The clinical use of contrast echocardiography (ECHO) is appropriate in selected patients to:
Evaluate myocardial ischemia
Quantify myocardial perfusion during stress
Identify the “area at risk” during acute myocardial infarction (AMI)
Determine the success of reperfusion interventions
Assess myocardial viability
The plethora of structural and functional information provided by transthoracic echocardiogram (TTE) is unique among diagnostic testing modalities. The rapid and noninvasive acquisition of this information has contributed to exponential application, and to potential overutilization. This policy addresses the medically necessary and appropriate application of TTE.
A. Ventricular Function and Cardiomyopathies
Changes in myocardial thickness (hypertrophy and thinning) in derived parameters of contractility, and in chamber volume and morphology, can be quantitated and charted over time by TTE. Cardiac responses to volume perturbations, chronic pressure excess and therapeutic interventions can be monitored. Recognition of the relative contributions of myocardial and valvular functional perturbations to a clinical presentation is facilitated. TTE aids in the recognition of myopathies and their classification into hypertrophic, dilated and restrictive types. Without clinically documented, discrete (abrupt change in signs and symptoms) episodes of deterioration, it is not generally medically necessary to repeat TTE assessments more frequently than annually, unless done to evaluate the response to therapeutic intervention.
Although TTE is used in the assessment of ventricular diastolic function, reproducible pathognomonic findings are not well established. In individuals with signs and/or symptoms suggestive of ventricular dysfunction, the demonstration by TTE of normal systolic function and/or ventricular hypertrophy may suggest the presence of diastolic functional abnormalities. Because the TTE findings suggesting diastolic dysfunction are less well established, when this application of TTE is the primary indication for the test, it will be expected to be performed by examiners recognized as experts in assessment and treatment of ventricular diastolic dysfunction.
Evaluation of diastolic filling parameters by Doppler ECHO is being used to help establish the prognosis in patients with congestive heart failure (CHF) and systolic dysfunction as well as to evaluate appropriate parameters of medical treatment.
B. Hypertensive Cardiovascular (CV) Disease
When there are no signs or symptoms of heart disease, the use of TTE is not covered for hypertension (HTN). HTN with clinical evidence of heart disease is a Medicare-covered indication for TTE evaluation. Left ventricular hypertrophy (LVH) correlates with prognosis in hypertensive CV disease. Certain anti-hypertensive medications have been reported to stabilize and possibly contribute to the regression of LVH. The decision to commit certain individuals with insidiously progressive borderline HTN to long-term anti-hypertensive therapy may be determined by the presence of LVH. TTE may assist in the decision to treat through the formulation and analysis of a treatment program. Baseline TTE and serial annual assessments may be medically appropriate. More frequent assessments should have explicit contemporaneous medical necessity documentation.
C. AMI and Coronary Insufficiency
TTE can detect ischemic and infarcted myocardium. Regional motion, systolic thickening perturbations and mural thinning can be quantitated and global functional adaptation assessed. The relative contributions of right ventricular ischemia and/or infarction can be evaluated. Complications of acute infarction (e.g., mural thrombi, papillary muscle dysfunction and rupture, septal defects, true or false aneurysm and myocardial rupture) can be diagnosed and their contribution to the overall clinical status placed in perspective. In the setting of acute infarction, repeat study will typically be dictated by the clinical course. If available, the use of contrast agents may improve diagnostic efficiency, and eliminate the need for additional radionuclide testing. Without clinical deterioration or unclear examination findings, repeat assessment is typically performed at discharge. The medical record must document the medical necessity of more frequent TTE assessments.
The role of TTE in the emergency room (ER) assessment of individuals presenting with chest pain is not defined at this time. This use is not accepted as a standard-of-care. For TTE to be allowed, clinical findings supporting myocardial dysfunction must be present. When these findings are not present, this use is not covered.
D. Exposure to Cardiotoxic Agents (chemotherapeutic and external)
Measures of myocardial contractility, thinning and dilatation are important in the titration of therapeutic agents with known myocardial toxicity. Baseline assessment, bimonthly during and at 6 months following therapy, is generally considered medically appropriate for exposure to many cardiotoxic agents. Following accidental exposure to known myocardial toxic agents, without abrupt change in clinical signs and/or symptoms, and when cardiac damage has been identified, annual assessment may be considered reasonable and necessary.
