Nocturnal Non-dipping Pattern Research Articles

Capillary vascular density in the retina of hypertensive patients is associated with a non-dipping pattern independent of mean ambulatory blood pressure.

A nocturnal non-dipping pattern has been associated with hypertension-mediated organ damage (HMOD), morbidity and mortality. Retinal imaging through application of modern technologies including optical coherence tomography angiography (OCT-A) can provide detailed insights into early vascular damage. In this observational study, we investigated the relationship of microscopic vascular density in the retina measured with OCT-A and nocturnal blood pressure (BP) dipping. Retinal OCT-A and ambulatory BP monitoring (ABPM) data prospectively obtained from 142 patients referred to a tertiary hypertension clinic were analysed with regression models for associations between BP night-time dipping and retinal capillary vascular density in three different zones around the fovea. More pronounced nocturnal SBP and DBP dipping was significantly associated with increased vascular density in the central foveal area of the retina. These associations were robust to adjustment for other available risk factors including mean daytime BP. Parafoveal and whole image vascular density did not show equivalent significant associations with nocturnal BP dipping. The results were reproducible when assessed in a subgroup of patients who had concomitant type 2 diabetes. Foveal vascular density was associated with the nocturnal BP dipping pattern in hypertensive patients. These associations were robust to adjustment of relevant factors such as daytime BP. Our findings highlight the importance of nocturnal BP features reflected in ambulatory BP monitoring in the assessment of HMOD. Whether routine assessment of retinal damage markers may improve risk management of hypertensive patients remains to be determined.

P275 Uncontrolled post-clinic blood pressure readings can identify nocturnal non-dipping blood pressure pattern

Abstract Funding Acknowledgements Aga Khan University Faculty of Health Sciences Research Committee (#80096) On Behalf PC BP (Post Clinic Blood Pressure) Study Group Background Nocturnal non-dipping increases cardiovascular morbidity and mortality in both hypertensive and normotensive subjects. Ambulatory blood pressure monitoring(ABPM) can identify nocturnal blood pressure(BP) dipping patterns but clinic BP cannot. We previously showed that 15-minute post-clinic BP correlates well with 24- hour ABPM. Purpose We aimed to determine if 15-minute post-clinic BP reading helped to identify patients with nocturnal non-dipping pattern. Methods A cross-sectional study involving 150 participants, as part of the Post Clinic-Ambulatory Blood Pressure(PC-ABP) study, was conducted in cardiology clinics. Participants aged ≥18 years, with hypertension or those referred for its assessment, were included. Pregnant females were excluded. Post-clinic BP was taken 15 minutes after the patient-physician encounter in the clinic using an automated, validated BP device by a research assistant. All the participants were then referred for 24-hour ABPM. Patterns of nocturnal dipping were studied amongst groups of controlled(<140 mmHg) and uncontrolled(≥140mmHg) post-clinic systolic BP(SBP). Fischer exact test was used to determine the difference in dipping patterns amongst the two groups. Results The mean age of participants was 60.3 ± 11.9 years. Of 150 participants, 49% were male and of all, 76% were hypertensive. Mean nighttime SBP(±SD) was 121.9(±18) mmHg(p-value <0.001). Mean nighttime DBP(±SD) was 68.7(± 8.7) mmHg(p < 0.001). Patterns of nocturnal dipping amongst patients with mean post-clinic SBP <140mmHg versus ≥140mmHg has been shown in Table 1. The difference in nocturnal dipping patterns between the two groups was statistically insignificant(p-value 0.071). Pearson correlation coefficient between post-clinic SBP and nighttime SBP for patients with loss of dip was higher (0.64; p < 0.001) whereas it was 0.56(p-value <0.001) for those with preserved dip. Conclusion Uncontrolled post-clinic BP can help in identifying patients with nocturnal non-dipping. Larger studies can help determine the prognostic value of post-clinic BP amongst patients with nocturnal non-dipping. Nocturnal Dipping Amongst The Two Groups Controlled PC SBP <140mmHg (n = 80) Uncontrolled PC SBP ≥140mmHg (n = 70) Preserved Nocturnal Dipping (10 to 20% nocturnal drop in SBP) 61.2% (n = 49) 47.1% (n = 33) Loss of Dip (>0% to <10% of nocturnal drop in SBP) 33.8% (n = 27) 48.6% (n = 34) Reversed Dip (≤0% drop in SBP) 5% (n = 4) 1.4%(n = 1) Excessive Dip (>20% drop in SBP) 0 2.9% (n = 2) Table 1 shows the patterns of nocturnal dipping amongst patients with controlled (<140mmHg) and uncontrolled (≥140mmHg) 15-minute post-clinic systolic blood pressure (PC SBP).

