Natural history of descending thoracic and thoracoabdominal aortic aneurysms

ObjectivesElucidating critical aortic diameters at which natural complications (rupture, dissection, and death) occur is of paramount importance to guide timely surgical intervention. Natural history knowledge for descending thoracic and thoracoabdominal aortic aneurysms is sparse. Our small early studies recommended repairing descending thoracic and thoracoabdominal aortic aneurysms before a critical diameter of 7.0 cm. We focus exclusively on a large number of descending thoracic and thoracoabdominal aortic aneurysms followed over time, enabling a more detailed analysis with greater granularity across aortic sizes.MethodsAortic diameters and long-term complications of 907 patients with descending thoracic and thoracoabdominal aortic aneurysms were reviewed. Growth rates (instrumental variables approach), yearly complication rates, 5-year event-free survival (Kaplan–Meier), and risk of complications as a function of aortic height index (aortic diameter [centimeters]/height [meters]) (competing-risks regression) were calculated.ResultsEstimated mean growth rate of descending thoracic and thoracoabdominal aortic aneurysms was 0.19 cm/year, increasing with increasing aortic size. Median size at acute type B dissection was 4.1 cm. Some 80% of dissections occurred below 5 cm, whereas 93% of ruptures occurred above 5 cm. Descending thoracic and thoracoabdominal aortic aneurysm diameter 6 cm or greater was associated with a 19% yearly rate of rupture, dissection, or death. Five-year complication-free survival progressively decreased with increasing aortic height index. Hazard of complications showed a 6-fold increase at an aortic height index of 4.2 or greater compared with an aortic height index of 3.0 to 3.5 (P < .05). The probability of fatal complications (aortic rupture or death) increased sharply at 2 hinge points: 6.0 and 6.5 cm.ConclusionsAcute type B dissections occur frequently at small aortic sizes; thus, prophylactic size-based surgery may not afford a means for dissection protection. However, fatal complications increase dramatically at 6.0 cm, suggesting that preemptive intervention before that criterion can save lives.     

Evolution of surgical treatment of thoracic aortic aneurysms

Aneurysms of the thoracic aorta remain a challenge to surgeons. My early experience began in 1950, when I excised a large aneurysm in one of Dr Alfred Blalock's patients. The patient survived and was cured. This experience convinced me that aortic aneurysms could be treated successfully by aggressive surgical means. Treatment, however, has changed from the early emphasis on excision of the lesion to the present belief in restoration of circulatory continuity using a suitable Dacron graft, or endoaneurysmorrhaphy.     

Natural history and indications for surgery in carotid stenosis

Atherosclerotic stenoses of the internal carotid artery are often the underlying cause for ischemic stroke. Several studies show a strong correlation between the grade of stenosis and stroke risk. When cerebral symptoms occur in patients with a carotid artery stenosis of 60% or more the risk of stroke within the following 12 months is over 10%. Large randomised studies show that patients with a high grade carotid artery stenosis benefit clearly from carotid endarterectomy. Surgical treatment reduces stroke risk by more than 70% in these patients. Symptomatic patients with stenoses less than 40% do not benefit by endarterectomy even when surgical complication rate is low. The benefit of carotid endarterectomy is proven for asymptomatic stenoses, too. In asymptomatic patients, however, an operative procedure is justified only when surgical complication rate is 3% or less.     

Lateral ventricular arteriovenous malformations: Natural history and surgical indications

Summary The authors report 21 cases of lateral ventricular arteriovenous malformation (AVM) focusing on their natural history and surgical indications. Eighteen of 21 patients (86%) had bleedings prior to admission. We performed definitive surgery in 9 patients and conservative treatment in 12 patients.In 7 of 9 patients (78%) in the operative group and in 5 of 12 patients (42%) in the non-operative group, the nidus of the AVM was less than 4 cm in diameter. The other 2 AVMs in the operative group, more than 4 cm in diameter, were located in the temporal lobe and widely extended to the temporal horn of the lateral ventricle. The nidi of the AVMs were totally removed in all 9 cases in the operative group. All patients have been doing well except one who had a mental breakdown 6 years after surgery.In 10 patients in the non-operative group, AVMs were located in the left cerebral hemispheres. Three patients in the non-operative group had rebleeding of the AVM. Two of the 12 patients in the non-operative group (17%) died of the recurrent haemorrhages. The rate of bleeding of the lateral ventricular AVM seems to be higher than that of the cerebral cortical AVM, but the mortality due to recurrent bleeding might be similar between the two.The operative indications we made depended on the sizes and locations of the AVMs. For AVMs in the temporal horn, even though they were large, we performed total removals of the nidi and had good results. We did not perform any definitive surgery for AVMs more than 4 cm in diameter except for those in the temporal horn. The mortality and morbidity of the 21 cases were 10% and 14%, respectively. Patients with AVMs in the temporal horn and patients with small AVMs in the frontal horn were good candidates for definitive surgery. We undertook conservative treatment for patients with large AVMs, and the results were acceptable.     

