Abnormal Circadian Blood Pressure Profile Research Articles

Abnormal Circadian Blood Pressure Variation is Associated with SYNTAX Scores in Hospitalized Patients with Acute Coronary Syndrome.

ResumoFundamento Menor redução da pressão arterial (PA) noturna, conhecida como hipertensão não-dipper, é um forte preditor de morbimortalidade cardiovascular.Objetivos Este estudo visou investigar a relação entre a hipertensão não-dipper e a gravidade e complexidade da doença arterial coronariana usando o escore SYNTAX em pacientes hospitalizados com síndrome coronariana aguda.Métodos Foram selecionados 306 pacientes consecutivos com síndrome coronariana aguda. Pacientes clinicamente estáveis internados na unidade de terapia intensiva intermediária pelo menos 24 horas após a angiografia e/ou revascularização bem sucedida. Após os critérios de exclusão, foram incluídos 141 pacientes (34 mulheres e 107 homens; idade média 61 ± 11 anos). A hipertensão não-dipper foi definida como uma queda de 0% a 10% na PA sistólica média durante a noite em comparação com o dia, medida em intervalos de 1 hora, usando o mesmo dispositivo automático de medição de PA em monitores de beira de leito (Vismo PVM-2701; Nihon Kohden Corp., Tóquio, Japão). O escore SYNTAX foi calculado com uma calculadora online. Os preditores independentes do escore SYNTAX foram avaliados por meio de análise de regressão logística multivariada. P < 0,05 foi considerado estatisticamente significativo.Resultados Os pacientes com hipertensão não-dipper apresentaram escore SYNTAX maior do que os pacientes com hipertensão dipper (11,12 ± 6,41 versus 6,74 ± 6,45, p < 0,0001). Em um modelo de regressão logística multivariável, o status de hipertensão não dipper (odds ratio: 5,159; intervalo de confiança de 95%: 2,246 a 11,852, p < 0,001), sexo (p = 0,012) e colesterol de lipoproteína de baixa densidade (p = 0,008) emergiram como preditores independentes de alto escore SYNTAX.Conclusões Os resultados do nosso estudo fornecem um possível mecanismo adicional ligando o perfil anormal da PA circadiana à gravidade e à complexidade da doença arterial coronariana em pacientes com síndrome coronariana aguda.

Ambulatory blood pressure monitoring and subclinical inflammation in children with chronic kidney disease

Background. Children with chronic kidney disease (CKD) are characterized by increased risk of hypertension and chronic low-grade inflammation. The aim of the study was the analysis of relation between parameters of ambulatory blood pressure monitoring (ABPM) and subclinical inflammation in children with CKD. Material and methods. Study group included 27 paediatric patients (age 14.23 ± 3.57 years) with CKD stage 2–5; 18 children with previously recognized hypertension. In all patients we evaluated ABPM, office blood pressure, complete blood count and selected clinical and biochemical parameters. Results. In the study group, GFR was from 7.05 to 86.73, mean 40.88 ± 25.82 mL/min/1.73 m 2 . All 9 children without hypertension had normal blood pressure in ABPM, but ABPM detected poor blood pressure control in 7 among 18 (38.9%) children with previously recognized and treated hypertension. Abnormal circadian blood pressure profile was found in 12 (44.4%) children: 9/18 (50.0%) with hypertension and 3/9 (33.3%) with normal BP. Systolic, diastolic, mean blood pressure and diastolic blood pressure load correlated with neutrophil count, neutrophilto- lymphocyte ratio and platelet-to-lymphocyte ratio (r = 0.39–0.49, p = 0.010–0.044); diastolic and mean blood pressure and diastolic blood pressure load with parathormone (r = 0.48–0.57, p = 0.005–0.023); diastolic blood pressure load with phosphate and calcium-phosphorus product (r = 0.44–0.47, p = 0.021-0.030); diastolic blood pressure dipping with phosphate (r = –0.43, p = 0.034). Conclusions. 1. Ambulatory blood pressure monitoring should be used in children with chronic kidney disease on a regular basis, especially in those with arterial hypertension. 2. Blood pressure in children with chronic kidney disease may be related to degree of subclinical inflammation.

