[Percutaneous artificial heart valves: from animal experimentation to the first human implantation in a case of calcified aortic stenosis]. / Valves cardiaques artificielles percutanées: de l'expérimentation animale à la première implantation humaine dans un cas de rétrécissement aortique calcifié.

The development of artificial cardiac valves capable of being positioned by catheter has become an important subject for research, with the objective of treating valvular patients who are not operable or at very high surgical risk. We tested an artificial valve implantable by the percutaneous route, consisting of three leaflets of bovine pericardium sutured to the inside of a stainless steel stent, deployable by inflating a balloon. Following laboratory evaluation, this valve was implanted with success in animals, then for the first time in man, in a case of calcified aortic stenosis. The patient, a 57 year old male in cardiogenic shock, had associated multiple non-cardiac pathology and could not be operated on. Implantation was carried out by the trans-septal anterograde route, the only route available due to severe end stage arteritis. The artificial valve was deposited in the centre of the native aortic valve, without obstructing the coronaries nor reaching the mitral valve. The result was spectacular with instantaneous haemodynamic improvement and excellent valvular function confirmed by transoesophageal echocardiography every 15 days after implantation. Non-cardiac complications marred the progress, dominated by aggravation of pre-existing leg ischaemia, necessitating amputation for which the consequences were fatal at 4 months. This case demonstrates that implantation of a cardiac valve by the percutaneous route is possible in calcified aortic stenosis, and that it brings rapid clinical improvement. This technique could in future constitute an important alternative therapeutic approach for selected patients.

Tissue Doppler imaging differentiates transmural from nontransmural acute myocardial infarction after reperfusion therapy.

BACKGROUND: The evaluation of transmural extent of necrosis after acute myocardial infarction remains a major problem in clinical practice. We sought to determine whether color M-mode tissue Doppler imaging (TDI) could differentiate transmural from nontransmural myocardial infarction. METHODS AND RESULTS: Twenty-one anesthetized open-chest dogs underwent 90 or 120 minutes of left anterior descending coronary artery occlusion followed by 180 minutes of reperfusion. The transmural extension of infarct was measured by triphenyltetrazolium chloride (TTC) staining. Segment shortening in the endocardium and epicardium of the anterior and posterior walls was assessed by sonomicrometry. Regional myocardial blood flow was measured by radioactive microspheres. TDI was obtained from an epicardial short-axis view. We calculated systolic and diastolic velocities within the endocardium and epicardium of myocardial walls and the subsequent myocardial velocity gradient (MVG). TTC staining could identify 2 groups according to the transmural extent of necrosis: 15 dogs had a nontransmural (NT) necrosis (42+/-3% of wall thickness), and 6 dogs developed a transmural (T) infarct (81+/-4% of wall thickness). In both groups, ischemia resulted in a significant and similar reduction in endocardial and epicardial velocities, with a resulting low systolic MVG in the anterior wall (0.10+/-0.07 in NT and 0.10+/-0.08 s(-1) in T). At 60 minutes of reperfusion, systolic MVG failed to change significantly in the transmural group (-0.20+/-0.09 s(-1)). In contrast, it increased significantly after reflow in the NT group compared with ischemic values (-0.99+/-0.20 versus 0.10+/-0.07 s(-1), P:<0.05). CONCLUSIONS: TDI can differentiate transmural from nontransmural myocardial infarction early after reperfusion.

Assessment of nonuniformity of transmural myocardial velocities by color-coded tissue Doppler imaging: characterization of normal, ischemic, and stunned myocardium.

BACKGROUND: Transmural myocardial contractile performance is nonuniform across the different layers of the left ventricular wall. We evaluated the accuracy of color M-mode tissue Doppler imaging (TDI) to assess the transmural distribution of myocardial velocities and to quantify the severity of dysfunction induced by acute ischemia and reperfusion in the inner and outer myocardial layers. METHODS AND RESULTS: Thirteen open-chest dogs underwent 15 minutes of left anterior descending coronary artery occlusion followed by 120 minutes of reperfusion. M-mode TDI was obtained from an epicardial short-axis view. Systolic velocities were calculated within endocardium and epicardium of the anterior and posterior walls. Regional myocardial blood flow was assessed by radioactive microspheres. Segment shortening was measured by sonomicrometry in endocardium and epicardium of both the anterior and posterior walls. At baseline, endocardial velocities were higher than epicardial velocities, resulting in an inner/outer myocardial velocity gradient. Ischemia caused a significant and comparable reduction in endocardial and epicardial systolic velocities in the anterior wall with the disappearance of the velocity gradient. Systolic velocities significantly correlated with segment shortening in both endocardium and epicardium during ischemia and reperfusion. In the first minutes after reflow, endocardial velocities showed a greater improvement than epicardial velocities, and the velocity gradient resumed although to a limited extent, indicative of stunning. CONCLUSIONS: TDI is an accurate method to assess the nonuniformity of transmural velocities and may be a promising new tool for quantifying ischemia-induced regional myocardial dysfunction.

