Podocyturia predates proteinuria and clinical features of preeclampsia: longitudinal prospective study

Podocyturia, the shedding of live podocytes, is present at delivery in women with preeclampsia. The aim of this study was to test whether podocyturia is present earlier in pregnancy and predicts for preeclampsia. We also aimed to compare test characteristics of podocyturia with those of angiogenic factors previously implicated in the pathogenesis of this disorder. We prospectively enrolled 315 women who provided blood and urine samples at the end of the second trimesters of their pregnancies (median, 27 gestational weeks) and within 24 hours of their deliveries (median, 39.5 gestational weeks). Blood samples were analyzed for angiogenic markers, including placental growth factor, the soluble receptor fms-like tyrosine kinase receptor-1 for vascular endothelial growth factor, and endoglin. The urine sediments were analyzed for podocytes, identified by staining for podocin after culturing the urinary sediments for 24 hours. This analysis included all women who developed preeclampsia (n=15), gestational hypertension (n=15), and a subsample of women who remained normotensive throughout pregnancy (n=44), matched for maternal age and number of previous pregnancies to those who developed preeclampsia. At the second trimester collection, all women who developed preeclampsia had podocyturia, compared with none of those who remained normotensive or were diagnosed with gestational hypertension. Podocyturia in the second trimester had a significantly greater sensitivity and specificity for the subsequent diagnosis of preeclampsia than any single angiogenic marker or a combination thereof. Screening for podocyturia at the end of the second trimester may allow for accurate identification of pregnant women at risk for preeclampsia.

Bias in recording of body mass index data in the electronic health record

The relationship between patient disease status and the presence or absence of body mass index (BMI) data in the electronic health record (EHR) has not been characterized. We conducted a descriptive study of the completeness of BMI data for three patient cohorts. Cross-sectional descriptions of BMI presence rates per patient were compared between a cohort having at least one ICD-9-CM code for diabetes mellitus (DM) versus a cohort with no diagnosis constraints. Conversely, frequencies of encounter diagnoses were compared among subgroups having BMI recorded or not in both cohorts described and a third cohort having DM codes from a separate organization's EHR. The data demonstrate a correlation with presence of BMI and higher disease status. This effect may bias the cohort average BMIs, which appear higher than expected. When EHR BMI data are repurposed for research, biases in the selective recording of BMI may affect the results.

Hypertension susceptibility loci and blood pressure response to antihypertensives: results from the pharmacogenomic evaluation of antihypertensive responses study

BACKGROUND

To date, 39 single nucleotide polymorphisms (SNPs) have been associated with blood pressure (BP) or hypertension in genome-wide association studies in whites. Our hypothesis is that the loci/SNPs associated with BP/hypertension are also associated with BP response to antihypertensive drugs.

METHODS AND RESULTS

We assessed the association of these loci with BP response to atenolol or hydrochlorothiazide monotherapy in 768 hypertensive participants in the Pharmacogenomics Responses of Antihypertensive Responses study. Linear regression analysis was performed on whites for each SNP in an additive model adjusting for baseline BP, age, sex, and principal components for ancestry. Genetic scores were constructed to include SNPs with nominal associations, and empirical P values were determined by permutation test. Genotypes of 37 loci were obtained from Illumina 50K cardiovascular or Omni1M genome-wide association study chips. In whites, no SNPs reached Bonferroni-corrected α of 0.0014, 6 reached nominal significance (P<0.05), and 3 were associated with atenolol BP response at P<0.01. The genetic score of the atenolol BP-lowering alleles was associated with response to atenolol (P=3.3 × 10(-6) for systolic BP; P=1.6 × 10(-6) for diastolic BP). The genetic score of the hydrochlorothiazide BP-lowering alleles was associated with response to hydrochlorothiazide (P=0.0006 for systolic BP; P=0.0003 for diastolic BP). Both risk score P values were <0.01 based on the empirical distribution from the permutation test.

CONCLUSIONS

These findings suggest that selected signals from hypertension genome-wide association studies may predict BP response to atenolol and hydrochlorothiazide when assessed through risk scoring. Clinical Trial Registration Information- clinicaltrials.gov; Identifier: NCT00246519.

Ethnic differences in low-density lipoprotein particle size in hypertensive adults

BACKGROUND

Hypertensive African Americans have higher rates of coronary heart disease (CHD) than their non-Hispanic white counterparts despite having higher HDL cholesterol (HDL-C) levels and lower triglyceride levels.

OBJECTIVE

The goal of the present study was to assess whether low-density lipoprotein (LDL) particle size, a correlate of the above lipid traits and a risk factor for CHD, differs between hypertensive African Americans and whites.

METHODS

Participants included 1177 hypertensive African Americans from Jackson MS (60+/-7 years, 72.4% women) and 860 hypertensive whites from Rochester MN (58+/-7 years, 56.7% women). LDL particle size was measured by polyacrylamide gradient gel electrophoresis. Within each sex, we assessed whether ethnicity was significantly associated with differences in LDL particle size after adjustment for CHD risk factors (age, total cholesterol, HDL-C, triglycerides, systolic BP, diabetes, history of smoking, body mass index), statin use, and estrogen use (in women), and "lifestyle" variables (physical activity and alcohol intake).

RESULTS

Although HDL-C levels were higher and triglyceride levels lower in African Americans, LDL particle size (adjusted for CHD risk factors) was lower (P < 0.0001) in African American men and women than in their white counterparts (mean +/- SD; men, 267.6+/-5.2 A vs. 270.2+/-4.8 A; women 268.7+/-5.1 A vs. 271.3+/-5.1 A). In both sexes, African American ethnicity was associated with lower LDL particle size after adjustment for CHD risk factors, statin use and estrogen use (in women), as well as physical activity and alcohol intake.

CONCLUSION

Hypertensive African American men and women have lower LDL particle size than their white counterparts despite having higher HDL-C and lower triglycerides.

G protein receptor kinase 4 polymorphisms: β-blocker pharmacogenetics and treatment-related outcomes in hypertension

G protein-coupled receptor kinases (GRKs) are important regulatory proteins for many G protein-coupled receptors, but little is known about GRK4 pharmacogenetics. We hypothesized that 3 nonsynonymous GRK4 single-nucleotide polymorphisms, R65L (rs2960306), A142V (rs1024323), and A486V (rs1801058), would be associated with blood pressure response to atenolol, but not hydrochlorothiazide, and would be associated with long-term cardiovascular outcomes (all-cause death, nonfatal myocardial infarction, nonfatal stroke) in participants treated with an atenolol-based versus verapamil-SR-based antihypertensive strategy. GRK4 single-nucleotide polymorphisms were genotyped in 768 hypertensive participants from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) trial. In whites and blacks, increasing copies of the variant 65L-142V haplotype were associated with significantly reduced atenolol-induced diastolic blood pressure lowering (-9.1±6.8 versus -6.8±7.1 versus -5.3±6.4 mm Hg in participants with 0, 1, and 2 copies of 65L-142V, respectively; P=0.0088). One thousand four hundred sixty participants with hypertension and coronary artery disease from the INternational VErapamil SR/Trandolapril STudy (INVEST) were genotyped, and variant alleles of all 3 GRK4 single-nucleotide polymorphisms were associated with increased risk for adverse cardiovascular outcomes in an additive fashion, with 486V homozygotes reaching statistical significance (odds ratio, 2.29 [1.48-3.55]; P=0.0002). These effects on adverse cardiovascular outcomes were independent of antihypertensive treatment. These results suggest that the presence of GRK4 variant alleles may be important determinants of blood pressure response to atenolol and risk for adverse cardiovascular events. The associations with GRK4 variant alleles were stronger in patients who were also ADRB1 389R homozygotes, suggesting a potential interaction between these 2 genes.

