Myocardial contractility does not determine the haemodynamic response during dialysis.
BACKGROUND
LV systolic dysfunction in dialysis patients has been implicated in the genesis of dialysis hypotension. End-systolic elastance (E(es)), a relatively load-independent parameter of myocardial contractility, was assessed by testing the acute left ventricular (LV) response to nitroglycerine (NTG) in hypotension-prone (HP) and hypotension-resistant (HR) patients.


METHODS
Routine measurement of ejection fraction (EF) was done before dialysis in 15 patients without significant valvular disease or symptoms of coronary heart disease. Continuous arterial pressure was measured by Finapres, with systolic blood pressure (SBP) as surrogate for LV end-systolic pressure. Simultaneously, LV area was measured using automated border detection. SBP and LV area data were combined online to create pressure-area loops in real time following intravenous NTG bolus. E(es) was determined offline by beat-to-beat analysis of consecutive pressure-area loops.


RESULTS
SBP, at baseline 168 mmHg (128-188 mmHg), decreased to 127 mmHg (79-161 mmHg). End-systolic LV area, at baseline 6 cm2 (1-12 cm2), decreased to 4 cm2 (1-10 cm2). E(es) in the HP group (11 mmHg cm(-2); 7-22 mmHg cm(-2)) was not different from E(es) in the HR group (9 mmHg cm(-2); 4-16 mmHg cm(-2)). EF was 61% (45-73%). There was no correlation between E(es) and EF.


CONCLUSIONS
In this population of dialysis patients without clinically manifest heart disease, the HP and HR groups had a similar E(es). Therefore, these two types of dialysis patients were not distinguished by a difference in myocardial contractility. The results of this study argue against a role for reduced myocardial contractility in the genesis of intradialytic hypotension.
Ie
Eric H Y
EH
Department of Medicine, Erasmus MC, Dr Molewaterplein 40, 3015 GD Rotterdam, the Netherlands. e.ie@erasmusmc.nl
Krams
Rob
R
Vletter
Wim B
WB
Nette
Robert W
RW
Weimar
Willem
W
Zietse
Robert
R
D000328:Adult; D000368:Aged; D018450:Disease Progression; D004452:Echocardiography; D006801:Humans; D007022:Hypotension / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000503:physiopathology / Q000628:therapy*; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D006435:Renal Dialysis / Q000009:adverse effects*; D013318:Stroke Volume / Q000502:physiology; D017725:Ventricular Pressure / Q000502:physiology