Dallas, TX - On the strength of data showing that as many as 40% of patients with a large-vessel stroke or transient ischemic attack (TIA) have subclinical heart disease, a new joint statement from the American Heart Association and the American Stroke Association urges risk-factor assessment for all such patients and noninvasive testing for those considered at high risk.

"There is plenty of material on how to manage acute stroke patients, and there are guidelines on what to do for a patient with heart disease, but there was nothing that addressed the need to look for silent coronary ischemia in the ischemic stroke patient and the options," lead author Dr Robert J Adams (Medical College of Georgia, Augusta) told heartwire .

The new document is an attempt to define the prevalence of asymptomatic cardiac disease among these patients, assess short-, intermediate-, and long-term coronary risk associated with ischemic stroke, set out options for risk assessment, and suggest management options for when subclinical disease is found. "So the first part was written more by the Stroke Council and the second part by the cardiologists," Adams said. "We were hoping that this would provide some guidance, but clearly there is a need for more research to really refine any approach."

Higher long-term risks

For this document, members of the Stroke Council and the Council on Clinical Cardiology for the AHA/ASA reviewed current data from a variety of sources. Review of studies on the prevalence of CHD in patients with TIA or stroke, for example, suggested that 20% to 40% of stroke patients have abnormal tests for silent cardiac ischemia.

Looking at the time course of this risk, they found that short-term risk was relatively low, with between 2% and 5% of patients having a fatal coronary event in the first 90 days after their stroke. Intermediate-term (30 days to two years) risk of MI or cardiovascular death ranged from 1.5% to 5%, less than the risk of recurrent stroke. However, in the long term, studies suggest that 24% to 45% of deaths among patients with ischemic stroke were related to vascular disease other than stroke, and the risk for a cardiac event surpasses that of recurrent stroke.

Perhaps not surprisingly, large-vessel stroke was most closely related to cardiac risk, Adams said, since coronary disease affects the large vessels of the heart and shares the same risk factors. In addition, those with carotid disease and patients with a cardioembolic cause of stroke appear to have a higher likelihood of accompanying CHD, and those with small-vessel strokes a lower likelihood.

The document provides several recommendations based on the data reviewed, including the following:

       • All patients with ischemic stroke or TIA should undergo a comprehensive assessment of          cardiovascular risk, and risk-factor reduction is recommended in all cases, regardless of whether          additional noninvasive testing is undertaken.

       • Noninvasive testing should be undertaken when patients have a high cardiovascular risk profile          along with symptoms of brain ischemia; those with a high CHD risk-factor score based on the          Framingham risk score (ie, a 10-year CHD risk 20%) should also be considered for          noninvasive testing.

      • Testing for CHD can be performed with a variety of methods described in practice guidelines, but           because the risk for short-term cardiac mortality and morbidity is low, it need  not be carried out           in the acute stroke setting  "unless there is concern that the patient may not be available at a later           time for this evaluation."

       • Diagnostic testing to determine the mechanism underlying a stroke, particularly the presence of          carotid disease, is recommended since this will provide information not only on cardiac risk but          on secondary-stroke-prevention strategies.

Treatment unresolved

What to do about asymptomatic heart disease once it is discovered among those with cerebral ischemia is still an unresolved question, the document notes, beyond the obvious benefits of risk-factor reduction. What seems clear is that patients with silent ischemia and noninvasive manifestations of ischemia such as a very abnormal ECG have a similar poor prognosis to those with symptomatic ischemia and similar evidence of ischemia on noninvasive testing, the authors write. Studies also suggest that medical treatment and revascularization may favorably affect prognosis in those with silent as well as symptomatic ischemia.

"Given the fact that the prognosis for these patients is worse than that for comparable healthy persons, it is reasonable to consider some form of therapy beyond risk-factor reduction, pending further definitive research," the researchers note. "However, it is important to state that definitive data are lacking for therapeutic outcomes in patients with concomitant coronary and cerebrovascular arterial disease," they add, and their recommendations are based on "opinion and not on hard clinical-trial outcomes."

"Clearly, more randomized, controlled studies are needed in this area."

Sources

Adams RJ, Chimowitz MI, Alpert JS, et al. Coronary risk evaluation in patients with transient ischemic attack and ischemic stroke: a scientific statement for healthcare professionals from the Stroke Council and the Council on Clinical Cardiology of the American Heart Association/American Stroke Association. Circulation 2003 Sep 9; 108(10):1278-90. Available at: http://circ.ahajournals.org/