Venous thromboembolism in nursing home residents: role of selected risk factors

OBJECTIVES

To provide nursing home (NH)-specific estimates to assess whether venous thromboembolism (VTE) risk factors identified for the general population apply to NH residents.

DESIGN

Population-based case-control study.

SETTING

Olmsted County, Minnesota.

PARTICIPANTS

All county residents with symptomatic objectively diagnosed incident VTE while resident in a NH from 1988 through 2000 (N = 182) and two age-, sex-, calendar-year-matched non-VTE Olmsted County NH residents per case (N = 364).

MEASUREMENTS

Provider-linked medical records were reviewed to obtain information on active malignancy and recent hospitalization, surgery, trauma, or fracture as of index date (case's VTE date; respective provider registration date for controls). Risk factor prevalence and VTE-associated odds ratios (OR) were estimated and compared with previously obtained data for all Olmsted County residents from 1988 through 2000. For analyses, both groups were limited to individuals aged 65 and older.

RESULTS

In NH residents, active malignancy, recent hospitalization, and recent surgery significantly increased VTE risk, but the magnitude of risk appeared much lower than general population estimates (e.g., for major surgery, OR = 2.5, 95% confidence interval (CI) = 1.4-4.3 for NH residents vs OR = 11, 95% CI = 7.0-17 for general population). In general, the prevalence of all evaluated VTE risk factors appeared much higher in NH controls than in general population controls. Thromboprophylaxis rates appeared higher for NH cases and controls than in the general population; disconcertingly, 47% of NH cases received prophylaxis.

CONCLUSION

Although general population VTE risk factors (active cancer and recent hospitalization or surgery) can identify NH residents at higher risk for VTE, these exposures do not adequately stratify VTE risk for thromboprophylaxis recommendations. Further research into NH-specific risk factors and prophylaxis effectiveness is required.

Genomic association analysis identifies multiple loci influencing antihypertensive response to an angiotensin II receptor blocker

To identify genes influencing blood pressure response to an angiotensin II receptor blocker, single nucleotide polymorphisms identified by genome-wide association analysis of the response to candesartan were validated by opposite direction associations with the response to a thiazide diuretic, hydrochlorothiazide. We sampled 198 white and 193 blacks with primary hypertension from opposite tertiles of the race-sex-specific distributions of age-adjusted diastolic blood pressure response to candesartan. There were 285 polymorphisms associated with the response to candesartan at P<10(-4) in whites. A total of 273 of the 285 polymorphisms, which were available for analysis in a separate sample of 196 whites, validated for opposite direction associations with the response to hydrochlorothiazide (Fisher χ(2) 1-sided P=0.02). Among the 273 polymorphisms, those in the chromosome 11q21 region were the most significantly associated with response to candesartan in whites (eg, rs11020821 near FUT4, P=8.98 × 10(-7)), had the strongest opposite direction associations with response to hydrochlorothiazide (eg, rs3758785 in GPR83, P=7.10 × 10(-3)), and had the same direction associations with response to candesartan in the 193 blacks (eg, rs16924603 near FUT4, P=1.52 × 10(-2)). Also notable among the 273 polymorphisms was rs11649420 on chromosome 16 in the amiloride-sensitive sodium channel subunit SCNN1G involved in mediating renal sodium reabsorption and maintaining blood pressure when the renin-angiotensin system is inhibited by candesartan. These results support the use of genomewide association analyses to identify novel genes predictive of opposite direction associations with blood pressure responses to inhibitors of the renin-angiotensin and renal sodium transport systems.

Effects of genetic variation in H3K79 methylation regulatory genes on clinical blood pressure and blood pressure response to hydrochlorothiazide

BACKGROUND

Nearly one-third of the United States adult population suffers from hypertension. Hydrochlorothiazide (HCTZ), one of the most commonly used medications to treat hypertension, has variable efficacy. The renal epithelial sodium channel (ENaC) provides a mechanism for fine-tuning sodium excretion, and is a major regulator of blood pressure homeostasis. DOT1L, MLLT3, SIRT1, and SGK1 encode genes in a pathway that controls methylation of the histone H3 globular domain at lysine 79 (H3K79), thereby modulating expression of the ENaCα subunit. This study aimed to determine the role of variation in these regulatory genes on blood pressure response to HCTZ, and secondarily, untreated blood pressure.

METHODS

We investigated associations between genetic variations in this candidate pathway and HCTZ blood pressure response in two separate hypertensive cohorts (clinicaltrials.gov NCT00246519 and NCT00005520). In a secondary, exploratory analysis, we measured associations between these same genetic variations and untreated blood pressure. Associations were measured by linear regression, with only associations with P ≤ 0.01 in one cohort and replication by P ≤ 0.05 in the other cohort considered significant.

RESULTS

In one cohort, a polymorphism in DOT1L (rs2269879) was strongly associated with greater systolic (P = 0.0002) and diastolic (P = 0.0016) blood pressure response to hydrochlorothiazide in Caucasians. However, this association was not replicated in the other cohort. When untreated blood pressure levels were analyzed, we found directionally similar associations between a polymorphism in MLLT3 (rs12350051) and greater untreated systolic (P < 0.01 in both cohorts) and diastolic (P < 0.05 in both cohorts) blood pressure levels in both cohorts. However, when further replication was attempted in a third hypertensive cohort and in smaller, normotensive samples, significant associations were not observed.

CONCLUSIONS

Our data suggest polymorphisms in DOT1L, MLLT3, SIRT1, and SGK1 are not likely associated with blood pressure response to HCTZ. However, a possibility exists that rs2269879 in DOT1L could be associated with HCTZ response in Caucasians. Additionally, exploratory analyses suggest rs12350051 in MLLT3 may be associated with untreated blood pressure in African-Americans. Replication efforts are needed to verify roles for these polymorphisms in human blood pressure regulation.

Power to identify a genetic predictor of antihypertensive drug response using different methods to measure blood pressure response

BACKGROUND

To determine whether office, home, ambulatory daytime and nighttime blood pressure (BP) responses to antihypertensive drug therapy measure the same signal and which method provides greatest power to identify genetic predictors of BP response.

METHODS

We analyzed office, home, ambulatory daytime and nighttime BP responses in hypertensive adults randomized to atenolol (N = 242) or hydrochlorothiazide (N = 257) in the Pharmacogenomic Evaluation of Antihypertensive Responses Study. Since different measured BP responses may have different predictors, we tested the "same signal" model by using linear regression methods to determine whether known predictors of BP response depend on the method of BP measurement. We estimated signal-to-noise ratios and compared power to identify a genetic polymorphism predicting BP response measured by each method separately and by weighted averages of multiple methods.

RESULTS

After adjustment for pretreatment BP level, known predictors of BP response including plasma renin activity, race, and sex were independent of the method of BP measurement. Signal-to-noise ratios were more than 2-fold greater for home and ambulatory daytime BP responses than for office and ambulatory nighttime BP responses and up to 11-fold greater for weighted averages of all four methods. Power to identify a genetic polymorphism predicting BP response was directly related to the signal-to-noise ratio and, therefore, greatest with the weighted averages.

CONCLUSION

Since different methods of measuring BP response to antihypertensive drug therapy measure the same signal, weighted averages of the BP responses measured by multiple methods minimize measurement error and optimize power to identify genetic predictors of BP response.

Survival in patients with poorly compressible leg arteries

OBJECTIVES

This study sought to compare survival of patients with poorly compressible arteries (PCA) to those with a normal ankle-brachial index (ABI) and those with peripheral arterial disease (PAD).

BACKGROUND

Limited data are available regarding survival in patients with PCA identified in the clinical setting by noninvasive lower extremity arterial evaluation.

