Effects of sodium nitroprusside in aortic stenosis associated with severe heart failure

Pressure-volume loop analysis using a numerical model

Zoran B. Popović, Umesh N. Khot, Gian M. Novaro, Fernando Casas, Neil L. Greenberg, Mario J. Garcia, Gary S. Francis, James D. Thomas

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

In the recently published clinical study [Use of Nitroprusside in Left Ventricular Dysfunction and Obstructive Aortic Valve Disease (UNLOAD)], sodium nitroprusside (SNP) improved cardiac function in patients with severe aortic stenosis (AS) and left ventricular (LV) systolic dysfunction. We explored the possible mechanisms of these findings using a series of numerical simulations. A closed-loop lumped parameters model that consists of 24 differential equations relating pressure and flow throughout the circulation was used to analyze the effects of varying hemodynamic conditions in AS. Hemodynamic data from UNLOAD study subjects were used to construct the initial simulation. Systemic vascular resistance (SVR), heart rate, and aortic valve area were directly entered into the model while end-systolic and end-diastolic pressure-volume (P-V) relationships were adjusted using previously published data to match modeled and observed end-systolic and end-diastolic pressures and volumes. Initial simulation of SNP treatment by a reduction of SVR was not adequate. To obtain realistic model hemodynamics that reliably reproduce SNP treatment effects, we performed a series of simulations while simultaneously changing end-systolic elastance (Ees), end-systolic volume at zero pressure (V 0), and diastolic P-V shift. Our data indicate that either an E es increase or V0 decrease is necessary to obtain realistic model hemodynamics. In five patients, we corroborated our findings by using the model to duplicate individual P-V loops obtained before and during SNP treatment. In conclusion, using a numerical model, we identified ventricular function parameters that are responsible for improved hemodynamics during SNP infusion in AS with LV dysfunction.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume288
Issue number1 57-1
DOIs
StatePublished - Jan 2005
Externally publishedYes

Fingerprint

Aortic Valve Stenosis
Nitroprusside
Heart Failure
Pressure
Hemodynamics
Left Ventricular Dysfunction
Blood Pressure
Aortic Valve
Vascular Resistance
Aortic Diseases
Ventricular Function
Heart Valves
Therapeutics
Heart Rate

Keywords

  • Afterload
  • Contractility
  • Ventricular mechanics

ASJC Scopus subject areas

  • Physiology

Cite this

Effects of sodium nitroprusside in aortic stenosis associated with severe heart failure : Pressure-volume loop analysis using a numerical model. / Popović, Zoran B.; Khot, Umesh N.; Novaro, Gian M.; Casas, Fernando; Greenberg, Neil L.; Garcia, Mario J.; Francis, Gary S.; Thomas, James D.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 288, No. 1 57-1, 01.2005.

Research output: Contribution to journalArticle

Popović, Zoran B. ; Khot, Umesh N. ; Novaro, Gian M. ; Casas, Fernando ; Greenberg, Neil L. ; Garcia, Mario J. ; Francis, Gary S. ; Thomas, James D. / Effects of sodium nitroprusside in aortic stenosis associated with severe heart failure : Pressure-volume loop analysis using a numerical model. In: American Journal of Physiology - Heart and Circulatory Physiology. 2005 ; Vol. 288, No. 1 57-1.
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