Can ambulatory blood-pressure monitoring provide reliable indices of arterial stiffness?

BACKGROUND: The use of ambulatory recordings of blood pressure (BP) was proposed to estimate arterial stiffness (AS). We compared the relative value of the ambulatory AS index (AASI), and of the slope of pulse pressure (PP) according to mean BP (MBP) obtained from 24-h ambulatory BP monitoring, to the monitoring of the arrival time of Korotkoff sounds (QKD interval) in the prediction of cardiovascular (CV) events. METHODS: Twenty-four-hour ambulatory BP and QKD monitoring were recorded at baseline, before antihypertensive treatment of hypertensive patients in our Bordeaux cohort. From these recordings, the AASI, the PP/MBP slope, and the theoretical value of the QKD for a systolic pressure of 100 mm Hg and a heart rate of 60 beats/min (QKD100-60) were calculated. The patients were then given antihypertensive treatment and followed by their family physicians, who were unaware of the QKD, AASI, and PP/MBP slope results. Regular updates on patients were obtained. The reproducibility of measurements was studied in 38 normal subjects evaluated on two occasions. RESULTS: The reproducibility of the AASI and the PP/MBP slope was less than that of BP over 24 h and of QKD100-60. The cohort comprised 469 patients. With an average follow-up of 70+/-39 months, 62 CV complications, including 13 deaths, were recorded. In the monovariate analysis, age, PP over 24 h, QKD100-60, AASI, and the PP/MBP slope were significantly related to the occurrence of complications. In the multivariate analysis, when age and PP over 24 were included in the model, only QKD100-60 remained significantly linked to CV events. CONCLUSIONS: Our data support the value of the AASI as an indirect estimate of AS and as an element in the evaluation of CV risk in hypertensive patients. However, the reproducibility of this index is less, and its predictive value for complications is poorer, than that of QKD100-60, a parameter that we believe is more closely linked to AS.

ECG detection of left ventricular hypertrophy: the simpler, the better?

OBJECTIVE: ECG is commonly employed to identify left ventricular hypertrophy (LVH) and a high risk of cardiovascular events (CVE) in hypertensive patients. However, the multiplicity of the existing criteria does not simplify interpretation of the data. We compared a number of common criteria in hypertensive patients by taking as references left ventricular mass (LVM) measured by echocardiography and prediction of incident CVE. METHODS: The population was a cohort of 958 hypertensive patients (mean age 48 years) recruited before any treatment and having benefited from an ECG and an echocardiography. We evaluated their outcomes at regular intervals. We examined the relationships between several ECG criteria of LVH and LVM as well the occurrence of CVE. RESULTS: Among the various parameters tested (Sokoloff, Cornell, Cornell product) the simple measurement of the RaVL wave offered the best correlations to LVM and the best prediction of the existence of an echocardiographic LVH (receiver-operating characteristic curves). Its alterations were best correlated with the changes in LVM during the follow-up period. Moreover, this simple measurement offered the best performance for the prediction of the occurrence of CVE (123 events after a mean lapse of 12 years). CONCLUSION: In the interpretation of an ECG in the hypertensive patient, the single measurement of the R wave in aVL gives results at least as good as those of more complicated indices, which do not appear to contribute further to the diagnosis of LVH and the prediction of cardiovascular risk.

Prognostic value of the extent of left ventricular hypertrophy and its evolution in the hypertensive patient.

OBJECTIVE: Left ventricular hypertrophy (LVH) is a marker of cardiovascular risk. However, the progression of the risk as a function of the course of the LVH has only been the subject of few studies. METHODS: We report the consequences of the evolution of the left ventricular mass (LVM) in a cohort of hypertensive patients whose LVM was measured before any antihypertensive treatment. RESULTS: We followed up for an average of 12 years, 763 hypertensives with LVM measurement by echocardiography on inclusion. In this population, 117 cardiovascular complications occurred and the initial LVM appeared to be the most powerful marker of risk. A cutoff of 51 g/m(2.7) for the LVM index (LVMI) offered the best compromise of sensitivity and specificity in the prediction of complications. A second determination of LVM was carried out in 436 patients on average 5 years after inclusion. In this sub-group, 82 complications were recorded after an average interval of 13 years. The 51 g/m(2.7) value of LVMI over the follow-up offered the same sensitivity (74%) and specificity (52%) in the prediction of complications. The progression of the LVM was related to the occurrence of complications independently of the basal value and other risk factors. CONCLUSIONS: We confirm LVMI as a powerful risk factor in hypertension with a cutoff of 51 g/m(2.7), which offers the same sensitivity and specificity whether the LVM was determined before or during treatment. The progression of LVM, on average 5 years after the initial measurement had a prognostic value independent of the initial determination.

