Evaluation of the vertebrobasilar system in thoracic aortic surgery

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.

Cannulation strategies in type A aortic dissection: a novel insight narrative review

This review highlights vital details that can be easily overlooked and discuss how to identify and fix failed cannulation from another novel insight. Appropriate arterial cannulation strategy during cardiopulmonary bypass (CPB) in Stanford type A aortic dissection (AAD) is highly necessary to reach satisfactory perfusion effects and appreciable clinical outcomes. Despite several previously published reviews on cannulation strategies in AAD, most focus on the advantages and disadvantages by comparing various cannulation strategies. In fact, most of evidence came from retrospective studies. More importantly, however, some important details and novel approaches maybe overlooked due to variety reasons. These overlooked details also make sense in clinical practice. Papers related to cannulation refer to type AAD were retrieved and analyzed from the PubMed and Medline database. The key words such as “aortic dissection”, “cannula”, “cannulation”, “cannulation strategy”, “cerebral perfusion”, “type I aortic dissection” were conducted and analyzed. In addition, we looked at some new and very significant specific perfusion techniques such as anterograde cerebral perfusion combined with retrograde inferior vena caval perfusion (RIVP) and reperfusion via the right carotid artery before surgery. The arterial cannulation site and strategy should be determined individually. Monitoring measures are very necessary in the whole procedure.

Endovascular Repair of an Aortic Arch Aneurysm in a Patient with a Hypoplastic Left Vertebral Artery Terminating into the Posterior Inferior Cerebellar Artery

We present a 76-year-old male with an aortic arch aneurysm and a hypoplastic left vertebral artery (VA). Endovascular repair with left subclavian artery (SCA) closure was planned. The right VA was dominant, while the left VA was hypoplastic, barely connected to the basilar artery, and appeared to terminate at the posterior inferior cerebellar artery (PICA). The VA sizes and flow patterns during ultrasonography confirmed these findings. Therefore, we performed endovascular repair with left SCA reconstruction to prevent ischemia of the PICA perfusion area. After the operation, he experienced no difficulty with brain perfusion.

Transposition of the left vertebral artery during endovascular stent-graft repair of the aortic arch

OBJECTIVES

The aim of this study was to present our experience with the management of isolated left vertebral artery during hybrid aortic arch repairs with thoracic endovascular aortic repair completion.

METHODS

This is a single-center, observational, cohort study. Between January 2007 and December 2018, 9 patients (4.5%) of 200 who underwent thoracic endovascular aortic repair were identified with isolated left vertebral artery. The isolated left vertebral artery was the dominant vertebral artery in 4 cases and entered the Circle of Willis to form the basilar artery in all cases. Isolated left vertebral artery transposition was performed in 2 patients during open ascending/arch repair before thoracic endovascular aortic repair completion. In 4 patients, isolated left vertebral artery transposition was performed concomitant with carotid-subclavian bypass during thoracic endovascular aortic repair completion ("zone 2" thoracic endovascular aortic repair). Primary outcomes were early (<30 days) and late survival, freedom from aortic-related mortality, and isolated left vertebral artery patency.

RESULTS

Primary technical success was achieved in all cases. Isolated left vertebral artery-related complication occurred in 1 patient (Horner syndrome). Immediate thrombosis, vagus/recurrent laryngeal nerve palsy, lymphocele, and chylothorax were never observed. Postoperative cerebrovascular accident or spinal cord injury was not observed. Median follow-up was 15 months (range, 3-72). We did not observe aortic-related mortality during the follow-up. Aortic-related intervention was never required. Both isolated left vertebral artery and carotid-subclavian bypass are still patent in all patients with no sign of anastomotic pseudoaneurysm or stenosis.

CONCLUSIONS

Although isolated left vertebral artery is not a frequent occurrence, it is not so rare. It may pose additional difficulties during hybrid aortic arch surgical repairs, but isolated left vertebral artery transposition was feasible, safe, and a durable reconstruction.

Early Experiences with the Endovascular Repair of Ruptured Descending Thoracic Aortic Aneurysm

BACKGROUND

The aim of this study was to report our early experiences with the endovascular repair of ruptured descending thoracic aortic aneurysms (rDTAAs), which are a rare and life-threatening condition.

METHODS

Among 42 patients who underwent thoracic endovascular aortic repair (TEVAR) between October 2010 and September 2015, five patients (11.9%) suffered an rDTAA.

RESULTS

The mean age was 72.4±5.1 years, and all patients were male. Hemoptysis and hemothorax were present in three (60%) and two (40%) patients, respectively. Hypovolemic shock was noted in three patients who underwent emergency operations. A hybrid operation was performed in three patients. The mean operative time was 269.8±72.3 minutes. The mean total length of aortic coverage was 186.0±49.2 mm. No 30-day mortality occurred. Stroke, delirium, and atrial fibrillation were observed in one patient each. Paraplegia did not occur. Endoleak was found in two patients (40%), one of whom underwent an early and successful reintervention. During the mean follow-up period of 16.8±14.8 months, two patients died; one cause of death was a persistent type 1 endoleak and the other cause was unknown.

CONCLUSION

TEVAR for rDTAA was associated with favorable early mortality and morbidity outcomes. However, early reintervention should be considered if persistent endoleak occurs.

Vertebral artery variations in thoracic aortic patients

OBJECTIVES

Arterial variation is common in the vertebral artery, and simple occlusion of the left subclavian artery may result in brain infarction, especially when it terminates in the posterior inferior cerebellar artery (PICA). We report the results of preoperative vertebral artery evaluation by magnetic resonance angiography (MRA) and its impact upon operative strategy.

METHODS

Among the 214 patients who underwent thoracic aortic surgery from 2009 through 2012, 159 patients with preoperative MRA were retrospectively analysed. Patients' age ranged from 35 to 88 (median 72), 122 were male and 115 had degenerative aneurysms. Prevalence rates of vertebral artery variations and occlusive lesions were reported, together with operative strategies and outcomes.

RESULTS

There were 19 hypoplasia (12%), 10 PICA termination (6%) and 12 occlusive lesion (8%) on the right vertebral artery and 10 hypoplasia (6%), 5 PICA termination (3%), 7 direct arch origin (4%) and 3 occlusive lesion (2%) on the left. Two of the seven arch-originated arteries terminated in the PICA. In aortic arch replacement, these were reconstructed together with the left subclavian artery while hypothermia was maintained. During thoracic endovascular aortic repair with Zone-2 proximal landing, debranching bypass was employed to preserve left subclavian perfusion when there was PICA termination, hypoplasia or occlusive lesion. In 1 patient with hypoplasia between the basilar artery and the left PICA, bypass was added immediately after deployment because radial pressure dropped critically. No brain infarction occurred with this strategy.

CONCLUSIONS

PICA termination and right side hypoplasia/occlusive lesion, where left subclavian perfusion is important for brain protection, is present in ∼ 30%. Left vertebral artery that originated from the arch should be managed with care, because PICA termination is highly prevalent.

Total arch replacement in a patient with an unusual vascular anatomy

A 69-year-old man with a history of infectious abdominal aortic aneurysm, which had resulted in removal of the infrarenal abdominal aorta and bilateral axillofemoral bypass 9 years previously, underwent total arch replacement for an aortic arch aneurysm. The patient had the interrupted abdominal aorta and highly atherosclerotic proximal aorta, which precluded the possibility of endovascular stent grafting in combination with arch vessel debranching technique. Therefore, open arch repair was the only treatment option. The operation was successful with his axillofemoral bypass graft being exposed and used for arterial inflow during cardiopulmonary bypass, including integrated selective antegrade cerebral perfusion.