Midterm results of stent-graft repair of acute and chronic aortic dissection with descending tear: the complication-specific approach

Degree of fusiform dilatation of the proximal descending aorta in type B acute aortic dissection can predict late aortic events

OBJECTIVE

Predicting the risk factors for late aortic events in patients with type B acute aortic dissection without complications may help to determine a therapeutic strategy for this disorder. We investigated whether late aortic events in type B acute aortic dissection can be predicted accurately by an index that expresses the degree of fusiform dilatation of the proximal descending aorta during the acute phase; this index can be calculated as follows: (maximum diameter of the proximal descending aorta)/(diameter of the distal aortic arch + diameter of the descending aorta at the pulmonary artery level).

METHODS

Patients with type B acute aortic dissection without complications (n = 141) were retrospectively analyzed to determine the predictors of late aortic events; these include aortic dilatation, rupture, refractory pain, organ ischemia, rapid aortic enlargement, and rapid enlargement of ulcer-like projections.

RESULTS

The fusiform index in patients with late aortic events (0.59) was higher than that in patients without late aortic events (0.53, P < .01). Patients with a higher fusiform index exhibited aortic dilatation earlier than those with a lower fusiform index. By multivariate analysis, we conclude that the predominant independent predictors of late aortic events were a maximum aortic diameter of 40 mm or more, a patent false lumen, and a fusiform index of 0.64 or more (hazard ratios, 3.18, 2.64, and 2.73, respectively). The values of actuarial freedom from aortic events for patients with all 3 predictors at 1, 5, and 10 years were 22%, 17%, and 8%, respectively, whereas the values in those without these predictors were 97%, 94%, and 90%, respectively.

CONCLUSIONS

The degree of fusiform dilatation of the proximal descending aorta, a patent false lumen, and a large aortic diameter can be predominant predictors of late aortic events in patients with type B acute aortic dissection. Patients with these predictors should be recommended to undergo early interventions (surgery or stent-graft implantation) or at least be closely followed up during the chronic phase before such events develop.

Thoracic aortic stent-graft devices: problems, failure modes, and applicability

Optimal treatment strategies for pathologies of the descending thoracic aorta are still controversial. Open surgery is complex, while endovascular devices allow nonsurgical access to the thoracic aorta. Endografts can be inserted via a peripheral artery while maintaining aortic blood flow without any need for clamping. Both short- and mid-term outcomes after endografting thoracic aneurysm and type B aortic dissection are encouraging, with significantly lower morbidity and early mortality compared with open surgery. However, despite emerging popularity and growing interest as an alternative to surgery, endograft design and manufacturing have not kept pace with growing clinical ambition. Major challenges associated with endovascular procedures using the current generation of endografts range from the relative rigidity and size of the delivery system to the failure of thoracic endografts to conform snugly to the anatomy of the aortic arch. Nonconformity of grafts may lead to graft instability, endoleak, and procedural failure. Current delivery systems are potentially traumatizing and, at times, too inflexible to track through tortuous, calcified vessels, and often require surgical exposure of the access vessel. Although efforts have been made by the industry to improve conformability and fixation in the aortic arch, given the spiraling movement of the thoracic aorta with each ventricular contraction, much work needs to be done on miniaturization and creation of disease-specific devices. The aim of this work is to give an overview on thoracic aortic stent-graft devices with focus on problems, failure modes and potential improvements.

Effectiveness of intensive medical therapy in type B aortic dissection: A single-center experience

OBJECTIVE

Although the mainstay of managing acute descending thoracic aortic dissection (ADTAD) remains medical, certain patients will require emergency surgery for complications of rupture or ischemia. This study evaluates factors that affect outcome and determines which patients previously treated surgically would have been eligible for endovascular repair.

METHODS

A single-institution retrospective study was conducted of patients who presented with clinical signs of ADTAD that was confirmed by magnetic resonance angiography (MRA) or computed tomography (CT). All patients were admitted to the intensive care unit (ICU) and medically managed to maintain systolic blood pressure<120 mm Hg and heart rate<70 beats/min. Two treatment groups were identified: group 1 received medical treatment only; group 2 received medical treatment plus emergency surgery. Patient demographic and clinical data were correlated with 30-day group mortality and morbidity and need for emergency surgery. The MRA and CT scan images of group 2 were retrospectively reviewed to determine if currently available endovascular treatment could have been done. The Fisher exact test was used to compare between the groups, and P<.05 was considered significant.

