Pathophysiology of hypertension in renal failure

THE RISKS OF FIRST ONSET PRIMARY HYPERTENSION DIAGNOSIS IN THERMAL-INJURED PATIENTS

ABSTRACT

Introduction: Hypertension is a prevalent condition in the United States and leads to an increased risk of developing various comorbidities. However, the impact of new-onset hypertension after severe burns on patient outcomes is not known. We posit that hypertension onset after severe burn is associated with increased risk of developing comorbidities and mortality. Methods: Using the TriNetX database, burned patients diagnosed with essential hypertension after injury were compared with those who did not develop hypertension; neither had prior hypertension. Each cohort was grouped by sex, percent total body surface area (TBSA) burned, and age, then propensity matched for sex, race, ethnicity, and laboratory values. Outcomes assessed were acute kidney injury (AKI), hyperglycemia, heart failure, myocardial infarction (MI), and death. Results: Those diagnosed with hypertension after severe burn were 4.9 times more likely to develop AKI, 3.6 times for hyperglycemia, 5.3 times for heart failure, 4.7 times for acute MI, and 1.5 times for mortality. Sex analysis shows that men were at greater risk for AKI (1.5 times), heart failure (1.1 times), and death (1.4 times). Women were 1.3 times more likely to develop hyperglycemia. Percent TBSA burned grouping showed increased risk for all outcomes with increasing severity. Age grouping indicated an elevated risk of developing AKI, heart failure, acute MI, and death. Conclusion: New-onset hypertension diagnosis in severely burned patients is associated with acute kidney injury, heart failure, acute MI, and death. Overall, males, older patients, and those with a higher % TBSA burned are at a higher risk of developing these comorbidities.

The feasibility, efficacy, and safety of RDN procedure using CO2 angiography through radial artery in severe chronic kidney disease patients

The recent evidence regarding the effectiveness of renal denervation (RDN) in blood pressure control is becoming increasingly substantial. However, many studies have excluded populations with severely impaired kidney function, even though these individuals have a higher prevalence of hypertension compared to the general population, and controlling their blood pressure is more challenging. The effectiveness and safety of RDN in patients with severe chronic kidney disease (CKD) lack strong evidence support. Concerns about worsening kidney function still exist, particularly in patients with CKD stage 5. We conducted an observational study involving 10 patients who were using at least 3 different antihypertensive medications and had an estimated glomerular filtration rate (eGFR) < 45 mL/min/1.73 m2 but had not undergone dialysis. For these patients, we performed RDN via the radial artery approach, with the assistance of carbon dioxide (CO2) angiography. Utilizing this approach, the systolic 24-hour ambulatory blood pressure monitoring did not exhibit a significant decrease at 3 months; however, a significant reduction was observed at 6 months after RDN. We also minimized contrast agent usage, observed no kidney function decline 3 months post-RDN, and experienced no vascular-related complications. Using the radial artery approach and CO2 angiography assistance for RDN may be an effective and safe blood pressure control method for patients with severe kidney impairment.

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.

Potential mechanisms of multimodal prehabilitation effects on surgical complications: a narrative review

Continuous advances in prehabilitation research over the past several decades have clarified its role in improving preoperative risk factors, yet the evidence demonstrating reduced surgical complications remains uncertain. Describing the potential mechanisms underlying prehabilitation and surgical complications represents an important opportunity to establish biological plausibility, develop targeted therapies, generate hypotheses for future research, and contribute to the rationale for implementation into the standard of care. In this narrative review, we discuss and synthesize the current evidence base for the biological plausibility of multimodal prehabilitation to reduce surgical complications. The goal of this review is to improve prehabilitation interventions and measurement by outlining biologically plausible mechanisms of benefit and generating hypotheses for future research. This is accomplished by synthesizing the available evidence for the mechanistic benefit of exercise, nutrition, and psychological interventions for reducing the incidence and severity of surgical complications reported by the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP). This review was conducted and reported in accordance with a quality assessment scale for narrative reviews. Findings indicate that prehabilitation has biological plausibility to reduce all complications outlined by NSQIP. Mechanisms for prehabilitation to reduce surgical complications include anti-inflammation, enhanced innate immunity, and attenuation of sympathovagal imbalance. Mechanisms vary depending on the intervention protocol and baseline characteristics of the sample. This review highlights the need for more research in this space while proposing potential mechanisms to be included in future investigations.

