Laura A. Tuttle

Reproducibility of masked hypertension among adults 30 years or older.

ObjectiveMasked hypertension (MH) refers to nonelevated office blood pressure (BP) with elevated out-of-office BP, but its reproducibility has not been conclusively established. We examined 1-week reproducibility of MH by home BP monitoring (HBPM) and ambulatory BP monitoring (ABPM). MethodsWe recruited 420 adults not on BP-lowering medication, with recent clinic BP between 120/80 and 149/95 mmHg. For main comparisons, participants with office average less than 140/90 mmHg were considered to have MH if awake ABPM average was 135/85 mmHg or higher; they were considered to have MH by HBPM if the average was 135/85 mmHg or higher. Percentage agreements were quantified in terms of &kgr;. We also examined the prevalence of MH, defined as office average less than 140/90 mmHg, with a 24-h ABPM average of 130/80 mmHg or higher. We carried out sensitivity analyses using different threshold BP levels for ABPM–office pairings and HBPM–office pairings for defining MH. ResultsPrevalence rates of MH based on office–awake ABPM pairings were 44 and 43%, with an agreement of 71% (&kgr;=0.40; 95% confidence interval 0.31–0.49). MH was less prevalent (15 and 17%) using HBPM–office pairings, with agreement of 82% (&kgr;=0.30; 95% confidence interval 0.16–0.44), and more prevalent when considering the 24-h average (50 and 48%). MH was also less prevalent when more stringent diagnostic criteria were applied. Office–HBPM pairings and office–awake ABPM pairings had fair agreement on MH classification on both occasions, with &kgr;-values of 0.36 and 0.30. ConclusionMH has fair short-term reproducibility, providing further evidence that for some people, out-of-office BP is systematically higher than that measured in the office setting.

Levels of Office Blood Pressure and Their Operating Characteristics for Detecting Masked Hypertension Based on Ambulatory Blood Pressure Monitoring

BACKGROUND Masked hypertension (MH)--nonelevated office blood pressure (BP) with elevated out-of-office BP average--conveys cardiovascular risk similar to or approaching sustained hypertension, making its detection of potential clinical importance. However, it may not be feasible or cost-effective to perform ambulatory BP monitoring (ABPM) on all patients with a nonelevated office BP. There likely exists a level of office BP below which ABPM is not warranted because the probability of MH is low. METHODS We analyzed data from 294 adults aged ≥ 30 years not on BP-lowering medication with office BP <140/90 mm Hg, all of whom underwent 24-hour ABPM. We calculated sensitivity, false-positive rate, and likelihood ratios (LRs) for the range of office BP cutoffs from 110 to 138 mm Hg systolic and from 68 to 88 mm Hg diastolic for detecting MH. RESULTS The systolic BP cutoff with the highest +LR for detecting MH (1.8) was 120 mm Hg, and the diastolic cutoff with the highest +LR (2.4) was 82 mm Hg. However, the systolic level of 120 mm Hg had a false-positive rate of 42%, and the diastolic level of 82 mm Hg had a sensitivity of only 39%. CONCLUSIONS The cutoff of office BP with the best overall operating characteristics for diagnosing MH is approximately 120/82 mm Hg. However, this cutoff may have an unacceptably high false-positive rate. Clinical risk tools to identify patients with nonelevated office BP for whom ABPM should be considered will likely need to include factors in addition to office BP.

Whole Breast Ultrasound: Comparison of the Visibility of Suspicious Lesions with Automated Breast Volumetric Scanning Versus Hand-Held Breast Ultrasound

RATIONALE AND OBJECTIVES To assess how well radiologists visualize relevant features of lesions seen with automated breast volumetric scanning (ABVS) in comparison to hand-held breast ultrasound in women going to breast biopsy. MATERIALS AND METHODS Twenty-five subjects were recruited from women who were scheduled to undergo a breast biopsy for at least one Breast Imaging-Reporting and Data System four or five lesion identified in a diagnostic setting. In this institutional review board-approved study, the subjects underwent imaging of the breast(s) of concern using a dedicated system that allowed both hand-held breast ultrasound and ABVS. Five experienced breast radiologists reviewed the 30 lesions in 25 subjects in a reader study. Each reader was asked to specify the lesion type, size, imaging features, Breast Imaging-Reporting and Data System, and suspicion of malignancy and to compare the lesion characteristics of shape and margins between the two modalities. RESULTS Seven (23.3%) masses were malignant and 23 (76.4%) were benign. Across all lesions regardless of size or final pathology, there was no significant difference in sensitivity or specificity (P > .15) between the two modalities. For malignant lesions, the reader visualization confidence scores between the two ultrasound modalities were not significantly different (P > .1). However, analysis for nonmalignant cases showed a statistically significant increase in reader visualization confidence in lesion shape and margins (P < .001). CONCLUSIONS Radiologists showed increased confidence in visualization of benign masses and equal confidence in suspicious masses with ABVS imaging. This information could help decrease the need for additional hand-held imaging after automated whole breast ultrasound.

