RESUMEN
The accuracy of technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) for the assessment of myocardial viability in patients with coronary artery disease and left ventricular (LV) dysfunction is not defined completely. This study determines whether the performance of Tc-99m sestamibi SPECT for viability detection differs between patients with mild-to-moderate coronary artery disease. Patients with regional and/or global LV dysfunction were separated into 2 groups on the basis of LV ejection fraction (EF) at rest: group 1 (LVEF > 25%, mean 36 +/- 6%, n = 9), and group 2 (LVEF < or = 25%, mean 17 +/- 5%, n = 11). All patients underwent semiquantitative Tc-99m sestamibi SPECT and positron emission tomography (PET) at rest with N-13 ammonia and F-18 fluorodeoxyglucose. The overall regional concordance of SPECT and PET for viability detection was 89% in group 1 and 78% in group 2 (p = 0.002). Discordance in group 2 was almost exclusively due to PET viable and/or SPECT nonviable regions. In regions with hypoperfusion at rest by PET, concordance was 78% in group 1 and only 64% in group 2 (p = 0.0015). In regions with reduced perfusion and relatively increased metabolic activity ("flow: metabolism mismatch"), Tc-99m sestamibi SPECT identified 88% of regions in group 1 as viable, but only 42% of regions in group 2 (p = 0.002). Thus, while Tc-99m sestamibi semiquantitative SPECT at rest shows a good concordance with PET for the detection of myocardial viability in patients with coronary artery disease with mild-to-moderate LV dysfunction, it may underestimate myocardial viability in patients with severe LV dysfunction, particularly in those patients with hypoperfusion at rest as assessed by PET.
Asunto(s)
Angina de Pecho/diagnóstico por imagen , Corazón/fisiopatología , Infarto del Miocardio/diagnóstico por imagen , Tecnecio Tc 99m Sestamibi , Tomografía Computarizada de Emisión de Fotón Único/métodos , Tomografía Computarizada de Emisión/métodos , Función Ventricular Izquierda/fisiología , Adulto , Anciano , Estudios de Evaluación como Asunto , Humanos , Persona de Mediana Edad , RadiofármacosRESUMEN
The diagnosis of pedal osteomyelitis is often complicated by the presence of pre-existing bony abnormalities. In this study, the utility of radiolabeled white blood cell imaging for the detection of complicated pedal osteomyelitis was evaluated. Twenty-seven men and women were prospectively enrolled and underwent plain film radiography, three-phase bone scan, and Tc-99m hexamethylpropylamine oxine white blood cell scintigraphy of their feet. The presence or absence of osteomyelitis was confirmed in all subjects by microbiologic and histopatholigic analysis of resected bone tissue. The results indicated that white blood cell imaging was more sensitive (90%) and specific (86%) for infection than either bone scan (75% sensitive, 29% specific) or plain film radiography (55% sensitive, 57% specific). This preliminary study suggests that Tc-99m hexamethylpropylamine oxine-labeled white blood cell scintigraphy is a simple, accurate test for the detection of pedal osteomyelitis.
