Biomedical subjects

Pascal Gueret

Publications and source records attributed to Pascal Gueret.

10 recordsLinked to original sources

PubMed2006

Influence of preoperative left ventricular contractile reserve on postoperative ejection fraction in low-gradient aortic stenosis.

BACKGROUND: Dobutamine stress hemodynamics (DSH) has the potential to stratify operative risk in low-gradient aortic stenosis (AS), but little is known about the relation between left ventricle contractile reserve and postoperative left ventricular ejection fraction (LVEF). We sought to assess the value of DSH to predict postoperative improvement in LVEF. METHODS AND RESULTS: Sixty-six consecutive patients with symptomatic severe AS (aortic valve area < or =1 cm2), LVEF < or =40%, and mean pressure gradient < or =40 mm Hg prospectively enrolled in the French multicenter study on low-gradient AS and who survived to aortic valvular replacement (AVR) were included. Preoperative contractile reserve was present in 46 patients (group I; 70%) and absent in 20 patients (group II; 30%). In the overall sample, 58% of patients improved by 2 New York Heart Association (NYHA) classes after AVR. Mean LVEF improved from 29+/-6% to 47+/-11% (P<0.0001). LVEF improved by > or =10 EF units in 38 patients (83%) in group I and in 13 patients (65%) in group II. Mean LVEF improvement was similar in the 2 groups (19+/-10% versus 17+/-11%; P=0.54). On multivariable analysis, multivessel coronary artery disease (P=0.05) and baseline mean transaortic pressure gradient (P=0.01) were related to LVEF improvement, whereas contractile reserve was not. CONCLUSIONS: LVEF increases in the majority of patients with low-gradient AS who survive after AVR. Although the absence of contractile reserve on DSH is related to high operative mortality, it does not predict the absence of LVEF recovery in patients surviving to AVR. These data further support the concept that surgery should not be contraindicated on the basis of absence of contractile reserve alone.

Aged↗

PubMed2005

Functional assessment of mitral regurgitation by transthoracic echocardiography using standardized imaging planes diagnostic accuracy and outcome implications.

OBJECTIVES: We sought to assess the value of transthoracic echocardiography (TTE) using standardized imaging planes for the functional analysis of mitral regurgitation (MR) as well as for postoperative outcome implications. BACKGROUND: The feasibility of mitral valve repair is based on functional assessment of MR, mainly by transesophageal echocardiography (TEE). Considering the recent advances in TTE imaging, the incremental value of TEE in this setting needs to be re-examined. METHODS: Consecutive patients (n = 279; 181 men; median age 68 years [quartiles, 61 to 74]) who underwent surgery for MR were enrolled prospectively in two tertiary care centers. The accuracy of TTE (harmonic imaging) versus TEE for functional assessment of MR was evaluated against surgical findings. RESULTS: Valve repair (n = 237 patients, 85%) or replacement (n = 42) was predicted accurately by TTE in 97% of cases; TEE added significant information for only two patients. In the subgroup of degenerative MR (n = 190), agreement with surgical findings for the localization of prolapsed segments was 91% for TTE (kappa, 0.81) and 93% for TEE (kappa, 0.85) without incremental value of TEE (p = 0.40). Patients with single prolapse of the middle posterior scallop (P2) had a better postoperative outcome as compared with patients who had non-P2 lesions (p = 0.008). Furthermore, mitral replacement predicted by TTE was an independent predictor for postoperative long-term mortality (odds ratio 5.7, 95% confidence interval 1.97 to 16.4, p = 0.001). CONCLUSIONS: In experienced hands, functional assessment of MR by TTE can predict accurately valve repairability and has a strong influence on postoperative outcome. Thus, in most cases preoperative TEE is not mandatory, provided intraoperative TEE is performed.

Aged↗

PubMed2004

Relationship between the ischemic threshold at the onset of wall-motion abnormality on semisupine exercise echocardiography and the extent of coronary artery disease.

Semisupine exercise echocardiography (SSEE) provides the unique opportunity of continuous monitoring of segmental wall motion during physiologic stress. We evaluated the relationship between the ischemic threshold at the onset of wall-motion abnormality on SSEE and the extent of coronary artery disease (CAD) in a consecutive series of 224 patients who underwent coronary angiography. Ischemic threshold was significantly lower for patients with multivessel disease compared with single-vessel disease: maximal workload was 102 versus 135 W (P = 1.3.10(-6)); percentage of maximal predicted heart rate achieved was 64 versus 70% (P =.004); and double product was 21,335 versus 23,389 (P =.03), respectively. Sensitivity, specificity, and positive and negative predictive values of SSEE for the detection of significant CAD (> or =60% diameter stenosis) were 81%, 74%, 90%, and 56%, respectively. SSEE is an accurate tool to diagnose CAD and the ischemic threshold at the onset of wall-motion abnormality is inversely related to the extent of CAD.