Development and initial demonstration of a low-dose dedicated fully 3d breast CT system

Based on earlier work demonstrating more complete, 3D cone beam sampling acquisition approaches that additionally facilitate chest wall imaging posterior to an uncompressed breast, a new, clinic-ready, low-dose breast CT system was developed and is undergoing initial clinical validation. The system includes a small focal spot pulsed x-ray source and 30x30cm2 flat panel detector having 3 degrees of freedom of motion, and a radiopaque patient support that facilitates whole-breast and universal anterior chest-wall imaging. Data is acquired with fully-3D trajectories and iteratively reconstructed within minutes of acquisition. Performance characteristics include: sub-200 micron isotropic reconstructed resolution, low-dose (<4.5 mGy) fully-3D scans acquired in ˜1.5 min, clinic throughput of 1patient/11min, and DICOM compatible images. To date, 25 subjects have been successfully scanned. Characterization results and volumetric clinical images are presented including demonstration of routine anterior chest wall imaging and comparison with digital mammography.

Comparison of patients' confidence in office, ambulatory, and home blood pressure measurements as methods of assessing for hypertension.

ObjectiveUncertainty exists when relying on office (clinic) blood pressure (BP) measurements to diagnose hypertension. Home BP monitoring and ambulatory BP monitoring (ABPM) provide measurements that are more strongly associated with cardiovascular disease. The degree to which patients exhibit uncertainty about office BP measurements is unknown, as is whether they would have less uncertainty about other BP measurement methods. We therefore assessed people’s confidence in methods of BP measurement, comparing perceptions about office BP monitoring, home BP monitoring, and ABPM techniques. MethodsWe surveyed adults who were 30 years or older (n=193), all whom had undergone office BP measurements, two sessions of 24-h ABPM, and two 5-day periods of home BP monitoring. Respondents were asked to indicate their level of confidence on a 1 to 9 scale that BP measurements represented their ‘usual’ BP. ResultsRespondents had least confidence that assessments of BP made by office measurements (median 6) represented usual BP and greater confidence that assessments made by home BP monitoring (median 7, P<0.0001 vs. office) and ABPM (median 8, P<0.0001 vs. office) did so. Confidence levels did not vary significantly by BP levels, age, sex, race, or education level. ConclusionThe finding that patients do not have a great deal of confidence in office BP measurements, but have a higher degree of confidence in home BP and ambulatory BP assessment methods may be helpful in guiding strategies to diagnose hypertension and improve antihypertensive medication adherence.

Dedicated Three-dimensional Breast Computed Tomography: Lesion Characteristic Perception by Radiologists

Objectives: To assess radiologist confidence in the characterization of suspicious breast lesions with a dedicated three-dimensional breast computed tomography (DBCT) system in comparison to diagnostic two-dimensional digital mammography (dxDM). Materials and Methods: Twenty women were recruited who were to undergo a breast biopsy for a Breast Imaging-Reporting and Data System (BI-RADS) 4 or 5 lesion evaluated with dxDM in this Institutional Review Board-approved study. The enrolled subjects underwent imaging of the breast(s) of concern using DBCT. Seven radiologists reviewed the cases. Each reader compared DBCT to the dxDM and was asked to specify the lesion type and BI-RADS score for each lesion and modality. They also compared lesion characteristics: Shape for masses or morphology for calcifications; and margins for masses or distribution for calcifications between the modalities using confidence scores (0-100). Results: Twenty-four biopsied lesions were included in this study: 17 (70.8%) masses and 7 (29.2%) calcifications. Eight (33.3%) lesions were malignant, and 16 (66.7%) were benign. Across all lesions, there was no significant difference in the margin/distribution (Δ = −0.99, P = 0.84) and shape/morphology (Δ = −0.10, P = 0.98) visualization confidence scores of DBCT in relation to dxDM. However, analysis by lesion type showed a statistically significant increase in reader shape (Δ =11.34, P = 0.013) and margin (Δ =9.93, P = 0.023) visualization confidence with DBCT versus dxDM for masses and significant decrease in reader morphology (Δ = −29.95, P = 0.001) and distribution (Δ = −28.62, P = 0.002) visualization confidence for calcifications. Conclusion: Reader confidence in the characterization of suspicious masses is significantly improved with DBCT, but reduced for calcifications. Further study is needed to determine whether this technology can be used for breast cancer screening.

