Aortic intramural haematoma: remarks and conclusions

Imaging and Biomarkers in Acute Aortic Syndromes: Diagnostic and Prognostic Implications

Acute aortic syndrome (AAS) is an emergency and life-threatening condition including aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer and iatrogenic-traumatic aortic injury. An integrated multiparametric approach (clinical history and examination, electrocardiogram, biomarkers and imaging techniques) is recommended in order to make timely and accurate diagnosis, delineate the prognosis, choose the most appropriate therapeutic interventions tailored for the individual patient. Nowadays the best imaging strategy for diagnosing AAS and its complications is a combination of transthoracic echocardiography and computed tomography angiography (CTA). Transesophageal echocardiography tends to be carried out in complicated cases prior to surgical or endovascular therapy, often in the operating room and under general anesthesia. In this regard, intravascular ultrasound and intraluminal phase array imaging may be implemented during the endovascular procedures depending on operator expertise and cost issues. On the other hand, owing to its intrinsic characteristics, magnetic resonance imaging is an ideal imaging technique for serial measurements in patients at risk of AAS or with chronic dissection. Among biomarkers, D-dimer is the closest to "golden status" (high sensitivity and low negative likelihood ratio). Interestingly, 18fluorodeoxyglucose positron emission tomography/CT is increasingly being used along with specific serologic biomarkers (white blood cells, C-reactive protein, fibrinogen and D-dimer) to detect and monitor vascular inflammation affecting the aorta and systemic arteries. It is expected, in the near future, the development of serologic and imaging biomarkers able to early detect clinically-silent pathologic changes in the aorta wall before (primary prevention) and after (secondary prevention) the acute index event.

Intramural hematoma and penetrating ulcer in the descending aorta: differences and similarities

Acute aortic syndromes include a variety of overlapping clinical and anatomic diseases. Intramural hematoma (IMH), penetrating atherosclerotic ulcer (PAU), and aortic dissection can occur as isolated processes or can be found in association. All these entities are potentially life threatening, so prompt diagnosis and treatment is of paramount importance. IMH and PAU affect patients with atherosclerotic risk factors and are located in the descending aorta in 60-70% of cases. IMH diagnosis can be correctly made in most cases. Aortic ulcer is a morphologic entity which comprises several entities-the differential diagnosis includes PAU, focal intimal disruptions (FID) in the context of IMH evolution and ulcerated atherosclerotic plaque. The pathophysiologic mechanism, evolution and prognosis differ somewhat between these entities. However, most PAU are diagnosed incidentally outside the acute phase. Persistent pain despite medical treatment, hemodynamic instability, maximum aortic diameter (MAD) >55 mm, significant periaortic hemorrhage and FID in acute phase of IMH are predictors of acute-phase mortality. In these cases, TEVAR or open surgery should be considered. In non-complicated IMH or PAU, without significant aortic enlargement, strict control of cardiovascular risk factors and frequent follow-up imaging appears to be a safe management strategy.

Conditional deletion of Rcan1 predisposes to hypertension-mediated intramural hematoma and subsequent aneurysm and aortic rupture

Aortic intramural hematoma (IMH) can evolve toward reabsorption, dissection or aneurysm. Hypertension is the most common predisposing factor in IMH and aneurysm patients, and the hypertensive mediator angiotensin-II induces both in mice. We have previously shown that constitutive deletion of Rcan1 isoforms prevents Angiotensin II-induced aneurysm in mice. Here we generate mice conditionally lacking each isoform or all isoforms in vascular smooth muscle cells, endothelial cells, or ubiquitously, to determine the contribution to aneurysm development of Rcan1 isoforms in vascular cells. Surprisingly, conditional Rcan1 deletion in either vascular cell-type induces a hypercontractile phenotype and aortic medial layer disorganization, predisposing to hypertension-mediated aortic rupture, IMH, and aneurysm. These processes are blocked by ROCK inhibition. We find that Rcan1 associates with GSK-3β, whose inhibition decreases myosin activation. Our results identify potential therapeutic targets for intervention in IMH and aneurysm and call for caution when interpreting phenotypes of constitutively and inducibly deficient mice.

Midterm results of type B intramural hematoma endovascular treatment

BACKGROUND

Recently, intramural hematoma (IMH) has been characterized as a rare variant of aortic dissection, falling within the acute aortic syndromes (AAS). Although aortic endovascular treatment seems to provide good results, no consensus has been established regarding the optimal management of IMH affecting the descending thoracic aorta (IMH B). The aim of this study was to assess long-term clinical and morphological results of IMH B treated with a stent graft.

METHODS

Between 2002 and 2013, 15 of the 423 (3.5%) consecutive patients with AAS were found to have IMH B. During follow-up, complications related to IMH B were observed in 10 patients, including 5 during the acute period (<14 days). Surgical indications were ulcerations, refractory pain, aneurysm evolution, aortic rupture, and pleural effusion. An endovascular approach was taken for all forms with suitable anatomy.

RESULTS

Technical success rate was 100%, with complete exclusion of lesions of the descending thoracic aorta in all cases treated with a stent graft. No neurological complications or deaths occurred within the first 30 postoperative days, nor at the end of the mean follow-up of 46 months (1-137 months). After the aortic stent graft, partial or complete regression of the hematoma was observed in all cases.

CONCLUSIONS

IMH B is most often a progressive disease requiring long-term monitoring. In case of complications, stent-graft treatment of the descending thoracic aorta can be performed successfully in most cases. This procedure appears to be a safe technique that provides very good long-term results, with favorable remodeling of the aorta.

Endovascular stent-graft management of aortic intramural hematomas

PURPOSE

To report initial experience with endovascular stent-grafting in aortic intramural hematoma (IMH).

MATERIALS AND METHODS

From 2000 to 2006, 15 patients (mean age, 67 years; range, 54-83 y) underwent endovascular treatment of aortic IMH. Thirteen patients were admitted for acute aortic syndrome and two for traumatic aortic injury. An endovascular procedure was performed as primary treatment for four patients (type A IMH, n = 3; type B IMH, n = 1) and as a second-line therapy in 11 patients because of unfavorable evolution (type A IMH, n = 1; type B IMH, n = 10). All stent-grafts were placed in the descending aorta, even for type A IMH. The mean follow-up was 21 months (range, 6-72 months).

RESULTS

The primary success rate was 93%, with complete exclusion of the lesion (n = 14). Exclusion was partial for one patient with a type I endoleak (7%). The 30-day mortality rate was zero. IMH evolution was favorable in all cases, with decreased aortic wall thickening (n = 8) or complete regression (n = 7). Complications associated with endovascular repair were mainly related to aneurysm formation (20%). The late death rate was 7%.

CONCLUSIONS

Endovascular stent-graft treatment can be performed in the management of complicated IMH, even in some cases of type A IMH, when an intimal lesion is located in the isthmus or descending aorta with contraindications to surgery. This procedure offers low morbidity and mortality rates, representing a feasible therapeutic option especially for elderly patients with comorbidities. Further studies are necessary to confirm these preliminary results.