Patient co-morbidities
Importantly, many patients undergoing TAAA repair will have pre-existing
coronary artery disease (CAD) and associated risk
factors20. Significant (but possibly silent) cardiac
disease may reduce patient tolerance of thoracic aortic cross-clamping,
an obligatory procedure that immediately increases afterload, and left
ventricular stress, upon the heart21. Oxygen
deprivation in proximal tissues and sympathoadrenal discharge constricts
arterioles and is typically accompanied by arteriovenous shunting.
Whilst acute (CPET) exercise may not replicate the profound
physiological challenges imposed by cross-clamping, assessing the
patient’s body under ‘simulated’ (physical) stress and corresponding
systemic response to microcirculatory hypoxaemia may determine how well
systemic tissue perfusion adapts to the surgical insult.
Furthermore, there is mounting evidence that the risk of developing
spinal cord ischaemia is increased by up to 80% in those with
CAD23. Identification of disease may not negate
surgery but may lead to optimisation by coronary artery stenting or
instigating antiplatelet therapy prior to any planned
procedure21, 24. Connective tissue disorders represent
an additional major risk factor for thoracic aortic disease with up to
20% of patients expressing at least one ‘high-risk’
gene25. Marfan syndrome (MS) is one such genetic
disorder and typically presents in younger patients26.
Giske et al. focused on pulmonary function and rehabilitation in
patients with MS and found that V̇ O2PEAK was 30%
and 50% lower in females and males respectively, compared to healthy
(non-MS) controls27.