Office blood pressure measurements overestimate blood pressure control in renal transplant patients

Telemedicine for Kidney Transplant Recipients: Current State, Advantages, and Barriers

Telemedicine is defined as the use of electronic information and communication technologies to provide and support healthcare at a distance. In kidney transplantation, telemedicine is limited but is expected to grow markedly in the coming y. Current experience shows that it is possible to provide transplant care at a distance, with benefits for patients like reduced travel time and costs, better adherence to medication and appointment visits, more self-sufficiency, and more reliable blood pressure values. However, multiple barriers in different areas need to be overcome for successful implementation, such as recipients' preferences, willingness, skills, and digital literacy. Moreover, in many countries, limited digital infrastructure, legislation, local policy, costs, and reimbursement issues could be barriers to the implementation of telemedicine. Finally, telemedicine changes the way transplant professionals provide care, and this transition needs time, training, willingness, and acceptance. This review discusses the current state and benefits of telemedicine in kidney transplantation, with the aforementioned barriers, and provides an overview of future directions on telemedicine in kidney transplantation.

Differences of blood pressure measured at clinic versus at home in the morning and in the evening in Europe and Asia: A systematic review and meta-analysis

Numerous studies have indicated that there might be great differences among different populations in Europe and Asia in terms of home morning and evening blood pressure (BP). Thus, the authors performed a systematic review to determine the quantitative differences of BP measured at clinic versus at home in the morning and in the evening in Europe and Asia. PubMed, Embase, and Scopus databases were searched up to October 2021. Studies that compared clinic BP with home morning and (or) home evening BP in European and Asian populations were included. A random effect model was applied to pool the differences between clinic BP and home morning/evening BP. Thirty‐five studies, for a total of 49 432 patients, were included in this meta‐analysis. Mean clinic systolic blood pressure (SBP) values were significantly higher than home morning SBP values by 3.79 mmHg (95% CI, 2.77–4.80). The differences were much larger in Europe [(6.53 mmHg (95% CI, 4.10–8.97)] than in Asia [(2.70 mmHg (95% CI, 1.74–3.66)], and the region was a significant predictor for the differences. Mean clinic SBP values were also significantly higher than home evening SBP values by 6.59 mmHg (95% CI, 4.98–8.21). The differences were much smaller in Europe [5.85 mmHg (95% CI, 3.24–8.45)] than in Asia [7.13 mmHg (95% CI, 4.92–9.35)], while age and clinic SBP might contribute to it. Our findings showed that the difference between clinic and home morning SBP was much larger in European than Asian populations, whereas the difference between clinic and home evening SBP was the opposite. The differing characteristics of the region, ethnic, age, and clinic BP might explain the diversities.

Assessment of hypertension in kidney transplantation by ambulatory blood pressure monitoring: a systematic review and meta-analysis

Background

Hypertension (HTN) is common following renal transplantation and it is associated with adverse effects on cardiovascular (CV) and graft health. Ambulatory blood pressure monitoring (ABPM) is the preferred method to characterize blood pressure (BP) status, since HTN misclassification by office BP (OBP) is quite common in this population. We performed a systematic review and meta-analysis aimed at determining the clinical utility of 24-h ABPM and its potential implications for the management of HTN in this population.

Methods

Ovid-MEDLINE and PubMed databases were searched for interventional or observational studies enrolling adult kidney transplant recipients (KTRs) undergoing 24-h ABP readings compared with OBP or home BP. The main outcome was the proportion of KTRs diagnosed with HTN by ABPM, home or OBP recordings. Additionally, day-night BP variability and dipper/non-dipper status were assessed.

Results

Forty-two eligible studies (4115 participants) were reviewed. A cumulative analysis including 27 studies (3481 participants) revealed a prevalence of uncontrolled HTN detected by ABPM of 56% [95% confidence interval (CI) 46-65%]. The pooled prevalence of uncontrolled HTN according to OBP was 47% (95% CI 36-58%) in 25 studies (3261 participants). Very few studies reported on home BP recordings. The average concordance rate between OBP and ABPM measurements in classifying patients as controlled or uncontrolled hypertensive was 66% (95% CI 59-73%). ABPM revealed HTN phenotypes among KTRs. Two pooled analyses of 11 and 10 studies, respectively, revealed an average prevalence of 26% (95% CI 19-33%) for masked HTN (MHT) and 10% (95% CI 6-17%) for white-coat HTN (WCH). The proportion of non-dippers was variable across the 28 studies that analysed dipping status, with an average prevalence of 54% (95% CI 45-63%).

