Endovascular stent graft repair for aneurysms on the descending thoracic aorta

BACKGROUND: The traditional treatment of aneurysms of the descending thoracic aorta includes posterolateral thoracotomy and aortic replacement with a prosthetic graft. In this study, we report our experiences and results in endovascular stent graft placement as an alternative to surgical repair. METHODS: Between January 1989 and July 1997, a total of 68 patients (24 women) underwent replacement of the thoracic aorta. Mean age at operation was 51 years. Fifty-eight patients underwent conventional surgical treatment. All of these patients were suitable candidates for endovascular stenting; however, no stent graft material was available at the time of operation. Ten patients (1 chronic dissection, 9 atherosclerotic aneurysm) received in the past 8 months the first commercially manufactured endovascular stent graft. The mean diameter of the aneurysms in this group was 7 cm (range, 6 to 8 cm). Two stent patients were operated on using only spinal cord analgesia. All stent grafts were custom designed for each of the 10 patients. RESULTS: The 30-day mortality in the conventional group was 31% versus 10% in the stent group. Mean length of intervention was 320 minutes in the conventional group versus 150 minutes in the endovascular group. Spinal cord injury occurred in 5 patients (12%) in the surgical group, whereas none of the stented patients developed any neurologic sequelae. Mean intensive care unit stay was 13 days, followed by a mean of 10 days on a ward in the first group compared to 4 days in the intensive care unit and 6 days on the ward in the stent group. One stent was required in 2 patients, two stents were required in 3 patients, and four stents were deployed in 5 patients of our series. Five patients required transposition of the left subclavian artery to achieve a sufficient neck for the proximal placement of the stent. There was complete thrombosis of the thoracic aortic aneurysm surrounding the stent graft in 8 patients (80%). Two patients required restenting as a result of leakage (20%). Stent graft placing was performed through the femoral artery in 8 patients, whereas access was only achieved through the abdominal aorta in 2 patients. CONCLUSIONS: These preliminary results demonstrate that endovascular stent graft replacement might be a promising, cheaper, and safe alternative method in selected patients with descending thoracic aneurysms.     

Differential expression of heat shock proteins in normal and failing human hearts

OBJECTIVE: To predict spinal cord ischemia after endovascular stent graft repair of descending thoracic aortic aneurysms, temporary interruption of the intercostal arteries (including the aneurysm) was performed by placement of a novel retrievable stent graft (Retriever) in the aorta under evoked spinal cord potential monitoring. METHODS: From February 1995 to October 1997, endovascular stent graft repair of descending thoracic aortic aneurysms was performed in 49 patients after informed consent was obtained. In 16 patients with aneurysms located in the middle and distal segment of the descending aorta, the Retriever was placed temporarily before stent graft deployment. The Retriever consisted of two units of self-expanding zigzag stents connected in tandem with stainless steel struts. Each strut was collected in a bundle fixed to a pushing rod, and the stent framework was lined with an expanded polytetrafluoroethylene sheet. The Retriever was delivered beyond the aneurysm through a sheath and was retracted into the sheath 20 minutes later. A stent graft for permanent use was deployed in patients whose predeployment test results with the Retriever were favorable. Evoked spinal cord potential was monitored throughout placement of the Retriever and stent grafting until the next day. RESULTS: The Retriever was placed in 17 aneurysms in 16 patients. There were no changes in amplitude or latency of evoked spinal cord potential records obtained before or during Retriever placement. After withdrawal of the Retriever, all aneurysms were excluded from circulation immediately after permanent stent grafting. There were no changes in evoked spinal cord potential, nor were neurologic deficits seen after stent graft deployment in any patient. CONCLUSIONS: These results suggest that predeployment testing with the Retriever under evoked spinal cord potential monitoring is promising as a predictor of spinal cord ischemia in candidates for stent graft repair of thoracic aortic aneurysms.     

