Biomedical subjects

Erwan Donal

Publications and source records attributed to Erwan Donal.

18 recordsLinked to original sources

PubMed2008

Contrast-enhanced tissue Doppler imaging of the left atrial appendage is a new quantitative measure of spontaneous echocardiographic contrast in atrial fibrillation.

AIMS: Although left atrial appendage spontaneous echo contrast (LAASEC) is a marker of increased thromboembolic risk in atrial fibrillation, it has previously only been evaluated qualitatively. We sought to determine if an intravenous contrast echocardiographic agent combined with tissue Doppler imaging (TDI) of the LAA could accurately quantify LAA-SEC in patients with atrial fibrillation. METHODS AND RESULTS: We prospectively identified 55 patients with persistent atrial arrhythmias (mean age 63+/-13 years) undergoing a transesophageal echocardiography (TEE), with LAA-SEC prior to direct current cardioversion. In addition to off-line calculation of backscatter index and shear rate, quantification of the velocity in a color TDI region of interest was performed in the LAA cavity following a 0.5-mL intravenous bolus of Optison. LAA-SEC was qualitatively graded by a blindedreader as mild (n = 29) or severe (n = 26), and was compared off-line to TEE-derived quantitative variables. Compared to patients with mild LAA-SEC, those with severe LAA-SEC had significantly decreased LAA emptying velocity, LAA TDI mean velocities and shear rate. Over the whole group, the mean maximal velocity of the LAA using TDI correlated with LAA emptying velocity (r = 0.59; P < 0.0001), shear rate (r = 0.55; P < 0.0001) and LAA area (r = 0.34; P = 0.014). Severe LAA-SEC was found with 72% sensitivity and 82% specificity if TDI mean velocity was <6.13 cm/s. On logistic regression analysis, LAA-TDI was the only predictor of qualitative LAA-SEC grade. CONCLUSION: Contrast-enhanced TDI is an original new tool that provides a quantification of the mean velocity of LAA-SEC that might improve our decision making in patients with atrial fibrillation.

Albumins↗

PubMed2006

Echocardiographic right ventricular strain analysis in chronic heart failure.

OBJECTIVE: We sought to compare the additive value of right ventricular (RV) function assessed by longitudinal systolic strain (epsilon% - ROI: 9.2 at 10.8 mm) with cardiopulmonary exercise testing (CPET) or brain natriuretic peptide (BNP) in patients with heart failure (HF). METHOD: We studied 19-patients (age = 56 +/- 8 years) in New York Heart Association HF class III-IV, who underwent standard and tissue Doppler echocardiography, CPET and BNP measurements on the same day. RV function was assessed by systolic strain (epsilon, %, ROI: 9.2-10.8 mm) in the mid-segment. Clinical outcomes were examined at 6 months. RESULTS: epsilon (-19.9+/-6.8%) was correlated with BNP (R = 0.52, P = 0.02), slope VE/VCO(2) (R = -0.65, P = 0.003), peak VO(2) (R = 0.46, P = 0.04) and the maximal workload (Watts) developed during CPET (R = 0.54, P=0.02). During follow-up, 1-patient died, 1-underwent heart transplantation, and 4 were re-hospitalized for worsening HF. Patients with major adverse cardiac events (MACE) had a significantly higher mean BNP concentration (852.8 ng/mL +/- 1114.3 vs. 201.4+ /- 293.8, P = 0.03), higher VE/VCO(2) (41.3 +/- 3.6 vs. 35.0 +/- 4.8 P < 0.001) and lower epsilon (-13.9 +/- 4.9 vs. -22.2+ /- 5.8, P < 0.001) than patients who remained MACE-free. By multivariate analysis, ST was the only predictor of MACE. CONCLUSION: In HF-patients presenting, RV-function assessed by systolic epsilon was reliable, easily measurable and a stronger prognosticator than CPET or BNP.

Chronic Disease↗

PubMed2006

Effects of cardiac resynchronization therapy on disease progression in chronic heart failure.

