Early Morning Blood Pressure Surge

The Role of Circadian Rhythms in Stroke: A Narrative Review

Stroke, a debilitating condition often leading to long-term disability, poses a substantial global concern and formidable challenge. The increasing incidence of stroke has drawn the attention of medical researchers and neurologists worldwide. Circadian rhythms have emerged as pivotal factors influencing stroke's onset, pathogenesis, treatment, and outcomes. To gain deeper insights into stroke, it is imperative to explore the intricate connection between circadian rhythms and stroke, spanning from molecular mechanisms to pathophysiological processes. Despite existing studies linking circadian rhythm to stroke onset, there remains a paucity of comprehensive reviews exploring its role in pathogenesis, treatment, and prognosis. This review undertakes a narrative analysis of studies investigating the relationship between circadian variation and stroke onset. It delves into the roles of various physiological factors, including blood pressure, coagulation profiles, blood cells, catecholamines, cortisol, and the timing of antihypertensive medication, which contribute to variations in circadian-related stroke risk. At a molecular level, the review elucidates the involvement of melatonin, circadian genes, and glial cells in the pathophysiology. Furthermore, it provides insights into the diverse factors influencing stroke treatment and outcomes within the context of circadian variation. The review underscores the importance of considering circadian rhythms when determining the timing of stroke interventions, emphasizing the necessity for personalized stroke management strategies that incorporate circadian rhythms. It offers valuable insights into potential molecular targets and highlights areas that require further exploration to enhance our understanding of the underlying pathophysiology. In comparison to the published literature, this manuscript distinguishes itself through its coverage of circadian rhythms' impact on stroke across the entire clinical spectrum. It presents a unique synthesis of epidemiological, clinical, molecular, and cellular evidence, underscoring their collective significance.

TRIPLE ANTIHYPERTENSIVE THERAPY: FOCUS ON EFFICACY AND PROGNOSIS

In the article, with regard to current clinical recommendations, the place of combined antihypertensive therapy, especially triple drugs regimens, is considered in the treatment of patients with arterial hypertension. Special focus is given to the body of evidence for the efficacy of valsartan and amlodipine, as the reference drug of angiotensin II receptor blockers and calcium channel blockers, respectively. Not only their high antihypertensive properties are demonstrated, but also a favorable effect on target-organ protection and prognosis is described. In particular, the possibilities of valsartan in reducing the severity of left ventricular hypertrophy and microalbuminuria are described, and its unique properties in the class of sartans that allow the use of this drug in patients with ischemic heart disease and chronic heart failure are emphasized. Data on the antiatherosclerotic effects of amlodipine and its proven ability to reduce cardiovascular risk are presented. Current data are presented about their use in a fixed-dose combination with hydrochlorothiazide, including real clinical practice settings. The evidence base of high clinical efficacy, safety and metabolic neutrality of the triple combination of antihypertensive drugs valsartan, amlodipine and hydrochorothiazide is presented. The issues of increasing adherence of patients to treatment when prescribing fixed-dose combinations are considered. An algorithm for the selection of antihypertensive drugs in the form of monotherapy and combination therapy of two or three drugs depending on the clinical situation (the presence of certain target-organs damages and associated clinical conditions, primarily ischemic heart disease, atherosclerosis of carotid arteries and chronic heart failure) and the severity of the additional risk of cardiovascular complications.

Dispositional self-control: relationships with aerobic capacity and morning surge in blood pressure

The psychological, behavioral and psychosocial implications of self-control are well established, but relatively little is known about its implications for physical health. This study examined the association between self-control and two important indicators of cardiovascular risk: morning blood pressure surge (MBPS) and maximum oxygen consumption (VO_2max). Undergraduate students (N = 78) completed a measure of dispositional self-control (Brief Self-Control Scale), participated in a 24-h ambulatory assessment of heart rate (HR) and blood pressure (BP), and completed the YMCA Cycle Ergometer Submaximal Test. Regression analyzes yielded a significant positive relationship between self-control and VO_2max. Results also indicated a significant negative association between self-control and MBPS, independent of average 24-h blood pressure and VO_2max scores. These findings expand our understanding of the relationship between dispositional self-control and MBPS. Study limitations and directions for future research are discussed.

Circadian Variation of Stroke Onset: A Hospital-Based Study

Aims and background.

The circadian pattern of stroke occurrence variation has been recognized with certain differences between authors and stroke types. The underlying reason may be related to exogenous factors (cyclic physical activity, including sleep–awake cycles and assuming the up-right posture) and endogenous factors, with their diurnal variation (blood pressure, hemostatic balance, autonomic system activity). The aims of the present study are to investigate the existence of a circadian variation of stroke and the possible differences between stroke subtypes in the Cluj Napoca area.

