Thallium Stress Tests Create Coding Confusion:
Multiple-Day Procedures Considered Single Study
Published on Fri Oct 01, 1999
Even though myocardial perfusion imaging may have several segments and extend over hours or even days, it must be assigned only a single CPT code. So says Kenneth McKusick, MD, FACR, noting that it makes no difference when components of the test are conductedmultiple, sequential-day myocardial perfusion exams are usually considered a single study.
The following explanation of the test, and its variables, clarifies why reimbursement policies recognize myocardial perfusion imaging as a single procedure.
Four CPT Codes Describe Testing Procedures
Four basic codes can be assigned during myocardial perfusion scans, says McKusick, who is retired from the Massachusetts General Hospital and now a member of the American Medical Association CPT Codes Advisory Committee, representing the Society of Nuclear Medicine. These can be categorized into two sets, he explains. Two codes can be used when two-dimensional, or planar, imaging is done, and two different codes are used when three-dimensional, or SPECT, imaging is done.
78460 : myocardial perfusion imaging; (planar) single study, at rest or stress (exercise and/or pharmacologic), with or without quantification;
78461: multiple studies (planar) at rest and/or stress (exercise and/or pharmacological), and redistribution and/or rest injection, with or without quantification;
78464: tomographic (SPECT), single study, at rest or stress (exercise and/or pharmacological), with or without quantification;
78465: tomographic (SPECT), multiple studies (planar) at rest and/or stress (exercise and/or pharmacologic), and redistribution and/or rest injection, with or without quantification.
Although there are a number of variables in the exam itself, McKusick says, the coding is quite straightforward. If both the resting and stress tests are performed, you still use either the 78461 or 78465 code, whether you separate it by just a few hours or by a full 24 hours.
He added that Medicare and insurance carriers might consider assigning a single test code twice, separated by 24 hours, to be a classic example of unbundling.
Additional Studies May Also be Billed
Medlearns book Nuclear Medicine Coder, by Jeff Majchrzak, BA, RT, NMTCB, also reports that wall motion and ejection fraction studies may be done in conjunction with the base planar or SPECT scansand billed as additional procedures.
Wall motion tests measure the movement of the left ventricle from systole to diastole. Systole refers to left ventricular contraction, when that chamber is compressed to its smallest volume, and oxygen-rich blood is circulated from the heart to the rest of the body.
Diastole refers to the second half of the circulation cycle, when re-oxygenated blood is returned to the left ventricle, by way of the lungs. Wall motion is described as normal, akinetic, dyskinetic or hypokinetic.
The CPT code for wall motion is 78478 (myocardial perfusion study with wall motion, qualitative or quantitative study [list separately in addition to code for primary myocardial perfusion imaging code procedure]).
Ejection fraction refers to the volume of blood being pumped out of the heartusually via the left ventricle. A sophisticated computer program is used to calculate this measurement, which is reported as a percentage. The appropriate code is 78480 (myocardial perfusion study with ejection fraction [list separately in addition to code for primary myocardial perfusion imaging code procedure]).
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Scans Identify Coronary Stenosis and Heart Muscle Damage
Myocardial perfusion imaging exams (often called thallium studies after the first commonly used isotope for myocardial blood flow assessment) are typically employed to assess the condition of patients with known or suspected coronary arterial blockages. In addition, they may be used to evaluate unspecified chest pain, and in the follow-up of patients who have had myocardial infarctions and/or who have undergone interventions like bypass surgery or balloon angioplasty.
According to Medlearns book Nuclear Medicine Coder, by Jeff Majchrzak, BA, RT, NMTCB, myocardial perfusion exams are ordered to differentiate between infarcted tissue (cardiac tissue that is dead and not receiving blood supply) and ischemic tissue (cardiac tissue that is only temporarily prevented from being supplied with blood).
Contrast agents like thallium and some technetium-99m compounds are introduced intravenously, and blood flow to the heart is measured. Patients may undergo either a single or a double test, explains Kenneth McKusick, MD, FACR, retired from the Massachusetts General Hospital and now a member of the American Medical Association CPT Advisory Committee, representing the Society of Nuclear Medicine. They may be tested either at rest or under stress, or they may be tested at rest and stress. In most instances, patients receive both the resting and stress exams.
During the stress portion of the test, the patient undergoes physiological stress with routine treadmill exercise, or pharmacological stress with an infusion of a vasodilator. Images of the heart are taken to determine regional blood flow. A blockage of some sort is usually clearly indicated on the scan, McKusick says.
Editors Note: According to Nuclear Medicine Coder, which presents simple explanations of nuclear medicine procedures to help coders select appropriate codes more easily, use of either mechanical or pharmacological stress requires close physician monitoring, as well as an EKG tracing. Codes from the 9301X series may be assigned for the cardiovascular stress test portion of the study in addition to the myocardial perfusion imaging.
To provide further insight into the patients condition, a resting test may then be conducted. When thallium is the contrast agent used, redistribution images will be obtained three to four hours after the initial stress images, without a second injection. However, when a technetium myocardial blood flow contrast agent is used, a second injection is infused to see if the blood supply fills in the previously blocked portions of tissue.
If a defect is discovered during exercise, but blood flow is re-established at rest, McKusick explains, the affected cardiac tissue is ischemic. This indicates a blockage that is interfering with the blood supply. If the blood does not reach the tissue even at rest, it indicates infarcted, or scarred, tissue.
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