Approach and Management of Hypertension After Kidney Transplantation

Endothelial dysfunction in the kidney transplant population: Current evidence and management strategies

The endothelium modulates vascular homeostasis owing to a variety of vasoconstrictors and vasodilators. Endothelial dysfunction (ED), characterized by impaired vasodilation, inflammation, and thrombosis, triggers future cardiovascular (CV) diseases. Chronic kidney disease, a state of chronic inflammation caused by oxidative stress, metabolic abnormalities, infection, and uremic toxins damages the endothelium. ED is also associated with a decline in estimated glomerular filtration rate. After kidney transplantation, endothelial functions undergo immediate but partial restoration, promising graft longevity and enhanced CV health. However, the anticipated CV outcomes do not happen due to various transplant-related and unrelated risk factors for ED, culminating in poor CV health and graft survival. ED in kidney transplant recipients is an under-recognized and poorly studied entity. CV diseases are the leading cause of death among kidney transplant candidates with functioning grafts. ED contributes to the pathogenesis of many of the CV diseases. Various biomarkers and vasoreactivity tests are available to study endothelial functions. With an increasing number of transplants happening every year, and improved graft rejection rates due to the availability of effective immunosuppressants, the focus has now shifted to endothelial protection for the prevention, early recognition, and treatment of CV diseases.

Diagnostic and therapeutic challenges in implementing hypertension management after kidney transplantation

PURPOSE OF REVIEW

Evidence for blood pressure (BP) measurement and hypertension management in kidney transplant recipients (KTR) remains lacking.

RECENT FINDINGS

Accurate BP measurement technique is a critical component of hypertension management, and 24-h ambulatory BP monitoring remains the gold standard for diagnosis of hypertension in KTR. BP target at different periods posttransplant is uncertain, but likely higher than that in nontransplant patients given factors related to long-standing uremic milieu and kidney transplantation such as vascular calcification altering transplant renal hemodynamic and allograft perfusion and immunosuppression. Dividing BP target into immediate, early, and late posttransplant periods can guide differential diagnoses of hypertension and BP control with a target SBP less than 160 mmHg in general and BP 115-135/65-85 mmHg for adult KTR receiving pediatric kidneys during the immediate posttransplant period, 130/80 mmHg during early and late posttransplant periods. Calcium channel blockers were shown to have favorable graft outcomes. Novel antihypertensive medications for resistant and refractory hypertension and device-based therapies are limited due to KTR's ineligibility for participating in clinical trials.

SUMMARY

In KTR, BP measurement and monitoring practice should follow the standard clinical practice guideline for nontransplant patients by considering posttransplant factors and immunosuppressive state. Novel treatment options required further studies.

Effect of pharmacist care on clinical outcomes and therapy optimization in perioperative settings: A systematic review

PURPOSE

Integration of pharmacists into the perioperative practice has the potential to improve patients' clinical outcomes. The aim of this systematic review is to systematically investigate the evidence on the roles of pharmacists in perioperative settings and the effects of pharmacist interventions on clinical outcomes and therapy optimization.

METHODS

A protocol-led (CRD42023460812) systematic review was conducted using search of PubMed, Embase, CINAHL and Google Scholar databases. Studies that investigated the roles and impact of pharmacist-led interventions in the perioperative settings on clinical outcomes were included. Data were extracted and quality assessed independently by two reviewers using the DEPICT-2 (Descriptive Elements of Pharmacist Intervention Characterization Tool) and the Crowe Critical Appraisal Tool (CCAT), respectively. Studies were grouped according to the clinical area into 5 sections: (1) pain control and opioid consumption; (2) venous thromboembolism (VTE); (3) surgery-related gastrointestinal complications; (4) postoperative medication management; and (5) total parenteral nutritional.

RESULTS

Nineteen studies involving a total of 7,168 patients were included; most studies were conducted in gastrointestinal (n = 7) and orthopedics (n = 6) surgical units. Most included studies (n = 14) employed a multicomponent intervention including pharmaceutical care, education, guideline development, drug information services, and recommendations formulation. The processes of developing the implemented interventions and their structures were seldom reported. Positive impacts of pharmacist intervention on clinical outcomes included significant improvement in pain control and reductions in the incidence of VTE, surgery-related stress ulcer, nausea, and vomiting. There is inconsistency in the findings related to medication management (ie, achieving desired therapeutic ranges) and management of chronic conditions (hypertension and type 2 diabetes).

CONCLUSION

Whilst there is some evidence of positive impacts of pharmacist intervention on clinical outcomes and optimizing drug therapy, this evidence is generally of low quality and insufficient volume. While this review suggests that pharmacists have essential roles in improving the care of patients undergoing surgery, more research with rigorous designs is required.

Extracellular Fluid Volume and Mortality after Kidney Transplantation

Key Points

Background

High extracellular fluid volume (ECV) is associated with an increased risk of death in nontransplanted patients with CKD. By contrast, both the determinants and the prognosis value of ECV in kidney transplant recipients remain unclear.

Methods

We studied a bicentric prospective cohort of 2057 kidney transplant recipients who underwent GFR measurement (mGFR) 3 months after transplantation. We calculated ECV from iohexol plasma disappearance curve and analyzed its association with patient's characteristics and outcomes.

Results

The mean ECV and mGFR were 14.6±2.6 L/1.73 m2 and 52±16 ml/min per 1.73 m2, respectively. Multiple linear regression identified male sex, older donor and recipient ages, deceased donor, nonpreemptive transplantation, diabetes, cardiac arrhythmia, heart failure, proteinuria, and higher mGFR as independent factors associated with increased ECV. In multivariable cause-specific Cox analyzes, higher tertiles of ECV were associated with increased mortality (tertile 1 as reference; hazard ratio [95% confidence interval] for tertile 2: 1.65 [1.11 to 2.47]; tertile 3: 1.80 [1.18 to 2.74]) but not graft loss. Increased ECV, 3 months after transplantation, was a predictor of reduced mGFR at 12 months after adjusting for 3-month mGFR and other confounding factors (β coefficient: −0.06; 95% confidence interval [−0.09 to −0.02]).

Conclusions

An elevated ECV 3 months after kidney transplantation is independently associated with increased mortality and decreased mGFR at 12 months, but not with graft loss.

Prevalence of hypertension and uncontrolled hypertension after solid organ transplantation: a 5-year follow-up of the Swiss Transplant Cohort Study

OBJECTIVE

Hypertension (HTN) increases cardiovascular risk and is a frequent finding across all solid organ transplant recipients. We describe the prevalence of HTN and uncontrolled HTN, as well as details on pharmacologic treatment of HTN across solid organs transplant recipients up to five years after transplantation.

METHODS

This retrospective study is nested in the prospective Swiss Transplant Cohort Study (www.stcs.ch) that includes kidney, heart, lung, and liver transplantation. Data extraction from 2008 to 2019 was used for this study and follow-up data at 6, 12 and 60 months was analyzed.

RESULTS

A total of 3865 transplant recipients were included for analysis. The prevalence of HTN at 6 and 60 months was 88.9% and 90.4% in kidney (P = 0.21), 61.8% and 76.1% in liver (P < 0.01), 72.6% and 84.9% in lung (P < 0.01), and 89.3% and 85.8% in heart (P = 0.33) transplant recipients, respectively. The prevalence of uncontrolled HTN at 6 and 60 months was 40.3% and 38.9% in kidney (P = 0.48), 21.2% and 30.5% in liver (P = 0.05), 26.0% and 36.8% in lung (P = 0.03) and 38.9% and 18.5% in heart (P < 0.01) transplant recipients, respectively. At 12 months, compared to heart transplant recipients, kidney [odds ratio (OR) = 1.6, 95% confidence interval (CI) 1.1-2.1], liver (OR = 1.7, 95% CI 1.1-2.6) and lung (OR = 2.6, 95% CI 1.6-4.0) transplant recipients had a higher likelihood of presenting with uncontrolled HTN.

CONCLUSION

HTN prevalence after solid organ transplantation is high. Uncontrolled and untreated HTN remain a major issue post transplantation, particularly in organ recipients not necessarily suffering from cardiovascular diseases such as liver or lung transplant recipients.

