Chronic Kidney Disease as a Cardiovascular Risk Factor

Definition and pathophysiology

Chronic kidney disease (CKD) is defined by abnormalities of renal structure or function that persist for more than 3 months and have health implications. Diagnostic criteria include an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73 m², excess urinary albumin excretion—typically a spot urinary albumin-to-creatinine ratio (UACR) above 30 mg/g—or both. The eGFR is generally estimated from serum creatinine using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, incorporating relevant demographic variables; cystatin C may also be used as a filtration marker.

CKD is one of the strongest independent risk factors for cardiovascular disease (CVD) and cardiovascular mortality. Cardiovascular risk rises progressively as kidney function declines and as albuminuria increases. When eGFR falls below approximately 60–75 mL/min/1.73 m², the probability of coronary artery disease (CAD) increases in an approximately linear manner. At an eGFR of 15 mL/min/1.73 m², cardiovascular mortality risk may be as much as three times higher than in individuals without comparable renal impairment.

The cardiovascular burden of CKD extends beyond CAD to peripheral arterial disease, cerebrovascular disease, valvular heart disease, heart failure, atrial fibrillation, and other arrhythmias or conduction abnormalities. CKD also worsens the prognosis of established CVD.

Mechanisms linking CKD to cardiovascular disease

The association is mediated by both traditional and kidney-specific pathways. Diabetes, hypertension, dyslipidaemia, obesity, smoking and increasing age are common risk factors for CKD and CVD. Hypertension and renal disease are bidirectionally related: hypertension accelerates CKD progression, while impaired renal function further increases blood pressure.

Non-traditional cardiovascular mechanisms include:

• Uraemia-associated inflammation

• Oxidative stress

• Vascular dysfunction

• Promotion of vascular calcification

• Albuminuria and proteinuria

• Neurohormonal activation

• Plasma-volume expansion

• Myocardial remodelling and fibrosis

These processes form part of the broader cardiovascular-kidney-metabolic syndrome, in which adiposity, insulin resistance, diabetes, hypertension, CKD and CVD reinforce one another. Dysfunctional adipose tissue contributes to inflammatory and metabolic abnormalities, while CKD promotes vascular and myocardial disease through direct and indirect mechanisms.

The kidney also influences cardiovascular physiology by regulating intravascular volume and neurohormonal systems, particularly the renin–angiotensin–aldosterone system. In heart failure, the interaction between the cardiac and renal axes may produce cardiorenal syndrome. Worsening renal function in the presence of persistent congestion is particularly associated with elevated central venous pressure, which is transmitted to the renal veins and can reduce GFR. Conversely, a rise in creatinine during effective decongestion and overall clinical improvement does not necessarily indicate an adverse outcome.

Classification of CKD

CKD severity is classified by eGFR and albuminuria. The following categories describe the principal eGFR stages:

The stage must be interpreted alongside the cause of kidney disease and the magnitude of albuminuria or proteinuria.

Clinical presentation and symptoms

CKD may remain clinically silent for a prolonged period. Cardiovascular risk is therefore often identified through renal testing rather than symptoms. The clinical expression of cardiovascular disease may also be altered in CKD, and the source material does not provide a detailed catalogue of CKD-specific presentations of myocardial ischaemia.

Symptoms of more advanced renal dysfunction are often nonspecific and include:

• Fatigue and weakness

• Anorexia, altered taste and weight loss

• Mood and cognitive changes

• Sleep disturbance and restless legs

• Peripheral or autonomic neuropathy

• Pruritus

• Asterixis or myoclonus

• Nocturia related to impaired urinary concentration

The full uraemic syndrome may include severe hypertension, metabolic encephalopathy, gastrointestinal bleeding, pericarditis, major electrolyte disturbances—particularly hyperkalaemia—and secondary hyperparathyroidism. Fluid overload and pulmonary oedema may occur.

Cardiovascular manifestations associated with CKD include CAD, peripheral vascular disease, cerebrovascular disease, heart failure, atrial fibrillation, valvular disease and cardiac conduction abnormalities. Renal disease is also associated with increased perioperative risks of myocardial infarction, stroke and worsening heart failure.

Evaluation and physical examination

Assessment should establish:

• Whether CKD is present and has persisted for more than 3 months.

