Stroke Associated Obstruction Makes for Bottle Necked Coding
Resume the Flow with Surefire Neurointerventional Thrombolysis Coding Know-how
By David Zielske, MD, CPC, CPC-H, CCS, RCC
Strokes are the third most common cause of death in the United States, with only heart disease and cancer occurring more frequently.
A stroke, or “brain attack,” results from an interruption of normal arterial blood flow to a portion of the brain. If the flow is obstructed for an extended time, cell death and permanent damage to the affected area of the brain occurs. If the obstruction is temporary with patency re-established quickly, a transient ischemic attack (TIA) has occurred. A TIA is a warning sign that a future stroke may occur and should be taken seriously.
Don’t Dismiss the Signs of Stroke
Symptoms of strokes are varied and are not always recognized quickly. The most common are numbness, weakness, inability to move a portion of the body, garbled speech, visual field defects, or loss of balance. Less distinctive symptoms include somnolence, nausea, or just the sudden onset of headache.
Patients with heart disease and peripheral vascular disease have an increased risk for stroke, as do patients with diabetes, hypertension, and hypercoagulable syndromes.
Time is of the Essence
When a stroke is suspected, time is of the essence. The sooner definitive therapy is started, the better the results.
Several different therapies are available for stroke treatment. “Medical” treatment consists of hydration, oxygenation, and blood thinning, with or without the intravenous infusion of a blood clot dissolving drug such as tissue plasminogen activator (tPA). The use of high dose peripheral venous infusion of tPA must be started within three hours of the onset of stroke symptoms. CPT® code 37195 Thrombolysis, cerebral, by intravenous infusion describes this procedure, which is usually performed in the emergency room. It is very important to know the exact time when symptoms started, as some treatments have increased intracranial hemorrhage risk as time elapses.
If the patient is brought to a hospital specializing in acute stroke treatment, catheter directed intra-arterial instillation of thrombolytics (e.g. tPA) may be performed. The selective use of thrombolytics potentially extends the treatable time window to six hours.
Evaluation Techniques Determine Codes
Excellent neuro-interventional centers will use a team approach to evaluate the patient quickly, both clinically and with diagnostic computed tomography (CT), to determine eligibility for catheter-based therapy. When decided, the endovascular neuro-interventional specialist will perform a diagnostic angiogram to evaluate the arch, carotids, and cerebral vasculature for inflow, blockages, and clot. This procedure is coded the same as any other head and neck imaging performed in the non-acute setting, using appropriate above diaphragm catheter placement CPT® codes, 36215-36218 and imaging CPT® codes 75650 Angiography, cervicocerebral, catheter, including vessel origin, radiological supervision and interpretation, 75671 Angiography, carotid, cerebral, bilateral, radiological supervision and interpretation, 75680 Angiography, carotid, cervical, bilateral, radiological supervision and interpretation, and 75685 Angiography, vertebral, cervical, and/or intracranial, radiological supervision and interpretation, as documented.
Additional imaging of more selective intracranial vessels may be performed to evaluate potential intracranial atherosclerotic stenosis occlusions, emboli, and thrombus. If diagnostic in nature and additionally more selectively imaged, CPT® code +75774 Angiography, selective, each additional vessel studied after basic examination, radiological supervision and interpretation (List separately in addition to code for primary procedure) may be appropriate.
Code Obstruction Treatment Appropriately
If no underlying stenosis is seen, the cerebral occlusion may be the result of an embolus from the heart or elsewhere. If this is the case, the immediate concern is to treat the obstruction, either by thrombectomy, thrombolysis, or a combination of both.
Acute stroke treatment has been advanced by the development of a tiny corkscrew device that can be delivered though a microcatheter directly into the affected intracerebral artery’s clot. This is called the Mechanical Embolus Removal in Cerebral Ischemia (Merci®) retrieval device. This device is rotated and advanced into the clot, allowing removal of the offending thrombus or embolus from the brain and out of the patient through the guiding catheter. This is considered a primary arterial thrombectomy, as the intent is to remove arterial thrombus as the primary procedure. CPT® code 37184 Primary percutaneous transluminal mechanical thrombectomy, noncoronary, arterial or arterial bypass graft, including fluoroscopic guidance and intraprocedural pharmacological thrombolytic injection(s); initial vessel describes this procedure and includes imaging guidance and follow-up along with intra procedural thrombolysis. Diagnostic imaging and catheter placement is reported separately.
