Hypertension is the most potent and prevalent risk factor for CVD not only in the U.S, but globally. Although we know that lipids are extremely important for MIs and vascular disease, uncontrolled hypertension is perhaps the most prevalent risk factor for HF, strokes and end-stage renal disease, often comorbid with diabetes.
The problem is in usual clinical care, hypertension is measured in a haphazard manner. There have been data which have accumulated over the last several years that out-of-office BP and specifically ambulatory BP monitoring will give a more accurate and expert diagnosis for hypertension and the various forms of hypertension than the usual clinic BP.
For clinical practice, we should recognize the lack of accurate BP in the routine medical visit. Many patients have not met the appropriate means of checking BP including resting, arm supported, back supported, feet on the floor, no eating, drinking or smoking.
That being said, even if the BP is measured appropriately in the clinical setting, out-of-office BP may be even more determinant of hypertension burden. That would take into account white-coat hypertension, where patients may have elevated BP in the clinic setting but normal BP outside the clinic setting; masked hypertension, where patients may have BPs which are apparently controlled in the clinic setting, but outside the clinical setting may have increased burden from undetected elevated BP; and nocturnal hypertension, where BP may be persistently elevated during the nighttime hours, at which point there’s an increased risk for CVD.
In the European guidelines, ambulatory BP measurement has been suggested for all new patients for the diagnosis of hypertension in an effort to detect those persons who have white-coat hypertension or masked hypertension, and to give a better assessment of the appropriate diagnosis.
In the U.S. population, ambulatory BP monitoring has not been universally approved. Without payment, the use of this technology has been underutilized in usual clinical practice.
CMS previously paid for its use only for white-coat hypertension, but is now stating that this tool may be available for patients for improved diagnosis and also for masked hypertension. Because 24-hour BP monitoring is recommended, it will be an opportunity for clinicians to get an assessment of nocturnal hypertension, which was previously not measured in the clinical setting since patients were no longer being seen.
The CMS recommendations unfortunately don’t finalize payment. One of the recommendations is to take out-of-office BP prior to initiating ambulatory BP monitoring. There still is clinicians’ time and effort to diagnose BP out of the office with or without ambulatory BP monitoring and the time and effort to appropriately interpret out-of-office BP that is often not reimbursed.
The other consideration is that, especially in most patients who are at very high risk, there may be indeed more impetus in treating patients vs. waiting until they manifest target organ damage. Therefore, especially for African American patients, older patients, patients with chronic kidney disease and those with diabetes, the appropriate use of clinical BP in the office setting may even supersede the need for ambulatory BP monitoring per se.
There are some data that suggest that using an automated office BP approach called automated office BP monitoring or measurement (AOBP), in which the person has their BP measured in as many as six times with one discarded and the others averaged, can actually reproduce to a large extent mean 24-hour daytime BP. The technique of AOBP often has been utilized as a surrogate for daytime ambulatory BP monitoring. This can be done in usual clinical practice if an appropriate digital machine is available.
The presence of absence of a condition in the room when the BP is measured remains controversial. Nevertheless, multiple BPs averaged during the clinical setting is more important than a random BP taken in the midst of a very busy practice day where patients are often rushed into the room, sat on an exam table with an arm dangling while speaking to a medical assistant and getting measurement of a BP which may actually be an invalid representation of their true level of BP.
Keith C. Ferdinand, MD, FACC, FAHA, FNLA, FASH
Cardiology Today Editorial Board Member
Tulane University School of Medicine
Disclosures: Ferdinand reports no relevant financial disclosures.