HTA supporting clinical practice: the case of surgical repair of thoracoabdominal aortic aneurysms

Background

Thoracoabdominal aortic aneurysms (TAAAs) are defined as those aortic aneurysms involving renovisceral arteries. They account for around 10% of aortic aneurysms, and their treatment is burdened by considerable mortality and morbidity. Open surgical repair has been practised as the standard of care since the 1950s. In 2001 endovascular repair was introduced to reduce treatment invasiveness, and the technology is still evolving. The potential benefits of endovascular repair over open surgery should be carefully weighed in a multidimensional framework.

Methods

We applied the Health Technology Assessment (HTA) framework (EUnetHTA core model with 9 dimensions) to conduct a report comparing the two technologies. A multidisciplinary working group was established. We derived and pooled: i) secondary data derived from systematic literature reviews, and ii) original data from IRCCS San Raffaele Hospital, Milan, a national referral centre for TAAA (qualitative and economic data).

Results

Endovascular repair resulted superior to the traditional open surgery in terms of efficacy and safety, as justified by the meta-analysis we performed. Despite the higher costs, a significant impact on budget and slightly lower cost-effectiveness, the endovascular protheses’ adoption could provide conspicuous benefits in terms of social and ethical dimensions without affecting long-term organisational and legal aspects.

Conclusions

The multi-criteria decision analysis carried out from a hospital point of view shows that there is no significant difference (final score endovascular repair 0.68 vs open surgery 0.63) between the two procedures considering all the dimensions. Still, the endovascular repair is slightly superior to the open surgery in terms of safety, effectiveness, social, ethical, legal, and organisational impact. From the policy maker’s point of view, technologies with a score superior to 0.6 are equally valuable, and the final decision should be left to the clinicians.

Key messages

• Further research is needed to compare endovascular prostheses and open surgery’s long-term population benefits, balancing clinical, economic, organisational and patient-related outcomes.

• HTA methodology offers substantial support to compare in-use technologies, informing clinicians’ and decision-makers’ choices to strengthen healthcare provision equity and preparedness.

An anatomical review of spinal cord blood supply

Knowledge of the spinal cord (SC) vascular supply is important in patients undergoing procedures that involve the thoracic and thoracoabdominal aorta. However, the SC vasculature has a complex anatomy, and teaching is often based only on anatomical sketches with highly variable accuracy; historically, this has required a "leap of faith" on the part of aortic surgeons. Fortunately, this "leap of faith" is no longer necessary given recent breakthroughs in imaging technologies and postprocessing software. Imaging methods have expanded the non-invasive diagnostic ability to determine a patient's SC vascular pattern, particularly in detecting the presence and location of the artery of Adamkiewicz. CT is the imaging modality of choice for most patients with thoracic and thoracoabdominal aortic disease, proving especially useful in the determination of feasibility and planning of endovascular treatment. Thus the data set required for analysis of SC vascular anatomy is usually already available. We have concentrated our efforts on CT angiography, which offers particularly good imaging capabilities with state-of-the-art multidetector scanners. Multidetector row helical CT provides examinations of an extensive range in the craniocaudal direction with thin collimation in a short time interval, giving excellent temporal and spatial resolution. This paper provides examples of the SC vasculature imaging quality that can be obtained with 64 row scanners and appropriate postprocessing. Knowledge of the principal anatomical features of the SC blood supply of individual patients undergoing open or endovascular thoracoabdominal procedures has several potential benefits. For open surgery, analysis of the SC vasculature could tell us the aortic region that feeds the Adamkiewicz artery and thus needs to be reimplanted. For endovascular procedures, we can determine whether the stent-graft will cover the Adamkiewicz artery, thus avoiding unnecessary coverage. CT data can also be used to stratify risk of SC ischemia and guide the selective use of spinal cord injury prevention strategies.

Clinical use of extra-large self-expanding stents

The aim of this study is to describe our clinical experience with an extra-large self-expandable stent specifically designed to treat aortic lesions (E-XL, Jotec GmbH, Hechingen, Germany), now commercially available in Europe. The E-XL was used at our Institution in 14 patients (mean age, 56±12 years; 9 males) with the following indications: improve proximal fixation (4 cases), type I endoleak (2 cases), aortic dissection with static malperfusion (1 case) and dynamic malperfusion (7 cases). Early results have been shown to be safe and effective in different clinical settings, including in emergency cases. This peculiar aortic stent could be useful in the armamentarium of the endovascular surgeon.