Abdominal aortic aneurysms in sheep: prevention of rupture with endoluminal stent-grafts

PURPOSE: The authors evaluated the ability of an aortic balloon-expandable endovascular stent-graft to prevent rupture in a model of spontaneously rupturing abdominal aortic aneurysms in sheep. MATERIALS AND METHODS: Aneurysms were created in 16 sheep by inserting a 60 x 18-mm segment of the left internal jugular vein, end-to-end anastomosed, to the sectioned infrarenal abdominal aorta. The sheep were randomly assigned into two groups; eight animals underwent endovascular implantation of an 80 x 12-mm balloon expandable stent-graft (group A), and eight were only followed up (group B). RESULTS: In group B, seven of eight animals had died of aneurysmal rupture by 3 months. In group A, six of the eight aortic aneurysms were immediately excluded, and six animals were alive at 3 months without rupture. The 3-month survival rate was 100% in group A and 12% in group B (P = .0023). Macro- and microscopic analysis of the section of the aorta in which the stent-graft had been placed revealed rapid retraction of the aneurysmal sac. CONCLUSION: Placement of an endovascular stent-graft induced regression of a branchless aneurysm and prevented rupture.     

Stent-graft placement procedures for descending thoracic aortic aneurysms

Descending thoracic aortic aneurysms most often are caused by arteriosclerosis and appear most frequently in elderly males. These patients often are asymptomatic, but they may experience symptoms related to compression of adjacent thoracic structures, or they may present for treatment when their-aneurysms rupture. Open surgical resections and repairs of descending thoracic aortic aneurysms are associated with bleeding, paraplegia, strokes, renal insufficiency, and the need for prolonged ventilatory support in the postoperative period. At Stanford (Calif) University Hospital, surgeons are placing endovascular stent-grafts in patients with descending thoracic aortic aneurysms who meet specific anatomic selection criteria. This new treatment modality provides patients with a less invasive, less hazardous, and potentially less expensive alternative to open surgical resection and repair procedures. Preoperative teaching and skilled perioperative nursing care are essential for positive patient outcomes with stent-graft treatment of descending thoracic aortic aneurysms.     

Management of failed and infected axillofemoral grafts

PURPOSE: The purpose of this study was to review the treatment of patients with failed or infected axillofemoral bypass grafts and to determine the efficacy of remedial procedures in maintaining graft patency and limb preservation. METHODS: Thirty-four patients with 37 failed or infected axillofemoral grafts were retrospectively reviewed. In nine cases there was no attempt at revascularization, and in the remaining 28 cases, a total of 52 remedial procedures was performed. Nine were performed in patients with graft infection and 43 in patients with graft thrombosis. In patients with axillofemoral graft failure, 21 thrombectomies, 13 graft revisions, and 9 secondary reconstructions were performed. Eighty-eight percent of patients were monitored at least 2 years or until graft failure. RESULTS: Eight of nine patients receiving no remedial procedure required major amputation. The limb salvage rate was 64% +/- 11% at 30 months in the 25 patients undergoing remedial procedures. Twenty-eight percent of failed axillofemoral grafts remained patent at 2 years after initial failure with single or multiple thrombectomies or revisions. Life-table primary patency after secondary reconstructions (81% +/- 10.9% at 24 months) was significantly better than after thrombectomy alone (10% +/- 4.2% at 24 months) or graft revision (16% +/- 10.6% at 24 months) by log-rank test (p < 0.001 and p < 0.005, respectively). Patients undergoing reconstruction with descending thoracic aorta to femoral artery bypass had an 89% +/- 11% patency rate at 24 months. Graft infection resulted in a perioperative mortality rate of 22% and amputation in 57% of survivors. CONCLUSION: Axillofemoral graft failure most often results in limb loss without remedial procedures. Thrombectomy and revision procedures had poor long-term patency rates and salvaged only a minority of grafts despite multiple procedures. Reconstruction by use of an alternate source of inflow such as the descending thoracic aorta resulted in better long-term patency rates in patients well enough to tolerate a major reoperative procedure.     