Exploring the nexus: The place of kidney diseases within the cardiovascular-kidney-metabolic syndrome spectrum

Cardiovascular-kidney-metabolic (CKM) syndrome and chronic kidney disease (CKD) are two significant comorbidities affecting a large proportion of the general population with considerable crosstalk. In addition to substantial co-incidence of CKD and CKM syndrome in epidemiological studies, clinical and pre-clinical studies have identified similar pathophysiological pathways leading to both entities. Patients with CKM syndrome are more prone to develop acute kidney injury and CKD, while therapeutic alternatives and their success rates are considerably lower in such patient groups. Nevertheless, the association between CKM syndrome and CKD or ESKD is bidirectional rather than being a cause-effect relationship as patients with CKD are also prone to develop peripheral insulin resistance, high blood pressure, and dyslipidemia. Furthermore, such patients are less likely to receive kidney transplantation in addition to the higher allograft dysfunction risk. We hereby aim to evaluate the association in-between kidney diseases and CKM syndrome, including epidemiological data, pre-clinical studies with pathophysiological pathways, and potential therapeutic perspectives.

Posttransplant complications: molecular mechanisms and therapeutic interventions

Posttransplantation complications pose a major challenge to the long-term survival and quality of life of organ transplant recipients. These complications encompass immune-mediated complications, infectious complications, metabolic complications, and malignancies, with each type influenced by various risk factors and pathological mechanisms. The molecular mechanisms underlying posttransplantation complications involve a complex interplay of immunological, metabolic, and oncogenic processes, including innate and adaptive immune activation, immunosuppressant side effects, and viral reactivation. Here, we provide a comprehensive overview of the clinical features, risk factors, and molecular mechanisms of major posttransplantation complications. We systematically summarize the current understanding of the immunological basis of allograft rejection and graft-versus-host disease, the metabolic dysregulation associated with immunosuppressive agents, and the role of oncogenic viruses in posttransplantation malignancies. Furthermore, we discuss potential prevention and intervention strategies based on these mechanistic insights, highlighting the importance of optimizing immunosuppressive regimens, enhancing infection prophylaxis, and implementing targeted therapies. We also emphasize the need for future research to develop individualized complication control strategies under the guidance of precision medicine, ultimately improving the prognosis and quality of life of transplant recipients.

Impact of Blood Pressure on Allograft Function and Survival in Kidney Transplant Recipients

The optimal target blood pressure for kidney transplant (KT) patients remains unclear. We included 808 KT patients from the KNOW-KT as a discovery set, and 1,294 KT patients from the KOTRY as a validation set. The main exposures were baseline systolic blood pressure (SBP) at 1 year after KT and time-varying SBP. Patients were classified into five groups: SBP <110; 110-119; 120-129; 130-139; and ≥140 mmHg. SBP trajectories were classified into decreasing, stable, and increasing groups. Primary outcome was composite kidney outcome of ≥50% decrease in eGFR or death-censored graft loss. Compared with the 110-119 mmHg group, both the lowest (adjusted hazard ratio [aHR], 2.43) and the highest SBP (aHR, 2.25) were associated with a higher risk of composite kidney outcome. In time-varying model, also the lowest (aHR, 3.02) and the highest SBP (aHR, 3.60) were associated with a higher risk. In the trajectory model, an increasing SBP trajectory was associated with a higher risk than a stable SBP trajectory (aHR, 2.26). This associations were consistent in the validation set. In conclusion, SBP ≥140 mmHg and an increasing SBP trajectory were associated with a higher risk of allograft dysfunction and failure in KT patients.

Antihypertensive treatment for kidney transplant recipients

BACKGROUND

The comparative effects of specific blood pressure (BP) lowering treatments on patient-important outcomes following kidney transplantation are uncertain. Our 2009 Cochrane review found that calcium channel blockers (CCBs) improved graft function and prevented graft loss, while the evidence for other BP-lowering treatments was limited. This is an update of the 2009 Cochrane review.

OBJECTIVES

To compare the benefits and harms of different classes and combinations of antihypertensive drugs in kidney transplant recipients.

SEARCH METHODS

We contacted the Information Specialist and searched the Cochrane Kidney and Transplant Register of Studies up to 3 July 2024 using search terms relevant to this review. Studies in the Register were identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs evaluating any BP-lowering agent in recipients of a functioning kidney transplant for at least two weeks were eligible.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risks of bias and extracted data. Treatment estimates were summarised using the random-effects model and expressed as relative risk (RR) or mean difference (MD) with 95% confidence intervals (CI). Evidence certainty was assessed using Grades of Recommendation, Assessment, Development and Evaluation (GRADE) processes. The primary outcomes included all-cause death, graft loss, and kidney function.

MAIN RESULTS

Ninety-seven studies (8706 participants) were included. One study evaluated treatment in children. The overall risk of bias was unclear to high across all domains. Compared to placebo or standard care alone, CCBs probably reduce all-cause death (23 studies, 3327 participants: RR 0.83, 95% CI 0.72 to 0.95; I2 = 0%; moderate certainty evidence) and graft loss (24 studies, 3577 participants: RR 0.84, 95% CI 0.75 to 0.95; I2 = 0%; moderate certainty evidence). CCBs may make little or no difference to estimated glomerular filtration rate (eGFR) (11 studies, 2250 participants: MD 1.89 mL/min/1.73 m2, 95% CI -0.70 to 4.48; I2 = 48%; low certainty evidence) and acute rejection (13 studies, 906 participants: RR 10.8, 95% CI 0.85 to 1.35; I2 = 0%; moderate certainty evidence). CCBs may reduce systolic BP (SBP) (3 studies, 329 participants: MD -5.83 mm Hg, 95% CI -10.24 to -1.42; I2 = 13%; low certainty evidence) and diastolic BP (DBP) (3 studies, 329 participants: MD -3.98 mm Hg, 95% CI -5.98 to -1.99; I2 = 0%; low certainty evidence). CCBs have uncertain effects on proteinuria. Compared to placebo or standard care alone, angiotensin-converting-enzyme inhibitors (ACEi) may make little or no difference to all-cause death (7 studies, 702 participants: RR 1.13, 95% CI 0.58 to 2.21; I2 = 0%; low certainty evidence), graft loss (6 studies, 718 participants: RR 0.75, 95% CI 0.49 to 1.13; I2 = 0%; low certainty evidence), eGFR (4 studies, 509 participants: MD -2.46 mL/min/1.73 m2, 95% CI -7.66 to 2.73; I2 = 64%; low certainty evidence) and acute rejection (4 studies, 388 participants: RR 1.75, 95% CI 0.76 to 4.04; I2 = 0%; low certainty evidence). ACEi may reduce proteinuria (5 studies, 441 participants: MD -0.33 g/24 hours, 95% CI -0.64 to -0.01; I2 = 67%; low certainty evidence) but had uncertain effects on SBP and DBP. Compared to placebo or standard care alone, angiotensin receptor blockers (ARB) may make little or no difference to all-cause death (6 studies, 1041 participants: RR 0.69, 95% CI 0.36 to 1.31; I2 = 0%; low certainty evidence), eGRF (5 studies, 300 participants: MD -1.91 mL/min/1.73 m2, 95% CI -6.20 to 2.38; I2 = 57%; low certainty evidence), and acute rejection (4 studies, 323 participants: RR 1.00, 95% CI 0.44 to 2.29; I2 = 0%; low certainty evidence). ARBs may reduce graft loss (6 studies, 892 participants: RR 0.35, 95% CI 0.15 to 0.84; I2 = 0%; low certainty evidence), SBP (10 studies, 1239 participants: MD -3.73 mm Hg, 95% CI -7.02 to -0.44; I2 = 63%; moderate certainty evidence) and DBP (9 studies, 1086 participants: MD -2.75 mm Hg, 95% CI -4.32 to -1.18; I2 = 47%; moderate certainty evidence), but has uncertain effects on proteinuria. The effects of CCBs, ACEi or ARB compared to placebo or standard care alone on cardiovascular outcomes (including fatal or nonfatal myocardial infarction, fatal or nonfatal stroke) or other adverse events were uncertain. The comparative effects of ACEi plus ARB dual therapy, alpha-blockers, and mineralocorticoid receptor antagonists compared to placebo or standard care alone were rarely evaluated. Head-to-head comparisons of ACEi, ARB or thiazide versus CCB, ACEi versus ARB, CCB or ACEi versus alpha- or beta-blockers, or ACEi plus CCB dual therapy versus ACEi or CCB monotherapy were scarce. No studies reported outcome data for cancer or life participation.

AUTHORS' CONCLUSIONS

For kidney transplant recipients, the use of CCB therapy to reduce BP probably reduces death and graft loss compared to placebo or standard care alone, while ARB may reduce graft loss. The effects of ACEi and ARB compared to placebo or standard care on other patient-centred outcomes were uncertain. The effects of dual therapy, alpha-blockers, and mineralocorticoid receptor antagonists compared to placebo or standard care alone and the comparative effects of different treatments were uncertain.