E. Cardiac Transplant and Rejection Monitoring
TTE is an integral part of the cardiac donor-selection and donor-recipient matching process. Evaluation focuses on analysis of ventricular function and valvular integrity. TTE is also incorporated into the management of allograft recipients. Myocardial thickness, refractile properties, contractile patterns and indices, restrictive hemodynamics, and the late development of pericardial fluid may alert the clinician to a rejection episode. None of these findings has achieved diagnostic sensitivity or specificity. Typically, TTE is performed weekly for the first 4-8 weeks following transplant, with decreasing frequency over time. Without acute rejection episodes, approximately 2 TTE examinations are typically performed yearly in chronic transplant recipients. TTE of cardiac allografts is appropriately performed serially at transplant centers by examiners with expertise in the management of cardiac allograft recipients. Uses in excess of the generally accepted frequency will be expected to have appropriate medical necessity documentation provided.
F. Native Valvular Heart Disease
Detection of mitral stenosis was among the first practical clinical applications of TTE. TTE is well established as the technique of choice for the evaluation of valvular pathology and its effect upon global myocardial function. The relative severity of multi-valve pathologies can be quantified. Visualization of the valve and valvular apparatus facilitates therapeutic decisions when competing therapeutic options exist, especially interventions for mitral stenosis. Absent acute intervention, or a discrete change in otherwise stable clinical signs and symptoms, TTE is used annually in follow-up of chronic valvular disease to document the course over time. Generally, it is not medically necessary to repeat these examinations more frequently than annually. When the patient’s plan of care includes imminent valvular surgery, more frequent exams may be necessary.
G. Prosthetic Heart Valves (Mechanical & Bio-prostheses)
TTE assessment soon after prosthetic valve implant is important in establishing a baseline structural and hemodynamic profile unique to the individual and the prosthesis. Size, position, underlying ventricular function and concomitant valve pathologies all impact this unique profile. Reassessment following convalescence (3-6 months) is appropriate. Thereafter, absent discretely defined clinical events or obvious change in physical examination findings, annual stability assessment is considered medically reasonable and appropriate. For certain indications, transesophageal echocardiography (TEE) may be the preferred modality for evaluation.
H. Acute Endocarditis
TEE has a high degree of sensitivity for endocarditis evaluation, and is typically the diagnostic test of choice. TTE can provide diagnostic information; larger vegetations may be directly visualized; and valvular anatomy and ventricular function directly assessed. The complications or sequelae of acute infective endocarditis can be detected and monitored over time. Acutely, examination frequency is dictated by the individual clinical course. When the acute process has been stabilized, the frequency of serial TTE evaluation will be dictated by the residual pathophysiology and discrete clinical events, analogous to the serial assessment of chronic valvular dysfunction and/or normally functioning prosthetic valves.
I. Pericardial Disease
Detection and quantitation of the amount of pericardial effusion were among the first, and remain important, applications of TTE. Pericardial fluid accumulations as small as 20 milliliters have been reliably diagnosed by TTE. Cardiac motion and blood flow patterns demonstrated by TTE characterize the hemodynamic consequences of pericardial fluid accumulation. A collage of TTE findings has been found to be a reliable indication of cardiac tamponade. TTE can be a valuable adjunct during the removal of pericardial fluid and creation of pericardial windows by balloon techniques. Acutely, clinical status will dictate examination frequency. Absent acute pathophysiology, serial assessment of chronic stable pericardial effusion by TTE is not usually medically necessary. In a patient with evolving pericardial pathology, a limited focused TTE exam may be appropriate. TTE/Doppler findings have moderate specificity and sensitivity and can be useful in the differential diagnosis of chronic pericardial constriction.
J. Aortic Pathology
TTE can provide valuable information when acute or chronic aortic pathology is present; however, the posterior window of TEE, coupled with the more posterior position of the thoracic aorta, has rendered TEE a more determinative study. Noninvasive TTE remains the study of choice for chronic aortic pathology when images suitable for serial quantitation can be obtained. Frequency of repeat study should be guided by the pathophysiology. In some individuals, such as those with Marfan’s disease or atherosclerotic aneurysms, a focused limited follow-up exam to serially measure aortic diameters and arch diameters may be appropriate.
