Hydration Guided by Bioimpedance

Study Questions:

What is the utility of using bioimpedance vector analysis (BIVA)-guided hydration on the incidence of contrast-induced acute kidney injury (CI-AKI) after elective coronary angiographic procedures?


The HYDRA study authors designed a randomized controlled trial to evaluate the utility of BIVA-guided hydration. A total of 303 patients with low BIVA level on admission were randomized to receive either normal saline at the rate of 1 ml/kg/h (standard hydration) for 12 hours before, and after the procedure, or normal saline at a rate of 2 ml/kg/h. The saline infusion was halved in all patients with a left ventricular ejection fraction (LVEF) <40%. CI-AKI was defined as an increase in levels of cystatin C >10% above baseline at 24 hours after contrast administration.


Randomization to a saline infusion of 2 ml/kg/h was associated with a reduction in the incidence of CI-AKI (11.5% vs. 22.3%; p = 0.015) compared with those receiving standard hydration. An optimal BIVA level was achieved prior to angiography in 50% of patients randomized to 2 ml/kg/h compared with 27.7% in the standard group (p = 0.0001). The findings were consistent in all the prespecified subgroups except for patients with an LVEF <40% in whom no benefit of aggressive hydration was observed (p for interaction = 0.01).


BIVA-guided aggressive hydration is associated with a reduction in the incidence of CI-AKI.


This study adds to the growing data demonstrating the utility of personalized hydration to prevent CI-AKI. The landmark POSEIDON trial (Lancet 2014;383:1814-23) was the first to demonstrate the safety and benefit of LV end-diastolic pressure (LVEDP)-guided hydration in reducing CI-AKI. The added advantage of the POSEIDON protocol is that the duration of hydration is much shorter than was tested in the HYDRA trial. Given the shorter duration, and the lower cost of the POSEIDON protocol, it is unlikely that BIVA-based hydration will supplant LVEDP-guided hydration in routine clinical practice.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: Acute Kidney Injury, Blood Pressure, Coronary Angiography, Cystatin C, Primary Prevention, Sodium Chloride, Stroke Volume, Vascular Diseases

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