Declined Humoral Immunity of Kidney Transplant Recipients to SARS-CoV-2 Vaccines

Background

Kidney transplant recipients (KTRs) commonly suffer from impaired immunity. KTRs' compromised immune response to COVID-19 vaccines indicates urgent revision of immunisation policies.

Methods

A cross-sectional study was conducted in Madinah, Saudi Arabia of 84 KTRs who had received at least one dose of a COVID-19 vaccine. ELISA was used to evaluate anti-spike SARS-CoV-2 IgG and IgM antibody levels in blood samples obtained one month and seven months after vaccination. Univariate and multivariate analyses were performed to identify associations between seropositive status and factors such as the number of vaccine doses, transplant age, and immunosuppressive therapies.

Results

The mean age of KTRs was 44.3 ± 14.7 years. The IgG antibody seropositivity rate (n=66, 78.5%) was significantly higher than the seronegativity rate (n=18, 21.4%) in the whole cohort (p<0.001). In KTRs seroconverting after one month (n=66), anti-SARS-CoV-2 IgG levels declined significantly between one month (median [IQR]:3 [3-3]) and seven months (2.4 [1.7-2.6]) after vaccination (p<0.01). In KTRs with hypertension, IgG levels significantly decreased between one and seven months after vaccination (p<0.01). IgG levels also decreased significantly in KTRs with a transplant of >10 years (p=0.02). Maintenance immunosuppressive regimens (triple immunosuppressive therapy and steroid-based and antimetabolite-based regimens) led to a significant decrease in IgG levels between the first and second sample (p<0.01). KTRs receiving three vaccine doses showed higher antibody levels than those receiving a single dose or two doses, but the levels decreased significantly between one (median [IQR]: 3 [3-3]) and seven months (2.4 [1.9-2.6]) after vaccination (p<0.01).

Conclusion

KTRs' humoral response after SARS-CoV-2 vaccination is dramatically inhibited and wanes. Antibody levels show a significant decline over time in KTRs with hypertension; receiving triple immunosuppressive therapy or steroid-based or antimetabolite-based regimens; receiving mixed mRNA and viral vector vaccines; and with a transplant of >10 years.

Prognostic Potential of the Body Composition Indices in Predicting Positive Changes in Resting Blood Pressure after High-Intensity Interval Training in Adolescents

This study aimed to investigate the prognostic potential of body composition indices in predicting the improvement in resting blood pressure after 10 weeks of high-intensity interval training (HIIT) implemented in physical education lessons. The participants were 141 adolescents aged 16 years. Independent variables were body mass index (BMI), fat mass index (FMI), muscle mass index (SMI), and mass to fat ratio (MFR); dependent variables were systolic and diastolic blood pressure (SBP, DBP) and its indices: pulse pressure (PP), mid-blood pressure (MBP), and mean arterial pressure (MAP). The receiver operating curve (ROC) method was employed. SMI and MFR are body composition indices with prognostic potential to predict positive changes in SBP in males (SMI: AUC = 0.82; p < 0.001, MFR = 0.70; p = 0.039) and MFR in females (AUC = 0.72; p = 0.035). The respective cut-off point values used to classify participants as a beneficiary of HIIT intervention concerning SBP were SMI = 7.84 and MFR = 2.43 in males, and for SMI = 10.12 and MFR = 1.94 in females. Body composition indices based on skeletal muscle (SMI, MFR) were more likely to predict positive changes in SBP after HIIT intervention in adolescents. PP, MBP, and MAP did not reflect the detecting power of SMI and MFR. However, these thresholds' utility is limited to adolescents of 16 years of age.

