Cardiac Hemodynamic Monitoring for the Management of Heart Failure in the Outpatient Setting
DESCRIPTION
A variety of outpatient setting cardiac hemodynamic monitoring methods have been proposed to decrease episodes of acute decompensation in individuals with heart failure and thus improve quality of life and reduce morbidity. Four methods will be reviewed here: thoracic bioimpedance, inert gas rebreathing, arterial waveform during Valsalva, and implantable pressure monitoring devices.
Thoracic Bioimpedance
Bioimpedance is defined as the electrical resistance of tissue to the flow of current. For example, when small electrical signals are transmitted through the thorax, the current travels along the blood-filled aorta, which is the most conductive area. Changes in bioimpedance, measured at each beat of the heart, are inversely related to pulsatile changes in volume and velocity of blood in the aorta. Cardiac output is the product of stroke volume by heart rate, and thus can be calculated from bioimpedance. Cardiac output is generally reduced in patients with systolic heart failure. Acute decompensation is characterized by worsening of cardiac output from the patient’s baseline status. The technique is alternatively known as impedance plethysmography and impedance cardiography (ICG).
Inert Gas Rebreathing
This technique is based on the observation that the absorption and disappearance of a blood-soluble gas is proportional to cardiac blood flow. The patient is asked to breathe and rebreathe from a rebreathing bag filled with oxygen mixed with a fixed proportion of two inert gases; typically nitrous oxide and sulfur hexafluoride. The nitrous oxide is soluble in blood and is therefore absorbed during the blood’s passage through the lungs at a rate that is proportional to the blood flow. The sulfur hexafluoride is insoluble in blood and therefore stays in the gas phase and is used to determine the lung volume from which the soluble gas is removed. These gases and carbon dioxide are measured continuously and simultaneously at the mouthpiece.
Arterial Pressure during Valsalva to estimate LVEDP (left ventricular end diastolic pressure)
LVEDP is elevated in the setting of acute decompensated heart failure. While direct catheter measurement of LVEDP is possible for an individual undergoing cardiac catheterization for diagnostic or therapeutic reasons, its invasive nature precludes outpatient use. Noninvasive measurements of LVEDP have been developed based on the observation that arterial pressure during the strain phase of the Valsalva maneuver may directly reflect the LVEDP. Arterial pressure responses during repeated Valsalva maneuvers can be recorded and analyzed to produce values that correlate to the LVEDP.
Pulmonary Artery Pressure Measurement to estimate LVEDP
LVEDP can also be approximated by direct pressure measurement of an implantable sensor in the pulmonary artery wall. The sensor is implanted via right heart catheterization and transmits pressure readings wirelessly to external monitors.
Examples of devices used for this technology include the Innocor® (Innovision, Denmark) inert gas rebreathing device and the VeriCor® (CVP Diagnostics, Boston, MA) device.
POLICY
Cardiac hemodynamic monitoring for the management of heart failure utilizing thoracic bioimpedance, inert gas rebreathing, arterial pressure/Valsalva, and implantable direct pressure monitoring of the pulmonary artery in the outpatient setting is considered investigational.
IMPORTANT REMINDERS
ADDITIONAL INFORMATION
In the absence of well-designed randomized controlled trials, no conclusions can be drawn about whether cardiac hemodynamic monitoring for the management of heart failure utilizing thoracic bioimpedance, inert gas rebreathing, arterial pressure/Valsalva, and implantable direct pressure monitoring of the pulmonary artery in the outpatient setting has an effect on health outcomes.
SOURCES
Abraham, W. T., Adamson, P. B., Bourge, R. C., Aaron, M. F., Costanzo, M. R., Stevenson, L. W., et al. (2011). Wireless pulmonary artery haemodynamic monitoring in chronic heart failure: A randomised controlled trial. Lancet, 377 (9766), 658-666. (Level 1 Evidence - Industry sponsored)
BlueCross BlueShield Association. Medical Policy Reference Manual. (7:2011). Cardiac hemodynamic monitoring for the management of heart failure in the outpatient setting (2.02.24). Retrieved September 21, 2011 from BlueWeb. (22 articles and/or guidelines reviewed)
Complete Guide to Medicare Coverage Issues [Computer software]. (2011, August). Cardiac output monitoring by thoracic electrical bioimpedance (TEB) (NCD 20.16, p. 2-22). Ingenix.
Feliciano, J., Soares, R., Silva, S., Fiarresga, A., Fernandes, R. M., Miranda, F., et al. (2007). NT-proBNP levels and resting hemodynamic parameters assessed by bioimpedance in patients with chronic heart failure. Portuguese Journal of Cardiology, 26 (10), 1021-1028. (Level 4 Evidence - Independent study)
Jessup, M., Abraham, W. T., Casey, D. E., Feldman, A. M., Francis, G. S., Ganiats, T. G., et al. (2009). 2009 focused update: ACCF/AHA guidelines for the Diagnosis and Management of Heart Failure in Adults: A report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines: Developed in collaboration with the International Society for Heart and Lung Transplantation. Circulation, 119 (14), 1977-2016.
Lang, C. C., Karlin, P., Haythe, J., Lim, T. K., & Mancini, D. M. (2009). Peak cardiac power output, measured noninvasively, is a powerful predictor of outcome in chronic heart failure. Circulation. Heart Failure, 2 (1), 33-38. (Level 4 Evidence - Independent study)
Ramsay, J. (2006). Noninvasive technologies for tissue perfusion. Anesthesiology Clinics, 24 (4), 763-775.
Sobanski, P., Sinkiewicz, W., Kubica, J., Blazejewski, J., & Bujak, R. (2008). The reliability of noninvasive cardiac output measurement using the inert gas rebreathing method in patients with advanced heart failure. Cardiology Journal, 15 (1), 63-70. (Level 4 Evidence - Independent study)
Sodolski, T., & Kutarski, A. (2007). Impedance cardiography: A valuable method of evaluating haemodynamic parameters. Cardiology Journal, 14 (2), 115-126.
U. S. Food and Drug Administration. (2005, June). Center for Devices and Radiological Health. 510(k) Premarket Notification Database. K051228. Retrieved February 15, 2011 from http://www.accessdata.fda.gov/cdrh_docs/pdf5/K051228.pdf.
U. S. Food and Drug Administration. (2009, May). Center for Devices and Radiological Health. 510(k) Premarket Notification Database. K090602. Retrieved February 15, 2011 from http://www.accessdata.fda.gov/cdrh_docs/pdf9/K090602.pdf.
Winters, M. E., McCurdy, M. T., & Zilberstein, J. (2008). Monitoring the critically III emergency department patient. Emergency Medicine Clinics of North America, 26 (3), 741-757.
ORIGINAL EFFECTIVE DATE: 2/1/2004
MOST RECENT REVIEW DATE: 1/14/2012
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