Low Hemoglobin, Low SEVR Linked in Chronic Kidney Disease
Researchers used pulse wave analysis to measure subendocardial viability ratio, a measure of myocardial perfusion, and its association with hemoglobin.
Subendocardial viability ratio (SEVR) is independently associated with hemoglobin in patients who have chronic kidney disease but are not on dialysis, researchers reported online in Clinical Nephrology. Patients with lower hemoglobin levels have lower SEVR, a non-invasive measure of myocardial perfusion.
Robert Ekart, MD, and colleagues at University Medical Centre Maribor in Slovenia, used pulse wave analysis (PWA) to measure SEVR in a cohort of 91 non-dialysis CKD patients (mean age 60.2 years). The researchers examined the associations between PWA hemodynamic parameters, 24-hour ambulatory blood pressure (BP) measurements, and laboratory variables, including hemoglobin, troponin I, NT-proBNP, and hs-C-reactive protein. They divided patients into 2 groups according to the median hemoglobin value (13.3 g/dL).
In multivariate regression analysis, the researchers found that SEVR was significantly associated with hemoglobin and troponin I. Patients with hemoglobin values below the median had significantly lower SEVR, estimated glomerular filtration rate, and office diastolic BP, and significantly higher serum creatinine, cystatin C, NT-proBNP, and 24-hour ambulatory systolic BP.
“Blood flow in the subendocardium stops during ventricular contraction,” Dr Ekart and his colleagues explained. “As a result, most myocardial perfusion occurs during diastole when the subendocardial coronary vessels are open and under lower pressure. The amount of hemoglobin and its saturation are the primary determinants of how much oxygen is contained within the arterial blood. These facts could explain the association between SEVR and hemoglobin in our patients.”
The authors noted that the strength of their study was the enrollment of patients with different CKD stages and the main limitation was the small sample size.
Ekart R, Bevc S, Hojs N, et al. Relationship between subendocardial viability ratio and hemoglobin in patients with chronic kidney disease. Clin Nephrol 2017; published online ahead of print. doi: 10.5414/CNP88FX06