Self-monitoring of Blood Pressure in Patients With Hypertension-Related Multi-morbidity: Systematic Review and Individual Patient Data Meta-analysis

BACKGROUND

Studies have shown that self-monitoring of blood pressure (BP) is effective when combined with co-interventions, but its efficacy varies in the presence of some co-morbidities. This study examined whether self-monitoring can reduce clinic BP in patients with hypertension-related co-morbidity.

METHODS

A systematic review was conducted of articles published in Medline, Embase, and the Cochrane Library up to January 2018. Randomized controlled trials of self-monitoring of BP were selected and individual patient data (IPD) were requested. Contributing studies were prospectively categorized by whether they examined a low/high-intensity co-intervention. Change in BP and likelihood of uncontrolled BP at 12 months were examined according to number and type of hypertension-related co-morbidity in a one-stage IPD meta-analysis.

RESULTS

A total of 22 trials were eligible, 16 of which were able to provide IPD for the primary outcome, including 6,522 (89%) participants with follow-up data. Self-monitoring was associated with reduced clinic systolic BP compared to usual care at 12-month follow-up, regardless of the number of hypertension-related co-morbidities (−3.12 mm Hg, [95% confidence intervals −4.78, −1.46 mm Hg]; P value for interaction with number of morbidities = 0.260). Intense interventions were more effective than low-intensity interventions in patients with obesity (P < 0.001 for all outcomes), and possibly stroke (P < 0.004 for BP control outcome only), but this effect was not observed in patients with coronary heart disease, diabetes, or chronic kidney disease.

CONCLUSIONS

Self-monitoring lowers BP regardless of the number of hypertension-related co-morbidities, but may only be effective in conditions such obesity or stroke when combined with high-intensity co-interventions.

Frovatriptan for The Prevention of Postdural Puncture Headache

Efficacy of 5–day treatment with oral frovatriptan 2.5 mg/die for the prophylaxis of post-dural puncture headache (PDPH) was tested in 50 in-patients. A mild headache occurred in 7 (14%) patients for a total of 9 days (p < 0.01 vs. no-PDPH). Most episodes of PDPH occurred in the first days of treatment (only 1 patient had headache at dismissal): 5 patients had only 1 episode, while 2 had headache for 2 consecutive days. No other symptoms were recorded. Occurrence of PDPH in a subgroup of 6 (12%) patients previously submitted to a diagnostic lumbar puncture was also examined: 4 of them reported a PDPH on the previous lumbar puncture in absence of triptans. In only 1 of these 4 patients PDPH recurred under treatment with frovatriptan. In conclusion, our non-randomized open-label study suggests efficacy of oral frovatriptan for PDPH prevention. These results need to be confirmed in a randomized, controlled, double-blind study.

Circadian blood pressure profile in patients with active Cushing's disease and after long-term cure

Hypertension is a major feature of Cushing's disease, with the attendant increase in the rate of cardiovascular events. The circadian blood pressure profile also impacts cardiovascular risk and a few studies have shown that patients with Cushing's syndrome do not present the expected nocturnal blood pressure decrease and, further, that this alteration persists in short-range disease remission. These studies were performed by conventional discontinuous ambulatory pressure monitoring, a technique not devoid of limitations. Aim of our study was the assessment of blood pressure and heart rate profile by beat-to-beat noninvasive monitoring in twelve patients with active Cushing's disease (9 women and 3 men, age 33.3+/-2.36 years) and the assessment of its possible changes at short- (<1 year) and long-term (2-3 years) follow-up after curative surgery. No nocturnal blood pressure dipping (i.e., decrease by 10% of daytime values) was observed in 50% of patients both during active hypercortisolism and within 1 year from surgery. Recovery of blood pressure dipping profile was detected at long-term follow-up in a minority of patients. Daytime heart rate was higher in patients with active Cushing's disease and decreased over time after cure. In conclusion, patients with Cushing's disease present absent nocturnal blood pressure dipping and abnormal heart rate values which do not resolve after short-term remission of hypercortisolism and show only partial improvement in the long run. These findings identify additional cardiovascular risk factors for patients cured of Cushing's disease.

A smooth blood pressure control is obtained over 24 h by delapril in mild to moderate essential hypertensives

OBJECTIVE

To assess the homogeneity of the antihypertensive effect of delapril over 24 h.

DESIGN AND METHODS

After 2 weeks of placebo 50 mild to moderate essential hypertensives (age 54+/-5 years) were subjected to 8 weeks of treatment with delapril 30 mg once daily. At the end of each period, blood pressure (BP) was assessed by conventional sphygmomanometry (clinic or CBP) and ambulatory (A) BP monitoring. Twenty-four-hour means, trough-to-peak ratio (T/P) and smoothness index (SI, the ratio between the average of the 24-h BP changes after T and its standard deviation) were calculated for systolic (S) and diastolic (D) BP.

RESULTS

CBP and ABP were significantly reduced by treatment. Pulse pressure (PP, the SBP-DBP difference) was also significantly (p < 0.01) reduced by delapril (5.7+/-6.2 and 3.3+/-3.8 mmHg, CPP and APP). The median T/P was higher (0.51 and 0.62, SBP and DBP) in the 43 responders at trough than in the whole group (0.44 and 0.51). The SI was similarly high in the whole group (1.3+/-0.6 and 1.4+/-0.6, SBP and DBP) and in the responders (1.4+/-0.5 and 1.5+/-0.6).

CONCLUSIONS

Delapril effectively and smoothly reduces BP over 24 h, this effect being evident also on PP, a parameter with a relevant prognostic value.