Endoluminal versus open treatment of descending thoracic aortic aneurysms

PURPOSE: This report describes the authors' initial experience with the Excluder thoracic endoprosthesis (W. L. Gore and Associates, Inc, Flagstaff, Ariz) and the thoracic Talent endoprosthesis (Medtronic AVE, Sunrise, Fla) and their safety and efficacy in the primary endovascular repair of descending thoracic aortic aneurysms (TAAs). In addition, comparison with a historic nonrandomized cohort of patients that had undergone open repair of descending TAAs is reported. PATIENTS AND METHODS: Repair of TAA (mean diameter, 68 +/- 22 mm) was attempted in 19 patients with the Excluder (n = 14) and the Talent (n = 5) endoprostheses between March 1999 and January 2000. This group was compared with a historic nonrandomized cohort of 10 patients that had undergone open repair of anatomically similar descending TAA (mean diameter, 74 +/- 22 mm) between January 1996 and January 1998. The mean age in the endovascular group was 70.6 +/- 5.3 years versus 70.1 +/- 4.5 years in the historic open group. All the procedures were performed in a standard operating room with angiographic capabilities. In the historic open group, each standard tube graft repair of descending TAA was performed by one of three staff surgeons. RESULTS: Endograft deployment was successful in 18 patients (95%). The procedure was aborted in one patient (Excluder) because of small iliac arteries and access difficulty. The average operative time was 155 +/- 62 minutes, with a mean blood loss of 325 +/- 353 mL (versus 256 +/- 102 minutes and 1205 +/- 1493 mL, respectively, in the open group). Eight patients needed the planned use of more than one component for enhanced sealing or additional length in the endovascular group. No type I endoleaks were identified on the intraoperative completion angiography. One perioperative mortality occurred in the endovascular group and the open group. In the endovascular group, other complications included retroperitoneal hematoma and external iliac artery dissection (n = 1), lymphocele (n = 1), and common femoral artery pseudoaneurysm (n = 1). In the open group, other complications included ischemic colitis (n = 1), severe renal insufficiency (n = 2), wound infection (n = 1), and stroke (n = 1). In the endovascular group, the length of stay was 6.2 +/- 3.3 days (range, 1 to 13 days), with only nine patients needing intensive care, whereas in the open group, the length of stay was 16.3 +/- 6.7 days, with all patients needing intensive care. Endoleaks, graft migrations, or ruptures were not seen on the 1-month, 6-month, and 12-month follow-up computed tomographic scans in the endovascular group. On the average, aneurysm size decreased from 68 +/- 22 mm to 58 +/- 13 mm, to 51 +/- 14 mm, and to 49 +/- 12 mm at 1, 6, and 12 months after endovascular repair, respectively. No spinal cord ischemia was seen in either group. CONCLUSION: The endoluminal repair was effective in exclusion of descending TAAs from the systemic circulation in this selected group of patients. In this short-term follow-up, compared with the nonrandomized historic cohort of open descending TAA repair, the endovascular group had significantly shorter operating times and hospital and intensive care unit stays and lower operative blood loss. Further follow-up and continued assessment of the long-term durability of these devices in elective and emergency circumstances are warranted.     

Debatable questions in the surgical treatment of thoracic aortic aneurysms

Some controversies in the surgical approach to thoracic aortic aneurysms are discussed. The author recommends: to perform echocardiography in patients with aortic aneurysms for detection of intracardiac pathology which may complicate the postoperative course; to combine thoracic aortography with selective coronary angiography in patients with thoracic aortic aneurysm for diagnosis of coronary artery disease; to operate asymptomatic fusiform aneurysm that measure twice or more the size of the normal aorta; to resect and replace dissections of the ascending aorta during cardio-pulmonary bypass; and to use active shunts during resection of the descending and thoraco-abdominal aneurysm.     

Natural history of minimal aortic injury following blunt thoracic aortic trauma

Background

Endovascular repair of blunt traumatic thoracic aortic injuries (BTAI) is common at most trauma centres, with excellent results. However, little is known regarding which injuries do not require intervention. We reviewed the natural history of untreated patients with minimal aortic injury (MAI) at our centre.

