Chronic kidney disease (CKD) patients have a higher risk of heart disease, disorders, and dysfunction—a connection formerly not well understood until a recent study. Performed by a group of researchers and physicians at Brigham and Women’s Hospital in Boston, Massachusetts and published in Circulation, the study showed that defects in the heart’s small blood vessels—or coronary microvascular dysfunction (MVD)—are to blame.* In addition, this study is the first of its kind to identify pathological alterations linking kidney disease to progressive heart disease.

Background information

In healthy individuals, the small blood vessels of the heart muscle (myocardium) feed oxygen and nutrients to the heart as it pumps. In patients with MVD, this blood flow is significantly reduced, thus prompting the need to study a possible relation between MVD, abnormal renal function, and impairment and malfunctions of the cardiovascular system.

Research and investigation details

The 352 patients studied had the following characteristics:

• a median age of 65 years old;
• 63% female and 37% male; and
• 22% black,

Their cardiovascular and kidney functions were followed for a median of 4.4 years. The examinations performed on these patients included cardiac stress positron emission tomography (PET), echocardiogram, analysis of estimated glomerular filtration rate (eGFR), and other assessments.

eGFR is a blood test to determine your GFR, or glomerular filtration rate, in order to establish your level of renal function and stage of CKD. The test measures the amount of creatinine in the blood.

Results and conclusions

A statistical computer program processed the results of the cardiovascular system functions and kidney tests to reveal the relationship between reduced renal function and MVD. MVD was a major predictor of abnormal mechanics of the left ventricle—the heart’s main pumping chamber.

Moreover, the pathological changes in these small blood vessels were an important predictor of clinical risk for serious heart problems, or adverse cardiovascular outcomes. The microvascular impairments send a signal to the left ventricle causing its remodeling from a physiological to a pathological state. These changes increase the risk of heart failure and death in patients with CKD.

The study’s authors concluded that “our study is clinically important because it […] suggests coronary microvascular dysfunction as a target for novel therapeutic approaches to reduce cardiovascular disease risk.” They also believe that this new data “may be helpful in the design of future clinical trials in patients with CKD.”

More information is available in the press release by the University of Alabama at Birmingham—the hospital of the primary researcher involved in the study.

*Bajaj, N., Singh, A., Zhou, W., Gupta, A., et al. (2019, Nov. 29). “Coronary Microvascular Dysfunction, Left Ventricular Remodeling, and Clinical Outcomes in Patients With Chronic Kidney Impairment.” Circulation.