PULSE WAVE VELOCITY NON-DIPPING PATTERN IS ASSOCIATED WITH CARDIOVASCULAR MORTALITY IN HYPERTENSIVE PATIENTS UNDERGOING CHRONIC HEMODIALYISIS

Objective: Increased arterial stiffness is established as an independent cardiovascular (CV) risk factor. Although this association was found also in patients undergoing hemodialysis (HD), reports are frequently contradictory largely because measurements were obtained shortly before or after HD. The aim of our study was to analyze circadian variations of aortic stiffness using ABPM device which provides valid measures in ambulatory conditions and association with CV mortality. Design and method: A total of 31 hypertensive patients (19 M, 12 F; averaged age 59.4) who had been on intermittent HD treatment for more than 6 months were enrolled in this study (22.6% diabetic, 16.1% smokers) and followed up for average 18.6 months. Patients received HD treatment 4 hr/session three times a week during the study period. TensioMed Arteriograph which records oscillometric BP and pulse waveforms at the brachial artery and provides valid measures of aortic BP, AIx, and PWV in ambulatory conditions was applied on non-dialysis midweek day. Control group consist of 25 healthy subjects without prior diabetes, CKD, hypertension and hyperlipidemia. Results: Systolic BP, PWV and AIx non-dipping patterns were found in 74.2%, 64.5% and 61.3% of patients. We failed to find difference in AIx dipping pattern between patients and control subjects (38.7% vs. 28.0%; p = 0.4) while PWV non-dipping pattern was significantly more frequently found in HD patients (64.5% vs. 16.0%, p < 0.001). At the end of follow-up period 13 (41.9%) patient died from CV deaths. We have not found any differences in age, dialysis parameters, comorbidity, HD therapy and laboratory parameters between survived and deceased HD patients. Differences in basal systolic and diastolic BP, PWV, AIx between survived and deceased were not statistically significant. There were no differences in number of BP and AIx non-dippers between survived and deceased patients while significantly higher number of deceased patients had PWV nocturnal non-dipping pattern (84.5% vs.50.0%, p = 0.04). Conclusions: A newly introduced ABPM devices for ambulatory recordings provide new insights on importance of arterial stiffnes for CV moratlity in patients undergoing HD. Our results showed that PWV non-dipping pattern is independently associated with CV moratily.

Serum Uric Acid, Inflammation, and Nondipping Circadian Pattern in Essential Hypertension

Uric acid (UA) is independently associated with the emergence of hypertension. Nocturnal nondipping pattern of hypertension is associated with a greater risk of cardiovascular, renal, and cerebrovascular complications than dippers. The aim of the present study was to evaluate the relationship between the circadian blood pressure rhythm and UA level in patients with newly diagnosed essential hypertension. The study included 112 essential hypertensive patients and 50 healthy controls. The hypertensive patients were divided into two groups according to the results of 24-hour ambulatory blood pressure monitoring, including 60 dippers (35 men, 25 women; mean age, 52.6±15.8 years) and 52 nondippers (29 men, 23 women; mean age, 55.9±13.2 years). Nondippers had significantly higher serum UA levels than the dippers and controls (5.8±0.8, 5.1±0.9 and 4.2±0.9 mg/dL, respectively; P<.001). Serum high-sensitivity C-reactive protein levels were also significantly higher in the nondipper group than the other groups (P<.001) and significantly correlated with serum UA (r=0.358, P<.001). Multivariate logistic regression analysis revealed an independent positive association between serum UA levels and nondipper pattern (odds ratio, 2.28; 95% confidence interval, 1.33-3.94; P=.003). Serum UA is strongly and independently associated with the nondipper circadian pattern in essential hypertension.

Circadian blood pressure variation in patients with type 2 diabetes – relationship to macro- and microvascular subclinical organ damage

Aims To explore the association between nocturnal blood pressure (BP) dipper status and macro- and microvascular organ damage in type 2 diabetes. Methods Cross-sectional data from 663 patients with type 2 diabetes, aged 55–66 years, were analysed. Nurses measured office BP and ambulatory BP during 24 h. Individuals with ≥10% difference in nocturnal systolic blood pressure (SBP) relative to daytime values were defined as dippers. Non-dippers were defined as <10% nocturnal decrease in SBP. Estimated glomerular filtration rate (GFR) was calculated and microalbuminuria was measured by albumin:creatinine ratio (ACR). Aortic pulse wave velocity (PWV) was measured with applanation tonometry over the carotid and femoral arteries. Results We identified 433 dippers and 230 subjects with a nocturnal non-dipping pattern. Nocturnal SBP dipping was independently of office SBP associated with decreased PWV ( p = 0.008), lower ACR ( p = 0.001) and NT-proBNP ( p = 0.001) and increased GFR ( p < 0.001). Conclusions We conclude that diurnal BP variation provides further information about early macro- and microvascular subclinical organ damage that goes beyond standardized office BP measurements in patients with type 2 diabetes.

