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Published on: March 7, 2022
Rationale and design of the Myocardial Microinjury and Cardiac Remodeling Extension Study in the Sodium Lowering in
Joanna Leigh Dunlop, Alain Charles Vandal, Janak Rashme de Zoysa
1Faculty of Medical and Health Sciences, University of Auckland, Private Bag 93311, Otahuhu, Auckland 1640, New Zealand. mrmarsh@woosh.co.nz.
Insights
This study investigates if lower sodium in hemodialysis fluid causes heart muscle injury. Results will inform safer dialysis practices for cardiovascular health.
Area of Science:
- Nephrology
- Cardiology
- Clinical Trials
Background:
- The Sodium Lowering in Dialysate (SoLID) trial examines if reduced dialysate sodium lowers left ventricular mass in hemodialysis (HD) patients.
- Observational data suggests lower dialysate sodium may increase mortality risk due to hypotension and myocardial injury.
- The Mac-SoLID study investigates myocardial micro-injury and cardiac remodeling in the context of lower dialysate sodium.
Purpose of the Study:
- To determine if lower dialysate sodium increases high-sensitivity Troponin T (hsTnT) levels, a marker of myocardial micro-injury.
- To assess if lower dialysate sodium leads to increased LV segmental wall motion abnormalities, indicating recurrent myocardial stunning.
- To evaluate detrimental changes in LV geometry resulting from maladaptive homeostatic mechanisms.
Main Methods:
- The Mac-SoLID study is an extension of the SoLID trial, funded by the Health Research Council of New Zealand.
- Patients received either 135 mM or 140 mM dialysate sodium for 12 months.
- Primary outcome: repeated [hsTnT] measures. Secondary outcomes: cardiac MRI for LV segmental wall motion abnormalities, LV mass to volume ratio, and LV remodeling patterns.
Main Results:
- Primary outcome measure is repeated measures of [hsTnT] at 0, 3, 6, 9, and 12 months.
- Secondary outcomes assessed via cardiac MRI at 0 and 12 months.
- Analysis will focus on hsTnT levels, LV segmental wall motion abnormalities, and LV geometry changes.
Conclusions:
- The Mac-SoLID study complements the SoLID trial by investigating cardiovascular health impacts of lower dialysate sodium.
- It assesses if potential benefits of reduced LV mass are offset by myocardial stunning and micro-injury.
- The study aims to provide a comprehensive understanding of the cardiovascular effects of dialysate sodium levels in hemodialysis.
Background:
The Sodium Lowering in Dialysate (SoLID) trial is an ongoing a multi-center, prospective, randomised, single-blind (assessor), controlled, parallel assignment clinical trial, enrolling 96 home and self-care hemodialysis (HD) patients from 7 centers in New Zealand. The trial will evaluate the hypothesis that lower dialysate [Na+] during HD results in lower left ventricular (LV) mass. Since it's inception, observational evidence has suggested increased mortality risk with lower dialysate [Na+], possibly due to exacerbation of intra-dialytic hypotension and subsequent myocardial micro-injury. The Myocardial Micro-injury and Cardiac Remodeling Extension Study in the Sodium Lowering In Dialysate Trial (Mac-SoLID study) aims to determine whether lower dialysate [Na+] results in (i) increased levels of high-sensitivity Troponin T (hsTnT), a well-established marker of intra-dialytic myocardial micro-injury in HD populations, and (ii) increased fixed LV segmental wall motion abnormalities, a marker of recurrent myocardial stunning and micro-injury, and (iii) detrimental changes in LV geometry due to maladaptive homeostatic mechanisms.
Methods/Design:
The SoLID trial and the Mac-SoLID study are funded by the Health Research Council of New Zealand. Key exclusion criteria: patients who dialyse > 3.5 times per week, pre-dialysis serum sodium <135 mM, and maintenance haemodiafiltration. In addition, some medical conditions, treatments or participation in other dialysis trials that contraindicate the study intervention or confound its effects, will be exclusion criteria. The intervention and control groups will receive dialysate sodium 135 mM and 140 mM respectively, for 12 months. The primary outcome measure for the Mac-SOLID study is repeated measures of [hsTnT] at 0, 3, 6, 9, and 12 months. The secondary outcomes will be assessed using cardiac magnetic resonance imaging (MRI), and comprise LV segmental wall motion abnormality scores, LV mass to volume ratio and patterns of LV remodeling at 0 and 12 months.
Discussion:
The Mac-SoLID study enhances and complements the SoLID trial. It tests whether potential gains in cardiovascular health (reduced LV mass) which low dialysate [Na+] is expected to deliver, are counteracted by deterioration in cardiovascular health through alternative mechanisms, namely repeated LV stunning and micro-injury.
Trial Registration:
Australian and New Zealand Clinical Trials Registry number: ACTRN12611000975998.
