Simultaneous and sequential same-arm measurements in the validation studies of automated blood pressure measuring devices.

The oscillometric ambulatory blood pressure recorder Daypress 500 was validated according to the British Hypertension Society protocol. Both sequential and simultaneous measurements were used. Multiple regression analysis demonstrated a significant influence of subject pulse pressure and arm circumference on device-observer systolic pressure differences. Differences between observer consecutive readings were inversely related to heart rate. Device and observer blood pressure readings were closer at simultaneous than at sequential measurements. However, both kinds of measurement led to the same final evaluation (A for diastolic and B for systolic blood pressure), provided that the appropriate grading criteria were applied for each method.

Echocardiographic evaluation of children with and without family history of essential hypertension.

A family history of hypertension is considered a risk factor for developing hypertension. We studied two groups of normotensive children (aged 14 years): one comprising 14 subjects with family history of hypertension, the other comprising 15 subjects without family history of hypertension. Children were comparable with respect to age, weight, height, body surface area, heart rate, and arterial blood pressure. M-mode echocardiography demonstrated higher interventricular septum/posterior wall ratio in progeny of hypertensive subjects. Interestingly, all the parameters evaluated were within the normal limits. Our data suggest that a certain degree of cardiac changes is present in children with positive family history of hypertension, though further studies are needed before considering these findings predictive of future essential hypertension.

Self-measurement and ambulatory monitoring of blood pressure: a subject's chronobiological perspective.

Population studies show the direct benefit from self-measurement for guiding the treatment of patients with severe hypertension; they also separate groups of children with a positive vs. negative family history of high blood pressure, despite the difficulty of obtaining valid readings during the rest/sleep span, which are needed for a reliable estimation of the circadian parameters. From the viewpoint of preventive maintenance, a 67-year-old woman monitored her blood pressure and heart rate around the clock for 7 days, using concomitantly an ambulatory monitor and a manual instrument. Self-measurement profiles were repeated on several occasions. The results are compared with those of a 62-year-old woman who followed the same initial 7-day protocol. The estimation of the circadian blood pressure pattern differed between the profiles obtained with an ambulatory monitor and by self-measurement. The differences, relatively small in one subject, were much larger for the other subject. Provided the results are chronobiologically analyzed and interpreted in the light of reference limits which are specific to self-measurement series as well as for gender, age and times of sampling, systematic self-measurement of blood pressure may yield a reliable assessment of the circadian variation for some, but not for all, individuals. For those who have been validated in at least one 7-day/24-h profile, occasional automatic ambulatory profiles are tentatively recommended as the main approach, with complementary systematic self-measurement when automatic instruments are scarce. For those with discrepant results, automatic monitoring is invariably recommended.

Chronobiology of blood pressure.

The chronobiology of blood pressure is a useful tool for examining serial data to quantify the dynamics of variability. The implications and applications for diagnosis and therapy are discussed, with clinical examples. The chronobiological patterns of hypertension are described. Chronobiology can make a real contribution to the prevention of disease. Chronobiology helps diagnose circadian hyper-amplitude-tension (CHAT), a condition in which excessive circadian BP amplitude precedes chronic established hypertension.

Accelerated (malignant) hypertension: a study of 121 cases between 1974 and 1996.

A series of 121 consecutive cases with accelerated hypertension is presented. Forty-seven patients had essential hypertension. This diagnosis was confirmed during the follow-up, which lasted from 3 to 255 months (mean 63.1 +/- 58.1). The relationship between the effects of pharmacological treatment on high blood pressure (BP) and disease course were analyzed in accelerated essential hypertensive patients only, to avoid the imponderable influence of basic disease in secondary hypertension. In most cases, therapeutical effect on BP was monitored by multiple daily BP self-measurements. Since 1974, when this study was initiated, plasma creatinine concentration at admission showed a clear-cut decrease, especially after the introduction in the eighties of new hypotensive drugs. A sustained BP decrease assured a long-lasting preservation of renal function, if the initial functional loss was limited (plasma creatinine concentration of 2 mg/dl (176.8 mumol/l) or less). Renal function was preserved even if the BP decrease was not optimal and signs of relapsing malignant retinopathy were observed in the course of disease. Although the whole series showed a 12-year survival rate of about 69%, patients enrolled after 1980 had a 100% survival rate.

Hypertensive vascular crisis secondary to chronic total renal artery occlusion.

We have reviewed thirty-three cases of accelerated hypertension associated with chronic total renal artery occlusion. During the process of progressive narrowing of the arterial lumen until complete occlusion, an exceptionally elevated blood pressure occurs when a critical reduction of renal blood flow is attained. Then the patient presents one or more of the following clinical manifestations: III-IV grade KWB retinal changes, hypertensive encephalopathy including convulsive attacks, stroke, heart failure, renal insufficiency. We have called this clinical event 'hypertensive vascular crisis'. Mostly in older patients an actual or anamnestic vascular crisis makes a diagnosis of chronic total renal artery occlusion highly probable.