Mechanisms underlying the impairment in orthostatic tolerance after nocturnal recumbency in patients with autonomic failure

In the present study, we have assessed in patients with neurogenic orthostatic hypotension the haemodynamics underlying the reduced tolerance to standing after prolonged recumbency at night. In 10 patients with neurogenic orthostatic hypotension (age 33-68 years), of which seven were being treated with fludrocortisone and/or sleeping in the 12 degrees head-up tilt position, 24 h continuous non-invasive finger blood pressure was recorded by a Portapres device. Beat-to-beat blood pressure, heart rate, stroke volume, cardiac output and total peripheral vascular resistance obtained by pulse contour analysis were assessed during 5 min of standing in the evening (at 22.30 hours) and in the morning (at 06.30 hours). On average, the inverse of the normal 24 h blood pressure profile was found, with a large diversity in blood pressure profiles among patients. Supine blood pressure values were similar, but standing blood pressure values were lower in the morning than in the evening (P<0.01). This resulted from larger falls in stroke volume and cardiac output upon standing in the morning compared with the evening, while total peripheral resistance did not change. There was no relationship between the decrease in body weight during the night (mean 0.9 kg; range 0.2-1.6 kg) and the evening-morning difference in standing blood pressure. We conclude that, in patients with neurogenic orthostatic hypotension, the impaired tolerance to standing in the morning is due to larger falls in stroke volume and cardiac output. Not only nocturnal polyuria, but also a redistribution of body fluid, are likely mechanisms underlying the pronounced decreases in stroke volume and cardiac output after prolonged recumbency at night.

Relation between blood pressure variability and carotid artery damage in hypertension: baseline data from the European Lacidipine Study on Atherosclerosis (ELSA)

BACKGROUND

Baseline data from the European Lacidipine Study on Atherosclerosis (ELSA) have shown that carotid intima-media thickness (IMT) is not related to diastolic blood pressure (BP), but that it is related to clinic systolic (S) or pulse pressure (PP) and more so to their 24 h average values. The aim of the present study was to determine whether IMT independently relates to additional information obtained through ambulatory BP, in particular to SBP or PP variability.

METHODS AND RESULTS

In 1663 hypertensive patients, after a wash-out period from antihypertensive treatment (mean age 56.2 +/- 7.65 years), IMT was assessed from 12 different carotid sites. Ambulatory BP measurements were performed every 15 min (day) and every 20 min (night). IMT values were positively related to 24 h, day and night average SBP and PP. There was some relationship of IMT with day-night or clinic-day SBP and PP differences. The most important finding, however, was that IMT values were related with 24 h SBP or PP standard deviation (P < 0.001), a measure of overall SBP or PP variability. The relationship was seen also by multiple regression analysis, the standard deviation for SBP or PP only following age and 24 h average SBP or PP in accounting for IMT values.

CONCLUSIONS

This is the first demonstration from a large database that not only average 24 h PP and SBP values, but also 24 h BP fluctuations, are associated with, and possibly determinants of, the alterations of large artery structure in hypertension.

Efficacy, tolerability, and impact on quality of life of long-term treatment with manidipine or amlodipine in patients with essential hypertension

This double-blind, multicenter trial compared antihypertensive efficacy, tolerability, and impact on quality of life of manidipine and amlodipine in patients with mild-to-moderate essential hypertension. Patients were randomly assigned to 48 weeks of once-daily manidipine, 10-20 mg, or amlodipine, 5-10 mg. Patients who did not respond to treatment after 12 weeks were also given enalapril, 10-20 mg, for the study's duration. The main efficacy end point was equivalence in sitting systolic (SiSBP) and diastolic (SiDBP) blood pressure reduction between the two drugs after 8 weeks (per protocol analysis). An intention-to-treat (ITT) analysis was performed in all patients with at least one efficacy determination during treatment. Quality of life was assessed by the "Subjective Symptoms Assessment Profile" (SSA-P) and "General Well-being Schedule" (GWBS), after 12 weeks of treatment. SiSBP reduction after 8 weeks was equivalent for manidipine (15.2 mm Hg, n = 227) and amlodipine (17.0 mm Hg, n = 219). The corresponding figure for SiDBP was 11.3 mm Hg for manidipine and 12.3 mm Hg for amlodipine. In the larger ITT population SiDBP was similarly and significantly reduced by manidipine (from 102 +/- 5 to 88 +/- 9 mm Hg, n = 241) and amlodipine (from 101 +/- 5 to 87 +/- 8 mm Hg, n = 240). Similar results were observed for SiSBP and standing SBP and DBP. Neither drug changed sitting or standing heart rate compared with baseline. SSA-P scores improved with manidipine but not amlodipine. GWBS total and partial scores increased more with manidipine than with amlodipine. Safety profile favored manidipine, which was associated with significantly less ankle edema than was amlodipine. This study shows for the first time that long-term treatment with the long-acting calcium channel blocker manidipine is as effective as treatment with amlodipine, has a better tolerability profile, and induces greater improvement in quality of life than amlodipine.

Twenty-four hour ambulatory blood pressure in the Hypertension Optimal Treatment (HOT) study

BACKGROUND AND AIMS

The Hypertension Optimal Treatment (HOT) study showed that when antihypertensive treatment reduces diastolic blood pressure well below 90 mmHg, there can be a further reduction of cardiovascular events, particularly myocardial infarction, with no evidence of a J-shaped curve at lower pressures. Office measurement, however, gives no information about blood pressure outside the office. This paper describes a HOT substudy in which patients underwent both office measurement and 24 h ambulatory blood pressure monitoring.

METHODS

The mean age of the substudy population was 62 +/- 7 years. Substudy patients were treated for a median period of 2 years. All received the dihydropyridine calcium antagonist felodipine, while some also received an ACE-inhibitor, a beta-blocker or a diuretic. Average 24 h, day and night ambulatory blood pressure values were computed at baseline (n = 277) and during treatment (n = 347): 112 patients had been randomized to a target office diastolic blood pressure <or= 90 mmHg, 117 to <or= 85 mmHg and 118 to <or= 80 mmHg. Additional analyses included computation of: (1) trough-to-peak ratio and (2) the smoothness index (the ratio between the average of the 24 hourly blood pressure reductions after treatment and its standard deviation).

RESULTS

Taking the subgroup as a whole, baseline 24 h average blood pressures (146 +/- 18/90 +/- 10 mmHg) were significantly and markedly lower than office blood pressures (170 +/- 14/105 +/- 3 mmHg, P < 0.01). Office, 24 h, day and night blood pressures were all significantly reduced by treatment, but there was a smaller fall in ambulatory, than in office pressures. The between group differences in office blood pressure were smaller than those observed in the overall HOT sample. Between-group differences in 24 h blood pressure were even smaller. Trough-to-peak ratios and smoothness indices were lowest in the highest blood pressure target group and highest in the lowest blood pressure target group. Office and ambulatory blood pressures were similar in the groups randomized to placebo (n = 170) or acetylsalicylic acid (n = 177).

