Finding cause of stroke an important aspect of care

Stroke is one of the most feared occurrences in modern medicine, particularly among modern cardiovascular diseases.

In discussing risks and benefits of procedures in patients with CVD, stroke is of greater complication concern than either death or MI. This is, in part, related to the vivid mental description that patients and physicians alike have of patients with severe disability following stroke.

Statistics indicate that in the United States, there are 700,000 new or recurrent strokes per year, and that stroke ranks third among all causes of death. Just as importantly, or even more importantly for patients, stroke is the leading cause of serious disability. From a societal standpoint, the direct and indirect cost of stroke for 2006 was approximately $58 billion. The ripple effect of stroke is therefore vast, affecting everyone from the individual to the family unit to society as a whole.

David R. Holmes, Jr.

There is considerable information on the demographics of stroke, which includes the age dependence of stroke. As patients of all gender and races grow older, the incidence of stroke increases significantly; of interest is the fact that silent cerebral infarctions are not uncommon, particularly in older patients.

The prevalence of age-adjusted incidence of stroke after an initial decline from 1960 to 1980 has remained relatively stable. Given the relationship of increasing age and the increasing incidence of atrial fibrillation and subsequent stroke, the incidence of stroke may also increase. Survival after stroke has been found to be significantly impaired, particularly after a cardioembolic stroke.

Metrics of care

The time dependency of stroke has received increasing attention. In this regard, there are parallels between acute MI and stroke. Metrics of care between the two have some similarities with emphasis on the timeliness of care and/or reperfusion. The situation for stroke is different in that stroke can be caused not only by thrombotic occlusion, but also by intracerebral hemorrhage. Distinguishing between the two etiologies is of obvious, crucial importance and requires prompt access to central nervous system imaging.

Yet another parallel to acute infarction includes utilization of lytic therapy, both systemic and increasingly local, as a treatment for thrombotic stroke, as well as the use of anti-platelet therapy and interventional devices such as balloon dilation, stent placement and distal protection devices.

After the stroke has been treated, intense efforts need to be undertaken to identify the substrate that was involved. In patients with a thromboembolic event, the source should be identified if at all possible. In some patients, it will be the result of severe carotid arterial disease; in others it will be the result of friable atheroma in the ascending aorta or the arch.

Other considerations include a cardioembolic source. Data would suggest that cardioembolic strokes are larger and result in substantially more morbidity and mortality. There has been considerable interest in the association between a patent foramen ovale and paradoxical embolus as a cause of stroke, as well as in the relationship between AF and stroke. The importance of the search for the specific cause cannot be over-emphasized enough.

In patients with structural heart disease, such as a patent foramen ovale, the defect can now be closed percutaneously. For patients with AF, in whom the source of the thrombus is typically the left atrial appendage, there are devices that can be used to occlude that structure, thereby preventing subsequent embolization, as well as eliminating the need for chronic administration of warfarin. In patients with a hemorrhagic stroke, intense efforts should be made to also identify the mechanism. Whether that relates to chronic anticoagulant therapy, untreated hypertension or a vascular anomaly is of great importance, as it will guide therapy.

A number of physician groups play an increasingly important role in stroke management. These include neurologists, neurosurgeons, interventional cardiologists and neuroradiologists. It is anticipated that there will be continued development of multidisciplinary stroke centers for optimizing patient care.

David R. Holmes Jr., MD, is a Professor of Medicine at the Mayo Clinic, Rochester, Minn., and a Member of the Interventional Cardiology section of the Today in Cardiology Editorial Board.