Ventilatory power: a novel index that enhances prognostic assessment of patients with heart failure.

Abstract

BACKGROUND:

Minute ventilation/CO(2) production (VE/Vco(2)) slope is an index determined by cardiopulmonary exercise testing, which incorporates pertinent cardiac, pulmonary, and skeletal muscle physiology into a substantive composite assessment. The VE/Vco(2) slope has many applications, including utility as a well-validated prognostic gauge for patients with heart failure (HF). In this study, we combine VE/Vco(2) slope with systolic blood pressure, creating a novel index that we labeled ventilatory power. Ventilatory power links the combined physiology inherent in the VE/Vco(2) slope to peripheral pressure, adding an additional dimension pertinent to HF assessment. Whereas the related concept of circulatory power links peak oxygen consumption with peak systolic blood pressure as a prognostic index, we hypothesized that ventilatory power would provide greater prognostic discrimination than VE/Vco2 slope, peak oxygen consumption, and circulatory power for patients with systolic HF.

METHODS AND RESULTS:

Patients with systolic HF (left ventricular ejection fraction ≤35%) underwent symptom-limited cardiopulmonary exercise testing as part of routine management and were followed for up to 4 years for major cardiac events (mortality, left ventricular assist device implantation, and heart transplantation). Eight hundred seventy-five patients with HF (left ventricular ejection fraction, 26±9%; mean age, 55±14) were studied. Cardiopulmonary exercise testing indices peak oxygen consumption, VE/Vco(2) slope, circulatory power, and ventilatory power were all predictive of cardiac events (P<0.001). Multivariate analysis demonstrated that ventilatory power was the strongest indicator of prognosis.

CONCLUSIONS:

Although circulatory power and traditional cardiopulmonary exercise testing parameters can be used to predict prognosis among patients with HF, ventilatory power provides relatively greater prognostic discrimination and may constitute a relatively more useful composite tool.

• Authors: Daniel E Forman, Marco Guazzi, Jonathan Myers, Paul Chase, Daniel Bensimhon, Lawrence P Cahalin, Mary Ann Peberdy, Euan Ashley, Erin West, Karla M Daniels, Ross Arena
• Journal: Circulation. Heart failure (Circ Heart Fail) Vol. 5 Issue 5 Pg. 621-6 (Sep 01 2012) ISSN: 1941-3297 [Electronic] United States
• PMID: 22899767 (Publication Type: Journal Article, Multicenter Study)

Topics

• Adult
• Aged
• Blood Pressure
• Chi-Square Distribution
• Exercise Test
• Female
• Heart Failure (diagnosis, mortality, physiopathology, therapy)
• Heart Transplantation
• Heart-Assist Devices
• Humans
• Italy
• Kaplan-Meier Estimate
• Lung (physiopathology)
• Male
• Middle Aged
• Multivariate Analysis
• Oxygen Consumption
• Predictive Value of Tests
• Prognosis
• Proportional Hazards Models
• Pulmonary Ventilation
• Respiratory Function Tests
• Retrospective Studies
• Risk Assessment
• Risk Factors
• Stroke Volume
• Systole
• Time Factors
• United States
• Ventricular Function, Left