Continuous infusion or bolus injection of loop diuretics for patients admitted for severe acute heart failure: is one strategy better than the other?

Intravenous loop diuretics are an essential part of acute heart failure management; however, data to guide their use is sparse. Our aim was to compare continuous intravenous infusion of loop diuretics with intravenous bolus administration in terms of efficacy and adverse events in patients admitted with severe acute heart failure.

Over a period of three years, 110 patients were admitted to our cardiac intensive care unit with acute heart failure. Clinical, laboratory and prognostic parameters were compared according to the diuretic strategy used and mortality and readmission for acute heart failure during follow-up were analyzed.

Previous medical history was similar in the two groups. At admission, the continuous infusion group met criteria for worse prognosis: lower systolic blood pressure (p=0.011), more severe renal injury (p=0.008), lower left ventricular ejection fraction (p=0.016) and higher incidence of restrictive pattern of diastolic dysfunction (p=0.032). They were more often treated with vasopressors (p=0.003), inotropes (p=0.010), renal support therapy (p=0.003) and non-invasive ventilation (p<0.001). They had longer hospitalizations (p=0.014) and a higher incidence of cardiorenal syndrome (p=0.009); however, at discharge, there were no differences in renal function between the groups. In-hospital mortality was similar, and during follow-up there were no differences in mortality or readmission for acute heart failure.

Continuous infusion was preferred in patients presenting with worse clinical status, in whom renal dysfunction was transiently worse. However, in-hospital mortality and creatinine at discharge were similar. Continuous infusion thus appears to counteract the initial dire prognosis of more unstable patients.