RESUMEN
It has been argued that the aortic valve area (AVA) in patients with aortic stenosis increases with flow. Others, however, have attributed the apparent increase to flow dependence of the empiric constant in the Gorlin formula. We examined the changes in AVA during changes in transvalvular flow induced by dipyridamole infusion in 34 patients with aortic stenosis. Two-dimensional and Doppler echocardiography was used and AVA was calculated according to the continuity equation, which does not include empiric constants. Flow increased in 29, decreased in four, and was unchanged in one patient. There was a linear correlation between percent change in flow and percent change in AVA: delta AVA% = 1.1 + delta flow%. 0.56 (r = 0.72; p < 0.001) In conclusion, AVA was found to be flow dependent. The magnitude of change in AVA observed by noninvasive recordings agrees with previous invasive studies according to the Gorlin formula.
Asunto(s)
Estenosis de la Válvula Aórtica/diagnóstico por imagen , Válvula Aórtica/diagnóstico por imagen , Ecocardiografía Doppler/instrumentación , Hemodinámica/fisiología , Anciano , Anciano de 80 o más Años , Válvula Aórtica/fisiopatología , Estenosis de la Válvula Aórtica/fisiopatología , Velocidad del Flujo Sanguíneo/fisiología , Femenino , Análisis de Fourier , Humanos , Masculino , Persona de Mediana Edad , TransductoresRESUMEN
Dipyridamole single-photon emission tomography (SPET) is used for the detection of coronary artery disease (CAD) and the method has also been applied in patients with aortic stenosis. This study was undertaken to establish the gender-specific normal limits of thallium-201 distribution in patients with aortic stenosis and to apply these normal limits in a larger group of patients with aortic stenosis to obtain the sensitivity and specificity for coexisting CAD. A low-dose dipyridamole protocol was used (0.56 mg/kg during 4 min). Thallium was injected 2 min later and tomographic imaging was performed. Following image reconstruction a basal, a midventricular and an apical short-axis slice were selected. The highest activity in each 6 degree segment was normalised to the maximal activity of each slice. The normal uptake for patients with aortic stenosis was obtained from ten men and ten women with aortic stenosis and a normal coronary angiography. Eighty-nine patients were prospectively evaluated. An area reduction of at least 75% in a coronary artery was considered to be a significant coronary lesion and was found in 57 (64%) patients. With gender-specific curves (-2.5 SD) sensitivity for detecting CAD was 100% and specificity was 75% in men, while sensitivity was 61% and specificity 64% in women. It is concluded that the gender-specific normal distribution of 201Tl uptake in patients with aortic stenosis, using dipyridamole SPET, yields a high sensitivity and specificity for coronary artery lesions in men but a lower sensitivity and specificity in women with aortic stenosis.
Asunto(s)
Estenosis de la Válvula Aórtica/diagnóstico por imagen , Dipiridamol , Radioisótopos de Talio , Tomografía Computarizada de Emisión de Fotón Único , Vasodilatadores , Anciano , Estenosis de la Válvula Aórtica/complicaciones , Estenosis de la Válvula Aórtica/epidemiología , Estudios de Casos y Controles , Enfermedad Coronaria/complicaciones , Enfermedad Coronaria/diagnóstico por imagen , Enfermedad Coronaria/epidemiología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Valores de Referencia , Sensibilidad y Especificidad , Factores SexualesRESUMEN
BACKGROUND: Limited data exist concerning left ventricular thrombi during and after hospitalization in patients treated according to modern principles. The purpose of the present study was to examine the formation and resolution of left ventricular thrombi during the first month in patients with acute anterior myocardial infarction treated with streptokinase and aspirin. METHODS: Seventy-seven consecutive patients were studied prospectively during the hospital stay and 1-month follow-up study. Aspirin was used routinely, whereas anticoagulants were only used after a decision by the attending physician. Echocardiography was performed within 3 days of admission, before hospital discharge and after 1 month of follow-up. RESULTS: At the first examination, 17 of 77 patients (22%) had a thrombus. At discharge, 73 patients remained in the study. In five (31%) of the 16 patients with early thrombus, the thrombus persisted; in 18 (32%) of the 57 patients without early thrombus, a new thrombus was diagnosed. One month later, 65 patients remained eligible for follow-up study. In three of 20 patients (15%) the thrombus from the second examination persisted and in four of 45 patients (9%) a new thrombus was diagnosed. The disappearance rate between the second and third examination was high irrespective of whether patients were treated with anticoagulants (eight of nine, 89%) or not (nine of 11, 82%). Extensive left ventricular segmental dysfunction and signs of congestive heart failure were associated with the appearance of a left ventricular thrombus. No embolic events were recorded. CONCLUSION: In patients with anterior myocardial infarction treated with streptokinase and aspirin the development and disappearance of left ventricular thrombi is a highly dynamic process. A large proportion of thrombi resolve without additional anticoagulant therapy.
Asunto(s)
Fibrinolíticos/uso terapéutico , Cardiopatías/tratamiento farmacológico , Infarto del Miocardio/tratamiento farmacológico , Inhibidores de Agregación Plaquetaria/uso terapéutico , Terapia Trombolítica , Trombosis/tratamiento farmacológico , Adulto , Anciano , Aspirina/uso terapéutico , Femenino , Ventrículos Cardíacos , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Estreptoquinasa/uso terapéuticoRESUMEN
Dipyridamole is a potent vasodilator used in pharmacologic stress testing. Patients with severe aortic stenosis are not suitable for exercise, and are usually not subjected to testing with vasodilator substances. The aim of the present study was to investigate hemodynamic changes during dipyridamole stress test in patients with aortic stenosis and to see if these changes where reversible by theophylline, an aminophylline derivative. Ten patients with aortic stenosis underwent right and left heart catheterization. Simultaneous recordings of cardiac output, left ventricular and aortic pressures were performed at baseline, after intravenous dipyridamole infusion (0.56 mg/kg dissolved in 250 ml of saline given over four minutes), and after intravenous theophylline injection (115 mg). There was an increase in heart rate, stroke volume and flow, and a decrease in systolic and diastolic blood pressure and in systemic vascular resistance after dipyridamole infusion. Left ventricular stroke work index and pressure time per minute increased after dipyridamole infusion suggesting an increase in myocardial oxygen demand, but there was no significant change compared to baseline after theophylline administration. Less than one third of left ventricular work was due to the resistance of the aortic valve. The aortic valve area changed with changes in flow. It is concluded that cardiac output, left ventricular work and myocardial oxygen demand after dipyridamole infusion increased in patients with aortic stenosis. The systemic vascular resistance seems to be more important determinant of cardiac output than the aortic valve obstruction. The calculated valve area appears to be flow-dependent.(ABSTRACT TRUNCATED AT 250 WORDS)