CONCLUSION

In conclusion, in the HOT study, treatment reduced not only office but also ambulatory blood pressure throughout the 24 h. The reduction was less marked for ambulatory than for office blood pressure.

Comparison of candesartan versus enalapril in essential hypertension. Italian Candesartan Study Group

BACKGROUND

The objective of this study was to compare the antihypertensive efficacy and tolerability of candesartan cilexetil (CC) with that of enalapril (E) and placebo (P) in hypertensives by clinic and ambulatory blood pressure (BP).

PROCEDURES

The study was an Italian multicenter, randomized, double-blind, parallel group trial including 227 mild to moderate essential hypertensives (age range, 18 to 70 years). After 4 weeks of P, patients were randomized to 8 weeks of treatment with P or CC (4 mg) or E (10 mg) once daily, which was eventually increased to 8 mg and 20 mg once daily in nonresponders. At the end of each study phase, trough BP was measured by conventional sphygmomanometry and ambulatory BP was monitored over 24 h by a Spacelabs device. Analysis of 24-h BP profile included calculation of 24-h, daytime, nighttime, and hourly average values.

RESULTS

In the 178 patients evaluable per protocol, at the end of 8 weeks of treatment, trough systolic (S) and diastolic (D) BP were similarly reduced by both active treatments (13 +/- 12 and 10 +/- 7 mm Hg for CC and 14 +/- 12 and 10 +/- 7 mm Hg for E) and significantly more by both treatments than by P (6 +/- 11 and 7 +/- 8 mm Hg, P < .01 v CC and E). In the 85 patients with valid 24-h recordings reduction in 24-h BP was again similar for the two active groups. The antihypertensive effect was still evident during h 23 and 24 after the last dose for both active treatments (8 +/- 20 v 5 +/- 18 mm Hg for SBP and 4 +/- 12 v 6 +/- 13 mm Hg for DBP, CC v E, respectively) but not for P. Heart rate was not significantly modified by either active treatment. The incidence of adverse events was greater in the E than in the CC group.

CONCLUSIONS

Our study provides evidence that CC at a dose of 4 to 8 mg is as effective as E at a dose of 10 to 20 mg over 24 h, but is better tolerated than E.

The importance of blood pressure variability in hypertension

Use of ambulatory blood pressure monitoring (ABPM) techniques has revealed that blood pressure is characterized by a considerable degree of variability over a 24 h period as a result, not only of the well-known fluctuations that occur between wakefulness and sleep, but also of the minute-to-minute changes induced by a variety of behavioural conditions. The degree of these variations is also influenced by neural mechanisms responsible for cardiovascular regulation, such as the arterial baroreflex. Blood pressure variability increases with age and blood pressure values, and its magnitude has been shown to correlate independently with the target-organ damage of hypertension. This has stimulated both the development of antihypertensive drugs able to reduce blood pressure homogeneously over 24 h, and recent proposals to develop more accurate indices, such as the smoothness index, to quantify the distribution of the antihypertensive effect over the entire day and night. Despite the important information that ABPM can provide concerning daily-life blood pressure variations and their modification by treatment, international guidelines suggest that it should not yet be used routinely in daily practice, but rather reserved for selected patients.

Antihypertensive efficacy of manidipine and enalapril in hypertensive diabetic patients

Recent studies showed that in diabetic hypertensive patients, administration of angiotensin-converting enzyme (ACE)-inhibitors or calcium antagonists can effectively lower blood pressure (BP) and prevent diabetes-related cardiovascular complications with no adverse metabolic effects. We sought to assess the antihypertensive and metabolic effects of the new dihydropyridine calcium antagonist manidipine (M) in patients with diabetes mellitus and essential hypertension as compared with the ACE inhibitor enalapril (E). After 3 weeks of placebo, 101 (62 men; age range, 34-72 years) hypertensives with type II diabetes mellitus were randomized to M 10-20 mg or E 10-20 mg, od, for 24 weeks. At the end of the placebo period and the active-treatment phase, BP was measured with a mercury sphygmomanometer (office, O) and over the 24 h by ambulatory (A) monitoring. ABP recordings were analyzed to obtain 24-h, day (6 a.m. to midnight), and night (midnight to 6 a.m.) average systolic (S) and diastolic (D) BP and heart rate (HR) values. Homogeneity of the antihypertensive effect over the 24 h was assessed by the smoothness index [SI: i.e., the ratio between the average of the 24 hourly BP changes after treatment and the corresponding standard deviation (the higher the SI, the more uniform is the BP control by treatment over the 24 h]. The O SBP and DBP were significantly (p < 0.01) and similarly reduced by M (16 +/- 10 and 13 +/- 6 mm Hg, n = 49) and E (15 +/- 10 and 13 +/- 6 mm Hg, n = 45). The percentage of patients whose O DBP was reduced < or = 85 mm Hg (i.e., the value indicated to be the optimal DBP goal in diabetic hypertensives) was similar for M (37%) and E (40%). The reduction of 24-h BP also was similar between M (n = 38) and E (n = 38) for both drugs (systolic, 6 +/- 11 and 8 +/- 10 mm Hg; diastolic, 5 +/- 8 and 5 +/- 7; NS, M vs. E). The antihypertensive effect was distributed in a similar homogeneous fashion throughout the dosing interval, as shown by the similar SI values (M, 0.6 +/- 1.2 for SBP and 0.6 +/- 0.9 for DBP; E, 0.6 +/- 0.8 for SBP and 0.5 +/- 0.7 for DBP; NS, M vs. E). O and A HR were unchanged by either treatment. Markers of glucose and lipid metabolism and renal function were not significantly modified by treatment both with M and with E. In the diabetic hypertensives, M was as effective and metabolically neutral as the ACE-inhibitor E.