Redo surgery in ascending aorta and aortic arch

AIM

Reinterventions following previous ascending aorta and aortic arch repair are uncommon, but technically challenging and often burdened with high morbidity and mortality. The aim of this article is to present a single-center experience in the treatment of this complex pathology, using different surgical approaches.

METHODS

Between 1999 and 2014, 17 patients (14 males, mean age 73±16 years) underwent ascending aorta and aortic arch redo surgery at our Department. A prospectively maintained database including thoracic aortic procedures was reviewed retrospectively to collect data on redo patients.

RESULTS

In 13 cases the index procedure was an endovascular or hybrid procedure on the aortic arch performed at our Department, for an in-house reintervention rate of 6.9% (13/188). In 10 cases the cause of reintervention was stent-graft distal migration, treated by means of endovascular relining in all cases, associated with adjunctive supra-aortic trunks debranching via sternotomy in 6 cases. In 5 cases the cause of reintervention was retrograde ascending aortic dissection, in 1 case ascending aortic anastomotic pseudoaneurysm following supra-aortic trunk debranching, and in 1 case mediastinitis following implantation of an endovascular plug previously used to treat an ascending aortic pseudoaneurysm. In these last 7 cases, all patients were treated by means of ascending and arch surgical replacement under deep hypothermic circulatory arrest (DHCA) and antegrade cerebral perfusion (ACP). No 30-day mortality was observed. Major perioperative morbidity included 1 paraplegia, 1 minor stroke, 1 bleeding requiring reintervention, and 3 cases of respiratory failure requiring prolonged intubation (2) or tracheostomy (1).

CONCLUSION

In our experience, incidence of serious complications requiring reinterventions following ascending aorta or aortic arch repair is not negligible. Redo surgery in ascending aorta and aortic arch is feasible in high-volume and experienced centers, as it often requires hybrid repair via midline sternotomy, or surgical replacement under DHCA and ACP.

Technical features of the INCRAFT™ AAA Stent Graft System

The INCRAFT® AAA Stent Graft System is the advanced endovascular aneurysm repair (EVAR) technology for the treatment of infrarenal abdominal aneurysms. This new system is designed to address the unmet needs of current endografts by combining unique features and adding new refinements compared to existing endografts delivered through a flexible 14-Fr ultra-low system. The INCRAFT® AAA Stent Graft System introduces innovative features without deviating from proven stent-graft design principles. It is a three-piece modular system, made of low porosity polyester and segmented nitinol stents. However, the introduction of cap-free delivery and partial proximal repositioning enhances the ability of the device to better match individual aortoiliac anatomy with a high deliverability and placement accuracy in a easy to use system. Moreover, the INCRAFT® System allows a "customization" of the implant during the procedure with bilateral in-situ length adjustment features. The present data from the ongoing clinical trials confirm excellent results with this system, but postmarket studies will be necessary to verify the effectiveness of this system in the real-world setting.

BRAVISSIMO: 12-month results from a large scale prospective trial

The BRAVISSIMO study is a prospective, non-randomized, multi-center, multi-national, monitored trial, conducted at 12 hospitals in Belgium and 11 hospitals in Italy. This manuscript reports the findings up to the 12-month follow-up time point for both the TASC A&B cohort and the TASC C&D cohort. The primary endpoint of the study is primary patency at 12 months, defined as a target lesion without a hemodynamically significant stenosis on Duplex ultrasound (>50%, systolic velocity ratio no greater than 2.0) and without target lesion revascularization (TLR) within 12 months. Between July 2009 and September 2010, 190 patients with TASC A or TASC B aortoiliac lesions and 135 patients with TASC C or TASC D aortoiliac lesions were included. The demographic data were comparable for the TASC A/B cohort and the TASC C/D cohort. The number of claudicants was significantly higher in the TASC A/B cohort, The TASC C/D cohort contains more CLI patients. The primary patency rate for the total patient population was 93.1%. The primary patency rates at 12 months for the TASC A, B, C and D lesions were 94.0%, 96.5%, 91.3% and 90.2% respectively. No statistical significant difference was shown when comparing these groups. Our findings confirm that endovascular therapy, and more specifically primary stenting, is the preferred treatment for patients with TASC A, B, C and D aortoiliac lesions. We notice similar endovascular results compared to surgery, however without the invasive character of surgery.

