CPT and ICD-9 Coding for Endograft Repair of AAA

sicians unfamiliar with CT. As yet there is no consensus on the optimum degree of device oversizing.

Change in Aneurysm Morphology with Time This results in disarticulation of modular devices and limb kinking. Solutions include use of one piece devices, which have a higher incidence of limb kinking, and thus secondary stent placement. Modular devices are being designed with longer overlaps at the articulation points, and increased friction between the components at their overlap points. Fabric Weal' This results from continuous pulsation of the graft against the stent, particularly at points of kinKing or with endoleaks. All manufacturers with the fabric outside the stent claim not to have encountered fabric wear to date (although suture rupture has been seen), thus at present this appears to be a device specific problem. Longer term data is .required. Endoleaks Improvements in stent graft design and deployment have not been successful in reducing the incidence of type II endoleaks, which occur in up to 43.9% of patients at discharge and 29.8% at one month after endovascular stent grafting (8). Type II endoleaks have been described in the literature to transmit systemic blood pressure to the aneurysm sac (9), be associated with continued aneurysm expansion (10), and have been implicated in delayed aneurysm rupture (11). Despite this, there is no consistent opinion among manufacturers as to whether this is a problem requiring a remedy, let alone developing solutions. O·eation of a Chmnic ''Problem'' Open surgery is a finite treatment and the patient usually has limited contact with his vascular therapist after the procedure. Insertion of an endograft requires eternal follow-up at least at 6-month intervals. A significant problem has been the organization of this follow-up by the vascular surgeon.

References 1. Moore WS, Rutherford RB, for the EVf Investigators. Transfemoral endovascular repair of abdominal aortic aneurysm: results of the North American EVT phase 1 trial. J Vasc Surg 1996; 23:543-553. 2. Lloyd WE, Paty PSK, Darling RC, et al. Results of 1000 consecutive elective abdominal aortic repairs. Cardiovasc Surg 1996; 4:724-726. 3. Chuter TAM, Wendt G, Hopkinson BR, et al. European experience with a system for bifurcated stent graft insertion. J Endovasc Surg 1997; 4:13-22. 4. May J, White GH, Yu W, et al. Concurrent comparison of endoluminal vs open repair in the treatment of abdominal aortic aneurysms: analysis of 303 pa-

tients by life table method.J Vasc Surg 1998; 26:519523. 5. Armon MP, Yusuf W, Latief K, et al. Anatomical SUitability of abdominal aortic aneurysms for endovascular repair. Br J Surg 1997; 84:178-180. 6. Blum U, Voshage G, Lammer J et al. Endoluminal stent grafts for infrarenaI abdominal aortic aneurysms. N Eng! J Med 1997; 336:13-20. 7. Wolf YG, Fogarty TJ, Olcott Cet al. Endovascular repair of abdominal aortic aneurysm: Eligibility rate and impact on the rate of open repair. J Vasc Surg 2000; 32:519-523. 8. Karch LA, Henretta JP, Hodgson KJ, et al. Algorithm for the Diagnosis and Treatment of Endoleaks. Am J Surg 1999; 178:225-231. 9. Baum RA, Carpenter JP, Tuite CM, et al. Diagnosis and Treatment of Inferior Mesenteric Arterial Endoleaks after Endovascular Repair of Abdominal Aortic Aneulysms. Radiology 2000;215:409-413. 10. Katzen BT. The GuidantlEVf Ancure Device. ]VIR Suppl 2000; 11:62-66. 11. Politz JK, lewman VS, Stewart MT. Late abdominal aortic aneurysm rupture after AneuRx repair: A report of three cases. J Vasc Surg 2000; 31:599-606.

3:35 p.m. CPT and ICD-9 Coding for Endograft Repair of AAA Robert L. Vogelzang, MD Northwestern Medical Center Chicago, Illinois Arteries and Veins ~ Endovascular

Repair ofAbdominal Aortic Aneurysm 34800-34826 describe placement of an endovascular graft for abdominal aortic aneurysm repair under fluoroscopic guidance and include vascular access, all catheter manipulations, balloon angioplasty within the endovascular prosthesis (for full expansion of the endoprosthesis) and closure of the arteriotomy site. Extensive repair or replacement of an artelY should be additionally reported (eg, 35226 or 35286). ~ For fluoroscopic guidance in conjunction with endovascular aneurysm repair, see code 75952 or 75953, as appropriate. Code 75952 includes angiography of the aorta and its branches for diagnostic imaging prior to deployment of the endovascular device (including all routine components of modular devices), fluoroscopic guidance in the delivery of the endovascular components, and intraprocedural arterial angiography (eg, confirm pOSition, detect endoleak, evaluate runoff). Code 75953 includes the analogous services for placement of additional extension prostheses (not for routine components of modular devices). ~ Other interventional procedures performed at the ~ Codes

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time of endovascular abdominal aortic aneurysm repair should be additionally reported (eg, aortography before deployment of endoprosthesis, renal transluminal angioplasty, arterial embolization, intravascular ultrasound, balloon angioplasty of native artery(s) outside the graft (eg, aortic or iliac) before deploymem of endoprosthe~ sis). • 34800 Endovascular repair of infrarenal abdominal aortic aneurysm or dissection; using aono-aortic tube prosthesis • 34802 using modular bifurcated prosthesis (one docking limb) • 34804 using unibody bifurcated prosthesis • 34808 Endovascular placement of iliac artery occlusion device (List separately in addition 10 code for primary procedure) ~ (Use 34808 in conjunction with codes 34800, 34813, 34825, 34826) ~(For radiological supervision and interpretation, use '75952 in conjunction with 34800, 34802, 34804, 34808) ~ (For open approach, report codes 34812-34820 in addition to codes 34800, 34802, 34804, 34808 as appropriate) • 34812 Open femoral artery exposure for delivery of aortic endovascular prosthesis, by groin incision, unilateral ~(For bilateral procedure, use modifier '·50') • +34813 Placement of femoral-femoral prosthetic graft during endovascular aortic-aneurysm repair (List sep3i"d.tely in addition to code for primary procedure) .. (Use 34813 in conjunction with code 34812) • (For femoral artery grafting, see 35521, 35533, 35546,35551-35558,35566,35621,35646,35651-35661, 35666, 35700) • 34820 Open iliac artery exposure for delivery of endovascular prosthesis or iliac occlusion during endovascular therapy, by abdominal or rerroperi.1Oneal incision; unilateral • "(For bilateral procedure, use modifier '-50') • 34825 Placement of proximal or distal extension prostheSiS for endovascular repair of infra renal abdominal aortic aneurysm; inirial vessel • 34826 each additional vessel (List separately in addition to code for primary procedure) • (Use 34826 in conjunction with code 34825) • (Use code 34825, 34826 in addition to codes 34800-34808, as appropriate) .. (For staged procedure, use modifier '-58') ~(For radiological supervision and interpretation, use 75953) • 34830 Open repair of infrarenal aortic aneurysm or dissection, plus repair of associated arterial trauma, follOWing unsuccessful endovascular repair; tube prosthesis • 34831 aorto-bi-iliac prosthesis • 34832 aorto-bifemoral prosthesis

