Establishing an efficient and safe cardiopulmonary bypass to maintain adequate systemic perfusion is essential in ATAAD surgery. The optimal cannulation site should meet the physiology needs of important organs in the whole body, provide a clean surgical field and reduce the complications associated with cannulation. According to a survey across European cardiac centers13: In both acute and chronic settings, the right subclavian–axillary approach is the favourite site for cannulation (54 and 48%, respectively). The second favoured choice differs depending on the clinical presentation: for acute conditions, the femoral approach is preferred, while, for chronic conditions, the ascending aorta is preferred, both accounting for 28% of the cases. Femoral artery cannulation can be used quickly and provide enough perfusion flow for whole body, therefore, it is preferred in hemodynamic unstable patients instead of axillary artery cannulation which may occasionally be too time-consuming14, 15. However, femoral artery cannulation hast a high rate of false lumen perfusion, limb malperfusion and cerebral complications a due to a retrograde flow16. In our center, femoral artery cannulation was used mostly in the unstable haemodynamics patients (97/551, 17.6%). As an alternative cannulation strategy, axillary artery cannulation has been advocated by many surgeons17. The collateral circulation of neck and shoulder is rich, and the distal limbs are not easy to be ischemic necrosis and involved by atherosclerosis and dissection, which can effectively avoid retrograde embolization, avoid the expansion of dissection range and facilitate antegrade selective cerebral perfusion14, 18. Several researches had shown that RAC can reduce intraoperative and postoperative mortality, lower rates of cerebral complications and malperfusion and fewer reoperation rates which could improve both short-term and long-term outcomes of ATAAD compared with central aortic or femoral artery cannulation19–21. However, the diameter of the axillary artery is smaller compared to femoral artery, single axillary artery cannulation may lead to end-organ malperfusion in some ATAAD patients.
Double arterial (axillary artery combined with femoral artery) cannulation has reliable circulatory support which provides anterograde and retrograde blood flow at the same time to achieve the best systemic perfusion strategy, results of DAC strategy are scarcely published with limited cases available. Minatoya5 reported a group of 88 AAD patients used DAC, the results showed that DAC approach was associated with a low mortality even in AAD patients with malperfusion. Recently, Lin et all 21 reported that ATAAD patients who underwent DAC had lower in-hospital mortality and lower incidence of malperfusion-related complications than those who underwent single arterial cannulation, three-year cumulative survival was also better in DAC group. However, we didn’t find any difference on in-hospital mortality and follow-up survival between DAC and RAC group in our 431 patients’ study. Our results were similar to the study from Kusadokoro et all. 22, they found that DAC had acceptable early and long-term follow-up results for both planned and unplanned (rescue) ATAAD surgery.
It arouses curiosity whether cannulation strategies differ in terms of perioperative parameters in ATAAD patients. Kusadokoro et all.22 reported that they preferred DAC in patients with true lumen stenosis and perioperative leg malperfusion. However, even with propensity score matching, the trend that DAC group were younger and with lower incidence of perioperative shock was still seen. This trend was similar to our cannulation strategy, we preferred the DAC strategy in younger patients with perioperative limb and visceral malperfusion. We consider that the axillary artery combined with femoral artery may improve true lumen narrowing and perfusion status which may be benefit for organ protection.
Cerebrovascular injury is one of the major causes of morbidity and mortality of ATAAD surgery and cannulation with femoral artery was recognized as a risk factor for inferior outcome23, 24. In our study, we found that the incidence of postoperative stroke was higher in DAC group than RAC group due to addition of femoral artery. While the incidence of postoperative stroke in DAC group (5.9%) and RAC group (0%) were much lower than reports of German Registry for Acute Aortic Dissection Type A (GERAADA) 25. The lower incidence of postoperative cerebrovascular injury in both DAC and RAC might be associated with adequate cerebral perfusion and cerebral monitoring using the bilateral cerebral oxygen.
AKI is another important early complication following ATAAD-repair that increases patients’ mortality, which was reported ranging from 40–55% 26. In our study, the incidence of AKI was 29.0% in all patients which was lower than what reported in literature. Moreover, the incidence of AKI was much lower in DAC group than RAC (26.7% vs. 37.8%, P = 0.039). Similar to previous studies that age, obesity, hypertension and prolonged CPB times were independent risk factors for postoperative AKI 27, 28, we found that patients in DAC group were younger than RAC group. In addition, the duration of mechanical ventilation was shorter in DAC group (42.39 ± 46.03 h) than RAC group (56.43 ± 57.01 h) which demonstrated our previous findings. Wang Z and his colleagues in our center reported that shorten mechanical ventilation duration as much as possible might help reducing postoperative AKI incidence 29. The relationship between prolonged mechanical ventilation and postoperative AKI may be explained by three possible mechanisms: (I) through effects on arterial blood gases; (II) through an effect on systemic and renal blood flow; (III) by triggering a pulmonary inflammatory reaction induced during biotrauma that further mediates systemic changes 30. We made propensity score matching (PSM) to avoid the bias of age and preoperative conditions, the incidence of AKI was still much lower in DAC group than RAC group after PSM (24.7% vs. 40.3%, P = 0.015). To confirm what we found, we compared intraoperative blood gas results and cardiopulmonary bypass parameters in patients who underwent total arch replacement (TAR) and stented elephant trunk (SET). In this cohort, patients in DAC group had more intraoperative urine volume than RAC group (P = 0.05) which may indicate that DAC strategy could provide better kidney perfusion during ATAAD surgery. Furthermore, the cooling time and rewarming time were all shorter in DAC group than RAC group, this may be explained that DAC could introduce both forward perfusion and reverse perfusion to achieve the best systemic perfusion effect, and the two-way blood flow has better systemic perfusion stability. Based on what we found in this study, we thought that DAC could reduce the incidence of AKI by providing better kidney perfusion.