Author + information
- Kenya Kusunose, MD, PhD,
- Hirotsugu Yamada, MD, PhD⁎ (, )
- Susumu Nishio, RMS,
- Rina Tamai, RMS,
- Toshiyuki Niki, MD,
- Koji Yamaguchi, MD, PhD,
- Yoshio Taketani, MD,
- Takashi Iwase, MD, PhD,
- Takeshi Soeki, MD, PhD,
- Tetsuzo Wakatsuki, MD, PhD and
- Masataka Sata, MD, PhD
- ↵⁎Department of Cardiovascular Medicine, Tokushima University Hospital, 2-50-1 Kuramoto, Tokushima, Japan
Recently, the time interval between the onset of early diastolic transmitral flow velocity (E) and mitral annular velocity (e′) (TE-e′) was proposed as a new index representing left ventricular (LV) relaxation. A problem with the measurement of TE-e′ was that E and e′ could not be measured in the same beat. However, a novel dual Doppler echocardiographic method has been introduced that allows the measurement of both E and e′ in the same beat (1), and E/e′ and TE-e′ can be instantly calculated. The aims of this study were to: 1) investigate the usefulness of single-beat TE-e′ compared with invasive hemodynamic measurements; and 2) determine the impact of pre-load alterations by leg-positive pressure (LPP) on the relationship between TE-e′ and increased LV filling pressure.
We designed a prospective study to assess 42 consecutive patients who underwent catheterization for diagnosis of stable angina pectoris. Twenty-one age- and sex-matched healthy volunteers served as the control group. Patients with atrial fibrillation, valve diseases, severe heart failure, LV systolic dysfunction (LV ejection fraction <40%), or a regional wall motion abnormality at the basal, lateral, or septal region were excluded.
A total of 63 pairs of echocardiographic examinations were performed at baseline and during LPP. We used an ultrasound machine EUB-7500 (Hitachi Medical Corporation, Kashiwa, Japan). A 5-F Millar transducer with single lumen was introduced into the LV. Tau and LV end-diastolic pressure (LVEDP) were determined from the LV pressure curve, and measurements were performed simultaneously with the echocardiographic measurements. We customized a commercially available leg massage machine (Dr. Medomer DM-5000EX, Medo Industries, Tokyo, Japan) because it could maintain the same pressure loading (90 mm Hg) for 5 min.
Values are expressed as mean ± SD. The diagnostic ability of echocardiographic parameters to discriminate elevated LVEDP (>16 mm Hg) was determined by analysis of receiver-operating characteristic (ROC) curves. Reproducibility was expressed as the intraclass correlation coefficients (ICC) in a group of 10 randomly selected subjects by 1 observer, and then repeated on 2 separate days by 2 investigators.
The clinical characteristics and the influence of LPP in both groups are shown inTable 1. A representative case is shown inFigure 1. There was a correlation between TE-e′ and LVEDP at baseline (r = 0.71, p < 0.001) and during LPP (r = 0.82, p < 0.001). There was also a relationship between the change in LVEDP in response to LPP and the change in TE-e′ (r = 0.50, p < 0.001). The TE-e′ (standardized beta = 0.73, p < 0.001 at baseline and standardized beta = 0.89, p < 0.001 during LPP) was an independent predictor of the LVEDP in multivariate regression analysis with adjustment for age and sex. A ROC curve (area under the curve [AUC] = 0.93) was used to select a TE-e′ cutoff of 38 ms (specificity: 91%; sensitivity: 85%) to predict elevated LVEDP (>16 mm Hg) during LPP. For differentiating elevated LVEDP during LPP, the AUC was significantly higher for the TE-e′ compared with E/e′ (AUC = 0.93 vs. AUC = 0.72, p = 0.004). The TE-e′ (standardized beta = 0.42, p = 0.011 at baseline and standardized beta = 0.71, p < 0.001 during LPP) were also independent predictors of tau in multivariate regression analysis with adjustment for age and sex. The ICC of intraobserver variability was 0.98 (p < 0.001), and interobserver variability was 0.95 (p < 0.001).
This study is the first to demonstrate that single-beat TE-e′ correlated with invasively measured LV diastolic pressure, and that the TE-e′ was a better predictor of LV filling pressure than E/e′. In addition, our study showed that TE-e′ is pre-load–dependent compared with other Doppler parameters of LV diastolic function. TE-e′ could be influenced by pre-load changes, especially with impaired LV relaxation.
We postulate that because the mitral E begins with the crossing of left atrial (LA) and LV pressures, an augmentation of LA pressure might shorten the time needed for LA and LV pressures to cross, and this would shorten the isovolumic relaxation time. The onset of e′ is influenced by LV active relaxation and the cardiac restoring forces in end diastole. As LV relaxation is delayed and early diastolic suction is reduced, the onset of e′ is delayed and follows the onset of the E wave. In addition, an augmentation in pre-load might prolong the duration of systole and delay the onset of e′. For these reasons, TE-e′ was prolonged by a pre-load increase. The main limitation of this study was the small number of patients with elevated LVEDP at baseline (8 of 42).
Elevation of LVEDP prolongs TE-e′, and this may be due to enhanced early diastolic mismatch between mitral inflow and annular motion. TE-e′ is a sensitive noninvasive index for the estimation of LVEDP, and dual Doppler echocardiography is a practical method for the accurate measurement of this index in a single beat.
- American College of Cardiology Foundation