Routine Use of Ambulatory Blood Pressure Monitoring in Potential Living Kidney Donors

Ambulatory Blood Pressure Monitoring versus Office Blood Pressure Monitoring to Identify the True Hypertension Status of Living Kidney Donors

Ambulatory blood pressure monitoring (ABPM) is a reliable modality and is preferred over office blood pressure monitoring (OBPM) for detecting hypertension. However, despite its advantages, the utilization of 24-h ABPM in evaluating living kidney donors has not been universally adopted by transplant centers, partly because of the lack of data about the utility of ABPM. This study aimed to identify patients with masked and white-coat hypertension, thereby ensuring appropriate identification of their true hypertension status and assessments of the risk to donors. This study included 73 potential living kidney donors. BP was measured in the office using a standardized protocol as well as by ABPM. Detailed clinical and biochemical parameters were assessed. Target organ damage was assessed in all the donors by assessing proteinuria, hypertensive retinopathy, and echocardiography. Out of the 73 donors, 64.4% were females and 35.6% were males. The average age of individuals in our donor population was 42.0 ± 11.28 years. In total, 31.5% were detected to be hypertensive by OBPM. With ABPM, only 21.9% of donors were hypertensive. The overall prevalence of white-coat hypertension was 30.4%; that of masked hypertension was 6.0%. In donors diagnosed as hypertensive by OBPM, three individuals were identified as having target organ damage. However, two additional donors who were initially missed as hypertensive using OBPM had target organ damage. OBPM overestimated the prevalence of hypertension compared with ABPM. ABPM is the better modality in terms of diagnosing white coats and masked hypertension. ABPM also more reliably correlates with target organ damage than OBPM.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Does This Adult Patient Have Hypertension?: The Rational Clinical Examination Systematic Review

IMPORTANCE

Office blood pressure (BP) measurements are not the most accurate method to diagnose hypertension. Home BP monitoring (HBPM) and 24-hour ambulatory BP monitoring (ABPM) are out-of-office alternatives, and ABPM is considered the reference standard for BP assessment.

OBJECTIVE

To systematically review the accuracy of oscillometric office and home BP measurement methods for correctly classifying adults as having hypertension, defined using ABPM.

DATA SOURCES

PubMed, Cochrane Library, Embase, ClinicalTrials.gov, and DARE databases and the American Heart Association website (from inception to April 2021) were searched, along with reference lists from retrieved articles.

DATA EXTRACTION AND SYNTHESIS

Two authors independently abstracted raw data and assessed methodological quality. A third author resolved disputes as needed.

MAIN OUTCOMES AND MEASURES

Random effects summary sensitivity, specificity, and likelihood ratios (LRs) were calculated for BP measurement methods for the diagnosis of hypertension. ABPM (24-hour mean BP ≥130/80 mm Hg or mean BP while awake ≥135/85 mm Hg) was considered the reference standard.

RESULTS

A total of 12 cross-sectional studies (n = 6877) that compared conventional oscillometric office BP measurements to mean BP during 24-hour ABPM and 6 studies (n = 2049) that compared mean BP on HBPM to mean BP during 24-hour ABPM were included (range, 117-2209 participants per analysis); 2 of these studies (n = 3040) used consecutive samples. The overall prevalence of hypertension identified by 24-hour ABPM was 49% (95% CI, 39%-60%) in the pooled studies that evaluated office measures and 54% (95% CI, 39%-69%) in studies that evaluated HBPM. All included studies assessed sensitivity and specificity at the office BP threshold of 140/90 mm Hg and the home BP threshold of 135/85 mm Hg. Conventional office oscillometric measurement (1-5 measurements in a single visit with BP ≥140/90 mm Hg) had a sensitivity of 51% (95% CI, 36%-67%), specificity of 88% (95% CI, 80%-96%), positive LR of 4.2 (95% CI, 2.5-6.0), and negative LR of 0.56 (95% CI, 0.42-0.69). Mean BP with HBPM (with BP ≥135/85 mm Hg) had a sensitivity of 75% (95% CI, 65%-86%), specificity of 76% (95% CI, 65%-86%), positive LR of 3.1 (95% CI, 2.2-4.0), and negative LR of 0.33 (95% CI, 0.20-0.47). Two studies (1 with a consecutive sample) that compared unattended automated mean office BP (with BP ≥135/85 mm Hg) with 24-hour ABPM had sensitivity ranging from 48% to 51% and specificity ranging from 80% to 91%. One study that compared attended automated mean office BP (with BP ≥140/90 mm Hg) with 24-hour ABPM had a sensitivity of 87.6% (95% CI, 83%-92%) and specificity of 24.1% (95% CI, 16%-32%).

CONCLUSIONS AND RELEVANCE

Office measurements of BP may not be accurate enough to rule in or rule out hypertension; HBPM may be helpful to confirm a diagnosis. When there is uncertainty around threshold values or when office and HBPM are not in agreement, 24-hour ABPM should be considered to establish the diagnosis.

