Prevention of Second Strokes: Aiming at Better Arrows and Targets
Pub Date: Thursday, Oct. 21, 2010
Author: Junya Aoki, MD
Furie KL, Kasner SE, Adams RJ, et al; on behalf of the American Heart Association Stroke Council, Council on Cardiovascular and Stroke Nursing, Council on Clinical Cardiology, and Interdisciplinary Council on Quality of Care and Outcomes Research. Guidelines for the prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2010: published online before print October 21, 2010, 10.1161/STR.0b013e3181f7d043.
The American Heart Association and American Stroke Association published a comprehensive revision of the Guidelines for the Prevention of Stroke in Patients with Stroke and Transient Ischemic Attack (TIA) 2 years after the last update.[1,2] The revision is a helpful resource for clinicians to find cogent summaries of recommendations and references for the scientific bases for the recommendations. To highlight, the recent advances included in the document include 1) inclusion of recent trial results of glycemic control among persons with type 2 diabetes mellitus to improve vascular outcomes, 2) a new chapter on the metabolic syndrome, 3) endovascular management in persons with large artery atherosclerosis, including carotid disease, and 4) atrial fibrillation (AF).
The guidelines reflect new knowledge of limitations in the approach to "aggressive risk factor treatment." Although lipid recommendations have lower low-density lipoprotein targets in some subgroups, diabetes recommendations are less aggressive. Among persons with type 2 diabetes mellitus, two large scale trials, ACCORD and ADVANCE, which tested the benefit of aggressive glycemic control, failed to show benefits in preventing stroke or vascular events as a whole. In the ACCORD substudy of blood pressure treatment, the blood pressure lowering target of <120 mm Hg reduced stroke but increased serious adverse events without overall benefit in vascular outcome. The mention of glucose control of "near-normoglycemic levels" to prevent macrovascular complications in prior guidelines is gone. Now, the document recommends "use of existing guidelines for glycemic control and blood pressure targets" as Class I, Level of Evidence B.
Metabolic syndrome is added as a modifiable behavior, while the obesity section has become slim. The definition of the metabolic syndrome was performed with the criteria proposed by National Cholesterol Education Program. The utility of screening for metabolic syndrome after stroke or TIA is still not clear. However, if it's diagnosed, patients should receive counseling for lifestyle changes and treatments for components that are also stroke risk factors, especially high blood pressure and high cholesterol (Class I, Level of Evidence A).
Since the last 2006 guidelines, endovascular procedures have gained important scientific grounds. Carotid angioplasty and stenting (CAS) is presented as an alternative to carotid endarterectomy (CEA) for symptomatic patients at average or low risk of complications (Class I, Level of Evidence B). These recommendations might prove controversial or practice-altering. The beginning of the chapter is more neutral in emphasizing scientific uncertainty: "Clinical equipoise exists with respect to its [CAS's] comparison with CEA." The European trials of EVA-3S, SPACE are discussed, but not the more recent International Carotid Stenting Study. All pointed to higher periprocedural stroke rates after CAS compared to CEA. Yet, the long-term outcome of CREST, the largest and a well-run North American trial, is taken to show in that there is no difference between the two procedures. The periprocedural stroke rate was consistently higher in CAS compared with CEA across multiple studies, including CREST. The short-term and long-term data of CREST is presented in a separate table. Nonetheless, the guidelines come to a conclusion of "reasonable alternative" for average-risk patients. The recommendation that follows immediately should be noted as well: "CAS in the above setting is reasonable when performed by operators with established periprocedural morbidity and mortality rates of 4% to 6%." Adoption of CAS in clinical practice should occur in the hands of experienced operators while tracking of clinical outcomes and complications. Endovascular approaches to the patients with intracranial atherosclerosis are also described as a new recommendation. However, we should keep in mind that this approach is still under investigation; and thus, the evidence level is low. Emphasized now is the optimal medical management; this guideline explicitly recommends (at Class I, Level of Evidence B) the role of the optimal medical therapy, including antiplatelet therapy, statin therapy, and risk factor modifications in patients with large-artery disease.
Concerning AF management, results of ACTIVE-A and -W are incorporated but do not essentially change the recommendation for adjusted warfarin. The efficacy of dabigatran over warfarin in stroke prevention was shown in the RE-LY study and is discussed, but its lack of Food and Drug Administration approval prevented its incorporation into the recommendation. Availability of dabigatran to patients is awaited, and it may dramatically change stroke prevention in AF. The PROTECT AF study suggests that a new endovascular strategy for patients with AF might reduce stroke risk, but such an approach is far from being recommended. The temporary interruption of oral anticoagulation with a low-molecular-weight heparin bridge is referred to as reasonable therapy for AF patients with high risk of stroke (Class IIa, Level of Evidence C). Although the scientific strength is not high, the presence of this recommendation may be a reminder of stroke risk during antithrombotic therapy cessation.
For practicing clinicians, we wish there were discussions of the following topics, if not explicit recommendations. We wish there were a discussion on the risk-benefit balance of antiplatelet therapy in the background of warfarin anticoagulation among those with AF with coronary heart disease. Although shown to be higher risk for hemorrhagic complications than warfarin alone, aspirin and warfarin combination is not uncommon to see in practice. Aortic arch atheroma is not mentioned in this document. Its importance in stroke risk recurrence has become evident, but there is little data on management.
In conclusion, these comprehensive and timely, evidence-based recommendations can improve the management of patients with stroke or TIA and prevent stroke recurrence.
- Furie KL, Kasner SE, Adams RJ, et al. Guidelines for the prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2010.
- Adams RJ, Albers G, Alberts MJ, et al. Update to the AHA/ASA recommendations for the prevention of stroke in patients with stroke and transient ischemic attack. Stroke 2008;39(5):1647-52.
-- The opinions expressed in this commentary are not necessarily those of the editors or of the American Heart Association