Mid-Term Impact of Kampo Goreisan in Patients with Congestive Heart Failure Receiving Tolvaptan-Incorporated Medical Therapy

Background: Despite considerable advances in contemporary pharmacotherapy for heart failure (HF), residual congestion continues to drive adverse outcomes in a substantial proportion of patients. Goreisan, a traditional Kampo herbal formulation, has seen growing clinical application as an adjunct for refractory fluid retention; yet the prognostic implications of sustaining versus withdrawing goreisan among patients on tolvaptan-based regimens have not been adequately characterized. Methods: We conducted a retrospective single-center observational analysis enrolling patients with HF who received goreisan alongside tolvaptan-incorporated medical therapy between April 2022 and November 2025. Enrolled patients were classified into a continuation group or a termination group based on their subsequent goreisan treatment course. The primary endpoint was defined as a composite of all-cause death and HF-related hospitalization requiring intravenous diuretic therapy. Results: Among 25 patients, 12 maintained goreisan throughout the observation period while 13 underwent treatment termination. Baseline clinical profiles were broadly similar across the two groups. The continuation group exhibited a significantly reduced cumulative incidence of the primary endpoint relative to the termination group (p = 0.036). Negative binomial regression revealed a markedly elevated event rate in the termination group (incidence rate ratio 9.27; 95% confidence interval 2.05–42.0; p = 0.004), with adverse events demonstrating a pronounced temporal clustering in the immediate post-discontinuation period. Conclusions: Among patients with HF and refractory congestion on tolvaptan-incorporated therapy, maintaining goreisan was associated with a trend toward fewer clinical events and longer periods of hemodynamic stability, whereas its withdrawal appeared to be followed by early adverse outcomes. Given the small sample size and observational design, no definitive conclusions can be drawn, and these findings should be regarded strictly as preliminary and hypothesis generating; prospective controlled studies with larger cohorts are needed before any clinical implications can be established.