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Biomedical subjects

M Dahan

Publications and source records attributed to M Dahan.

At least 73 records · Page 4Linked to original sources
PubMed1994

[Abnormal peripheral circulation in heart failure].

Left ventricular failure leads to circulatory failure which causes clinical symptoms and in which regional blood flow changes play an important role. An abnormality of systemic vasodilatation on exercise or on pharmacological intervention has been shown. This affects both the resistance and conductive vessels and is mainly functional, related to neurohormonal stimulation with a predominance of vasoconstrictive factors amongst which increased adrenergic tone probably plays an essential part. A modification of the endothelium-dependent response has recently been confirmed. The presence of structural vascular abnormalities (increase in parietal sodium and water concentrations, "remodelling" remains debatable in the human. These abnormalities have a common factor in their chronicity and take time to regress with medical treatment or after cardiac transplantation. Physical training seems to induce more marked and, above all, more rapid effects.

Endothelium, Vascular↗
PubMed1993

Late thrombotic obstruction of an aortic bioprosthetic valve: successful treatment by oral anticoagulation.

Thrombotic obstruction of aortic bioprostheses is rare. Few cases have been reported involving the use of the Carpentier-Edwards (CE) prosthesis, the Hancock bioprosthesis, or the Medtronic Intact porcine valve. Thrombolytic therapy for mechanical valve thrombosis has been used frequently even though it is known to carry a high risk of embolism and recurrence. However, the use of this therapy was reported for the first time only recently, in a case of acute aortic thrombosis which occurred 3 1/2 months after bioprosthesis insertion. We report a case of late progressive thrombotic obstruction of a CE aortic valve 3 years after insertion. The case was successfully treated with coumadin therapy, as confirmed by serial Doppler echocardiographic examinations and a 3-year follow-up.

Aortic Valve↗
PubMed1993

Determinants of stroke volume response to exercise in patients with mitral stenosis: a Doppler echocardiographic study.

OBJECTIVES: The aim of this study was to assess exercise-induced changes in stroke volume and their main determinants in mitral stenosis. BACKGROUND: The mechanisms of the stroke volume response to exercise in mitral stenosis are not clearly established. METHODS: Twenty-seven patients with mitral stenosis, aged 47 +/- 13 years, and 10 healthy control subjects, aged 46 +/- 11 years, were examined by Doppler echocardiography to obtain stroke volume, mitral velocity-time integral and calculated mitral valve area (by continuity equation) at rest and during submaximal supine bicycle exercise. Measured mitral valve area at rest and total mitral score were also obtained. RESULTS: During exercise, stroke volume increased significantly (p < 0.001) in the control subjects (+25 +/- 6%) but remained unchanged in the patients. In 10 patients (Group I), stroke volume increased by > or = 14% (+23 +/- 10%, p < 0.001); in the other 17 (Group II), it decreased or increased by < 14% (-5 +/- 14%, p = NS). Mitral velocity-time integral did not change in the three groups, whereas calculated mitral valve area increased significantly (p < 0.001) and similarly in Group I and the control group but remained unchanged in Group II. The exercise change in calculated mitral valve area correlated significantly with both measured mitral valve area at rest (r = 0.46, p < 0.05) and total mitral score (r - 0.53, p < 0.005). However, at constant mitral score, exercise change in calculated mitral valve area no longer correlated significantly with measured mitral valve area at rest. CONCLUSIONS: In mitral stenosis, the change in stroke volume during exercise depends on the change in mitral valve area, which itself depends on the degree of mitral valve damage.

Blood Flow Velocity↗
PubMed1993

[Neurologic and psychiatric manifestations of primary hyperparathyroidism. Study of 5 cases].

Among 8 of the 20 records of primary hyperparathyroidism examined in search of neurological and/or psychiatric manifestations, the authors extracted 5 clinical cases reported here. These 5 cases were selected because these manifestations had been well evaluated before and after curative surgery of the disease. Among the manifestations reported, there was one corpus striatum syndrome, one cervical myelopathy and three cases of "chronic" psychiatric disorders of several years duration completely cured after parathyroidectomy. The authors underline that such psychiatric disorders should be taken into account in the discussion of treatment.

Adult↗
PubMed1993

Self-expandable prostheses in the tracheobronchial tree.