• The eGFR category and degree of albuminuria or proteinuria.

• The presumed cause and rate of renal deterioration.

• The burden of traditional and kidney-specific cardiovascular risk factors.

• The presence of established CVD or heart failure.

• The risk associated with diagnostic procedures, contrast exposure and revascularization.

Important clinical domains include blood pressure, volume status, symptoms of congestion, evidence of peripheral arterial disease, manifestations of heart failure and features of uraemia. In advanced disease, examination may reveal severe hypertension, oedema, pulmonary oedema, pericardial disease, neuropathy or encephalopathy.

A renal ultrasound may assist in distinguishing chronic from more recent renal disease. Bilaterally small kidneys, cortical thinning and kidneys measuring less than 8 cm suggest chronic atrophic disease, although kidney size may remain large in some causes, including diabetic kidney disease.

A cardiovascular assessment should not be limited to coronary symptoms. The increased CKD-associated risk encompasses atherosclerotic, cerebrovascular, peripheral arterial, valvular, myocardial and electrical disease.

Diagnostics

Renal assessment

The principal measurements are:

• eGFR, calculated from calibrated serum creatinine using an estimating equation

• Urinary albumin excretion, preferably expressed as UACR

• Repeated confirmation of impaired renal function or proteinuria over at least 3 months

Serum creatinine alone may underestimate the extent of renal dysfunction in some patients. Both creatinine- and cystatin C-based estimates have limitations, because they do not fully account for renal and extrarenal clearance or, for creatinine, muscle mass.

In patients with diabetes, regular assessment of eGFR and UACR is recommended to detect and stage CKD.

Cardiovascular testing

CKD is associated with a greater burden of atherosclerosis and more advanced plaque features. However, non-invasive cardiovascular testing may be less accurate in CKD than in patients without renal disease. The available source material does not specify particular ECG criteria, echocardiographic findings or stress-testing protocols for CKD-associated cardiovascular risk.

Coronary artery calcium scoring is described as a potentially promising method for risk stratification in CKD, although the source material does not establish a definitive role or provide a specific threshold.

The use of invasive coronary angiography, coronary CT angiography or non-invasive tests requiring nephrotoxic agents requires careful assessment of renal and cardiovascular risk. Contrast exposure should be minimized whenever such testing is necessary.

Contrast-associated acute kidney injury

Contrast-associated acute kidney injury is defined in the supplied material as:

• A serum creatinine rise of 44 µmol/L, equivalent to 0.5 mg/dL, or

• A relative increase of 25% from baseline at 48 hours, or

• A 5–10% increase at 12 hours after contrast administration

It occurs in up to 15% of patients with CKD undergoing radiographic procedures. Most episodes are self-limited, with renal recovery generally occurring within 7 days, but a minority progress to overt renal failure and are associated with greater morbidity and mortality.

Risk reduction requires:

• The lowest necessary total contrast dose

• Low-osmolality or iso-osmolality contrast medium

• Adequate intravenous isotonic hydration before the procedure

• Adequate post-procedure hydration

• Monitoring of renal function after exposure

Biomarkers and laboratory findings

Renal biomarkers

The principal laboratory markers are serum creatinine, eGFR and urinary albumin excretion. UACR above 30 mg/g is a marker of kidney damage, particularly in diabetes.

Albuminuria and proteinuria are not only markers of renal injury but also indicators of cardiovascular and renal progression risk. Heavy proteinuria may persist throughout CKD and is associated with a worse prognosis.

Associated laboratory abnormalities

Advanced CKD may be accompanied by:

• Anaemia, due to iron deficiency, reduced erythropoietin production or other causes

• Hyperkalaemia

• Abnormalities of calcium–phosphate metabolism

• Secondary hyperparathyroidism, related in part to reduced calcitriol

• Elevated inflammatory markers, including C-reactive protein and erythrocyte sedimentation rate

Not all patients with CKD are anaemic; erythrocytosis may occur in selected renal disorders.

Newer biomarkers intended to detect kidney injury before changes in conventional renal-function markers have uncertain clinical utility in the setting of heart failure.

Cardiovascular risk assessment

CKD should be treated as a high-risk cardiovascular state. Risk increases with worsening eGFR and increasing albuminuria, even after adjustment for diabetes, hypertension and other established risk factors.

