From the Guidelines
The pathophysiology of hypertension in chronic kidney disease (CKD) involves complex interactions between kidney dysfunction and cardiovascular disease, with hypertension being both a cause and a consequence of CKD. The primary mechanism involves an imbalance of vasoactive substances, with increased vasoconstrictors (renin-angiotensin-aldosterone system, sympathetic nervous system, endothelin) and decreased vasodilators (prostaglandins, nitric oxide) 1. In CKD patients, these hemodynamic changes are superimposed on already compromised kidney function, accelerating decline in glomerular filtration rate. Additionally, systemic inflammation from both conditions exacerbates kidney injury through inflammatory cytokines and oxidative stress. The combination of reduced effective arterial blood volume, intense renal vasoconstriction, and inflammatory injury leads to progressive deterioration of kidney function, creating a vicious cycle where worsening kidney function further compromises cardiovascular health and vice versa. Key factors contributing to the development of hypertension in CKD include long-term caloric intake in excess of energy expenditures, chronic supraphysiological intake of dietary sodium, excessive alcohol consumption, and psychosocial stressors 1. Management of hypertension in CKD is crucial to prevent further kidney functional decline and reduce the risk of cardiovascular disease, with a recommended blood pressure target of <130/80 mmHg for all patients with CKD 1. Lifestyle modifications, such as weight loss, physical activity, and smoking cessation, are also important in managing hypertension in CKD, although data supporting these interventions are mostly observational and extrapolated from non-CKD samples 1. Dietary therapies, including reduced salt intake and dietary strategies to manage dyslipidemia, are also recommended for persons with early stages of CKD 1. Overall, the management of hypertension in CKD requires a comprehensive approach that addresses both kidney dysfunction and cardiovascular disease, with the goal of reducing morbidity, mortality, and improving quality of life. Key interventions include:
- Blood pressure control with a target of <130/80 mmHg
- Lifestyle modifications, such as weight loss, physical activity, and smoking cessation
- Dietary therapies, including reduced salt intake and dietary strategies to manage dyslipidemia
- Pharmacologic modulators of the renin-angiotensin-aldosterone-kinin system, such as ACE inhibitors or ARBs, for patients with albuminuria or reduced kidney function 1.
From the Research
Pathophysiology of Hypertension in Chronic Kidney Disease (CKD)
The pathophysiology of hypertension in CKD is complex and involves the interplay of multiple factors. Some of the key factors include:
- Salt and water retention, leading to extracellular volume expansion 2, 3, 4
- Sympathetic nervous system overactivity 2, 3, 4
- Renin-angiotensin-aldosterone system activation 2, 3, 4, 5, 6
- Endothelial dysfunction 2, 3, 4, 6
- Oxidative stress 4, 6
- Vascular remodeling 4
- Disorders of calcium metabolism and parathyroid hormone secretion 6
- Vascular calcification and increased arterial stiffness 6
Mechanisms Contributing to Hypertension in CKD
The mechanisms contributing to hypertension in CKD are multifaceted and involve:
- Reduced number of functioning nephrons 3
- Sodium retention and volume expansion 3, 4
- Upregulation of the sympathetic nervous system 3, 4
- Hormonal factors such as upregulation of the renin-angiotensin-aldosterone system 3, 4
- Endothelial dysfunction 3, 4
Impact of Hypertension on CKD Progression
Poorly controlled hypertension can accelerate the progression to end-stage kidney disease 3. The control of high blood pressure via therapeutic interventions is crucial to reduce the cardiovascular burden in kidney disease 4. Renin-angiotensin system blockers, such as angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, are the main drugs used to achieve this goal 5.