ANNALS OF SURGERY
`Vol. 235, No. 6, 833–841
`© 2002 Lippincott Williams & Wilkins, Inc.
`
`Endovascular Repair of Abdominal Aortic Aneurysms
`Risk Stratified Outcomes
`
`Elliot L. Chaikof, MD, PhD, Peter H. Lin, MD, William T. Brinkman, MD, Thomas F. Dodson, MD, Victor J. Weiss, MD,
`Alan B. Lumsden, MD, Thomas T. Terramani, MD, Sasan Najibi, MD, Ruth L. Bush, MD, Atef A. Salam, MD,
`and Robert B. Smith, III, MD
`From the Division of Vascular Surgery, Emory University School of Medicine, Atlanta, Georgia
`
`Objective
`The impact of co-morbid conditions on early and late clinical
`outcomes after endovascular treatment of abdominal aortic
`aneurysm (AAA) was assessed in concurrent cohorts of pa-
`tients stratified with respect to risk for intervention.
`
`Summary Background Data
`As a minimally invasive strategy for the treatment of AAA, en-
`dovascular repair has been embraced with enthusiasm for all
`prospective patients who are suitable anatomical candidates
`because of the promise of achieving a durable result with a
`reduced risk of perioperative morbidity and mortality.
`
`Methods
`From April 1994 to March 2001, endovascular AAA repair
`was performed in 236 patients using commercially available
`systems. A subset of patients considered at increased risk for
`intervention (n ⫽ 123) were categorized, as such, based on a
`preexisting history of ischemic coronary artery disease, with
`documentation of myocardial infarction (60%) or congestive
`heart failure (35%), or due to the presence of chronic obstruc-
`tive disease (21%), liver disease, or malignancy.
`
`Results
`Perioperative mortality (30-day) was 6.5% in the increased-
`risk patients as compared to 1.8% among those classified as
`low risk (P ⫽ NS). There was no difference between groups in
`age (74 ⫾ 9 years vs. 72 ⫾ 6 years; mean ⫾ SD), surgical
`time (235 ⫾ 95 minutes vs. 219 ⫾ 84 minutes), blood loss
`
`(457 ⫾ 432 mL vs. 351 ⫾ 273 mL), postoperative hospital
`stay (4.8 ⫾ 3.4 days vs. 4.0 ⫾ 3.9 days), or days in the ICU
`(1.3 ⫾ 1.8 days vs. 0.5 ⫾ 1.6 days). Patients at increased risk
`of intervention had larger aneurysms than low-risk patients
`(59 ⫾ 13 mm vs. 51 ⫾ 14 mm; P ⬍ .05). Stent grafts were
`successfully implanted in 116 (95%) increased-risk versus
`107 (95%) low-risk patients (P ⫽ NS). Conversion rates to
`open operative repair were similar in increased-risk and low-
`risk groups at 3% and 5%, respectively. The initial endoleak
`rate was 22% versus 20%, based on the first CT performed
`(either at discharge or 1 month; P ⫽ NS). To date, increased-
`risk patients have been followed for 17.4 ⫾ 15 months and
`low-risk patients for 16.3 ⫾ 14 months. Kaplan-Meier analysis
`for cumulative patient survival demonstrated a reduced prob-
`ability of survival among those patients initially classified as at
`increased risk for intervention (P ⬍ .05, Mantel-Cox test).
`Both cohorts had similar two-year primary and secondary
`clinical success rates of approximately 75% and 80%,
`respectively.
`
`Conclusions
`Early and late clinical outcomes are comparable after endovas-
`cular repair of AAA, regardless of risk-stratification. Notably, 2
`years after endovascular repair, at least one in five patients was
`classified as a clinical failure. Given the need for close life-long
`surveillance and the continued uncertainty associated with clini-
`cal outcome, caution is dictated in advocating endovascular
`treatment for the patient who is otherwise considered an ideal
`candidate for standard open surgical repair.
`
`With the advent of an endovascular treatment option for
`the abdominal aortic aneurysm (AAA), defining an appro-
`
`Dr. Chaikof has been paid a consulting fee and received clinical research
`funding from Guidant. Dr. Lumsden has been paid a consulting fee and
`received clinical research funding from Meditronic and W. L. Gore.