Under endoscopic and radiologic control, two types of self-expandable metal prostheses were implanted in tracheobronchial lesions to help reestablish airway caliber. Thirty-nine metal stent prostheses (6-20 mm in diameter) and 35 Gianturco stents (30 mm in diameter) were used in 55 adult patients with 62 lesions of the trachea (n = 33) or bronchi (n = 29). All lesions except one were endoscopically confirmed to be noninflammatory. Immediately after implantation, radiologic and endoscopic studies verified reestablishment of a satisfactory airway diameter in all patients. At a mean follow-up of 10.35 (range, 3-27) months, improvement in the respiratory status of 49 of the 55 patients (89%) was maintained and tolerance of the device was excellent. For the Wallstent endoprosthesis, the six complications observed at endoscopy were successfully treated. The Gianturco stent, however, led to a high rate of complications: 30% of cases had migration and/or rupture of the metallic mesh, potentially leading to obstruction or wall perforation; one case of respiratory distress was fatal. This procedure offers rapid epithelialization and incorporation of the device into the tracheobronchial wall.

Adult↗
PubMed1993

[Effects of aging on left ventricle-arterial coupling in man].

Twenty-five normotensive men without any cardiac or arterial pathology, aged 22 to 68 years, 12 less than 45 year old, 13 over 45 years, underwent cardiac catheterisation and angiography. The following parameters were calculated: 1) a global index of arterial function (Ea) and its determining factors (Ea = LVESP/SV where LEVSP = left ventricular end systolic pressure and SV = left ventricular stroke volume); Ea = (HR x SVR) + Ea' where HR = heart rate, SVR = total systemic vascular resistance and Ea' = (LVESP - MAP/SV) (MAP = mean arterial pressure); 2) an index of global left ventricular pump function: ELV (ELV = LVESP/LVESV, where LVEDV = left ventricular end systolic volume; 3) an index of LV-arterial coupling: the Ea/ELV ratio. With aging, both Ea (by increase in SVR) and Ea' and ELV increased significantly. Ea/ELV (inverse of the ejection fraction-1) increased with age but ELV less than Ea. Ea/ELV was significantly higher in patients over 45 years of age but the correlation between ejection fraction and age was not statistically significant (p = 0.10). These results suggest that with aging, the improvement in LV pump function approximately corresponds to the degradation in arterial transport function: the left ventricular-arterial coupling as assessed by the Ea/ELV ratio (and therefore the ejection fraction) is maintained in the majority of cases.

Adult↗
PubMed1993

[Doppler echocardiographic evaluation of physical properties of the aorta and left ventricular geometry in normotensive hemodialyzed patients].

Twenty-five patients undergoing hemodialysis therapy with a normal blood pressure (16 men, 9 women, age = 54 +/- 14 years) and 25 sex and age-matched healthy normotensive subjects were examined by doppler-echocardiography. Pulse wave velocity (PWV) in the thoracic descending aorta, diameter of the ascending aorta (AD), left ventricular mass (m), thickness-radius ratio (th/r), shortening fraction (SF), end systolic pressure-diameter ratio (P/D) and the ratio of late and early mitral velocity (A/E) were obtained. Pulse wave velocity, SF, P/D, were not significantly different in the 2 groups whereas AD, m, th/r, and A/E were significantly larger in dialysis patients than in controls (both, p < 0.001). These results indicate that in patients treated by hemodialysis with a normal blood pressure, a concentric left ventricular hypertrophy is associated with a normal aortic stiffness, suggesting a depressed myocardial contractility.

Adult↗
PubMed1992

[Functional coupling of the left ventriculo-arterial system and aging in man].

In a haemodynamic and angiographic study at rest conducted in 25 men aged from 22 to 68 years who had no more than another risk factor for arterial disease and showed no evidence of cardiac or arterial disease several parameters were measured or calculated. Firstly, a global index of arterial system function (Ea) and its various factors: Ea = ESP/SV [ESP: left ventricular end-systolic pressure; SV: systolic volume]; Ea = (HR x TSR)+Ea' [HR: heart rate/min; TSR: total systemic resistance] where Ea' = (ESP - AoP/SV) [AoP: mean aortic pressure]. Secondly, the parameters concerning the left ventricle were the mass (m) and the m/EDV ratio [EDV: end-diastolic volume] and indices of the left ventricular systolic and diastolic functions, such as ELV = ESP/ESV [ESV: end-systolic volume], kp: the volumic distensibility module of the left ventricular chamber; relations EF - o ES [EF: ejection fraction; o ES: end-systolic constraint], and kp - m/EDV as indice of left ventricular muscle distensibility. In parallel with the subjects' age, Ea increased by joint augmentation of TSR and Ea' while m, m/EDV, ELV and kp also significantly increased. The inotropic quality of the left ventricular muscle and its intrinsic distensibility were found to be decreased in a few subjects aged over 45. Ea/ELV (reverse of ejection fraction -1) tended to increase (ELV relatively less than Ea), but this increase was not significant (P = 0.10). These results show that in the ageing man the improvement observed in the ejection fraction of the left ventricular pump corresponds roughly to the degradation of the arterial system transfer function, and the arterial system-left ventricle coupling, evaluated by the Ea/ELV ratio, is maintained (better in fact than in arterial hypertension and heart failure). This improvement is achieved by increases of m and, chiefly, m/EDV which compensate for both the increase of Ea and the relative decline of left ventricular muscle contractile quality. There is a disorder of the left ventricular pump diastolic function which is due to geometric changes in the chamber and to changes in the intrinsic distensibility of the left ventricular muscle.