Asunto(s)
Enfermedades del Pie/diagnóstico por imagen , Compuestos de Organotecnecio , Osteomielitis/diagnóstico por imagen , Oximas , Anciano , Complicaciones de la Diabetes , Femenino , Enfermedades del Pie/complicaciones , Enfermedades del Pie/diagnóstico , Humanos , Leucocitos , Masculino , Persona de Mediana Edad , Osteomielitis/complicaciones , Osteomielitis/diagnóstico , Estudios Prospectivos , Cintigrafía , Sensibilidad y Especificidad , Exametazima de Tecnecio Tc 99mRESUMEN
A randomized, double blind, parallel study was performed to compare the effects of nifedipine gastrointestinal therapeutic system (GITS) to hydrochlorothiazide (HCTZ) in the management of the elderly hypertensive. Eighteen patients, mean age 65 +/- 5 years, with Stage I-III diastolic hypertension (sitting diastolic BP between 90 and 115 mm HG) were included in each treatment group. Following a 2 to 8 week placebo washout phase, patients received either nifedipine GITS or HCTZ and were titrated over 5 weeks to achieve a goal diastolic blood pressure less than 90 mm Hg. Patients were then continued on medication during an 8 week maintenance phase. Treatment effect on systolic and diastolic blood pressure was assessed. Serum electrolytes, lipids, blood urea nitrogen, and creatinine were measured before and after treatment. Posttreatment changes in renal and cardiovascular function, as well as left ventricular mass were evaluated. The results showed significant reductions in systolic and diastolic blood pressure with both drugs; no treatment difference was found, although goal blood pressure was achieved more rapidly with nifedipine GITS (28 v 34 days, P < .05). BUN was significantly increased only after diuretic therapy (P < .01) and serum potassium fell to a greater degree with HCTZ (0.3 mEq/L v 0.1 mEq/L) than with nifedipine GITS. No statistically significant changes in left ventricular mass, ejection fraction, glomerular filtration rate, or renal blood flow were seen after therapy with either drug. However, the time peak LV diastolic filling rate decreased with nifedipine GITS (197 to 164 msec) and increased with HCTZ (172 to 198 msec). This treatment difference approached statistical significance (P = .07). Adverse side effects of treatment were reported by 50% of nifedipine GITS patients and 28% of patients treated with HCTZ. This treatment difference was not statistically significant. We conclude that both nifedipine GITS and HCTZ monotherapy provide significant blood pressure reduction in older hypertensives with Stage I-III diastolic hypertension. Both drugs are well tolerated with no significant adverse effect on renal or cardiovascular function after short term therapy.
Asunto(s)
Antihipertensivos/uso terapéutico , Bloqueadores de los Canales de Calcio/uso terapéutico , Hidroclorotiazida/uso terapéutico , Hipertensión/tratamiento farmacológico , Nifedipino/uso terapéutico , Anciano , Anciano de 80 o más Años , Antihipertensivos/administración & dosificación , Antihipertensivos/efectos adversos , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Volumen Sanguíneo/efectos de los fármacos , Volumen Sanguíneo/fisiología , Bloqueadores de los Canales de Calcio/administración & dosificación , Bloqueadores de los Canales de Calcio/efectos adversos , Método Doble Ciego , Femenino , Humanos , Hidroclorotiazida/administración & dosificación , Hidroclorotiazida/efectos adversos , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad , Nifedipino/administración & dosificación , Nifedipino/efectos adversos , Estudios Prospectivos , Circulación Renal/efectos de los fármacos , Función Ventricular Izquierda/efectos de los fármacos , Función Ventricular Izquierda/fisiologíaRESUMEN
The central benzodiazepine receptor tracer [N-methyl-11C]iomazenil (Ro 16-0154) was synthesized by alkylation of the desmethyl precursor noriomazenil with [11C]methyl iodide. The [11C]CH3I (prepared by reduction of [11C]CO2 with LiA1H4 followed by reaction with HI) was reacted with noriomazenil in N,N-dimethylformamide and Bu4N+OH- for 1 min at 80 degrees C and purified by HPLC (C18, 34% CH3CN/H2O 7 mL/min). The product was obtained with synthesis time 35 +/- 5 min (mean +/- SD, n = 7), radiochemical yield (EOB) 36 +/- 16%, radiochemical purity 99 +/- 1%, and specific activity 5100 +/- 2800 mCi/mumol. Absorbed radiation doses were calculated from previously acquired human biodistribution data. The urinary bladder wall received the highest dose (0.099 mGy/MBq) for 4.8 h voiding interval and the effective dose equivalent was 0.015 mSv/MBq. After i.v. injection of [11C]iomazenil in an adult baboon or healthy human volunteer, radioactivity accumulated in the cortex with time-activity curves in agreement with results obtained with [11C]flumazenil PET and [123I]iomazenil SPECT studies. The count rate was sufficient to obtain quantitative images up to 2 h post-injection with a 14 mCi injection. These results suggest that [11C]iomazenil will be a useful agent for measuring benzodiazepine receptors in vivo by positron emission tomography.
