Aortic Dissections: New Perspectives and Treatment Paradigms

Revascularization-first strategy versus central repair-first strategy for acute type A aortic dissection complicated with mesenteric malperfusion syndrome: A meta-analysis

OBJECTIVE

The optimal therapeutic strategy for acute type A aortic dissection (ATAAD) accompanied by mesenteric malperfusion syndrome (mMPS) has not been fully elucidated. The intent of this meta-analysis was to analyze the effectiveness and safety of the revascularization-first strategy among patients with ATAAD complicated with mMPS through comprehensive comparisons with the central repair-first strategy.

METHODS

Studies relevant to the comparison of the outcomes of early reperfusion combined with delayed proximal aortic repair and initial central repair in the treatment of ATAAD complicated with mMPS, were systematacially searched using PubMed, Cochrane Library, Web of Science and Embase up to June 30, 2022. And the primary outcome was early mortality, with mesenteric complications, adverse aortic events and hypothermic circulatory arrest (HCA) time served as the secondary outcomes. Screening of the relevant studies, data extraction, and assessment of the included studies were conducted by two authors independently. Standard statistical procedures provided in Review Manager 5.3 were used to perform all statistical analyses.

RESULTS

Five studies comprising 72 patients in total were included into the quantitative synthesis. In-hospital/30-day mortality was significantly reduced in patients receiving the revascularization-first strategy than in those with the central repair-first strategy, with a pooled risk ratio (RR) of 0.46 (p = .04, 95% confidence interval [CI]: 0.22-0.95). The revascularization-first strategy resulted in a lower incidence of mesenteric complications compared with the central repair-first strategy, with a pooled RR of 0.15 (p = .0002, 95% CI: 0.05-0.41). Moreover, no significant difference was found in the comparison of the revascularization-first strategy and central repair-first strategy regarding adverse aortic events (p = .31, 95% CI: 0.44-12.78). Compared with central repair-first, a longer HCA time was observed in revascularization-first with mean difference of 9.91 (p = .02, 95% CI: 1.34-18.48).

CONCLUSIONS

The revascularization-first strategy presented a lower in-hospital/30-day mortality and mesenteric complications than the central repair-first strategy without increasing the incidence of adverse aortic events. However, the revascularization-first strategy indicated a longer HCA time than the central repair-first strategy.

MRI in CFD for chronic type B aortic dissection: Ready for prime time?

OBJECTIVES

Better tools are needed for risk assessment of Type B aortic dissection (TBAD) to determine optimal treatment for patients with uncomplicated disease. Magnetic resonance imaging (MRI) has the potential to inform computational fluid dynamics (CFD) simulations for TBAD by providing individualised quantification of haemodynamic parameters, for assessment of complication risks. This systematic review aims to present an overview of MRI applications for CFD studies of TBAD.

METHODS

Following PRISMA guidelines, a search in Medline, Embase, and the Scopus Library identified 136 potentially relevant articles. Studies were included if they used MRI to inform CFD simulation in TBAD.

RESULTS

There were 20 articles meeting the inclusion criteria. 19 studies used phase contrast MRI (PC-MRI) to provide data for CFD flow boundary conditions. In 12 studies, CFD haemodynamic parameter results were validated against PC-MRI. In eight studies, geometric models were developed from MR angiography. In three studies, aortic wall or intimal flap motion data were derived from PC/cine MRI.

CONCLUSIONS

MRI provides complementary patient-specific information in CFD haemodynamic studies for TBAD that can be used for personalised care. MRI provides structural, dynamic and flow data to inform CFD for pre-treatment planning, potentially advancing its integration into clinical decision-making. The use of MRI to inform CFD in TBAD surgical planning is promising, however further validation and larger cohort studies are required.

Beyond Atherosclerosis and Fibromuscular Dysplasia: Rare Causes of Renovascular Hypertension

Renovascular hypertension is one of the most common forms of secondary hypertension. Over 95% of cases of renovascular hypertension are due either to atherosclerosis of the main renal artery trunks or to fibromuscular dysplasia. These two causes of renal artery stenosis have been extensively discussed in recent reviews and consensus. The aim of the current article is to provide comprehensive and up-to-date information on the remaining causes. While these causes are rare or extremely rare, etiologic and differential diagnosis matters both for prognosis and management. Therefore, the clinician cannot ignore them. For didactic reasons, we have grouped these different entities into stenotic lesions (neurofibromatosis type 1 and other rare syndromes, dissection, arteritis, and segmental arterial mediolysis) often associated with aortic coarctation and other arterial abnormalities, and nonstenotic lesions, where hypertension is secondary to compression of adjacent arteries and changes in arterial pulsatility (aneurysm) or to the formation of a shunt, leading to kidney ischemia (arteriovenous fistula). Finally, thrombotic disorders of the renal artery may also be responsible for renovascular hypertension. Although thrombotic/embolic lesions do not represent primary vessel wall disease, they are characterized by frequent macrovascular involvement. In this review, we illustrate the most characteristic aspects of these different entities responsible for renovascular hypertension and discuss their prevalence, pathophysiology, clinical presentation, management, and prognosis.

