OBJECTIVES Aortic steal is an underestimated risk factor for intraoperative spinal cord ischaemia. A negative effect on spinal cord perfusion in thoraco-abdominal aneurysm repair has been suspected if blood drains away from the cord initiated by a reversal of the arterial pressure gradient. The amount of blood and pressure loss via back-bleeding of segmental arteries and the impact of distal aortic perfusion (DaP) have not been analysed yet. The aim of our study was to quantify ‘segmental steal’ in vivo during simulated thoraco-abdominal aneurysm repair and to determine the impact of DaP on steal and spinal cord perfusion. METHODS Ten juvenile pigs were put on cardiopulmonary bypass with DaP and visceral arteries were ligated. ‘Segmental steal’ was quantified by draining against gravity with/without DaP. Blood volume of ‘segmental steal’ was quantified and microspheres were injected for Post mortem spinal cord perfusion analysis. ‘Segmental steal’ was quantified with/without DaP—and with stopped DaP. RESULTS Quantification revealed a significantly higher steal on cardiopulmonary bypass with DaP with a mean difference of 24(11) ml/min. In all spinal cord segments, blood flow was diminished during steal drainage on DaP, compared to ‘no steal’. The least perfused region was the low thoracic to upper lumbar segment. CONCLUSIONS ‘Segmental steal’ is a relevant threat to spinal cord perfusion—even with the utilization of DaP—diminishing spinal cord perfusion. The blood volume lost by back-bleeding of segmental arteries is not to be underestimated and occlusion of segmental arteries should be considered in thoraco-abdominal aneurysm repair.

Background: Concomitant replacement of the aortic root and aortic valve is a widely used treatment strategy in elective patients with aortic valve stenosis and root aneurysm. It is also a strategy frequently employed in patients with acute aortic dissection type A (AADA), involving the aortic root. Although more patients have undergone valve sparing procedures over the past decades, the classic 'modified Bentall technique' remains a valid option, particularly for patients with a bicuspid aortic valve (BAV). We aimed to compare the results of elective and emergency modified Bentall procedures in patients with bicuspid and tricuspid aortic valves (TAVs).Methods: We retrospectively reviewed our database for patients undergoing either elective or emergency modified Bentall procedures between 2000 and 2018 and identified 827 elective cases (44% BAV) and 258 emergency cases (15% BAV). Analysis of intra-and postoperative outcomes and early mortality was performed. Due to inequality of the groups, a matching analysis was performed.Results: We found BAV patients to be significantly younger (elective: 58±18 vs. 65±14, P<0.001; emergency: 49±17 vs. 62±19, P<0.001) and healthier at time of surgery. In the AADA cohort, malperfusion rate was not different between bicuspid and tricuspid patients, however bicuspid AADA patients presented more often with an entry in the aortic root. After matching, procedure times and early outcomes did not differ between the groups, except for significantly higher rates of respiratory failure in elective TAV patients (10% vs. 5%, P=0.033). The 30-day mortality was 2% in elective cases and 22% in emergency AADA surgery. A subgroup analysis of elective patients with aortic diameter <55 mm also showed excellent outcomes.Conclusions: After adjustment for preoperative inequalities, no differences in early mortality and outcomes were found between bicuspid and tricuspid patients receiving elective or emergency modified Bentall surgery.

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Purpose Efficacy of near-infrared spectroscopy monitoring of paraspinal collateral network (cnNIRS) has been shown to provide additional safety in extensive aortic repair. Better understanding of available cnNIRS monitoring systems regarding differences in performance for this specific purpose is required. Methods Two systems (FORE-SIGHT®, CAS Medical Systems, USA and INVOS™ 5100C; Medtronic, Ireland) used at 4 paravertebral levels (mid and lower thoracic, upper and lower lumbar) were compared in an acute large animal model during three different experimental sequences mimicking relevant clinical scenarios: segmental artery (SA) occlusion by (1) open-access clip-occlusion (n = 7), (2) endovascular coil-embolization (n = 9) and distal circulatory arrest via (3) aortic cross-clamping (n = 9). Results Significant differences in oxygenation measurements between devices were observed only at the lower thoracic level during SA clipping and aortic cross-clamping (p < 0.001). During SA clipping, FORE-SIGHT and INVOS demonstrated reduction to 85% and 72% of baseline values after occlusion of the mid-thoracic region, with mean differences between devices varying from 12.9 to 20.6% (p > 0.05) throughout the experiment. In the aortic cross-clamp sequence, reduction of values was observed in both devices, with FORE-SIGHT having less pronounces decrease during cross-clamping compared to INVOS (mean differences 1.0-14.7%, p > 0.05), and slower response to reperfusion after declamping (72 to 84% within 1 minute in FORE-SIGHT and 57 to 99% in INVOS). Conclusion Both devices provide similar cnNIRS monitoring applicability at mid-thoracic, upper and lower lumbar levels. INVOS seems to have a more rapid and pronounced response to open SA sequential occlusion and aortic cross-clamping at the lower thoracic level.