Treatment of descending thoracic aneurysms by endovascular stent grafting

Surgical aspects of thoracic aortic aneurysms: A case series from a real-world setting

Background

The objective of the present study is to review different surgical features and treatment modalities of thoracic aortic aneurysms.

Methods

This was a retrospective study of 17 patients operated on for thoracic aortic aneurysm in the Department of Cardiovascular Surgery of the Military Hospital of Rabat (Morocco) over a 10-year period, from January 2007 to December 2016. All patients with aneurysms located in the thoracic aorta or extended to the abdominal aorta were included in the study.

Results

The mean age of the patients was 49 ± 6 years. 58% of the patients were symptomatic. 10 patients (62%) had an aneurysm of the ascending thoracic aorta and 2 patients had an aneurysm of the ascending aorta extended to the arch. In 2 patients, the aneurysm was located in the descending thoracic aorta. Three patients (18%) had a post-traumatic false aneurysm of the aortic isthmus. Six patients underwent a Bentall procedure. One patient underwent the Yacoub technique. Two patients underwent ascending aorta replacement using the Wheat technique. In addition, two patients underwent ascending aorta and arch replacement and five patients (29%) underwent descending thoracic aorta replacement. In-hospital mortality was 12%. Two patients (12%) developed paraplegia and two developed renal failure (12%).

Conclusion

Thoracic aortic aneurysms are a serious pathology requiring surgical treatment before complications arise. Replacement of the arch and the descending thoracic aorta still remain a challenge for cardiovascular surgeons because of neurological complications.

•

Thoracic aortic aneurysm is a life threatening disease.

•

It requires surgical treatment before complications arise.

•

Replacement of the arch and the descending thoracic aorta is challenging because of neurological complications.

Changes in Coronary Flow Reserve following Stent Implantation in the Swine Descending Thoracic Aorta

Purpose:

To evaluate coronary flow reserve (CFR) changes following stent implantation in the descending thoracic aorta (DTA) of a porcine model.

Methods:

Six pigs (3 males; 40 to 44 kg) were anesthetized and kept on mechanical ventilation. A 6-F guiding right Judkins catheter was advanced under fluoroscopy to the right coronary artery, and a pressure wire with a temperature sensor was placed within the vessel lumen at a distance of 4 cm from the ostium. CFR was estimated by the thermodilution method before and after maximal coronary vasodilation with 20 mg of intracoronary papaverine. Aortography was also performed to measure aortic diameter. Subsequently, a self-expanding vascular stent was deployed into the DTA just below the left subclavian artery (LSA), and CFR was measured again. All animals were maintained for 3 weeks; at the end of this period, a further CFR was calculated using the same procedure.

Results:

The mean aortic diameter below the LSA was 12.15±0.15 mm. Following stent deployment, the mean aortic diameter measured at the stented segment was 12.58±0.11 (p=0.001 versus baseline). The mean CFR value was 4.7062.00 before stent implantation, 2.6860.86 immediately after, and 4.0561.15 at 3 weeks after stenting. Accordingly, CFR values were significantly depressed immediately after stent placement compared with baseline (p=0.027). However, CFR values obtained 3 weeks following stent deployment were similar to the initial values (p=0.59).

Conclusion:

Stent deployment in the normal swine DTA produces a significant immediate decrease in CFR, which is attenuated 3 weeks later. The clinical impact of CFR changes following DTA endografting remain to be elucidated.

Endovascular repair of thoracic aortic aneurysm

A thoracic aortic aneurysm (TAA) is a potentially life-threatening condition with structural weakness of the aortic wall, which can progress to arterial dilatation and rupture. Today, both an increasing awareness of vascular disease and the access to tomographic imaging facilitate the diagnosis of TAA even in an asymptomatic stage. The risk of rupture for untreated aneurysms beyond a diameter of 5.6 cm ranges from 46% to 74% and the two-year mortality rate is greater than 70%, with most deaths resulting from rupture. Treatment options include surgical and non-surgical repair to prevent aneurysm enlargement and rupture. While most cases of ascending aortic involvement are subject to surgical repair (partially with valve-preserving techniques), aneurysm of the distal arch and descending thoracic aorta are amenable to emerging endovascular techniques as an alternative to classic open repair or to a hybrid approach (combining debranching surgery with stent grafting) in an attempt to improve outcomes.