Materials and method.

The stroke event data were acquired from the Patient Records of a consecutive series of 1083 patients admitted through the Emergency Room at Neurology Departments I and II of the District Hospital of Cluj Napoca, between 1 January 2012 and 31 December 2012. The classifiable onset time was assigned to one of four six-hour intervals: 00.01–06.00 (night), 06.01–12.00 (morning), 12.01–18.00 (afternoon) and 18.01–24.00 (evening). Demographic data and vascular risk factors were recorded.

Results.

All three stroke types (ischemic stroke, hemorrhagic stroke and subarachnoid hemorrhage) have shown a circadian variation regarding their occurrence, with the peak of incidence in the morning and the nadir during nighttime. This circadian pattern is independent by demographic factors and vascular risk factors.

Conclusion.

Our study confirmed the circadian variation of onset occurrence for all stroke subtypes. Some triggering factors promote ischemic stroke and prevent hemorrhagic stroke. The diurnal pattern of variation with the higher incidence in the morning and the lower in the night may lead to chrono-therapeutic and preventive approach (chrono-therapy of the risk factors), which targets the period of the highest vulnerability after awaking.

24-Hour ambulatory blood pressure control with triple-therapy amlodipine, valsartan and hydrochlorothiazide in patients with moderate to severe hypertension

To determine the effectiveness and safety of once-daily combination therapy with amlodipine, valsartan and hydrochlorothiazide for reducing ambulatory blood pressure (ABP) in patients with moderate to severe hypertension, a multicenter, double-blind study was performed (N=2271) that included ABP monitoring in a 283-patient subset. After a single-blind, placebo run-in period, patients were randomized to receive amlodipine/valsartan/hydrochlorothiazide (10/320/25 mg), valsartan/hydrochlorothiazide (320/25 mg), amlodipine/valsartan (10/320 mg) or amlodipine/hydrochlorothiazide (10/25 mg) each morning for 8 weeks. Efficacy assessments included change from baseline in 24-h, daytime and night time mean ambulatory systolic BP (SBP) and diastolic BP (DBP). Statistically significant and clinically relevant reductions from baseline in all these parameters occurred in all treatment groups (P<0.0001, all comparisons versus baseline). At week 8, least squares mean reductions from baseline in 24-h, daytime and night time mean ambulatory SBP/DBP were 30.3/19.7, 31.2/20.5 and 28.0/17.8 mm Hg, respectively, with amlodipine/valsartan/hydrochlorothiazide; corresponding reductions with dual therapies ranged from 18.8–24.1/11.7–15.5, 19.0–25.1/12.0–16.0 and 18.3–22.6/11.1–14.3 mm Hg (P⩽0.01, all comparisons of triple versus dual therapy). Treatment with amlodipine/valsartan/hydrochlorothiazide maintained full 24-h effectiveness, including during the morning hours; all hourly mean ambulatory SBP and mean ambulatory DBP measurements were ⩽130/85 mm Hg at end point. Amlodipine/valsartan/hydrochlorothiazide combination therapy was well tolerated. Once-daily treatment with amlodipine/valsartan/hydrochlorothiazide (10/320/25 mg) reduces ABP to a significantly greater extent than component-based dual therapy and maintains its effectiveness over the entire 24-h dosing period.

Diurnal blood pressure variation and related behavioral factors

Blood pressure (BP) varies according to many internal and external factors, and behavioral factors have an important role in diurnal BP variation. BP rises sharply on waking in the morning and falls during sleep at night, although it varies throughout the day and night. These changes in BP are closely related to mental and physical activities, and the sympathetic nervous system mainly contributes to the diurnal variation in BP. Other behavioral factors, such as food consumption and obesity, dietary intake of sodium, drinking and smoking habits, consumption of coffee and tea, and bathing, also affect the diurnal variation in BP. Alterations in diurnal BP variation due to behavioral factors are frequently seen in patients with hypertension and can be classified as morning hypertension, daytime hypertension and nighttime hypertension. Appropriate lifestyle modifications may normalize or improve both the level and rhythm of BP in these patients.

Choosing among renin-angiotensin system blockers for the management of hypertension: from pharmacology to clinical efficacy

BACKGROUND

Hypertension is an important healthcare challenge, yet despite initiatives to improve detection and advances in therapy, the majority of patients do not achieve recommended blood pressure targets and remain at high cardiovascular risk. Physicians are confronted with an array of antihypertensive agents, accompanied by increasingly complex and often conflicting evidence regarding their efficacy and tolerability.

