What question did this study set out to answer?

To determine the contributions of beta-adrenergic stimulation, wall mass, and intrinsic contractility to left ventricular function and to examine wall stress normalization during renovascular hypertension.

July 1, 1993AJP Heart and Circulatory Physiology

Left ventricular adaptation to gradual renovascular hypertension in dogs

Q: What is the clinical evidence from this study?

Study design: Other. Population: Renovascular hypertension and pressure-overload hypertrophy. Intervention: Gradual constriction of one renal artery and acute beta-blockade vs. Unblocked state / baseline. Primary outcome: Changes in hemodynamics, LV dimensions, contractility indexes, and circumferential wall stress.

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Key result

Gradual renovascular hypertension in dogs improved LV pump function through beta-adrenergic stimulation, increased intrinsic contractility, and wall mass, while normalizing end-diastolic wall stress.

Why the study?

Does acute beta-blockade affect LV pump function and wall stress in dogs with gradual renovascular hypertension?

Population

Intact-chest dogs with pressure overload induced by gradual constriction of one renal artery

Comparison

Acute beta-blockade vs Unblocked state (baseline)

Design

Preclinical

Follow-up

12 wk

Authors

TNTuấn Ngọc NguyễnTon Duc Thang University ACAndrezza Campos ChagasNational Institutes of Health SGStanton A. GlantzPreventive Cardiology

Discussion

Member takes

Implication

Animal data link beta-adrenergic drive to LV adaptation in renovascular hypertension; leaves open human relevance and acute beta-blocker effects.

Key Points

To determine the contributions of beta-adrenergic stimulation, wall mass, and intrinsic contractility to left ventricular function and to examine wall stress normalization during renovascular hypertension.
Induced chronic pressure overload in intact-chest dogs through gradual unilateral renal artery constriction over 12 weeks.
Implanted radiopaque markers via catheter into the left ventricular endocardium to measure chamber dimensions and circumferential wall stress.
Assessed hemodynamics, contractility indices including maximal elastance (Emax) and dP/dtmax, and wall stress before and after acute beta-blockade.
Cardiac output, systolic pressure, stroke work, and Emax increased over 12 weeks, with contractility improvements persisting despite acute beta-blockade.
Maximal elastance and dP/dtmax were independent of left ventricular mass increases, whereas stroke work showed borderline dependence on wall mass.
Left ventricular systolic wall stress decreased significantly over time, while end-diastolic wall stress initially increased and subsequently normalized to baseline as hypertrophy developed.

Structured PICO

Does acute beta-blockade affect LV pump function and wall stress in dogs with gradual renovascular hypertension?

Population

Intact-chest dogs with induced pressure overload by gradual constriction of one renal artery, followed for 12 weeks.

Intervention

Acute beta-blockade

Comparator

Unblocked state (baseline)

Outcome

Changes in hemodynamics, LV dimensions, contractility indexes, and circumferential wall stresssurrogate

In a canine model of renovascular hypertension, improved LV pump function is driven by beta-adrenergic stimulation, intrinsic contractility, and wall mass, while hypertrophy normalizes end-diastolic rather than peak-systolic wall stress.

Cite This Study

Nguyễn et al. (1993) studied Renovascular hypertension and pressure-overload hypertrophy. Gradual constriction of one renal artery and acute beta-blockade vs. Unblocked state / baseline was evaluated on Changes in hemodynamics, LV dimensions, contractility indexes, and circumferential wall stress. Gradual renovascular hypertension in dogs improved LV pump function through beta-adrenergic stimulation, increased intrinsic contractility, and wall mass, while normalizing end-diastolic wall stress.

synapsesocial.com/papers/6a9fddc1b95bc43c2fd55aa1 https://doi.org/10.1152/ajpheart.1993.265.1.h22

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Bookmark

Implication

Animal data link beta-adrenergic drive to LV adaptation in renovascular hypertension; leaves open human relevance and acute beta-blocker effects.

Left ventricular adaptation to gradual renovascular hypertension in dogs

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Left ventricular adaptation to gradual renovascular hypertension in dogs

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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