K. Congenital Heart Disease (CHD)
In children and small adults, TTE provides accurate anatomic definition of most CHD. Coupled with Doppler hemodynamic measurements, TTE usually provides accurate diagnosis and noninvasive serial assessment. A technically adequate TTE can obviate the need for preoperative catheterization in selected individuals. When the disease process and therapy are stable, serial assessment by TTE requires medical necessity documentation, if the frequency exceeds an annual evaluation.
L. Suspected Cardiac Thrombi and Embolic Sources
TTE is sensitive in the detection of ventricular thrombi and potentially embolic material. Limited visualization of atrial interstices and the more peripheral and superior portions of the atria render TTE less sensitive than TEE in the detection of atrial thrombus and potentially embolic material. In individuals with cardiac pathology associated with a high incidence of thromboemboli (valvular heart disease, arrhythmias - especially atrial fibrillation, cardiomyopathies and ventricular dysfunction), TTE usually provides adequate supplemental data for therapeutic decision making. It merits emphasis that a negative examination (TTE or TEE) does not exclude a cardiac embolus and the findings of thrombus or vegetation does not establish a cardiac embolic source. Repeat examinations are not generally medically required in the absence of finding potentially embolic material.
M. Cardiac Tumors and Masses
Infiltrative and ventricular tumors and masses can be visualized, their extent quantitated, and their hemodynamic consequences assessed by TTE. Right atrial space-occupying masses are usually well visualized by TTE. TEE provides a more detailed view of the left atrium and is more sensitive in quantifying mass characteristics (solid, cystic, etc.), extensions and attachments. These acute pathologies are not typically followed serially. In specific situations, such as when a tumor is not removed at surgery, and when the patient has had a cardiac myxoma removed, serial TTEs may be medically necessary to monitor for tumor size or recurrence.
N. Critically Ill and Trauma Patients
There is a role for ECHO in the management of critically ill patients and trauma victims. The diagnosis of suspect aortic or central pulmonary pathology, cardiac contusion, or a pericardial effusion may be confirmed. Perturbations of volume status may be more completely defined and management strategies modified. The frequency of these typically acute studies will be dictated by the clinical situation.
O. Arrhythmias and Palpitations
TTE is useful in defining cardiac function in which arrhythmias occur, and may be useful in the management of cardiac arrhythmias. Some arrhythmias are frequently associated with underlying organic heart disease or may predispose the patient to hemodynamic deterioration. Atrial fibrillation and atrial flutter are examples of arrhythmias in which ECHO may be appropriate to assess the underlying disorder. ECHO studies are appropriate only when there is evidence of heart disease. Palpitations without clinical suspicion of arrhythmia, or evidence of heart disease, is not a covered indication for TTE.
Determination of the etiology of syncopal episodes can be a difficult clinical problem. The origin may be cardiac, neurological, or due to other causes. Syncope due to cardiac origin is most commonly related to vasodepressor reflexes, bradyarrhythmias, or tachyarrhythmias. Syncope is less commonly caused by cardiac structural disorders. Patients with structurally normal hearts generally have a much more benign prognosis than those with underlying structural coronary artery disease (CAD) or cardiomyopathic disease. ECHO is only appropriate as the initial evaluation, when other findings are suggestive of valvular heart disease or obstructive cardiomyopathy.
Right heart failure manifesting as edema or ascites may be due to pulmonary HTN. Pulmonary heart disease may result from acute changes in the pulmonary circulation (e.g., pulmonary embolus (PE)) or chronic changes produced by chronic hypoxia that may cause significant right ventricular dysfunction and hypertrophy. ECHO may assess right ventricular size and performance, and quantify the severity of pulmonary HTN using Doppler interrogation of valvular flow signals. Indications include unexplained pulmonary HTN and PE with suspected clots in the right atrium or ventricle.
R. Follow-up Studies or Limited Studies
A complete study includes a full evaluation of all aspects of the heart, including the cardiac chambers, valves, blood flow, and great vessels. The images are reviewed, measured, analyzed and interpreted by the physician. A report is prepared for the patient’s record.
