Dynamics of the circadian blood pressure profiles after renal transplantation

Ambulatory blood pressure trajectories and blood pressure variability in kidney transplant recipients: a comparative study against haemodialysis patients

Background

Hypertension is the most prevalent cardiovascular risk factor in kidney transplant recipients (KTRs). Preliminary data suggest similar ambulatory blood pressure (BP) levels in KTRs and haemodialysis (HD) patients. This is the first study comparing the full ambulatory BP profile and short-term BP variability (BPV) in KTRs versus HD patients.

Methods

A total of 204 KTRs were matched (2:1 ratio) with 102 HD patients for age and gender. BP levels, BP trajectories and BPV indices over a 24-h ambulatory BP monitoring (ABPM) in KTRs were compared against both the first and second 24-h periods of a standard 48-h ABPM in HD patients. To evaluate the effect of renal replacement treatment and time on ambulatory BP levels, a two-way ANOVA for repeated measurements was performed.

Results

KTRs had significantly lower systolic blood pressure (SBP) and pulse-pressure (PP) levels compared with HD patients during all periods studied (24-h SBP: KTR: 126.5 ± 12.1 mmHg; HD first 24 h: 132.0 ± 18.1 mmHg; P = 0.006; second 24 h: 134.3 ± 17.7 mmHg; P < 0.001); no significant differences were noted for diastolic blood pressure levels with the exception of the second nighttime. Repeated measurements ANOVA showed a significant effect of renal replacement therapy modality and time on ambulatory SBP levels during all periods studied, and a significant interaction between them; the greatest between-group difference in BP (KTRs-HD in mmHg) was observed at the end of the second 24 h [-13.9 mmHg (95% confidence interval -21.5 to -6.2); P < 0.001]. Ambulatory systolic and diastolic BPV indices were significantly lower in KTRs than in HD patients during all periods studied (24-h SBP average real variability: KTRs: 9.6 ± 2.3 mmHg; HD first 24 h: 10.3 ± 3.0 mmHg; P = 0.032; second 24 h: 11.5 ± 3.0 mmHg; P < 0.001). No differences were noted in dipping pattern between the two groups.

Conclusions

SBP and PP levels and trajectories, and BPV were significantly lower in KTRs compared with age- and gender-matched HD patients during all periods studied. These findings suggest a more favourable ambulatory BP profile in KTRs, in contrast to previous observations.

Circadian rhythms and renal pathophysiology

The reality of life in modern times is that our internal circadian rhythms are often out of alignment with the light/dark cycle of the external environment. This is known as circadian disruption, and a wealth of epidemiological evidence shows that it is associated with an increased risk for cardiovascular disease. Cardiovascular disease remains the top cause of death in the United States, and kidney disease in particular is a tremendous public health burden that contributes to cardiovascular deaths. There is an urgent need for new treatments for kidney disease; circadian rhythm-based therapies may be of potential benefit. The goal of this Review is to summarize the existing data that demonstrate a connection between circadian rhythm disruption and renal impairment in humans. Specifically, we will focus on chronic kidney disease, lupus nephritis, hypertension, and aging. Importantly, the relationship between circadian dysfunction and pathophysiology is thought to be bidirectional. Here we discuss the gaps in our knowledge of the mechanisms underlying circadian dysfunction in diseases of the kidney. Finally, we provide a brief overview of potential circadian rhythm-based interventions that could provide benefit in renal disease.

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.

Unattended automated office blood pressure in living donor kidney transplant recipients

PURPOSE

Hypertension is common in kidney transplant recipients (KTRs). For the evaluation of blood pressure (BP), 24-h ambulatory BP measurements (ABPM) are considered superior to usual office measurements but are also resource demanding and troublesome to many patients. We therefore evaluated the use of unattended automated office BP (AOBP) during the first year following living donor kidney transplantation and compared AOBP with ABPM as obtained 12 months after transplantation.

MATERIALS AND METHODS

Data were retrieved from a cohort of 57 KTRs (mean age 45 ± 14 years, 75% males) who all received kidneys from living donors and had a good graft function (estimated glomerular filtration rate (eGFR) 52 ± 16 ml/min/1.73 m² at 12 months). Unattended AOBP was measured at each visit to the outpatient clinic using the BpTru® device, while ABPM was obtained by Spacelabs® equipment before and 12 months after transplantation.

