NIA Magellan Coverage Policy
Electron Beam Tomography (EBCT)
CPT Codes: 75571, S8092
Indications for CAC Testing
(Greenland 2018; Hecht 2017; Blankstein 2017; Pender 2016; Goff 2014; Nasir 2015; McClelland 2015; Piepoli 2016; Mahabadi 2017; Gerber 2018)
- In the context of shared decision making among patients aged 40 to 75 years who are free of clinical atherosclerotic cardiovascular disease and deemed to be at intermediate-to-low or intermediate risk (5 - 20%), and adjusting that risk up or down based upon the CAC score has been documented in the record as necessary to adjust cardiovascular risk management, such as decisions with respect to statin therapy (Stone 2013; Michos 2017; Hecht 2017; Wilkins 2018).
- Patients who are over 75 or younger than 40 are far less likely to have meaningful alteration in risk, but CAC testing can be considered in these patients when there is strong, well-documented evidence that the result of CAC testing could alter management, in the context of documented patient-physician shared decision making (Tota-Maharaj 2012).
- Patients with estimated 10-year risk of less than 5%, but are suspected to be at elevated atherosclerotic cardiovascular disease (ASCVD) risk because of a major risk factor not accounted for in the global risk equations, such as erectile dysfunction, rheumatologic diseases (lupus, psoriasis, ankylosing spondylitis, or rheumatoid arthritis), or family history of premature CAD (Greenland 2018; Michos 2017; Hecht 2017).
- Patients in whom statin therapy is indicated but who have intolerable adverse effects from statins or reluctance to take statin medication, to guide the need for alternative lipid-lowering strategies (Nasir 2015; Michos 2017; Blankstein 2017).
- Repeat CAC testing may be repeated for risk re-assessment after a minimum of 5 years, if documentation indicates it will alter management (e.g. prior CAC = 0), which should be rare in patients who already have a prior CAC score > 0 (Michos 2017; Greenland 2018; Hecht 2017). It should not be repeated if the patient has already had two CAC Scores of zero 5 years apart (Greenland 2018).
CPT Codes: 75572, 75573
|| Often required
||Required for some tissue characterization studies, often unnecessary
||None, advantage for young patients and those requiring frequent exams
||Moderate to High
Some scenarios might provide more detail with low dose CT than with CMR, thereby overriding the radiation risk (Ohana 2015, Schoenhagen 2005).
INDICATIONS FOR HEART CT
(Taylor 201; Douglas 2011)
Evaluation of Cardiac Structure and Function
(Warnes 2008; Wiant 2009; Baumgartner 2010; Orwat 2014; Kilner 2010)
Adult Congenital Heart Disease
- For evaluation of anomalous thoracic arteriovenous vessels, such as TGA, when MRI cannot be performed (Cohen 2016; Warnes 2008).
- Further assessment of complex adult congenital heart disease after confirmation by transthoracic echocardiography (TTE), but TTE was inadequate for clinical management (consider advantages of CMR below).
- When TTE and/or transesophageal echocardiography (TEE) has been or would be insufficient for clinical management, for the choice between CMR and CT, several aspects must be considered including radiation exposure, resolution required, sum of information required, its impact upon management, the presence of a pacemaker/implantable cardioverter defibrillator (ICD) or other implants, and patient claustrophobia. Sample indications include:
- Quantification of RV volumes and ejection fraction (tetralogy of Fallot, systemic RV, and tricuspid regurgitation) [CMR better than CT, if available] (Haddad 2008, Dupont 2009, Benza 2008).
- Evaluation of the RV outflow tract and RV-PA conduits (CMR or CT).
- Evaluation of the entire aorta (aneurysm, dissection, intramural hematoma, Loeys-Dietz,
- Ehlers-Danlos, or confirmed genetic mutation known to predispose to aortic aneurysm and dissection. CMR or CT initially, with annual CMR (MRI) for Loeys-Dietz, Ehlers Danlos; multiple options for Marfan’s, Turner’s (see Aortic Pathology section below) (Hiratzka 2010).
- Evaluation of pulmonary arteries (stenosis and aneurysms) and the aorta (coarctation) (CMR or CT).