Asunto(s)
Flumazenil/análogos & derivados , Receptores de GABA-A/metabolismo , Adulto , Animales , Radioisótopos de Carbono , Femenino , Flumazenil/síntesis química , Flumazenil/farmacocinética , Humanos , Radioisótopos de Yodo , Marcaje Isotópico , Ligandos , Masculino , Papio , Espectrofotometría Ultravioleta , Distribución Tisular , Tomografía Computarizada de Emisión , Recuento Corporal TotalRESUMEN
Technetium-99m methoxyisobutyl isonitrile (technetium-99m sestamibi [MIBI]) is distributed in the myocardium according to blood flow. Reports comparing stress rest sestamibi protocols with reinjection thallium or resting fluorodeoxyglucose (FDG), or both, in patients with coronary artery disease have shown appreciable discordance regarding myocardial viability in these settings. We performed this analysis with regard to regional comparisons within discordant segments and made comparisons in a subset of patients who underwent revascularization. Thirty-seven patients with coronary artery disease had single-photon emission computed tomography MIBI, N-13 ammonia/18FDG positron emission tomography (PET), and radionuclide ventriculography performed at rest. One hundred two segments were viable and 29 were nonviable by both MIBI and FDG. The concordance was 71%. In MIBI nonviable/FDG viable segments, most of the discordance was in the inferior wall. In MIBI nonviable discordant segments, FDG accurately predicted an increase in percent regional ejection fraction (preoperative 36% [+/- 5 SE] to postoperative 48% [+/- 5.5 SE][p < 0.0006]). MIBI underestimates myocardial viability as assessed by PET. Seventy-one percent of myocardial segments were concordant by both quantitative sestamibi single-photon emission computed tomography and FDG PET. Discordance in MIBI nonviable segments was predominantly in the inferior wall. PET can be helpful in detecting myocardial viability in patients suspected of having had MIBI nonviability in the inferior wall.
Asunto(s)
Tecnecio Tc 99m Sestamibi , Tomografía Computarizada de Emisión de Fotón Único , Tomografía Computarizada de Emisión , Función Ventricular Izquierda , Adulto , Anciano , Enfermedad Coronaria/diagnóstico por imagen , Enfermedad Coronaria/fisiopatología , Enfermedad Coronaria/cirugía , Desoxiglucosa/análogos & derivados , Radioisótopos de Flúor , Fluorodesoxiglucosa F18 , Humanos , Masculino , Persona de Mediana Edad , Contracción Miocárdica , Ventriculografía con Radionúclidos , Volumen SistólicoRESUMEN
Reverse redistribution (RR) of thallium-201 has been associated with both acute and healed myocardial infarction, and with recent thrombolysis. The physiologic basis for RR in coronary artery disease (CAD) is unclear but may be related to an admixture of viable and scarred myocardium within the RR segment. We performed thallium reinjection imaging at rest to better characterize RR defects in patients with chronic CAD. We found enhanced uptake of 201Tl in 52% of RR segments after reinjection, consistent with significant regional viability that was not evident on redistribution images. We then used a logistic multiple regression analysis to determine whether RR alone or in combination with other scintigraphic findings could predict patient outcome. The results showed that severe RR was an independent predictor of patient outcome. We conclude that RR may have prognostic significance in chronic CAD.
