Endovascular solutions for diseases of the thoracic aorta

Technology is proceeding at a very brisk pace. Harnessing that technology for clinical use is both a challenge and an opportunity. This combination of surgical and interventional methods has allowed for improved clinical outcomes in certain complex aortic problems. This article explores and discusses new techniques used in detection and treatment of diseases of the thoracic aorta.     

Endovascular treatment of the malignant thrombus in the descending thoracic aorta

Thrombus in the Non-aneurysmal, Non-atherosclerotic Descending Thoracic Aorta (NAADTA) represents a rare source of peripheral arterial embolism. Despite being mostly asymptomatic process, its consequences can be very serious. In this case report, we described the case of a patient with malignant thrombus occurring in otherwise “healthy” descending thoracic aorta, already complicated by embolization into superior mesenteric artery, subsequently solved by stent graft implantation into the thoracic aorta.     

The history of surgery of the thoracic aorta

Until the late 19th century, treatment of thoracic aortic aneurysms relied on ligation of the parent vessel or introduction of foreign materials to promote coagulation or fibrosis. A major breakthrough occurred in 1888, when Rudolph Matas reported an internal repair technique known as endoaneurysmorrhaphy. In this approach, the clot was excised from the aneurysmal sac, and the orifices of the arteries that entered the sac were sutured from within, reestablishing continuous blood flow. At the beginning of the 20th century, Alexis Carrel and Charles Guthrie began to lay the foundation for modern vascular anastomotic techniques. Although isolated successes were reported, optimal treatment of thoracic aortic disease awaited the development of reliable synthetic grafts in the 1950s and 1960s. During the past 15 years, the treatment goal has reverted to endoaneurysmorrhaphy, involving the use of a suitable graft to restore aortic continuity.     

Recent developments in surgery of the thoracic aorta

Aortic surgery is under continuous development. This applies to the aortic root where more and more reconstructive efforts are being made but also to intraoperative means of organ protection. Likewise, the endoluminar stent graft approach to downstream pathologies of the aorta has broadened the classical treatment option "replacement" by "exclusion". Some of these evolving changes in operative strategies and indications are discussed on the basis of a single-center experience.     

Endovascular repair of lesions of descending thoracic aorta: aneurysms and dissections

The morbidity and mortality of open repair of descending thoracic aortic lesions remains uncomfortably high. Shortly after the advent of an endovascular approach for infrarenal abdominal aortic aneurysms, attempts have been made to apply similar technologies to the thoracic aorta. Early experiences with endovascular grafts for thoracic aortic aneurysms have met with good to moderate success but have provided a framework for development of improved technologies specifically designed for this anatomic region. Early studies with second generation devices have shown more promise. Aortic dissections, a disease state associated with an exceptionally high morbidity and mortality, represent another condition that is readily treated with an endovascular approach.     

Endovascular stent-graft placement for acute and contained rupture of the descending thoracic aorta.

OBJECTIVES: To identify determinants of postinterventional death after endovascular stent-graft placement for acute rupture of the descending thoracic aorta, an emerging therapeutic modality for this highly life-threatening condition. METHODS: Between July 1999 and November 2004, 17 patients (14 males; mean age, 65+/-16 (25-83) years) underwent stent-graft repair of the descending thoracic aorta for acute rupture from a thoracic aneurysm (TAA, n=6), acute aortic dissection (AAD, n=6), penetrating aortic ulcer (PAU, n=3), or blunt chest trauma (n=2). Immediate, 30-day, 1-year, and 3-year mortality was assessed. Twenty-one clinical and procedural variables were evaluated in a post-hoc analysis regarding their influence on mortality. Of these, four preprocedural factors with the greatest impact were used to construct a rupture score with a scale from 0 (no adverse prognostic factors present) to 4 (all four adverse factors present). RESULTS: Stent-graft placement was technically feasible in all patients. Complete exclusion of the ruptured aortic pathology could be achieved in only 11 (65%) patients, despite implantation of 1.6+/-0.9 stent-grafts per patient, with a median length of 130 mm. There was one procedure-related early complication (bleeding at the access site). One patient died immediately following the procedure because of progressive mediastinal hematoma, although the rupture site was effectively sealed. Overall survival rates were (76.5+/-10.3)% at 30 days and (52.9+/-12.1)% at 1 year and remained at (52.9+/-12.1)% at 3 years. The four most important preprocedural denominators of death were (1) TAA or AAD as the underlying etiology of aortic rupture (P=0.024), (2) maximum aortic diameter>5 cm (P=0.024), (3) presence of mediastinal hematoma (P=0.056), and (4) an estimated lesion length requiring >1 stent-graft to be covered (P=0.009). Furthermore, residual leakage at the conclusion of the procedure (P=0.009), postprocedural need for dialysis (P=0.004), and prolonged ventilation (P=0.043) were significantly associated with postprocedural death. Using a threshold of >or=3, the rupture score constructed on the basis of the four preprocedural denominators of death was found to be well suited to discriminate postprocedural death (1-year survival: (20.0+/-12.7)% in patients with a rupture score>or=3 vs. 100% in patients with a rupture score<3, P=0.001). CONCLUSION: Endovascular stent-graft placement in patients with acute aortic rupture was technically feasible, albeit still associated with high mortality. A simple risk score constructed in retrospect, on the basis of preprocedural prognostic factors, appeared to provide a useful separation of candidates who are likely to benefit from a straightforward endovascular procedure and should be tested prospectively in future studies.     

