Endangered Cerebral Blood Supply After Closure of Left Subclavian Artery: Postmortem and Clinical Imaging Studies

Transposition of Anomalous Left Vertebral to Carotid Artery During the Management of Thoracic Aortic Dissections and Aneurysms

OBJECTIVES

Preservation of antegrade flow to the left vertebral artery is often achieved by transposition or bypass to the left subclavian artery during zone 2 thoracic endovascular aortic repair (TEVAR). An anomalous left vertebral artery (aLVA) originating directly from the aortic arch is a common arch variant with a reported incidence of 4-6%. In addition, 6-10% of vertebral arteries terminate in a posterior inferior cerebellar artery (PICA), increasing the risk of stroke if not revascularized. Few series of aLVA to carotid transposition have been reported. The aim of this study was to evaluate the outcomes of patients who underwent aLVA to carotid transposition for the management of aortic disease.

METHODS

A retrospective review of all aLVA-carotid transpositions performed for the management of thoracic aortic dissection or aneurysm at a single center from 2018 to 2021 was performed. The primary outcomes were postoperative stroke and patency of the transposed aLVA. Secondary outcomes were spinal cord ischemia, postoperative cranial nerve injury (CNI), and Horner's syndrome.

RESULTS

Seventeen patients underwent aLVA to carotid transposition as an adjunct to management of aortic disease during the study period. Most were men (14) and the mean age was 54 (±16 years). The primary indication for aortic repair was dissection in 10, aneurysm in 6, and Kommerell diverticulum in 1. Nine patients underwent zone 2 TEVAR, seven received open total arch repair and there was one attempted total endovascular arch repair which was aborted due to unfavorable anatomy. Twelve transpositions were performed prior to or concomitant with planned aortic repair due to high-risk cerebrovascular anatomy (3 PICA termination, 6 dominant aLVA, 4 intracranial left vertebral artery stenosis), and two were performed postoperatively for treatment of type II endoleak. LVA diameter ranged from 2 - 6mm (mean 3.3 mm). Mean operative time for transposition was 178 (±38) minutes, inclusive of left subclavian artery revascularization and mean estimated blood loss was 169 (±188) mL. No patients experienced 30-day postoperative spinal cord ischemia, stroke, or mortality. There were two cases of postoperative hoarseness, presumably due to recurrent laryngeal nerve palsy, both of which resolved within 4 months. There were no cases of Horner's syndrome. At follow-up (mean 306 days [6-714 days]), all transpositions were patent.

CONCLUSIONS

Vertebral-carotid transposition is a safe and effective adjunct in the management of aortic disease with anomalous origin of the LVA.

Isolated left vertebral artery and its consequences for aortic arch repair

A left vertebral artery (LVA) originating directly from the aortic arch is the second most common supra-aortic branching anomaly. This isolated LVA can also terminate in the posterior inferior cerebellar artery without contributing to the circle of Willis, limiting treatment options, especially in cases with an incomplete circle. Here, we describe our consideration of the treatment options for a 79-year-old patient with a large distal aortic arch aneurysm combined with an isolated LVA and incomplete circle of Willis that may endanger adequate (intraoperative) cerebral perfusion.

Aortic arch aneurysm repair using the Najuta stent graft in a challenging compromised seal zone

We report the case of a 67-year-old patient with an anatomically complex aneurysm of the aortic arch treated by fenestrated thoracic endovascular aortic repair with subclavian-carotid extrathoracic bypass. We used the Najuta thoracic stent graft, which was approved for use in January 2013 in Japan and successfully excluded the aneurysm. Our case shows that the Najuta stent graft procedure is a feasible treatment if open repair is unsuitable for cases of aortic arch aneurysm with a challenging compromised seal zone.

One-stage hybrid procedure without sternotomy for treating thoracic aortic pathologies that involve distal aortic arch: a single-center preliminary study

OBJECTIVE

This study aims to evaluate the initial results of a hybrid procedure without sternotomy for treating descending thoracic aortic disease that involves distal aortic arch. It also intends to report our initial experience in performing this procedure.

METHODS

A total of 45 patients (35 males and 10 females) with descending thoracic aortic disease underwent a hybrid procedure, namely, thoracic endovascular aortic repair (TEVAR) combined with supra-arch branch vessel bypass, in our center from April 2009 to August 2014. Right axillary artery to left axillary artery bypass (n=20) or right axillary artery to left common carotid artery (LCCA) and left axillary artery bypass (n=25) were performed. The conditions of all patients were followed up from the 2(nd) month to the 65(th) month postoperative (mean, 26.0±17.1). Mortality within 30 days, complications such as endoleak after the hybrid procedure, and stenosis or blockage of the bypass graft during the follow-up period was assessed.

