NOVACOR ACCUEIL APPLICATIONS CLINIQUES ARTERIAL COMPLIANCE - QKd 100-60



Arterial Compliance - QKd 100-60


CLINICAL CONTEXT

Large arteries damage is a major contributor to cardiovascular diseases. Therefore, the focus in preventing and treating cardiovascular disease (CVD) today is moving from a statistical risk factors approach (age, BP level, cholesterol, diabete, …) toward direct assessment of arterial wall impairment (arterial thickness, arterial wall properties). The arterial wall elasticity is a major function of the aorta and large arteries that aims to damp down the systolic wave pressure in order to create a continuous blood flow. Loss of elasticity (increased arterial rigidity) leads to pulse pressure rise, which has been shown to be an independent cardiovascular risk factor in elderly.

Pulse Wave Velocity (PWV) is a non-invasive and simple method used as an index of large artery elasticity and stiffness. However, PWV measurement is modulated by blood pressure level at the time of the measurement (thus sensitive to the "white-coat" effect) and is operator-dependent.

The QKd is an alternate method to measure PWV during an ABP monitoring in the auscultatory mode. The QKd interval is the time interval between the onset of the QRS on the electrocardiogram (Q) and the last Korotkoff sound (K) corresponding to the diastolic pressure (d). It allows to automatically derive the QKd100-60 index which is totally independent of the BP level, fully reproducible and insensitive to the "white-coat" effect (ambulatory recording).

The clinical validation and the pronostic value of the QKd100-60 index have been established by several clinical studies.

QKd100-60 index is a parameter available with all Novacor ambulatory blood pressure monitors featuring Ausculatory mode.



QKd MEASUREMENT BASICS WITH THE DIASYS INTEGRA II OPERATING IN THE ECG-GATED AUSCULTATORY MODE

1 – QRS complexes are detected with the ECG cable placed on the chest.

2 – Korotkoff sounds are picked up with the microphone located in the cuff on the brachial artery.

3 – QKd is calculated by the recorder for each BP measurement.

4 - QKd100-60 index, theoretical QKd100-60 and %QKd100-60 are processed automatically by DiasySoft or HolterSoft Ultima software.




NOVACOR'S SCIENTIFIC PUBLICATIONS

Arterial stiffness predicts severe progression in systemic sclerosis: the ERAMS study


Prognostic value of QKd interval corrected by QRS duration in hypertensive patients


Arterial stiffness evaluated by measurement of the QKd interval is an independent predictor of cardiovascular events


Beyond blood pressure measurements: monitoring of the appearance time of Korotkoff sounds


Assessment of Arterial Distensibility by Monitoring the Timing of Korotkoff Sounds


Relationship between arterial distensibility and left ventricular function in the timing of Korotkoff sounds (QKd interval) . An ambulatory pressure monitoring and echocardiographic study


Pronostic value of ambulatory monitoring of QKd interval to assess arterial stiffness in hypertensive patient


Prognostic Value of Ambulatory Measurement of the Timing of Korotkoff Sounds in Elderly Hypertensives, a Pilot study


Alteration of arterial distensibility in systemic sclerosis


Assessment of arterial distensibility in hemodialyszed patients. Is it related to secondary hyperparathyroidism (HPT)?


Changes on arterial distensibility induced by hormonal replacement therapy in both hypertensive and normotensive post-menopausal women: non-invasive ambulatory assessment


Effect of age on vascular compliance in man: which are the appropriate measures?


Ambulatory Measurement of the Timing of Korotkoff Sounds in a Group of Normal Subjects

Determinants of arterial compliance in patients treated by hemodialysis

Evolution of ambulatory measurement of blood pressure and parameters of arterial stiffness over a 1-year period in patients with systemic sclerosis: ERAMS study

Reduction in Arterial Distensibility in Hypertensive Patients as Evaluated by Ambulatory Measurement of the QKD Interval Is Correlated With Concentric Remodeling of the Left Ventricle


ARTERIAL STIFFNESS PREDICTS SEVERE PROGRESSION IN SYSTEMIC SCLEROSIS: THE ERAM STUDY


Joël Constans(a), Christine Germain(b), Philippe Gossec(c), Jacques Taillard(a), Kiet Tiev(d), Isabelle Delevaux(e), Luc Mouthon(f), Claude Schmidt(g), Florence Granel(h), Pascale Soria(i), François Lifermann(j), Gabriel Etienne(k), Fabrice Bonnet(l), Karim Zoulim(m), Dominique Farge-Bancel(n), Isabelle Marie(o), Yannick Allanore(p), Jean Cabane(d), Alain Amonchot(q), Isabelle Macquin-Mavier(r),
Marianne Saves(b), Faiez Zannad(s) and Claude Conri(a), the ERAMS investigators
.