Extension of the "elephant trunk" technique in complex aortic pathology: the "bidirectional" option

BACKGROUND: The "elephant trunk" technique, using a free-floating vascular prosthesis, was originally described to facilitate a subsequent operation on the downstream aorta. We developed an additional refinement of this technique, called the "bidirectional elephant trunk." This option may represent an interesting tool in more complex aortic operations, especially when the descending aorta has to be replaced first in patients with concomitant pathology of the ascending aorta or of the aortic arch. METHODS: The initial operation is performed through a left thoracotomy. The proximal elephant trunk is created by invaginating the future aortic arch graft into the descending aortic graft. The proximal anastomosis between the doubled graft and the proximal descending aorta is performed first. During construction of the distal anastomosis, a distal elephant trunk may be inserted likewise. If the aortic arch and ascending aorta have to be replaced later, this second step is performed through a median sternotomy. The free-floating arch graft is pulled out of the proximal descending aorta with a nerve hook, unfolded, and used for total arch replacement. RESULTS: This technique was used successfully in 3 patients without mortality. No major complications were observed excepted persistent hoarseness in a patient with preoperative paresis of the recurrent nerve. No perfusion problems due to the unfolding of the free-floating graft occurred during the second operation. CONCLUSIONS: The bidirectional elephant trunk technique is an interesting option that may be suitable for patients presenting with a complex pathology of the whole thoracic aorta when the descending segment has to be replaced first.     

Transthoracic repair of innominate and common carotid artery disease: immediate and long-term outcome for 100 consecutive surgical reconstructions

PURPOSE: This is a review of 100 consecutive supraaortic trunk reconstructions (SAT) performed over 16 years. METHODS: There were eight innominate endarterectomies and 92 bypass procedures based on the thoracic aorta (n = 86) or proximal innominate artery (n = 6) in 98 patients 24 to 79 years of age. Indications included cerebrovascular ischemia in 83 and upper extremity ischemia in four. Thirteen patients were asymptomatic. An innominate lesion was bypassed in 78 cases. The left common carotid and left subclavian arteries required reconstruction in 38 and nine patients, respectively. Multiple trunks were reconstructed by direct bypass grafting in 35. Approach was via median sternotomy in 92, partial sternotomy in six, and left thoracotomy in two. Seven patients underwent concomitant cardiac surgery. RESULTS: Eight deaths and eight nonfatal strokes occurred, for a combined stroke/death rate of 16%. The operative mortality rate was 6% for SAT and 29% for SAT/cardiac operations. Perioperative complications included two asymptomatic graft occlusions, three nonfatal myocardial infarctions, seven significant pulmonary complications, three sternal wound infections, and one recurrent laryngeal nerve injury. Follow-up ranged from 1 to 184 months (mean, 51 +/- 4.8 months). Eight patients were lost to follow-up. Twenty-one late deaths occurred. Two SATs required late revision. The cumulative primary patency rates at 5 and 10 years were 94% +/- 3% and 88% +/- 6%, respectively. The stroke-free survival rates at 5 and 10 years were 87% +/- 4% and 81% +/- 7%, respectively. Patients who survived beyond 30 days had a median stroke-free life expectancy of 10 years, 7 months (SE, 6%). CONCLUSIONS: Direct reconstruction of complex symptomatic SAT lesions can be performed with acceptable death/stroke rates and with long-term patient benefit. Asymptomatic lesions in patients who have significant concomitant conditions should be managed with a less-morbid cervical or endovascular approach, even if long-term outcome of the latter is inferior.     

In vivo morphology of woven, collagen-sealed Dacron prostheses in the thoracic aorta

BACKGROUND: Long-term changes in knitted Dacron grafts inserted into the infrarenal aorta have been addressed by a number of studies indicating their potential for postoperative dilatation. In contrast, the behavior of woven, collagen-presealed, double-velour Dacron grafts used to replace the thoracic aorta is not known. METHODS: Forty-five patients were examined at a mean of 32.4 +/- 14.8 months after insertion of woven, collagen-coated, Dacron double-velour prostheses (Meadox woven with Hemashield, Meadox, Oakland, NJ) in the thoracic position under highly standardized conditions using spiral computed tomography. RESULTS: Compared with a manufactured diameter of 26 mm, all grafts showed an increase of 1 to 5 mm (mean, 3.0 +/- 1.2 mm [11.6% +/- 4.4%]; p < 0.0001) with greater enlargement of the ascending than of the descending aortic portions (p = not significant). A further statistically significant progressive dilatation failed to occur. Degenerative changes, including false aneurysm formation, could be excluded. CONCLUSIONS: Woven, collagen-coated Dacron prostheses are considered a safe replacement material for the thoracic aorta.     