`Correspondence: Elliot L. Chaikof, MD, PhD, 1639 Pierce Drive, Room
`5105, Emory University, Atlanta, GA 30322.
`E-mail: echaiko@emory.edu
`
`priate strategy for the referral of patients to either open or
`endovascular repair remains a complex clinical endeavor.
`For example, patients who were otherwise appropriate sur-
`gical candidates for standard open repair have populated
`most, if not all, industry-sponsored clinical trials conducted
`
`Presented at the 113th Annual Session of the Southern Surgical Associa-
`tion, December 3–5, 2001, Hot Springs, Virginia.
`Accepted for publication December 2001.
`
`833
`
`TMT 2112
`Medtronic v. TMT
`IPR2021-01532
`
`

`

`834
`
`Chaikof and Others
`
`Ann. Surg. ● June 2002
`
`in the United States.1–3 Among these patients, a significant
`reduction in hospital stay has been demonstrated, with early
`return to preoperative levels of activity. Enthusiasm for
`endovascular treatment for the patient at low risk has also
`been coupled with the proposition that endovascular therapy
`provides an ideal approach for patients in whom standard
`operative repair carries an increased risk of perioperative
`morbidity and mortality.4 Indeed, endovascular treatment
`has increased the proportion of patients now referred for
`AAA repair by providing therapy for patients who have
`been deemed inoperable because of the presence of signif-
`icant comorbid conditions. Nonetheless, the widespread ad-
`vocacy of endovascular grafting as a preferred option to
`open surgery for potentially all anatomically suitable pa-
`tients continues during a period when most studies have
`reported outcomes that are largely confined to early inter-
`vals after intervention.
`We recently reported the clinical experience with endo-
`vascular AAA repair at our institution.5 This updated report
`reviews our mid-term experience with endovascular AAA
`repair over a 7-year period by examining early and late
`clinical outcome in concurrent cohorts of patients stratified
`either as patients at low risk, who would otherwise be
`considered ideal open surgical candidates, or as those who
`are at increased risk for intervention. In these two groups of
`patients, we assessed perioperative morbidity and mortality,
`technical success, and late clinical success rates and patient
`survival.
`
`METHODS
`
`Patient Selection
`
`Data for 236 consecutive patients undergoing elective
`endovascular AAA repair at Emory University Hospital
`(Atlanta, GA) were retrospectively collected from April
`1994 through March 2001. An endovascular program was
`initially instituted at Emory University as part of an inves-
`tigator-sponsored, investigational trial (Endovascular Tech-
`nologies, Inc, Menlo Park, Calif/Guidant, Inc, Indianapolis,
`ID). This program expanded in 1999 to include a second
`investigational device (Excluder, WL Gore and Associates,
`Inc, Flagstaff, AZ). We have also used the AneuRx
`(Medtronic, Inc, Sunnyvale, CA) endograft system after its
`approval by the Food and Drug Administration for com-
`mercial use in September 1999. During the study period,
`implanted endografts included the EVT/Guidant endograft
`(n ⫽ 150), the AneuRx stent graft system (n ⫽ 58), and the
`Excluder endograft (n ⫽ 28). The EVT/Guidant endografts
`included tube (n ⫽ 26), bifurcated (n ⫽ 109), and aortoiliac
`endografts combined with a femorofemoral bypass graft
`(n ⫽ 15). The Gore endografts were all phase II devices.
`Patients were considered at increased risk for intervention
`if there was 1) documentation of previous myocardial in-
`farction (MI) or congestive heart failure; 2) significant re-
`spiratory disease as demonstrated by a forced expiratory
`
`volume in 1 second of ⬍ 1 liter/min or a requirement for
`home oxygen therapy; 3) chronic liver disease with docu-
`mented cirrhosis or portal hypertension, or; 4) the presence
`of concurrent or recent malignancy. Of note, all patients
`underwent preoperative cardiac risk assessment
`that
`in-
`cluded dobutamine echocardiography or persantine thallium
`scanning.