Significance of ambulatory blood pressure monitoring in assessment of potential living kidney donors

The most recent British Transplant Society (BTS) guidelines recommend that office blood pressure (BP) monitoring in living donors is sufficient for the assessment of hypertension (HTN) and those with BP >140/90 should be further assessed using ambulatory BP monitoring (ABPM). ABPM can detect diurnal and nocturnal variation in BP, thus it can identify masked HTN. The aim of the current study is to assess reliability of ABPM vesus office BP monitoring for assessment in living kidney donors. Office and ABPM of all potential kidney donors at a single center from April 2009 to March 2017 were retrospectively reviewed and compared. Age, sex, body mass index, kidney function, and echocardiography results were collected and analyzed. Two hundred and sixteen kidney donors were stratified based on their BP readings into four groups; group 1 (masked HTN: normotensive in office and hypertensive in ABPM), group 2 (sustained normotension: normotensive in office and in ABPM), group 3 (sustained HTN: hypertensive in office and in ABPM), group 4 (white-coat HTN: hypertensive in office and normotensive in ABPM). Thirteen percent of patients were diagnosed with masked HTN. Office systolic BP monitoring was significantly higher in patients older than 50 years old compared to other younger populations. However, this significant difference in systolic BP was diminished when assessment with ABPM was performed. In conclusion, ABPM is a reliable modality for the identification of masked HTN and white coat HTN. Masked HTN is correlated with increased risk of end organ damage and risk of death in potential kidney donors. Transplant physicians cannot rely solely on office BP monitoring in the assessment of potential living kidney donors. ABPM should be integral part of routine assessment of potential living kidney donors.

Diagnostic Performance of Blood Pressure Measurement Modalities in Living Kidney Donor Candidates

BACKGROUND AND OBJECTIVES

Precise BP measurement to exclude hypertension is critical in evaluating potential living kidney donors. Ambulatory BP monitoring is considered the gold standard method for diagnosing hypertension, but it is cumbersome to perform. We sought to determine whether lower BP cutoffs using office and automated BP would reduce the rate of missed hypertension in potential living donors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We measured BP in 578 prospective donors using three modalities: (1) single office BP, (2) office automated BP (average of five consecutive automated readings separated by 1 minute), and (3) ambulatory BP. Daytime ambulatory BP was considered the gold standard for diagnosing hypertension. We assessed both the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7) and the American College of Cardiology/American Heart Association (ACC/AHA) definitions of hypertension in the cohort. Empirical thresholds of office BP and automated BP for the detection of ambulatory BP-diagnosed hypertension were derived using Youden index, which maximizes the sum of sensitivity and specificity and gives equal weight to false positive and false negative values.

RESULTS

Hypertension was diagnosed in 90 (16%) prospective donors by JNC-7 criteria and 198 (34%) prospective donors by ACC/AHA criteria. Masked hypertension was found in 3% of the total cohort by JNC-7 using the combination of office or automated BP, and it was seen in 24% by ACC/AHA guidelines. Using Youden index, cutoffs were derived for both office and automated BP using JNC-7 (<123/82 and <120/78 mm Hg) and ACC/AHA (<119/79 and <116/76 mm Hg) definitions. Using these lower cutoffs, the sensitivity for detecting hypertension improved from 79% to 87% for JNC-7 and from 32% to 87% by ACC/AHA definition, with negative predictive values of 95% and 87%, respectively. Missed (masked) hypertension was reduced to 2% and 4% of the entire cohort by JNC-7and ACC/AHA, respectively.

CONCLUSIONS

The prevalence of hypertension was higher in living donor candidates using ACC/AHA compared JNC-7 definitions. Lower BP cutoffs in the clinic improved sensitivity and led to a low overall prevalence of missed hypertension in prospective living kidney donors.

To Study the Impact of Donor Nephrectomy on Blood Pressure as Measured by Ambulatory Blood Pressure Monitoring and Renal Function

Prospective living kidney donors need meticulous evaluation prior to kidney donation. Ambulatory blood pressure monitoring (ABPM) is considered the reference standard for diagnosing hypertension. With no prior study available in India in this context, we undertook this study to evaluate the utility of ABPM in kidney donors and effect of donor nephrectomy on renal function. This was a prospective observational study involving healthy prospective kidney donors between 18 and 70 years with normal office blood pressure measurements (OBPM). Detailed clinical and biochemical parameters were recorded. OBPM and 24-hour ABPM was done preoperatively and 3 months following donor nephrectomy. There were 51 donors with a mean age of 46.1 ± 11.3 years, of which 40 (78.4%) were females. Preoperatively, three (5.8%) donors were hypertensive on ABPM but normal on OBPM (P = 0.08). Three months post nephrectomy, hypertension was present in seven (13.7%) donors by ABPM, while only two (3.9%) donors were diagnosed as hypertensive by OBPM (P = 0.02). Median pre-nephrectomy proteinuria was 70 mg (10 mg-180 mg) with a mean estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD) formula of 86.86 ± 19.1 ml/min. Six donors developed >300 mg/day proteinuria, and 17 (33.3%) had a 24-hour urinary protein excretion greater than 150 mg/day. Mean serum creatinine (0.79 ± 0.11 vs 1.03 ± 0.16 mg/dl) significantly increased post donation, more so in donors >55 years of age (1.14 ± 0.25 mg/dl). Our study shows that in transplant donors, ABPM is better for diagnosing hypertension, which otherwise remains masked in 10% of the donors on routine OBPM. Significance of post-nephrectomy hypertension and increasing proteinuria needs further evaluation.

