Aristomenis Manouras

Visually estimated ejection fraction by two dimensional and triplane echocardiography is closely correlated with quantitative ejection fraction by real-time three dimensional echocardiography.

BackgroundVisual assessment of left ventricular ejection fraction (LVEF) is often used in clinical routine despite general recommendations to use quantitative biplane Simpsons (BPS) measurements. Even thou quantitative methods are well validated and from many reasons preferable, the feasibility of visual assessment (eyeballing) is superior. There is to date only sparse data comparing visual EF assessment in comparison to quantitative methods available. The aim of this study was to compare visual EF assessment by two-dimensional echocardiography (2DE) and triplane echocardiography (TPE) using quantitative real-time three-dimensional echocardiography (RT3DE) as the reference method.MethodsThirty patients were enrolled in the study. Eyeballing EF was assessed using apical 4-and 2 chamber views and TP mode by two experienced readers blinded to all clinical data. The measurements were compared to quantitative RT3DE.ResultsThere were an excellent correlation between eyeballing EF by 2D and TP vs 3DE (r = 0.91 and 0.95 respectively) without any significant bias (-0.5 ± 3.7% and -0.2 ± 2.9% respectively). Intraobserver variability was 3.8% for eyeballing 2DE, 3.2% for eyeballing TP and 2.3% for quantitative 3D-EF. Interobserver variability was 7.5% for eyeballing 2D and 8.4% for eyeballing TP.ConclusionVisual estimation of LVEF both using 2D and TP by an experienced reader correlates well with quantitative EF determined by RT3DE. There is an apparent trend towards a smaller variability using TP in comparison to 2D, this was however not statistically significant.

Direct Measurement of Left Ventricular Outflow Tract Area Using Three‐Dimensional Echocardiography in Biplane Mode Improves Accuracy of Stroke Volume Assessment

Aims: The aim of the study was to investigate whether left ventricular stroke volume (LVSV) assessment using direct measurement of left ventricular outflow tract area (LVOTA) is superior to conventional methods for SV calculation. Methods and results: Thirty patients were included in the study (39 ± 12 years). LVSV was assessed by multiplying LVOT velocity time integral (VTI) by LVOTA provided by direct planimetrical measurements from real time three‐dimensional echocardiography (RT3DE) in biplane mode (SV2). These measurements were compared to conventional methods using either the LVOT diameter for LVOTA multiplied with VTI (SV1) or biplane Simpson (SV3). Direct SV measurements by RT3DE were used as gold standard (SVref). There was an excellent correlation and agreement between SV determined by SV2 and 3DE (r = 0.98, mean difference 0.5 ± 3.3 mL). However, the concordance of the traditional methods (SV1 and SV3) with 3DE was weaker (r = 0.38, mean difference −2.0 ± 17.6 mL, r = 0.84, mean difference −7.6 ± 8.7 mL, respectively). Furthermore, cardiac output (CO) measurements performed by the different modalities were not concordant with wide limits of agreement, except by SV2 the mean difference of CO by SV1 was −0.12 ± 1.05 L/min, 0.03 ± 0.20 L/min by SV2, and −0.45 ± 0.52 L/min by SV3. Conclusions: SV and CO calculations using direct measurement of LVOT area is a feasible, accurate and reproducible method and correlates extremely well with 3DE volume measurements. SV and CO calculation by LVOTA is therefore an appealing method for LVSV assessment in clinical routine. (Echocardiography 2010;27:1078‐1085)

Three-dimensional echocardiography using single-heartbeat modality decreases variability in measuring left ventricular volumes and function in comparison to four-beat technique in atrial fibrillation

BackgroundThree dimensional echocardiography (3DE) approaches the accuracy of cardiac magnetic resonance in measuring left ventricular (LV) volumes and ejection fraction (EF). The multibeat modality in comparison to single-beat (SB) requires breath-hold technique and regular heart rhythm which could limit the use of this technique in patients with atrial fibrillation (AF) due to stitching artifact. The study aimed to investigate whether SB full volume 3DE acquisition reduces inter- and intraobserver variability in assessment of LV volumes and EF in comparison to four-beat (4B) ECG-gated full volume 3DE recording in patients with AF.MethodsA total of 78 patients were included in this study. Fifty-five with sinus rhythm (group A) and 23 having AF (group B). 4B and SB 3DE was performed in all patients. LV volumes and EF was determined by these two modalities and inter- and intraobserver variability was analyzed.ResultsSB modality showed significantly lower inter- and intraobserver variability in group B in comparison to 4B when measuring LV volumes and EF, except for end-systolic volume (ESV) in intraobserver analysis. There were significant differences when calculating the LV volumes (p < 0.001) and EF (p < 0.05) with SB in comparison to 4B in group B.ConclusionSingle-beat three-dimensional full volume acquisition seems to be superior to four-beat ECG-gated acquisition in measuring left ventricular volumes and ejection fraction in patients having atrial fibrillation. The variability is significantly lower both for ejection fraction and left ventricular volumes.