`
`Endograft Implantation
`
`All endovascular AAA repairs were performed in a stan-
`dard operating room environment with complete angio-
`graphic capability by a team of vascular surgeons and
`interventional radiologists. The techniques of transfemoral
`endovascular AAA prosthesis implantation have been de-
`scribed previously.1– 4,6 Fluoroscopic guidance (OEC 9600,
`OEC Medical Systems, Inc, Thousand Oaks, CA) was used
`for placement of the endoprosthesis, and most of the pro-
`cedures were performed with the patients under general
`anesthesia. All patients underwent systemic anticoagulation
`with 100 U/kg heparin. Postimplantation aortography was
`performed to assess graft positioning, vessel patency,
`periprosthetic leakage, and graft limb stenosis. Type I en-
`doleaks, (leakage around the proximal or distal attachment
`site) were treated during the operation with additional en-
`dovascular measures. Type II endoleaks (those through ret-
`rograde lumbar or inferior mesenteric arteries) were ob-
`served and monitored with serial CT scans. At the discretion
`of the attending physician, this type of endoleak was treated
`with coil embolization of the patent collateral pathway.
`
`Clinical Follow-up
`
`Contrast-enhanced CT was performed either in the im-
`mediate postoperative period or within 1 month of endograft
`placement. Additional imaging studies including CT, du-
`plex ultrasound scanning, and plain abdominal x-ray eval-
`uation were performed at 6 months, 12 months, and then
`annually thereafter. If an endoleak was visualized, more
`frequent surveillance imaging was performed as clinically
`indicated.
`
`Definitions
`
`All perioperative complications are described. However,
`major morbidity was defined as any complication that re-
`sulted in an increase in hospital stay, a secondary surgery, or
`a significant disability. The definitions of technical success,
`clinical success, and continuing success as described by the
`Society for Vascular Surgery/International Society for Car-
`diovascular Surgery (SVS/ISCVS) Ad Hoc Committee on
`Reporting Standards for Endovascular AAA Repair were
`used.7 In brief, 30-day technical success was defined on an
`intent-to-treat basis as successful endograft deployment
`without death, need for standard aortic reconstruction for 30
`days, or evidence of persistent (⬎48 hours) endoleak. Clin-
`
`

`

`Vol. 235 ● No. 6
`
`Endovascular Repair of Abdominal Aortic Aneurysms
`
`835
`
`Table 1. CHARACTERISTICS DEFINING
`PATIENTS AT INCREASED RISK FOR
`INTERVENTION (n ⴝ 123)*
`
`Characteristic
`
`Congestive heart failure
`Myocardial infarction
`Respiratory disease†
`Chronic liver disease-cirrhosis/portal hypertension††
`Malignancy§
`
`No (%)
`
`43 (35)
`74 (60)
`26 (21)
`7 (6)
`9 (7)
`
`* Patients may have had more than one factor increasing the risk of intervention.
`† Chronic obstructive pulmonary disease documented by pulmonary function
`testing with a forced expiratory volume in 1 second ⱕ1 L/min or the need for
`home oxygen therapy.
`†† Child’s class B.
`§ Primary lung cancer (n ⫽ 5), metastatic colon cancer (n ⫽ 2; Duke’s stage D),
`laryngeal cancer (n ⫽ 1), transitional cell carcinoma of the bladder (n ⫽ 1).
`
`ical success was inclusive of those patients who at 6 months
`after implantation had spontaneously sealed a persistent
`endoleak and had demonstrated no evidence of aneurysm
`enlargement. Secondary clinical success was used if addi-
`tional endovascular techniques were required to seal an
`endoleak. Continuing success was defined as the mainte-
`nance of both clinical and technical success without evi-
`dence of graft thrombosis, infection, endoleak, or aneurysm
`expansion of greater than 0.5 cm. Any late graft complica-
`tion that was successfully treated by an endovascular tech-
`nique was classified as a secondary continuing success.
`Other outcomes analyzed included successful graft deploy-
`ment irrespective of the presence or absence of endoleak,
`surgical time, operative blood loss, duration of stay in an
`intensive care unit, length of hospital stay, and patient
`survival.
