Need to Lower High Blood Pressure After Stroke
Should Not Rule Out Use of Clot-Busting Drug
HOUSTON – (Sept. 8, 2008) – Patients who require aggressive therapy to lower their blood pressure following a stroke do not appear to be at a higher risk for bleeding or other adverse outcomes after receiving anti-clotting therapy, according to a study done by researchers at The University of Texas Medical School at Houston.
Sean Savitz, M.D.
The research findings, which are published today in the September issue of Archives of Neurology, could translate to a treatment option for as many as 10 percent of patients with acute ischemic stroke who previously would have been ineligible to receive tissue plasminogen activator (tPA) because of high blood pressure.
Sean Savitz, M.D., co-director of the Stroke Program at The University of Texas Medical School at Houston and an attending neurologist at Memorial Hermann - Texas Medical Center, said high blood pressure can increase the risk of bleeding if tPA – the only proven therapy for acute ischemic stroke – is used to dissolve the stroke-causing clot in the brain. Because of that risk, patients with high blood pressure who otherwise would have qualified to receive tPA were left with no stroke treatment options, said Savitz, one of the study’s authors.
The researchers set out to answer whether aggressively lowering the patient’s blood pressure and then administering tPA could be done without increasing the risk of bleeding or causing other adverse events.
Sheryl Martin-Schild, M.D., Ph.D., then of the University of Texas Health Science Center at Houston and now of Tulane University Health Sciences Center, New Orleans, and colleagues reviewed the medical records of 178 patients with acute ischemic stroke who received intravenous tPA within three hours at Memorial Hermann - TMC. Of these, 50 required treatment for lowering blood pressure before beginning tPA therapy. This included 24 (48 percent) who received the medication nicardipine, either alone or in combination with the drug labetalol.
“We observed several important differences between patients who required blood pressure–lowering treatment and those who did not,” the authors wrote. “They had more severe strokes and their blood glucose concentration was higher, predicting they would have a worse outcome if all other factors were equal. As expected, they more frequently had a history of hypertension.”
After controlling for these factors–including age, baseline stroke severity and blood glucose levels–there were no differences between patients who received antihypertensive treatments and those who didn’t in adverse events, poor outcomes or stroke severity scores at discharge.
“Overall, the results of the present study provide the first experimental support for the revised American Heart Association guidelines allowing tPA therapy in patients requiring aggressive blood pressure management and also provides support for the use of nicardipine in patients with acute ischemic stroke who are eligible for thrombolytic therapy,” the authors concluded. “Aggressive control of severely elevated blood pressure is feasible and should not automatically exclude otherwise eligible patients with acute ischemic stroke from receiving thrombolytic therapy.”
This study was supported by a training grant from the National Institutes of Health to the UT Medical School at Houston Stroke Program.