Cardio-Ankle Vascular Index Reflects the Efficacy of Waon Therapy in Heart Failure Patients

Waon therapy is a form of thermal treatment in a dry sauna developed by Tei. Although Waon therapy is reportedly effective for chronic heart failure (CHF) patients, not all patients respond to the therapy. The reason for this ineffectiveness has not been fully clarified. The cardio-ankle vascular index (CAVI) is an index of arterial stiffness of the arterial tree from the origin of the aorta to the ankle, and it is thought to reflect some of the afterload of the left ventricle. We investigated the effects of Waon therapy on CAVI and plasma brain natriuretic peptide (BNP) level to clarify the usefulness of CAVI during Waon therapy.CHF patients (n = 21) treated with Waon therapy (2 weeks of 10 sessions) were divided into two groups: responders with an improved BNP level (n = 11) and nonresponders with no improvement in BNP (n = 10). CAVI was measured using Vasela 1500.A significant decrease in CAVI (median and interquartile range) was observed in the responder group (from 10.3 [9.6, 11.6] to 9.6 [8.6, 10.3], P = 0.021), whereas no change was observed in the nonresponder group (from 9.6 [8.6, 10.5] to 9.5 [9.1, 11.2], P = 0.919). The incidence of rehospitalization or cardiac death due to heart failure was significantly higher in patients in whom Waon therapy was ineffective at 12 months of follow-up (log-rank P = 0.001).The effectiveness of Waon therapy in CHF patients may be reflected by the improvement in CAVI.