Vascular surgery

Medical science has advanced significantly since 1507, when Leonardo da Vinci drew this diagram of the internal organs and vascular systems of a woman.

The specialty continues to be based on operative arterial and venous surgery but since the early 1990s has evolved greatly. There is now considerable emphasis on minimally invasive alternatives to surgery. The field was originally pioneered by interventional radiologists, chiefly Dr. Charles Dotter, who invented angioplasty. Of note, Dr. Thomas Fogarty invented the balloon catheter which enabled angioplasty. Further development of the field has occurred via joint efforts between interventional radiology, vascular surgery, and interventional cardiology. This area of vascular surgery is called Endovascular Surgery or Interventional Vascular Radiology, a term that some in the specialty append to their primary qualification as Vascular Surgeon. Endovascular and endovenous procedures (e.g., EVAR) can now form the bulk of a vascular surgeon's practice.

The treatment of the aorta, the body's largest artery, dates back to Greek surgeon Antyllus, who first performed surgeries for various aneurysms in the second century AD. Modern treatment of aortic diseases stems from development and advancements from Michael DeBakey and Denton Cooley. In 1955, DeBakey and Cooley performed the first replacement of a thoracic aneurysm with a homograft. In 1958, they began using the Dacron graft, resulting in a revolution for surgeons in the repair of aortic aneurysms. He also was first to perform cardiopulmonary bypass to repair the ascending aorta, using antegrade perfusion of the brachiocephalic artery.

Dr. Edward "Ted" Dietrich, one of Dr. DeBakey's associates, went on to pioneer many of the minimally invasive techniques that later became hallmarks of endovascular surgery.[2] Dietrich later founded the Arizona Heart Hospital in 1998 and served as its medical director from 1998 to 2010. In 2000, Diethrich performed the first endovascular aneurysm repair (EVAR) for ruptured abdominal aortic aneurysm. Dietrich trained several future leaders in the field of endovascular surgery at the Arizona Heart Hospital including Venkatesh Ramaiah, MD[3] who served as medical director of the institution following Dietrich's death in 2017.[4]

The development of endovascular surgery has been accompanied by a gradual separation of vascular surgery from its origin in general surgery. Most vascular surgeons would now confine their practice to vascular surgery and, similarly, general surgeons would not be trained or practise the larger vascular surgery operations or most endovascular procedures. More recently, professional vascular surgery societies and their training program have formally separated vascular surgery into a separate specialty with its own training program, meetings and accreditation. Notable societies are Society for Vascular Surgery (SVS), USA; Australia and New Zealand Society of Vascular Surgeons (ANZSVS). Local societies also exist (e.g., New South Wales Vascular and Melbourne Vascular Surgical Association (MVSA)). Larger societies of surgery actively separate and encourage specialty surgical societies under their umbrella (e.g., Royal Australasian College of Surgeons (RACS)).

Arterial and venous disease treatment by angiography, stenting, and non-operative varicose vein treatment sclerotherapy, endovenous laser treatment are rapidly replacing major surgery in many first world countries. These newer procedures provide reasonable outcomes that are comparable to surgery with the advantage of short hospital stay (day or overnight for most cases) with lower morbidity and mortality rates. Historically performed by interventional radiologists, vascular surgeons have become increasingly proficient with endovascular methods.[5] The durability of endovascular arterial procedures is generally good, especially when viewed in the context of their common clinical usage i.e. arterial disease occurring in elderly patients and usually associated with concurrent significant patient comorbidities especially ischemic heart disease. The cost savings from shorter hospital stays and less morbidity are considerable but are somewhat balanced by the high cost of imaging equipment, construction and staffing of dedicated procedural suites, and of the implant devices themselves. The benefits for younger patients and in venous disease are less persuasive but there are strong trends towards nonoperative treatment options driven by patient preference, health insurance company costs, trial demonstrating comparable efficacy at least in the medium term.

A recent trend in the United States is the stand-alone day angiography facility associated with a private vascular surgery clinic, thus allowing treatment of most arterial endovascular cases conveniently and possibly with lesser overall community cost. Similar non-hospital treatment facilities for non-operative vein treatment have existed for some years and are now widespread in many countries.

NHS England conducted a review of all 70 vascular surgery sites across England in 2018 as part of its Getting It Right First Time programme. The review specified that vascular hubs should perform at least 60 abdominal aortic aneurysm procedures and 40 carotid endarterectomies a year. 12 trusts missed both targets and many more missed one of them. A programme of concentrating vascular surgery in fewer centres is proceeding.[6]

Vascular surgery encompasses surgery of the aorta, carotid arteries, and lower extremities, including the iliac, femoral, vascular trauma and tibial arteries. Vascular surgery also involves surgery of veins, for conditions such as May–Thurner syndrome and for varicose veins. In some regions, vascular surgery also includes dialysis access surgery and transplant surgery.

An abdominal aortic aneurysm (AAA) refers to aneurysmal dilation of the aorta confined to the abdominal cavity. Most commonly, aneurysms are asymptomatic and located in the infrarenal position. Often, they are discovered incidentally or on screening exams in patients with risk factors such as a history of smoking. Patients with aneurysms which have a diameter less than 5 cm are at <1% rupture risk per year. When the aneurysm meets size criteria it can be treated with aortic replacement or EVAR.