Conclusions

In our systematic review, comparison of OBP versus ABP measurements disclosed a high proportion of MHT, uncontrolled HTN and, to a lesser extent, WCH in KTRs. These results suggest that HTN is not adequately diagnosed and controlled by OBP recordings in this population. Furthermore, the high prevalence of non-dippers confirmed that circadian rhythm is commonly disturbed in KTRs.

Masked Hypertension and Obesity in Renal Transplant Recipients

The diagnosis of arterial hypertension has traditionally been based on measurements of blood pressure (BP) in the clinic. However, home or ambulatory BP monitoring (ABPM) is reported to correlate better with target organ damage than clinic BP readings. The other potential advantage of out-of-clinic BP measurement is the detection of both white-coat hypertension (WCHT) and masked hypertension (MHT). Studies have suggested that MHT have an increased risk of cardiovascular disease (CVD). We aimed to investigate the prevalence of MHT and to evaluate risk factors by ABPM in our renal transplant recipients. One hundred twenty-ninety patients who were followed up in our nephrology clinic were included in the study. The prevalence of MHT was 17%. In logistic regression analysis, we investigated factors associated with MHT. In a model with age, sex, smoking, presence of Diabetes mellitus (DM) and blood glucose, estimated glomerular filtration rate (eGFR), donor type, body mass index, waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR), we found that WHR (r: 18.61, P: .007) and smoking (r: 2.79, P: .011) were related with MHT. MHT was related to target organ damage and cardiovascular disease. The diagnosis and treatment of MHT are important. These findings suggesting that patients with high WC and smokers should be investigated with ABPM to diagnose masked hypertension. This approach may reduce adverse cardiovascular outcomes after transplantation.

The Short-Term Impact of Dietary Counseling on Sodium Intake and Blood Pressure in Renal Allograft Recipients

Background:

Sodium retention causes posttransplant hypertension, and sodium restriction is recommended in kidney allograft recipients. However, there have been few studies on the impact of dietary counseling on sodium intake and blood pressure (BP) in this population.

Objective:

To determine the effect of dietary counseling on sodium intake and consequent BP control in kidney allograft recipients.

Design, Setting, and Participants:

A prospective single-arm study to determine the effect of dietary counseling on sodium intake. Enrolled were renal allograft recipients with sodium intake >100 mEq/d, BP >130/80, antihypertensive use, or body mass index >25 kg/m2. Of 53 renal transplant recipients who met the criteria, 48 participated in the present study. Sodium intake was estimated based on 24-hour urinary sodium excretion before and after 3 sessions of dietary counseling by a board-certified dietitian.

Results:

Sodium intake was significantly decreased after dietary counseling (158.7 vs 129.6 mEq/d; P = .005). Systolic BP was significantly decreased from 124 mm Hg (interquartile range: 122-134) before counseling to 121 mm Hg (interquartile range: 117-128) after counseling ( P < .001). The number of patients with systolic BP >130 mm Hg was decreased by 30% (n = 19-13; P = .07). Among 34 patients on antihypertensive medications, 8 (23.5%) ceased or reduced their drugs due to improvement in BP, whereas 2 increased or changed the drugs due to poor control of BP.

Conclusion:

Dietary counseling showed a short-term efficacy of reducing sodium intake and clinically relevant BP improvement in renal allograft recipients.

Ambulatory Blood Pressure Monitoring and Echocardiographic Findings in Renal Transplant Recipients

Hypertension is common in renal transplant recipients (RTRs). Ambulatory blood pressure (BP) monitoring (ABPM) is important in diagnosing hypertension and diurnal BP variation. The authors set out to compare office BP and ABPM measurements to determine diurnal pattern and to evaluate echocardiographic findings in RTRs. ABPM and office BP measurements were compared in 87 RTRs. Echocardiographic evaluation was performed for each patient. The correlations between office and 24-hour ABPM were 0.275 for mean systolic BP (P=.011) and 0.260 for mean diastolic BP (P=.017). Only 36.8% had concordant hypertension between office BP and ABPM, with a masked hypertension rate of 16.1% and white-coat effect rate of 24.1%. Circadian BP patterns showed a higher proportion of nondippers (67.8%). Left ventricular mass index was increased in 21.8% of all recipients. There was a significant but weak correlation between office BP and ABPM.

