Effects of sodium nitroprusside on left ventricular diastolic pressure-volume relations.
Key result
Sodium nitroprusside infusion significantly reduced left ventricular end-diastolic pressure from 19 to 9 mm Hg and produced a downward shift in the diastolic pressure-volume curve in patients with congestive heart failure.
Why the study?
Does sodium nitroprusside alter left ventricular diastolic pressure-volume relations in patients with congestive heart failure?
Population
11 patients with congestive heart failure, plus 6 additional control subjects
Comparison
Sodium nitroprusside infusion titrated to lower… vs Baseline measurements before infusion, and a…
Design
Cohort
Follow-up
Acute (during infusion / 15 minutes apart)
Authors
Discussion
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Implication
May enhance LV compliance with nitroprusside in acute HF; leaves open outcome effects in trials.
Key Points
- To assess how sodium nitroprusside administration alters the relationship between left ventricular pressure and volume during diastole in congestive heart failure.
- Infused sodium nitroprusside to reduce mean arterial pressure by approximately 20 to 30 mm Hg in 11 patients with congestive heart failure.
- Obtained simultaneous high-fidelity left ventricular pressures and biplane or single-plane cineangiography before and during infusion to construct diastolic pressure-volume curves.
- Evaluated 6 control subjects undergoing serial cineangiograms 15 minutes apart without nitroprusside to rule out procedural artifacts.
- Sodium nitroprusside caused a substantial downward displacement of the diastolic pressure-volume curve in 9 of 11 patients, yielding lower left ventricular pressure at any given volume.
- Serial cineangiography in 6 control patients showed no shift in the diastolic pressure-volume relationship, confirming the effect was specific to nitroprusside.
Study Design
Type
Observational (n=17)
Multicenter
No
Structured PICO
Does sodium nitroprusside alter left ventricular diastolic pressure-volume relations in patients with congestive heart failure?
P
Population
11 patients with congestive heart failure, plus 6 additional control subjects
I
Intervention
Sodium nitroprusside infusion titrated to lower mean arterial pressure by approximately 20-30 mm Hg
C
Comparator
Baseline measurements before infusion (within-subject), and a control group of 6 subjects undergoing serial cineangiograms 15 minutes apart without nitroprusside
O
Outcome
Left ventricular diastolic pressure-volume relationshipsurrogate
Main Result
Absolute Event Rate: 9% vs 19%
p-value: p=<0.005
Sodium nitroprusside acutely improves left ventricular diastolic distensibility (downward shift of the pressure-volume curve) in patients with congestive heart failure.
Limitations
- Small sample size
- Inability to definitively isolate the exact mechanism of the pressure-volume curve shift (e.g., relaxation vs. viscoelastic properties vs. extrinsic constraints)
- Potential confounding effects of reduced arterial pressure on peak negative dP/dt measurements
Cite This Study
Brodie et al. (1977) conducted an observational in Congestive heart failure (n=17). Sodium nitroprusside vs. Baseline (pre-infusion) was evaluated on Left ventricular end-diastolic pressure (mm Hg) (p=<0.005). Sodium nitroprusside infusion significantly reduced left ventricular end-diastolic pressure from 19 to 9 mm Hg and produced a downward shift in the diastolic pressure-volume curve in patients with congestive heart failure.