Traumatic rupture and aneurysm of the aortic isthmus: late results of repair by direct suture

A three-layer model for buckling of a human aortic segment under specific flow-pressure conditions

Human aortas are subjected to large mechanical stresses because of blood flow pressurization and through contact with the surrounding tissue. It is essential that the aorta does not lose stability by buckling with deformation of the cross-section (shell-like buckling) (i) for its proper functioning to ensure blood flow and (ii) to avoid high stresses in the aortic wall. A numerical bifurcation analysis employs a refined reduced-order model to investigate the stability of a straight aorta segment conveying blood flow. The structural model assumes a nonlinear cylindrical orthotropic laminated composite shell composed of three layers representing the tunica intima, media and adventitia. Residual stresses because of pressurization are evaluated and included in the model. The fluid is formulated using a hybrid model that contains the unsteady effects obtained from linear potential flow theory and the steady viscous effects obtained from the time-averaged Navier-Stokes equations. The aortic segment loses stability by divergence with deformation of the cross-section at a critical flow velocity for a given static pressure, exhibiting a strong subcritical behaviour with partial or total collapse of the inner wall. Preliminary results suggest directions for further study in relation to the appearance and growth of dissection in the aorta.

Sudden-onset paraplegia due to thrombosis of false aneurysm: late complication after prosthetic replacement of the descending thoracic aorta

Traumatic rupture involving the isthmus of the descending thoracic aorta is a rarely treated injury in vehicular accident victims. A possible long-term complication of prosthetic replacement of the damaged aortic segment is false aneurysm. This report describes a case of sudden-onset acute paraplegia resulting from thrombosis of a false aneurysm associated with a prosthesis placed 10 years earlier for repair of traumatic rupture of the aortic isthmus.

[Acute traumatic rupture of the thoracic aorta and its branches. Results of surgical management]

STUDY AIM

The aim of this retrospective study was to report a series of 102 patients with acute traumatic rupture of the thoracic aorta and its branches (TRA) and to evaluate long-term results.

PATIENTS AND METHODS

From April 1977 to April 2000, 102 patients with RTA were admitted to our unit. Age ranged between 12 and 74 years (mean age: 33 years). Localisation was: ascending aorta (n = 3), aortic arch (n = 1), isthmus (n = 92), descending aorta (n = 1), innominate artery (n = 3), and left subclavian artery (n = 2). Associated injuries mainly included craniocerebral lesions (n = 76), rib fractures (n = 68), and thoracic (n = 38), and abdominal (n = 24) lesions. Average time between trauma and surgery was 37 hours. Aortography was used routinely for diagnosis. Five patients were inoperable; the procedure was delayed in three patients. In all but two patients with rupture of the isthmus, descending aorta and subclavian artery, the operation included venous arterial femorofemoral assistance. Rupture was partial in 37 patients (37 direct sutures), and complete in 55 patients (40 direct sutures). In two cases of left subclavian artery desinsertion, the operation included suture of the aortic tear and reimplantation of the artery. In patients with rupture of the ascending aorta and aortic arch, surgery was carried out under cardiopulmonary bypass with deep hypothermia for aortic arch rupture. Repair consisted of direct suture. In patients with rupture of the innominate artery, the lesion was treated under cardiopulmonary bypass by direct suture. In five cases, abdominal injuries required emergency procedure before aortic repair.

RESULTS

Four patients died. No postoperative paraplegia occurred. The high morbidity rate was in relation to the associated injuries. Among the 93 survivors, the aortic clinical status was satisfactory in 91 patients (two patients were lost to follow-up). Two patients died from cancer and myocardial infarction 2 and 7 years later respectively. One patient had prosthetic sepsis and was reoperated on with homograft. Angiographic control by aortography (n = 60) and angioMRI (n = 22) was normal in 76 patients. There were five stenoses at the level of the prosthesis, four with a gradient < 20 mmHg and one with a gradient > 50 mmHg and one aneurysm at the level of the isthmus. These last two patients were reoperated on with good result.

CONCLUSION

RTA remains a surgical emergency with multiple difficulties. Despite the development of new imaging modalities, angiography remains the gold standard for the work-up of these patients. Venous arterial femorofemoral assistance with a pump remains the best procedure in order to avoid paraplegia and vascular prosthesis implantation when possible. Endovascular stent graft insertion, although still under investigation, holds tremendous promise for non-surgical treatment of these patients.

Traumatic rupture of the aortic isthmus: an emergency?

The objectives of this study were to explore the hypotheses that: (1) patients with traumatic rupture of the aortic isthmus (TRA) who have not exsanguinated into the pleural cavity upon hospital presentation are unlikely to develop rupture of the hematoma during the time necessary to investigate all injuries and attend to those of more immediate danger; and (2) appropriate medical therapy can prevent free rupture of the hematoma. The medical records of 112 patients who were proved to have TRA at the isthmus resulting from injury within the preceding 7 days were reviewed. Fifty of these patients received medical treatment aimed at decreasing aortic wall stress; 46 were managed under a formal protocol. The available English language and European literature for the past 15 years was surveyed for evidence of the effects of delay between injury and aortic repair. Eight patients died before aortic repair, six of aortic exsanguination (all within 4 hours of injury). Of 77 patients for whom the time of injury was recorded and the aorta was repaired, 36 were repaired within 12 hours of injury and 41 between 12 hours and 24 weeks; none developed aortic hemorrhage. No patient receiving adequate medical therapy died of rupture of the hematoma. Other major surgery preceded aortic repair in 33 patients. We conclude that the concept that traumatic rupture of the aorta should always take priority over other injuries is incorrect. Pharmacologic reduction of wall stress appears to decrease the probability of rupture of the periaortic hematoma.

Echocardiographic diagnosis of secondary coarctation complicating the repair of a traumatic pseudoaneurysm of the aorta

An 18-year-old patient underwent repair of traumatic aortic pseudoaneurysm. Postoperatively, the physical examination showed hypertension with 30 mm Hg gradient between the upper and lower extremities. Doppler echocardiographic evaluation demonstrated a new (secondary) aortic coarctation at the site of the repair. Transesophageal echocardiography revealed the detailed anatomy and the cross-sectional area of the coarctation.