Adult↗

PubMed2004

Predictors of outcome in patients with severe aortic stenosis and normal left ventricular function: role of B-type natriuretic peptide.

AIMS: B-type Natriuretic Peptide (BNP) is activated in patients with severe, symptomatic aortic stenosis (AS), but the prognostic value of BNP in this setting has not been extensively studied. This study aimed to assess the prognostic value of the BNP level in symptomatic and asymptomatic patients with severe AS. METHODS: Seventy consecutive patients referred to our echocardiography laboratory for severe AS with preserved left ventricular function were prospectively enrolled (40 men, median age 74 years [62-82]; aortic valve area 0.7 cm2 [0.6-0.8]; transaortic gradient 48 mmHg [38-60], and left ventricular fractional shortening 38% [32-43]). C-terminal BNP serum level at enrollment was evaluated against baseline functional and echocardiographic parameters as well as clinical outcome. RESULTS: BNP level was elevated in the presence of symptoms and increased with NYHA functional class. BNP serum level >66 pg/ml detected symptomatic patients with a sensitivity, specificity and accuracy of 84%, 82% and 84%, respectively. In symptomatic and asymptomatic patients, BNP level was a strong independent predictor for cardiovascular death by multivariable analysis adjusted to age and NYHA functional class. CONCLUSIONS: BNP serum level allows to differentiate symptomatic from asymptomatic patients with severe AS. BNP is an independent predictor of outcome in these patients and may be helpful for risk stratification.

Aged↗

PubMed2004

Assessment of myocardial reperfusion after myocardial infarction using automatic 3-dimensional quantification and template matching.

UNLABELLED: Assessment of perfusion defect extent is essential for determining prognosis after a myocardial infarction (MI), but quantification methods usually rely on segmental analysis, which may lack accuracy. We present an automated voxel-based and template-based approach for precise quantification of perfusion defect extent and reperfusion evolution. METHODS: Coronary angiography and stress/reinjection (201)Tl tomography were performed prospectively on 49 patients with recent MI (45 men; mean age +/- SD, 54 +/- 10 y), before and 3 mo after revascularization (40 angioplasties and 9 bypasses). Perfusion defect extent was quantified using expert 16-segment visual scoring of the slices and a 3-dimensional (3D) method with spatial normalization between times 1 and 2. Briefly, the latter automatically extracted myocardial edges, matched them to a reference template, and compared the perfusion intensity in each voxel with the intensity of the corresponding voxel in a control population of 100 healthy subjects. RESULTS: Reocclusion occurred in 12 patients within 3 mo of surgery (all had undergone angioplasty). The perfusion gain between times 1 and 2, assessed by visual analysis, was significantly higher in permeable patients than in reoccluded patients: 12.4% +/- 13.3% and 2.3% +/- 8.2% of the initial stress defect, respectively (P = 0.02). Proportional gains, measured with the quantitative 3D method, were 4.5% +/- 3.6% and 1.9% +/- 2.7%, respectively (P = 0.02). Furthermore, the 3D method allowed measurement within the initial ischemic defect (reversible part of the stress defect at time 1), the extent of myocardium whose perfusion improved at time 2 (reperfusion), and the extent of myocardium whose perfusion remained unchanged (residual ischemia). A voxel-by-voxel analysis of these regions revealed that the proportion of reperfusion was significantly higher in permeable patients than in reoccluded patients: 60.0% +/- 21.3% versus 40.0% +/- 22.5%, respectively (P = 0.008). This was cumbersome to quantify using visual analysis and did not reach statistical significance, likely because of segmental division (partial-volume effect) and absence of spatial normalization. CONCLUSION: The 3D voxel-based quantification allows satisfying assessment of reperfusion 3 mo after MI. Moreover, the automated analysis using spatial normalization should facilitate a reproducible assessment of large populations over time.

Aged↗

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↗

PubMed2003

Regression of left ventricular hypertrophy with echocardiography: some lessons from the LIVE study.

