Incidence and mortality risk of congestive heart failure in atrial fibrillation patients: a community-based study over two decades

AIMS

We sought to determine whether the incidence of and survival following congestive heart failure (CHF) in patients with atrial fibrillation (AF) have changed over time.

METHODS AND RESULTS

Olmsted County, Minnesota residents diagnosed with first AF during 1980-2000 were identified and followed in medical records to 2004. The trends of incidence and survival of CHF over time were assessed. Of the 3288 subjects (mean age 71+/-15 years) diagnosed with first AF and without CHF prior to or at AF diagnosis, 790 (24%) developed a first CHF during a mean follow-up of 6.1+/-5.2 years (unadjusted incidence, 44 per 1000 person years). Age- and sex-adjusted CHF incidence was unrelated to calendar year of AF diagnosis (P = 0.86). The age- and sex-adjusted mortality risk following CHF was higher than that in patients without CHF (hazard ratio 3.4, 95% confidence interval 3.1-3.8, P < 0.0001). There were no detectable changes over time with respect to the absolute (P = 0.94) or the relative (P = 0.68) mortality risk after CHF diagnosis.

CONCLUSION

In this study spanning two decades, there appeared to have been no significant reduction in terms of the incidence and mortality risk of CHF following first AF diagnosis.

An Echocardiographic Left Ventricular Wall Area Index for Functional Detection of Myocardial Injury in Hemodynamically Unloaded Hearts

Functional assessment of the left ventricle is affected by loading conditions. Detection of rejection-mediated myocardial injury in a heterotopic heart transplant model is a challenge for the echocardiographer because the heart is in an unloaded state. We examined the relationship of a novel left ventricular (LV) wall area index (LVWAI) and serum cardiac troponin T (cTnT) levels. The LVWAI, based on prior methods of determining LV mass, was defined as the difference between epicardial and endocardial areas divided by the epicardial area. The biphasic morphometric response of LVWAI reflected changes in the cTnT levels and allowed echocardiographic detection of myocardial injury in hemodynamically unloaded hearts.

Relative risk of mortality associated with diabetes as a function of birth weight

OBJECTIVE

Birth weight is a risk factor for both diabetes and mortality. Diabetes is a risk factor for mortality. Whether the excess mortality observed for diabetes varies with birth weight is unclear.

RESEARCH DESIGN AND METHODS

Among all 2,508 Rochester, Minnesota, residents who first met research criteria for adult-onset diabetes in 1960-1995, 171 were born locally in-hospital after 1922 (i.e., birth weights available) as singleton, term infants. Each case subject and two age- and sex-matched nondiabetic control subjects (born locally, residing locally when the case subject met the criteria for diabetes) were followed through 31 December 2000 for vital status.

RESULTS

Of the diabetic case subjects, 16% (27 of 171) died vs. 7% (25 of 342) of control subjects (P = 0.004). The difference was less for normal-birth-weight (NBW) (2,948-<3,856 g) individuals (12% [12 of 102] vs. 8% [20 of 246], P = 0.31) than for abnormal-birth-weight individuals (low birth weight [LBW] 20% [8 of 39] vs. 2% [1 of 46], P = 0.01; high birth weight [HBW] 23% [7 of 30] vs. 8% [4 of 50], P = 0.16), as confirmed with age- and sex-adjusted Cox proportional hazards (diabetes-associated hazard ratio 1.4 [95% CI 0.69-2.90] for NBW vs. 4.8 [1.7-13.3] for abnormal birth weight, test for interaction P = 0.056). The observed diabetes deaths were greater than expected, based on mortality for the general population (27 vs. 13.3, P < 0.001), with 70% of excess deaths occurring among LBW (8 vs. 2.2, P < 0.001) and HBW (7 vs. 3.1, P = 0.03) individuals.

CONCLUSIONS

The excess mortality observed for diabetes appears disproportionately concentrated among abnormal-birth-weight individuals, thus identifying a subset of at-risk diabetic individuals and reinforcing the importance of NBW deliveries.

Trends in the incidence of venous thromboembolism during pregnancy or postpartum: a 30-year population-based study

BACKGROUND

The risk for venous thromboembolism during pregnancy or postpartum is uncertain.

OBJECTIVES

To estimate the relative and absolute risk for deep venous thrombosis and pulmonary embolism during pregnancy and postpartum and to describe trends in incidence.

DESIGN

Population-based inception cohort study using the resources of the Rochester Epidemiology Project.

SETTING

Olmsted County, Minnesota.

PATIENTS

Women with deep venous thrombosis or pulmonary embolism first diagnosed between 1966 and 1995, including women with venous thromboembolism during pregnancy or the postpartum period (defined as delivery of a newborn no more than 3 months before the deep venous thrombosis or pulmonary embolism event date, including delivery of a stillborn infant after the first trimester).