Electronic access to mouse tumor data: the Mouse Tumor Biology Database (MTB) project

BACKGROUND: Single-stage extensive replacement of the thoracic aorta usually involves a period of circulatory arrest with performance of the graft-to-lower descending thoracic aorta anastomosis before performing the anastomosis to the arch vessels. To minimize the period of brain ischemia and reduce the potential for neurologic injury, we developed an alternative technique. METHODS: In 6 patients with extensive aneurysms involving the entire thoracic aorta, exposure was obtained via a bilateral thoracotomy in the anterior fourth intercostal space with transverse sternotomy. A 10-mm graft was anastomosed to the aortic graft, opposite the site of the planned anastomosis to the arch vessels. During a single period of circulatory arrest (34-46 minutes), the aortic graft was attached to a cuff of aorta containing the arch vessels. The graft was then clamped on either side, and the arch was perfused with cold blood for 20 to 36 minutes. After the distal aortic anastomosis was completed, antegrade perfusion was established via the 10-mm graft. The proximal aortic anastomosis was performed last. RESULTS: No patient sustained a permanent neurologic deficit. All 6 patients were discharged from the hospital. CONCLUSIONS: The "arch-first" technique, combined with a bilateral transverse thoracotomy, allows expeditious replacement of the thoracic aorta with an acceptable interval of hypothermic circulatory arrest and minimizes the risk of retrograde atheroembolism by establishing antegrade perfusion.     

Clinical decision making and operative approaches to thoracic aortic aneurysms

The care of the patient with thoracic aneurysms is quite complicated. The decision to treat an aneurysm must be based on the risk of rupture and the patient's life expectancy. The preoperative evaluation must include detailed imaging to allow proper preoperative planning. This is especially important to determine the need for hypothermic circulatory arrest or the potential to treat a descending aneurysm with an endovascular approach. Thorough preoperative preparation and intraoperative care are as important as surgical decision making and meticulous technique. Although significant advances have been made in operative approaches, cerebral and myocardial preservation, and postoperative care, the management of complicated aneurysms of the thoracic aorta is frequently a humbling experience.     

Minimal invasive therapy of aneurysms of the superficial femoral artery and the popliteal artery

Percutaneous stent placement has been described for treatment of aneurysms as an alternative to surgical therapy. Literature reports of percutaneous minimal invasive therapy of peripheral aneurysms shall be reviewed and compared with our own results. Six male patients (51-69 years) with femoropopliteal occlusions related to aneurysms were treated percutaneously. In two cases Wallstents and in four cases polyester-covered nitinol stents were applicated. A clinical investigation including doppler-ultrasound was performed 24 hrs, 1, 3, 6, 12 and 24 months after the intervention. Stent placement succeeded in all cases. No adjunctive surgical treatment was necessary. Ankle-brachial-index (ABI) improved from 0.22 +/- 0.2 before to 0.74 +/- 0.2 24 hours after the intervention. One patient was lost for follow-up (Wallstent). A decrease of ABI and additional intraarterial angiography revealed stent-graft occlusion within one month (n = 2) and within three months (n = 1). One of these cases was successfully recanalized with local fibrinolysis therapy. In three patients patency of the stent persisted for 24 (+/- 2) months follow-up with three-vessel-supply of the calf. These results warrant further investigations for this minimal invasive method of percutaneous stent deployment as an alternative to surgical bypass treatment of femoropopliteal aneurysms. Time of hospitalization was reduced. At this time, surgical treatment of peripheral vascular aneurysms is gold standard.     

