Myung-A Kim

Velocity Vector Imaging in the Measurement of Left Ventricular Twist Mechanics: Head-to-Head One Way Comparison Between Speckle Tracking Echocardiography and Velocity Vector Imaging

BACKGROUND Velocity vector imaging (VVI) is based on myocardial feature tracking, which incorporates speckle and endocardial border tracking and allows myocardial strains, strain rates, and velocities to be quantified. However, the accuracies of VVI-derived left ventricular rotation-associated values have not been validated, and the aim of this study was thus to perform a head-to-head comparison of twist-related values determined by VVI and speckle-tracking echocardiography (STE). METHODS Thirty-five patients with a wide spectrum of cardiac pathologies and 19 healthy subjects (a total of 54 subjects) were enrolled. Apical and basal short-axis images were obtained using GE Vivid 7 scanners at frame rates of 80 to 100 frames/s. Left ventricular rotation-related parameters were first obtained using EchoPAC version 7.0.1. For comparison purposes, the same basal and apical short-axis images were converted into uncompressed Digital Imaging and Communications in Medicine format and subsequently analyzed using Syngo version 3.0, which uses a VVI tracking algorithm. RESULTS Basal and apical peak rotation and peak twist determined using STE and VVI were well correlated (r = 0.80, P < .001, r = 0.87, P < .001, and r = 0.90, P < .001, respectively). With regard to rotation velocities, peak rotation and derotation velocities were moderately correlated at the basal (r = 0.70, P < .001, and r = 0.72, P < .001, respectively) and apical (r = 0.66, P < .001, and r = 0.51, P < .001, respectively) levels. Furthermore, twist and untwist velocities were moderately correlated between the two methods. However, the timings of peak rotation and derotation velocities and twist and untwist velocities were only weakly correlated at the basal and apical levels. CONCLUSIONS VVI is a feasible modality for assessing twist-related parameters. Although VVI agreed well with STE for most of the rotation-related parameters, poor concordance was found between the two methods for a few parameters. It is hypothesized that this discrepancy originates from the different tracking algorithms used. The findings indicate that caution should be exercised when interpreting or comparing twist-related parameters obtained using different echocardiographic devices with proprietary image analyzers.

Effects of ACE2 Inhibition in the Post-Myocardial Infarction Heart

BACKGROUND There is evidence that angiotensin-converting enzyme 2 (ACE2) is cardioprotective. To assess this in the post-myocardial infarction (MI) heart, we treated adult male Sprague-Dawley rats with either placebo (PL) or C16, a selective ACE2 inhibitor, after permanent coronary artery ligation or sham operation. METHODS AND RESULTS Coronary artery ligation resulting in MI between 25% to 50% of the left ventricular (LV) circumference caused substantial cardiac remodeling. Daily C16 administration from postoperative days 2 to 28 at a dose that inhibited myocardial ACE2 activity was associated with a significant increase in MI size and reduction in LV % fractional shortening. Treatment with C16 did not significantly affect post-MI increases in LV end-diastolic dimension but did inhibit increases in wall thickness and fibrosis in non-infarcted LV. On postoperative day 7, C16 had no significant effect on the increased level of apoptosis in the infarct and border zones nor did it significantly affect capillary density surrounding the MI. It did, however, significantly reduce the number of c-kit(+) cells in the border region. CONCLUSIONS These findings support the notion that ACE2 exerts cardioprotective effects by preserving jeopardized cardiomyocytes in the border zone. The reduction in hypertrophy and fibrosis with C16, however, suggests that ACE2 activity has diverse effects on post-MI remodeling.