Transesophageal echocardiography measurements of aortic annulus diameter using biplane mode in patients undergoing transcatheter aortic valve implantation

BackgroundAortic stenosis (AS) is a relevant common valve disorder. Severe AS and symptoms and/or left ventricular dysfunction (EF <50%) have the indication for aortic valve replacement (AVR). Majority of the patients with AS are elderly often with co-morbidities and generally have high preoperative risk. Transcatheter aortic valve implantation (TAVI) is offered in this group. Four different sizes of Corevalve prosthesis are available. Correct measurement of aortic size prior to TAVI is of great important to choose the right prosthesis size to avoid among others paravalvular leak or prosthesis patient mismatch.Aim of the study is to assess the aortic annulus diameter in patients undergoing TAVI by biplane (BP) mode using transesophageal echocardiography (TEE) and compare it to two-dimensional (2D) transthoracic echocardiography (TTE) and 2DTEE using three-dimensional (3D) TEE as reference method.MethodsThe study population consisted of 50 patients retrospectively (24 men and 26 women, mean age 85±8 years of age) who all had undergone echocardiography examination prior to TAVI.ResultsThe mean aortic annulus diameter was 20.4±2.2 mm with TTE, 22.3±2.5 mm with 2DTEE, 22.9±1.9 mm with BP-mode and 23.1±1.9 mm with 3DTEE. TTE underestimated the mean aortic annulus diameter in comparison to transesophageal imaging modalities (p<0.001). Using 3DTEE, 2% of patients were unsuitable for TAVI due to a too-small AoA (n=1). This figure was similar with BP (4%, n=2; p=1.00) but considerably larger with 2DTTE (36%, n=18; p < 0.001) and 2DTEE (12%, n=6; p=0.06). There was a strong correlation between BP-mode and 3DTEE for assessment of aortic annulus diameter (r-value 0.88) with small mean difference (−0.2±0.9 mm) whereas the other modalities showed larger 95% confidence interval and modest correlation (2DTTE vs. 3DTEE, –6.3 to 0.9 mm, r=0.64 and 2DTEE vs. 3DTEE, –4.8 to 3.2 mm, r=0.61).ConclusionA multi-dimensional method is preferred to assess aortic annulus diameter in TAVI patients since there is risk of underestimation using single plane. Biplane mode is the method of choice in view of speedy post-processing with no need for expensive dedicated software. Lastly, single plane methods lead to misclassification of patients as unsuitable for TAVI. This may be of major clinical importance.

Arterial vasodilatory and ventricular diastolic reserves determine the stroke volume response to exercise in elderly female hypertensive patients

Elderly female hypertensives with arterial stiffening constitute a majority of patients with heart failure with preserved ejection fraction (HFpEF), a condition characterized by inability to increase cardiac stroke volume (SV) with physical exercise. As SV is determined by the interaction between the left ventricle (LV) and its load, we wished to study the role of arterial hemodynamics for exertional SV reserve in patients at high risk of HFpEF. Twenty-one elderly (67 ± 9 yr) female hypertensive patients were studied at rest and during supine bicycle stress using echocardiography including pulsed-wave Doppler to record flow in the LV outflow tract and arterial tonometry for central arterial pressure waveforms. Arterial compliance was estimated based on an exponential relationship between pressure and volume. The ratio of aortic pressure-to-flow in early systole was used to derive characteristic impedance, which was subsequently subtracted from total resistance (mean arterial pressure/cardiac output) to yield systemic vascular resistance (SVR). It was found that patients with depressed SV reserve (NoRes; reserve <15%; n = 10) showed decreased arterial compliance during exercise, while patients with SV reserve ≥15% (Res; n = 11) showed increased compliance. Exercise produced parallel increases in LV end-diastolic volume and arterial volume in Res patients while NoRes patients exhibited a lesser decrease in SVR and a drop in effective arterial volume. Poor SV reserve in elderly female hypertensives is due to simultaneous failure of LV preload and arterial vasodilatory reserves. Abnormal arterial function contributes to a high risk of HFpEF in these patients.