MEASUREMENTS

The authors obtained yearly counts of live births in Olmsted County between 1966 and 1995 from the Minnesota Department of Health.

RESULTS

The relative risk (standardized incidence ratio) for venous thromboembolism among pregnant or postpartum women was 4.29 (95% CI, 3.49 to 5.22;P < 0.001), and the overall incidence of venous thromboembolism (absolute risk) was 199.7 per 100,000 woman-years. The annual incidence was 5 times higher among postpartum women than pregnant women (511.2 vs. 95.8 per 100,000), and the incidence of deep venous thrombosis was 3 times higher than that of pulmonary embolism (151.8 vs. 47.9 per 100,000). Pulmonary embolism was relatively uncommon during pregnancy versus the postpartum period (10.6 vs. 159.7 per 100,000). Over the 30-year study period, the incidence of venous thromboembolism during pregnancy remained relatively constant whereas the postpartum incidence of pulmonary embolism decreased more than 2-fold.

LIMITATIONS

Because the Olmsted County population was 98% white and of non-Hispanic ethnicity, the results may not be generalizable to other ethnicities.

CONCLUSIONS

Among pregnant women, the highest risk period for venous thromboembolism and pulmonary embolism in particular is during the postpartum period. Any prophylaxis against these events should be particularly targeted to postpartum women. Although the incidence of pulmonary embolism has decreased over time, the incidence of deep venous thrombosis remains unchanged, indicating the need to better identify pregnant women at increased risk.

Role of endothelial NO synthase phosphorylation in cerebrovascular protective effect of recombinant erythropoietin during subarachnoid hemorrhage-induced cerebral vasospasm

BACKGROUND AND PURPOSE

In the present study, the effect of subarachnoid hemorrhage (SAH) on the phosphorylation of endothelial NO synthase (eNOS) and the ability of recombinant erythropoietin (Epo) to augment this vasodilator mechanism in the spastic arteries were studied.

METHODS

Recombinant adenoviral vectors (10(9) plaque-forming units per animal) encoding genes for human Epo (AdEpo), and beta-galactosidase were injected immediately after injection of autologous arterial blood into the cisterna magna (day 0) of rabbits. Cerebral angiography was performed on day 0 and day 2, and basilar arteries were harvested for Western blots, measurement of cGMP levels, and analysis of vasomotor functions.

RESULTS

Injection of autologous arterial blood into cisterna magna resulted in significant vasospasm of the basilar arteries. Despite the narrowing of arterial diameter and reduced expression of eNOS, expressions of phosphorylated protein kinase B (Akt) and phosphorylated eNOS were significantly increased in spastic arteries. Gene transfer of AdEpo reversed the vasospasm. AdEpo-transduced basilar arteries demonstrated significant augmentation of the endothelium-dependent relaxations to acetylcholine, whereas the relaxations to an NO donor, 2-(N,N-diethylamino)diazenolate-2-oxide sodium salt, were not affected. Transduction with AdEpo further increased the expression of phosphorylated Akt and eNOS and elevated basal levels of cGMP in the spastic arteries.

CONCLUSIONS

Phosphorylation of eNOS appears to be an adaptive mechanism activated during development of vasospasm. The vascular protective effect of Epo against cerebral vasospasm induced by SAH may be mediated in part by phosphorylation of Akt/eNOS.

Cyclosporine Decreases Vascular Progenitor Cell Numbers After Cardiac Transplantation and Attenuates Progenitor Cell Growth in Vitro

OBJECTIVE

Recent experimental evidence suggests that the neointimal proliferation seen in cardiac allograft vasculopathy may in part derive from recipient progenitor cells. The effect of cyclosporine on these circulating progenitors in the setting of cardiac transplantation is currently unknown.

METHODS

Three surgical series were performed: sham operation alone, sham operation with immunosuppression, and heterotopic porcine cardiac transplantation with immunosuppression. The sham operation involved laparotomy and consecutive clamping of the abdominal aorta and inferior vena cava. Post-operative immunosuppression consisted of cyclosporine at therapeutic levels (100-300 ng/ml) and 0.5 mg/kg methylprednisolone. Endothelial outgrowth colony numbers (EOC(CFU)) and smooth muscle outgrowth colony numbers (SOC(CFU)) were quantified weekly for 4 weeks post-operatively. A series of in vitro experiments were performed to determine the effect of cyclosporine on the differentiation, migration, and proliferation of EOCs and SOCs.

