Biomedical subjects
Publications and source records attributed to B Diébold.
The visualization of contrast agents in echocardiography is obtained with complex acquisition sequences and their analysis is dependent on operator experience. In order to be more accessible, images analysis is essential and the main objective is to integrate qualitative and quantitative data in one single image.
We aimed to characterise the alterations of left ventricular twist during ischaemia-reperfusion and to study their relationship to global left ventricular function. Systolic left ventricular twist was measured at the mid-papillary muscle level by colour tissue Doppler echocardiography in 7 anaesthetised open-chest dogs at baseline, 90 min-occlusion of the left anterior descending, and 180 min after reflow. Tissue Doppler was also performed in 34 patients after anterior infarct and in 20 controls. In controls, rotation occurred counterclockwise when viewed from the base. In a random subset of subjects, the assessment of ventricular twist by tissue Doppler was validated against magnetic resonance myocardial tagging. Myocardial ischaemia led to a decrease in ventricular twist in dogs and infarct patients (p < 0.01). This decrease was correlated with the extent of the asynergic area and global left ventricular function (p < 0.001). In dogs, cardiac twist was higher after reflow relative to ischaemia (p < 0.01). Thus, acute myocardial ischaemia is responsible for a decrease in left ventricular twist that is related to global ventricular function. Colour tissue Doppler echocardiography provides straightforward assessment of left ventricular twist in humans.
OBJECTIVES: The goal of this research was to study coronary atherosclerosis in patients with type 2 diabetes compared with patients without diabetes according to the new definition of diabetes advocated by the American Diabetes Association in 1997. BACKGROUND: Patients with diabetes (fasting plasma glucose above 7.0 mM/L) have a higher risk of cardiovascular death. The correlation with the pattern and severity of their coronary atherosclerosis, especially in the new patients with "mild" diabetes (7.0 mM/L < or = fasting plasma glucose < 7.8 mM/L), remains unclear. METHODS: A cohort of 466 patients undergoing coronary angiography but free of any previous infarction, coronary intervention and insulin therapy were prospectively recruited. Ninety-three had diabetes (fasting plasma glucose > 7.0 mM/L or hypoglycemic oral treatment). Five angiographic indexes were calculated to describe severity and extent of coronary atherosclerosis. RESULTS: Overall, patients with diabetes had more diffuse coronary atherosclerosis, a greater prevalence of mild, moderate and severe stenoses and a two-fold higher occlusion rate than patients without diabetes, even after adjustment for age, gender, body mass index, hypertension, lipid parameters, smoking, family history of cardiovascular events and ischemic symptoms. Patients with "mild diabetes" had a coronary atherosclerosis pattern more similar to patients with normal fasting plasma glucose than to patients formerly defined as diabetic according to the World Health Organization criteria, except that they had a higher prevalence of <50% stenoses. CONCLUSIONS: In patients with type 2 diabetes, those with 7.0 mM/L < or = fasting plasma glucose < 7.7 mM/L have a slightly greater prevalence of mildly severe lesions that may partly explain their higher cardiovascular event rate.
Myocardial ischemia is usually responsible for alterations of regional left ventricular function which are not quantified by routine echocardiography. We used tissue Doppler echocardiography to quantitate the three main components (radial, longitudinal and angular) of left ventricular function, and their alterations after acute anterior myocardial infarction. Radial function was assessed by the myocardial velocity gradient derived from M-mode color tissue Doppler echocardiography, and longitudinal function by the pulsed wave tissue Doppler echocardiography, in 26 patients who experienced a first acute anterior myocardial infarction and in 11 matched healthy subjects. We describe a new tissue Doppler method for the measurement of septal angular deformation during cardiac contraction. In healthy subjects, our results showed heterogeneous regional myocardial contraction. Septal angular deformation occurred in the same direction and was of the same order as predicted by previous MRI studies. After anterior infarction, systolic and diastolic myocardial velocity gradients were dramatically decreased in the anterior wall when compared with controls (p < 0.01), whereas the systolic velocity gradient was significantly higher in the opposite wall (p < 0.05). Pulsed wave tissue Doppler echocardiography revealed significant alterations of longitudinal left ventricular function. Septal angular deformation was decreased after anterior infarct, and a good correlation was found between the angle of rotation and the left ventricular ejection fraction by cineangiography. These results indicate that tissue Doppler echocardiography has the potential for measuring the three main components of regional left ventricular function, and for quantitatively assessing their functional alterations induced by acute myocardial ischemia.