Endovascular repair of nonruptured thoracic aortic aneurysms: systematic review

Thoracic aortic aneurysms represent a major health problem. Untreated thoracic aortic aneurysms may rupture, which has a dismal outcome. The standard treatment for thoracic aneurysms is open surgical repair, but it is associated with high mortality and morbidity. Endovascular repair provides a less invasive and safer alternative. A systematic review was performed of all published literature on the above subject. Our primary objective was to measure 30-day mortality for nonruptured thoracic aortic aneurysms. Studies describing other pathologies, such as aortic dissection, mycotic aneurysms, penetrating ulcers, traumatic transactions, and pseudoaneurysms, and studies from which independent data for thoracic aortic aneurysm could not be separately extracted were excluded. Case series describing less than 10 patients and all case series describing ruptures or concealed ruptures were excluded as well. Twenty-six case series and one comparative study were identified. This formed a cohort of 1,038 patients. Technical success was possible in more than 97% of patients. The 30-day mortality was calculated to be 5.1% even though the group under study was mostly those who were refused surgery by a surgeon or had a higher surgical risk. The incidence of paraplegia and stroke was 3.1% and 4.7%, respectively. Early endoleak was seen in 16.7% of patients, whereas 11.7% of patients developed late endoleak, but most did not require any additional procedure. The rate of reintervention was 14.9%. The 12-month mortality rate was 14.2%. Endovascular repair shows encouraging short-term results. It is associated with significantly less mortality and morbidity, but long-term results need to be further investigated.

Endovascular stent grafting versus open surgical repair of descending thoracic aortic aneurysms in low-risk patients: A multicenter comparative trial

OBJECTIVE

Results are presented from the first completed multicenter trial directed at gaining approval from the US Food and Drug Administration of endovascular versus open surgical repair of descending thoracic aortic aneurysms.

METHODS

Between September 1999 and May 2001, 140 patients with descending thoracic aneurysms were enrolled at 17 sites and evaluated for a Gore TAG Thoracic Endograft. An open surgical control cohort of 94 patients was identified by enrolling historical and concurrent subjects. Patients were assessed before treatment, at treatment, and at hospital discharge and returned for follow-up visits at 1 month, 6 months, and annually thereafter.

RESULTS

One hundred thirty-seven of 140 patients had successful implantation of the endograft. Perioperative mortality in the endograft versus open surgical control cohort was 2.1% (n = 3) versus 11.7% (n = 11, P < .001). Thirty-day analysis revealed a statistically significant lower incidence of the following complications in the endovascular cohort versus the surgical cohort: spinal cord ischemia (3% vs 14%), respiratory failure (4% vs 20%), and renal insufficiency (1% vs 13%). The endovascular group had a higher incidence of peripheral vascular complications (14% vs 4%). The mean lengths of intensive care unit stay (2.6 +/- 14.6 vs 5.2 +/- 7.2 days) and hospital stay (7.4 +/- 17.7 vs 14.4 +/- 12.8 days) were significantly shorter in the endovascular cohort. At 1 and 2 years' follow-up, the incidence of endoleaks was 6% and 9%, respectively. Through 2 years of follow-up, there were 3 reinterventions in the endograft cohort and none in the open surgical control cohort. Kaplan-Meier analysis revealed no difference in overall mortality at 2 years.

CONCLUSIONS

In this multicenter study early outcomes with descending aortic endovascular stent grafting were very encouraging when compared with those of a well-matched surgical cohort. However, at 2 years' follow-up, there is an incidence of endoleaks and reinterventions associated with endovascular versus open surgical repair. Continued vigilant surveillance of patients treated with an endograft is important.

Stent-graft versus open-surgical repair of the thoracic aorta: Mid-term results

OBJECTIVE

Pivotal and comparative trial data are emerging for stent graft (SG) vs open repair of the thoracic aorta. We reviewed procedure-related perioperative morbidity, mortality, and mid-term outcomes in a contemporary series of patients treated with SG of the thoracic aorta. The data were compared with those of a patient cohort concurrently treated with open surgical repair confined to the descending aorta.

METHODS

A review of patients undergoing SG procedures and open surgery of the thoracic aorta from January 1, 1996, to November 30, 2005, was performed from a prospectively compiled database. Study end points included perioperative complications, late survival, freedom from reinterventions, and graft-related complications. Multivariate methods were used to assess variables potentially associated with study end points; late outcomes were compared with actuarial methods.

