The surgical management of acute type A aortic dissection: Current options and future trends

Complete Endovascular Reconstruction of the Canine Ascending Aorta, Aortic Arch, and Supra-Aortic Vessels by Implanting a New Unibody Outer Double-Branched Stent-Graft

PURPOSE

We evaluated the feasibility and safety of using a new unibody outer double-branched stent-graft system to reconstruct the canine ascending aorta, aortic arch, and supra-aortic vessels.

MATERIALS AND METHODS

The outer-branched stent-graft was a unibody design. The branched stent-graft consisted of a main stent-graft and 2 branches. The introducer system included a tri-channel catheter, 2 detachable sleeves, a front fixing device, a constraining wire, and a curved outer sheath. The branched stent-graft was loaded into the introducer system. Ten adult mongrel dogs underwent general anesthesia, and the branched stent-grafts were deployed into the canine ascending aorta, aortic arch, and supra-aortic vessels by the introducer system. All animals were followed up for 3 months. At the end of the follow-up period, computed tomographic angiography (CTA) was performed to observe the patency of the branched stent-grafts.

RESULTS

The mean operation time was 142.7±13.7 minutes. The mean fluoroscopy time was 20.73±2.22 minutes. The mean dosage of contrast agent was 95.9±8.7 mL. During the operation, the tri-channel catheters successfully paralleled the wires in the aorta. All 10 branched stent-grafts were successfully implanted into the canine ascending aorta and aortic arch. There were no symptoms of cerebral embolization and no incision infection during the follow-up period. Computed tomographic angiography and specimens showed that the branched stent-grafts and native vessels were patent, the inner surfaces of the branched stent-grafts were covered by neointima, and there was no retrograde aortic dissection in the ascending aorta.

CONCLUSIONS

This animal research demonstrated that the unibody outer double-branched stent-graft system could be applied to reconstruct the canine ascending aorta, aortic arch, and supra-aortic vessels.

CLINICAL IMPACT

Thoracic endovascular aortic repair has been the main treatment method for aortic aneurysms or dissections involving the descending thoracic aorta. However, the aortic arch and ascending aorta remain the last segments of the aorta without a validated and routinely used endovascular option. In this research, we designed a new unibody outer branched stent-graft system to reconstruct the distal ascending aorta, aortic arch and supra-aortic vessels. The unibody outer branched stent-graft system could be applied to treat aortic pathologies which involve the middle and distal proximal ascending aorta, aortic arch and proximal descending aorta.

Early Prone Position Ventilation in the Efficacy for Severe Hypoxemia and Neurological Complications Following Acute Type A Aortic Dissection (TAAD) Surgery

OBJECTIVE

To analyze the efficacy of early prone position ventilation in the treatment of severe hypoxemia after surgery for acute type A aortic dissection (TAAD).

METHODS

The patients were divided into a control group and a treatment group. Parameters assessed included blood gas analysis indicators [arterial oxygen partial pressure (PaO2).

RESULTS

(1) Blood gas analysis: Before treatment, there was no significant difference in PaO2, SpO2, and OI levels between the two groups; after treatment, the PaO2, SpO2, and OI levels in both groups significantly increased compared to pre-treatment, with a more pronounced improvement in the treatment group than in the control group (p < 0.05). (2) Hemodynamics: Before treatment, there was no significant difference in MAP and HR levels between the two groups; after treatment, the MAP levels increased significantly in both groups compared to pre-treatment, while HR levels decreased significantly, with no significant difference between the groups. (3) Prognosis recovery: MV time, ICU stay, and total hospital stay were significantly lower in the treatment group than in the control group; the 30-day mortality rate was 14.58% in the control group and 12.50% in the treatment group, with no significant difference in 30-day mortality rate between the groups.

CONCLUSION

Early prone position ventilation has shown promising application in the treatment of severe hypoxemia after TAAD surgery. Compared to traditional supine position ventilation, the use of early prone position ventilation can further improve blood gas analysis indicators in patients, and shorten MV time, ICU stay, and total hospital stay, thereby accelerating patient recovery.

The mid-term outcomes of aortic-root repair is not inferior to Bentall procedure in acute type-A aortic dissection

OBJECTIVE

Bentall procedure used to be standard operation for involved aortic root in acute type A aortic dissection (ATAAD). But aortic root repair for preserving valve is still controversial in ATAAD. This study aimed to evaluate the midterm outcomes of aortic root repair by comparing with Bentall approach.

