Right Ventricular Stroke Work Index

Recently, long-term outcomes of pre-capillary pulmonary hypertension (PH) have been improved, whereas morbidity and mortality are still high because of right-sided heart failure (HF). Right-sided HF is closely related to right ventricular (RV) function and hemodynamics such as RV stroke work index (RVSWI). However, the association between RVSWI and long-term outcomes in pre-capillary PH has not been well investigated. The aims of this study were to compare clinical characteristics between low RVSWI and high RVSWI and to investigate the association between low RVSWI and long-term outcomes in patients with pre-capillary PH. We included patients admitted to diagnose and evaluate PH by right heart catheterization between 2007 and 2015. Patients with pre-capillary PH were divided into two groups according to the median value of RVSWI (low RVSWI group: RVSWI < 19.7 g・m/m²/beat; high RVSWI group: RVSWI ≥ 19.7 g・m/m²/beat). Kaplan-Meier survival curves were applied to investigate whether the low RVSWI were associated with HF death or HF readmission in patients with pre-capillary PH. A total of 36 patients with pre-capillary PH who were diagnosed as pulmonary arterial hypertension (PAH) or chronic thromboembolic PH (CTEPH) were allocated into the low RVSWI group (n = 18) and high RVSWI group (n = 18). The event-free survival rate was significantly lower in the low RVSWI group as compared with the high RVSWI group (P = 0.02). In conclusion, lower RVSWI was significantly associated with HF death or HF readmission in patients with PAH or CTEPH.