SUSTAINED IMPROVEMENT IN FUNCTIONAL-CAPACITY AFTER REMOVAL OF BODY-FLUID WITH ISOLATED ULTRAFILTRATION IN CHRONIC CARDIAC-INSUFFICIENCY - FAILURE OF FUROSEMIDE TO PROVIDE THE SAME RESULT

OBJECTIVES: This study was designed to investigate whether a subclinic al accumulation of fluid in the lung interstitium associated with mode rate congestive heart failure interferes with the patient's functional capacity, and whether furosemide treatment can promote reabsorption o f the excessive fluid. BACKGROUND: In patients With moderate congestiv e heart failure, pulmonary overhydration may be detected by chest roen tgenography even if therapy is optimized to keep the urinary output no rmal and to prevent weight gain and dependent edema formation. Removal of the overhydration may help define its significance.METHODS: Patien ts, whose regimens of digoxin, oral furosemide, and angiotensin-conver ting enzyme (ACE) inhibitor therapy were kept constant, were randomly allocated to receive ultrafiltration (8 cases) or an intravenous bolus of supplemental furosemide (mean dose: 248 mg; 8 cases). The amount o f body fluid removed with each method approximated 1600 mL. Functional performance was assessed with cardiopulmonary exercise tests. RESULTS : Soon after fluid withdrawal by either method, the filling pressures of the two ventricles and body weight were reduced and plasma renin ac tivity, norepinephrine, and aldosterone were augmented. After furosemi de administration, hormone levels remained elevated for the next 4 day s, and during this period, patients had positive water metabolism, rec overy of the elevated ventricular filling pressures, and reoccurrence of lung congestion with no improvement in functional capacity. After u ltrafiltration, levels of renin, norepinephrine, and aldosterone fell to below control values within the first 48 hours and water metabolism was equilibrated at a new set point (less fluid intake and diuresis w ithout weight gain). The favorable circulatory and ventilatory adjustm ents consequent to the reabsorption of lung water improved the functio nal capacity of these patients. That may also have restored the lung's ability to clear norepinephrine, thus restraining its facilitation of renin release. The improvement continued 3 months after the procedure . CONCLUSIONS: In patients with congestive heart failure the set point of fluid balance is altered in spite of oral furosemide therapy, supp lemental intravenous furosemide does not shift the set point, at least not when combined with ACE inhibition. Excessive, although asymptomat ic, lung water limits the functional capacity of the patient.