Methods

We conducted a retrospective database review to identify all patients with a BTAI between October 2008 and March 2010. The cohort comprised patients initially untreated because of the lesser degree of injury of an MAI. We reviewed initial and follow-up computed tomography (CT) scans and clinical information.

Results

We identified 69 patients with a BTAI during the study period; 10 were initially untreated and were included in this study. Degree of injury included intimal flaps (n = 7, 70%), pseudoaneurysms with minimal hematoma (n = 2, 20%) and circumferential intimal tear (n = 1, 10%). Six (60%) patients were male, and the median age was 40 years. Duration of clinical follow-up ranged from 1 month to 6 years (median 2 mo) after discharge, whereas CT radiologic follow-up ranged from 1 week to 6 years (median 6 wk). Seven (70%) patients had complete resolution or stabilization of their MAI, 1 (10%) with circumferential intimal tear showed extension of the injury at 8 weeks postinjury and underwent successful repair, and 2 (20%) were lost to follow-up.

Conclusion

There appears to be a subset of patients with BTAI who require no surgical intervention. This includes those with limited intimal flaps, which often resolve. Radiologic surveillance is mandatory to ensure MAI resolution and identify any progression that might prompt repair.     

Neuroleptanesthesia versus thoracic epidural anesthesia for abdominal aortic surgery

The hemodynamic consequences of abdominal aortic surgery with infrarenal cross-clamping were studied in 21 patients randomized in two groups. In Group I (11 patients), neuroleptanesthesia was utilized, while Group II (10 patients) received thoracic epidural anesthesia at the T8-9 level. Hemodynamic measurements were performed using Swan-Ganz catheters during the surgical procedures in all patients, with special attention to the periods of clamping and unclamping of the abdominal aorta. The thoracic epidural anesthesia group was characterized by greater hemodynamic stability during surgery, while patients in the neuroleptanesthesia group had significant lability of blood pressure, heart rate, and cardiac index. Nevertheless, in the two groups of patients, it is suggested that cardiac function was unfitted to the tissue oxygen demand after unclamping of the aortic prosthesis because the saturation in oxygen of the mixed venous blood and an increase in arteriovenous difference in oxygen were documented. These results point out that, whatever the anesthesia technique, the critical period in abdominal surgery could be aortic unclamping.     

Descending thoracic aortic aneurysms: surgical treatment with the Gott shunt.

Over the past 16 years, 267 consecutive patients underwent surgery for a descending thoracic aortic aneurysm. To provide optimal protection of surrounding organs during aortic occlusion, a 9-mm Gott shunt was used for distal perfusion in all cases. The shunt was placed preferentially between the ascending aorta and the descending aorta; however, alternative sites of proximal and distal cannulation were chosen according to the location and the extent of the aneurysmal disease and the presence of a concomitant aneurysm along the aortic conduit. In one-third of the patients, a flowmeter on the shunt recorded shunt flows, which varied from 1100 mL/min to 4900 mL/min (mean 2526 mL/min). Because the highest shunt flows were obtained with proximal systolic pressures lower than 140 mm Hg, nitroglycerin and nitroprussate were used routinely to improve distal perfusion by arterial vasodilation and release of proximal organs from a circulatory overload. The mean aortic cross-clamp time was 33 minutes for the entire series but was reduced to 25 minutes for the last 140 patients. The hospital death rate was 14.6% overall (12.2% if ruptured aneurysms were excluded). Of the 267 patients, 260 survived the operation and underwent clinical neurologic assessment. No paraplegia or other spinal-cord ischemic deficit occurred.     

Contemporary results of open surgical repair of descending thoracic aortic aneurysms

Considerable progress has been made in the refinement of operative strategies to repair descending thoracic aortic aneurysms (TAA). While no single strategy has totally eliminated the postoperative morbidities of renovisceral and spinal cord ischemic complications, contemporary reports from centers of excellence detail admirable rates of overall risk in the 5-10% range. Balancing these risks represents a clinical dilemma for the aortic surgeon and a thoughtful, logical risk analysis of the individual patient presentation is clearly warranted before TAA repair. In this article, we review surgical approaches to TAA and adjunctive methods, examine the reports from centers of excellence, and elucidate the challenges yet to be overcome in the management of patients with aneurysms of the descending thoracic aorta.     

Hybrid procedures combining conventional and thoracic endovascular aortic repair for thoracic aortic aneurysms

Purpose  

To minimize surgical invasiveness for extensive aortic aneurysms and expand the indications for thoracic endovascular aortic repair (TEVAR), we evaluated outcomes of hybrid procedures combining conventional surgical aortic repair and TEVAR for thoracic aortic aneurysms.