Asunto(s)
Enfermedad Coronaria/diagnóstico por imagen , Corazón/diagnóstico por imagen , Radioisótopos de Talio , Anciano , Enfermedad Coronaria/fisiopatología , Estudios de Seguimiento , Humanos , Pronóstico , Ventriculografía con Radionúclidos , Análisis de Regresión , Función Ventricular IzquierdaRESUMEN
UNLABELLED: The purpose of this study was to assess myocardial metabolic activity in the area of reverse redistribution and determine the prognostic value of reverse redistribution and PET imaging. Reverse redistribution is thought to be a manifestation of reperfusion therapy and associated with a favorable clinical outcome. Preliminary observations from the Thrombolysis and Myocardial Infarction (TIMI) trial suggest that reverse redistribution is associated with higher incidence of future cardiac events. METHODS: Thirty-two patients with chronic coronary artery disease and reverse redistribution on planar thallium scintigraphy had PET 13NH3/18FDG imaging. Radionuclide angiocardiography was performed in 23 patients. RESULTS: Fifty segments showed reverse redistribution on planar thallium images; 19 segments had normal 13NH3 and 18FDG uptake and 17 were ischemic by PET criteria. Thus, a total of 72% (36 of 50) of reverse redistribution segments were PET viable. Sixty-one percent of segments with abnormal regional wall motion and reverse redistribution were PET scar. On follow-up, 31% (10/32) had a cardiac event (nine unstable angina and one myocardial infarction). Fifty percent of patients (5/10) with cardiac events had severe reverse redistribution and PET viability versus 9% (2/22) without cardiac events (p = 0.01). CONCLUSIONS: The majority of thallium reverse redistribution segments was PET viable as judged by 18FDG uptake. Viability in areas of reverse redistribution is not inferred by regional wall motion analysis. Regional PET viability identifies patients with reverse redistribution with a higher likelihood of future cardiovascular events. PET viability assessment may be helpful with the impact of reverse redistribution on planar thallium scintigraphy.
Asunto(s)
Enfermedad Coronaria/diagnóstico por imagen , Corazón/diagnóstico por imagen , Corazón/fisiopatología , Radioisótopos de Talio , Anciano , Amoníaco , Desoxiglucosa/análogos & derivados , Prueba de Esfuerzo , Radioisótopos de Flúor , Fluorodesoxiglucosa F18 , Estudios de Seguimiento , Humanos , Masculino , Contracción Miocárdica , Miocardio/metabolismo , Radioisótopos de Nitrógeno , Tomografía Computarizada de EmisiónRESUMEN
Single-photon emission tomography (SPET) imaging in patients with complex partial epilepsy has shown that the seizure focus is characterized by both decreased interictal blood flow and decreased uptake of the benzodiazepine (BZ) receptor tracer iodine-123 iomazenil. The purpose of this study was to examine the confounding effect of decreased flow on iomazenil uptake. The left middle cerebral artery of four rats was occluded, and the animals were simultaneously injected with 25 microCi of iodine-125 iomazenil and 500 microCi of the blood flow tracer [123I]iofetamine (N-isopropyl-p-iodoamphetamine). All rats, including two sham, were sacrificed 1 h after injection, a time when uptake of both agents is nearly maximal. Control experiments showed that arterial occlusion for 1 h did not affect the total number of BZ binding sites. Using a dual autoradiographic technique, the uptake of both [123I]iofetamine and [125I]iomazenil was measured in more than 200 regions showing variable levels of reduced flow and expressed as a percentage of the contralateral homotypic area. The straight line fit of % [125I]iomazenil (y axis) versus % [123I]iofetamine (x axis) in all 200 regions had a slope of 0.74. Insofar as the rat is an accurate model of human subjects with epilepsy, these studies suggest that decreased flow to the epileptogenic focus will linearly exacerbate the decrease in uptake secondary to neuropathologic loss of BZ receptors. Thus, for localization of seizure focus, a single SPET image of [123I]iomazenil in an epileptic patient may have greater sensitivity than a comparable blood flow image, because the former is enhanced by both decreased flow and a loss of BZ receptors.