- Evaluation of systemic and pulmonary veins (anomalous connection, obstruction, etc) (CMR or CT).
- Aorto-pulmonary collaterals and arteriovenous malformations (either, but CT is superior to CMR for spatial resolution, if needed).
- Coronary anomalies and CAD (indication for CCTA, better than CMR).
- Quantification of myocardial (muscle) mass (CMR or CT).
- Assessment of right ventricular morphology in arrhythmogenic right ventricular dysplasia/cardiomyopathy, based upon reason for suspicion, of which examples are:
- Nonsustained VT
- ECG abnormality: Prolonged S wave upstroke, epsilon waves, or right precordial T wave inversions (> 14 yr old) in the absence of complete RBBB
- First degree relative with phenotype or genotype of ARVD/C (either, but CMR is superior to CT) (Marcus 2010; McKenna 2018; te Riele 2015).
Left Ventricular Function Assessment
- Evaluation of left ventricular function following acute MI or in HF patients, when echocardiography (even with contrast) and radionuclide angiography/ventriculography are inadequate (Fihn 2012; Patel 2013).
- Characterization of native or prosthetic valves with clinical signs or symptoms suggesting valve dysfunction, when TTE, TEE, and fluoroscopy have been inadequate (e.g. bioprosthetic valve thrombus post transcatheter or surgical valve replacement) (Doherty 2017).
- Evaluation of the calcium score of the aortic valve in symptomatic patients with severe calcific aortic stenosis by calculated valve area (≤ 1.0 square cm), low flow (stroke volume ≤ 35mL/square M) with low gradient (mean < 40 mm Hg or Doppler < 4 M/sec), and ejection fraction < 50%, when low dose dobutamine shows no flow (contractile) reserve (failure to increase stroke volume > 20%), to assist with the determination of the severity of the aortic stenosis. Severe (in Aggatston units): >1,200 women, >2,000 men) (Baumgartner 2017; Steiner 2017; Clavel 2017).
- Evaluation of the calcium score of the aortic valve in symptomatic patients with severe calcific aortic stenosis by calculated valve area (≤ 1.0 square cm), low flow (stroke volume ≤ 35 ml/square M) with low gradient (< 40 mm Hg or Doppler < 4 M/sec), and preserved ejection fraction ≥ 50%, to assist with the determination of the severity of the aortic stenosis. Severe (in Aggatston units): >1,200 women, >2,000 men) (Baumgartner 2017; Clavel 2017)
- Evaluation of the calcium score of the aortic valve in symptomatic patients with severe calcific aortic stenosis by calculated valve area (≤ 1.0 square cm and index ≤ 0.6 square cm/square M), normal flow (stroke volume ≥ 35 mL/square M) with low gradient (mean < 40 mm Hg or Doppler < 4 M/sec), and preserved ejection fraction ≥ 50%, to assist with the determination of the severity of the aortic stenosis. Severe (in Aggatston units): >1,200 women, >2,000 men) (Clavel 2017).
- Evaluation of RV systolic function, including systolic and diastolic volumes, in severe tricuspid TR, when TTE images are inadequate and CMR is not readily available
- Evaluation of suspected infective endocarditis with moderate to high pretest probability (i.e. staph bacteremia, fungemia, prosthetic heart valve, or intracardiac device), when TTE and TEE have been inadequate.
- Evaluate morphology/anatomy in the setting of suspected paravalular infections when the anatomy cannot be clearly delineated by TTE and TTE (Nishimura 2014).
- Patients with bicuspid aortic valve and aortic dilation > 4.0 cm require annual imaging with CT, MRI, or echo. Echo is required when it can evaluate the full extent of pathology under surveillance. This would increase to biannual (twice-yearly) imaging in the event of any one of the additional conditions: diameter > 4.5 cm, rapid rate of change 0.5 cm/yr, or a family history of a first degree relative with aortic dissection. Initial imaging with first 6 month re-evaluation for rate of expansion is appropriate.