RESULTS

In the sham alone series there were no changes to either EOC(CFU) or SOC(CFU). In the sham with immunosuppression and the transplant series, both EOC(CFU) and SOC(CFU) fell in the first 2 weeks (p < 0.05) compared with baseline (EOC(CFU), 3.4 +/- 0.6; SOC(CFU), 11.1 +/- 2.8). EOC(CFU) recovered at 4 weeks to above baseline levels in the sham immunosuppression group only (15.2 +/- 3.9; p = 0.01). SOC(CFU) showed no recovery in the immunosuppression groups. Cyclosporine, even at a low dose, prevented differentiation, inhibited proliferation, and attenuated migration of both EOCs and SOCs.

CONCLUSION

Immunosuppression in the setting of cardiac transplantation causes a profound reduction in circulating progenitor cells capable of differentiating into endothelial and smooth muscle cells. This effect can in part be explained by the inhibitory effects of cyclosporine on progenitor growth and differentiation seen in this study.

Limited (6-h) ambulatory blood pressure monitoring is a valid replacement for the office blood pressure by trained nurse clinician in the diagnosis of hypertension

OBJECTIVE

To assess the ability of limited ambulatory blood pressure monitoring as a valid replacement for office blood pressure measurement done to American Heart Association criteria in diagnosing hypertension.

METHODS

In all, 105 adults, who had been referred for limited ambulatory blood pressure monitoring, participated in the study. Limited ambulatory blood pressure monitoring consisted of 6 h of blood pressure measurement while ambulatory at the Mayo Clinic, using a SpaceLabs 90207 (SpaceLabs Medical, Issaquah, Washington, USA) collecting six readings per hour for the period of observation. The study participants gave consent for three additional consecutive office blood pressure measurements, using a validated aneroid device, done to American Heart Association criteria, by a single hypertension nurse specialist.

RESULTS

Mean systolic blood pressure by limited ambulatory blood pressure monitoring was 137.9+/-14.2 mmHg and for the nurse, 137.9+/-20.1 mmHg. Mean diastolic blood pressure by limited ambulatory blood pressure monitoring was 81.5+/-9.7 mmHg and for the nurse, 74.3+/-11.9 mmHg. The intermethod difference for systolic blood pressure was 0.03+/-12.5 mmHg and diastolic blood pressure, -7.2+/-8.0 mmHg. Using <140/90 as criteria factor, limited ambulatory blood pressure monitoring and the trained nurse agreed 77% of the time on whether the patient was hypertensive. This agreement increased to 81% if the participant's referral blood pressure was >or=140/90.

CONCLUSIONS

Limited ambulatory blood pressure monitoring is an excellent replacement for office blood pressure, done to American Heart Association criteria, in diagnosing hypertension. This avoids issues of variability introduced by the observers, such as digit preference and bias, and increases reproducibility of blood pressure measurements. The appropriate normal value for limited ambulatory blood pressure monitoring is <140/90 mmHg compared with <135/85 mmHg used in 24-h ambulatory blood pressure monitoring.

Time trends of ischemic stroke incidence and mortality in patients diagnosed with first atrial fibrillation in 1980 to 2000: report of a community-based study

BACKGROUND AND PURPOSE

With the changes in management of atrial fibrillation (AF) over time, it is possible that the time trends of post-AF stroke incidence and mortality have changed. We sought to determine whether the incidence and survival of ischemic stroke after AF diagnosis have improved.

METHODS

We identified the Olmsted County, Minn, residents who developed first AF from 1980 to 2000 and followed them in medical records to 2004. The outcomes were first ischemic stroke and death.

RESULTS

Of the 4117 subjects diagnosed with first AF and without previous stroke, 446 (11%) sustained a first ischemic stroke during a mean follow-up time of 5.5+/-5.0 years. The age- and sex-adjusted incidence of stroke decreased, on average, by 3.4% per year (P=0.0001), concurrent with an increase in warfarin and aspirin use (both P<0.0001) and reduction of systolic blood pressure (P<0.001). The age-adjusted ischemic stroke incidence was higher in women (P=0.039), but not after adjusting for systolic blood pressure (P=0.41). Compared with the general Minnesota white population, the relative mortality hazard ratio was 1.88 for men and 1.84 for women without stroke and 3.03 for men and 3.80 for women (P<0.05) with stroke. The relative mortality hazard did not vary by age or calendar year of AF diagnosis.

CONCLUSIONS

Post-AF ischemic stroke incidence decreased significantly from 1980 to 2000, during which time a substantial increase in the use of antithrombotic therapy and reduction of systolic blood pressure was evident. The relative mortality risk of stroke, however, had not improved over time.

