Shintaro Katahira1, Shunsuke Kawamoto1, Naoki Masaki1, Yukihiro Hayatsu1, Tadao Matsunaga2, Yoichi Haga3, Yoshikatsu Saiki1. 1. Division of Cardiovascular Surgery, Tohoku University Graduate School of Medicine, Seiryocho, Aoba-ku, Sendai, Japan. 2. Micro System Integration Center, Tohoku University, Miyagi, Aoba, Aramaki Aoba-ku, Sendai, Japan. 3. Tohoku University Graduate School of Biomedical Engineering, Aoba, Aramaki Aoba-ku, Sendai, Japan.
Abstract
OBJECTIVES: Secondary aorto-oesophageal fistula is a rare, lethal complication occurring after thoracic endovascular aneurysmal repair. The cause of secondary aorto-oesophageal fistula is unknown, but a reduction in local oesophageal mucosal blood flow (OMBF) may be a basis for such a devastating sequela. Our study aims to develop a novel blood flow sensor probe to detect changes in OMBF after thoracic stent graft implantation in an experimental swine model. METHODS: A novel laser Doppler flowmetry sensor probe incorporating an optical fibre sensor within a nasogastric tube was developed using microelectromechanical system technology. OMBF was measured at various levels using this sensor probe, to test its feasibility before and after thoracic endovascular stent graft implantation covering Th4-Th8 vertebral levels in 6 swine. RESULTS: In the middle oesophagus (Th5-Th7), where the aorta was covered with a stent graft, the measured OMBFs were significantly decreased after thoracic endovascular stent graft implantation than those of baseline (8.6 ± 2.7 vs 18.4 ± 7.9 ml/min/100 g, P < 0.0001), followed by a plateau period for at least 2 h after stent grafting (8.7 ± 3.3 ml/min/100 g, P < 0.0001 vs baseline). OMBFs in the upper (Th1-Th3) and lower (Th9-Th11) oesophagus, where the aorta was not covered with a stent graft, were unaffected by thoracic endovascular stent grafting. CONCLUSIONS: The novel laser Doppler flowmetry sensor probe was useful to monitor precise changes of OMBF in a swine model, demonstrating a significant reduction in OMBF after thoracic endovascular stent graft implantation.
OBJECTIVES: Secondary aorto-oesophageal fistula is a rare, lethal complication occurring after thoracic endovascular aneurysmal repair. The cause of secondary aorto-oesophageal fistula is unknown, but a reduction in local oesophageal mucosal blood flow (OMBF) may be a basis for such a devastating sequela. Our study aims to develop a novel blood flow sensor probe to detect changes in OMBF after thoracic stent graft implantation in an experimental swine model. METHODS: A novel laser Doppler flowmetry sensor probe incorporating an optical fibre sensor within a nasogastric tube was developed using microelectromechanical system technology. OMBF was measured at various levels using this sensor probe, to test its feasibility before and after thoracic endovascular stent graft implantation covering Th4-Th8 vertebral levels in 6 swine. RESULTS: In the middle oesophagus (Th5-Th7), where the aorta was covered with a stent graft, the measured OMBFs were significantly decreased after thoracic endovascular stent graft implantation than those of baseline (8.6 ± 2.7 vs 18.4 ± 7.9 ml/min/100 g, P < 0.0001), followed by a plateau period for at least 2 h after stent grafting (8.7 ± 3.3 ml/min/100 g, P < 0.0001 vs baseline). OMBFs in the upper (Th1-Th3) and lower (Th9-Th11) oesophagus, where the aorta was not covered with a stent graft, were unaffected by thoracic endovascular stent grafting. CONCLUSIONS: The novel laser Doppler flowmetry sensor probe was useful to monitor precise changes of OMBF in a swine model, demonstrating a significant reduction in OMBF after thoracic endovascular stent graft implantation.