RESULTS

AOBP remained stable from month 2 (130.2 ± 10.8/82.2 ± 7.8 mmHg) to month 12 (129.0 ± 12.8/83.1 ± 9.6 mmHg) post-transplantation. At 12 months follow-up, ambulatory daytime systolic BP was slightly higher than AOBP (132.7 ± 10.7 vs. 129.4 ± 12.2 mmHg, p = 0.04), while diastolic BP was similar (82.7 ± 7.7 vs. 82.0 ± 10.2 mmHg). Using Bland-Altman plots, 95% limits of agreements were -17.9 to 24.5 mmHg for systolic and -16.5 to 15.1 mmHg for diastolic BP. When considering a target BP of ≤130/<80 mmHg, 62% had sustained hypertension, 9% white coat hypertension and 11% masked hypertension. Using multiple linear regression analysis, only urine albumin-creatinine ratio tended to predict a higher systolic AOBP (p = 0.07).

CONCLUSION

In a cohort of stable living donor KTRs, mean values of unattended AOBP using BpTru® are comparable to daytime ABPM with a misclassification rate of approximately 20%.

Relationship between renal function and blood pressure dipping status in renal transplant recipients: a longitudinal study

Background

Hypertension (HT) is associated with adverse outcomes in kidney transplant (KTX) recipients. Blunting of physiological decrease in nighttime compared to daytime blood pressure (non-dipping status) is frequent in this setting. However, weather non-dipping is independently associated with renal function decline in KTX patients is unknown.

Methods

We retrospectively screened KTX outpatients attending for a routine ambulatory blood pressure monitoring (ABPM) (T1) at a single tertiary hospital. Patients had two successive follow-up visits, 1 (T2) and 2 (T3) years later respectively. Routine clinical and laboratory data were collected at each visit. Mixed linear regression models were used with estimated glomerular filtration rate (eGFR) as the dependent variable.

Results

A total of 123 patients were included with a mean follow-up of 2.12 ± 0.45 years after ABPM. Mean age and eGFR at T1 were 56.0 ± 15.1 and 54.9 ± 20.0 mL/min/1.73m² respectively. 61 patients (50.4%) had sustained HT and 81 (65.8%) were non-dippers. In multivariate analysis, systolic dipping status was positively associated with eGFR (p = 0.009) and compared to non-dippers, dippers had a 10.4 mL/min/1.73m² higher eGFR. HT was negatively associated with eGFR (p = 0.003).

Conclusions

We confirm a high prevalence of non-dippers in KTX recipients. We suggest that preserved systolic dipping is associated with improved renal function in this setting independently of potential confounders, including HT and proteinuria. Whether modification of dipping status by chronotherapy would preserve renal function remains to be tested in clinical trials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02523-7.

Blood pressure monitoring in kidney transplantation: a systematic review on hypertension and target organ damage

BACKGROUND

Sparse studies show that ambulatory blood pressure monitoring (ABPM) is superior to office BP (oBP) measurements to predict target organ damage and cardiovascular (CV) events in kidney transplant recipients (KTRs). We performed a systematic review aimed at determining the potential associations between BP recordings by different methods and renal and CV outcomes in this population.

METHODS

Major medical databases were searched for studies enrolling adult KTRs undergoing 24h ABPM compared to office or home BP measurements. Main outcomes were: associations between different BP recordings and renal and CV outcomes. Additionally, any association between the circadian BP pattern (dipping/non-dipping status) and outcomes was assessed.

RESULTS

Twenty-two studies (2078 participants) were reviewed. Amongst 12 studies collecting data on renal endpoints, ten studies found that BP assessed by ABPM was a stronger predictor of renal function decline, assessed by serum creatinine (SCr) and/or creatinine clearance (CrCl) or estimated glomerular filtration rate (eGFR), than traditional office measurements. Twelve studies analyzed the relation between different BP recordings and CV target organ damages and reported robust correlations between echocardiographic abnormalities [i.e. left ventricular mass index (LVM/LVMI)] and 24h ABPM, but not with office BPs. Furthermore, 24h ABPM correlated better than oBP with markers of vascular damage, such as carotid intima-media thickness (IMT), diffuse thickening, and endothelial dysfunction. Additionally, abnormal circadian BP pattern (non-dippers and reverse dippers) identified a group of kidney recipients at risk for kidney function loss and CV abnormalities.

