# Decrease in Haemoglobin in Association with Aneurysm Volume Loss after Endovascular Repair of Abdominal Aortic Aneurysm

## TL;DR

This study found that lower haemoglobin levels after abdominal aortic aneurysm repair are linked to aneurysm volume loss and hypertension.

## Contribution

The study identifies a novel association between post-operative haemoglobin decrease and aneurysm volume loss following EVAR.

## Key findings

- Post-operative haemoglobin levels were negatively correlated with aneurysm volume loss (r = –0.252, p = 0.041).
- Hypertension increased the risk of anaemia 24 hours after EVAR by 5.3 times.
- Pre-operative haemoglobin level acted as a protective factor against post-EVAR anaemia.

## Abstract

Anaemia (low haemoglobin [Hb]) is well known to be
associated with high mortality and adverse cardiac events following surgical
treatment of abdominal aortic aneurysm (AAA). However, little is known about the
relationship of AAA volume and Hb level alterations with endovascular repair of
AAA. This study aimed to examine the changes in the Hb level and aneurysm volume
before and after endovascular aneurysm repair (EVAR) for AAA and determine the
relationship between the post-operative Hb level and the volume loss of AAA.

This retrospective study reviewed patients with AAA who
underwent EVAR between January 2020 and February 2021 at a tertiary medical
centre. The clinical features and medical history of the patients were analysed.
Alterations in the Hb level were recorded, and the AAA volume was calculated from
computed tomography angiography images before and after EVAR to infer the
association between the post-operative Hb level and alterations in AAA volume.
Moreover, AAA volume, pre-operative Hb level and medical history were studied to
identify the risk factors for anaemia 24 h after EVAR.

A total
of 74 patients (mean age, 67 ± 7.9 years) were included in this study. The
Hb level decreased significantly 24 h after EVAR, and the post-operative Hb level
was negatively correlated with AAA volume loss (r = –0.252, p =
0.041). No relationship was observed between AAA volume loss and decrease in the
Hb level (r = 0.072, p = 0.571) or between pre-operative AAA
volume and decrease in the Hb level (r = 0.072, p = 0.566).
Furthermore, 59.5% of the patients (n = 44) developed anaemia 24 h after EVAR.
The odds ratio (OR) of anaemia 24 h after EVAR was 5.3 times higher in those with
hypertension (OR, 5.304; 95% confidence interval [CI], 1.024–27.424) than in
those without the condition. The pre-operative Hb level (or normal Hb level) was
a protective factor (OR = 0.909; 95% CI, 0.853–0.969). The area under the
receiver operating characteristic curve was 0.840. The post-operative Hb level
declined significantly, and AAA volume loss contributed to it. Moreover,
hypertension was identified to be a risk factor for anaemia 24 h after EVAR, and
pre-operative Hb level was discerned to be a protective factor.

The findings suggest that decrease in the Hb level in the
early post-EVAR stage warrants the attention of surgeons, especially in patients
with a history of hypertension or a low pre-operative Hb level.