Hypertension in chronic kidney disease: What lies behind the scene

Hypertension is a frequent condition encountered during kidney disease development and a leading cause in its progression. Hallmark factors contributing to hypertension constitute a complexity of events that progress chronic kidney disease (CKD) into end-stage renal disease (ESRD). Multiple crosstalk mechanisms are involved in sustaining the inevitable high blood pressure (BP) state in CKD, and these play an important role in the pathogenesis of increased cardiovascular (CV) events associated with CKD. The present review discusses relevant contributory mechanisms underpinning the promotion of hypertension and their consequent eventuation to renal damage and CV disease. In particular, salt and volume expansion, sympathetic nervous system (SNS) hyperactivity, upregulated renin–angiotensin–aldosterone system (RAAS), oxidative stress, vascular remodeling, endothelial dysfunction, and a range of mediators and signaling molecules which are thought to play a role in this concert of events are emphasized. As the control of high BP via therapeutic interventions can represent the key strategy to not only reduce BP but also the CV burden in kidney disease, evidence for major strategic pathways that can alleviate the progression of hypertensive kidney disease are highlighted. This review provides a particular focus on the impact of RAAS antagonists, renal nerve denervation, baroreflex stimulation, and other modalities affecting BP in the context of CKD, to provide interesting perspectives on the management of hypertensive nephropathy and associated CV comorbidities.

The high-intensity interval training introduced in physical education lessons decrease systole in high blood pressure adolescents

Increased resting blood pressure (BP) is a risk factor for many health complications. The prevalence of elevated BP is growing among adolescents. There is a need to investigate effective ways of decreasing excessive blood pressure in this age group. The study aim was to determine the effect of 10-weeks High-Intensive Interval Training (HIIT)—Tabata protocol—introduced in physical education (PE) lessons on resting blood pressure in adolescents. The sample included 52 boys aged 16.23 ± 0.33 years body height176.74 ± 6.07 (m), body weight 65.42 ± 12.51 (kg), BMI 20.89 ± 3.53 (kg/m²) and 89 girls aged 16.12 ± 0.42 years, body height 164.38 ± 6.54 (m), body weight 56.71 ± 10.23 (kg), BMI 20.93 ± 3.08 (kg/m²) from secondary school. Based on resting BP, the fractions of boys and girls with normal BP and high BP were identified and divided into experimental (EG) and control (CG) groups. EG completed a 10-weeks HIIT program (three cycles of Tabata protocol) implemented in one PE lesson during a week. The duration of the effort was 14 min. The intensity was at 75–80% of maximal heart rate. Changes in systolic and diastolic BP after the experiment were examined. The results indicated the improvement in SBP in EG with high BP compared to the rest of the groups (average reduction of 12.77 mmHg; p < 0.0001). The EG normotensive had a statistically significant higher reduction of SBP comparing CG normotensive (average decrease of 1.81 mmHG; p = 0.0089). HIIT effectively decreases BP in adolescents. Implementing HIIT in PE lessons in secondary school is recommended to improve BP parameters.

Effects of Mean Artery Pressure and Blood pH on Survival Rate of Patients with Acute Kidney Injury Combined with Acute Hypoxic Respiratory Failure: A Retrospective Study

