Terence J. Stallard

Assessment of left-ventricular mass and its response to antihypertensive treatment.

50 patients with mild to moderate essential hypertension underwent M-mode echocardiography and continuous intra-arterial ambulatory monitoring of blood pressure. Indices of left-ventricular (LV) mass were derived from echocardiographic data by standard formulae. 43 of the patients were followed up for 12+/-7 months with repeat M-mode echocardiography, and casual blood-pressure measurements. 25 of these patients received antihypertensive therapy and 18 were untreated. Mean 24 h systolic blood pressure was significantly correlated with echocardiographic LV mass; mean 24 h diastolic blood pressure was also correlated, but the relation was weaker. In the treated group there was a significantly greater fall in blood pressure and LV mass index than in the untreated group, and there was a significant correlation between the fall in systolic blood pressure and the fall in LV mass index in the treated group. Systolic blood pressure appears to be an important factor in the pathogenesis of LV hypertrophy, and in hypertensive patients changes in LV mass assessed by echocardiography correlate with changes in blood pressure.

Factors determining direct arterial pressure and its variability in hypertensive man.

SUMMARY Infra-arterial pressure was recorded continuously in 26 patients with uncomplicated essential hypertension under standardized conditions. Recordings were analyzed beat by beat to obtain mean pressures and variability, expressed as tbe standard deflation of the frequency histogram. The major factors influencing variability were tbe level of pressure and tbe Intensity of physical activity; systolic variability increased with progressive impairment of sino-aortic baroreflexes. Diastollc pressure increased with the level of sympathetic activity as reflected by plasma noreplnephrine levels. After allowance for the decrease of plasma renin activity (PRA) with age, direct relationships were observed between PRA (log values) and the level of pressure and systolic variability; plasma angiotensin II values did not correlate. Systolic variability increased with the systolic response to cold but was unrelated to the response to dynamic or isometric exercise. Variability also tended to increase with obesity and was unrelated to age, sex, or race.

Variation in cuff blood pressure in untreated outpatients with mild hypertension―Implications for initiating antihypertensive treatment

: Thirty-two patients with mildly elevated blood pressure (BP), but without target organ damage, attended a BP measuring clinic where duplicate BP measurements were made on 12 visits. During visits 1-3, BP showed a systematic decrease which varied from patient to patient. During visits 4-12, no further systematic changes in BP were observed. During the latter period, between-visit variation in BP was substantial, the standard deviation of the difference in BP from one visit to another being 10.4 mmHg for systolic, 6.8 mmHg for diastolic (phase IV) and 7.0 mmHg for diastolic (phase V). These values were used to determine the chance that the BP estimated after a number of visits differed from the average stable BP. After visit 4, the chance of a difference of 5 mmHg or more was 0.50 systolic blood pressure (SBP) and 0.32 diastolic blood pressure (DBP; phase V). Increasing the number of visits to six or more reduced the chance of error. Before initiating lifelong treatment in mild hypertensives free of target organ damage, BP should be recorded in duplicate on a minimum of six visits.

Cardiovascular response in black and white hypertensives.

Sixteen untreated black patients with mild- to- hypertension and no evidence of target organ damage were matched for age, sex, casual blood pressure (BP), and socioeconomic status with 16 white hypertensives. All patients were studied under standardized conditions in the hospital where they underwent continuous intraarterial ambulatory monitoring of BP and assessment of BP control mechanisms. BP characteristics over prolonged periods of recording were similar for both groups, as were sinoaortic baroreflex activity and pressor response to isometric and dynamic exercise and to cold. Fasting cholesterol and triglyceride levels in both groups were similar. Resting plasma renin activity (PRA) was significantly lower in blacks, but no difference was observed in resting plasma norepinephrine levels. Urinary excretion of Na+ and K+ was also similar in both groups. Thus, results showed that casual BPs matched for black and whites, and recorded over a prolonged period, were similar in pattern, variability, and response to pressor stimuli. It appears that, if BP contributes to the different patterns of morbidity in blacks and whites, it is more likely to be the actual level of BP rather than differences in BP characteristics. (Hypertension 4: 817–820, 1982)

Felodipine in hypertension

SummaryFelodipine, a selective arteriolar dilator, was given to 13 hypertensive patients to assess its hypotensive effects and duration of action. Nine patients were treated with 5 mg three times a day and 4 with 10 mg three times a day.Mean blood pressures fell with both treatment regimens: 5 mg placebo 170/103 mmHg; 5 mg felodipine 148/91 mmHg; 10 mg placebo 154/93 mmHg; 10 mg felodipine 137/82 mmHg.Heart rates increased as blood pressures fell with both treatments. However, in the patients given 5 mg three times a day this effect was less noticeable after successive doses.Plasma concentrations of noradrenaline, both resting and tilted, increased after felodipine. There was a negative correlation between the fall in blood pressure and the increase in noradrenaline, suggesting that those patients with good baroreceptor reflexes were better able to counteract the effects of vasodilatation.Four of the nine patients treated with 5 mg felodipine three times a day experienced mild and transient adverse effects. Of the four patients treated with 10 mg three times a day, three experienced moderate to severe headache, and for this reason recruitment into this group was stopped.Felodipine at a divided daily dose of 15 mg effectively lowered blood pressure.

