Journal of Vascular Medicine & Surgery

Spinal Cord Ischemia Prevention in Thoracoabdominal Aortic Aneurysm Repair: The Role of Temporary Aneurysm Sac Perfusion

Houssam Farres^* and Yaman Alsabbagh Department of Vascular and Endovascular Surgery, Mayo Clinic, Florida, USA
^*Correspondence: Houssam Farres, Department of Vascular and Endovascular Surgery, Mayo Clinic, Florida, USA, Email:

Received: 12-Jul-2024, Manuscript No. JVMS-24-26488; Editor assigned: 16-Jul-2024, Pre QC No. JVMS-24-26488 (PQ); Reviewed: 30-Jul-2024, QC No. JVMS-24-26488; Revised: 06-Aug-2024, Manuscript No. JVMS-24-26488 (R); Published: 13-Aug-2024, DOI: 10.35248/2329-6925.24.12.566

Description

The prevention of Spinal Cord Ischemia (SCI) remains a critical challenge in the management of Thoracoabdominal Aortic Aneurysms (TAAA). SCI can lead to paralysis, significantly impacting patient outcomes and decreasing their quality of life [1]. The pathophysiology of SCI is complex and not fully understood, but it is more common in type II TAAA and open repair [2]. This increased risk is often due to aortic clamping during open repair, which impedes the blood supply to the spinal cord [3].

Several strategies have been used to mitigate the incidence of SCI, including Cerebrospinal Fluid (CSF) drainage and permissive hypertension. Both strategies aim to improve Spinal Cord Perfusion Pressure (SCPP), which is the difference between blood pressure and CSF pressure, with the goal of maintaining an SCPP of at least 60 mmHg. CSF drainage aims to increase SCPP by maintaining CSF pressure below 15 mmHg in the perioperative period [4]. However, it is associated with several complications, such as infection, subarachnoid bleeding, spinal headaches, and spinal hematoma [5]. Permissive hypertension involves maintaining a mean arterial pressure of ≥ 70 mmHg, which can also improve SCPP [6].

With the increasing use of endovascular techniques in TAAA repair, these traditional strategies have become less popular. The complications associated with CSF drainage and its limited role in decreasing the SCI rates after Thoracic Endovascular Aortic Repair (TEVAR) necessitate new strategies to mitigate SCI risk while minimizing complications associated with spinal drain placement [7-9]. Furthermore, delayed paraplegia can occur within 72 hours postoperatively due to the failure of the existing spinal collateral networks to maintain adequate perfusion. Despite this risk, spinal drains are rarely maintained beyond this period [6,10]. Staging the repair by at least five days is another strategy that has been employed in both endovascular and open repairs. This strategy creates a metabolic demand and oxygen delivery mismatch by the gradual decrease in the blood supply to the spinal cord, promoting the development of new spinal collateral networks [11]. In endovascular repair, a two or morestage approach is often used, commonly with an interval of one week to several months [12]. Minimally Invasive Segmental Artery Coil Embolization (MISACE) can be performed before the thoracic repair to precondition the spinal circulation through the same mechanism [13]. A hybrid approach, combining open and endovascular techniques, has been suggested to decrease morbidity and mortality. This can be achieved by performing abdominal aorta debranching of the mesenteric and renal arteries, followed by total exclusion of the aneurysmal aorta [14].

Temporary Aneurysm Sac Perfusion (TASP) is a newly adopted technique in staged endovascular TAAA repair. The theory behind TASP is to create a metabolic demand and oxygen delivery mismatch in spinal cord perfusion, inducing a state of reversible ischemia. This promotes the development of new spinal collateral networks [11]. This can be achieved by leaving an intentional type 1b/c endoleak through the delayed insertion of bridging and/or iliac limbs or by leaving a bare stent in one of the visceral branches. Our literature review found that following endovascular TAAA repair, 40 out of 479 patients developed temporary SCI and 10 developed permanent SCI, supporting the benefit of this technique in SCI prevention. TASP is seldom applied in hybrid repair. We successfully employed this technique using a hybrid approach (Figure 1), preventing SCI without creating any additional complications [15]. Incorporating intraoperative neuromonitoring can further assist in decision-making regarding the utilization of TASP [16].

Figure 1: Illustration of hybrid Thoracoabdominal Aortic Aneurysm (TAAA) repair. 1) Abdominal aorta debranching of the mesenteric and renal arteries; 2) Endovascular thoracoabdominal aneurysm repair, leaving the left iliac limb unbridged to allow for Temporary Aortic Aneurysm Perfusion (TASP); 3) Complete exclusion of the aneurysm.

Applying TASP can be limited to certain populations due to specific risks. Leaving the aneurysm sac unexcluded to promote the development of spinal collateral networks carries the potential risk of interval aneurysm rupture. This risk is particularly pronounced in aneurysms larger than 7.5 cm in diameter. Consequently, it is recommended to perform a singlestage repair for TAAAs >7 cm [17].

Future research may be warranted to optimize TASP protocols, enhancing both its efficacy and safety. Studies comparing different methods of the best approach to create TASP and the timing of the staged procedures would provide valuable insights. Additionally, research exploring the long-term outcomes of patients treated with TASP, including quality of life and neurological function, would help to establish its role in standard clinical practice.

