Stroke: CAS may lessen need for antihypertensive drugs
Arterial hypotension is a complication of CAS, and studies have shown varying degrees of hypotension after CEA. Aysun Altinbas, MD, of the Utrecht Stroke Center in Rudolf Magnus Institute of Neuroscience at University Medical Center in Utrecht, the Netherlands, and colleagues designed their study to compare changes in BP after CAS and CEA as well as to compare the use of antihypertensive drugs between baseline and 12 months of follow-up. Their goal was to better understand the effects of the two treatments on BP.
They used the ICSS, an ongoing international randomized controlled trial designed to compare the risks, benefits and costs of CAS and CEA in patients with carotid stenosis of greater than 50 percent. The study protocol included baseline measures and follow-up at 30 days, six months, 12 months and each subsequent year after treatment. Among the measures were BP and records on the use of antihypertensive medications, antithrombotic medications and statins.
The primary outcome was changes in systolic BP and diastolic BP. The secondary outcome was use of antihypertensive medications during follow-up. They assigned patients to either a CAS group (766 patients) or a CEA group (819 patients).
Altinbas and colleagues found at baseline no difference in systolic BP and diastolic BP between the two groups, and no difference in the percentage of patients receiving antihypertensive medications. Patient characteristics were similar, with the exception that fewer patients in the CAS group had a history of cardiac failure at randomization.
Both CAS and CEA were associated with a decrease in BP early after treatment, but the decrease was greater in the CAS group. After one month, there was no difference in BP between the groups, nor was there a difference at one-year follow-up. But the percentage of patients in the CAS group who used antihypertensive medications was lower than that of the CEA group at the 30-day, six-month and 12-month follow-up periods.
The researchers characterized overall BP control in the study as “unsatisfactory,” noting that the majority of patients had systolic BP above target levels set in guidelines. “In ICSS, medical care during follow-up was at the discretion of the treating physician, and at one year, this is most likely to have been the patient’s general practitioner,” they wrote. They pointed out that stringent BP control may further reduce the long-term risk of stroke in study participants.
The study excluded patients whose records failed to include BP readings, which may have caused a selection bias, they acknowledged. Excluded patients were older, which could have led to an underestimation of BP changes. The records did not describe the type or dosage of antihypertensive medication, another shortcoming, they wrote.
“It appears plausible that because of the larger early BP reduction after CAS than after CEA, antihypertensive medication was stopped and not resumed more frequently after CAS than after CEA,” they concluded. “The absence of a difference in BP between CAS and CEA during follow-up after discharge despite lower use of antihypertensive medication suggests that CAS may have a long-term hypotensive effect compared with CEA.”