Repair in arterial tissue 2 years after a severe single dilatation injury: the regenerative capacity of the rabbit aortic wall. The importance of endothelium and of the state of subendothelial connective tissue to reconstitution of the intimal barrier

Potential long-term complications of endovascular stent grafting for blunt thoracic aortic injury

Blunt thoracic aortic injury (BTAI) is a rare, but lethal, consequence of rapid deceleration events. Most victims of BTAI die at the scene of the accident. Of those who arrive to the hospital alive, expedient aortic intervention significantly improves survival. Thoracic endovascular aortic repair (TEVAR) has been accepted as the standard of care for BTAI at many centers, primarily due to the convincing evidence of lower mortality and morbidity in comparison to open surgery. However, less attention has been given to potential long-term complications of TEVAR for BTAI. This paper focuses on these complications, which include progressive aortic expansion with aging, inadequate stent graft characteristics, device durability concerns, long-term radiation exposure concerns from follow-up computed tomography scans, and the potential for (Victims of Modern Imaging Technology) VOMIT.

Minimal traumatic aortic injuries: meaning and natural history

OBJECTIVE Minimal aortic injuries (MAIs) are being recognized more frequently due to the increasing use of high-resolution diagnostic techniques. The objective of this case series review was to report the clinical and radiological characteristics and outcomes of a series of patients with MAI. METHODS From January 2000 to December 2011, 54 major blunt trauma patients were admitted to our institution with traumatic aortic injuries. Nine of them presented with MAI, whereas the remaining 45 patients suffered a significant aortic injury (SAI). RESULTS MAIs accounted for 17% of the overall traumatic aortic injuries in our series. Major trauma patients with MAI and SAI were similar regarding the presence of severe associated non-aortic injuries and the expected mortality calculated by injury severity score, revised trauma score and trauma injury severity score. There were no statistically significant differences in in-hospital mortality between MAI (22.2%) and SAI (30.2%). No death in the MAI group was aortic related, whereas five deaths in the SAI group were caused by an aortic complication. The survival of MAI patients was 77.8% at 1 and 5 years. There was no late mortality among MAI patients. The survival of SAI patients was 69.7% at 1 year and 63.6% at 5 and 10 years. None of the seven surviving patients with MAI presented a progression of the aortic injury. In six patients, the intimal tear completely healed in imaging controls, whereas one patient developed a small saccular pseudoaneurysm. CONCLUSIONS Blunt traumas presenting MAI are as severe as traumas that associate SAI and present similar in-hospital mortality. In contrast to SAI traumas, in-hospital mortality due to MAI is not usually related to the aortic injury, so these injuries are more amenable to a conservative management. It is mandatory to perform a close imaging surveillance to detect early any potential adverse evolution of an MAI. Nevertheless, a balance must be struck between a close serial imaging surveillance and the potentially detrimental effects of obtaining high-resolution additional images.

Minimal aortic injury: a lesion associated with advancing diagnostic techniques

BACKGROUND

With the increasing use of high-resolution diagnostic techniques, minimal aortic injuries (MAI) are being recognized more frequently. Recently, we have used nonoperative therapy as definitive treatment for patients with MAI. The current study examines our institutional experience with these patients from July 1994 to June 2000.

METHODS

All patients suspected of blunt aortic injury (BAI) by screening helical CT (HCT) underwent confirmatory aortography with or without intravascular ultrasound (IVUS). MAI was defined as a small (<1 cm) intimal flap with minimal to no periaortic hematoma.

RESULTS

Of the 15,000 patients evaluated by screening HCT, 198 (1.3%) were suspected of having BAI. BAI was confirmed in 87 (44%), and 9 (10%) of these had MAI. The initial aortogram was considered normal in five of the MAI patients. The correct diagnosis was made by IVUS (four patients), and video angiography (one patient). One MAI patient had surgery, and two (22%) died of causes not related to the aortic injury. Follow-up studies were done on the six MAI patients that were discharged. In two, the flap had completely resolved, and in one it remained stable. The remaining three patients formed small pseudoaneurysms.