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Rationale Prior to CPT 2001, no codes existed to accurately describe a new treatment option in the repair of abdominal aortic aneurysms (A.A._i\.) using minimally invasive procedures for implantation of an endovascular graft. To accurately delineate the procedural differences associated with abdominal aneurysm repair techniques/technology, a new subsection heading, introductory notes and twelve new CPT codes have been added. Codes 34800~ 34832 describe the various multi-procedural techniques reqUired to place a new and different delivery system via fluoroscopic guidance. Endovascular graft placement is a new treatment option for patients with AAA. The current treatment for AAA is open surgical repair using a direct transabdominal or retroperitoneal approach La the external surface of the aneurysm. The endovascular approach utilizes less invasive techniques as opposed to a large abdominal incision. \Vith endovascular repair, a collapsed prosthesis is introduced through arteries in the groin, and then advanced into pOSition within the aneul)'sm using fluoroscopic guidance. Once in exactly the correct location the prosthesis is expanded to full.size. This approach eliminates the need for a large abdominal or retroperitoneal incision to expose the aneurysm. Although the intended outcome of these two methods is the same, endovascular AAA repair requires different skills and resources (eg, catheters, endovascular grafts, complex catheter manipulation using high quality fluoroscopic guidance). The existing codes for direct AAA repair (ie, 35081-direct repair aneurysm abdominal aorta, and 35102-direct repair aneul)'sm abdominal aorta involving iliac vessels) do not reflect the approach or techniques involved in endovascular graft placement. Existing CPT codes for traditional aneurysm repair involve a large abdominal or retroperitoneal incision, surgical exposure of the aneurysm, and temporary occlusion of blood flow with large vascular hemostats prOXimal and distal to the aneul)'sm. The aneul)'sm is opened longitudinally, a tubular prosthesis is placed within the open sac, and the ends of the prosthesis are sutured to normal portions of the aorta at each end of the aneurysm. Blood flow is restored, hemostasis achieved, and The l:uge incision is closed. Repair of an aortic aneurysm using an endovascular approach is entirely different. For endovascular repair of an aneurysm the prosthetic graft material may be similar to that used in open repair, but the method of attachment differs. With open repair, the prosthesis is sutured to the proximal and distal artery. With endovascular repair the prosthesis is anchored above and below the aneurysm with a variety of metal frameworks and/or attachment devices. Anesthesia for endovascular AAA repair may be general or epidural. The procedure is performed in a specially-equipped suite, either an interventional radiology room SUitably eqUipped for open surgery, or an opei"d.ling room eqUipped with high quality fluoroscopy with angiographic capability.

Incision Incision ______

Femoral artery

Femoral vein ----tr~~>t_;+_f_

..:.tl,.-#--'I-\----- Com mol' iliac artery i-Hl,\:-T-----\,.:--.•.- - - - Ureler __ ~_

~

internal iliac anGry

Figure 1. Illustration of CPT Code 34812: Open femoral artery exposure for delivery of endovascular prosthesis, by groin incision;' unilateral.

The introductory notes of this new subsection have been added to clarify those procedures that are considered inclusive for placement of the endovascular prosthesis. and those procedures that require additional reporting. You will note that in this new series there are two open surgical approach codes. Depending upon the exposure technique required, the surgical approach may be reported by the same or different physician performing placement of the endovascular prosthesis.

Rationale: Endogmjt Coding The aortic endograft procedure begins after placement of appropriate guidewire catheters perform used to the "roadmapping" aortogram prior to deployment of the endoprosthesis (see following for clarification as to when it is appropriate to report code 36200 versus 75952). Similar to aU intelventional vascular procedures, access to the target attety is achieved by advancing a guidewire from the access site to the target site. For endovascular AAA repair, this means manipulating the guidewire from the femoral artery through the external and common iliac arteries, and into the aorta. The guidewire must then be advanced through the aneurysm (avoiding dislodgment of intraluminal thrombus) to a position above the renal artery origins. The guidewire serves as the means over which the endovascular device sheaths are subsequently advanced into pOSition. Most endovascular AAA systems reqUire aortic catheter access from both groins. Some procedures entail selective catheter placement in a renal artery for absolute identification in order to avoid covering the renal origin with the prosthesis. When performed, code 36245 is used to code the catheter placement in the renal artery from the contralateral side. Code 36200 is used for the contralateral side if the catheter is placed non-selectively in the aorta for identification of the renal arteries and for

Figure 2. Illustration of CPT Code 34820: Open artelY exposure for delivery of endovascular prosthesis, or iliac occlusion during endovascular therapy, by abdominal or retroperitoneal incision; unilateral

guidewires access for the contralateral side. An angiogram performed for final confirmation of the anatomy is used as a "roadmap" for the remainder of the procedure, and is included with the radiologic S&I code 75952.

Ratiolutle: Surgicttl Approach Several of the cu rrent prostheses are constructed in modular components so that the delivery "system" is com· prised of the primary prosthesis plus one or two "docking limbs", each in individual sheaths. A compressed prosthesis is preloaded within a special delivery sheath. The delivery sheaths are introduced through unilateral or bilateral arteriotomies in the common femoral or external iliac arteries and reported by codes 34800-34804, as appropriate. Since the delivery sheaths may be qUite large, open surgical exposure of one (34812) or both groins (3481250) may be required to ensure safe entry and closure. The descriptor of code 34812 delineates that the procedure is "unilateral." If "bilateral" femoral or iliac arteriotomies are required, code 34812 should be reported with the modifier -50 appended. Code 34812 includes vascular control of branches to expose a site on the artery through which catheters, gUidewires, and the endovascular prosthetiC components are delivered. Code 34812 includes the routine surgical closure of the arteriotomy and the overlying soft tissue. Code 34812 does not include repair, replacement, extensive endarterectomy of the femoral artery, or maneuvers that are occasionally necessary after removal or the very large introducer sheaths employed for placement of endovascular prostheses. P303

UOibody bifurcalod p'.... "'esis

J..,l.,.Il---\--- Aorto~aortic rube prothesis

Abdominal aortic aneurysm - - - - - - - \ - -

Figure 4. Illustration of CPT Code 34804: unibody bifurcated prosd1esis.