METHODS

We conducted a historical cohort study of consecutive patients who underwent outpatient, noninvasive lower extremity arterial evaluation at the Mayo Clinic, Rochester, Minnesota, from January 1998 through December 2007, and who were followed for a mean duration of 5.8 ± 3.1 years. An ABI 1.00 to 1.30 was considered normal, PAD was defined as a resting or post-exercise ABI ≤0.90, and PCA defined as an ABI ≥1.4 and/or an ankle systolic blood pressure >255 mm Hg. Patients were followed for all-cause mortality through September 30, 2009.

RESULTS

Of 16,493 individuals (mean age 67.8 ± 13.0 years, 59% male); 29% had normal ABI, 54% had PAD, and 17% had PCA. During follow-up (mean duration 5.8 ± 3.1 years), 4,365 patients (26%) died. The percent alive at the end of the study period was 88%, 70%, and 60% for normal ABI, PAD, and PCA, respectively. After adjustment for age, sex, cardiovascular risk factors, comorbid conditions, and medication use, the hazard ratios (95% confidence intervals) of death associated with PCA were 2.0 (1.8 to 2.2) and 1.3 (1.2 to 1.4) compared with the normal ABI and PAD groups, respectively.

CONCLUSIONS

Patients identified by noninvasive vascular testing to have poorly compressible leg arteries have poor survival, worse than those with a normal ABI or those with PAD.

Comparison of natural language processing biosurveillance methods for identifying influenza from encounter notes

BACKGROUND

An effective national biosurveillance system expedites outbreak recognition and facilitates response coordination at the federal, state, and local levels. The BioSense system, used at the Centers for Disease Control and Prevention, incorporates chief complaints but not data from the whole encounter note into its surveillance algorithms.

OBJECTIVE

To evaluate whether biosurveillance by using data from the whole encounter note is superior to that using data from the chief complaint field alone.

DESIGN

6-year retrospective case-control cohort study.

SETTING

Mayo Clinic, Rochester, Minnesota.

PARTICIPANTS

17,243 persons tested for influenza A or B virus between 1 January 2000 and 31 December 2006.

MEASUREMENTS

The accuracy of a model based on signs and symptoms to predict influenza virus infection in patients with upper respiratory tract symptoms, and the ability of a natural language processing technique to identify definitional clinical features from free-text encounter notes.

RESULTS

Surveillance based on the whole encounter note was superior to the chief complaint field alone. For the case definition used by surveillance of the whole encounter note, the normalized partial area under the receiver-operating characteristic curve (specificity, 0.1 to 0.4) for surveillance using the whole encounter note was 92.9% versus 70.3% for surveillance with the chief complaint field (difference, 22.6%; P < 0.001). Comparison of the 2 models at the fixed specificity of 0.4 resulted in sensitivities of 89.0% and 74.4%, respectively (P < 0.001). The relative risk for missing a true case of influenza was 2.3 by using the chief complaint field model.

LIMITATIONS

Participants were seen at 1 tertiary referral center. The cost of comprehensive biosurveillance monitoring was not studied.

CONCLUSION

A biosurveillance model for influenza using the whole encounter note is more accurate than a model that uses only the chief complaint field. Because case-defining signs and symptoms of influenza are commonly available in health records, the investigators believe that the national strategy for biosurveillance should be changed to incorporate data from the whole health record.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention.

Predictive utility of atrial, N-terminal pro-atrial, and N-terminal pro-B-type natriuretic peptides for mortality and cardiovascular events in the general community: a 9-year follow-up study

OBJECTIVE

To determine the predictive value of atrial natriuretic peptide (ANP), N-terminal pro-ANP (NT-proANP), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) for mortality and cardiovascular events in the general population in the absence of overt heart failure (HF).

PARTICIPANTS AND METHODS

We identified a community-based cohort of 2042 individuals. Those with stage C or D HF (n=45) and renal insufficiency (n=6) were excluded from the current study. Of the remaining individuals, 1769 (89%) underwent echocardiography and measurement of plasma ANP, NT-proANP, and NT-proBNP. Participants were followed up from January 1, 1997, to May 1, 2009, for mortality, HF, myocardial infarction (MI), and cerebrovascular accident; median follow-up was 9 years.

RESULTS

After adjustment for conventional clinical risk factors, NT-proANP had significant predictive value for mortality but not for HF, MI, or cerebrovascular accident, whereas ANP lacked any predictive value. The predictive value of NT-proANP for mortality was attenuated after adjustment for structural and functional cardiac abnormalities. In contrast, NT-proBNP had predictive value for mortality, HF, and MI after adjustment for conventional risk factors and retained significance for mortality and HF after adjustment for structural and functional cardiac abnormalities.

CONCLUSION

Our results suggest that NT-proBNP is a more robust cardiac biomarker compared with ANP or NT-proANP and is independently predictive of mortality and HF in the general population free of overt HF.

Serum N-terminal pro-B-type natriuretic peptide levels are associated with functional capacity in patients with peripheral arterial disease

We hypothesized that higher serum levels of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) are associated with lower functional capacity in patients with peripheral arterial disease ([PAD] n = 481, mean age 67, 68% men). Functional capacity was quantified as distance walked on a treadmill for 5 minutes. Patients were divided into 3 groups according to the distance walked: >144 yards (group 1, n = 254); 60 to 144 yards (group 2, n = 80); <60 yards or did not walk (group 3, n = 147). The association between NT-pro-BNP levels and the ordinal 3-level walking distance was assessed using multivariable ordinal logistic regression analyses that adjusted for several possible confounding variables. Higher levels of NT-pro-BNP were associated with a lower ordinal walking category independent of possible confounders (odds ratio [OR] 1.51, 95% confidence interval [CI] 1.28-1.77; P < .001). In conclusion, higher levels of NT-pro-BNP are independently associated with lower functional capacity in patients with PAD and may be a marker of hemodynamic stress in these patients.

Genotype-informed estimation of risk of coronary heart disease based on genome-wide association data linked to the electronic medical record

Background

Susceptibility variants identified by genome-wide association studies (GWAS) have modest effect sizes. Whether such variants provide incremental information in assessing risk for common 'complex' diseases is unclear. We investigated whether measured and imputed genotypes from a GWAS dataset linked to the electronic medical record alter estimates of coronary heart disease (CHD) risk.

Methods

Study participants (n = 1243) had no known cardiovascular disease and were considered to be at high, intermediate, or low 10-year risk of CHD based on the Framingham risk score (FRS) which includes age, sex, total and HDL cholesterol, blood pressure, diabetes, and smoking status. Of twelve SNPs identified in prior GWAS to be associated with CHD, four were genotyped in the participants as part of a GWAS. Genotypes for seven SNPs were imputed from HapMap CEU population using the program MACH. We calculated a multiplex genetic risk score for each patient based on the odds ratios of the susceptibility SNPs and incorporated this into the FRS.

Results

The mean (SD) number of risk alleles was 12.31 (1.95), range 6-18. The mean (SD) of the weighted genetic risk score was 12.64 (2.05), range 5.75-18.20. The CHD genetic risk score was not correlated with the FRS (P = 0.78). After incorporating the genetic risk score into the FRS, a total of 380 individuals (30.6%) were reclassified into higher-(188) or lower-risk groups (192).

Conclusion

A genetic risk score based on measured/imputed genotypes at 11 susceptibility SNPs, led to significant reclassification in the 10-y CHD risk categories. Additional prospective studies are needed to assess accuracy and clinical utility of such reclassification.