RESULTS

Between 1991 and 2005, 83 patients (55 men) were treated for ADTAD. The mean age was 67 years (range, 38 to 85). Sixty-eight patients (82%) had hypertension, three (3.6%) had Marfan syndrome, and 51 (62%) were smokers. Twenty-five (32%) of the patients were receiving beta-blocker therapy before the onset of their symptoms. Back pain was the most common initial symptom (72.2%). Emergency surgery was required in 19 patients (23%): 12 for rupture or impending rupture, four for mesenteric ischemia, and three for lower extremity ischemia. The need for emergency surgery was significantly higher in smokers (P=.03), in patients>70 years old (P=.035), and in patients who were not receiving beta-blocker therapy before the onset of symptoms (P=.023). The combined overall morbidity rate was 33%, and the mortality rate was 9.6%. Morbidity in group 2 was 64% and significantly higher than the 23% in group 1 (P=.00227). The mortality rate was also higher in group 2 at 31.5% compared with group 1 at 1.6% (P=.0004). Factors affecting the overall mortality included age>70 years (P=.057), previous abdominal aortic aneurysm repair (P=.018), tobacco use (P=.039), and the presence of leg pain at initial presentation (P=.013). As determined from the review of radiologic data, 11 of 13 patients with scans available for review in group 2 could have been treated with currently available endovascular grafts.

CONCLUSIONS

Intensive medical therapies are effective in preventing early mortality associated with ADTAD. Predictably, the need for emergency surgery carries a high morbidity and mortality rate. Most patients in this series requiring emergency surgery could have been candidates for endovascular therapy had it been available.

Endovascular Repair of Acute Type B Aortic Dissection: Long-Term Follow-Up of True and False Lumen Diameter Changes

BACKGROUND

The aim of this study was to determine the technical success after endovascular treatment of acute type B aortic dissections and to evaluate true and false lumen diameter changes at long-term follow-up.

METHODS

Twenty-eight patients with acute type B-dissection who were treated by stent graft repair presented with rupture (n = 1), contained rupture (n = 2), compromised branch vessels (n = 14), pleural effusion (n = 11), rapid aortic diameter progression (n = 5), persistent pain (n = 3), refractory hypertension (n = 10), and an aortic diameter of more than 4 cm (n = 4). Taking into account the perfusion status of the false lumen, diameter changes were monitored in the thoracic aorta at the level of the stented segment (L1), distal to the stent graft (L2), and at the level of the celiac trunk (L3).

RESULTS

Severe complications in 9 patients (32%) resulted in 3 deaths for a 30-day mortality rate of 10.7%. Primary sealing of the entry tear was achieved in 86%. At all levels, the true lumen diameter increased significantly after stent graft placement. At the 1-year follow-up, the false lumen in L1 was thrombosed in 90% and the mean difference of diameter reduction was highly significant. In L2, complete false lumen thrombosis occurred in 60% with a significant diameter decrease. In L3, the false lumen thrombosed in only 22%, and the mean difference of false lumen diameter increase reached significance at the 2-year follow-up.

CONCLUSIONS

Ninety percent of patients were treated successfully with thrombosis of the false lumen in the stented segment. False lumen perfusion distal to the stent graft resulted in diameter increase in several patients leaving these segments an area of concern.

Emergency endovascular stent-graft treatment for acute thoracic aortic syndromes

OBJECTIVE

We report the results of our ongoing experience of urgent and emergency stent-graft implantation in acute thoracic aortic syndromes.

METHODS AND RESULTS

In the last 5-years, 19 patients were treated for acute thoracic aortic syndromes. Traumatic rupture was diagnosed in 7 patients, complicated acute type B dissection was present in 5 patients, penetrating ulcer in 4, and symptomatic thoracic aortic aneurysm in 3 patients. There were 17 male patients with a mean age of 54 +/-26 years (range 18-87 ; median 63). Patients were treated in the theatre suite under general anesthesia. Stent-graft placement was technically successful in all patients. The early postoperative mortality was 10.5 %. Neurological events or upper arm ischemia due to overstenting of the left subclavian artery were not observed. Average intensive care unit and hospital stay were 18 and 21 days, respectively. Major complications occurred in 6 patients. Follow-up ranged between 3 and 60 months (mean 25) and included clinical examinations and serial CT-angiography at 1, 4 and 12 months, and every year thereafter. Only one type II endoleak was detected and treated by coil embolization of the left subclavian artery.