`
`Statistical Analysis
`Descriptive data are expressed as mean ⫾ SD. Continu-
`ous variables were compared with the use of the Student
`
`Table 3. TYPES OF ENDOGRAFTS
`IMPLANTED
`
`Graft Type
`
`Increased-risk Group
`(n ⴝ 123) (%)
`
`Low-risk Group
`(n ⴝ 113) (%)
`
`Bifurcated (Guidant)
`Tube (Guidant)
`Aortoiliac* (Guidant)
`AneuRx (Medtronic)
`EXCLUDER (Gore)
`Conversions†
`Aborted procedures†
`
`54 (44)
`9 (7)
`13 (11)
`37 (30)
`17 (14)
`3 (2)
`4 (3)
`
`52 (46)
`19 (17)
`3 (2)
`21 (19)
`11 (10)
`6 (5)
`0 (0)
`
`* Aortoiliac endograft performed in conjunction with contralateral common iliac
`artery occlusion and femorofemoral cross-over graft.
`† No significant difference when analyzed by Fischer’s exact test.
`
`t-test. Nominal variables were analyzed by contingency
`tables. The Kaplan-Meier method with Mantel-Cox (log-
`rank) posthoc analysis was used to determine success and
`survival rates. P ⬍ .05 was considered statistically signifi-
`cant. An SAS statistical package was used for analysis
`(Version 5.0, Abacus Concepts, Berkeley, CA).
`
`RESULTS
`Between April 1994 and March 2001, elective endovas-
`cular repair of infrarenal AAA was carried out on 236
`patients, with 123 (52%) procedures conducted in patients
`classified at increased risk and 113 (48%) procedures per-
`formed in patients considered low risk for major morbidity
`or mortality. The incidence of comorbid conditions among
`patients deemed at increased risk for intervention is pre-
`sented in Table 1. Patient and procedural characteristics for
`these two groups are summarized in Table 2, and the types
`of endografts implanted are described in Table 3.
`Notably, cardiac disease was a major indication for the
`categorization of patients at increased risk for intervention.
`To obtain a more precise determination of the severity of
`
`Table 2. COMPARISON OF PATIENT SUBGROUPS UNDERGOING ENDOVASCULAR
`AAA REPAIR
`
`Characteristic
`
`Age (y)
`AAA size (mm)
`Preprocedure serum creatinine level (mg/dL)
`Operative time (min)*
`Blood loss (mL)*
`Postoperative stay (days)*
`ICU stay (days)*
`
`Mean ⫾ SD.
`NS, No statistical significance; ICU, intensive care unit.
`* Includes only patients having successful endograft deployment.
`
`Increased-risk group
`(n ⴝ 123)
`
`Low-risk group
`(n ⴝ 113)
`
`73.9 ⫾ 9.2
`59.2 ⫾ 13.3
`1.2 ⫾ 0.5
`235 ⫾ 95
`457 ⫾ 432
`4.8 ⫾ 3.4
`1.3 ⫾ 1.8
`
`72.1 ⫾ 6.3
`51.2 ⫾ 13.9
`1.1 ⫾ 0.6
`219 ⫾ 84
`351 ⫾ 273
`4.0 ⫾ 3.9
`0.5 ⫾ 1.6
`
`P Value
`
`NS
`.007
`NS
`NS
`NS
`NS
`NS
`
`

`

`836
`
`Chaikof and Others
`
`Ann. Surg. ● June 2002
`
`cardiac disease in our population, additional risk stratifica-
`tion of patients was performed with the SVS/ISCVS Car-
`diac Grading System.8 In brief, cardiac status is graded with
`a 0 to 3flat scale where grade 0 indicates a patient with no
`symptoms and a normal electrocardiogram (ECG); grade 1
`is used for a patient with no symptoms and a history of a
`remote MI (⬎ 6 months), occult MI by ECG, or fixed defect
`on dipyridamole thallium or similar scan; grade 2 is used for
`the patient with stable angina, the presence of a significant
`reversible perfusion defect on dipyridamole thallium scan,
`ejection fraction of 25% to 45%, controlled ectopy/arrhyth-
`mia, or compensated congestive heart failure; and grade 3 is
`used for patients with unstable angina, ejection fraction of
`less than 25%, symptomatic or poorly controlled ectopy/
`arrhythmia, poorly compensated or recurrent congestive
`heart failure, or MI within 6 months. Patients in the study
`classified as low risk (n ⫽ 113) had an SVS/ISCVS cardiac
`score of 0, whereas patients categorized at increased risk
`solely by a history of cardiac disease had a score of 1.82 ⫾
`0.53 (n ⫽ 71). Of note, most patients with cardiac disease
`had a score of 2 (58%; 41 of 71) or 3 (8%; 6 of 71).
