Arterial stiffness-a predictor of myocardial stiffness in early hypertension

AJH–May 2005–VOL. 18, NO. 5, PART 2

function (EF), this is an expensive and observer dependent technique. The aim of this study was to to evaluate a new technique to assess endothelial function, using fingertip perfusion measurement by Voyager Pulse Oximeter from Dolphin Medical installed in HpTM pocket PC. All data were collected from 31 healthy young volunteers, 15 females and 16 males with 21.7⫾1.5 years of age, MCI 21.7⫾5.6. After 5 minutes resting in supine position, Doppler evaluation of brachial artery was performed and local perfusion data from Dolphin device placed in index fingertip was recorded. Sphygmomanometer’s cuff was then kept inflated 50 mmHg above the rest systolic blood pressure value for 5 minutes. New measurements were obtained one minute after cuff deflation, in the phase of endothelial hyperemia, and after five minutes. Results were compared between the two methods. Sensibility of local perfusion measurement was 91.7%. Specificity results weren’t calculated since only healthy volunteers were tested. In conclusion, this new device has a high sensibility in the evaluation of endothelial function, but it’s less expensive, not dependent on observer and easier to perform compared with the gold standard arterial color Doppler. Key Words: Atherosclerosis, Endothelial Dysfunction, Local Perfusion

P-23 AUGMENTATION INDEX AND PULSE WAVE VELOCITY: DO BOTH MEASURE ARTERIAL STIFFNESS? Azra Mahmud, John Feely. Clinical Pharmacology & Therapeutics & Hypertension Clinic, St. James’s Hospital, Dublin, Ireland. Pulse wave velocity (PWV) and augmentation index (AIx) are used interchangeably as measures of arterial stiffness.We looked at the relationship between these in 400 untreated hypertensive patients. Patients studied supine and brachial blood pressure (BP) and heart rate(HR) measured with an oscillometric device (Omron).Carotid-femoral PWV measured with Complior and aortic BP,AIx and pulse wave transit time,TR derived with SphygmoCor and pulse pressure (PP) amplification (aortic PP- brachial PP) calculated.Statistical analysis performed with JMP version 5 using non-parametric tests and multiple regression.Data expressed as mean⫾SEM and p⬍0.05 considered significant.The mean age was 49⫾0.65 years, 188 females.Mean PWV was 10.5⫾0.1 m/sec, significantly higher in men vs women (10.6⫾0.2 vs 10.1⫾0.2, p⬍0.001). Mean AIx was 29⫾0.6;women had higher AIx than men (33⫾0.9 vs 25⫾0.8, p⬍0.0001).Mean TR was 135⫾0.7, significantly shorter in women vs men (131⫾1 vs 139⫾0.8, p⬍0.0001). PWV was positively related to age ( r⫽0.58, p⬍0.0001),systolic BP (r⫽0.54, p⬍0.0001),AIx( r⫽0.22, p⬍0.0001) and negaitively with TR ( r⫽-0.18,p⬍0.001).The AIx was positively related to age (r⫽0.39, p⬍0.0001), systolic BP (r⫽0.36, p⬍0.0001)and negatively to PP amplification(r⫽-0.79, p⬍0.0001), TR (r⫽-0.52, p⬍0.0001)height(r⫽ 0.42,p⬍0.0001)and HR(r⫽-0.36, p⬍0.0001).Using multiple regression model with log (PWV) as the dependent variable, age and systolic BP were the strongest determinants followed by gender, HR and AIx, in that order. PWV increased with age, systolic BP, heart rate and AIx, and decreased with female gender. Overall, the model explained 47% of the variance in log (PWV).Using AIx as the dependent variable, age, HR, height and diastolic BP were the strongest determinants of AIx, followed by gender and PWV. The AIx increased with age, diastolic BP, female gender and PWV and decreased with HR and height.Overall, the model explained 54% of the variance in AIx.In hypertensive patients, there is a weak relationship between AIx and PWV suggesting these parameters may measure different arterial properties and should be used as complimentary measures than just alternatives.PWV is primarily determined by age and BP whereas AIx, more complex,depends upon age, body size and HR with BP less important.Also, TR, used as surrogate for aortic PWV, is weakly related to PWV and may be an inaccurate method for estimating aortic PWV. Key Words: Aaugmentation Index, Arterial Compliance, Pulse Wave Velocity

