Anemic individuals with heart failure with preserved ejection fraction displayed unique pathophysiological features that led to reduced exercise capacity.
New research findings show that reduced exercise capacity is a contributor to worse outcomes among patients with heart failure with preserved ejection fraction (HFpEF) and anemia, compared to those without anemia.
Due to lack of data regarding how anemia contributes to reduced exercise capacity in patients with HFpEF, researchers conducted a study that depicted exercise capacity, cardiovascular and ventilatory reserve, and the oxygen (O2) pathway in individuals with anemia and HFpEF.
Exercise intolerance is reported to be a leading factor in the development of HFpEF. Researchers have found that multiple cardiac and extra-cardiac reserve limitations have contributed to the reduction of exercise capacity, compared to single impairment of the left ventricular diastolic dysfunction, which was the main contributor to HFpEF.
Researchers found that anemia is common among individuals with HFpEF and relates to worsened clinical outcomes. This is because anemia causes a lower-than-normal amount of healthy red blood cells, leading to feeling tired or weak due to the lack of oxygen. However, anemia in HFpEF is reported to be caused by “iron deficiency, chronic kidney disease (or cardiorenal syndrome), use of antiplatelet or anticoagulant agents, chronic inflammation, or poor nutritional status,” according to the study authors.
To assess whether exercise capacity could be reduced in individuals with HFpEF and anemia compared to those without anemia, the researchers used the rate of oxygen consumption during peak exercise and the quantification of oxygen transport, along with how the pathways are being utilized.
The researchers included 238 individuals with HFpEF and 248 dyspneic individuals without heart failure. The diagnoses of HFpEF were made using the Heart Failure Association Pre-Test assessment, echocardiography, and natriuretic peptide, functional testing, and a final etiology algorithm. Individuals with HFpEF were placed in 2 groups based on the prevalence of their anemia.
The study noted that exercise stress echocardiography was conducted with the 248 patients who did not have heart failure. Performed by sonographers, the echocardiography included an ergometry exercise that began at 20W for 5 minutes, with increments of 3 minutes until the individuals showed signs of exhaustion. Results were recorded prior to the exercise and a simultaneous expired gas analysis was conducted to measure oxygen consumption and carbon dioxide production.
“A subset of participants underwent clinically indicated right heart catheterization at rest and during supine ergometry exercise as confirmatory testing. Exercise right heart catheterization was considered by clinicians when the results of exercise echocardiography were equivocal. RAP, pulmonary artery pressures, and PCWP were measured at end-expiration (mean of ≥ 3 beats) using a 7 Fr fluid-filled catheter, as previously described,” said the study authors.
The study authors noted that of the 486 individuals included in the study, 58 were diagnosed due to right heart catheterization and anemia was 47% more present in individuals with HFpEF. Regarding the results from the echocardiography, the exercise capacity was more impaired in individuals with anemia that also had HFpEF, compared to other groups.
The researchers concluded that anemic HFpEH individuals had “worse nutritional status, lower renal function, and greater left heart remodeling and plasma volume expansion” compared to individuals that did not have anemia. Poor exercise capacity was due to impaired arterial oxygendelivery that impacted the peripheral oxygenextraction and utilization. However, the study authors note that further research could aid the treatment of anemic HFpEF.
Contributions of anemia to exercise intolerance in heart failure with preserved ejection fraction–An exercise stress echocardiographic study. Science Direct. News release. October 2023. Accessed October 26, 2023. https://www.sciencedirect.com/science/article/pii/S2352906723000866?via%3Dihub.