SCOPE

An extensive PubMed and Cochrane database search was conducted to identify clinical literature (published 1990-2009) on the blood pressure lowering efficacy, tolerability and target organ protection of angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs). While not a systematic review, this article reviews the best available evidence in an attempt to clarify current uncertainty within medical practice regarding treatment options in patients with hypertension.

FINDINGS

ACEIs have been at the forefront of hypertension therapy for several years, especially in hypertensive at-risk patients. However, their use is restricted by burdensome side-effects and their limited ability to reach target blood pressure. Newer ARBs, such as telmisartan, have more sustained blood pressure control throughout the 24-h dosing period compared with ACEIs and other ARBs. For uncomplicated hypertension, ARBs are preferred to ACEIs because of their superior tolerability and adherence. In specific patient populations, namely heart failure patients, ARBs have previously shown equal cardiovascular protection to ACEIs. ONTARGET showed that an ARB, in this case telmisartan, was as effective as ramipril in reducing cardiovascular events in a wide cross-section of at-risk cardiovascular patients, but was better tolerated even though patients were screened for ACEI tolerance.

CONCLUSION

Telmisartan is currently the only ARB to have demonstrated equivalence to ramipril in reducing cardiovascular events in a broad patient population. In practical terms, telmisartan is superior to the reference standard ramipril because of more powerful blood pressure lowering and superior tolerability. However, in many countries, guidance to physicians prioritizes ACEIs. In these countries, telmisartan should be the first choice ARB for hypertensive at-risk patients who do not achieve adequate blood pressure control with an ACEI, or for whom tolerability is a concern.

Magnitude of the early morning blood pressure surge in untreated hypertensive patients: a pooled analysis

OBJECTIVES

A post hoc analysis was performed to assess the magnitude of the early morning blood pressure surge (EMBPS), which is associated with peak cardiovascular risk, in untreated hypertensive patients enrolled in two sister studies (Prospective, Randomised Investigation of the Safety and efficacy of MICARDIS vs. ramipril using ambulatory blood pressure monitoring I and II) with identical design.

METHODS

In adults with a mild-to-moderate primary hypertension and no significant comorbidities, 24-h ambulatory blood pressure monitoring was conducted after a 2- to 4-week placebo run-in period and before treatment initiation. Individual blood pressure measurements at 20-min intervals were analysed.

RESULTS

In 1419 hypertensive patients with normal sleeping times, blood pressure displayed a typical circadian rhythm, with a mean EMBPS of 29/24 mmHg. An EMBPS of >or= 25 mmHg was observed in around 60% of patients. The surge was significantly increased with smoking, alcohol consumption, longer sleep, later waking times, and increased blood pressure variability during waking and sleeping. The magnitude of the EMBPS was significantly reduced in Black vs. White patients. The surge was not affected by gender, body mass index or duration of hypertension. Further analysis showed that ethnicity, alcohol consumption and smoking were all found to have a significant impact on surge around waking and age, sleep duration and sleep blood pressure variability were all found to have an effect on the prewake surge.

CONCLUSIONS

In untreated hypertensive patients, the magnitude of the EMBPS is significant when compared with the 24-h mean and is affected by individual patient characteristics. In light of these findings, physicians should understand the importance of 24-h blood pressure control and the modification of certain lifestyle factors as ways of reducing the EMBPS.

The relationship between nighttime dipping in blood pressure and cerebral hemodynamics in nonstroke patients

Inadequate dipping in nighttime blood pressure (BP) is associated with cerebrovascular disease. The authors aimed to determine whether inadequate nocturnal dipping was associated with abnormalities in cerebrovascular hemodynamics in individuals without stroke. Participants in this study underwent 24-hour ambulatory BP monitoring followed by morning transcranial Doppler measurements of blood flow velocities (BFVs) in the middle cerebral artery during supine rest, head-up tilt, hypocapnia, and hypercapnia. Nighttime BP decline by <10% was considered nondipping. Of the 102 nonstroke participants (mean age, 53.6 years), 35 (34%) were dippers. Although nondippers had similar BFV and cerebrovascular resistance (CVR) while supine, they had a lower BFV (P=.04) and greater CVR (P=.02) during head-up tilt compared with dippers. Moreover, greater nighttime dipping in both systolic BP (P=.006) and diastolic BP (P=.03) were associated with higher daytime BFV and lower CVR (P=.01 for systolic BP; P=.02 for diastolic BP). Inadequate nocturnal BP dipping is associated with lower daytime cerebral blood flow, especially during head-up tilt.