Electrical Bioimpedance for Cardiac Output Monitoring, also known as impedance cardiography and thoracic electrical bioimpedance (TEB), is a diagnostic method that non-invasively measures cardiac output. In 1999, the Centers for Medicare & Medicaid Services (CMS) issued a national coverage decision (Coverage Issues Manual 50-54) for TEB for six indications. We have been asked to reevaluate the scope of the existing policy and to consider an additional indication, the management of hypertension. Our decision may take the form of continuing the current policy, noncoverage, limiting coverage, or expanding coverage. In the interim, the current coverage policy remains in force until a new policy decision, if any, is finalized based on our reconsideration. A new policy would be prospective and would not call into question the legitimacy of the claims paid for under the old policy.

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1. A review of the diagnostic test performance of electrical bioimpedance for hemodynamic measurements, specifically cardiac output, stroke volume, contractility, systemic vascular resistance, and thoracic fluid, including the following elements:
   
   
   • comparison of the diagnostic test performance of electrical bioimpedance to alternative tests
     
   • a review of information from clinical literature (if any) on any factors (for example, placement of leads, experience of the operator, comorbid conditions) that may affect the test performance of electrical bioimpedance and the limitations that these factors would place on clinical utility.

2. A review of the clinical literature on the utility of electrical bioimpedance for the following seven indications, with a focus on data demonstrating changes in patient management and/or improved health outcomes from the use of the device:
   
   
   • Noninvasive diagnosis or monitoring of hemodynamics in patients with suspected or known cardiovascular disease
     
   • Differentiation of cardiogenic from pulmonary causes of acute dyspnea
     
   • Optimization of atrioventricular interval for patients with A/V sequential cardiac pacemakers
     
   • Patients with need of determination for intravenous inotropic therapy
     
   • Post heart transplant myocardial biopsy patients
     
   • Cardiac patients with a need for fluid management
     
   • Management of hypertension

3. A review of the setting of the clinical studies of bioimpedance (inpatient vs. outpatient) and issues related to generalizability of data from the inpatient to the outpatient setting.

4. A review of any information available in the clinical studies of the conditions specified in question 2 on training of the persons using the devices and any issues related to this training (e.g. must monitoring data be interpreted only by a cardiologist; does the administration of the test require special training and can it be performed by a non-physician?)

January 2, 2003

A technical error in the technology assessment on Thoracic Electrical Bioimpedance has been identified. The following text should replace the text beginning at the first word of line 1165 (page 61) through the end of line 1172:

The authors commented that the specialist care group was comprised of nationally certified hypertension specialists with special expertise in the treatment of resistant hypertension (it should also be noted that the TEB group was treated by a physician who as a member of the Division of Hypertension and Internal Medicine at the Mayo Clinic was likely to be more expert in treating hypertension than a typical clinician in primary care), and suggested that monitoring with TEB would have a greater benefit when the alternative was management with a community physician. However, it is also possible that the small improvement in the hemodynamic monitoring group was due not only to the use of TEB, but to correct application by the treating physician of the algorithm in the authors' Table 1 that guided the use of TEB in this application. Before it could be known what the benefit of TEB would be in community practice, with treatment decisions made by generalists, the ability of generalists to learn and apply this algorithm in conjunction with TEB would need to be demonstrated and evaluated.

This change does not affect the conclusions of the technology assessment.