Clinical characteristics of resistant hypertension in renal transplant patients

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.

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.

Changes in Office Blood Pressure Control, Augmentation Index, and Liver Steatosis in Kidney Transplant Patients after Successful Hepatitis C Infection Treatment with Direct Antiviral Agents

Hepatitis C virus (HCV) infection in kidney transplant recipients (KTRs) can be successfully treated with direct antiviral agents (DAA). The aim of our study was to analyze different measures of vascular function during and after the DAA treatment. As we have observed the improvement of blood pressure (BP) control in some individuals, we have conducted an analysis of potential explanatory mechanisms behind this finding. Twenty-eight adult KTRs were prospectively evaluated before and 15 months after start of DAA therapy. Attended office BP (OBP), augmentation index (AIx), pulse wave velocity (PWV), flow-mediated dilation (FMD), liver stiffness measurement (LSM), and liver steatosis assessment (controlled attenuation parameter (CAP)) were measured. In half of the patients, improvement of OBP control (decline of systolic BP by at least 20 mmHg or reduction of the number of antihypertensive drugs used) and parallel central aortic pressure parameters, including AIx, was observed. There was a significant decrease in CAP mean values (241 ± 54 vs. 209 ± 30 dB/m, p < 0.05) only in patients with OBP control improvement. Half of our KTRs cohort after successful HCV eradication noted clinically important improvement of both OBP control and central aortic pressure parameters, including AIx. The concomitant decrease of liver steatosis was observed only in the subgroup of patients with improvement of blood pressure control.

Arterial stiffness but not endothelial dysfunction is associated with multidrug antihypertensive therapy and nondipper blood pressure pattern in kidney transplant recipients

Vascular injury related to chronic kidney disease results in increased arterial stiffness and endothelial dysfunction which may affect arterial blood pressure (BP) and influence patient and graft survival in kidney transplant recipients (KTRs).This cross-sectional study aims to elucidate the relationship between the above-mentioned measures of vascular damage and effectiveness of antihypertensive treatment in KTR.One hundred forty-five KTRs 7.6 ± 2.7 years after transplantation were enrolled in our study. Pulse wave velocity (PWV), flow-mediated dilation (FMD), and nitroglycerin-mediated dilation (NMD) were measured, and 24-hour ambulatory BP monitoring was performed.Overall, there were 62 patients with well-controlled or borderline BP and 83 subjects who did not achieve target BP despite antihypertensive treatment. Patients with suboptimal BP control were characterized by greater PWV (median 9.6/interquartile range: 3.9 vs 8.0/3.3 m/s, P = .002), but borderline lower FMD (8.4% ± 5.0% vs 9.9% ± 5.7%; P = .09) as compared with the group with better BP control. When patients were allocated to subgroups based on the number of current antihypertensive medications, no differences in FMD and NMD were found. However, a significant trend was observed for higher PWV values and decreased proportion of dippers along with the increasing number of drugs. PWV, diabetes, and total cholesterol level, but not FMD or NMD, were explanatory variables for systolic BP in multivariate analysis.Arterial stiffness but not endothelial dysfunction is associated with suboptimal BP control in stable KTRs. Less efficient antihypertensive treatment appears to be caused by inadequate control of nocturnal BP.

Renal denervation of the native kidneys for drug-resistant hypertension after kidney transplantation

There is a strong rationale for renal denervation (RDN) of the native kidneys in kidney transplant recipients with treatment-resistant hypertension. We present a patient with a stable graft function, who underwent RDN for posttransplant therapy-resistant hypertension (24-h ambulatory blood pressure measurement (ABPM) 143/89 mmHg, while compliantly using five different antihypertensive agents). After RDN, BP measurements and orthostatic complaints required withdrawal of two antihypertensive agents and halving a third. At 6 months, ABPM was 134/84 mmHg and allograft function remained unchanged. This case calls for designing well-designed prospective studies on RDN in kidney transplant recipients.

Antihypertensive treatment and resistant hypertension in patients with type 1 diabetes by stages of diabetic nephropathy

OBJECTIVE

To assess blood pressure (BP) control, antihypertensive treatment, and prevalence of resistant hypertension (RH) in patients with type 1 diabetes stratified by stage of diabetic nephropathy.

RESEARCH DESIGN AND METHODS

This cross-sectional study included a nationally representative cohort of patients with type 1 diabetes (N = 3,678) from the Finnish Diabetic Nephropathy Study (FinnDiane). The data were linked to the Drug Prescription Register to obtain purchases of antihypertensive drugs 6 months prior to the baseline visit. The treatment targets were based on the American Diabetes Association guidelines. RH was defined as failure to reach BP target despite the use of three or more antihypertensive drugs of different classes (one of which was a diuretic).

RESULTS

In patients with normal albumin excretion rate, 14.1% were on antihypertensive treatment and 74.6% of them had uncontrolled BP despite treatment. The corresponding figures were 60.5 and 71.2% for the microalbuminuric patients, 90.3 and 80.0% for the macroalbuminuric patients, 88.6 and 88.1% for dialysis, and 91.2 and 90.4% for kidney-transplanted patients. The prevalence of RH was 1.2% in the normoalbuminuric, 4.7% in the microalbuminuric, 28.1% in the macroalbuminuric, 36.6% in the dialysis, and 26.3% in the kidney transplant groups. Age (odds ratio 1.04 [95% CI 1.02-1.05]), estimated glomerular filtration rate (0.97 [0.96-0.97]), waist-to-hip ratio (1.44 [1.15-1.80]), triglycerides (1.19 [1.01-1.40]), microalbuminuria (2.58 [1.43-4.67]), and macroalbuminuria (5.61 [3.20-9.84]) were independently associated with RH.

CONCLUSIONS

The prevalence of uncontrolled hypertension and RH increases with advanced diabetic nephropathy. These data suggest that there is an urgent need for improvement of antihypertensive treatment.