Serial Images Demonstrating Proximal Extension of an Aortic Intramural Hematoma
A 73-year-old woman with history of hypertension presented to our institution with short-term onset of severe back pain. On physical examination, her pulse was 110 bpm and blood pressure was 134/77 mm Hg, equal in both arms. Examination of the heart revealed a 1/6 diastolic murmur heard at the base. ECG showed sinus tachycardia with no evidence of ischemia. A computed tomography scan was performed to rule out aortic dissection. A type B intramural hematoma (IMH) was found, originating just distal to the left subclavian artery and extending to the superior mesenteric artery (Figure 1A). Four hours after the computed tomography scan, the patient developed additional symptoms of chest and stomach pain. A transesophageal echocardiogram was done to rule out further extension. No evidence of involvement proximal to the descending aorta (Figure 1B) was seen. In addition, mild aortic regurgitation was noted. A cardiac surgeon was consulted, and the decision was made to treat the patient medically.
The patient was stable until the fourth hospital day, when she developed recurrent severe back pain and throat pain. Repeat computed tomography scans performed with and without contrast showed proximal extension of the IMH into the ascending aorta (Figure 2). The patient underwent emergent cardiac surgery. An intraoperative epicardial echocardiogram of the ascending aorta confirmed the proximal location of the IMH (Figure 3). On gross inspection, the ascending aorta had bluish discoloration consistent with a hematoma. The ascending aorta was resected (Figure 4) and replaced by an intervascular graft. The aortic valve was structurally intact and was therefore not replaced. After surgery, the patient did well and was discharged on the third postoperative day.
IMH is a variant form of aortic dissection characterized by a rupture of the vasa vasorum. IMH accounts for 13% to 27% of all aortic dissections, but it differs from typical aortic dissection in that there is no intimal tear or communication between the hematoma and the aortic lumen. Presentation, management, and classification are similar to those of typical dissection. Although type B IMH is usually treated medically, it may occasionally progress to type A dissection and require surgical intervention, as was the case with this patient.