The Value of the Modified Arch Landing Areas Nomenclature (MALAN) as a Predictor of Outcome After TEVAR

Abstract

Introduction - The proximal landing zone for thoracic endovascular aortic repair (TEVAR) can be described using the Modified Arch Landing Areas Nomenclature (MALAN), in which each landing area is identified indicating both Ishimaru’s zone and Type of arch 1 (e.g. 0/I). Previous studies have shown that the MALAN classification is associated with a consistent pattern of angulation2, tortuosity2, and hemodynamic parameters3, which identify hostile proximal landing zones potentially at high risk for early and late complications after TEVAR. The aim of this study was to investigate the outcome prediction value of the MALAN classification. Methods - A multicenter retrospective analysis was performed. All consecutive patients who were treated by TEVAR between 2007 and 2017 and had a proximal landing zone 2 or 3 were included. Preoperative imaging data was used to determine the type of arch for each patient. Landing areas 2/III and 3/III were considered hostile, whereas 2-3/I and 2-3/II were considered favorable. Primary clinical success, primary assisted clinical success, secondary clinical success, as defined by reporting standards on TEVAR, and all-cause mortality were assessed and compared for hostile versus favorable MALAN landing zones. Results - 208 patients were included, 106 patients with a hostile and 102 with a favorable MALAN landing zone. Patients with a hostile MALAN zone were older (70±10 vs. 60±18 years; p<0.01), more frequently had chronic renal failure (20.2% vs. 9.9%; p=0.04), were less often treated urgently or emergently (33.0% vs. 52.5%; p<0.01), had a larger maximum aortic diameter (59±15 vs. 49±21 mm; p<0.01), There were no preoperative differences in terms of gender, diabetes, smoking, COPD, coronary artery disease, stroke, anticoagulation therapy, prior arch surgery, or ASA classification. Proximal stent graft diameter was larger in patients with hostile MALAN zone (37.0 vs. 32.9 mm; p<0.01). There were no differences in terms of stent graft type used, frequency of debranching procedures, or other intraoperative adjunctive procedures. No differences were observed in the technical success rates (93.3% vs. 97.0%; p=0.33) and in the rate of early endoleaks (Type Ia: 6.6% vs. 3.9%; Type Ib: 0.9% vs. 2.0%; Type II: 8.5% vs. 6.9%; Type III: 1.9% vs. 0%; p=0.50). At 30 days, however, MALAN hostile zones had a lower primary clinical success rate (83.0% vs. 91.2%; p=0.08), a lower primary assisted clinical success (84.9% vs. 93.1%; p=0.06), a lower secondary clinical success (89.6% vs 93.1%; p=0.37), and an increased mortality (8.5% vs 3.9%; p=0.17). Mean follow-up duration was 28.9±27.7 months. At 5 years follow up, the estimated primary clinical success was also lower in MALAN hostile group (54.6±6.9% vs. 68.6±6.4%; p=0.04), as was the primary assisted clinical success (58.6±7.0% vs. 74.0±7.3%; p=0.02), and secondary clinical success (73.8±6.0% vs. 83.0±6.4%; p=0.08), while the all-cause mortality was higher (32.9±6.6% vs. 13.1±3.4%; p=0.05). Conclusion - A hostile MALAN zone is associated with worse clinical outcomes after TEVAR. The use of MALAN classification may improve the preoperative decision making process.