Asunto(s)
Anfetaminas/metabolismo , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/metabolismo , Arterias Cerebrales/fisiología , Flumazenil/análogos & derivados , Receptores de GABA-A/fisiología , Flujo Sanguíneo Regional/fisiología , Animales , Autorradiografía , Encéfalo/irrigación sanguínea , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismo , Flumazenil/metabolismo , Radioisótopos de Yodo/metabolismo , Yofetamina , Radiografía , Ratas , Ratas Sprague-Dawley , Tomografía Computarizada de Emisión de Fotón ÚnicoRESUMEN
UNLABELLED: SPECT imaging of the brain with [123I]iomazenil has shown avid uptake of the radioligand in a distribution consistent with benzodiazepine receptor binding. The purposes of this study were to measure the whole-body distribution of activity following i.v. administration of [123I]iomazenil and to evaluate the resulting organ radiation burdens. METHODS: Serial total body scans were obtained in healthy volunteers after thyroid blockade and demonstrated avid brain uptake of radioligand. RESULTS: Abdominal imaging showed significant activity retention within the urinary and gastrointestinal tracts consistent with excretion via these routes. Absorbed dose to the urinary bladder was calculated to be 0.19 mGy/MBq, to the lower large intestine 0.079 mGy/MBq, to the upper large intestine 0.066 mGy/MBq, and to the thyroid 0.063 mGy/MBq. CONCLUSION: Thyroid uptake may in part have represented binding to benzodiazepine receptors, since radioligand binding to tissue homogenates prepared from human thyroid showed the presence of benzodiazepine binding sites.
Asunto(s)
Encéfalo/diagnóstico por imagen , Flumazenil/análogos & derivados , Radioisótopos de Yodo , Tomografía Computarizada de Emisión de Fotón Único , Adulto , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Dosis de Radiación , Distribución TisularRESUMEN
Retrospective analysis of precaptopril and postcaptopril DTPA renograms from 88 hypertensive patients was performed to refine the quantitative criteria used to diagnose renal artery stenosis (RAS). Of the 88 patients, 45 had RAS and 43 had normal renal arteries at angiography. Using time-activity curves from the essential hypertensive group, diagnostic washout criteria for a positive DTPA renogram were developed. These were based on the 20 and 30 min/peak activity ratios in each kidney. When the washout criteria were retrospectively applied to patient data as a whole, sensitivity and specificity for RAS were 67% and 79%, respectively. When previously described uptake criteria, based on the time to peak activity in each kidney and the GFR ratio between the kidneys, were applied to the same data, sensitivity and specificity for RAS were 89% and 84%, respectively. Quantitative analysis of the DTPA renogram using the time to peak and GFR ratio was both sensitive and specific for RAS. Measurement of 20 and 30 min/peak renal activity ratios did not improve the accuracy of the test.
Asunto(s)
Captopril , Hipertensión Renovascular/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador , Renografía por Radioisótopo , Obstrucción de la Arteria Renal/diagnóstico por imagen , Pentetato de Tecnecio Tc 99m , Angiografía de Substracción Digital , Tasa de Filtración Glomerular , Humanos , Hipertensión Renovascular/epidemiología , Análisis de Regresión , Obstrucción de la Arteria Renal/epidemiología , Estudios Retrospectivos , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
We studied the uptake, distribution, metabolism and washout of the dopamine D2 receptor ligand [123I]IBZM in healthy subjects (n = 12) with dynamic brain SPECT. The highest radioactivity level was detected in the striatum. Operationally-defined striatal "specific" uptake peaked at 69 min postinjection of radioligand and showed a gradual decline of 15% per hour thereafter. "Specific" uptake at maximal counts represented 53% of the total striatal radioactivity. Two subjects received haloperidol (20 micrograms/kg i.v.) 80 min postinjection of radioligand. Haloperidol caused a 2.6-fold increase in the rate of washout of specific striatal activity in comparison to that in the 10 control subjects and was consistent with drug-induced displacement of radioligand from the dopamine D2 receptor. Two classes of metabolites were detected in plasma and urine: a polar fraction, not extracted by ethyl acetate, and a nonpolar, extractable fraction consisting of parent compound and two compounds having shorter retention times on reversed-phase HPLC. Greater than half the plasma parent was metabolized within 10-15 min after administration. The volume of distribution, estimated from the peak arterial plasma concentration at 50-75 sec, was 7.7-10.2 l; the free (nonprotein bound) fraction of [123I]IBZM after in vitro incubation with blood or plasma was 4.4% +/- 0.4%. These results suggest that [123I]IBZM exhibits uptake in brain regions with high D2 receptor density and shows a relatively stable washout during which drugs affecting dopaminergic transmission may be administered.
