Emerging therapies for heart failure: renal mechanisms and effects. Heart Fail Rev. 2012;17:1-16. [PMID: 20803357 DOI: 10.1007/s10741-010-9191-5]

Extracorporeal Isolated Ultrafiltration for Management of Congestion in Heart Failure and Cardiorenal Syndrome

Acute decompensated heart failure has the highest rate of hospital readmission among all medical conditions and portends a significant financial burden on health care system. Congestion, the hallmark of acute decompensated heart failure, represents the primary reason for hospitalization and the driver of adverse outcomes in these patients. Although diuretic-based medical regimens remain the mainstay of management of acute decompensated heart failure, they often show suboptimal efficacy and safety profiles in this setting. Mechanical extraction of excess fluid through extracorporeal ultrafiltration therapy has been proposed as a mechanistically relevant option in this setting. The advent of simplified, portable, and user-friendly devices that are dedicated to ultrafiltration therapy for these patients has renewed the interest in this therapeutic modality. In this article, we provide a brief overview of the initial mechanistic studies followed by the key clinical findings of the most recent landmark trials. The shortcomings of these studies are discussed in detail because not only do they provide the appropriate context in which the results are to be interpreted, but more importantly they also highlight the existing knowledge gaps that need to be addressed in future studies. Finally, selected practical and conceptual considerations and controversies are reviewed with regard to evidence-based ultrafiltration therapy.

Peritoneal dialysis for chronic cardiorenal syndrome: Lessons learned from ultrafiltration trials

The current models of cardiorenal syndrome (CRS) are mainly based on a cardiocentric approach; they assume that worsening renal function is an adverse consequence of the decline in cardiac function rather than a separate and independent pathologic phenomenon. If this assumption were true, then mechanical extraction of fluid (i.e., ultrafiltration therapy) would be expected to portend positive impact on renal hemodynamics and function through improvement in cardio-circulatory physiology and reduction in neurohormonal activation. However, currently available ultrafiltration trials, whether in acute heart failure (AHF) or in CRS, have so far failed to show any improvement in renal function; they have reported no impact or even observed adverse renal outcomes in this setting. Moreover, the presence or absence of renal dysfunction seems to affect the overall safety and efficacy of ultrafiltration therapy in AHF. This manuscript briefly reviews cardiorenal physiology in AHF and concludes that therapeutic options for CRS should not only target cardio-circulatory status of the patients, but they need to also have the ability of addressing the adverse homeostatic consequences of the associated decline in renal function. Peritoneal dialysis (PD) can be such an option for the chronic cases of CRS as it has been shown to provide efficient intracorporeal ultrafiltration and sodium extraction in volume overloaded patients while concurrently correcting the metabolic consequences of diminished renal function. Currently available trials on PD in heart failure have shown the safety and efficacy of this therapeutic modality for patients with chronic CRS and suggest that it could represent a pathophysiologically and conceptually relevant option in this setting.

Cardiorenal syndrome: ultrafiltration therapy for heart failure--trials and tribulations

Heart failure remains the leading cause of hospitalization in older patients and is considered a growing public health problem with a significant financial burden on the health care system. The suboptimal efficacy and safety profile of diuretic-based therapeutic regimens coupled with unsatisfactory results of the studies on novel pharmacologic agents have positioned ultrafiltration on the forefront as an appealing therapeutic option for patients with acute decompensated heart failure (ADHF). In recent years, substantial interest in the use of ultrafiltration has been generated due to the advent of dedicated portable devices and promising results of trials focusing both on mechanistic and clinical aspects of this therapeutic modality. This article briefly reviews the proposed benefits of ultrafiltration therapy in the setting of ADHF and summarizes the major findings of the currently available studies in this field. The results of more recent trials on cardiorenal syndrome that present a counterpoint to previous observations and highlight certain limitations of ultrafiltration therapy are then discussed, followed by identification of major challenges and unanswered questions that could potentially hinder its more widespread use. Future studies are warranted to shed light on less well characterized aspects of ultrafiltration therapy and to further define its role in ADHF and cardiorenal syndrome.