Despite the alleviation of symptoms and longer survival conferred by pharmacological management of chronic congestive heart failure (CHF), this progressive syndrome remains associated with high morbidity and premature death. A new treatment of CHF should ideally alleviate symptoms, improve functional capacity, decrease mortality, and slow or reverse its progression without adding risks for the patient that outweighs the benefits. Growing evidence indicates that devices implanted to resynchronize ventricular contraction are a beneficial adjunct in the treatment of CHF. This review discusses the remodelling process, and its clinical and prognostic significance. We also discuss the impact of CRT, on remodelling and disease progression with a particular focus on patients with asymptomatic or mild heart failure (NYHA Class I-II).

Cardiac Pacing, Artificial↗

PubMed2006

Cardiac resynchronisation therapy in heart failure: current status.

Cardiac resynchronization in heart failure already has a history of 12 years. However, the major advances have been the result of large multi center trials dating from 2001. In all these trials patients with a LVEF < or = 35% were included, and a QRS above 120 msec. Follow up was from 3-36 months. The majority of these trials showed a positive effect in reduction of composite and points of death or hospitalization for major cardiovascular events. Many of these trials also showed a diminution of left ventricular and systolic diameter or volume. Even in NYHA class II patients an improvement was seen. Some unanswered questions still remain as regards the agreement on electrical or electromechanical dyssynchrony criteria. There is a number of patients with "wide" QRS who do not improve and conversely a number of patients with a narrow QRS who witness improvement. The benefit in patients with atrial fibrillation also remains unanswered. Finally the value of this modality in patients with mild heart failure or asymptomatic left ventricular systolic dysfunction, NYHA class I-II remains to be determined in large on going trials. Another question is whether biventricular or left ventricular patient is preferable. Finally whether biventricular patient should be complemented by a defibrillator insertion is being currently studied. Cardiac resynchronization therapy along or in combination with an ICD improves symptoms, reduces major morbidity and mortality in patients with a left ventricular EF<35%, ventricular dilatation and a QRS > or = 120 msec in NYHA class III-IV. Further indications are currently being examined.

Cardiac Pacing, Artificial↗

PubMed2006

Chronic ischemic mitral regurgitation.

Ischemia-induced mitral insufficiency (IMI) can occur when a papillary muscle ruptures in the acute phase of myocardial infarction (MI) or, more commonly, when ischemic heart disease reaches the chronic stage, with or without infarction. In the latter case it can be distinguished from organic mitral regurgitation because the structure of the valve and the subvalvular apparatus are not affected. Many factors contribute to the complex mechanism of IMI: incomplete closure of the valve is mainly a result of changes in the geometry of the left ventricle, the mitral annulus, papillary muscles and to hemodynamic conditions rather than to muscular dysfunction of the papillary muscles. IMI is assessed mainly by Doppler echocardiography. The adverse prognostic value of chronic IMI following an infarction has recently been described. Regurgitant orifice area (ROA) > 20 mm2 and a resting regurgitated volume > 30 ml or an increase in ROA > 13 mm2 on the treadmill-exercise echocardiogram were identified as relevant predictors of death. The therapeutic implications, both surgical and interventional, are currently under development using annuloplasty coupled, perhaps, to new strategies.

Chronic Disease↗

PubMed2005

Usefulness of Doppler assessment of pulmonary vein and left atrial appendage flow following pulmonary vein isolation of chronic atrial fibrillation in predicting recovery of left atrial function.

Atrial fibrillation (AF) is a widespread condition that causes significant morbidity and mortality. Recently, pulmonary venous (PV) isolation using radiofrequency ablation has been used successfully to exclude the pulmonary venous ostia, resulting in correction of AF. Further, miniaturized high-frequency ultrasound phased-array transducers currently provide Doppler and 2-dimensional imaging during the ablation procedure. We examined atrial function and its determinants using intracardiac echocardiography before and after PV isolation in 45 patients who had chronic AF (56 +/- 11 years old). PV, left atrial (LA) appendage, and mitral and tricuspid flows were recorded. Recovery of booster pump function (defined by the presence of mitral inflow A wave, LA appendage a-wave, and PV A-reversal wave velocities >10 cm/s) was observed in 39 of 45 patients (86.6%). PV flow systolic wave before and after ablation correlated with the degree of LA booster pump function after PV isolation. An early systolic PV flow peak velocity >57.47 cm/s predicted "good" LA booster pump function recovery with 96% specificity. Diastolic LA appendage emptying in AF correlated (p <0.001) and predicted good LA booster pump function with 92% specificity for velocities >46.4 cm/s. Thus, monitoring LA function during PV isolation for chronic AF is feasible. Most patients recovered LA booster pump function immediately after PV isolation, and the degree of recovery correlated with LA reservoir function. Preserved reservoir function during AF is predictive of satisfactory recovery of booster pump function after PV isolation.

