154 T. Takeichi et al.: J Extra Corpor Technol 2025, 57, 153--159
Figure 1.( a) Aortic contrast-enhanced CT scan indicates a DAA with malperfusion of the left lower limb and an entry tear in the ascending aorta.( b) LCCA and LSCA show no abnormalities.( b, c) The true lumen from the BCA to the RCCA is narrowed by the false lumen. CT: Computed tomography; DAA: Dissecting aortic aneurysm; LCCA: Left common carotid artery; LSCA: Left subclavian artery; BCA: Brachiocephalic artery; RCCA: Right common carotid artery.
Following induction of general anesthesia, bilateral radial arterial and central venous catheterizations were performed for three-site pressure monitoring. Intraoperative neurovascular and lower-limb perfusion was assessed using near-infrared spectroscopic oximetry( NIRO 200, Hamamatsu Photonics, Hamamatsu, Japan). The mechanism of NIRO-200NX is shown in Figures 2a--2c. Despite the significant narrowing of the true lumen at the BCA, bilateral radial pressures were maintained between 106 / 43 and 113 / 44 mmHg. Cerebral TOI values remained stable at 88--90 %, with no interhemispheric differences. However, TOI in the right lower limb was 75 %, while it was markedly reduced to 35 % in the left lower limb, reflecting malperfusion( Figs. 3a and 3b). Arterial lactate levels were 1.5 mmol / L, indicating no evidence of metabolic derangement.
Given the severity of malperfusion, we opted for cannulation of the right femoral artery( FA) and the ascending aorta for CPB. A median sternotomy was performed, and intraoperative echocardiography confirmed the characteristics of the ascending aorta. However, due to extreme narrowing of the true lumen and significant mobility of the intimal flap, ascending aortic cannulation proved technically challenging. Also, regarding axillary artery cannulation, the true lumen was extremely narrowing due to dissection. Consequently, CPB was initiated via right FA arterial cannulation( 18Fr PCKC-A, MERA, Tokyo, Japan) and bicaval venous cannulation( 26Fr INKN-L, Medtronic, USA), employing the Heart Assist System III( HAS III, Mera Corporation, Tokyo, Japan). The extracorporeal circuit composition was that centrifugal pump( MERA Centrifugal Pump HCF-MP23, SENKO MEDICAL INSTRUMENT, Inc., Tokyo, Japan), FX-25 oxygenator
( Terumo Corporation, Japan) were utilized. The arterial tubing size was 3 / 8 inch. A CDI Blood Parameter Monitoring System 500( Terumo, Tokyo, Japan) was recalibrated every 60 min, and an arterial blood gas sample was also checked every 60 min. Alpha STAT was utilized. CPB was commenced with gradual flow increments. After achieving the total flow, we watched for 1 min to confirm no change parameters such as both mABP and TOI change rates. The patient was cooled to a target rectal temperature of 26 ° C. During the early CPB phase, mABP and TOI change rates showed no significant alterations( Figs. 3 and 4). Cardiac index( CI) was maintained at 2.6--3.0 L / min / m 2. TheTOIandDO 2 Hb in the left lower limb gradually improved( Fig. 3b). However, approximately 15 min after CPB initiation, a significant bilateral disparity of 15 mmHg in radial arterial mABP was observed. Simultaneously, cerebral TOI and DO 2 Hb began to decline( Figs. 3 and 4). With rectal and tympanic temperatures around 32--34 ° C, circulatory arrest was initiated at 30 ° C. To mitigate malperfusion, we transitioned from NPF to PF. The pulse pressure of left radial mABP ranged from 20 to 25 mmHg( Fig. 5), with PF settings of 63 bpm heart rate, 100 % base flow, and 50 % duration. Arterial lactate levels remained stable at 1.1 mmol / L.
The transition to PF required approximately 3 min, during which the right radial mABP dropped to 29 mmHg before gradual recovery, accompanied by improvements in cerebral TOI( Figs. 3 and 4). Cerebral TOI nadirs were 85 %( left) and 67 %( right), with maximum declines in both cerebral TOI of �15 %, DO 2 Hb of �6 lmol / L( right) and �8 lmol / L( left). Concurrently, deoxygenated hemoglobin( DHHb) levels showed a downward trend.