Sinus Venosus Atrial Septal Defect

Background— Sinus venosus atrial septal defect (SVASD) differs from secundum atrial septal defect by its atrial septal location and its association with anomalous pulmonary venous connection (APVC). Data on long-term outcome after surgical repair are limited.

Methods and Results— We reviewed outcomes of 115 patients (mean age±SD 34±23 years) with SVASD who had repair from 1972 through 1996. APVC was present in 112 patients (97%). Early mortality was 0.9%. Complete follow-up was obtained for 108 patients (95%) at 144±99 months. Symptomatic improvement was noted in 83 patients (77%), and deterioration was noted in 17 patients (16%). At follow-up, 7 (6%) of 108 patients had sinus node dysfunction, a permanent pacemaker, or both, and 15 (14%) of 108 patients had atrial fibrillation. Older age at repair was predictive of postoperative atrial fibrillation ( P =0.033). No reoperations were required during follow-up. Survival was not different from expected for an age- and sex-matched population. Clinical improvement was more common with older age at surgery ( P =0.014). Older age at repair ( P =0.008) and preoperative New York Heart Association class III or IV ( P =0.038) were independent predictors of late mortality.

Conclusions— Operation for SVASD is associated with low morbidity and mortality, and postoperative subjective clinical improvement occurs irrespective of age at surgery. Postoperative atrial fibrillation appears to be related to older age at operation. SVASD repair achieves survival similar to that of a matched population and should be considered whenever repair may impact survival or symptoms.

Usefulness of left atrial volume in predicting first congestive heart failure in patients > or = 65 years of age with well-preserved left ventricular systolic function

Left atrial (LA) volume is a barometer of diastolic dysfunction. Whether it predicts congestive heart failure (CHF) in patients with preserved left ventricular (LV) systolic function is not known. Olmsted County, Minnesota, residents aged > or = 65 years referred for transthoracic echocardiography from 1990 to 1998, who were in sinus rhythm without a history of CHF were followed in the medical records to 2003 (mean follow-up duration 4.3 +/- 2.7 years). Of the 1,495 patients identified, 1,375 (92%) with LV ejection fractions > or = 50% (mean age 75 +/- 7 years; 59% women) constituted the study population, 138 (10%) of whom developed CHF. Baseline LA volume > or = 32 ml/m2 was an independent predictor of first CHF (p <0.001). Of the 138 patients who had first CHF, ejection fractions were assessed within 4 weeks of diagnosis in 98 subjects, 74 (76%) of whom had ejection fractions remaining at > or = 50%, with a mean increase in LA volume of 8 +/- 10 ml/m2 (p <0.001) from baseline. The age-adjusted CHF-free survival rates for LA volume tertiles (< 28, 28 to < or = 37, and > 37 ml/m2) were 95%, 91%, and 83%, respectively (p <0.001). In conclusion, LA volume independently predicted first CHF in an elderly cohort with well-preserved LV systolic function.

Left atrial volume predicts cardiovascular events in patients originally diagnosed with lone atrial fibrillation: three-decade follow-up

AIMS

The objectives of this study were to determine the long-term outcome and the predictors of adverse events in patients originally diagnosed with lone atrial fibrillation (AF).

METHODS AND RESULTS

This population-based historical cohort study comprised 46 residents of Olmsted County, MN, USA, with well-documented, clinically defined lone AF and a complete two-dimensional echocardiographic examination. The original echocardiographic videotape recordings were analysed in a blinded fashion for left atrial volume (LAV) and left ventricular ejection fraction. With 1296 person-years of follow-up, the median duration of AF was 27 (first quartile=24, third quartile=33) years. Twenty-three (50%) patients developed events. Cerebral infarction occurred in seven patients, myocardial infarction in 11, and congestive heart failure in 16. In a multivariable analysis, patients with indexed LAV >or=32 mL/m(2) had a significantly worse event-free survival (adjusted HR, 4.46; 95% CI, 1.56-12.74; P=0.005). All cerebral infarctions occurred in patients with an indexed LAV >32 mL/m(2).

CONCLUSION

Patients originally diagnosed with benign lone AF follow divergent courses based on LAV. Those originally diagnosed with lone AF and normal sized atria had a benign clinical course throughout the long-term follow-up. Patients with increased LAV at diagnosis or later during the follow-up experienced adverse events.

C-reactive protein is related to arterial wave reflection and stiffness in asymptomatic subjects from the community

BACKGROUND

Emerging data suggest that C-reactive protein (CRP), a marker of inflammation, is associated with functional properties of arteries. We investigated the relationship of CRP to measures of arterial wave reflection and stiffness (aortic augmentation index [AIX], carotid-femoral pulse wave velocity [PWV], and pulse pressure) in asymptomatic individuals from the community.