Beyond Atherosclerosis and Fibromuscular Dysplasia: Rare Causes of Renovascular Hypertension

Renovascular hypertension is one of the most common forms of secondary hypertension. Over 95% of cases of renovascular hypertension are due either to atherosclerosis of the main renal artery trunks or to fibromuscular dysplasia. These two causes of renal artery stenosis have been extensively discussed in recent reviews and consensus. The aim of the current article is to provide comprehensive and up-to-date information on the remaining causes. While these causes are rare or extremely rare, etiologic and differential diagnosis matters both for prognosis and management. Therefore, the clinician cannot ignore them. For didactic reasons, we have grouped these different entities into stenotic lesions (neurofibromatosis type 1 and other rare syndromes, dissection, arteritis, and segmental arterial mediolysis) often associated with aortic coarctation and other arterial abnormalities, and nonstenotic lesions, where hypertension is secondary to compression of adjacent arteries and changes in arterial pulsatility (aneurysm) or to the formation of a shunt, leading to kidney ischemia (arteriovenous fistula). Finally, thrombotic disorders of the renal artery may also be responsible for renovascular hypertension. Although thrombotic/embolic lesions do not represent primary vessel wall disease, they are characterized by frequent macrovascular involvement. In this review, we illustrate the most characteristic aspects of these different entities responsible for renovascular hypertension and discuss their prevalence, pathophysiology, clinical presentation, management, and prognosis.

Beyond Atherosclerosis and Fibromuscular Dysplasia: Rare Causes of Renovascular Hypertension

Renovascular hypertension is one of the most common forms of secondary hypertension. Over 95% of cases of renovascular hypertension are due either to atherosclerosis of the main renal artery trunks or to fibromuscular dysplasia. These two causes of renal artery stenosis have been extensively discussed in recent reviews and consensus. The aim of the current article is to provide comprehensive and up-to-date information on the remaining causes. While these causes are rare or extremely rare, etiologic and differential diagnosis matters both for prognosis and management. Therefore, the clinician cannot ignore them. For didactic reasons, we have grouped these different entities into stenotic lesions (neurofibromatosis type 1 and other rare syndromes, dissection, arteritis, and segmental arterial mediolysis) often associated with aortic coarctation and other arterial abnormalities, and nonstenotic lesions, where hypertension is secondary to compression of adjacent arteries and changes in arterial pulsatility (aneurysm) or to the formation of a shunt, leading to kidney ischemia (arteriovenous fistula). Finally, thrombotic disorders of the renal artery may also be responsible for renovascular hypertension. Although thrombotic/embolic lesions do not represent primary vessel wall disease, they are characterized by frequent macrovascular involvement. In this review, we illustrate the most characteristic aspects of these different entities responsible for renovascular hypertension and discuss their prevalence, pathophysiology, clinical presentation, management, and prognosis.

Beyond Atherosclerosis and Fibromuscular Dysplasia: Rare Causes of Renovascular Hypertension

Renovascular hypertension is one of the most common forms of secondary hypertension. Over 95% of cases of renovascular hypertension are due either to atherosclerosis of the main renal artery trunks or to fibromuscular dysplasia. These two causes of renal artery stenosis have been extensively discussed in recent reviews and consensus. The aim of the current article is to provide comprehensive and up-to-date information on the remaining causes. While these causes are rare or extremely rare, etiologic and differential diagnosis matters both for prognosis and management. Therefore, the clinician cannot ignore them. For didactic reasons, we have grouped these different entities into stenotic lesions (neurofibromatosis type 1 and other rare syndromes, dissection, arteritis, and segmental arterial mediolysis) often associated with aortic coarctation and other arterial abnormalities, and nonstenotic lesions, where hypertension is secondary to compression of adjacent arteries and changes in arterial pulsatility (aneurysm) or to the formation of a shunt, leading to kidney ischemia (arteriovenous fistula). Finally, thrombotic disorders of the renal artery may also be responsible for renovascular hypertension. Although thrombotic/embolic lesions do not represent primary vessel wall disease, they are characterized by frequent macrovascular involvement. In this review, we illustrate the most characteristic aspects of these different entities responsible for renovascular hypertension and discuss their prevalence, pathophysiology, clinical presentation, management, and prognosis.

