['Arterial tortuosity is described as a common and distinctive feature of Loeys-Dietz syndrome (LDS), yet reports on arterial tortuosity are based on qualitative observations and none have investigated an association between tortuosity and cardiovascular outcomes in LDS or other connective tissue disorders.', "We performed a retrospective analysis of 90 patients ≤50 years of age with Marfan syndrome, LDS, Ehlers-Danlos syndrome, or nonspecific connective tissue disorder who underwent thoracic contrast-enhanced magnetic resonance angiography. Controls (n=30) underwent magnetic resonance imaging to exclude arrhythmogenic right ventricular dysplasia. Using a volume-rendered angiogram, vertebral arteries were measured along the curvature of the vessel (actual length) and linearly (straight length), and distance factor was calculated: [(actual/straight length-1)×100]. Each subject's maximum distance factor was designated the Vertebral Tortuosity Index (VTI). The VTI was compared among diagnostic groups and among patients with cardiac surgery, dissection, and death. Median age at magnetic resonance imaging was 19.6 years (range 0.2 to 50.1). VTI interrater reliability was excellent (intraclass correlation coefficient =0.987). The VTI was higher in Marfan syndrome (n=57, median 26; interquartile range 10 to 49) and LDS (n=13, median 58; interquartile range 18 to 92) compared with controls (median 4.5; interquartile range 3 to 6; P<0.001 for both). Higher VTI was associated with younger age at surgery even when controlling for root size (adjusted P=0.002). Vertebral tortuosity index ≥50 was associated with earlier age at dissection and death compared with VTI <50 (P=0.001 versus P<0.001). We found no difference in age at surgery, dissection, or death in Marfan syndrome compared with LDS."] Is increased vertebral artery tortuosity index associated with adverse outcomes in children and young adults with connective tissue disorders?