Prevention of paraplegia in transluminally placed endoluminal prosthetic grafts for descending thoracic aortic aneurysms

Strategies to Manage Paraplegia Risk After Endovascular Stent Repair of Descending Thoracic Aortic Aneurysms

BACKGROUND

Paraplegia is a recognized complication after endovascular stent repair of descending thoracic aortic aneurysms. A management algorithm employing neurologic assessment, somatosensory evoked potential monitoring, arterial pressure augmentation, and cerebrospinal fluid drainage evolved to decrease the risk of postoperative paraplegia.

METHODS

Patients in thoracic aortic aneurysm stent trials from 1999 to 2004 were analyzed for paraplegic complications. Lower extremity strength was assessed after anesthesia and in the intensive care unit. A loss of lower extremity somatosensory evoked potential or lower extremity strength was treated emergently to maintain a mean arterial pressure 90 mmHg or greater and a cerebrospinal fluid pressure 10 mm Hg or less.

RESULTS

Seventy-five patients (male = 49, female = 26, age = 75 +/- 7.4 years) had descending thoracic aortic aneurysms repaired with endovascular stenting. Lumbar cerebrospinal fluid drainage (n = 23) and somatosensory evoked potential monitoring (n = 15) were performed selectively in patients with significant aneurysm extent or with prior abdominal aortic aneurysm repair (n = 17). Spinal cord ischemia occurred in 5 patients (6.6%); two had lower extremity somatosensory evoked potential loss after stent deployment and 4 developed delayed-onset paraplegia. Two had full recovery in response to arterial pressure augmentation alone. Two had full recovery and one had near-complete recovery in response to arterial pressure augmentation and cerebrospinal fluid drainage. Spinal cord ischemia was associated with retroperitoneal bleed (n = 1), prior abdominal aortic aneurysm repair (n = 2), iliac artery injury (n = 1), and atheroembolism (n = 1).

CONCLUSIONS

Early detection and intervention to augment spinal cord perfusion pressure was effective for decreasing the magnitude of injury or preventing permanent paraplegia from spinal cord ischemia after endovascular stent repair of descending thoracic aortic aneurysm. Routine somatosensory evoked potential monitoring, serial neurologic assessment, arterial pressure augmentation, and cerebrospinal fluid drainage may benefit patients at risk for paraplegia.

Long-term results of endoluminal grafting for descending thoracic aortic aneurysms

OBJECTIVE

This paper describes the long-term results of endoluminal grafting (EG) for the treatment of descending thoracic aortic aneurysms (dTAA).

METHODS

Until July 2004, EG for dTAA has been applied in 45 cases (male/female, 29/16, 49-86 years old, mean age 67 years old). Locations included the proximal dTAA in 24 cases, and middle or distal dTAA in 21 cases. The stent-grafts (SGs) were constructed of Gianturco Z-stents covered with woven polyester grafts.

RESULTS

Deployment of the SGs was successful in 43 of 45 cases (96%) and complete thrombosis of the aneurysm was achieved in 39 cases (87%). Six minor endoleaks (13%), one migration (2%) and one conversion to surgery (2%) occurred. There was no instance of paraplegia nor hospital death. Over a mean 48 month follow-up (range 3 to 90), there were three persistent endoleaks (6%), four secondary endoleaks (8%), one breakage of wire frame (2%). Four cases were converted to open surgery due to secondary endoleak. There were two aneurysmal ruptures at the site where EG was not performed. The cumulative survival rate was 95.6 +/- 4.4% at 12 months, 85.7 +/- 5.4% at 24 months, and 82.4 +/- 6.1% at 36 and 60 months.

CONCLUSION

These results demonstrated that EG is safe and effective in selected dTAA patients. Improvements in patients selection, surgical techniques and equipment will reduce EG related complications and conversion to open repair over the course of the evaluation.

Clinical application of a curved nitinol stent-graft for thoracic aortic aneurysms

PURPOSE

To evaluate the clinical efficacy of a curved nitinol stent-graft for repair of thoracic aortic aneurysms.

METHODS

The Matsui-Kitamura stent-graft (MKSG), composed of a self-expanding nitinol stent and polyester fabric, was shaped to match the aortic curvature of 11 patients (6 men; mean age 72.6 years, range 33-90) with 6 true and 5 false aneurysms of the distal arch or proximal descending aorta. The delivery system was an 18 or 20-F J-shaped sheath combined with a preloader-type introducer. The original mean proximal neck length was 16.4 mm, but 4 patients received an axilloaxillary bypass to lengthen the neck. Although the mean corrected proximal neck length was 21.9 mm (overall), 5 cases still had proximal necks <15 mm long.

RESULTS

All curved MKSGs were successfully deployed in the correct position and fitted to the curvature of the aortic arch, achieving complete aneurysm exclusion in 8 (73%) cases. The other 3 repairs displayed early endoleaks; 1 received an additional MKSG, but the other 2 are being observed. Thirty-day mortality was 0%. One patient developed transient renal failure requiring hemodialysis; no neurological complications were observed.

CONCLUSIONS

Endovascular repair of thoracic aortic aneurysms using curved MKSGs appears to be feasible and clinically effective. A tighter fit of the device to the curvature of the aortic arch may exclude distal arch aneurysms despite a short proximal neck.