The Interdisciplinary Aortic Team: Opportunities for Collaboration in Acute Aortic Syndromes

Abstract

Interdisciplinary teams offer potential advantages over siloed care models in complex cardiovascular disease management. Consensus guidelines for aortic management have increasingly identified the interdisciplinary aortic team as a key component in delivering quality care. Acute aortic syndromes are a subset of high acuity and lethal aortic pathologies that may benefit from an interdisciplinary approach. The advantages of the interdisciplinary aortic team model in the management of acute aortic syndromes and barriers to implementation are discussed.

Over the past decade, consensus guidelines throughout cardiovascular medicine have increasingly emphasized the importance of interdisciplinary management of complex diseases. ^{1 2 3 4 5} In structural heart disease, the application of a collaborative approach is incorporated into professional society recommendations such that a multidisciplinary review is required for reimbursement in transcatheter aortic valve replacement. ⁶

Aortic disease consensus guidelines have followed a similar trend, with the most recent American Heart Association guidelines emphasizing that multidisciplinary teams “foster the best treatment of patients, especially for complex presentations with multiorgan threats.” ² In practice, however, the implementation of an aortic team, its composition, and its role in complex aortic disease appears to be variable. ⁷

Can an interdisciplinary approach be adopted for acute aortic syndromes? The most conspicuous barrier is time: the involvement of multiple aortic specialists outside standard operating hours in emergent care is resource-intensive and may be prohibitive in smaller centers. Herein, we suggest opportunities for integrating interdisciplinary teams in the management of acute aortic disease and argue for its adoption in aortic centers.

Defining Team Members

There is no accepted standard for the composition of the interdisciplinary aortic team (IAT). The 2022 ACC/AHA guidelines suggest IAT members should include cardiac surgeons, vascular surgeons, and aortic endovascular specialists; imaging experts facile with CT, MRI, and echocardiography; cardiovascular anesthesiologists; and an intensive care unit familiar with the nuanced care of patients with acute aortic disease. ¹ A joint position statement from the European Association of Cardiothoracic Surgery and the European Society for Vascular Surgery recommended that surgeons should lead an IAT because of their expertise in translating radiographic findings to tissue quality, an important deciding factor between open and endovascular therapy. ⁵ Similarly, the Canadian Consensus Writing Group on the Aortic Team Model recommended core membership comprised of those collectively initiating treatment decisions, recognizing that many other disciplines may be variably involved in a patient's aortic care. ³

Regardless of the exact constituency of the IAT, shared experience and procedural volume between its members are imperative. Increasing evidence suggests that procedural volume correlates with improved outcomes in aortic disease. ^{8 9 10 11} A prevailing motivation for composing an IAT is that a single aortic specialist is unlikely to possess expert-level skills across the breadth of aortic disease management. Thus, a nonhierarchical schema in which specialists synthesize knowledge may be preferred. The Canadian consensus writing group here makes an important distinction between interdisciplinary and multidisciplinary . ³ Multidisciplinarity is additive rather than integrative, and care in a multidisciplinary team often remains specialty-centric, akin to a case conference format in which individuals from different disciplines offer management strategies based on their own experience and expertise. ¹² Interdisciplinary teams instead integrate separate expertise into a single patient-centered consultation. ¹³

The interdisciplinary model also facilitates shared decision-making, another important tenet of the most recent ACC/AHA guidelines. ¹ The IAT is likely better suited to engage a patient in decision-making in scenarios with counterbalancing risks and benefits or complex outcome discussions, particularly when multiple open and endovascular therapies are under consideration.