Markers of chronic kidney disease in high-risk hypertensive patients: relationship with abnormal circadian blood pressure profile and intrarenal vascular resistance

Objective. To determine the frequency of markers of chronic kidney disease (CKD) in hypertensive patients, and to assess their relationship with the circadian blood pressure (BP) profile and intrarenal vascular resistance.Design and Methods. We studied 70 patients with medically-controlled hypertension (63,2 ± 8,3 years, m — 48,6 %, office BP was 130,5 ± 13,7 / 78,1 ± 8,5 mm Hg), 40 patients were recruited from the Russian multicentre program CHRONOGRAF. Measurement of the office BP, ambulatory BP monitoring were performed. Glomerular filtration rate (GFR) was calculated using the CKD-EPI formula, and albuminuria (AU) was determined as albumin/creatinine (A/Cr) ratio in the morning portion of urine (n = 40) or 24-hour urinary albumin excretion (UAE) (n = 22). Intrarenal vascular resistance was estimated by renal duplex Doppler ultrasound. The resistive index (RI) levels in the main renal arteries (MRA) and intrarenal arteries (IRA) were calculated.Results. Markers of CKD (GFR &lt; 60 ml/min/1,73 m2and/or A/Cr &gt; 30 mg/g and/or UAE &gt; 30 mg/day) were detected in 31,4 % of patients with well-medically-controlled hypertension: average values of BP-day and BP-night were normal. The frequency of markers of CKD was 44,4 % in patients with BP-night ≥ 120/70 mm Hg (40,9 %) and 28,2 % in patients with BP-night &lt; 120/70 mm Hg (58,1 %). A/Cr ratio was positively associated (Rs = 0,3550, р = 0,0266), GFR was negatively associated (Rs = –0,3795, р = 0,002) with systolic BP-night. RI in the segmental intrarenal arteries correlated with GFR (Rs = –0,4232, p = 0,0005). Renal RI were higher in CKD-patients vs. non-CKD-patients. During the ROC-analysis, the threshold value of RI in segmental IRA 0,725 to the detection of CKD markers (sensitivity of 71,4 %, specificity of 68,9 %, AUC = 0,699) was established. Among the diabetic patients, there were more marked disturbances of renal hemodynamic in the presence of CKD markers: RI in arcuate IRA reached 0,73 (0,68–0,75).Conclusions. The high frequency of markers of CKD (31,4 %) was identified even in patients with well-medically-controlled hypertension, it was associated with systolic BP-night. The negative correlation was found between GFR and RI. Renal hemodynamics was significantly disturbed in the presence of CKD markers, especially in patients with type 2 diabetes mellitus. The cut-off point of RI in segmental IRA indicating the CKD markers is 0,725.

Impact of abnormal circadian blood pressure profile on left atrial function assessed by 2D speckle tracking echocardiography and its effect on the functional capacity of hypertensive patients