Continuous ambulatory monitoring of blood pressure and assessment of cardiovascular reflexes in the elderly hypertensive.

Thirteen elderly hypertensives underwent continuous ambulatory blood pressure (BP) monitoring and measurement of cardiovascular reflexes. The results were compared with elderly normotensives and young hypertensives studied using the same protocol. There was a greater disparity between casual systolic BP (SBP) and ambulatory awake SBP in the elderly hypertensives than either the elderly normotensives or young hypertensives. Variability of SBP was greater in the elderly than the young, whilst baroreflex activity was reduced in the elderly, and more markedly so in the elderly hypertensives. Response to tilt and pressor tests was similar for the elderly. The elderly hypertensives showed a greater fall of SBP in response to tilt and a greater rise of SBP during dynamic exercise than the young hypertensives. Stimulation of plasma renin activity (PRA) in response to upright tilt was less in the elderly hypertensives than the young hypertensives. Resting plasma noradrenaline (PNA) increased with age.

Effects of perindopril on ambulatory intra-arterial blood pressure, cardiovascular reflexes and forearm blood flow in essential hypertension.

The effects of monotherapy with the angiotensin converting enzyme (ACE) inhibitor perindopril (8mg once daily) on 24-h ambulatory intra-arterial blood presure, forearm blood flow, left ventricular mass, vasoactive hormones and cardiovascular reflexes were determined in eight hypertensive patients using a randomized, double blind, placebo-controlled, cross-over protocol. Six weeks of perindopril treatment was associated with a significant reduction of ambulatory blood pressure and a significant increase in forearm blood flow. Whilst the haemodynamic responses to Valsalvas manoeuvre, tilt, isometric forearm exercise and cold pressor testing were unaffected by perindopril, significant augmentation of the bradycardia during facial immersion was seen after chronic therapy. Sino-aortic baroreceptor-heart rate reflex resetting was apparent within 2h of the first dose; this effect persisted throughout the active treatment period. Withdrawal of treatment was associated with a persisting hypotensive effect and an increase in heart rate which was not accompanied by an increase in plasma catecholamines. We conclude that perindopril, in a dose of 8mg once daily, was an effective antihypertensive agent. We postulate that chronic therapy was associated with a sustained increase in parasympathetic tone.

Once daily indapamide in the treatment of the elderly and young hypertensive

SummaryNine elderly and 11 young hypertensives underwent continuous ambulatory monitoring of blood pressure (BP), assessment of cardiovascular reflexes and M-mode echocardiography as hospital in-patients prior to treatment with once-daily indapamide (2.5 mg). They were followed as out-patients for 4 months during which time casual BP was measured at monthly intervals. The patients were then readmitted to hospital and studied using the same protocol under similar standardised conditions. The results showed that indapamide reduced casual and ambulatory BP in both young and elderly although the most marked effect was seen on systolic BP. Assessment of cardiovascular reflexes indicates that at least part of the hypotensive action of indapamide is due to a diuretic effect. Treatment with indapamide has comparable results on both young and elderly.

Effect of unrestricted activity on accuracy of ambulatory blood pressure measurement.

A validation study of the Takeda TM-2420 ambulatory blood pressure recorder was performed on 10 subjects using the Oxford ambulatory intra-arterial recording apparatus during unrestricted activity. Electronic linkage of the two recorders ensured simultaneous blood pressure readings, taken from opposite arms. Although there was close approximation of intra-arterial and automated sphygmomanometric recordings over the range of blood pressure encountered in this study, there was a wide scatter of points and a tendency for the machine to underestimate systolic pressure by more than 15 mm Hg in the hypertensive range (systolic blood pressure more than 160 mm Hg) was detected. These findings suggest that automated recording of blood pressure during unrestricted activity may have a proportion of artifactual readings. Although simultaneous intra-arterial blood pressure recording may not be appropriate for widespread use in device validation, this study illustrated some potential disadvantages of the current validation recommendations, namely, the absence of assessment of device accuracy during unrestricted and ambulatory activity.

Intra-arterial blood pressure and cardiovascular responses in black and white hypertensives

Sixteen black hypertensive patients were matched for age, sex, casual blood pressure and socio-economic status with 16 white hypertensives. All patients underwent continuous intra-arterial ambulatory monitoring of blood pressure, assessment of baroreflex activity and pressor response to exercise and cold. No differences were observed in the blood pressure and cardiovascular responses between the group.