Evaluation of Intra- and Extracardiac Structures
- Evaluation of cardiac mass (suspected tumor or thrombus, including valvular mass or vegetation), when imaging with TTE and TEE have been inadequate (consider advantage of CMR for superior tissue characterization). (Doherty 2017; Kassop 2014; Baumgartner 2017; Nishimura 2014; Sexton 2018)
- Evaluation of pericardial anatomy, when TTE and/or TEE are inadequate or for better tissue characterization of a mass and detection of metastasis, if malignancy is suspected (CMR superior for physiologic assessment (constrictive versus restrictive) and tissue characterization, CT superior for calcium assessment) (Klein 2013; Pennell 2010).
Electrophysiologic Procedure Planning
- Evaluation of pulmonary venous anatomy prior to radiofrequency ablation of atrial fibrillation and for follow up when needed for evaluation of pulmonary vein stenosis (Waiee, 2012; Ohana, 2015; Niinuma 2008; Schoenhagen 2010; Raijah 2013).
- Non-invasive coronary vein mapping prior to placement of biventricular pacing leads (Raijah 2013; Van de Veire 2006; Heydari 2012)
Transcatheter Structural Intervention Planning
- Assessment of the aortic annular dimensions, aortic root, and aortic valve, in planning for transcatheter aortic valve replacement (TAVR) (Otto 2017; Raijah, 2013; Schoenhagen 2010; Doherty 2017).
- When TTE and TTE cannot provide adequate imaging, CT imaging can be used for planning: robotic mitral valve repair, atrial septal defect closure, left atrial appendage closure, ventricular septal defect closure, endovascular grafts, and percutaneous pulmonic valve implantation (Raijah 2013; Schoenhagen 2010; Flachskampf 2014; Pison 2015).
- Evaluation for suitability of TMVR, transcatheter mitral annuloplasty, and transcatheter mitral PVML closure, alone or in addition to TEE (Wunderlich 2018).
(Hiratzka 2010; Erbel 2014; Schiller 2017; Wright a&b 2018; Woo a&b 2018; Svensson 2013; Doherty 2017; Nishimura 2014; Baumgartner 2014; Hendel 2006; Bhave 2018)
Echo is required when it can evaluate the full extent of pathology under surveillance.
- CT, MR, or echo can be used for screening and follow up, with CT and MR preferred for imaging beyond the proximal ascending thoracic aorta.
- Screening first degree relatives of individuals with a history of thoracic aortic aneurysm (defined as > 50% above top normal) or dissection or an associated high risk mutation for thoracic aneurysm in common.
- Screening second degree relative of a patient with thoracic aortic aneurysm (defined as > 50% above top normal), when the first degree relative has aortic dilation, aneurysm, or dissection.
- Six month follow up after initial finding of a dilated thoracic aorta, for assessment of rate of change.
- Annual follow up of enlarged thoracic aorta that is above top normal for age, gender, and size up to 4.4 cm.
- Biannual (twice/yr) follow up of enlarged aortic root > 4.5 cm (> 4.5 cm for bicuspid aortic valve) or showing growth rate > 0.5 cm/year.
- Marfan’s patients require annual imaging with CT, MRI (avoids radiation, especially, when frequent evaluation required), or echo when it can evaluate the full extent of pathology, with increase to biannual (twice-yearly) when diameter > 4.5 cm or when expansions is > 0.5 cm /yr (complete aortic annual CMR is recommended for Loeys-Dietz, Ehlers-Danlos, and certain other noted genetic mutations, wherein surgical intervention is recommended as at low as 4.2 cm).
- Turner’s syndrome patients should undergo imaging (CT, MRI - avoids radiation, especially when frequent evaluation required, or echo (when it can evaluate the full extent of pathology), of the heart and aorta for evidence of dilatation of the ascending thoracic aorta, and with normal imaging and no risk factors for aortic dissection, repeat imaging should be performed every 5-10 years, or if otherwise indicated. If the aorta is enlarged, appropriate follow up imaging should be done according to size, as above. With a bicuspid aortic valve, the recommendation below applies.
- Patients with bicuspid aortic valve and aortic dilation > 4.0 cm require annual imaging with CT, MRI, or echo. (Echo is required when is can evaluate the full extent of pathology under surveillance.) This would increase to biannual (twice-yearly) imaging in the event of any one of the additional conditions: diameter > 4.5 cm, rapid rate of change 0.5 cm/yr, or a family history of a first degree relative with aortic dissection. Initial imaging with first 6 month reevaluation for rate of expansion is appropriate.
