CAST-1)

Psychosocial variables predict the recurrence of clinical events in symptomatic patients, controlling for measures of disease severity. The Cardiac Arrhythmia Suppression Trial-1, a pharmacologic test of the arrhythmia suppression and mortality hypothesis among postmyocardial infarction patients, allowed a prospective test of the relationship of distress, perceived support, social interaction, life stress, and other variables, to mortality, adjusting statistically for ejection fraction, arrhythmia rates, and other known risk factors for coronary heart disease. Results indicated that the treatment medications, encainide and flecainide, were powerful predictors of mortality. Although the psychosocial variables were significant as univariate predictors, these variables were not significant as predictors in a multivariate model that included drug treatment. When the data analysis was restricted to patients randomized to placebo, thereby eliminating the antiarrhythmic drug effect, the level of perceived social support was a significant multivariate predictor of mortality, adjusting for measures of disease severity. The adjusted hazards ratio for a 1-point decrease in the perceived support score is equal to 1.46, based on the multivariate model.

The stereochemical course of reactions catalysed by the cellobiohydrolases produced by Talaromyces emersonii

Three forms of exocellobiohydrolase (EC 3.2.1.91), CBH IA, CBH IB and CBH II, were isolated to apparent homogeneity from culture filtrates of the aerobic fungus Talaromyces emersonii. CBH IA and CBH II appear to be native forms of these enzymes, while CBH IB may represent a proteolytic degradation product of the CBH IA enzyme. The hydrolysis of beta-cellobiosyl fluoride by each form was monitored by 1H-n.m.r. spectroscopy. The reactions catalysed by CBH IA and CBH IB proceed with retention of the anomeric configuration, whereas that catalysed by CBH II is one of inversion. Thus one may deduce that CBH IA (or CBH IB) and CBH II operate double and single displacement reactions respectively during catalysis of substrate. On the basis of these findings and the observed substrate specificities of the various forms, one may conclude that CBH IA (and CBH IB) is a family C enzyme, while CBH II belongs to family B [Henrissat, Claeyssens, Tomme, Lemesle & Mornon (1989) Gene 81, 83-95].

Artifactual elevation of thyroid-stimulating hormone

A clinically euthyroid patient was found to have a normal serum thyroxine level and an elevated plasma thyrotropin (TSH) level measured by fluoroimmunoassay. Thyroid hormone therapy failed to suppress the TSH level. The TSH level was unresponsive to thyrotropin-releasing hormone (TRH) administration, alpha-subunits of pituitary glycoproteins were undetectable in her plasma, and imaging of the pituitary-hypothalamic region was normal. Measurement of TSH with an assay containing sheep antibody to TSH failed to reveal TSH in the patient's plasma. Addition of mouse IgG to the TSH fluoroimmunoassay reduced the patient's TSH to an undetectable level. These observations are consistent with a spurious elevation of TSH due to the presence of an anti-mouse antibody. Artifactual elevations of TSH have not been identified commonly, but this possibility should be considered when the TSH level is inappropriate for the apparent state of thyroid function.