Aortovascular medicine: what is it?

Introduction

The term aortovascular, invariably followed by the suffix ‘disease’, ‘medicine’ or ‘surgery’, has recently appeared in the medical literature^1,2 and in the designations and descriptions of individuals, centres or specialist symposia, and is now even featured in Gray’s Surgical Anatomy. ³ Pathology of the aorta has traditionally been considered the realm of cardiac and vascular surgeons, with the choice of specialty largely depending on whether the disease process occurred in the chest or the abdomen. Surgeons have generally performed aortic reconstructions as part of a general cardiac and/or vascular practice, which may have included coronary and valve surgery, peripheral arterial and venous surgery, endovascular intervention for occlusive peripheral artery disease and other cardiovascular procedures. More recently, the work of surgeons has been complemented, in many health economies, by physicians with an interest in vascular disease. Indeed, vascular medicine is a sub specialty of internal medicine, with established international societies, such as the Society of Vascular Medicine (USA), the American Society of Angiology and the European Society of Vascular Medicine already providing governance structures. This begs the questions: why is a new term (or, indeed, a new subspecialty) needed? What makes the aorta different from other blood vessels? This Commentary explores the concept of aortovascular disease and the practice of aortovascular medicine and surgery.

Aortovascular disease

Arterial occlusion due to atherosclerosis is by far the most common life- and organ-threatening vascular pathology treated by cardiovascular physicians and surgeons in the developed world. This process, which is largely related to ageing and environmental factors such as smoking, diabetes or hypertension, can affect the distal aorta, but is only one of its many, varied pathologies, many of which are rarely, if ever, encountered in the peripheral circulation. While some of these diseases are localised to a short segment of the vessel, others, such as congenital aortopathies, dissection or degenerative thoraco-abdominal aneurysms, can be extensive, sometimes simultaneously involving both the thoracic and abdominal portions as well as its branches. This variety often results in unique diagnostic and therapeutic dilemmas, which invariably require input by multiple specialists. The complexity and peculiarity of aortic disease, which, unlike atherosclerosis, often has a strong genetic basis ⁴ is a significant driver of subspecialisation among surgeons and physicians and underlies the concept of aortovascular disease.

Aortovascular surgery

Surgery on the aorta is always challenging, and often a formidable undertaking both for the surgical team and the patient. In recent decades, we have witnessed a significant evolution of the interventional approach to aortic pathology. In cardiac surgery, there has been a progressive refinement of organ protection techniques to allow the safe performance of proximal aortic surgery, which, by its own nature, requires interruption of the natural blood flow through the main aortic branches. ³ In vascular surgery, the advent of endovascular techniques and their subsequent evolution created a minimally invasive alternative for patients with extensive aortic pathology, to the point that some pioneers already foresee the possibility of replacing the whole aorta by endovascular means. ⁵ Although cardiac and vascular surgeons pursued innovation somewhat independently, there is an increasing awareness that many patients with aortic disease require input from both, and that the separation between the two specialties, when it comes to aortic disease, is artificial, largely dependent on the skills acquired by individual surgeons during their specialty training. The term aortovascular surgery thus emerged as collaboration between cardiac and vascular surgeons has become commonplace, particularly in the treatment of complex thoracic and thoraco-abdominal pathology, driven by an increased understanding, among surgeons, of the possibilities afforded by the ‘other’ specialty. This understanding, which has resulted in a degree of skill mix between the two specialties, has also created a number of therapeutic options for patients with complex aortic disease. Indeed, hybrid surgical-endovascular (and cardiac-vascular) procedures are now part of the standard armamentarium of many aortic units ⁶ (Figure 1). Additionally, in most hospitals, other specialists such as interventional radiologists and interventional cardiologists also contribute to endovascular surgery, further expanding the specialty base necessary to deliver modern aortic intervention. There is indeed an increasing data-driven acceptance that adequate delivery of aortic surgery requires centralisation in dedicated centres, ⁷ a fact that has been acknowledged by healthcare commissioners in the United Kingdom. ⁸ In our centre, where the necessary skills are not found in any single individual, the case of every potential candidate for complex aortic surgery is discussed by a multidisciplinary team capable of offering open, endovascular and hybrid intervention as well as conservative therapy, consisting, as a bare minimum (as it is sometimes the case in the emergency setting), of a vascular and a cardiac surgeon. Aortovascular surgery is thus a truly multidisciplinary enterprise, and a particularly relevant concept to health economies in which, as in the United Kingdom, accreditations in cardiac and vascular surgery remain separate.

Figure 1.

Example of hybrid surgical/endovascular aortic procedure. The patient had a complicated aneurysm of the distal aortic arch. She underwent de-branching of the supra-aortic vessels from the proximal ascending aorta via median sternotomy and ante-grade stenting of the arch and proximal descending thoracic aorta via a side-arm of the tri-furcated Dacron graft (arrow). The procedure was performed without cardiopulmonary bypass as a less invasive alternative to a total arch replacement, which would have required deep hypothermic circulatory arrest and ante-grade cerebral perfusion. (a) Operative view. (b) Post operative 3D reconstruction of CT angiographic images. The patient has consented to anonymous publication of intraoperative photography.

Aortovascular medicine

Traditionally, much of the medical care of patients with aortic disease has been delivered by surgeons. This aspect of our practice has become particularly complicated due to advances in various areas, such as advanced aortic diagnostic imaging, discovery of the genomic basis of aortic disease, improved perioperative risk management and care, understanding of inflammatory aortopathies and knowledge of the natural history of the primary disease process. Due to the variety of aortic disease, the wide age range of our patients and the multitude of surgical/endovascular interventions that we provide, it is difficult for surgeons to rely on rigid management and follow-up protocols. It is instead clear that an individualised approach is needed in the majority of cases. In practice, it has become increasingly difficult for surgeons to manage the medical aspect of patient care while focusing, at the same time, on the highly technical demands of aortic intervention. In our centre, this complexity has been addressed by migrating medical care from surgeons to a multi disciplinary team, which, in our case, include surgeons, adult and ‘congenital’ cardiologists, clinical geneticists, imaging and interventional radiologists, anaesthetists and a physician with an interest in vasculitides. To coordinate this care, we recently appointed an ‘aortovascular physician’, whose role will include the development of clinical pathways to manage patients with specific aortic diseases, and who will interface with individual specialists (surgeons, cardiologists, anaesthetists, geneticists, radiologists and others) on a case-by-case basis. We anticipate that once the role is established, the aortovascular physician will be the point of reference for the management of all patients with aortic disease, thus freeing the surgeon (and, where appropriate, interventional radiologists and cardiologists) to concentrate on technical aspects of intervention and perioperative care. We foresee the medical care afforded to our patients to be based on the principles of personalised medicine, and fully expect the approach to change during individual patients’ lifetimes, in line with new knowledge and healthcare progress – all coordinated by our aortovascular medicine hub.

Conclusions

Aortovascular medicine describes the emerging multi-disciplinary care needed by a heterogeneous group of patients, whose management requires skills and expertise that go beyond those of the traditional cardiovascular surgeon or vascular physician. We introduced the concepts of aortovascular surgeon, as an individual proficient in complex aortic intervention and of aortovascular physician, as a new specialist coordinating multi-faceted, personalised patient management from cradle to grave. We foresee a constant evolution of these roles in time, but we are convinced that they will gradually separate from the figures of present specialists, such as the vascular physician and the cardiovascular surgeon.