The SHARPn project on secondary use of Electronic Medical Record data: progress, plans, and possibilities

SHARPn is a collaboration among 16 academic and industry partners committed to the production and distribution of high-quality software artifacts that support the secondary use of EMR data. Areas of emphasis are data normalization, natural language processing, high-throughput phenotyping, and data quality metrics. Our work avails the industrial scalability afforded by the Unstructured Information Management Architecture (UIMA) from IBM Watson Research labs, the same framework which underpins the Watson Jeopardy demonstration. This descriptive paper outlines our present work and achievements, and presages our trajectory for the remainder of the funding period. The project is one of the four Strategic Health IT Advanced Research Projects (SHARP) projects funded by the Office of the National Coordinator in 2010.

Diastolic dysfunction in patients undergoing cardiac surgery: a pathophysiological mechanism underlying the initiation of new-onset post-operative atrial fibrillation

OBJECTIVES

Our goal was to investigate whether left ventricular (LV) diastolic dysfunction was an important pathophysiological mechanism underlying the initiation of new-onset post-operative atrial fibrillation (POAF).

BACKGROUND

Atrial fibrillation is a common complication after cardiac surgery. However, the precise mechanism underlying its development remains poorly understood. Pre-existing alterations of myocardial diastolic function may predispose patients to the development of POAF.

METHODS

Patients were residents of Olmsted County, Minnesota, who underwent complete LV diastolic function assessment before coronary artery bypass grafting and/or valve surgery between January 1, 2000, and December 31, 2005. All were in sinus rhythm and had no history of atrial fibrillation, a pacemaker, mitral stenosis, or congenital heart disease. POAF was defined as any episode of atrial fibrillation within 30 days after surgery.

RESULTS

POAF occurred in 135 of 351 patients (38.5%). Patients with POAF were older (mean age 72.5 ± 10.3 years vs. 63.1 ± 14.1 years; p < 0.001) and more likely to have abnormal diastolic function. The rate of POAF increased exponentially with diastolic function grade (DFG) severity (p < 0.001). By multivariate analysis, after adjusting for clinical and surgical risk factors, independent predictors of POAF were older age (odds ratio [OR]: 1.05; p < 0.001), higher body mass index (OR: 1.06; p = 0.03), and abnormal LV DFG (DFG 1, OR: 5.12 [p = 0.006]; DFG 2, OR: 9.87 [p < 0.001]; and DFG 3, OR: 28.52 [p < 0.001]).

CONCLUSIONS

LV diastolic dysfunction is a powerful, independent predisposing substrate for the initiation of POAF. Evaluation may be useful during risk stratification of patients undergoing cardiac surgery.

A genetic variant of the atrial natriuretic peptide gene is associated with cardiometabolic protection in the general community

OBJECTIVES

We sought to define the cardiometabolic phenotype associated with rs5068, a genetic variant of the atrial natriuretic peptide (ANP) gene.

BACKGROUND

The ANP and B-type natriuretic peptide play an important role in cardiorenal homeostasis but also exert metabolic actions.

METHODS

We genotyped 1,608 randomly selected residents from Olmsted County, Minnesota. Subjects were well-characterized.

RESULTS

Genotype frequencies were: AA 89.9%, AG 9.7%, and GG 0.4%; all subsequent analyses were AA versus AG+GG. The G allele was associated with increased plasma levels of N-terminal pro-atrial natriuretic peptide (p = 0.002), after adjustment for age and sex. The minor allele was also associated with lower body mass index (BMI) (p = 0.006), prevalence of obesity (p = 0.002), waist circumference (p = 0.021), lower levels of C-reactive protein (p = 0.027), and higher values of high-density lipoprotein cholesterol (p = 0.019). The AG+GG group had a lower systolic blood pressure (p = 0.011) and lower prevalence of myocardial infarction (p = 0.042). The minor allele was associated with a lower prevalence of metabolic syndrome (p = 0.025). The associations between the G allele and high-density lipoprotein cholesterol, C-reactive protein values, myocardial infarction, and metabolic syndrome were not significant, after adjusting for BMI; the associations with systolic blood pressure, BMI, obesity, and waist circumference remained significant even after adjusting for N-terminal pro-atrial natriuretic peptide.

CONCLUSIONS

In a random sample of the general U.S. population, the minor allele of rs5068 is associated with a favorable cardiometabolic profile. These findings suggest that rs5068 or genetic loci in linkage disequilibrium might affect susceptibility for cardiometabolic diseases and support the possible protective role of natriuretic peptides by their favorable effects on metabolic function. Replication studies are needed to confirm our findings.

Alterations in platelet function and cell-derived microvesicles in recently menopausal women: relationship to metabolic syndrome and atherogenic risk

A woman's risk for metabolic syndrome (MS) increases at menopause, with an associated increase in risk for cardiovascular disease. We hypothesized that early menopause-related changes in platelet activity and concentrations of microvesicles derived from activated blood and vascular cells provide a mechanistic link to the early atherothrombotic process. Thus, platelet functions and cellular origin of blood-borne microvesicles in recently menopausal women (n = 118) enrolled in the Kronos Early Estrogen Prevention Study were correlated with components of MS and noninvasive measures of cardiovascular disease [carotid artery intima medial thickness (CIMT), coronary artery calcium (CAC) score, and endothelial reactive hyperemic index (RHI)]. Specific to individual components of the MS pentad, platelet number increased with increasing waist circumference, and platelet secretion of ATP and expression of P-selectin decreased with increasing blood glucose (p = 0.005) and blood pressure (p < 0.05), respectively. Waist circumference and systolic blood pressure were independently associated with monocyte- and endothelium-derived microvesicles (p < 0.05). Platelet-derived and total procoagulant phosphatidylserine-positive microvesicles, and systolic blood pressure correlated with CIMT (p < 0.05), but not with CAC or RHI. In summary, among recently menopausal women, specific platelet functions and concentrations of circulating activated cell membrane-derived procoagulant microvesicles change with individual components of MS. These cellular changes may explain in part how menopause contributes to MS and, eventually, to cardiovascular disease.

Frailty across the spectrum of ankle-brachial index

We investigated the burden of frailty across the spectrum of ankle-brachial index (ABI < 0.9, 0.9 ≤ ABI < 1.1, 1.1 ≤ ABI < 1.4 and ≥1.4) using data from the National Health and Nutritional Examination Survey (NHANES) in respondents aged >50 years. Criteria used to identify frailty status included weight loss, slow walking speed, weakness, exhaustion, and low physical activity. Participants meeting 1 to 2 criteria were classified as prefrail, and those meeting ≥3 criteria were classified as frail. Prevalence of frailty in respondents with ABI < 0.9 (17.5%) and 0.9 ≤ ABI < 1.1 (6.7%) was higher than in participants with normal ABI-1.1 ≤ ABI < 1.4 (4.7%). In multivariable multinomial logistic regression models, ABI < 0.9 predicted frailty (odds ratio [OR] = 2.31, 95% confidence interval [CI] = 1.08-4.94) and prefrailty (OR = 1.36, 95% CI = 0.90-2.07). Higher prevalence of frailty was seen in participants with ABI ≥ 1.4 (7.3%), P = .39. Frailty predicted general and cardiovascular mortality in participants with ABI < 0.9. Frailty mediates increased morbidity and mortality seen in peripheral arterial disease (PAD).

The association of active cancer with venous thromboembolism location: a population-based study

OBJECTIVE

To test active cancer for an association with venous thromboembolism (VTE) location.

PATIENTS AND METHODS

Using the resources of the Rochester Epidemiology Project, we identified all Olmsted County, MN, residents with incident VTE during the 35-year period 1966-2000 (N = 3385). We restricted analyses to residents with objectively diagnosed VTE during the 17-year period from January 1, 1984, to December 31, 2000 (N = 1599). For each patient, we reviewed the complete medical records in the community for patient age, gender, and most recent body mass index at VTE onset; VTE event type and location; and previously identified independent VTE risk factors (ie, surgery, hospitalization for acute medical illness, active cancer, leg paresis, superficial venous thrombosis, and varicose veins). Using logistic regression we tested active cancer for an association with each of 4 symptomatic VTE locations (arm or intra-abdominal deep venous thrombosis [DVT], intra-abdominal DVT, pulmonary embolism, and bilateral leg DVT), adjusted for age, gender, body mass index, and other VTE risk factors.