METHODS

Subjects (n = 214) had a mean age of 59 years and 53% were men. CRP was measured by a high-sensitivity assay and values were log-transformed to reduce skewness. Radial artery waveforms were obtained by applanation tonometry, a validated transfer function was used to derive an ascending aortic pressure waveform, and AIX calculated. PWV was calculated from electrocardiogram-gated waveforms of the right carotid and right femoral artery obtained by applanation tonometry.

RESULTS

Log CRP was correlated with AIX (r = 0.24, P = .0005), PWV (r = 0.25, P = .0002), and pulse pressure (r = 0.29, P < or = .0001). In separate backward elimination multiple regression analyses, log CRP was significantly associated with AIX (P = .038) and pulse pressure (P = .036), and marginally significantly associated with PWV (P = .054), after adjustment for heart rate, height, and coronary heart disease (CHD) risk factors (age, sex, body mass index, mean arterial pressure, total cholesterol, HDL cholesterol, diabetes, hypertension, and history of smoking).

CONCLUSIONS

These results suggest that CRP, a marker of systemic inflammation, is related to measures of arterial wave reflection and stiffness in asymptomatic subjects from the community. Further studies are needed to understand the mechanisms underlying this association and the implications for assessment and management of CHD risk.

Outcome of 622 adults with asymptomatic, hemodynamically significant aortic stenosis during prolonged follow-up

BACKGROUND

This study assessed the long-term outcome of a large, asymptomatic population with hemodynamically significant aortic stenosis (AS).

METHODS AND RESULTS

We identified 622 patients with isolated, asymptomatic AS and peak systolic velocity > or =4 m/s by Doppler echocardiography who did not undergo surgery at the initial evaluation and obtained follow-up (5.4+/-4.0 years) in all. Mean age (+/-SD) was 72+/-11 years; there were 384 (62%) men. The probability of remaining free of cardiac symptoms while unoperated was 82%, 67%, and 33% at 1, 2, and 5 years, respectively. Aortic valve area and left ventricular hypertrophy predicted symptom development. During follow-up, 352 (57%) patients were referred for aortic valve surgery and 265 (43%) patients died, including cardiac death in 117 (19%). The 1-, 2-, and 5-year probabilities of remaining free of surgery or cardiac death were 80%, 63%, and 25%, respectively. Multivariate predictors of all-cause mortality were age (hazard ratio [HR], 1.05; P<0.0001), chronic renal failure (HR, 2.41; P=0.004), inactivity (HR, 2.00; P=0.001), and aortic valve velocity (HR, 1.46; P=0.03). Sudden death without preceding symptoms occurred in 11 (4.1%) of 270 unoperated patients. Patients with peak velocity > or =4.5 m/s had a higher likelihood of developing symptoms (relative risk, 1.34) or having surgery or cardiac death (relative risk, 1.48).

CONCLUSIONS

Most patients with asymptomatic, hemodynamically significant AS will develop symptoms within 5 years. Sudden death occurs in approximately 1%/y. Age, chronic renal failure, inactivity, and aortic valve velocity are independently predictive of all-cause mortality.

Relationships between insulin sensitivity and measures of body fat in asymptomatic men and women

OBJECTIVE

To assess whether measures of body fat by DXA scanning can improve prediction of insulin sensitivity (S(I)) beyond what is possible with traditional measures, such as BMI, waist circumference, and waist-to-hip ratio (WHR).

RESEARCH METHODS AND PROCEDURES

Frequently sampled intravenous glucose tolerance tests were performed in 256 asymptomatic non-Hispanic white subjects from Rochester, MN (age 19-60 years; 123 men and 133 women) to determine the S(I) index by Bergman's minimal model technique. Height, weight, and waist and hip circumferences were measured for calculation of BMI and WHR; DXA was used to determine fat in the head, upper body, abdomen, and lower body. Linear regression was used to assess their relationships with S(I) after sex stratification and adjustment for age.

RESULTS

After controlling for age, increases in traditional and DXA measures of fat were consistently associated with smaller declines in S(I) among women than among men. In men, after controlling for age, all of the predictive information of S(I) was provided by waist circumference (additional R2 = 0.39, p < 0.001); none of the DXA measures improved the ability to predict S(I). In women, after adjustment for age, BMI, and WHR, the only DXA measure that improved the prediction of S(I) was percentage head fat (additional R2 = 0.03, p < 0.001).

DISCUSSION

Equivalent increases in most measures of body fat had lesser impact on S(I) in women than in men. In both sexes, the predictive information provided by DXA measures is approximately equal to, but not additive to, that provided by simpler, traditional measures.