S. Doppler Color Flow Velocity Mapping
Doppler color flow-velocity mapping is an appropriate addition to an ECHO when the examination is expected to contribute significant information relative to the patient’s condition or treatment plan. Typically, color flow-velocity mapping is indicated in the evaluation of the symptoms of syncope and dyspnea, some heart murmurs, valvular problems, suspected CHD, complications of myocardial infarction (MI), or cardiomyopathy. Medicare does not cover this service when performed routinely with all ECHO exams (i.e., without a clinical indication). This is true even when the results of the test reveal abnormalities. If an unsuspected finding on TTE indicates medical necessity for additional study with Doppler color flow velocity mapping, it can be covered.
T. Stress ECHO
Stress ECHO may be necessary when the evaluation could contribute significant information to the patient’s condition or treatment plan or to provide additional diagnostic information in patients with a previous non-diagnostic treadmill stress test who have signs or symptoms of suspected CAD.
Note: Stress testing (exercise tolerance testing) is not required prior to stress ECHO.
Indications and limitations for stress ECHO:
Stress ECHO is not typically performed during the acute phase of a MI when a diagnosis has been established by other methods. In selected patients, stress ECHO may be necessary when the evaluation could contribute significant information to the patient’s condition or treatment plan. Pharmacological stress is often used to provide prognostic information following MI.
2. Unstable Angina
Stress ECHO may be useful as an adjunct to other tests in the diagnosis or treatment of unstable angina only when the combination of history and other tests are not diagnostic. In selected patients, stress ECHO may be necessary when the evaluation could contribute significant information (e.g., assessment of left ventricular (LV) function) to the patient’s condition or treatment plan.
3. Chronic Ischemic Heart Disease
Stress ECHO may be useful as an adjunct to other tests in the diagnosis or treatment of chronic ischemic heart disease only when the combination of history and other tests are not contributory. In selected patients (e.g., assessment of post-coronary artery bypass grafting (CABG) symptoms for ischemia, follow-up of patients with symptomatic ischemic heart disease, or asymptomatic patients requiring follow-up that is customized to their condition and disease process) stress ECHO may be necessary when the evaluation is expected to contribute significant additional information relating to the patient’s condition or treatment plan.
Patients with conduction or repolarization abnormalities, in whom the electrocardiographic (EKG) diagnosis of stress-induced ischemia may be difficult, may require additional diagnostic information.
Patients who have a positive stress test may require stress ECHO to determine the extent and location of ischemic wall motion abnormalities.
Patients who have reduced LV ejection fraction (EF) (e.g., <45%) or CHF without an obvious other reason and when CAD cannot be ruled out, may require stress ECHO for an assessment of ischemic cause, and/or for evaluation of viability.
4. Dilated Cardiomyopathies or Hypertrophic Cardiomyopathy
Stress ECHO may be useful in the evaluation of cardiomyopathy when the evaluation could reasonably be expected to contribute significant information to the patient’s condition or treatment plan.
Stress ECHO may also be useful to assess the gradient during exercise or to assess the response to therapy initiated to limit the gradient during exercise in patients with hypertrophic cardiomyopathy and known or suspected LV outflow tract obstruction.
5. Post-Transplant Cardiac Disease
Stress ECHO may be useful in the evaluation of ventricular dysfunction with post-transplant rejection when the evaluation could reasonably be expected to contribute significant information to the patient’s condition or treatment plan and for evaluation of known or suspected post-cardiac transplant CAD.
To provide additional diagnostic information in patients with moderate CAD or known or suspected CAD who are in groups known to have a high false-positive rate for EKG changes with stress tests: (Examples are women and patients who are undergoing drug therapy which may alter the EKG response).
To observe the physiological significance of a lesion or to follow the changes after vascular intervention, before or after an acute invasive intervention.
To provide additional diagnostic information in patients with stenotic valvular heart disease (e.g., mitral stenosis and aortic stenosis) when results of a resting image or angiography are inadequate for diagnosing a valvular lesion causing symptomatic exercise intolerance.
Stress ECHO may be useful for risk stratification prior to surgery.
Pharmacological Stress Agents
For those patients who are unable to obtain 75-100% of their age-predicted maximum heart rate through physiologic exercise, vasodilation can be achieved with the use of either dipyridamole or adenosine. Dobutamine may be used to effect myocardial stress via its inotropic effect.