RESULTS

In multivariate analyses, active cancer was independently associated with arm or intra-abdominal DVT (odds ratio [OR], 1.76; P = .01), intra-abdominal DVT (OR, 2.22; P = .004), and bilateral leg DVT (OR, 2.09; P = .02), but not pulmonary embolism (OR, 0.93).

CONCLUSION

Active cancer is associated with VTE location. Location of VTE may be useful in decision making regarding cancer screening.

Genome-wide association analyses of genetic, phenotypic, and environmental risks in the age-related eye disease study

PURPOSE

To present genome-wide association analyses of genotypic and environmental risks on age-related macular degeneration (AMD) using 593 subjects from the age-related eye disease study (AREDS), after adjusting for population stratification and including questionable controls.

METHODS

Single nucleotide polymorphism (SNP) associations with AMD for the non-Hispanic white population were investigated using a log-additive model after adjusting for population stratification. Replication of possible SNP-disease association was performed by genotyping an independent group of 444 AMD case and 300 control subjects. Logistic regression models were used to assess interaction effects between smoking and SNPs associated with AMD. Independent genetic risk effects among the disease-associated SNPs were also investigated using multiple logistic regression models.

RESULTS

Population stratification was observed among the individuals having a self-reported race of non-Hispanic white. Risk allele frequencies at established AMD loci demonstrated that questionable control subjects were similar to control subjects in the AREDS, suggesting that they could be used as true controls in the analyses. Genetic loci (complement factor H [CFH], complement factor B [CFB], the age-related maculopathy susceptibility 2 locus containing the hypothetical gene [LOC387715]/the high-temperature requirement A-1 [HTRA1], and complement component 3 [C3]) that were already known to be associated with AMD were identified. An additional 26 novel SNPs potentially associated with AMD were identified, but none were definitely replicated in a second independent group of subjects. Smoking did not interact with known AMD loci, but was associated with late AMD. Statistically independent genetic signals were observed within the Pleckstrin homology domain-containing family A member 1 (PLEKHA1) region near LOC387715/HTRA1 and within a haplotype spanning exon 19 of the C3 gene.

CONCLUSIONS

Population stratification among Caucasian subjects from the multicentered AREDS was observed, suggesting that it should be adjusted for in future studies. The AREDS questionable control subjects can be used as control subjects in the AREDS genome-wide association study (GWAS). Smoking was an independent risk factor for advanced AMD in the AREDS subjects. There continues to be evidence that the 10q26 (age-related maculopathy susceptibility 2 gene [ARMS2]) locus spanning PLEKHA1-LOC387715-HTRA1 and the C3 gene may contain multiple independent genetic risks contributing to AMD.

Submaximal exercise gas exchange is an important prognostic tool to predict adverse outcomes in heart failure

AIMS

Traditionally, VO(2peak) has been used to determine prognosis in heart failure; however, this measure has limitations. Hence, other exercise and gas exchange parameters measured submaximally, e.g. breathing efficiency (V(E)/VCO(2)), end-tidal CO(2) (P(ET)CO(2)), oxygen uptake efficiency slope (OUES), and circulatory power [ systolic blood pressure (SBP)], have been investigated. The aim of this study was to investigate the prognostic relevance of submaximal exercise gas exchange in heart failure patients. Method and results One hundred and thirty-two consecutive heart failure patients (mean age 56 ± 12 years, ejection fraction 29 ± 11%) performed peak treadmill testing. Gas exchange and haemodynamic variables were measured continuously. Gas exchange data obtained from the first 2 min of exercise and at a respiratory exchange ratio (RER) of 0.9 were the measurements of interest. Over a median follow-up period of 62.4 (range 0-114) months, there were 44 endpoints (death or transplant). Univariate analysis demonstrated submaximal predictors of survival, which included V(E)/VCO(2) slope and ratio, P(ET)CO(2), OUES, and circulatory power (P ≤ 0.01). When these and additional submaximal variables were included together in the multivariable analysis, the strongest submaximal exercise predictive model (C-statistic 0.75) comprised data from the first stage of exercise (V(E) and circulatory power) and at an RER of 0.9 (V(E)/VCO(2) ratio). The inclusion of VO(2 peak) and demographic data, with submaximal data (V(E)/VCO(2) ratio at an RER = 0.9), increased the predictiveness of the model (C-statistic 0.78).

CONCLUSION

Submaximal exercise measures provide useful prognostic information for predicting survival in heart failure. This form of testing is logistically easier, cheaper, and safer for patients compared with maximal exercise.

Impact of venous thromboembolism, venous stasis syndrome, venous outflow obstruction and venous valvular incompetence on quality of life and activities of daily living: a nested case-control study

The role of venous stasis syndrome (VSS) mechanisms (i.e. venous outflow obstruction [VOO] and venous valvular incompetence [VVI]) on quality of life (QoL) and activities of daily living (ADL) is unknown. The objective of this study was to test the hypotheses that venous thromboembolism (VTE),VSS,VOO and VVI are associated with reduced QoL and ADL. This study is a follow-up of an incident VTE case-control study nested within a population-based inception cohort of residents from Olmsted County, MN, USA, between 1966 and 1990. The study comprised 232 Olmsted County residents with a first lifetime VTE and 133 residents without VTE. Methods included a questionnaire and physical examination for VSS; vascular laboratory testing for VOO and VVI; assessment of QoL by SF36 and of ADL by pertinent sections from the Older Americans Resources and Services (OARS) and Arthritis Impact Measurement Scales (AIMS2) questionnaires. Of the 365 study participants, 232 (64%), 161 (44%), 43 (12%) and 136 (37%) had VTE, VSS, VOO and VVI, respectively. Prior VTE was associated with reduced ADL and increased pain, VSS with reduced physical QoL and increased pain, and VOO with reduced physical QoL and ADL.VVI was not associated with QoL or ADL. In conclusion,VSS and VOO are associated with worse physical QoL and increased pain. VOO and VTE are associated with impaired ADL. We hypothesize that rapid clearance of venous outflow obstruction in individuals with acute VTE will improve their QoL and ADL.

Endothelial function and cardiovascular risk stratification in menopausal women

BACKGROUND

Peripheral arterial, endothelium-dependent, flow-mediated reactive hyperemia is reduced in individuals with atherosclerosis. This study tested the hypothesis that digital tonometry, as a surrogate of endothelial function, is useful to stratify cardiovascular risk in recently menopausal women who are asymptomatic for cardiovascular disease.

METHODS

Women undergoing screening for the Kronos Early Estrogen Prevention Study (KEEPS) were evaluated for conventional risk factors, flow-mediated reactive hyperemia by digital tonometry (RHI), carotid intima-media thickness (CIMT) by ultrasound, and coronary arterial calcium (CAC) by 64-slice CT scanner.

RESULTS

One hundred and two non-diabetic Caucasian women (53.0 +/- 2.3 years old, 18.0 +/- 9.0 months past their last menses) participated; 72% were never-smokers. Fourteen women had positive CAC scores (range 0.5-133 Agatston units); CIMT ranged from 0.57 to 1.06 mm. RHI ranged from 1.26 to 5.44. RHI did not correlate with time past menopause, CAC, CIMT, total cholesterol or low density lipoprotein cholesterol. The significant negative correlation of RHI with body mass index (r = -0.21, p = 0.031) was lost in non-smokers (r = - 0.17, p = 0.14). There was also a negative correlation of high density lipoprotein cholesterol with CAC, both in the overall group and non-smokers (rho = -0.20, p = 0.05 and rho = -0.27, p = 0.02, respectively).