CONCLUSIONS

Our experience suggests emergency stent-graft repair in patients with acute thoracic aortic syndromes is a less-invasive attractive alternative, showing encouraging early and mid-term results.

Will Stent-Graft Repair Emerge as Treatment of Choice for Acute Type B Dissection?

Endovascular stent grafts are now accepted globally and approved by the US Food and Drug Administration as an alternative to open surgical repair for patients with descending thoracic aortic aneurysm. However, as opposed to the abdominal aorta, application of this technology to manage thoracic aortic disease is not limited to degenerative aneurysms. In fact, international registries and surveys estimate that only 60% of the thoracic cases managed currently with stent-graft placement are aneurysms. The remainder of this experience includes acute dissection, chronic dissection, traumatic aortic injury, penetrating ulcer, intramural hematoma, aortic fistula, anastomotic pseudoaneurysm, and an embolizing lesion. In this regard, it is important to keep in mind that the present devices used in these nonaneurysmal applications are not designed to address the unique anatomical and pathological features that these lesions present. Consequently, in the future, it is possible that we will see stent-graft designs that focus specifically on the challenges of some of the nonaneurysmal thoracic aortic pathologies.

Problems Encountered during and after Stent-Graft Treatment of Aortic Dissection

PURPOSE

The authors report their experiences with the problems encountered during and after stent-graft placement in patients with aortic dissections.

MATERIALS AND METHODS

Between July 1994 and December 2003, stent-graft placement was performed in 60 patients with aortic dissections, 9 patients with Stanford type A dissection and 51 patients with type B. Ten patients had acute dissection and 50 patients had chronic dissection. Each patient was followed for 12 to 107 months (mean, 33 mo). All cases were retrospectively reviewed for any problem that occurred during and after the procedure.

RESULTS

During the procedure, there were two cases (3%) of stent-graft migration, one case (2%) of stent-graft torsion, two cases (3%) of stent-graft folding due to oversizing, three cases (5%) of persistent thoracic false lumen flow by the appearance of a hidden intimal tear, one case (2%) of new intimal tear that resulted in retrograde type A dissection, and 12 cases (20%) of type I endoleaks on aortograms taken immediately after the procedure. During the follow-up period, one case (2%) of transient cerebral ischemia, six cases (10%) of persistent type I endoleaks, two cases (3%) of type II endoleaks through the intercostal artery, four cases (7%) with progressive dilatation of abdominal false lumen, six cases (10%) of new intimal tears which resulted in saccular aneurysms (n=4) or new dissections (n=2) on either or both ends of the stent-graft, and two cases (3%) of mechanical failure were observed. Overall, five patients (8%) required surgical conversion, and there were no cases of procedure-related mortality.

CONCLUSION

Various problems can occur during and after stent-graft placement in aortic dissection. The thorough evaluation of preoperative imaging and close follow-up are mandatory to optimize the management of such problems.

Endovascular stent-graft placement in aortic dissection: a meta-analysis

AIMS

This article summarizes all available published data with respect to clinical success, complications, and outcomes of endovascular stent-graft placement among patients with descending aortic dissection (AD).

METHODS AND RESULTS

We performed a meta-analysis of all published series on retrograde endovascular stent-graft placement encompassing >or=3 patients with AD. Thirty-nine studies, involving a total of 609 patients, were included. Procedural success was reported in 98.2+/-0.5% of patients. Major complications were reported in 11.1+/-1.4%, with the most dreaded neurologic complications in 2.9+/-0.7% patients. Periprocedural stroke was encountered more frequently than paraplegia (1.9+/-0.6% vs. 0.8+/-0.4%). Overall complications were significantly higher in patients undergoing stent-graft placement for acute AD than in patients with chronic AD (21.7+/-2.8% vs. 9.1+/-2.3%, P=0.005). The overall 30-day mortality was 5.3+/-0.9%, and was three-fold higher in patients with acute AD when compared with chronic AD (9.8+/-2.2% vs. 3.2+/-1.4%, P=0.015). In addition, 2.8+/-0.7% of patients died over a mean follow-up period of 19.5+/-7.1 months. Kaplan-Meier analysis yielded overall survival rates of 90.6+/-1.6% at 6 months, 89.9+/-1.7% at 1 year, and 88.8+/-1.9% at 2 years, respectively.

