Cardiac stents

Policy Context

A stent is a stainless mesh tube that can be collapsed and attached to the end of a balloon catheter. When the catheter tip is floated to an area of stenosis, the balloon is inflated to expand the stent. The balloon is then deflated and detached from the stent. The stent remains in the artery permanently to act as a physical scaffold to help keep the artery open. The first aim of this assessment is to systematically review, critically appraise and analyze research evidence comparing the safety and efficacy of percutaneous coronary intervention with stenting (PCI) with medical therapy in patients with stable CAD. If there is evidence that PCI with stenting is more effective than medical therapy alone in preventing death or myocardial infarction (MI) and/or improving patient quality of life, the second aim is to update the 2009 HTA on coronary artery stenting by systematically reviewing, critically appraising and analyzing new research evidence comparing the safety and efficacy of percutaneous coronary intervention with newer generation FDA-approved drug eluting stents (DES) with bare metal stent (BMS).

Status: Decision completed

Cardiac stents were first reviewed in 2009.
  • In 2015, the HCA director selected cardiac stents for rereview based on newly available evidence published since the 2009 assessment that could change the original coverage determination.

  • A rereview of cardiac stents was conducted in 2016.

Primary criteria ranking

  • Safety = High
  • Efficacy = High
  • Cost = Medium
Documents (all assessments)

Assessment (2016)

Assessment (2009)

Assessment timeline (2016)

  • Draft key questions published: July 10, 2015
  • Public comment period: July 10 to 24, 2015
  • Final key questions published: August 31, 2015
  • Draft report published: October 20, 2015
  • Public comment period: October 20 to November 18, 2015
  • Final report published: December 14, 2015
  • HTCC public meeting: January 15, 2016

Background

Coronary artery disease (CAD), also referred to as coronary heart disease (CHD) or ischemic heart disease (IHD), is the single leading cause of death for both men and women in the U.S. and is the most common form of cardiovascular disease; thus the economic and public health burden of CAD is considerable. Atherosclerosis is the most common underlying cause of CAD. It is a disease process in which plaque (comprised of lipids, inflammatory cells, smooth muscle cells, and connective tissue) builds up on artery walls. Partial or complete blockage of coronary arteries can occur with plaque formation and may prevent the portions of the heart muscle from receiving blood, oxygen, and vital nutrients. Atherosclerosis can cause blockage by two mechanisms: 1) progressive narrowing of the artery due to the plaque narrowing the vessel lumen, and 2) thrombotic occlusion of the artery, which occurs when the hard surface of a plaque tears or breaks off, exposing the inner fatty pro-thrombotic, plateletattracting components to the site, resulting in enlargement of the blockage. Coronary atherosclerotic plaque disruption and associated intraluminal platelet-fibrin thrombus formation are responsible for the acute coronary syndromes of acute MI, unstable angina (UA), and probably for sudden death.

Chest pain (angina) is the most common symptom of obstructive CAD and is the presenting symptom in at least 50% of patients with CAD. Because of the poor correlation between symptoms and CAD, clinicians must rely on a careful history and other modalities to detect and confirm a suspicion of CAD. Classic angina is characterized by retrosternal chest discomfort, often described as a crushing pressure. The discomfort may radiate to the jaw, neck, back, shoulder or arm. It can be accompanied with dyspnea, diaphoresis, nausea and syncope. If the discomfort presents (1) in a predictable pattern, (2) is brought on by physical or mental stress, and (3) subsides with rest or angina medication such as nitroglycerin, it is called stable angina, which is consistent with stable CAD. One can have stable CAD but not have angina with optimal medical therapy. Angina that occurs with less exertion, causes greater discomfort, or takes longer than 20 minutes to subside may be an ominous warning of critical ischemia and has been termed unstable angina. Unstable angina is classified as part of acute coronary syndrome (ACS).

In general, persons with angina already have CAD lesions with at least 75% obstruction and are at increased risk of MI, heart failure and sudden death due to plaque destabilization and thrombosis. Evidence-based recommendations for medical management are now advised for all persons with CAD. Optimal medical therapy, or the newer term, guideline directed medical therapy, includes lifestyle modifications (physical activity, smoking cessations, weight management and dietary changes) as well as treatment of secondary conditions within current guidelines (diabetes and hypertension), risk modification with antiplatelet drugs and management of lipid levels and treatment of angina symptoms if present. For patients with stable CAD with low risk for coronary events, guideline directed medical therapy may be the only treatment. For patients with stable CAD determined to be at high risk for coronary events, treatment may involve both medical therapy and revascularization therapy, with the goal of reducing mortality risk and/or improving symptoms. For patients considered at high risk of coronary events, invasive coronary angiography for further risk stratification and assessment of appropriateness for revascularization may be the next logical steps in addition to medical therapy.

Overall, consideration of revascularization is based on the clinical presentation (acute coronary syndrome or stable angina), the severity of the angina (based on Canadian Cardiovascular Society Classification), the extent of ischemia on noninvasive testing, and the presence or absence of other prognostic factors including congestive heart failure, depressed left ventricular function, and diabetes, the extent of medical therapy, and the extent of anatomic disease. Revascularization methods include coronary artery bypass graft surgery (CABG) and percutaneous coronary interventions (PCI).