CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Maria Rosa Costanzo, MD* on behalf of the UNLOAD Trial Investigators
* Midwest Heart Foundation, Edward Center for Advanced Heart Failure, Edward Heart Hospital, 4th Floor, 801 S. Washington Street, P.O. Box 3226, Naperville, Illinois 60657 (Email: mcostanzo{at}midwestheart.com).
The UNLOAD trial investigators appreciate the opportunity to reply to Dr. Kazory and colleagues. In response to their assertions, UNLOAD’s subjects reflect "real-world" patients hospitalized with heart failure (HF) patients, 90% of whom have congestion with normal cardiac output and blood pressure (1). UNLOAD’s subjects had advanced HF (mean New York Heart Association [NYHA] functional class = 3.4, Minnesota Living with Heart Failure scores = 70, BNP levels >1,200 pg/ml, 1.5 HF hospitalizations in  12 months). In addition, hypotensive episodes were similar in the 2 groups throughout the follow-up period (p = 0.113) (2).
During hospitalization, 43% of standard care patients lost  4.5 kg, weight loss exceeding that of two-thirds of ADHERE (Acute Decompensated Heart Failure National Registry) subjects. Guidelines caution against the use of high diuretic doses, which can worsen hypotension and renal insufficiency (3). Loop diuretic therapy has been associated with increased morbidity and mortality attributable to deleterious effects on neurohormonal activation, electrolyte balance, and cardiorenal function (4). According to the nephrologic literature: 1) in severe renal insufficiency, maximal natriuretic response occurs with intravenous furosemide doses of 160 to 200 mg; 2) the natriuretic response to maximal loop diuretic doses in NYHA functional class II to IV patients with HF is one-third of that in normal subjects; and 3) in patients with HF, diuretic response is enhanced by giving moderate diuretic doses more frequently, not by giving larger doses (4). Second, the UNLOAD trial was not designed to detect mortality differences; the UNLOAD trial was powered to detect differences in HF rehospitalizations, which, at 90 days, were 50% fewer in the ultrafiltration group. To date, ultrafiltration is the only therapy for decompensated HF shown to have both immediate and sustained benefit. Third, because inotropes increase morbidity and mortality, their use was restricted to patients with poor perfusion (3). Finally, early filter replacement was required in 2 patients because of filter clotting. In the UNLOAD trial, because of either patient selection and/or the use of the Aquadex System guided by cardiologists, mechanical fluid removal was not associated with the complications observed in patients with end-stage renal disease (ESRD) undergoing repeated extracorporeal ultrafiltration. Therapy-related complications should be weighted against the harm of recurrent HF decompensation on both the heart and the kidney.
Tools to determine optimal blood volume in individual patients are critically needed to establish optimal ultrafiltration rates. The mechanisms linking different methods of fluid removal to clinical benefit deserve further investigation. Notably, despite similar fluid loss by ultrafiltration and continuous intravenous diuretics, sustained benefit, as indicated by fewer HF rehospitalizations, occurred only with ultrafiltration. Thus, removal of isotonic ultrafiltrate versus hypotonic urine may be a superior strategy for volume overloaded patients with HF (2). That alternative mechanical fluid-removal services provided by nephrologists might be valuable in volume-overloaded HF patients without renal failure is an interesting and testable hypothesis. The U.S. Renal Data System documents that HF morbidity in patients with ESRD exceeds that of NYHA functional class IV HF patients. Because, by themselves, current fluid-management strategies in ESRD patients may inadequately address cardiorenal interactions, services provided by HF specialists may improve the care of ESRD patients.
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References
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- Adams KF, Fonarow GC, Emerman CL, et al. Characteristics and outcomes of patients hospitalized for heart failure in the United States: rationale, design, and preliminary observations from the first 100,000 cases in the Acute Decompensated Heart Failure National Registry (ADHERE) Am Heart J 2005;149:209-216.[CrossRef][ISI][Medline]
- Costanzo MR, Guglin ME, Saltzberg MT, et al. Ultrafiltration versus intravenous diuretics for patients hospitalized for acute decompensated heart failure J Am Coll Cardiol 2007;49:675-683.[Abstract/Free Full Text]
- Hunt SA, Abraham WT, Chin MH, et al. ACC/AHA 2005 update for the diagnosis and management of chronic heart failure in the adult: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Update the 2001 Guidelines for the Evaluation and Management of Heart Failure) Circulation 2005;112:e154-e235.[Free Full Text]
- Schrier RW. Role of diminished renal function in cardiovascular mortality J Am Coll Cardiol 2006;47:1-8.[Abstract/Free Full Text]
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