Etiology and management of hypertension in chronic kidney disease

Association between pulse pressure and carotid plaques in old adults with uncontrolled hypertension: results from a community-based screening in Hangzhou, China

BACKGROUND

There is a broad pulse pressure (PP) and a high prevalence of carotid plaques in old adults. Previous studies have indicated that PP is strongly associated with carotid plaque formation. This study aimed to explore this association in old adults with uncontrolled hypertension.

METHODS

1371 hypertensive patients aged ≥ 60 years with uncontrolled hypertension were enrolled in a community-based screening in Hangzhou, China. Carotid plaques were assessed using ultrasonography. Logistic regression models were used to estimate the association between PP and carotid plaques by odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Carotid plaques were detected in 639 (46.6%) of subjects. Multiple plaques were found in 408 (63.8%) and soft plaques in 218 (34.1%). Elevated PP was associated with a high prevalence of carotid plaques. After adjusting for traditional risk factors, compared to patients within the lowest tertile of PP, those within the highest tertiles had an increased risk of carotid plaques (OR 2.061, CI 1.547-2.745). For each 1-SD increase, the risk increased by 40.1% (OR 1.401, CI 1.237-1.587). There was a nonlinear association between PP and carotid plaques (P nonlinearity = 0.039). The risk increased rapidly after the predicted PP level reached around 60 mmHg. The associations were stronger among participants with multiple and soft plaques.

CONCLUSIONS

Our findings suggested that PP was independently associated with carotid plaques in old adults with uncontrolled hypertension who have an increased risk of atherosclerosis.

Chronic kidney disease is characterized by "double trouble" higher pulse pressure plus night-time systolic blood pressure and more severe cardiac damage

Background

Hypertension plays a key role in chronic kidney disease (CKD), but CKD itself affects the blood pressure (BP) profile. The aim of this study was to assess the association of BP profile with CKD and the presence of cardiac organ damage.

Methods

We studied 1805 patients, referred to our Hypertension Centre, in whom ABPM, blood tests, and echocardiography were clinically indicated. The glomerular filtration rate was estimated (eGFR) using the MDRD equation and CKD was defined as eGFR<60 mL/min/1.73 m². Cardiac organ damage was evaluated by echocardiography.

Results

Among patients with CKD there were higher systolic blood pressure (SBP) during the night-time, greater prevalence of non-dippers (OR: 1.8) and increased pulse pressure (PP) during 24-hour period, daytime and night-time (all p<0.001). Patients with CKD had a greater LVM/h^2.7 index, and a higher prevalence of left ventricular hypertrophy and diastolic dysfunction (all p<0.001). Nocturnal SBP and PP correlated more strongly with cardiac organ damage (p<0.001). Patients with CKD had a greater Treatment Intensity Score (p<0.001) in the absence of a significantly greater BP control.

Conclusions

CKD patients have an altered night-time pressure profile and higher PP that translate into a more severe cardiac organ damage. In spite of a greater intensity of treatment in most patients with CKD, BP control was similar to patients without CKD. Our findings indicate the need of a better antihypertensive therapy in CKD, better selected drugs, dosages and posology to provide optimal coverage of 24 hours and night-time BP.

Nocturia, Nocturnal Activity, and Nondipping

Patients with chronic kidney disease have less than expected decline in blood pressure during sleep (nondipping) and commonly experience the vexing symptom of nocturia. To better understand the relationship among nocturia, nighttime physical activity, and nondipping, we studied 98 patients with chronic kidney disease on 2 occasions, 1 month apart, with 24-hour ambulatory blood pressure monitoring and simultaneous activity monitoring with wrist actigraphy. Patients with nocturia had greater actigraphically recorded nighttime physical activity compared to those with no nocturia. The drop in activity from wake to sleep was reduced to a similar extent whether the patients had nocturia once or twice, but patients who had nocturia ≥3 times had the least reduction from wake to sleep activity ( P <0.001 versus those with less degrees of nocturia). Those with nocturia had a lesser drop in systolic ambulatory blood pressure during sleep compared with those without nocturia. The average fall in sleep systolic blood pressure was 9.8 mm Hg (95% CI: 8.0 to 11.6 mm Hg) in those without nocturia compared with 3.4 mm Hg (95% CI: 2.7 to 4.1 mm Hg) in those with any severity of nocturia ( P <0.001 for difference). Nondipping in patients with nocturia was mediated by nighttime physical activity. These differences were independent of estimated glomerular filtration rate, albuminuria, or use of diuretics. Thus, nocturia, which may reflect impaired renal tubular function, is associated with nondipping in patients with chronic kidney disease and appears to be mediated by increased nocturnal activity. Whether nocturia itself or the resulting nondipping associated with nocturia is of prognostic importance for cardiorenal events in patients with chronic kidney disease should be tested in future studies.

