[The dobutamine-dopamine combination versus amrinone in congestive heart failure with a marked edematogenic sign complicated by functional kidney failure. A comparison between 2 different models of inotropic stimulation and diuresis potentiation].

BACKGROUND: We evaluated the diuretic output in patients with decompensated chronic heart failure (CHF), previously treated by i.v. infusion with dobutamine and dopamine (dob-dop) or with amrinone (amr). Our target was to identify the possible discrepancies in urinary output perhaps linked to the different type of inotropic stimulation in the two subsets.

METHODS: Adjunctive therapy with dob-dop or amr was chosen because the administration of diuretics only, without cardiac support, as tested in previous hospitalizations, had been demonstrated to produce unfavourable results, mainly expressed by finding of a low output syndrome in 50% of cases or more. The administration of i.v. infusion was maintained during 17 hours (1000 min approximatively), and included infusion in separate pumps of the two amines, dobutamine at dose of 5 micrograms/kg/min and dopamine at dose of 2.8 micrograms/kg/min or, alternatively, i.v. infusion of amr, administered at dose of 7 micrograms/kg/min. Infusion volumes were similar in the two subsets. The two subsets were homogeneous relatively to renal impairment, i.e. to the parameters (urinary Na, U/P creatinine, U/P urea, urinary osmolality) we fixed as markers idoneous to demonstrate the occurrence of organic renal damage (acute tubular necrosis).

RESULTS: The diuresis was recovered in all 24 patients, and the urine volume resulted more pronounced in the subset attributed to the dob-dop at both the 8th and the 17th hour readings. We found no harmful alterations in HR and AP, whereas renal function parameters have been shown to enhance in both the dob-dop and amr arms. The diuretic effectiveness of the SIEV obtained by catecholamine implementation exercised a synergistic, favourable effect on diuresis, renal flow, glomerular filtration rate, and sodium post-proximal delivery. Amr resulted less effective then dob-dop simultaneous administration relatively to the diuretic effect. No remarkable differences were found in the two subsets as regards the heart rate, whereas a decrease in arterial pressure was found after amr. A persistent shift towards a condition of chronic renal failure, was identified in 4/24 patients, the two groups despite of the prolonged treatment at optimized doses: no remarkable side effects were reported.

CONCLUSIONS: Thus, the selective effect upon renal hemodynamics, as exercised by dob-dop infusion low doses of dop, together with the enhanced renal output due to dob, has been shown to be more effective than amr influence: thus, the catecholamine therapeutical approach has been demonstrated to possess the best effectiveness in excitation of diuresis, among the CHF oliguric patients.