CONCLUSION

Endovascular stent-graft placement in type B-AD is technically feasible with success rates of >95% in selected cohort. Although minimally invasive, major complications occurred in 14-18% of patients depending upon the acuity of presentation, with very low incidence of paraplegia. Both, acute and mid-term mortality of this novel treatment strategy appear to favourably compare with surgical treatment but further studies are necessary to compare stent-graft placement with medical treatment in uncomplicated AD.

Endovascular repair of the descending thoracic aorta: evidence for the change in clinical practice

The purpose was to review outcome data following endovascular repair of the descending thoracic aorta from reports published between 1994 and 2004. To accomplish this task, 1,518 patients underwent endovascular repair for thoracic aortic disease; 810 thoracic aortic aneurysms, 500 type B thoracic aortic dissections, and 106 traumatic ruptures. The 30-day mortality rate was 5.5% and 6% for late postoperative deaths. The primary technical success rate was 97%, with only 15 patients requiring open conversion. Neurologic deficits occurred in 29 patients. In total, 118 endoleaks were reported; 29 were restented, and the remainder required surgical intervention. Graft infection occurred in 6 cases, and migrations were detected in 10. The conclusion reached is that endovascular repair of descending thoracic aortic disease is feasible and can be achieved with low rates of perioperative morbidity and mortality. As few long-term data exist on the durability of thoracic stent grafts, lifelong surveillance remains necessary.

Extension of dissection in stent-graft treatment of type B aortic dissection: lessons learned from endovascular experience

Endovascular treatment is becoming the most important treatment modality in the complex management of type B dissection, providing benefits to both acute and chronic patients. Growing technical experience and improving stent-graft devices have resulted in better patient outcome and expanded clinical indications. Nevertheless, similar to any treatment option, this less invasive method has its inherent risks. Several cases of iatrogenic dissection have been reported in the literature, underlying the need for guidelines to minimize this risk and improve procedural safety. Extension of the dissection after endovascular repair of type B dissection does not appear to be device-specific, but related primarily to aortic wall alterations or adverse anatomy that arise most frequently in hypertensive patients or those with challenging aortic configuration. An accurate examination of the aortic wall and dissection anatomy and careful intraprocedural device manipulation and balloon molding may help avoid this potentially life-threatening complication.

Endografting of the aortic arch

In recent years, endovascular repair with stent-grafts has made great advances as a minimally invasive alternative to conventional open surgery in the treatment of aortic aneurysm and dissection. Although many commercial endograft systems are now used worldwide for the treatment of these pathologies in the abdominal aorta, only a few dedicated stent-grafts have been developed for use in the thoracic aorta. However, these second-generation commercial endografts have almost identical specifications and performance profiles in terms of structure, function, and delivery mechanism as stent-graft systems employed in the abdominal aorta. Thus, endografts have been used in the thoracic aorta with little consideration to the morphological and hemodynamic characteristics specific to the aortic arch and the deployment techniques needed to navigate this curved region of the thoracic aorta. This review will survey the literature on aortic arch stent-graft repair and identify key elements critical to the successful design of an endograft to treat lesions in the aortic arch.

Endovascular stent-graft treatment of aortic dissection: determinants of post-interventional outcome

AIMS

To investigate the results of endovascular stent-graft placement for the treatment of patients with type B aortic dissection (B-AD).