Objective
The ERAMS study addressed the value of arterial stiffness in predicting the severity of systemic sclerosis.

Methods
ERAMS was a prospective multicentre cohort study including patients with definite systemic sclerosis.
Arterial stiffness was measured by the standardized noninvasive QKd 100-60 method. Clinical evaluation, biological measurements, functional respiratory tests and cardiac Doppler echography were performed at inclusion then each year until 3 years’ follow-up was completed. Progression was defined as mild (articulations, muscle, oesophagus or skin involvement) or severe (lung, heart or kidney involvement) by a critical event committee. The prediction of severe progression was studied for QKd 100-60 as well as clinical and biological data at baseline by univariate and multivariate analysis.

Results
Ninety-nine patients were included (81 women, 18 men, mean age 57 years, standard deviation 12.5). Although their blood pressure profile was normal, half the patients had increased arterial stiffness (QKd 100-60<200 ms). There was a significant relationship between age-adjusted arterial stiffness and decrease in carbon dioxide diffusion (P<0.03) or haemoglobin rate (P<0.01). By univariate analysis, severe progression after 3 years was predicted by age (PU0.04), lung involvement (PU0.04), diffusion of lung carbon oxide (DLCO) (P<0.01), skin score (PU0.02), haemoglobin (P<0.01) and baseline Qkd 100-60 divided into two classes according to the median (P<0.01). By multivariate analysis, only haemoglobin rate [odds ratio (OR) 0.4, 95% confidence interval (CI) 0.2–0.9] and QKd 100-60 (OR 19.6, 95% CI 1.2–308.2) predicted severe progression of systemic sclerosis.

Conclusion
The measurement of arterial stiffness by the QKd method is a useful objective method for assessing the
prognosis of systemic sclerosis independently from other data. J Hypertens 25:1900–1906
2007 Lippincott Williams& Wilkins.

Journal of Hypertension 2007, 25:1900–1906

Keywords
arterial stiffness, prognosis factors, systemic sclerosis, vascular disease

(a)Vascular and Internal Medicine Unit, CHU Bordeaux, (b)Clinical Epidemiology Unit, CHU Bordeaux, (c)Cardiology and Hypertension Unit, CHU Bordeaux, (d)Internal Medicine Unit, CHU Saint-Antoine, Paris, (e)Internal Medicine Unit, CHU Clermont-Ferrand, (f)Internal Medicine Unit, CHU Cochin, Paris, (g)Vascular Medicine Unit, CHU Nancy, (h)Dermatology Unit, CHU Nancy, (i)Internal Medicine Unit, CHU Limoges, (j)Internal Medicine Unit, CHG Dax, (k)Internal Medicine and Tropical Diseases Unit, CHU Bordeaux, (l)Internal Medicine and Infectious Diseases Unit, CHU Bordeaux, (m)Internal Medicine Unit, CHU Caen, (n)Internal Medicine Unit, CHU Saint-Louis, Paris, (o)Internal Medicine Unit, CHU Rouen, (p)Rheumatology Unit, CHU Cochin, Paris, (q)Cardiology Unit, CHU Clermont-Ferrand, (r)Clinical Investigation Unit, CHU Henri Mondor, Créteil and (s)Clinical Investigation Unit, CHU Nancy, France

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PROGNOSTIC VALUE OF QKD INTERVAL CORRECTED BY QRS DURATION IN HYPERTENSIVE PATIENTS


P. Gosse(1), R. Lasserre(1), C. Minifie(1), P. Lemetayer(1)

(1) Hopital Saint André, Bordeaux, France

Objectives
The QKD interval is measured between the onset of QRS on the ECG and detection of last Korotkoff sound by a microphone placed on the brachial artery while measuring BP. It is the sum of pre ejection time(PE) and pulse transmission time(PT) and is correlated to PWV. This interval is automatically monitored with BP and HR every 15' during 24h with an ABPM device (Diasys integra, Novacor, France). The 96 measurements obtained allow to automatically calculate the QKD 100-60, QKD value for 100 mmHg SBP and 60 bpm HR. This indices of arterial stiffness has been shown to be linked to future cardiovascular (CV)events, independently of 24h BP. However this interval may be abnormally prolonged in case of left bundle branch blocks (LBBB).

Methods
We tested the effects of simply removing QRS duration from QKD 100-60 value on the prediction of CV events in a population of 412 hypertensives (247 males, age = 53±14 years, office BP = 158±19/97±11 mmHg, 24h BP = 133±17/86±11 mmHg) followed prospectively.

