Endovascular abdominal aortic aneurysm repair is less invasive, now we must prove its efficacy

Editor's Choice - Mid-term Migration and Device Failure Following Endovascular Aneurysm Sealing with the Nellix Stent Graft System - a Single Centre Experience

OBJECTIVE

Endovascular aneurysm sealing (EVAS) with the Nellix stent graft system is a novel concept in the management of abdominal aortic aneurysm (AAA) that aims to reduce the prevalence of all endoleaks following endovascular repair. There are few data describing the longer-term durability of this approach. The aim was to report the longer-term outcomes following EVAS in a single centre.

METHODS

This is a retrospective review of all patients that underwent Nellix at Cambridge University Hospitals Foundation Trust. Factors that are described as device failure include secondary sac rupture, graft explantation, further surgical procedures for Type 1 endoleak, or major migration of the stent grafts with pressurisation of the aortic sac.

RESULTS

A total of 161 patients have been treated with Nellix. The indications included primary AAA (n = 115), ruptured AAA (n = 4), salvage of other aortic grafts (n = 18), primary iliac aneurysm (n = 6), and chimney EVAS (ChEVAS) for pararenal AAA (n = 18). In total there have been 42 graft failures in patients treated with EVAS for primary AAA. The 4 year freedom from graft failure was 42% in patients treated for primary AAA. Failures mostly occurred more than 2 years post-Nellix implant. There were eight secondary sac ruptures (incidence 2.4 per 100 person years) and there have been 14 graft explants.

CONCLUSIONS

Failure of aneurysm sealing following treatment with Nellix has been more common than anticipated and can cause aortic rupture. Post-operative surveillance of Nellix stent grafts is crucial to identify features of failure.

A single-center experience in open and endovascular treatment of hemodynamically unstable and stable patients with ruptured abdominal aortic aneurysms

OBJECTIVE

To retrospectively compare a single center's immediate and mid-term outcomes of ruptured abdominal aortic aneurysm open and endovascular repair (EVAR) for two patient groups-hemodynamically stable and unstable patients-in the same time period.

METHODS

Patients presenting at our center with confirmed rupture of an abdominal aortic aneurysm between December 1999 and April 2006 were considered according to an intention-to-treat model with EVAR. Patients with symptomatic or acute (but not ruptured) AAAs were not included in this study. Thirty-three patients underwent EVAR, and 91 underwent open repair. Seventy-two patients (EVAR, 45%; open, 63%) were classified as hemodynamically unstable at arrival, and 52 were classified as stable (EVAR, 55%; open, 37%). Ninety-seven percent of EVAR procedures commenced under local anesthesia, and 100% of open repairs occurred with general anesthesia. Overall successful graft deployment, 30-day mortality, overall reintervention rate, and complications were the study primary end points.

RESULTS

Overall successful graft deployment for EVAR was 91%; for open repair, it was 96%. Overall 30-day mortality for EVAR was 30% (unstable, 53%; stable, 11%), and the rate was 46% for open repair (unstable, 61%; stable, 21%). The EVAR postoperative reintervention rate (within 30 days) was 15% (unstable, 20%; stable, 11%), and for open repair it was 10% (unstable, 9%; stable, 15%). We recorded a 27% severe complication rate for EVAR patients (unstable, 40%; stable, 17%), and for patients treated with open repair, it was 33% (unstable, 35%; stable, 29%). Our overall EVAR eligibility rate was 52%, and our overall EVAR treatment rate was 27%.

CONCLUSIONS

Our study's overall results for EVAR remain encouraging when compared with those of conventional repair, but large randomized trials are required to confirm the efficacy of the procedure.

Does N-Acetylcysteine Prevent Contrast-Induced Nephropathy During Endovascular AAA Repair? A Randomized Controlled Pilot Study

PURPOSE

To examine if N-acetylcysteine (NAC) reduces the incidence of contrast nephropathy during endovascular abdominal aortic aneurysm repair (EVAR) as evidenced by changes in markers of renal function.

METHODS

Twenty consecutive men (mean age 72 years, range 65-79) undergoing EVAR were randomized to receive standard intravenous fluid hydration or standard fluid hydration and NAC (600 mg BID orally, 4 doses). Venous blood and urine were collected prior to the procedure and for 5 postoperative days and analyzed blindly for serum creatinine, urinary retinol-binding protein (RBP), and albumin/creatinine ratio (ACR).

RESULTS

There were no significant differences in baseline demographics between the groups. No patient developed acute renal failure. In both groups, urinary RBP rose significantly from baseline (median 15 microg/mmol to peak 699 microg/mmol in controls versus 17 to 648 microg/mmol in the treatment group, p<0.003). There were similar significant rises in ACR (p<0.02). There was, however, no significant difference in the postoperative RBP or ACR between the groups at any time point.

CONCLUSION

EVAR causes significant acute renal injury in most patients. This was not attenuated by N-acetylcysteine. The causes of renal injury are probably multifactorial, the long-term clinical significance of which is unclear.

Existing Delays Following the Presentation of Ruptured Abdominal Aortic Aneurysm Allow Sufficient Time to Assess Patients for Endovascular Repair

OBJECTIVES

The greatest benefit of endovascular AAA repair (EVAR) may be in the management of rupture (RAAA). However, the detailed anatomical assessment required for EVAR has lead to concerns of surgical delay and death during cross-sectional imaging. In this study, we prospectively assessed patients with RAAA and correlated time of hospital arrival with time of surgery or death to ascertain whether these concerns are justified.

METHODS

All patients presenting with RAAA between October 2000 and December 2002 were included. The hospital arrival time, onset of surgery or time of death, were recorded, as were demographic and physiological parameters.

RESULTS

One hundred consecutive patients were studied, median age 75 years (range 54-94). Seventy-nine patients underwent attempted conventional surgical repair and 21 were palliated. The median delay from arrival to operation was 159 min (range 16-1450 min). Mortality in the surgical group was not affected by the length of delay (p = 1.0) or by CT scanning (p = 0.34). The median time from arrival to death in the non-surgical group was 435 min (15 min-6 days).

CONCLUSIONS

Most patients who present with ruptured AAA experience a significant delay prior to surgery. This study suggests it is safe to assess the majority of RAAA patients for EVAR.

Predicting Outcome in Ruptured Abdominal Aortic Aneurysm: A Prospective Study of 100 Consecutive Cases

OBJECTIVES

Case selection for surgery in patients presenting with ruptured abdominal aortic aneurysms (RAAA) is often difficult. A previous retrospective review identified five pre-operative risk factors associated with mortality [J Vasc Surg 23 (1996) 123]. In this study we aimed to identify whether these criteria could be usefully applied prospectively in patients presenting with RAAA.

METHODS

All patients presenting with RAAA from October 2000 to December 2002 were included. The criteria were recorded with the time they were available and the time surgery commenced. The decision to operate was made on clinical grounds and no patient was refused surgery on the basis of these criteria.

RESULTS

One hundred consecutive patients were studied, median age 75 (range 54-94). The operative mortality was 32.9% (26/79 patients). Surgical mortality increased with the number of positive criteria and was 8% (2/24), 24% (7/29), 55% (11/20) and 100% (6/6) for scores, 0, 1, 2 and > or =3, respectively. Age and conscious level were available in every patient. However, an ECG, haemoglobin and creatinine results were only available in 94, 81, and 69%, respectively.

CONCLUSIONS

The scoring system accurately predicted operative mortality. The score was available in the majority of cases and may help the surgeon give informed consent to patients and relatives prior to surgical intervention.