A Amery

Outcome of Recent Thromboembolic Occlusions of Limb Arteries Treated with Streptokinase

All our patients with a recent thromboembolic occlusion of limb arteries treated with streptokinase have been reviewed retrospectively. Clearing of the main artery, as judged by arteriography or reappearance of arterial pulsations, occurred more often when treatment was started early. If only patients with an iliac, femoral, or popliteal artery occlusion are considered, those who received a lower initial dose had a significantly higher clearing rate and a significantly lower mortality than those who received a high initial dose (500,000 units of streptokinase or more). Therefore an initial standard dose of 1,200,000 units of streptokinase is no longer recommended in these conditions, and even an individually titrated initial dose of more than half a million units could be hazardous. If no neurological abnormalities were present on admission amputation was never necessary, even if clearing of the main artery did not occur. If there was sensory loss of at least part of a limb, amputation was avoided only if the pulsations returned in at least one artery of hand or foot.

Short report: Ambulatory blood pressure in normotensive compared with hypertensive subjects

Objective: To delineate more precisely an operational threshold for making clinical decisions based on ambulatory blood pressure (ABP) measurement by studying the ABP in subjects who were diagnosed as either normotensive or hypertensive by conventional blood pressure (CBP) measurement. Subjects: Twenty-four research groups recruited 7069 subjects. Of these, 4577 were normotensive (CBP ≥140/90mmHg), 719 were borderline hypertensive (systolic CBP 141–159mmHg or diastolic CBP 91–94mmHg) and 1773 were definitely hypertensive. Of the subjects in the last of these categories, 1324 had systolic hypertension (systolic CBP ≤160 mmHg) and 1310 had diastolic hypertension (diastolic CBP ≤95 mmHg). Hypertension had been diagnosed from the mean of two to nine (median two) CBP measurements obtained at one to three (median two) visits. Results: The 95th centiles of the 24-h ABP distributions in the normotensive subjects were (systolic and diastolic, respectively) 133 and 82 mmHg. Of the subjects with systolic hypertension, 24% had 24-h systolic ABP <133 mmHg. Similarly, 30% of those with diastolic hypertension had 24-h diastolic ABP <82 mmHg. The probability that hypertensive subjects had 24-h ABP below these thresholds tended to increase with age and was two- to fourfold greater if the CBP of the subject had been measured at only one visit and if fewer than three CBP measurements had been averaged for establishing the diagnosis of hypertension. By contrast, for each 10-mmHg increment in systolic CBP, this probability decreased by 54% for 24-h systolic ABP and by 26% for 24-h diastolic ABP, and for each 5-mmHg increment in diastolic CBP it decreased by 6 and 9%, respectively. Conclusions: The ABP distributions of the normotensive subjects included in the present international database were not materially different from those in previous reports in the literature. One-fifth to more than one-third of hypertensive subjects had an ABP which was below the 95th centile of the ABP of normotensive subjects, but this proportion decreased if the hypertensive subjects had shown a higher CBP upon repeated measurement. The prognostic implications of elevated CBP in the presence of normal ABP remain to be determined.

Thrombolytic Therapy with Streptokinase Using a Standard Dosage Scheme

The term thrombolytic therapy refers to the attempted removal of preformed intravascular fibrin occlusions using fibrinolytic agents. Several substances have been described as inducing a fibrinolytic state in the peripheral blood ; however, for only a few of these (namely, the plasminogen activators streptokinase and urokinase) was it proved beyond reasonable doubt that administration resulted in an increase in fibrinolytic activity to the point of dissolving intravascular thrombi. After critical clinical evaluation the overall results with streptokinase-plasmin mixtures were rather disappointing and it was still unclear which of the two agents was responsible for the action. The purpose of this paper is to demonstrate that where a standard dosage scheme which has been proved to induce thrombolysis can be used for streptokinase administration, cumbersome laboratory controls become non-essential, thus making clinical trials accessible to a larger group of investigators.

Percutaneous transluminal renal angioplasty: initial results and long-term follow-up in 202 patients.

Percutaneous transluminal renal angioplasty was performed in 202 patients with 250 stenoses. The procedure was successful in 201 of 250 (83%). Results were better for postostial atherosclerotic lesions (94%), fibromuscular lesions (83%), and transplant kidneys (71%) than for ostial atherosclerotic lesions (29%). Of all the patients, 61% had reduced blood pressures following the procedure, with cure (diastolic blood pressure ≤90 mm Hg) in 31% of the patients. Cure rate with a mean follow-up of 25.8±19.4 months was 21% in bilateral atheromatous lesions, 30% in unilateral atheromatosis, 65% in unilateral fibromuscular disease, and 40% in bilateral fibromuscular dysplasia. Of the transplanted patients, 60% were cured. Complications occurred in 23 (11%) of the patients. Recurrence of stenoses occurred in 16 lesions (8%). 80% within the first year after the procedure.