Figure 3. Illustration of CPT Code 34800: aorta-aortic tube prosthesis.

When the iliac or femoral aneries are diseased or of inadequate cliameter to allow passage of the large endovascular introducer sheaths, open surgical exposure of the iliac or femoral artery(s) may be required. Code 34820 is a unilateral procedure that describes a retroperitoneal or abdominal incision (typically through a skin incision in the flank) for surgical exposure for arteriotomy in a segment of the iliac/femoral artery, where the diameter is suitable for entry of guidewires and introducer sheaths. For bilateral open surgical exposure, code 34820 should be reported with the modifier -50 appended. Rationale: Radiologic Guidance (also see Radiology) Entry of the endovascular prosthesis within the arterial system to the exact position requires fluoroscopic guidance. Two new radiology codes have been established for fluoroscopic guidance in conjunction with endovascular aneurysm repair (75952 and 75953, see Radiology). Rather than using direct visualization for positioning the prosthesis, as done in open repair, positioning of the endograft is accomplished with high resolution fluoroscopic and angiographic control. Code 75952 is reported in addition to endovascular graft procedures, codes 34800-34808, as appropriate. Code 75953 is reported in addition to the endovascular extension prostheses procedures, codes 34825 and/or 34826, as appropriate. Rationale: Endovascular Aneurysm Repair Code 34800 describes placement of an endovascular tube graft. This type of graft is used less frequently than the bifurcated grafts (34802), because only a minority of patients has suitable anatomy. Placement of the entire

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prosthesis is accomplished from a single groin, but the requirement for accurate positioning often means that guidewires and catheters are passed from both sides. Code 34802 describes placement of a bifurcated aortic endograft, used for those patients having an aneurysm that extends to the very distal aorta or into the proximal common iliac arteries. In this circumstance, the absence of an adequate normal distal portion of aorta to serve as a "landing zone" for a tube prosthesis (34800) precludes use of such a device. The bifurcated endograft systems require iliac limbs of appropriate length to allow hemostatic seal in relatively normal portions of the common iliac artery. Several of the bifurcated systems accomplish this exact iliac limb length requirement by employing a modular design wherein the main aortic prosthesis has one very short iliac limb. In order to complete the aneurysm repair, this type of device or iliac "docking limb" is advanced over the guidewires and inserted into the short limbs of the main prosthesis. Note: Code 34802 involves a unilateral limb modular device. A coding change proposal for establishment of a new category III code describing placement of a device with two modular limbs is currently under review through the CPT process for CPT 2002. Code 34804 describes placement of a unibody or "single piece" bifurcated endoprosthesis. The graft is specifically tailored to the exact dimensions required for the individual patient. Similar to the placement technique described by code 34802, in order to extend the contralateral iliac limb appropriately into the iliac artery, the limb must be cannulated from the contralateral groin which involves several complex steps. When that is accomplished, the contralateral limb is extended and seated. Note: Balloon angioplasty within the body of the endovascular aortic prosthesis is typically performed

J L --t

Aboomtl'\CII,!".o~nic,--_ _

aneurysm

Iliac artery occlusion

' L - - - - - - d.~c.

Femoral-femora! pfOSlhetic graft

Figure 5. Illustration of CPT Codes 34808/34813: iliac artery occlusion device and femoral-femoral prosthetic graft.

j

L K·O..:.ll---- proximal BKtenslonpfOlhesis

'.-rr--+--- Bifuttatedp:othesis

Figure 6. Illustration of CPT Codes 34825/34826: proximal and d.istal extension prosthesis (initial vessel) and each additional vessel.

with a compliant balloon to promote full expansion of the endoprosthesis and complete contact of the attachment devices. These maneuvers are included in the main endovascular AAA repair codes 34800-34804. Codes 35452 (open aortic transluminal angioplasty) and 35472 (percutaneous aortic transluminal angioplasty) should not be additionally reported, as these codes would be considered components of the new procedure. However, balloon angioplasty performed concurrently, but outside the body of the endoprosthesis comprises a separate and distinct service that would be coded separately. Code 34808 describes iliac artery occlusion accomplished by placing an endovascular occlusion device. Depending upon the type of endograft required and the occlusive disease invlolved, if the contralateral iliac artery is not patent, the artery must be "occluded" to prevent retrograde blood flow into the aneurysm sac. Therefore, blood flow to that contralateral leg must be

restored with a femoral-femoral crossover bypass graft (code 34813). Code 34813 is a new add-on code that describes placement of a femoral-femoral crossover graft procedure. Once the iliac occlusion device is in place, blood flow to the contralateral leg is restored with the femoralfemoral crossover graft. Since dissection of both femoral arteries is required to perform the femoral-femoral crossover, code 34812 should be additionally reported with the modifier -50 appended.

Rationale: Endovascular Extensions Occasionally, an aortic endograft may not be quite long enough either at the proximal or distal end, and completion angiography will demonstrate an endoleak. Placement of proximal or distal extensions is described by code 34825 for the initial vessel and code 34826 for each additional vessel. Most often, placement of endovascular extensions will be performed during the same session as performance of the aortic endoprosthesis. However, on occasion an endoleak will be discovered early or late postoperatively. In this event, code(s) 34825 for the initial vessel and code 34826 for each additional vessel should be reported. If endovascular extension placement is performed in the postoperative period of the original procedure, the modifier -78 should be appended. Note: Codes 34825 and 34826 may also be reported if an extension is required at the time of the original endovascular repair to fully cover the lesion. The code is used once per vessel and not per cuff/extension. "Extensions" are sections of endograft designed for one end to lie within the existing endoprosthesis and for the other end to protrude either more proximally in the aorta or more distally in the i1iacs. The extensions are designed in various diameters and lengths to accomplish successful treatment of the aneurysm or sealing of the endoleak; and are placed over the existing guidewires from the ipsilateral or contralateral groin. Accurate position is accomplished with careful fluoroscopic guidance to avoid occlusion of important aortic or iliac branches such as the renal or hypogastric arteries. Code 75953 should be reported in addition to code(s) 34825, 34826. Once in the exact location, the extension is deployed similar to placement of the iliac docking limbs. The ext nsions may also be "tacked" in place by inflation of a compliant balloon (see note above). Should extensive repair or replacement of an artery be required, this procedure should be additionally reported (eg, 35226 or 35286). Rationale: Open MA, Subsequent to Endovascular Repair Codes 34830-34832 describe open surgical conversion procedures involving a previously-placed endoprosthesis. Complications associated with endoluminal grafts differ from those encountered during open repair. They include endoleaks (persistent blood flow between the P305

prosthesis and the wall of the aneurysm), dissection, occlusion of major arterial branches such as renal arteries, and acute occlusion of aortic or iliac flow. Some of these complications may require urgent or emergent open surgical aneurysm repair. In this circumstance, codes 34830-34832 should be reported (as opposed to the open aneUiysm repair codes), since the conversion to an open repair following an unsuccessful endovascu· lar approach is substantially more complex than primary elective direct repair (codes 35082 or 35102). Codes 35082 or 35103 also do not accurately describe the conversion procedure, as those codes describe treatment of "ruptured" aortic aneurysm. The typical patient requiring the procedures described by 34830-34832 is likely to be rar more ill postoperatively than the patient who undergoes elective, traditional open repair. In addition, the operative procedure itself is likely to be longer, more involved, and more complex due to prior manipulation of catheters, possible need to extract pieces of endograft, etc.

