Bridging the gap between health problems of the heart and kidneys continues to be a talking point amongst specialists. Across both fields, there is clear evidence and recognition that kidney function can affect cardiac health. Kidney patients are vulnerable to a higher level of cardiovascular events as a risk factor and vice versa. Over half of all heart failure patients have moderate or severe chronic kidney disease. Both conditions are connected to similar risk factors, including obesity, diabetes, hypertension, age, and family medical history. It has long been assumed that it is these shared risk factors that are the cause of the relationship between kidney and heart disease.
The heart and the kidneys are two of the body’s vital organs with a very close working relationship. While the heart functions to provide the body with a sufficient supply of oxygenated blood, the kidneys work to filter the blood, extract waste products, and maintain normal body conditions.
Kidney dysfunction can lead to increased blood pressure, which if left untreated may result in constriction of the heart vessels. High blood pressure can also exert strain on the veins and arteries surrounding the kidney, smaller vessels to the filters, and the filters themselves. Kidneys work to control blood mineral and salt levels, including potassium, chloride, and sodium, along with many others. An improper balance of these electrolytes may cause abnormalities in heartbeat and may lead to more serious conditions, such as arrhythmia. The ratios of calcium and phosphate levels in blood are also affected as a result of chronic kidney disease. An excess of calcium deposits may lead to plaque build-up in the heart and surrounding blood vessels and restrict blood flow to other organs.
Cardiorenal syndrome is the general term used to describe the overlap between conditions involving both kidney and heart dysfunction. Here are some of the more serious problems related to both heart and kidney functions:
Congestive heart failure is the condition in which the heart is unable to pump blood with enough pressure and volume around the body. The condition is becoming more common in the west, especially among older people. It can lead to kidney disease, likely as a result of the decrease in renal blood flow caused by the weakened heart muscle. Having high blood pressure is a major contributing risk factor for heart failure, and accordingly for kidney failure too.
Chronic kidney disease is the gradual loss of function of the kidneys over time, typically caused by problems from other illnesses such as hypertension or diabetes. Patients with chronic kidney disease have a higher risk of cardiovascular problems, which increase as kidney function decreases. Heart disease is the biggest contributor to mortality of patients with kidney disease. Statins, usually used to treat high cholesterol levels and lower risk of heart attacks, have been shown to decrease cardiovascular events in patients with the disease as well as slow rate of function decline of kidneys. In a meta-analysis looking at statins in clinical trials, fatal cardiovascular events were decreased by almost 20%.
End stage renal disease is the point at which the kidneys can no longer function as needed, meaning transplant or dialysis are the only solutions. Patients with the disease carry a much higher risk of cardiovascular disease related fatality.
To best manage patients with these conditions, heart and kidney specialists need to understand and learn from each other’s expertise. With many crossover points, cardio-renal diseases require collaboration between both sides to improve patient care and strive for best outcomes.
To showcase this need for collaboration, OUP has highlighted a selection of the latest research on cardio-renal issues and treatment published in the European Renal Association – European Dialysis and Transplant Association (ERA-EDTA) and the European Society of Cardiology (ESC) journals.
“Cardiovascular disease is highly prevalent in patients with chronic kidney disease,” said Professor Thomas Lüscher, editor-in-chief of the European Heart Journal. “Sudden cardiac death is common among patients in the first 90 days of dialysis and it is hoped this collaboration will allow practitioners from both disciplines further their knowledge and research.”
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