n-Yuan Chu

Association of Interarm Systolic Blood Pressure Difference with Atherosclerosis and Left Ventricular Hypertrophy

An interarm systolic blood pressure (SBP) difference of 10 mmHg or more have been associated with peripheral artery disease and adverse cardiovascular outcomes. We investigated whether an association exists between this difference and ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), and echocardiographic parameters. A total of 1120 patients were included in the study. The bilateral arm blood pressures were measured simultaneously by an ABI-form device. The values of ABI and baPWV were also obtained from the same device. Clinical data, ABI<0.9, baPWV, echocariographic parameters, and an interarm SBP difference ≥10 mmHg were compared and analyzed. We performed two multivariate forward analyses for determining the factors associated with an interarm SBP difference ≥10 mmHg [model 1: significant variables in univariate analysis except left ventricular mass index (LVMI); model 2: significant variables in univariate analysis except ABI<0.9 and baPWV]. The ABI<0.9 and high baPWV in model 1 and high LVMI in model 2 were independently associated with an interarm SBP difference ≥10 mmHg. Female, hypertension, and high body mass index were also associated with an interarm SBP difference ≥10 mmHg. Our study demonstrated that ABI<0.9, high baPWV, and high LVMI were independently associated with an interarm SBP difference of 10 mmHg or more. Detection of an interarm SBP difference may provide a simple method of detecting patients at increased risk of atherosclerosis and left ventricular hypertrophy.

Global left ventricular longitudinal systolic strain as a major predictor of cardiovascular events in patients with atrial fibrillation

Objective Although global left ventricular longitudinal systolic strain (GLS) is a sensitive measure of left ventricular mechanics, its relationship with adverse cardiovascular (CV) events in atrial fibrillation (AF) has not been evaluated. This study sought to examine the ability of GLS in predicting CV events in AF. Design Observational cohort study. Setting Department of cardiology in a university hospital. Patients 196 persistent AF patients referred for echocardiographic examination. Main outcome measures The risk of GLS measured by index beat method for CV events was assessed by Cox proportional hazards analyses. CV events were defined as CV death, non-fatal stroke and hospitalisation for heart failure. Results There were 19 CV deaths, 12 non-fatal stroke and 28 hospitalisations for heart failure during an average follow-up of 21±10 months. Multivariate analysis showed worsening GLS (HR 1.121; 95% CI 1.023 to 1.228, p=0.014) was independently associated with increased CV events. In direct comparison, GLS outperformed left ventricular ejection fraction (LVEF) and systolic mitral annulus velocity (Sa) in predicting adverse CV events both in univariate and multivariate models (p≤0.043). Besides, the addition of GLS to a Cox model containing chronic heart failure, hypertension, age ≥75 years, diabetes, prior stroke score, estimated glomerular filtration rate, LVEF and Sa provided an additional benefit in the prediction of adverse CV events (p=0.022). Conclusions GLS was a major parameter and stronger than LVEF and Sa in predicting adverse CV events and could offer an additional prognostic benefit over conventional clinical and echocardiographic systolic parameters in AF.

Measuring Left Ventricular Peak Longitudinal Systolic Strain from a Single Beat in Atrial Fibrillation: Validation of the Index Beat Method

BACKGROUND It is traditionally difficult to estimate left ventricular (LV) systolic function in atrial fibrillation (AF). The aim of this study was to validate the use of an index beat, the beat after the nearly equal preceding (RR1) and pre-preceding (RR2) intervals, for the measurement of LV peak longitudinal systolic strain (PLSS). The difference between RR1 and RR2 intervals of the index beat must be <60 msec. LV PLSS measured from the index beat (PLSSindex) was compared with LV PLSS measured from the conventional but time-consuming method of averaging multiple cardiac cycles (PLSSavg). METHODS Ninety-eight patients with persistent or permanent AF and resting ventricular rates ≤ 105 beats/min were prospectively included. LV PLSSindex and LV PLSSavg were obtained from two-dimensional speckle-tracking echocardiography. RESULTS LV PLSSindex had a highly significant correlation with LV PLSSavg (r = 0.970, P < .001). Bland-Altman analysis showed only small bias of 0.01%, and the 95% limits of agreement were +1.64% to -1.62%. Compared with those with lower risk scores of stroke indicated by CHADS(2) scores < 2 or CHA(2)DS(2)-VASc scores < 2, patients with higher risk scores of stroke indicated by CHADS(2) scores ≥ 2 or CHA(2)DS(2)-VASc scores ≥ 2 had lower PLSSavg and PLSSindex (P ≤ .012). CONCLUSIONS LV PLSSindex was a good alternative to LV PLSSavg in patients with AF. Use of the index beat to measure LV longitudinal systolic strain in patients with AF was as accurate as the time-consuming method of averaging multiple cardiac cycles.

