Cardiopulmonary exercise testing before and after intravenous iron in preoperative patients: a prospective clinical study

James O M Plumb; James M Otto; Shriya B Kumar; Sitara Bali; Mai Wakatsuki; Walter F J Schmidt; Hugh E Montgomery; Michael P W Grocott; Denny Z Levett

doi:10.1186/s13741-023-00319-x

Cardiopulmonary exercise testing before and after intravenous iron in preoperative patients: a prospective clinical study

Perioper Med (Lond). 2023 Jul 3;12(1):31. doi: 10.1186/s13741-023-00319-x.

Authors

James O M Plumb^{1

2

3

4}, James M Otto^{5

6

7

8}, Shriya B Kumar⁵, Sitara Bali⁵, Mai Wakatsuki⁸, Walter F J Schmidt⁹, Hugh E Montgomery^{10

11}, Michael P W Grocott^#^{5

6

7

8

12}, Denny Z Levett^#^{5

6

7

8}

Affiliations

¹ Perioperative and Critical Care Theme, NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust/University of Southampton, Southampton, UK. j.plumb@soton.ac.uk.
² Centre for Human Integrative Physiology, Faculty of Medicine, University of Southampton, Southampton, UK. j.plumb@soton.ac.uk.
³ Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHSFT, Southampton, UK. j.plumb@soton.ac.uk.
⁴ Shackleton Department of Anaesthesia, University Hospital Southampton NHSFT, Southampton, UK. j.plumb@soton.ac.uk.
⁵ Perioperative and Critical Care Theme, NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust/University of Southampton, Southampton, UK.
⁶ Centre for Human Integrative Physiology, Faculty of Medicine, University of Southampton, Southampton, UK.
⁷ Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHSFT, Southampton, UK.
⁸ Shackleton Department of Anaesthesia, University Hospital Southampton NHSFT, Southampton, UK.
⁹ Department of, Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany.
¹⁰ Centre for Human Health and Performance/Institute of Sport, Exercise and Health, University College London, London, UK.
¹¹ NIHR University College London Hospitals Biomedical Research Centre, London, UK.
¹² Department of Anesthesiology, Duke University School of Medicine, Durham, NC, USA.

^# Contributed equally.

Abstract

Background: Anemia is associated with impaired physical performance and adverse perioperative outcomes. Iron-deficiency anemia is increasingly treated with intravenous iron before elective surgery. We explored the relationship between exercise capacity, anemia, and total hemoglobin mass (tHb-mass) and the response to intravenous iron in anemic patients prior to surgery.

Methods: A prospective clinical study was undertaken in patients having routine cardiopulmonary exercise testing (CPET) with a hemoglobin concentration ([Hb]) < 130 g^.l^-1 and iron deficiency/depletion. Patients underwent CPET and tHb-mass measurements before and a minimum of 14 days after receiving intravenous (i.v.) Ferric derisomaltose (Monofer®) at the baseline visit. Comparative analysis of hematological and CPET variables was performed pre and post-iron treatment.

Results: Twenty-six subjects were recruited, of whom 6 withdrew prior to study completion. The remaining 20 (9 [45%] male; mean ± SD age 68 ± 10 years) were assessed 25 ± 7 days between baseline and the final visit. Following i.v. iron, increases were seen in [Hb] (mean ± SD) from 109 ± 14 to 116 ± 12 g l^-1 (mean rise 6.4% or 7.3 g l^-1, p = < 0.0001, 95% CI 4.5-10.1); tHb-mass from 497 ± 134 to 546 ± 139 g (mean rise 9.3% or 49 g, p = < 0.0001, 95% CI 29.4-69.2). Oxygen consumption at anerobic threshold ([Formula: see text] O_{2 AT}) did not change (9.1 ± 1.7 to 9.8 ± 2.5 ml kg^-1 min^-1, p = 0.09, 95% CI - 0.13 - 1.3). Peak oxygen consumption ([Formula: see text] O_{2 peak}) increased from 15.2 ± 4.1 to 16 ± 4.4 ml^.kg^.-1 min^-1, p = 0.02, 95% CI 0.2-1.8) and peak work rate increased from 93 [67-112] watts to 96 [68-122] watts (p = 0.02, 95% CI 1.3-10.8).

Conclusion: Preoperative administration of intravenous iron to iron-deficient/deplete anemic patients is associated with increases in [Hb], tHb-mass, peak oxygen consumption, and peak work rate. Further appropriately powered prospective studies are required to ascertain whether improvements in tHb-mass and performance in turn lead to reductions in perioperative morbidity.

Trial registration: ClinicalTrials.gov identifier: NCT 033 46213.

Trial registration: ClinicalTrials.gov NCT00000033.

Keywords: Anemia; CPET; Cardiopulmonary exercise testing; Intravenous iron; Surgery; Total hemoglobin mass; tHb-mass.

Associated data

ClinicalTrials.gov/NCT00000033