Achieving blood pressure control among renal transplant recipients by integrating electronic health technology and clinical pharmacy services

PURPOSE

The implementation and outcomes of a program combining electronic home blood pressure monitoring (HBPM) and pharmacist-provided medication therapy management (MTM) services in a renal transplantation clinic are described.

SUMMARY

Patients enrolled in the program were provided with a computer-enabled blood pressure monitor. A dedicated renal transplantation pharmacist was integrated into the renal transplantation team under a collaborative care practice agreement. The collaborative care agreement allowed the pharmacist to authorize medication additions, deletions, and dosage changes. Comprehensive disease and blood pressure education was provided by a clinical pharmacist. In the pretransplantation setting, the pharmacist interviewed the renal transplant candidate and documents allergies, verified the patient's medication profile, and identified and assessed barriers to medication adherence. A total of 50 renal transplant recipients with at least one recorded home blood pressure reading and at least one year of follow-up were included in our analysis. A significant reduction in mean systolic and diastolic blood pressure values were observed at 30, 90, 180, and 360 days after enrollment in the program (p < 0.05). Pharmacist interventions were documented for 37 patients. Medication-related problems accounted for 46% of these interventions and included dosage modifications, regimen changes, and mitigation of barriers to medication access and adherence.

CONCLUSION

Implementation of electronic HBPM and pharmacist-provided MTM services implemented in a renal transplant clinic was associated with sustained improvements in blood pressure control. Incorporation of a pharmacist in the renal transplant clinic resulted in the detection and resolution of medication-related problems.

Hypertension, living kidney donors, and transplantation: where are we today?

Hypertension is a prevalent problem in kidney transplant recipients that is known to be a "traditional" risk factor for atherosclerotic cardiovascular disease leading to premature allograft failure and death. Donor, peritransplant, and recipient factors affect hypertension risk. Blood pressure control after transplantation is inversely associated with glomerular filtration rate (GFR). Calcineurin inhibitors, the most commonly used class of immunosuppressives, cause endothelial dysfunction, increase vascular tone, and sodium retention via the renin-angiotensin-aldosterone system resulting in systemic hypertension. Steroid withdrawal seems to have little impact on blood pressure control. Newer agents like belatacept appear to be associated with less hypertension. Transplant renal artery stenosis is an important, potentially treatable cause of hypertension. Dihydropyridine calcium channel blockers mitigate calcineurin inhibitor nephrotoxicity and may be associated with improved estimated GFR. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are not recommended in the first 3 to 6 months given their effects on reduced estimated GFR, anemia, and hyperkalemia. The use of ß-blockers may be associated with improved patient survival, even for patients without cardiovascular disease. Living donation may increase blood pressure by 5 mm Hg or more. Some transplant centers accept Caucasian living donors with well-controlled hypertension on a single agent if they agree to close follow-up.

Ambulatory vs office blood pressure monitoring in renal transplant recipients

Hypertension is common following renal transplantation and has adverse effects on cardiovascular and graft health. Ambulatory blood pressure monitoring (ABPM) is better at overall blood pressure (BP) assessment and is necessary to diagnose nocturnal hypertension, which is also implicated in poor outcomes. The authors performed a retrospective analysis of 98 renal transplant recipients (RTRs) and compared office BP and ambulatory BP recordings. ABPM revealed discordance between office BP and ambulatory BP in 61% of patients, with 3% caused by white-coat and 58% caused by masked hypertension (of which 33% were caused by isolated nocturnal hypertension). Overall, mean systolic BP was 3.6 mm Hg (0.5-6.5) and diastolic BP was 7.5 mm Hg (5.7-9.3) higher via ambulatory BP than office BP. This was independent of estimated glomerular filtration rate, proteinuria, transplant time/type, and comorbidities. A total of 42% of patients had their management changed after results from ABPM. ABPM should be routinely offered as part of hypertension management in RTRs.

Comparison of office, home, and ambulatory blood pressure in heart transplant recipients

BACKGROUND

The purpose of this study was to prospectively evaluate the relationship between office, home, and ambulatory blood pressure (BP) in heart transplant recipients.