Management of hypertension in heart transplant recipients: an ongoing conundrum

PURPOSE OF REVIEW

Hypertension remains one of the most common clinical problems leading to significant posttransplant complications. This study reviews the pathophysiology of hypertension in the postcardiac transplant phase and provides an update on currently available antihypertensive therapies for heart transplant patients.

RECENT FINDINGS

The true prevalence of hypertension in the heart transplant population remains unknown. Effective blood pressure (BP) control is key to prevent left ventricular remodeling, diastolic dysfunction and stroke. Calcium channel blockers (CCBs) are the most commonly and preferred agents in the early posttransplant phase and may have renal protective effects. Angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs) can all be used as second line antihypertensive agents and may have a role in preventing other long-term complications such as calcineurin-inhibitor induced nephropathy. Although more data are needed, sodium-glucose co-transporter 2 inhibitors (SGLT2i) appeared to be well tolerated and could be considered especially in the presence of type diabetes and chronic kidney disease. Conversely, angiotensin receptor-neprilysin inhibition (ARNI) have not been studied in the heart transplant population therefore cannot be recommended at this time.

SUMMARY

Hypertension is very common after heart transplant. Early steroid wean and traditional risk factor modification play an important part in the management of post-heart transplant hypertension. CCB, ACEI, ARB are the preferred antihypertensive agents to improve postcardiac transplant complications. Novel therapies such as SGLT2i appear well tolerated and may have benefits in both BP and glycemic control in heart transplant; however, larger trials are needed.

Are There Differences in Skin Autofluorescence-Measured Advanced Glycation End-Product Levels between Chronic Kidney Disease and Kidney Transplant Recipients?

The aim of this cross-sectional study was to evaluate the differences in the levels of advanced glycation end products (AGE) between patients with chronic kidney disease (CKD) and kidney transplant recipients (KTRs) and to investigate the risk factors for the AGE levels in each group of these patients. There were 217 participants total, of which 99 (45.6%) were KTRs and 118 (54.4%) had CKD. Data on the levels of AGE, body mass composition, anthropometric parameters, central and peripheral blood pressure, and clinical and laboratory parameters were gathered for each study participant. The AGE values of the CKD and KTRs groups did not differ from one another. In both groups, a lower estimated glomerular filtration rate, male sex, and older age were positive predictors for increased AGE values. Furthermore, higher levels of AGE were linked to lower central systolic blood pressure (cSBP) in the CKD group, whilst, in the KTRs group, higher levels of AGE were linked to a shorter time since kidney transplantation (KTx), more years of dialysis prior to KTx, lower levels of trunk visceral fat, the presence of arterial hypertension, and the absence of prescriptions for the antihypertensive medications urapidil and angiotensin II receptor blockers. Further studies are needed to better understand the above associations. Consequently, a personalised multidisciplinary approach to assess the cardiovascular as well as dietary and lifestyle risk factors to reduce the AGE levels in both KTRs and CKD patients may be implemented.

Blood pressure lowering for kidney transplant recipients: systematic review with network meta-analysis

OBJECTIVE

Hypertension affects 50-90% of kidney transplant recipients and is associated with cardiovascular disease and graft loss. We aimed to evaluate the comparative benefits and harms of blood pressure lowering agents in people with a functioning kidney transplant.

METHODS

We conducted a systematic review with network meta-analysis of randomized controlled trials (RCTs). We searched MEDLINE, Embase, and CENTRAL through to October 2023. RCTs evaluating blood pressure lowering agents administered for at least 2 weeks in people with a functioning kidney transplant with and without preexisting hypertension were eligible. Two reviewers independently extracted data. The primary outcome was graft loss. Treatment effects were estimated using random effects network meta-analysis, with treatment effects expressed as an odds ratio (OR) for binary outcomes and mean difference (MD) for continuous outcomes together with their 95% confidence interval (CI). Confidence in the evidence was assessed using GRADE for network meta-analysis.

RESULTS

Ninety-four studies (7547 adults) were included. Two studies were conducted in children. No blood pressure-lowering agent reduced the risk of graft loss, withdrawal because of adverse events, death, cardiovascular or kidney outcomes compared with placebo/other drug class. Angiotensin-converting enzyme inhibitors and angiotensin receptor blocker therapy may incur greater odds of hyperkalemia compared with calcium channel blockers [odds ratio (OR) 5.48, 95% confidence interval (CI) 2.47-12.16; and OR 8.67, 95% CI 2.65-28.36; low certainty evidence, respectively).

CONCLUSION

The evidentiary basis for the comparative benefits and safety of blood pressure lowering agents in people with a functioning kidney transplant is limited to guide treatment decision-making.

Management of kidney transplant recipients for primary care practitioners

Patients with kidney transplants have a significant co-morbidity index, due to a high number of pre-existing conditions and use of immunosuppression medications. These patients are at higher risk of developing conditions such as hypertension, dyslipidemia, post-transplant diabetes, cardiovascular events, and anemia. Moreover, they are particularly susceptible to infections such as urinary tract infections or pyelonephritis, cancers, and gastrointestinal complications such as diarrhea, which in turn may be attributed to medication adverse effects or infectious causes. Along with these concerns, meticulous management of electrolytes and allograft function is essential. Prior to prescribing any new medications, it is imperative to exercise caution in identifying potential interactions with immunosuppression drugs. This review aims to equip primary care practitioners to address these complex issues and appropriate methods of delivering care to this rapidly growing highly susceptible group.

A paradigm shift from office to home-based blood pressure measurement approaches in kidney transplant recipients

PURPOSE OF REVIEW

The unattended blood pressure (BP) readings from home blood pressure (HBP) monitoring should provide more accurate BP readings than attended BP obtained from office blood pressure (OBP). Here, we review evidence supporting the clinical utility of HBP and automatic remote monitoring of blood pressure (ARM-BP) in kidney transplant recipients (KTR).

RECENT FINDINGS

BP from 24-h ambulatory blood pressure monitoring (24-h ABPM) is higher than but better associated with kidney and cardiovascular outcomes compared to OBP and HBP. While there is discordance of BP readings across different BP measurement methods causing BP misclassification, HBP provides BP readings closer to the readings from the 24-h ABPM than those from OBP. Systolic and diastolic BP is better controlled within 30 days after utilizing ARM-BP.

SUMMARY

Compared to OBP, HBP minimizes the attended effect of OBP, and its readings are closer to the gold standard 24-h ABPM. ARM-BP improves BP control in the short term and trials of longer follow-up duration are required to evaluate sustained clinical benefits in KTR. The paradigm of BP monitoring may shift toward HBP, while OBP may be utilized primarily for KTR who cannot perform HBP for hypertension diagnosis and management.

Management of the kidney transplant recipient in the intensive care unit

PURPOSE OF REVIEW

Kidney transplantation is the ideal treatment for patients with chronic kidney disease and end stage renal disease. While centers are performing more transplants every year, the need for organ transplantation outpaces the supply of organ donors. Due to a growing population of patients with advanced kidney disease and a scarcity of kidneys from deceased donors, patients face extended wait times. By the time patients approach transplantation they have multiple comorbidities, in particular cardiovascular complications. Their risk of complications is further compounded by exposure to immunosuppression post kidney transplantation. Kidney transplant recipients (KTRs) are medically complex and may require acute management in the intensive care unit (ICU), as a result of cardiovascular complications, infections, and/or respiratory compromise from lung infections and/or acute pulmonary edema. Acute complication of immunosuppression, such as thrombotic microangiopathy and posterior reversible encephalopathy syndrome may also warrant ICU admission. This review will cover assessment of high-risk complications and management strategies following kidney transplantation.

RECENT FINDINGS

For intensivists caring for KTRs, it is imperative to understand anatomical considerations of the transplanted kidney, unique infectious risks faced by this population, and appropriate modulation of immunosuppression.

SUMMARY

Recognizing potential complications and implementing appropriate management strategies for KTRs admitted to the ICU will improve kidney allograft and patient survival outcomes.

Uncontrolled hypertension is associated with increased risk of graft failure in kidney transplant recipients: a nationwide population-based study

Backgroud

Hypertension is highly prevalent in patients with kidney transplantation caused by transplantation-related immunologic or non-immunologic risk factors. However, whether a strict definition of hypertension (≥130/80 mmHg) and subdivided blood pressure (BP) groups are associated with an increased risk of graft failure after kidney transplantation using a nationwide large cohort study are still unknown.