CONCLUSIONS

In our systematic review, ABPM reflected target organ damage more closely than oBP in KTRs. Furthermore, altered circadian BP profile associated with renal and CV target organ damages.

Restoration of nocturnal blood pressure dip and reduction of nocturnal blood pressure with evening anti-hypertensive medication administration in pediatric kidney transplant recipients: A pilot randomized clinical trial

Non-dipping and nocturnal hypertension are commonly found during ABPM in pediatric kidney transplant recipients. These entities are independently associated with increased cardiovascular disease risk in adults. Kidney transplant recipients aged 5-21 years with eGFR > 30 mL/min/1.73 m² and ABPM demonstrating non-dipping status and normal daytime BP were randomized to intervention (short acting BP medication added in the evening) or control (no medication change) in this pilot, randomized, open-label, blinded end-point clinical trial. ABPM, echocardiography, and PWV were performed at baseline, 3 months, and 6 months. The trial included 17 intervention and 16 control participants. Conversion to dipper status occurred in 53.3% vs 7.7% (P = .01) at 6 months for intervention and controls, respectively. Systolic dip was greater in the intervention group compared to controls (10.9 ± 4.5 vs 4.2 ± 4.6, P = .001), and average systolic nighttime BP was significantly lower in the intervention group (106 ± 8.3 vs 114.9 ± 9.5 mm Hg, P = .01) at 6 months. There were no significant differences in LVMI, PWV, or eGFR between groups. Within-group changes in the intervention group demonstrated improvements in non-dippers, dipping, systolic nighttime BP and nighttime BP load. Restoration of nocturnal dip and improvement in nocturnal BP were observed in the population following chronotherapy. Future studies are needed with larger sample sizes over a longer period of time to delineate the long-term effect of improved nocturnal dip on target organ damage.

Ambulatory Blood Pressure in Chronic Kidney Disease: Ready for Prime Time?

Hypertension is common in patients with chronic kidney disease (CKD) and is the most important modifiable risk factor for CKD progression and adverse cardiovascular events in these patients. Diagnosis and successful management of hypertension are critically dependent on accurate blood pressure (BP) measurement. This is most relevant to CKD patients, in whom BP control is difficult to achieve and in whom early antihypertensive treatment is imperative to prevent kidney and cardiovascular complications. Accumulated data indicate that ambulatory blood pressure monitoring (ABPM) is better in detecting hypertension than office BP measurement. ABPM is also a superior prognostic marker compared with office BP and has successfully identified hypertensive CKD patients at increased risk. Additionally, ABPM provides information on circadian BP variation and short-term BP variability, which is associated with cardiovascular and renal outcomes. This paper reviews the evidence for the usefulness of ABPM in detection and management of hypertension in CKD patients and discusses our current understanding of the pathophysiology of altered circadian BP rhythm and variability in CKD and the role of abnormal BP patterns detected by ABPM in relation to outcomes in CKD. In addition, this Review examines the emerging role of antihypertensive chronotherapy to tailor BP management to the circadian BP pattern abnormality detected by 24-hour ABPM.

The impact of kidney transplantation on 24-hour ambulatory blood pressure in end-stage renal disease patients

In this study, we prospectively investigated the impact of kidney transplantation (KT) on the status of hypertension, including circadian rhythm in end-stage renal disease (ESRD) patients. We performed 24-hour ambulatory blood pressure (BP) monitoring and office BP measurement in 48 patients before and 1 year after KT. According to the nocturnal reduction in systolic BP (ΔSBP), the patients were divided into dippers, non-dippers, and reverse dippers. After KT, the mean BP value in office BP and 24-hour ambulatory BP monitoring did not change, but the proportion of patients taking anti-hypertensive drugs and the pill number significantly decreased. In contrast, the mean ΔSBP significantly decreased, and the proportion of non-dippers and reverse dippers did not decrease. Decrease in ΔSBP after KT was associated with inferior allograft function during follow-up. Our study suggests that KT improved the overall BP level, but it did not affect abnormal circadian rhythm in ESRD patients.

The effects of kidney transplantation on sleep, melatonin, circadian rhythm and quality of life in kidney transplant recipients and living donors

BACKGROUND

Sleep disturbance is an important medical problem in patients with end-stage renal disease. It might be related to the disruption of the body's circadian clock since nocturnal levels of its key biomarker melatonin are markedly reduced. We aimed at investigating whether a change in renal function due to kidney transplantation or donation would modify sleep, melatonin levels, circadian rhythmicity, and quality of life in kidney transplant recipients (KTR) and living donors (LD).