METHODS AND RESULTS

The study enrolled 30 adults ≥ 6 months after heart transplantation. Morning seated office BP was measured with the use of an automatic device at 3 outpatient visits. Seated home BP was measured in the morning and evening for 5 consecutive days. Ambulatory BP was measured over 24 hours with the use of a Spacelabs monitor. The strongest correlation was observed between home and 24-hour ambulatory BP (r = 0.79 systolic; r = 0.72 diastolic). Office and home systolic BPs were significantly lower than daytime ambulatory BP (office, -3.7 mm Hg, P = .009; home, -2.6 mm Hg, P = .05). Ambulatory monitoring identified more participants with BP above hypertensive limits than did office or home measurements (63%, 50%, and 13%, respectively; P = .003). Ambulatory monitoring also revealed high BP loads, abnormal nocturnal BP patterns (eg, 30% nondippers), and a high percentage of masked hypertension (37% home, 50% ambulatory).

CONCLUSIONS

Office and home BP monitoring are acceptable but may underestimate BP burden in heart transplant recipients. Additional studies are needed to determine which BP method is superior for the management of hypertension and associated outcomes after heart transplantation.

Hypertension after kidney transplantation: a pathophysiologic approach

Post-transplant hypertension is associated with decreased graft and patient survival and cardiovascular morbidity. Unfortunately, post-transplant hypertension is often poorly controlled. Important risk factors include immunosuppressive medications, complications of the transplant surgery, delayed graft function, rejection, and donor and recipient risk factors. The effects of immunosuppressive medications are multifactorial including increased vascular and sympathetic tone and salt and fluid retention. The immunosuppressive agents most commonly associated with hypertension are glucocorticoids and calcineurin inhibitors. Drug therapy for hypertension should be based on the comorbidities and pathophysiology. Evidence-based approaches to defining and treating hypertension in renal transplant recipients are predominantly extrapolated from large-scale studies performed in the general population. Thus, there continues to be a need for larger studies examining the pathophysiology, diagnosis and treatment of hypertension in renal transplant recipients.

Masked hypertension in renal transplant recipients

PURPOSE

Arterial hypertension is a risk factor affecting graft function in renal transplant recipients (RTRs). In pediatric RTRs, high prevalence of masked and nocturnal hypertension was reported. Most of the RTRs had a history of hypertension and some of them were normotensive at outpatient visits whereas home blood pressure (BP) levels were higher. Masked hypertension (MHT) is defined as a normal office BP but an elevated ambulatory BP. Previous reports have demonstrated the detrimental role of MHT in clinical outcomes in hypertensive patients. However, the true prevalence of MHT in RTRs is yet to be defined.

METHODS

A total of 113 RTRs (mean age 44 ± 16 years, 72 males, 41 females) with normal office BP (< 140/90 mmHg) were enrolled to the study from the outpatient renal transplantation clinic. Ambulatory BP monitoring (ABPM) was performed in all participants for a 24-h period. Average daytime BP values above 135 mmHg systolic and 85 mmHg diastolic were defined as MHT.

RESULTS

The prevalence of MHT in our cohort was 39% (n = 45). Fasting glucose and C-reactive protein levels were higher in patients with MHT compared with normal BP group (p = 0.02 and p = 0.04, respectively). RTRs with deceased donor type had higher prevalence of MHT than RTRs with living donor (40% vs 19%, p = 0.003). In multivariate analysis, deceased donor type could predict the MHT independent of age, gender, office systolic BP level, diabetes mellitus, serum creatinine, C-reactive protein, and glucose levels (OR = 3.62, 95% CI 1.16-11.31, p = 0.03).

CONCLUSION

We demonstrated an increased prevalence of MHT in a typical renal transplant cohort. In addition, transplantation from a deceased donor may be a predictor of MHT. The prevalence of MHT may help to explain high rate of cardiovascular events in RTRs. Therefore, routine application of ABPM in RTRs may be plausible, particularly in RTRs with deceased donor type.

Hypertension: The Neglected Complication of Transplantation

Arterial hypertension and transplantation are closely linked, and its association may promote impaired graft and overall survival. Since the introduction of calcineurin inhibitors, it is observed in 50–80% of transplanted patients. However, many pathophysiological mechanisms are involved in its genesis. In this review, we intend to provide an updated overview of these mechanisms, dealing with the causes common to all kinds of transplantation and emphasizing special cases with distinct features, and to give a perspective on the pharmacological approach, in order to help clinicians in the management of this frequent complication.