Background and Objectives: In the intensive care unit (ICU), renal failure and respiratory failure are two of the most common organ failures in patients with systemic inflammatory response syndrome (SIRS). These clinical symptoms usually result from sepsis, trauma, hypermetabolism or shock. If this syndrome is caused by septic shock, the Surviving Sepsis Campaign Bundle suggests that vasopressin be given to maintain mean arterial pressure (MAP) > 65 mmHg if the patient is hypotensive after fluid resuscitation. Nevertheless, it is important to note that some studies found an effect of various mean arterial pressures on organ function; for example, a MAP of less than 75 mmHg was associated with the risk of acute kidney injury (AKI). However, no published study has evaluated the risk factors of mortality in the subgroup of acute kidney injury with respiratory failure, and little is known of the impact of general risk factors that may increase the mortality rate. Materials and Methods: The objective of this study was to determine the risk factors that might directly affect survival in critically ill patients with multiple organ failure in this subgroup. We retrospectively constructed a cohort study of patients who were admitted to the ICUs, including medical, surgical, and neurological, over 24 months (2015.1 to 2016.12) at Chiayi Chang Gung Memorial Hospital. We only considered patients who met the criteria of acute renal injury according to the Acute Kidney Injury Network (AKIN) and were undergoing mechanical ventilator support due to acute respiratory failure at admission. Results: Data showed that the overall ICU and hospital mortality rate was 63.5%. The most common cause of ICU admission in this cohort study was cardiovascular disease (31.7%) followed by respiratory disease (28.6%). Most patients (73%) suffered sepsis during their ICU admission and the mean length of hospital stay was 24.32 ± 25.73 days. In general, the factors independently associated with in-hospital mortality were lactate > 51.8 mg/dL, MAP ≤ 77.16 mmHg, and pH ≤ 7.22. The risk of in-patient mortality was analyzed using a multivariable Cox regression survival model. Adjusting for other covariates, MAP ≤ 77.16 mmHg was associated with higher probability of in-hospital death [OR = 3.06 (1.374–6.853), p = 0.006]. The other independent outcome predictor of mortality was pH ≤ 7.22 [OR = 2.40 (1.122–5.147), p = 0.024]. Kaplan-Meier survival curves were calculated and the log rank statistic was highly significant. Conclusions: Acute kidney injury combined with respiratory failure is associated with high mortality. High mean arterial pressure and normal blood pH might improve these outcomes. Therefore, the acid–base status and MAP should be considered when attempting to predict outcome. Moreover, the blood pressure targets for acute kidney injury in critical care should not be similar to those recommended for the general population and might prevent mortality.

Associations of Systolic Blood Pressure With Incident CKD G3-G5: A Cohort Study of South Korean Adults

RATIONALE & OBJECTIVE

Clinical practice guidelines recommend a target blood pressure (BP)<130/80 mm Hg to reduce cardiovascular risk. However, the optimal BP to prevent chronic kidney disease (CKD) is unknown.

STUDY DESIGN

Population-based retrospective cohort study.

SETTING & PARTICIPANTS

10.5 million adults who participated in the National Health Insurance Service National Health Checkup Program in South Korea between 2009 and 2015 and had an estimated glomerular filtration rate (GFR) ≥ 60 mL/min/1.73 m² at the beginning of follow-up.

PREDICTORS

Baseline and time-updated systolic BP (SBP) as a continuous variable and categorized as<110, 110 to 119, 120 to 129, 130 to 139, or≥140 mm Hg.

OUTCOME

Incident CKD GFR categories 3 to 5 (CKD G3-G5), defined as de novo development of estimated GFR<60 mL/min/1.73 m² for at least 2 consecutive assessments confirmed at least 90 days apart.

ANALYTICAL APPROACH

Cox proportional hazards regression for baseline BP and marginal structural analysis for time-updated BP.

RESULTS

During 49,169,311 person-years of follow-up, incident CKD G3-G5 developed in 172,423 (1.64%) individuals with a crude event rate of 3.51 (95% CI, 3.49-3.52) per 1,000 person-years. Compared to a baseline SBP of 120 to 129 mm Hg, HRs for incident CKD G3-G5 for the<110, 110 to 119, 130 to 139, and≥140 mm Hg categories were 0.84 (95% CI, 0.82-0.85), 0.92 (95% CI, 0.91-0.94), 1.11 (95% CI, 1.09-1.12), and 1.30 (95% CI, 1.28-1.31), respectively. For time-updated SBPs, corresponding HRs were 0.57 (95% CI, 0.56-0.59), 0.79 (95% CI, 0.78-0.80), 1.58 (95% CI, 1.55-1.60), and 2.49 (95% CI, 2.45-2.53), respectively. Treated as a continuous exposure, each 10-mm Hg higher SBP was associated with 35% higher risk for incident CKD G3-G5 (95% CI, 1.35-1.36).