Methods

Using Korean National Health Insurance Service data, we included 14,249 patients who underwent kidney transplantation from 2002 to 2016. Patients were categorized into five BP groups according to the 2021 Kidney Disease: Improving Global Outcomes practice guidelines for BP management: normal BP (<120/80 mmHg), elevated BP (120-129/ < 80 mmHg), incident hypertension (≥130/80 mmHg), and controlled or uncontrolled hypertension with anti-hypertensive medications.

Results

The primary outcome was graft failure, which occurred in 1934 (13.6%) participants during the 6-year follow-up. After adjusting for covariates, hypertension was associated with a higher risk of graft failure [Adjusted hazard ratio (AHR), 1.70; 95% confidence interval (CI), 1.48-1.96)] than no-hypertension. The AHR for graft failure was the highest in patients with uncontrolled hypertension (AHR, 2.13; 95% CI, 1.80-2.52). The risk of graft failure had a linear relationship with systolic and diastolic BP, and pulse pressure.

Conclusions

In this nationwide population-based study, hypertension ≥130/80 mmHg based on the 2021 KDIGO BP guidelines in kidney transplantion recipients, and elevated systolic and diastolic BP, and pulse pressure were associated with the risk of developing graft failure in kidney transplant recipients.

[Hypertension as a common element of renal transplantation with pressor kidney and posterior reversible encephalopathy syndrome]

Secondary arterial hypertension accounts for only 5-10% of cases of arterial hypertension, hence the importance of its clinical suspicion for diagnosis. One of the most common causes of secondary hypertension is renovascular hypertension, caused by renal hypoperfusion and activation of the renin-angiotensin-aldosterone system. In addition to arterial hypertension being one of the most prevalent cardiovascular risk factors in the population, its poor control can cause acute neurological disorders such as Posterior Reversible Leukoencephalopathy syndrome (PRES), being characteristic the appearance of visuals alterations. Next, we present the case of a kidney transplant patient with well-controlled arterial hypertension with worsening secondary to renal artery stenosis and development of PRES.

Incidence and Factors Associated with Uncontrolled Hypertension at 12 months after Kidney Transplantation in Saudi Arabia

INTRODUCTION

Uncontrolled blood pressure (uBP) after kidney transplantation (KTx) is very common and is associated with significant morbidity. However, studies that assess its incidence and risk factors are limited and outdated in the Middle East.

METHODS

This is a single-center retrospective study of KTx recipients (KTRs) in our center between January 2017 and May 2020 with a 12-month follow-up period. The target of hypertension treatment during the time of this study was <140/90 mm Hg, according to the published guidelines. We divided patients according to their blood pressure (BP) control at 1 year into two groups: controlled BP (cBP) (<140/90) and uBP (≥140/90). We studied the association between uBP and patients' demographics, baseline cardiovascular risk factors, and changes in their metabolic and cardiovascular profile during the first 12 months post-KTx.

RESULTS

A total of 254 KTRs were included. 79.2% developed post-KTx hypertension, 74% were ≥30 years, 58% were men, and 80% were living donor KTRs. The renal replacement modality among our patients pre-KTx was hemodialysis in 78.4%, peritoneal dialysis in 11.5%, and 10.1% underwent preemptive transplantation. At 1 year, 76 (29.9%) KTRs did not attain the target BP goal. Systolic BP (SBP) decreased from baseline to 12 months by 13 ± 24 mm Hg in the cBP group and increased by 8.7 ± 21 mm Hg in the uBP group (p < 0.001). Additionally, diastolic BP (DBP) decreased by 8.5 ± 16.9 mm Hg in the cBP group and increased by 2.3 ± 18.8 mm Hg in the uBP group (p < 0.001). Factors associated with uBP included age (47 vs. 41 years, p = 0.008) and diabetes mellitus (p = 0.012). Contrarily, gender, dialysis vintage, preemptive transplantation, type of dialysis (hemodialysis vs. peritoneal dialysis), type of transplant (living donor KTx vs. deceased donor KTx), and smoking were not different among the two groups. There were no significant differences between the two groups in regard to changes in creatinine, weight, A1c, low-density lipoprotein, and parathyroid hormone levels. Additionally, rate of rejection, new onset diabetes post-transplant, and persistent hyperthyroidism were not different between the groups. However, higher body mass index at 12 months was associated with a higher incidence of uBP (27.2 ± 5.9 vs. 29.2 ± 5.4, p = 0.013). Using multivariate analysis, we found that serum creatinine at 12 months was the only predictor of uBP (OR = 1.005 [1-1.011], p = 0.036).

CONCLUSION

At 1-year post-renal transplantation, about one-third of KTRs had uBP despite multiple antihypertensive medications. SBP and DBP significantly trended upward after transplantation in uBP patients, whereas SBP and DBP significantly trended downward after transplantation in cBP patients. Serum creatinine at 12 months was the only factor independently associated with uBP.

The Flow Cytometric Analysis of Peripheral Blood Lymphocytes and Expression of HLA II Molecules in Lymphocyte During Acute Rejection After Renal Transplantation

Objective

To investigate the changes in the proportion of peripheral blood lymphocytes and the expression of HLA II molecules in lymphocytes during acute rejection after renal transplantation.

Methods

Thirty-five patients who had undergone renal transplantation were selected. Eighteen patients with clinical and pathological confirmed acute rejection were selected as the test group, and twelve patients without clinical acute rejection symptoms were selected as the control group. Flow cytometry analysis was used to determine the proportion of peripheral blood lymphocytes. The mRNA and protein expression of HLA II molecules on peripheral blood lymphocytes were detected using real-time fluorescence quantification and immunoblotting, respectively.

Results

The proportion of T lymphocytes, B lymphocytes, and CD4CD8 double positive T cells in the Control Group were 67.48% ± 5.35%, 10.82% ± 1.26%, and 0.88% ± 0.06%, respectively, and in the Test Group were 87.52% ± 6.28%, 3.36% ± 0.26%, and 0.34% ± 0.03%, with a significant difference respectively. The mRNA and protein expressions of HLA II molecules of peripheral blood B lymphocytes in the control group were significantly higher that these in the test group.

Conclusion

The proportion of peripheral blood T lymphocytes, B lymphocytes, CD4CD8 double positive T cells, and the expression of HLA II molecules of peripheral blood lymphocytes can all indicate the occurrence of acute renal transplantation rejection, which were exceedingly useful to clinicians in judging the acute rejection of renal transplantation in the early stages.

Diagnostic value of neutrophil gelatinase-associated lipocalin (NGAL) as an early biomarker for detection of renal failure in hypertensives: a case-control study in a regional hospital in Ghana

BACKGROUND

Renal failure is one of the most serious vascular effects of hypertension. For better therapy and prevention of complications, early kidney disease identification in these patients is absolutely essential. However, current studies have proposed plasma Neutrophil Gelatinase Associated Lipocalin (pNGAL) to be a better biomarker comparative to serum creatinine (SCr). This study assessed the diagnostic utility of plasma neutrophil gelatinase-associated lipocalin (pNGAL) as a biomarker for early nephropathy diagnosis in hypertensive individuals.

METHODS

This hospital-based case-control study comprised 140 hypertensives and 70 healthy participants. A well-structured questionnaire and patient case notes were used to document relevant demographic and clinical information. 5 ml of venous blood sample was taken to measure fasting blood sugar levels, creatinine, and plasma NGAL levels. All data were analyzed using the Statistical Package for Social Sciences (SPSS release 20.0, copyrite©SPSS Inc.) and a p-value < 0.05 was considered statistically significant.

RESULTS

In this study the plasma neutrophil gelatinase-associated lipocalin (NGAL) levels were significantly higher in cases compared to controls. Hypertensive cases also had significantly higher waist-circumference compared to the control group. The median fasting blood sugar level was significantly higher in cases compared to controls. This study established the use of Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Cockcroft and Gault formula (CG) as the most accurate predictive equations for assessing renal dysfunction. The threshold for NGAL above which renal impairment can be assessed was found to be 109.4 ng/ml (sen-91%, spec. - 68%), 120 ng/ml (sen- 100%, spec- 72%) and 118.6 ng/ml (sen- 83%, spec- 72%) for MDRD, CKD-EPI and CG equations respectively. The prevalence of CKD was 16.4%, 13.6% and 20.7% respectively using the MDRD, CKD-EPI and CG.