Semi-parametric and non-parametric methods for clinical trials with incomplete data

Last observation carried forward (LOCF) and analysis using only data from subjects who complete a trial (Completers) are commonly used techniques for analysing data in clinical trials with incomplete data when the endpoint is change from baseline at last scheduled visit. We propose two alternative methods. The semi-parametric method, which cumulates changes observed between consecutive time points, is conceptually similar to the familiar life-table method and corresponding Kaplan-Meier estimation when the primary endpoint is time to event. A non-parametric analogue of LOCF is obtained by carrying forward, not the observed value, but the rank of the change from baseline at the last observation for each subject. We refer to this method as the LRCF method. Both procedures retain the simplicity of LOCF and Completers analyses and, like these methods, do not require data imputation or modelling assumptions. In the absence of any incomplete data they reduce to the usual two-sample tests. In simulations intended to reflect chronic diseases that one might encounter in practice, LOCF was observed to produce markedly biased estimates and markedly inflated type I error rates when censoring was unequal in the two treatment arms. These problems did not arise with the Completers, Cumulative Change, or LRCF methods. Cumulative Change and LRCF were more powerful than Completers, and the Cumulative Change test provided more efficient estimates than the Completers analysis, in all simulations. We conclude that the Cumulative Change and LRCF methods are preferable to LOCF and Completers analyses. Mixed model repeated measures (MMRM) performed similarly to Cumulative Change and LRCF and makes somewhat less restrictive assumptions about missingness mechanisms, so that it is also a reasonable alternative to LOCF and Completers analyses.

Diastolic stress echocardiography: a novel noninvasive diagnostic test for diastolic dysfunction using supine bicycle exercise Doppler echocardiography

Left ventricular filling pressures can be estimated reliably by combining mitral inflow early diastolic velocity (E) and annulus velocity (E'). An increased E/E' ratio reflects elevated filling pressures and may be useful in assessing an abnormal increase in filling pressures for patients with diastolic dysfunction. The purpose of this study was to evaluate the feasibility of supine bicycle exercise Doppler echocardiography for assessing left ventricular diastolic pressure during exercise. Mitral inflow and septal mitral annulus velocities were measured at rest and during supine bicycle exercise (25-W 3-minute increments) in 45 patients (19 men; mean age, 59 years) referred for evaluation of exertional dyspnea. None had echocardiographic or electrocardiographic evidence of myocardial ischemia with exercise. Patients were classified according to E/E' ratio at rest: 26 had E/E' < or = 10 at rest (group 1) and 19 had E/E' > 10 (group 2). For group 1, 17 had no increase in E/E' during exercise (group 1A) and 9 did (group 1B). For group 2, E/E' did not increase during exercise. Despite different responses of E/E', there was no significant difference in changes of mitral inflow indices (E, A, E/A, deceleration time) between groups. Although the percentage of dyspnea as a primary reason for stopping exercise was similar for the groups, exercise duration was significantly shorter for groups 1B (7.2 +/- 2.5 minutes) and 2 (7.1 +/- 3.3 minutes) than in group 1A (10.4 +/- 3.7 minutes, P = .0129). Diastolic stress echocardiography using a supine bicycle is technically feasible for demonstrating changes in E/E' (filling pressure) with exercise. Our preliminary results suggest the hemodynamic consequences of exercise-induced increase in diastolic filling pressure can be demonstrated noninvasively with exercise Doppler echocardiography.

Carvedilol therapy is associated with a sustained decline in brain natriuretic peptide levels in patients with congestive heart failure

BACKGROUND

Beta-blocker therapy improves symptoms, left ventricular ejection fraction (LVEF), and survival in patients with congestive heart failure, but chronic effects on neurohormones have not been extensively investigated. Therefore, we examined the neurohumoral effects of carvedilol.

METHODS

Fifty-five patients with New York Heart Association (NYHA) classes II-III congestive heart failure and LVEF < or =35% entered the study with intention to assess LVEF, NYHA class, plasma brain natriuretic peptide (BNP), N-terminal atrial natriuretic peptide (NANP), big-endothelin, endothelin-1, norepinephrine, and angiotensin II at baseline and at 6 and 12 months after initiation of carvedilol.

RESULTS

Forty-six patients completed 12 months of follow-up. Left ventricular ejection fraction improved from 26% +/- 8% at baseline to 39% +/- 14% at 12 months. New York Heart Association class improved from 2.3 +/- 0.4 at baseline to 1.8 +/- 0.7 at 12 months. Brain natriuretic peptide fell from 453 +/- 784 to 208 +/- 393 pg/mL at 6 months and 223 +/- 334 pg/mL at 12 months ( P = .01 vs baseline). N-terminal atrial natriuretic peptide did not change between baseline and 6 months but fell at 12 months (2117 +/- 1678, 2015 +/- 1532, and 1438 +/- 1442 pg/mL, respectively, P = .001 between baseline and 12 months). Angiotensin II was lower at 6 and 12 months than at baseline (12.6 +/- 10, 7.8 +/- 5.5 pg/mL, P < 0.001, and 11.3 +/- 17.1 pg/mL, P = .02, respectively). Left ventricular ejection fraction at 12 months correlated inversely with BNP level at 12 months (r = -0.55, P = .001).