Rationale: Reporting of Other [nteroentional Procedures

Other interventional procedures performed at the time of endovascular abdominal aortic aneurysm repair should be additionally reported (eg, renal transluminal angioplasty, arterial embolization, intravascular ultrasound, balloon angioplasty of native artery(s) outside the graft (eg, aortic or iliac) before or after deployment of endoprosthesis. Occasionally concurrent interventional procedures are performed at the time of the endovascular AAA repair. These should be coded in addition to the new codes for AAA repair by endovascular techniques. They include: renal PTA and/or stent placement to treat a renal arcery stenosis; embolization of one or more large lumbar, inferior mesenteric or hypogastric arteries felt to place the patient at risk for subsequent endovasclliar leak; intravascular ultrasound (NUS) to confirm device sizing, correct placement of th~ graft, or to confirm placement of the contralateral limb within the docking port before deployment. Intravascular ultrasound may also be used to evaluate within the graff for persistent deformity or incomplete opening after ballooning; • balloon angioplasty of the native iliac arteries required before deployment of the aonic prosthesis to allow passage fo the large delivery system through markedly diseased and stenotic alteries; stent placement within the aortic or iliac portions of the endograft to treat kinks or endoleaks; Occasionally, concurrent open surgical procedures are performed at the, time of the endovascular AAA repair. These should be coded in addition to the codes for routine AAA repair by endovascular techniques. They include:

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• Extensive repair or replacement of femoral or external iliac artery at the arteriotomy site. Note: On rare occasion, the femoral and external iliac arteries are injured due (0 manipulation of the very large delivery systems used for endovascular AAA repair. When extensive repair or replacement of an artelY is required after removal of the delivery sheath, one of the existing arterial repair codes (code 35226 or 35286) would be reported in addition (0 the new surgical exposure code 34812, since the work involved in repair is substantially different than that involved in the typical exposure and arteriotomy closure; Femora-popliteal bypass or femoro-tibial bypass performed concomitantly for arterial occlusive disease. Clinical Example (34800) A 67-year-old male with chronic obstructive pulmonary disease and coronary artery disease, status post myocardial infarction has a 5.8 cm aortic aneurysm. lmaging studies indicate that the aneurysm is infrarenal with an adequate neck (0 allow successful deployment of an endovascular prosthesis. There is also adequate normal aorta below the aneurysm to allow use of a tube graft. The iliac artery anatomy should accommodate passage of the device. Descripfion ofProcedure (34800) The device and typically large introducer are threaded onto the gUidewire and adv!'lnced to the edge of the artery. An arteriotomy is fashioned and the introducer is pushed into the artery. The device is then carefully advanced through the iliac arteries, into the aorta, and positioned such that the proXimal edge is just below the renal artery origins and above the beginning of the aneUiysm. Its posicion is confirmed exactly by fluoroscopy, often with injections of contrast. lf a selective second catheter has been placed to mark the lower renal allery, it is drawn back into the iliac, and the main endovascular device is deployed under exacting fluoroscopic guidance. Fine adjustments in position are made during the deployment to assure accurate positioning just below the renal artery origins. In some patients the mean arterial pressure is transiently reduced by the anesthesiologist to decrease the chance that pressure from flOWing blood will push the endograft distally during deployment. After deployment, the arterial pressure is normalized. The introducer portion of the main device is removed over the guidewire, leaving the endograft in position. Some devices require balloon dilatalion at the proximal and distal anastomoses to help assure proper seating and hemostatic seal with the arterial wall. Jf this is the case, a large diameter compliant balloon is advanced over the wire to the proXimal anaswmosis, and under fluoroscopic guidance the balloon is positioned and inflated. This same balloon may be pulled back and used to seat the distal anastomosis.

Once the complete endograft is in place, a pigtail catheter or multi-sidehole catheter is repositioned over one of the guidewires, and placed just above the renal arteries for a final angiographic evaluation. An aortogra!TI is performed and immediately evaluated for graft position, patency of appropriate branches (renals and hypogastrics), presence or absence of endoleaks, and patency of lumbar or inferior mesenteric arteries that may contribute to persistent endoleaks. Removal of the catheters and guidewires is performed. Alteriotomy site and skjn closure is also performed. Clinical Example (34802) A 67-year-old male with chronic obstructive pulmonary disease and coronary artery disease, status post myocardial infarction, has a 5.8 cm. aortic aneurysm. Imaging studies indicate that the aneurysm is infrarenal in nature with an adequate neck of normal aorta below the renal artery origins for deployment of an endovascular prosthesis. Distally the aneurysm extends to the end of the aorta, indicating that a bifurcated prosthesis will be required. Iliac arteries are of appropriate diameter and length to provide landing zones for the iliac limbs of the prosthesis. The iliac artery anatomy should accommodate passage of the device. Description ofProcedure (34802) The procedure begins by loading the endovascular device and its introduction mechanism onto the guidewire and advancing it to the edge of the artery. A large arteriotomy is made, and the introducer is pushed in. This large introducer sheath often fills the entire lumen of the femoral artery. The device is carefully advanced through the iliac arteries and positioned such that the proximal edge is just below the renal artery origins and above the beginning of the aneurysm. Its position is confirmed ex~ctly by fluoroscopy, often with injections of contrast. If a selective second catheter has been placed to mark the lower renal artery, it is drawn back into the iliac, and the main endovascular device is deployed under exacting fluoroscopic gUidance. Fine adjustments in position are made during the deployment to assure accurate positioning just below the renal artery origins. In some patients the mean arterial pressure is transiently reduced by the anesthesiologist to decrease the chance that pressure from flOWing blood will push the endograft distally during deployment. After deployment the arterial pressure is normalized. The introducer portion of the main device is removed over the gUidewire, leaving the endograft in pOSition. Some devices reqUire balloon dilatation at the proXimal and distal anastomoses to help assure proper seating and hemostatic seal with the arterial wall (not a separately billable service). If this is the case, a large diameter compliant balloon is advanced over the wire to the proXimal anastomosis, and under fluoroscopic guidance the balloon is positioned and inflated. This same balloon may be pulled back and used to seat the iliac anastomosis by