Aged↗

PubMed2005

Tissue Doppler echocardiographic quantification. Comparison to coronary angiography results in Acute Coronary Syndrome patients.

BACKGROUND: Multiples indices have been described using tissue Doppler imaging (DTI) capabilities. The aim of this study was to assess the capability of one or several regional DTI parameters in separating control from ischemic myocardium. METHODS: Twenty-eight patients with acute myocardial infarction were imaged within 24-hour following an emergent coronary angioplasty. Seventeen controls without any coronary artery or myocardial disease were also explored. Global and regional left ventricular functions were assessed. High frame rate color DTI cineloop recordings were made in apical 4 and 2-chamber for subsequent analysis. Peak velocity during isovolumic contraction time (IVC), ejection time, isovolumic relaxation (IVR) and filling time were measured at the mitral annulus and the basal, mid and apical segments of each of the walls studied as well as peak systolic displacement and peak of strain. RESULTS: DTI-analysis enabled us to discriminate between the 3 populations (controls, inferior and anterior AMI). Even in non-ischemic segments, velocities and displacements were reduced in the 2 AMI populations. Peak systolic displacement was the best parameter to discriminate controls from AMI groups (wall by wall, p was systematically < 0.01). The combination IVC + and IVR< 1 discriminated ischemic from non-ischemic segments with 82% sensitivity and 85% specificity. CONCLUSION: DTI-analysis appears to be valuable in ischemic heart disease assessment. Its clinical impact remains to be established. However this simple index might really help in intensive care unit routine practice.

Acute Disease↗

PubMed2005

Quantitative regional analysis of left atrial function by Doppler tissue imaging-derived parameters discriminates patients with posterior and anterior myocardial infarction.

BACKGROUND: Doppler tissue imaging can now be used for the assessment of left atrial (LA) function. LA function was evaluated by this technique in a group of patients hospitalized for acute myocardial infarction and in a control population. METHODS: Patients were all prospectively imaged with a scanner. To study the LA, a region of interest was located in the proximal part of the lateral and septal LA walls. Doppler tissue imaging, tissue tracking, strain, and delays were recorded. RESULTS: In all, 12 patients with posterior (age 54 +/- 9 years) and 13 with anterior (age 64 +/- 16 years) acute myocardial infarction, along with 16 control patients (age 54 +/- 9 years), were analyzed. Early diastolic septal velocity was found to be the best parameter for discriminating among the 3 groups. Peak strain was also relevant and did not correlate with left ventricular function. CONCLUSIONS: LA is accessible to Doppler tissue imaging analysis. Strain can quantify LA function relatively independently of left ventricular function, and may provide new insights on LA function.

Aged↗

PubMed2005

Planimetric assessment of anatomic valve area overestimates effective orifice area in bicuspid aortic stenosis.

BACKGROUND: Although the continuity equation remains the noninvasive standard, planimetry using transesophageal echocardiography is often used to assess valve area for patients with aortic stenosis (AS). Not uncommonly, however, anatomic valve area (AVAA) obtained by planimetry overestimates continuity-derived effective valve area (AVAE) in bicuspid AS. METHODS: Transthoracic Doppler and transesophageal echocardiography were performed to obtain AVAE and AVAA in 31 patients with bicuspid AS (age 61 +/- 11 years) and 22 patients with degenerative tricuspid AS (age 71 +/- 13 years). Aortic root and left ventricular outflow tract dimensions and the directional angle of the stenotic jet were assessed in all patients. Using these data, a computational fluid dynamics model was constructed to test the effect of these variables in determining the relationship between AVAE and AVAA. RESULTS: For patients with tricuspid AS, the correlation between AVAA (1.15 +/- 0.36 cm2) and AVAE (1.13 +/- 0.46 cm2) was excellent (r = 0.91, P < .001, Delta = 0.02 +/- 0.21 cm2). However, AVAA was significantly larger (1.19 +/- 0.35 cm2) than AVAE (0.89 +/- 0.29 cm2) in the bicuspid AS group (r = 0.71, P < .001, Delta = 0.29 +/- 0.25 cm2). Computer simulation demonstrated that the observed discrepancy related to jet eccentricity. CONCLUSION: For a given anatomic orifice, functional severity tends to be greater in bicuspid AS than in tricuspid AS. This appears to be primarily related to greater jet eccentricity and less pressure recovery.

