What question did this study set out to answer?

To determine whether circulating angiotensin II is preserved and contributes to supine hypertension in autonomic failure patients despite suppressed plasma renin activity.

December 24, 2012HypertensionOpen Access

Angiotensin II, Independent of Plasma Renin Activity, Contributes to the Hypertension of Autonomic Failure

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Why the study?

Does losartan reduce supine systolic blood pressure in patients with hypertensive autonomic failure?

Population

11 patients with hypertensive autonomic failure (and 10 matched healthy controls for baseline comparison)

Comparison

Losartan 50 mg administered at bedtime vs Placebo

Design

RCT, randomized, double-blind, placebo-controlled

Follow-up

overnight (up to morning)

Authors

AAAmy C. ArnoldGeneral Cardiology LOLuis E. OkamotoGeneral Cardiology AGAlfredo GamboaUnited States Nuclear Regulatory Commission

Discussion

Member takes

Implication

Losartan acutely lowers supine SBP in hypertensive autonomic failure; confirms Ang II role independent of renin and supports targeted AT1 blockade.

Key Points

To determine whether circulating angiotensin II is preserved and contributes to supine hypertension in autonomic failure patients despite suppressed plasma renin activity.
Measured circulating angiotensin II and plasma renin activity in hypertensive autonomic failure patients (n=11) and matched healthy controls (n=10).
Conducted a randomized, double-blind, placebo-controlled trial administering the AT1 receptor blocker losartan (50 mg) at bedtime in autonomic failure patients (n=11), alongside captopril testing in a subset.
Circulating angiotensin II was significantly higher in autonomic failure patients than controls (52±5 vs 27±4 pg/mL; P=0.002), despite similarly suppressed plasma renin activity (0.19±0.06 vs 0.34±0.13 ng/mL per hour; P=0.449).
Bedtime losartan maximally lowered systolic blood pressure by 32±11 mm Hg at 6 hours post-dose (P<0.05) and reduced nocturnal urinary sodium excretion (P=0.0461) without worsening morning orthostatic tolerance, whereas captopril had no effect.

Structured PICO

Does losartan reduce supine systolic blood pressure in patients with hypertensive autonomic failure?

Population

11 patients with hypertensive autonomic failure (and 10 matched healthy controls for baseline comparison)

Intervention

Losartan 50 mg administered at bedtime

Comparator

Placebo

Outcome

Supine systolic blood pressuresurrogate

Angiotensin II contributes to supine hypertension in autonomic failure independently of plasma renin activity, and AT1 receptor blockade with losartan effectively lowers blood pressure in these patients.

Cite This Study

Arnold et al. (2012) studied this question.

synapsesocial.com/papers/69d575f4c928a9acfd89a2e3 https://doi.org/10.1161/hypertensionaha.111.00377

Topics

Hypertension management

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Implication

Losartan acutely lowers supine SBP in hypertensive autonomic failure; confirms Ang II role independent of renin and supports targeted AT1 blockade.

Angiotensin II, Independent of Plasma Renin Activity, Contributes to the Hypertension of Autonomic Failure

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Topics

Angiotensin II, Independent of Plasma Renin Activity, Contributes to the Hypertension of Autonomic Failure

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Topics

Also Consider