CPT® Code 61635

1. Indications

The transcatheter placement of intravascular stent(s) as described by CPT® Code 61635 is indicated for the treatment of intracranial arterial stenosis, particularly in cases of atherosclerotic stenosis. This condition is characterized by the narrowing of the arteries in the brain due to plaque buildup, which can lead to reduced blood flow and increase the risk of ischemic events such as stroke. The procedure is performed when diagnostic imaging indicates significant stenosis that may benefit from intervention to restore adequate blood flow.

• Atherosclerotic Stenosis - A condition where plaque builds up in the arteries, leading to narrowing and potential blockage of blood flow.

2. Procedure

The procedure for the transcatheter placement of intravascular stent(s) involves several critical steps to ensure successful treatment of the stenosis. Initially, the skin over the catheter access site is cleansed, and a local anesthetic is administered to minimize discomfort during the procedure. A small stab incision is made in the skin, allowing for the insertion of a needle into the blood vessel, followed by the placement of a sheath to facilitate access. A microcatheter or neurointerventional guidewire is then threaded from the access artery into the carotid circulation, allowing for navigation to the intracranial arteries.

• Step 1: The intracranial artery requiring treatment is selectively catheterized by advancing an arteriography catheter over the guide catheter wire. This step is crucial for performing diagnostic arteriography, which evaluates the anatomy of the artery and determines whether balloon angioplasty is necessary.
• Step 2: If balloon angioplasty is indicated, additional angiograms are obtained to assess the stenotic artery and to select the appropriate size and placement of the angioplasty balloon. The angioplasty balloon catheter is then prepared for use.
• Step 3: A steerable micro-guidewire and microcatheter are advanced through the guide catheter into the intracranial arteries, crossing the stenosed artery. The micro-guidewire is then removed and replaced with an exchange wire, allowing for the advancement of the angioplasty balloon catheter over the exchange wire to the stenotic region.
• Step 4: The balloon is inflated to dilate the stenotic region under fluoroscopic control. Once adequate dilation is achieved, the balloon catheter is withdrawn into the access artery, but not removed, while the guidewire remains in place.
• Step 5: Post-procedure angiograms are obtained to evaluate for hyperacute thrombosis or rebound stenosis, and additional interventional measures are initiated if these conditions occur.
• Step 6: Following the successful dilation of the stenotic lesion and addressing any complications, the catheters and guidewires are removed.
• Step 7: In the case of CPT® Code 61635, an intracranial intravascular stent is placed. If indicated, balloon angioplasty is performed as previously described. The stent delivery system is advanced over the exchange wire or catheter until it is positioned across the area of stenosis.
• Step 8: The stent is deployed, and the delivery system is withdrawn into the access artery, leaving the exchange catheter or wire in place. Angiograms are obtained to evaluate the position of the stent, and after a 15-minute interval, additional angiograms are performed to rule out complications.
• Step 9: Finally, all catheters and wires are removed, completing the procedure.

3. Post-Procedure

After the completion of the transcatheter placement of intravascular stent(s), patients are typically monitored for any immediate complications, such as hyperacute thrombosis or rebound stenosis, through follow-up angiograms. The recovery process may involve observation in a clinical setting to ensure that the patient is stable and that the stent is functioning as intended. Patients may be advised on post-procedure care, including monitoring for any signs of complications and following up with their healthcare provider for further evaluation and management. The overall goal of the post-procedure phase is to ensure the successful restoration of blood flow and to minimize the risk of future ischemic events.