Calcium, vitamin D-endocrine system, and parathyroid hormone in black and white males.

SummaryThe serum and urinary calcium, 25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), and parathyroid hormone (PTH) were studied in healthy black and white males living in Belgium, and the results were compared to data in blacks of similar age living in Zaïre. Dietary calcium and vitamin D were estimated in a subsample of blacks and whites examined in Belgium. Compared to whites (9.51±0.28 mg%) serum calcium was somewhat lower in blacks (9.26±0.27 mg% in Belgium; 9.19±0.48 mg% in Zaïre). The 24 hour urinary calcium excretion averaged 215.0±16.7 mg% in whites and was higher (P<0.05 or less) than in blacks (115±71 mg% in Belgium; 36±33 mg% in Zaïre). The serum 25OHD levels were similar in whites and blacks evaluated in Zaïre, both being higher (P<0.05 or less) than in blacks living in Belgium. In the latter blacks, an inverse correlation was observed between the 25OHD level and the duration of the stay in a temperate climate. Parathyroid hormone levels were slightly higher in blacks living in Belgium than in the other two groups of subjects. The serum levels of 1,25(OH)2D3 and human vitamin D-binding protein were similar in the three groups of subjects. Dietary calcium averaged 541±152 mg/day in blacks and was significantly (P<0.001) less than in whites (1,203±508 mg/day), whereas no significant difference was observed in dietary vitamin D intake between blacks and whites. It is concluded that calcium intake is low in blacks but stimulation of parathyroid hormone and 1,25(OH)2D3 required to achieve normocalcemia does not occur.

Mechanism of hypotensive effect during beta-adrenergic blockade in hypertensive patients

The mechanism of the hypotensive effect during beta-adrenergic blockade in hypertension was studied in 38 patients with renal or essential hypertension using the new cardioselective beta blocker, Tenormin. During 5 weeks hospitalization the patients received first a placebo for 5 to 12 days, then a 75 mg. dose of Tenormin was given daily for 1 week, and thereafter the dose was doubled weekly as necessary up to 600 mg. daily. The blood pressure decreased from 180 +/- 26.2/118. /- 13.6 mm. Hg on placebo to 151 +/-25.5/96 +/-13.8 mm. Hg during the final hospitalization period on Tenormin (600 mg. daily). Six patients developed fluid retention and as this occurred blood pressure control was lost. A subsequent follow-up on an outpatient basis of 15 of the patients showed that when the active drug was replaced by a placebo blood pressure rose again, confirming that the initial fall in blood pressure was a genuine effect. Multistage bicycle ergometer exercise tests were performed at weekly intervals to test the degree of beta blockade and indicated that this was nearly complete when a dose of 600 mg. per day was used. A significant correlation between the hypotensive effect and the degree of beta blockade, assessed by exercise tachycardia, was observed. A slight but statistically significant decrease (26 per cent) was observed in the plasma renin concentration, measured recumbent in the morning. This decrease was, however, not correlated with the hypotensive effect of the drug. Although the cardiac output decreased significantly (from 5.5 +/-1.7 to 4.3 +/- 1.1 L per minute, p less than 0.001), no correlation was found in individual patients between the cardiac output and the blood pressure decrease. On the other hand, for the total group of catheterized patients (n = 28) the calculated total peripheral resistance did not change significantly. Yet a significant correlation was found between the changes in total resistance and the hypotensive effect. This suggests that the reaction of the peripheral vessels rather than the cardiac output decrease determines whether the drug will produce a major decrease of blood pressure in patients with hypertension.