[Analysis and quantification of longitudinal contraction of the left ventricle in myocardial infarction. Value of Doppler myocardial tissue imaging]. / Analyse et quantification de la contraction longitudinale ventriculaire gauche dans l'infarctus du myocarde. Apport du Doppler tissulaire myocardique.

The authors compared the results of conventional 2D echocardiography and those of Doppler tissue imaging in 30 patients in the intensive care unit for acute pulmonary myocardial infarction and 10 normal control subjects, to assess the longitudinal contraction of the left ventricle. Echocardiography was performed in the apical 2 and 4 chamber views to analyse the septal, lateral, posterior and anterior left ventricular walls. Each wall was divided into 3 segments: basal, median and apical. Each segment was scored: 1-normo or hyperkinetic, 2-hypokinetic, 3-akinetic and 4-dyskinetic. Doppler tissue imaging provided the maximum instantaneous velocities in systole and diastole in each segment. In control subjects, the myocardial velocities decreased significantly from the base to the apex, resulting in a systolic and diastolic pressure gradient with each wall between the base and the apex. In patients with myocardial infarction, the myocardial velocities were decreased compared with the control group. Moreover, the myocardial velocity gradient between the base and apex was significantly reduced in the hypo and akinetic walls, both in systole and diastole. These results show that, in myocardial infarction, the longitudinal left ventricular contraction is abnormal and may be analysed and quantified by new indices of myocardial systolic and diastolic function, provided by Doppler tissue imaging.

[Distinguishing between physiologic hypertrophy in athletes and primary hypertrophic cardiomyopathies. Importance of tissue color Doppler]. / Différenciation entre l'hypertrophie physiologique du sportif et l'hypertrophie des cardiomyopathies hypertrophiques primitives. Intérêt du Doppler couleur tissulaire.

In order to assess the value of Doppler tissue imaging (DTI) in the differentiation of physiological hypertrophy of athletes from primary hypertrophic cardiomyopathy (HCM), the authors compared a group of 20 normal, non-athletic subjects, a group of 43 competitive athletes and a group of 20 patients with mild HCM. In addition to the conventional echocardiographic criteria, the velocity of wall motion at the endocardium and epicardium of the interventricular septum and the posterior wall as well as their gradients, were measured throughout the cardiac cycle. No significant difference was observed between normal subjects and the athletes with respect to velocities and the gradients of velocity. Early diastolic velocities of the posterior wall and interventricular septum were significantly lower than those of normal subjects and athletes. The systolic and early diastolic gradients of velocity of the posterior wall were significantly lower in HCM compared with the normal subjects and athletes. The gradient of velocity between the endocardium and epicardium of the interventricular septum was significantly lower in HCM compared with normal subjects in early diastole and with athletes in systole and early diastole. The best Doppler tissue imaging parameter to differentiate pathological hypertrophy of HCM from physiological hypertrophy of athletes was analysis of the gradient of velocity in early diastole of the posterior wall. A value of 0.7 sec-1 differentiated HCM with a sensitivity of 89%, a specificity of 95% and a diagnostic accuracy of 94%. Doppler tissue imaging is a more sensitive and specific technique than conventional Doppler echocardiography for detecting moderate forms of HCM.

Percutaneous mechanical mitral commissurotomy with a newly designed metallic valvulotome: immediate results of the initial experience in 153 patients.

BACKGROUND: Percutaneous balloon valvotomy has become a common treatment of mitral stenosis, but the cost of the procedure remains a limitation in countries with restricted financial resources, leading to a frequent reuse of the disposable catheters. To overcome this limitation, a reusable metallic valvotomy device has been developed with the goals of both improving the mitral valvotomy results and decreasing the cost of the procedure. METHODS AND RESULTS: The device consists of a detachable metallic cylinder with 2 articulated bars screwed onto the distal end of a disposable catheter whose proximal end is connected to an activating pliers. By the transseptal route, the device is advanced across the valve over a traction guidewire. Squeezing the pliers opens the bars up to a maximum extent of 40 mm. The clinical experience consisted of 153 patients with a broad spectrum of mitral valve deformities. The procedure was successful in 92% of cases and resulted in a significant increase in mitral valve area, from 0.95+/-0.2 to 2. 16+/-0.4 cm2. No increase in mitral regurgitation was noted in 80% of cases. Bilateral splitting of the commissures was observed in 87%. Complications were 2 cases of severe mitral regurgitation (1 requiring surgery), 1 pericardial tamponade, and 1 transient cerebrovascular embolic event. In this series, the maximum number of consecutive patients treated with the same device was 35. CONCLUSIONS: The results obtained with this new device are encouraging and at least comparable to those of current balloon techniques. Multiple uses after sterilization should markedly decrease the procedural cost, a major advantage in countries with limited resources and high incidence of mitral stenosis.