Effects of physical activity calorie expenditure (PACE) labeling: study design and baseline sample characteristics

BackgroundObesity and physical inactivity are responsible for more than 365,000 deaths per year and contribute substantially to rising healthcare costs in the US, making clear the need for effective public health interventions. Calorie labeling on menus has been implemented to guide consumer ordering behaviors, but effects on calories purchased has been minimal.MethodsIn this project, we tested the effect of physical activity calorie expenditure (PACE) food labels on actual point-of-decision food purchasing behavior as well as physical activity. Using a two-group interrupted time series cohort study design in three worksite cafeterias, one cafeteria was assigned to the intervention condition, and the other two served as controls. Calories from food purchased in the cafeteria were assessed by photographs of meals (accompanied by notes made on-site) using a standardized calorie database and portion size-estimation protocol. Primary outcomes will be average calories purchased and minutes of moderate to vigorous physical activity (MVPA) by individuals in the cohorts. We will compare pre-post changes in study outcomes between study groups using piecewise generalized linear mixed model regressions (segmented regressions) with a single change point in our interrupted time-series study. The results of this project will provide evidence of the effectiveness of worksite cafeteria menu labeling, which could potentially inform policy intervention approaches.DiscussionLabels that convey information in a more readily understandable manner may be more effective at motivating behavior change. Strengths of this study include its cohort design and its robust data capture methods using food photographs and accelerometry.

Examination of Several Physiological and Psychosocial Factors Potentially Associated With Masked Hypertension Among Low-Risk Adults

The authors examined the association of factors, in addition to prehypertensive office blood pressure (BP) level, that might improve detection of masked hypertension (MH), defined as nonelevated office BP with elevated out‐of‐office BP average, among individuals at otherwise low risk. This sample of 340 untreated adults 30 years and older with average office BP <140/90 mm Hg all had two sets of paired office BP measurements and 24‐hour ambulatory BP monitoring (ABPM) sessions 1 week apart. Other than BP levels, the only factors that were associated (at P<.10) with MH at both sets were male sex (75% vs 66%) and working outside the home (72% vs 59% for the first set and 71% vs 45% for the second set). Adding these variables to BP level in the model did not appreciably improve detection of MH. No demographic, clinical, or psychosocial measures that improved upon prehypertension as a potential predictor of MH in this sample were found.

The Reproducibility of Racial Differences in Ambulatory Blood Pressure Phenotypes and Measurements

BACKGROUND We examined the reproducibility of differences in ambulatory blood pressure (BP) monitoring (ABPM) phenotypes and other parameters (sustained hypertension, masked hypertension, nocturnal hypertension, and nondipping) between African Americans and Whites. METHODS A total of 420 participants untreated for hypertension attended 2 research visits 1 week apart during which traditional office BP averages and ABPM session averages were determined. We computed percent agreement in ABPM phenotypes across the 2 visits stratified by race and associated kappa statistics with 95% confidence intervals. RESULTS Whites on average were older, more likely to be male, and had a higher body mass index. There was no significant difference in sleep quality as defined by sleep diary between the 2 races. There were also no significant differences between races in the proportions of participants with sustained hypertension, sustained normotension, or masked hypertension at either testing session. The prevalence of nocturnal hypertension was 59% vs. 75% (P = 0.012) at session 1 and 59% vs. 73% (P = 0.024) at session 2 for Whites and African Americans, respectively, with moderate reproducibility for both (kappas 0.45 and 0.44). Nocturnal BP nondipping had a prevalence 29% vs. 53% (P < 0.001) at session 1 and 29% vs. 47% (P = 0.004) at session 2 for Whites and African Americans, respectively, with fair reproducibility (kappas 0.28 and 0.29). CONCLUSIONS Our findings support that African Americans indeed exhibit a greater preponderance of abnormal nocturnal BP patterns than Whites. Our work is some of the first to demonstrate that these abnormal patterns are modestly reproducible.

Association of ambulatory blood pressure variability with coronary artery calcium

Blood pressure (BP) variability is associated with progression to clinical atherosclerosis. The evidence is inconclusive if BP variability predicts cardiovascular outcomes in low‐risk populations. The aim of this study was to analyze the association of 24‐hour BP variability with coronary artery calcium (CAC) among a group of individuals without coronary artery disease. The Masked Hypertension Study targeted patients with borderline high BP (120−149 mm Hg systolic and/or 80‐95 mm Hg diastolic). Ambulatory blood pressure monitoring (ABPM) was performed at two time‐points, 8 days apart. CAC was measured at exit visit via cardiac CT and reported as Agatston Score. Weighted standard deviations and average real variability were calculated from ABPM. Of the 322 participants who underwent cardiac CT, 26% (84) had CAC present, 52% (168) were female, and 21% (64) were black. BP variability did not differ by CAC group. In this low cardiovascular risk group, CAC was not associated with 24‐hour ambulatory BP variability.