Type A aortic dissection: optimal annual case volume for surgery

BACKGROUND AND AIMS

The current study proposes a novel volume-outcome (V-O) meta-analytical approach to determine the optimal annual hospital case volume threshold for cardiovascular interventions in need of centralization. This novel method is applied to surgery for acute type A aortic dissection (ATAAD) as an illustrative example.

METHODS

A systematic search was applied to three electronic databases (1 January 2012 to 29 March 2023). The primary outcome was early mortality in relation to annual hospital case volume. Data were presented by volume quartiles (Qs). Restricted cubic splines were used to demonstrate the V-O relation, and the elbow method was applied to determine the optimal case volume. For clinical interpretation, numbers needed to treat (NNTs) were calculated.

RESULTS

One hundred and forty studies were included, comprising 38 276 patients. A significant non-linear V-O effect was observed (P < .001), with a notable between-quartile difference in early mortality rate [10.3% (Q4) vs. 16.2% (Q1)]. The optimal annual case volume was determined at 38 cases/year [95% confidence interval (CI) 37-40 cases/year, NNT to save a life in a centre with the optimal volume vs. 10 cases/year = 21]. More pronounced between-quartile survival differences were observed for long-term survival [10-year survival (Q4) 69% vs. (Q1) 51%, P < .01, adjusted hazard ratio 0.83, 95% CI 0.75-0.91 per quartile, NNT to save a life in a high-volume (Q4) vs. low-volume centre (Q1) = 6].

CONCLUSIONS

Using this novel approach, the optimal hospital case volume threshold was statistically determined. Centralization of ATAAD care to high-volume centres may lead to improved outcomes. This method can be applied to various other cardiovascular procedures requiring centralization.

Short- and long-term results of total arch replacement: Comparison between island and debranching techniques

OBJECTIVE

The 2 most acceptable techniques for reimplantation of the supra-aortic vessels in total arch replacement include the branched graft technique (debranching) or en bloc technique (island). We aim to review our experience with total arch replacement and report short- and long-term outcomes from a high-volume center dedicated to surgery for the thoracic aorta.

METHODS

The aortic surgery database was queried to identify all consecutive patients undergoing total arch replacement between 1997 and 2022. Of the 426 patients who underwent total arch replacement, 303 (71%) received the island technique and 123 (29%) received the debranching approach. Operative and long-term outcomes were compared using multivariable models.

RESULTS

The debranching group was younger (64 ± 14 years vs 69 ± 12 years, P = .001), had undergone more previous cardiac operations (54.5% vs 27.4%, P < .001), and had more connective tissue disorder (20.3% vs 4.6%, P < .001). The debranching approach was associated with longer total circulatory arrest time (47 ± 15 minutes vs 37 ± 10 minutes, P < .001) and cardiac ischemic time (116 ± 41 minutes vs 100 ± 37 minutes, P < .001). More patients in the debranching group received blood products intraoperatively or postoperatively (56.1% vs 42.9%, P = .018). All other early outcomes did not differ between groups. Overall operative mortality was 1.4% (2.4% vs 1%, P = .486); the incidence of major postoperative complications was 6.3% (5.7% vs 6.6%, P = .897). Ten-year survival was 80% (78% vs 80.9%, log-rank P = .356). Multivariable Cox regression analysis demonstrated that neither surgical approach was associated with survival advantage (hazard ratio, 1.18; 0.73-1.89; P = .495).

CONCLUSIONS

Debranching requires a longer operative time, with similar early and long-term outcomes. Preoperative comorbidity, not surgical technique, predicts major adverse events and long-term survival.

Modified "in situ" arch replacement with an integrative frozen elephant trunk device for acute type A aortic dissection

Background

Total arch replacement (TAR) and frozen elephant trunk (FET) has been proposed as the primary arch repair method for acute type A aortic dissection (aTAAD). We introduce a modified “in situ” arch replacement with an integrative FET device for aTAAD.

Methods

From January 2018 to December 2019, 507 aTAAD patients from Nanjing Drum Tower Hospital received surgical therapy; among them, 57 patients with modified island total arch replacement (MiTAR) and 138 patients with TAR were enrolled. Marfan syndrome, primary intimal tears located in the large curve of aortic arch +/− or supra-arch vessels and dilated aortic arch (≥45 mm) were contraindications for MiTAR. MiTAR involves two steps: first, insert a FET device into the descending aorta during the hypothermic circulation arrest period; second, anastomose the remaining “island” arch with the prosthetic vessel and the proximal part of the FET.

Results

MiTAR patients were older than those receiving TAR (52.1 vs. 48.9 years; P=0.078), but their baseline demographics and manifestations of organ ischaemia were nearly the same. The times of cardiopulmonary bypass (CPB), aortic clamp and hypothermic circulation arrest were significantly shorter with MiTAR (209.3 vs. 267.1 minutes, P=0.000; 147.9 vs. 190.0 minutes, P=0.000; 34.0 vs. 39.4 minutes, P=0.003, respectively). The volumes of intraoperative transfusions of red blood cells (RBCs), fresh frozen plasma (FFP), platelets and cryoprecipitates were significantly lower in MiTAR (5.9 vs. 8.5 units, P=0.000; 758.3 vs. 930.4, P=0.000; 12.5 vs. 17.5 mL, P=0.000; 9.4 vs. 16.6 units, P=0.000). The 30-day mortality was 7.0% (4/57) for MiTAR and 11.6% (16/138) for TAR. One patient died and no patient received reintervention during the follow-up period, while the size of several levels of aorta showed a decreasing trend.