LIMITATIONS

Use of International Classification of Diseases codes to assess comorbid condition burden; residual confounding, and potential selection bias cannot be excluded.

CONCLUSIONS

In this large national cohort study, higher SBPs were associated with higher risk for incident CKD G3-G5. These findings support evaluation of SBP-lowering strategies to reduce the development of CKD.

The Potential Cardiovascular Benefits of Low-Glucose Degradation Product, Biocompatible Peritoneal Dialysis Fluids: A Review of the Literature

Cardiovascular mortality in the end-stage renal disease (ESRD) population remains the leading cause of death. Targeting traditional cardiovascular risk factors has proven unsuccessful in this patient population, and therefore attention has turned to risk factors related to chronic kidney disease (CKD). The toxicity of high-glucose peritoneal dialysis (PD) solutions has been well documented. The breakdown of glucose into glucose degradation products (GDP) and advanced glycation end-products (AGE) has the ability to alter cell viability and cause premature apoptosis and is strongly correlated with interstitial fibrosis and microvascular sclerosis. Biocompatible solutions have been introduced to combat the hostile milieu to which PD patients are exposed.

Given the considerable cardiovascular burden for PD patients, little is known about the cardiovascular impact the new biocompatible solutions may have. This review analyzes the existing literature regarding the mechanisms through which low-GDP solutions may modulate cardiovascular risk. Interventions using low-GDP solutions have provided encouraging changes in structural cardiovascular measures such as left ventricular mass (LVM), although metabolic changes from reduced GDP and AGE exposure yield inconclusive results on vascular remodelling. It is thought that the local effects of reduced glucose exposure may improve membrane integrity and therefore fluid status. Further research in the form of a robust randomized controlled trial should be carried out to assess the true extent of the cardiovascular benefits these biocompatible solutions may hold.

Serum fibroblast growth factor-23 and incident hypertension: the Atherosclerosis Risk in Communities (ARIC) Study

OBJECTIVE

Elevated serum fibroblast growth factor-23 (FGF23), an endogenous hormone, is associated with disturbed mineral homeostasis, cardiovascular disease, and chronic kidney disease. It is unclear whether FGF23 impacts the development of incident hypertension. We examined the association between elevated FGF23 and incident hypertension in a community-based cohort.

METHOD

We investigated the association of serum FGF23, measured at baseline (1990-1992), with incident hypertension at two follow-up visits (1993-1995 and 1996-1998) in 7948 middle-aged men and women without hypertension at baseline participating in the Atherosclerosis Risk in Communities Study. Incident hypertension was determined by measured blood pressure (DBP ≥ 90 mmHg or SBP ≥ 140 mmHg) and/or self-reported hypertension medication use at follow-up exams. Complementary log-log models that accounted for interval censoring were used to model the association between FGF23 and incident hypertension.

RESULTS

During a median follow-up of 5.9 years, 27% (2152/7948) participants developed hypertension. A nonlinear association between serum FGF23 and incident hypertension was observed; only persons in the highest decile of serum FGF23 had an increased risk of incident hypertension. After adjustment for demographics, behaviors, and adiposity, the hazard ratio for incident hypertension was 1.24 (95% confidence interval: 1.11, 1.39) for the highest decile of FGF23 compared with the lowest quintile. The association was further attenuated in the final model after adjusting for renal function (hazard ratio: 1.21, 95% confidence interval: 1.08, 1.35).

