155 - The Effect of Major Vascular Surgery on Oxidized LDL, its Antibodies, Complement and Complexes (ID 246)
- Adam Hartley, United Kingdom
- Magapu Pradeep, United Kingdom
- Hasan A. Shah, United Kingdom
- Mohammed Allaf, United Kingdom
- Anna Chow, United Kingdom
- Ameer H. Khan, United Kingdom
- Mikhail Caga-Anan, United Kingdom
- Michael Fisher, United Kingdom
- Dorian Haskard, United Kingdom
- Ramzi Khamis, United Kingdom
Abstract
Background and Aims
We aimed to investigate if major surgery induces LDL oxidation and whether the
innate immune system components, including antibodies against oxidized LDL (oxLDL) (such
as malondialdehyde-modified LDL (MDA-LDL)) and complement (eg. C3), are changed
dynamically in this context. We also assess for relationships between these biomarkers and
post-operative cardiovascular events.
Methods
Plasma samples were obtained from a prospective cohort of 131 patients
undergoing major non-cardiac vascular surgery at Liverpool Heart and Chest Hospital, with
samples obtained at baseline, 24-hours and 72-hours postoperatively. ELISAs were
developed to assess MDA-LDL, anti-MDA-LDL antibodies, C3 and their respective immune
complexes. The primary endpoint was acute coronary syndrome (ACS). Secondary endpoints
were defined as unstable angina, stroke, pulmonary embolism or all-cause mortality. All
endpoints were measured until hospital discharge.
Results
MDA-LDL adjusted to Apolipoprotein B-100 (ApoB) and C3 significantly increased at
24-hours, whereas IgG and IgM anti-MDA-LDL antibodies reduced post-operatively
(p<0.0001, p<0.0001, p=0.0017 and p=0.0243 respectively). IgG-oxLDL and IgM-oxLDL
complexes corrected to ApoB significantly reduced (both p<0.0001), whereas C3-oxLDL
complex significantly increased at 24-hours (p=0.0097). Baseline IgG anti-MDA-LDL levels
were higher in primary endpoint patients (p=0.0402). There was also a significant increase in
MDA-LDL/ApoB at 24-hours in patients with composite endpoints (p=0.0238).
Conclusions
Major non-cardiac vascular surgery resulted in either the production or release
of MDA-LDL, with a corresponding decrease in antibody levels and their corresponding
oxLDL complexes, possibly indicating a protective homeostatic function. These novel assays
may have the potential for clinical use as biomarkers of lipoprotein immune handling and
for prediction of post-operative cardiovascular events.
