Chapter 14: Vascular Surgery

Introduction

Vascular surgery is a constantly evolving specialty, and evidence-based care is a rapidly moving target. Treatment of vascular disease has changed dramatically over the 24 years since the North American Symptomatic Carotid Endarterectomy Trial (NASCET),¹ the earliest clinical trial referenced in this chapter, was published. Although new medications, procedures, and strategies have greatly expanded the number of treatment options available to vascular surgeons and their patients, they also create challenges in generalizing prospective trial results and applying them to individual patients.

Several studies covered in this chapter compare medical versus procedure-based management strategies for vascular disease. When interpreting study results, it is important to remember that within clinical practice these treatments are typically utilized in an additive fashion; that is, procedure-based treatments are often performed in addition to (rather than instead of) aggressive medical therapy. It can be challenging, however, to determine how advances in medical therapy should impact procedural intervention criteria when trial-based head-to-head comparisons include outdated approaches. The NASCET¹ and Asymptomatic Carotid Artery Stenosis (ACAS)² trials exemplify this phenomenon. Although both of these studies were well designed and contributed important evidence to guide management of symptomatic and asymptomatic carotid stenosis, respectively, advances in medical therapy since their publication (including more standardized approaches to cardiovascular risk reduction, routine use of statin therapy, and availability of more aggressive antiplatelet regimens) have likely narrowed the gap in outcomes between medical and procedure-based treatment. Although many practitioners using contemporary medical therapy for carotid stenosis have transitioned to more conservative utilization of procedural intervention (particularly for asymptomatic disease) based on improved medical treatment outcomes, updated evidence is not available to precisely define objective management criteria. New randomized trials comparing contemporary medical therapy alone with and without procedural intervention for carotid stenosis are currently underway, and it is foreseeable that additional trials may be warranted in the future as medical and procedural treatments continue to advance. Similar challenges exist for healthcare providers trying to use results from randomized trials comparing medical versus procedural management to guide treatment of venous thromboembolism^3,4 and symptomatic renal artery stenosis,⁵ particularly when medical options are unacceptable or have failed.

Prospective trials comparing different approaches to procedural intervention (often open surgical vs. endovascular) are another valuable source of clinical evidence. Randomized comparisons between open and endovascular treatment of carotid stenosis, abdominal aortic aneurysm (AAA), and peripheral arterial disease (PAD) are abundant in the vascular surgery literature, and we include examples of each in this chapter.^6,7,8 None of the included studies was the first randomized comparison published between the treatments under consideration, but rather the most recent contribution to a larger group of randomized studies, many of which may have different inclusion criteria, endpoints, and conclusions. Those seeking to gain a more comprehensive understanding of the issues, controversies, and limitations related to these trials should refer to the previous randomized trials referenced in the ...