Familial aggregation of blood pressure, anthropometric characteristics and urinary excretion of sodium and potassium—A population study in two Belgian towns

Blood pressure and anthropometric characteristics were measured on two separate occasions and the urinary sodium and potassium excretion determined from one 24-hr urine collection in a random population sample (n = 612) of two Belgian towns. After adjusting for confounding factors familial aggregation of these measurements was studied by computing correlation coefficients for the various intrafamilial relationships. Spouses are genetically dissimilar and share a common home environment only from adulthood on. The spouse-spouse correlations for blood pressure, body weight, body mass index and urinary sodium were therefore not significant, whereas the close spouse-spouse correlation for height (r = 0.29) may be explained by assortive marriage. Sibs not only share a common home environment, but also part of their genetic material. Significant sib-sib correlations could therefore be demonstrated for diastolic blood pressure (r = 0.21), height (r = 0.32), body mass index (r = 0.24) and urinary sodium (r = 0.34). For systolic pressure the father-son (r = 0.33) and mother-daughter (r = 0.24) correlations were significant, whereas the other parent-offspring correlations for systolic and diastolic pressure were not statistically different from zero. The tendency of the correlation coefficients for body weight and body mass index to be higher in mother-offspring than in father-offspring pairs suggests a closer maternal role in the determination of calorie intake in offspring. The parent-offspring correlations for urinary sodium were only significant in father-daughter (r = 0.24) and mother-son (r = 0.21) pairs. The fact that potassium, in contrast to sodium, is rarely used as an artificial additive in food preparation may explain why the correlations for urinary potassium were relatively high in all relationship pairs, varying from 0.20 to 0.34.

Hypotensive action and side effects of clonidine-chlorthalidone and methyldopa-chlorthalidone in treatment of hypertension.

In an open, randomized, cross-over study the hypotensive action and side effects of clonidine-chlorthalidone and methyldopa-chlorthalidone combinations were compared. The diastolic morning blood pressure could be reduced to 95 mm. Hg or below in significantly more patients with clonidine than with methyldopa. Side effects, however, were more commonly encountered during the clonidine than during the methyldopa phase.

Acute haemodynamic and humoral responses to felodipine and metoprolol in mild hypertension

SummaryOral administration of felodipine to 10 patients with mild essential hypertension acutely reduced systemic vascular resistance (SVR) by 40% after 30 min. The change in SVR was significantly related to age (r=−0.74). The reduction in the intraarterially measured brachial artery pressure was limited to 15/13 mmHg, due to a rise in cardiac output (CO). The tachycardia was sustained for 90 min, as was an elevation of plasma noradrenaline. There was a transient increase in stroke volume, associated with a reduction in pulmonary capillary wedge pressure, which was at least partly due to a reduced intravascular volume. In contrast to SVR, pulmonary vascular resistance was not affected by felodipine. Addition of intravascular metoprolol after 90 min decreased HR and CO and augmented SVR. The felodipine-induced rise in plasma renin activity (PRA) of 100% was completely reversed by metoprolol. Plasma angiotensin II (PA II) rose by 15% during felodipine, whereas plasma aldosterone concentration (PAC) was not affected. Thus, actuely administered felodipine was a potent dilator of systemic but not of pulmonary arterioles, it stimulated the sympathetic nervous system, and reduced left ventricular filling pressure. The rise in plasma renin did not result in a higher plasma aldosterone level, due partly to reduced generation of angiotensin II.

Intracellular sodium and the response to nitrendipine or atenolol in African blacks.

The relationship between the hypotensive effect of nitrendipine (N), 20 mg/day (n = 17), or atenolol (A), 100 mg/day (n = 17), and the erythrocyte sodium [( Na]i) and potassium [( K]i) concentrations was investigated in hypertensive African blacks during a randomized double-blind study. After 6 weeks, both treatments significantly reduced supine and standing blood pressures; however, the magnitude of the decrease in supine systolic (-22.0 +/- 2.0 vs -12.1 +/- 3.4 mm Hg) and diastolic (-14.1 +/- 1.3 vs -7.6 +/- 2.1 mm Hg) pressures and in standing diastolic pressure (-16.0 +/- 1.7 vs -9.2 +/- 2.0 mm Hg) was more pronounced (p less than 0.05) in the N-treated than in the A-treated group. Pulse rate, plasma aldosterone, and plasma renin activity were lower (p less than 0.05) in the A-treated patients. Neither treatment had significant influence on [Na]i, [K]i, or ouabain-sensitive sodium efflux. The N-induced changes in supine systolic and diastolic pressure correlated (p less than 0.05) with age (r = -0.65 and r = -0.58, respectively) and pretreatment plasma renin activity (r = 0.71). Multiple regression analysis demonstrated a negative association between pretrial [Na]i and the change in systolic pressure during N treatment that was independent of age, pretreatment blood pressure, and change in pulse rate. Age and the change in supine pulse rate were also independently correlated with the change in diastolic pressure during N treatment. The results show a greater antihypertensive efficacy of N than A in the patients entered in this study and suggest that a higher intracellular sodium concentration could predict a better hypotensive response to N.