Preoperative Chest CT-imaging in Surgical Aortic Valve Replacement with or Without CABG

When determining the strategy for aortic valve replacement, echocardiography is still considered the golden standard (1). While pre-procedural MSCT is standard of care in TAVR patients, this is not yet part of routine clinical practice in SAVR patients. The investigators hypothesise that when atherosclerosis of the ascending aorta is identified preoperatively on contrast-enhanced multi-slice computed tomography (MSCT), the subclinical perioperative stroke rate (as detected on diffusion-weighted magnetic resonance imaging (DW-MRI)) can be reduced by modification of the operative strategy if necessary.

The primary objective is to assess whether the use of pre-operative MSCT will reduce subclinical stroke rates (i.e., ischemic brain lesions) as identified with the use of DW-MRI after SAVR with or without concomitant CABG surgery.

The secondary objective is to assess whether the use of pre-operative MSCT will improve neurological assessment score, reduce clinical stroke, mortality, change in intervention strategy (pre- or intra-operatively), cannulation strategy and clamping strategy as well as reduce procedural times and improve quality of life (with the application of EQ-5D and KCCQ questionnaires).

This is a prospective, multicenter, parallel, open-label randomized controlled trial (RCT) with a 1:1 randomization including patients aged 18 years and older accepted for SAVR with or without concomitant CABG by the Heart Team at the St. Antonius Hospital Nieuwegein. All patients enrolled in the study will be randomized to additional pre-operative MSCT or no additional pre-operative MSCT. Postoperatively, a DW-MRI will be made in all patients. The trial will end after 30-day follow-up of all enrolled patients.

The main primary endpoint is the incidence of subclinical stroke rate (i.e., presence of new ischemic brain lesions) as identified with the use of DW-MRI made within one week postoperatively or before discharge. Secondary endpoints include the National Institutes of Health Stroke Scale (NIHSS) score within one week postoperatively (targeted at day two postoperatively), clinical ischemic stroke (conform VARC-3),transient ischemic attack diagnosed by a neurologist within one week postoperatively, defined by transient focal neurological signs or symptoms lasting \< 24 h presumed to be due to focal brain, spinal cord or retinal ischemia, but without evidence of acute infarction by neuroimaging or pathology, or with no imaging performed (conform VARC-3), mortality at discharge (normally at three to five days postoperatively) or within one week postoperatively (if discharge is \> 1 week postoperatively) and at three months postoperatively, the change in intervention strategy, the change in cannulation strategy, the change in clamping strategy, procedural times and the quality of life at three months postoperatively (assessed by EQ-5D and KCCQ)

When severe calcification of the ascending aorta is identified preoperatively on multi-slice computed tomography (MSCT), the operative strategy can be modified if necessary. This could possibly prevent stroke or even mortality in the study patients randomized to additional pre-operative MSCT. The MSCT will take 5-10 minutes. Only low-dose contrast-enhanced CT will be used, which results in a very low radiation risk. With application of too high dosages of contrast, there is a slight chance of kidney insufficiency. Furthermore, an allergic reaction to contrast could occur. However, patients with known allergies to contrast and patients with low renal function will be excluded from participation in this trial.

The patients receiving a preoperative CT-scan will have to be informed about all incidental findings found on the CT-scan. A possible disadvantage is found in the additional costs of a CT-scan, but the costs associated with stroke would outweigh the costs of a preoperative CT-scan. All patients will receive a DW-MRI before discharge. Contra-indications for MRI include pacemaker wires or implantable cardioverter defibrillators (ICDs), metallic implants, cochlear/ear implants, Swan-Ganz catheter, claustrophobia and contrast allergy. The presence of an aortic valve prosthesis is not a contra-indication for DW-MRI scanning.

All patients will be asked to fill out a questionnaire at baseline and within 90 days postoperatively. Since this will soon be implemented as part of standard care, the latter is not seen as extra burden for the patients.

• National Institutes of Health Stroke Scale [Time frame: within one week postoperatively (targeted at day two postoperatively)]
• Clinical ischemic stroke (conform VARC-3) [Time frame: Within one week postoperatively]
• TIA diagnosed by a neurologist [Time frame: One week postoperatively]
• Change in intervention strategy [Time frame: After hospital admission but before the end of surgery]
• Change in cannulation strategy [Time frame: During procedure]
• Change in clamping strategy [Time frame: During procedure]
• Procedural times [Time frame: During procedure]
• Quality of life at three months postoperatively (assessed by EQ-5D and KCCQ) [Time frame: At baseline (prior to procedure) and 90 days post procedure]