CONCLUSION

From this study, pNGAL is a better indicator of kidney impairment in the early stages of CKD as compared with sCr in general hypertensive population.

Infertility, pregnancy and breastfeeding in kidney transplantation recipients: Key issues

Chronic kidney disease (CKD), especially in advanced stages, is an important cause of infertility. In CKD patients, infertility has been linked to multiple factors. The pathophysiology of infertility related to CKD is complex and forked. Correction of modifiable factors can improve fertility in both genders. In males as well as females, successful kidney transplantation offers good chances of restoration of reproductive function. In female renal allograft recipients, recovery of reproductive functions in the post-transplant period will manifest as restoration of normal menses and ovulation. Owing to this improvement, there is a significant risk of unplanned pregnancy, hence the need to discuss methods of contraception before transplantation. In kidney transplant recipients, different contraceptive options for pregnancy planning, have been used. The selection of one contraception over another is based on preference and tolerability. Pregnancy, in renal transplanted females, is associated with physiologic changes that occur in pregnant women with native kidneys. Immunosuppressive medications during pregnancy, in a recipient with a single functioning kidney, expose the mother and fetus to unwanted complications. Some immunosuppressive drugs are contraindicated during pregnancy. Immunosuppressive medications should be discussed with renal transplant recipients who are planning to breastfeed their babies. In addition to antirejection drugs, other medications should be managed accordingly, whenever pregnancy is planned.

Microvascular anastomosis of the human lacrimal gland: a concept study towards transplantation of the human lacrimal gland

Introduction

Severe aqueous tear deficiency is caused by primary or secondary main lacrimal gland insufficiency. The transplantation of a human lacrimal gland could become a potential treatment option to provide physiological tears with optimal properties. To this end, we performed an ex vivo study to develop a surgical strategy that would ensure a vascular supply for a lacrimal gland transplant using microvascular techniques.

Material and methods

Five cadaver heads were used to perform a lateral orbitotomy in order to identify the vascular pedicle and the lacrimal gland itself. The principal feasibility and the time of the required surgical steps for an intraorbital microvascular re-anastomosis of the human lacrimal gland were documented. Patency and potential leakage of the anastomosis were tested with hematoxylin intraoperatively. Postoperatively, routine histological, as well as scanning electron microscopy (SEM) of the gland and vascular anastomosis, were performed.

Results

The vascular pedicle of all five glands could be isolated over a minimum stretch of at least 1 cm, severed, and successfully reanastmosed microsurgically. Time for arterial anatomization (n = 4) was 23 ± 7 min and 22 ± 3 min for the vein (p = 0.62). The total time for the entire microvascular anastomosis was 46 ± 9 min. All anastomosis were patent upon testing. SEM revealed well-aligned edges of the anastomosis with tight sutures in place.

Conclusion

Our study demonstrates as proof of principle the feasibility of intraorbital microvascular re-anastomosis of a human lacrimal gland within the presumed window of ischemia of this tissue. This should encourage orbital surgeons to attempt lacrimal gland transplantation in humans in vivo.

Risk factors for neurocognitive impairment and the relation with structural brain abnormality in children and young adults with severe chronic kidney disease

BACKGROUND

Severe chronic kidney disease (CKD) in children and young adults has shown to be associated with abnormal brain development, which may contribute to neurocognitive impairments. We aimed to investigate risk factors for neurocognitive impairment and investigate the relation with structural brain abnormalities in young severe CKD patients.

METHODS

This cross-sectional study includes 28 patients with severe CKD (eGFR < 30), aged 8-30 years (median 18.5 years), on different treatment modalities (pre-dialysis [n = 8], dialysis [n = 8], transplanted [n = 12]). We assessed neurocognitive functioning using a comprehensive test battery and brain structure by magnetic resonance imaging metrics of brain volume and white matter integrity (fractional anisotropy [FA] and mean diffusivity [MD] measured with diffusion tensor imaging). Multivariate regression and mediation analyses were performed between clinical CKD parameters, brain structure, and neurocognitive outcome.

RESULTS

A combination of risk factors (e.g., longer time since kidney transplantation, longer dialysis duration and late CKD onset) was significantly associated with lower intelligence and/or worse processing speed and working memory. Lower FA in a cluster of white matter tracts was associated with lower intelligence and mediated the relation between clinical risk factors and lower intelligence.

CONCLUSIONS

Young severe CKD patients with a prolonged duration of kidney replacement therapy, either dialysis or transplantation are at particular risk for impairments in intelligence, processing speed, and working memory. Disrupted white matter integrity may importantly contribute to these neurocognitive impairments. Prospective, longitudinal studies are needed to elucidate the mechanisms involved in CKD and treatment that affect white matter integrity and neurocognitive outcome in young patients. A higher resolution version of the Graphical abstract is available as Supplementary information.

Arterial hypertension in kidney transplantation: huge importance, but few answers

Abstract Arterial hypertension (AH) after renal transplantation (RTX) is correlated with worse cardiovascular and renal outcomes, with loss of renal function, decreased graft survival and higher mortality. RTX recipients have discrepant blood pressure (BP) values when measured in the office or by systematic methodologies, such as Ambulatory Blood Pressure Monitoring (ABPM), with significant prevalence of no nocturnal dipping or nocturnal hypertension, white coat hypertension and masked hypertension. The aim of the present study was to review the issue of hypertension in RTX, addressing its multifactorial pathophysiology and demonstrating the importance of ABPM as a tool for monitoring BP in these patients. Treatment is based on lifestyle changes and antihypertensive drugs, with calcium channel blockers considered first-line treatment. The best blood pressure target and treatment with more favorable outcomes in RTX are yet to be determined, through well-conducted scientific studies, that is, in terms of AH in RTX, we currently have more questions to answer than answers to give.

Hipertensão arterial no transplante renal: grande importância, mas poucas respostas

Resumo Hipertensão arterial (HA) no póstransplante renal (TXR) se correlaciona com piores desfechos cardiovasculares e renais, com perda de função renal, diminuição da sobrevida do enxerto e maior mortalidade. Receptores de TXR apresentam valores discrepantes de pressão arterial (PA) quando ela é obtida em consultório ou por metodologias sistematizadas, como a Monitorização Ambulatorial da PA (MAPA), com prevalências significantes de ausência de descenso noturno ou hipertensão noturna, hipertensão do avental branco e hipertensão mascarada. O objetivo do presente estudo foi rever a temática da hipertensão no TXR, abordando sua fisiopatologia multifatorial e demonstrando a importância da MAPA como ferramenta de acompanhamento da PA nesses pacientes. O tratamento é baseado em mudanças no estilo de vida e em fármacos anti-hipertensivos, sendo os bloqueadores de canais de cálcio considerados de primeira linha. A melhor meta pressórica e o tratamento com desfechos mais favoráveis no TXR ainda estão por ser determinados, por meio de estudos bem conduzidos cientificamente, ou seja, em termos de HA no TXR temos atualmente mais questões a responder do que respostas a dar.

The effect of the very low dosage diltiazem on tacrolimus exposure very early after kidney transplantation: a randomized controlled trial

The objective of this study was to assess the effect of the very low dosage of diltiazem on tacrolimus exposure during the first week post-kidney transplantation, among cytochrome P450 (CYP) 3A5 expressers who did not receive diltiazem (EXplb), CYP3A5 expressers who received the very low dose diltiazem (EXdtz), CYP3A5 nonexpressers who did not receive diltiazem (NEplb), and CYP3A5 nonexpressers who received the very low dose diltiazem (NEdtz). Forty kidney recipients who receive tacrolimus-based immunosuppressive regimen were randomly assigned, with stratification on the CYP3A5 genotypes, to receive either diltiazem 30 mg every 12 h or a matched placebo. The observed median dose-adjusted area under the 12-h curve of tacrolimus concentration (AUC/D) at day 7 post-transplantation was lowest in the EXplb group followed by EXdtz, NEplb, and NEdtz at 34.9, 43.6, 49.4, and 71.1 ng*h/mL per mg, respectively. A Kruskal-Wallis test showed a significant difference in the mean ranks of AUC/D among groups. Significant differences between EXplb and NEplb, and between EXplb and NEdtz were demonstrated, whereas no sufficient evidence of significant differences was detected between the other pairs. In conclusion, coadministration of diltiazem 30 mg twice daily may be advantageous for increasing tacrolimus exposure early after kidney transplantation among CYP3A5 expressers.