Endovascular management of traumatic infrarenal abdominal aortic dissection

Dissection is a recognized finding after blunt trauma to the abdominal aorta. Immediate and long-term prognosis is poor without surgical treatment especially since most patients present severe associated injuries. On the basis of encouraging results using endovascular techniques to treat experimental dissection of the descending thoracic aorta, we treated three patients with traumatic infrarenal abdominal aortic dissection by percutaneous stent placement. There were two men 34 and 41 years of age and one 89-year-old woman. In all patients, dissection began in the infrarenal portion of the aorta and extended into the iliac arteries. All patients had multiple associated injuries. The main symptoms were acute abdominal pain (two patients) and ischemia of the lower extremities (two patients). Diagnosis was missed in one patient despite exploratory laparotomy for an associated injury. Two patients were treated in the acute phase by placement of a self-expanding endovascular prosthesis at the aortoiliac level. The third patient was treated in the chronic phase by placement of a balloon-expandable endovascular stent. All procedures were performed uneventfully by femoral route. Success of treatment was confirmed by arteriography and computed tomography (CT) scan demonstrating obliteration of the dissection. Upon late follow-up examination, all patients were in satisfactory condition, with normal Doppler ultrasound findings. These findings confirm experimental studies using endovascular treatment for dissection of the descending thoracic aorta and are promising for future clinical management.     

Endovascular stent graft repair of aortic aneurysms

Vascular surgeons are increasingly encountering older patients with large aneurysms associated with severe comorbid conditions. This situation can increase operative morbidity and elevate the mortality rate of aortic surgery over 60%. With some frequency many patients will represent a prohibitive risk for conventional graft replacement. The endoluminal treatment of 110 patients has proved to be feasible and may represent an alternative solution. One hundred six of the patients had an abdominal aortic aneurysm and in four patients, the thoracic aorta was involved. All of them underwent endoluminal repair for the aortic pathology using the combination of stents and grafts in aorto-aortic or aorto-iliac position, with straight, tapered, or bifurcated stent-graft devices. The results are as follows: Initial success was 84% in aorto-aortic abdominal devices and 100% in aorto-aortic thoracic devices. In aorto-iliac devices, initial success was 75%. Late success rates were 62% of the initial group and 80% of the initially successful group.     

Endovascular treatment of abdominal aortic aneurysms. Morphology of aneurysms as one of the deciding indicating factors

Endovascular treatment of aneurysms of the abdominal aorta is based on intravascular bridging of the aneurysm using of an endovascular prosthesis. The prosthesis must be safely anchored above and below the sac of the aneurysm in the non-dilated artery. Therefore the indication of endovascular treatment depends on the morphology of the aneurysm. The objective of the work was to analyse the morphology of the aneurysm with regard to the possibility of endovascular treatment. The morphology of the aneurysm was evaluated with regard to the angiographic examination and examination by computed tomography. The following parameters were investigated: diameter and length of the proximal and distal neck, diameter of the sac in two planes, diameter and tortousity of the iliac arteries, tortousity of the infrarenal aorta. A total of 70 patients with aneurysms of the abdominal aorta were examined. The patients were divided into three groups according to the morphology of the aneurysm. I. infrarenal aneurysms not affecting common iliac artery (n = 20) 28.5%, II. infrarenal aneurysms affecting common iliac artery (n = 38) 54.2%, III. juxtarenal aneurysms regardless of the affection of common iliac arteries (n = 12) 17.1%. Of the total of 70 examined patients 24 (34.2%) with infrarenal aneurysm and 6 (8.57%) with juxtarenal aneurysm were suitable for endovascular treatment.     

Effect of surfactant on respiratory failure associated with thoracic aneurysm surgery

OBJECTIVE: To study the effects of surfactant administration on the left lung after surgical repair of descending aortic aneurysms on postoperative respiratory failure. DESIGN: Randomized, prospective, controlled study. SETTING: Clinical investigation. PATIENTS: Eleven patients with respiratory failure associated with thoracic aneurysm surgery. INTERVENTION: Eleven adult patients with acute respiratory failure (PaO2/FIO2 <300 torr [<40 kPa]) after surgical repair of descending aortic aneurysms. The artificial surfactant (30 mg/kg) was given to the operated side of the lung by intrabronchial instillation in six patients (surfactant group), whereas nothing was instilled in the other five patients (control group). MEASUREMENTS AND MAIN RESULTS: Hemodynamic parameters, blood gas, and peak inspiratory pressure were measured at the end of surgery, before surfactant instillation, and at 2, 6, 12, 24, and 48 hrs after surfactant instillation. At the end of surgery, the mean +/- SEM values of the PaO2/FIO2 ratio were 204 +/- 25 torr (27.2 +/- 3.3 kPa) in the surfactant group and 240 +/- 26 torr (32.0 +/- 3.5 kPa) in the control group. After 2, 6, 12, and 48 hrs, improvements in the PaO2/FIO2 ratios were observed in the surfactant group, whereas the control group showed no improvement. Two hours after surfactant instillation, the mean value in the PaO2/FIO2 ratio was significantly higher in the surfactant group (318 +/- 24 torr [42.4 +/- 3.2 kPa]) (p < .05) compared with the control group values (240 +/- 34 torr [32 +/- 4.5 kPa]). CONCLUSION: Surfactant administration immediately after surgery restored gas exchange in postoperative respiratory failure associated with thoracic aneurysm surgery.     