Mid-Term Results of Thoracic Endovascular Aortic Repair for Complicated Acute Type B Aortic Dissection at a Single Center

Background

Complicated acute type B aortic dissection is a life-threatening condition with high morbidity and mortality. The aim of this study was to report a single-center experience with endovascular stent-graft repair of acute type B dissection of the thoracic aorta and to evaluate the mid-term outcomes.

Methods

We reviewed 18 patients treated for complicated acute type B aortic dissection by thoracic endovascular aortic repair (TEVAR) from September 2011 to July 2017. The indications for surgery included rupture, impending rupture, limb ischemia, visceral malperfusion, and paraplegia. The median follow-up was 34.50 months (range, 12–80 months).

Results

The median interval from aortic dissection to TEVAR was 5.50 days (range, 0–32 days). There was no in-hospital mortality. All cases of malperfusion improved except for 1 patient. The morbidities included endoleak in 2 patients (11.1%), stroke in 3 patients (16.7%), pneumonia in 2 patients (11.1%), transient ischemia of the left arm in 1 patient (5.6%), and temporary visceral ischemia in 1 patient (5.6%). Postoperative computed tomography angiography at 1 year showed complete thrombosis of the false lumen in 15 patients (83.3%).

Conclusion

TEVAR of complicated type B aortic dissection with a stent-graft was effective, with a low morbidity and mortality rate.

Biomechanical Material Characterization of Stanford Type-B Dissected Porcine Aortas

Aortic dissection (AD) involves tearing of the medial layer, creating a blood-filled channel called false lumen (FL). To treat dissections, clinicians are using endovascular therapy using stent grafts to seal the FL. This procedure has been successful in reducing mortality but has failed in completely re-attaching the torn intimal layer. The use of computational analysis can predict the radial forces needed to devise stents that can treat ADs. To quantify the hyperelastic material behavior for therapy development, we harvested FL wall, true lumen (TL) wall, and intimal flap from the middle and distal part of five dissected aortas. Planar biaxial testing using multiple stretch protocols were conducted on tissue samples to quantify their deformation behavior. A novel non-linear regression model was used to fit data against Holzapfel–Gasser–Ogden hyperelastic strain energy function. The fitting analysis correlated the behavior of the FL and TL walls and the intimal flap to the stiffness observed during tensile loading. It was hypothesized that there is a variability in the stresses generated during loading among tissue specimens derived from different regions of the dissected aorta and hence, one should use region-specific material models when simulating type-B AD. From the data on material behavior analysis, the variability in the tissue specimens harvested from pigs was tabulated using stress and coefficient of variation (CV). The material response curves also compared the changes in compliance observed in the FL wall, TL wall, and intimal flap for middle and distal regions of the dissection. It was observed that for small stretch ratios, all the tissue specimens behaved isotropically with overlapping stress–stretch curves in both circumferential and axial directions. As the stretch ratios increased, we observed that most tissue specimens displayed different structural behaviors in axial and circumferential directions. This observation was very apparent in tissue specimens from mid FL region, less apparent in mid TL, distal FL, and distal flap tissues and least noticeable in tissue specimens harvested from mid flap. Lastly, using mixed model ANOVAS, it was concluded that there were significant differences between mid and distal regions along axial direction which were absent in the circumferential direction.

Role of Pulse Pressure and Geometry of Primary Entry Tear in Acute Type B Dissection Propagation

The hemodynamic and geometric factors leading to propagation of acute Type B dissections are poorly understood. The objective is to elucidate whether geometric and hemodynamic parameters increase the predilection for aortic dissection propagation. A pulse duplicator set-up was used on porcine aorta with a single entry tear. Mean pressures of 100 and 180 mmHg were used, with pulse pressures ranging from 40 to 200 mmHg. The propagation for varying geometric conditions (%circumference of the entry tear: 15–65%, axial length: 0.5–3.2 cm) were tested for two flap thicknesses (1/3rd and 2/3rd of the thickness of vessel wall, respectively). To assess the effect of pulse and mean pressure on flap dynamics, the %true lumen (TL) cross-sectional area of the entry tear were compared. The % circumference for propagation of thin flap (47 ± 1%) was not significantly different (p = 0.14) from thick flap (44 ± 2%). On the contrary, the axial length of propagation for thin flap (2.57 ± 0.15 cm) was significantly different (p < 0.05) from the thick flap (1.56 ± 0.10 cm). TL compression was observed during systolic phase. For a fixed geometry of entry tear (%circumference = 39 ± 2%; axial length = 1.43 ± 0.13 cm), mean pressure did not have significant (p = 0.84) effect on flap movement. Increase in pulse pressure resulted in a significant change (p = 0.02) in %TL area (52 ± 4%). The energy acting on the false lumen immediately before propagation was calculated as 75 ± 9 J/m² and was fairly uniform across different specimens. Pulse pressure had a significant effect on the flap movement in contrast to mean pressure. Hence, mitigation of pulse pressure and restriction of flap movement may be beneficial in patients with type B acute dissections.