Broad-band spectral analysis of 24 h continuous finger blood pressure: comparison with intra-arterial recordings

The present study compares the spectral characteristics of 24-h blood pressure variability estimated invasively at the brachial artery level with those estimated by measurement of blood pressure at the finger artery using the non-invasive Portapres device. Broad-band spectra (from 3x10(-5) to 0.5 Hz) were derived from both finger and intra-brachial pressures recorded simultaneously for 24 h in eight normotensive and twelve hypertensive ambulant subjects. At frequencies lower than 0.07 Hz, higher spectral estimates were obtained by Portapres than by intra-brachial measurements. The maximum overestimation occurred in systolic pressure at around 10(-2) Hz, where the amplitude of the oscillations was two times greater when measured by Portapres. A less pronounced overestimation was found for diastolic pressures. The maximum overestimation was greater during daytime than during night-time. At around 0.1 Hz, invasive and non-invasive spectra were similar. At the respiratory frequencies (0.15-0.50 Hz), the power spectra were overestimated by Portapres during daytime, and underestimated at night. These results provide reference information for the correct interpretation of Portapres data in the estimation of 24-h blood pressure spectral power.

Ambulatory blood pressure monitoring

This paper will briefly summarize the available evidence on the diagnostic and prognostic relevance of a number of parameters derived from the analysis of 24 hour ambulatory blood pressure recordings. These parameters include the 24 h average blood pressure values, the difference between daytime and nighttime blood pressure, the difference between clinic blood pressure and daytime average blood pressure as a surrogate measure of the "white coat effect", and 24 hour blood pressure variability as quantified by the standard deviation of the 24 hour average value.

Clinical advantages of lipophilic dihydropyridines

Lipophilic dihydropyridines have many theoretical and practical clinical advantages owing to their long permanence at the cell membrane. They have a greater chance of smoothly and permanently reducing blood pressure over 24 h than other dihydropyridines, a feature that may have positive prognostic implications since 24-h blood pressure is more closely related to the end-organ damage of hypertension. They may avoid the sympathetic activation consequent to an excessive early-dose hypotension, which is responsible for an increase in 24-h blood-pressure variability and reflex tachycardia, two phenomena that may worsen the prognosis of hypertensive patients. A further advantage which has been shown in experimental and clinical settings is the possibility of reducing the extension and progression of atherogenic lesions in blood vessels, which are responsible for cardiovascular complications in hypertension. Some of these features have been shown by the novel lipophilic dihydropyridine lercanidipine. In particular, clinical studies have shown that (i) this drug is effective in homogeneously reducing blood pressure over 24 h, (ii) its antihypertensive effect is similar to that of some common antihypertensive drugs, and (iii) the rate of adverse events experienced with lercanidipine is no greater than that observed with other antihypertensive drugs, with special reference to non-lipophilic calcium antagonists. In particular, studies performed so far have shown that lercanidipine does not exert a dangerous reflex tachycardia.

Antihypertensive efficacy of lercanidipine at 2.5, 5 and 10 mg in mild to moderate essential hypertensives assessed by clinic and ambulatory blood pressure measurements. Multicenter Study Investigators

OBJECTIVE

To evaluate the antihypertensive effect of lercanidipine once a day at three different doses (2.5, 5 and 10 mg) by clinic and ambulatory blood pressure.

METHODS

After 3 weeks of a placebo run-in, 243 mild to moderate essential hypertensives (mean+/-SD age 51+/-8 years) were randomly allocated to lercanidipine at 2.5, 5 or 10 mg or a placebo for 4 weeks, in a double-blind parallel-group design. At the end of each period, supine clinic blood pressure (standard sphygmomanometry) and 24 h ambulatory blood pressure (Spacelabs 90207) were measured. The duration and homogeneity of the antihypertensive effect of the active drug compared with placebo over 24 h was evaluated by calculating the smoothness index, the ratio of the mean of the 24 hourly blood pressure changes to the corresponding SD. The higher the smoothness index, the greater and the smoother is the antihypertensive effect of a drug over the 24 h.

RESULTS

In 211 patients with valid clinic blood pressure data at the end of treatment, larger systolic/diastolic blood pressure reductions were found in the 5 mg (10+/-12/8+/-6 mmHg; P< 0.05 versus placebo, diastolic blood pressure only) and the 10 mg (12+/-11/9+/-7 mmHg; P < 0.05 versus placebo, both pressures) lercanidipine groups than in the placebo (5+/-11/4+/-8 mmHg) and 2.5 mg lercanidipine (7+/-12/6 +/-7 mmHg) groups. In 105 patients with complete 24 h ambulatory blood pressure recordings, there were significantly (P< 0.05 versus placebo) larger reductions in the 10 mg (9+/-7/7+/-5 mmHg) than the 2.5 mg (1+/-10/1+/-6 mmHg) and placebo (2+/-6/1+/-4 mmHg) groups. The reduction in 24 h blood pressure with 5 mg lercanidipine (6+/-7/4+/-5 mmHg) was significantly greater compared with placebo for diastolic pressure only, and when hourly average blood pressure changes were considered, this reduction did not extend to the final hours of the dosing interval. No significant changes in the clinic or 24 h heart rate were induced by placebo or lercanidipine. The smoothness index was significantly (P< 0.05) lower for 2.5 mg lercanidipine and placebo (0.2+/-0.5 and 0.3+/-0.7 for systolic and 0.1+/-0.4 and 0.2+/-0.7 for diastolic blood pressure) than for the 5 and 10 mg doses (0.7+/-1 and 1+/-0.7 for systolic and 0.7+/-1 and 1+/-0.9 for diastolic blood pressure).

CONCLUSIONS

At a dose of 10 mg, lercanidipine had a significant and durable antihypertensive effect over 24 h, but at 5 mg, the effect was less consistent and did not last 24 h. There was no clinically relevant reduction in clinic or ambulatory blood pressure with 2.5 mg lercanidipine, and the effect was superimposable on that of placebo.

The smoothness index: a new, reproducible and clinically relevant measure of the homogeneity of the blood pressure reduction with treatment for hypertension

OBJECTIVE

To introduce a new method, the smoothness index, for assessing the homogeneity of 24 h blood pressure reduction by antihypertensive treatment and to compare it with the trough : peak ratio; and to assess the ability of both indices to predict a reduction in the left ventricular mass index induced by treatment.

