Clinical Trial Details
— Status: Recruiting
Administrative data
NCT number |
NCT02632760 |
Other study ID # |
605/15 |
Secondary ID |
|
Status |
Recruiting |
Phase |
Phase 4
|
First received |
|
Last updated |
|
Start date |
July 15, 2016 |
Est. completion date |
June 2024 |
Study information
Verified date |
January 2023 |
Source |
Bayside Health |
Contact |
Paul S Myles, MD |
Phone |
+61390762000 |
Email |
p.myles[@]alfred.org.au |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
This randomised double-blind, controlled phase IV trial will compare the efficacy, safety and
cost-effectiveness of preoperative IV iron with placebo in patients with anaemia before
elective cardiac surgery.
Description:
Preoperative anaemia is common (≈30%) in patients awaiting cardiac surgery, and is associated
with increased complications, ICU and hospital stay, and mortality. The extent of anaemia is
worsened by haemodilution occurring with cardiopulmonary bypass and surgical bleeding
(average blood loss 0.5-1.5 litres), which in turn impair end-organ blood flow and tissue
oxygen delivery. Further, the need for blood transfusion is greatly increased in anaemic
patients, and is associated with poor outcomes. In addition, blood transfusions are costly
(>$700 per unit), with around 50% of all transfusions used in surgery being for cardiac
surgery. The investigators have identified high rates of bleeding complications and
transfusion requirements in Australian cardiac surgery; and in another international
collaboration, it was found that anaemia, transfusion and kidney injury are inter-related
after cardiac surgery. After risk-adjustment, the combination of these three risk factors was
associated with a 3.5-fold (95% CI 2.3-5.2) increased odds of kidney injury.
Both anaemia and red cell transfusion are independent risk factors in major surgery. Some of
the investigators reviewed Australian cardiac surgery patients from six Victorian hospitals,
2005-2011. We linked the ANZ Society of Cardiothoracic Surgeons cardiac surgery database to
laboratory data, including preoperative haemoglobin and all issued blood products (manuscript
in preparation). Anaemia was defined according to the WHO definition (Hb <130 g/L for males
and <120 g/L for females). There were 15,948 cardiac surgery patients available for inclusion
in the analysis, of which 28% were anaemic. Anaemic patients were more likely to receive a
red cell transfusion (71% vs. 40%, p<0.001), more transfused units of blood (median 4 [IQR
2-8] vs. 3 [2-5], p<0.001), and had higher 30-day mortality (5.4% vs. 1.9%, p<0.001), new
renal failure (43% vs. 26%, p<0.001), and longer hospital stay in survivors (13 days [8-23]
vs. 8 days [6-14], p<0.001). After multivariable adjustment, preoperative anaemia was an
independent predictor of mortality (adj. OR 1.46, 95% CI 1.14-1.88, p=0.003). Similar results
were obtained when restricted to elective surgery, but with hospital stay 9 days (7-17) vs. 7
days (6-11), p<0.001. Other large studies are consistent with this.
The investigators have also analysed data for patients undergoing major non-cardiac surgery
from the American College of Surgeons' National Surgical Quality Improvement Program database
(a validated outcomes registry from 211 hospitals worldwide). In 227,425 patients undergoing
noncardiac surgery, and found that preoperative anaemia was associated with increased 30-day
mortality (adj. OR 1.42, 95% CI 1.31-1.54) and morbidity (adj. OR 1.35, 1.30-1.40).
Alfred hospital (Melbourne) transfusion data for 2012-14 (n=2,091) show that anaemic (27% of
cohort) and non-anaemic cardiac surgical patients had intraoperative red cell transfusion
rates of 31% and 14%, respectively; p<0.01.
Iron deficiency is the commonest cause of anaemia worldwide, and iron deficiency per se
independently worsens outcomes after surgery. The traditional textbook definition of iron
deficiency anaemia refers to depletion of the body's iron stores due to dietary deficiency or
chronic blood loss - an absolute iron deficiency. Chronic disease and inflammation have a
direct effect in the pathway of iron absorption and metabolism leading to a state of
functional iron deficiency and anaemia. Specifically, the iron regulatory protein hepcidin is
upregulated, blocking pathways of iron transport. This prevents iron absorption from the gut,
further uptake by the reticuloendothelial system increases stores (ferritin), but
distribution and transfer to the bone marrow is blocked. Consequently, despite normal or even
increased body iron stores (with normal ferritin levels), these are artifactual, and a state
of 'functional iron deficiency' exists. This is commonly seen in renal and cardiac disease
and increasingly recognised as a cause for anaemia in the surgical patient. Importantly, IV
iron has been shown to overcome this functional deficiency and correct anaemia.
IV iron therapy is effective in treating anaemia in medical (heart failure, kidney disease),
post-partum, and preoperative settings (orthopaedic surgery, colon cancer resection,
hysterectomy, hip/knee joint replacement. Earlier IV iron preparations using high molecular
weight dextran were associated with anaphylaxis due to pre-formed antibodies, but newer
preparations are safer, enabling delivery of a full treatment dose in 15 mins, so iron can be
administered safely and quickly in outpatients. It is now readily available in Australia and
is PBS-listed. This gives patients the equivalent dose of 12 months of tablets in only 15
mins.
Iron deficiency is very common in patients having coronary artery surgery. It is highly
plausible that anaemia correction will improve patient outcome following cardiac
surgery.However, some data suggest that free iron mediates free radical production associated
with organ damage or infection in surgery and this balance between effective anaemia
correction and potential risk needs further research. A definitive large trial is needed to
determine if IV iron safely, effectively, and promptly corrects preoperative anaemia, and
thus reduces risk in cardiac surgery.
The investigators undertook a Cochrane review of iron therapy to treat anaemia in adults
including 4,745 participants in 21 trials. This found a trend for better haemoglobin levels
with IV iron (MD 0.50 g/dL, 95% CI 0.73-0.27; six studies, N=769) but with considerable,
unexplained heterogeneity. Differences in the proportion of participants requiring
transfusion were imprecise (RR 0.84, 95% CI 0.66-1.06; 8 studies, N=1,315). Thus the current
evidence base is sparse; few randomised trials have been done and these were too small -
there remains considerable equipoise.
Review of the literature on anaemia and iron therapy in cardiac surgery, which included 4
small trials of IV iron. Overall, half of all cardiac surgery patients were anaemic before
surgery. Preoperative anaemia was found to be independently associated with higher mortality
and blood transfusion rate, as well as longer ICU and hospital stay. As also shown by others,
preoperative haematocrit was a powerful independent predictor of mortality, renal failure and
deep sternal wound infection. In adjusted analyses each 5 point decrease in preoperative
haematocrit was associated with an 8% increased risk of death (OR, 1.08; p<0.0003), a 22%
increased risk of postoperative renal failure (OR, 1.22; p<0.0001), and a 10% increased risk
of deep sternal wound infection (OR, 1.10; p<0.01). There is a need for a well-designed,
pragmatic trial to assess the role of preoperative anaemia treatment using IV iron in
patients undergoing cardiac surgery.