Myocardial performance index derived from brachial-ankle pulse wave velocity: a novel and feasible parameter in evaluation of cardiac performance.

BACKGROUND Right brachial pre-ejection period (rbPEP), brachial-ankle pulse wave velocity (baPWV), and right brachial ejection time (rbET) can be automatically determined from an ABI-form device. The aims of this study are to test the applicability of baPWV-derived myocardial performance index (MPI) (defined as the ratio of rbPEP divided by its own s.d. + baPWV divided by its own s.d. to rbET divided by its own s.d.) as an indicator of combined left ventricular (LV) systolic and diastolic functions. METHODS A sum of 215 patients were consecutively included. The rbPEP, baPWV, and rbET were measured using an ABI-form device and LV function was determined by echocardiography. RESULTS After a multivariate analysis, diastolic blood pressure (beta = 0.220, P < 0.001), LV ejection fraction (LVEF) (beta = -0.291, P < 0.001), transmitral E wave velocity (E) (beta = -0.106, P = 0.032), early diastolic mitral annular velocity (Ea) (beta = -0.142, P = 0.009), and ET obtained by tissue Doppler echocardiography (beta = -0.397, P < 0.001) were the major determinants of baPWV-derived MPI. The area under the curve for rbPEP, baPWV, rbET, rbPEP/rbET, and baPWV-derived MPI in prediction of Ea <8 cm/s, E/Ea >10, or LVEF <50% were 0.69, 0.76, 0.67, 0.73, and 0.83, respectively. CONCLUSIONS BaPWV-derived MPI had a significant correlation with echocardiographic LV diastolic and systolic function. It may be a novel and feasible indicator in assessment of global LV function.

Cardiovascular events in patients with atherothrombotic disease: a population-based longitudinal study in Taiwan.

Background Atherothrombotic diseases including cerebrovascular disease (CVD), coronary artery disease (CAD), and peripheral arterial disease (PAD), contribute to the major causes of death in the world. Although several studies showed the association between polyvascular disease and poor cardiovascular (CV) outcomes in Asian population, there was no large-scale study to validate this relationship in this population. Methods and Results This retrospective cohort study included patients with a diagnosis of CVD, CAD, or PAD from the database contained in the Taiwan National Health Insurance Bureau during 2001–2004. A total of 19954 patients were enrolled in this study. The atherothrombotic disease score was defined according to the number of atherothrombotic disease. The study endpoints included acute coronary syndrome (ACS), all strokes, vascular procedures, in hospital mortality, and so on. The event rate of ischemic stroke (18.2%) was higher than that of acute myocardial infarction (5.7%) in our patients (P = 0.0006). In the multivariate Cox regression analyses, the adjusted hazard ratios (HRs) of each increment of atherothrombotic disease score in predicting ACS, all strokes, vascular procedures, and in hospital mortality were 1.41, 1.66, 1.30, and 1.14, respectively (P≦0.0169). Conclusions This large population-based longitudinal study in patients with atherothrombotic disease demonstrated the risk of subsequent ischemic stroke was higher than that of subsequent AMI. In addition, the subsequent adverse CV events including ACS, all stroke, vascular procedures, and in hospital mortality were progressively increased as the increase of atherothrombotic disease score.

