Optimal temperature management in aortic arch surgery: A systematic review and network meta-analysis

OBJECTIVES

New temperature management concepts of moderate and mild hypothermic circulatory arrest during aortic arch surgery have gained weight over profound cooling. Comparisons of all temperature levels have rarely been performed. We performed direct and indirect comparisons of deep hypothermic circulatory arrest (DHCA) (≤20°C), moderate hypothermic circulatory arrest (MHCA) (20.1-25°C), and mild hypothermic circulatory arrest (mild HCA) (≥25.1°C) in a network meta-analysis.

METHODS

The literature was systematically searched for all papers published through February 2022 reporting on clinical outcomes after aortic arch surgery utilizing DHCA, MHCA and mild HCA. The primary outcome was operative mortality. The secondary outcomes were postoperative stroke and acute kidney failure (AKI).

RESULTS

A total of 34 studies were included, with a total of 12,370 patients. DHCA was associated with significantly higher postoperative incidence of stroke when compared with MHCA (odds ratio [OR], 1.46, 95% confidence interval [CI], 1.19-1.78) and mild HCA: (OR, 1.50, 95% CI, 1.14-1.98). Furthermore, DHCA and MHCA were associated with higher operative mortality when compared with mild HCA (OR 1.71, 95% CI, 1.23-2.39 and OR 1.50, 95% CI, 1.12-2.00, respectively). Separate analysis of randomized and propensity score matched studies showed sustained increased risk of stroke with DHCA in contrast to MHCA and mild HCA (OR, 1.61, 95% CI, 1.18-2.20, p value = .0029 and OR, 1.74, 95% CI, 1.09-2.77, p value = .019).

CONCLUSIONS

In the included studies, the moderate to mild hypothermia strategies were associated with decreased operative mortality and the risk of postoperative stroke. Large-scale prospective studies are warranted to further explore appropriate temperature management for the treatment of aortic arch pathologies.

Virtual Reality in the Preoperative Planning of Adult Aortic Surgery: A Feasibility Study

Background: Complex aortic anatomy needs careful preoperative planning in which a patient-tailored approach with novel immersive techniques could serve as a valuable addition to current preoperative imaging. This pilot study aimed to investigate the technical feasibility of virtual reality (VR) as an additional imaging tool for preoperative planning in ascending aortic surgery. Methods: Ten cardiothoracic surgeons were presented with six patients who had each undergone a recent repair of the ascending aorta. Two-dimensional computed tomography images of each patient were assessed prior to the VR session. After three-dimensional (3D) VR rendering and 3D segmentation of the ascending aorta and aortic arch, the reconstructions were analyzed by each surgeon in VR via a head-mounted display. Each cardiothoracic surgeon completed a questionnaire after each planning procedure. The results of their assessments were compared to the performed operations. The primary endpoint of the present study was a change of surgical approach from open to clamped distal anastomosis, and vice versa. Results: Compared with conventional imaging, 80% of surgeons found that VR prepared them better for surgery. In 33% of cases (two out of six), the preoperative decision was adjusted due to the 3D VR-based evaluation of the anatomy. Surgeons rated CardioVR usefulness, user-friendliness, and satisfaction with median scores of 3.8 (IQR: 3.5–4.1), 4.2 (IQR: 3.8–4.6,) and 4.1 (IQR: 3.8–4.7) on a five-point Likert scale, respectively. Conclusions: Three-dimensional VR imaging was associated with improved anatomical understanding among surgeons and could be helpful in the future preoperative planning of ascending aortic surgery.