Logo Diasys 2

Results
Mean follow up was 65 months, 32 pts were lost, 49 CV events occurred including 11 deaths. Cox model showed that baseline QKD 100-60 (m = 202±19, 142-254 msec) was significantly (p < 0.05) associated to events independently of age, 24h SBP and other traditional risk factors. Removing QRS duration (m = 85±10, 61-158 msec) improves the relation to events (monovariate c 2 = 38 versus 30).

Conclusion
Removing QRS duration from QKD 100-60 improves its predictive value of future CV events and allow to use this method in pts with LBBB.

Abstract: P3.255
Citation: Journal of Hypertension Volume 23, Supplement 2, June 2005, page S347

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Arterial stiffness evaluated by measurement of the QKd interval is an independent predictor of cardiovascular events


Philippe GOSSE, MD; Raphael LASSERRE, MD; Catherine MINIFIE, MD; Philippe LEMETAYER, MD; Jacques CLEMENTY, MD

Background
The QKD interval is the time between the QRS wave on the ECG and detection of the last Korotkoff sound during blood pressure measurement. Measurement of the QKD interval during ambulatory blood pressure monitoring provides an automatic evaluation of arterial stiffness. The objective of this longitudinal study was to examine the relationship between arterial stiffness assessed by this method and the occurrence of cardiovascular complications in a cohort of initially untreated hypertensive patients.

Methods
The initially untreated hypertensive patients were included in the cohort of hypertensives recruited in our center between January 1992 and December 1999. They all benefited from ambulatory measurement of the OKD interval and blood pressure over 24 hours. Most of these patients were given antihypertensive treatment and were followed up by their family physicians unaware of QKD results. Their outcome was evaluated in 2003 by inquiry from the patients themselves or their family physicians.

Results
The initial population comprised 412 patients. At the end point. 33 had been lost to follow up.. We recorded 49 cardiovascular events in this population with an average follow up of 65±36 months. In a Cox model, the arterial stiffness assessed by the QKDIOO-60 as a percentage of the height predicted normal value was significantly associated with the occurrence of cardiovascular complications independently of age and mean 24-hour blood pressure.

Conclusions
This study employing ambulatory measurement of the QKD interval showed that an increase in arterial stiffness was a marker of cardiovascular risk. We show for the first time that its value persists after taking account of the mean systolic pressure over 24 h.

Keywords: Arterial stiffness, QKD interval, ambulatory measurement of blood pressure, cardiovascular complications, hypertension

American Journal of Hypertension, AJH 2005;18:470-476

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Beyond blood pressure measurements: monitoring of the appearance time of Korotkoff sounds


Philippe Gosse, Corinne Braunstein and Jacques Clementy

We have recently proposed a new method to evaluate the physical properties of arteries based on measurement of the QKD interval together with blood pressure arid heart rate with an ambulatory blood pressure monitoring device. This interval is the time
between the onset of the depolarization (ORS) on the electrocardiogram (Q) and detection of the last Korotkoff (K) sound at the level of brachial artery during cuff deflation, corresponding to diastolic blood pressure (D). The QKD interval is the sum of the pre-ejection period and of the pulse transmission time from the aortic valves and the microphone. Thus, it is linked to the pulse wave velocity on an arterial segment which includes the ascending aorta and a portion of the subclavian and brachial arteries. From each 24 h monitoring, the average 24 h OKD, the slope of variation of QKD against blood pressure and a normalized QKD
(QKD 100-60) for systolic blood pressure of 100 mmHg and heart rate of 60 beats/mm are calculated. Stiffer arteries as observed with ageing or hypertension are characterized by the reduction of these three parameters. The reproducibility of this method is good. In a pilot study of elderly hypertensive patients we have shown that QKD1.60 has a strong and independent predictive value for future cardiovascular events. Therefore, this method may add significant information to ambulatory blood pressure monitoring.

Key words: ambulatory blood pressure monitoring, arterial distensibility
Blood pressure monitoring 1, p. 193-195, 1996

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Assessment of Arterial Distensibility by Monitoring the Timing of Korotkoff Sounds


Philippe Gosse, Pascal Guillo, Gilles Ascher, and Jacques Clementy

The timing of Korotkoff sounds, blood pressure, and heart rate can now be monitored in the ambulatory patient the QKD interval is the time between the onset of the depolarization on the electrodiogram (Q) and detection of the last Korotkoff sound (K) at the level of brachial artery during cuff deflation, corresponding to diastolic blood pressure (D). Because this interval is inversely related to pulse wave velocity, this recently developed device enables evaluation of the influence of blood pressure on arterial rigidity, providing valuable information on the properties of the arteries. In this study, we examined the influence of hypertension and age on the above parameters and their correlations to left ventricular mass.