OBJECTIVES: We sought to identify the angiographic predictors of a future infarction, to study their interaction with time to infarction, patient risk factors and medications, and to evaluate their clinical utility for risk stratification. BACKGROUND: Identification of coronary lesions at risk of acute occlusion remains challenging. Stenosis severity is poorly predictive but other stenosis descriptors might be better predictors. METHODS: Eighty-four patients with an acute myocardial infarction and a coronary angiogram performed within the preceding 36 months (baseline angiogram), and after infarction were selected. All coronary stenoses (from 10% to 95% lumen diameter reduction) at baseline angiogram were analyzed by computer-assisted quantification. Each of the 84 lesions responsible for the infarction (culprit) was compared with the nonculprit stenoses (controls) in the same patient. RESULTS: Culprit lesions were more symmetrical (symmetry index +15%; p < 0.001), had steeper outflow angles (maximal angle +4 degrees; p < 0.001), were more severe (percent stenosis +5%; p = 0.001) and longer (+ 1.5 mm, p = 0.01) than controls. The symmetry index and the outflow angles were the two independent predictors of infarction at three-year follow-up. Stenosis severity predicted only infarctions occurring within 1 year after angiography. In moderately severe stenoses (40% to 70% stenosis), stratification using the symmetry index and outflow angles accurately predicted lesions remaining free of occlusion and infarction at three-year follow-up. CONCLUSIONS: Better characterization of stenosis geometry might help to understand the pathophysiologic mechanisms triggering coronary occlusion and to stratify patients for improved care.
Left ventricular (LV) systolic function is partly determined by severity of coronary artery disease and is improved by angiotensin-converting enzyme (ACE) inhibition, at least in post-infarct patients. Because the ACE insertion/deletion (I/D) gene polymorphism is associated with circulating and tissue ACE activity, we sought to evaluate the role of this genetic variant on LV function in patients studied with coronary angiography, taking into account coronary vessel anatomy and history of infarction. Coronary artery disease extent scores, coronary artery patency, and LV ejection fraction were assessed in 400 consecutive Caucasian patients referred for established or suspected ischemic heart disease. A previous infarction had occurred in 141 patients an average of 3.7 years before the study. The ACE DD genotype, compared with the ACE ID/II genotype, was associated with a 2.7% higher ejection fraction in noninfarct patients (p = 0.047) but a 5.0% lower ejection fraction in post-infarct patients (p = 0.047). An interaction effect between the ACE I/D gene polymorphism, the infarction status, and LV ejection fraction was observed in the whole population (p = 0.003), in patients with no disease and 1-, 2-, and 3-vessel diseases (p = 0.03 and p = 0.06, respectively), and in those with chronically occluded coronary vessels (p = 0.02). The influence of the ACE I/D gene polymorphism on LV function is modulated by infarction status and coronary anatomy.
