Biomedical subjects
Publications and source records attributed to Andres Jaussi.
Echocardiography is a key tool in the diagnosis of infective endocarditis. Although transthoracic echocardiography is the first step in the work-up, transoesophageal echocardiography is mandatory for the evaluation of the exact extent of the infectious process. Indeed, perivalvular abscess can fistulate towards different heart chambers, leading sometimes to critical clinical situations.
A now 36-year-old woman developed a suprahepatic inferior vena cava stenosis, 9 years after liver transplantation for extensive liver echinococcosis. The lesion was treated by percutaneous angioplasty and stenting. Five years later, recurrence of echinococosis with intrastent stenosis together with clinical symptoms, prompted surgical treatment. Hepato-atrial anastomosis was performed under cardiopulmonary bypass with good result.
A 25-year-old male asylum-seeker presented with chest pain, exertional dyspnea, and orthopnea 20 years after the surgical repair of a pentalogy of Fallot. An extracardiac mass compressing the right ventricle was subsequently detected and surgical decompression was performed to relieve the resulting right intraventricular hypertension. At operation, the mass proved to be a coagulase-negative, staphylococcal abscess. In addition, the removal of the mass unmasked a previously nonrecognized pulmonary outflow stenosis that required balloon dilatation and beta-blocker therapy. While infections are known to occur after sternotomy, the formation of an abscess in the anterior mediastinum several years after the intervention appears to be exceptional; this diagnosis came to mind only after the more common complications had been considered, e.g., pseudoaneurysm or pericardial hematoma. To our knowledge, this is the first report of an abscess in the anterior mediastinum that had probably formed over many years following a sternotomy, compressed the right ventricle and masked a pulmonary stenosis.
BACKGROUND: With the advent of second harmonic imaging in echocardiography, microbubbles have been observed during opening and closure of mechanical prosthetic valves. The single phenomenon of cavitation, an extremely short event described in the literature, cannot explain the persistence of microbubbles during several hundred milliseconds. Therefore, in vitro we reproduced two distinct phenomena created by a local depression occurring during the closure and/or opening of prosthetic valves: Cavitation and degassing. METHODS: We used a water circuit system enriched with CO(2) that passes through a Venturi tube in order to create variable pressure gradients. Three types of observations were performed: (1). the dimensions of the bubbles as a function of pressure, (2). calibration of the echocardiograph, and (3). comparison and illustrations of the difference between bubble formation by cavitation (vaporization) and degassing (liberation of CO(2)). RESULTS: According to the different pressures exerted, the dimensions of the bubbles only vary by several microns, not measurable in practice. Second, the calibration of the echocardiograph reveals that the dimensions of the bubbles measured by ultrasound are greater by a factor of 1.75. Finally, the observed cavitation is a short phenomenon (several milliseconds) and happens under a great local pressure gradient. The degassing produces microbubbles lasting up to as long as > 1 second under much lower pressure. CONCLUSION: This in vitro study suggests that microbubbles observed during several hundred milliseconds after the opening of prosthetic cardiac valves are the result of degassing of CO(2) in blood rather than a cavitation phenomenon as suggested in the literature.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
OBJECTIVES: The present study was designed to determine if patients with an echocardiographic diagnosis of idiopathic dilated cardiomyopathy should be submitted to coronary arteriography. BACKGROUND: Whether echocardiography allows distinction of idiopathic dilated cardiomyopathy from severe coronary heart disease remains controversial. METHODS: A questionnaire was sent out to the members of the Swiss Society of Cardiology. In the first study 78 patients with an echocardiographic diagnosis of idiopathic dilated cardiomyopathy who had undergone coronary arteriography or had been followed-up for >5 years were investigated. In a second study, the echocardiograms of 50 patients with either idiopathic cardiomyopathy or severe coronary heart disease, all of whom had also undergone coronary arteriography, were reviewed by two independent echocardiographers without access to any complementary information. RESULT: The questionnaire revealed that one half of the Swiss cardiologists generally refer such patients for coronary arteriography. The first study showed that the diagnosis of idiopathic dilated cardiomyopathy was confirmed in all cases, in which the echocardiographer had been certain of the diagnosis (64/78 [82%]). In the uncertain cases (14 [18%]) coronary arteriography revealed 9 idiopathic cardiomyopathies, 3 coronary heart diseases, and 2 mixed etiologies. The second study showed that a correct diagnosis was achieved in 85% of cases. Furthermore, the echocardiographers were able to specify those patients with an uncertain diagnosis who would therefore require coronary arteriography. CONCLUSIONS: In the overwhelming majority of cases, echocardiography can distinguish idiopathic dilated cardiomyopathy from severe coronary heart disease. Coronary arteriography is only indicated when the echocardiographer is uncertain of the diagnosis. The routine and costly practice of coronary arteriography of these patients does not appear to be justified.
BACKGROUND: Exercise echocardiography (EE) is being used increasingly as an investigative technique now that dynamic images can be captured digitally. Its equivalent reliability with scintigraphic methods has been demonstrated in a hospital setting. This study analyzes its impact on daily practice. MATERIALS AND METHODS: Standardized progressive stress was produced by supine bicycle ergometry. Echocardiographic images of complete cardiac cycles were obtained in standard apical and parasternal short-axis views before, during, and after maximum effort, and digitized for simultaneous analysis of synchronized images at rest and during exercise. Two hundred sixteen patients (175 men and 41 women; mean age 58 +/- 10 years) were studied. RESULTS: Image quality was suboptimal in 4 cases. In the remaining 212 cases, ischemia was detected in 91 cases, and the test was negative in 114 cases and doubtful in 7 cases. Control by selective coronary angiography, as indicated by the clinical situation, was performed in 52 cases. In this particular group, EE showed 87% sensitivity, which is significantly higher than the 59% recorded for conventional exercise testing (P < 0.0001). CONCLUSIONS: EE by bicycle ergometer in the supine position is a valid, noninvasive investigative technique that can be used in an outpatient situation (feasibility 95%) since it is readily available. Its value appears to be greatest in cases in which exercise ECG is not conclusive. A negative result enables the initial cardiologist to reassure the patient immediately, which has been demonstrated in the literature to have favorable prognostic value. (ECHOCARDIOGRAPHY, Volume 13, May 1996)