Should the clot extend into other branches of an intracranial artery, requiring additional thrombectomy, CPT® code 37185 Primary percutaneous transluminal mechanical thrombectomy, noncoronary, arterial or arterial bypass graft, including fluoroscopic guidance and intraprocedural pharmacological thrombolytic injection(s); second and all subsequent vessel(s) within the same vascular family (List separately in addition to code for primary mechanical thrombectomy procedure) may be used once per vascular distribution (within the same vascular family).
If the anatomy does not lend itself to this technique, intra-arterial catheter directed infusion of thrombolytic agent into the clot may be attempted. This usually consists of microcatheter placement into and through the occlusion with small aliquots of tPA infused over a fairly short time. Infusion time in the brain is usually much shorter than in the legs as there is much smaller clot volume. Unfortunately, the risk of cerebral hemorrhage from therapy is much higher in the brain than the risk of bleeding into any other part of the body. Advancing the catheter through the clot prior to tPA infusion helps to disperse the thrombolytic agent quickly and re-establish flow to the affected portion of the brain. Catheter directed thrombolysis is described with established CPT® codes 37201 Transcatheter therapy, infusion for thrombolysis other than coronary and 75896 Transcatheter therapy, infusion, any method (eg, thrombolysis other than coronary), radiological supervision and interpretation.
Follow-up angiography may be performed multiple times for intracranial work with CPT® code 75898 Angiography through existing catheter for follow-up study for transcatheter therapy, embolization or infusion, and may be coded as often as medically necessary. Should both thrombectomy and thrombolysis be used, determine if the thrombolysis is considered intraprocedural with respect to the thrombectomy and a part of the thrombectomy procedure (in which case it is bundled), or whether the thrombolysis is significantly performed before or after the thrombectomy (in which case both procedures may be billed).
If the source of the cerebral artery occlusion is not easily determined, work-up after recovery may consist of evaluation of hypercoagulable states and thrombus originating from the heart (including patent foramen oval, left atrial clot, or myxoma).
If a critical stenosis in a vessel supplying the brain is the probable cause, angioplasty or vascular stent placement may be considered at the same setting; however, it is much more likely to be performed soon after the resolution of acute symptoms. Carotid endarterectomy may be the treatment of choice depending whether a lesion in the carotid bulb appears as the cause.
Current percutaneous treatment of symptomatic severe extra or intracranial stenosis may consist of angioplasty with or without stent placement. In the intracranial vessels, CPT® codes 61630 Balloon angioplasty, intracranial (eg, atherosclerotic stenosis), percutaneous for angioplasty or 61635 Transcatheter placement of intravascular stent(s), intracranial (eg, atherosclerotic stenosis), including balloon angioplasty, if performed for stent placement are recommended. CPT® code 61635 bundles any preliminary angioplasty if performed. In the cervical carotid artery, CPT® codes 37215 Transcatheter placement of intravascular stent(s), cervical carotid artery, percutaneous; with distal embolic protection with distal embolic protection or 37216 Transcatheter placement of intravascular stent(s), cervical carotid artery, percutaneous; without distal embolic protection are used. If stents are placed in the intrathoracic common carotid or extracranial vertebral artery, CPT® codes 0075T Transcatheter placement of extracranial vertebral or intrathoracic carotid artery stent(s), including radiologic supervision and interpretation, percutaneous; initial vessel for initial or 0076T Transcatheter placement of extracranial vertebral or intrathoracic carotid artery stent(s), including radiologic supervision and interpretation, percutaneous; each additional vessel (List separately in addition to code for primary procedure) for additional vessels treated are coded. The use of these codes includes the ipsilateral imaging and catheter placements, along with guidance and follow-up imaging.
Follow Medicare Guidance for Class B-IDE Studies
For Medicare patients, intracranial angioplasty for atherosclerotic stenoses greater than 50 percent, with or without stent placement, requires enrollment in a class B-IDE study and use of unlisted CPT® code 37799 Unlisted procedure, vascular surgery to describe the procedure (instead of CPT® codes 61630 or 61635).
With technological advancements in catheter-based interventional devices, the expertise of dedicated endovascular neurointerventional surgeons, the awareness of the public concerning stroke signs and symptoms, and the critical role of timing for successful treatment, a positive impact on patient care hopefully can lessen the magnitude of this otherwise devastating disease process.