Behçet's Disease as a Frequently Unrecognized Cause of Aortic Regurgitation: Suggestive and Misleading Echocardiography Findings

BACKGROUND Behçets disease (BD) is a systemic vasculitis that can be a possible cause of aortic regurgitation (AR). When aortic valve replacement is performed in patients with BD, unless preoperative immunosuppressive therapy and special operative techniques are used, the postoperative course is usually complicated by valve dehiscence, necessitating another operation. The preoperative diagnosis of BD is challenging because of its protean manifestations, but an early diagnosis is associated with a more favorable prognosis. METHODS Between 1990 and 2008, 15 patients with final diagnoses of BD underwent aortic valve replacement. Medical records and echocardiographic findings were retrospectively analyzed. RESULTS Of the 15 patients, only 2 were diagnosed as having BD prior to first operation. Twelve underwent repeat open-heart surgery because of valve dehiscence, and 6 of these 12 patients eventually died. In 5 patients with available echocardiographic findings of native valve morphology, echocardiography demonstrated characteristic aneurysmal changes and redundant coronary cusp motion in 4 patients. Vegetation-like mobile lesions and echo-free spaces mimicking abscess pockets led to misdiagnoses of infective endocarditis in 7 patients at least once during their clinical courses. Furthermore, complete atrioventricular block requiring permanent pacemaker insertion developed in 5 patients, especially those with echo-free spaces in the periannular area. CONCLUSIONS Dismal prognoses are almost inevitable unless etiologic diagnoses are made prior to surgery in patients with BD and AR. It is important to diagnose BD preoperatively, and the diagnostic importance of echocardiographic findings should be kept in mind when evaluating patients with AR.

The Advantages of On-line Transesophageal Echocardiography Guide During Percutaneous Balloon Mitral Valvuloplasty***

The purpose of this study was to evaluate the potential advantages of on-line transesophageal echocardiography during percutaneous balloon mitral valvuloplasty (PBMV). One hundred thirty-four consecutive patients who underwent PBMV were included in this study. Group 1 included 64 patients who underwent PBMV under fluoroscopy guide only, and group 2 included 70 patients who underwent PBMV under on-line transesophageal echocardiography guide. Inoue balloons were used in all cases. The mitral valve area after valvuloplasty was comparable between the 2 groups. The procedure time was significantly shorter in group 2 (99 +/- 48 min vs 64 +/- 22 min, P <.0001 ), and the average fluoroscopy time was shorter in group 2 without statistical significance (30 +/- 17 min vs 19 +/- 15 min, P =.25 ). Five (7.8%) patients in group 1 and 2 (2.8%) patients in group 2 underwent surgery because of procedure-related complications. The limitation of this study was the learning curve of the operator, because the 2 groups were treated serially. In conclusion, transesophageal echocardiography can be used effectively during balloon mitral valvuloplasty, and it may help to reduce the rate of complications resulting from trans-septal catheterization and balloon valvuloplasty and to reduce procedure time and fluoroscopy time.

The association between arterial stiffness and left ventricular filling pressure in an apparently healthy Korean population

BackgroundThe aim of this study is to investigate the association between arterial stiffness and left ventricular filling pressure in an apparently healthy Korean population.MethodsA total of 115 healthy subjects without known cardiovascular risk factors or overt heart disease who underwent both transthoracic echocardiography and brachial-ankle pulse wave velocity (baPWV) measurement at the same day during their routine check-ups were analyzed.ResultsThe mean age of study subjects was 52.8 ± 8.4 years, and 78 (67.8%) were men. The mean baPWV value was 1,325 ± 185 cm/s. Study subjects were divided into 3 groups according to E/E’ value: subjects with E/E’ < 8, 8–12.9 and E/E’ ≥ 13. As E/E’ increased, baPWV value increased gradually: baPWV in subjects with E/E’ < 8, E/E’ 8–12.9 and E/E’ ≥ 13, were 1,261 ± 163, 1,345 ± 169, 1,569 ± 232 cm/s, respectively (p < 0.001). In multiple linear regression analyses, baPWV was significantly associated with E/E’ (β = 0.371, p < 0.001) after controlling confounders including age, sex and body mass index. In receiver-operating characteristic (ROC) curve analysis, the sensitivity and specificity for detection of E/E’ ≥ 10 were 78.6% and 59.8%, respectively with mean baPWV of 1,282 cm/s as the cut off value. The discriminatory capacity for predicting E/E’ ≥ 10 was improved from an area under the ROC curve of 0.646 with age alone to 0.734 when baPWV was added (p < 0.001).ConclusionsThere is a significant association between baPWV and E/E’ in an apparently healthy Korean population. BaPWV is useful as a simple and non-invasive method for early detection of increased LV filling pressure among these people.