CONCLUSION

High levels (≥60.6 pg/ml) of FGF23 are associated with a modestly increased risk of incident hypertension in the general population, independent of kidney function.

Pharmacologic treatment of hypertension in patients with chronic kidney disease

Hypertension remains an important cause of morbidity and mortality in patients with chronic kidney disease. It both contributes to and is a consequence of chronic renal dysfunction. There is a high prevalence of hypertension in chronic kidney disease, and rates of control remain sub-optimal. Numerous studies have highlighted the benefit of treating hypertension in reducing the overall mortality as well as progression of renal disease in this population. Non-pharmacologic treatment strategies remain the primary intervention in all patients but are insufficient on their own to control hypertension in most cases. Pharmacologic treatment recommendations, however, vary depending on the specific etiology of disease as well as patient characteristics. Though most classes of anti-hypertensive drugs can be used to lower blood pressure in chronic kidney disease, therapy needs to be selected based on the presence of specific co-morbidities as well as the etiology of the kidney disease. Most patients will require multi-drug therapy for achieving target blood pressure goals. This review discusses the pharmacologic options in management of hypertension in various forms of chronic kidney disease.

Online feedback-controlled renal constant infusion clearances in rats

Constant infusion clearance techniques using exogenous renal markers are considered the gold standard for assessing the glomerular filtration rate. Here we describe a constant infusion clearance method in rats allowing the real-time monitoring of steady-state conditions using an automated closed-loop approach based on the transcutaneous measurement of the renal marker FITC-sinistrin. In order to optimize parameters to reach steady-state conditions as fast as possible, a Matlab-based simulation tool was established. Based on this, a real-time feedback-regulated approach for constant infusion clearance monitoring was developed. This was validated by determining hourly FITC-sinistrin plasma concentrations and the glomerular filtration rate in healthy and unilaterally nephrectomized rats. The transcutaneously assessed FITC-sinistrin fluorescence signal was found to reflect the plasma concentration. Our method allows the precise determination of the onset of steady-state marker concentration. Moreover, the steady state can be monitored and controlled in real time for several hours. This procedure is simple to perform since no urine samples and only one blood sample are required. Thus, we developed a real-time feedback-based system for optimal regulation and monitoring of a constant infusion clearance technique.

Hypertension in small animal kidney disease

Kidney disease is commonly associated with hypertension in dogs, cats and other species. There are multiple mechanisms underlying the development of renal hypertension including sodium retention, activation of the renin-angiotensin system and sympathetic nerve stimulation. The relative importance of these and other mechanisms may vary both between species and according to the type of kidney disease that is present. Consideration of underlying disease mechanisms may aid in the rational choice of therapy in hypertensive patients.

Drug therapy in patients with chronic renal failure

BACKGROUND

Roughly 20% of patients in hospital have impaired kidney function. This is frequently overlooked because of the creatinine-blind range in which early stages of renal failure are often hidden. Chronic kidney disease is divided into 5 stages (CKD 1 to 5).

METHODS

Selective literature search.

RESULTS

Methotrexate, enoxaparin and metformin are examples of drugs that should no longer be prescribed if the glomerular filtration rate (GFR) is 60 mL/min or less. With antidiabetic (e.g. glibenclamide), cardiovascular (e.g. atenolol) or anticonvulsive (e.g. gabapentin) drugs, the advice is to use alternative preparations such as gliquidone, metoprolol or carbamazepine which are independent of kidney function. Drug dose adjustment should be considered with antimicrobial (e.g. ampicillin, cefazolin), antiviral (e.g. aciclovir, oseltamivir) and, most recently, also for half of all chemotherapeutic and cytotoxic drugs in patients with impaired kidney function (with e.g. cisplatin, for instance, but not with paclitaxel).

