Effects of nebivolol and atenolol on small arteries and microcirculatory endothelium-dependent dilation in hypertensive patients undergoing isometric stress.
OBJECTIVE
To examine the effects on small arteries and on the cutaneous microcirculatory system of nebivolol and atenolol in hypertensive patients.


METHODS
Twenty hypertensive patients were randomly assigned to receive nebivolol or atenolol in a single-blind, placebo-controlled cross-over study. Piezoelectric plethysmography on the third finger, laser Doppler on the third finger at rest and after iontophoretic administration of acetylcholine, and pressure-heart rate monitoring, were carried out both at rest and during handgrip. The tests were performed 45 min after 5 mg nebivolol or 100 mg atenolol administration, then repeated 2 days later with a placebo and, after a further 2 days, with atenolol or nebivolol again.


RESULTS
Both atenolol and nebivolol reduced diastolic blood pressure values and heart rate, as well the increase of blood pressure and heart rate during handgrip. No change was recorded after placebo. Piezoelectric plethysmography showed a significant increase in the ratio between time to peak and total time (PT/TT), calculated on the sphygmic wave, during handgrip (0.295 0.005 versus 0.231 0.015, P<0.005). After nebivolol, a decrease was recorded in rest conditions (0.185 0.008 versus 0.231 0.015, P<0.005) with no statistically significant increase during handgrip, whereas atenolol showed an increase in the PT/TT ratio at rest, with a sustained response during handgrip. Laser Doppler showed an increased response to acetylcholine only after nebivolol.


CONCLUSIONS
Nebivolol and atenolol significantly reduced diastolic blood pressure and heart rate, favourably modulating response to handgrip. Nebivolol improved small artery distensibility index. Endothelium-dependent cutaneous vasodilation after acetylcholine demonstrated a lack of response with atenolol whereas nebivolol favourably acts on endothelial function.
Internal Medicine and Division of Cardiovascular Rehabilitation, University of Verona, Valeggio, Verona, Italy. riabvasc@mail.univr.it
Enrico
E
Arosio
Sergio
S
De Marchi
Manlio
M
Prior
Massimo
M
Zannoni
Alessandro
A
Lechi
D000109:Acetylcholine / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D001158:Arteries / Q000187:drug effects*; D001262:Atenolol / Q000627:therapeutic use*; D001578:Benzopyrans / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D018592:Cross-Over Studies; D003971:Diastole; D004730:Endothelium, Vascular / Q000503:physiopathology; D004983:Ethanolamines / Q000627:therapeutic use*; D005260:Female; D018737:Hand Strength; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology*; D007537:Isometric Contraction; D008297:Male; D008833:Microcirculation / Q000187:drug effects*; D008875:Middle Aged; D000068577:Nebivolol; D016037:Single-Blind Method; D013312:Stress, Physiological / Q000503:physiopathology; D013997:Time Factors; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology
D000319:Adrenergic beta-Antagonists; D001578:Benzopyrans; D004983:Ethanolamines; D014665:Vasodilator Agents; D000068577:Nebivolol; D001262:Atenolol; D000109:Acetylcholine