The antibody response in chronic pyelonephritis.

Serum antibodies specific for the bacteria isolated from the urines of 41 patients with chronic pyelonephritis and 14 with asymptomatic bacteriuria were assayed. Even though it is clear that infections which involve the kidney evoke higher antibody responses than do purely bladder infections, it is difficult to establish a cut-off level for distinguishing the two by this method. There is a greater probability that there will be an upper urinary tract infection without an antibody response than that there will be a good antibody response in cases with lower tract infections. In our case list, 49% of the patients with chronic pyelonephritis had titers equal to or greater than 1:400, and another 44% had titers between 1:50 and 1:100. Therefore it appears that the magnitude of the antibody response depends not only on the location of the infection but also on other factors, such as the intrinsic immunogenicity of the different bacterial strains and the properties of the immunological system of the patient.

Prazosin-induced haemodynamic modification in human hypertension. Evidence from strain-gauge plethysmography. Part II.

Three hypertensive in-patients responsive to a single oral administration of 1 mg prazosin were studied to compare the delays of drug effect on peripheral blood flow (PBF), heart rate (HR) and blood pressure (BP). Arm PBF was measured by venous occlusion strain-gauge plethysmography in a long run session (lasting at least 2 hours) every 5 - 10 minutes. HR and BP were measured accordingly, by conventional methods. The delays of the effect were compared by a cross correlation function of HR, systolic and diastolic BP versus PBF. The results show both advance and delay of HR increase as compared with PBF increase, suggesting some independent mode of action of prazosin at peripheral (vasodilation) and central (HR) level. BP decrease is instead always delayed with respect to PBF increase, by a variable amount (10 - 60 minutes) and with some difference in time response to systolic and diastolic BP, suggesting some independent feed-back loops controlling systolic and diastolic BP adjustment due to primary vasodilation effect.

Prazosin-induced vasodilatation of muscle blood vessels in human hypertension. Evidence from strain-gauge plethysmography. Part I.

The fall of blood pressure provoked in hypertensive men by a single oral dose of 1 mg of prazosin is associated with an increase of forearm muscle blood flow. This phenomenon may be demonstrated by a sequence of strain-gauge plethysmographic measurements, taken at regular intervals (5-10 minutes), before and during the action of the drug, lasting more than 2 hours.

Assessment of optimal dose of diuretic associated with fixed dose of beta-blocking: a new experimental model based on multiple sampling of blood pressure performed by self-measurements.

A new experimental model is presented for determining the optimum dose of 3 different doses (13 mg, 25 mg, 37 mg per day) of hydrochlorothiazide employed to enhance hypotensive effect of 200 mg/day of metoprolol in human hypertension. The model takes into account the circadian variability of blood pressure as sinusoidal function and wash-out effect as a linear trend so as to compensate for bias due to normal temporal variability.

Peripheral small vessel involvement in chronic nephritides.

Small cutaneous vessels, obtained by ear lobe biopsies, were studied in 14 patients with various chronic nephritides and in 10 normal controls. The capillaries in the group of patients with nephritis were found to undergo two main changes: thickening of the adventitia reticularis and perivascular cellular infiltration in an inverse ratio. This infiltration was seen to be made up of mononuclear cells and an increased number of mast cells in various stages of degranulation. Changes in the basement membrane as seen by electron microscopy are not constant. All of the above changes were absent in the controls and are similar to what has been described in previous studies in both experimental and spontaneous pathologic conditions, such as experimental hypertension, diabetes mellitus, scleroderma, rheumatoid arthritis, etc. Small vessel involvement in chronic nephritides could be part of a process of diffuse microvascular damage that includes the kidneys or it may be related to hypertension or to the biochemical changes which follow uremic and pre-uremic states.

Autorhythmometry in hypertension: some methodological aspects and clinical implications.

