Proefschrift Jansen Klomp

General introduction and outline
GENERAL INTRODUCTION
Cardiothoracic surgery is considered a major surgical procedure with a postoperative
period that is characterized by a considerable impairment of the quality of life 1
and cognitive function. 2,3 From a patients’ perspective, this short-term burden of
cardiothoracic surgery is acceptable only in the prospect of an improvement in the
long-term prognosis and quality of life. Post-operative neurological complications
directly interfere with these aims of cardiac surgery. Improving the safety of surgery
and reducing post-operative complications should thus be a constant objective.
Post-operative stroke is a multifactorial process, but the mobilization of emboli
during manipulation of aortic atherosclerosis is believed to play a central role. 4–10
Release of emboli has also been associated with post-operative delirium, cognitive
dysfunction, 11 renal dysfunction, 12 and mortality. 13,14 The central hypothesis
underlying this thesis is that accurate detection of aortic atherosclerosis can lead
to effective changes in the surgical management and a subsequent reduction in
post-operative complications.
The distal ascending aorta (DAA) is an area of particular interest, since this is the part of
the aorta most often manipulated during surgery, e.g. during aortic cannulation or the
placement of a cross-clamp. 15 Although accurate visualization of this part of the aorta
is possible with epiaortic ultrasound, 16 this imaging modality is infrequently used. 17
Transesophageal echocardiography (TEE) is applied more routinely for perioperative
monitoring. Although TEE can accurately visualize atherosclerosis of the proximal
ascending- and descending aorta, 34,35 the sensitivity for atherosclerosis of the DAA,
aortic arch and branching vessels is severely impaired by the air-filled trachea. 36
A pragmatic and effective solution for this limitation of conventional TEE is the
positioning of a balloon in the trachea and left main bronchus, which after inflation
with saline provides a view to the upper thoracic aorta. 18–20 This method (“modified
TEE” or “A-View”) was first described in a feasibility study in 2007. 18 The diagnostic
accuracy of modified TEE for the diagnosis of atherosclerosis of the DAA was studied
in 465 patients and compared to epiaortic ultrasound. 20 This study showed that
modified TEE is an accurate test (area under curve: 0.89) with a high sensitivity but
lower specificity (95% and 79% respectively). Modified TEE is thus more suited for
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