Impact of systolic time intervals on the relationship between arterial stiffness and left ventricular hypertrophy

OBJECTIVES Arterial stiffness is correlated with left ventricular hypertrophy (LVH) and is susceptible to left ventricular performance. Therefore, if left ventricular systolic function is unknown, the relationship between arterial stiffness and LVH is controversial. This study was to assess the impact of the ratio of brachial pre-ejection period (bPEP) to brachial ejection time (bET), a marker of left ventricular systolic function, on the relationship between brachial-ankle pulse wave velocity (baPWV) and LVH. METHODS A total of 1146 patients were included in the study. The baPWV and bPEP/bET were measured using an ABI-form device. Patients were classified into four groups. Groups 1, 2, 3, and 4 were patients with bPEP/bET ≤ 0.38 and baPWV below the median, bPEP/bET > 0.38 but baPWV below the median, bPET/bET ≤ 0.38 but baPWV above the median, and bPET/bET > 0.38 and baPWV above the median, respectively. RESULTS Patients in groups 3 and 4 (high baPWV) and patients in group 2 (low baPWV but high bPEP/bET) were associated with increased left ventricular mass index (LVMI) and LVH (all P < 0.001). In a multivariate model, baPWV was significantly associated with LVMI (P = 0.007) and LVH (P = 0.025). Further adjustment for bPEP/bET made the association between baPWV and LVMI (P = 0.150) and LVH (P = 0.173) disappear. CONCLUSIONS The bPEP/bET has an important impact on the relationship between baPWV and LVH. Therefore, the value of bPEP/bET obtained from the same examination should be considered while interpreting the relationship between baPWV and LVH.

Brachial-Ankle Pulse Wave Velocity and Systolic Time Intervals in Risk Stratification for Progression of Renal Function Decline

BACKGROUND Cardiovascular dysfunction was associated with progression of renal function decline. This study was to assess whether combination of brachial-ankle pulse wave velocity (baPWV) and the ratio of brachial pre-ejection period (bPEP) to brachial ejection time (bET) was independently associated with progression of renal function decline. METHODS We included 363 patients and classified them into four groups according to median values of bPEP/bET and baPWV. Groups 1, 2, 3, and 4 were patients with bPEP/bET and baPWV below the median, bPEP/bET above but baPWV below the median, bPET/bET below but baPWV above the median, and bPET/bET and baPWV above the median, respectively. The decline in renal function was assessed by the estimated glomerular filtration rate (eGFR) slope and the renal end points were defined as commencement of dialysis or ≥25% decline in eGFR. The relative risk of renal end points was analyzed by Cox regression method. RESULTS The eGFR slope was significantly associated with baPWV, bPEP/bET, and patients in groups 2, 3, and 4 (vs. group 1) (P < 0.006). Multivariate forward Cox regression analysis showed that high baPWV, high bPEP/bET, and patients in groups 2, 3, and 4 (vs. group 1) (P ≤ 0.047) were independent predictors of renal end points. CONCLUSIONS Our results demonstrated higher baPWV and bPEP/bET were associated with faster renal function decline and adverse renal end points. Dividing patients into four groups using these two parameters might be useful in risk stratification for progression of renal function decline.

Anemia as an Independent Predictor of Adverse Cardiac Outcomes in Patients with Atrial Fibrillation.