CONCLUSIONS

RHI varies widely in healthy women within the first 3 years of menopause. RHI was not associated with standard risk assessment algorithms, CAC or CIMT. RHI may indicate an additional, independent component and non-invasive tool to further stratify cardiovascular risk in recently menopausal women. As KEEPS continues, data on RHI will provide information regarding hormonal therapy, endovascular biology and atherosclerotic risk.

Is progestin an independent risk factor for incident venous thromboembolism? A population-based case-control study

INTRODUCTION

Because the risk of venous thromboembolism (VTE) associated with progestin is uncertain, we tested oral contraceptives, estrogen and progestin as independent VTE risk factors.

MATERIALS AND METHODS

Using longitudinal, population-based Rochester Epidemiology Project resources, we identified all Olmsted County, MN women with objectively-diagnosed incident VTE over the 13-year period, 1988-2000 (n=726) and one to two Olmsted County women per case matched on age, event year and duration of prior medical history (n=830), and reviewed their complete medical history in the community for previously-identified VTE risk factors (i.e., hospitalization with or without surgery, nursing home confinement, trauma/fracture, leg paresis, active cancer, varicose veins and pregnancy/postpartum), and oral contraceptive, oral estrogen, and oral or injectable progestin exposure. Using conditional logistic regression we tested these hormone exposures as VTE risk factors, both unadjusted and after adjusting for previously-identified VTE risk factors.

RESULTS

In unadjusted models, oral contraceptives, progestin alone, and estrogen plus progestin were significantly associated with VTE. Individually adjusting for body mass index (BMI) and previously-identified VTE risk factors, these effects remained essentially unchanged except that progestin alone was not associated with VTE after adjusting for active cancer. Considering only case-control pairs without active cancer, progestin alone was positively but non-significantly associated with VTE (OR=2.49; p=0.16). Adjusting for BMI and previously-identified VTE risk factors including active cancer, oral contraceptives, estrogen alone, and progestin with or without estrogen were significantly associated with VTE.

CONCLUSIONS

Oral contraceptives, estrogen alone, estrogen plus progestin, and progestin with or without estrogen are independent VTE risk factors.

E2-2 protein and Fuchs's corneal dystrophy

BACKGROUND

Fuchs's corneal dystrophy (FCD) is a leading cause of corneal transplantation and affects 5% of persons in the United States who are over the age of 40 years. Clinically visible deposits called guttae develop under the corneal endothelium in patients with FCD. A loss of endothelial cells and deposition of an abnormal extracellular matrix are observed microscopically. In advanced disease, the cornea swells and becomes cloudy because the remaining endothelial cells are not sufficient to keep the cornea dehydrated and clear. Although rare genetic variation that contributes to both early-onset and typical late-onset forms of FCD has been identified, to our knowledge, no common variants have been reported.

METHODS

We performed a genomewide association study and replicated the most significant observations in a second, independent group of subjects.

RESULTS

Alleles in the transcription factor 4 gene (TCF4), encoding a member of the E-protein family (E2-2), were associated with typical FCD (P=2.3x10(-26)). The association increased the odds of having FCD by a factor of 30 for persons with two copies of the disease variants (homozygotes) and discriminated between case subjects and control subjects with about 76% accuracy. At least two regions of the TCF4 locus were associated independently with FCD. Alleles in the gene encoding protein tyrosine phosphatase receptor type G (PTPRG) were associated with FCD (P=4.0x10(-7)), but the association did not reach genomewide significance.

CONCLUSIONS

Genetic variation in TCF4 contributes to the development of FCD. (Funded by the National Eye Institute and others.)

Plasma renin activity predicts blood pressure responses to beta-blocker and thiazide diuretic as monotherapy and add-on therapy for hypertension

BACKGROUND

Age and race categories or renin profiling have been recommended to predict blood pressure responses to monotherapy with a beta-blocker or thiazide diuretic. Whether these or other characteristics predict blood pressure responses when the drugs are administered as add-on therapy is uncertain.

METHODS

We evaluated predictors of blood pressure response in 363 men and women < or =65 years of age with primary hypertension (152 blacks, 211 whites), 86 of whom (24%) were untreated and 277 of whom (76%) were withdrawn from previous antihypertensive drugs before randomization to either atenolol followed by addition of hydrochlorothiazide (N = 180) or hydrochlorothiazide followed by addition of atenolol (N = 183). Responses were determined by home blood pressure averages before and after each drug administration. Race, age, plasma renin activity, and other characteristics including pretreatment blood pressure levels were incorporated into linear regression models to quantify their contributions to prediction of blood pressure responses.

RESULTS

Plasma renin activity and pretreatment blood pressure level consistently contributed to prediction of systolic and diastolic responses to each drug administered as mono- and as add-on therapy. Higher plasma renin activity was consistently associated with greater blood pressure responses to atenolol and lesser responses to hydrochlorothiazide. The predictive effects of plasma renin activity were statistically independent of race, age, and other characteristics.

CONCLUSIONS

Plasma renin activity and pretreatment blood pressure level predict blood pressure responses to atenolol and hydrochlorothiazide administered as mono- and as add-on therapy in men and women < or =65 years of age.

A systematic review and meta-analysis of pregnancy outcomes in patients with systemic lupus erythematosus and lupus nephritis

BACKGROUND AND OBJECTIVES

Studies of the impact of systemic lupus erythematosus (SLE) and its pregnancy complications have yielded conflicting results. Major limitations of these studies relate to their small numbers of patients and retrospective designs. The aim of this study was to perform a systematic literature review of pregnancy outcomes in women with SLE and a meta-analysis of the association of lupus nephritis with adverse pregnancy outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We searched electronic databases from 1980 to 2009 and reviewed papers with validity criteria. Random-effects analytical methods were used to evaluate pregnancy complications rates.

RESULTS

Thirty-seven studies with 1842 patients and 2751 pregnancies were included. Maternal complications included lupus flare (25.6%), hypertension (16.3%), nephritis (16.1%), pre-eclampsia (7.6%), and eclampsia (0.8%). The induced abortion rate was 5.9%, and when excluded, fetal complications included spontaneous abortion (16.0%), stillbirth (3.6%), neonatal deaths (2.5%), and intrauterine growth retardation (12.7%). The unsuccessful pregnancy rate was 23.4%, and the premature birth rate was 39.4%. Meta-regression analysis showed statistically significant positive associations between premature birth rate and active nephritis and increased hypertension rates in subjects with active nephritis or a history of nephritis. History of nephritis was also associated with pre-eclampsia. Anti-phospholipid antibodies were associated with hypertension, premature birth, and an increased rate of induced abortion.

CONCLUSIONS

In patients with SLE, both lupus nephritis and anti-phospholipid antibodies increase the risks for maternal hypertension and premature births. The presented evidence further supports timing of pregnancy relative to SLE activity and multispecialty care of these patients.

Spatial normalization improves the quality of genotype calling for Affymetrix SNP 6.0 arrays

Background

Microarray measurements are susceptible to a variety of experimental artifacts, some of which give rise to systematic biases that are spatially dependent in a unique way on each chip. It is likely that such artifacts affect many SNP arrays, but the normalization methods used in currently available genotyping algorithms make no attempt at spatial bias correction. Here, we propose an effective single-chip spatial bias removal procedure for Affymetrix 6.0 SNP arrays or platforms with similar design features. This procedure deals with both extreme and subtle biases and is intended to be applied before standard genotype calling algorithms.