`
`Technical and Clinical Success
`
`Endovascular stent graft deployment was successful in
`116 (95%) of 123 of patients at increased risk and in 107
`(95%) of 113 patients at low risk, with conversion rates of
`2.4% and 5.3%, respectively. No intraoperative deaths oc-
`curred. Intraoperative conversions to open repair and/or
`aborted procedures all occurred during attempted implanta-
`tion of EVT/Guidant endografts, except one case of at-
`tempted AneuRx endograft placement. These technical fail-
`ures were not clustered during any given time period. In the
`increased-risk group, there were three immediate conver-
`sions to open repair and four aborted procedures. The sole
`case of AneuRx endograft conversion occurred when a
`contralateral catheter was caught in the nitinol strut and was
`unable to be removed. In the second case of immediate
`conversion, the distal attachment hooks of an EVT/Guidant
`tube graft became caught on the aortic bifurcation and were
`unable to be released. In the third case, a device twist was
`not resolvable with endoluminal techniques. Two aborted
`procedures occurred in patients with tortuous, heavily cal-
`cified iliac arteries. One patient subsequently died of pro-
`gressive congestive heart failure several weeks after hospi-
`tal discharge, while the other patient declined open repair.
`The third and fourth aborted procedures were also related to
`an inability to access the aneurysm. The third patient de-
`clined open repair and subsequently had a fatal aneurysm
`rupture, and the fourth patient died 6 months later. The cause
`of death in this patient was not determined. A late conversion
`also occurred in this group at 30 months. A patient who
`underwent implantation with the original EGS (EVT, Inc.)
`system had attachment system failure in the form of a hook
`fracture. This was recognized because of the presence of a
`persistent endoleak and aneurysm enlargement.
`
`The results for the low-risk group were similar, with six
`conversions. Two were related to iliac artery injury and two
`to the inability to access the aneurysm because of narrowed
`and calcified iliac arteries. Two cases of EVT/Guidant de-
`vice malfunction occurred during deployment. In all six
`cases that required conversion, successful open repair was
`performed without postoperative complications. Two late
`conversions occurred in the low-risk group, one a conse-
`quence of a hook fracture identified at 26 months and the
`other of a graft infection at 2 months.
`The 30-day technical success rates as defined by the
`SVS/ISCVS reporting standards were 73% for the in-
`creased-risk group and 78% for the low-risk group (P ⫽
`NS). At 1 month after implantation, 25 (20.3%) patients at
`increased risk and 21 (19.6%) at low risk had endoleaks
`detected by CT imaging. These results remained essentially
`unchanged at 6 months, with clinical success rates at 6
`months of 83% for the patients at increased risk and 80% for
`the low-risk cohort. Thirteen patients at increased risk and
`five at low risk had spontaneous sealing of their endoleaks.
`All remaining endoleaks were observed during this period,
`and no further intervention was taken in this regard. A
`statistically significant relationship between Type I and II
`endoleaks and graft type was not detected. Continuing pri-
`mary and secondary success as defined by the SVS/ISCVS
`reporting standards are represented in Figure 1 and were
`73.5% ⫾ 10.2% and 76.5% ⫾ 9.3% for increased-risk and
`low-risk groups, respectively, at 24 months. If the definition
`of clinical success is revised to exclude the presence of a
`Type II endoleak, Kaplan-Meier analysis revealed clini-
`cal success rates at 24 months of 76.2% ⫾ 19.60% and
`82.3% ⫾ 11.50% for increased-risk and low-risk groups,
`respectively.
`Adjunctive endovascular techniques were used in both
`groups to facilitate graft implantation and aneurysm exclu-
`sion. In 11 patients with increased risk, one or both limbs of
`a bifurcated graft had intraluminal stents placed for fabric
`folds observed with either intravascular ultrasound scanning
`or angiography at the time of endograft deployment. Intralu-
`minal stents were also placed in 19 patients at low risk.
`Internal iliac arteries were unilaterally embolized in 13
`patients (seven at high risk, six at low risk) for the exclusion
`of ectatic or aneurysmal common iliac arteries. Iliac artery
`dissection was noted in one patient in each study group at
`the time of graft implantation and was treated successfully
`in both cases with stent coverage.
