Efficacy of Intravenous Furosemide Versus a Novel, pH-Neutral Furosemide Formulation Administered Subcutaneously in Outpatients With Worsening Heart Failure.

OBJECTIVES: This study sought to determine the efficacy and safety of a novel, pH-neutral formulation of furosemide administered subcutaneously (SC) for treatment of acute decompensated heart failure (HF). BACKGROUND: Congestion requiring intravenous (IV) administration of a diuretic agent is the main reason patients with HF present for acute medical care. METHODS: Outpatients presenting with decompensated HF were randomized to receive a single SC or IV dose of furosemide. Primary outcome was 6-h urine output, and secondary outcomes were weight change, natriuresis, and adverse events. RESULTS: Forty-one patients were randomized: 19 were treated with IV (mean dose: 123 ± 47 mg) and 21 with SC furosemide (fixed dose of 80 mg over 5 h). The 6-h urine output in the IV group was not significantly different from that in the SC furosemide group (median IV: 1,425 ml; interquartile range [IQR]: 1,075 to 1,950 ml; vs. median SC: 1,350 ml; IQR: 900 to 1,900 ml; p = 0.84). Additionally, mean weight loss was not significantly different (-1.5 ± 1.1 kg in the IV group vs. -1.5 ± 1.2 kg in the SC group; p = 0.95). Hourly urine output was significantly higher in the IV group at hour 2 (425 ml in the IV group vs. 250 ml in the SC group; p = 0.02) and higher in the SC group at hour 6 (125 ml, IV group vs. 325 ml, SC group; p = 0.005). Natriuresis was higher in the SC group (IV: 7.3 ± 35.3 mEq/l vs. SC: 32.8 ± 43.6 mEq/l; p = 0.05). There was no worsening renal function, ototoxicity, or skin irritation with either formulation. Thirty-day hospitalization rates were similar. CONCLUSIONS: In this phase II trial, we did not identify significant differences between urine output obtained with pH-neutral furosemide administered SC and that obtained by IV. This method of decongestion may allow treatment at home and reduced HF resources and warrants further investigation. (Sub-Q Versus IV Furosemide in Acute Heart Failure; NCT02579057).

Use of thermodilution cardiac output overestimates diagnoses of exercise-induced pulmonary hypertension.

Two new definitions of exercise-induced pulmonary hypertension (EIPH) have emerged. Both rely on measuring cardiac output (CO), yet this remains unstandardized. In our cohort of patients undergoing invasive cardiopulmonary exercise testing, we found that using thermodilution CO rather than direct Fick CO led to a significant excess of EIPH diagnoses.

Right Ventricular Functional Reserve in Pulmonary Arterial Hypertension.

BACKGROUND: Right ventricular (RV) functional reserve affects functional capacity and prognosis in patients with pulmonary arterial hypertension (PAH). PAH associated with systemic sclerosis (SSc-PAH) has a substantially worse prognosis than idiopathic PAH (IPAH), even though many measures of resting RV function and pulmonary vascular load are similar. We therefore tested the hypothesis that RV functional reserve is depressed in SSc-PAH patients. METHODS AND RESULTS: RV pressure-volume relations were prospectively measured in IPAH (n=9) and SSc-PAH (n=15) patients at rest and during incremental atrial pacing or supine bicycle ergometry. Systolic and lusitropic function increased at faster heart rates in IPAH patients, but were markedly blunted in SSc-PAH. The recirculation fraction, which indexes intracellular calcium recycling, was also depressed in SSc-PAH (0.32±0.05 versus 0.50±0.05; P=0.039). At matched exercise (25 W), SSc-PAH patients did not augment contractility (end-systolic elastance) whereas IPAH did (P<0.001). RV afterload assessed by effective arterial elastance rose similarly in both groups; thus, ventricular-vascular coupling declined in SSc-PAH. Both end-systolic and end-diastolic RV volumes increased in SSc-PAH patients to offset contractile deficits, whereas chamber dilation was absent in IPAH (+37±10% versus +1±8%, P=0.004, and +19±4% versus -1±6%, P<0.001, respectively). Exercise-associated RV dilation also strongly correlated with resting ventricular-vascular coupling in a larger cohort. CONCLUSIONS: RV contractile reserve is depressed in SSc-PAH versus IPAH subjects, associated with reduced calcium recycling. During exercise, this results in ventricular-pulmonary vascular uncoupling and acute RV dilation. RV dilation during exercise can predict adverse ventricular-vascular coupling in PAH patients.