The curse of wisdom—making sense of the ever-changing blood pressure
targets
Part 2
BP targets according
to comorbidities and CV risk calculators- too much of a good thing?
Given the scope and thoroughness of
trials in the field of hypertension, why has the post-SPRINT landscape been
littered with such controversy?
1)
A uniform protocol
for measuring blood pressure remains unresolved. Many physicians have
become disenfranchising citing their frustration with not only having to keep
up with the guidelines but now qualifying BP readings according to how they
were ascertained (i.e. via the auscultatory or oscillometric method). However,
the clinician should not assume that the methodology for measuring BP has been
an overlooked technicality within the specialty. Whether it be the debate as to
the width of the BP cuff or the validation
protocols for ensuring BP
machine accuracy (the AAMI validation protocol is 125 pages), researchers
continue to dedicate their lives to answering these questions and have created
journals (e.g. Blood Pressure Monitoring)
to disseminate their findings
2)
The rapid
succession of discordant guideline statements. In
2004, JNC 7 recommended a universal
BP goal of ≤ 140/90 mm Hg. Because JNC 8 was not published for another decade
(2014), the JNC 7 guidelines were widely circulated and institutionalized. As
such, when JNC 8 recommended
a BP of ≤ 150/90 mmHg for those older than 60, many felt a law of nature had
been violated (In defense of the JNC 8 authors, the panel was charged with
generating recommendations based exclusively on “definitive evidence.” It was
therefore limited with respect to the trials and publications it could cite). Just
12 months later, SPRINT
furthered this sense of tumult. It not
only showed the benefit of treating to previously unheard-of levels (120/80 mm
Hg) but stood in sharp contrast to the BP targets found in the JNC 8 guidelines
published 1 year earlier. Just 2 years after SPRINT, the ACC/AHA
guidelines appeared (2017), incorporating treatment to ≤130/80 mm Hg in
high risk populations, an affirmation that lower targets were to be immediately
implemented.
3)
The demise of a
universal blood pressure target. Further serving to agitate matters, the
determination of BP goals now requires the prescriber to quantify a patient’s
cardiovascular risk level (yet an additional calculation) and consider which
medical condition one should tailor BP therapy to (the optimal BP for secondary
prevention of stroke is different from that for preventing kidney disease
progression). This latter, treat-by-comorbid approach quickly loses its
intuitive appeal when patients suffer from multiple comorbids, each with a
distinct BP target (i.e. a kidney disease patient with a prior stroke).
Given the frustration and confusion generated, should we
resign ourselves to the “more questions than answers” doctrine emblematic of
modern medicine? Should we wax nostalgic for days gone by? For our
patient’s sake and the survival of our specialty, we should not. These
variations in treatment goals represent the ongoing maturation of the field of
hypertension and the source of perpetually declining CV event rates. Just as Part
1 of this piece highlighted the early challenges of accepting that
hypertension was a pathologic process, the challenge of our times is to
relinquish some of our clinical autonomy in order to integrate (complex)
treatment algorithms. The oncology community has been at the vanguard of
leveraging these developments. With distinct chemotherapeutic regimens based on
the hormonal and genetic profiles of phenotypically similar cancers, they have
come to appreciate that this “complexity” is the foundation of precision medicine.
Guest Post by
Hillel Sternlicht, MD
Author, Concepts in Hypertension Newsletter
Author, Concepts in Hypertension Newsletter
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