The Value of transoesophageal echocardiography for diagnosis of thoracic aorta pathology

The potential of transoesophageal echocardiography for preoperativediagnosis of thoracic aorta pathology was evaluation in 15 patientswith aortic aneurysm. The transoesophageal echocardiographicfindings were compared with 14 computed tomograms and 21 angiograms.Six patients underwent only transoesophageal echocardiography.All patients were operated upon and the surgical findings wereused as a reference for these diagnostic methods. Transoesophagealechocardiography establised a complete and correct diagnosisin 27 patients. The diagnosis was partically correct in threepatients, all having an aortic dissection. A complete and correctdiagnosis was obtained by computed tomography and angiographyin 8 and 17 patients, respectively. The results indicated thattransoesophageal echocardiography is a sensitive and convenientmethod for the definitive diagnosis of pathology of the thoracicaorta. It could become the technique of choice in patients suspectedof having acute aorta pathology as it enables a rapid and definitivediagnosis at the bedside.     

The role of intraoperative two-dimensional echocardiography in the assessment of thoracic aorta pathology

The role of intraoperative two-dimensional echocardiography is discussed in 15 consecutive patients with thoracic aorta pathology undergoing cardiac surgery. A 5 MHz mechanical scanner was used before and immediately after cardiopulmonary bypass. In 5 patients intraoperative two-dimensional studies revealed crucial morphologic information which, consequently, had a marked influence on their planned surgical procedure. In 3 patients the findings provided additional information whereas in the remaining patients the intraoperative echocardiographic findings confirmed the preoperative diagnosis. Following surgery the adequacy of cardiac repair was assessed and, in one patient, epicardial echocardiography indicated the necessity for reoperation. The application of intraoperative two-dimensional echocardiography leads to a better understanding of the pathology involved and facilitates a more appropriate decision concerning the surgical procedure.     

Bilateral axillary arterial perfusion in surgery on thoracic aorta

Bilateral axillary arterial cannulation for selective cerebral perfusion might minimize cerebral embolic complications during surgery on the ascending aorta and aortic arch. From March 2002 through February 2004, bilateral axillary arterial perfusion was applied in 12 consecutive patients (mean age, 61.3 years). Operative procedures were total arch replacement in 8 patients, hemiarch replacement in 1, and ascending aorta replacement in 3. Antegrade selective cerebral perfusion was established through vascular grafts anastomosed to the bilateral axillary arteries and a perfusion catheter placed directly into the left carotid artery. Bilateral axillary arterial perfusion through the grafts was successful in all patients. There were no early or late deaths and no incidence of neurologic deficit. There were no complications related to cannulation of the axillary arteries. Bleeding, temporary renal failure, acute respiratory distress syndrome, and graft infection occurred in one patient each; all recovered from these complications. Bilateral axillary arterial perfusion is feasible and effective for brain protection during surgery on the ascending aorta and aortic arch.     

Cerebral protection during surgery of the thoracic aorta: a review.

Operations on the aortic arch remain a major challenge for the cardiac surgeon and neurologic injuries represent the most feared complication. During the last decades, different cerebral protection techniques, including deep hypothermic circulatory arrest, and retrograde and antegrade cerebral perfusion have been introduced into clinical practice to reduce the incidence of such complications. All three methods present advantages and disadvantages. In this review, the theoretical impact of the current methods of brain protection is reported and discussed.     

Endovascular clamping of porcelain aorta in aortic valve surgery using Foley Catheter

Unclampable calcified aorta is an uncommon condition that all cardiac surgeons may encounter and performing aortic valve surgery in this condition with a non cross-clamping technique of using Foley Catheter has rarely been reported. Aortic valve surgery invariably becomes a high-risk, challenging procedure to cardiac surgeon or even a contraindication to surgery when the ascending aorta cannot be clamped due to extensive calcification precluding safe dissection and clamping. We describe and recommend a non cross-clamping technique of using Foley Catheter and report it successful use in two patients who underwent aortic valve replacement with "porcelain" unclampable aorta.     

MRI of the thoracic aorta

Diseases of the thoracic aorta cause significant morbidity and mortality and can result in potentially catastrophic consequences. Conventional digital subtraction angiography (DSA) has been the gold standard for imaging for many years; however, this is associated with adverse effects and provides only limited information about vessel morphology. DSA is used primarily as a first-line investigation in the setting of trauma. Several other techniques also have been used in recent years, including CT and MRI. This article focuses primarily on the latter.     

The Williams-Beuren syndrome: reconstruction of the thoracic aorta combining surgery and endovascular treatment

The Williams-Beuren syndrome is the association of elf-like facies, mental retardation with cardiovascular anomalies, the most common of which is supravalvular aortic stenosis. This lesion may be focal or associated with hypoplasia of the distal aorta. The treatment is surgical and the role of interventional cardiological treatment is poorly defined. The authors report the case of a child with typical Williams-Beuren syndrome. An initial, very localised surgical aortic repair was performed at 3 months of age for a discrete supravalvular aortic stenosis. Two months later, a second operation was required for a new stenosis of the distal anastomosis associated with marked hypoplasia of the aortic arch. The progressive constitution of an isthmic coarctation led to the percutaneous implantation of a stent followed by two balloon dilatations. Only the first two endoluminal procedures successfully reduced the transisthmic pressure gradient. An antihypertensive treatment was given and regular echocardiography allows monitoring of the adaptation of the left ventricle.