IAT Approach in Acute Aortic Syndromes

Type A Dissection

Outcomes in acute type A aortic dissection (ATAAD) are improved with the implementation of an aortic team. ^{11 14 15 16 17} Andersen and colleagues described their experience before and after centralizing aortic operations to a high-volume thoracic aortic surgery team, composed of surgeons with advanced training in thoracic aortic operations. Interestingly, an observation from this study was that perioperative outcomes were similar regardless of whether a high-volume aortic surgeon was the primary surgeon or an assistant. ^{16 18}

The relationship between surgical volumes and outcomes also appears to justify the regionalization of aortic care to comprehensive aortic centers. ^{19 20 21} A study of 16,886 Medicare beneficiaries with ATAAD showed a 7.2% absolute risk reduction in operative mortality in high-volume versus low-volume centers. ¹⁹ Time to diagnosis and time from presentation to surgical intervention were observed in another regional system in Minnesota. ²¹ As part of this study, a standardized protocol for regional treatment was developed to provide integrated care for patients with AAD throughout the treatment pathway and involved increasing awareness of AAD among emergency care providers, improving interdisciplinary communication, and providing feedback and quality improvement to core aortic team members. ²¹

Beyond centralization of thoracic aortic surgeons into an aortic team, and regionalization to high-volume aortic centers by way of interhospital transfer, there are specific examples where interdisciplinary teams may benefit ATAAD care. In the 2021 American Association for Thoracic Surgery expert consensus document regarding surgical treatment of ATAAD, the writing group suggested that a team approach may be beneficial when considering treatment options for ATAAD complicated by malperfusion. ²² Endovascular management of malperfusion syndromes, either by a “fenestration-first” or “TEVAR-first” model, may benefit survival compared with traditional strategies. Deeb et al first described the delayed surgical approach in patients with ATAAD and malperfusion syndrome. ²³ Instead of immediate surgical repair, patients first underwent percutaneous fenestration of the dissection flap with selective true lumen branch stenting then stabilized from potential reperfusion injury prior to undergoing proximal repair. Based on a 20-year experience with this endovascular-first approach, Yang and colleagues showed a significantly lower risk of 30-day and in-hospital mortalities relative to expected mortality in an upfront OR approach. ²⁴

At our institution, patients with suspected malperfusion syndrome in ATAAD are evaluated early by an interdisciplinary team. Review of available cross-sectional imaging may occur even before the initiation of interhospital transfer, allowing for appropriate allocation of resources while the patient is en route and activation of the operating room and/or hybrid endovascular room staff. After clinical evaluation by members of the aortic team, a joint decision is then made to proceed with open repair (particularly when the dissection is complicated by tamponade, acute aortic regurgitation, or ST-elevation myocardial infarction) or endovascular management of malperfusion syndrome, typically via fenestration and true lumen stenting. Additional disciplines outside core aortic team members may be consulted as well, such as general surgery when bowel ischemia is suspected.

Type B Dissection

Care pathways in acute type B aortic dissection (ATBAD) are heterogeneous from institution to institution, with multiple disciplines potentially acting as the primary treatment and/or admitting service. In a Canadian survey by McClure and colleagues, ⁷ uncomplicated ATBAD was shown to be admitted to and managed by vascular surgery 37% of the time, by cardiology 31%, by cardiac surgery 18%, and by “other” 7%. “Other” responses included random distribution across multiple specialties based on the first service called, bed availability, or leading role by internal medicine or intensive care providers. Notably, in this same survey, although 89% of respondents felt an aortic team was best for patient care, approximately only half of respondents worked at an institution with an aortic team. A study from the United Kingdom found similar heterogeneity in acute care pathways that continued as an equally variable long-term follow-up, prompting recommendation that all complicated ATBAD be transferred to a specialized unit for treatment by a multidisciplinary team “involving cardiac surgeons, vascular surgeons, interventional radiologists, and intensivists.” ²⁵

An IAT offers several advantages to streamline care in ATBAD. First, a defined admission or transfer pathway avoids nonuniform care between admitting services and obviates the need for additional cross-discipline consultation. Early identification of high-risk and complicating features of ATBAD can also triage patients to optimal care pathways. The most recent Society of Thoracic Surgeons guidelines for the management of TBAD identified several morphologic features posing a risk of later complications, including primary entry tear location at the greater curve of the distal arch, initial total aortic diameter of ≥40 mm, or initial false lumen diameter of ≥22 mm. ²⁶ Cardiovascular radiologists using high-quality imaging tools can expeditiously identify and report high-risk morphology. Finally, operative and procedural strategies for complicated ATBAD necessarily involve endovascular specialists comfortable with aortic endografts and branch vessel revascularization strategies (e.g., fenestration, true-lumen stenting) and surgeons with expertise for arch and descending thoracic operative repair when anatomic factors exclude potential endovascular treatment.