PATIENTS AND METHODS

In 174 patients with essential hypertension and left ventricular hypertrophy, enrolled in the Study on Ambulatory Monitoring of Pressure and Lisinopril Evaluation (SAMPLE), aged 20-65 years, we measured clinic blood pressure, 24 h ambulatory blood pressure and the left ventricular mass index (echocardiography) before and after treatment with lisinopril at 20 mg with the addition of 12.5 or 25 mg hydrochlorothiazide as needed to reach a sufficient blood pressure reduction. The following parameters were computed for systolic and diastolic ambulatory blood pressure: (1) hourly and 24 h blood pressure averages (+/- SD) at baseline and after 3 and 12 months of treatment; (2) hourly blood pressure changes from baseline after 3 and 12 months of treatment, and their average (+/- SD) over 24 h; (3) the trough : peak ratio after 3 and 12 months of treatment; and (4) the smoothness index after 3 and 12 months of treatment Similar calculations were also performed at the end of a final study month during which active treatment was withdrawn and placebo was substituted (n = 164).

RESULTS

The smoothness index for systolic and diastolic ambulatory blood pressure computed after 3 months of treatment was more closely related to its corresponding values after 12 months of treatment than the trough : peak ratio values computed after the same time periods were (r = 0.68 versus 0.38 for systolic and 0.68 versus 0.42 for diastolic blood pressure, respectively). The smoothness index showed an inverse correlation with the 24 h standard deviation of systolic and diastolic blood pressure (r = -0.25 and -0.16, P < 0.01 and < 0.05, respectively, for 12 months of treatment), while the trough : peak ratio did not (r = -0.01 to -0.12, NS). A treatment-induced reduction in the left ventricular mass index was related to the smoothness index for systolic and diastolic blood pressure (r = -0.35 and -0.32, P< 0.001 with 12 months of treatment), but not to the corresponding trough : peak ratios.

CONCLUSIONS

The smoothness index identifies the occurrence of a balanced 24 h blood pressure reduction with treatment and correlates with the favourable effects of treatment on left ventricular hypertrophy better than the commonly used trough : peak ratio.

Clinical benefits of a consistent reduction in blood pressure

This paper briefly reviews the epidemiological evidence that hypertension is a major cardiovascular risk factor. It also summarizes the data from controlled intervention trials that show antihypertensive treatment to be accompanied by a reduction in cardiovascular morbidity and mortality. The inability of antihypertensive treatment to offer full protection to the hypertensive individual is then discussed, together with the therapeutic strategies to increase the benefits, particularly with respect to limiting end-organ damage and reduction of cardiovascular events. In this context, emphasis is given to the potential additional benefit conferred by control of 24-h blood pressure and to the compliance advantage of using drugs with a long duration of action. The longevity of the blood pressure lowering effect can compensate for delayed or missed drug consumption, a frequent phenomenon in the chronically treated hypertensive patient.

Reproducibility and clinical value of the trough-to-peak ratio of the antihypertensive effect: evidence from the sample study

The objectives of our study were to assess the reproducibility of the trough-to-peak ratio (T/P) and to see whether a high T/P is accompanied by more organ protection or vice versa. The study included 175 (mean+/-SD age, 51+/-9 years) subjects with mild-moderate essential hypertension who had echocardiographic evidence of left ventricular (LV) hypertrophy taken from the SAMPLE study (Study on Ambulatory Monitoring of Blood Pressure and Lisinopril Evaluation), an open-label multicenter study. The study included a 3-week washout pretreatment period, a 12-month treatment period with lisinopril (n=84) or lisinopril plus hydrochlorothiazide (n=91) once daily, and a 4-week placebo follow-up period. Results of 24-hour ambulatory blood pressure monitoring and echocardiographic determination of left ventricular mass index (LVMI) were obtained before and after 3 and 12 months of treatment. T/Ps were computed in each patient by dividing the systolic and diastolic blood pressure changes at trough (changes in the last 2 hours of the monitoring period) by those at peak (average of the 2 adjacent hours with the maximal blood pressure reduction between the 2nd and 8th hour from drug intake) after 3 and 12 months of treatment. Average 24-hour blood pressure was similarly reduced at 3 and 12 months. Trough blood pressure changes at 3 and 12 months were closely correlated, as were the corresponding peak blood pressure changes. However, the 3- and 12-month T/Ps correlated to a lesser degree (r<0.42). Furthermore, the reduction of LVMI induced by treatment was similarly correlated with the treatment-induced reduction in 24-hour average, trough, and peak blood pressures but not with the T/Ps. This was also evident when the contribution to LV hypertrophy regression by 24-hour blood pressure changes and T/Ps was assessed in a multivariate regression analysis. In patients with a T/P >/=0.5 or <0.5, the regression of LVMI was similar. In conclusion, peak and trough blood pressure changes are reproducible and predict the regression of LVMI induced by treatment as well as average 24-hour blood pressure. T/Ps are less reproducible, and their value does not predict regression of organ damage by antihypertensive treatment.

Estimation of blood pressure variability from 24-hour ambulatory finger blood pressure

Portapres is a noninvasive, beat-to-beat finger blood pressure (BP) monitor that has been shown to accurately estimate 24-hour intra-arterial BP at normal and high BPs. However, no information is available on the ability of this device to accurately track ambulatory BP variability. In 20 ambulatory normotensive and hypertensive subjects, we measured 24-hour BP by Portapres and through a brachial artery catheter. BP and pulse interval variabilities were quantified by (1) the SDs of the mean values (overall variability) and (2) spectral power, computed either by fast Fourier transform and autoregressive modeling of segments of 120-second duration for spectral components from 0.025 to 0.50 Hz or in a very low frequency range (between 0.00003 and 0.01 Hz) by broadband spectral analysis. The 24-hour SD of systolic BP obtained from Portapres (24+/-2 mm Hg) was greater than that obtained intra-arterially (17+/-1 mm Hg, P<0.01), but the overestimation was less evident for diastolic (3+/-1 mm Hg, P<0.01) and mean (3+/-1 mm Hg, P<0.01) BP. The BP spectral power <0.15 Hz was also overestimated by Portapres more for systolic than for diastolic and mean BPs; similar findings were obtained by the fast Fourier transform, the autoregressive approach, and focusing on the broadband spectral analysis. BP spectral power >0.15 Hz obtained by the Portapres was similar during the day but lower during the night when compared with those obtained by intra-arterial recordings (P<0.01). No differences were observed between Portapres and intra-arterial recordings for any estimation of pulse interval variabilities. The overestimation of BP variability by Portapres remained constant over virtually the entire 24-hour recording period. Thus, although clinical studies are still needed to demonstrate the clinical relevance of finger BP variability, our study shows that Portapres can be used with little error to estimate 24-hour BP variabilities if diastolic and mean BPs are used. For systolic BP, the greater error can be minimized by using correction factors.