Asunto(s)
Benzamidas , Encéfalo/diagnóstico por imagen , Pirrolidinas , Receptores de Dopamina D2/análisis , Tomografía Computarizada de Emisión de Fotón Único , Adulto , Benzamidas/farmacocinética , Encéfalo/metabolismo , Medios de Contraste , Femenino , Haloperidol/farmacología , Humanos , Masculino , Pirrolidinas/farmacocinéticaRESUMEN
Previous work suggests that iomazenil (formerly known as Ro 16-0154) is a useful ligand for static imaging of the benzodiazepine (BZ) receptor with single photon emission computed tomography (SPECT). The present study evaluated the feasibility of dynamic SPECT imaging of cerebral radioactivity following intravenous [123I]iomazenil injection in healthy human subjects, in preparation for future receptor quantitation studies. Maximal brain uptake was reached approximately 25-30 minutes after i.v. administration of the radioligand and represented approximately 12% of the injected dose. The regional distribution of radioactive densities was consistent with the known distribution of BZ receptors in human brain, with highest uptake localized over the occipital area. Washout of cortical radioactivity was regionally variable but relatively slow, with a half-life of approximately 4 hours after the time of peak radioactivity. In summary, [123I]iomazenil is a promising SPECT radioligand for the BZ receptor, with high brain uptake, relatively slow washout of radioactivity, and appropriate regional distribution.
Asunto(s)
Benzodiazepinas/farmacocinética , Encéfalo/efectos de los fármacos , Flumazenil/farmacocinética , Tomografía Computarizada de Emisión de Fotón Único , Adulto , Benzodiazepinas/administración & dosificación , Benzodiazepinas/metabolismo , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismo , Femenino , Flumazenil/administración & dosificación , Flumazenil/metabolismo , Humanos , Inyecciones Intravenosas , Masculino , Radiografía , Ensayo de Unión Radioligante , Receptores de GABA-ARESUMEN
The associations of age, blood pressure and cardiac structure with rapid left ventricular filling were assessed in 47 subjects (21 normotensives and 26 age-matched untreated hypertensives) by 24-h ambulatory blood pressure monitoring, sector-guided M-mode echocardiography and radionuclide ventriculography. Univariate analyses revealed strong negative correlations of the left ventricular filling rate with age, and 24-h systolic and diastolic blood pressure, and a moderate positive correlation with the left ventricular ejection fraction at rest. Multiple regression analysis was performed with these variables, left atrial size and left ventricular mass index. Left atrial size and the left ventricular mass index were dependent on 24-h blood pressure, indicating that these two cardiac structural variables were less important than left ventricular filling. Age was undoubtedly the most important correlate of left ventricular filling, since 88% of the subjects over 53 years of age had reduced left ventricular filling rates regardless of the blood pressure status. However, under the age of 53 years, only the hypertensives had reduced filling rates. Thus, our study shows that the left ventricular filling rate is more dependent on age and 24-h blood pressure than on the left ventricular mass index. Furthermore, in patients over 53 years of age, it is not possible to separate the effects of hypertension on the diastolic function of the heart from the physiological alterations associated with ageing.
Asunto(s)
Envejecimiento/fisiología , Presión Sanguínea/fisiología , Ritmo Circadiano/fisiología , Corazón/fisiología , Monitores de Presión Sanguínea , Ecocardiografía , Femenino , Humanos , Hipertensión/diagnóstico , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad , Tamaño de los Órganos/fisiología , Función VentricularRESUMEN
The distribution of blood pressure (BP) values over the day and night was assessed in a group of 30 never previously treated patients with mild-to-moderate essential hypertension via 24-hour ambulatory BP monitoring. Elevated BP values during the awake hours (greater than 140/90 mm Hg) and sleeping hours (greater than 120/80 mm Hg) were used to calculate the total percentage of abnormal BP values (load) in each patient. The relationship between BP load and several indexes of hypertensive cardiac target organ involvement was compared to the relationships among office (casual), 24-hour average BP values, and cardiac indexes. Casual systolic and diastolic BP values did not correlate with left ventricular mass index, left atrial index, or peak left ventricular filling rate. Both 24-hour average BP and systolic and diastolic BP loads correlated with all indexes of cardiac target organ involvement. The BP loads were related to left ventricular mass index and left atrial index more strongly than were the mean 24-hour BP values; however, they were equally correlated for peak left ventricular filling rate. If greater than 40% of the ambulatory BP values were elevated, the likelihood of increased mass or decreased filling was greater than 61%, whereas if less than 40% of the BP values were elevated, the incidence of an abnormal cardiac test result decreased to less than 17%. These data show that the percentage of elevated BP values that includes both the awake and asleep periods is predictive of cardiac target organ involvement in patients with mild-to-moderate hypertension. Patients with mild hypertension who have more than 40% abnormal BP values should strongly be considered for antihypertensive therapy.