Incremental Prognostic Value of Brachial-Ankle Pulse Wave Velocity to Single-Photon Emission Computed Tomography in Patients with Suspected Coronary Artery Disease.

AIM Arterial stiffness assessed by brachial-ankle pulse wave velocity (baPWV) is predictive of cardiovascular events. This study was designed to investigate whether baPWV has an additional prognostic value to single-photon emission computed tomography (SPECT) in patients with suspected coronary artery disease (CAD). METHODS A total of 350 subjects (age, 66.2 ± 10.5 years, 53.4% male) with suspected CAD undergoing myocardial SPECT and baPWV within 30 days were retrospectively analyzed. Cardiovascular events, including cardiovascular death, acute coronary syndrome and ischemic stroke, were assessed. Both fixed and reversible perfusion defects on SPECT were considered abnormal myocardial perfusion imaging (MPI) findings. RESULTS During the median follow-up period of 441 days (interquartile range 169-719 days), cardiovascular events occurred in 21 patients (6.0%). In multivariable Cox regression analysis, abnormal MPI [hazard ratio (HR), 2.67; 95% confidence interval (CI), 1.21-10.37; p=0.024] and high baPWV (≥ 1,790 cm/s) (HR, 2.03; 95% CI, 1.08-6.38; p=0.007) were independent predictors of clinical events even after adjusting for possible confounders. Also, high baPWV had an incremental prognostic value to traditional risk factors and abnormal MPI in predicting cardiovascular events (overall Chi-square, from 24.08 to 27.42; p ＜ 0.001). Kaplan-Meier survival curves stratified by baPWV and MPI proved significantly improved prediction of cardiovascular events (log-rank p=0.001). CONCLUSIONS baPWV has an incremental prognostic value to traditional risk factors and MPI. Therefore, baPWV can be used to identify subjects at higher risk of cardiovascular events in patients undergoing SPECT.

Impact of acute exercise on brachial artery flow-mediated dilatation in young healthy people

BackgroundAlthough chronic effects of exercise on endothelial function are established, the impact of acute exercise on flow-mediated dilatation (FMD) of brachial artery has not been elucidated yet.MethodsEighty-six young healthy volunteers were prospectively enrolled from January 2011 to December 2011. The subjects completed FMD tests at rest and immediately after treadmill exercise test. Primary outcome was the impact of acute exercise on FMD, measured by the difference of FMD before and after exercise. Secondary outcomes were the relationship of gender and exercise habit with FMD.ResultsSeventy-four subjects who met the eligibility criteria were included for analysis. Thirty-five (47.3%) were male, and the mean age was 22.7±2.7 years. FMD was reduced after exercise (8.98±4.69 to 7.51±4.03%; P=0.017) and the reduction was found in female group (10.36±5.26 to 7.62±3.71%; P=0.002) but not in male group. Post-exercise FMD was significantly impaired in subjects who did not exercise regularly (6.92±3.13% versus 8.95±5.33%; P=0.003). The decrease of FMD after exercise was greater in female group (−2.75±5.28% versus 0.27±3.24%; P=0.003) and was associated with exercise habit (β=2.532; P=0.027).ConclusionsIn healthy young subjects, FMD was reduced after a bout of acute exercise. The impact of acute exercise showed significant differences according to gender and exercise habit. FMD impairment after acute exercise was observed in females and subjects without regular exercise.