Determination of central blood pressure by a noninvasive method (brachial BP and QKD interval).

BACKGROUND: The measurement of central blood pressure (BPc) has become a matter of importance. Several therapeutic trials have noted a different protective effect against cardiovascular complications with different antihypertensive strategies, but an identical decrease in brachial BP (BPb). A possible explanation lies in the different effects of the treatments on BPc. We propose a new noninvasive method for the automatic measurement of BPc based on the QKD interval, an arterial stiffness marker. MATERIALS AND METHODS: This study was carried out on patients referred for cardiac catheterization. We simultaneously measured the central SBP (SBPc) invasively with a pigtail probe, and the BPb by a cuff coupled with recording of the QKD interval. Two cohorts were studied, one to define an algorithm of SBPc estimation and one to validate this algorithm. RESULTS: The first cohort included 65 patients. We performed 136 simultaneous measurements. In the multivariate analysis, four variables were significantly correlated with SBPc: mean BPb (mBPb), QKD, height and heart rate (HR) with the following regression equation: SBP = 105 + 1.29 × mBPb - 0.39 × HR - 0.30 × height - 0.11 × QKD. This equation estimated 81% of the variance of the invasive SBPc ± 13 mmHg. This algorithm was then tested in another cohort of 80 patients. Difference between measured and estimated SBPc was 2 ± 14 mmHg. CONCLUSION: This study showed that it is possible to estimate SBPc by simultaneous measurement of QKD and BPb. If further studies confirm these results, a noninvasive ambulatory method of monitoring of SBPc could be employed in clinical practice.

Atrioventricular conduction in the hypertensive patient: influence of aging, pulse pressure, and arterial stiffness.

Atrioventricular (AV) conduction time (PR interval) lengthens with age. Hypertension is often presented as an accelerated aging of the heart and arteries. The principal marker of arterial aging is an increase in arterial stiffness and pulse pressure. We were interested to find out whether parameters of blood pressure and arterial stiffness were related to the PR interval and whether they influenced its long-term progression. We examined factors linked to the PR interval at baseline in a cohort of untreated hypertensive patients including office and 24-hr blood pressure and arterial stiffness (QKD(100-60)). Long-term evolution of the PR interval and related factors were obtained during follow-up of this population. Baseline data were obtained in 1,034 untreated hypertensive patients. At baseline, four variables emerged as significantly and independently correlated with PR interval: Gender, age, weight, and heart rate. During follow-up (137 ± 78 months), 328 of these patients were re-examined. In this group, PR increased from 159 ± 20 to 167 ± 25 msec (p<0.001), a mean alteration of 8 ± 19 msec. This change was correlated with the baseline 24 hr PP (r=0.17, p=0.004) and with the duration of follow-up (r=0.13, p=0.02). In the group with baseline evaluation of arterial stiffness (n=141), QKD(100-60) was correlated with the change in PR interval (r= -0.33, p<0.0001) along with the duration of follow-up (r=0.22, p=0.005). This study shows a link between baseline increased pulse pressure or arterial stiffness with the prolongation of the PR interval with aging. Because this link was observed during follow-up, it is possible that increased arterial stiffness favors the increase in the PR interval with age.

Impact of malignant arterial hypertension on the heart.

OBJECTIVES: To assess the consequences of malignant hypertension and its evolution with antihypertensive treatment. BACKGROUND: Malignant hypertension can be considered as a model of the effects of very high blood pressure and renin-angiotensin levels on target organs. However, the consequences on the heart have been little studied. METHODS: The consequences of malignant hypertension on left-ventricular function and its evolution with treatment were assessed with echocardiography in a prospective study between January 2004 and June 2009. RESULTS: During the study period, 46 patients were referred to our unit for malignant hypertension of whom 25 could be included in the echocardiographic study. These patients showed at baseline important left-ventricular hypertrophy and alteration in systolic function. Global longitudinal strain was the most sensitive tool to assess impaired systolic function and was significantly reduced in 13 patients (<12.8, 52%). Short-term follow-up (1-3 months) showed a rapid improvement in systolic function together with significant hypertrophy regression. With a follow-up of 11 months on average all patients had recovered a normal global longitudinal strain with further but incomplete regression of hypertrophy. CONCLUSIONS: Our study highlights the significant impact of malignant hypertension on systolic function of the left ventricle, and the ability of this ventricle to quickly recover normal systolic function under antihypertensive treatment.

Ambulatory or home measurement of blood pressure?