Conclusions

MiTAR is a simplified approach to TAR that reduces the surgical trauma while achieving aortic reshaping effects.

En Bloc Arch Reconstruction With the Frozen Elephant Trunk Technique for Acute Type a Aortic Dissection

Objective: The study objective was to evaluate the effect of en bloc arch reconstruction with frozen elephant trunk (FET) technique for acute type A aortic dissection.

Methods: 41 patients with acute Stanford type A dissection underwent en bloc arch reconstruction combined with FET implantation between April 2018 and August 2020. The mean age of the patients was 46 ± 13 years, and 9 patients were female. One patient had Marfan syndrome. Six patients had pericardial tamponade, 9 had pleural effusion, 5 had transient cerebral ischemic attack, and 3 had chronic kidney disease.

Results: The hospital mortality rate was 9.8% (4 patients). 2 (4.9%) patients had stroke, 23 (56.1%) had acute kidney injury, and 5 (12.2%) had renal failure requiring hemodialysis. During follow-up, the rate of complete false lumen thrombosis was 91.6% (33/36) around the FET, 69.4% (25/36) at the diaphragmatic level, and 27.8% (10/36) at the superior mesenteric artery level. The true lumen diameter at the same three levels of the descending aorta increased significantly while the false lumen diameter reduced at the two levels: pulmonary bifurcation and the diaphragm. The 1-, 2-and 3-year actuarial survival rates were 90.2% [95% confidence interval (CI), 81.2–99.2], 84.2% (95% CI, 70.1–98.3) and 70.2% (95% CI, 42.2–98), respectively.

Conclusions: In patients with acute type A dissection, en bloc arch reconstruction with FET technique appeared to be feasible and effective with early clinical follow-up results. Future studies including a large sample size and long-term follow-up are required to evaluate the efficacy.

Frozen elephant trunk technique with different proximal landing zone for aortic dissection

OBJECTIVES

The objective of the study was to evaluate early and midterm outcomes after the frozen elephant trunk (FET) procedure with different proximal landing zones in patients with aortic dissection.

METHODS

Forty-four patients with type A and type B aortic dissection that extended down to the abdominal aorta were enrolled in the study. All of the patients had the FET procedure. The patients were divided in 2 groups according to the level of the proximal landing zone: the zone 2 (Z2) group and zone 3 (Z3) group. Early and midterm outcomes including the false lumen (FL) thrombosis rate were monitored in both groups.

RESULTS

The incidence of stroke, delirium and spinal cord ischaemia was 5.9% vs 3.7% (P = 0.533), 5.9% vs 7.4% (P = 0.903) and 5.9% vs 0 (P = 0.533) in the Z2 and Z3 groups, respectively. The 30-day mortality was 9.1% in both groups. The mean distal landing zone was T7.5 (T7; T9) in the Z2 group vs T9 (T8; T10) in the Z3 group (P = 0.668). The 2-year overall survival was 62.2% with no significant difference in the Z2 and Z3 groups (61.6% vs 64.2%; P = 0.940). There were no aortic-related deaths during the follow-up period. Freedom from reintervention at 24 months was 73% and was comparable between Z2 and Z3 (74.1% vs 91.7%; P = 0.123). The rate of early complete FL thrombosis was comparable in the Z2 and Z3 groups. By 24 months of observation in the Z3 group, the rate of complete FL thrombosis was significantly higher (60% vs 77%; P = 0.046).

CONCLUSIONS

No statistically significant differences were observed between landing zones 2 and 3 during the FET procedure with regard to early outcomes. Proximalization of the FET was associated with a shorter FL thrombosis in the midterm follow-up period that affected the distal aortic reintervention rate.

[Predictors of early adverse events after the frozen elephant trunk procedure]

AIM

The aim of this study was to identify predictors of adverse events after the frozen elephant trunk procedure in the early postoperative period.

PATIENTS AND METHODS

Between March 2012 and March 2020, a total of 273 patients were operated on for aortic pathology. A retrospective analysis aimed at identifying probable predictors was performed on 83 patients who underwent the FET procedure. Uni- and multivariate logistic regression was used to identify predictors of such adverse events as postoperative delirium, respiratory failure, acute kidney injury, and in-hospital mortality.

RESULTS

According to the findings of the optimal multivariate regression model, separate reimplantation of the supra-aortic branches was a significant predictor of postoperative delirium (OR 10.41; 95% CI 1.1-35.45; p=0.05); significant risk factors for prolonged respiratory support were the duration of surgery (OR 1.02; 95% CI 1.01-1.03; p<0.001) and postoperative acute renal injury (OR 8.72; 95% CI 1.67-57.38; p=0.014). Independent risk factors for postoperative renal injury turned out to be the true lumen diameter of the descending aorta (OR 1.3; 95% CI 1.1-1.72; p=0.015) and chronic type A aortic dissection (OR 44.07; 95% CI 3.29-2354.8; p=0.014); statistically significant risk factors for in-hospital mortality were multiple organ dysfunction syndrome (OR 14.34; 95% CI 1.69-155.48; p=0.016) and coronary artery stenosis (OR 3.36; 95% CI 1.19-13.26; p=0.042).

CONCLUSION

Separate reimplantation of the supra-aortic branches, duration of surgery, acute kidney injury, chronic aortic dissection, multiple organ dysfunction syndrome, true lumen diameter of the descending aorta, coronary atherosclerosis and haemoglobin level were statistically significant predictors of adverse events in the early postoperative period.

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.