METHODS

A retrospective analysis of 1075 ATAAD patients with aortic root involvement was conducted. The patients were divided into aortic root repair group (n = 447) and Bentall group (n = 628). The propensity score matching analysis (PSMA) was used to adjust the baseline.

RESULTS

The median follow-up was 44 months (interquartile range, 17-65 months; range, 1-130 months). The 30-day mortality in the repair and replacement groups was 15.0 % and 12.9 % (P = 0.327) respectively; the late overall mortality was 15.9 % and 14.0 % (P = 0.394) respectively. The Kaplan-Meier 10-year survival and free-from-reoperation was 86.0 % and 92.5 % respectively in the repair group. After PSMA, the cumulative survival rate [Hazard Ratio (HR) 0.685; 95 % Confidence Interval (CI) 0.457-1.027; P = 0.747]) and reoperation rate (HR 0.308; 95 % CI 0.070-1.355; P = 0.157) was not significantly higher in the repair group than in the Bentall group.

CONCLUSION

The mid-term outcome of aortic root repair is probably not inferior to Bentall procedure. Therefore, root repair is an alternative approach in ATAAD with the advantage of preserving native valve.

Outcomes of two-stage type II hybrid aortic arch repair in elderly patients with acute type A aortic dissection

Acute type A aortic dissection (a-TAAD) is a severe disease characterized by high mortality, which can be fatal in elderly patients. The objective of this study was to investigate the safety and efficacy of two-stage type II hybrid aortic arch repair (HAR) in elderly patients with acute type A aortic dissection (a-TAAD). This was a single-center, retrospective study involving 119 patients with a-TAAD, including 82 males and 37 females, aged 22-81 years old. Eighty-eight patients underwent total aortic arch replacement (TAR) with frozen elephant trunk (FET) implantation (TAR with FET group) and 31 patients underwent two-stage type II HAR (HAR group). Propensity score matching was applied to adjust for preoperative data, and match 25 pairs. The preoperative, perioperative, postoperative and follow-up data were recorded. Fifteen patients died during the perioperative period; 13 cases were in the TAR with FET group and 2 cases were in the HAR group. The age, body mass index, cerebral infarction, renal insufficiency were significantly higher, and the 24-h fluid drainage, the incidence of acute liver injury, acute kidney injury and pulmonary infection were lower in the HAR group (all P < 0.05). Moreover, the mechanical ventilation time, intensive care unit time, hospital stay time were shorter in the HAR group (all P < 0.05). The follow-up period ranged from 12 to 54 months, with 7 deaths (9.3%) in the TAR with FET group and 2 deaths (6.9%) in the HAR group. The true lumen of the aortic arch and the middle descending thoracic aorta were larger and the false lumen thrombosis rates of the middle descending thoracic aorta and renal artery level were higher in the HAR group (all P < 0.05). Two-stage type II HAR is a safe and effective method for the treatment of elderly patients with a-TAAD. It may be a good choice for elderly patients with a-TAAD and comorbidities.

Aortic Dissection

Acute aortic dissection is a highly morbid condition with high mortality that requires emergent surgical evaluation and repair. The intraoperative management of acute aortic dissection requires the anesthesiologist to do far more than administer anesthesia and begins before the patient arrives at the operative theater. High-fidelity communication with the surgeon, knowledge of the surgical plan, knowledge of the anatomy of the dissection, and a nuanced understanding of aortic dissection pathophysiology are all critical aspects of anesthetic management.

Outcomes of acute type A aortic dissection repair: Daytime versus nighttime

Objective

We sought to report our experience of repairing acute type A aortic dissection (ATAAD) over 21 years during in-hours versus out-of-hours before and after the establishment of specialized aortic service and rota.

Methods

A retrospective analysis of all patients who had ATAAD repair between November 1998 and December 2019 in our center. In-hours were defined as 08:00 to 19:59 hours and out of hours were defined as 20:00 to 07:59 hours.

Results

A total of 286 patients underwent repair of ATAAD. Eighty operations took place during the prerota period (43 operations in hours, 37 out of hours) and 206 operations during the specialized rota period (110 in hours, 96 out of hours). There was no difference in 30-day mortality between the in-hours and out-of-hours groups in either the prerota (23.3% vs 32.4%; P = .36) or specialized rota periods (11.6% vs 11.5%; P = .94). Mean number of cases per year increased by 83% between the prerota and specialized rota periods. Thirty-day mortality reduced in both the in-hours (23.3% vs 11.6%) and out-of-hours (32.4% vs 11.5%) groups since introduction of the specialized aortic rota.