1. Dipyridamole is administered intravenously at 0.56 mg/kg over a 4-minute period.
The maximum dose should not exceed 70 mg. Since the dilation effect persists, its effect typically is reversed with intravenous aminophylline, which must be available to reverse ischemia when it occurs.
Dipyridamole is relatively contraindicated in patients with:
2. Adenosine is administered intravenously at 140 mcg/kg/min over 6 minutes (total of 0.84 mg/kg). The vasodilation effect of adenosine is short-lived. Adenosine is contraindicated in patients with:
Second or third degree atrioventricular (AV) block
Sinus node disease except in patients with a functioning artificial pacemaker
Known or suspected bronchoconstrictive or bronchospastic lung disease
Known hypersensitivity to adenosine
3. Dobutamine is administered intravenously starting with 5 or 10 mcg/kg/min and titrated to reach the maximum heart rate for 2-5 minutes. The maximum dose administered is up to 40 mcg/kg. Max dose is not rate dependent. Atropine may be added in appropriate doses IV. Dobutamine is contraindicated in patients with:
The use of a computer-based digitized imaging technique is required for stress ECHO interpretation.
Stress ECHO and nuclear ventriculography procedures provide similar diagnostic information. Therefore, it may not be medically necessary for both procedures to be performed on a beneficiary during the same episode of illness unless there is documentation in the medical record indicating that the results of the initial test are technically suboptimal due to reasons other than equipment problems or technician error.
Limitations of the ECHO technique may diminish its reliability in assessing myocardial disease. These limitations are particularly relevant in the following circumstances:
When a poor acoustic window precludes adequate myocardial definition and the ability to evaluate ischemia with confidence (e.g., chest wall abnormalities, severe chronic obstructive pulmonary disease or obesity);
When the sonographer does not have extensive training in the acquisition of images and in regional wall motion analysis (interpretation of stress ECHOs has a larger inter-observer variability than the interpretation of nuclear studies);
When the ECHO imaging is not done promptly after completion of exercise (regional wall abnormalities tend to resolve within the first 1 to 2 minutes after stress, especially in patients not achieving an adequate workload);
In patients with left bundle branch block (LBBB) which produces dyssynergia of the septal wall;
In patients who exhibit a hypertensive response to exercise, there may be decreased exercise-induced contractility in the absence of underlying epicardial vessel stenosis; and,
In patients with known LV hypertrophy and reduced LV end-diastolic dimensions, there may be reduced sensitivity and Dobutamine stress echo may produce suboptimal diagnostic information.
U. Physician Supervision Requirements
The technical component of TTE must be done under the general supervision of a qualified physician, appropriately trained and skilled in the performance and interpretation of ECHO. Stress ECHO is Medicare-covered only when performed under the direct supervision of a qualified physician who provides:
Medical expertise required for the performance of the test;
Medical treatment for complications and side effects of the test;
Medical services required as part of the test, for example, injections or the administration of medications;
Medical expertise in the interpretation of the test, some of which has to be provided during the test and before the patient is discharged from the testing suite.
Medicare does not cover ECHOs performed with equipment that provides limited evaluations. Such evaluations typically do not provide a permanent image and complete interpretation is not performed. These tests have demonstrated value in screening-type evaluations, although they are then considered part of the physician’s exam, similar to a BP measurement.
ECHO performed for screening purposes is not covered. Screening includes testing performed on patients who present with risk factors (including the risk factor such as having a positive family history, e.g., familial history of Marfan’s disease). Screening service for high-risk patients is considered good medical practice but is not covered by Medicare. Symptoms or an existing condition must be present to meet medical necessity.
W. Transesophageal Echocardiography (TEE)
TEE is accomplished with an ultrasound (US) generator, which can be positioned in the esophagus. TEE provides imaging information that is complementary to that obtained by TTE recording. The instrument used is a modified endoscope attached to a transducer that is capable of high-resolution 2-dimensional (2D) imaging, including color-flow, pulse-wave, and continuous-wave doppler. The TEE instrument is placed in a manner similar to the placement of a flexible esophagoscope with the same potential for serious complications. Significant esophageal pathology (e.g., tumor, stenosis, varices, diverticula) is a relative contraindication. The anticipated benefits must clearly exceed the potential risks.
