Rupture of a thoracic aortic aneurysm: a rare adverse reaction following systemic tissue plasminogen activator infusion

Aortic transgraft hemorrhage after intravenous tissue plasminogen activator therapy in patients with acute ischemic stroke

BACKGROUND

The safety of intravenous recombinant tissue plasminogen activator (IV tPA) therapy for patients with an aortic aneurysm or undergoing aortic graft replacement has not been established. We evaluated the incidence, bleeding site, coagulation factors, and clinical outcomes of patients treated with IV tPA for acute stroke.

METHODS

Between October 2005 and May 2013, 394 ischemic stroke patients were treated in our stroke center with IV tPA. Among these patients, we investigated those who had a history of aortic aneurysm with or without aortic graft replacement before IV tPA therapy and underwent computed tomography imaging. We compared the levels of D-dimer and hemoglobin (Hb) around IV tPA therapy between the patients with and without tPA-associated periaortic bleeding.

RESULTS

Seven patients with a history of aortic aneurysm (3 men; mean age: 80.4 years) were examined; 3 had undergone aortic graft replacement, and 2 had experienced tPA-associated bleeding around vascular grafts. The serum D-dimer levels in those with bleeding were only slightly higher before tPA than in those without (median: 10.5 vs. 1.5 μg/mL) but were elevated 1 day after tPA (107.4 vs. 8.6 μg/mL). The Hb levels 2 days after tPA were comparable with those before tPA (11.9 vs. 11.8 g/dL) but were lower in the patients with bleeding than in those without (8.5 vs. 11.7 g/dL). Surgical intervention was not required, although 1 patient required blood transfusion.

CONCLUSIONS

Our analysis provides reassurance regarding the risk of IV tPA therapy in patients undergoing aortic graft replacement.

Ascending aorta dilatation in aortic valve disease: morphological analysis of medial changes

We investigated whether and how the severity of medial degeneration lesions varies along the circumference of the dilated intrapericardial aorta. Two groups of aortic wall specimens, respectively harvested in the convexity and concavity of ascending aorta in 72 patients undergoing surgery for dilatation of the intrapericardial aorta associated with aortic valve disease, were separately sent for pathology, morphometry, and ultrastructural examination. Cystic medial necrosis, fibrosis, and elastic fiber fragmentation were classified into three degrees of severity; their mean degree and morphometric findings in the convexity and in the concavity specimens were compared by paired t-test. Correlation between echocardiographic degree of aortic dilatation and severity of medial degeneration was assessed separately for each of the two groups of specimens. Morphologically, medial degeneration was found in all cases; a higher mean degree was found in the convexity group (2.39 +/- 0.58 vs 1.44 +/- 0.65 in the concavity group; P < 0.001). At morphometry normal smooth muscle cells in the convexity specimens were significantly reduced (P = 0.007); the length (P = 0.012) and number (P = 0.009) of elastic fibers reduced and increased, respectively. Moreover, in the convexity specimens a significantly smaller amount of smooth muscle cells and an increase of immunohistochemical labeling of apoptosis-associated proteins in the subintimal layer of the media was noticed. Correlation between aortic ratio and medial degeneration degree was significant in the convexity group (P < 0.001), but not in the concavity group (P = 0.249). Scanning electron microscopy analysis confirmed morphological results and allowed us to better distinguish the early pathological cavities from the microvessels, which were in the outer media in normal aorta and ubiquitous in aortitis or atherosclerosis. Electron transmission microscopy analysis showed changes in the extracellular matrix and smooth muscle cells, and these changes increased from the intima to the adventitial layer of the media. In dilated intrapericardial aorta, medial degeneration changes and expression of apoptosis-associated proteins are more marked in the ascending aorta convexity, likely due to hemodynamic stress asymmetry. Ultrastructural findings allow us to distinguish the early medial changes not yet evident on light microscopy.