CONCLUSION

Decisions concerning drug dose adjustment must be based on the pharmacokinetics but this is an adequate prerequisite only in conjunction with the pharmacodynamics. There are two different dose adjustment rules: proportional dose reduction according to Luzius Dettli, and the half dosage rule according to Calvin Kunin. The latter leads to higher trough concentrations but is probably more efficient for anti-infective therapy.

Pathogenesis of hypertension in renal failure: role of the sympathetic nervous system and renal afferents

1. The kidney receives a dense innervation of sympathetic and sensory fibres and can be both a target of sympathetic activity and a source of signals that drive sympathetic tone. In the normal state, interactions between the kidney and sympathetic nervous system (SNS) serve to maintain blood pressure and glomerular filtration rate within tightly controlled levels. In renal failure, a defect in renal sodium excretory function leads to an abnormal pressure natriuresis relationship and activation of the renin-angiotensin-aldosterone system, contributing to the development of hypertension and progression of kidney disease. 2. Evidence now strongly indicates a role for the SNS in the pathogenesis of hypertension in renal failure. Hypertension occurs commonly and early in renal disease and is paralleled by increases in SNS activity, as indicated by increased muscle sympathetic nerve activity and circulating catecholamines. This appears to be driven by the diseased kidneys, because nephrectomy or denervation has been shown to correct blood pressure and SNS activity in human and animal studies. 3. Afferent signals from the kidney, detected by chemoreceptors and mechanoreceptors, feed directly into central nuclei of the SNS, including the hypothalamus and circumventricular organs, in addition to the stimulus provided by circulating and brain-derived angiotensin II. Therefore, the pathogenesis of hypertension in renal failure is complex and arises from the interaction of haemodynamic and neuroendocrine factors. 4. Increased SNS activity has significant implications with regard to increased risk of cardiovascular disease and is an important consideration in the treatment of renal failure.

Hypertension in renal disease: Diagnosis and treatment

Hypertension is a common sequela to renal disease in cats and dogs, affecting as many as 61% cats and 93% of dogs, respectively. Undiagnosed and untreated, elevations in blood pressure can have deleterious effects on the brain and heart as well as promote further renal injury. In this article, we discuss the identification of patients at risk for hypertension as well as methods for measuring blood pressure and the treatment of hypertensive patients.

Volume control and blood pressure management in patients undergoing quotidian hemodialysis

BACKGROUND

Hypertension and interdialytic weight gain are associated with left ventricular hypertrophy (LVH), an important predictor of cardiovascular mortality in hemodialysis (HD) patients.

METHODS

In the London Daily/Nocturnal Hemodialysis Study, a group of patients receiving quotidian HD, either short daily (n = 11) or long nocturnal (n = 12), were followed for up to 18 months. Patients were assessed for effects of quotidian HD therapy on blood pressure, interdialytic weight gain, extracellular fluid volume (ECFV), intensity of antihypertensive therapy, and homocysteine levels.

RESULTS

Significant reductions in predialysis mean arterial blood pressure were observed in the daily HD group at 6 months (P < 0.04) and in the nocturnal HD group at 9 months (P < 0.03); these improvements persisted throughout the study period. The daily HD group had a 60% reduction in mean number of antihypertensive tablets per day at 1 month and an 8.8-fold reduction by 18 months. Nocturnal HD patients experienced a 3.3-fold reduction, and control patients, a 1.4-fold increase in mean number of tablets per day by 18 months. By 3 months, the daily HD group showed a significant decrease in interdialytic weight gain (P < 0.0005) and lower ECFV than controls (P < 0.05). The nocturnal HD group had a transient, but significant, increase in interdialytic weight gain at 6 and 15 months (P < 0.05) and no difference in ECFV compared with controls, suggesting a different mechanism of blood pressure control. Homocysteine levels were significantly lower for both quotidian HD groups compared with conventional HD patients.

CONCLUSION

Quotidian HD is a promising therapy with potent antihypertensive effects, resulting in improved blood pressure control. This, together with improved homocysteine levels, may be beneficial in the long term with regard to cardiovascular mortality.