Thoracic aneurysms are contained in the chest. Aneurysms of the descending aorta can often be treated with thoracic endovascular aortic repair or TEVAR. Treating aneurysms which involve the ascending aorta are generally within the scope of cardiac surgeons, but upcoming endovascular technology may allow for a more minimally invasive approach in some patients.

Thoroacoabdominal aneurysms are those which span the chest and abdominal cavities. The Crawford Classification was developed and describes five types of thoracoabdominal aneurysms.

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  Abdominal aortic aneurysms can be classified as infrarenal, juxtarenal, pararenal or suprarenal as depicted in the illustration.
• 
  The Crawford Classification for thoracoabdominal aortic aneurysms is pictured above.

Visceral artery aneurysms include those isolated to the renal artery, splenic artery, celiac artery, and hepatic artery. Of these, data shows that splenic artery aneurysms are the most common.[9]

Indications for repair differ slightly between arteries. For instance, current guidelines recommend repair of renal and splenic artery aneurysms greater than 3 cm, and those of any size in women of childbearing age; whereas celiac and hepatic artery aneurysms are indicated for repair when their size is greater than 2 cm. This is in contrast to superior mesenteric artery aneurysms which should be repaired regardless of size when they are discovered.[10]

A popliteal artery aneurysm is an arterial aneurysm localized in the popliteal artery which courses behind the knee. Unlike aneurysms located in the abdomen, popliteal artery aneurysm rarely present with rupture but rather with symptoms of acute limb ischemia due to embolization of thrombus. Thus, when a patient presents with an asymptomatic popliteal aneurysm that is greater than 2 cm in diameter a vascular surgeon are able to offer vascular bypass or endovascular exclusion depending on several factors.[11]

The symptoms of chronic mesenteric ischemia can be classified as abdominal angina[15] which is abdominal pain which occurs a fixed period of time after eating. Due to this, patient's may avoid eating, resulting in unintended weight loss. The first surgical treatment is thought to be performed by R.S. Shaw and described in the New England Journal of Medicine in 1958. The procedure Shaw described is referred to as mesenteric endarterectomy.[16] Since then, many advances in treatment have been made in minimally invasive, endovascular techniques including angioplasty and stenting.

Acute mesenteric ischemia (AMI) results from the sudden occlusion of the superior mesenteric artery.

Chronic venous insufficiency is the abnormal pooling of blood in the lower extremity venous system which can lead to reticular veins, varicose veins, chronic edema and inflammation among other things. Population data suggests that chronic venous insufficiency affects up to 40% of females and 17% of males.[19] When chronic insufficiency leads to pain, swelling and skin changes it is referred to as chronic venous disease. Chronic venous insufficiency (CVI) is distinguished from post-thrombotic syndrome (PTS) in that CVI is primarily an issue of valvular incompetence of the superficial or deep veins whereas PTS may occur as a long-term complication of deep venous thrombosis.[20]

The vascular surgeon has several modalities to treat lower extremity venous disease which including medical, interventional and surgical procedures. For instance, venous ulceration may be treated with Unna's boots, superficial venous reflux with radiofrequency, laser ablation or vein stripping if indicated. When indicated, insufficiency in the deep veins may be treated with reconstruction of the venous valves with internal or external valvuloplasty.[21]

A medical illustration of lower extremity varicose veins.

Lower extremity varicose veins is the condition in which the superficial veins become tortuous(snakelike) and dilated (enlarged) to greater than 3mm in the upright position.[22] Incompetent or faulty valves are often present in these veins when investigated with duplex ultrasonography. Vascular treatments can include compression stockings, venous ablation or vein stripping, depending on specific patient presentation, severity of disease, among other things.

Nonthrombotic iliac vein lesions (NIVL) include May-Thurner Syndrome (MTS) whereby there is compression of the left iliac venous outflow usually by the right iliac artery leading to left leg discomfort, pain, swelling and varicose veins. NIVL encompasses compression of the iliac veins on either the right or left side.[23] Vascular surgeons may offer different treatment modalities depending on the patient presentation. Minimally invasive diagnostic and therapeutic options might include intravascular ultrasound, venography and iliac vein stenting whereas surgical management may be offered in refractory cases.[24] Surgical management strategies involve reconstruction or bypass of the affected segment such as cross-pubic venous bypass, also known as the Palma procedure.[25][26]

Deep venous thrombosis (DVT) is the formation of thrombus in a deep vein. DVT is more likely to occur in the lower extremity than the upper extremity or jugular vein. When a DVT involves the pelvic and lower extremity veins it can sometimes be classified as an iliofemoral DVT. Some evidence to suggests that performing an intervention in these cases may be beneficial whereas other evidence does not.[27] Overall, the data shows that there may be a reduction in the incidence in post-thrombotic syndrome in patients who undergo certain procedures for iliofemoral DVT but it is not without risks.[28] A vascular surgeon may offer venogram, endovascular suction or mechanical thrombectomy and in some cases pharmacomechanical thrombectomy. Some lower extremity DVT can be severe enough to cause a condition called phlegmasia cerulea dolens or phlegmasia alba dolens and can be limb-threatening events. When phlegmasia is present, intervention is often warranted and may include venous thrombectomy.

Post-thrombotic syndrome (PTS) is a medical condition that sometimes occurs as a long-term complication of DVT and is characterized by long term edema and skin changes following DVT. Presenting symptoms may include itchiness, pain, cramps and paresthesia. It is estimated that between 20% and 50% of patients will experience some degree of PTS.[29] A treatment strategy for PTS may involve the use of compression stockings.