Adult↗
PubMed1992

[Cervico-mediastinal cystic lymphangioma].

Anterior cervico-mediastinal tumors in children, especially if they are cystic, often correspond to the diagnosis of cystic hemolymphangioma. CT and Chest US are contributive for the diagnosis and the pre-operative staging.

Adolescent↗
PubMed1992

[How to evaluate the hemodynamic risk after myocardial infarction?].

The hemodynamic prognosis of myocardial infarction is determined, at medium and long term, by the function of the left ventricle. This is related to the infarct size, the dilatation and geometry of the ventricle secondary to left ventricular remodeling which often follows infarction. In addition to clinical criteria, the hemodynamic parameters which are essential for patient evaluation are the ejection fraction (by radionuclide or conventional ventriculography), rapidly progressive ventricular dilatation (by repeated echocardiography) and circulatory reserve from the exercise stress test data.

Angiocardiography↗
PubMed1992

[Spontaneous hematoma of the thyroid gland: apropos of 2 cases].

Authors report two cases of spontaneous hematoma of the thyroid gland. Emergency surgery was performed on note of them. After reminding the role of different investigations, they discuss the interest of computed tomography to exclude extracranial carotid artery aneurysm. They explain a therapeutic approach according to the repercussions of hematoma: a compressive syndrome requires a difficult emergency surgery.

Aged↗
PubMed1992

[Apropos of acute changes in left ventricular filling induced by antihypertensive treatment].

The purpose of the study was to interpret the acute improvement in left ventricular (LV) filling induced by a new calcium channel blocker (SR 33 557) using Doppler echocardiography. Thirteen patients, 29 to 68 years old (mean 52) with mild to moderate hypertension were examined by Doppler echocardiography before and 4 hours after treatment (SR 33 557: 300 mg). The LV filling parameters, E, A, A/E, VTIM, VTIA, VTIA/VTIM, pressure half time (PHT) and isovolumic relaxation time (IRT) were measured. An index of left atrial pressure was obtained by measuring the mean pulmonary arterial pressure (PAP). The following hemodynamic parameters were also obtained: systolic blood pressure (SBP), heart rate (HR), PR interval (PR), stroke volume (SV) at aortic origin, total systemic resistances (TSR), pulse wave velocity (PWV) at thoracic descending aorta, LV end systolic stress (ESS), LV geometry (thickness/radius: th/r) and systolic function indices: mean VCF and contractility (mean VCF-ESS relationship). Following acute treatment, E and VTIM increased, A, VTIA and PHT did not change, and A/E, VTIA/VTIM ans IRT decreased, both significantly (p < 0.05). PAP did not change, HR, SBP, TSR, PWV, ESS decreased and PR increased both significantly (p < 0.05). LV geometry and systolic function did not change. No significant relationship was found between LV filling changes and changes in hemodynamic parameters. In conclusion, the acute increase in early LV filling induced by the calcium blocker treatment may be interpreted as the consequence of the improvement in LV relaxation in the absence of any change in left atrial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Do antihypertensive agents change the incidence of cardiovascular complications of hypertension?].

The main aim of the treatment of hypertension is to reduce the incidence and severity of its complications. Despite some bias affecting the major clinical trials of diuretics and/or beta blockers, the results of the meta-analysis taking them into account demonstrate the effectiveness of the prevention of cerebrovascular complications and the less effective prevention of coronary complications. Progress can be hoped for as a result of new therapeutic categories (converting enzyme inhibitors, calcium channel inhibitors ...) and to a greater extent from new treatment strategies, involving better identification of "genuinely high risk" subjects.

Adrenergic beta-Antagonists↗
PubMed1991

[Left ventricular remodeling and ischemic heart diseases. Therapeutic possibilities].

Left ventricular modeling after myocardial infarction may be modified in three ways: firstly, by limiting the infarct size; secondly, by administering ACE inhibitors: these drugs limit infarct expansion and ventricular dilatation. They reduce the prevalence of secondary left ventricular failure and, in the animal, improve the prognosis. Glyceryl trinitrate also appears to be effective. The third therapeutic option is maintaining the patency of the artery responsible for the infarction, which has a beneficial effect on ventricular remodeling. The respective therapeutic indications of these three options are still a matter of discussion.

Adrenergic beta-Antagonists↗