Development of a patient-specific simulation tool to analyse aortic dissections: assessment of mixed patient-specific flow and pressure boundary conditions

Aortic dissection has high morbidity and mortality rates and guidelines regarding surgical intervention are not clearly defined. The treatment of aortic dissection varies with each patient and detailed knowledge of haemodynamic and mechanical forces would be advantageous in the process of choosing a course of treatment. In this study, a patient-specific dissected aorta geometry is constructed from computed tomography scans. Dynamic boundary conditions are implemented by coupling a three element Windkessel model to the 3D domain at each outlet, in order to capture the essential behaviour of the downstream vasculature. The Windkessel model parameters are defined based on clinical data. The predicted minimum and maximum pressures are close to those measured invasively. Malperfusion is indicated and complex flow patterns are observed. Pressure, flow and wall shear stress distributions are analysed. The methodology presented here provides insight into the haemodynamics in a patient-specific dissected aorta and represents a development towards the use of CFD simulations as a diagnostic tool for aortic dissection.

Infradiaphragmatic malperfusion of acute aortic dissection associated with previous abdominal aortic aneurysm repair

PURPOSE

To evaluate the association of previous abdominal aortic aneurysm (AAA) graft replacement with infradiaphragmatic malperfusion in patients with acute aortic dissection.

METHODS

Between November 2006 and June 2011, 133 patients were referred to our hospital for management of acute aortic dissection. Eight (6.0 %) of these patients had undergone AAA graft replacement prior to the acute aortic dissection. We compared the computed tomography (CT) images of these 8 patients with those of the remaining 125 patients without previous AAA graft replacement, in terms of organ ischemia as a complication induced by acute aortic dissection.

RESULTS

Infradiaphragmatic malperfusion from acute aortic dissection was confirmed in four of the eight patients who had undergone AAA graft replacement. Contrasted CT scan images indicated that the main cause of infradiaphragmatic malperfusion was collapse of the true lumen from compression by the false lumen into the suprarenal aorta. Although there was no significant difference between the groups in terms of cerebral ischemia and myocardial ischemia, bilateral leg ischemia and visceral ischemia occurred more frequently in the patients who had undergone AAA graft replacement.

CONCLUSION

Previous AAA graft replacement is a risk factor for infradiaphragmatic malperfusion in patients with acute aortic dissection.

Mesenteric artery fenestration for type B dissection with visceral ischemia

We describe a successful case of direct superior mesenteric artery fenestration for an acute type B dissection complicated by bowel necrosis in a 68-year-old man. At 11 days after the onset, computed tomography showed superior mesenteric artery obstruction. We fenestrated and connected the true lumen to the false lumen of the superior mesenteric artery, and performed thrombectomy in both lumens. A bowel resection was carried out immediately. The patient was discharged uneventfully after recovery.

[Malperfusion in aortic dissection: diagnostic problems and therapeutic procedures]

Malperfusion of the thoracoabdominal aorta and its side branches is a common complication of aortic dissection, often proving fatal. Vital organ malperfusion accompanying acute aortic dissection is a major cause of mortality and morbidity and requires timely reperfusion of the ischemic organs as well as adequate management of the aortic dissection. Ischemic damage to vital organs supplied by the thoracoabdominal aorta greatly increases the overall risk of aortic dissection. As initial symptoms may be subtle, malperfusion tends to be recognized late, and therefore accounts for a considerable percentage of fatalities.Effective reperfusion is not readily achieved by central aortic surgery alone in a certain number of patients. Various strategies have been used, including entry closure by central aortic surgery or stent grafting, surgical or catheter fenestration, bypass grafting and percutaneous stenting.Endovascular bare-metal stent placement is an attractive and promising treatment option since it is readily available, is less invasive and presents fewer risks to the patient.