- Any interval increase > 3 mm on echo should be validated by CT or CMR (Baumgartner 2014).
- When higher resolution measurement is required for determining an indication for surgery, CT appears slightly better (Baumgartner 2014).
- Computed tomographic imaging or magnetic resonance imaging of the thoracic aorta is reasonable after a Type A or B aortic dissection or after prophylactic repair of the aortic root/ascending aorta.
- Computed tomographic imaging or magnetic resonance imaging of the aorta is reasonable at 1, 3, 6, and 12 months post un-operated dissection, penetrating atherosclerotic aortic ulcer, and, if stable, annually thereafter, so that any threatening enlargement can be detected in a timely fashion.
- Postoperative surveillance recommendations are taken from the 2010 ACC Thoracic Aortic Disease Guideline (Hiratzka 2010).
(Taylor 2010; Schoenhagen 2005; Raijah 2013)
Scenarios for which approval of Heart CT is generally not approvable:
- For same imaging tests less than six weeks apart unless specific guideline criteria states otherwise.
- For different imaging tests, such as CT and MRI, of same anatomical structure less than six weeks apart without high level review to evaluate for medical necessity.
- For re-imaging of repeat or poor quality studies.
- This study remains the best test for initially examining children in the assessment of congenital heart disease. However, if findings are unclear or need confirmation, CMR or CT can be useful.
CT and CMR in Congenital Heart Disease (CHD)
- Many more children with congenital heart disease (CHD) are surviving to adulthood, increasing the need for specialized care and sophisticated imaging. Currently more adults than children have CHD. CT and CMR provide 3D anatomic relationship of the blood vessels and chest wall, and depict cardiovascular anatomic structures. (Warnes 2008; Wiant 2009).
CT and Cardiac Masses
- CT and CMR are used to evaluate cardiac masses, describing their size, density, tissue characteristics, and spatial relationship to adjacent structures. Nearly all cardiac tumors are metastases. Primary tumors of the heart are rare, and most are benign. Cardiac myxoma is the most common type of primary heart tumor in adults and usually develops in the left atrium. Echocardiography is typically the first method for evaluation of cardiac myxoma. CT and CMR can provide adjunctive information on myxomas when necessary (Kassop 2014).
CT and Pericardial Disease
- While echocardiography is most often used in the initial examination of pericardial disease, CT and CMR can evaluate pericardial thickening and masses which are often detected initially with echocardiography. CT and CMR can accurately define the site and extent of masses, e.g., cysts, hematomas and neoplasms (Klein 2013).
CT and Radiofrequency Ablation for Atrial Fibrillation
- Atrial fibrillation, an arrhythmia triggered by abnormal electrical activity in the pulmonary veins, is the most common supraventricular arrhythmia in the United States. In patients with atrial fibrillation, radiofrequency ablation is used to electrically disconnect the pulmonary veins from the left atrium. Prior to this procedure, CT or CMR is useful to define the pulmonary venous anatomy encountered during the procedure. Determination of how many pulmonary veins are present and their ostial locations is important to make sure that all the ostia are ablated. Post ablation pulmonary vein stenosis can also be diagnosed with CT and CMR. The higher resolution detail of CT might make it preferable over CMR in some cases (Ohana 2015).
