Haemodynamic, neurohumoral and exercise effects of losartan vs. captopril in chronic heart failure: results of an ELITE trial substudy. Evaluation of Losartan in the Elderly.
BACKGROUND
The AT1 receptor antagonists differ from the angiotensin converting enzyme inhibitors by achieving a more complete blockade of angiotensin II's actions and by not affecting bradykinin metabolism. There is little information on whether this causes clinically significant differences in haemodynamics, neurohormones and exercise tolerance in heart failure.


OBJECTIVE
To compare the effects of losartan and captopril upon central and regional haemodynamics, neurohormones and exercise capacity in heart failure.


METHODS
In a double-blind, randomised trial 18 patients aged > or =65 years with symptomatic heart failure were allocated to treatment with losartan (10 patients) or captopril (eight patients). Patients underwent assessment at baseline, after the first dose, at 12 weeks and at 24 weeks.


RESULTS
Systolic blood pressure fell by - 10.7% 1 h after captopril 6.25 mg (P = 0.007) and by - 4.8% 3 h after losartan 12.5 mg (P = 0.02). The blood pressure reduction was sustained with losartan at 12 and 24 weeks. Systemic vascular resistance fell acutely after captopril (-16.4%, P = 0.01). Captopril caused an acute and sustained rise in superior mesenteric artery blood flow (+ 22.9%, P = 0.04), and a slower rise in renal artery blood flow (+31.7%, P = 0.01). Losartan had no acute effects on regional haemodynamics but had increased superior mesenteric artery blood flow by 38.1% at 12 weeks (P = 0.02). There were no substantial differences between losartan and captopril, and no changes occurred in neurohormones or exercise capacity.


CONCLUSIONS
No substantial differences were observed between losartan and captopril on central or regional haemodynamics, neurohormones or exercise capacity in elderly patients with stable symptomatic heart failure.
Houghton
A R
AR
Department of Cardiovascular Medicine, University Hospital, Queen's Medical Centre, Nottingham, UK. houghtons@talk21.com
Harrison
M
M
Cowley
A J
AJ
D000368:Aged; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D009320:Atrial Natriuretic Factor / Q000097:blood; D002216:Captopril / Q000627:therapeutic use*; D002908:Chronic Disease; D004311:Double-Blind Method; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D019808:Losartan / Q000627:therapeutic use*; D008297:Male; D018377:Neurotransmitter Agents / Q000097:blood*; D009638:Norepinephrine / Q000097:blood; D012083:Renin / Q000097:blood
D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D018377:Neurotransmitter Agents; D009320:Atrial Natriuretic Factor; D002216:Captopril; D012083:Renin; D019808:Losartan; D009638:Norepinephrine