`
`Complications
`
`The perioperative complication rate was 17.5% and
`15.0% in the increased- and low-risk groups, respectively
`(Table 4). All wound infections were superficial and suc-
`cessfully treated on an outpatient basis with local wound
`care and antibiotic therapy. Two patients developed acute
`renal failure necessitated hemodialysis. Overall, major mor-
`bidity necessitating an increase in hospital stay or signifi-
`
`

`

`Vol. 235 ● No. 6
`
`Endovascular Repair of Abdominal Aortic Aneurysms
`
`837
`
`Figure 2. Cumulative survival rates for low-risk (‘) and increased-risk
`(F) groups presented by Kaplan-Meier method. A statistically significant
`difference in survival
`in favor of the low-risk group was noted by the
`log-rank test (P ⬍ .035).
`
`cant disability occurred in 4% (5 of 123) of patients at
`increased risk and 6% (7 of 113) of patients at low risk.
`
`Follow-up
`Follow-up data were complete for all patients, with a
`mean follow-up interval of 17.4 ⫾ 15 months for patients at
`high risk and 16.3 ⫾ 14 months for the low-risk group. No
`patient was lost to follow-up. The perioperative (30-day)
`mortality rates were 6.5% and 1.8% for the increased-risk
`and low-risk groups, respectively (P ⫽ .2013, Fisher exact
`test). Eight perioperative deaths occurred in the group at
`increased risk for intervention. One death occurred in a
`patient who required conversion from endovascular repair
`to open repair and one in a patient who had an aborted
`procedure and severe coronary artery disease. The third
`death occurred in a patient who had a successful endovas-
`cular repair without evidence of postoperative endoleak. A
`malignant arrhythmia was the presumed cause of death.
`Two deaths occurred due to postoperative myocardial isch-
`emia. One patient with severe chronic obstructive pulmo-
`nary disease and emphysema developed pneumonia postop-
`eratively. He developed adult respiratory distress syndrome
`that eventually contributed to his death. The seventh patient
`developed acute renal failure and pneumonia postopera-
`tively and died two weeks following the endovascular an-
`eurysm repair. The eighth patient died of severe heart failure
`after hospital discharge. Endograft deployment had been
`successful in this patient, and no endoleak had been detected
`by CT scanning at the time of discharge. Fifteen other
`patients died during the follow-up period.
`In the low-risk group, two perioperative and nine late
`deaths occurred. One death was due to intraoperative hem-
`orrhage and another death occurred due to presumed post-
`
`Figure 1. Primary (A) and secondary (B) continuing success rates for
`low-risk (‘) and increased-risk (F) groups presented by Kaplan-Meier
`method. Statistically significant differences in success rates were not
`observed.
`
`Table 4. PERIOPERATIVE (30-DAY)
`COMPLICATIONS
`
`Complication
`
`Wound infection
`Re-exploration for hemostasis
`Myocardial infarction
`Renal failure (dialysis requirement)
`Deep venous thrombosis/pulmonary
`embolism
`Graft twist*
`Common femoral artery injury
`Pneumonia
`
`Increased-
`risk Group
`(n ⴝ 120)
`
`Low-risk
`Group
`(n ⴝ 107)
`
`11
`2
`2
`1
`0
`
`1
`3
`1
`
`8
`3
`1
`1
`2
`
`0
`1
`0
`
`* Twisting of one limb of a nonsupported bifurcated graft required treatment with
`a femorofemoral crossover graft at the time of stent graft implantation.
`
`

`

`838
`
`Chaikof and Others
`
`Ann. Surg. ● June 2002
`
`operative pulmonary embolism. Kaplan-Meier cumulative
`survival curves are shown in Figure 2. The two-year mor-
`tality rates were 26.5% ⫾ 8.1% and 14.2% ⫾ 7.5% for the
`increased- and low-risk groups, respectively. A significant
`difference between the two patient cohorts was noted by the
`Mantel-Cox (log-rank) test (P ⫽ .035). None of the reported
`late deaths in our series were related to the initial endovas-
`cular procedure, device failure, or late aneurysm rupture.