QKD interval, blood pressure, and heart rate were monitored over a period of 24 h (four measurements/hour) in 33 normotensive and 70 untreated essential hypertensive patients. The slopes of the plots of QKD interval versus systolic and pulse pressure during the 24 h were calculated for each patient. The influence of age and hypertension on these slopes was tested by comparison of matched groups and multivariate analysis. Moreover the relationships between these parameters and echocardiographically assessed left ventricular mass were studied in 37 patients. We found a reduction in mean QKD interval with age and hypertension, reflecting the recognized higher pulse wave velocity in these patients. The slopes of the plots of QKD interval versus blood pressure were also lower in these patients, indicating the smaller influence of a change in blood pressure on pulse wave velocity in patients with stiffer arteries. Both average 24-h systolic blood pressure and the slope of QKD interval versus pulse pressure were significantly and independently correlated to left ventricular mass index. The influence of blood pressure on arterial rigidity can be evaluated by this new monitoring device. Our results showed that pulse wave velocity was less affected by a change in blood pressure in the patients with the stiffer arteries.

Key words : Pulse wave velocity, arterial distensibility, hypertension, ambulatory blood pressure monitoring, Korotkoff sounds. American Journal of Hypertension 7, p.228-233, 1994
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Relationship between arterial distensibility and left ventricular function in the timing of Korotkoff sounds (QKd interval) . An ambulatory pressure monitoring and echocardiographic study


Philippe Abassade, Yves Baudouy. Cardiology.

Timing of Korotkoff sounds (QKd) is the time interval between Q wave ECG and pressure diastolic sound, determined by a routine ambulatory pressure monitoring (AMP) (Diasys Integra, Novacor). It is known to be an arterial distensibility index. However, this interval time includes pre-ejection time (PET) which is related to left ventricular (LV) function.

The aim of the study is to define the relative influences of LV function and arterial distensibility in QKd interval.

Sixty consecutive patients, with or without cardiac disease, out or in-hospital, were included. Patients with left bundle branch block, pace maker, or atrial fibrillation were excluded. The echocardiography-Doppler (ED) study collected LV function index : Shortening Fraction (SF), Ejection Fraction (EF), stroke index (SI), (PET), ejection time (ET). Pulse Wave velocity (PWV) was determined by ED in two points of the descending thoracic aorta. The AMP study collected-usual-pressure data : systolic (Ps), diastolic, mean (Pm), pulse pressure (Pp), simultaneously with PWV and over 24h. An automatic assessment of the QKd interval simultaneously with PWV was performed by the monitoring device. Another arterial distensibility index was calculated from ED and AMP:
Burton index as SI / Pp. Values are mean plusminus SD, relationships between various parameters were fitted by a linear function.

QKd is correlated with PWV (n = 53 , p = 0.007, r = 0.37), with Burton index (n = 50 , p = 0,001,
r = 0.47).

QKd is correlated with CV function index like FE (n = 55, p < 0,001, r = 0,66), Ps/systolic diameter
(n = 54, p < 0.001 , r = 0.75 ), SF/ET (n = 35, p = 0.001, r = 0.55), ET/PET (n = 35, p <0.001, r 0.60).

No correlation was found between QKd and EF when PET are withdrawn from QKd (n = 35, p = 0.21,
r = 0,22).

QKd interval is a composite index which reflects not only arterial distensibility but also LV function.

Key words : Arterial distensibility, left ventricular function, echocardiography.

American Journal of Hypertension 15:4, p.67A, 2002

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PROGNOSTIC VALUE OF AMBULATORY MONITORING OF QKD INTERVAL TO ASSESS ARTERIAL STIFFNESS IN HYPERTENSIVE PATIENT


Philippe Gosse*, Raphael Lasserre*, Catherine Minifié*, Philippe Lemetayer*, Jacques Clementy*
*Hôpital Saint André, Bordeaux, France

Objective
The prognostic value of pulse wave velocity (PWV) was demonstrated in pts with hypertension or renal failure. Another method, the monitoring of QKD interval (inversely correlated to PWV) offer the advantages of being automatic and associated to 24h BP monitoring. Its prognostic value was assessed in hypertensives.

Design and methods
ABPM with a device allowing to monitor the QKD interval allow to assess both 24h BP and the QKD100-60 (value of QKD for 100 mmHg systolic BP and 60 bpm HR). As QKD is linked to the pulse transmission time, QKD100-60 has to be corrected for height and is presented as the percentage of the height predicted value in normal subjects (QKDh). All these parameters are automatically calculated by the software without observer bias. Its prognostic value was assessed in a cohort of previously untreated hypertensives who underwent 24h BP monitoring with QKD interval at inclusion (Diasys from Novacor, Rueil Malmaison, France, 4 measures/h) and were prospectively followed up after antihypertensive treatment was started.