Conclusion

Preventing SCI in TAAA repair demands a multifaceted approach, incorporating both traditional and innovative techniques. While CSF drainage and permissive hypertension remain vital, the evolution of endovascular techniques and the introduction of TASP offer new possibilities for improving patient outcomes. Our case underscores the successful application of TASP in a hybrid TAAA repair, demonstrating its feasibility and efficacy in preventing SCI. Future research may be warranted to optimize TASP protocols enhancing both its efficacy and safety.

Funding

This Study was funded by Mayo Clinic, USA.

References

1. Gombert A, Simon F. Strategies to prevent and detect intraoperative spinal cord ischemia during complex aortic surgery: From drainages and biomarkers. Neural Regen Res. 2021;16(4):678-679. 
2. Alzghari T, An RK, Harik L, Rahouma M, Dimagli A, Olaria RP, et al. Spinal cord injury after open and endovascular repair of descending thoracic aneurysm and thoracoabdominal aortic aneurysm: An updated systematic review and meta-analysis. Ann Cardiothorac Surg. 2023;12(5):409-417.
3. Awad H, Ramadan ME, Sayed HFE, Tolpin DA, Tili E, Collard CD, et al. Spinal cord injury after thoracic endovascular aortic aneurysm repair. Can J Anaesth. 2017;64(12):1218-1235.
4. Khan SN, Stansby GP. Cerebrospinal fluid drainage for thoracic and thoracoabdominal aortic aneurysm surgery. Cochrane Database Syst Rev. 2012;10(10):CD003635.
5. Lyden SP, Ahmed A, Steenberge S, Caputo FJ, Smolock CJ, Kirksey L, et al. Spinal drainage complications after aortic surgery. J Vasc Surg. 2021;74(5):1440-1446.
6. Coselli JS, LeMaire SA, Sevilla VO, Preventza O, Moon MR, Barron LM, et al. Current approaches to spinal cord protection during open thoracoabdominal aortic aneurysm repair. Ann Cardiothorac Surg. 2023;12(5):429-437.
7. Frankort J, Mees B, Doukas P, Keszei A, Kontopodis N, Antoniou GA, et al. Systematic review of the effect of cerebrospinal fluid drainage on outcomes after endovascular descending thoracic/thoraco-abdominal aortic aneurysm repair. Eur J Vasc Endovasc Surg. 2023;66(4):501-512.
8. Locatelli F, Nana P, Houérou TL, Guirimand A, Nader M, Gaudin A, et al. Spinal cord ischemia rates and prophylactic spinal drainage in patients treated with fenestrated/branched endovascular repair for thoracoabdominal aneurysms. J Vasc Surg. 2023;78(4):883-891.
9. Youngblood SC, Tolpin DA, LeMaire SA, Coselli JS, Lee VV, Cooper JR, et al. Complications of cerebrospinal fluid drainage after thoracic aortic surgery: A review of 504 patients over 5 years. J Thorac Cardiovasc Surg. 2013;146(1):166-171.
10. Simon MV, Dong CC, Jacobs MJ, Mess WH. Neuromonitoring during descending aorta procedures. Handb Clin Neurol. 2022;186:407-431.
11. Carroll AM, King RW, Ghincea CV, Aftab M, Reece TB. Spinal cord protection for thoracoabdominal aortic aneurysm repair: From bench to bedside. Ann Cardiothorac Surg. 2023;12(5):438-449.
12. Muston BT, Bilbrough J, Bushati Y, Smith ARW, Misfeld M, Yan T, et al. Open, closed or a bit of both: A systematic review and meta-analysis of staged thoraco-abdominal aortic aneurysm repair. Ann Cardiothorac Surg. 2023;12(5):418-428.
13. Marturano F, Nisi F, Giustiniano E, Benedetto F, Piccioni F, Ripani U, et al. Prevention of spinal cord injury during thoracoabdominal aortic aneurysms repair: What the anaesthesiologist should know. J Pers Med. 2022;12(10):1629.
14. Tanaka A, Oderich GS, Estrera AL. Total abdominal debranching hybrid thoracoabdominal aortic aneurysm repair versus chimneys and snorkels. JTCVS Tech. 2021;10:28-33.
15. Alsabbagh Y, Erben Y, Lanka SP, Mahajan B, Farres H. Temporary aneurysm sac perfusion following hybrid thoracic abdominal Aortic aneurysm repair and literature review. Ann. Vasc. Surg. 2024; 4(2):100281.

    [Crossref] [Google Scholar]

16. Tenorio ER, Neto MFD, Lima GB, Estrera AL, Oderich GS. Endovascular repair for thoracoabdominal aortic aneurysms: Current status and future challenges. Ann Cardiothorac Surg. 2021;10(6):744-767.

    [Crossref] [Google Scholar] [PubMed]

17. Penn NCC, Mendes BC, Tenorio ER, Monson LCC, Oria MD, Oderich GS, et al. Incidence and risk factors for interval aortic events during staged fenestrated-branched endovascular aortic repair. J Vasc Surg. 2023;78(4):874-82.

    [Crossref] [Google Scholar] [PubMed]