Background The left atrial (LA) function has an important role in hypertension as it is strongly predictive of adverse cardiac events and death, assessment of the circadian blood pressure (BP) profile is more predictive than assessment of the office BP reading in estimating the cardiovascular risk. The 2D speckle tracking echocardiography (2D-STE) provides more insight into early hypertension-induced LA dysfunction. Aim The aim of this work is to assess the impact of abnormal circadian BP profile on LA function using 2D-STE and its effect on functional capacity in hypertensive patient with preserved ejection fraction assessed by conventional echocardiography. Patients and methods This work included 60 consecutive hypertensive patients with preserved ejection fraction by conventional echocardiography [mean age 48±5 years and body surface area (BSA) 1.9±1.1] they were classified into two groups according to the data derived from 24 h ambulatory BP, group 1: dipper group that included 28 patients (mean age 48±8 years and BSA 1.9±0.1) and group 2: nondipper group that included 32 patients (mean age 50±6 years and BSA 1.9±0.09). All patients were evaluated by comprehensive 2D and Doppler echocardiographic techniques, TDI and 2D-STE, ambulatory BP, and stress. Myocardial perfusion imaging using treadmill exercise test was done to exclude coronary artery disease (CAD) and to assess the functional capacity. Results The results showed a statistically high significant decrease in the average peak left atrial global longitudinal strain in group 2 (the nondipper group) (group 1=26±4 vs. 20.4±3.5 in group 2, P&lt;0.00), and a statistically significant decrease in the functional capacity parameter using treadmill metabolic equivalents (METs) in group 2 (group 1=7.3±1.4 vs. 6.2±0.8 in group 2, P&lt;0.01) in comparison with group 1. Also we found a significant positive correlation between the average peak atrial longitudinal strain and the functional capacity assessed by treadmill stress test (r=0.424, P=0.05). There were no other significant differences between the two groups with respect to other LA parameters by conventional echo Doppler, TDI, and 2D-STE. Conclusion Abnormal circadian BP profile add more deleterious effect on LA function in hypertensive patients as detected by 2D-STE that denotes more decrease in functional capacity and worse cardiac events.

Abnormal Circadian Blood Pressure Profile as a Prognostic Marker in Patients with Nonischemic Dilated Cardiomyopathy

Objectives: An abnormal circadian blood pressure (BP) profile is considered a risk factor for cardiovascular disease. However, its significance in heart failure patients with nonischemic etiology is unknown. Herein, we investigated the prognostic value of a circadian BP profile in patients with nonischemic dilated cardiomyopathy (NIDCM). Methods: We enrolled 114 NIDCM patients (76 males, mean age 53.1 years). The percent nighttime BP fall (%NBPF) was defined using ambulatory BP monitoring as a percent decrease in mean systolic BP in nighttime from daytime. All patients were divided into three groups: dipper (%NBPF ≥10), non-dipper (0 ≤ %NBPF < 10), and riser (%NBPF <0). Results: Riser patients had the highest serum creatinine levels (dipper, 0.78 ± 0.20 mg/dl; non-dipper, 0.85 ± 0.21 mg/dl; riser, 0.99 ± 0.23 mg/dl; p = 0.006). In survival analysis, riser patients had the highest cumulative cardiac-related deaths (log-rank, p = 0.001), which was an independent predictor of cardiac-related deaths (hazard ratio, 12.6; 95% confidence interval, 1.76-253; p = 0.01). Multivariate analysis revealed that the norepinephrine level at 24-hour collected urine (24 h U-NE) and the serum creatinine level were independent determinants of %NBPF (adjusted R² = 0.20; 24 h U-NE, p = 0.0001; serum creatinine, p = 0.04). Conclusions: The riser profile was associated with poor prognosis of NIDCM, which may reflect impaired sympathetic nervous system activity. Evaluating the circadian BP profile may be useful for risk stratification in NIDCM patients.

Arterial stiffness and carotid arteries: correlation with daily blood pressure profile in essential hypertension

Objective. To study the relationship between arterial stiffness, augmentation index and the structure of the carotid arteries with daily blood pressure (BP) profile in patients with essential hypertension (HTN). Design and methods. Altogether 155 patients with HTN aged 30–70 years were examined. A physical examination, glucose, creatinin level and lipid profile (low- and high-density lipoproteins, and triglycerides) (biochemical analyzer Sinсhron SX‑4 DELTA, Beckman, USA), duplex scanning of carotid arteries (Sequoia‑512, Acuson, USA), and arterial stiffness assessment by pulse wave contour analysis (Angioscan‑01, Angioscan, Russia) were performed. Results . Augmentation index was associated with the nocturnal BP reduction in hypertensive males, but not females. In males, augmentation index was 6,8 ± 11,5 %, 12,7 ± 10,9 % and 14,5 ± 7,7 % for the dippers, nondippers and night-peakers, respectively (p 0,05). The lowest values of augmentation index (15,6 ± 14,8 % versus 21,6 ± 13,4 % for non-dippers, p < 0,02) were found in patients with normal circadian BP profile. In addition, more severe carotid atherosclerotic lesions were found in non-dippers (23,2 ± 18,8 %) compared to dippers (13,7 ± 14,5 %, p < 0,01). Conclusions . Patients with HTN and abnormal circadian BP profile show higher augmentation index and more severe atherosclerotic lesions in carotid arteries.