METHODS AND RESULTS

A total of 38 patients (62+/-10 years, 32 male) with acute (n=10) and chronic (n=28) type B-AD were treated with endovascular stent-grafts. The implantation procedure was successful in all patients. Peri-procedural non-fatal complications occurred in four (11%) patients. Overall, 4/38 (11%) patients died during the in-hospital period. Patients undergoing stent-graft placement for acute AD had a significantly higher in-hospital mortality than patients with chronic AD (40 vs. 0%, P=0.001). During a median follow-up of 18 (1-57) months, there were six additional deaths. Overall survival rates were 97.4+/-2.6% at 30 days, 80.4+/-6.7% at 1 year, 73.2+/-7.8% at 2 years, and 54.9+/-16.9% at 4 years. Patients with a poor clinical health status (ASA class > 3) had a significantly reduced life expectancy compared with patients with only moderate co-morbidities (ASA class </= 3) (1-year survival rate 28.6+/-17.1 vs. 92.6+/-6.7%, P=0.0001). Multivariable analysis revealed that a poor clinical health status (ASA>3) pre-operatively (HR=29.5, 95% CI 1.5-581.9, P=0.026) and increased age (HR=1.1, 95% CI 0.9-1.2, P=0.084) were independent determinants of post-interventional mortality.

CONCLUSION

Endovascular stent-graft treatment is a safe alternative for patients with AD. The pre-operative clinical health status of the patient is the most important determinant of post-interventional outcome. Careful patient selection is thus of particular importance.

Comparison of a percutaneous separate stent endograft and a conventional thoracic stent-graft for endovascular repair of type B aortic dissection

PURPOSE

To compare the immediate and midterm outcomes of aortic dissection repair with a separate stent endograft (SSE) versus a conventionally constructed thoracic stent-graft.

METHODS

The records of 35 patients treated for type B aortic dissection from September 1997 to April 2003 were reviewed. Seventeen patients (12 men; mean age 58.8+/-11.6 years) underwent endovascular repair with a separate stent endograft (SSE), a custom-made device with a reduced profile suitable for percutaneous introduction through a 12-F sheath. Eighteen patients (10 men; mean age 56.1+/-12.8 years) underwent treatment with a conventional custom-made stent-graft.

RESULTS

Angiographic success was achieved in 13/17 (76.5%) of the SSE-treated patients and 12/18 (66.7%) for the conventional device group (p=0.521). Clinical success (complete obliteration/thrombosis of the false lumen) was achieved in 12/17 (70.6%) and 11/18 (61.1%), respectively (p=0.555). There were 2 cases of stent-graft movement during deployment and 2 access site complications in the conventional stent-graft group, whereas the SSE patients had no complications. Except for 2 conventional stent-graft patients who were lost to follow-up, all patients are alive at a mean 19.5+/-11.6 months for the SSE group and 34.2+/-21.5 months for the conventional stent-graft patients.

CONCLUSIONS

The separate stent endograft can be deployed percutaneously without the need for blood pressure reduction, achieving accurate deployment without migration. In this small clinical experience, patients treated with the SSE had no access site complications and demonstrated midterm results comparable to the conventional stent-graft cohort, suggesting the possible usefulness of this device for the treatment of thoracic aortic dissection.

Transesophageal echocardiography–guided algorithm for stent-graft implantation in aortic dissection

OBJECTIVE

Endovascular stent-graft placement is replacing traditional surgery in type B aortic dissection. Usually stent-graft implantation is performed under fluoroscopic and angiographic guidance, but this relatively new procedure is still burdened with some complications. We investigated the value of a developed algorithm based on transesophageal echocardiography (TEE) for guiding stent-graft implantation in type B aortic dissection.

METHODS

Forty-two patients with type B aortic dissection (chronic in 28 patients with aneurysmal dilatation of the false lumen, and acute complicated in 14 patients) underwent endovascular stent-graft reconstruction of the descending thoracic aorta. TEE was always performed after angiography. TEE-induced variations of the procedure, based on the algorithm, were compared with initial angiography-based decisions.

