Effect of postural changes on aldosterone to plasma renin ratio in patients with suspected secondary hypertension

AimsTo study the influence of postural changes on aldosterone to renin ratio (ARR) in patients with suspected secondary hypertension and to evaluate the sensitivity and specificity of the recommended seated ARR compared to supine and upright ARR for primary aldosteronism screening.MethodsFifty-three hypertensive patients were prospectively hospitalized for secondary hypertension exploration (age: 51 ± 12, 66% males). After withdrawal of drugs interfering with renin angiotensin system, plasma aldosterone and direct renin concentration were measured in the morning, at bed after an overnight supine position, then out of bed after 1 hour of upright position and finally 2 hours later after 15 minutes of seating. Minimal renin value was set at 5 μUI/mL.ResultsReferring to ARR cut-off of 23 pg/μUI, the sensitivity of seated ARR was 57.1% and specificity was 92.3%. The negative and positive predictive values were 95.1% and 45.2% respectively. Compared to these results, a cut-off of 19 improved sensitivity to 85.7% with a specificity of 89.7%. Negative and positive predictive values were 98.3% and 41.1% respectively. Seated ARR mean value was lower than supine and upright ARR mean values, due to an overall increase in renin at seating compared to the supine position by factor 1.9 while aldosterone just slightly increased by factor 1.2. Seated ARR correlated to supine and upright ARR: correlation coefficients (r) 0.90 and 0.93 respectively (P < 0.001).ConclusionsCurrent recommended measurement of ARR in the seating position is fairly correlated to supine and upright ARR. A suggested cut-off value of 19 instead of 23 pg/μUI increased the discriminating power of this test.     

在高血压病人中应用醛固酮/肾素活性比值法筛选原发性醛固酮增多症患者

目的应用血浆醛固酮/肾素活性比值法(AAR),从高血压病人中筛选原发性醛固酮增多症(PA)病人。方法应用放免法测定308例高血压病人的血浆醛固酮(A ld)及肾素活性(PRA)。计算AAR,两次AAR≥30者,行高钠试验,同时行双侧肾上腺CT扫描。结果两次AAR≥30者13例,最后确诊为PA者11例,占被调查人数的3.6%。结论AAR≥30是PA患者可靠的筛选指标。     

醛固酮拮抗剂螺内酯在慢性心力衰竭中的应用分析

目的:分析研究醛固酮拮抗剂螺内酯在慢性心力衰竭当中的临床应用价值。方法:选取慢性心力衰竭的患者106例,对照组采取常规治疗,观察组在此基础之上采取醛固酮拮抗剂螺内酯治疗,比较两组疗效。结果:观察组临床总体有效率明显要比对照组高(P0.05);治疗后,观察组的左室舒张末内径及左室射血分数与对照组差异具有统计学意义(P0.05)。结论:慢性心力衰竭采取醛固酮拮抗剂螺内酯进行治疗,疗效显著,值得推广。     

Tubular site of renal sodium retention in ascitic liver cirrhosis evaluated by lithium clearance

Abstract. Renal tubular sodium handling was evaluated in 27 non-azotemic cirrhotic patients with ascites and positive sodium balance and in 17 controls after at least 5 days of a constant sodium intake using the lithium clearance as an index of fluid delivery to the distal tubule. Plasma renin activity and plasma aldos-terone were also evaluated. Sodium fractional excretion, filtered sodium load, absolute sodium distal delivery, lithium fractional excretion and absolute distal sodium reabsorption were significantly lower in cirrhotics than in controls (0.58 ± 0.11 vs. 1.29 ± 0.12%, < 0.001; 12529± 677 vs. 15707±796 μEq min^-1 1.73 m^-2 BSA, <0.005; 2384±135.2 vs. 3685±219.3 μEq min^-1 1.73 m^-2 BSA, < 0.001; 19.5±1.0 vs. 24.2±l.3%, < 0.01; 2299±127 vs. 3485±214 μEq min^-1 1.73 m^-2 BSA, <0.001, respectively). A correlation was found between lithium clearance and sodium clearance only in cirrhotic patients ( r = 0.62; <0.01). Distal sodium reabsorption evaluated as a per cent of filtered sodium load was lower in cirrhotics than in controls (19.1 ±1.0 vs. 22.4±1.2%, <0.05) while distal sodium reabsorption evaluated as a per cent of sodium distal delivery was higher in cirrhotics than in controls (96.7 ± 0.4 vs. 94.4± 0.5%,< 0.005). In both groups a correlation was found between log plasma aldosterone and distal sodium reabsorption evaluated as a per cent of absolute sodium distal delivery ( r = 0.61, <0.01 and r =0.52,<0.05 respectively).
Our study indicates that a decrease in filtered sodium load and an increase in proximal sodium reabsorption play a critical role in the impairment of renal sodium handling in non-azotemic cirrhotic patients with ascites.     