OBJECTIVE: Large trials on left ventricular hypertrophy (LVH) regression are indispensable to allow accurate evaluation of the different classes of treatments. Such a trial, the LIVE study, gave us the opportunity to examine the influence of the mode of reading of the echo tracings on results and to underline the value of two initial recordings performed at entry. METHODS: The LIVE study was designed to compare 1.5 mg indapamide SR with 20 mg enalapril on the regression of LVH evaluated echocardiographically. M-mode tracings of the left ventricle were performed at selection and after a 2 week placebo run-in. Recordings were read by investigators and by three experts all through the study, and finally read again by the three experts blind to treatment and sequence. RESULTS: The two initial examinations produced an estimate of the reproducibility of the measurement of the left ventricular mass (LVM) that can be proposed as an indicator of overall quality provided no patients are excluded. The standard deviation of the differences between these two estimates of LVM was 52 g. These two examinations may also help quantify regression to the mean, which was not significant for the whole group. Knowledge of the sequence of examinations overestimates the change in LVM with treatment, as shown by comparison of measurements carried out during quality control with the measurements made blind (-19 +/- 52 versus -6 +/- 53 g, P <0.01). CONCLUSIONS: The comparison of two initial echoes at entry allow one to define a quality criteria for such trials and to quantify a possible regression to the mean. The reading of recordings with knowledge of sequence significantly overestimates LVM variations on treatment.

Antihypertensive Agents↗

PubMed2003

Development of congestive heart failure in type 2 diabetic patients with microalbuminuria or proteinuria: observations from the DIABHYCAR (type 2 DIABetes, Hypertension, CArdiovascular Events and Ramipril) study.

OBJECTIVE: The DIABHYCAR (type 2 DIABetes, Hypertension, CArdiovascular Events and Ramipril) study allowed investigators to analyze factors leading to the development of congestive heart failure (CHF) in type 2 diabetic patients with abnormal urinary albumin concentration. RESEARCH DESIGN AND METHODS: Type 2 diabetic subjects of both sexes aged >or=50 years who had a urinary albumin concentration >or=20 mg/l were randomly allocated to 1.25 mg/day ramipril or placebo in addition to their usual treatment and treated for 3-6 years in a double-blind fashion. Major outcomes including hospitalization for CHF were recorded during the follow-up. RESULTS: Of the 4912 included patients, 187 developed CHF during the study. There was no significant difference in the incidence of CHF between the two treatment groups. Using a multivariate analysis, independent risk factors for the occurrence of CHF were age, history of cardiovascular disease, baseline urinary albumin concentration, baseline HbA(1c), and smoking habits. A total of 68 of the 187 patients (36.4%) died during the 12 +/- 11-month period after the first hospitalization for CHF, whereas the annual mortality rate of the population who did not develop CHF was 3.2%. CONCLUSIONS: Presence of atherosclerotic disease, baseline urinary albumin concentration, and HbA(1c) level were indicators for further development of CHF. Occurrence of CHF is a major prognostic turn in a diabetic patient's life.

Aged↗

PubMed2002

Evaluation of carotid artery and aortic intima-media thickness measurements for exclusion of significant coronary atherosclerosis in patients scheduled for heart valve surgery.

OBJECTIVES: We assessed the value of carotid intima-media thickness (CIMT) and thoracic aorta intima-media thickness (AoIMT) in ruling out significant coronary artery disease (CAD) in patients scheduled for heart valve surgery. BACKGROUND: Evaluation of CAD is needed in most patients undergoing heart valve surgery because of the high surgical morbidity in patients with significant CAD, raising the need for sensitive tests to exclude CAD. Coronary angiography is the reference standard, but this invasive procedure is not cost-effective, because more than two-thirds of these patients do not have significant CAD. METHODS: In a pilot study, CIMT and AoIMT cutoff values separating low- from high-risk groups were determined in 96 patients by using receiver-operating characteristic curves. Then, a prospective study was conducted in 152 patients to determine the statistical power of these cutoff values used alone or in combination. In both studies, carotid artery ultrasonography and transesophageal echocardiography were performed before coronary angiography and valve surgery. RESULTS: In the pilot study, CIMT < 0.55 mm and AoIMT < 3 mm were excellent predictors of the absence of CAD. In the prospective study, CIMT and AoIMT criteria were independent predictors of significant CAD in these patients, as assessed by logistic regression analysis. Carotid IMT criterion had 100% sensitivity and 100% negative predictive value. For the AoIMT criterion, sensitivity was 98%, and negative predictive value 99%. Combining the two criteria did not change sensitivity and negative predictive value but increased specificity to 78%. CONCLUSIONS: Measurements of CIMT and AoIMT may be useful in selecting patients who do not require coronary angiography before heart valve surgery.

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↗