Prognosis in Relation to Blood Pressure Variability

Prognosis in Relation to Blood Pressure Variability

Variability of circadian blood pressure profile during 24-hour ambulatory blood pressure monitoring in hypertensive patients

Evaluation of circadian blood pressure (BP) profile is an important element of ambulatory BP monitoring (ABPM). Abnormal nocturnal fall in BP is more common in patients with secondary causes of hypertension and in the elderly. Cardiovascular risk is substantially increased in these patients. Analysis of circadian BP profile in a population of treated hypertensives and identification of factors affecting variability of nocturnal fall in BP. 24-h ABPM was performed in hypertensive patients. Based on nocturnal fall pattern, four subgroups were identified:dippers, non-dippers, extreme dippers, and risers. Comorbidities were assessed, and data obtained in all groups were compared with the dipper profile group. We analysed 161 patients (86 men, 53.4%). A dipper profile was noted in 44.7% of patients. Abnormal circadian BP profile was observed in 55.3% of patients, including a non-dipper profile in 21.1% of patients, an extreme dipper profilein 32.3% of patients, and a riser profile in 1.9% of patients. No significant differences in the rates of dyslipidaemia, previous myocardial infarction, previous stroke, and coronary artery disease were seen between the groups. The whole study population was also characterised by similar rates of excessive body weight and abdominal obesity. An abnormal circadian BP profile was found in over 50% of hypertensive patients. A negative correlation was found between nocturnal BP fall and the patient age. No differences were found between groups with different circadian BP pattern regarding duration of hypertension and the presence of dyslipidaemia, obesity, diabetes, or coronary artery disease.

CHANGES IN THE PARAMETERS OF 24-HOUR BLOOD PRESSURE MONITORING AND ARTERIAL STIFFNESS IN PATIENTS WITH HYPERTENSION AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE TREATED WITH VALSARTAN

Aim. To study changes in the parameters of the 24-hour blood pressure (BP) monitoring and arterial stiffness (AS) in patients with arterial hypertension (HT) and chronic obstructive pulmonary disease (COPD) treated with angiotensin II receptors blocker, valsartan. Material and methods. Men with HT and COPD (n=23), who have been receiving valsartan with starting dose 80 mg/day for 6 months as antihypertensive therapy were included into the study. If target BP was not achieved, correction of the valsartan dose was carried out with the hydrochlorothiazide addition when needed. Clinical examination, 24-hour BP and AS monitoring using BPLab MnSDP-2 monitor ("Petr TELEGIN",Russia), clinical evaluation of COPD were performed. Results. Abnormal circadian BP profile and the elastic properties of arteries were diagnosed in the majority of hypertensive patients with COPD. Valsartan therapy allowed to achieve target BP levels in 100% of patients, normalization of circadian BP profile in 56.5%, improvement in AS parameters: a significant increase in PTT2 (from 89.6±14.3 to 94.4±18.4 ms), reduction of (dP/dt)max (from 566.6±117.9 to 518.8±146.2 mmHg/s), AIx (from -4.0±15.2 to -11.6±20.8 %) as compared to the baseline. Circadian changes in daily parameters of AS in studied patients with the most obvious night-time abnormalities of the elastic properties of arteries were detected. Valsartan intake led to Alx reduction at night-time. Conclusion. Valsartan-based therapy in hypertensive patients with concomitant COPD demonstrated a high antihypertensive efficacy and favorable changes in the elastic properties of the vascular wall that confirm its organoprotective effect.