CTA Coronary Arteries (CCTA)
CPT Codes: 75574
The Three Types of Chest Pain or Discomfort
- Typical Angina (Definite) is defined as including all 3 characteristics:
- Substernal chest pain or discomfort with characteristic quality and duration
- Provoked by exertion or emotional stress
- Relieved by rest and/or nitroglycerin
- Atypical Angina (Probable) has only 2 of the above characteristics
- Nonanginal Chest Pain/Discomfort has only 0 -1 of the above characteristics
- Once the type of chest pain has been established from the medical record, the Pretest Probability of significant CAD is estimated from the Diamond Forrester Table below, recognizing that additional coronary risk factors could increase pretest probability (Wolk 2013):
||Typical/Definite Angina Pectoris
||Atypical/Probable Angina Pectoris
||Nonanginal Chest Pain
| ≤ 39
| ≥ 60
- Very low: < 5% pretest probability of CAD, usually not requiring stress evaluation (Fihn 2012)
- Low: 5-10% pretest probability of CAD
- Intermediate: 10% - 90% pretest probability of CAD
- High: > 90% pretest probability of CAD
Indications for CCTA
(Gerber & Manning 2018; Fihn 2012; Montalescot 2013; Wolk 2010; Taylor 2010)
- Evaluation in suspected CAD (Douglas 2015; Newby 2015; Nicol 2008; Fordyce 2016; Moss 2017):
- Intermediate pretest probability patients who are not suitable for stress echo (see Additional Information section)
- Low pretest probability patients who are not suitable for either exercise stress ECG (uninterpretable) or stress echo (see Additional Information section)
- Appropriate exercise electrocardiogram (ECG) stress test with low Duke Score (> 5) and continued symptoms that are concerning for CAD, usually typical or atypical angina
- Appropriate exercise ECG stress test with intermediate (negative 10 to +4) Duke Score.
- Equivocal, borderline, discordant, or inconclusive prior stress imaging evaluation, including discordant exercise ECG and stress imaging
- Repeat non-invasive coronary testing in patient with new or worse symptoms since prior normal stress imaging (Wolk 2013; Taylor 2010)
- Newly diagnosed clinical systolic heart failure without known CAD or current CAD evaluation, in the presence of angina or an anginal equivalent (Patel 2012; Patel 2013; Wolk 2013; Taylor 2010)
- Reduced left ventricular ejection fraction (<40% EF), when invasive coronary arteriography is not the preferred method of evaluation
- An alternative to coronary angiography before valve surgery or transcatheter intervention in patients with severe valvular heart disease (VHD) and low or intermediate pretest probability of CAD or in whom conventional coronary angiography is technically not feasible or associated with a high risk (Baumgartner 2017; Nishimura 2014)
- Unable to undergo otherwise appropriate non-invasive coronary evaluation with any of the following: exercise ECG, myocardial perfusion imaging (MPI), and stress echocardiography (SE) (Douglas 2015; Newby 2015; Nicol 2008; Fordyce 2016)
- To establish the etiology of chronic secondary mitral regurgitation (Nishimura 2014)
- Evaluation of coronary anomaly or aneurysm (e.g. post Kawasaki’s disease) when CMR is not available (Datta 2005; Newburger 2016; Newburger 2018; Grani 2017)
- For evaluation of coronary artery bypass grafts, to assess (Eisenberg 2017):
- Patency and location, when invasive coronary arteriography was unable to acquire adequate images
- Patency, if it might avoid invasive coronary arteriography
- Coronary bypass graft location when reoperative cardiac or other chest surgery requires
Unsuitability for Stress Echo (Askew 2018; Henzlova 2016):
- Poor Quality Echo Image
- Obesity with BMI over 40 or poor acoustic imaging window
- Inability to Exercise
- Physical infirmities precluding a reasonable ability to exercise for at least 3 full minutes of Bruce protocol
- The patient has limited functional capacity (< 4 METS) such as one of the following:
- Cannot take care of their activities of daily living (ADLs) or ambulate
- Cannot walk 2 blocks on level ground
- Cannot climb 1 flight of stairs
- Cannot vacuum, dust, do dishes, sweep, or carry a small grocery bag
- Patients who cannot walk up a single flight of stairs at even a slow pace or even perform ADLs based upon documented limitations
- Comorbidity Related
- Prior cardiac surgery (coronary artery bypass graft or valvular), CHF with left ventricular ejection fraction < 40%
- Severe chronic obstructive pulmonary disease (COPD) with pulmonary function test (PFT) documentation, severe shortness of breath on minimal exertion, or requirement of home oxygen during the day
- Poorly controlled hypertension, with systolic blood pressure (BP) > 180 or Diastolic BP > 120
- Medical instability or serious acute illness, where maximal exercise is not recommended or appropriate (e.g. acute myocarditis or pericarditis, active infective endocarditis, acute aortic dissection)
- Resting wall motion abnormalities that would make exercise stress echocardiography (SE) interpretation difficult, which includes left bundle branch block (LBBB)
- More than moderate valvular heart disease, when coronary data, not valvular hemodynamics, are required
- ECG Related Uninterpretable Wall Motion
- Pacemaker or implantable cardioverter defibrillator (ICD)
- Poorly controlled atrial fibrillation/ectopy
- Frequent premature ventricular contractions (PVCs)
- Ventricular pre-excitation (e.g. Wolff Parkinson White)
- Complete LBBB (SE doable, but more difficult to interpret)
- Risk Related
- High pretest probability in suspected CAD
- Intermediate or high global risk in patients requiring type IC antiarrhythmic drugs
- Patients with prior coronary revascularization
- Arrhythmia risk with exercise and provocation of arrhythmia not required for test
- Left ventricular ejection fraction < 40%
Unsuitability for MPI (Henzlova 2016; Chareonthaitawee 2018):
- Patient cannot be adequately positioned or imaged with MPI due to comorbidity, body habitus
- Intolerance to required coronary vasodilators, pulmonary or allergic, either documented or anticipated.
