Transesophageal Ultrasound Guidance for Endovascular Interventions on the Aorta

Anesthetic Considerations for Endovascular Repair of the Thoracic Aorta

Thoracic aorta pathologies, especially those of the ascending aorta and aortic arch, were traditionally approached via open surgical repair. This carries risk of ischemic end-organ damage and other complications. Endovascular repair of ascending aorta and aortic arch pathologies is becoming more successful and widespread, thereby posing numerous challenges to the anesthesiologist. This article reviews the anesthesia-pertinent pathophysiology, repair techniques, preoperative evaluation, intraoperative management, and postoperative care of patients presenting for endovascular repair of thoracic aorta pathologies.

Endovascular Technique for Ascending Aorta Repair Based on TEVAR and TAVI Procedures

PURPOSE

Ascending aorta (AAo) acute pathology still has an open-surgery indication with a high mortality rate associated to cardiopulmonary bypass and circulatory arrest. In these cases, the endovascular aortic approach could be an excellent option. The aim of the present study is to detail an optimized technique for the endovascular treatment of AAo diseases, based on thoracic endovascular aortic repair (TEVAR) and transcatheter aortic valve implantation (TAVI) procedures.

TECHNIQUE

The procedure implies the usual preparation for TEVAR and TAVI implants. A transient pacemaker lead is necessary to deliver the prosthesis under "rapid pacing." As in the TAVI technique, a final high-support guidewire is placed at the left ventricle. The proximal landing zone is the sinotubular junction (zone 0B). Transesophageal echocardiography is essential to ensure aortic valve function and patency in coronary arteries during the delivery. To assess a potential occlusion of the brachiocephalic artery, a guidewire is positioned in the descending aorta from the axillary artery. Finally, a noncovered stent is implanted to stabilize the AAo prosthesis.

CONCLUSION

The technique presented here can standardize a safe and reproducible procedure to endovascular repair of AAo diseases. However, new devices specifically designed for the AAo could facilitate the transcatheter approach.

CLINICAL IMPACT

Ascending aorta acute pathology still has an open-surgery indication with high mortality rate associated to cardiopulmonary bypass and circulatory arrest. Moreover, near 30% of patients are not considered suitable for surgery because of age, critical situation or the presence of severe comorbidities. The present study provides a detailed and optimized technique for the endovascular treatment of ascending aorta disease, based on TEVAR and TAVI procedures.

How Would I Treat My Own Thoracoabdominal Aortic Aneurysm: Perioperative Considerations From the Anesthesiologist Perspective

A thoracoabdominal aortic aneurysm (TAAA) can be potentially life-threatening due to its associated risk of rupture. Thoracoabdominal aortic aneurysm repair, performed as endovascular repair and/or open surgery, is the recommended therapy of choice. Hemodynamic instability, severe blood loss, and spinal cord or cerebral ischemia are some potential hazards the perioperative team has to face during these procedures. Therefore, preoperative risk assessment and intraoperative anesthesia management addressing these potential hazards are essential to improving patients' outcomes. Based on a presented index case, an overview focusing on anesthetic measures to identify perioperatively and manage these risks in TAAA repair is provided.

A Case Report of Aortic Intramural Hematoma: From Diagnosis to Endovascular Treatment Guided by Transesophageal Echocardiography

Aortic intramural hematoma (IMH) accounts for approximately 10%-25% of acute aortic syndromes (AAS), and multi-slice computed tomography and magnetic resonance imaging are the leading techniques for diagnosis and classification. In this context, endovascular strategies provide a valid alternative to traditional open surgery and transesophageal echocardiography (TEE) could play a role in therapeutic decision-making and in endovascular repair procedure guidance. A 57-year-old female patient with IMH extending from the left subclavian artery to the upper tract of the abdominal aorta, underwent endovascular aortic repair using an unibody single-branched stent grafting in the aortic arch and descending aorta with a side branch inserted in the left common carotid artery. To restore proper flow in the left axillary artery, a carotid-subclavian bypass graft was performed. The procedure was guided by angiography and TEE. Intraoperative TEE revealed aortic IMH with a significant fluid component in the middle tunic of the aorta with a wall thickness of over 13 mm. TEE was useful in monitoring of all steps of the procedure, showing the presence of the guidewires into the true lumen, the advancement of the prosthesis, and the phases of release and anchoring. This case highlights the importance of using multimodality imaging techniques to evaluate AAS and demonstrates the growing potential of TEE in guiding endovascular repairs.

