Validation of Peripheral Pressure Volume Loops and Ultrasound-derived "Cardiac Power" by Comparison With Invasive Left Ventricular Pressure Volume Loops

The investigators will generate pressure-flow loops and pressure-volume loops from aortic and left ventricular pressure waveforms and Doppler (desc. aorta) flow waveforms and compare left ventricular to arterial pressure-flow and pressure-volume loops as well as to cardiac power from the USCOM 1A device. The goal of this study is to test the hypothesis that non-invasive estimates of cardiac pressure-volume work (derived from ultrasound-based measurements) correlate with invasive estimates.

Study Overview

• Status: Completed
• Conditions: Cardiovascular Disease

Detailed Description

Extensive animal work by Suga et al. in the 1980s clearly demonstrate a relationship between left ventricular pressure volume area (PVA) and myocardial consumption of oxygen (MVO2).

PVA can be measured by combining radial artery pressures with ultrasound-derived estimates of aortic blood flow. Because the aorta and peripheral artery compartments are separated from the left ventricle by the aortic valve, the peripheral arterial pressures cannot perfectly approximate left ventricular pressures. However, because the majority of variation in the pressure volume loops is made up of changes in height and width (changes in the left ventricular end-diastolic curve are, by contrast, relatively small), both of which can be readily detected by changes in the peripheral arterial blood pressure tracing, this loss of information may be clinically insignificant.

USCOM, has developed a portable suprasternal Doppler probe (model 1A) capable of estimating left ventricular stroke volume; a unique feature of this device is its ability to utilize both stroke volume, heart rate, and mean arterial pressure in an attempt to measure cardiac power. This device has not been validated against invasive estimates of cardiac power.

Knowledge of MVO2 would be a useful clinical variable but is not widely available. The ability to non-invasively estimate MVO2 intraoperatively would give anesthesiologists the ability to measure the effect of hemodynamic interventions on myocardial consumption of oxygen and, when combined with stroke volume, estimate myocardial efficiency. Non-invasively estimates of MVO2 may also allow cardiologists a novel means of assessing the myocardium of patients with cardiovascular disease.

• Study Type: Observational
• Enrollment (Actual): 65

Contacts and Locations

Study Locations

• United States
  • Virginia
    • Charlottesville, Virginia, United States, 22908
      • University of Virginia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Adults 18 and over undergoing elective left heart catheterization

Description

Inclusion Criteria:

• Adult (18 or older)
• Undergoing left heart catheterization

Exclusion Criteria:

• Unable to visualize ascending aorta using ultrasound

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Elective left heart cath; Patients undergoing elective left heart catheterization will be consented for this study

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between left ventricular pressure volume area (PVA) and aortic PVA	The primary hypothesis of this study is that the slope of the regression line between left ventricular pressure volume area (PVA, as determined by simultaneous measurement of aortic outflow and left ventricular pressures) and aortic PVA (as determined by simultaneous measurement of aortic outflow and radial artery pressure) is not zero. The null hypothesis is that the probability that the slope of the regression line is different from a line with a slope of 0 is greater than 5%.	day of procedure

Collaborators and Investigators

• Sponsor: University of Virginia

Study record dates

Study Major Dates

• Study Start: February 1, 2013
• Primary Completion (Actual): March 1, 2013
• Study Completion (Actual): June 1, 2013

Study Registration Dates

• First Submitted: December 6, 2012
• First Submitted That Met QC Criteria: December 12, 2012
• First Posted (Estimate): December 17, 2012

Study Record Updates

• Last Update Posted (Estimate): May 1, 2014
• Last Update Submitted That Met QC Criteria: April 30, 2014
• Last Verified: April 1, 2014

More Information

Terms related to this study

• Keywords: Myocardial Work; Pressure Volume Area; Pressure Flow Area
• Additional Relevant MeSH Terms: Cardiovascular Diseases
• Other Study ID Numbers: 16494