Results
We included 360 pts (222 males,aged=53±14 years, Office BP=158±20/98±11mmHg, 24hBP=133±17/86±11 mmHg, QKD100-60 = 202±19 msec, QKDh=95±9%). During follow up (average=57±31 months) 40 patients were lost (not significantly different from the whole group), 39 cardiovascular events occurred . The population was split into quartiles of baseline QKDh . The outcome was significantly worse (p<0.001) with decreasing QKDh (Fig). Cox model showed a significant relation (p<0.05) between QKDh and events independently of age and 24h average systolic BP. Relative risk for QKDh <95%, adjusted for age and 24hSBP was 4.

Conclusion
Arterial stiffness as assessed from QKD monitoring during 24h is associated with increased cardiovascular risk independently of age and 24h systolic BP.*

Journal of Hypertension, volume 21 (Suppl. 41), June 2003, page S245, abstract P3.67

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Prognostic Value of Ambulatory Measurement of the Timing of Korotkoff Sounds in Elderly Hypertensives, a Pilot Study
 
Philippe Gosse, Philippe Gasparoux, Pascal Ansoborlo, Philippe Lemetayer
and Jacques Clementy

Alteration in the physical properties of the large arteries is probably an important contributory factor in morbidity and mortality in the elderly as well as in patients with hypertension or diabetes. We have developed a simple method based on the ambulatory measurement of the timing of Korotkoff sounds (QKD interval), together with blood pressure, to assess these properties. We report its prognostic value in a retrospective survey of elderly hypertensives. We included in this study 134 hypertensive patients over 45 years of age with no cardiovascular complications, either receiving placebo or prior to treatment with antihypertensive medication and seen between January 1992 and July 1993. In June 1995, a survey was carried out to determine outcome by contacting the patients themselves and their family physicians. Data on outcome were obtained for 111 patients with a mean follow-up period of 30 +/- 8 months. At least one cardiovascular complication was recorded during the follow-up period in 14 patients. From the Cox model, data obtained from QKD monitoring, namely the QKD 100-60, was the best predictor of complications and remained significant (P<.01) even after introduction of age, mean 24h SBP, gender, and smoking into the model. A QKD 100-60 below 187 msec was accompanied by a relative hazard of cardiovascular complications adjusted for age and mean 24 h BP of 7.3 (95% confidence interval : 2.9 to 11.7). The indices provided by the ambulatory measurement of QKD interval are significant predictors of cardiovascular complications independently of age and BP. This new method seems to add useful information to classic ambulatory blood pressure monitoring. However this will require confirmation in a large prospective study.
Am J. Hypertens 1997; 10:552-557
Copyrights 1997 American Journal of Hypertension, Ltd.
Keywords : Korotkoff sounds, arterial distensibility, ambulatory blood pressure monitoring, QKD interval, hypertension, prognostic tests.

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Alteration of arterial distensibility in systemic sclerosis

J.Constans, P.Gosse, JL Pellegrin, P.Ansoborlo, B.Leng, J.Clémenty and C.Conri
Abstract: Constans J., Gosse P., Pellegrin JL, Ansoborlo P, Leng B., Clémenty J., Conri C. (Hôpital Saint-André. Bordeaux : and Hôpital Haut-Lévêque. Pessac : France). Alteration of arterial distensibility in systemic sclerosis.
J.Intern. Med. 1997 : 241 : 115-18.
Objectives: To evaluate the distensibility of large arteries in patients with systemic sclerosis (SSc).
Design: Prospective case-control study including unselected patient with SSc.
Setting: One cardiology and two internal medicine units in a teaching hospital.
Subjects: Eighteen patients with SSc and controls matched for age, sex, height, weight and 24-h ambulatory blood pressure (BP).
Intervention: The timing of Korotkoff's sounds (QKD interval), a newly described noninvasive ambulatory method was used to measure arterial distensibility during 24 h.
Main outcome measures: Two endpoints were used : QKD 100-60 (normalized for a heart rate of 60 beats min-1 and a systolic BP of 100 mmHg) and the slope of QKD against pulse pressure.
Results: The patients with SSc had a lower slope of QKD against pulse pressure than the controls (median 0.55, range 0-1.21, versus 0.92, range 0.5-1.34, respectively : P = 0.003) and a lower QKD 100-60 (medians/ranges respectively 191 (162-216) and 203 (169-231) : P = 0.01).
Conclusions: These results indicate that arterial distensibility of large arteries is decreased in SSc.
Keywords: Systemic sclerosis, arterial distensibility.