A pseudoaneurysm after repair of thoraco-abdominal aortic aneurysm

We report a 63-year-old female patient developing a pseudoaneurysm three years after patch-plasty of an aneurysm located at the distal thoracic aorta. Redo-operation was performed including total replacement of the descending thoracic aorta with reimplantation of distal intercostal arteries using small-caliber interposition grafts. This case presentation underlines the ineffectiveness of patch repair for the treatment of aortic aneurysms. Furthermore, the surgical technique of reimplantation of intercostal arteries using a separate graft is discussed.     

Hypothermic circulatory arrest does not increase the risk of ascending thoracic aortic aneurysm resection

OBJECTIVE: The purpose of this study was to investigate the safety and efficacy of a period of deep hypothermic circulatory arrest (DHCA) during elective replacement of the ascending thoracic aorta. SUMMARY BACKGROUND DATA: DHCA has been implemented in ascending thoracic aortic aneurysm resection whenever the anatomy or pathology of the aorta or arch vessels prevents safe or adequate cross-clamping. Profound hypothermia and retrograde cerebral perfusion have been shown to be neurologically protective during ascending aortic replacement under circulatory arrest. METHODS: The authors conducted a retrospective analysis of 91 consecutive patients who underwent repair of chronic ascending thoracic aortic aneurysms from 1986 to present. The authors hypothesized that patients undergoing DHCA with or without retrograde cerebral perfusion during aneurysm repair were at no greater operative risk than patients who received aneurysm resection while on standard cardiopulmonary bypass. RESULTS: There were no significant differences in hospital mortality, stroke rate, or operative morbidity between patients repaired on DHCA when compared to those repaired on cardiopulmonary bypass. CONCLUSIONS: DHCA with or without retrograde cerebral perfusion does not result in increased morbidity or mortality during the resection of ascending thoracic aortic aneurysms. In fact, this technique may prevent damage to the arch vessels in select cases and avoid the possible complications associated with cross-clamping a friable or atherosclerotic aorta.     

Early and late outcome of operated and non-operated acute dissection of the descending aorta

OBJECTIVE: At present debate continues concerning the optimal mode of treatment for type B dissections. Controversies are mainly due to discordant results regarding survival following medical or surgical treatment. We assessed early and long-term outcome of acute dissection of the descending aorta treated by emergency aortic replacement, medical treatment or delayed surgery. METHODS: Between 1980 and 1995, 225 patients were hospitalized in the medical or surgical department of our institution with the diagnosis of acute type B aortic dissection. A total of 38 patients (16.8%) underwent replacement of the descending aorta within the first week after hospital admission. Primary indications for immediate surgery were: rupturing aneurysm (n = 15), diameter of the descending aorta (n = 13), malperfusion of the thoracoabdominal aorta (n = 8) and pseudocoarctation syndrome with uncontrollable hypertension (n = 2). All other patients (n = 187) underwent primary conservative treatment on the intensive care unit, including appropriate anti-hypertensive medication. In 12 of them, surgery was denied because of age or significant concomitant diseases. RESULTS: Hospital mortality after urgent or emergency surgery was 21% (8/38 patients) for the overall time period. There has been a significant decrease in hospital mortality during the last 5 year-period (12% versus 30% between 1980 and 1994). Causes of death were: cardiac failure in 3, bleeding complications in 2, postoperative mesenteric ischemia in 2 and septicemia in one patient. From the 30 operative survivors, 9 (30%) patients required further surgery on the native aorta after a mean follow-up of 48 +/- 13 months. Hospital mortality during conservative treatment was 17.6% (33/187 patients). Main causes of death were rupture in 14, thoraco-abdominal malperfusion in 13 and cardiac failure in 3 patients, whereas in 3 patients, the cause of death could not be evaluated. In this group, 9 patients had to be shifted to early surgery during the initial hospitalization because of impending rupture (n = 4), rapidly increasing diameter (n = 2) and suspicion of intestinal ischemia (n = 3). After hospital discharge, surgery for chronic dissection was performed in 47 patients, mainly because of expanding descending aortic aneurysm. Hospital mortality was 8% (4/47 patients). Actuarial survival rates after surgery during the first admission were 85 +/- 6% at 5 years and 61 +/- 8% at 10 years, versus 76 +/- 5 and 50 +/- 7% respectively, following conservative treatment (P < 0.001). CONCLUSION: Nowadays, acute type B dissection can be treated surgically with a reasonable perioperative risk. Despite aggressive anti-hypertensive treatment, hospital mortality of primary conservative treatment is still high and a substantial percentage of patients requires surgery during initial hospitalization. Main causes of death in both groups are rupture and abdominal malperfusion: therefore, closed clinical and radiologic assessment of the whole thoraco-abdominal aorta is of utmost importance. Long-term results are satisfying; unlimited radiographic follow-up allows for detection of potential severe complications and for proper planning of elective reoperations when indicated.     