using an incomplete inflation (since the iliac diameter is smaller than the aorta). In other cases, a balloon better matched to the iliac diameter is required, entailing an exchange of balloons over the guidewire. The guidewire on this initial ipsilateral side is left in position within the endograft, and attention is turned to the contralateral side for placement of the docking limb. The gUidewire on this side has been left in position within the iliac artery. Using fluoroscopic guidance, this guidewire is advanced into the docking port of the short itiac limb of the main prosthesis. This frequently is a difficult and timeconsuming maneuver, since the aneurysm may be large and may divert the catheter or gUidewire away from the intended target. If it is not possible to pass the wire from the contralateral groin into the appropriate position, access may be obtained by using the catheter from the ipsilateral groin. With appropriate manipulation this may be hooked over the flow divider of the aortic prosthesis, allowing passage of the guidewire down the short contralateral iliac limb, through the docking port, and down the native contralateral iliac artery. This guidewire may then be grasped by passing a snare device upward from the contralateral groin and pulling the guidewire out through the arteriotomy. Having achieved this "over the horn" guidewire configuration, a catheter is passed back up the wire, into the contralateral limb docking port, and past the flow divider. If this maneuver is used, the selective catheter code for the ipSilateral side is changed from 36200 for placement of the catheter into the aorta to 36245 for first order selective catheterization of the contralateral common iliac artery. If this maneuver is unsuccessful, the contralateral port may also be accessed by means of an axillary or brachial artery puncture. If an ann approach is used, a third access code would also be reported in addition to the one or two femoral catheterization codes. (In this case, code 36245 would probably be the appropriate code, for first order selective catheterization of the contralateral common itiac artery). Trus allows passage of a guidewire from above, maneuvering it into the contralateral port, and then snaring the wire from the contralateral groin. Once a gUidewire has been successfully advanced from the contralateral groin into the contralateral docking port of the aortic prosthesis, the contralateral docking limb is placed. A sheath is usually passed over the wire. The contralateral limb is advanced through the sheath into docking position, and the exact position of the limb is determined by fluoroscopy. The proximal end must be firmly seated within the docking port of the main prosthesis while the distal end must be located within a normal diameter segment of iliac artery, usually proximal to the iliac bifurcation. Once correct position is confirmed, the sheath is pulled back, and the limb is deployed. Accurate deployment is checked with fluoroscopy, using contrast injection. For some devices, the proximal and distal ends of this iliac limb are secured in

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position and fully opened by dilation using appropriately sized balloons. Once the complete endograft is in place, a pigtail catheter or multisidehole catheter is repositioned over one of the guidewires, and placed just above the renal arteries for a final angiographic evaluation. An aortogram is perfonned and immediately evaluated for graft position, patency of appropriate branches (renab and hypogastrics), presence or absence of endoleaks, and patency of lumbar or inferior mesenteric arteries that may contribute to persistent endoleaks. If the graft is in good position and free of endoleaks, the intra-service portion of 34802 is complete. Removal of the catheters and guidewires is included in the catheter inU'oduction codes (36200-36248) and the arteriotomy and skin closure is included in 34812-34820.

Clinical Example (34804) A 67-year-old male with chronic obstructive pulmonal)' disease and coronal)' artery disease, status post myocardial infarction, has a 5.8 em. infrarenal aortic aneurysm. Imaging studies indicate th:;ll the aneurysm is infra renal with an adequate neck to allow successful deployment of an endovascular prosthesis. Distally the aneurysm extends to the end of the aorta, indicating lhat a bifurcated prosthesis will be required. Iliac arteries are of appropriate diameter and length to provide landing zones for the iliac limbs of the prosthesis. The iliac artery anatomy should accommodate passage of the device. Description of Procedure (34804) This procedure commences when the endovascular device and its introducing mechanism are brought onto the surgical field. Deployment of a unibody bifurcated prosthesis differs from the modular design in that the first steps include passage of the special contralateral iliac limb guidewire into the aorta and capture of this wire by a snare advanced through the arteries from the opposite groin. Once completed, this technically demanding step allows the contralateral graft limb to be pulled downward from the aOfla into that opposite iliac artery. Once this step is completed, the delivery sheath is loaded onto the guidewire and advanced to the edge of the femoral artery. This sheath is very large in diameter and typically requires incision of up to half of the arterial circumference to allow entry. The device is advanced slowly through the femoral and iliac arteries into the aorta. ]t is carefully positioned such that the proximal edge is just below the renal artery origins and above the beginning of the aneurysm. Exact position is confirmed by fluoroscopy, using injections of contrast. ]f a selective second catheter has been placed to mark the lower renal artery, it is drawn back into the iliac, and the main endovasclilar device is deployed under fluoroscopic guidance. Fine adjustments in position are made during the deployment to assure accurate positioning just below the renal artery origins. Tn some patients the mean arterial pressure is transiently reduced by the anesthesiolo-

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gist to decrease the chance that pressure from flOWing blood will push the endograft dislally during deployment. After deployment the arterial pressure is normalized. The introducer portion of the main device is removed over the guidewire, leaving the endograft in position. Some devices require balloon dilatation at the aortic and iliac attachment sites lo help assure proper seating and hemostatic seal. Tf this is' the case, a large diameter compliant balloon is advanced over the wire to the proximal anastomosis, and under fluoroscopic guidance the balloon is pOSitioned and inflated. This same balloon may be pulled back and llsed to seat the iliac anastomosis by using an incomplete inflation (since the iliac diameter is smaller than the aorta). ]n other cases, a balloon better matched to the Uiac diameter is required, entailing an exchange of balloons over the guidewire. The next step is deployment of the contralateral iliac limb. The leading guidewire for this limb has already been snared and exits the opposite femoral artery. This wire is carefully retracted, leading the second iliac limb across the aortic bifurcation into the appropriate common iliac artery. Further manipulations are done to bring the contralateral limb into correct position, and then this limb is deployed. This second iliac limb is typically

dilated with a compliant balloon (all balloon dilations within the body of the device are included in the work of

this code). When the complete endograft is in place, a pigtail catheter or multisidehole catheter is repositioned over one of the gllidewires, and placed just above the renal arteries for a final angiographic evaluation. An aortagram is performed and immediately evaluated for graft position, patency of appropriate branches (renals and hypogastrics), presence or absence of endoleaks, and patency of lumbar or inferior mesenteric arteries that may contribute to persistent endoleaks. If the graft is in good position and free of endoleaks, the intra-service portion of 34802 is complete. Removal of the catheters and guidewires is included in the catheter introduction codes (36200-36248) and the arteriotomy and skin closure is included in the femoral artery exposure codes 34812-34820.