Anatomy, Cross-Sectional↗

PubMed2005

The left atrial appendage, a small, blind-ended structure: a review of its echocardiographic evaluation and its clinical role.

The increasing prevalence of stroke and atrial fibrillation is a stimulus for new therapeutic strategies and also warrants a review of imaging modalities of the most important source of cardiac systemic embolic events: the left atrial appendage (LAA). This blind-ended, complex structure is embryologically distinct from the body of the left atrium and is sometimes regarded as just a minor extension of the atrium. However, it should routinely be analyzed as part of a transesophageal echocardiographic (TEE) examination. A pulsed Doppler TEE analysis of LAA emptying flow should supplement a two-dimensional (2-D) analysis; these examinations have proven to be highly reproducible and to help assess thromboembolic risk. In 2-D imaging, potential thrombus and spontaneous echo contrast should be sought. In addition, LAA plays a hemodynamic role that participates in atrial function and is influenced by various hemodynamic conditions. In view of the embolic risks from a dysfunctional appendage, the LAA is often ligated during cardiac valve surgery. New devices are under evaluation for percutaneous closure of the LAA, and further studies should improve the definition, understanding, and treatment of LAA dysfunction.

Age Factors↗

PubMed2004

Influence of structural geometry on the severity of bicuspid aortic stenosis.

Doppler-derived gradients may overestimate total pressure loss in degenerative and prosthetic aortic valve stenosis (AS) due to unaccounted pressure recovery distal to the orifice. However, in congenitally bicuspid valves, jet eccentricity may result in a higher anatomic-to-effective orifice contraction ratio, resulting in an increased pressure loss at the valve and a reduced pressure recovery distal to the orifice leading to greater functional severity. The objective of our study was to determine the impact of local geometry on the total versus Doppler-derived pressure loss and therefore the assessed severity of the stenosis in bicuspid valves. On the basis of clinically obtained measurements, two- and three-dimensional computer simulations were created with various local geometries by altering the diameters of the left ventricular outflow tract (LVOT; 1.8-3.0 cm), orifice diameter (OD; 0.8-1.6 cm), and aortic root diameter (AR; 3.0-5.4 cm). Jet eccentricity was altered in the models from 0 to 25 degrees. Simulations were performed under steady-flow conditions. Axisymmetric simulations indicate that the overall differences in pressure recovery were minor for variations in LVOT diameter (<3%). However, both OD and AR had a significant impact on pressure recovery (6-20%), with greatest recovery being the larger OD and the smaller recovery being the AR. In addition, three-dimensional data illustrate a greater pressure loss for eccentric jets with the same orifice area, thus increasing functional severity. In conclusion, jet eccentricity results in greater pressure loss in bicuspid valve AS due to reduced effective orifice area. Functional severity may also be enhanced by larger aortic roots, commonly occurring in these patients, leading to reduced pressure recovery. Thus, for the same anatomic orifice area, functional severity is greater in bicuspid than in degenerative tricuspid AS.

Adult↗

PubMed2004

Evaluation of ventricular synchrony using novel Doppler echocardiographic indices in patients with heart failure receiving cardiac resynchronization therapy.

Cardiac resynchronization therapy improves hemodynamics in selected patients with heart failure. Mechanic asynchrony parameters that may guide patient selection or therapy optimization are still being investigated. A biventricular (BiV) pacemaker was implanted in 34 patients with dilated ischemic, idiopathic, or valvular cardiomyopathy, and a QRS duration of > or =130 milliseconds. Two-dimensional standard and Doppler tissue echocardiography was performed during right ventricular (RV), left ventricular (LV), BiV, and no pacing in a random and blinded manner. LV and BiV pacing increased stroke volume (P <.02 for both) and ejection fraction (P <.001 for both). Regional contractility assessed by displacement, strain rate, and peak systolic strain was improved in some segments (P <.05) during LV and BiV pacing. A homogenization of segmental contractions was observed during LV and BiV pacing as evaluated by net systolic displacement and segmental myocardial performance index. LV and BiV pacing provides benefits that can be quantified by echocardiography.

