Comparative analysis of the therapeutic effects of long-acting and short-acting loop diuretics in the treatment of chronic heart failure using 123I-metaiodobenzylguanidine scintigraphy

Aims Loop diuretics are essential for the treatment of chronic heart failure (CHF) but short-acting diuretics are reported to induce sympathetic nervous system (SNS) activation. This study was performed to compare therapeutic effects of two loop diuretics, long-acting azosemide and short-acting furosemide, using I-123-metaiodobenzylguanidine (I-123-MIBG) scintigraphy. Methods and results Twenty-two patients with New York Heart Association class II-III heart failure and left ventricular dysfunction, who required treatment with a loop diuretic, were included. In this crossover study, 11 patients were randomized to azosemide treatment first and the remaining 11 patients to furosemide. Treatments were administered for 6 months and then patients were crossed over to the second treatment. I-123-MIBG scintigraphy was performed before and 6 months after the start of treatment with each loop diuretic. Early and delayed images were obtained 20 min and 4 h after administration of I-123-MIBG, respectively; and the heart/mediastinum (H/M) ratio and washout rate (WR) were measured. In addition, left ventricular ejection fraction (LVEF), levels of brain natriuretic peptide (BNP), and norepinephrine were measured before and 6 months after the start of treatment. No differences were observed between the two groups in terms of concomitant medication, cause of heart failure, H/M ratio, WR, BNP, norepinephrine, or LVEF. The azosemide group exhibited a significant increase in delayed image H/M ratio, and a significant decrease in WR and norepinephrine after the final administration compared with the furosemide group. Conclusion This study indicates that azosemide suppresses SNS activation compared with furosemide in patients with CHF, suggesting that long-acting loop diuretics may have more beneficial effects on the prognosis of CHF.