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Assesment of arterial distensibility in hemodialyzed patients. Is it related to secondary hyperparathyroidism (HPT)?

C. Lasseur, C. Level, Ph Gosse, D. Hachem and C. Combe
Dept of Nephrology and Cardiology, Hôpital St André, Bordeaux, France

Cardiovascular disease (CD) is the major cause of mortality in haemodialyzed patients (HD pts). In the general population (GP), alterations in the physical properties of large arteries have an impact on mortality and morbidity in CD. In HD pts, structural arterial properties may be influenced by numerous mechanical and/or humoral factors and contribute to cardiovascular morbidity and mortality. Arterial distensibility is assessed during a 24 hrs monitoring of arterial blood pressure, by the measure of the QKd interval, i.e. the time between the onset of the depolarisation on the ECG (Q) and detection of the last Korotkoff sound (K) at the level of the brachial artery during cuff deflation, corresponding to diastolic blood pressure (d). Previous work has demonstrated a correlation between reduced QKd interval and reduced arterial distensibility.
We have investigated 24 HD pts (M: 17, F: 7), mean age 65 yrs (17-86) with a mean time of dialysis of 3.25 ± 4.3 yrs (0.5 - 20.6). QKd, echocardiography (ECHO) parameters and various clinical and biochemical parameters of potential influence on arterial distensibility were evaluated. In these non-hypertensive HD pts (MAP 92 ± 14 mmHg), QKd was lower than the theoretical QKd defined in a non-hypertensive GP (195 ± 26 vs 210 ± 7 ms, p <0.001), indicating low arterial distensibility. Despite normal BP, left ventricular mass was increased (150 ± 62 g/m), but there was no correlation between ECHO parameters and QKd, in variance with previous findings in GP. By multivariate analysis, QKd was not correlated to age, HD duration, interdialytic weight gain, MAP, phosphorus and levels, but it was correlated to ionised calcium (iCa, r = 0.60, p < 0.004).
Arterial distensibility is lower in HD pts than in GP. Moreover, in this population, it is not influenced by factors related to dialysis. The positive correlation between iCa and QKd suggest that other parameters related to calcium and phosphorus metabolism might contribute to the alterations in the physical properties of large arteries in HD pts.

AJHI994I7: 228-233

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Changes on arterial distensibility induced by hormonal replacement therapy in both hypertensive and normotensive post-menopausal women: non-invasive ambulatory assessment

A.Calderon, JL Palma-Gamiz, V.Barrios
Service of Cardiology Heart & Hypertension Unit. Ramon y Cajal Hospital
Madrid (Spain)

Several studies indicate an improvement on cardiovascular risk profile in postmenopausal women treated with hormonal replacement therapy (HRT). Pulse wave velocity (PWV) based on QKD algorythm, is a validated method to assess indirectly physical properties of great arteries. To evaluate HRT on arterial distensibility changes, we have studied 51 postmenopausal women (group A) aged 41-60 yrs and 21 premenopausal women (group B) aged 45-50 yrs. In each case a 24-hour ambulatory blood pressure monitoring (ABPM) was performed, implemented with QKD algorythm to evaluate PWV expressed in msec. A 180 msec QKD value established the cut-off point for PWV normalcy. The following parameters were evaluated : age, postmenopausal evolution, mean systolic and diastolic 24-hour blood pressure, mean 24-hour QKD value (mQKD), and percentage of QKD>180 msec during ABPM. A 46,4% of women in group A was on HRT. A 28,6% of women in group A, showed also criteria for arterial hypertension, while in group B was 19,5% (p<0.05). Women in group A without HRT showed a mQKD of 176 msec, while in group B was 186 msec (p<0.05). Comparing all women included in group A, those on HRT showed a mQKD of 198 msec, in contrast with 184 msec in those women without HRT (p=0.039). Postmenopausal women on HRT taken all together, showed a mean 24-hour blood pressure of 95/73 mmHg, while those without HRT, this value was 97/74 mmHg (p=NS). Considering only hypertensive women on HRT in group A, mQKD was 209 msec, while was 187 msec for those hypertensive postmenopausal women without HRT (p<0.01). In conclusion : HRT improves physical properties (distensibility and compliance) of great arteries in both normotensive and hypertensive postmenopausal women expressed by increased QKD value. PWV in postmenopausal women is not directly related to blood pressure values. Further interventional studies are needed to demonstrate this beneficial effect.
Keywords: Hypertension, Hormonal Replacement therapy, arterial distensibility, pulse wave velocity, QKD.
May 1998

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Effect of age on vascular compliance in man: which are the appropriate measures?