Clin.ical Example (34808) A 67~year-old male with chronic obstructive pulmonary disease and coronary artery disease, statu-s post myocardial infarction, has a 5.8 cm. infra renal aortic aneurysm. Imaging studies indicate an adequate proximal aortic neck to allow deployment of an endovascular prosthesis. Distally there is an appropriate landing zone in the aorta to allow placement of a tube graft. The right iliac artery anatomy will accommodale passage of the main device. However, there is diffuse, severe arterial occlusive disease involving the entire left common and external iliac artery. Thus, it has been decided that the left common iliac will be occluded using endovascular technique, and a right-to-Ief( femoral-femoral bypass graft will be placed to reperfuse the left leg.

Description oj Procedure (34808) Placement of the iliac occluder device and its introducer onto the guidewire is performed. The device is then advanced under fluoroscopic guidance to the exact location where the occlusion is to be performed. Fine adjustments under fluoroscopic guidance are made as necessary. The device is deployed and appropriate position is confirmed by hand injection of contrast. If required to achieve complete arterial occlusion, additional embolization materials may be placed, and this work is included within the work description of this code. The device introducer is removed. Clinical Example (34812) A 67-year-old male with chronic obstructive pulmonary disease and coronary artery disease, status post myocardial infarction, has a 5.8 em. infrarenal aortic aneurysm. Imaging studies indicate an adequate proximal aortic neck to allow deployment of an endovas0ular prosthesis. Distally there is an appropriate landing zone in the aorta to allow placement of a tube graft. The right iliac altery anatomy will accommodate passage of the main device. Description oj Procedure (34812) skin incision is made in the inguinal region. The subcutaneous tissue is dissected until the common femoral artery is located. Care is taken to avoid injury to the femoral nerve and vein that lie in close proximity. The comIIl.on, superficial, and deep femoral arteries are dissected and captured in vessel loops. The distal external iliac artery is typically included in the dissection. This exposure is accomplished by retraction and/or division of the inguinal ligament. The extra exposure facilitates introduction of the very large diameter sheath required for endovascular AAA repair. It also serves to apply countertraction and temporarily reduce tortuosity of the iliac alteries as the sheath is advanced. Hemostasis in the groin is achieved by ligation or electrocautery of small branch arteries and veins. Intravenous heparin is administered before the arteries are clamped. A transverse arteriotomy is made in the anterior surface of the common femoral or distal-most external iliac artery for introduction of the guidewires and sheaths. Intra-service work of 34812 resumes after deployment of the device has been completed and all sheaths and guidewires have been removed. The arteriotomy is dosed with very fine (eg, 6-0 polypropylene) sutures. Hemostasis is achieved, the wound is irrigated, and the soft tissue is reapproximated in several layers. Skin closure is performed with staples or sutures. A

Clinical Example (34813) A 67-year-old male with chronic obstructive pulmonary

disease and coronary artery disease, status post myocardial infarction, has a 5.8 em. infrarenal aortic aneurysm. Imaging studies indicate an adequate proximal aortic neck to allow deployment of an endovascular prosthesis. Distally there is an appropriate landing zone in the aona to allow placement of a tube graft. The right iliac artelY

anatomy will accommodate passage of the main device. However, there is diffuse, severe anerial occlusive disease involving the entire left common and external iliac artery. Thus, it has been decided that the left common iliac will be occluded using endovascular technique, and a right-to-left femoral-femoral bypass graft will be placed to reperfuse the left leg. Description oj Procedw-e (34813) This procedure involves creation of an arching, curved subcutaneous tunnel from one femoral artery to the other. A specially designed curved, blunt-nosed tunneling device is used for this purpose. Care is taken not to "button-hole" the skin or enter the abdominal caVity. A synthetic conduit is chosen and pulled gently through the tunnel using care to avoid twisting or kinking. Intravenous heparin anticoagulant is administered and the femoral arteries are clamped with vascular hemostats. An appropriate aneriotomy is fashioned in the common femoral and an anastomosis is completed with fine polypropylene sutures. The graft is cut to appropriate length and a similar aneriotomy and anastomosis are performed on the opposite side. Vascular clamps are removed and hemostasis is obtained. The technical adequacy of the reconstruction is typically checked with handheld Doppler. The intra-service work of 348] 3 is complete at this point. Irrigation and closure of the wounds is included in the primary code 34812-50, and not reponed separately. Clinical F.xample (34820) A 67-year-old female with chronic obstructive pulmo-

nary disease and coronary artery disease, status post myocardial infarction, has a 5.8 em. infrarenal aonic aneurysm. Imaging studies indicate an adequate proximal aortic neck to allow deployment of an endovascular prosthesis. Distally there is an appropriate landing zone in the aorta to allow placement of a tube graft. Bilateral distal external iliac and common femoral arteries are too small in diameter to accommodate passage of the endovascular device. The decision has been made to perform surgical exposure of a more proximal segment of iliac artelY, where the diameter is larger, to provide a suitable entry site for placement of the device. Description oj Procedure (34820) A skin incision is made in the lower abdomen or retro-

peritoneum. The tissue is dissected deep into the pelVis until the iliac artery is located. Care is taken to avoid injury to the nerves, veins, and ureter that lie in close proximity. The arteries are dissected and isolated in vessel loops. Hemostasis is achieved by ligation or electrocautery. Intravenous heparin is administered before the arteries are clamped. A transverse arteriotomy is made in the anterior surface of the iliac artery for introduction of the guidewires and sheaths. The intra-service work of 34820 is interrupted until placement of the endovils~ular device has been completed. Once the device is successfully deployed, 34820

