2017 guidelines dissected by a stroke neurologist
NEW ORLEANS -- When it comes to blood pressure (BP) targets, tailoring for certain groups is probably better than specifying a blanket "optimal" level for all stroke patients, clinicians agreed during a debate here.
Current American College of Cardiology/American Heart Association (ACC/AHA) BP guideline recommendations for acute stroke management and secondary prevention are "reasonable" but one "must be careful about lowering BP," according to stroke neurologist Philip Gorelick, MD, MPH, of Thorek Memorial Hospital in Chicago. "It's not just the BP level -- it's the variability of BP."
have been shown to predict neurological deterioration and worse functional outcomes. "Consider early stabilization of BP in an attempt to avoid variability of BP and persistently elevated BP," he told the audience during a session at the AHA's annual Hypertension meeting
Gorelick discussed the guidelines alongside Paul Whelton, MD, MSc, of Tulane University School of Medicine in New Orleans, who offered his perspective as the chair of the ACC/AHA guideline writing committee.
As in the previous version, the 2017 ACC/AHA guidelines say that acute ischemic stroke patients should be kept at BPs under 185/110 mm Hg before tissue plasminogen activator (tPA) treatment and 180/105 mm Hg in the 24 hours after drug therapy; if there is no alteplase or endovascular treatment, it may be reasonable to lower BP by 15%.
The literature suggests that BP-lowering therapies are generally safe in acute ischemic stroke but do not reduce the risk of death or major disability. And in the absence of these benefits, there's actually concern that secondary outcomes could worsen with BP-lowering medication, according to Gorelick.
It may therefore be reasonable to withhold BP-lowering medication if there is no compelling reason to reduce it, at least until the patient is medically and neurologically stable, he said.
Whelton noted that CATIS, the largest trial to date assessing acute BP lowering in acute ischemic stroke, found that immediate BP reduction made no difference in death or major disability.
But perhaps the investigators intervened too early back then: CATIS-2 is now underway with 5,000 patients getting BP-lowering intervention 24-48 hours after stroke onset, according to the guideline leader.
As for acute intracerebral hemorrhage, the guidelines say that bringing systolic BP under 140 mm Hg is harmful to patients, and Gorelick agreed: "Too precipitous and too low a target may be dangerous," he said, citing the INTERACT-2 and ATACH-2 trials showing no reduction in hematoma growth, death, or disability with intensive BP control.
He suggested modifying the AHA/American Stroke Association systolic BP target to 140-150 or 160 mm Hg in this setting.
Preventing Recurrent Stroke, Dementia
A 130 mm Hg systolic target is now recommended by the ACC/AHA for secondary stroke prevention.
Gorelick said it's reasonable to go down to less than 140 mm Hg or less than 130 mm Hg -- the latter especially after lacunar infarctions -- using diuretics, angiotensin-converting enzyme inhibitors, and other classes of BP-lowering agents.
Most trials in secondary prevention have been underpowered, suggesting trends toward fewer events with intensive BP therapy without reaching statistical significance, according to Whelton.
Recently, however, the RESPECT trial and a recent meta-analysis both showed that intensive BP treatment significantly reduced stroke recurrence over standard treatment.
Meanwhile, the rationale for lowering BP to preserve cognition also remains controversial.
For elderly patients over 80 years old and those with cognitive impairment, Gorelick advised caution, as there is concern about cerebral autoregulation when BP goes too low.
"There's a lot of observational data that patients who start developing cognitive impairment do worse when BP drops. [The question is] whether we need to boost BP to keep it high, so they can perfuse better," according to the stroke neurologist.
Whelton argued that the subgroup of SPRINT participants who were 75 years or older "seemed to do as well as anybody in the trial" on intensive BP control and as a very high-risk cohort even showed low numbers-needed-to-treat.
Concern over the BP "J-curve" has made some people nervous about going too low. However, "I would say as an observational epidemiologist, we see J-curves in everything. Take weight, cholesterol, sodium ... It's almost inevitable. When you look at a J-curve, it's usually reverse causality [driven by] sick people," Whelton said.
"It's not to say you should be cavalier about BP therapy," he clarified. "But the high-risk individuals who benefited most from the intervention are the people who we might be too cautious with."
Gorelick reported financial relationships with Bayer, Novartis, Amgen, and Vindico Medical Education.
Source Reference: Gorelick PB "Is there a best blood pressure target post-stroke for outcome improvement? Neurologist's perspective" Hypertension 2019.
Source Reference: Whelton PK, et al "Is there a best blood pressure target post-stroke for outcome improvement: ACC/AHA BP guideline perspective" Hypertension 2019.
Read the original article on Medpage Today: How Do the Controversial BP Targets Stack Up in Stroke?