麻豆传媒

NEW YORK -- The 24-hour ambulatory blood pressure monitoring (ABPM) levels measured in the SPRINT trial came out higher than careful, automated office readings on intensive treatment, whereas the standard-target arm went as expected, researchers said here.

In the intensive treatment arm targeting under 120 mm Hg systolic, the single ABPM measurement at around 27 months came out at near the same time.

In the arm aiming for the standard 140 mm Hg, the numbers went the opposite direction at 134.0 mm Hg on ABPM and 135.5 mm Hg in-office.

Overall, , of the University of Minnesota in Minneapolis, and colleagues concluded at the late-breaking session here at the American Society of Hypertension meeting that there was "poor agreement between clinic blood pressure and ambulatory blood pressure" and chalked it up to a persistent or increased masked hypertension effect with intensive treatment.

"We never see that," commented , of Virginia Commonwealth University in Richmond. "These results fly in the face of our notions."

Ambulatory measurements have been shown to be stronger predictors of cardiovascular and renal blood pressure than standard clinic blood pressures, which are typically higher and show bigger effects of treatment than ambulatory measures.

"For example, in the Symplicity HTN-2 trial, renal sympathetic denervation resulted in a 32-mm Hg decrease in clinic systolic blood pressure but only an 11-mm Hg decrease in 24-hour ambulatory systolic blood pressure," Drawz noted.

But in SPRINT, daytime ambulatory systolic pressure was 7 mmHg higher than clinic-measured values in the intensive group as compared with only 3 mmHg higher in the standard group, Drawz pointed out.

"The measurement technology may have been partly an explanation for it," Sica told 麻豆传媒, although cautioning about the limitations of relying too much on a single ambulatory measure at 27 months with no baseline.

The SPRINT ABPM ancillary study included 500 participants in each of the two treatment arms who received ABPM every 30 minutes over a 24-hour period within 3 weeks of the 27-month study visit at 15 sites. Shift and night workers were excluded, as were people with end-stage renal disease, and those with large arms or the possibility of lymphedema due to prior mastectomy.

The clinic blood pressure measurement wasn't usual care, but rather an average of three readings with the Omron automated measurement system after the patient had been seated quietly for 5 minutes not talking, interacting with people, or filling out questionnaires.

, of New York's University at Buffalo, agreed that technology was possibly at play.

"The automated system sort of deconvolutes the white coat hypertension concept," he said. "It's much less sensitive to all those perturbations and looks a lot more like ambulatory blood pressure numbers. I do trust it more. No other trial has done it like they did it."

But it's also possible that the difference is not just due to the technology but also the treatment, Sica pointed out. "It may be that bringing blood pressure as low as they did took away some of the benefit of the ambulatory monitoring. Usually ambulatory is better than just a clinic visit blood pressure, but it's never really been studied below 120."

Either way, the difference in automated office readings versus ABPM compared with what would be expected with usual non-automated office readings does make SPRINT more difficult to interpret, Izzo and Sica agreed.

"The difference now is much less between the two treatment groups than heretofore had been the case," Sica said. The difference between the two treatment arms was 15.97 mm Hg by in-clinic measures versus 11.14 mm Hg by ambulatory measures at 27 months.

But it's not clear whether a similar degree of separation achieved in practice as measured by non-automated office readings would have the same, more, or less impact on clinical outcomes as SPRINT. It's even possible that SPRINT maxed out on benefit, such that a bigger separation in ambulatory pressures wouldn't have done better, Sica suggested.

SPRINT trialist , of the University of Alabama at Birmingham cautioned against a direct translation of the intensive treatment target to usual clinical practice.

Automated in-office measures gives lower values than having a person apply the cuff in the exam room, she told 麻豆传媒.

"So if you tried to get the usual office blood pressure, which is done in a sort of disorganized fashion with the patient running around, as the measure to lower the blood pressure to 120, you could get into trouble. Because of that delta, you'd really be lowering it to a range we don't know much about. Less than 115 we don't think is necessarily safe," she said. "We're hoping that practices will get tuned to using an automated oscillometric device with that rest period."

Ambulatory monitoring has been recommended by the U.S. Preventive Services Task Force for confirming diagnosis of hypertension, but as Izzo noted, "people don't like doing it. It is a pain."

If the SPRINT approach with automated readings in the office "is a half way compromise, it's a pretty good compromise," he noted. "It's way better than what we have been doing."

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