RESULTS

TEE was decisive for guidewire repositioning (not possible with fluoroscopy) from the false to the true lumen in 3 patients and for correct guidewire entrance in an elephant trunk prosthesis in another patient. After stent-graft implantation color Doppler TEE enabled detection of proximal peri-stent leaks in 13 patients, whereas only 6 (46%) of the 13 leaks were detectable at angiography (P = .008). Most leaks were subsequently eliminated with balloon dilation or further stent grafting. Pulsed Doppler TEE was also useful for differentiating true leaks (13 patients) from Dacron porosity (7 patients). A pulsed-Doppler velocity cutoff value of 50 cm/s enabled differentiation of Dacron porosity (characterized by slow blood flow) from true peri-stent leak (fast flow). After stent-graft implantation TEE demonstrated new intimal tears in the thoracic aorta in 7 patients, whereas only 2 of the 7 new tears were detectable at angiography (P = .024); in 6 of 7 patients the new distal tears were subsequently resolved with placement of additional stents, whereas in a patient with Marfan syndrome new proximal tears determined a type I endoleak, which could not be resolved. Overall, TEE furnished decisive information additional to angiography in determining successful procedural changes in 16 of 42 patients (38%). There were no in-hospital deaths, and pre-discharge spiral computed tomograms showed a good outcome of stent-graft implantation in 37 of 42 patients (88%), with 5 residual type I endoleaks, all previously detected with TEE but impossible to eliminate with either balloon molding or further stent implantation. All but 2 patients (95%) are currently alive at mean follow-up of 30 +/- 18 months.

CONCLUSIONS

TEE algorithm is an easy and useful tool in the operating room to guide correct stent-graft positioning in type B aortic dissection.

Twenty-year experience with acute distal thoracic aortic dissections

BACKGROUND

There are few large studies in the literature that document the clinical outcome of an acute dissection of the distal thoracic aorta (ADDA), particularly since the advent of percutaneous techniques for therapeutic and prophylactic treatment of complications of ADDA. The goal of this study was to evaluate the outcome of ADDA with respect to medical, surgical, and percutaneous treatment over a 20-year period, and to use this information to estimate the benefit that future prophylactic therapy may yield.

METHODS

The hospital records of all patients admitted with ADDA during the period of the study were reviewed retrospectively.

RESULTS

There were 119 patients who fit the criteria of ADDA. Medical management was performed in 92 patients, with an overall mortality in this group of 13% (12/92 patients). Major morbidity occurred in 34 of the 83 surviving patients managed nonoperatively. Percutaneous interventions consisting of aortic fenestration and branch vessel stenting in 5 patients had a mortality rate of 40% and was only effective in the treatment of isolated renal artery malperfusion. Twenty-two patients underwent aortic surgery for complications or risk of impending rupture. Postoperative mortality was 18% (4/22 patients). Significant risk factors for death were rupture, acute renal failure, mesenteric ischemia, and age >70. No patient who had surgical fenestration required reoperation on the tailored segment. On the basis of clinical outcomes, we estimate that a maximum of 37% of patients could benefit acutely from prophylactic treatment of ADDA with aortic stent grafts, and an additional 13% could benefit chronically from such prophylactic treatment.

CONCLUSIONS

ADDA remains a challenging clinical problem with many failures of medical, surgical, and percutaneous therapy. Surgery remains an effective therapeutic option in the treatment of complications of acute dissection of the distal thoracic aorta, and surgical aortic fenestration is a durable treatment for malperfusion. A minority of patients may benefit from prophylactic treatment of ADDA with thoracic stent grafts.

Aortic Dissections: New Perspectives and Treatment Paradigms

Aortic dissection is a complex manifestation of disease of the arterial wall. The severity and consequences of a dissection are related to the physical characteristics and anatomic location of the tear as well as the underlying patient physiology. Despite in vitro and in vivo modeling advances, our understanding of the pathophysiology has been limited to evaluations of the success and failure of various treatment modalities. The indications for intervention have historically included rupture, intractable pain or hypertension, distal ischemia and degeneration of the aortic wall causing aneurysm formation. The management decisions for patients with dissections are dependent upon the abnormal anatomy, the acuity of the patient presentation, and physiology. Despite the availability of open surgery as a therapeutic option, acute dissections with evidence of ischemia are now handled using an endovascular approach that is specifically directed at the cause of the ischemia. Endovascular treatments include the placement of a stentgraft into the proximal aorta, branch vessel stenting, uncovered stent placement in the abdominal aorta, and aortic fenestrations. Chronic dissections, in contrast, are still most frequently managed with open surgical techniques. However, a subset of patients that are not candidates for traditional surgical repair of the thoracoabdominal aorta may be managed with a combined open mesenteric revascularization with subsequent endovascular grafting of the thoracoabdominal aorta.