- Uncontrolled hypertension, systolic > 200 or diastolic > 110
- Dipyridamole within < 48 hours
- Relative unsuitability due to:
- Hypotension or marked bradyarrhythmia
- Interfering medications: Theophylline/aminophylline, caffeine, or theobromine within the past 12-24 hours
- Severe aortic stenosis
- Seizure disorder with potential for adenosine provocation
Coronary Artery Calcium Scoring (Gerber & Kramer 2018):
Non-contrast coronary computed tomography (non-contrast coronary CT) and its older technological version, electron beam computed tomography (EBCT), provide quantitative coronary artery calcium scoring, which is appropriate for further evaluation of coronary risk in asymptomatic patients without known cardiovascular disease, who are at low to intermediate or intermediate global risk for coronary or overall cardiovascular disease. Non-contrast coronary CT (computed tomography) and EBCT are supported by a separate CPT code and guideline document with references titled EBCT or Non-Contrast Coronary CT.
Definitions of Coronary Artery Disease (Fihn 2012; Montalescot 2013; Patel 2017; Mintz 2016; Tobis 2007)
- Percentage stenosis refers to the reduction in diameter stenosis when angiography is the method and refers to cross sectional narrowing when intravascular ultrasound (IVUS) is the method of determination.
- Coronary artery calcification is a marker of risk, as measured by Agatston score on coronary artery calcium imaging. It is not a diagnostic tool so much as it is a risk stratification tool. Its incorporation into global risk can be achieved by using the MESA risk calculator.
- Stenoses > 50% are considered obstructive coronary artery disease (also referred to as clinically significant), while stenoses < 50% are considered nonobstructive coronary artery disease (Gerber & Manning 2018).
- Ischemia-producing disease (also called hemodynamically or functionally significant disease, for which revascularization might be appropriate) generally implies at least one of the following:
- Suggested by percentage diameter stenosis > 70% by angiography; borderline lesions are 40-70% (Fihn 2012; Tobis 2007)
- For a left main artery, suggested by a percentage stenosis > 50% or minimum lumen cross sectional area on IVUS < 6 square mm (Fihn 2012; Mintz 2016)
- FFR (fractional flow reserve) < 0.80 for a major vessel (Mintz 2016)
- Demonstrable ischemic findings on stress testing (ECG or stress imaging), that are at least mild in degree
- A major vessel would be a coronary vessel that would typically be substantial enough for revascularization, if it were indicated. Lesser forms of coronary artery disease would be labeled as “limited” and not major (i.e. a 50% lesion in a tiny septal or modest size mid PDA would be limited obstructive coronary artery disease).
- Microvascular ischemic coronary artery disease, as might be described by a normal FFR (fractional flow reserve) above 0.80 with a reduced CFR (coronary flow reserve less than 2.5), has not otherwise been addressed in this manuscript, because it is very rarely an issue in compliance determinations. However, it would constitute a form of ischemic heart disease.
