Biomedical subjects

Olivier Pascal

Publications and source records attributed to Olivier Pascal.

5 recordsLinked to original sources

PubMed2005

Myocardial contractility is early affected in systemic sclerosis: a tissue Doppler echocardiography study.

AIMS: Systemic sclerosis (SSc) is a connective tissue disorder characterized by frequent myocardial involvement. Alteration in left ventricular (LV) function is reported to be rare; however, it may be underestimated by conventional measurements. Our aim was to prospectively investigate LV function in SSc patients, using Tissue Doppler echocardiography (TDE), a modern and accurate method of assessing myocardial function. METHODS AND RESULTS: Seventeen consecutive SSc patients with normal cardiac examination, pulmonary artery pressure (PAP) and radionuclide LV ejection fraction (EF) were prospectively investigated. Myocardial perfusion was investigated using single-photon-emission computerized tomography (SPECT). Echocardiography (ECHO), systolic and diastolic strain-rate (SR) measured in the posterior wall by TDE were used to investigate myocardial function, and compared with results of 15 matched controls. All patients (53+/-8 years; 14 women; systolic PAP 33+/-6 mmHg; LVEF 67+/-8%) had myocardial SPECT perfusion abnormalities. Despite normal ECHO, they had lower systolic SR than controls (1.7+/-0.5 versus 3.8+/-1.7 cm-1, p<0.0001), and lower diastolic SR (3.7+/-1.5 versus 5.6+/-1.2 cm-1, p=0.0004). Ten SSc patients had reduced systolic SR<1.7 cm-1 and 11 reduced diastolic SR<3.5 cm-1. CONCLUSION: Frequent abnormal myocardial perfusion is confirmed in SSc patients. Reduced contractility is also frequent as detected by TDE, despite normal radionuclide LVEF.

Blood Flow Velocity↗

PubMed2003

Usefulness of combined quantitative assessment of myocardial perfusion and velocities by myocardial contrast and doppler tissue echocardiography during coronary blood flow reduction.

OBJECTIVES: We sought to characterize regional myocardial perfusion and contraction in a closed-chest swine model during and after coronary blood flow reduction using myocardial contrast and Doppler tissue echocardiography. METHODS AND RESULTS: Regional myocardial perfusion was assessed by myocardial contrast echocardiography using the corrected contrast peak intensity (baseline-subtracted contrast peak intensity), the peak intensity ratio (contrast peak intensity in ischemic/control wall), and a transmural video-intensity gradient. Regional peak systolic velocities and strain rate were measured using M-mode color Doppler tissue echocardiography. In 12 pigs, coronary blood flow reduction resulted in a significant decrease in peak intensity ratio and in peak systolic velocities in the subendocardium. At baseline and during ischemia, corrected contrast peak intensity and peak systolic velocities in the subendocardium, video-intensity gradient, and strain rate were closely related (r = 0.88 and 0.93, respectively). After reperfusion, in contrast to peak systolic strain rate that remained altered, the peak intensity ratio and video-intensity gradient recovered nearly baseline values. CONCLUSION: The combination of myocardial contrast and Doppler tissue echocardiography may distinguish between ischemic and postischemic myocardial wall dysfunction during severe coronary blood flow reduction.

Animals↗

PubMed2002

Time course and relation to local viability of microvascular function and volume after reperfused acute myocardial infarction.

We assessed the time course of the alterations of microvascular function and myocardial perfusion, as well their relation to local inotropic reserve (IR), in 21 patients who underwent successful primary coronary angioplasty for acute myocardial infarction and in whom local myocardial dysfunction persisted at hospital discharge. Coronary flow reserve (CFR) and myocardial perfusion were assessed immediately after angioplasty, and on day 1 and day 8 by intracoronary Doppler and myocardial contrast echocardiography, respectively. Dobutamine echocardiography was performed on day 7 for assessment of local IR. After angioplasty, CFR was severely altered in patients with (n = 14) and without (n = 7) IR (1.44 +/- 0.26 and 1.36 +/- 0.21, respectively; p = NS). Among patients with IR, CFR increased significantly at day 1 (2.26 +/- 0.62, p <0.005 vs acute stage) compared with those without IR (p = NS vs acute). In contrast, the extent of microvascular obstruction as defined by contrast echocardiography remained unchanged in all patients at day 1 compared with acute measurements. Microvascular obstruction decreased at day 8 in the sole subset of patients with local IR (p <0.05 vs acute stage). In patients treated by immediate coronary angioplasty for acute myocardial infarction, subsequent improvement of myocardial perfusion is associated with preexistent recruitable microvascular function in the infarct-related artery. The presence of reversible microvascular dysfunction at the early stage after acute myocardial infarction is associated with local tissue viability in humans.

Aged↗

PubMed2002

Characterization of peripheral arterial wall motion by Doppler tissue echography: a validation study.

Doppler tissue echography (DTE) has been proposed for arterial wall-motion analysis. However, it is not known if DTE gives precise measurements of arterial displacement. Therefore, we used a pig aorta, in vitro model to study arterial wall velocities. High resolution color B-mode DTE acquisitions gave accurate estimations of velocities as compared with those obtained by a referenced wall-tracking system, with a slight underestimation of values calculated from DTE (14.4 +/- 0.1 for DTE vs 16.1 +/- 0.2 at 5 L/min output, P >.05). Excellent correlations were obtained between both methods (r(2) = 0.94, P <.001), and Bland-Altman analysis revealed no significant differences between measurements. We also compared common carotid arterial wall velocities obtained in 16 healthy volunteers by DTE and a wall-tracking system, which gave similar wave profiles. As expected, arterial distensions calculated from DTE were lower than those from a wall-tracking system (6.8 +/- 1.7% vs 7.4 +/- 2.1%, respectively, P =.02). These results indicate that DTE may be used to study arterial wall displacement.

Adult↗

PubMed2002

Alterations of systolic left ventricular twist after acute myocardial infarction.

We sought to characterize the alterations of left ventricular (LV) twist after acute myocardial infarction in humans and to study their relationship to usual parameters of LV function. Systolic LV twist was measured by color tissue Doppler echocardiography (TDE) in 34 patients after anterior myocardial infarction and in 20 controls. In a subset of controls and patients, the assessment of LV twist by TDE was validated against magnetic resonance (MR) tissue tagging with good agreement between the two methods. Myocardial ischemia was responsible for a decrease in LV twist in infarct patients (P < 0.01). The decrease in LV twist was correlated with the extent of the asynergic area and global LV function as assessed by LV cineangiography (P < 0.001). Thus acute myocardial ischemia is responsible for a decrease in LV twist that is related to global LV function. Color TDE is a promising technique for straightforward assessment of LV twist in humans.

Acute Disease↗