METHODS

In KTR, we assessed saliva melatonin concentrations, sleep quality and daytime sleepiness prior to and at 2 weeks and 3 months after transplantation. In LD, we assessed these parameters prior to and at 3 months after donation. We additionally assessed 24-hour core body temperature (cBT), 24-hour blood pressure profile, and quality of life (QoL) prior to and 3 months after transplantation.

RESULTS

Twenty-three KTR and 23 LD completed the study. Regarding sleep, the amount of nighttime awake minutes tended to be reduced in recipients after transplantation (p = 0.05). Nocturnal melatonin concentrations did not change with transplantation or donation. Blood pressure dipping profile and the two circadian markers dim-light melatonin onset and time of core body temperature minimum did not change. Nevertheless, KTR reported that daytime sleepiness and QoL had improved.

CONCLUSION

Objectively nocturnal sleep quality marginally improved after transplantation. Subjectively patients reported improved QoL and daytime sleepiness scores. Changes in renal function were not associated with modified melatonin secretion or circadian rhythmicity.

Impact of late calcineurin inhibitor withdrawal on ambulatory blood pressure and carotid intima media thickness in renal transplant recipients

BACKGROUND

Calcineurin inhibitors (CNIs) have an unfavorable cardiovascular risk profile in renal transplant recipients. The aim of this substudy was to assess the effects of late CNI or mycophenolate mofetil (MMF) withdrawal on ambulatory blood pressure monitoring and carotid intima media thickness.

METHODS

A total of 119 stable renal transplant recipients on triple regimen with steroids, a CNI and MMF were randomized into either the concentration-controlled CNI or MMF withdrawal groups. Patients were treated for traditional cardiovascular risk factors according to predefined targets. Ambulatory blood pressure monitoring and measurements of intima media thickness were performed at baseline and after 1, 2, and 3 years after randomization.

RESULTS

CNI withdrawal resulted in a significant decline in both ambulatory day- and nighttime blood pressures (daytime: systolic blood pressure, -1.6 mm Hg/y, P=0.018; diastolic blood pressure, -1.3 mm Hg/y, P=0.002; nighttime systolic blood pressure: -1.9 mm Hg/y, P=0.008; diastolic blood pressure: -1.3 mm Hg/y, P=0.014), which was not observed after MMF withdrawal. There was no difference in the proportion of nocturnal nondippers (both groups, 69%, P=0.95). Despite the reduction in ambulatory blood pressure, no effect of CNI withdrawal on carotid intima media thickness was found.

CONCLUSION

In stable renal transplant recipients, late CNI withdrawal from a triple drug regimen decreased blood pressure in comparison with MMF withdrawal but had no specific impact on carotid intima media thickness. Considering the high prevalence of hypertension in patients on CNI therapy, most stable renal transplant recipients may benefit from late CNI withdrawal by improved blood pressure control.

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.

Abnormal circadian blood pressure pattern 1-year after kidney transplantation is associated with subsequent lower glomerular filtration rate in recipients without rejection

Abnormal circadian blood pressure (BP) pattern is common after kidney transplantation but its relationship to long term allograft function is unclear. Of 119 kidney recipients who had ambulatory BP monitoring 1 year from transplantation, 36 patients without history of rejection were selected. Twenty-nine recipients were followed for 4 years and seven for 3 years. Iothalamate glomerular filtration rate (GFR) was obtained at 3 weeks then annually. Dippers (n = 10) had day-night systolic BP (SBP) drop (ΔSBP) of ≥10%, nondippers (n = 15) had ΔSBP 0%-9%, whereas reverse dippers (n = 11) had nocturnal rise in SBP. Compared with dippers, reverse and nondippers had a higher Banff cv score at 1 year (P = .03), lower GFR at last follow-up (73.7 ± 18.1, 55.7 ± 16.3, and 56.6 ± 21 mL/min/1.73 m(2) for dippers, non-, and reverse dippers, respectively, P = .05) and higher kidney function loss (8.0 ± 20, -9 ± 17, and 1 ± 14 mL/min/1.73 m(2) for dippers, non-, and reverse dippers, respectively, P = .02). GFR at 4 years and at last follow-up independently correlated with ΔSBP at 1 year (r = 0.46, P = .01; r = 0.34, P = .03). The current study indicates that abnormal circadian BP pattern at 1 year identifies a group of kidney recipients at risk for increased kidney function loss and lower GFR 3-4 years from transplantation.