RESULTS

In 105 patients (mean age, 70 years; 66 male [62.9%]) SG repairs were done for 68 degenerative aneurysms (64.7%), 12 penetrating ulcers (11.4%), 15 pseudoaneurysms (14.3%), 9 traumatic tears (8.6%), and 1 acute dissection (0.9%). Mean follow-up was 22 months (range, 0 to 101 months). Eighty-nine (84.8%) SG patients were asymptomatic at presentation and underwent elective repair, whereas 16 (15.2%) presented with acute conditions and underwent urgent repair. Perioperative mortality was 7.6% (8/105), and actuarial survival at 48 months was 54% +/- 7%. The perioperative mortality rate among SG patients treated for degenerative pathology was 10.4% (8/77). Seven (6.7%) of 105 patients experienced spinal cord ischemic complications, including 2 patients with transient paraparesis that resolved by the time of discharge. Reinterventions were performed in 10.5% of patients (11/105), with freedom from reintervention approaching 81% by 48 months. Over the same interval, 93 patients were treated with open-surgical repair for descending thoracic aneurysm (anastomosis cephalad to the celiac axis). Perioperative mortality in the open cohort was 15.1% (14/93; P = .09 vs SG repair), and the 48-month actuarial survival was 64% +/- 6%. The incidence of spinal cord ischemic complications was 8.6% (8/93), including 4 patients with transient paraparesis (P = .44 vs SG repair). Nine patients (9.7%) required surgical reintervention during the follow-up period, with 48-month freedom from reintervention approaching 79% (P = .73 vs SG repair).

CONCLUSIONS

Operative mortality was halved with SG, with similar late survival for both cohorts. Reinterventions were required at a nearly identical rate for open repair and SG, and both groups experienced similar rates of spinal cord ischemic complications.

Perioperative Management to Improve Neurologic Outcome in Thoracic or Thoracoabdominal Aortic Stent-Grafting

BACKGROUND

Thoracic or thoracoabdominal aortic stent-graft repair has shown a reduction in morbidity and mortality rates due to the procedure's advantages (no aortic cross-clamping, continuous distal aortic perfusion, no reperfusion injury). However, 3% to 12% of the patients are at risk of spinal cord ischemia. We investigated spinal cord protective measures with evoked potentials, cerebrospinal fluid drainage, and prevention of hypotension to minimize postoperative neurologic deficit.

METHODS

Between November 2000 and July 2005, vital parameters and spinal cord function were monitored, including cerebrospinal fluid pressure and transcranial motor-evoked and somatosensory-evoked potentials in 36 stent-graft procedures (31 patients) on the thoracic or thoracoabdominal aorta.

RESULTS

Stent-graft placement was technically successful in all patients. We achieved a survival rate of 100% without neurologic deficit after fast-track extubation. Eleven of 31 patients exhibited changes in evoked potentials during stent-graft deployment. In 12 of 31 patients (including the 11 with evoked potential alterations), cerebrospinal fluid pressure exceeded 15 mm Hg. Cerebrospinal fluid drainage and vital parameter adjustment were executed in those instances. We observed intraoperative evoked potential total recovery in 10 of 11 patients after these interventions.

CONCLUSIONS

Interventions to improve spinal cord perfusion led to total recovery of spinal function in most patients (10/11). Therefore, spinal cord protective measures with motor- and somatosensory-evoked potential monitoring, cerebrospinal fluid drainage, and prevention of hypotension can reduce the incidence of spinal cord ischemia and improve the neurologic outcome of patients undergoing endovascular thoracic or thoracoabdominal aortic repair.

Thoracic aortic stent grafting: Improving results with newer generation investigational devices

OBJECTIVE

Six years ago an endovascular program for repair of descending thoracic aneurysms was established at the University of Pennsylvania. We report on the hypothesis that results are improving with new stent design iterations and describe our experience and lessons learned.

METHODS

From April 1999 to March 2005, 99 patients with descending thoracic aneurysms underwent repair with a first or second-generation commercially produced endograft; 24 patients had an early-generation device, and 75 patients had a late-generation device. Each patient was enrolled as part of 3 distinct Phase I or Phase II Food and Drug Administration-approved clinical trials in accordance with strict inclusion and exclusion criteria.

