With increased life span, cardiovascular disease, including AAAD, has seriously harmed the overall health of older adults. Older age is generally considered as a risk factor for surgical intervention for AAAD. The hospital mortality due to surgical repair for AAAD in older adults is high in some reports.8,9 Despite advances in surgical techniques, it continues to be a frustrating challenge for cardiac surgeons.
Reports of aortic valve replacement, even aortic arch surgery, utilizing a PUS approach have been published.10–14 However, there are few reports regarding the use of a PUS during AAAD in older adults. Although the association between surgical volume and outcomes for AAAD have not been demonstrated, our group has experienced more than 1000 open surgeries for modified triple-branched stent graft in AAAD since 2012, and we have established an efficient process of diagnosis and treatment of AAAD. Based on these studies, since 2017 we have adopted the PUS approach for extensive arch repair for AAAD in older adults. The PUS approach has proven to be a feasible and safe approach for aortic valve replacement and aortic root surgery. For example, Inoue and colleagues published initial results of 15 cases of total arch replacement utilizing PUS. In their procedure, they used both an “L” shape and “T” shape for PUS.13 The “L” shape utilized in our study provided excellent exposure, with no conversion to FS required. Interestingly, among our patients, the PUS group presented shorter Cardiopulmonary bypass time, cross-clamp time and shorter selective cerebral perfusion time than the FS group. It is possible surgical skill of the performing surgeon may improve with the increase in surgical volume.
In our cohort, the results are similar to those reported in the literature, ranging from 13.3–45.6% in older adults patients with AAAD in previous studies.8–9,15−18 Our study demonstrated that LVEF < 50% and malperfusion syndromes were significant risk factors of early death in older adult surgical patients with AAAD.19–22 Dissection-related factors could lead to a progressive worsening of hemodynamic instability and organ function. Likely, these patients were in left ventricular dysfunction or multiple organ failure after surgery, eventually leading to death. The treatment strategy for these patients was to establish cardiopulmonary bypass as soon as possible, securing true lumen flow and restoring organ perfusion.
Prolonged operation or cardiopulmonary bypass time may be harmful for older adult patients. Several research institutions recommend surgery with only ascending aorta replacement for older adult patients with AAAD.8, 23–25 However, our novel technique could simplify extensive arch repair, reducing surgery time. Our results demonstrated that cardiopulmonary bypass time, cross-clamp time, selective cerebral perfusion time were 133.0 minutes, 44.0 minutes, and 11.0 minutes in the PUS group. Previous studies have reported these variables ranged from 214 to 223 minutes, 125 to 146 minutes, and 54 to 69 minutes, respectively.14,26 It is possible that our novel technique and experience of a large surgical volume of AAAD lead to shorter surgical times.
Several studies have demonstrated that compared with a full sternotomy, PUS provided earlier extubation, less blood loss, less blood transfusion, and less incisional pain.27,28 In our study, the PUS group had a less mediastinal drainage and red blood cell transfusion. In the multivariate model, the PUS approach contributed to shorter ventilator-supporting time compared with the FS group. The PUS approach reduced surgical trauma, and maintained chest stability, which contributed to the recovery of postoperative respiratory function. Furthermore, PUS offers a rapid postoperative recovery and cosmetic advantages.
The hypertension, malperfusion syndromes and cardiopulmonary bypass time both leaded to longer ventilator-supporting time and post-operative ICU stay time. The hypertension may be the most common predisposing factor for AAAD. A sharp rise in blood pressure and tearing of aorta could lead to a systemic inflammatory response. And during long CPB time, the exposure of blood to abnormal surfaces may induce a systemic inflammatory response. All these factors could contribute to acute respiratory distress syndrome, which prolonged ventilator-supporting time and post-operative ICU stay time.
The significant limitation of the study is that it is a retrospective study, and has a lack of statistical power due to small sample sizes. A prospective randomized controlled trial is required to evaluate this result.