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.

Volume-associated ambulatory blood pressure patterns in hemodialysis patients

Although volume excess causes hypertension, whether it also affects circadian patterns of arterial pressures among hemodialysis patients remains unknown. To test the notion of whether volume overload is associated with a unique blood pressure (BP) "signature," a posthoc analysis was performed among 145 patients participating in the Dry-Weight Reduction in Hypertensive Hemodialysis Patients randomized, controlled trial. Using 400 ambulatory BP recordings over 8 weeks composed of 35 302 measurements, the trended cosinor model was found to be the best descriptor of BP chronobiology. The trended cosinor model may be described as a pattern of sinusoidal oscillation around a straight line with an upward trend during the interdialytic period that has an intercept at the postdialysis time. Augmented volume removal therapy reduced the intercept systolic BP and increased the rate of rise in systolic BP over the interdialytic interval but had no effect on the systolic BP fluctuation (amplitude). Thus, an elevated intercept and blunted slope pattern characterize the "volume-overload BP pattern" on ambulatory BP monitoring. Similar changes were seen for diastolic BP. Augmented volume removal therapy neither restored dipping nor was associated with a lag phenomenon for either the wake or the sleep systolic BP. Lowering of systolic BP was greater than diastolic BP such that pulse pressure was reduced. An observational cohort of 37 patients followed for 6 months confirmed these findings. Randomized trials are now needed to evaluate the clinical impact of augmented volume removal therapy on hard outcomes, because reduction of pulse pressure with this simple expedient has the potential to improve survival in hemodialysis patients.

Cardiovascular disease in transplant recipients: current and future treatment strategies

A cardiovascular disease event in a transplant recipient may be the result of a pretransplantation disease process, a direct effect of immunosuppressant medications, or the result of exposure to a variety of traditional and nontraditional risk factors after transplantation. Although the understanding of posttransplantation cardiovascular disease remains incomplete, there is evidence that the impact of posttransplantation cardiovascular disease has been decreased, through increased attention to this problem. In the absence of controlled studies to guide therapy, this review summarizes treatment of cardiovascular disease risk factors for which there is strong evidence of benefit in the nontransplantation setting, observational evidence of a similar risk in transplant recipients, and evidence that treatment can be safely administered to transplant recipients. Putative risk factors for posttransplantation cardiovascular disease for which the current level of evidence is insufficient to support specific treatment recommendations are also discussed. Potential new strategies to decrease the risk for cardiovascular disease events after transplantation in the future, including aggressive pretransplantation risk reduction, individualized treatments to prevent different types of cardiovascular disease, dedicated efforts to reduce cardiovascular disease events during transitions between dialysis and transplantation, and manipulation of immunosuppressant protocols, are also introduced.

Diurnal blood pressure changes one year after kidney transplantation: relationship to allograft function, histology, and resistive index

Loss of circadian BP change has been linked to target organ damage and accelerated kidney function loss in hypertensive patients with and without chronic kidney disease. Ambulatory BP-derived data from 119 consecutive kidney transplant recipients who presented for the first annual evaluation were examined in relation to allograft function, histology, and ultrasound findings. A total of 101 (85%) patients were receiving antihypertensive medications (median 2), and 85 (71%) achieved target awake average systolic BP (SBP) of <135 mmHg. A day-night change in SBP by 10% or more (dippers) was detected in 29 (24%). Dipping status was associated with younger recipient age, lack of diabetes, low chronic vascular score, and low resistive index. Nondippers and reverse dippers had lower GFR compared with dippers (P = 0.04). For every 10% nocturnal drop in SBP, GFR increased by 4.6 ml/min per 1.73 m(2) (R = 0.3, P = 0.003). Nondippers and reverse dippers were equally common in recipients with normal histology and in those with pathologic findings on surveillance biopsy. On multivariate analysis, percentage of nocturnal fall in SBP and elevated resistive index independently correlated with GFR. This study indicates that lack of nocturnal fall in SBP is related to poor allograft function, high chronic vascular score, and high resistive index irrespective of allograft fibrosis. Further studies are needed to determine whether restoration of normal BP pattern will confer better allograft outcome.