The Effect of Aspirin on C-Reactive Protein in Hypertensive Patients

High level of C-reactive protein (CRP), most popular inflammatory marker, increases the risk of thrombotic cardiovascular events. Aspirin, which has both anti-inflammatory and anti-thrombotic effects, has the potential to influence CRP release. Several studies have been reported investigating clinical effects of aspirin on CRP levels. Some studies have reported aspirin reduced CRP levels, but other studies did not. This study was designed to assess the effect of low-dose aspirin on CRP levels in controlled hypertensive patients who had low inflammatory burden. Two hundred twenty-five patients with controlled hypertension were randomly divided into two groups; aspirin group (n = 122, 100 mg of aspirin) and the control group (n = 134). Patients with a CRP level >1 mg/dL (10 mg/L) were excluded because these high levels suggest infection. C-reactive protein level and lipid profiles were measured before therapy and 3 months after therapy. There were no differences in baseline clinical characteristics between the two groups. Low-dose aspirin showed no significant influence on CRP levels over 3 months (from 0.10 ± 0.0099 to 0.12 ± 0.0097 mg/dL, p = 0.12). Statin therapy did not influence CRP levels. Aspirin-resistance also had no influence on CRP levels. We conclude that low-dose aspirin has no significant effect on decreasing CRP levels in the patients with controlled hypertension which had low inflammatory burden. The anti-inflammatory mechanism may not play an important role in the cardioprotective effect of aspirin in the population with low inflammatory burden such as controlled hypertensive patients.

The Association of Brachial-Ankle Pulse Wave Velocity with Coronary Artery Disease Evaluated by Coronary Computed Tomography Angiography

The aim of this study was to investigate whether brachial-ankle pulse wave velocity (baPWV) is associated with the severity of coronary artery disease (CAD) assessed by coronary computed tomography angiography (CCTA), and to evaluate baPWV as a predictor of obstructive CAD on CCTA. A total of 470 patients who underwent both baPWV and CCTA were included. We evaluated stenosis degree and plaque characteristics on CCTA. To estimate the severity of CAD, we calculated the number of segment with plaque (segment involvement score; SIS), stenosis degree-weighted plaque score (segment stenosis score; SSS), and coronary artery calcium score (CACS). The mean baPWV was 1,485 ± 315 cm/s (range, 935-3,175 cm/s). Non-obstructive (stenosis < 50%) and obstructive (stenosis ≥ 50%) CAD was found in 129 patients (27.4%) and 144 (30.6%), respectively. baPWV in patients with obstructive CAD was higher than that of patients with non-obstructive (1,680 ± 396 cm/s versus 1,477 ± 244 cm/s, P < 0.001) or no CAD (1,680 ± 396 cm/s versus ± 196 1,389 cm/s, P < 0.001). baPWV showed significant correlation with SSS (r = 0.429, P < 0.001), SIS (r = 0.395, P < 0.001), CACS (r 0.346, P < 0.001), and the number of segment with non-calcified plaque (r 0.092, P = 0.047), mixed plaque (r = 0.267, P < 0.001), and calcified plaque (r = 0.348, P < 0.001), respectively. The optimal baPWV cut-off value for the detection of obstructive CAD was 1,547 cm/s. baPWV ≥ 1,547 cm/s was independent predictor for the obstructive CAD. In conclusion, baPWV is well correlated with the severity of CAD evaluated by CCTA. baPWV has the potential to predict severity of coronary artery atherosclerosis.

The effects of metabolic syndrome and its components on arterial stiffness in relation to gender

OBJECTIVES The influence of gender-dependent metabolic risk factors on arterial stiffness has not been fully determined. This study was performed to investigate the relationship between components of metabolic syndrome and brachial-ankle pulse wave velocity (baPWV) according to gender. METHODS A total of 537 subjects (54.4±7.5 years and 70.6% men) who underwent baPWV measurement during routine check-ups were analyzed. RESULTS BaPWV was 1363±229cm/s in men and 1387±269cm/s in women (p=0.313). The prevalence of metabolic syndrome was not different according to gender (23% in men versus 27% in women, p=0.335). In multiple linear regression analyses, after adjustment for age, baPWV was significantly associated with systolic and diastolic blood pressures, fasting glucose, and triglyceride in both genders. Waist circumference was associated with baPWV in women but not in men. High-density lipoprotein levels were not associated with baPWV in either gender. Subjects with metabolic syndrome had a higher baPWV than those without metabolic syndrome for women aged <55 years, but not for all men and women aged ≥55 years. As the number of the components of metabolic syndrome increased, baPWV increased proportionally in both genders. However, this correlation was more strong in women than that in men (β=0.408 versus β=0.146 after adjustment for age). CONCLUSION In middle-aged Koreans, women showed stronger associations between each component of metabolic syndrome and baPWV than men. The association of each component of metabolic syndrome to arterial stiffness may differ between men and women.