Aortic arch replacement for degenerative aneurysms: advances during the last decade

Low-flow perfusion technique for shaggy aortic arch

BACKGROUND

The most common complication of thoracic aortic disease with shaggy aorta is cerebral infarction. We have performed "low-flow perfusion" as a method of extracorporeal circulation to prevent cerebral embolism in patients with strong atherosclerotic lesions in the aortic arch.

METHODS

"Low-flow perfusion" is a method in which cardiopulmonary bypass is started by partial blood removal, approaching deep hypothermia while maintaining self-cardiac output. We compared the outcomes of 12 patients who underwent the "low-flow perfusion" method (Group L) with those of 12 who underwent normal extracorporeal circulation (Group N) during aortic arch surgery since 2019.

RESULTS

Group L consisted of 8 males with an average age of 73 years old, and Group N consisted of 6 males with an average age of 73 years old. The average time from the start of cooling to ventricular fibrillation was 9.5 min in Group L and 3.6 min in Group N (p < 0.01). The eardrum temperature when ventricular fibrillation was reached was 28.2 °C in Group L and 32.5 °C in Group N (p = 0.01). A blood flow analysis also revealed low wall shear stress on the lesser curvature of the aortic arch.

CONCLUSION

With this method, the intracranial temperature was sufficiently low at the time of ventricular fibrillation, and there was no need to increase the total pump flow. The low-flow perfusion method can prevent cerebral embolism by preventing atheroma destruction by the blood flow jet while maintaining the self-cardiac output during the cooling process.

Bilateral Axillary Artery Perfusion in Total Arch Replacement

BACKGROUND

The site of arterial cannulation is an important consideration in the prevention of cerebral infarction after total arch replacement. We compared the outcomes of cannulation of the bilateral axillary artery, the femoral artery, and central cannulation in total arch replacement.

METHODS

Enrolled were 242 patients, categorized into three groups according to the arterial cannulation site used: bilateral axillary artery group, 124 patients; femoral artery group, 88 patients; central cannulation group, 30 patients. Selective cerebral perfusion was used for brain protection in all patients. Surgical outcomes, including the incidence of postoperative cerebral infarction, were compared between the groups.

RESULTS

Cardiopulmonary bypass time and lower-body circulatory arrest time were significantly shorter in the bilateral axillary artery group. Frozen elephant trunk procedure was performed in 54% of the bilateral axillary artery group (P < .001), and concomitant coronary artery bypass graft surgery was performed in 40% of the central cannulation group (P < .01). Hospital mortality in the bilateral axillary artery group was 1.6%, compared with 1.1% in the femoral artery group, and 0% in the central cannulation group (P = .72). The incidence of permanent neurologic deficit was significantly lower in the bilateral axillary artery group (0.8%) than in the central cannulation group (13%; P = .02). Logistic regression analysis indicated that bilateral axillary artery perfusion was a significant factor in the prevention of permanent neurologic deficit (odds ratio 0.10, P = .03).

CONCLUSIONS

Recent technical advances using bilateral axillary artery perfusion and frozen elephant trunk technique were associated with shortening cardiopulmonary bypass time and prevention of postoperative cerebral infarction in total arch replacement.

Redo mitral surgery after coronary artery bypass grafts under hyperkalemic hypothermia using thoracotomy and axillary artery cannulation in a patient with functioning bilateral internal thoracic arteries and atheromatous aorta

BACKGROUND

Redo mitral valve surgery using resternotomy after coronary artery bypass grafting (CABG) is challenging as previous CABG with patent internal thoracic artery (ITA) poses a risk of injury due to dense adhesion. It is paramount to have alternative method to minimize this risk.

CASE PRESENTATION

We report a case of redo mitral and tricuspid valve repair via right thoracotomy under hypothermia and systemic potassium administration with axillary artery cannulation in a patient after CABG with patent bilateral ITA grafts crossing over the sternum. Herein, critical dissection around the aorta and functioning ITA grafts was avoided by performing the procedure under systemic hypothermia via thoracotomy. Furthermore, considering the presence of atheroma in the aorta, the axillary artery was used as a perfusion route to prevent stroke events. Postoperative course was uneventful and echocardiography demonstrated preserved cardiac function.

CONCLUSION

Performing axillary artery cannulation and right thoracotomy under hypothermic cardiac arrest with systemic hyperkalemia without clamping the patent bilateral ITAs and aorta allowed us to perform redo mitral valve surgery after CABG without major postoperative cardiac or cerebral complications.