Effect of chronic dissection on early and late outcomes after descending thoracic and thoracoabdominal aneurysm repair

OBJECTIVE

Although chronic aortic dissection (CD) has traditionally been considered a predictor of perioperative morbidity and mortality after descending thoracic/thoracoabdominal aneurysm repair (thoracoabdominal aortic aneurysm [TAA]), recent reports have rejected this assertion. Still, few contemporary studies document late outcomes after TAA for CD, which is the goal of this study.

METHODS

From August 1987 to December 2005, 480 patients underwent TAA; 73 (15%) CD and 407 (85%) degenerative aneurysms (DA). Operative management consisted of a clamp-and-sew technique with adjuncts in 53 (78%) CD and 355 (93%) DA patients (P < .001). Epidural cooling was used to prevent spinal cord injury (SCI) in 51 (70%) CD and 214 (53%) DA patients (P = .007). Study end points included perioperative SCI/mortality, freedom from reintervention, and long-term survival.

RESULTS

CD patients were younger (mean age 64.5 years CD vs 72.5 years DA, P < .001) and more frequently had a family history of aneurysmal disease (23% CD vs 6% DA, P < .001). Forty-three (59%) CD patients had elective TAA (vs 322 (79%) DA, P = .001). Eleven (15%) CD patients had Marfan's syndrome (vs 0% DA, P < .001), and 17 (23%) CD patients had a prior arch or ascending aortic repair (vs 16 [4%] DA, P < .001). CD patients were more likely to have Crawford type I & II thoracoabdominal aneurysms (44 [60%] vs 120 [29%] DA, P < .001), while only two (3%) CD patients had type IV aneurysms (vs 99 [24%] DA). There was no difference in perioperative mortality between the two groups (11% CD vs 8.6% DA, P = .52), nor was there a difference in flaccid paralysis, which occurred in five (7%) CD and 22 (5%) DA patients (P = .92). At 5 years, 70% of CD patients were free from reintervention versus 74% of DA (P = .36). The actuarial survival was 53% and 32% at 5 and 10 years for CD versus 47% and 17% for DA (P = .07).

CONCLUSIONS

Despite increased operative complexity, CD does not appear to increase perioperative SCI or mortality after TAA when compared with DA. Long-term freedom from aneurysm-related reintervention is similar for both groups as is survival, despite patients with CD being of younger age at presentation.

Outcome of open and endovascular repair in acute type B aortic dissection: a retrospective and observational study

Background

The aim of the study was to analyze surgical and endovascular results in the treatment of acute type B aortic dissection (B AAD).

Methods

Retrospective and observational analysis with patient inclusion between January 2001-December 2008 and follow-up ranged from 2 to 96 months (median = 47.2) was performed. Out of 51 consecutive patients with B AAD, 11 (21.6%) had to undergo open surgery (OS) and 13 (25.5%) endovascular treatment (TEVAR).

Results

There was a significantly difference in early mortality in the TEVAR group (0/13,0%) vs OS group (4/11,36.4%, P < 0.05) and in the incidence of paraplegia/paraparesis (OS 2,28.6% vs TEVAR 1,7.7%, P < 0.05), renal failure (OS 3, 42.8% vs TEVAR 1, 7.7%, P < 0.05), respiratory failure (OS 2,28.6% vs TEVAR 1,7.7%, P < 0.05) and cerebrovascular accident (OS 1,14.3% vs TEVAR 0,0%, P < 0.05). The late mortality at a follow-up was 30.8% (4/13) in the TEVAR group and 42.8% (3/7) in the OS group, respectively (P = not significant). The cumulative survival rate after 1, 3 and 8 years was 93%, 84%, and 69% in the TEVAR group and 86%, 71% and 57% in the OS group, respectively. Endoleaks were diagnosed in 2/13 endovascular patients (15.4%).

Conclusions

TEVAR group had a significantly reduction in early mortality and postoperative complications. No significant differences were found in terms of cumulative survival at follow-up. On this basis TEVAR could be considered an option in the treatment of these complex cases with all proper reservation especially related to the small sample sizes examined.

Endovascular repair or medical treatment of acute type B aortic dissection? A comparison

INTRODUCTION

The aim of this retrospective study was to compare the outcome of thoracic endovascular aortic repair (TEVAR) to that of medical therapy in patients with acute type B aortic dissection (TBD).

MATERIALS AND METHODS

From July 1996 to April 2008, 88 patients presenting with acute TBD underwent either TEVAR (group A, n=38) or medical therapy (group B, n=50). Indications for TEVAR were intractable pain, aortic branch compromise resulting in end-organ ischemia, rapid aortic dilatation and rupture. Follow-up was performed postinterventionally, at 3, 6 and 12 months and yearly thereafter and included clinical examinations and computed tomography (CT), as well as aortic diameter measurements and assessment of thrombosis.