- FFR is the distal to proximal pressure ratio across a coronary lesion during maximal hyperemia induced by either intravenous or intracoronary adenosine. Less than or equal to 0.80 is considered a significant reduction in coronary flow. Newer iterations such as iFR (instantaneous wave free ratio) might supersede basic FFR technology in the near future.
- New technology is evolving that estimates FFR from CCTA images. This is covered under the separate NIA Guideline for FFR-CT.
Anginal Equivalent (Moya 2009; Shen 2017; Fihn 2012):
Development of an anginal equivalent (e.g. shortness of breath, fatigue, or weakness) either with or without prior coronary revascularization should be based upon the documentation of reasons to suspect that symptoms other than chest discomfort are not due to other organ systems (e.g. dyspnea due to lung disease, fatigue due to anemia), by presentation of clinical data such as respiratory rate, oximetry, lung exam, etc. (as well as d-dimer, chest CT(A), and/or PFTs, when appropriate), and then incorporated into the evaluation of coronary artery disease as would chest discomfort. Syncope per se is not an anginal equivalent.
Fractional Flow Reserve CT
CPT Codes: 0501T, 0502T, 0503T, 0504T
INDICATIONS FOR FFR-CT
(Douglas 2016; Norgaard 2015; Hulten 2015; Hulten 2017; Maroules 2017)
- In a patient for whom ICA is under consideration, based upon results of clinical evaluation and/or non-invasive testing, both criteria #1 and #2 below should be met: (Douglas 2016; Norgaard 2017; Hulten 2017)
- Immediately before CCTA, the patient was stable with a pre-test probability between 20% and 80% of obstructive (> 50%) coronary artery disease, based upon a reliable calculator (updated Diamond Forrester, ESC Consortium, University of Washington, or similar calculators, for which links are provided in the Additional Information section) (Fihn 2012).
- The medical record presents at least one of the following scenarios:
- Patient has a pretest probability of 20-50% (low-to-moderate) prior to CCTA and was selected for evaluation with CCTA as a non-invasive test for significant coronary artery disease. The CCTA result shows lesions of 40-80% OR
- Patient had a pretest probability of 51-70% (moderate or high moderate) prior to CCTA and was selected for evaluation with CCTA as a non-invasive test for significant coronary artery disease. The CCTA result shows lesions of 30-70%.
- Lesions which could realistically fall into the above ranges, with the stipulation that calcification has made percentage stenosis interpretation difficult, could support approval of FFR-CT, in conjunction with the above criteria (Norgaard 2015).
Inapplicable Scenarios for FFR-CT
(Douglas 2016; Pontone 2015)
None of the following clinical scenarios below apply since FFR-CT either
- Has not been adequately validated due to inapplicability of computational dynamics OR
- Due to problematic artifacts, and/or clinical circumstances.
When such patients have artifacts (heavy calcium) or body habitus (BMI > 35) that could interfere with the examination, the suitability for FFR-CT is at the discretion of the vendor who provides the FFR-CT service.
- Suspicion of an acute coronary syndrome, unless the patient has unstable angina, myocardial infarction was excluded, and ICA would not be recommended if FFR-CT were negative
- Known ischemic coronary artery disease that has not been revascularized, and there has been no change in patient status or in the CCTA images
- Recent myocardial infarction within 30 days (Gaur 2017)
- Prior coronary artery bypass graft surgery
- Patients who require emergent or urgent ICA or have any evidence of ongoing or active clinical instability, including acute chest pain (sudden onset), cardiogenic shock, unstable blood pressure with systolic blood pressure <90 mmHg, severe congestive heart failure (New York Heart Association (NYHA) III or IV) or acute pulmonary edema
- Complex congenital heart disease or ventricular septal defect (VSD) with pulmonary-tosystemic flow ratio > 1.4
- BMI > 35 (can be done at discretion of vendor)
- Metallic stents in the coronary system
- Coronary vessels with extensive or heavy calcification (can be done at discretion of vendor)
- Coronary lesions needing evaluation in which vessel diameter < 1.8 mm
- Cardiac Implanted Electrical Devices (CIEDs)
- Prosthetic Heart Valves
- Severe wall motion abnormality on CCTA results
- Severe myocardial hypertrophy
- High risk indicators on stress test
- ICA within the past 90 days
- Marginal quality of the submitted imaging data, due to motion, blooming, misalignment, arrhythmia, etc.