CONCLUSION

Ten percent of BAI diagnosed with high resolution techniques have MAI. These intimal injuries heal spontaneously and hence may be managed nonoperatively. However, the long-term natural history of these injuries is not known, and hence caution should be exercised in using this form of treatment.

Fogarty and percutaneous transluminal coronary angioplasty balloon injury induce comparable damage to the arterial wall but lead to different healing responses

PURPOSE

Fogarty balloon denudation in experimental animals often serves as a model for percutaneous transluminal coronary angioplasty (PTCA). We compared the healing response of the arterial wall with the use of Fogarty and PTCA balloon dilation.

METHODS

Carotid arteries of rabbits were injured with a 2F Fogarty (n = 9) or a 3 mm PTCA balloon (n = 6). At 1 day endothelial cell removal was qualitatively evaluated in Fogarty balloon lesions and in PTCA balloon lesions with a modified "en face" silver nitrate staining. Medial necrosis was morphometrically determined as percentage medial area. After 21 days endothelial cell coverage was assessed in the center of the lesion with an antibody to CD31 and intimal proliferation with an antibody to the nuclear antigen Ki-67. Intimal hyperplasia area was measured with morphometry. Acute lumen gain directly after Fogarty balloon dilation and PTCA balloon dilation was determined by serial angiography. All data are means +/- SEM.

RESULTS

At 21 days intimal hyperplasia area was higher in the Fogarty balloon lesions than in the PTCA balloon lesions. Intimal hyperplasia area was 0.19 +/- 0.02 mm2 and 0.03 +/- 0.01 mm2, respectively. Immediately after injury the acute gain in luminal diameter did not differ between Fogarty and PTCA balloon dilation (0.37 +/- 0.03 mm and 0.38 +/- 0.05 mm, respectively). At 1 day after injury endothelial cell removal was complete in all segments. Medial necrosis caused by Fogarty (67% +/- 7%) and PTCA balloon dilation (74% +/- 9%) did not differ. At 21 days endothelial cell coverage was almost complete both in the Fogarty balloon lesions and in the PTCA balloon lesions. Intimal proliferation was also higher in the Fogarty balloon lesions than in the PTCA balloon lesions.

CONCLUSION

Despite comparable endothelial cell abrasion and medial necrosis, Fogarty balloon injury elicited significantly augmented intimal hyperplasia compared with PTCA balloon dilation.

Endotoxin, tumor necrosis factor, and dexamethasone effects on human endothelial cell fibronectin dynamics: synthesis, matrix assembly, and receptor expression

The three inflammatory modulators endotoxin, tumor necrosis factor (TNF) alpha, and dexamethasone (DEX) were studied for their effects on fibronectin (FN) dynamics in human umbilical vein endothelial cells. Cell culture supernatants were analyzed for new soluble pool FN synthesis. Endotoxin (LPS) (10 micrograms/mL) decreased the newly synthesized soluble pool of FN (p < 0.05). An increase in soluble FN was demonstrated with 1 and 10 ng/mL TNF alpha (p < 0.05). DEX decreased newly synthesized endothelial cell (EC) FN in the soluble pool at 4, 40, and 400 micrograms/mL (p < 0.05). Extracellular matrix FN content was examined using immunofluorescence. The thick FN mesh seen in control cells contrasted with a decreased FN matrix after treatment with each of the three study agents. Immunoprecipitation of the FN receptor alpha 5 beta 1 integrin from [35S]methionine-labelled cell extracts demonstrated down regulation of receptor expression by both TNF alpha and DEX as compared with control samples. These data indicate that LPS, TNF alpha, and DEX may weaken EC-substratum adhesion by differential effects on FN synthesis and secretion, FN incorporation into the extracellular matrix, and down regulation of FN receptor expression.