RESULTS

Mean follow-up was 33 months in group A and 36 months in group B. The overall mortality rate was 23.7% in group A and 24% in group B, where 4 patients died of late aortic rupture. In group A, complications included 9 endoleaks and 4 retrograde type A dissections, 3 patients were converted to open surgery and 2 needed secondary intervention. None of the patients developed paraplegia. In group B, 4 patients were converted to open surgery and 2 to TEVAR. The maximal aortic diameter increased in both groups. Regarding the extent of thrombosis, our analyses showed slightly better overall results after TEVAR, but they also showed a tendency towards approximation between the two groups during follow-up.

CONCLUSION

TEVAR is a feasible treatment option in acute TBD. However, several serious complications may occur during and after TEVAR and it should therefore be reserved to patients with life-threatening symptoms.

Descending Thoracic Aortic Dissection: Evaluation and Management in the Era of Endovascular Technology

Acute aortic dissection is a relatively uncommon but highly lethal condition. Without proper treatment, devastating consequences can occur due to aortic rupture, cardiac tamponade, or irreversible ischemia involving the spinal cord or the visceral organs. The treatment strategy of this condition is in part influenced by the location and the severity of aortic dissection as immediate surgical intervention is necessary in acute ascending aortic dissection, whereas medical therapy is the initial treatment approach in uncomplicated descending aortic dissection. Recent advances of endovascular technology have broadened the potential application of this catheter-based therapy in aortic pathologies, including descending thoracic aortic dissection. In this article, the etiology, pathogenesis, and classification of this condition are discussed. The diagnostic benefits of various imaging modalities for descending aortic dissection are also discussed. Current treatment strategies, including medical, surgical, and catheter-based interventions, are reviewed. Lastly, clinical experiences of endovascular treatment for descending aortic dissection and various endovascular devices potentially applicable for this condition are discussed.

Stent Grafting–Related Acute Type B Redissection

The purpose of this article is to report two distal dissections resulting as a complication of endovascular aneurysm repair (EVAR) in two cases of type B aortic dissection (TBAD) and its relationship with prosthetic alignment at the distal landing zone. Two patients affected by aneurysm formation of a chronic type B dissection underwent EVAR. During postoperative follow-up, at 48 and 39 months, respectively, a new chest pain episode recommended a new computed tomographic angiography examination. New false lumen reperfusion and increased aortic diameter distally to the prosthesis were demonstrated. The distal end of each stent graft showed an angulated alignment to the proximal descending aorta at the point of the secondary entry site. Both patients were successfully treated after deployment of a distal endograft. Prosthetic alignment with the aortic axis is important to avoid wall stress and secondary perforation in patients treated for TBAD. The distal landing point at the descending aortic straight segment is recommended.

A Fatal Complication Following Hybrid Total Arch Replacement with Supra-aortic Artery Translocation and Endovascular Stenting

This case highlights the successful management of acute Type B dissection complicated by visceral malperfusion. Even though the procedure of hybrid supra-aortic translocation and endovascular stenting corrected the malperfusion, it is important for vigilant CT scan surveillance for the post operative complications which can occur with this procedure.

Descending thoracic aortic dissections

Type B dissection has traditionally been managed medically if uncomplicated and surgically if associated with complications. This practice has resulted in most centers reporting significant morbidity and mortality if open repair is required. In the setting of malperfusion, operative repair has been conjoined with fenestration or visceral stenting to improve outcomes. Endovascular stent grafts seem to offer an attractive alternative in the acute complicated type B dissection, with reduced mortality and morbidity, particularly paralysis, compared with open repair. It is reasonable to consider endovascular stent grafts as another tool in managing dissection, but to recognize that open surgical repair still plays an important role, and that the data that define indications and outcomes are still emerging.

[Cardiac tamponade due to rupture of healed and sealed aortic intimomedial tear--case report]

INTRODUCTION

The healed and sealed intimomedial aortic tears showed clearly defined edges and U-shaped defect of the tissue extending from intima into the media of a varying depth, filled by paler tissue with smooth surface. These tears can be solitary or multilocular, localized in different parts of the aorta, followed by limited intramural incomplete dissection. They can be provoked by diseases or injury. This part of the aortic wall filled with scar tissue is very vulnerable and could be the site of new rupture, followed by tamponade or fatal internal bleeding.