Effort to reduce unnecessary invasive coronary arteriography (ICA): Since traditional FFR measurement has been performed in conjunction with invasive coronary arteriography (ICA), FFR-CT has been developed with the intention of noninvasively adding hemodynamic information to the anatomic findings on CCTA, with the purpose of safely reducing the frequency of unnecessary ICA procedures, (defined as all ICA lesions < 50%). Such a reduction in ICA by FFR-CT has been suggested, but not rigorously proven, by the clinical trials to date. Its use appears appropriate for stable patients without known CAD (Koo 2011; Min 2011; Norgaard 2014; Douglas 2015a; Douglas 2016; Labounty 2015; Norgaard 2017; Hulten 2016; Hulten 2017). An economic analysis suggested that FFR-CT could reduce cost and improve upon quality of life for some patients (Hlatky 2015), but this might not be an improvement over CCTA alone (Hulten 2016).
Current Methodology: The analysis requires a CCTA scanner with at least a 64-slice capability and good-quality images. At present, the process involves transmitting the CCTA data to an offsite location, where a digital model of coronary anatomy is constructed, and using the CCTA data, FFR is calculated using the above described computational fluid dynamics. In this fashion, a report of estimated FFR for the vessels in question is generated, with the intention of reporting coronary hemodynamic information to the requesting clinician (Hulten 2017).
I. FFR-CT Results:
The working assumption is that quantitative estimation of coronary lesional hemodynamic severity using FFR-CT might enable deferral of invasive coronary arteriography when values are above 0.80, since such lesions would not warrant revascularization. Although FFR-CT measurements appear reproducible (Gaur 2014), there remains concern regarding the accuracy of FFR-CT relative to invasive FFR (Hulten 2015). Aside from excellent reproducibility (Johnson 2015), invasive FFR has a demonstrated track record of favorable outcomes when used in the selection of patients and vessels worthy of PCI (Tonino 2009; De Bruyne 2014; Van Nunen 2015; Xaplanteris 2018).
While evidence suggests that FFR-CT might be a better predictor of revascularization or adverse events than severe stenosis alone on CCTA (Lu 2016), the FFR-CT data to date provide no evidence showing that revascularization based upon FFR-CT improves outcomes over invasive angiographic assessment. As a consequence of the above considerations, current revascularization guidelines do not advocate FFR-CT as a surrogate for invasive FFR, although, those guidelines refer to FFR-CT as an “emerging technology” (Patel 2017).
More recently publication of a study on the use of FFR-CT to derive a functional SYNTAX Score in multivessel CAD demonstrated a fair correlation with invasive iFR (instantaneous flow reserve, a reliable variation of FFR). With respect to detection of functionally significant lesions identified on invasive FFR (<=0.80), FFR-CT showed good sensitivity (95%) and negative predictive value (87%), but weak specificity (61%) and positive predictive value (81%), area under the receiver operator curve (ROC) of 0.85. This suggests a possible future role for this technology (Collet 2018).
About this Guideline
Because of the lack of long term outcomes data and flaws in the design of multiple trials, and given the controversy evidenced by numerous editorials and review articles in peer reviewed journals, there is a lack of a formal guideline from any professional society at this time. While endorsed by the British health care system, details are lacking for UM purposes (Groves 2017).
Based upon findings in the important PLATFORM trial, for patients who are evaluated initially by noninvasive stress testing, without yet being considered for ICA, CCTA with contingent FFR-CT could be perceived as actually having a similar or higher rate of unnecessary ICA. In addition, PLATFORM did not study the question of whether FFR-CT adds to CCTA alone in preventing “unnecessary’ invasive coronary angiography (Hulten 2017; Dewey 2016), although there is some evidence that it might (Lu 2016). In the absence of randomized trials, numerous considerations were based upon a diverse body of literature, in the interest of formulating this de novo guideline (Packard 2016; Min 2017; Hulten 2013; Hulten 2015; Hulten 2016; Hulten 2017).
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