Impact of the Isolated Cerebral Perfusion Technique for Aortic Arch Aneurysm Repair in Patients with a Shaggy Aorta

Objective: Total aortic arch replacement (TAR), particularly in individuals with extensive atherosclerotic alterations, especially shaggy aortas, is more crucial and difficult. The objective of this retrospective investigation was to ascertain if patients with shaggy aortas would respond to modified isolated cerebral perfusion (ICP). Materials and Methods: Between 2015 and 2020, nine individuals with shaggy aortas who received treatment for arch aneurysms were examined. Four and five patients, respectively, who had arch replacement with traditional selective cerebral perfusion (SCP) and modified ICP, were evaluated, and their short- and long-term results were compared. Results: There were no appreciable variations in the postoperative results between patients with traditional SCP and those with modified ICP. Following surgery, one patient developed paraparesis, while two individuals with traditional SCP experienced persistent neurological damage. In patients with modified ICP, there were no postoperative neurological or other problems associated to atherosclerosis; nevertheless, one patient experienced stroke 5 months after surgery. Conclusion: Patients with shaggy aorta may not receive enough brain protection from TAR with standard SCP because single axillary artery perfusion can result in nonphysiological flow and atheroma separation. Even in patients with shaggy aortas, TAR with modified ICP is safe, but late-phase severe adverse cerebrovascular events should be taken into account.

Functional brain isolation technique for stroke prevention in thoracic endovascular aortic repair

To prevent embolic stroke during thoracic endovascular aortic repair, we have adopted the brain isolation technique since June 2014 in 9 selected high-risk patients (9/134: 6.7%) having ulcerated or protruding atheromas within the proximal aorta. Cardiopulmonary bypass was used to prevent aortic atheromas from entering the brain. We used a heparin-coated closed-loop cardiopulmonary bypass system incorporating a soft reservoir bag with 1 mg/kg heparin to minimize the disadvantages of extracorporeal circulation. The bypass graft (right axillary-left carotid-left axillary) was used as an arterial inflow in patients undergoing zone-1 landing (n = 8), while peripheral cannulation into 3 brachiocephalic arteries was employed in the remaining patient. Initial pump flow was set at 1.3 l/min/m2, and native cardiac output was reduced by adjusting the reservoir bag volume. Aortography was performed to confirm non-visualization of the arch vessels before catheter manipulation. There was no mortality and 1 solitary left cerebellar infarction.

Preoperative renal function affects outcomes of surgery for aortic arch aneurysm in the elderly

OBJECTIVES

This study aimed to determine the optimal surgical procedure for arch aneurysm in the elderly based on preoperative comorbidities, especially focusing on renal function.

METHODS

The medical records of 374 patients who experienced arch surgery between 2008 and 2019 were reviewed. Among the 374 patients, 92 who underwent total arch replacement (TAR) were assigned to the TAR group and the remaining 152 who underwent debranching thoracic endovascular aortic repair (DTEVAR) were assigned to the DTEVAR group.

RESULTS

Chronic kidney disease (CKD) was an independent risk factor of mortality (hazard ratio, 2.85; p = 0.029) in the TAR group but not in the DTEVAR. In the Grade I/II category CKD (estimated glomerular filtration rate (eGFR) > 60 mL/min), freedom from all-cause mortality was significantly higher in the TAR group than in the DTEVAR group (p = 0.0155, log-rank). Freedom from all-cause mortality was comparable between the two groups in the Grade IIIa CKD (eGFR, 45-60) (p = 0.584, log-lank), Grade IIIb (eGFR, 30-45) (p = 0.822), and Grade IV/V (eGFR < 30) (p = 0.548).

CONCLUSION

In elderly patients who underwent TAR, CKD was the independent risk factor of the mortality, but not in the patients who underwent debranching TEVAR. Conversion of surgical strategy from TAR to debranching TEVAR in the treatment of aortic arch aneurysms in the elderly with CKD below Grade IIIa is acceptable considering that less-invasiveness. While, in the elderly with Grade I/II CKD, TAR still remains as a primary choice for the arch repair for better mid-term survival.

Serum Cystatin C Level as a Biomarker of Aortic Plaque in Patients with an Aortic Arch Aneurysm

Aim: During surgery for an aortic arch aneurysm, aortic plaque in the descending aorta should be evaluated, but there are currently no suitable biomarkers for it. Surgeons should be especially aware of cerebral embolism from femoral perfusion and of peripheral embolism from stent graft deployment. Cystatin C is a known useful marker of renal dysfunction with a role as a biomarker for severity of coronary artery disease. In the absence of a suitable biomarker for aortic plaque in the descending aorta, we examine cystatin C as a candidate.