CASE OUTLINE

In this paper, we report a case of unexpected unknown death of a young male, 26-years-old, found on the ground, near his car. At autopsy, we established the old healed and open intimomedial tear on the posterior wall of the ascending aorta, with a remaining little dissection flap. This part of the wall with scar tissue was ruptured, causing bleeding in the pericardial sac, and tamponade. Histologically, the early stage of cystic medial degeneration was recognized. There were no injuries of the skin, soft tissue and bones.

CONCLUSION

In the paper, we discussed the manner of death in this case, as well as the medicolegal implications.

Management of vital organ malperfusion in acute aortic dissection: proposal of a mechanism-specific approach

OBJECTIVE

We report our strategy for malperfusion accompanying acute aortic dissection, especially that involving the abdominal organs, which is based on the mechanism and includes percutaneous management.

METHODS

From 1991 through October 2005, a total of 38 of 135 (28%) patients with acute dissection presented with organ malperfusion. Altogether, 31 had type A dissection. The involved vascular territories were coronary in 8, brain in 16, celiac and superior mesenteric in 6, renal in 10, and lower limb in 13. For the abdominal organs, the mechanisms of the malperfusion were classified into the aortic type (n = 3) and the branch type (n = 13). The branch type was further divided into the orifice type (n = 8) and distal type (n = 5). All but one patient with type A dissection underwent a central aortic operation with resection of the entry site. Revascularization of the ischemic organ was added by bypass grafting or direct reconstruction. Distal organ malperfusion accompanying type B dissection was treated by the mechanism-specific approach. That is, the aortic type was treated by surgical fenestration, whereas the branch type was treated by percutaneous stenting.

RESULTS

The one hospital death (2.6%) was due to brain infarction. Although a central aortic operation alone successfully reversed aortic-type malperfusion in all three patients, it was not effective for branch-type malperfusion in five of six vascular territories. Surgical fenestration did not successfully reverse branch-type renal malperfusion in two patients. Percutaneous stenting was successful in all three vessels with branch-type malperfusion.

CONCLUSION

Central aortic operation or fenestration is effective for aortic-type malperfusion, whereas the branch type may require stenting or bypass grafting.

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.

Stent-graft treatment for isolated infrarenal aortic dissecting aneurysms

OBJECTIVES

We report three cases of isolated infrarenal aortic dissecting aneurysms managed with stent-graft.

MATERIALS AND METHODS

Three patients, two men and one woman, with a mean age at diagnosis of 69 years were identified. In all cases, chest CT-A did not reveal evidence of thoracic aortic dissection. The mean maximal aneurysm diameter was 6.7+/-1.5 cm (range: 5.5-8 cm). All patients underwent stent-graft repair. Follow-up computed tomographic (CT)-angiography examinations were scheduled 1, 4, and 12 months after the procedure.

RESULTS

Stent-graft deployment was technically successful in all cases. Intraoperative mortality was not observed. All patients were adequately treated with a bifurcated device. Intensive care unit (ICU) stay was never required. Mean hospitalization was 4.6 days (range: 4-6 days). Mean follow-up was 18 months. No stent-graft-related complications were observed.

CONCLUSIONS

Endovascular repair for isolated infrarenal abdominal aortic dissecting aneurysms is feasible and effective.

Percutaneous mesenteric stenting followed by laparoscopic exploration for visceral malperfusion in acute type B aortic dissection

A 55-year-old man underwent percutaneous mesenteric and left renal stenting for malperfusion in acute type B aortic dissection. Laparoscopic exploration was performed immediately after percutaneous revascularization to ensure the integrity of the abdominal viscera. Because the diagnosis of mesenteric infarction may sometimes be difficult and its delay can be fatal, we advocate laparoscopic exploration as a mini-invasive method after percutaneous management of visceral malperfusion, if the integrity of the abdominal viscera needs to be verified.

Stent-graft repair for thoracic aortic disease: results of an independent nationwide study in France from 1999 to 2001

BACKGROUND

The purpose of this study was to assess the overall short-term outcome of stent-graft repair for thoracic aortic disease in France between June 1999 and May 2001.

METHODS

This retrospective study was designed by the French National Health Insurance Fund for Salaried Workers. To ensure objectivity, data were retrieved at each center and checked by a team of medical advisors.

