Title: Delayed Hyper-Enhancement Magnetic Resonance Imaging Provides Incremental Diagnostic and Prognostic Utility in Suspected Cardiac Amyloidosis
Topic: Noninvasive Cardiology
Date Posted: 1/28/2010
Author(s): Austin BA, Wilson Tang WH, Rodriguez ER, et al.
Citation: JACC Cardiovasc Imaging 2009;2:1369-1377.
Clinical Trial: No
Study Question: What is the diagnostic accuracy and prognostic value of delayed hyper-enhancement on cardiac magnetic resonance imaging (DHE-CMR) compared to standard electrocardiographic (ECG) and echocardiographic parameters in patients with suspected cardiac amyloid?
Methods: Routine ECG, echocardiography for Doppler diastolic parameters, and DHE-CMR were available in 47 patients with suspected cardiac amyloid, all of whom underwent either endomyocardial (n = 38) or extracardiac biopsy. Diastolic parameters included deceleration time, E/E' ratio, and diastolic grade. Cardiac amyloid was considered present if CMR revealed diffuse DHE of the subendocardium. The endpoint of all-cause mortality was tabulated.
Results: Average patient age was 62 years and 70% were male. Biopsy was positive for amyloid in 25 and negative in 22 patients. New York Heart Association class >II was present in 55% of biopsy-negative and 56% of biopsy-positive patients. Low voltage on the ECG (Carroll criteria) was noted in 55% of biopsy-negative and 60% of biopsy-positive patients. A speckled appearance on echocardiography was noted in no biopsy-negative patients and in four (16%) biopsy-positive patients. Ventricular septal thickness averaged 1.3 cm (1.1-1.6) in biopsy-negative and 1.7 cm (1.4-2) in biopsy-positive patients. A deceleration time ≤150 ms was noted in six biopsy-negative patients (27%) and eight (32%) biopsy-positive patients. Grade II or worse diastolic dysfunction was noted in nine biopsy-negative patients (41%) and 13 (50%) biopsy-positive patients. DHE-CMR was characteristic of cardiac amyloid in three biopsy-negative patients (14%) versus 19 (76%) biopsy-positive patients (p < 0.0001). Sensitivity, specificity, positive, and negative predictive values for low-voltage ECG were 76%, 48%, 54%, and 71%, and 35%, 62%, 43%, and 54% for deceleration time ≤150 ms. DHE-CMR had corresponding values of 88%, 90%, 88%, and 90%. Of the preceding parameters (plus others), only DHE-CMR was predictive of cardiac amyloid on multivariable analysis. At 1 year following biopsy, there were nine (19%) deaths in biopsy-positive patients, including seven who were DHE-CMR positive. On multivariable analysis, only DHE-CMR was predictive of mortality.
Conclusions: DHE-CMR is more accurate than echocardiographic or ECG parameters for diagnosing cardiac amyloid, and a positive DHE-CMR confers a worse 1-year prognosis than does advanced diastolic dysfunction on Doppler.
Perspective: Several previous studies have suggested a characteristic pattern on gadolinium-enhanced CMR to be diagnostic of cardiac amyloid. This study compares this finding to traditional ECG and echocardiographic parameters of abnormal diastolic function, and suggests that the accuracy of CMR exceeds these more traditional and widespread techniques. Previous studies have suggested that advanced diastolic dysfunction confers an adverse prognosis in patients with documented cardiac amyloid. It should be noted that virtually all studies evaluating echocardiographic and other parameters in cardiac amyloid are relatively limited in scope. This study suggests that a typical pattern of diffuse hyper-enhancement on CMR is not only more accurate for the diagnosis of cardiac amyloid, but has independent adverse prognostic implications. William F. Armstrong, M.D., F.A.C.C.
Title: Effects of the DASH Diet Alone and in Combination With Exercise and Weight Loss on Blood Pressure and Cardiovascular Biomarkers in Men and Women With High Blood Pressure: The ENCORE Study
Topic: Prevention/Vascular
Date Posted: 1/28/2010
Author(s): Blumenthal JA, Babyak MA, Hinderliter A, et al.
Citation: Arch Intern Med 2010;170:126-135.
Clinical Trial: No
Study Question: Does the DASH diet lower blood pressure and alter cardiovascular risk biomarkers among free-living adults?
Methods: This was a randomized controlled trial, which compared the DASH diet alone or in combination with a weight management program to usual diet controls. Participants were overweight or obese (body mass index 25-40 kg/m2) with prehypertension or stage one hypertension (130-149 mm Hg systolic blood pressure and/or 85-99 mm Hg diastolic blood pressure). Participants in the DASH diet alone or the usual diet groups consumed isocaloric meals with the goal of maintenance of their baseline weight. Those in the DASH plus weight management group consumed meals at a 500-caloric deficit. Exercise for this group consisted of three classes per week. The primary outcome of interest was clinic blood pressure and ambulatory blood pressure. Secondary outcomes included pulse wave velocity, flow-mediated dilation, baroreflex sensitivity, and left ventricular mass.
Results: Among the 144 participants, those randomized to the DASH diet plus weight management had the greatest reduction in clinic blood pressure (16.1/9.9 mm Hg), followed by the DASH diet alone (11.2/7.5 mm Hg), with the usual diet controls having the least change in blood pressure (3.4/3.8 mm Hg). Ambulatory blood pressure measures were similar. Greater improvements in pulse wave velocity, baroreflex sensitivity, and left ventricular mass were observed in participants randomized to the DASH diet and weight management, as compared to those randomized to the DASH diet alone.
Conclusions: The investigators concluded that for overweight or obese patients with prehypertension or stage one hypertension, the DASH diet with weight management resulted in significant reductions in blood pressure and improved vascular and autonomic tone.
Perspective: This study demonstrates the significance of combining dietary changes with increased physical activity. Incorporation of exercise to the DASH diet resulted in significant blood pressure reduction and improved vascular function. Elizabeth A. Jackson, M.D., F.A.C.C.