Asunto(s)
Presión Sanguínea , Hipertensión/fisiopatología , Adulto , Anciano , Determinación de la Presión Sanguínea , Cardiomegalia/diagnóstico , Cardiomegalia/fisiopatología , Ecocardiografía , Femenino , Humanos , Hipertensión/diagnóstico , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico , Miocardio/patología , Ventriculografía con RadionúclidosRESUMEN
To determine the associations of age, blood pressure (BP) and cardiac structure with left ventricular (LV) diastolic performance, 47 subjects (21 normotensives and 26 age-matched, previously untreated hypertensives) were studied by 24-hour ambulatory BP monitoring, radionuclide ventriculography and sector-guided M-mode echocardiography. Normotension was defined as an awake ambulatory BP less than 130/80 mm Hg and hypertension as an awake ambulatory BP greater than 135/85 mm Hg. Univariate analyses revealed strong negative correlations of LV filling rate with age (r = -0.67, p less than 0.001), 24-hour systolic or diastolic BP (r = -0.59 for systolic BP and -0.57 for diastolic BP, p less than 0.001 for both) and a modest positive correlation with LV ejection fraction (r = 0.42, p less than 0.05). After multivariate analysis, significant dependencies of both the left atrial index and LV mass index on ambulatory BP were found, which negated the significance of the relation of these 2 cardiac structural variables with LV filling rate. The final regression equation predicted LV filling rate from age, BP and LV ejection fraction. Age was the most important single correlate of LV filling, as evidenced by the 14 of 16 subjects (88%) over the age of 53 years (8 hypertensives, 6 normotensives) who had reduced LV filling rates compared with only 9 of the remaining 31 subjects (29%, all hypertensives) under the age of 53 years with reduced LV filling rates. These data demonstrate that LV filling rate is more dependent upon age and BP than left atrial or LV size.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Envejecimiento/fisiología , Presión Sanguínea , Hipertensión/fisiopatología , Contracción Miocárdica , Adulto , Anciano , Determinación de la Presión Sanguínea/métodos , Volumen Cardíaco , Ecocardiografía , Femenino , Corazón/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico/métodos , Cintigrafía , Estadística como Asunto , Volumen SistólicoRESUMEN
To determine the presence of cardiac disease in hypertensive patients with disparities between physician and out-of-office blood pressures, we prospectively studied three groups of age-matched patients identified by both casual (office) and ambulatory blood pressures: (1) office blood pressure greater than 140/90 mm Hg and awake ambulatory blood pressure of 130/80 mm Hg or less ("office" hypertensives); (2) office blood pressure less than 135/85 mm Hg and awake ambulatory blood pressure of 130/80 mm Hg or less (normotensives); and (3) office blood pressure greater than 140/90 mm Hg and awake ambulatory blood pressure of 140/90 mm Hg or greater ("daytime" hypertensives). In the patients with office hypertension, both the left atrial index and left ventricular mass index were significantly less than in patients with daytime hypertension and not statistically different from those of the normotensive subjects. Left ventricular filling rate at rest and ejection fraction at peak exercise were significantly greater in the office hypertensive group than in the daytime hypertensive group but were no different from those of the normotensive subjects. These findings demonstrate that patients with blood pressure elevation only in the physician's office have cardiac size and function similar to those of normotensive individuals. Thus, the average daily blood pressure best predicts cardiac end-organ damage.