Extracorporeal ultrafiltration for heart failure: focus on organ cross talk and clinical trials

Cardiorenal syndrome: Multi-organ dysfunction involving the heart, kidney and vasculature

Cardiorenal syndrome (CRS) is a multi-organ disease, encompassing heart, kidney and vascular system dysfunction. CRS is a worldwide problem, with high morbidity, mortality, and inflicts a significant burden on the health care system. The pathophysiology is complex, involving interactions between neurohormones, inflammatory processes, oxidative stress and metabolic derangements. Therapies remain inadequate, mainly comprising symptomatic care with minimal prospect of full recovery. Challenges include limiting the contradictory effects of multi-organ targeted drug prescriptions and continuous monitoring of volume overload. Novel strategies such as multi-organ transplantation and innovative dialysis modalities have been considered but lack evidence in the CRS context. The adjunct use of pharmaceuticals targeting alternative pathways showing positive results in preclinical models also warrants further validation in the clinic. In recent years, studies have identified the involvement of gut dysbiosis, uraemic toxin accumulation, sphingolipid imbalance and other unconventional contributors, which has encouraged a shift in the paradigm of CRS therapy.

Incidence, Mortality and Positive Predictive Value of Type 1 Cardiorenal Syndrome in Acute Coronary Syndrome

OBJECTIVES

To determine whether the risk of cardiovascular mortality associated with cardiorenal syndrome subtype 1 (CRS1) in patients who were hospitalized for acute coronary syndrome (ACS) was greater than the expected risk based on the sum of its components, to estimate the predictive value of CRS1, and to determine whether the severity of CRS1 worsens the prognosis.

METHODS

Follow-up study of 1912 incident cases of ACS for 1 year after discharge. Cox regression models were estimated with time to event (in-hospital death, and readmission or death during the first year after discharge) as the dependent variable.

RESULTS

The incidence of CRS1 was 9.2/1000 person-days of hospitalization (95% CI = 8.1-10.5), but these patients accounted for 56.6% (95% CI = 47.4-65.) of all mortality. The positive predictive value of CRS1 was 29.6% (95% CI = 23.9-36.0) for in-hospital death, and 51.4% (95% CI = 44.8-58.0) for readmission or death after discharge. The risk of in-hospital death from CRS1 (RR = 18.3; 95% CI = 6.3-53.2) was greater than the sum of risks associated with either acute heart failure (RR = 7.6; 95% CI = 1.8-31.8) or acute kidney injury (RR = 2.8; 95% CI = 0.9-8.8). The risk of events associated with CRS1 also increased with syndrome severity, reaching a RR of 10.6 (95% CI = 6.2-18.1) for in-hospital death at the highest severity level.

CONCLUSIONS

The effect of CRS1 on in-hospital mortality is greater than the sum of the effects associated with each of its components, and it increases with the severity of the syndrome. CRS1 accounted for more than half of all mortality, and its positive predictive value approached 30% in-hospital and 50% after discharge.

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.

[Treatment of acute renal failure in Germany: Analysis of current practice]

BACKGROUND AND OBJECTIVES

There are currently no reliable data on the differential use of renal replacement therapy (RRT) options for critically ill patients with acute renal failure in Germany.

PATIENTS AND METHODS

A questionnaire-based survey was delivered to 2265 German intensive care units. The questionnaire contained 19 questions regarding RRT.

RESULTS

A total of 423 German intensive care units participated in the survey. The offered modalities of RRT varied significantly: the smaller the facility, the fewer different RRT options were available. Intermittent dialysis procedures were available in only 35% of hospitals with up to 400 beds. In university hospitals, hemodynamically unstable patients were exclusively treated by continuous RRT, whereas in hospitals with up to 400 beds, intermittent RRT was also used. In addition, treatment practice was also dependent on the specialization of the treating physicians: Isolated acute renal failure was treated more often intermittently by nephrologists compared to anesthesiologists (79.7 vs. 43.3%). Nephrologists also used extracorporeal RRT more often in cardiorenal syndrome (54.3 vs. 35.8%), whereas anesthesiologists preferred them in sepsis (37.3 vs. 23.1%). The choice of anticoagulant varied as well: Hospitals with up to 400 beds offered regional citrate anticoagulation in only 50% compared to 90% of university hospitals.

CONCLUSIONS

Currently, RRT treatment in acute renal failure on German intensive care units seems to be dependent on the size, local structures, and education of the intensivists rather than patient needs. Our results demonstrate the necessity to establish cross-disciplinary standards for the treatment of acute renal failure in German intensive care units.