C. Rajkumar, J.D. Cameron, J.S. Joshi, D. Lyons, P. Nihoyannopoulos, C.J. Bulpitt.
Section of Geriatric, Medicine Imperial College School of Medicine.
Hammersmith Hospital, London, England, UK

Introduction
Arterial compliance declines with aging and its measurement may help quantify a major aspect of aging process. Of the different measures available those most closely related to chronological age need to be identified. These may help to estimate biological age.

Design and Methods
Thirty six volunteers mean age 49 years (range 20-84 years), were recruited. Pulse wave velocity (PWV) was measured as the Carotid-finger interval, Carotid-toe interval and QKD interval (time between the Q wave and the arrival of the diastolic Korotkoff sound (K) over the brachial artery in diastoly (D). Central Aortic Compliance (CAC) was measured using applanation tonometry on carotid artery and simultaneous recording of aortic flow using Doppler recording over the suprastemal notch. Compliance was also calculated from stroke volume divided by pulse pressure (SV/PP).

Results
CAC, QKD interval and Carotid-toe interval correlated most closely to age, (r = -0.51, p < 0.05, -0.60, p < 0.01, -0.58 p < 0.001, respectively). The results after adjustment for blood pressure are also given by the regressions in the table below.

  Intercept
unadjusted
Slope
unadjusted
Slope
adjusted for SBP
Slope
adjusted for DBP
%Decrease
40-55 years
Carotid toe interval 220 -0.518** -0.660** -0.594* 3.9
QKd Interval 223 -0.783* -0.521 -0.780* 6.1
CAC -95 -0.032* -0.028 0.033* 13.0


  * p<0.05
** p<0.01
SBP=systolic blood pressure
DBP=diastolic blood pressure

The carotid-finger interval was only weekly and positively related to age, r = +0.19 (p = ns). This measure was, however, closely related to diastolic blood pressure, b = +0.83, p = 0.01.

Conclusions
1) Measurements of CAC, QKD interval and carotid-toe interval may be employed to assess the impact of age on vascular compliance.
2) Measures of peripheral compliance such as carotid-finger interval has to be employed to assess the relationship between peripheral vascular compliance and blood pressure.

Journal of Hypertension 1999, vol 17 (suppl 13)

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Ambulatory Measurement of the Timing of Korotkoff Sounds in a Group of Normal Subjects


Influence of Age and Height

Philippe Gosse, Véronique Jullien, Philippe Lemetayer, Philippe Jarnier and Jacques Clementy.
Saint André Hospital, Bordeaux, France.

Ambulatory measurement of timing of Korotkoff sounds (QKd interval) gives an estimate of arterial distensibility derived from the velocity of the pulse wave over a vascular territory that includes the ascending aorta. The main advantages of the method are that it is entirely automatic, non-operator-dependent, and highly reproducible, and produces a measure independent of instantaneous blood pressure. This study of a group of 180 normal subjects aged between 10 and 78 years was designed to produce references values and to study the influence of height. The results confirmed the reduction with age of arterial distensibility in the whole population. However before the age of 30, QKd 100-60 was positively correlated with height according to the relationship QKd 100-60 = 0.73 height (cm) + 91, but not with age. This equation enables calculation of the theoretical value of QKd 100-60 as a function of height for any patient to which the observed value can be expressed as a percentage. This effectively eliminates the influence of height, which reflects the lenght of the arterial segment under investigation.

Key words: Arterial distensibility, QKd interval, Korotkoff sounds, ambulatory blood pressure measurement.

Am J Hypertens 1999; 12:231-235 1999 Amercian Journal of Hypertension, Ltd.

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Determinants of arterial compliance in patients treated by hemodialysis


C. Level, C. Lasseur, Y. Delmas, M.C. Cazin, B. Vendrely, P. Chauveau, P. Gosse and C. Combe
Service de Néphrologie et Hémodialyse and Service de Cardiologie
Saint André Hospital, Bordeaux, France.

Abstract

Background
Cardiovascular disease is the principal cause of morbidity and mortality among hemodialysis patients. Several studies have demonstrated the importance of a reduction in arterial compliance in the development of cardiovascular complications, reflecting the interaction of functionnal and structural alterations of the peripheral arterial system and left ventriele. The aim of the present study was to demonstrate that arterial compliance, evaluated by automated recording of the QKd interval, was lower in hemodialysis patients than in normal subjects. A secondary objective of the study was to assess the influence of several factors, including calcium-phosphorus parameters, on decreased arterial compliance in these patients.

