In 2014, the American Heart Association/American Stroke Association (AHA/ASA) updated guidelines for secondary prevention in patients with ischemic stroke or transient ischemic attack (TIA). “These guidelines are updated every few years so that clinicians can stay up to date on the most current research on strategies to maintain a low risk of recurrent events,” explains Walter N. Kernan, MD, who chaired the AHA/ASA writing group that updated the recommendations. The document, which was published online in Stroke: Journal of the American Heart Association, was last updated in 2011.
After an initial ischemic stroke or TIA, 3% to 4% of affected patients will have a new ischemic stroke each year. “This figure is historically low because careful attention has been paid to using science-based interventions for secondary prevention,” says Dr. Kernan. “However, the scientific developments in the area of secondary prevention for stroke and TIA are accumulating rapidly. As a result, guideline updates are needed at least every few years.”
The updated guidelines include new sections on nutrition and sleep apnea (Table 1) and revisions of several other sections, including those dealing with hypertension, dyslipidemia, diabetes, carotid stenosis, and atrial fibrillation (AF). Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances. These include aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. The AHA/ASA document also has made it easier for clinicians to recognize new changes to the guidelines by including a table that details the major additions and revisions.
Using the Guidelines
“For clinicians who use the AHA/ASA guidelines, it’s critical to carefully assess the cause of a patient’s stroke or TIA before initiating secondary preventive treatments,” says Dr. Kernan. “After the cause is identified, clinicians can use the guidelines to determine which therapies are most appropriate, depending on patients’ specific characteristics. For example, some patients may have suffered a stroke related to AF. For these individuals, it’s paramount that they receive anticoagulants.” In addition, patients who have a stroke should be monitored for AF for at least 30 days after hospitalization (Table 2).
Dr. Kernan notes that hypertension is one of the most important treatable risk factors that should be addressed as a part of secondary prevention measures for stroke and TIA. “Hypertension leads the list of major risk factors for stroke recurrence,” he says. The guidelines provide clarifications regarding when to initiate or resume antihypertensive therapy in these patients. Blood pressure-lowering therapy should be started in previously untreated patients with a blood pressure level of 140/90 mm Hg or higher after the first several days following an ischemic stroke or TIA.
The guideline writing group also revised the dyslipidemia section so that it is consistent with recently updated cholesterol guidelines from the American College of Cardiology and AHA. Other revisions to the sections on carotid stenosis, AF, and prosthetic heart valves were made to be consistent with recently published guidelines from AHA and the American College of Chest Physicians.
The AHA/ASA update places greater emphasis on lifestyle factors, including diet, exercise, and weight management. “Studies are establishing the role of nutrition as a secondary prevention measure for stroke and TIA,” says Dr. Kernan. Although more data on this aspect of care are expected in the future, the guidelines currently recommend that clinicians conduct nutritional assessments and that patients be encouraged to avoid routine use of vitamin supplements and reduce their sodium intake.
More to Come
Another change appearing in the 2014 update from AHA/ASA is that there is a greater appreciation for the impact of clinically silent brain infarctions. These events can be detected on brain imaging and are associated with typical risk factors for ischemic stroke. They can increase the risk for future ischemic strokes and unrecognized neurologic signs in the absence of symptoms. The writing committee identified silent infarction as an important and emerging issue in secondary stroke prevention.
Dr. Kernan anticipates that future research will discover more strategies for managing intracranial atherosclerosis and idiopathic ischemic stroke. “With data rapidly emerging, there is hope that we can add additional evidence-based approaches to secondary prevention for these important aspects of stroke and TIA,” he says. “In the meantime, clinicians can use this as their ‘go to’ reference for identifying optimal preventive treatments for specific patients.”
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