Reproducibility and clinical value of nocturnal hypotension: prospective evidence from the SAMPLE study. Study on Ambulatory Monitoring of Pressure and Lisinopril Evaluation

OBJECTIVE

To assess whether modifications in the nighttime blood pressure fall caused by antihypertensive treatment predict the regression of end-organ damage of hypertension.

METHODS

The analysis was performed in patients with essential hypertension and echocardiographically detected left ventricular hypertrophy involved in the SAMPLE study. For each patient, ambulatory blood pressure monitoring and echocardiographic determination of left ventricular mass index were performed at the end of a 4-week wash-out pretreatment period, after 3 and 12 months of treatment with lisinopril or with lisinopril plus hydrochlorothiazide and after a final 4-week placebo period. For each ambulatory blood pressure monitoring the 24 h average, daytime average (0600-2400 h), night-time average (2400-0600 h) and day-night difference was computed. The percentages of dipper and non-dipper patients (i.e. the patients with night blood pressure falls greater and less than 10% of the daytime average, respectively) were also computed.

RESULTS

The reproducibility of the day-night difference was low, both for comparison of the pretreatment and final placebo periods (n = 170) and for comparison of the third and the 12th month of treatment (n = 180). The reproducibility of the dipper-non-dipper dichotomy was also low, 35-40% of patients becoming non-dippers if they were dippers and vice versa, both with and without treatment The changes in left ventricular mass index after 12 months of treatment were significantly (P<0.01) related to the changes in 24 h, daytime and night-time blood pressure (r always > 0.33), but this was not the case for the treatment-induced modification of the day-night difference (r= -0.03 and -0.008 for systolic and diastolic blood pressures, respectively).

CONCLUSIONS

Our results show that day-night blood pressure changes and the classification of patients into dippers and non-dippers are poorly reproducible over time. It also provides the first prospective evidence that treatment-induced changes in day-night blood pressure difference are not related to treatment-induced regression of left ventricular mass index, thus having a limited clinical significance.

Difference between clinic and daytime blood pressure is not a measure of the white coat effect

The purpose of the present study was to evaluate whether the difference between blood pressure measured in the clinic or physician's office and the average daytime blood pressure accurately reflects the blood pressure response of the patient to the physician ("white coat effect" or "white coat hypertension"). We studied 28 hypertensive outpatients (mean age, 41.8+/-11.2 years; age range, 21 to 64 years) of 35 consecutive patients attending our hypertension clinic, in whom (1) continuous noninvasive finger blood pressure was recorded before and during the visit, (2) blood pressure was measured according to the Riva-Rocci-Korotkoff method (mercury sphygmomanometer) with the patient in the supine position, and (3) daytime ambulatory blood pressure was monitored with a SpaceLabs 90207 device. The peak blood pressure increase recorded directly during the visit was compared with the difference between clinic and daytime average ambulatory blood pressures. Compared with previsit values, peak increases in finger systolic and diastolic blood pressures during the visit to the clinic were 38.2+/-3.1 and 20.7+/-1.6 mm Hg, respectively (mean+/-SEM, P<.01 for both). Daytime average systolic and diastolic blood pressures were 135.5+/-2.5 and 89.2+/-1.9 mm Hg, with both lower than the corresponding clinic blood pressure values (146.6+/-3.6 and 94.9+/-2.2 mm Hg, P<.01). These differences, however, were <30% of the peak finger blood pressure increases during the physician's visit, to which these increases showed no relation. Although the visit to the physician's office was associated with tachycardia (9.0+/-1.6 bpm, P<.01), there was no difference between clinic and daytime average heart rates. These data indicate that the clinic-daytime average blood pressure difference does not reflect the alerting reaction and the pressure response elicited by the physician's visit and thus is not a reliable measure of the white coat effect.

Limitations of the difference between clinic and daytime blood pressure as a surrogate measure of the 'white-coat' effect. Syst-Eur investigators

BACKGROUND

The difference between clinic and ambulatory average daytime blood pressures is frequently taken as a surrogate measure of the 'white-coat effect' (i.e. the pressor reaction triggered in the patient by the physician's visit).

OBJECTIVE

To assess the reproducibility of this difference and its relationship with clinic and average ambulatory daytime blood pressure levels.

DESIGN AND METHODS

These issues were addressed with two large groups of subjects in whom both clinic and ambulatory blood pressures were measured, namely 783 outpatients with systolic and diastolic essential hypertension [Group 1, aged 50.8+/-9.4 years (mean +/- SD)], participating in standardized Italian trials of antihypertensive drugs, and 506 elderly patients (group 2, age 71+/-7 years) with isolated systolic hypertension, participating in the European Syst-Eur trial.

RESULTS

The clinic-daytime blood pressure difference for the essential systolic and diastolic hypertensive patients (group 1) was 13.6+/-14.3 mmHg for systolic and 9.1+/-8.6 mmHg for diastolic blood pressure (P always < 0.01). This difference for the elderly patients with isolated systolic hypertension (group 2) was 21.2+/-16.0 mmHg for systolic and only 1.3+/-10.2 mmHg for diastolic blood pressure (P < 0.01 and P < 0.05, respectively). In both studies little or no systematic clinic-daytime difference could be observed for heart rate. The reproducibility of the clinic-daytime blood pressure difference, tested for 108 essential systolic and diastolic hypertensive patients from group 1 and 128 isolated systolic hypertensives from group 2, was invariably lower than that both of daytime and of clinic blood pressure values. Finally, the clinic-daytime blood pressure difference was progressively higher for increasing levels of clinic blood pressure and progressively lower for higher levels of ambulatory daytime blood pressure.