CONCLUSIONS

Carvedilol therapy is associated with a sustained decline in BNP and NANP levels. Serial BNP levels can provide some guidance regarding probability of LVEF improvement, but the relationship is not strong enough for BNP levels to supplant measurement of LVEF.

Prognostic significance of chronotropic response to dobutamine stress echocardiography in patients with peripheral arterial disease

Chronotropic response is important during exercise stress testing. Less is known about its role after dobutamine stress echocardiography. In addition, limited information exists regarding the long-term prognostic value of dobutamine stress echocardiography in patients who have peripheral arterial disease. We studied 2,138 patients who had peripheral arterial disease (1,317 men, 70 +/- 10 years old) and who underwent dobutamine stress echocardiography. Follow-up was completed for all-cause mortality and cardiovascular morbidity (nonfatal myocardial infarction and coronary revascularization). Death and cardiovascular morbidity occurred in 961 patients (45%) and 348 patients (16%), respectively, during a follow-up of 6.1 +/- 2.7 years. Failure to achieve 85% of age-predicted maximal heart rate (hazard ratio [HR] 1.34, 95% confidence interval [CI] 1.16 to 1.54, p = 0.0001) and percent of abnormal segments at peak stress (HR/10% increment 1.04, 95% CI 1.01 to 1.07, p = 0.02) were independent predictors of mortality and morbidity (HR 1.35, 95% CI 1.06 to 1.71, p = 0.01 and HR 1.14, 95% CI 1.08 to 1.20, p <0.0001, respectively). The effect of not achieving the target heart rate during normal dobutamine stress echocardiography on 1-, 3-, 5-, and 10-year survival probabilities was comparable to that of ischemia (86% vs 88%, 75% vs 71%, 62% vs 59%, and 33% vs 32%, respectively; p = 0.8). In a stepwise multivariate model, dobutamine stress echocardiography had incremental value over clinical data and echocardiographic data at rest for predicting rates of mortality (model chi-square increase from 301 to 322, p <0.0001) and morbidity (model chi-square increase from 37 to 118, p <0.0001). In conclusion, chronotropic response and extent of abnormal segments at peak dobutamine stress provide incremental prognostic information in patients who have peripheral arterial disease.

Lack of association between lipoprotein(a) and coronary artery calcification in the Genetic Epidemiology Network of Arteriopathy (GENOA) study

OBJECTIVE

To investigate the relationship between lipoprotein(a) [Lp(a)] levels and the extent of coronary atherosclerosis in a cohort that consisted predominantly of hypertensive patients.

PATIENTS AND METHODS

Patients were ascertained through sibships that contained at least 2 individuals with essential hypertension diagnosed before the age of 60 years. The 10-year coronary heart disease (CHD) risk was estimated on the basis of the Framingham risk equation. Serum Lp(a) was measured by an immunoturbidimetric assay. Coronary artery calcification (CAC) was measured noninvasively by electron beam computed tomography and CAC score calculated using the Agatston score.

RESULTS

Patients included 765 non-Hispanic, white individuals (59% women) participating in the Genetic Epidemiology Network of Arteriopathy study. The mean +/- SD age of the patients was 62 +/- 8 years, and 77% had hypertension. The prevalence of detectable CAC was 87% in men and 60% in women. The CAC scores did not differ significantly across quintiles of Lp(a) levels in either men or women. In a multiple regression model that included conventional risk factors, Lp(a) levels were not related to CAC quantity in either sex. No significant interactions were noted between Lp(a) levels and the conventional risk factors in the prediction of CAC quantity. When stratified on the basis of the 10-year CHD risk, 26.5% of the patients were low risk (< 6%), 60.5% were intermediate risk (6%-20%), and 12.9% were high risk (> 20%). Lipoprotein(a) was not associated with CAC quantity within subgroups based on 10-year CHD risk.

CONCLUSION

In this cohort enriched with hypertensive patients, the estimated 10-year CHD risk did not appear to modify the lack of an association between Lp(a) levels and CAC.