The pulmonary capillary wedge pressure accurately reflects both normal and elevated left atrial pressure.

BACKGROUND Pulmonary capillary wedge pressure (PCWP) is routinely used as an indirect measure of the left atrial pressure (LAP), although the accuracy of this estimate, especially under pathological hemodynamic conditions, remains controversial. OBJECTIVES The aim of this prospective study was to investigate the reliability of PCWP for the evaluation of LAP under different hemodynamic conditions. METHODS Simultaneous left and right heart catheterization data of 117 patients with pure mitral stenosis, obtained before and immediately after percutaneous mitral comissurotomy, were analyzed. RESULTS A strong correlation and agreement between PCWP and LAP measurements was demonstrated (correlation coefficient = 0.97, mean bias ± CI, 0.3 ± -3.7 to 4.2 mm Hg). Comparison of measurements performed within a 5-minute interval and those performed simultaneously revealed that simultaneous pressure acquisition yielded better agreement between the 2 methods (bias ± CI, 1.82 ± 1.98 mm Hg). In contrast to previous observations, the discrepancy between the 2 measures did not increase with elevated PCWP. Multiple regression analysis failed to identify hemodynamic confounders of the discrepancy between the 2 pressures. The ability of PCWP to distinguish between normal and elevated LAP (cutoff set at 12 and 15 mm Hg, respectively), as tested by receiver operating characteristics analysis, demonstrated a remarkably high diagnostic accuracy (area under the curve: 0.989 and 0.996, respectively). CONCLUSIONS Although the described limits of agreement may not allow the interchangeability of PCWP and LAP, especially at lower pressure ranges, our data support the clinical use of PCWP as a robust and accurate estimate of LAP.

Two-Dimensional Color Doppler Echocardiography for Left Ventricular Stroke Volume Assessment: A Comparison Study with Three-Dimensional Echocardiography

Aim: Whether measurement of left ventricular outflow tract diameter (LVOTd) using color Doppler (CD) in order to more accurately define LVOTd is more accurate for determination of stroke volume (SV) than gray scale and compare it with direct measurement of LVOT area (a) using three‐dimensional echocardiography (3DE) for SV determination. Methods and Results: Twenty‐one volunteers were examined. LVOTa was calculated by two‐dimensional echocardiography (2DE) using the following formula: π× (d/2)2, d = LVOT diameter by gray scale and CD, respectively. Planimetry of LVOTa was performed in parasternal long axis using 3DE. Eccentricity Index was calculated using the lateral and anterior‐posterior LVOTd. SV was obtained by four different methods: (1) 2D gray scale, (2) 2D color, (3) LVOTa × LVOT velocity time integral, and (4) SV by Simpsons biplane method. Gray scale LVOTd was significantly smaller compared to LVOTd obtained with CD (P < 0.05). Significant differences occurred between LVOTa gray scale and CD (3.29 ± 0.74 cm2 vs 3.67 ± 0.70 cm2, P < 0.05) and between LVOTa calculated by gray scale in comparison to 3DE planimetry; (3.29 ± 0.74 cm2 vs 3.61 ± 0.89 cm2, P = 0.011). Half of the subjects had at least 17% difference between the lateral and anterior‐posterior LVOTd. There were significant differences between SV by 2D gray scale and 2D CD (82.8 ± 17.1 mL vs 92.4 ± 16.8 mL, P < 0.05) and between 2D gray scale and 3DE planimetry (82.8 ± 17.1 mL vs 90.7 ± 19.8 mL, P = 0.025). Conclusion: Our study demonstrates LVOT being frequently elliptical. SV and LVOTa were found to be similar when comparing 2DE CD and 3DE planimetry and showed higher values in comparison to 2DE gray scale, which suggests 2DE CD to be an alternative approach for SV assessment.

Measurements of left ventricular myocardial longitudinal systolic displacement using spectral and colour tissue Doppler: time for a reassessment?