Methods: In all, 75 patients who underwent surgery for an aortic arch aneurysm were enrolled. They were divided into two groups, depending on whether they had chronic kidney disease or not. The serum cystatin C value and creatinine value were evaluated preoperatively. The aortic plaque volume ratio and components in the descending aorta were calculated from preoperative enhanced computed tomography.

Results: The soft plaque volume ratio was higher in patients with chronic kidney disease than in patients without it. Cystatin C positively correlated with the total aortic plaque volume ratio in all cases, and it positively correlated with the soft plaque volume ratio in both groups. Creatinine had no correlation with any type of plaque volume ratio in either group. In patients without chronic kidney disease, the soft plaque volume ratio was higher in patients with higher cystatin C levels than in patients with normal levels.

Conclusion: The preoperative serum cystatin C level could be a biomarker of aortic plaque in the descending aorta in patients with an aortic arch aneurysm.

Total arch replacement for the treatment of a giant protruding thrombus in the thoracic aorta derived from an atherosclerotic lesion

A thoracic aortic thrombus is rare. The causes of this condition and the feasible options for its treatment remain controversial. Preventing embolic complications are the most important for the management of thoracic aortic thrombi. Herein, we report a case of a giant protruding thrombus in the thoracic aorta. We suggest total arch replacement (TAR) using an open stent graft (OSG) as a favorable management technique for thoracic aortic thrombi. We also recommend bilateral axillary artery cannulation to prevent cerebral infarction.

Usefulness of routine use of bilateral axillary artery perfusion in total arch replacement

OBJECTIVES

To avoid cerebral infarction for aortic arch aneurysm and malperfusion for acute aortic dissection, the site of cannulation during total arch replacement remains important. Recently, we have used bilateral axillary artery perfusion in total arch replacement and in acute aortic dissection. Herein, we report the surgical outcomes.

METHODS

Seventy-eight patients with aortic arch aneurysm and 45 patients with acute aortic dissection were enrolled in this study. During surgery, translocation of the total arch was performed on 67 patients using a 'frozen elephant trunk technique'.

RESULTS

In patients with aortic arch aneurysm, there was no postoperative cerebral infarction. New postoperative cerebral infarction was observed in only one patient who underwent acute aortic dissection. Two patients who had aortic arch aneurysm and 2 patients who had acute aortic dissection died at the hospital. Complications related to bilateral axillary perfusion were not observed.

CONCLUSIONS

The routine use of bilateral axillary artery perfusion in total arch replacement for aortic arch aneurysm to avoid cerebral infarction has the potential to be a useful procedure. It can facilitate the frozen elephant trunk procedure in acute aortic dissection.

Modified Isolation Selective Cerebral Perfusion Technique for Intracardiac Disease with Mobile Atheroma

Isolation selective cerebral perfusion (ISCP) technique is reportedly an effective method for preventing brain complications during the treatment of arch aneurysms. Here we present the case of a patient with intracardiac disease complicated by mobile atheroma in the proximal aorta. In this patient, not only the arterial cannulation of the ascending aorta might have posed a high risk of brain stroke but also the original ISCP technique could not be applied. We applied the ISCP technique for non-aortic disease without using circulatory arrest to prevent aortogenic brain embolism. The patients who underwent treatment using this technique were discharged without neurologic complications.

Preventing brain embolism by using a modified isolation technique in transcatheter aortic valve implantation for a patient with shaggy and porcelain aorta

Transcatheter aortic valve implantation (TAVI) has become a useful and effective treatment for surgical high-risk patients with severe aortic valve stenosis (AS). Stroke is one of the most frequent complications associated with TAVI. Shaggy and porcelain aortas are a risk factor for procedure-related strokes. Preventing brain embolism is one of the most important goals in patients with diseased aortas. We present a case where we performed TAVI in an 89-year-old man with severe AS, a shaggy aorta, a porcelain aorta, and congestive heart failure. TAVI via a transfemoral approach was performed using a modified isolation technique with cannulation from bilateral axillary arteries and cardiopulmonary bypass to prevent brain embolism. The catheter-delivered embolic protection device is necessary to pass the diseased aorta, but the modified isolation technique can be used without any contact with the shaggy aorta. Embolism did not occur, and his heart failure improved immediately. <Learning objective: Transcatheter aortic valve implantation (TAVI) is a therapeutic option for patients with severe aortic stenosis considered to be at high risk for aortic valve replacement. Cerebral embolism is the most frequent complication of TAVI. A shaggy or porcelain aorta is associated with a high risk of stroke during TAVI. We report a case of TAVI in a shaggy and porcelain aorta and prevention of cerebral embolism by adopting a modified isolation technique without using conventional protection devices.>.

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.