Home and office blood pressure monitoring in renal transplant recipients

Background. Arterial hypertension in renal transplant recipients (RTR) is associated with increased morbid mortality. In the general population, home blood pressure monitoring (HBPM) was found to be superior to office blood pressure (OBP) in identifying true hypertensive patients. The aim of this study was to investigate HBPM for the assessment of blood pressure profile in RTR. Methodology and Principal Findings. We included prospectively 87 stable RTR. Sitting OBP was measured during the outpatient clinic. HBPM was performed by measuring BP every morning and night for 4 days. The accepted limits for the OBP and HBPM, were respectively, 140/90 mmHg and 135/85 mmHg. Patients were classified as “normotensive,” “uncontrolled,” “white-coat hypertensive” and “masked hypertensive”, (OBP below the limit and HBPM above). During the study, 81 patients (55 males, age 48.5 ± 14 years) were available for analysis. The mean OBP and HBP were 138/83 ± 14/10 mmHg and 133/79 ± 14/8 mmHg; 29% of patients were uncontrolled, 28% normotensive, 21% white coat, and 21% masked hypertensive. Age, glycemia, and number of antihypertensive drugs were associated with hypertension. Conclusion and Significance. In RTR, HBPM is well accepted and better define BP profile since there is 42% discrepancy between OBPM and HBPM. Whether this discrepancy is associated with worst outcome in the long term remains to be demonstrated.

Contribution of anemia and hypertension to left ventricular hypertrophy during the initial 2 years after renal transplantation

BACKGROUND

Cardiovascular disease is the main cause of mortality after renal transplantation. Left ventricular hypertrophy (LVH) is considered to be an independent predictor of cardiovascular events. The main risk factors for LVH after renal transplantation are anemia and hypertension. In hypertensive and renal transplant patients, ambulatory blood pressure monitoring (ABPM) has been demonstrated to be more closely related to LVH than office blood pressure. The aim of this study has to evaluate LVH after renal transplantation, particularly its association with measures derived from ABPM and cardiovascular risk factors.

PATIENTS AND METHODS

Between March 2005 and October 2006, we recruited 101 consecutive kidney transplant patients to calculate left ventricular mass index (LVMI) by echocardiography at 3, 12, and 24 months. Hypertension was evaluated by office blood pressure measurements at 3, 12, and 24 months and also by ABPM at 3 months. Clinical and laboratory data were recorded during the study.

RESULTS

From 3 to 24 months LVMI was reduced from 129 ± 29 g/m(2) to 121 ± 34 g/m(2) (P = .0089). Multivariate stepwise regression analysis showed independent predictors of LVMI at 3 months to be hemoglobin at 1 month, day systolic blood pressure (SBP) derived from ABPM and donor age (R = .50, P < .001). The independent predictors of LVMI at 12 months were day SBP derived from ABPM, hemoglobin at 1 month, and proteinuria at 12 months (R = .55, P < .001). Office SBP at 12 months, proteinuria at 24 months, patient age and night diastolic blood pressure derived from ABPM at 3 months were independent predictors of LVMI at 24 months (R = .71, P < .001).

CONCLUSION

We observed a significant reduction in LVMI after renal transplantation. The main contributors to LVMI were anemia and elevated blood pressures measured by ABPM.

Ambulatory blood pressure monitoring in renal transplant patients: should it be routinely performed?

INTRODUCTION

Arterial hypertension is common among kidney transplant patients. It increases cardiovascular risk and is a factor for progression of renal failure. Our objective was to perform ambulatory blood pressure monitoring (ABPM) in renal transplant patients with office hypertension.

METHODS

Patients were divided into 2 groups according to their mean ABPM blood pressures with treatment: well-controlled hypertension (blood pressure [BP] <130/85 mmHg), and poorly controlled hypertension (BP>130/85 mmHg). A "nondipper pattern" was defined as a decrease of <10% or an increase, and a "raiser pattern," in which mean blood pressure was greater during the nocturnal than the diurnal period. "White coat effect" was considered when the mean of 3 BP measurements in the clinic was >140/90 mmHg among well-controlled hypertensive patients as documented by ABPM.