Conclusions

Outcomes in repair of ATAAD during in-hours and out-of-hours periods are similar when operated on in a specialized unit with a dedicated aortic team. This emphasizes the current global trend of service centralization without particular attention to time of day to operate on such critical cohort patients.

The ascending aorta and arch in the sights of transcatheter therapy: A time for reappraisal

The ascending aorta and arch have until recently been one of the last bastions of cardiovascular surgery, where life-threatening diseases impose the need for prompt correction and reversal of the impending adverse prognosis. Though a disease where dogmatic recommendations prevail, with upfront surgical intervention in the mind of every physician, type A acute aortic dissection (AAD) is a subject still blurred with many uncertainties. Endovascular intervention for the treatment of type A AAD is rapidly progressing and utilization of transcatheter therapies in the ascending aorta for treating type A AAD has demonstrated technical success in small studies, low early mortality rates, and relatively acceptable aorta-related mortality rates in the long term. These findings strengthen the preponderant role of the endovascular heart surgeon in the management of these procedures, where a combination of wire skill training and surgical proficiency encompassing all technical options available makes it distinctive and resourceful, which provides complete resolution to each multicomponent of this disease in one setting, besides the promptness to repair the inherent complications that will accompany these interventions. Transcatheter procedures and open surgery will coexist side by side and be regarded as complementary rather than competing. Substantial more refinement and technological innovation will be necessary before endovascular repair of type A AAD comes to widespread use, the ideal timespan for cardiovascular surgeons to be involved, and prepared to take on the challenges of leading this new enterprise.

Acute type A aortic dissection in-hours versus out-of-hours: A systematic review and meta-analysis

OBJECTIVE

We sought to compare clinical outcomes in patients with acute type A aortic dissection that undergone surgical repair during in-hours (IH) versus out-of-hours (OOH).

METHODS

An electronic literature search was done till March 2020 to include studies with comparative cohorts of IH versus OOH. Primary outcomes were 30-day mortality, stroke, and reoperation for bleeding; secondary outcomes were acute kidney injury, total hospital stay, and intensive care unit stay.

RESULTS

Six articles with a total of 3744 patients met the inclusion criteria. Mean age was similar, 60 ± 12 versus 60 ± 13 in IH versus OOH (p = .25). Aortic root and total arch replacement were similar in both cohorts, 22% in IH versus 25% in OOH (risk ratio [RR], 1.10; 95% confidence interval [CI: 0.78, 1.55]; p = .58) and 29% in IH versus 32% in OOH (RR, 0.96; 95% CI [0.89, 1.04], p = .37) respectively. Reoperation for bleeding and stroke rate were similar, with 18% in IH versus 23% in OOH (RR, 0.89; 95% CI [0.73, 1.08]; p = .24), and 12% in IH versus 13% in OOH (RR, 0.83; 95% CI [0.66, 1.03]; p = .09) respectively. Thirty-day mortality was significantly lower in IH (RR, 0.81; 95% CI [0.72, 0.90]; p = .0001).

CONCLUSION

There was higher 30-day mortality rate during OOH surgery, yet this difference diminished following sensitivity analysis. There were no significant differences in major postoperative outcomes. Therefore, operating on such cases should be decided on clinical priority without delay.

Acute aortic dissection during pregnancy: Trials and tribulations

BACKGROUND

Type A acute aortic dissection (TAAD) during pregnancy is a life-threatening event for both the mother and the unborn baby. Pregnancy has been recognized as an independent risk factor for TAAD, postulated to be due to physiological changes that cause hyperdynamic circulation. This review seeks to outline the current controversies around this unique group.

METHODS

A comprehensive literature search was carried out across large databases to assimilate relevant papers regarding acute aortic dissection in pregnant women.

RESULTS

The presentation can be atypical in many cases and further concern from clinicians of fetal radiation exposure can result in missed or delayed diagnoses. Investigation via the quickest form of imaging, whether computed tomography, magnetic resonance imaging, or transesophageal echocardiography, should be carried out promptly due to the high risk of mortality. Surgical management of TAAD in pregnancy revolves primarily around the decision to deliver the fetus concomitantly or to perform the aortic repair with the fetus in utero.

CONCLUSIONS

Management of this group includes rapid and dynamic assessment without delay. From conception to postpartum, there are multiple stages in which to manage these women. Challenges in carrying out management in the form of operative techniques and cardiopulmonary bypass place the fetus at risk and must be approached with caution, particularly as there is little evidence-base for many of these decisions. Further research into reducing maternal and fetal mortality is necessary.