Perspectives in Vascular Surgery and Endovascular Therapy

Carotid artery stenting (CAS) has emerged as a useful and potentially less invasive alternative to carotid endarterectomy (CEA) for the treatment of extracranial carotid stenoses. In this regard, it has been suggested that specific patient subgroups who may benefit from CAS including those with significant medical comorbidities, recurrent stenosis, anatomically inaccessible lesions, and a hostile neck. However, the purpose of this report is to evaluate whether or not CAS should replace CEA in the treatment of symptomatic and asymptomatic disease in better risk patients, also. This report contains results from recently published randomized clinical trials.

Stroke is the third leading cause of death in the United States. Carotid artery stenosis represents one of the most common etiologies of stroke. The current treatment modalities available for the treatment of carotid artery stenosis are carotid endarterectomy (CEA) and carotid artery stenting (CAS). Several clinical trials comparing CEA with medical management showed superiority of the surgical arm; however, the applicability of these results to the general population is limited by the fact that the patients and surgeons enrolled in these trials were carefully selected, and the optimal medical therapy used does not meet the current treatment standards. Carotid artery stenting has emerged as a treatment alternative to CEA, as shown in randomized trials comparing the 2 treatment modalities. Recent data from large-volume CAS registries indicate that percutaneous treatment of carotid artery stenosis compares favorably to CEA. Furthermore, the CAS trial designs make these results more applicable to the community standards. These data suggest that CAS will become the treatment of choice in patients with carotid artery stenosis.

Endovascular techniques have gradually become the preferred treatment modality for occlusive disease of the supra-aortic trunks (SAT). Stenotic lesions are particularly amenable to catheter-based therapy. Standard cervical bypasses or intrathoracic reconstruction is now generally reserved for cases of extensive, multivessel involvement or after failure of previous endovascular procedures.

Angiographic assessment of aortic arch anatomy and equipment and technical choices for arch branch catheterization constitute the foundations. The left subclavian artery is most frequently diseased; interventional options revolve around antegrade and retrograde techniques. Preservation of the left vertebral artery—and at times of the internal mammary—is an important issue. Treatment of lesions in the proximal common carotid arteries tends to be straightforward when dealing with focal stenoses. Embolic protection should be used whenever feasible and reasonable. The innominate is often the most challenging SAT vessel because of its large diameter and short length, as well as the fact that it bifurcates into the right subclavian and common carotid arteries. Right subclavian artery intervention tends to be more difficult than its left-side counterpart, which is related to fluoroscopic visualization and the tendency for stenoses to develop in the very short segment between its origin and the take-off of the right vertebral artery.

Supra-aortic trunk intervention has become more commonplace at present, but it is frequently difficult and carries significant potential for failure and mishap. These risks can be minimized through a complete understanding of the full spectrum of technical and catheter choices that are available to the interventionist.

Statins belong to a class of drugs known to inhibit 3-hydroxy 3-methylglutaryl coenzyme A (HMG CoA) reductase, and block hepatic cholesterol synthesis. Statins have been found to be highly effective in primary and secondary stroke prevention among medically managed patients with cardiovascular disease, and it appears that this benefit is largely owing to the non-cholesterol-lowering, so called pleiotropic, effects of statins.

Over the past decade, agents such as beta-blockers, aspirin, or other antiplatelet medications have proven to reduce the incidence of adverse postoperative outcomes among vascular surgical patients and have rightfully assumed a place in our overall therapeutic armamentarium. There is growing evidence that statins may be especially effective in reducing cardiovascular morbidity and improving outcome following major vascular surgery. A recent study from Johns Hopkins Hospital demonstrated a threefold reduction in the rate of perioperative stroke (P < .05) and fivefold reduction of perioperative mortality (P < .05) among 1566 patients undergoing carotid endarterectomy (CEA). This benefit was confirmed in a series of 3360 CEAs performed at multiple hospitals throughout western Canada. Statin use was independently associated with a 75% reduction (OR: 0.25; 95%CI: 0.07-0.90) in the odds of death and a 45% reduction (OR: 0.55; 95% CI: 0.32-0.95) in the odds of ischemic stroke or death among patients with symptomatic carotid disease.

A number of the pleiotropic effects of statin medications may be responsible for these clinical observations. Further work is necessary to better elucidate these mechanisms, as well as to determine the optimal agents, dosing, and timing of drug administration among patients undergoing carotid interventions. Nevertheless, in light of these data a strong case can be made to start patients on statin medications prior to CEA if time permits.

Thromboembolic complications from atherosclerotic disease of the carotid bifurcation are a common etiology of ischemic stroke, which has a significant morbidity and mortality. Carotid artery angioplasty and stenting (CAS) has been proposed as an alternative therapy for patients requiring treatment of carotid artery stenosis as opposed to the “gold standard” surgical intervention, carotid endarterectomy (CEA). Intense debate regarding these 2 therapeutic approaches has centered on their respective safety profiles. To date, despite multiple studies, no convincing evidence demonstrates the superiority or even equality of CAS to the proven safety, efficacy, and durability of CEA. This chapter reviews in detail the available evidence for CAS and CEA and provides a rationale that, given the available data, CEA remains the preferred therapy for the majority of patients who require treatment of carotid artery stenosis.