Results

Application of the spatial bias adjustments on HapMap samples resulted in higher genotype call rates with equal or even better accuracy for thousands of SNPs. Consequently the normalization procedure is expected to lead to more meaningful biological inferences and could be valuable for genome-wide SNP analysis.

Conclusions

Spatial normalization can potentially rescue thousands of SNPs in a genetic study at the small cost of computational time. The approach is implemented in R and available from the authors upon request.

Regulation of circulating progenitor cells in left ventricular dysfunction

BACKGROUND

Reductions in numbers of circulating progenitor cells (CD34+ cell subsets) have been demonstrated in patients at risk for, or in the presence of, cardiovascular disease. The mediators of these reductions remain undefined. To determine whether neurohumoral factors might regulate circulating CD34+ cell subsets in vivo, we studied complementary canine models of left ventricular (LV) dysfunction.

METHODS AND RESULTS

A pacing model of severe LV dysfunction and a hypertensive renal wrap model in which dogs were randomized to receive deoxycorticosterone acetate (DOCA) were studied. Circulating CD34+ cell subsets including hematopoietic precursor cells (HPCs: CD34+/CD45(dim)/VEGFR2-) and endothelial progenitor cells (EPCs: CD34+/CD45-/VEGFR2+) were quantified. Additionally, the effect of mineralocorticoid excess on circulating progenitor cells in normal dogs was studied. The majority of circulating CD34+ cells expressed CD45dimly and did not express VEGFR2, consistent with an HPC phenotype. HPCs were decreased in response to pacing, and this decrease correlated with plasma aldosterone levels (Spearman rank correlation=-0.67, P=0.03). In the hypertensive renal wrap model, administration of DOCA resulted in decreased HPCs. No changes were seen in EPCs in either model. Normal dogs treated with DOCA exhibited a decrease in HPCs in peripheral blood but not bone marrow associated with decreased telomerase activity.

CONCLUSIONS

This is the first study to demonstrate that mineralocorticoid excess, either endogenous or exogenous, results in reduction in HPCs. These data suggest that mineralocorticoids may induce accelerated senescence of progenitor cells, leading to their reduced survival and decline in numbers.

Conference Scene: The great debate: genome-wide association studies in pharmacogenetics research, good or bad?

Will genome-wide association studies (GWAS) 'work' for pharmacogenetics research? This question was the topic of a staged debate, with pro and con sides, aimed to bring out the strengths and weaknesses of GWAS for pharmacogenetics studies. After a full day of seminars at the Fifth Statistical Analysis Workshop of the Pharmacogenetics Research Network, the lively debate was held--appropriately--at Goonies Comedy Club in Rochester (MN, USA). The pro side emphasized that the many GWAS successes for identifying genetic variants associated with disease risk show that it works; that the current genotyping platforms are efficient, with good imputation methods to fill in missing data; that its global assessment is always a success even if no significant associations are detected; and that genetic effects are likely to be large because humans have not evolved in a drug-therapy environment. By contrast, the con side emphasized that we have limited knowledge of the complexity of the genome; limited clinical phenotypes compromise studies; the likely multifactorial nature of drug response clouding the small genetic effects; and limitations of sample size and replication studies in pharmacogenetic studies. Lively and insightful discussions emphasized further research efforts that might benefit GWAS in pharmacogenetics.

The prognostic value of N-terminal pro-B-type natriuretic peptide for death and cardiovascular events in healthy normal and stage A/B heart failure subjects

OBJECTIVES

Our objective was to determine the prognostic value of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) for death and cardiovascular events among subjects without risk factors for heart failure (HF), which we term healthy normal.

BACKGROUND

Previous studies report that plasma NT-proBNP has prognostic value for cardiovascular events in the general population even in the absence of HF. It is unclear if NT-proBNP retains predictive value in healthy normal subjects.

METHODS

We identified a community-based cohort of 2,042 subjects in Olmsted County, Minnesota. Subjects with symptomatic (stage C/D) HF were excluded. The remaining 1,991 subjects underwent echocardiography and NT-proBNP measurement. We further defined healthy normal (n = 703) and stage A/B HF (n = 1,288) subgroups. Healthy normal was defined as the absence of traditional clinical cardiovascular risk factors and echocardiographic structural cardiac abnormalities. Subjects were followed for death, HF, cerebrovascular accident, and myocardial infarction with median follow-up of 9.1, 8.7, 8.8, and 8.9 years, respectively.

RESULTS

NT-proBNP was not predictive of death or cardiovascular events in the healthy normal subgroup. Similar to previous reports, in stage A/B HF, plasma NT-proBNP values greater than age-/sex-specific 80th percentiles were associated with increased risk of death, HF, cerebrovascular accident, and myocardial infarction (p < 0.001 for all) even after adjustment for clinical risk factors and structural cardiac abnormalities.

CONCLUSIONS

These findings do not support the use of NT-proBNP as a cardiovascular biomarker in healthy normal subjects and have important implications for NT-proBNP-based strategies for early detection and primary prevention of cardiovascular disease.

Ischaemic nephropathy secondary to atherosclerotic renal artery stenosis: clinical and histopathological correlates

BACKGROUND

Advanced renal artery stenosis (RAS) may cause progressive deterioration in renal function. We correlated the histopathological findings and clinical characteristics in selected patients with atherosclerotic RAS who underwent nephrectomy of their small kidneys for resistant renovascular hypertension.

METHODS

We studied 62 patients who underwent nephrectomy of a small kidney for uncontrolled hypertension between 1990 and 2000.

RESULTS

The mean patient age was 65.4 ± 9.6 years; 28 (45%) were men. Significant tubulointerstitial atrophy with relative glomerular sparing was the predominant pattern of injury in 44 (71%) patients. In 14 (23%) patients, diffuse global glomerulosclerosis was present. The severity of tubulointerstitial atrophy and the extent of glomerulosclerosis were both associated with smaller kidney size (P = 0.002). Three patterns of vascular involvement were present: atheroembolic, atherosclerotic and hypertensive vascular changes, which were documented in 39, 98 and 52% of subjects, respectively. The presence and severity of these vascular changes positively correlated with both atherosclerotic risk factors, such as hypertension, dyslipidaemia and renal insufficiency, and cardiovascular morbidity, including abdominal aortic aneurysm and myocardial infarction. Patients on statin therapy were noted to have less evidence of renal fibrosis as measured by transforming growth factor-beta staining (P = 0.003).

CONCLUSION

The severity of renal histopathological findings in patients who underwent nephrectomy for resistant hypertension correlated with an increased prevalence of cardiovascular disease, a greater degree of renal dysfunction and more severe dyslipidaemia. Statin therapy may affect development of intra-renal injury by slowing the progression of fibrosis.

Computed tomographic coronary artery calcium assessment for evaluating chest pain in the emergency department: long-term outcome of a prospective blind study

OBJECTIVE

To determine the long-term outcome of computed tomographic (CT) quantification of coronary artery calcium (CAC) used as a triage tool for patients presenting with chest pain to an emergency department (ED).

PATIENTS AND METHODS

Patients (men aged 30-62 years and women aged 30-65 years) with chest pain and low-to-moderate probability of coronary artery disease underwent both conventional ED chest pain evaluation and CT CAC assessment prospectively. Patients' physicians were blinded to the CAC results. The results of the conventional evaluation were compared with CAC findings on CT, and the long-term outcome in patients undergoing CT CAC assessment was established. Primary end points (acute coronary syndrome, death, fatal or nonfatal non-ST-segment elevation myocardial infarction, fatal or nonfatal ST-segment elevation myocardial infarction) and secondary outcomes (coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, coronary stenting, or a combination thereof) were obtained when the patient was dismissed from the ED or hospital and then at 30 days, 1 year, and 5 years.