Hypertension in kidney transplant recipients

Kidney transplantation is considered the treatment of choice for end-stage kidney disease patients. However, the residual cardiovascular risk remains significantly higher in kidney transplant recipients (KTRs) than in the general population. Hypertension is highly prevalent in KTRs and represents a major modifiable risk factor associated with adverse cardiovascular outcomes and reduced patient and graft survival. Proper definition of hypertension and recognition of special phenotypes and abnormal diurnal blood pressure (BP) patterns is crucial for adequate BP control. Misclassification by office BP is commonly encountered in these patients, and a high proportion of masked and uncontrolled hypertension, as well as of white-coat hypertension, has been revealed in these patients with the use of ambulatory BP monitoring. The pathophysiology of hypertension in KTRs is multifactorial, involving traditional risk factors, factors related to chronic kidney disease and factors related to the transplantation procedure. In the absence of evidence from large-scale randomized controlled trials in this population, BP targets for hypertension management in KTR have been extrapolated from chronic kidney disease populations. The most recent Kidney Disease Improving Global Outcomes 2021 guidelines recommend lowering BP to less than 130/80 mmHg using standardized BP office measurements. Dihydropyridine calcium channel blockers and angiotensin-converting enzyme inhibitors/angiotensin-II receptor blockers have been established as the preferred first-line agents, on the basis of emphasis placed on their favorable outcomes on graft survival. The aim of this review is to provide previous and recent evidence on prevalence, accurate diagnosis, pathophysiology and treatment of hypertension in KTRs.

Cardiovascular Risk after Kidney Transplantation: Causes and Current Approaches to a Relevant Burden

Background. Cardiovascular disease is a frequent complication after kidney transplantation and represents the leading cause of mortality in this population. Material and Methods. We searched for the relevant articles in the National Institutes of Health library of medicine, transplant, cardiologic and nephrological journals. Results. The pathogenesis of cardiovascular disease in kidney transplant is multifactorial. Apart from non-modifiable risk factors, such as age, gender, genetic predisposition and ethnicity, several traditional and non-traditional modifiable risk factors contribute to its development. Traditional factors, such as diabetes, hypertension and dyslipidemia, may be present before and may worsen after transplantation. Immunosuppressants and impaired graft function may strongly influence the exacerbation of these comorbidities. However, in the last years, several studies showed that many other cardiovascular risk factors may be involved in kidney transplantation, including hyperuricemia, inflammation, low klotho and elevated Fibroblast Growth Factor 23 levels, deficient levels of vitamin D, vascular calcifications, anemia and poor physical activity and quality of life. Conclusions. The timely and effective treatment of time-honored and recently discovered modifiable risk factors represent the basis of the prevention of cardiovascular complications in kidney transplantation. Reduction of cardiovascular risk can improve the life expectancy, the quality of life and the allograft function and survival.

Kidney Transplant Recipient with Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH) secondary to COVID-19 pneumonia: A Case Report

Background

Currently, COVID-19 is becoming one of the most common causes of viral pneumonia worldwide. In the medical literature, very few case reports describe the association between COVID-19 and the syndrome of inappropriate antidiuretic hormone secretion (SIADH) in kidney transplant patients.

Methods

A 74-year-old immunocompromised man post–kidney transplant presented with nonspecific symptoms consisting of fatigue, malaise, and anorexia. He was also found to have hyponatremia in the context of pulmonary insults. SIADH in the setting of COVID-19 pneumonia was diagnosed after exclusion of other causes of hyponatremia. He was treated for COVID-19 pneumonia with antiviral therapy, secondary bacterial infection prophylaxis, dexamethasone and ventilatory support in addition to modification of antirejection medications.

Results

The patient has improved and his serum sodium normalized with management of primary insult.

Conclusions. SIADH should be suspected in transplant patients with COVID-19 pneumonia once they develops hyponatremia. The decision of intravenous fluid administration should be taken carefully in these settings.

New onset hypertension after transplantation

It has been reported that up to 90% of organ transplant recipients have suboptimal blood pressure control. Uncontrolled hypertension is a well-known culprit of cardiovascular and overall morbidity and mortality. In addition, rigorous control of hypertension after organ transplantation is a crucial factor in prolonging graft survival. Nevertheless, hypertension after organ transplantation encompasses a broader range of causes than those identified in non-organ transplant patients. Hence, specific management awareness of those factors is mandated. An in-depth understanding of hypertension after organ transplantation remains a debatable issue that necessitates further clarification. This article provides a comprehensive review of the prevalence, risk factors, etiology, complications, prevention, and management of hypertension after organ transplantation.

Death With a Functioning Graft Kidney: A Single-Center Experience of More Than 4 Decades

OBJECTIVES

Death with graft function is one of the most catastrophic events after kidney transplant. Various pre and posttransplant risk factors have been linked to death with graft function. Characterization of this event is crucial to set successful preventive measures. Here, we reported on death with graft function among living donor kidney transplant recipients seen at the Urology and Nephrology Centre at Mansoura University (Mansoura, Egypt) throughout a period of >4 decades.

MATERIALS AND METHODS

This single-center study included 2953 patients who received living donor kidney transplant between March 1976 and December 2018. Patient data were retrospectively analyzed. Patients who had death with graft function were compared with other patients with regard to pre- and posttransplant data. Causes of death with graft function were also studied.

RESULTS

Among our patients (1654 male [56%] and 1299 female [44%] patients), death with graft function was reported in 9.9% of patients and responsible for 58.3% of deaths and 24.6% of graft losses. Male sex, pretransplant dialysis and blood transfusion, pre- and posttransplant diabetes and hypertension, high HLA mismatches, antithymocyte globulin induction, steroid and cyclosporine use, steroid dose, acute rejection episodes, and posttransplant infections and malignancy were significantly higher among the death with graft function group. However, multivariate analyses showed that only pretransplant diabetes, steroid dose, and posttransplant infections were risk factors for death with graft function. The most common causes of death with graft function were cardiovascular disease, infections, and malignancy.

CONCLUSIONS

Death with graft function remains a significant hindrance to competent kidney transplant outcomes. We found that the most common contributors to this major event were cardiovascular disease, infections, and malignancy. More attention is needed to modify risk factors of cardiovascular disease, to update implementation policies for posttransplant vaccinations, and to conduct increased malignancy surveillance, as well to adopt less aggressive immunosuppression regimens.

Isolated nocturnal hypertension in pediatric kidney transplant recipients

BACKGROUND

Isolated nocturnal hypertension (INH) is defined as nighttime hypertension in the setting of normal daytime blood pressure (BP), diagnosed by ambulatory BP monitoring (ABPM).

METHODS AND RESULTS

Hypertension affects 60%-80% of pediatric kidney transplant recipients, and INH is the most common type of ambulatory hypertension. INH is associated with an increased prevalence of hypertension-mediated target organ damage such as left ventricular hypertrophy in adults and in pediatric kidney transplant recipients.

CONCLUSION

Ambulatory BP monitoring should be performed annually in all pediatric kidney transplant recipients to diagnose hypertension phenotypes that are not detectable by office BP such as masked hypertension, white-coat hypertension, or INH. Isolated nocturnal hypertension in pediatric transplant patients requires study as a treatment target.

Management of long-term cardiovascular risk factors post organ transplant

PURPOSE OF REVIEW

Cardiovascular disease is one of the leading causes of death in solid organ transplant (SOT) recipients. Early identification of cardiovascular risk factors and their adequate management in this population is key for prevention and improved outcomes.

RECENT FINDINGS

Approximately 80% of SOT present one or more cardiovascular risk factors, with increasing prevalence with time posttransplantation. They are due to the interplay of pretransplant conditions and metabolic consequences of immunosuppressive agents, mainly corticosteroids and calcineurin inhibitors. Among the pharmacological management strategies, statins have shown an important protective effect in SOT.

SUMMARY

Strict surveillance of cardiovascular risk factors is recommended in SOT due to their high prevalence and prognostic implications. Further studies on the best managements strategies in this population are needed.