CONCLUSIONS

Thus, the clinic-daytime blood pressure difference has a limited reproducibility; depends not only on clinic but also on daytime average blood pressure, which means that its size is a function of the blood pressure criteria employed for selection of the patients in a trial; and is never associated with a systematic clinic-daytime difference in heart rate, which further questions its use as a reliable surrogate measure of the true pressor response induced in the patient by the doctor's visit.

[The difference between clinical ambulatory measured blood pressure and daily monitored pressure does not reflect the "white coat effect"]

The difference between clinic and average daytime ambulatory blood pressure is frequently used to identify patients with "white coat" hypertension (i.e. with a pronounced pressor response to the clinical evaluation) although there is no evidence that this difference is indeed due to a white coat effect. In 28 mild hypertensive outpatients, the blood pressure was continuously recorded by a noninvasive finger device before and during the doctor's visit. The peak blood pressure increase, recorded during the visit was compared with the difference between clinic and daytime average ambulatory blood pressure. Peak increases in systolic and diastolic finger blood pressure during the doctor's visit were 38.2 +/- 3.1 mmHg and 20.7 +/- 1.6 mmHg, respectively compared to pre visit values (means +/- standard error, both p < 0.01). Daytime average systolic and diastolic blood pressure were 135.5 +/- 2.5 mmHg and 89.2 +/- 1.9 mmHg, both being lower than the corresponding clinic blood pressure values (146.6 +/- 3.6 mmHg and 94.9 +/- 2.2 mmHg, p < 0.01). Their differences, however, were < 30% of the peak finger blood pressure increase during the physician's visit. While the physician's visit was associated with tachycardia (+9.0 +/- 1.6 b/min, p < 0.01) there was no difference between clinic and daytime average heart rate. The alerting reaction and the pressor response induced by the physician's visit is not reflected by the difference between clinic and daytime average blood pressure. Such a difference is not therefore a reliable measure of the white coat effect.

Hemodynamic changes in the lower limbs during treadmill walking in normal subjects and in patients with arteriosclerosis obliterans

The effects of arteriosclerosis obliterans on the hemodynamic changes that occur during walking are largely unknown. For this reason, the authors measured blood pressure by transducer from the posterior tibial artery and vein at both ankles in 23 patients with arteriosclerosis obliterans of different severity and at the left ankle in 8 normal subjects. Radial artery pressure was also measured, and the differences between mean radial and ankle arterial pressures (pressure gradient) and between mean arterial and venous ankle pressures (foot perfusion pressure) were calculated. All measurements were made simultaneously and continuously during standing, treadmill walking at five different speeds, and during recovery. Compared with the normal subjects, the patients exhibited a greater pressure gradient and lower ankle arterial pressure and foot perfusion pressure at rest. During walking and recovery these intergroup hemodynamic differences were markedly enhanced, and ankle venous pressure was lower in the patients than in the normal subjects. In the patients the hemodynamic pattern depended on disease severity at rest and on both disease severity and walking speed during walking and recovery.

Combination treatment in hypertension: the VeraTran Study

In the past few years, the combination of two antihypertensive drugs has become a popular approach to hypertension treatment, because this procedure allows one to obtain satisfactory blood pressure control when monotherapy is partially ineffective and also to improve a patient's adherence to the therapeutic regimen, thereby enhancing the tolerance/effectiveness ratio of the treatment. This paper will briefly review the theoretical background and the requirements for an effective combination treatment. It will also discuss the results of the VeraTran Study, a multicenter study performed according to a double-blind parallel group design and aimed at assessing the antihypertensive efficacy of the fixed combination verapamil slow release (SR) and trandolapril, administered for 8 weeks, on clinic and 24-h ambulatory blood pressure. The results of the study demonstrate that the fixed combination of a calcium antagonist and an angiotensin converting enzyme (ACE) inhibitor allows one to obtain an effective and balanced blood pressure control throughout the 24 h.

Assessment of antihypertensive treatment by ambulatory blood pressure

ADVANTAGES OF AMBULATORY BLOOD PRESSURE MONITORING: Ambulatory blood pressure monitoring is now used widely to assess the efficacy of antihypertensive drugs in daily life conditions. These 24-h measurements have a number of advantages compared to conventional sphygmomanometric readings. Although a small placebo effect is observed in the first few hours after placebo administration, 24-h average blood pressure is substantially devoid of any placebo effect. Moreover, ambulatory blood pressure is not affected by the alerting reaction usually observed during the doctor's visit. When the 24-h average value is considered, ambulatory blood pressure is more reproducible than clinic blood pressure. Finally, ambulatory blood pressure is prognostically more important than clinic blood pressure, since the end-organ damage associated with hypertension is more closely related to 24-h than to clinic blood pressure. Ambulatory blood pressure monitoring is therefore particularly useful when testing the efficacy of new antihypertensive agents on 24-h blood pressure. TESTING THE COMBINATION OF VERAPAMIL AND TRANDOLAPRIL: In a recent study we evaluated the efficacy of a fixed combination of verapamil and trandolapril using both clinic and ambulatory blood pressure measurements. Ambulatory blood pressure monitoring showed that the effect of the combination of verapamil and trandolapril was greater than the effect of either of the two drugs administered alone. However, the clinic blood pressure measurements failed to show any systemically greater effect with the combination versus monotherapy. This further indicates that ambulatory blood pressure is superior to conventional blood pressure in the assessment of antihypertensive drugs.

Performance of the AM-5600 blood pressure monitor: comparison with ambulatory intra-arterial pressure

The AM-5600 is a new device that simultaneously monitors electrocardiogram (ECG) and noninvasive blood pressure (BP) over a 24-h period. BP readings (Korotkoff sounds and cuff air pressure) are stored into the recorder, allowing the removal of BP artifacts after a visual check. In 12 subjects with essential hypertension, we compared BP values simultaneously provided by the AM-5600 and intra-arterial recordings. At rest, noninvasive systolic BP (SBP) values were lower (5.4 +/- 4.9 mmHg) and diastolic BP (DBP) values were higher (7.3 +/- 7.3 mmHg) than were intra-arterial values. In ambulatory conditions (9 subjects), between-method discrepancies were +0.8 +/- 6.1 and +12.2 +/- 7.4 mmHg for 24-h SBP and DBP, respectively. AM-5600 underestimated 24-h intra-arterial SBP and DBP SD, but it accurately tracked intra-arterial SBP and DBP changes. Editing removed 22.1% of total readings, slightly reducing between-method discrepancies. Thus the AM-5600 provides an accurate average estimate of resting and ambulatory SBP and, for DBP, a less accurate estimate that is slightly improved by editing. The AM-5600 allows accurate description of SBP and DBP profiles and thus may be suitable to describe the abrupt BP changes accompanying a number of clinical events.