OUP accepted manuscript

Consensus regarding optimal cerebral protection strategy in aortic arch surgery is lacking. We therefore performed a systematic review and meta-analysis to assess outcome differences between unilateral antegrade cerebral perfusion (ACP), bilateral ACP, retrograde cerebral perfusion (RCP) and deep hypothermic circulatory arrest (DHCA). A systematic literature search was performed in Embase, Medline, Web of Science, Cochrane and Google Scholar for all papers published till February 2021 reporting on early clinical outcome after aortic arch surgery utilizing either unilateral, bilateral ACP, RCP or DHCA. The primary outcome was operative mortality. Other key secondary endpoints were occurrence of postoperative disabling stroke, paraplegia, renal and respiratory failure. Pooled outcome risks were estimated using random-effects models. A total of 222 studies were included with a total of 43 720 patients. Pooled postoperative mortality in unilateral ACP group was 6.6% [95% confidence interval (CI) 5.3–8.1%], 9.1% (95% CI 7.9–10.4%), 7.8% (95% CI 5.6–10.7%), 9.2% (95% CI 6.7–12.7%) in bilateral ACP, RCP and DHCA groups, respectively. The incidence of postoperative disabling stroke was 4.8% (95% CI 3.8–6.1%) in the unilateral ACP group, 7.3% (95% CI 6.2–8.5%) in bilateral ACP, 6.4% (95% CI 4.4–9.1%) in RCP and 6.3% (95% CI 4.4–9.1%) in DHCA subgroups. The present meta-analysis summarizes the clinical outcomes of different cerebral protection techniques that have been used in clinical practice over the last decades. These outcomes may be used in advanced microsimulation model. These findings need to be placed in the context of the underlying aortic disease, the extent of the aortic disease and other comorbidities.

Prospero registration number: CRD42021246372

METC: MEC-2019-0825

Initial clinical experience with minimally invasive surgical aortic valve replacement

BACKGROUND

The ministernotomy approach is increasingly used in aortic valve surgery. However, the advantages are still a matter of discussion. The aim of this study was to compare the postoperative outcome in patients undergoing elective aortic valve operation, either through mini-sternotomy or conventional sternotomy.

METHODS

We included 317 patients who were treated for their aortic valve, 63 patients underwent a minimally invasive aortic valve replacement (mini-AVR) and 254 patients underwent a full-sternotomy AVR. Patients with endocarditis, those who underwent previous cardiac surgery and those who required a concomitant procedure were excluded from the analysis. The method of matching weights according to propensity score was used to adjust for differences between the two treatment groups, and outcomes were compared.

RESULTS

The mediastinal drainage was significantly lower at 6, 24 hours and total after mini-AVR procedure than after full-sternotomy AVR (median: 373 vs. 499 mL, P<0.001). However, the number of patients receiving packed red blood cells transfusion was similar. Overall, the hospital mortality was lower in the full-sternotomy group, 0% vs. 3.2%, P=0.039. No difference was found in the median hospital length of stay, perioperative myocardial infarction, postoperative incidence of new pacemaker implantation, stroke, prolonged mechanical ventilation and mediastinitis. No patients in the mini-AVR group experienced paravalvular leakage. Midterm survival resulted in no difference between the treatment groups at 4-year (90.5% vs. 95.2%), P=0.75.

CONCLUSIONS

Although the minimally invasive surgery for AVR may increasingly be applied, our initial experience calls for a careful approach of adapting this procedure.

Outcomes of different aortic arch replacement techniques

Background

Consensus on the best treatment for aortic arch pathology is unresolved due to an emerging variety of procedures. We aimed to compare the outcomes of two major techniques for open aortic arch replacement involving the supra‐aortic branches and to identify the risk factors for specific adverse events.

Methods

Between 1974 and 2017, 172 patients were treated with either the en bloc (island, n = 59; 34.3%) or branched graft technique (n = 113, 65.7%). Most of the patients were treated in an emergent/urgent setting (52.4%).

Results

Patients who underwent the en bloc procedure had significantly shorter cardiopulmonary bypass (median: 241 vs 271 minutes, P = .041) and aortic cross clamp times (median: 124 vs 168 minutes, P = .005) than patients who underwent the separate graft technique. Overall, the hospital mortality was lower in the en bloc group, 8.5% vs 19.5%, although the difference was not significant (P = .077). No difference was found in the survival between the separate graft and en bloc groups at 1 (77.0 vs 86.3%), 5 (67.7 vs 66.3%) and 10 years (42.4 vs 51.3%), (P = .63). The postoperative stroke rate was comparable between the en bloc and separate graft cohorts (14.3 vs 19.6%, P = .52). Diabetics and those who underwent an elephant trunk procedure were at a higher risk for reintervention.

Conclusions

The separate graft technique, which is more common today, showed no difference from the en bloc technique with regard to hospital mortality and morbidity. Furthermore, the late survival and reintervention rates were similar after both procedures.