Dry-weight reduction in hypertensive hemodialysis patients (DRIP): a randomized, controlled trial

Volume excess is thought to be important in the pathogenesis of hypertension among hemodialysis patients. To determine whether additional volume reduction will result in improvement in blood pressure (BP) among hypertensive patients on hemodialysis and to evaluate the time course of this response, we randomly assigned long-term hypertensive hemodialysis patients to ultrafiltration or control groups. The additional ultrafiltration group (n=100) had the dry weight probed without increasing time or duration of dialysis, whereas the control group (n=50) only had physician visits. The primary outcome was change in systolic interdialytic ambulatory BP. Postdialysis weight was reduced by 0.9 kg at 4 weeks and resulted in -6.9 mm Hg (95% CI: -12.4 to -1.3 mm Hg; P=0.016) change in systolic BP and -3.1 mm Hg (95% CI: -6.2 to -0.02 mm Hg; P=0.048) change in diastolic BP. At 8 weeks, dry weight was reduced 1 kg, systolic BP changed -6.6 mm Hg (95% CI: -12.2 to -1.0 mm Hg; P=0.021), and diastolic BP changed -3.3 mm Hg (95% CI: -6.4 to -0.2 mm Hg; P=0.037) from baseline. The Mantel-Hanzel combined odds ratio for systolic BP reduction of > or =10 mm Hg was 2.24 (95% CI: 1.32 to 3.81; P=0.003). There was no deterioration seen in any domain of the kidney disease quality of life health survey despite an increase in intradialytic signs and symptoms of hypotension. The reduction of dry weight is a simple, efficacious, and well-tolerated maneuver to improve BP control in hypertensive hemodialysis patients. Long-term control of BP will depend on continued assessment and maintenance of dry weight.

Physical activity and hemodynamic reactivity in chronic kidney disease

BACKGROUND AND OBJECTIVES

Patients with chronic kidney disease (CKD) have an elevated cardiovascular risk. This study was designed to understand better the presence and strength of the relationship between physical activity and BP and to explore determinants of hemodynamic reactivity.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Twenty-four patients with CKD (mean age 69.5 yr; 3.1 antihypertensive drugs; estimated GFR 47 ml/min per 1.73 m(2), albumin/creatinine ratio 403 mg/g) were studied on three occasions during a 6-wk period with 24-h ambulatory BP monitoring and simultaneous activity monitoring with wrist actigraphy.

RESULTS

Nondippers were found have a greater level of sleep activity compared with dippers, although the awake activity level was similar (7.06 versus 6.73) between groups (P = 0.042 for interaction). In 3587 BP activity pairs, hemodynamic reactivity was variable between individuals (systolic BP reactivity 1.06 [SD 10.50]; diastolic BP reactivity 0.89 [SD 7.80] heart rate reactivity 1.18 [SD 11.00]); those who were more sedentary had a greater increment in systolic BP compared with those who were less sedentary. Antihypertensive drugs blunted hemodynamic reactivity. Hemodynamic reactivity was greatest between 12 a.m. and 8 a.m., making this a vulnerable period for cardiovascular events.

CONCLUSIONS

Greater hemodynamic reactivity in sedentary people with CKD offers a possible and thus far unrecognized mechanism of cardiovascular damage. Besides reducing BP, antihypertensive drugs reduce hemodynamic reactivity, which offers another plausible mechanism of cardiovascular protection with their use.

Blood pressure abnormalities in children with chronic kidney disease

OBJECTIVES

Disturbances of blood pressure (BP) rhythms have been demonstrated in patients with various degrees of renal impairment. The purpose of this study was to determine the prevalence of BP abnormalities in children with chronic kidney disease (CKD) and evaluate possible factors associated with nocturnal BP abnormalities.

METHODS

42 children between 2 and 19 years of age with CKD stages 2-5 completed 24-h ambulatory BP monitoring.

RESULTS

The percentage of patients with daytime hypertension was less than 10% but rates were higher at nighttime where 14% had systolic and 24% diastolic hypertension. A similar percentage of patients had a BP load >50%. BP abnormalities that were not evident in clinic BP readings were identified in 49% of the participants. The nocturnal BP dipping percentage tended to decrease as the estimated glomerular filtration rate decreased. Proteinuria was significantly associated with nocturnal BP nondipping.