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resumes with closure of the arteriotomy using nne vascular suture, achievement of hemostasis, wound irrigation, and soft tissue reapproximation. Skin is closed with sunlres Or staples. Clinical Example (34825) A 67-year-old male with chronic obstructive pulmonaI)' disease and coronaI)' arteI)' disease, status post myocardial infarction, underwent endovascular repair of a 5.8 em diameter abdominal aortic aneuI)'sm (AAA). A distal anaSlOmotic endoleak is discovered by follow-up cr scan, and its exact nature is confirmed wiLh angiography (separately reportable) during post-operative follow-up. A distal endovascular extension will be placed to correct Lhe endoleak. (For radiological supervision and interpretation use 75953). Description of Procedure (34825) This procedure Lypically begins by passing an adequately large diameter sheath along the guidewire. The endovascular extension prosthesis is then advanced over the guidewire within the sheath. The device is carefully advanced through the iliac arteries and positioned such that the prOXimal and distal edges bridge the endoleak. Position is confirmed exactly by fluoroscopy, often with injections of comrast. Fine adjustments in position are made as needed. When in exactly the right position the extension cuff is deployed. Some devices require balloon dilatation to help assure proper seating and hemostatic seal (induded in service). If this is the case, a large diameter compliant balloon is advanced over (he wire, and under fluoroscopic guidance the balloon is positioned and inflated. An injection is performed to determine whether the endoleak has been sealed. Clinical Example (34826) A 67-year-old male with chronic obstructive pulmonaI)' disease and coronaI)' artery disease, status post myocardial infarction, underwent endovascular repair of a 5.8cm diameter abdominal aortic aneuI)'sm (AAA). An endoleak is discovered by follow-up cr scan one year after the procedure, and angiography (separately report· able) confirms leaks from one Iliac anastomosis as well as from the proXimal anastomosis. Endovascular extensions will be placed to correct endoleaks in both vessels. Description of Procedure (34826) This procedure lypically begins by passing an adequately large diameter sheath along the guidewire. The endovascular extension prosthesis is then advanced over lhe guidewire within the sheath. The device is carefully positioned such that the proximal and distal edges bridge the endoleak. Position is confirmed exactly by fluoroscopy, often with injections of contrast. Fine ad~ justments in position are made to assure exact positioning. The extension cuff is deployed. Some devices require balloon dilatation to help assure proper seating and hemostatic seal. If this is the case, a large diameter compliant balloon is advanced over the wire, and under

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fluoroscopic gUidance the balloon is pOSitioned and inflated. An injection is performed to determine whether the endoleak has been sealed. Clinical Example (34830) A 67-year-old male with chronic Obstructive pulmonaI)' disease and coronaI)' alteI)' disease, status post myocardial infarction has a 5.8 em. infra renal aortic aneuI)'sm. He undergoes attempted endovascular repair, but after lhe procedure has been underway for 5 hours it is de~ termined that the endoprosthesis cannot be completed successfully. The main body of the device is lodged in the distal infrarenal aorta. Description of Procedure (34830) This procedure includes dissection of the abdominal conrenrs and exposure of the aorta. Proximal and distal exposur~ of the aorta above and below (he aneurysm aIe accomplished. This exposure is typically more extensive than during routine elective AAA repair due to malposilioned or traumatized vessels. Intravenous heparin is administered for anticoagulation, and the blood flow in the aneUlysm is stopped by application of large vascular hemostats. The aneurysm is opened, bleeding lumbar arteries are suture ligated, and thrombus is removed. Any lodged pieces of endograft are removed. The proximal anaslOmosis of the prosthesis is sutured to normal, healthy, untraumatized aorta above the aneuI)'sm. The proximal clamp is removed and the anastomosis tested for hemostasis. Additional sunlres are placed as required. The distal anastomosis is carried out in a similar manner at the distal-most infrarenal aOrta. Following completion of all anastomoses, the vascular clamps are removed and blood flow is restored. Anticoagulation is reversed and hemostasis achieved. All wounds are irrigated and closed in layers. Clinical Example (34831) A 67-year-old male with chronic obstructive pulmonaI)' disease and coronary arteI)' disease, status post myocardial infarction, has a 5.8 em. infrarenal aortic aneuI)'sm. He undergoes attempted endovascular repair, but after the procedure has been underway for 5 hours it is determined that the endoprosthesis cannot be completed successfully. The main body of the device is lodged in the distal infra renal aorta. Description of Procedure (34831) This procedure includes dissection of the abdominal content.<; and exposure of the aorta. Proximal and distal exposure of the aorta above and below the aneurysm are accomplished. This exposure is Lypically more extensive than during routine elective AAA repair due to malposilioned or traumatized vessels. Intravenous heparin is administered for anticoagulation, and the blood flow in the aneUlysm is stopped by application of large vascular hemostats. The at1euI)'sm is opened, bleeding lumbar arteries are sLlture ligated, and thrombus is removed. Any lodged pieces of endograft are removed. The prox-

imal anastomosis of a bifurcated prosthesis is sutured to normal, healthy, untraumatized aolta above the aneurysm. The proximal clamp is removed and the anastomosis tested for hemostasis. Additional sutures are placed as required. The distal anastomoses are carried out in a similar manner to the iliac arteries. Following completion of all anastomoses, the vascular clamps are removed and blood flow is restored. Anticoagulation is reversed and hemostasis achieved. All wounds are irrigated and closed in layers. Clinical Example (34832) A 67-year-old male with chronic obstructive pulmonary disease and coronary altery disease, status post myocardial infarction, has a 5.8 cm. infrarenal aoltic aneurysm. He undergoes attempted endovascular repair, but after the procedure has been underway for 5 hours it is determined that the endoprosthesis cannot be completed successfully. The main body of the device is lodged in the distal infrarenal aorta. DeSc11ption of Procedure (34832) This procedure includes cUssection of the abdominal contents and exposure of the aorta. Proximal and distal exposure of the aorta above and below the aneurysm are accomplished. This exposure is typically more extensive than during routine elective AAA repair due to malpositioned or traumatized vessels. Intravenous heparin is administered for anticoagulation, and the blood flow in the aneurysm is stopped by application of large vascular hemostats. The aneurysm is opened, bleeding lumbar arteries are suture ligated, and thrombus is removed. Any lodged pieces of endograft are removed. The proximal anastomosis of a bifurcated prosthesis is sutured to normal, healthy, untraumatized aorta above the aneulysm. The proximal clamp is removed and the anastomosis tested for hemostasis. Additional sutures are placed as required. Since the distal common iliac arteries or external iliacs are involved with the aneurysm or have been traumatized during the endovascular procedure, the prosthetic limbs are tunneled through the pelvis with anastomoses performed at the femoral artery level. Following completion of all anastomoses, the vascular clamps are removed and blood flow is restored. Anticoagulation is reversed and hemostasis achieved. All wounds are irrigated and closed in layers. Transcatheter Procedures • 75952 Endovascular repair of infrarenal abdominal aortic aneurysm or dissection, radiological supervision and interpretation ~ (For implantation of endovascular grafts, see 34800-34808) • 75953 Placement of proximal or distal extension prosthesis for endovascular repair of infrarenal abdominal aortic aneurysm, radiological supervision and interpretation (For implantation of endovascular extension prostheses, see 34825, 34826)