CIRCADIAN BLOOD PRESSURE PROFILE AND LEFT VENTRICULAR DIASTOLIC DYSFUNCTION IN CHRONIC PROSTATITIS

Objective.To study the relationship between diastolic left ventricular dysfunction and the circadian bloodpressure prof le in patients with chronic prostatitis.Design and methods.Eighty-two patients with chronic prostatitis underwent ambulatory blood pressure monitoring and echocardiography.Results and conclusion.The disturbances of circadian blood pressure profile in patients with chronic prostatitis include the abnormal nocturnal decrease in systolic and/or diastolic blood pressure, instable nocturnal systolic hypertension and an abnormality of the morning blood pressure surge. In patients with abnormal circadian blood pressure profile left ventricular diastolic dysfunction with increased myocardial mass and thickness of the posterior wall of the left ventricle was more prevalent.

High prevalence of nocturnal arterial hypertension and non-dipping in lung transplant recipients

Objective— An abnormal circadian blood pressure (BP) profile is associated with adverse cardiovascular and all-cause outcomes. It is highly prevalent after heart, liver and kidney transplantation. We aimed to assess the prevalence of an abnormal ambulatory BP pattern in lung transplant recipients (LTx).Methods— Ambulatory BP monitoring (ABPM) was performed in 53 LTx and compared to those of 42 control subjects matched for age, gender and daytime BP. In 19 patients in whom at least two recordings were performed, we compared the first and the last one.Results— The non-dipping pattern (a less than 10% reduction in nocturnal BP) was more prevalent in LTx than in control subjects (89 versus 64%, P < 0.01). Nighttime BP was higher in LTx than in control subjects (P < 0.01 and < 0.001 for systolic BP (SBP) and diastolic BP (DBP), respectively). The nocturnal reduction of BP was lower in LTx than in control subjects (3 versus 8% for SBP and 6 versus 13% for DBP, both P < 0.001). These results remained significant after adjustment for the presence of diabetes mellitus and creatinine clearance.In the 19 patients in whom ABPM was performed twice (mean interval between the two recordings was 22 months), ambulatory BP values remained unchanged between the two recordings, although the number of antihypertensive agents was significantly higher.Conclusion— An abnormal circadian BP profile is highly prevalent after lung transplantation. It is observed consistently over prolonged periods of time.

High prevalence of nocturnal arterial hypertension and non-dipping in lung transplant recipients.

An abnormal circadian blood pressure (BP) profile is associated with adverse cardiovascular and all-cause outcomes. It is highly prevalent after heart, liver and kidney transplantation. We aimed to assess the prevalence of an abnormal ambulatory BP pattern in lung transplant recipients (LTx). Ambulatory BP monitoring (ABPM) was performed in 53 LTx and compared to those of 42 control subjects matched for age, gender and daytime BP. In 19 patients in whom at least two recordings were performed, we compared the first and the last one. The non-dipping pattern (a less than 10% reduction in nocturnal BP) was more prevalent in LTx than in control subjects (89 versus 64%, P < 0.01). Nighttime BP was higher in LTx than in control subjects (P < 0.01 and < 0.001 for systolic BP (SBP) and diastolic BP (DBP), respectively). The nocturnal reduction of BP was lower in LTx than in control subjects (3 versus 8% for SBP and 6 versus 13% for DBP, both P < 0.001). These results remained significant after adjustment for the presence of diabetes mellitus and creatinine clearance. In the 19 patients in whom ABPM was performed twice (mean interval between the two recordings was 22 months), ambulatory BP values remained unchanged between the two recordings, although the number of antihypertensive agents was significantly higher. An abnormal circadian BP profile is highly prevalent after lung transplantation. It is observed consistently over prolonged periods of time.

