P-283: Compliance of peripheral conduit arteries is increased in isolated systolic hypertension accompanied by left ventricular hypertrophy, a life-substudy

The aim of the study was to evaluate compliance of middle-sized conduit arteries in patients with isolated systolic hypertension (ISH) and high prevalence of left ventricular hypertrophy (LVH). Included were 58 patients, 24F and 34M, age 69 years (55-80) with ECG-determined LVH and they were examined after 14 days on placebo treatment. Arterial compliance was measured on the upper arm using a volume-oscillometric method (Artcomp®, Critikon® ). In results overall BP was 163 ± 22/89 ± 14 mmHg. ISH defined as SBP > 149 mmHg and DBP < 90 mmHg was found in 14 patients (7 males/7 females) with BP 161 ± 12/79 ± 10 mmHg. Arterial compliance at isobaric pressures was the same in the two groups (ns) and increased compared to normals at any transmuralpressure (p<0.01). Arterial compliance at mean arterial BP (MAP) was 3.2 ± 1.4 µl/mmHg/12 cm in the ISH and 2.6 ± 1.0 µl/mmHg/12 cm in the non-ISH patients (p=0.05). Arterial compliance at MAP was increased compared to normals (2.3 ± 1.0 µl/mmHg/12 cm) in ISH only (p<0.05). A positive correlation was seen between pulse pressure (PP) and arterial compliance at MAP (r=0.53, p<0.001) for the 58 patients. Results are controlled for age, gender, BMI and HR. In conclusion peripheral compliance of middle-sized conduit arteries at MAP is normal in non-ISH hypertension in contrast to earlier belief, but in agreement with findings of other groups. But in ISH, peripheral compliance at MAP is increased compared to normals and in all patients, compliance at MAP correlates positively to PP. This could be interpreted as a peripheral adaptation to a decreased central compliance and an increased PP. The underlying mechanisms might be increased stretch of the elastic fibers in the vessel wall or perhaps more likely decreased muscle tone and could be more pronounced when accompanied by LVH.