Ambulatory blood pressure monitoring

PREDICTIVE VALUE OF 24-H AMBULATORY BLOOD PRESSURE MONITORING: Average 24-h blood pressure values are more closely related to the target-organ damage of hypertension than are clinic blood pressure readings. Preliminary evidence from longitudinal studies suggests that ambulatory blood pressure is also superior to isolated clinic readings in the prognostic evaluation of hypertensive patients. This is supported by the demonstration that in hypertensive patients with left ventricular hypertrophy, regression of cardiac hypertrophy following treatment was better predicted by the drug-induced reduction in 24-h average blood pressure than clinic blood pressure.

BLOOD PRESSURE VARIABILITY

Also, 24-h blood pressure variability seems to be involved in the genesis of hypertension target-organ damage, while the clinical value of specific components of the 24-h blood pressure profile, such the nocturnal blood pressure fall, is still a matter of debate. Similar caution is needed in approaching the clinical significance of white coat hypertension, the definition of which is still affected by important methodological problems.

Difference between office and ambulatory blood pressure and response to antihypertensive treatment

OBJECTIVE

To investigate whether a clinic-ambulatory blood pressure difference persists with time under active drug treatment or placebo and to determine whether and how it interferes with the evaluation of the efficacy of antihypertensive treatment.

DESIGN AND METHODS

In 382 mild or moderate essential hypertensive patients (mean age +/- SD 51.5 +/- 9.2 years) clinic and ambulatory (SpaceLabs 90207 device) blood pressures were measured twice, under baseline conditions and after 4-8 weeks of antihypertensive treatment by calcium antagonists or angiotensin converting enzyme inhibitors (n = 266) or of placebo administration (n = 116). In each patient the difference between clinic and daytime average blood pressure was taken as a surrogate measure of the magnitude of the 'white-coat effect', separately for systolic and diastolic blood pressures. The changes in this difference induced by treatment and by placebo and the relationship between the blood pressure changes induced by drug treatment and by placebo and the magnitude of the difference before and during treatment or placebo, respectively, were computed.

RESULTS

Before drug treatment, the difference was 16.6 +/- 13.6 and 10.1 +/- 7.9 mmHg for systolic and diastolic blood pressures, respectively. During treatment the corresponding values were 11.9 +/- 14.2 and 6.8 +/- 9.2 mmHg; both of the reductions were statistically significant. Both for systolic and for diastolic blood pressure, the reduction in clinic blood pressure caused by treatment was directly related to the clinic-ambulatory difference before treatment, but inversely related to the magnitude of that difference persisting during treatment. The clinic-ambulatory blood pressure difference observed before placebo was attenuated during placebo, the magnitude of the attenuation being similar to that found under drug treatment. No significant difference between clinic and daytime average heart rate was ever observed before and during active treatment or placebo.

CONCLUSIONS

A considerable clinic-ambulatory blood pressure difference persists during several weeks of antihypertensive treatment, but its magnitude is significantly attenuated. This leads to an overestimation of the effectiveness of antihypertensive treatment when this is assessed by clinic blood pressure measurements only. This overestimation is greater in subjects with an initially greater difference because in these subjects the subsequent attenuation is greater. Because similar phenomena are observed with placebo, the attenuation in the difference during drug treatment is likely to reflect merely habituation to clinic blood pressure measurements with time.

Blood pressure and heart rate variability in autonomic disorders: a critical review

Spectral analysis (SA) of blood pressure (BP) and heart rate (HR) fluctuations has been proposed as a unique approach to obtain a deeper insight into cardiovascular regulatory mechanisms in health and disease. A number of studies performed over the last 15 years have shown that autonomic influences are involved in the modulation of fast BP and HR fluctuations (with a period <1 min), particularly at frequencies between 0.2 and 0.4 Hz [high frequency (HF) region or respiratory frequency] and around 0.1 Hz [mid frequency (MF) region]. In patients with secondary or primary autonomic dysfunction, SA of BP and HR signals recorded at rest or during orthostatic challenge in a laboratory environment have shown the occurrence of a reduction in the power of MF and/or HF, BP and HR components. Such a reduction is associated or may even precede the clinical manifestation of autonomic neuropathy. However, the above results collected in standardized laboratory conditions cannot reflect the features of neural cardiovascular control during daily life in ambulant individuals with autonomic failure. To investigate this issue, SA techniques have been applied to 24 h beat-to-beat intra-arterial and non-invasive finger BP recordings obtained in elderly subjects and in pure autonomic failure patients, respectively. In these conditions, HR powers displayed a reduction over a wide range of frequencies (from 0.5 to below 0.01 Hz). Conversely, BP powers underwent a complex rearrangement characterized by a reduction in the power around 0.1 Hz and by an increase in the powers at the respiratory frequency and at frequencies below 0.01 Hz. Dynamic quantification of the sensitivity of the baroreceptor-heart rate reflex by combined analysis of systolic BP and pulse interval (i.e. the interval between consecutive systolic peaks) powers around 0.1 Hz (alpha technique) has shown that in elderly subjects, and even more so in pure autonomic failure patients, baroreflex sensitivity is markedly reduced over the 24 h, and is no longer characterized by its physiological day-night modulation. In conclusion, although in some instances SA of cardiovascular signals may fail to fully reflect the features of autonomic cardiovascular control, the evidence discussed clearly demonstrates that this approach represents a promising tool for a dynamic assessment of the early impairment of neural circulatory control in autonomic failure. This is particularly the case when these analyses are performed on 24 h continuous BP and HR recordings in ambulant subjects.