RESULTS

Between June 1999 and May 2001, a total of 166 stent-graft repairs for thoracic aortic disease were performed in 166 patients, mainly by surgeons in the operating room (88%). Patients were classified according to the American Society of Anesthesiologists as status I or II in 24% of cases, status III in 56%, and status IV or V in 20%. The diameter of the thoracic aneurysm was less than 50 mm in 17% of cases. Seventeen patients (10%) died during the first 3 months, including 8 within the first 30 days after the procedure. A total of 49 complications were noted in 34 patients (20.5%). Endoleaks occurred in 27 patients (16.3%), including 8 that necessitated further treatment. Other stent-related complications included rupture (n = 3), aortoesophageal or tracheal fistula (n = 3), paraplegia (n = 6), stent migration (n = 2), visceral embolism (n = 5), and cerebral embolism (n = 2). There were 14 delivery-related complications (8%) at the catheterization site. Non-stent-related complications occurred in 14 (8%).

CONCLUSIONS

This nationwide study demonstrates that stent-graft repair for thoracic aortic disease can be performed with acceptable postoperative morbidity. However, it is not a risk-free procedure and should continue to be used in an investigative setting.

Endovascular stent-graft placement for complications of acute type B aortic dissection

PURPOSE OF REVIEW

To review the concepts and current clinical results of endovascular stent-graft placement for acute complicated type B aortic dissection.

RECENT FINDINGS

The optimal treatment for patients with dissections confined to the descending aorta (Stanford type B-AD) remains a matter of debate. Usually, antihypertensive medical therapy with strict blood pressure lowering below 135/80 mm Hg represents the first choice for patients with uncomplicated type B-AD. Patients with acute complicated type B-AD remain a major therapeutic challenge because surgery of the descending aorta is still associated with high morbidity and mortality. In 1999, endovascular stent-graft placement was introduced as a novel, less invasive treatment option for patients with type B aortic dissection. Current indications include acute (contained) aortic rupture, symptomatic ischemic branch vessel involvement, early aortic expansion, or unrelenting pain. So far, few studies on stent-graft placement in patients with acute complicated aortic dissection have been published reporting an early mortality between 0 and approximately 20%.

SUMMARY

To date, there is limited experience with endovascular stent-graft placement for acute complicated type B aortic dissection demonstrating its feasibility and life-saving potential. The endovascular approach can avoid the major trauma of open surgery and should help to get patients out of the acute life-threatening phase of the disease; however, long-term results are needed to assess the durability of this treatment.

Type A Dissection Following Endovascular Thoracic Aortic Stent-Graft Repair

PURPOSE

To describe our experience with endovascular stent-graft repairs in the thoracic aorta focusing on the secondary complication of type A dissection.

METHODS

Between January 1996 and April 2004, 73 patients were treated for traumatic thoracic aortic rupture (n=15), type B dissection (n=22), or atherosclerotic descending thoracic aortic aneurysms (TAA, n=36). A retrospective review of the records found 5 (6.8%) patients (3 men; median age 64 years, range 43-87) who experienced a type A dissection at a median 20 days (range 2-124) after thoracic stent-graft repair for 3 type B dissections, 1 TAA, and a late type I endoleak that appeared 28 months after initial stent-graft repair of a traumatic dissection.

RESULTS

In 3 patients (2 dissections, 1 endoleak), a tear in the aortic wall at the proximal stent-graft was responsible for a retrograde type A dissection. Underlying disease was the cause of the type A dissection in the 2 other patients (1 dissection, 1 TAA) and was unrelated to the stent-grafts. Three patients underwent open surgery at 3, 26, and 124 days after stent-graft placement; 2 procedures were successful, but the third patient died 3 months later due to multiorgan failure. Two type A dissections were untreated: one patient died from cardiac tamponade 14 days after successful stent-graft exclusion of the type I endoleak; the other patient refused further treatment and survived. The procedure-related mortality following acute retrograde type A dissection was 40%.

CONCLUSIONS

Endovascular stent-graft repair of the thoracic aorta is associated with lower morbidity and mortality rates than surgical repair, although potentially lethal complications, acute or delayed, may occur.

Endovascular treatment of basilar artery dissection by stent deployment. A case report

SUMMARY

We describe a 44 year-old woman with dissection of the distal third of the basilar artery presenting with subarachnoid haemorrhage. She was treated with a Neuroform stent (Boston Scientific), the first stent designed for intracranial navigation and recently approved by the FDA to treat wide-necked cerebral aneurysms and allow reconstruction of the internal lumen. In our patient, the dissection involved the origin of the anterosuperior cerebellar artery and the origin of the right posterior cerebral artery. The stent was positioned without complications during or after the procedure. Intra and periprocedural thrombolytic therapy was given followed by an antiaggregant (100 mg Aspirin) for a year after treatment. Subsequent angio-MR and angiographic monitoring disclosed resolution of the dissection and normalization of the basilar artery lumen. She currently lives a controlled but normal life.