Neurofibromatosis type 1 (NF1) and pheochromocytoma: prevalence, clinical and cardiovascular aspects

The aim of the study was to evaluate the prevalence of pheochromocytoma (PHEO) in patients with neurofibromatosis type 1 (NF1), and to analyze the behavior of some anthropometric and cardiovascular parameters. In 48 consecutive NF1 patients, urinary metanephrines and vanillylmandelic acid excretion were assessed. The body mass index (BMI), waist circumference (WC), ambulatory blood pressure monitoring (ABPM), echocardiography and ultrasound carotid arterial wall evaluation were performed. In NF1 patients, 11 (29.3%) had arterial hypertension, 7 (14.6%) had a PHEO. Four (57%) NF1 patients with PHEO were symptomatic at the diagnosis. In PHEO-NF1 patients, we revealed a lower BMI and WC values with respect to NF1 patients without PHEO and normal subjects (NSs) (p<0.05), respectively. The nocturnal non-dipping pattern at the ABPM was present in 40.4% of NF1 patients, and in particular this phenomenon was present in PHEO-NF1 patients (71.4%). Left ventricular mass index and intima media thickness were significantly higher in NF1 patients as compared to NS (p<0.05), particularly in NF1-PHEO patients (p<0.05). In conclusions, these findings revealed high prevalence of PHEO in NF1 patients and suggest that, in addition to blood pressure, humoral factors (increased sympathetic activity or neurofibromin), influence the pathogenesis of remodeling of cardiovascular system.

Short-term Reproducibility of Nocturnal Non-dipping Pattern in Recently Diagnosed Essential Hypertensives

Objective : To investigate in a selected population of patients with a recently diagnosed essential hypertension the short-term intrasubject variability of diurnal changes in blood pressure (BP). Methods : Two hundred and eight consecutive, recently diagnosed, never treated essential hypertensives (119 men, 89 women, 46 - 12 years) underwent 24-h ambulatory BP monitoring (ABPM) twice within 3 weeks. Dipping pattern was defined as a reduction in average systolic and diastolic BP at night greater than 10% compared to average daytime values. Results : 177 subjects (85%) showed no change in their diurnal variations in BP. Of the 159 subjects who had a dipping pattern on first ABPM, 134 (90.6%) confirmed this type of profile on the second ABPM, while 15 (9.4%) showed a non-dipping pattern. Of the 59 subjects who had a non-dipping pattern on the first ABPM, 43 (72.2%) confirmed their initial profile on the second ABPM, while 16 (28.8%) did not. Conclusion : These findings indicate that short-term reproducibility of diurnal changes in BP in early phases of untreated essential hypertension, characterized by a large prevalence of dipping pattern, is overall satisfactory. However, our study underlines that also in this particularly selected population of hypertensives the definition of non-dipping status on the basis of a single ABPM remains unreliable in about one-third of patients.

What are the influences of salt, potassium, the sympathetic nervous system, and the renin-angiotensin system on the circadian variation in blood pressure?

Nocturnal blood pressure patterns are expressed as a consequence of both intrinsic circadian rhythms and the quantity and quality of sleep. A range of neurohumoral factors have been either inferred or definitively proven to influence the circadian blood pressure pattern. In this regard, changes in atrial natriuretic peptide, plasma renin activity and plasma aldosterone have been evaluated as to the influence each might have in determining diurnal blood pressure patterns. As an example, a clear pattern of nocturnal increase in plasma renin activity has been observed; however, the relationship between this change and nocturnal blood pressure remains vague. In contrast, change in sympathetic nervous system activity has most commonly been associated with the conversion of a pattern of nocturnal dips in blood pressure to one of non-dipping. Increasingly, dietary intake patterns, characterized by high sodium or low potassium content, or both, are recognized as modifiers of the normal decrease in nocturnal blood pressure, again in favor of producing a non-dipping pattern. The impact of these nutritional patterns on nocturnal blood pressure change is recognized to be most prominent in salt-sensitive individuals. Modifications of dietary sodium intake, such that it is decreased or potassium intake is increased, or both, are now recognized as means by which a nocturnal non-dipping pattern can be converted to a dipping pattern. Additional studies of an integrative nature will be necessary to obtain more complete definition of the dynamic interplay between nutrition and various neurohumoral axes in determining how nocturnal blood pressure patterns are expressed.