A Review of the Complexities of Morning Hypertension

Dr. Page is an associate professor of clinical pharmacy and physical medicine and a clinical specialist, Division of Cardiology, University of Colorado Health Sciences Center, Schools of Pharmacy and Medicine.

As with most biologic processes,blood pressure (BP) demonstratesa distinct circadianrhythm, characterized by a substantialreduction during sleep (the nocturnaldip) followed by a moderate to markedincrease around the time of awakening(the morning surge). It is not surprisingthat the onset of acute cardiovascular (CV)events (eg, myocardial infarction, suddencardiac death, and stroke) also showsa circadian pattern, with peak occurrenceduring the early morning hours.^1,2In patients with hypertension, this surgein BP (eg, above 135/85 mm Hg) duringthe first 2 hours after waking, but not inthe evening (the last 2 hours before goingto bed) has been defined as morninghypertension.³ This morning BP surge haspathological significance as it is positivelyrelated to degree of target-organ damage,such as carotid intima-media thicknessand left ventricular hypertrophy.^4-6 Themagnitude of the morning surge also is anindependent predictor of cerebrovascularand cardiac events.⁷

Nondippers Versus Extreme Dippers

Two types of morning hypertension exist.^8-10The patients who demonstrate a nocturnaldecrease in BP that is <10% of theirdaytime BP are known as nondippers. Theother type of patients are the extreme dipperswho exhibit a 20% or more decreasein nocturnal BP, compared with daytimeBP. Finally, a patient can be an inverteddipper/riser in which their BP does notdecrease or actually may increase at night.Nondippers and risers typically do notshow a surge in BP on awakening but usuallyhave sustained early morning hypertension.An excessive morning surge iscommon in extreme dippers.^8-10

What Causes Morning Hypertension?

The morning surge in BP is influenced bymany pathophysiological factors, such asactivity of the autonomic and renin-angiotensin-aldosterone systems and dietarysodium intake. Other alterations thatoccur during the early morning that canhave a significant impact on increasing CVrisk in this population include increasedheart rate, vascular tone, blood viscosity,and platelet aggregability. With the adventof ambulatory blood pressure monitoring(ABPM), this technology has improvedidentification of patients with excessivemorning surges and has facilitated assessmentof antihypertensive agents that maybe particularly effective in this subgroupof the hypertensive population.^11,12

In the Japan Morning Surge-1 study,Ishikawa and colleagues used ABPM in611 patients with morning hypertensionto determine important patient-specificcharacteristics.¹³ The analysis showedthat patients with morning hypertensionare more likely to be of older age, as wellas have a longer duration of hypertensionand antihypertensive medication use, displaya higher prevalence of left ventricularhypertrophy with an elevated B-type natriureticpeptide concentration, and exhibit alower glomerular filtration rate.

As for pharmacotherapy, choice of anagent is dependent upon the pharmacokineticsand formulation of the drug,published evidence, and timing of administration.Medications with long half-lives,such as telmisartan, amlodipine, chlorthalidone,and bisoprolol, have demonstratedefficacy in controlling early morning BP.Bedtime administration of chronotherapeuticpreparations as well as alphablockerssuch as doxazosin have alsobeen effective, particularly when used incombination with ABPM.^14-24

This communication on the importance of home blood pressure monitoring is supported by Omron Healthcare, Inc. It is intended to help pharmacists and their staff understand the importance of home blood pressure monitoring.

References

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