Patients and methods
Arterial compliance was evaluated in 24 chronic hemodialysis patients who had normal (n=12) or high blood pressure (n=12), using a method of measuring systolic wave velocity by automated recording of the QKd interval. This interval corresponds to the time (in ms) between the onset of the electrocardiogram QRS complex (Q) and the Korotkoff (K) sound at diastolic pressure (d) heard over the brachial artery during blood pressure measurement. The analysis was performed in comparison with reference values obtained in a population with normal renal function. The other parameters determined were : age, duration of chronic renal failure, duration of hemodialysis therapy, left ventricular mass, vascular calcification score, serum total and ionized calcium, phosphorus, parathyroid hormone, calcidiol, calcitriol, and blood concentration of hemoglobin.

Results
The arterial shiffness of all the patients was increased significantly (p<0.001) compared to reference values obtained from subjects without renal failure, the average age, height, and blood pressure of whom were similar to those of the patients. Multivariate analysis demonstrated a positive relationship among the QKd interval, serum total calcium, and the duration of hemodialysis. This suggested that arterial wall elastic properties were dependent not only on hypertension and constraints of pressure, but that they were also influenced by calcium and phosphorus metabolism and the duration of renal substituion therapy.

Conclusions
Arterial compliance, evaluated by the ambulatory method of QKd measurement, is reduced in chronic hemodialysis patients, and is inversely correlated with serum calcium concentration and dependent on the previous duration of hemodialysis therapy.

Key words: Arterial compliance, chronic renal failure, hemodialysis, arteriosclerosis, QKd interval.

Clinical Nephrology, Vol 56, N° 6/2001 (435-444)

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Evolution of ambulatory measurement of blood pressure and parameters of arterial stiffness over a 1-year period in patients with systemic sclerosis: ERAMS study


P. Gosse, J. Taillard, J. Constans on behalf of the ERAMS study investigators
Service de Cardiologie et Hypertension Artérielle et Service de Médecine Interne et Pathologie Vasculaire,
Hôpital Saint-André, 1 rue Jean Burguet, 33075 Bordeaux, France

Patients with systemic sclerosis commonly exhibit increased arterial stiffness, which may be predictive of the overall severity of the disease. The aim of the present study was to check the stability of parameters of arterial stiffness after 1 year in this population. ERAMS is a French multicentric prospective study designed to identify a link between arterial distensibility and outcome in 100 patients with systemic sclerosis. Arterial distensibility was evaluated by 24-h ambulatory monitoring of QKD interval along with blood pressure (BP) and heart rate (HR) (four measurements/hour). The index QKD100-60, which is linked to aortic distensibility, was calculated automatically. QKD100-60 is the value of QKD (which depends on pulse wave velocity) for 100 mm Hg sBP and 60 bpm HR. The reproducibility of QKD100-60 was assessed on the first patients to be followed up for a complete year. So far the 100 patients have been recruited from 14 participating centres and 48 were re-evaluated after 1 year. QKD100-60 was highly reproducible: 201 +/- 6 vs 202 +/- 18 msec, standard deviation of difference = 13 msec. In conclusion: determination of QKD100-60 to assess arterial stiffness gives stable results over 1 year in patients with systemic sclerosis.

Journal of Human Hypertension (2002) 16, 627-630.
doi: 10.1038/sj.jhh.1001466

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Reduction in Arterial Distensibility in Hypertensive Patients as Evaluated by Ambulatory Measurement of the QKD Interval Is Correlated With Concentric Remodeling of the Left Ventricle


Philippe Gosse, Veronique Jullien. Philippe Jarnier. Philippe Lernetayer, and Jacques Clementy
Relationships between ambulatory arterial pressure and arterial distensibility as assessed by ambulatory measure of the QKD interval and echocardiographic measurement of left ventricular mass and relative wall thickness were evaluated in a population of 163 untreated hypertensive patients. The height-corrected QKD100-60 interval was significantly correlated with left ventricular mass (LVM; r = -0.29, P < .001) and with relative wall thickness (r = -0.31, P < 0.001). In a multivariate analysis, LVM was significantly correlated with mean arterial pressure, pulse
pressure, and age, whereas the relative wall thickness was correlated with the QKD interval and the mean arterial pressure. The concentric character of the LVH of the hypertensive patient was thus linked to the reduction in arterial distensibility.

Am J Hypertens 1999;12:1252-1255 © 1999 American Journal of Hypertension, Ltd.

Key words: Left ventricular hypertrophy, concentric remodeling, ambulatory blood pressure monitoring, arterial distensibility, QKD interval.

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