`
`DISCUSSION
`
`The introduction of endovascular grafting was a mile-
`stone in the treatment of patients with AAA in that it
`provided a treatment option for those patients with large
`aneurysms who had been deemed inoperable because of the
`presence of significant medical comorbidities.4 In the ex-
`tension of this technology to all patients with aneurysmal
`disease, clinical investigations have confirmed that com-
`pared with open surgery, an early benefit in quality of life
`can be achieved, as it relates to reducing hospital stay and
`recovery period.1,2 Nonetheless, even minimally invasive
`interventions may be associated with an adverse early out-
`come, and the presumption that an endovascular approach
`reduces perioperative mortality in patients at low risk com-
`pared with the results of standard surgery remains unproven.
`Moreover, an early benefit in quality of life may be offset by
`a lower level of late clinical success that carries with it a
`requirement for more intensive long-term surveillance, in-
`creased rates of reintervention, and higher costs and psy-
`chological stress. Thus, in advocating endovascular treat-
`ment for patients who are at low risk for operative repair, a
`critical analysis of late outcomes is required.
`In our retrospective analysis, patients classified at low
`risk for intervention with accepted clinical and laboratory
`criteria exhibited a 30-day mortality rate of 1.8% after
`endovascular intervention. This result is of particular inter-
`est in the context of a recent review of open aortic surgery
`performed on 856 patients at our institution between 1986
`and 1996.9 The in-hospital mortality rate was 1.3%, with a
`major complication rate of 15.9%. Thus, although the data
`generated by these two distinct reviews at the Emory Uni-
`versity Hospital are not strictly comparable, our experience
`suggests that in the patient at low risk, endovascular treat-
`ment of the infrarenal AAA is not associated with a reduc-
`tion in perioperative mortality compared with standard sur-
`gical repair.
`Many reports, nevertheless, confirm that endovascular
`strategies do offer unique advantages among those patients
`whose comorbid conditions increase the risk of major com-
`plications including death. For example, May et al.10 com-
`pared outcomes of patients treated concurrently with either
`open or endovascular repair. Although more than 40% of
`patients treated with endografts had been declined open
`repair because of comorbid illness, no significant difference
`in perioperative mortality rates or long-term survival was
`observed. In addition, Chuter et al.11 observed a 30-day
`
`mortality rate of 1.7% in their review of patients treated by
`endovascular approaches that had otherwise been refused
`conventional AAA repair. In their patient population, cor-
`onary artery disease was present in 81%, congestive heart
`failure in 34%, and respiratory disease in 49%. These re-
`ports compare favorably with published studies of conven-
`tional open aneurysmectomy in patients at high risk that
`have been associated with mortality rates of up to 40%.12–14
`Our review does reemphasize, however, that conversion
`to an open repair and the aborting of an endograft procedure
`may not be well tolerated among those patients with signif-
`icant comorbidities. This is consistent with results reported
`by May et al.,10,15 who have noted mortality rates of 18% to
`43% when primary conversion was required for patients
`considered at prohibitive risk for standard surgery. It is our
`view that both the prolonged anesthesia time and the blood
`loss incurred during a preliminary attempt at endovascular
`repair before conversion are important contributing factors
`to these poor results. Therefore, a cautious approach should
`be adopted in recommending endovascular repair for the
`patient at high risk in the presence of anatomical constraints,
`which might reduce the potential for successful endograft
`deployment.
`With SVS/ISCVS-recommended reporting standards, 30-
`day primary technical success, 6-month clinical success,
`and 24-month primary and secondary continuing clinical
`success rates were all approximately 75% in both study
`subgroups. Our 30-day primary technical success rate is
`similar to the 77% rate reported by Zarins et al.2 for
`190 patients treated as part of the multicenter Medtronic
`AneuRx stent graft trial. Likewise, our 24-month success
`rate is comparable to that recently reported by May et al.16
`for second-generation endovascular prostheses used in 148
`patients. Thus, although these results are encouraging and
`will undoubtedly improve in coming years, the success of
`endovascular repair remains uncertain in a significant pro-
`portion of patients. Two years after endograft implantation,
`25% of all patients were classified as failures with the
`SVS/ISCVS reporting standards definition.7 Therefore, in
`advocating an aggressive approach for endovascular inter-
`vention in the patient who is an otherwise ideal surgical
`candidate, it is also important to recognize that significant
`limitations to endovascular repair remain. Moreover, the
`impact of this failure rate on increasing costs and reducing
`patient quality of life is probably significant but admittedly
`was not defined in this report.