CONCLUSION

24-h ambulatory BP monitoring may provide additional insight into hypertension in pediatric patients as early as CKD stage 2. Several BP abnormalities were identified that were not evident in casual BP measurements including nocturnal hypertension, elevated BP load, and nocturnal BP nondipping.

Antihypertensive agents and arterial stiffness: relevance to reducing cardiovascular risk in the chronic kidney disease patient

PURPOSE OF REVIEW

Arterial stiffness is a sign of diffuse adventitial macrovascular disease. The purpose of the present review is to discuss, in patients with chronic kidney disease, the pathophysiology of increased arterial stiffness, the role of antihypertensive therapy on reduction of arterial stiffness, and the clinical ways by which the prognostication of cardiovascular disease in patients with chronic kidney disease can be refined using arterial stiffness monitoring.

RECENT FINDINGS

Arterial stiffness is increased with increasing prevalence of traditional cardiovascular risk factors. In patients with chronic kidney disease some unique factors further increase the risk of arterial stiffness, and include volume overload, activation of the renin-angiotensin system, anemia, and dysregulated mineral metabolism. Arterial stiffness is increased even in patients with early-stage chronic kidney disease. Blood pressure reduction when accompanied by a reduction in arterial stiffness is associated with improved prognosis. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers can preferentially improve arterial stiffness, which may be an additional mechanism of cardiovascular protection with these agents.

SUMMARY

The impact of improvement in arterial stiffness with antihypertensive agents on cardiovascular outcomes needs well designed clinical trials.

Increased blood pressure in adult offspring of families with Balkan endemic nephropathy: a prospective study

BACKGROUND

Previous studies have linked smaller kidney dimensions to increased blood pressure. However, patients with Balkan Endemic Nephropathy (BEN), whose kidneys shrink during the course of the disease, do not manifest increased blood pressure. The authors evaluated the relationship between kidney cortex width, kidney length, and blood pressure in the offspring of BEN patients and controls.

METHODS

102 offspring of BEN patients and 99 control offspring of non-BEN hospital patients in the Vratza District, Bulgaria, were enrolled in a prospective study and examined twice (2003/04 and 2004/05). Kidney dimensions were determined using ultrasound, blood pressure was measured, and medical information was collected. The parental disease of BEN was categorized into three groups: mother, father, or both parents. Repeated measurements were analyzed with mixed regression models.

RESULTS

In all participants, a decrease in minimal kidney cortex width of 1 mm was related to an increase in systolic blood pressure of 1.4 mm Hg (p = 0.005). There was no association between kidney length and blood pressure. A maternal history of BEN was associated with an increase in systolic blood pressure of 6.7 mm Hg (p = 0.03); paternal BEN, +3.2 mm Hg (p = 0.35); or both parents affected, +9.9 mm Hg (p = 0.002). There was a similar relation of kidney cortex width and parental history of BEN with pulse pressure; however, no association with diastolic blood pressure was found.

CONCLUSION

In BEN and control offspring, a smaller kidney cortex width predisposed to higher blood pressure. Unexpectedly, a maternal history of BEN was associated with average increased systolic blood pressure in offspring.

Correlates of systolic hypertension in patients with chronic kidney disease

Hypertension in patients with chronic kidney disease (CKD) is predominantly systolic. The contribution of risk factors for hypertension to the overall systolic blood pressure (BP) is unknown. To study the relationship between risk factors for hypertension and systolic BP in patients with CKD, 232 veterans (mean age 67 years; 96% men; 20% black; 39% with diabetes mellitus; estimated glomerular filtration rate [GFR] 48 mL/min per 1.73 m2) had clinic (routine and standardized measurements) and out-of-clinic (home and 24-hour ambulatory) BPs recorded. In multivariate analysis, using 17 risk factors, the log of the urine protein/creatinine ratio was the strongest predictor of systolic BP regardless of the BP measurement technique. The strength of the relationship between proteinuria and systolic BP was in the order ambulatory > home > standardized clinic > routine clinic BP measurement. Other independent predictors were age, race, and number of antihypertensive drugs used, and the model fit was better for out-of-clinic than clinic BP recordings. Estimated GFR was not an independent predictor of systolic BP by any technique. Nocturnal dipping was associated with higher estimated GFR, higher serum albumin, younger age, and less proteinuria. Proteinuria is the most important correlate of systolic BP in older men, the strongest relationship of which was with ambulatory and home systolic BP. Out-of-clinic BP recordings correlate better with target organ damage, as measured by proteinuria, and may be of greater clinical value than clinic BP recordings in predicting hypertension-related outcomes such as end-stage renal disease and death.