Isolated Systolic Hypertension Of The Young Is At Low Risk When Central Blood Pressure Is Low

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1 Università degli Studi di Padova Isolated Systolic Hypertension Of The Young Is At Low Risk When Central Blood Pressure Is Low L. Mos 1, O. Vriz 1, P. Mormino 2, P. Visentin 2, S. Martina 1, A. Zanier 2, E. Benetti 2, G. Garavelli 3, A. Bortolazzi 4, P. Palatini 2 (1) Hospital of San Daniele del Friuli, Department of Cardiology ASS4, San Daniele Del Friuli, Italy (2) University of Padua, Padua, Italy (3) Hospital of Cremona, Cremona, Italy (4) Town Hospital, Rovigo, Italy

2 Background Patients with isolated systolic hypertension (ISH) are at increased risk for cardiovascular disorders. According to recent results from the National Health and Nutrition Examination Survey, ISH is the most common form of hypertension among young men and its prevalence is increasing among young adults. However, little is known about the clinical significance of ISH in the young and data from different studies are still controversial.

3 Aim The aim of the present study was to investigate whether prognosis of young ISH differs according to central blood pressure level.

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5 Subjects And Methods 348 untreated stage 1 hypertensive subjects age=33±10 years blood pressure=145±11/92±6 mmhg 287 systolic-diastolic hypertensives (SDH) 61 isolated systolic hypertensives (ISH): 30 with central systolic blood pressure <121 mmhg (ISH low ) 31 with central systolic blood pressure >121 mmhg (ISH high ) 25 normotensive controls (NT) Follow-up length = 10 years Assessment: ambulatory blood pressure monitoring blood chemistry and albumin excretion rate (AER) echocardiography arterial compliance

6 HDI CR 2000 device The technique involves 30s non-invasive recording of radial artery waveform by applanation tonometry which measures the relative intra-arterial pulse amplitude. Arterial compliance was obtained by a software that analyzed the DBP contour and divided the total compliance in CENTRAL (or capacitative C1) and PERIPHERAL (or oscillatory, reflective, C2) compliance.

7 Specaway DAT System Central BP, PWV and AIx Recording at the radial artery Recording at the carotid artery AIx was calculated as the differences between the pressure at the 2 shoulder and DBP to that between at the 1 inflaction and DBP divided PP. PWV (D/Δt) was determined by the simoultaneous applanation tonometry and ECG recording where D= distance between 2 sampling sites and Δt = the time of waveform traveling. Central BP: a transfer function converts radial and carotid to aortic pressure waveform and central pressure

8 Baseline Characteristics (1) Variable NT ISH low ISH high SDH Age (years) 35.4± ± ± ±9.0 Sex (%female) BMI Kg/m ± ± ± ±3.8 Height (cm) 174.8± ± ± ±9.0 AER (mg/24h) 19.4± ± ± ±29.2 LVM (g/m 2 ) 76.9± ± ± ±16.7

9 Blood Pressure At The Baseline Variable NT ISH low ISH high SDH Clinic SBP Clinic DBP Clinic HR (beat/min) 24 h SBP 24 h DBP 24 h HR (beat/min) 128.4± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±8.0

10 Arterial Compliance (1) Variable NT ISH low ISH high SDH p value ISH high vs NT SDH vs NT C1 ml/mmhgx10 C2 ml/mmhgx100 aortic AIx from radial (%) aortic AIx from carotid (%) 16.8± ±5.4* 15.0± ± ± ±2.4* 7.0± ± ± ±14.8* 114.9± ±30.0 p < p < ± ±13.7* 112.5± ±26.5 p = p < PWV m/s 7.5± ±1.6* 8.7± ±3.6 ns * All p (ISH low vs NT) = ns

11 Arterial Compliance (2) Variable NT ISH low ISH high SDH aortic SBP from radial aortic DBP from radial aortic SBP from carotid aortic DBP from carotid ISH high vs NT p value SDH vs NT 111.8± ±7.0* 129.5± ± n.s 79.3± ±7.2* 85.8± ±7.5 n.s. n.s ± ±6.0* 133.0± ±16.3 < ± ±7.0* 85.9± ±7.5 n.s. n.s. * All p (ISH low vs NT) = ns

12 Incidence Of Hypertension p = % p = p-values adjusted for age, gender, time, parental hypertension, coffee intake, smoking status, alcohol consumption, degree of physical activity and baseline heart rate.

13 Incidence of Hypertension p = % p = p = ns p-values adjusted for age, gender, time, parental hypertension, coffee intake, smoking status, alcohol consumption, degree of physical activity and baseline heart rate.

14 Predictors Of Hypertension Needing Treatment Variable Coefficient Odds Ratio p value Sex Time Age Smoke Baseline HR SDH ISH high ISH low Data adjusted for parental hypertension, coffee intake, alcohol consumption, degree of physical activity

15 Conclusion These data show that in ISH of the young, the risk of hypertension needing treatment may vary according to the level of central BP. ISH subjects with low central BP have normal arterial compliance and are at low risk of hypertension needing treatment.