Non-high-output cardiac failure in patients undergoing hemodialysis through an arteriovenous shunt

Background: Hemodialysis-related heart failure has been considered to be associated with excessive blood flow through the arteriovenous (AV) shunt used for vascular access. However, some patients undergoing dialysis have heart failure in the absence of an increase in cardiac output (CO) related to shunt blood-flow loading because the loading cannot be compensated for by increasing CO. This condition may be challenging to manage ; thus, early diagnosis is important. Methods and Results: Twelve patients (mean age, 71 years ; 9 men) with end-stage renal disease, dialysis-related heart failure, a high brain natriuretic peptide (BNP) level, and a mean New York Heart Association (NYHA) class of II underwent AV shunt closure. Their cardiac index (CI), pre- and post-dialysis BNP levels, and several cardiac variables were assessed pre- and postoperatively. All patients achieved relief of heart failure symptoms and a reduction in NYHA class after AV closure, but six patients had a postoperative increase in CI (the "non-high-output" cardiac failure group), whereas the other six had a decrease in CI (the "high-output" cardiac failure group). The high-output patients had greater improvements in BNP levels and most cardiac variables compared to the non-high-output group ; therefore, the heart failure in the non-high-output patients was considered more serious than that in the high-output group. Conclusions: The selection of effective strategies for treating dialysis-related heart failure may depend partly on identifying which patients have non-high-output failure. Such identification requires serial measurements of BNP levels and evaluations of cardiac variables other than the ejection fraction