Medicine Section - Non-invasive Measurement of Left Ventricular End Diastolic Pressure (LVEDP) in the Outpatient Setting

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Description

LVEDP is elevated in the setting of congestive heart failure and its measurement may be useful in the management of patients with heart failure. However, to date, measurement of LVEDP has only been performed in the inpatient setting, since its measurement requires cardiac catheterization, either by direct measurement by placing a catheter in the left ventricle or indirect measurement by placing a catheter in the pulmonary artery to measure the pulmonary capillary wedge pressure. Noninvasive measurements of LVEDP have been developed based on the observation that the arterial pressure during the strain phase of the Valsalva maneuver may directly reflect the LVEDP. For example, arterial pressure response during the Valsalva maneuver generally shows 4 distinct phases, which can be recorded and analyzed. The VeriCor device (CVP Diagnostics, Boston MA) is an example of a device for the noninvasive measurement of LVEDP that has received U.S. Food and Drug Administration (FDA) clearance through the 510(k) process with the following labeled indication: “The VeriCor is indicated for use in estimating non-invasively, left ventricular end-diastolic (LVEDP) pressure. This estimate, when used along with clinical signs and symptoms and other patient test results, including weights on a daily basis, can aid the clinician in the selection of further diagnostic tests in the process of reaching a diagnosis and formulating a therapeutic plan when abnormalities of intravascular volume are suspected. The device has been clinically validated in males only. Use of the device in females has not been investigated.”

The VeriCor device consists of a digital expiratory manometer coupled with a continuous arterial pressure monitor and a medical grade computer. A tonometric sensor is attached to the patient’s wrist with a blood pressure cuff attached to the arm. After an 8 minute tonometric calibration period is completed, the VeriCor system is ready for using. For the test, the patient is prompted to perform a Valsalva maneuver by blowing into the mouthpiece of the digital manometer to produce an expiratory pressure of 20 to 30 mmHg for a minimum of eight seconds. The digital signals are collected and stored on a medical grade computer. The arterial pressure signals are then analyzed according to algorithms that were developed to most accurately predict pulmonary capillary wedge pressure. The FDA labeling also notes that the Valsalva maneuver may be contraindicated in a variety of cardiovascular conditions, including for example, hypertrophic obstructive cardiomyopathy, significant aortic valvular disease, and recent myocardial infarction.

Policy/Criteria

Noninvasive measurement of left ventricular end diastolic pressure (LVEDP) in the outpatient setting is considered investigational.

Scientific Background

Evaluation of a diagnostic technology typically consists of three steps: 1) evaluation of the technical performance of the test; 2) determination of the correlation of the technology to the gold standard of testing (i.e., noninvasive measurement of LVEDP to the gold standard of direct measurement of LVEDP with left heart catheterization or to pulmonary capillary wedge pressure), and 3) evaluation of the impact on the clinical management of the patient and a determination of whether the changes in clinical management based on the test result in an improvement in overall health outcomes.

The ability to perform measurements of LVEDP noninvasively permits the outpatient use of this technology and potentially broadens the patient selection criteria for LVEDP measurement. For example, using conventional techniques, measurement of LVEDP was only performed in hospitalized patients whose symptoms were serious or unstable enough to warrant cardiac catheterization. The noninvasive measurement of LVEDP permits its use in non-acute settings, such as in the outpatient clinic as part of the ongoing management of stable patients. The manufacturer suggests that the device may be used to determine the need for hospitalization, or to monitor patients with heart failure to maintain LVEDP within a targeted range to prevent future hospitalizations.

Technical Feasibility

Measurement of the arterial wave form is an accepted and technically feasible technology.

Diagnostic Performance

Studies have shown a high correlation between invasive and non-invasive measurement of LVEDP. For example, McIntyre and colleagues reported that the two techniques were highly correlated in both stable and unstable and catheterized patients. (R= 0.80-0.85) (2) More recently, Sharma and colleagues performed simultaneous measurements of the LVEDP based on three techniques in patients with coronary artery disease: direct measurement of LVEDP, considered the gold standard, indirect measurement using pulmonary capillary wedge pressure (PCWP) and non-invasively using the VeriCor device in 49 patients. All patients first received cardiac catheterization for LVEDP and PCWP measurements followed immediately with Valsalva strain measurements. (3) The VeriCor measurements correlated well with the direct measures of LVEDP (correlation coefficient, r=0.86) and outperformed the PCWP which had a correlation coefficient of 0.81 compared to the gold standard.

Impact on Clinical Management

An updated search of the MEDLINE database through December 24, 2008 failed to identify any published articles that evaluated the role of noninvasive measurement of the LVEDP on the management of the patient. Therefore, there is inadequate data to permit scientific conclusions regarding the clinical utility of this technology. For example, there were no studies that examined whether including routine measurement of LVEDP in the outpatient setting resulted in improved management of congestive heart failure, as evidenced by improvement in the clinical signs and symptoms or the need for hospitalization.

References

1. BlueCross and BlueShield Association Medical Policy Reference Manual. Policy No. 2.02.21
2. McIntyre KM, Parisi AF, Brown R et al. Validation and clinical applications of a noninvasive Valsalva response recorder. J Appl Cardiol 1987;2:137-169
3. Sharma GVRK, Woods PA, Lambrew CT et al. Evaluation of a noninvasive system for determining left ventricular filling pressure. Arch Int Med 2002;162:2084-88

Cross References

Noninvasive Mesaurements of Cardiac Hemodynamics in the Outpatient Setting, Regence Medical Policy, Medicine No. 33

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