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

## TL;DR

This study shows that better left ventricular untwisting during dialysis helps maintain blood pressure and improves survival in patients with mild or normal heart function.

## Contribution

The study identifies left ventricular untwisting as a key factor in hemodynamic stability during hemodialysis in patients with preserved or mildly reduced ejection fraction.

## Key findings

- Greater diastolic untwist was significantly associated with higher systolic blood pressure during hemodialysis.
- LV torsion during diastolic untwist was linked to lower mortality in hemodialysis patients.
- More negative global longitudinal strain during diastole was associated with increased mortality.

## Abstract

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.

In patients undergoing hemodialysis with mildly reduced or preserved left ventricular ejection fraction, stronger diastolic LV untwisting supports blood pressure maintenance and is associated with improved survival. Impaired untwist, reflecting delayed diastolic recoil, predisposes to intradialytic hypotension and adverse outcomes. These findings identify LV untwist as a key physiological determinant of hemodynamic tolerance to fluid removal during dialysis.