Long-term survival and related outcomes for hybrid versus traditional arch repair-a meta-analysis

Abstract

Background: Surgical interventions for aortic aneurysm and dissection remain associated with high risk of mortality and morbidity. Advances in operative techniques have led to a variety of options for the cardiac surgeon, including endovascular and hybrid approaches. Debate remains over which of these techniques provide optimal outcomes for the patient. The present systematic review and meta-analysis aims to evaluate long term patient survival and identify short-term outcomes for conventional (open) aortic arch repair and hybrid aortic arch repair (HAR).

Methods: An electronic literature search was conducted according to predefined inclusion criteria for hybrid and conventional aortic arch repair surgery. Digitized survival data was extracted from identified studies' Kaplan-Meier curves and used to re-create individual patient data for aggregated survival analysis. Post-operative morbidity and mortality were analyzed using random-effects model meta-analysis.

Results: Nine studies were included, containing 841 hybrid arch repair and 1,182 conventional arch repair patients. Pooled Kaplan-Meier analysis of all patients demonstrated higher survival in hybrid arch repair patients than conventional arch repair patients, however, this was noted to be sensitive to results from a particular study. Overall results showed for the hybrid repair cohort, survival at 1, 2, 3, 5 and 7 years was 87%, 85%, 83%, 78% and 75%, respectively. Survival in the conventional repair cohort at 1, 2, 3, 5 and 7 years was 84%, 82%, 80%, 75% and 71%, respectively. Statistically significant findings from meta-analysis showed hybrid arch repair was associated with lower risk of re-operation for bleeding, while conventional arch repair was associated with reduced risk of spinal cord injury.

Conclusions: Pooled Kaplan-Meier analysis of all studies showed long-term survival outcomes for hybrid and conventional aortic arch repair patients are heterogeneous and sensitive to the results of particular studies. Superior results from particular centres and the low number of comparative studies mean that more data is required to make definitive findings with regards to the long-term survival outcomes of either procedure. Hybrid arch repair was associated with lower risk of re-operation for bleeding, while conventional arch repair was associated with lower risk of spinal cord injury. Surgeons should consider their own center's experience and patient suitability when deciding between hybrid or conventional aortic repair techniques.

Keywords: Open surgical repair; aortic arch aneurysm; aortic arch replacement; elephant trunk; hybrid arch repair (HAR).

Figure 1

Kaplan-Meier survival of entire pooled cohort. Patient time-to-event data was individually calculated for each study and all patients then combined into an aggregated cohort.

Figure 2

Forest plot for relative risk of spinal cord injury following HAR and CTAR. HAR, hybrid aortic arch repair; CTAR, conventional total aortic arch repair.

Figure 3

Forest plot for relative risk of re-operation for bleeding following HAR and CTAR. HAR, hybrid aortic arch repair; CTAR, conventional total aortic arch repair.

Figure S1

PRIMSA flow chart detailing the literature search process for hybrid versus traditional aortic arch repair.

Figure S2

Kaplan-Meier survival of pooled cohort excluding patients from Sun 2011. Patients in Sun 2011 were significantly younger than patients from other included studies and a large proportion of the conventional repair cohort were hemi-arch repair only: removal of Sun increased the mean age of the cohort and its subsets by 5 years and significantly narrowed the CIs [all patients: 66.4 (63.7; 69.1) years, hybrid patients: 68.8 (64.3; 73.2) years, CTAR patients: 63.1 (60.0; 66.2) years]. CTAR, conventional total aortic arch repair.

Figure S3

Early mortality endpoint RR for included studies. RR, relative risk.

Figure S4

Neurological endpoint relative risk between HAR and CTAR for all studies reporting those outcomes. HAR, hybrid aortic arch repair; CTAR, conventional total aortic arch repair.

Figure S5

AKI and haemodialysis endpoint relative risk between HAR and CTAR for all studies reporting those outcomes. AKI, acute kidney injury; HAR, hybrid aortic arch repair; CTAR, conventional total aortic arch repair.

Figure S6

Prolonged ventilation outcome (>48 hours ventilation requirement) relative risk between HAR and CTAR. Note that with exclusion of Yoshitake, relative risk remained insignificant (I² was reduced to 0%). HAR, hybrid aortic arch repair; CTAR, conventional total aortic arch repair.

Figure S7

Bubble plot and corresponding results from meta-regression of early mortality outcome using covariate as median year of study recruitment. Although the regression accounts for variance in the data (high R²), the null hypothesis (β₁=0) for the regression coefficient of cannot be rejected.

Figure S8

Funnel plot for assessing bias in outcomes for early death. Egger’s test result indicates the null hypothesis of symmetry holds true given P>0.05, i.e., bias is unlikely to be present. Note that the test has been applied for less than 10 studies.

Figure S9

Relative risk for early mortality re-evaluated excluding results by Tokuda 2016.