RESULTS

All the patients underwent a one-stage procedure. One case of death and one case of cerebral infarction were reported within 30 days. One patient died of the sudden drop in blood pressure during the 2(nd) day of operation. Meanwhile, another patient suffered from cerebral infarction. Two patients underwent open surgery, and one of them had to undergo a second TEVAR during the follow-up period. Moreover, endoleak occurred in two patients and a newly formed intimal tear was observed in one patient. Overall, 93.2% of the patients survived without any complication related to the hybrid procedure.

CONCLUSIONS

Initial results suggest that the one-stage hybrid procedure is a suitable therapeutic option for thoracic aortic pathologies that involve distal aortic arch. However, this procedure is not recommended for type-B aortic dissection, in which a tear is located in the greater curvature or near the left subclavian artery (LSA), because of the high possibility of endoleak occurrence.

The chimney technique for preserving the left subclavian artery in thoracic endovascular aortic repair

OBJECTIVES

The objective of the present study was to evaluate short- and mid-term outcomes of the left subclavian artery (LSA) chimney stent implantation (LSACSI) during thoracic endovascular aortic repair (TEVAR), and to summarize our experience with this technique.

METHODS

From June 2010 to September 2012, 59 patients (49 men; mean age of 57.4 ± 13.3 years, range from 26 to 83 years) who underwent TEVAR and LSACSI were enrolled. Patients suffered from Stanford type B aortic dissection (n = 27), penetrating aortic ulcer (n = 18), aortic arch aneurysm (n = 9), pseudoaneurysm of the aortic arch (n = 4) and proximal type I endoleak after TEVAR of aortic dissection (n = 1). Elective settings were performed in 72% and emergent in 38% of all patients. Follow-up was performed at postoperative 3 months, 6 months and yearly thereafter.

RESULTS

The technical success rate was 98.3% (58/59), and 69 thoracic stent grafts were used. Sixty-two chimney stents, including 55 uncovered and 7 covered stents, were implanted in 59 LSAs. The overall immediate endoleak rate was 15.3% (9/59); type I endoleak was observed in 5 patients and type II in 4 patients. The difference in the immediate endoleak rate related to the anatomy between the outer and the inner curvature was statistically significant (35 vs 4%, P = 0.018). Chimney stent compression was observed in 3 patients and another stent was deployed inside the first one. Perioperative complications included stroke (3.4%, 2/59) and left upper limb ischaemia (1.7%, 1/59). The median follow-up period was 16.5 (range 1–39 months). The mortality rate during follow-up was 5.4% (3/56). Complications during follow-up included endoleak [overall, n = 8 (14.3%, 8/56); type I, n = 5; type II, n = 3], retrograde type A aortic dissection (n = 1), collapse (n = 3, 5.4%) or occlusion (n = 2, 3.6%) of the chimney stent.

CONCLUSIONS

Short- and mid-term results showed that it is feasible to preserve the patency of the LSA in TEVAR with the chimney technique for thoracic aortic pathologies close to the LSA. However, TEVAR combined with LSACSI was not advocated for lesions located at the outer curve of the aortic arch due to a high possibility of endoleak.

How often does an incomplete circle of Willis predispose to cerebral ischemia during closure of carotid artery? Postmortem and clinical imaging studies

PURPOSE

To evaluate the prevalence of anatomical variations in the circle of Willis predisposing to cerebral ischemia during intraoperative closure of a carotid artery.

MATERIALS

Anatomy of the cerebral arteries of 92 deceased was assessed by angiography and permanent silicone casts. Cerebral ischemia during closure of a carotid artery with patent contralateral internal carotid artery (ICA) was considered possible in cases of simultaneous nonfunctioning anterior communicating artery (diameter <0.5 mm) and ipsilateral posterior communicating artery (PComA) (diameter <0.5 mm or fetal type posterior cerebral artery). In cases of contralateral ICA occlusion, cerebral ischemia was considered possible if ipsilateral PComA was nonfunctioning.

RESULTS

Cerebral ischemia during closure of the right or left carotid artery with patent contralateral ICA was estimated to be possible in 16 (17.4%) and 13 (14.1%) cases. In cases of occluded contralateral ICA, the corresponding numbers were 55 (59.8%) and 49 (53.3%). A review of magnetic resonance and catheter angiographies also identified other variants of the circle of Willis with increased risk.

CONCLUSIONS

Incomplete circle of Willis predisposes approximately one-sixth of individuals to cerebral ischemia during transient closure of carotid artery but the risk is more than threefold in case of contralateral ICA occlusion.

Current management of traumatic rupture of the descending thoracic aorta

Traumatic rupture of the descending thoracic aorta remains a leading cause of death following major blunt trauma. Management has evolved from uniformly performing emergent open repair with clamp and sew technique to include open repair with mechanical circulatory support, medical management and most recently, endovascular repair. This latter approach appears, in the short term, to be associated with perhaps better outcome, but long term data is still accruing. While an attractive option, there are specific anatomic and physiologic factors to be considered in each individual case.