POSTERS: Arterial Structure and Compliance

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P-24 ARTERIAL STIFFNESS-A PREDICTOR OF MYOCARDIAL STIFFNESS IN EARLY HYPERTENSION Azra Mahmud, Ibrahim Almuntasir, Gerard King, John Feely, Crean Peter. Clinical Pharmacology & Therapeutics & Hypertension Clinic, Trinity College & St. James’s Hospital, Dublin, Ireland; Cardiology, Trinity College & St. James’s Hospital, Dublin, Ireland. Arterial stiffness an independent predictor of cardiovascular and all cause mortality in hypertensive patients. Left ventricular diastolic dysfunction(LVDD) i.e.,incomplete relaxation of the ventricle during early diastolic filling, is quite pravelent in hypertension. We hypothesized that hypertensive subjects with stiffer arteries will also have higher left ventricular stiffness. We studied 60 subjects with untreated essential hypertension mean age 48⫾2, 30 female. Brachial BP and heart rate(HR) measured with an automated BP monitor (Omron). Aortic pressure waveform derived by applanation tonometry (SphygmoCor) aortic systolic and diastolic BP and mean BP, augmentation index (AIx%), a measure of aortic wave reflection, and pulse pressure (PP) amplification( brachial PP-aortic PP) derived. Aortic stiffness measured by carotid-femoral pulse wave velocity (PWV) with Complior. Diastolic function was assesed by conventional Doppler and Tissue Doppler imaging (TDI).Peak early (E) and late(A) of transmitral and mitral annular velocities and E/A ratio measured. Statistical analysis was performed with JMP version 5,results are expressed as Mean⫾SEM, p⬍0.05 considered significant. 30 patients had LVDD with higher PWV (10.8⫾0.3 vs 9.6⫾0.2,p⬍0.01) and AIx(30⫾2 vs 22⫾2,p⬍0.01) than those with normal diastolic function. E/A inversely correlated with AIx (r⫽-0.30,p⬍0.01), HR corrected AIx (R⫽-0.45, p⬍0.0001), age (r⫽-0.46, p⬍0.001), MBP (r⫽-0.33, p⬍0.05), aortic systolic BP(r⫽-0.28, p⬍0.05) and PWV(r⫽0.33,p⬍0.01) and positively with PP amplification(r⫽0.26, p⬍0.001). The relationship between AIx and E/A was significant when corrected for age and MBP, the model explaining 42% of the variance in E/A. In the subset of patients with diastolic dysfunction (n⫽30), there was a higher correlation between E/A and AIx(r⫽-0.56,p⬍0.001), HR corrected AIx(r⫽-0.66,p⬍0.0001) and PP amplification ( r⫽0.47, p⬍0.001), significant when corrected for age and MBP,the model explained 52% of the variance in E/A. Functional myocardial and vascular abnormalities are very common in early hypertension and stiffness changes in the left ventricle parallel those in the arteries. Therefore a stiff vasculature may predict the development of LVDD and if identified early, these changes may be prevented. Key Words: Aaugmentation Index, Arterial Compliance, Diastolic Dysfunction

P-25 SEVERITY OF METABOLIC SYNDROME ASSOCIATED WITH AORTIC STIFFNESS, ALBUMINURIA AND VENTRICULAR MASS IN TWO HYPERTENSIVE POPULATIONS Joao Maldonado, Susana Bertoquini, Luis Martins, Jose A Silva, Jorge Polonia. Unidade Risco CV e Farmacol Clin, Universidade Fernando Pessoa, Porto, Portugal; Unidade Hipertensao Risco CV, Hospital Pedro Hispano, Matosinhos, Portugal; Faculdade Medicina do Porto, Porto, Portugal. We calculate the prevalence of metabolic syndrome (MS) in representative samples of two hypertensive populations (35-65 yrs) with normal renal function followed in a hospital hypertension reference clinic (HC) and in out-hospital internal medicine clinic (OHC). We evaluate whether higher scores of MS corresponded to greater aortic stiffness, albuminuria and LV mass. Subjects were divided according to 1 to 5 ATP-III criteria were present (BP ⬎ 130/85 mm Hg, Waist ⬎ 102M, 88 cm F, Triglicerides ⬎ 150 mg/dl, HDL-C M,F, Glicemia ⬎ 110 mg/dl) . MS was defined if ATPIII ⬎⫽ 3 criteria. We measured 24h-albuminuria