Objective: To investigate the clinical outcomes influenced by distal extension of false lumen in acute type B aortic dissection (TBAD) patients following thoracic endovascular aortic repair (TEVAR)., Methods: From April 2002 to January 2013, 264 TBAD patients treated with TEVAR were retrospectively enrolled. The IIIa group exhibited a distal false lumen above the diaphragm (n = 70), and the IIIb group exhibited a distal false lumen under the diaphragm (n = 194). The morphological characteristics and adverse events (30-day and >30 days) were recorded and evaluated., Results: There were no significant differences between the two groups regarding the demographics, comorbidity profiles, or initial feature of computed tomography angiography. The incidence of true lumen compression and branch involvement were significantly increased in the IIIb group compared with the IIIa group (8.6% vs. 25.3%, respectively; 15.7% vs. 36.1%, respectively, both P < 0.05). The 30-day mortality rate was 1.0% (2/194) in the IIIb group, whereas the IIIa group was zero. The incidence of early adverse events, the 5-year cumulative freedom from adverse events, and the 5-year cumulative freedom from all-cause mortality rate were not significantly different between the IIIa and IIIb groups (2.9% vs. 6.7%, 81.4%, and 80.4%, and 95.7% vs. 93.8%, respectively, all P > 0.05). Log-rank tests also indicated there was no significant difference., Conclusions: There was no significant difference between the IIIa and IIIb groups in the 5-year morality and adverse aortic events following TEVAR. The distal extension of false lumen prior to TEVAR does not influence the long-term morality and adverse aortic events in acute TBAD., (© 2016 Wiley Periodicals, Inc.)