CT-based tool finds subgroups with increased risk of secondary stroke

Imaging with CT may help provide clinicians with a clearer picture of a patient’s secondary stroke risk, a group of Canadian researchers found in a study of patients with a transit ischemic attack (TIA) or a non-disabling stroke.

According to the study published online Dec. 4 in Stroke, clinicians were able to determine patient risk by reviewing CT scans and determining whether the patient had acute or chronic ischemia or microangiopathy separately or in combination. Findings were used in addition to age, blood pressure, clinical features, duration of TIA and diabetes mellitus (ABCD2) scores.

The research team followed 2,028 patients who presented to the emergency department within 24 hours of symptom onset and underwent CT scans within that same period. Based on CT findings, patients were classified in one of seven groups having solely or some combination of chronic or acute ischemia or microangiopathy. Patients were followed to determine if a subsequent stroke happened in two days or less, more than two days or up to 90 days after initial TIA.

Jason K Wasserman, MD, PhD, of the Ottawa Hospital Health Research Institute at the University of Ottawa in Ontario, Canada, and colleagues observed a 90-day stroke rate of 3.4 percent. Of these, 1.9 percent occurred beyond two days from the initial TIA, while 1.5 percent occurred within two days or fewer of the initial stroke.

Acute ischemia was an integral part of increased stroke rates. Acute ischemia alone was associated with a 10.6 percent increase in stroke by 90 days. Combined with chronic ischemia or microangiopathy, rates increased to 17.4 percent and 17.6 percent. Among patients with acute and chronic ischemia and microangiopathy, one in four had a secondary stroke within 90 days. Acute ischemia represented odds for recurrent stroke of 2.61 by 90 days, 2.7 at more than two days and 2.71 at two days or less.

Odds were highest for patients with acute and chronic ischemia and microangiopathy of recurrent stroke at 90 days and two days or less: 8.29 and 22.69, respectively.  

Patients with ischemia or microangiopathy had higher median ABCD2 scores in general. However, median scores were similar between acute ischemia and microangiopathy and acute and chronic ischemia and microangiopathy and patients whose CT scans were not associated with increased risk of stroke. With this in mind, Wasserman et al endorsed using imaging as part of ABCD2 scores to add more predictive weight to the scale by taking acute ischemia into consideration. 

"These findings should prompt physicians to be more aggressive in managing patients with TIA or non-disabling stroke who are diagnosed with acute ischemia, especially if there is additional chronic ischemia and/or microangiopathy," Wasserman said in a press release.