RESULTS

Mean age was 73.1 years. Symptomatic aneurysms accounted for 42% of the cohort. Mean aneurysm size was 63.7 mm (range: 30-105 mm). Twenty percent of the patients underwent a subclavian carotid transposition or bypass preoperatively to obtain an adequate proximal landing zone. No procedures had to be aborted. In-hospital or 30-day mortality was 5.0%. The incidence of permanent spinal ischemia was 2%. Perioperative vascular complications requiring interposition graft, stent repair, or patch angioplasty occurred in 27% and seemed to be less frequent in the late-generation cohort than the early-generation cohort (22.7% vs 41.7%, respectively, P = .069). At the 30-day follow-up, 23 endoleaks were detected in 22 patients (14.7% in late-generation cohort vs 45.8% in early-generation cohort, P = .001). During the follow-up period, 3 new endoleaks were detected, 3 patients died of aortic rupture, and 10 patients underwent aneurysm-related reintervention. Kaplan-Meier estimated 1, 3, and 5-year survival was 84.5%, 70.5%, and 52.4%, respectively. Freedom from aneurysm-related event, defined as freedom from endoleak, aortic rupture, dissection, or any reintervention on the aorta, was 73%, 69%, and 64% at 1, 3, and 5 years, respectively.

CONCLUSION

Thoracic aortic stent grafting is a safe procedure in selected patients with the added benefit of a low incidence of paraplegia. However, there is an incidence of late complications and reinterventions. This risk requires further quantification and must be balanced against the benefits of a minimally invasive approach with low perioperative morbidity and mortality. Results are improving as technology evolves and our level of experience increases. Radiologic follow-up is mandatory.

The results of catheter-based therapy compared with surgical repair of adult aortic coarctation

A review was performed to compare the results of endovascular therapy (stenting and angioplasty) with surgical techniques to repair adult aortic coarctation. The immediate improvement in hypertension and the morbidity were similar across all groups. Surgical therapy was associated with a very low risk of restenosis and recurrence, whereas endovascular therapy had a much higher incidence of restenosis and the need for repeat interventions. The long-term outcome of endovascular approaches will need to be assessed in the future.

Esophageal fistula after endovascular treatment in a type B aortic dissection of the descending thoracic aorta

We report a type B aortic dissection treated with stenting of the descending thoracic aorta that subsequently developed an ischemic necrosis of the esophagus with a posterior mediastinum abscess. The surgical treatment consisted of an extra-anatomic bypass to revascularize the supra-aortic trunks and the distal abdominal aorta through a middle sternal laparotomy, the resection of the thoracic aorta, and the drainage of the mediastinal abscess. Despite this aggressive surgical approach and an initial favorable postoperative course, the patient suddenly died 3 weeks later, likely from a rupture of the aortic stump.

Current status of thoracic aortic endograft repair

The advent and success of endovascular repair of abdominal aneurysms had led to the development of catheter-based techniques to treat thoracic aortic pathology. Such diseases, including thoracic aortic aneurysms, acute and chronic type B dissections,penetrating aortic ulcers, and traumatic aortic transection, challenge surgeons to perform complex operative repairs in high-risk patients. The minimally invasive nature of thoracic endografting may provide an attractive alternative therapy especially in patients deemed unfit for thoracotomy. A worldwide review of thoracic endografting demonstrates encouraging short- and midterm outcomes with significant reductions in morbidity and early mortality.Long-term surveillance will be crucial to discover complications unique to thoracic endovascular interventions and to determine which patients are appropriate candidates for stent-graft therapy.

Endovascular Surgery and Pathology of the Thoracic Aorta

Although abdominal aortic aneurysms are the most common aortic pathology in the general population, the thoracic aorta is also a frequent site of aneurysms, chronic dissections, transections, and other potentially life-threatening pathologies. Not all of these lesions are amenable to endovascular repair; however, early evidence suggests that endovascular intervention in selected patients has a high rate of acute and midterm success. Indeed, the endovascular procedure reduces operating time and the need for blood transfusions and usually results in shorter intensive care unit and hospital stays compared with open surgery. In addition, overall rehabilitation is comparatively brief. Although these results are encouraging, no outcome data from randomized trials exists, and further study of the long-term efficacy and safety of endoluminal grafting is warranted.