The physician trained to interpret the data in real time performs the study. TEE is medically necessary under the following situations:
TTE is not technically adequate,
TTE demonstrates pathology but does not provide adequate data for clinical decision making,
TEE is expected to provide information not available with TTE or is expected to provide a better view of a structure seen on TTE, and/or
TEE is expected to contribute significant additional information useful in the patient’s management.
This policy defines the clinical pathophysiologic states for which TEE is covered based on authoritative support in the medical literature.
TEE is indicated when TTE has not provided the information required to manage the patient’s condition or when TTE is not expected to provide that information. Examples are extreme obesity, severe chronic obstructive pulmonary disease (COPD), chest deformity, incomplete visualization of the left atrium and appendage in patients with prostheses, and inadequate visualization of the atrial septum for suspected patent foramen ovale.
TTE is usually able to adequately evaluate the following conditions, although in certain specific situations TEE is also necessary:
Defining the source of embolism- Routine TEE to search for a cardiac source of embolization is not medically necessary. The key decisional factor should be whether TEE findings will substantively alter management or clinical outcome. Patients with cardiac pathology associated with an increased risk of thromboembolism may be candidates for TEE when the information obtained by the study has clinical relevance.
Native valvular heart disease- In the absence of proven or suspected endocarditis, technically adequate TTE usually suffices. TEE may be useful in the perioperative evaluation of patients who are candidates for valvuloplasty.
Prosthetic valves- TEE is not routinely indicated for follow up of patients with prosthetic valves since TTE is usually sufficient. TEE is appropriately considered when prosthetic valve dysfunction is suspected, when therapeutic decisions rest on the data obtainable, and/or when the left atrium must be visualized.
Bacterial endocarditis- TEE is considered the standard of care when the diagnosis of endocarditis is established or the index of suspicion is high, based on clinical features.
Cardiac and pericardiac masses- TEE is no better than TTE in the evaluation of right heart masses. TEE, however, provides more detail of left atrial masses and may provide additional information useful in therapeutic decisions, and therefore can be an integral part of the evaluation and management strategy.
Aortic pathology- TEE is an established tool in the diagnosis and definition of aortic dissection and aneurysm. When recurrent embolic episodes are thought to be due to aortic ulceration, atherosclerotic plaque and mural thrombotic material, and surgical intervention is contemplated, TEE may be appropriate to search for and characterize remediable aortic lesions.
Critically ill patients- When TTE fails to provide adequate visualization or is contraindicated in the critically ill or injured patient, TEE may be useful to evaluate conditions such as complications of MI, hypotension, persistent hypoxemia in patient’s with suspected right to left shunt, and patients in shock.
CHD- TEE may be appropriate to evaluate for complications of congenital heart surgery, visualization of shunt flow across atrial-septal defects, diagnosis of cor triatriatum, and detection of pulmonary valve abnormalities.
Intraoperative uses- TEE may be useful during percutaneous and open cardiac surgical interventions. TEE can provide guidance to the surgeon during the creation of shunts, repair of complex congenital defects, placement of septation devices, and performance of valvuloplasties when the surgical result cannot be adequately assessed by other means. In lung or heart-lung transplants TEE can assist in the evaluation of the integrity and structure of pulmonary vascular anastamoses.
When a surgeon specifically requests an intraoperative TEE service by the anesthesiologist, it will be determined to be reasonable and necessary only when the surgeon:
Makes a specific order/request for the anesthesiologist to perform the TEE service, and
The findings from the TEE are communicated to the operating surgeon in real-time for use during the surgery, and
The anesthesiologist makes a separate and complete written interpretation/report.
- Ventricular function monitoring- TEE monitoring of ventricular function in selected high-risk patients can complement hemodynamic monitoring data, but its routine use, even in patients undergoing cardiopulmonary bypass and valvular surgeries cannot be supported.
TEE is not medically necessary for monitoring patients having non-cardiac, non-thoracic surgical procedures. Services for the interpretation of a TEE by a properly trained physician during surgery is allowed only when the surgeon or other physician requests the services for a specific reason. A covered service must include a complete interpretation/report by the performing physician. Coverage is not allowed for monitoring, technical troubleshooting, or any other consultation that does not meet medical necessity for a diagnostic test.