Analysis of Variance↗

PubMed2004

The pseudorestrictive pattern of transmitral Doppler flow pattern after conversion of atrial fibrillation to sinus rhythm: is atrial or ventricular dysfunction to blame?

Patients with paroxysmal atrial fibrillation (AF) who have recently converted from AF to sinus rhythm often exhibit a restrictive Doppler pattern in the transmitral flow (TMF) velocity. However, the mechanism of this phenomenon has not been well defined. We evaluated the temporal change of TMF pattern and hemodynamics after conversion of AF to in sinus rhythm in an animal model. Eight open-chest dogs underwent 3 hours of pacing-induced AF. TMF velocities and pressure data were acquired at baseline (sinus rhythm), immediately after conversion of AF, and every 10 minutes thereafter. Early diastolic TMF velocity was increased immediately after conversion and recovered to the baseline value in 20 minutes. Atrial systolic TMF velocity was reduced after AF and recovered to baseline value in 20 to 30 minutes. Early diastolic/atrial systolic TMF velocity was increased after conversion, and recovered to baseline value in 20 to 30 minutes. The mean left atrial (LA) pressure increased immediately, 10 and 20 minutes after the conversion of AF to sinus rhythm. The left ventricular end-diastolic pressure was increased and positive left ventricular dP/dt and tau were decreased immediately after AF, whereas they recovered within 10 minutes. In conclusion, a pseudorestrictive pattern of TMF after AF occurred as a result of transient LA mechanical functional impairment and increased LA pressure caused by LA stunning. Transient left ventricular diastolic dysfunction also effected the TMF velocity immediately after the conversion from AF to sinus rhythm, although it recovered faster than LA mechanical dysfunction.

Animals↗

PubMed2004

Anatomic M-mode, a pertinent tool for the daily practice of transthoracic echocardiography.

OBJECTIVES: We sought to compare anatomic M-mode (AMM), a new echocardiographic postprocessing option, and conventional M-mode (CMM) using fundamental imaging and tissue harmonic imaging. METHODS: Transthoracic echocardiography was performed in 15 selected patients to analyze the reproducibility of AMM and in 47 patients to assess its clinical value versus CMM. Acquisitions were performed successively: CMM fundamental imaging; CMM tissue harmonic imaging; tissue harmonic imaging cineloops for AMM; and fundamental imaging cineloops for AMM. Quantitative analysis was performed offline. The angle alpha between the CMM line and the septal endocardial interface was calculated and the expected percentage of error in measuring left ventricular diameter was derived. RESULTS: AMM analysis was reproducible. Optimal AMM full echocardiographic definition was obtainable in 77% of the population, whereas CMM was optimal for 49% because of scan line misalignment, causing a measurement overestimation exceeding 5%. CONCLUSION: The ability with AMM to reduce the alpha angle to 0 degrees and, thus, avoid overestimation of left ventricular dimensions might improve follow-up in several pathologic conditions.

Adolescent↗

PubMed2003

Experimental study of laminar blood flow through an artery treated by a stent implantation: characterisation of intra-stent wall shear stress.

The stimulation of endothelial cells by arterial wall shear stress (WSS) plays a central role in restenosis. The fluid-structure interaction between stent wire and blood flow alters the WSS, particularly between stent struts. We have designed an in vitro model of struts of an intra-vascular prosthesis to study blood flow through a 'stented' section. The experimental artery consisted of a transparent square section test vein, which reproduced the strut design (100x magnifying power). A programmable pump was used to maintain a steady blood flow. Particle image velocimetry method was used to measure the flow between and over the stent branches, and to quantify WSS. Several prosthesis patterns that were representative of the total stent strut geometry were studied in a greater detail. We obtained WSS values of between -1.5 and 1.5Pa in a weak SS area which provided a source of endothelial stimulation propitious to restenosis. We also compared two similar patterns located in two different flow areas (one at the entry of the stent and one further downstream). We only detected a slight difference between the weakest SS levels at these two sites. As the endothelial proliferation is greatly influenced by the SS, knowledge of the SS modification induced by the stent implantation could be of importance for intra-vascular prostheses design optimisation and thus can help to reduce the restenosis incidence rate.