Ambulatory blood pressure monitoring (ABPM) and home blood pressure (HBPM) monitoring have been shown to be superior to conventional measurement of blood pressure in terms of reproducibility, relationship to the impact of high blood pressure on target organs, and the prediction of cardiovascular events. Nevertheless, these 2 techniques have yet to find their place in the diagnosis of hypertension and during evaluation of the efficacy of antihypertensive treatment. Although these 2 methods do not give identical results in approximately 20% of cases, their diagnostic performance and prognostic value are quite comparable. Although ABPM remains a valuable tool in clinical research, its utilization in routine clinical practice is limited by cost and availability. HBPM is increasingly employed for informed and well-managed patients, and it can help to improve control of the patient's blood pressure. Physicians involved in the management of hypertensive patients should be aware of its value in order to assist patients in their care.

Long-term influence of antihypertensive treatment on arterial stiffness assessed by ambulatory measurement of the QKD interval.

An increase in arterial stiffness is an important risk factor for cardiovascular events. However, there are few data on the long-term evolution of arterial stiffness in treated hypertensives. We evaluated the progression of arterial stiffness in 120 initially untreated hypertensive patients whose arterial stiffness was assessed by the ambulatory monitoring of the QKD interval measured at baseline and then more than 1 year later. The ambulatory method produced an isobaric index of arterial stiffness, the QKD(100-60). Out of these patients, 30 with white coat hypertension did not receive any treatment, and over a mean follow-up period of 5 years their QKD(100-60) was unchanged. The 90 other patients received antihypertensive treatment (average of 2.5 classes of drug) over a mean period of 6 years. In this population, the mean 24 h blood pressure (BP) was significantly reduced (-9 mm Hg for systolic BP, -6 mm Hg for diastolic BP) and the QKD(100-60) was prolonged (+3.5 ms, P<0.05). The presence of type 2 diabetes in 17 of these patients was the sole factor negatively correlated with the improvement in QKD(100-60). An initial reduction in QKD(100-60) appeared to be a factor of resistance to the BP-lowering action of the medication. Antihypertensive treatment has a long-term action on arterial stiffness. The existence of diabetes appeared to have a negative influence on this improvement. Furthermore, an increase in arterial stiffness may be a factor of resistance to the action of antihypertensive medication.

Long-term decline in renal function is linked to initial pulse pressure in the essential hypertensive.

OBJECTIVES: In the absence of malignant hypertension, the mechanisms for the decline in renal function in hypertensive patients are not well known. Several recent studies, essentially cross-sectional, point to a role for an increase in arterial stiffness and its corollary, the increased pulse pressure (PP), in barotrauma of the renal glomerulus. METHODS: We examined relations between the PP measured on consultation or by 24-h ambulatory blood pressure monitoring and the long-term decline in renal function in a population of essential hypertensive patients initially untreated, with normal renal function and without proteinuria. We evaluated the renal outcome of 375 patients of mean age 49 years in a baseline state over a mean follow-up period of 14 years. RESULTS: At follow up, the glomerular filtration rate estimated from the modification of diet in renal disease formula was below 60 ml/min per 1.73 m2 in 51 of these patients, two of whom required dialysis. The blood pressure parameter best correlated with subsequent renal failure, independently of other factors of risk such as age or type 2 diabetes, was the PP measured either in consultation or by ambulatory blood pressure monitoring before starting treatment. CONCLUSION: The PP either measured on consultation or by ambulatory monitoring emerged as an independent determinant of the decline in renal functions in this population, pointing to the possibility of barotrauma of the glomeruli from increased arterial stiffness.

Acoustic videodensitometric parameters correlate with abnormalities of left ventricular filling in hypertensive patients assessed via Doppler Tissue Imaging.

PURPOSE: Using a videodensitometric technique developed in our center we investigated whether the amplitude of variation of gray levels in the interventricular septum was related to functional parameters, especially ventricular filling as studied by doppler tissue imaging (DTI) in hypertensive patients. METHODS AND RESULTS: We included 35 hypertensive patients from whom we recorded a two dimensional sequence of the left ventricle from the short axis parasternal view and a doppler tissue scan of the mitral ring. Two-dimensional sections were then analyzed with Iodp software to measure variations in levels of gray in the septum. We observed significant correlations between these variations and the velocity of the Ea wave on DTI of the lateral wall (r = 0.49, p < 0.002). On dividing this population into three sub-groups according to the Appleton classification of ventricular filling, we noted a tendency to a reduction in amplitude of variations of gray of the septum in cases with abnormalities of relaxation. This was even more marked in cases with a restrictive or pseudo-normal profile. CONCLUSION: These observations point to the interest of sonographic videodensitometry in the evaluation of hypertensive cardiopathy. Further studies will be required to determine whether it can define the extent of the abnormalities of myocardial structure and the degree of fibrosis.