Kinin B1 Receptor Mediates Renal Injury and Remodeling in Hypertension

Despite many readily available therapies, hypertensive kidney disease remains the second most prevalent cause of end-stage renal disease after diabetes, and continues to burden patient populations and escalate morbidity and mortality rates. Kinin B1 receptor (B1R) activation has been shown to have a role in the development of hypertension, one of the major etiologies for chronic kidney disease. However, the role of B1R in hypertension induced renal injury and remodeling remains unexplored. Using a DOCA-salt-induced hypertensive mouse model, we investigated whether B1R deficiency reduces hypertensive renal injury and fibrosis. To further recognize the translational role of B1R, we examined the expression of B1R and its correlation with collagen deposition in renal biopsies from control and hypertensive kidney disease patients. Our data indicates that renal B1R expression was upregulated in the kidneys of DOCA-salt hypertensive mice. Genetic ablation of B1R protected the mice from DOCA-salt-induced renal injury and fibrosis by preventing inflammation and oxidative stress in the kidney. Cultured human proximal tubular epithelial cells expressed B1R and stimulation of B1R with an agonist resulted in increased oxidative stress. In human kidney biopsy samples, we found that the B1R immunoreactivity was not only significantly increased in hypertensive patients compared to normotensive patients, but also there is a positive correlation between B1R expression and renal fibrosis levels. Taken together, our results identify a critical role of B1R in the development of inflammation and fibrosis of the kidney in hypertension.

A Statistical Prediction Model for Survival After Kidney Transplantation from Deceased Donors

Background

In an environment of limited kidney donation resources, patient recovery and survival after kidney transplantation (KT) are highly important. We used pre-operative data of kidney recipients to build a statistical model for predicting survivability after kidney transplantation.

Material/Methods

A dataset was constructed from a pool of patients who received a first KT in our hospital. For allogeneic transplantation, all donated kidneys were collected from deceased donors. Logistic regression analysis was used to change continuous variables into dichotomous ones through the creation of appropriate cut-off values. A regression model based on the least absolute shrinkage and selection operator (LASSO) algorithm was used for dimensionality reduction, feature selection, and survivability prediction. We used receiver operating characteristic (ROC) analysis, calibration, and decision curve analysis (DCA) to evaluate the performance and clinical impact of the proposed model. Finally, a 10-fold cross-validation scheme was implemented to verify the model robustness.

Results

We identified 22 potential variables from which 30 features were selected as survivability predictors. The model established based on the LASSO regression algorithm had shown discrimination with an area under curve (AUC) value of 0.690 (95% confidence interval: 0.557–0.823) and good calibration result. DCA demonstrated clinical applicability of the prognostic model when the intervention progressed to the possibility threshold of 2%. An average AUC value of 0.691 was obtained on the validation data.

Conclusions

Our results suggest that the proposed model can predict the mortality risk for patients after kidney transplants and could help kidney specialists choose kidney recipients with better prognosis.

What is the goal blood pressure in kidney transplant recipients?

Arterial hypertension is a frequent condition after kidney transplantation and its treatment is a common agenda of the follow- up care. Retrospective data show that treatment of arterial hypertension decreases the risk of kidney graft loss. While randomized controlled trials for target blood pressures in kidney transplant recipients are not available, < 130/80 mm Hg is the most frequently mentioned value. Generally, all classes of antihypertensive drugs can be used, but it is important to consider timing after transplantation and possible interactions with immunosuppressive drugs.

Structural brain abnormalities in children and young adults with severe chronic kidney disease

BACKGROUND

The pathophysiology of neurological dysfunction in severe chronic kidney disease (CKD) in children and young adults is largely unknown. We aimed to investigate brain volumes and white matter integrity in this population and explore brain structure under different treatment modalities.

METHODS

This cross-sectional study includes 24 patients with severe CKD (eGFR < 30) aged 8-30 years (median = 18.5, range = 9.1-30.5) on different therapy modalities (pre-dialysis, n = 7; dialysis, n = 7; transplanted, n = 10) and 21 healthy controls matched for age, sex, and parental educational level. Neuroimaging targeted brain volume using volumetric analysis on T1 scans and white matter integrity with tract-based spatial statistics and voxel-wise regression on diffusion tensor imaging (DTI) data.

RESULTS

CKD patients had lower white matter integrity in a widespread cluster of primarily distal white matter tracts compared to healthy controls. Furthermore, CKD patients had smaller volume of the nucleus accumbens relative to healthy controls, while no evidence was found for abnormal volumes of gray and white matter or other subcortical structures. Longer time since successful transplantation was related to lower white matter integrity. Exploratory analyses comparing treatment subgroups suggest lower white matter integrity and smaller volume of the nucleus accumbens in dialysis and transplanted patients relative to healthy controls.

CONCLUSIONS

Young CKD patients seem at risk for widespread disruption of white matter integrity and to some extent smaller subcortical volume (i.e., nucleus accumbens). Especially patients on dialysis therapy and patients who received a kidney transplant may be at risk for disruption of white matter integrity and smaller volume of the nucleus accumbens.

Mechanisms and management of drug-induced hyperkalemia in kidney transplant patients

Hyperkalemia is a common and potentially life-threatening complication following kidney transplantation that can be caused by a composite of factors such as medications, delayed graft function, and possibly potassium intake. Managing hyperkalemia after kidney transplantation is associated with increased morbidity and healthcare costs, and can be a cause of multiple hospital admissions and barriers to patient discharge. Medications used routinely after kidney transplantation are considered the most frequent culprit for post-transplant hyperkalemia in recipients with a well-functioning graft. These include calcineurin inhibitors (CNIs), pneumocystis pneumonia (PCP) prophylactic agents, and antihypertensives (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta blockers). CNIs can cause hyperkalemic renal tubular acidosis. When hyperkalemia develops following transplantation, the potential offending medication may be discontinued, switched to another agent, or dose-reduced. Belatacept and mTOR inhibitors offer an alternative to calcineurin inhibitors in the event of hyperkalemia, however should be prescribed in the appropriate patient. While trimethoprim/sulfamethoxazole (TMP/SMX) remains the gold standard for prevention of PCP, alternative agents (e.g. dapsone, atovaquone) have been studied and can be recommend in place of TMP/SMX. Antihypertensives that act on the Renin-Angiotensin-Aldosterone System are generally avoided early after transplant but may be indicated later in the transplant course for patients with comorbidities. In cases of mild to moderate hyperkalemia, medical management can be used to normalize serum potassium levels and allow the transplant team additional time to evaluate the function of the graft. In the immediate post-operative setting following kidney transplantation, a rapidly rising potassium refractory to medical therapy can be an indication for dialysis. Patiromer and sodium zirconium cyclosilicate (ZS-9) may play an important role in the management of chronic hyperkalemia in kidney transplant patients, although additional long-term studies are necessary to confirm these effects.

Adherence to antihypertensive drug treatment in kidney transplant recipients

PURPOSE

Hypertension is a common cardiovascular co-morbidity after kidney transplantation and contributes to shortened graft and patient survival outcomes. However, by contrast with adherence to immunosuppressive drugs, adherence to antihypertensive treatment in kidney transplant recipients has been seldom explored. The aim of the current study was to assess adherence to antihypertensive drugs in kidney transplant recipients from the Cliniques Universitaires Saint-Luc and to look for demographic and clinical characteristics associated with drug adherence.

METHODS

Demographic and clinical data were collected from medical files in a standardised case report form. Blood pressure was measured in the sitting position after 5 min rest, using validated oscillometric devices. Drug adherence was assessed by drug dosage in urine using liquid chromatography coupled with tandem mass spectrometry.

RESULTS

Our analysis included 53 kidney transplants recipients (75% of men, mean age: 57.2 ± 12.6 years, time since kidney transplantation: 9.5 ± 7.3 years, blood pressure: 130 ± 16/78 ± 11 mmHg on 2.1 ± 1.1 antihypertensive drugs). The proportion of patients showing full drug adherence, partial drug adherence, and total non-adherence to antihypertensive drugs was 79% (N = 42), 15% (N = 8), and 6% (N = 3), respectively. Adherent patients did not differ from less or non- adherers in any of the analysed characteristics.

CONCLUSION

The proportion of patients adhering to antihypertensive drug treatment among kidney transplant recipients appears similar to that reported for immunosuppressive drugs in renal transplanted patients (∼70%), but much higher than that observed in patients with drug-resistant hypertension (30-40%). Our results need further confirmation in a large, multicenter, prospective cohort.

Role of hypertension in kidney transplant recipients

Cardiovascular events are one of the leading causes of mortality in kidney transplant recipients. Hypertension is the most common comorbidity accompanying chronic kidney disease, with prevalence remaining as high as 90% even after kidney transplantation. It is often poorly controlled. Abnormal blood pressure profiles, such as masked or white-coat hypertension, are also extremely common in these patients. The pathophysiology of blood pressure elevation in kidney transplant recipients is complex and includes transplantation-specific risk factors, which are added to the traditional or chronic kidney disease-related factors. Despite these observations, hypertension management has been an under-researched area in kidney transplantation. Thus, relevant evidence derives either from studies in the general population or from small trials in kidney transplant recipients. Based on the relevant guidelines in the general population, lifestyle modifications should probably be applied as the first step of hypertension management in kidney transplant recipients. The optimal pharmacological management of hypertension in kidney transplant recipients is also not clear. Dihydropyridine calcium channel blockers are commonly used as first line agents because of their lack of adverse effects on the kidney, while other antihypertensive drug classes are under-utilised due to fear of the possible haemodynamic consequences on renal function. This review summarizes the existing data on the pathophysiology, diagnosis, prognostic significance and management of hypertension in kidney transplantation.