血浆醛固酮与肾素活性比值测定方法标准化问题的探讨

血浆醛同酮与血浆肾素活性比值(ARR)已广泛应用在高血压患者中筛查原发性醛同酮增多症(原醛).研究表明,不同的临床状况(测定方法)会得出不同的ARR.由于没有统一的ARR标准,使得其临床应用难以适从.因此,应该根据所选用的测定方法和本单位的试验条件,采用相应的,同时具最高敏感性、特异件和准确件的ARR.近年来通过控制测定条件,即所谓测定方法标准化,包括:停用降压药2～4周、取同定体位、上午8:00～12:00之间采血、充分钠摄入以及低血钾者补钾等,发现原醛的ARR范围大致在23.6～26.0 ng·dl-1·ng-1·ml-1·h-1之间,说明ARR筛查方法标准化有助于确定和统一筛查原醛的ARR标准.     

Effect of Volume Expansion by Hyperosmolar and Hyperoncotic Solutions under Constant Infusion of Angiotensin II on Plasma Aldosterone in Man and its Counterbalance by Potassium Administration

Abstract. The influence on plasma aldosterone of plasma volume expansion by hyperosmolar and hyperoncotic solutions and its counterbalance by potassium administration was studied in man. All experiments were done during constant infusion of angiotensin II (All) which consequently excluded changes of the endogenous renin. Hyperosmolar infusion of NaCl, mannitol and NaHCO₃ provoked an immediate fall in plasma aldosterone levels and presumably a shift of intracellular potassium to the extracellular compartment. Hyperoncotic solutions of dextran in 0.9% NaCl provoked an immediate fall in plasma aldosterone while dextran in 5% glucose provoked a delayed fall. Administration of minute amounts of potassium could prevent the fall in plasma aldosterone which followed administration of dextran solutions. The same minute amount of potassium, administered without volume expansion, increased plasma aldosterone markedly above the high levels induced by AII. – The data presented add further evidence for the important role of potassium as a mediator in aldosterone regulation. They indicate that intracellular potassium changes at the adrenal level, rather than plasma potassium concentration, probably exert the regulatory function in aldosterone biosynthesis.     

Responsiveness of the renin-aldosterone system during exercise in young patients with essential hypertension

Abstract. The effect of exercise of gradually increased intensity, i.e. 75 W for 20 min followed by 100 W for 20 min, on plasma renin concentration (PRC) and plasma aldosterone concentration (PAC) was studied in young patients with essential hypertension and normotensive control subjects. During exercise without previous sodium loading PRC and PAC increased to the same degree in both hypertensives and normotensives during light exercise; PRC increased further significantly in the normotensives (63 to 72 μIU/ml (medians), P < 001) but not in the hypertensives (46 to 51 μIU/ml) during heavy exercise. PRC and PAC were significantly correlated during both 75 W (p = 0–633, P<005) and 100 W (p = 0–635, P<005) exercise in the normotensives, but not in the hypertensives. During exercise after loading with 500 ml sodium chloride (0–85 mol/1) PRC and PAC increased in both hypertensives (28 to 42 μIU/ml, P< 0.01; 0.11 to 0.53 nmol/1, P < 001) and normotensives (22 to 33 μIU/ml, P<002; 012 to 0–34 nmol/1, P<00), although to a considerably lower degree than without previous loading. PRC and PAC were, however, significantly higher in the hypertensive than in the normotensive group after exercise. It is suggested that the responsiveness of the renin-aldosterone system is abnormal during exercise in young patients with mild essential hypertension, both without and with previous intravenous sodium loading.