Left ventricular untwist determines intradialytic hemodynamics and outcomes in mildly reduced and preserved ejection fraction patients.

Hypotension during hemodialysis (HD) is common in patients with reduced ejection fraction (EF), but its occurrence in those with mildly reduced or preserved EF is less clear. We hypothesized that intravascular hypovolemia during HD impairs hemodynamics when left ventricular (LV) untwisting is compromised. We studied 70 patients on maintenance HD ≥2 years (mean age 50 ± 15; 41% female), all with LVEF ≥40%. Echocardiography assessed global longitudinal strain (GLS) and LV torsion, analyzed with functional data methods. Lower systolic blood pressure (SBP) was independently associated with older age (p = 0.001) and higher ultrafiltration (p = 0.009), while larger inferior vena cava diameter correlated with higher SBP (p = 0.007). Greater diastolic untwist was significantly associated with higher SBP (global p = 0.034), whereas GLS showed no significant association (global p = 0.098). During a median 9.2-month follow-up, six patients (8%) died. LV torsion was associated with lower mortality (global p = 0.10), with significant effects across the diastolic untwist phase. In contrast, more negative GLS during diastole was associated with increased mortality (global p = 0.03). These findings suggest that better diastolic untwisting may improve hemodynamic stability and outcomes in HD patients with preserved or mildly reduced LVEF.