Management of the Failing Kidney Transplant: Challenges and Solutions

The kidneys are the most transplanted organs, and the number of failed kidney transplants that require reinstitution of renal replacement therapy in patients is on the increase. Increased mortality has been noted in patients with failed grafts compared with transplant- naïve patients with chronic kidney disease who are treated with dialysis. Issues such as management of immunosuppression, the need for transplant nephrectomy, addressing the increased risk of cardiovascular events, malignancies, and infections are debatable and often based on individual or hospital practices. The optimal timing and modality of renal replacement therapy to be reinitiated are sometimes blurred, with considerable variations among physician practices. Guidelines are therefore needed to appropriately manage this special population of patients with the aim of improving outcomes. Here, our objective was to review the current practices in managing patients with failing kidney transplants so that recommendations can be made based on the available evidence.

Autoimmune-mediated renal disease and hypertension

Hypertension is a major risk factor for cardiovascular disease, chronic kidney disease (CKD), and mortality. Troublingly, hypertension is highly prevalent in patients with autoimmune renal disease and hastens renal functional decline. Although progress has been made over the past two decades in understanding the inflammatory contributions to essential hypertension more broadly, the mechanisms active in autoimmune-mediated renal diseases remain grossly understudied. This Review provides an overview of the pathogenesis of each of the major autoimmune diseases affecting the kidney that are associated with hypertension, and describes the current state of knowledge regarding hypertension in these diseases and their management. Specifically, discussion focuses on Systemic Lupus Erythematosus (SLE) and Lupus Nephritis (LN), Immunoglobulin A (IgA) Nephropathy, Idiopathic Membranous Nephropathy (IMN), Anti-Neutrophil Cytoplasmic Antibody (ANCA)-associated glomerulonephritis, and Thrombotic Thrombocytopenic Purpura (TTP). A summary of disease-specific animal models found to exhibit hypertension is also included to highlight opportunities for much needed further investigation of underlying mechanisms and novel therapeutic approaches.

The Impact of Atherosclerotic Cardiovascular Risk on Graft Failure in Deceased-Donor Renal Transplantation

INTRODUCTION

Pretransplant cardiovascular risk may be amplified after renal transplant, but little is known about its impact on graft outcomes.

RESEARCH QUESTION

The purpose of this study was to determine if pretransplant cardiovascular risk was associated with graft outcomes.

DESIGN

This retrospective study included deceased-donor renal transplant recipients from 2010-2015. Atherosclerotic cardiovascular disease risk for patients without prior disease was calculated and patients were categorized into high (score >20%), intermediate (7.5-20%), and low risk (<7.5%). Patients with and without prior cardiovascular disease were also compared. The main endpoint was graft failure at 3-years post-transplant. Other outcomes included major adverse cardiovascular events, biopsy-proven rejection, and mortality.

RESULTS

In patients without prior atherosclerotic cardiovascular disease (N = 115), graft failure rates (4.5% vs 11.3% vs 12.5%; (P = 0.64) and major adverse cardiovascular events (9.1% vs 13.2% vs 5.0%; P = 0.52) were similar in the high, intermediate, and low risk groups. In those with prior disease (N = 220), rates of primary nonfunction (6.8% vs 1.7%; P = 0.04), major adverse cardiovascular events (7.3% vs 2.6%; P = 0.01), and heart failure (10.9% vs 3.5%; P = 0.02) were higher than those without cardiovascular; rates of major adverse cardiovascular events and heart failure were insignificant after adjusting for age, gender, and race. Other outcomes were not different. Outcomes did not differ based on pretransplant cardiovascular risk.

DISCUSSION

Pretransplant atherosclerotic cardiovascular disease was associated with increased early graft failure but similar outcomes at 3-years, suggesting cardiac risk alone should not exclude transplantation.

Long-term outcome of percutaneous transluminal renal angioplasty (PTRA) versus PTRA with stenting (PTRAS) in transplant renal artery stenosis

Background

Endovascular treatment is standard of care for transplant renal artery stenosis (TRAS). No study has evaluated long-term outcomes compared between percutaneous transluminal renal angioplasty (PTRA) and PTRA with stenting (PTRAS). Accordingly, this study aimed to investigate the 1-year clinical success, and short- and long-term event-free survival between PTRA and PTRAS in patients diagnosed with TRAS at Thailand’s largest national tertiary referral center.

Methods

This single-center retrospective study included kidney transplant patients treated for TRAS during January 2001 to June 2019. Clinical success was defined as (1) increase in estimated glomerular filtration rate (eGFR) > 15%, or (2) reduction in mean arterial pressure (MAP) > 15% with no decrease in antihypertensive medication, or no reduction in MAP or reduction in MAP < 15% with decrease in antihypertensive medication. Incidence of kidney transplant graft failure and transplant renal artery stenosis were also collected.

Results

Sixty-five cases of TRAS were identified from 1072 patients who underwent kidney transplantation. The majority (98.5%) had end-to-side anastomosis technique. Thirty-four patients had PTRA, while 31 patients had PTRAS. One-year clinical success according to renal outcome and BP reduction was 78.5% and 49.2%, respectively. Both renal outcome (79.4% vs. 77.4%, p = 0.845) and BP reduction (40.6% vs. 58.1%, p = 0.166) at 1 year were similar between the PTRA and PTRAS groups. Compared between PTRA and PTRAS, event-free survival for composite of kidney transplant graft failure or transplant renal artery restenosis was significantly higher for PTRAS at 1 year (82.4% vs. 100%, p = 0.025), but not significantly different at 10 years (73.5% vs. 71%, p = 0.818).

Conclusions

We demonstrated the 1-year clinical success, and short- and long-term event-free survival between PTRA and PTRAS in TRAS patients. One-year clinical success was found to be similar between groups. Event-free survival for composite of kidney transplant graft failure or transplant renal artery restenosis was significantly higher in PTRAS at 1 year, but similar between groups at 10 years.

Trial registration Thai Clinical Trials Registry, TCTR20200626002. Registered 26 June 2020—Retrospectively registered, http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trial search&smenu = fulltext&task = search&task2 = view1&id = 6441

Novel approaches to management of hyperkalaemia in kidney transplantation

PURPOSE OF REVIEW

Medications used frequently after kidney transplantation, including calcineurin inhibitors, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta blockers and antimicrobials, are considered the leading culprit for posttransplant hyperkalaemia in recipients with a well functioning allograft. Other risk factors include comorbidities such as diabetes, hypertension and heart failure; and consumption of a potassium-enriched diet. We review the mechanisms for hyperkalaemia following kidney transplantation that are addressed using nonpharmacological and pharmacological interventions. We also discuss emerging therapeutic approaches for the management of recurrent hyperkalaemia in solid organ transplantation, including newer potassium binding therapies.

RECENT FINDINGS

Patiromer and sodium zirconium cyclosilicate are emerging potassium binders approved for the treatment of hyperkalaemia. Patiromer is a polymer that exchanges potassium for calcium ions. In contrast, sodium zirconium cyclosilicate is a nonpolymer compound that exchanges potassium for sodium and hydrogen ions. Both agents are efficacious in the treatment of chronic or recurrent hyperkalaemia and may result in fewer gastrointestinal side effects than older potassium binders such as sodium polystyrene sulfonate and calcium polystyrene sulfonate. Large-scale clinical studies have not been performed in kidney transplant patients. Patiromer may increase serum concentrations of tacrolimus, but not cyclosporine. Sodium zirconium cyclosilicate does not appear to compromise tacrolimus pharmacokinetics, although it may have a higher sodium burden.

SUMMARY

Patiromer and sodium zirconium cyclosilicate may be well tolerated options to treat asymptomatic hyperkalaemia and have the potential to ease potassium dietary restrictions in kidney transplant patients by maintaining a plant-dominant, heart-healthy diet. Their efficacy, better tolerability and comparable cost with respect to previously available potassium binders make them an attractive therapeutic option in chronic hyperkalaemia following kidney transplantation.