Objective: Type B aortic dissection (TBAD) is commonly thought of as a sporadic event. However, an increasing body of data has suggested that genetic factors can influence TBAD. Our aim was to determine the prevalence of heritable TBAD, defined as either syndromic TBAD or nonsyndromic familial TBAD and to detail the natural history and long-term clinical outcomes compared with patients with "sporadic" TBAD without an identified syndrome or family history.
Methods: The clinical records of 389 patients with TBAD who had presented to a single health care system from 1995 to 2017 were reviewed. A family history was obtained by interview and/or medical record review. Syndromic TBAD was defined as TBAD in patients with Marfan, Loeys-Dietz, or vascular Ehlers-Danlos syndrome. Nonsyndromic familial TBAD was defined as a family history of aortic or arterial aneurysm or dissection and/or sudden death in a first- or second-degree relative in the absence of a known syndrome. Patients with syndromic and nonsyndromic familial TBAD were compared with patients with sporadic TBAD in terms of the comorbid conditions, aortic repair, and mortality.
Results: Of 389 patients (71.2% male) with TBAD, the etiology of TBAD was heritable in 27.9% (9.6% syndromic; 18.3% nonsyndromic familial TBAD) and 72.1% sporadic of the cases. Patients with syndromic and nonsyndromic familial TBAD had been more frequently referred in the chronic phase than were the patients with sporadic TBAD (35.5% vs 44.1% vs 25.8%; P = .014) and had presented at a younger age (40.6 ± 10.9 years vs 55.2 ± 11.3 years vs 62 ± 12.9 years; P < .001) and with lower blood pressure at acute TBAD (systolic, 159.2 ± 21 mm Hg vs 178.9 ± 39.3 mm Hg vs 186.1 ± 38.4, P = .01; diastolic, 84.3 ± 17.3 mm Hg vs 91.4 ± 24.1 mm Hg vs 101.6 ± 22.3 mm Hg, P = .001). Among patients with acute TBAD surviving to discharge from the initial hospitalization, thoracic endovascular aortic repair (TEVAR) had been performed in 115 patients, with no significant differences in TEVAR usage in the three groups. However, those with syndromic and nonsyndromic familial TBAD had had a greater incidence of retrograde aortic dissection after TEVAR (33.3% vs 15% vs 3%; P = .006). They had also required a greater number of arch repairs (30% vs 10.5% vs 3.6%; P < .001) and had died at a younger age (47.7 ± 13.1 years vs 65.7 ± 13.7 years vs 72.8 ± 12.7 years; P < .001). Aortic-related mortality was more common among patients with syndromic TBAD (36.7% vs 12.3% vs 17.6%; P = .016).
Conclusions: In our single-institutional experience, heritable TBAD accounted for one in four patients with TBAD. Nonsyndromic familial TBAD was twice as common as syndromic TBAD and appeared to share many clinical features. Identifying these patients early in their disease course and personalizing their care might improve their survival.
Keywords: Familial aortopathy; Genetically triggered thoracic aortic disease; Heritable thoracic aortic disease; Thoracic aortic aneurysms and dissections; Type B aortic dissection.
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