Objectives:
The interdigitating technique in aortic arch reconstruction in hypoplastic left heart syndrome and variants (HLHS) is very effective to minimize the recoarctation rate. Little is known on the aortic arch’s growth characteristics and the resulting clinical impact.
Methods:
139 patients with HLHS underwent staged palliation between 2007 and 2014. 72 patients who underwent Norwood arch reconstruction with the interdigitating technique were included. Dimensions of the ascending aorta (AA), transverse arch (TA), isthmus (IA) and descending aorta (DA) in pre-stage II (P1, n=50) and pre-Fontan (P2, n=21) angiograms were measured and geometry and growth characteristics of the aortic arches were analyzed. Correlations between the aortic dimensions and clinical outcomes were assessed.
Results:
There were significant increases in diameters in all segments between P1 and P2 (p < .0005). The z-scores in AA, TA and IA were unchanged between P1 and P2 (p = .931/.425/.121), but increased significantly in DA at P2 (p = .039). The percent increase in diameters were comparable among 4 segments (mean, 146% in IA, 144 in DA, p=.648). There were correlations in dimensions and z-scores between P1 and P2 in AA (p = .029/.013) and TA (p = .001/ < .0005), but no correlations were found in IA (p = .140/.747) and DA (p = .075/.432). The most significant tapering in the arch dimension occurred between TA and IA in both time points (P1, 67.3% vs. P2, 61.1%, p=.303). The reverse coarctation index (TA/IA ratio) at P1 (r = .381, p = .042), but not coarctation index (CoAI, IA/DA ratio) at P1 (p = .774) had a significant correlation with post-stage II ventricular function. Balloon dilatation for recoarctation was needed in 2 (2.7%) patients prior to stage II palliation. CoAI at P1 was a predictor for ventricular dysfunction at latest follow-up (p=.017).
Conclusions:
Aortic arch growth after interdigitating reconstruction in HLHS is substantial and relatively constant. The isthmus growth is proportional to other segments. Overall reintervention rate for recoarctation is exceptionally low. CoAI prior to stage II palliation may be associated with long-term ventricular function.
Potential Molecular Mechanism of Retrograde Aortic Arch Stenosis in the Hybrid Approach to Hypoplastic Left Heart Syndrome