Celiac artery syndrome exists, although it remains controversial, and in some patients a firm diagnosis cannot be established. Duplex scanning or computed tomographic, magnetic resonance, or contrast aortography will confirm intermittent or permanent compression of the celiac artery by the crus of the diaphragm, the median arcuate ligament, or fibrous ganglionic tissue. Preoperative ganglion block and exercise gastric tonometry are useful diagnostic tools to predict better outcome after treatment. In patients with well-defined syndrome of chronic mesenteric and gastric ischemia or with exercise-induced pain, good results can be expected with division of the median arcuate ligament with open celiac artery reconstruction. Patients with atypical pain or history of psychiatric disorders only occasionally benefit from surgical repair. The role of primary stenting of celiac artery compression is still not well defined, and current data do not support the use of balloon-expandable stents. Laparoscopic division of the median arcuate ligament followed by celiac artery stenting is an effective, minimally invasive technique to manage selected patients with celiac artery compression syndrome.

Renal artery angioplasty and stenting is commonly performed for the treatment of hypertension and ischemic nephropathy. An increasing number of procedures are being undertaken for “renal preservation” despite an associated risk of renal function decline related to the embolization of atheromatous debris liberated during the procedure. Although smaller, more flexible guidewires and stents have been developed to decrease the amount of debris created, interest in the off-label use of embolic protection devices has increased. We review the available embolic protection devices and currently available data regarding their use in renal artery interventions. Although not designed for use in the renal artery, there are at least theoretical reasons to believe that embolic protection during renal artery angioplasty may improve outcomes.

When ruptured abdominal aortic aneurysms (AAAs) are not treated, they cause death. In addition, ruptured abdominal aortic aneurysms (RAAAs) have high mortality (35%-70%) and morbidity rates when treated by standard open surgical methods. These high perioperative mortality and morbidity rates have not been substantially reduced despite the introduction of many improvements in open operative technique or perioperative care. Endovascular approaches to treat AAAs introduced in the early 1990s provided an opportunity to substantially alter treatment outcomes when rupture occurred. This article details how these endovascular approaches, which include endovascular stented grafts, can be applied to the treatment of RAAAs, and what advantages these new catheter-based approaches to treatment offer.

The endovascular recanalization of long infrainguinal arterial occlusions has made significant progress in the past decade. The technique of subintimal angioplasty has opened the door to the treatment of lesions uncross-able using standard transluminal approaches. With the advent of new wires and catheters designed to traverse long lesions, and reentry devices used to facilitate the subintimal approach, percutaneous treatment has made substantial inroads into territory previously dominated by surgical bypass. Advances in stent technology have improved deliverability and patency in these difficult applications. Percutaneously delivered covered endografts into the femoropopliteal segment may allow better patency by performing like endoluminal prosthetic bypasses. In this article, we review the latest technology available to treat occlusions of the femoropopliteal arterial segment.

Longevity of lower-extremity revascularization procedures has typically been limited because of restenosis of grafts, as well as stents and other percutaneous techniques. The ability to prevent or ameliorate neointimal hyperplasia and improve durability of lower-extremity arterial reconstruction is the focus of significant scientific and clinical research. The transcription factor decoy edifoligide was investigated as a potential inhibitor of neointimal hyperplasia, but the results of the pivotal clinical trial did not demonstrate significant improvement in graft reintervention, although secondary patency was improved. Similar to the coronary circulation, drug-eluting stents are a potential tool for prevention of restenosis after percutaneous arterial reconstruction. The SIROCCO study did not demonstrate improvement in superficial femoral artery stent patency with sirolimus-eluting stents. Studies are underway that are investigating paclitaxel-eluting stents for use in the superficial femoral artery. Other potential mediators of restenosis include absorbable drug-eluting stents and antibody-coated stents designed to promote endothelialization of the stent or graft surface. In addition, absorbable wraps eluting paclitaxel can be used at arterial and arteriovenous anastomoses to prevent restenosis. Clinical trials investigating these novel technologies are underway.

Infrainguinal occlusive disease is a complex problem necessitating the cooperation of both medical and surgical therapies to aid limb salvage and alleviate symptoms. Endovascular therapies are varied, with no treatment clearly outweighing the other in terms of efficacy and durability. Angioplasty for focal stenosis has gained ground as the treatment of choice when indicated. There has also been a rapid evolution in stent technology, from early stainless steel wall stents to today's drug eluting nitinol stents. In this article, we examine the literature on these new technologies and treatment options and make recommendations based on the best data available.