RESULTS

ABPM was performed in 53 patients: 25 (47%) "well-controlled hypertensives" and 28 (53%) "poorly controlled hypertensives." Of the latter, 24 (85%) showed a nondipper or raiser pattern with only 4 revealing dipper patterns. We compared well-controlled with poorly controlled hypertensives. The latter cohort were older (54.4±9.3 vs 45.5±13.8 years; P=.009), received grafts from older donors (56.7±15.0 vs 45.8±17 years; P=.02); had worse renal function measured by serum creatinine (1.7±0.5 vs 1.4±0.4 mg/dL, P=.03) or the Modification of Diet in Renal Disease (MDRD)=4 formula (41.8±14.0 vs 55.4±20.5 mL/min/1.73 m2; P=.009), and displayed more proteinuria (0.30±0.33 vs 0.18±0.10 g/d, P=.08). Nondipper or raiser patients showed a higher mean body mass index (27.1 vs 21.7 kg/m2; P=.04). Among 25 well-controlled patients, 11 presented "white coat phenomenon."

CONCLUSION

We observed an important "white coat" effect, a large prevalence of uncontrolled nocturnal hypertension, and a small but important incident of "masked hypertension." Factors related to hypertension control were patient age, donor age, renal function, induction use, and proteinuria.

Hypertension after kidney transplant

Hypertension in kidney transplant recipients is a major "traditional" risk factor for atherosclerotic cardiovascular disease. Importantly, atherosclerotic cardiovascular disease is the leading cause of premature death and a major factor in death-censored graft failure in transplant recipients. The blood pressure achieved after transplant is related inversely to postoperative glomerular filtration rate (GFR), with many patients experiencing a significant improvement in blood pressure control with fewer medications within months of surgery. However, the benefits of improved GFR and fluid status may be affected by the immunosuppression regimen. Immunosuppressive agents affect hypertension through a variety of mechanisms, including catechol- and endothelin-induced vasoconstriction, abrogation of nitric oxide-induced vasodilatation, and sodium retention. Most notable is the role of calcineurin inhibitors in promoting hypertension, cyclosporine more so than tacrolimus. Additionally, the combination of calcineurin- and mammalian target of rapamycin (mTOR)-inhibitor therapy is synergistically nephrotoxic and promotes hypertension, whereas steroid withdrawal and minimization strategies seem to have little or no impact on hypertension. Other important causes of hypertension after transplant, beyond a progressive decrease in GFR, include transplant renal artery stenosis and sequelae of antibody-mediated rejection. Calcium channel blockers may be the most useful medication for mitigating calcineurin inhibitor-induced vasoconstriction, and use of such agents may be associated with improvements in GFR. Use of inhibitors of the renin-angiotensin system, such as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, remains an attractive strategy for many transplant recipients, although some recipients may have significant adverse effects associated with these medications, including decreased GFR, hyperkalemia, and anemia. In conclusion, hypertension control affects both patient and long-term transplant survival, and its best management requires careful analysis of causes and close monitoring of therapies.

Home blood pressure monitoring in the diagnosis and treatment of hypertension: a systematic review

BACKGROUND

It is recognized that for the reliable assessment of blood pressure (BP) and the accurate diagnosis of hypertension, out-of-office BP measurement with ambulatory (ABPM) or home BP monitoring (HBPM) is often required. The clinical usefulness of ABPM is well established. However, despite the wide use of HBPM, only in the last decade convincing evidence on its usefulness has accumulated.

METHODS

Systematic review of the evidence on applying HBPM in the diagnosis and treatment of hypertension (PubMed, Cochrane Library, 1970-2010).

RESULTS

Sixteen studies in untreated and treated subjects assessed the diagnostic ability of HBPM by taking ABPM as reference. Seven randomized studies compared HBPM vs. office measurements or ABPM for treatment adjustment, whereas many studies compared HBPM with office measurements in assessing the antihypertensive drug effects. Several studies with different design investigated the role of HBPM vs. office measurements in improving patients' compliance with treatment and hypertension control rates. The evidence on the cost-effectiveness of HBPM is limited. The studies reviewed consistently showed moderate diagnostic agreement between HBPM and ABPM, and superiority of HBPM compared to office measurements in diagnosing uncontrolled hypertension, assessing antihypertensive drug effects and improving patients' compliance and hypertension control. Preliminary evidence suggests that HBPM has the potential for cost savings.

CONCLUSIONS

There is conclusive evidence that HBPM is useful for the initial diagnosis and the long-term follow-up of treated hypertension. These data are useful for the optimal application of HBPM, which is widely used in clinical practice. More studies on the cost-effectiveness of HBPM are needed.

