Low angiotensinogen levels are related to the severity and liver dysfunction of congestive heart failure: implications for renin measurements
Article Abstract:
During congestive heart failure, the blood pressure decreases. The arteries in the kidneys are sensitive to changes in blood pressure, and when blood pressure drops the kidneys release an enzyme called renin. Renin converts angiotensinogen (a protein released by the liver) to angiotensin. This causes blood vessels to constrict in an attempt to increase the blood pressure and restore it to its normal level. However, during heart failure, there is a reduction in the blood flow to the liver, and the liver stops releasing angiotensinogen. Therefore, in congestive heart failure, a situation develops in which plasma levels of renin released by the kidney go up, and plasma levels of angiotensinogen released by the liver go down. Measurements of plasma levels of renin are used to predict the severity of heart failure. There are two methods for measuring plasma renin levels. The first method, called plasma renin activity (PRA), involves measuring renin activity based on the amount of angiotensinogen that is converted to angiotensin. However, since plasma levels of angiotensinogen are reduced during heart failure, this method will cause the plasma level of renin to be drastically underestimated. The second method involves directly measuring levels of renin in plasma samples using monoclonal antibodies that specifically bind to renin. This procedure is called immunoradiometric assay (IRMA). In 37 patients with mild to severe congestive heart failure, it was observed that as the severity of heart failure increased, the underestimation of plasma renin levels by the PRA method increased. The IRMA method gave an accurate estimate of plasma renin levels, and showed that plasma renin levels are increased during heart failure. Also, it was observed that the decrease in plasma angiotensinogen was related to the severity of heart failure. The plasma levels of other liver proteins (prealbumin and retinol-binding protein) also were reduced and related to the severity of heart failure. It is concluded that low plasma levels of angiotensinogen may be a marker of the severity of congestive heart failure, and that IRMA is the best way to measure plasma renin levels. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1991
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Clinical, radiographic, and hemodynamic correlations in chronic congestive heart failure: conflicting results may lead to inappropriate care
Article Abstract:
Clinical examination and X-rays are often used to assess the severity of and monitor treatment of chronic congestive heart failure, the inability of the heart to pump blood efficiently, which results in congestion of the lungs. The relationships among clinical history, physical examination, chest X-rays, and pulmonary capillary wedge pressure (PCWP, a circulatory measure) were assessed in 52 patients with congestive heart failure. The patients were divided into three groups depending on their PCWP. Group one had a normal PCWP of 15 millimeters of mercury (mm Hg) or less, and consisted of 19 patients. Group two had mildly to moderately elevated PCWP of 16 to 29 mm Hg, and consisted of 15 patients. Group three had a markedly elevated PCWP of 30 mm Hg or more and consisted of 18 subjects. Physical and X-ray signs of congestion were more evident in patients with elevated PCWP, but were not reliable for classifying patients into groups with different filling pressures, or pressures with which the heart is filled with blood. Physical and X-ray findings were poor predictors for identifying patients with PCWP of 30 mm Hg or greater. There was no X-ray evidence of congestion in the lungs in eight patients of Group two and seven patients of Group three. Right atrial pressure was correlated with PCWP, and a right atrial pressure of more than 10 mm Hg was associated with PCWP values greater than 20 mm Hg. These findings show that clinical, X-ray, and circulatory measurements may be inconsistent, and the absence of X-ray or clinical evidence of congestion is not always associated with a normal PCWP. Hence it is unclear whether treatment aimed at improving PCWP is more beneficial than improving clinical and X-ray signs of congestion. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1991
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Elderly patients with congestive heart failure under prepaid care
Article Abstract:
Medicare beneficiaries have been encouraged by the Health Care Financing Administration to enroll in health maintenance organizations (HMOs) instead of receiving fee-for-service (FFS) care. HMOs are associated with fewer hospital admissions than FFS care. However, a decrease in the use of inpatient services may have adverse consequences for elderly patients. In addition, financial risks placed on physicians caring for elderly patients may adversely affect relations between the physician and patients. These issues have resulted in concern over the quality of care provided by Medicare HMOs. The effects of financial risks on the quality of care provided by Medicare HMOs were assessed by the National Medicare Competition Evaluation. This study previously reported the patients' satisfaction with care, delivery of routine and health maintenance care for outpatients, and performance of surgery to treat colorectal cancer. The management by HMOs of elderly patients with congestive heart failure (CHF) was assessed. CHF is a chronic condition, characterized by the inability of the heart to pump blood, leading to congestion of the lungs. The care of 170 patients with CHF who were enrolled in one of eight Medicare HMOs and of 191 FFS patients with CHF, was assessed. The evaluation and management of CHF were similar for both HMO and FFS patients, although salt restriction was more frequently advised for HMO patients. Drug regimens were changed more often with FFS patients than HMO patients. Follow-up visits one week after hospital discharge were arranged more often for HMO patients than for FFS patients. These findings suggest that HMO patients with CHF may receive more effective continuity of care for a chronic illness such as CHF. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Medicine
Subject: Health care industry
ISSN: 0002-9343
Year: 1991
User Contributions:
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