Kidney and Circadian Blood Pressure Rhythm

Association between nondipper pattern of circadian rhythm of blood pressure (BP) and impaired renal capacity to excrete sodium into urine was confirmed by Bankir et al1 in this issue of Hypertension based on a large number of subjects. Although this association has been observed in small studies,2,3 their study1 is the first to show it in a large-scale setting, and, therefore, is highly welcomed. Because there is a tight link between kidney and hypertension, renal dysfunction causes hypertension, whereas hypertension accelerates renal damage. It is well appreciated that the kidneys play an important role in the long-term regulation of BP. Usually it takes almost 1 week for kidneys to achieve a new steady-state balance of sodium, when sodium intake is altered. Therefore, renal participation in the short-term BP regulation, such as circadian rhythm, has been overlooked. However, the findings of Bankir et al1 strongly suggest that nocturnal hypertension and nondipper pattern of circadian BP rhythm are because of impaired renal capacity to excrete sodium, and circadian BP rhythm is at least in part regulated by kidneys. Sodium sensitivity of BP is also determined by renal capacity to excrete sodium and is regulated by glomerulotubular balance between glomerular ultrafiltration capability and rate of tubular sodium reabsorption.4 Thus, sodium sensitivity is increased in chronic kidney disease (CKD) where glomerular filtration rate (GFR) is reduced and also in disorders with enhanced tubular sodium reabsorption, including primary aldosteronism, diabetes mellitus, and metabolic syndrome, where GFR is augmented. When sodium sensitivity is increased, glomerular capillary pressure is usually elevated, resulting in albuminuria and renal damage. It becomes evident that, in patients with high-sodium sensitivity, the nocturnal dip in …

Relation between Serum Calcium, Phosphate, Parathyroid Hormone and ‘Nondipper’ Circadian Blood Pressure Variability Profile in Patients with Normal Renal Function

Background and Aims: In patients with renal disease, an association between abnormal circadian blood pressure profile and abnormalities in bone and mineral metabolism, including vascular calcifications, is well known. However, such a link has not yet been reported in hypertensive patients with normal renal function. We aimed to evaluate if higher serum phosphate, calcium, parathyroid hormone (PTH) level and the calcium×phosphate (Ca×P) product would be associated with a nondipper hypertension, in patients with normal renal function and without any PTH disorder. Methods: 190 hypertensive subjects with the following inclusion criteria were enrolled: (1) normal phosphate and PTH levels; (2) glomerular filtration rate (GFR) >60 ml/min, and (3) no history of calcium, phosphate, vitamin D medication and hyperparathyroidism. Results: Of the total population, 76 patients (40%) were classified as dippers and 114 (60%) as nondippers. Nondipper patients had higher levels of phosphate (3.70 ± 0.61 vs. 3.35 ± 0.44 mg/dl, p = 0.001), Ca×P product (35.4 ± 6.5 vs. 31.5 ± 5.0, p = 0.001) and PTH (75.7 ± 28.8 vs. 46.6 ± 17.1 pg/ml, p = 0.000) compared to dipper patients. Independent predictors (multiple regression) for nondipper hypertension were PTH (β = 0.43, p = 0.001) and phosphate (β = 0.9, p = 0.03). Conclusion: We demonstrate a graded independent relation between higher levels of phosphate, PTH, Ca×P product and the risk of nondipping in hypertensive patients with an estimated GFR of >60 ml/min and normal mineral metabolism.

Hypertension after renal transplantation.

With current immunosuppression, elevated blood pressure is found in almost 90% of renal graft recipients. Major causes of this are impairment of renal function (secondary to chronic allograft nephropathy or less frequently recurrence of primary renal disease), the use of calcineurin inhibitors as immunosuppressants, uncontrolled renin secretion by the shrunken kidneys of the recipient, stenosing lesions of the transplant artery (or the upstream arteries of the recipient), polycythemia, and genetic predisposition to hypertension of the graft donor. Even minor degrees of blood pressure elevation have a significant impact on survival of the recipient and on graft survival, presumably by amplifying vascular injury to the graft. In this respect, elevation of systolic blood pressure and an abnormal circadian blood pressure profile are of particular relevance. In contrast to previous opinion, angiotensin converting enzyme inhibitors are indicated in treatment, but given the causal role of sodium retention and graft vasoconstriction, diuretics and calcium channel blockers remain mainstays of antihypertensive treatment in the renal allograft recipient.

Circadian rhythm of blood pressure in renal disease.