Autorhythmometry of blood pressure is a technique easy to be performed and well accepted by hypertensive patients. A simple inspection of data self-collected 5 times a day for many days constitute a sufficiently reliable automonitoring of blood pressure both in basal conditions and in relation to the efficacy of some dietary and/or pharmacological treatment. Several examples are reported to show that more sophisticated statistical manipulation of the data collected may give rise to a better understanding of some clinical and physiological aspects. Both analysis of variance, performed on individual subsets of data averaged at each sampling hour, and single cosinor, performed on longitudinal time series, may be used to detect and quantify a circadian rhythm as a systematic daily variation, averaging towards zero the noise superimposed to the actual time series. Serial section analysis of the data, along all the experimental span, is useful to detect a) the reproducibility of the rhythm b) the variation of its parameters induced by changes in the experimental conditions c) the long-term trend. In the first subject the influence on the circadian rhythm of the pulse rate, temperature and blood pressure, due to a 4 h advancing shift in the rest-activity synchronizer, is well documented. In the first hypertensive patient a circadian rhythm is demonstrated also in blood pressure during two non-consecutive months. No difference is detected in both mesor and amplitude of blood pressure and a full resynchronization of the acrophase is achieved when a 1 h delaying shift in the rest activity synchronizer is imposed. In the second patient a well reproducible rhythm of systolic blood pressure and a low noise/signal ratio is documented by the serial section display. In the third patient the 'lability' of hypertention seems mainly due to salt sensitivity, as documented by the significant lowering of the mesor in the second experimental span, when a lowering of only 30 mEq/day in salt intake is imposed. The serial section better documents the salt-sensitivity of this patient, during a span when loading and depressing of salt intake is imposed. In the last patient the prompt effect of therapy in lowering blood pressure within normal range is well documented by serial section with 3 day interval. A possible effect of masking the circadian rhythm of blood pressure, due to therapy, is inferred by the serial section display with an interval of the same length (33 days) as the subspan without therapy. The possibility of prevention in the hypertensive disease is discussed, with the aim of autorhythmometry and statistical methods employed in this paper.

The close interrelationship between increased vascular retinal permeability and blood pressure level. Evidence from retinal fluorangiography.

A long-term study was done by means of interative fluorangiography on microvascular retinal permeability versus the blood pressure control carried out in 11 patients with a diastolic blood pressure of greater than or equal to 130 mm Hg and with retinal exudates, haemorrhages and oedema. No matter what the original disease was (i.e., essential, renovascular, endocrine hypertension or chronic nephropathy with terminal renal failure) the increased permeability appeared to be critically connected with the blood pressure level. Our results confirm that hypertension per se might be the cause of vascular permeability changes.

Autometrically and automatically monitored, iatrogenous, inhalant-decongestant-associated high blood pressure quantified by rhythmometry.

Blood pressure and heart rate were oscillometrically monitored with an automatic Nippon Colin instrument (Komaki, Japan) and were also self-measured by a 20-year-old man treated with an inhalant-decongestant containing an adrenergic and a corticosteroid analog. The subject also collected 24-hr urines for aldosterone determination. An elevation of urinary aldosterone excretion was observed compared to the usual value range of a peer group. After removal of the drug, urinary aldosterone dropped as did urinary potassium, whereas plasma potassium rose. Chronobiologic serial sections, carried out to follow the time course of blood pressure and heart rate, showed decreasing trends in MESOR after discontinuance of treatment. A decrease in the hyperbaric index, a measure of blood pressure excess over 24 hr, was also observed. Another subject treated with the same and a third treated with a similar inhalant-decongestant, who also monitored their blood pressures automatically and/or with self-measurements, showed similar effects: a decrease in blood pressure after removal of treatment and an increase in blood pressure when (for testing only) treatment was briefly resumed.

Chronic total renal artery occlusion: a diagnostic challenge.

Chronic renal artery occlusion must be suspected whenever a moderate hypertensive patient over 50 years of age presents increase of blood pressure refractory to treatment, sometimes causing heart failure or stroke. This suspicion is reinforced by the presence of renal insufficiency and of anatomical and/or functional lateralization of renal damage at intravenous pyelography.

The maternal 24-h blood pressure (BP) profile as a predictor of fetal distress.

No mention is made of any aspect of BP bioperiodicity, among current clinical criteria for diagnosing pregnancy-related hypertension. The abnormal BP, based on a single unqualified measurement, is accepted and utilized as a clinical feature to identify pregnancy at risk. Systolic, diastolic and mean arterial blood pressure were measured every 15 min for 24 h in 5 women (2 non pregnant clinically healthy subjects, 1 clinically healthy subject in her third trimester of pregnancy, 1 presenting mild and 1 severe toxiemia, also in their third trimester of pregnancy) by an automated BP recording apparatus (Dynamap). All variables, analyzed by the single cosinor method, exhibited statistically significant circadian rhythms. A high amplitude could nullify the time-unqualified usual range. The change in circadian amplitude precedes an overt mesor hypertension and constitutes a tool for earlier detection of fetal distress.

A modified bladder washout test to improve diagnostic results in chronic urinary tract infections.

Bladder washout (BWO) and antibody-coated bacteria (ACB) tests were performed on 25 patients with radiological and/or clinical evidence of chronic upper urinary tract infection (UTI) and 12 patients with asymptomatic bacteriuria. Using a traditional single-washout procedure, the BWO test gave equivocal results in many cases of chronic pyelonephritis; this seemed mainly due to the lack of complete bladder sterilization. A modified procedure, including double sterilization and irrigation, biochemical typing of isolated bacteria, and evaluation of temporal pattern of bacteriuria recurrence, was then introduced. Although preliminary results of the modified BWO test demonstrated a general improvement in the diagnosis of the infection site, it seemed rather difficult, at least in chronic UTI, to establish localizing criteria based on definite numeric changes in bacterial counts after washout.