gms | German Medical Science

Early atherosclerotic changes are characterized by an impaired endothelium function, which results in either reduced basal nitric oxide (NO) activity or attenuated NO-stimulation. In the current study we examined whether endothelial NO-activity is related with arterial compliance in the large (C1) and small vessels (C2).

We examined 32 patients with hypercholesterolemia (LDL ³ 130 mg/dl) at baseline and after 14 days of statin therapy. Changes in forearm blood flow (FBF) were measured by strain gauge plethysmography in response to increasing doses of intraarterially (i.a.) given acetylecholine (12 and 48µg/min) and i.a. L-NMMA (4 and 8µmol/min). C1 and C2 were detected through waveform analysis with a calibrated tonometer (HDI/PulseWaveÓ system).

Baseline FBF increased at acetylcholine (ACH) 12 µg/min to 325 ± 217% and at ACH 48µg/min to 418 ± 281% (p<0.01). Infusion of L-NMMA 4 and 8 µmol/min produced a reduction in FBF of 32 ± 11 and 41 ± 9%, respectively (p<0.001). Of note, C1 shows a strong correlation with the relative (-0.49, p=0.005) and absolute (-0.55, p=0.001) increase of FBF at ACH 12µg/min. The correlation coefficients for ACH 48µg/min were similar, -0.43 (p=0.014) and -0.49 (p=0.004) respectively. C2 shows a correlation with ACH 12µg/min absolute (-0.412, p=0.019) and relative -0.446, (p=0.011) but not with 48µg/min. After 14 days of statin therapy the change of the response to L-NMMA 4 µg/min was linked to changes of C1 (-0.505, p=0.008).

Our results showed strong relation between invasive measurement of the endothelial NO-activity response to vasoactive substances and the non-invasive determined vascular compliance. Thus, alterations in vascular compliance of small or large arteries are linked to impaired endothelium function thereby offering the possibility to estimate the impairment of endothelial dysfunction by measurement of the peripheral vascular compliance.