Investigating kidney donation as a risk factor for hypertension and microalbuminuria: findings from the Swiss prospective follow-up of living kidney donors

OBJECTIVES

To assess the role of nephrectomy as a risk factor for the development of hypertension and microalbuminuria.

DESIGN

Prospective, long-term follow-up study.

SETTING

Swiss Organ Living-Donor Health Registry.

PARTICIPANTS

All living kidney donors in Switzerland between 1993 and 2009.

INTERVENTIONS

Data on health status and renal function before 1 year and biennially after donation were collected.

PRIMARY AND SECONDARY OUTCOME MEASURES

Comparison of 1-year and 5-year occurrences of hypertension among normotensive donors with 1-year and 5-year estimates from the Framingham hypertension risk score. Multivariate random intercept models were used to investigate changes of albumin excretion after donation, correcting for repeated measurements and cofactors such as age, male gender and body mass index.

RESULTS

A total of 1214 donors contributed 3918 data entries with a completed biennial follow-up rate of 74% during a 10-year period. Mean (SD) follow-up of donors was 31.6 months (34.4). Median age at donation was 50.5 years (IQR 42.2-58.8); 806 donors (66.4%) were women. Donation increased the risk of hypertension after 1 year by 3.64 (95% CI 3.52 to 3.76; p<0.001). Those participants remaining normotensive 1 year after donation return to a risk similar to that of the healthy Framingham population. Microalbuminuria before donation was dependent on donor age but not on the presence of hypertension. After nephrectomy, hypertension became the main driver for changes in albumin excretion (OR 1.19; 95% CI 0.13 to 2.25; p=0.03) and donor age had no effect.

CONCLUSIONS

Nephrectomy propagates hypertension and increases susceptibility for the development of hypertension-induced microalbuminuria.

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.

Effects of preexistent hypertension on blood pressure and residual renal function after donor nephrectomy

BACKGROUND

Living kidney donor selection has become more liberal with acceptation of hypertensive donors. Here, we evaluate short-term and 1- and 5-year renal outcome of living kidney donors with preexistent hypertension.

METHODS

We compared outcome of hypertensive donors by gender, age, and body mass index with matched control donors. Hypertension was defined as predonation antihypertensive drug use. All donors had glomerular filtration rate (I-iothalamate) and effective renal plasma flow (I-hippuran) measured 4 months before and 2 months after donation. A subset of donors had serum creatinine measured 1 year after donation or a renal function measurement 5 years after donation.

RESULTS

Included were 47 hypertensive donors and 94 control donors (both 53% male; mean age, 57±7 years; and body mass index, 28±4 kg/m). Pre- and early postdonation, systolic blood pressure, and mean arterial pressure were significantly higher in hypertensive donors. Control donors showed a rise in diastolic blood pressure after donation, and thus the predonation difference was lost postdonation. Both at 1 year (29 hypertensive donors, 58 controls) and 5 years after donation (13 hypertensive donors and 26 controls) blood pressure was similar. Renal function was similar at all time points.

DISCUSSION

In summary, hypertensive living kidney donors have similar outcome in terms of blood pressure and renal function as control donors, early and 1 and 5 years after donation.

Living donor kidney donation: another form of white coat effect

BACKGROUND/AIMS

Living donor nephrectomy can be associated with increases in blood pressure several years following the procedure, but the best method to assess blood pressure during the living donor evaluation process is unclear.

METHODS

Living kidney donors underwent casual clinic and ambulatory blood pressure monitoring (ABPM) and measurement of central aortic pressures at baseline and 6 months following donor nephrectomy.

RESULTS

There was a significant decline in clinic systolic blood pressure (SBP; p = 0.001) and central aortic systolic pressure (p = 0.011) during the study period. However, average ABPM was unchanged and other measures of central arterial pressures and Augmentation Index were unchanged at 6 months compared to baseline.

CONCLUSIONS

The remarkable differences between clinic SBP and ambulatory SBP prior to donation, and the disappearance of these differences 6 months later, suggest a substantial white coat effect on SBP associated with living kidney donor evaluation. Also, ABPM represents a better way to assess blood pressure prior to kidney donation.

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.