The hemodynamic and neurohormonal effects of low doses of tezosentan (an endothelin A/B receptor antagonist) in patients with acute heart failure.
BACKGROUND
In previous studies (the RITZ project), tezosentan, an intravenous (i.v.)-balanced dual endothelin (ET-A/B) antagonist, in doses of 50 and 100 mg/h, improved the hemodynamics but not the clinical outcome of patients with acute heart failure (AHF).


OBJECTIVE
To evaluate the effect of lower doses of tezosentan in patients with AHF.


METHODS
Included were 130 patients hospitalized due to AHF with dyspnea at rest, despite initial treatment, and were in need of hemodynamic monitoring with cardiac index (CI)<2.5 l/min/m(2) and wedge pressure > or = 20 mm Hg. Patients were randomized in a double-blind fashion to receive placebo or tezosentan: 0.2, 1, 5, or 25 mg/h for 24 h.


RESULTS
The primary endpoint of the study, CI increase at 6 h of treatment, was significant in the 5 and 25 mg/h groups. Tezosentan induced a dose-dependent increase in CI and a decrease in wedge pressure, peaking after 3 h in the 5 and 25 mg/h groups. In the 1 mg/h group, this effect was smaller during the first 6 h and increased gradually, becoming significant at 24 h and beyond treatment discontinuation. There was no hemodynamic effect in the 0.2 mg/h arm. Type-B natriuretic peptide (BNP) decreased in the 1, 5, and 25 mg/h groups but not on placebo. Endothelin levels were significantly increased by the 5 and 25 mg/h groups but not in the lower (< or = 1 mg/h) tezosentan doses. Urine output decreased on the 25 mg/h dose. There was a trend towards improvement in patients' subjective dyspnea score and worsening heart failure events, mainly in the 1 mg/h group.


CONCLUSIONS
In patients admitted with AHF, tezosentan doses of 1-25 mg/h are efficacious in improving the hemodynamics and reducing BNP. Tezosentan doses beyond 1 mg/h increased plasma endothelin levels and reduced urine output, probably limiting their clinical efficacy, as compared to tezosentan 1 mg/h.
The Cardiology Department, Assaf-Harofeh Medical Center, 70300 Zerifin, Israel. cotterg@hotmail.com
Gad
G
Cotter
Edo
E
Kaluski
Karl
K
Stangl
Richard
R
Pacher
Christoph
C
Richter
Olga
O
Milo-Cotter
Loïc
L
Perchenet
Isaac
I
Kobrin
Shoshana
S
Kaplan
Maurizio
M
Rainisio
Aline
A
Frey
Eric
E
Neuhart
Zvi
Z
Vered
Jasper
J
Dingemanse
Guillermo
G
Torre-Amione
D000368:Aged; D004311:Double-Blind Method; D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D065128:Endothelin Receptor Antagonists; D016232:Endothelins / Q000097:blood; D005260:Female; D006333:Heart Failure / Q000188:drug therapy* / Q000503:physiopathology*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D011446:Prospective Studies; D011725:Pyridines / Q000008:administration & dosage / Q000494:pharmacology*; D013777:Tetrazoles / Q000008:administration & dosage / Q000494:pharmacology*
D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D065128:Endothelin Receptor Antagonists; D016232:Endothelins; D011725:Pyridines; D013777:Tetrazoles; D020097:Natriuretic Peptide, Brain; C120582:tezosentan