Arteries↗

PubMed2003

Determination of the optimal region for interaliasing distance measurement for flow regurgitant rate calculation: a fluid simulation study.

BACKGROUND: Color Doppler imaging of the convergent region is promising for quantifying valvular regurgitation. Nevertheless, proximal isovelocity surface area method has limitations. We sought to determine the optimal localization to measure the most precise flow rate using a new approach: the interaliasing distance. METHODS: A finite volume-based program was used to perform simulations in unsteady flow conditions. Different instantaneous flow rates, leaflet angles, and orifice sizes were tested reproducing physiologic conditions. Relative difference between actual and interaliasing distance flow rate was calculated for each configuration. RESULTS: The relationship between the relative error and the aliasing velocity location was described by a third-order polynomial equation. The magnitude of relative error is a function of the flow rate, orifice size, and leaflet angle. CONCLUSION: The optimal distance from the orifice to measure the interaliasing distance was when the closer aliasing was between 4 and 8 mm from the orifice.

Atrial Function↗

PubMed2002

Noninvasive assessment of cardiac resynchronization therapy for congestive heart failure using myocardial strain and left ventricular peak power as parameters of myocardial synchrony and function.

INTRODUCTION: Although invasive studies have shown that cardiac resynchronization therapy by biventricular pacing improves left ventricular (LV) function in selected heart failure patients, it is impractical to apply such techniques in the clinical setting. The aim of this study was to assess the acute effects of cardiac resynchronization therapy by noninvasive techniques. METHODS AND RESULTS: Twenty-two patients enrolled in the InSync trial (age 64 +/- 9 years, 18 men and 4 women; all with ejection fraction < 35% and QRS > 130 msec) were studied 1 to 12 months after pacemaker implantation during pacing, and while ventricular pacing was inhibited. Regional myocardial strains of the interventricular septum, LV free wall, and right ventricular free wall were derived from color Doppler tissue echocardiography. Peak power index was calculated as a product of simultaneously recorded noninvasive blood pressure and pulse-wave (PW) Doppler velocity of the LV outflow tract. The Z ratio (sum of LV ejection and filling times divided by RR interval) and tei index were calculated from PW Doppler data. During pacing, overall regional strain improved (P = 0.01), while the LV strain coefficient of variation decreased from 2.7 +/- 2.4 to 1.3 +/- 0.7 (P = 0.009). Additionally, peak power index improved from 84 +/- 24 to 94 +/- 27 cm x mmHg/sec (P = 0.004). The Z ratio increased from 0.71 +/- 0.08 to 0.78 +/- 0.07 (P = 0.0005), while the tei index decreased from 0.86 +/- 0.33 to 0.59 +/- 0.16 (P = 0.0002). CONCLUSION: Using novel noninvasive indices, we demonstrated that cardiac resynchronization therapy improves LV performance.

Aged↗

PubMedDate not supplied

Prospective comparison of minimally invasive and standard techniques for aortic valve replacement: initial experience in the first hundred patients.

BACKGROUND: Aortic valve replacement (AVR) can be performed through a partial upper sternotomy. In this study we compared the early postoperative outcome in two groups of patients who underwent AVR with a minimally invasive procedure (n = 30) or with a conventional approach (n = 70). The predicted operative mortality (Parsonnet Index) was slightly higher in the conventional group (17.69 +/- 0.85 versus 12.7 +/- 1.02), reflecting the greater mean age of the patients (70.96 +/- 1.17 versus 64.20 +/- 2.57). RESULTS: The distribution of the different etiologies of aortic valve pathology did not differ between groups. There was no postoperative death in the mini-invasive group. Cardiopulmonary bypass time was longer in the mini-invasive group, but the other operative parameters did not differ between groups. Postoperative morbidity regarding the need for blood transfusion, the duration of assisted ventilation, length of stay in the intensive care unit, and abnormalities of cardiac rhythm and conduction was slightly but not significantly reduced in the mini-invasive group. CONCLUSIONS: Our data demonstrate that a partial upper sternotomy is a safe and effective technique for AVR. Postoperative morbidity is not significantly reduced in patients undergoing AVR by this approach. Further studies in a larger patient population are necessary to assess whether postoperative morbidity is significantly reduced.

Aged↗