Rationale Two new codes have been established to describe: 1) the radiologic guidance associated with placement of endovascular graft systems (5952); and 2) placement of a proximal or distal extension prosthesis (5953) associated with enovascular repair of infrarenal abdominal aortic aneurysm. Code 75952 includes angiography of the aOlta and its branches for diagnostic imaging prior to deployment of the endovascular device (including all routine components of modular devices), fluoroscopic guidance in the delivery of the endovascular components, and intra procedural arterial angiography (eg, confirm pOSition, detect endoleak, evaluate runoff). Code 75952 includes. angiography of the aorta and its branches for intraprocedural diagnostic imaging prior to deployment of the endovascular device (including aU routine components of modular devices), fluoroscopic guidance in the delivery of the endovascular components, and intra procedural arterial angiography (eg, confirm pOSition, detect endoleak, evaluate nll1off). Code 75953 includes the analogous services for placement of additional extension prostheses (not for routine components of modular devices). Placement of endovascular prqstheses for abdominal aortic aneurysm repair involves the use of both surgical and catheter-based skills associated with the various technologies. Because of the configuration of adjacent vessels, proper deployment of the endoluminal graft is extremely exacting and reqUires skills different from those required for open surgical repair. For instance, with endoluminal prosthesis, the physician operator(s) must 'get it right the first time' because, once deployed, the endoluminal grafts cannot be repositioned or retrieved. Advancing endoluminal grafts through tortuous vascular anatomy that is often associated with aneurysmal disease is technically challenging due to the large diameter and long lengths of the endoluminal devices. In cases with difficult anatomy, docking tl1e contralateral limbs in modular units can be one of the most time consuming, technically challenging portions of the procedure. Other interventional procedures performed at the time of endovascular abdominal aortic aneurysm repair should be additionally reported (eg, renal transJuminal angioplasty, arterial embolization, intravascular ultrasound, balloon angioplasty of native artery(s) outside me graft (eg, aortic or iliac) before deployment of endoprosthesis. Clinical Example (75952) A 67-year-old male wim chronic obstructive pulmonary disease and coronary artery disease, status post myocardial infarction, has a 5.8 em. aOltic aneurysm. Imaging studies (typically a combination of CT scan, MRI, IVUS, and/or angiography) indicate that the aneurysm is infrarenal and has an adequate neck to allow successful deployment of an endovascular prosthesis. Other ana-

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tomie considerations such as size, tortuosity, and calcification of the iliac arteries and presence of thrombus, plaque, and/or heavy calcification in the landing zones has also been evaluated.

Description of Procedure (5952) Angiographic "road-mapping" of aortic anatomy. • Fluoroscopic guidance of guidewires, catheters, endovascular prosthesis, and docking limbs (if utilized). • Fluoroscopic confirmation of appropriale placement of prosthesis and docking limbs, wilh or wilhout contrast. • Fluoroscopic guidance of inlra-prosthesis balloon dilatation, if necessary. • Supervision and interpretation of post-deployment aortogram for graft position, patency of appropriate branches (renals and hypogastrics), presence or absence of endoleaks, and patency of lumbar, hypogastric or inferior mesenteric arteries that may contribute to persistent endoleaks. • Interpretation of fiims and fluoroscopic imaging. • Balloon dilatation and/or intra-device steming to ensure proper seating, to fully open the graft, and/or to treat ~ndoleak (if present). Clinical Example (75953) A 67-year-old male with chronic obstruclive pulmonary disease and coronary artelY disease, status post myocardial infarction, underwem endovascular repair of a 5.8 cm. diameter abdominal aortic aneurysm. A distal anastomotic endoleak was discovered by CT scan one year later, and its exact nature is confirmed with angiography (separately reportable). A distal endovascular extension will be placed co correct the endoleak. Description of Procedure (75953) • Angiographic "road-mapping" of aortic anatomy • Fluoroscopic guidance of guidewires, catheters, endovascular extension(s) • Fluoroscopic guidance of deployment of endovascular extension(s), with or without contrast. • Fluoroscopic guidance of intra-extension balloon dilatation, and/or stent placement, if necessary. • Supervision and interpretalion of post-deployment aortogram for extension position, patency of appropriate branches (renals and hypogastrics), presence or absence of endoleaks, and patency of lumbar, hypogastric or inferior mesenteric arteries that may comribute to persistent encloleaks. Source: American Medical Association. CPT Changes 2001: An Insider's View.

365 p.m. Endoleaks: To Treat or Not To Treat? Richard A. Baum, MD Hospital of the University of Pennsylvania Philadelphia, Pennsylvania

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Introduction Allhough stent grafts are being used more frequently for the treatment of abdominal aortic aneurysms surprisingly little is known aboul the long-term effects of these devices. Reports of late graft failures ancl aneurysm ruptures have dampened the initjal enthusiasm for this procedure. It has become clear that the long term results of this type of repair differs Significantly from traditional aneurysm su rgery. Endoleaks, which do not occur after traditional aneurysm repair, remain the "AchiJles heel" of the new procedure. As many as one third of stent graft patients will develop endoleaks although the implications of these leaks are as yet unknown. Because endoleaks may develop at any point in lime, surveillance CT scans are needed at regular intervals CO confinn stent graft exclusion of the aneurysm from the systemic circulation. Classification of Endoleaks Endoleaks are claSSified into four categories. A leak at an attachment site (proximal, middle, or distal) is classified as type 1. In collateral endoleaks (type 2), blood travels from a branch vessel in the non stented portion of the aorta or iliac arteries. Blood flow takes a circuitous route emptying into the aneurysm sac via retrograde flow through a lumbar, inferior mesenteric (IMA) or other vessel originating from the aneurysm. This rype of leak is the most common, occurring in 200/0-30% of patients, and is unrelated to rhe type or configuration of stent graft used. Endoleaks thar are a result of a defect in or failure of the graft material are defined as type 3 while those due co stent graft wall porosity are called type 4. At our institution we have been unsuccessful in classifying endoleaks based on their C1' appearance alone. It is for this reason that we perform conventional angiography to confirm a leak's etiology before treatment. Angiography using high-pressure injection and rapid filming at each attachment site is performed. If this fails to reveal the leak, selective injection of aortic branch vessels (SMA, internal iJiacs, etc.) is performed to exclude type 2 (collateral) leaks. Because of the circuitous nature of these pathways it is important to film late into the venous phase. Do Endoleaks Need To Be Treated? Any discussion of .endoleak treatment must be kept in perspective. AB of this writing, the efficacy of any endoleak treatment has yet to be established. In fact, it is not even known whether or not stent graft patients with endoleaks have rupture rates different than patients without endoleaks. Although there is general agreement regarding the importance of treating attachment and~ graft related endoleaks, there is no such consensus regarding indications for remedia[ion of collateral leaks. While some of these leaks have been demonstrated to thrombose with the passage of time, distressing reports of continued AAA enlargement from untreated branch