Despite recent improvements in the results of acute type A aortic dissection (ATAAD) repair, the optimal initial cannulation site for establishing cardiopulmonary bypass remains a topic of debate. For example, the German Registry for Acute Aortic Dissection Type A (GERAADA) indicated that the choice of cannulation site was not a significant determinant of mortality [1]. In that multicenter study, which included 2,137 ATAAD patients, various cannulation sites did not impact the intraoperative death rate, except for aortic arch cannulation, which was associated with a higher mortality risk than other sites (odds ratio [OR], 1.93; 95% confidence interval [CI], 1.12–3.27). Conversely, a meta-analysis evaluating 793 patients across 8 publications found that axillary artery cannulation reduced the risk of in-hospital mortality (OR, 0.54; 95% CI, 0.38–0.82) compared with femoral arterial cannulation [2]. Meanwhile, some groups have suggested that sono-guided direct ascending aorta cannulation into the true lumen could be an effective method for initiating cardiopulmonary bypass [3]. These conundrums may primarily be attributed to the diverse conditions of aortic dissection (AD) flap and the communications between the true and false lumens (Fig. 1).

Figure 1. Difficulties in cannulation for acute type A aortic dissection repair. (A) Axillary, innominate, direct ascending, and retrograde right femoral artery cannulations are available. (B) Retrograde femoral artery access is not recommended. (C) Antegrade axillary or innominate artery cannulation is not recommended.

In the journal, Yoon et al. [4] analyzed 146 cases of ATAAD repair performed between 2008 and 2023, comparing antegrade (n=32) and retrograde (n=114) arterial perfusion methods used during cardiopulmonary bypass during the ATAAD repair. The total surgical time (356 minutes versus 443 minutes, p<0.001) and intensive care unit (ICU) stay (3±5 days versus 5±16 days, p=0.013) were significantly different between the antegrade and retrograde groups. There were no significant differences in the 30-day mortality and postoperative stroke outcomes. The authors concluded that “surgeons should contemplate an appropriate cannulation strategy for each patient, rather than strictly adhering to a specific approach in AD surgery.”

The authors are to be congratulated for their timely evaluation of this significant issue. Although the study was limited by a small number of subjects, the authors made a considerable effort to provide a detailed baseline profile for both groups. However, readers should exercise caution when interpreting the study’s result, which suggests that the antegrade group experienced shorter operation times and ICU stays compared to the retrograde group, as the evaluation may be subject to a significant degree of selection bias. Nonetheless, an important takeaway from this study is the critical role of selecting an appropriate cannulation site based on the patient’s aortic dissection condition, whether the cardiopulmonary bypass is performed in an antegrade or retrograde manner.

ATAAD poses significant risks of perioperative complications, including brain, bowel, or limb ischemia, as well as aortic rupture. Survival rates for patients with ATAAD complicated by mesenteric ischemia are particularly poor. According to the International Registry of Acute Dissection (IRAD), hospital mortality for ATAAD with concurrent mesenteric malperfusion exceeds 60% [5]. Hence, some centers opt for an initial endovascular fenestration/stenting procedure, followed by open aortic repair once metabolic acidosis has been resolved [6]. The mortality rate associated with this approach (30%) appears to be lower than that of medical treatment alone (95%) or immediate open aortic repair (42%), as reported in the IRAD data. These findings underscore the importance of promptly restoring adequate perfusion to hemodynamically compromised vital organs to improve clinical outcomes in ATAAD. In light of this, selecting a cannulation site for open ATAAD repair should take into account a comprehensive assessment of the vascular conditions, including the inflow to vital organs, the location of the intimal tear, the configuration of the dissecting flap, and the extent of the aortic repair required. Therefore, a judicious and flexible strategy tailored to the individual patient’s aortic anatomy is essential for determining the optimal cannulation site.

Author contributions

The manuscript was written by WKK under the supervision of SWS and KJY.

Conflict of interest

Suk-Won Song serves as an associate editor of the Journal of Chest Surgery, but he has no role in the decision to publish the present manuscript. Except for that, no potential conflict of interest exists.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.