Risk assessment should include:

• Diabetes and glycaemic status

• Blood pressure and hypertension duration

• Lipid profile

• Smoking status

• Body mass index and obesity

• Albuminuria or proteinuria

• eGFR trajectory

• Established CAD or other atherosclerotic disease

• Heart failure

• Atrial fibrillation and conduction disease

• Peripheral and cerebrovascular disease

• Valvular disease

The greater cardiovascular risk in CKD is accompanied by a higher risk of treatment-related complications, particularly acute kidney injury and bleeding or procedural complications, although the supplied material does not quantify bleeding risk.

Treatment and management

Management requires simultaneous attention to renal progression and cardiovascular risk. A comprehensive strategy includes lifestyle measures, smoking cessation, nutrition, blood-pressure control, lipid management, appropriate renin–angiotensin–aldosterone system blockade and treatment of diabetes.

Lifestyle and integrated care

Risk management should incorporate:

• Smoking cessation

• Healthy nutrition

• Weight management

• Blood-pressure control

• Lipid management

• Diabetes management

• Patient self-management education

• Multidisciplinary, team-based care

Integrated care is particularly emphasized for patients with diabetes, CKD and CVD.

Blood-pressure management

Hypertension is a major modifiable cardiovascular risk factor in CKD. Because hypertension accelerates renal decline and CKD raises blood pressure, treatment is central to prevention of both cardiovascular events and progression of renal disease.

The supplied material does not provide a definitive blood-pressure target or a complete antihypertensive regimen. It notes that the optimal intensity of blood-pressure lowering remains incompletely defined and that intensive lowering in the ACCORD trial did not reduce overall major cardiovascular events or death.

Renin–angiotensin–aldosterone system blockade

Sufficient blockade of the renin–angiotensin–aldosterone system is included in recommended CKD cardiovascular risk management. Certain ACE inhibitors and angiotensin receptor blockers reduce the risk of kidney failure and cardiovascular disease in patients with type 2 diabetes and CKD.

Specific drug names, doses, titration schedules and monitoring thresholds are not provided in the source material.

Lipid management and antiplatelet therapy

Lipid management is a component of high-risk cardiovascular prevention in CKD. In patients with established CVD, aspirin is included in the recommended risk-management strategy.

The source material does not specify lipid-lowering agents, aspirin dose, contraindications or duration of therapy.

Diabetes-directed therapies

In type 2 diabetes with CKD, certain therapies reduce the risk of kidney failure and CVD:

• SGLT2 inhibitors

• Selected GLP-1 receptor agonists

• Finerenone and other nonsteroidal mineralocorticoid receptor antagonist strategies

The source material does not state specific agents, doses, eGFR thresholds, potassium-monitoring protocols or treatment sequencing.

Heart failure and cardiorenal syndrome

Renal dysfunction is common in heart failure and is an established marker of poor outcome. Management must interpret changes in renal function in the context of congestion, perfusion and overall clinical response. Worsening renal indices with persistent congestion are concerning, whereas a modest deterioration during successful decongestion may reflect effective treatment rather than treatment failure.

The supplied material does not provide specific heart-failure drug doses or a complete treatment algorithm for patients with CKD.

Coronary artery disease and revascularization

CKD is associated with more extensive atherosclerosis and advanced plaque morphology, but diagnostic testing and treatment decisions are complicated by lower test accuracy, contrast-related renal injury and increased procedural risk.

Before invasive coronary angiography, coronary CT angiography or contrast-dependent testing, the balance between anticipated diagnostic or therapeutic benefit and renal injury should be assessed carefully. Contrast minimization and hydration are important preventive measures.

CKD increases the risks of both coronary artery bypass grafting and percutaneous coronary intervention. In advanced CKD—defined in the cited trial population as eGFR below 30 mL/min/1.73 m² or dialysis—an invasive strategy with angiography and PCI did not reduce death or non-fatal myocardial infarction compared with conservative management in patients with stable coronary disease and moderate or severe ischaemia.

Comparative observational evidence is mixed:

• In a propensity-matched analysis of CKD patients, PCI using second-generation drug-eluting stents was associated with lower 30-day risks of death, stroke and repeat revascularization than CABG.