Clinical results of endovascular stent graft repair for fifty cases of thoracic aortic aneurysms

Between February 1995 and December 1997, 50 cases (55 lesions) of thoracic aortic aneurysms including 20 cases of aortic dissections were treated with an endovascular technique using the stent grafts. All patients were treated in the operating room under general anesthesia and the stent grafts were implanted through 18 Fr. or 20 Fr. sheaths via femoral arteries under fluoroscopic guidance. The stent graft was composed of several units of self-expanding stainless-steel Z stents covered with an ultra-thin polyester fabric. Stent graft deployment was technically successful in 53 of 55 lesions (delivery success rate: 96.4%). Exclusion of the aneurysms and entry closing without endoleak were achieved within two weeks after the operation in 43 of 53 lesions (initial success rate: 81.1%). Endoleak was found in 10 lesions (minor endoleak: 8 and major endoleak: 2 lesions). Two patients died in the periopertive period of delivery failures as injury to external iliac artery and damage to the delivery sheath caused by tortuous and narrow access routes. Endovascular stent graft repair of thoracic aortic aneurysms is minimally invasive operation in comparison with conventional surgical graft replacement with extracorporeal circulation. These early results suggest that the stent graft repair is possibly safe and useful treatment for the patients of thoracic aortic aneurysms especially in high risk patients. However, careful long-term follow-up is necessary to prove the value and the effects of this endovascular treatment and improvement of the stent graft system and technical training of endovascular surgery for operators are required to reduce the delivery failure and to determine the stent graft repair is reliable treatment.     

Preoperative diagnosis of the thoracic aortic aneurysm by three-dimensional CT angiography

Serial eight patients with thoracic aortic aneurysms were evaluated by a newly developed three-dimensional CT angiography (3D-CT) from December 1992 to January 1993. The patients include 3 aortic dissections, 3 aortic arch aneurysms, one descending aortic aneurysm and one thoracoabdominal aortic aneurysm. The surgical treatment was performed after the evaluation of 3D-CT, and the operative findings were compared to the three-dimensional images reconstructed by 3D-CT in all patients. Three-dimensional displays were achieved using the unique method of data collection of the helical (spiral) scanner with continuous tube rotation and continuous table feed. A intravenous contrast material was used to image the thoracic aorta and major aortic branches with the single-breath-hold technique. Two and three-dimensional images reconstructed by 3D-CT were displayed within 10-20 minutes after the scanning. These three-dimensional images of the aortic lesions could be displayed in any angle we chose. Three-dimensional structures of the thoracic aorta and major aortic branches were clearly visualized and easily recognized by 3D-CT. These images were similar to the intraoperative findings and were quite useful to determine the operative procedure. The successful repair of thoracic aortic aneurysm was achieved in all cases. 3D-CT is a new and attractive modality to assess the vascular system. Although our experience is limited, 3D-CT may be a useful and powerful diagnostic method for the surgical treatment of thoracic aortic aneurysm.