Acute Aortic Syndromes from Diagnosis to Treatment-A Comprehensive Review

This work aims to provide a comprehensive description of the characteristics of a group of acute aortic diseases that are all potentially life-threatening and are collectively referred to as acute aortic syndromes (AASs). There have been recent developments in the care and diagnostic plan for AAS. A substantial clinical index of suspicion is required to identify AASs before irreversible fatal consequences arise because of their indefinite symptoms and physical indicators. A methodical approach to the diagnosis of AAS is addressed. Timely and suitable therapy should be started immediately after diagnosis. Improving clinical outcomes requires centralising patients with AAS in high-volume centres with high-volume surgeons. Consequently, the management of these patients benefits from the increased use of aortic centres, multidisciplinary teams and an "aorta code". Each acute aortic entity requires a different patient treatment strategy; these are outlined below. Finally, numerous preventive strategies for AAS are discussed. The keys to good results are early diagnosis, understanding the natural history of these disorders and, where necessary, prompt surgical intervention. It is important to keep in mind that chest pain does not necessarily correspond with coronary heart disease and to be alert to the possible existence of aortic diseases because once antiplatelet drugs are administered, a blocked coagulation system can complicate aortic surgery and affect prognosis. The management of AAS in "aortic centres" improves long-term outcomes and decreases mortality rates.

Three-Dimensional Transesophageal Echocardiography in Percutaneous Catheter-Based Cardiac Interventions

Cardiac structural and valve interventions have remained surgical procedures for several decades. The ability to directly visualize the region of interest during surgery made imaging of these structures pre- and postsurgery a secondary tool to compliment surgical visualization. The last two decades, however, have seen rapid advances in catheter-based percutaneous structural heart interventions (SHIs). Due to the "blind" nature of these interventions, imaging plays a crucial role in the success of these procedures. Fluoroscopy is used universally in all percutaneous cardiac SHIs and helps primarily in the visualization of catheters and devices. However, success of these procedures requires visualization of intracardiac soft tissue structures. Due to its portable nature and rapid ability to show cardiac structures online, transesophageal echocardiography (TEE) has become an integral tool for guidance for all percutaneous SHI. Transcatheter aortic valve replacement-one of the earliest catheter-based procedures-while initially dependent on TEE, has largely been replaced by preprocedural cardiac CT for accurate assessment of valve sizing. Developments in echocardiography now allow live three-dimensional (3D) visualization of cardiac structures mimicking surgical anatomy during TEE. Besides showing actual 3D intracardiac structures, 3D-TEE allows visualization of the interaction of intracardiac catheters and devices with soft tissue cardiac structures, thereby becoming a "second pair of eyes" for the operator. Real-time 3D-TEE now plays an important role complementing multiplane two dimensional and biplane TEE during such interventions. In this review, we discuss the incremental role of 3D-TEE during various SHIs performed today.

A Case of Type B Aortic Dissection: The Role of Transesophageal Ultrasound Guidance in Thoracic Endovascular Aortic Repair

Thoracic endovascular aortic repair (TEVAR) plays a central role in managing acute and chronic aortic pathologies. With the advancement of transcatheter structural heart procedures, echocardiography has become a key in procedural guidance. Despite consensus on its use for cardiac interventions, ultrasound assistance in aortic procedures is not widely standardized. A 71-year-old obese man with chronic type B aortic dissection underwent a TEVAR procedure, using a single-branched aortic stent graft (Endovastec™ Castor™) and with transesophageal ultrasound guidance. The preprocedural assessment confirmed the presence of aortic dissection of the descending thoracic aorta with a posterior true lumen (TL) and an anterior false lumen (FL), normal aortic valve anatomy and function, normal left ventricular function, absence of intracavity thrombus, and absence of aortic plaques that could prevent the optimal implantation of the stent graft. During the procedure, a transesophageal echocardiogram (TEE) monitored the positioning of the guide wires, the arrival of the catheter of the thoracic endoprosthesis, and then the implantation of this at the level of the aortic arch and the descending thoracic aorta. Postprocedure TEE evaluation underlined full stent-graft deployment without leaks and successful exclusion of FL with the beginning of thrombosis. Angiography confirms the exclusion of the aneurysm and the absence of endoleaks. This clinical case demonstrates how transesophageal echocardiographic guidance can improve the TEVAR procedure by minimizing fluoroscopy time, contrast medium use, and enabling a better assessment of the dissection anatomy with real-time monitoring of both the TL and the FL. In conclusion, TEE can serve as an auxiliary intraoperative imaging tool to provide good information before, during, and after the procedure, increasing the success and safety of the TEVAR.

Current Understanding of Aortic Dissection

The aorta is the largest artery in the body, delivering oxygenated blood from the left ventricle to all organs. Dissection of the aorta is a lethal condition caused by a tear in the intimal layer of the aorta, followed by blood loss within the aortic wall and separation of the layers to full dissection. The aorta can be affected by a wide range of causes including acute conditions such as trauma and mechanical damage; and genetic conditions such as arterial hypertension, dyslipidaemia, and connective tissue disorders; all increasing the risk of dissection. Both rapid diagnostic recognition and advanced multidisciplinary treatment are critical in managing aortic dissection patients. The treatment depends on the severity and location of the dissection. Open surgical repair is the gold standard of treatment for dissections located to the proximal part of the aorta and the arch, while endovascular interventions are recommended for most distal or type B aortic dissections. In this review article, we examine the epidemiology, pathophysiology, contemporary diagnoses, and management of aortic dissection.