• PCI was associated with more repeat revascularization during long-term follow-up.

• Among patients receiving dialysis, findings favoured CABG over PCI.

• A meta-analysis of registries found lower rates of death, myocardial infarction and repeat revascularization with CABG than PCI in patients with eGFR below 60 mL/min/1.73 m².

Large randomized trials comparing revascularization strategies specifically in CKD remain lacking. Decisions should therefore be individualized according to coronary anatomy, symptoms, ischaemic burden, renal stage, dialysis status, procedural risk and expected benefit.

Perioperative and procedural management

Renal disease substantially increases perioperative cardiovascular risk. Patients undergoing non-cardiac surgery are at increased risk of myocardial infarction, stroke and worsening heart failure.

Patients with cardiac disease are also vulnerable to postoperative acute kidney injury, especially when haemodynamic status is compromised by fluid shifts or blood loss, or when cardioactive medications are withdrawn or continued inappropriately. Risk factors include:

• Heart failure, particularly decompensated disease

• Hypertension

• Cardioactive medications

• Older age

• Emergency surgery

• Intraperitoneal surgery

• Pre-existing renal insufficiency or elevated creatinine

• CKD

• Diabetes

The combination of low cardiac output, elevated venous pressure and iodinated contrast exposure are frequent mechanisms of acute kidney injury in hospitalized cardiac patients. Prevention and management include preservation of adequate intravascular volume for renal perfusion, use of vasopressors when required, avoidance of unnecessary contrast and postoperative renal-function surveillance.

Guideline recommendations

The supplied guidance supports the following principles:

• CKD should be recognized as a major cardiovascular risk condition.

• Patients with diabetes should undergo regular CKD screening and staging using eGFR and UACR.

• Traditional risk factors—especially hypertension, dyslipidaemia, diabetes, smoking and obesity—should be treated intensively.

• Lifestyle intervention, smoking cessation, nutritional management and patient self-management education should be incorporated into care.

• Renin–angiotensin–aldosterone system blockade should be used appropriately.

• Lipid management is required, and aspirin should be used in patients with established CVD where appropriate.

• SGLT2 inhibitors, selected GLP-1 receptor agonists and nonsteroidal mineralocorticoid receptor antagonists are newer therapies that can reduce cardiovascular and renal risk in relevant CKD and metabolic populations.

• Contrast procedures require careful risk–benefit assessment, minimal contrast volume, low- or iso-osmolality contrast and adequate intravenous isotonic hydration.

• Patients with advanced CKD and stable coronary disease should not automatically undergo an invasive strategy solely because stress testing demonstrates moderate or severe ischaemia.

• Multidisciplinary, integrated care is particularly valuable in patients with overlapping diabetes, CKD and CVD.

Specific drug doses, blood-pressure targets and detailed class-of-recommendation tables are not provided in the source material.

Prognosis and follow-up

CKD is associated with high cardiovascular mortality, and most patients with CKD die from CVD before reaching kidney failure. Cardiovascular risk increases progressively as eGFR declines and albuminuria rises. CKD also worsens outcomes in patients with established CVD and increases the risk of complications after surgery, contrast exposure, PCI and CABG.

Follow-up should monitor:

• eGFR and its rate of decline

• UACR or proteinuria

• Blood pressure

• Glycaemic status

• Lipids

• Potassium and other relevant electrolytes

• Volume status and symptoms of heart failure

• Cardiovascular symptoms and functional status

• Medication tolerance and renal effects

• Exposure to nephrotoxic drugs or procedures

In advanced CKD, preparation for renal replacement therapy should begin before kidney failure develops. Discussions regarding dialysis and transplantation are appropriate when eGFR is approximately 15–20 mL/min/1.73 m², with timing individualized to the clinical course.

After cardiac transplantation, chronic renal failure—defined in the supplied material as GFR of 29 mL/min/1.73 m² or less or development of end-stage renal disease—has a reported cumulative incidence of 10.9% at 5 years. Calcineurin-inhibitor nephrotoxicity is a major contributor, with age, diabetes, hypertension, sex and hepatitis C infection also identified as risk factors. Renal transplantation can substantially mitigate the high mortality associated with end-stage renal disease after heart transplantation.