Ambulatory blood pressure (BP) measurement has added a new dimension to the evaluation of abnormal BP in patients with various stages of renal disease. Although there is not complete consensus concerning the definition of normal values, a high prevalence of an abnormal circadian BP profile is noted in patients with essential hypertension with renal involvement (ie, microalbuminuria), in diabetic patients (particularly those with microalbuminuria or overt proteinuria), and in patients with primary chronic renal disease. Studies in diabetic patients point to an important role of both hypervolemia and disturbed autonomic innervation in the genesis of an abnormal circadian BP profile. In both patients with diabetic renal disease and patients with nondiabetic renal disease, retrospective studies suggest that an abnormal nocturnal decline in BP is associated with more rapid progression independent of 24-hour mean arterial pressure. The abnormal circadian BP profile persists in dialyzed patients, is ameliorated by long and frequent dialysis sessions, but is not completely normalized after successful renal transplantation.

Circadian blood pressure variation versus renal function

Several published reports describe an abnormal circadian blood pressure profile in chronic renal failure subjects. Factors other than renal failure, including age, diagnosis of diabetes mellitus, autonomic dysfunction, and race, also may affect circadian blood pressure profiles. To further elucidate the relationship between renal function and circadian blood pressure variation, we compared day/night circadian blood pressure changes in three groups of male veteran hypertensive patients: group A, creatinine clearance (CC) > 80 mL/min, n = 20; group B, CC 20 to 80 mL/min, n = 19; and group C, CC < 20 mL/min, n = 14. We use postural changes in catecholamines, renin, and aldosterone as a measure of autonomic function. No significant difference in day/night percent change in systolic, diastolic, mean arterial pressure (MAP), or heart rate was seen by renal function group. Regression analysis using age, diagnosis of diabetes mellitus, postural hormonal changes, and creatinine clearance found race to be the only significant predictor of the day/night percent change in MAP, ( P < 0.05). Compared with whites, black subjects had higher nocturnal heart rates ( P = 0.01); smaller day/night heart rate changes ( P = 0.03); significantly higher diastolic blood pressure ( P = 0.01); and a trend toward smaller day/night change in diastolic blood pressure ( P = 0.06). In conclusion, renal function level does not influence day/night blood pressure changes. The blunting or reversal of the normal circadian blood pressure pattern seen in some chronic renal failure hypertensive subjects may be attributable to the association between chronic renal failure and cofactors associated with abnormal circadian blood pressure, including black race and possibly severity of atherosclerosis.

Influence of obstructive sleep apnoea on circadian blood pressure profile.

A high prevalence of systemic hypertension in obstructive sleep apnoea (OSA) has been described but data on circadian blood pressure (BP) profile are limited and give inconsistent results. The present study examines 24-h BP in 106 patients referred because of loud snoring or excessive daytime sleepiness in combination with snoring. Patients were classified as OSA (n = 62) or habitual snorers (HS) (n = 44). Respiratory disturbance index (RDI) in OSA was 47 + 24 vs. 2 +/- 2 in HS. Mean age and body mass index in OSA was significantly higher. BP was measured non-invasively at 15-min intervals during a 24-h period. Daytime and night-time BP was higher in OSA compared to HS. BP night/day ratio in OSA was 0.92 +/- 0.07 vs. 0.86 + 0.06 in HS (P < 0.05). To investigate the influence of variables other than breathing abnormalities during sleep on our results we compared BP profiles of 25 OSA and 25 HS matched for sex, age and body weight. Again differences in daytime and night-time BP and BP night/day ratio were significant. Using a value of at least 10% fall in nocturnal BP to describe a regular BP profile (dipper) 68% of OSA were classified as non-dippers vs. 24% of HS. Influence of short-term (2-4 days) nCPAP therapy on circadian BP profile was investigated in 34 patients with OSA. Systolic and diastolic nocturnal (but not daytime) BP was significantly reduced. The percentage of non-dippers was 79% before and 50% after treatment. In conclusion results of this study indicate a causal link between OSA and abnormal circadian BP profile.