RESULTS

Of the 263 study patients, 133 (51%) had a CAC score of zero. This absence of CAC correlated strongly with the likelihood of noncardiac chest pain. Among 133 patients with a CAC score of zero, only 1 (<1%) had cardiac chest pain. Conversely, of the 31 patients shown to have cardiac chest pain, 30 (97%) had evidence of CAC on CT. When a CAC cutoff score of 36 was used, as suggested by receiver operating characteristic analysis, sensitivity was 90%; specificity, 85%; positive predictive value, 44%; and negative predictive value, 99%. During long-term follow-up, patients without CAC experienced no cardiac events at 30 days, 1 year, and 5 years.

CONCLUSION

Findings suggest that CT CAC assessment is a powerful adjunct in chest pain evaluation for the population at low-to-intermediate risk. Absent or minimal CAC in this population makes cardiac chest pain extremely unlikely. The absence of CAC suggests an excellent long-term (5-year) prognosis, with no primary or secondary cardiac outcomes occurring in study patients at 5-year follow-up.

Comparison of office, ambulatory, and home blood pressure antihypertensive response to atenolol and hydrochlorthiazide

Office, home, and ambulatory blood pressure (BP) demonstrate variable associations with outcomes. The authors sought to compare office BP (OBP), home BP (HBP), and ambulatory BP (ABP) for measuring responses to hydrochlorothiazide (HCTZ), atenolol, and their combination. After completing washout, eligible patients were randomized to atenolol 50 mg or HCTZ 12.5 mg daily. Doses were doubled after 3 weeks and the alternate drug was added after 6 weeks if BP was >120/70 mm Hg (chosen to allow maximum opportunity to assess genetic associations with dual BP therapy in the parent study). OBP (in triplicate), HBP (twice daily for 5 days), and 24-hour ABP were measured at baseline, after monotherapy, and after combination therapy. BP responses were compared between OBP, HBP, and ABP for each monotherapy and combination therapy. In 418 patients, OBP overestimated BP response compared with HBP, with an average 4.6 mm Hg greater reduction in systolic BP (P<.0001) and 2.1 mm Hg greater reduction in diastolic BP (P<.0001) across all therapies. Results were similar for atenolol and HCTZ monotherapy. ABP response was more highly correlated with HBP response (r=0.58) than with OBP response (r=0.47; P=.04). In the context of a randomized clinical trial, the authors have identified significant differences in HBP, OBP, and ABP methods of measuring BP response to atenolol and HCTZ monotherapy.

Genetic control of the alternative pathway of complement in humans and age-related macular degeneration

Activation of the alternative pathway of complement is implicated in common neurodegenerative diseases including age-related macular degeneration (AMD). We explored the impact of common variation in genes encoding proteins of the alternative pathway on complement activation in human blood and in AMD. Genetic variation across the genes encoding complement factor H (CFH), factor B (CFB) and component 3 (C3) was determined. The influence of common haplotypes defining transcriptional and translational units on complement activation in blood was determined in a quantitative genomic association study. Individual haplotypes in CFH and CFB were associated with distinct and novel effects on plasma levels of precursors, regulators and activation products of the alternative pathway of complement in human blood. Further, genetic variation in CFH thought to influence cell surface regulation of complement did not alter plasma complement levels in human blood. Plasma markers of chronic activation (split-products Ba and C3d) and an activating enzyme (factor D) were elevated in AMD subjects. Most of the elevation in AMD was accounted for by the genetic variation controlling complement activation in human blood. Activation of the alternative pathway of complement in blood is under genetic control and increases with age. The genetic variation associated with increased activation of complement in human blood also increased the risk of AMD. Our data are consistent with a disease model in which genetic variation in the complement system increases the risk of AMD by a combination of systemic complement activation and abnormal regulation of complement activation in local tissues.

Sex and ethnic differences in 47 candidate proteomic markers of cardiovascular disease: the Mayo Clinic proteomic markers of arteriosclerosis study

BACKGROUND

Cardiovascular disease (CVD) susceptibility differs between men and women and varies with ethnicity. This variability is not entirely explained by conventional CVD risk factors. We examined differences in circulating levels of 47 novel protein markers of CVD in 2561 men and women of African-American (AA) and non-Hispanic White (NHW) ethnicity, enrolled at geographically distinct sites.

METHODOLOGY/PRINCIPAL FINDINGS

Participants (1,324 AAs, mean age 63.5 y, 71% women; 1,237 NHWs, mean age 58.9 y, 57% women) belonged to sibships ascertained on the basis of hypertension. Solid-phase immunoassays and immunoturbidometric, clot-based, chromogenic, and electrophoretic assays were used to measure the 47 protein markers in plasma or serum. Marker levels were log transformed and outliers were adjusted to within 4 SD. To identify markers independently associated with sex or ethnicity, we employed multivariable regression analyses that adjusted for conventional risk factors, prior history of CVD, medication use and lifestyle factors (physical activity, alcohol consumption and education). Generalized estimating equations were used to correct for intrafamilial correlations. After adjustment for the above covariates, female sex was associated with higher levels of 29 markers and lower levels of 6 markers. Female sex was independently associated with higher levels of several inflammatory markers as well as lipoproteins, adipokines, natriuretic peptides, vasoconstrictor peptides and markers of calcification and thrombosis. AA ethnicity was associated with higher levels of 19 markers and lower levels of 6 markers, including higher levels of several inflammatory makers, higher leptin and lower adiponectin levels, lower levels of vasodilator-natriuretic peptides, higher levels of vasoconstrictor-antidiuretic peptides and markers of calcification and thrombosis.

CONCLUSIONS/SIGNIFICANCE

Plasma levels of several novel protein markers of CVD differ significantly in the context of sex and ethnicity. These results have implications for individualized CVD risk assessment.

Risk factors and underlying mechanisms for venous stasis syndrome: a population-based case-control study

Venous stasis syndrome may complicate deep vein thrombosis (DVT; i.e. post-phlebitic syndrome), but, in most cases, venous stasis syndrome is not post-phlebitic. The objective of this study was to determine the risk factors (including prior DVT) for venous stasis syndrome, and to assess venous outflow obstruction and venous valvular incompetence as possible mechanisms for venous stasis syndrome. This was a case-control study nested within a population-based inception cohort. The study population consisted of 232 Olmsted County, MN residents with a first lifetime venous thromboembolism (VTE) and 133 residents without VTE. Measurements included a questionnaire and physical examination for venous stasis syndrome; strain gauge outflow plethysmography, venous continuous wave Doppler ultrasonography and passive venous drainage and refill testing for venous outflow obstruction and venous valvular incompetence. Altogether, 161 (44%), 43 (12%), and 136 (38%) subjects respectively, had venous stasis syndrome, venous outflow obstruction and venous valvular incompetence. Independent risk factors for venous stasis syndrome included increasing patient age and body mass index (BMI), prior DVT, longer time interval since DVT, and varicose veins. Both venous outflow obstruction (p = 0.003) and venous valvular incompetence (p < 0.0001) were strongly associated with venous stasis syndrome. Increasing age and prior DVT were significantly associated with venous outflow obstruction, while prior DVT, varicose veins and venous stasis syndrome diagnosed prior to the incident DVT were significantly associated with venous valvular incompetence. The risks of venous outflow obstruction, venous valvular incompetence and venous stasis syndrome were higher with left leg DVT. In conclusion, increasing patient age and BMI, prior DVT (particularly left leg DVT), longer time interval since DVT and varicose veins are independent risk factors for venous stasis syndrome. Venous stasis syndrome related to DVT is due to venous outflow obstruction and venous valvular incompetence, while venous stasis syndrome related to older age and to varicose veins is due to venous outflow obstruction and to venous valvular incompetence, respectively.