`It is notable that all reported late deaths in our series were
`unrelated to the initial endovascular procedure, device fail-
`ure, or late aneurysm rupture. Although late survival was
`significantly compromised in those patients who were
`deemed at increased risk for intervention, 75% were alive at
`2 years. These results are not unexpected, and others have
`reported similar late mortality rates for patients initially
`considered poor surgical candidates.11 Nonetheless, all of
`this suggests that the benefit of endovascular repair may be
`limited for patients who have a compromised life expect-
`
`

`

`Vol. 235 ● No. 6
`
`Endovascular Repair of Abdominal Aortic Aneurysms
`
`839
`
`ancy. In this regard, patients with a concomitant history of
`recent or concurrent malignant disease are a subgroup of
`particular interest. Of the nine patients in this group, two
`died of progressive cancer 12 months after endovascular
`AAA repair. However, the six remaining patients were alive
`at the time of last follow-up (12.4 ⫾ 8.2 months). Thus,
`given the imprecision in predicting the risk of AAA rupture
`and long-term survival either in response to cancer therapy
`or other major medical illness, decisions to proceed with
`endovascular repair must be carefully individualized. In this
`regard, we presently advocate endovascular intervention for
`the patient with significant medical comorbidity only when
`aneurysm size is equal to or exceeds 6 cm in diameter and
`patient life expectancy is estimated to exceed 2 years. We
`believe this to be a prudent recommendation given respec-
`tive annual rates of rupture of approximately 6.6% and 19%
`for untreated patients with 5.7-cm and 7.0-cm diameter
`aortic aneurysms17 and our combined major morbidity and
`30-day mortality rate of 12% for the patient at increased risk
`for intervention.
`In summary, our analysis suggests that endovascular an-
`eurysm repair currently remains most appropriate for those
`patients with large aneurysms who are otherwise prohibitive
`operative candidates. It
`is significant
`that endovascular
`grafting provides these patients with a treatment option
`when one was not previously available. Advocating endo-
`vascular treatment for the patient who is at low risk for
`standard operative intervention remains problematic. Al-
`though clinical success can be achieved in most patients,
`inadequate results continue to be observed in a significant
`portion. In deciding on a course of treatment, an informed
`decision on the part of the patient requires a consideration of
`these data and an appreciation that endovascular aortic
`aneurysm repair remains in a relatively early stage of
`development.
`
`References
`
`1. Moore WS, Rutherford RB. Transfemoral endovascular repair of ab-
`dominal aortic aneurysm: results of the North American EVT phase 1
`trial. EVT Investigators. J Vasc Surg 1996; 23:543–53.
`2. Zarins CK, White RA, Schwarten D, et al. AneuRx stent graft versus
`open surgical repair of abdominal aortic aneurysms: multicenter pro-
`spective clinical trial. J Vasc Surg 1999; 29:292–305; discussion
`306 – 8.
`3. White RA, Donayre CE, Walot I, et al. Modular bifurcation endopros-
`thesis for treatment of abdominal aortic aneurysms. Ann Surg 1997;
`226:381–9; discussion 389 –91.
`4. Parodi JC, Palmaz JC, Barone HD. Transfemoral intraluminal graft
`implantation for abdominal aortic aneurysms. Ann Vasc Surg 1991;
`5:491–9.
`5. Bush RL, Lumsden AB, Dodson TF, et al. Mid-term results after
`endovascular repair of the abdominal aortic aneurysm. J Vasc Surg
`2001; 33:S70 – 6.
`6. Harris EJ. Modular systems in the treatment of abdominal aortic
`aneurysms: lessons learned in the development of designer endografts.
`Semin Vasc Surg 1999; 12:170 –5.
`7. Ahn SS, Rutherford RB, Johnston KW, et al. Reporting standards for
`infrarenal endovascular abdominal aortic aneurysm repair. Ad Hoc
`
`Committee for Standardized Reporting Practices in Vascular Surgery
`of The Society for Vascular Surgery/Inte