Ethnic differences in peripheral arterial disease in the NHLBI Genetic Epidemiology Network of Arteriopathy (GENOA) study

Few studies have investigated whether ethnic groups differ in the prevalence of peripheral arterial disease (PAD). We compared the distribution of the ankle-brachial index (ABI), a measure of PAD, between African Americans and non-Hispanic white individuals. Subjects (n = 931) belonged to the Genetic Epidemiology Network of Arteriopathy (GENOA) study, a community-based study of hypertensive sibships, and included 453 African Americans from Jackson, Mississipi (mean age 72 +/- 6 years, 69% women) and 478 non-Hispanic white individuals from Rochester, Minnesota (mean age 58 +/- 7 years, 64% women). ABI was determined at two sites in each lower extremity and the lowest of four indices was used in the analyses. PAD was defined as an ABI of < or = 0.95. Information about conventional risk factors was derived from interviews and from blood samples drawn at the study visit. The prevalence of diabetes and hypertension was significantly higher in African Americans than in non-Hispanic white individuals. After adjusting for age, African American subjects had a lower mean ABI (women 0.97 vs 1.04, p < 0.001; men 0.96 vs 1.12, p < 0.001) and a greater prevalence of PAD (women 34% vs 22%, p = 0.010; men 33% vs 11%, p < 0.001) than their non-Hispanic white counterparts. In multiple regression analyses, African American ethnicity was a predictor of a lower ABI and the presence of PAD in each sex after adjusting for age and other conventional risk factors. In conclusion, the lower ABI and greater prevalence of PAD in African Americans than in non-Hispanic white individuals is not explained by differences in conventional risk factors. Identifying additional 'novel' risk factors that account for the ethnic differences in PAD is an important next step towards understanding why such differences exist and developing more effective strategies to reduce the burden of PAD.

Low-density lipoprotein particle size and coronary atherosclerosis in subjects belonging to hypertensive sibships

BACKGROUND

Dyslipidemia in hypertensive sibships may be characterized by atherogenic small low-density lipoprotein (LDL) particles. Whether LDL particle size is associated with the extent of coronary atherosclerosis in hypertensive sibships is unknown.

METHODS

Subjects (n = 792, mean age 62 years, 60% women) were ascertained through sibships containing at least two individuals with essential hypertension diagnosed before age 60 years. The LDL particle size was measured by polyacrylamide gel electrophoresis. Coronary artery calcium (CAC) was measured noninvasively by electron beam computed tomography, and CAC score was calculated using the method of Agatston et al. Sex-specific multiple regression models were used to assess independent predictors of LDL particle size and the association of LDL particle size with CAC.

RESULTS

In all, 76% of women and 77% of men were hypertensive. In each sex, independent predictors of smaller LDL particle size were total cholesterol, triglycerides, and lower HDL cholesterol. In women, greater age was an additional predictor of smaller LDL particle size. After adjustment for age and statin use, LDL particle size was significantly associated with the amount of CAC in women but not in men. After further adjustment for HDL cholesterol, triglycerides, diabetes, smoking, and hypertension, LDL particle size was not independently associated with CAC in either sex.

CONCLUSIONS

After adjustment for age and statin use, LDL particle size was found to be significantly related to CAC quantity in women but not in men belonging to hypertensive sibships. In women, LDL particle size may mediate some of the atherogenic effects of low-HDL cholesterol-high-triglyceride dyslipidemia, but does not appear to be independently associated with the extent of coronary atherosclerosis in either sex.

Participation bias in a population-based echocardiography study

PURPOSE

To compare the characteristics of participants and non-participants in a population-based study of cardiac ventricular function.

METHODS

Subjects aged 45 years and older on January 1, 1997 were recruited from a sampling frame of Olmsted County residents from the Rochester Epidemiology Project. Subjects were asked to complete a 17-page questionnaire and participate in a 4-hour clinical examination that included a brief physical examination, echocardiography, spirometry, and an electrocardiogram. With specific IRB approval, the community medical records of participants and non-participants from the first wave of recruitment were examined by trained nurse abstractors to elicit details of past medical history.

RESULTS

Of the first 963 persons invited to participate in the study, 488 (51%) completed all phases of the examination. Participation rates were similar among men and women (53% vs. 49%, respectively). By age, participation rates were lowest among persons aged 75 years and older (44.7% and 34.9%) and 45 to 54 years (45.4% and 44.3%) for men and women. Participation rates were not different according to past history of coronary heart disease, congestive heart failure, or other cardiovascular disease. Persons with a history of chronic obstructive pulmonary disease were less likely to participate (19.4% vs. 51%; odds ratio, 0.36; 95% confidence interval, 0.18, 0.76) after adjustment for age, sex, and comorbid conditions.

CONCLUSIONS

These results provide some reassurance that participation bias in this study may have little influence on its overall findings, although this cannot be conclusive.