Background: Anemia and echocardiographic systolic and diastolic parameters are useful predictors of cardiovascular outcomes in patients with atrial fibrillation (AF). However, no studies have evaluated the use of anemia for predicting cardiovascular outcome in AF patients when the important echocardiographic parameters are known. Therefore, this study was designed to evaluate whether low hemoglobin is a useful parameter for predicting poor cardiac outcome after adjustment for important echocardiographic parameters in AF patients. Methods: Index beat method was used to measure echocardiographic parameters in 166 patients with persistent AF. Cardiac events were defined as death and hospitalization for heart failure. The association of hemoglobin with adverse cardiac events was assessed by Cox proportional hazards model. Results: The 49 cardiac events identified in this population included 21 deaths and 28 hospitalizations for heart failure during an average follow-up of 20 months (25th-75th percentile: 14-32 months). Multivariable analysis showed that increased left ventricular mass index (LVMI) and decreased body mass index, estimated glomerular filtration rate, and hemoglobin (hazard ratio 0.827; P = 0.015) were independently associated with increased cardiac events. Additionally, tests of a Cox model that included important clinic variables, LVMI, left ventricular ejection fraction, and the ratio of transmitral E-wave velocity to early diastolic mitral annulus velocity showed that including hemoglobin significantly increased value in predicting adverse cardiac events (P = 0.010). Conclusions: Hemoglobin is a useful parameter for predicting adverse cardiac events, and including hemoglobin may improve the prognostic prediction of conventional clinical and echocardiographic parameters in patients with AF.

A comparison between brachial and echocardiographic systolic time intervals.

Systolic time interval (STI) is an established noninvasive technique for the assessment of cardiac function. Brachial STIs can be automatically determined by an ankle-brachial index (ABI)-form device. The aims of this study are to evaluate whether the STIs measured from ABI-form device can represent those measured from echocardiography and to compare the diagnostic values of brachial and echocardiographic STIs in the prediction of left ventricular ejection fraction (LVEF) <50%. A total of 849 patients were included in the study. Brachial pre-ejection period (bPEP) and brachial ejection time (bET) were measured using an ABI-form device and pre-ejection period (PEP) and ejection time (ET) were measured from echocardiography. Agreement was assessed by correlation coefficient and Bland-Altman plot. Brachial STIs had a significant correlation with echocardiographic STIs (r = 0.644, P<0.001 for bPEP and PEP; r  = 0.850, P<0.001 for bET and ET; r = 0.708, P<0.001 for bPEP/bET and PEP/ET). The disagreement between brachial and echocardiographic STIs (brachial STIs minus echocardiographic STIs) was 28.55 ms for bPEP and PEP, -4.15 ms for bET and ET and -0.11 for bPEP/bET and PEP/ET. The areas under the curve for bPEP/bET and PEP/ET in the prediction of LVEF <50% were 0.771 and 0.765, respectively. Brachial STIs were good alternatives to STIs obtained from echocardiography and also helpful in prediction of LVEF <50%. Brachial STIs automatically obtained from an ABI-form device may be helpful for evaluation of left ventricular systolic dysfunction.

Impact of a systolic parameter, defined as the ratio of right brachial pre-ejection period to ejection time, on the relationship between brachial-ankle pulse wave velocity and left ventricular diastolic function

Arterial stiffness is correlated with left ventricular (LV) diastolic function as well as susceptibility to LV systolic function. Therefore, if LV systolic function is not known, the relationship between arterial stiffness and LV diastolic function is difficult to determine. A total of 260 patients were included in the study. The brachial-ankle pulse wave velocity (baPWV) and the ratio of right brachial pre-ejection period to ejection time (rbPEP/rbET) were measured using an ABI-form device. Patients were classified into four groups. Groups 1, 2, 3 and 4 were patients with rbPEP/rbET and baPWV below the median, rbPEP/rbET above but baPWV below the median, rbPET/rbET below but baPWV above the median, and rbPET/rbET and baPWV above the median, respectively. The LV ejection fractions in groups 1 and 3 were higher than those in groups 2 and 4 (P<0.001 for all). Patients in group 1 had a lower left atrial volume index (LAVI) and higher early diastolic mitral annular velocity (Ea) than patients in the other groups (P≤0.002). Patients in group 2 had a LAVI and ratio of transmitral E wave velocity to Ea that were comparable to those in groups 3 and 4. In conclusion, rbPEP/rbET had an impact on the relationship between baPWV and LV diastolic function. In patients with high rbPEP/rbET but low baPWV, low baPWV may not indicate good LV diastolic function but implies that cardiac dysfunction may precede vascular dysfunction in such patients. When interpreting the relationship between baPWV and LV diastolic function, the rbPEP/rbET value obtained from the same examination should be considered.