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Biomedical subjects

Brian L Rayner

Publications and source records attributed to Brian L Rayner.

5 recordsLinked to original sources
PubMed2006

Effect of losartan versus candesartan on uric acid, renal function, and fibrinogen in patients with hypertension and hyperuricemia associated with diuretics.

BACKGROUND: Hyperuricemia may counter benefits of blood pressure (BP) reduction, although this is controversial. METHODS: We examined the effects of candesartan and losartan on uric acid, creatinine, and fibrinogen. Patients with hypertension and serum uric acid > or = 0.42 mmol/L (7 mg/dL) associated with diuretics were randomized to receive losartan 50 to 100 mg or candesartan 8 to 16 mg for 24 weeks. At randomization and after 24 weeks, systolic and diastolic BP, serum uric acid, creatinine, and fibrinogen were measured. RESULTS: A total of 59 patients were entered into the study (30 in the losartan and 29 in the candesartan group). Mean systolic and diastolic BP were reduced in the candesartan group, from 156 mm Hg at baseline to 132 mm Hg at 24 weeks, and from 90.9 to 80.8 mm Hg respectively, P < .0001), and in the losartan group from 150.3 to 132 mm Hg and from 89.6 to 77.6 respectively, P < 0001). Overall mean values of fibrinogen levels were again reduced from 4.39 g/L at baseline to 4.01 g/L at 24 weeks (P < .02). Mean values of serum uric acid in the losartan and candesartan groups were similar at baseline (0.44 and 0.46 mmol/L, respectively), but they were lower in the losartan group after 24 weeks (0.39 and 0.48 mmol/L, P = .01). Twelve patients (44%) in the candesartan group had a 10% increase in serum creatinine compared with four patients (14.2%) in the losartan group (P < .02). CONCLUSIONS: Candesartan and losartan lowered BP, but only losartan reduced uric acid. The lowering of fibrinogen in both groups may explain the reduction in stroke with angiotensin receptor blockers. The effect of persistent hyperuricemia on renal function requires further study.

Antihypertensive Agents↗
PubMed2004

The chest radiograph. A useful investigation in the evaluation of hypertensive patients.

BACKGROUND: The assessment of target organ damage is important in the evaluation of a hypertensive patient as it provides information on the severity of the hypertension and the cardiovascular risk assessment. The aim of our study was to determine the usefulness of the chest radiograph in the assessment of target organ damage in hypertensive patients. METHODS: Unselected patients attending an academic hypertension clinic were studied. The cardiothoracic ratio and the aortic knob width were measured and compared to other markers of target organ damage. The aortic width was measured in age- and sex-matched controls. RESULTS: Seventy-two hypertensive and 77 age- and sex-matched normotensives were evaluated. There was a highly significant difference the aortic knob width between the normotensive and hypertensive patients (3.28 cm v 3.69 cm, P <.0001). The aortic knob width was significantly correlated with age in normotensive and hypertensive patients, systolic and diastolic blood pressure (BP), and all markers of target organ damage except the electrocardiogram (ECG) voltage. The cardiothoracic ratio was also significantly correlated with age and other markers of target organ damage, but not clinic BP. Multiple regression analysis revealed that only the cardiothoracic ratio (r = 0.34, P <.02) and the ECG voltage (r = 0.58, P <.00005) were independently correlated with left ventricular mass. CONCLUSIONS: The chest radiograph provides important predictive information of associated target organ damage in hypertensive patients.

Adult↗
PubMed2003

A new mutation, R563Q, of the beta subunit of the epithelial sodium channel associated with low-renin, low-aldosterone hypertension.

OBJECTIVE: To determine the relationship between R563Q, a mutation of the renal epithelial sodium channel, and hypertension. METHODS: Hypertensive patients with low renin and aldosterone, hypokalemia or resistant hypertension were selected for DNA analysis. Genomic DNA encoding the C-terminal domain of the epithelial sodium channel beta subunit from hypertensives and controls was amplified by polymerase chain reaction and screened for the R563Q mutation by digestion with Sfc1 restriction enzyme, or sequenced. RESULTS: A previously undescribed mutation, R563Q, of the beta epithelial sodium channel was found in 10 of 139 black hypertensives, but was not present in any of 103 black normotensives, a significant (P = 0.0058) difference in frequency. The frequency of the mutation in the subgroup of black low-renin, low-aldosterone hypertensives (four of 14) was significantly (P = 0.0001) greater than in normotensives, and was also greater (P = 0.041) than in normal-high renin hypertensives, suggesting that R563Q is an activating mutation of the epithelial sodium channel. R563Q was also found in seven out of 250 mixed ancestry hypertensives, and was significantly (P = 0.017) associated with low-renin, low-aldosterone hypertension in this population group. The mutation was found in one of 100 mixed ancestry normotensives but not in any of 136 white hypertensives. Of the 18 R563Q patients, 11 had severe hypertension, leading to renal failure in two cases, while only two had hypokalaemia. CONCLUSIONS: R563Q, a new variant of the beta epithelial sodium channel, is associated with low-renin, low-aldosterone hypertension, in South African black and mixed-ancestry patients. Only a minority of individuals with the R563Q allelle fully express the Liddle's syndrome phenotype.

Adult↗
PubMedDate not supplied

Screening and diagnosis of primary aldosteronism.

Primary aldosteronism (PA) is the commonest form of secondary hypertension in South Africa with an approximate prevalence of 7.5% in the primary-care setting. Hypokalaemia is a poor screening test with 70% of proven cases having normal serum potassium levels. The aldosterone/rennin ratio is a robust screening test with a high sensitivity and specificity, but in South Africa this should be combined with an absolute aldosterone level because of the high incidence of low-renin hypertension in Blacks. The limitations of the ratio, especially with regard to concomitant drug therapy will be discussed in detail. The fludrocortisone suppression test remains the investigation of choice for confirming the diagnosis, but requires four days of hospitalisation. CT scanning will miss 50% of adenomas and incorrectly lateralise the adenoma in occasional cases, and bilateral adrenal venous sampling is the gold standard for indirectly confirming and adenoma by demonstrating lateralisation of aldosterone secretion, but its use is limited by lack of technical expertise in South Africa. Low-dose spironolactone is the medical therapy of choice for PA.

Aldosterone↗