OBJECTIVE: To compare the 2-year longitudinal with the cross-sectional relationships of blood pressure and body mass index with echocardiographic left ventricular measurements in middle-aged males with no history of cardiovascular disease or hypertension. METHODS: M-mode echocardiograms of adequate quality were obtained at initial and 2-year follow-up examinations in 177 subjects. Measurements of left ventricular wall thickness and internal dimensions were made, and estimates of left ventricular mass/height were calculated. Longitudinal changes in left ventricular measurements and risk factors were computed as the differences between the follow-up and initial values. RESULTS: Systolic blood pressure (SBP) was significantly associated with left ventricular mass/height and wall thickness in cross-sectional and in longitudinal analyses. Similar results were observed after adjusting for age, body mass index, sport activity and heart rate. Although body mass index was strongly related to left ventricular mass/height, wall thickness and internal dimension in the cross-sectional study, no significant associations were observed between changes in body mass index and in left ventricular measurements. CONCLUSIONS: The present study emphasizes the differential effects of spontaneous changes in blood pressure and body mass index on the evolution of the left ventricular mass in middle-aged males. Spontaneous changes in SBP during the 2-year follow-up period were associated with rapid changes in left ventricular structure. The 2-year period might not have been sufficient for body mass index to induce changes in left ventricular structure. The duration and amplitude of body weight changes which entail changes in left ventricular mass remain to be determined by further longitudinal investigations.
The human thoracic aorta is usually considered to be a purely elastic vessel. Transoesophageal echo-cardiography (TEE) provides a new approach to study the mechanical properties of the descending aorta. The aim of the study was to evaluate the reproducibility and accuracy of M mode recordings of the human descending thoracic aorta and to appreciate the changes produced by an infusion of glyceryl trinitrate (GTN). The reproducibility of M mode recordings was studied in vitro on plexiglass tubes of different calibre, and also in vivo, the inter and intra-observer error was estimated to 0.6% in vitro and 1% in vivo. The accuracy of the method was evaluated in vitro by comparing the measured values (MV) with the actual diameters of the plexiglass tubes (T): MV = 1.012T + 0.9; r = 0.99; SE = 0.8 mm. The systolic and diastolic diameters of the descending thoracic aorta were measured in 8 healthy volunteers by TEE, before and during continuous intravenous infusion of GTN at a rate of 0.9 mg/hr and then 1.35 mg/hr after a 10 minutes interval. Systolic and diastolic blood pressures were recorded automatically every minute. The results showed a very significant increase in the systolic (from 20.3 +/- 0.7 to 20.9 +/- 1.3 and 22.1 +/- 2.2 mm) and diastolic diameters of the aorta (from 18.3 +/- 0.7 to 19.1 +/- 1.4 and 20.1 +/- 2.4 mm) despite a fall in systolic blood pressure (from 121.3 +/- 7.7 to 114.5 +/- 6.6 and 108.4 +/- 5.4 mmHg). This study shows that TEE is a reliable and reproducible method of measuring the diameter of the human descending thoracic aorta.(ABSTRACT TRUNCATED AT 250 WORDS)
The authors report the first case of lethal cerebral embolism complicating thrombolytic therapy administered for thrombosis of a mitral valve prosthesis. The incidence of systemic embolism during this form of therapy appears to be at least one in five cases. It may be underestimated and should lead to further discussion as to the indications of thrombolytic therapy and surgery for thrombosis of a left heart valve prosthesis.
The reliability of pulsed Doppler echocardiography in the diagnosis and quantification of tricuspid regurgitation was assessed by analysis of blood flow in the inferior vena cava in 28 patients. The inferior vena caval flow was sampled in the retrohepatic portion of the vessel from the subxiphoid region. Recordings from 10 normal patients were used to define criteria of normality. This was characterised by two anterograde components (one systolic and one diastolic); atrial contraction gave rise to an end diastolic retrograde component. In tricuspid incompetence, retrograde systolic blood flow was recorded. A Doppler index was calculated from the ratio of the maximal amplitude of systolic reflux to the maximal amplitude of anterograde diastolic flow. In the absence of tricuspid regurgitation, this index approximated 0. The average of this ratio over 10 consecutive beats was compared with the semi quantitative assessment of tricuspid regurgitation from selective right ventricular angiography. There were no false positive results, specificity was, therefore, 100 p. 100. Six minimal regurgitations were not detected: sensitivity was therefore 74 p. 100. All moderate and severe regurgitations were detected, and the sensitivity for these cases was 100 p. 100. There was a close correlation (R = 0,89, p less than 0,01) between the Doppler index and the degree of regurgitation assessed by selective right ventricular angiography.