Radiofrequency ablation of the great saphenous vein has become increasingly popular for its decreased morbidity and greater patient satisfaction as compared with conventional saphenous vein stripping. Because of the relative simplicity and safety of this procedure and fueled by changes in reimbursement, endovenous radiofrequency ablation is now most often performed as an office-based procedure. This sets the stage for developing new technology that can achieve better results in a shorter time without compromise to patient safety and satisfaction. The balance between patient satisfaction and increased productivity is tenuous, and the former should never be sacrificed for the latter. The recipe for such a seemingly formidable task begins the moment the patient sets foot in the waiting area. Recognizing the steps that cause patient anxiety and strategically turning them into comfort zones takes a concerted effort between the surgeon and office staff. Here, we demonstrate how simple changes can transform an office-based endovenous practice into one in which patient and physician alike are maximally satisfied.

Over the past decade, there has been a renewed interest in venous disease by the vascular community. This is predominantly because of new advances in endovenous treatment and practice economics. To broaden the services provided, vascular surgeons want to learn about sclerotherapy. Most commonly used for cosmetic concerns, it also plays a role in the broad spectrum of venous pathology treatment. The supplies and equipment needed with an overview of available sclerosants are discussed. Basic techniques and compression therapy are reviewed. This article will serve as a basic primer for successfully adding sclerotherapy to your practice.

The management of cosmetic vein problems requires a very different approach than that for the majority of most other vascular disorders that occur in a vascular surgery practice. This article focuses on the business aspects of a cosmetic vein practice, with particular attention to the uniqueness of these issues. Managing patient expectations is critical to the success of a cosmetic vein practice. Maneuvering within the insurance can be difficult and frustrating for both the patient and the practice. Practices should use cost accounting principles to evaluate the success of their vein work. Vein surgery—especially if performed within the office—can undergo an accurate break-even analysis to determine its profitability.

Currently, the anticoagulants available are limited to warfarin, heparin compounds, and direct thrombin inhibitors. Warfarin, the most commonly used outpatient anticoagulant, has significant shortcomings. There are numerous drug/drug and drug/food interactions, and there is difficulty in dosing for one-third of patients. Numerous new anticoagulants are undergoing testing. The meta-pentasaccharides use the core molecule of heparin and replace one or more of the sulphated groups. They are administered by subcutaneous injection, but they require only once per week dosing. Numerous studies have shown equivalents or superiority to warfarin in treatment for thromboembolic events.

Direct thrombin inhibitors block thrombin (IIa) and are used mostly for heparin-induced thrombosis or during coronary interventions. However, there is an orally administered direct thrombin inhibitor, Dabigatran, which is undergoing phase III testing. It can be given without regard to weight, age, or gender with minimal drug interactions. This drug has been proven to be equivalent to low molecular weight heparin (LMWH) in deep venous thrombosis (DVT) prophylaxis and showed no excess bleeding.

Another promising group of anticoagulants with numerous investigations underway are the direct X inhibitors. Most are excreted renally as opposed to hepatic clearance with intravenous or oral dosing. Numerous phase II studies have shown them to have equivalent or superior prophylaxis for DVT when compared with LMWH. Oral IXa inhibitors and an oral thrombin cofactor inhibitor are also under development. It is clear that in the near future, anticoagulants will be available that offer significant advantages when compared to those currently in use.

Background: Angiotensin-converting enzyme (ACE) inhibitors prevent the expansion and rupture of aortic aneurysms in animals. We investigated the association between ACE inhibitors and rupture in patients with abdominal aortic aneurysms.

Methods: We did a population-based case-control study of linked administrative databases in Ontario, Canada. The sample included consecutive patients older than 65 (n = 15 326) admitted to hospital with a primary diagnosis of ruptured or intact abdominal aortic aneurysm between April 1, 1992, and April 1, 2002.

Findings: Patients who received ACE inhibitors before admission were significantly less likely to present with ruptured aneurysm (odds ratio [OR] 0.82, 95% CI 0.74—0.90) than those who did not receive ACE inhibitors. Adjustment for demographic characteristics, risk factors for rupture, comorbidities, contraindications to ACE inhibitors, measures of health-care use, and aneurysm screening yielded similar results (0.83, 0.73—0.95). Consistent findings were noted in subgroups at high risk of rupture, including patients older than 75 years and those with a history of hypertension. Conversely, such protective associations were not observed for β blockers (1.02, 0.89—1.17), calcium channel blockers (1.01, 0.89—1.14), α blockers (1.15, 0.86—1.54), angiotensin receptor blockers (1.24, 0.71—2.18), or thiazide diuretics (0.91, 0.78—1.07).

Interpretation: ACE inhibitors are associated with a reduced risk of ruptured abdominal aortic aneurysm, unlike other antihypertensive agents. Randomised trials of ACE inhibitors for prevention of aortic rupture might be warranted.