Regulation of circadian blood pressure: from mice to astronauts

PURPOSE OF REVIEW

Circadian variation is commonly seen in healthy people; aberration in these biological rhythms is an early sign of disease. Impaired circadian variation of blood pressure (BP) has been shown to be associated with greater target organ damage and with an elevated risk of cardiovascular events independent of the BP load. The purpose of this review is to examine the physiology of circadian BP variation and propose a tripartite model that explains the regulation of circadian BP.

RECENT FINDINGS

The time-keeper in mammals resides centrally in the suprachiasmatic nucleus. Apart from this central clock, molecular clocks exist in most peripheral tissues including vascular tissue and the kidney. These molecular clocks regulate sodium balance, sympathetic function and vascular tone. A physiological model is proposed that integrates our understanding of molecular clocks in mice with the circadian BP variation among humans. The master regulator in this proposed model is the sleep-activity cycle. The equivalents of peripheral clocks are endothelial and adrenergic functions. Thus, in the proposed model, the variation in circadian BP is dependent upon three major factors: physical activity, autonomic function, and sodium sensitivity.

SUMMARY

The integrated consideration of physical activity, autonomic function, and sodium sensitivity appears to explain the physiology of circadian BP variation and the pathophysiology of disrupted BP rhythms in various conditions and disease states. Our understanding of molecular clocks in mice may help to explain the provenance of blunted circadian BP variation even among astronauts.

Hypertension in dialysis and kidney transplant patients

For the first time, the Canadian Hypertension Education Program has studied the evidence supporting blood pressure control in people requiring renal replacement therapy for end-stage kidney disease, including those on dialysis and with renal transplants. According to the Canadian Organ Replacement Registry's 2008 annual report, there were an estimated 33,832 people with end-stage renal disease in Canada at the end of 2006, an increase of 69.7% since 1997. Of these, 20,465 were on dialysis and 13,367 were living with a functioning kidney transplant. Thus, it is becoming more likely that primary care practitioners will be helping to care for these complex patients. With the lack of large controlled clinical trials, the consensus recommendation based on interpretation of the existing literature is that blood pressure should be lowered to below 140/90 mmHg in hypertensive patients on renal replacement therapy and to below 130/80 mmHg for renal transplant patients with diabetes or chronic kidney disease.

From treatment to organ damage; a 5-year follow-up study of ambulatory blood pressure in essential hypertension. Diversity between development of left ventricular hypertrophy and urinary albumin excretion

This study aimed to assess blood pressure (BP) profile, BP control, left ventricular hypertrophy (LVH) and albumin/creatinine ratio (ACR) in urine after 5 years of antihypertensive treatment in subjects with newly diagnosed essential hypertension. Fifty-four subjects were included and prescribed calcium-channel blocker in monotherapy during an 8-week period, and later 46 subjects (34 men, 12 women, 53.1+/-8.6 years) attended a 5-year follow-up visit at the hypertension clinic. They underwent 24-h ambulatory BP monitoring (ABPM), ECG and ACR at baseline and after 5 years. Echocardiography performed after 5 years revealed LVH in 54% of the subjects, while there was no change in Cornell product, an ECG criterion for LVH. BP control assessed by office BP was 33%, and only 20% using 24-h ABP. Night-time fall in BP was significantly attenuated from 13.2+/-5.9% to 10.7+/-6.0%, p = 0.01 for systolic BP and from 13.3+/-6.9% to 9.8+/-6.8%, p = 0.004 for diastolic BP. The number of dippers decreased after 5 years, but this did not reach statistical significance. In contrast to the lack of change in Cornell product, there was a significant decrease in ACR, and 93% of the subjects had ACR<1.5 mg/mmol after 5 years compared with 57% at baseline (p<0.001). Thus, ABPM should be encouraged in the follow-up of all hypertensive subjects as it reveals better inadequate BP control than office BP and gives information about night-time fall, as this may explain the high prevalence of LVH. The diversity in development of LVH and ACR during antihypertensive treatment needs to be verified.

Hypertension After Renal Transplant

Hypertension is common after renal transplant and is associated with adverse graft and patient outcomes. A thorough understanding of the unique factors that operate in renal transplant recipients is essential for the proper evaluation and management of this disorder. In this review, the authors outline the pathogenesis, diagnostic workup, and treatment of hypertension after renal transplant.