Did you know chronic kidney disease (CKD) is a risk factor for having a stroke? People with CKD are at higher risk for both subtypes of stroke (hemorrhagic and ischemic). With CKD becoming more prevalent worldwide, the chances of having a stroke are also increasing. Learn more about what mechanisms may put patients at increased risk and what may be done to help prevent strokes in CKD patients.* 

What Are Stroke Risk Factors for CKD Patients?

In addition to conventional heart disease risk factors, studies have found specific risk factors in CKD patients and stroke. They include:

• Reduction in estimated glomerular filtration rate (eGFR), which is a calculation that estimates overall kidney function
• Greater degree of albuminuria (protein in the urine)
• Asian and/or West African descent with markedly increased risk for those with stage 3 (or higher) CKD
• Patients with end-stage kidney disease (ESKD) on dialysis are at higher risk for stroke than those with predialysis CKD

Moreover, CKD patients who have a stroke are at greater risk for: 

• Stroke morbidity and mortality 
• Neurological deficit following ischemic stroke
• Poor functional outcomes following a stroke 

What Effect Does Kidney Disease Have on the Brain? 

The kidney and the brain share similar microvasculature (small blood vessels) and vasoregulation (regulation of blood vessel tension and blood flow). This means they share susceptibility to vascular dysfunction.

Research has supported this theory in CKD patients with findings that include:

• Decreased eGFR associated with a decreased cerebral blood flow (CBF) and cerebral autoregulation of the blood vessels
• Lower cerebral oxygenation saturation (the amount of oxygen traveling through a person’s red blood cells) in dialysis patients than those with predialysis CKD
• Decreased eGFR was related to increased arterial diameter, circumferential wall stress, and carotid artery stiffness, which may have a negative effect on the cerebral vasculature

Why Is Intracranial Imaging Needed for Kidney Disease?

While imaging is not currently a standard of care prior to dialysis, taking intracranial imaging may help physicians to make better-informed recommendations on:

• Dialysis modality
• Individualized prescriptions 
• Ultrafiltration goals 
• Intradialytic blood pressure goals when starting dialysis

Each of these can be optimized to help minimize stroke risk in ESKD on dialysis patients. For non-dialysis patients, imaging may help assess overall stroke risk and progression. 

How Can TCD Imaging Ultrasound be Useful?

While there are multiple noninvasive intracranial imaging options to help identify patients at risk for stroke, a TCD ultrasound may be a practical and preferred option, as it includes intracranial vessel imaging and can be done at a patient’s bedside. Moreover, TCD ultrasounds are able to monitor cerebrovascular hemodynamics, such as CBF, resistance to flow, and vessel autoregulation.

While the benefits to both dialysis and predialysis CKD patients are evident, TCD ultrasounds still have their limitations, including:

• Ultrasound operator technique and experience using the equipment
• Lack of spatial resolution in images to identify CBF

Improving Stroke Risk in CKD Patients

Further research is needed to help identify CKD patients at low and high risk for strokes. More information on the benefits of reducing albuminuria and eGFR in CKD patients related to stroke would also be helpful. 

With the risk for stroke in CKD patients rising, specific measures for this population need to be put in place now. Developing a noninvasive screening process and tools for prevention, including imaging, are urgently needed to minimize stroke-related morbidity and mortality in this population. 

*Ghoshal, S., & Freedman, B. (2019). Mechanisms of Stroke in Patients with Chronic Kidney Disease. FullText – American Journal of Nephrology 2019, Vol. 50, No. 4 – Karger Publishers. https://www.karger.com/Article/FullText/502446