Many ‘Minor’ Strokes Can Be Serious or Even Fatal

• Neurology • Oct 07, 05

Patients with mild or improving ischemic stroke sometimes aren’t treated with tissue-plasminogen activator (tPA) because their symptoms appear to be minor.

This may be a big mistake, cautioned researchers here and in Los Angeles.

Among 128 patients who showed up at the hospital within three hours of stroke onset, 41% didn’t get tPA because they appeared to be “too good to treat,” reported investigators from the Massachusetts General Hospital (MGH) and Beth Israel Deaconess Medical Center in Boston, and the University of California at Los Angeles.

But of this group that didn’t get thrombolytic therapy, 27% didn’t make it out of the hospital on the night they arrived, either because they died, or because their symptoms worsened enough to require admission, according to study results are reported in the online version and November print issue of Stroke: Journal of the American Heart Association.

“Our primary finding was that about 30% of those patients judged ‘too good to treat’ either died or were discharged to a rehabilitation facility,” said Eric Smith, M.D., a neurologist at MGH. “Unfortunately we were not able to find any features that could predict which of the untreated patients would have problems.”

Their data suggest that a re-evaluation of stroke severity criteria for intravenous tPA administration may be warranted, Dr. Smith and colleagues wrote.

Although studies have shown that about 29% to 43% of patients who present within three hours of onset ischemic stroke don’t receive tPA because their symptoms are mild or improving, one study has shown that “32% of such patients died, calling into question the decision not to treat,” the investigators wrote.

They took a retrospective look at data on 128 patients who presented to the MGH emergency department within three hours of onset of symptoms of ischemic stroke. All patients in the study underwent head CT scans, followed by either CT angiography, magnetic resonance angiography, or catheter angiography.

The investigators defined vascular occlusion as a partial or complete arterial-filling defect attributed to thrombus. They used modified Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria to assign stroke pathophysiology, and grouped patients with cardioembolism and cryptogenic embolism into a category which they called proximal-source embolism.

Rapid early improvement was defined as at least a four-point improvement in the National Institutes of Health Stroke Scale (NIHSS) from time of initial evaluation to the time of the tPA decision. Neurological worsening was defined as at least a two-point worsening in the NIHSS score from the time of the tPA decision to the time of hospital discharge.

The primary study outcome was the proportion of patients unable to be discharged home from the emergency department.

A total of 41 of the 128 patients (34%) were not given tPA because of mild or improving stroke. Of these patients, 11 of 41 (27%) died or were not discharged home, six because of neurological worsening, and five because of persistent “mild” neurological deficit. The persistent deficits included cognitive impairment, gait impairment from hemiparesis, and ataxia.

Two such patients who were initially deemed too good to treat had right internal carotid artery stenosis with embolism to the right middle cerebral artery. Each of these patients had rapid early improvement but then worsened with development of large middle cerebral artery territory infarctions. These patients died.

The remaining nine patients in the too-good-to-treat group were discharged to rehabilitation facilities.

“No single variable at presentation was associated with death or lack of home discharge,” the investigators wrote. Ten of the of the 41 patients (24%) who did not get tPA had a greater than four-point improvement in NIHSS score before the tPA decision was made, but these patients were more likely to have subsequent neurological worsening (relative risk, 4.1, 95% CI, 1.1 to 15.4; P=0.05).

Rapid early improvement “appears to confer a risk of subsequent neurological worsening, consistent with data from clinical trials showing that patients with substantial early recovery or clinical transient ischemic attack were at greater risk of subsequent neurological deterioration,” the authors wrote. “We note that three of five rapid improvement patients with visualized vascular occlusion had imaging performed after clinical improvement, suggesting that adequacy of collateral flow may be a critical factor in the clinical outcome in these patients.”

In other words, the rapid improvement appears to occur as the brain takes temporary advantage of the extra supply of blood caused by the occlusion.

Still, despite the link between rapid improvement and neurological worsening, six of the 10 patients who experienced speedy clinical improvement were able to be discharged home, the authors noted.

“Right now we can only recommend that physicians be a little more cautious in deciding against tPA treatment,” Dr. Smith said. “We can suggest that more attention be paid to patients’ ability to walk – something that often is not evaluated – since gait disturbance was a reason why several could not go home. But we really need to find ways to predict who will do poorly without tPA, and for that we’ll need larger trials involving several institutions.”

Source:
Smith EE et al. Poor Outcomes in Patients Who Do Not Receive Intravenous Tissue Plasminogen Activator Because of Mild or Improving Ischemic Stroke. DOI: 10.1161/01.STR.0000185798.78817.f3