BackgroundEchocardiographic measurements of left ventricular (LV) myocardial displacement may produce different results depending on the choice of employed modality and subjective adjustments during data acquisition and analysis.MethodsIn this study, left ventricular longitudinal systolic displacement was quantified in 57 patients (31 women and 26 men, 50 ± 16 years) using colour (colour TD) and spectral tissue Doppler (spectral TD) before and after temporal filtering (30 to 70 milliseconds in 20-millisecond steps) and changed offline gain saturation (0%, 50% and 100%), respectively. The results were compared with those obtained with anatomic M-mode.ResultsWhereas only minor differences occurred between the results of colour TD and anatomic M-mode measurements, spectral TD significantly overestimated the results obtained with both these methods. However, the limits of agreement between the results produced by all three studied methods were not clinically acceptable in any of the cases. The spectral TD displacement values increased along with increasing offline gain saturation whereas the effect of temporal filtering on colour Doppler measurements was insignificant.ConclusionMeasurements of LV myocardial longitudinal displacement employing spectral TD, colour TD or anatomic M-mode produce different results, thus discouraging interchangeable use of these modalities. Whereas the results of spectral TD measurements can be significantly altered by changing offline gain setting, the effect of temporal filtering on colour TD measurements is insignificant, a fact that increases clinical practicality of the latter method.

The value of E/Em ratio in the estimation of left ventricular filling pressures: impact of acute load reduction: a comparative simultaneous echocardiographic and catheterization study.

BACKGROUND The ratio of the early transmitral flow velocity to the early diastolic tissue velocity (E/Em) has been suggested as a reliable estimate of left ventricular diastolic pressures (LVDP). However, the evidence regarding the ability of E/Em to detect LVDP changes is relatively equivocal. Our aim was to evaluate the validity of the ratio following acute load reduction. METHODS AND RESULTS 68 consecutive patients referred for coronary angiography underwent LV catheterization and echocardiography simultaneously. Doppler signals of transmitral flow and spectral TD signals at the level of the mitral annulus were obtained before and directly after intravenous administration of nitroglycerin (NTG). The predictive ability of E/Em to identify elevated LVDP was modest (area under curve=0.71 ± 0.08, p<0.01). The index was more strongly associated with LVDP in patients with reduced ejection fraction (EF)<55% (r=0.68; p<0.01) than in patients with normal EF. Following NTG, E/Em lacked any predictive potential for elevated LVDP whereas changes LVDP could not be reliably tracked using E/Em. CONCLUSION The predictive capacity of E/Em for elevated LVDP was weak and declined significantly following acute reduction in LV load. Changes in LVDP were not reliably predicted by E/Em. The current findings derived from a real-world patient population with relatively high filling pressures indicate that E/Em may not be sufficiently robust to be employed as a single non-invasive estimate of LVDP nor for monitoring load reducing medical therapy.

Effects of Prolonged Exercise on Left Ventricular Mechanical Synchrony in Long-Distance Runners: Importance of Previous Exposure to Endurance Races

BACKGROUND Prolonged exercise has been shown to lead to elevated levels of cardiac troponin and altered cardiac function on echocardiography. It is not known if cardiac synchrony is altered by prolonged exercise. The aims of this study were to assess changes in intra-left ventricular mechanical synchrony and circulating levels of cardiac troponin following prolonged exercise and to evaluate the importance of prior exposure to endurance racing. METHODS Forty-three male participants in a 30-km cross-country race (20 new participants at this event [median, 3 previous endurance races] age matched against 23 repeat participants [median, 31 previous endurance events]) were assessed prospectively 1 to 2 days before and 24 hours after the race using troponin T and Doppler tissue imaging analyzing the standard deviation of time to peak myocardial systolic velocity (T(s)-SD) in a six-basal, six-midventricular segment model measuring myocardial synchrony. The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene was also analyzed, as I allele carriers reportedly have superior endurance performance, while the D allele predisposes to renin-angiotensin system-induced cardiac remodeling. RESULTS Prerace troponin T was undetectable in all runners, and postrace levels were higher in new runners (median, 0.03 microg/L; interquartile range [IQR], 0.01-0.04 microg/L) than in repeat runners (median, 0.01 microg/L; IQR, 0.01-0.02 microg/L) (P = .03). Although new and repeat runners had similar T(s)-SD at baseline (32 msec [IQR, 22-43 msec] vs 34 msec [IQR, 29-45 msec], P = .13), dyssynchrony increased only in new runners (40 msec [IQR, 31-47 msec], P < .001; in repeat runners, median, 38 msec [IQR, 29-43 msec], P = .30; median relative difference, +13% vs +5%, P = .02). ACE genotype distribution was similar in both groups. Multivariate analysis showed that (1) a lack of prior endurance exposure; (2) more copies of the ACE D allele; and (3) lower peak systolic velocity were independent predictors of postrace dyssynchrony (P < .05 for all). CONCLUSION Prolonged exertion increased ventricular mechanical dyssynchrony in new endurance participants and in ACE D allele carriers. The long-term impact of such changes warrants future study.