Intimal tear without hematoma - An important variant of aortic dissection that can elude current imaging techniques

Background-The modern imaging techniques of transesophageal echocardiograph y, CT, and MRI are reported to have up to 100% sensitivity in detecting the classic class of aortic dissection; however, anecdotal reports of patient deaths from a missed diagnosis of subtle classes of variants are increasing ly being noted. Methods and Results-In a series of 181 consecutive patients who had ascendi ng of aortic arch repairs, 9 patients (5%) had subtle aortic dissection not diagnosed preoperatively. All preoperative studies in patients with missed aortic dissection were reviewed in detail. All 9 patients (2 with Marfan s yndrome, 1 with Takayasu's disease) with undiagnosed aortic dissection had undergone greater than or equal to 3 imaging techniques, with the finding o f ascending aortic dilatation (4.7 to 9 cm) in all 9 and significant aortic valve regurgitation in 7. In 6 patients, an eccentric ascending aortic bul ge was present but not diagnostic of aortic dissection on aortography. At o peration, aortic dissection tears were limited in extent and involved the i ntima without extensive undermining of the intima or an intimal "flap." Eig ht had composite valve grafts inserted, and all survived. Of the larger ser ies of 181 patients, 98% (179 of 181) were 30-day survivors. Conclusions-In patients with suspected aortic dissection not proven by mode rn noninvasive imaging techniques, further study should be performed, inclu ding multiple views of the ascending aorta by aortography. If patients have an ascending aneurysm, particularly if eccentric on aortography and associ ated with aortic valve regurgitation, an urgent surgical repair should be c onsidered, with excellent results expected.