Complex Anatomy: Aortic Arch and Thoracoabdominal Aortic Disease

The complexity of management of dissection or aneurysm involving the aortic arch, and uncertainty in best treatment practices, warrants a team-based approach. In dissection, diverse operative strategies are employed for arch involvement based primarily on the risk of extended aortic arch replacement with the potential benefit of resection of more distal dissected aorta. ^{22 27 28} Tian and colleagues evaluated surgical treatment patterns of ATBAD involving the aortic arch in 151 patients and found comparable early mortality (1.4 vs. 2.2 vs. 3.0%) and 5-year survival (91.1 vs. 90.8 vs. 97.0%) in endovascular repair, hybrid arch repair, and open surgery, respectively. ²⁹ The authors of the study note that multidisciplinary teamwork and experience are “prerequisites for individualized strategies for repair.”

Similarly, the management strategies of thoracoabdominal aortic repair are often discordant, ^{30 31 32} engendering both operative and endovascular repair options, including investigative and novel endovascular techniques. Both the arch and distal descending/thoracoabdominal aorta are aortic segments that may be treated by both cardiac surgery and vascular surgery in the same institution, especially those lacking an IAT, with vascular medicine, cardiology, interventional radiology variably involved in aspects of medical or procedural care. In a siloed model, individual disciplines may employ different treatment strategies for the same aortic segment, or perhaps overreach in discussing alternatives to their preferred therapy. ³⁰ Three years after implementing an aortic team model to discussions of distal arch and thoracoabdominal aortic pathology, McClure and colleagues found that interdisciplinary care was sustainable and feasible despite inherent logistical challenges. The authors suggested that the IAT model mitigated bias in clinical decision-making, promoted interdisciplinary “cross-pollination,” and allowed for equipoise between open and endovascular strategies even in the face of growing enthusiasm for novel endoarch and complex thoracoabdominal techniques and devices. ³⁰

Finally, crucial to shared decision-making of optimal treatment strategy is additional discussion of the risks of prolonged hypothermic circulatory arrest, cardiopulmonary bypass, and spinal cord ischemia management strategies, necessitating early involvement of cardiovascular anesthesiologists and perfusionists. Cardiovascular anesthesiologists play a pivotal role in the perioperative “continuum” between preoperative planning, intraoperative management, and postoperative transition to intensive care, making them core team members in complex aortic disease management. ³³

Barriers to Implementation

The interdisciplinary approach is not without logistical challenges. Similar obstacles are encountered in other cardiovascular interdisciplinary teams. ³⁴ Adjusting from a siloed care model to an interdisciplinary, one requires the selection of team members who share both an expertise in aortic disease and an enthusiasm for collaboration. Traditional hierarchies or dominant personalities may sabotage efforts to create an integrated, coordinated care pathway. ¹³

The management of acute aortic syndromes requires highly organized and efficient care pathways. Acute “aortic codes” have been suggested as a means to engage an IAT early. ³⁵ Members of an IAT may be paged or otherwise contacted collectively when an acute aortic emergency is identified, quickly organizing core members for a group discussion. Simultaneously, hospital resources, such as operating room space and staff, critical care beds, and transport services are secured. This requires administrative support to allocate appropriate resources locally.

By creating algorithms and protocols for acute care pathways, the interdisciplinary team members can be unburdened from many of the logistical hurdles involved in care coordination and instead focus on patient-focused treatment options. Even some patient-care decisions can be streamlined by frequent case-based discussions, morbidity and mortality conferences, and other quality care initiatives that seek to standardize and review institutional practices. By protecting time and resources for these important initiatives, hospital administration can further ensure the durable success of an IAT.

Conclusion

Although prospective data are lacking, IATs are widely accepted as a critical component to clinical excellence in complex aortic care. In acute aortic syndromes, a team of experts combining individual experience is best suited to create a unified patient evaluation and management plan that encompasses the gamut of procedural options, both open and endovascular, and optimal medical therapy. The widespread adoption of the IAT will not only foster enhanced quality in patient care, but also have downstream implications for aortic disease data collection and research, training, and innovation.