The best treatment of juxtarenal aortic occlusion is and will be open surgery

Occlusion of the infrarenal aorta (IAO) represents from 3% to 8.5% of aortoiliac occlusive diseases, and is a variant of TransAtlantic Inter-Society Consensus (TASC) Type D lesions. Two different patterns of IAO can be identified: Distal and proximal, or iuxtarenal. The former typically spares the origin of the inferior mesenteric artery, and is associated with the classic Leriche clinical triad. The latter extends cephalad approaching the level of the renal arteries, and may also cause acute renal failure, intestinal infarction, and even paraplegia due to the proximal propagation of aortic thrombosis. Endovascular treatment for TASC Type C and D lesions as a whole provides impressive results in terms of periprocedural morbidity, secondary patency rates, and of course less invasivity in comparison to open surgery. However, when complete aortic occlusions, and particularly juxtarenal occlusion, are specifically addressed, the reported results are in fact sobering, both in terms of technical success rates, and perioperative complications. Surgery repair of juxtarenal aortic occlusion, namely aortic endarterectomy and bypass grafting, is a challenging procedure that requires almost invariably aortic cross-clamping above the level of the renal arteries, and may be associated with significant morbidity and mortality. Nevertheless, it currently provides unmatched perioperative and long-term results, and should be regarded as the treatment of choice.

Hybrid procedures for the treatment of thoracoabdominal aortic aneurysms and dissections

The search for less invasive therapeutic approaches to thoracoabdominal aortic aneurysms (TAAAs) brought endovascular procedures to establish themselves as alternatives to open surgery in high-risk patients. Aim of this study is to illustrate the hybrid - open and endovascular - treatment of dissecting and non-dissecting TAAAs, and to analyze short and midterm results at our Center. We analyzed 41 high-risk patients who underwent hybrid TAAA repair (dissecting TAAA in 17% of cases) with a variety of visceral rerouting configuration and of commercially available thoracic endografts. Thirty-one simultaneous (76%) and 10 staged procedures (24%) were performed with a four-vessel revascularization in 13 cases (32%), a three-vessel in 9 (22%) and a two-vessel in 19 (46%). No intraoperative deaths were observed in our series, with a technical success in endovascular TAAA repair of 100%. Two patients died in the intersurgical time. A perioperative mortality of 13% and a perioperative morbidity of 32% were recorded, including one case (2.4%) of permanent paraplegia. At a median follow-up of 23.3 months, we observed a visceral graft occlusion rate of 6%, three type II endoleak and one endograft migration. Six patients died for unrelated events. Typical complications of conventional TAAA open surgery have been not eliminated by hybrid repair and still significant mortality and morbidity have been reported. Dissecting etiology did not negatively affect the outcome of hybrid repair in our experience. Fate of visceral bypasses and incidence of endoleak and other endograft-related complications need to be carefully assessed. Hybrid TAAA repair should nowadays be limited as alternative to simple observation in patients unfit for the conventional open repair.

Endovascular treatment of descending thoracic aneurysms

INTRODUCTION

Current strategies for repair of descending thoracic aortic aneurysms consist of open repair with surgical graft replacement or thoracic endovascular aortic repair. We review and update our overall experience in aortic thoracic diseases and specifically analyzed our outcomes with thoracic endovascular aortic repair in patients with descending thoracic aortic aneurysms.

METHODS

From 1993 to present a total of 1144 patients were treated in our Center for pathology involving the thoracic aorta. Since 1998, 322 patients underwent thoracic endovascular aortic repair, and among this group, in 188 cases the descending aorta was involved. In 74% of patients treated for a descending thoracic aortic lesion, a degenerative aneurysm was observed.

RESULTS

In patients with descending thoracic aortic aneurysms receiving thoracic endovascular aortic repair, our technical success rate, i.e. deployment of endograft with complete exclusion of the lesion/minimal endoleak, was 99.5% (one case required emergent open conversion) with a perioperative mortality of 2.6% (five patients). The rate of spinal cord ischemia, manifesting either as paraplegia or paraparesis, was 4.7%. Delayed onset spinal cord ischemia ameliorated with adequate arterial pressure and cerebrospinal fluid drainage.

CONCLUSIONS

Our experience of selected patients undergoing thoracic endovascular aortic repair of descending thoracic aorta aneurysms is satisfactory with very low mortality and morbidity. A large use of thoracic endovascular aortic repair is foreseen in the next future.

Management of thoracoabdominal aortic aneurysms

Conventional treatment of thoracoabdominal aortic aneurysms (TAAAs) consists of graft replacement with reattachment of the main aortic branches. Over the past 20 years a multimodal approach has gradually evolved to reduce the trauma of surgery by maximizing organ protection, allowing experienced surgical Centers to have better outcomes than previously reported. However, mortality and morbidity associated to TAAA open repair remain significant. Hybrid repair, consisting of open aortic debranching and revascularization followed by endovascular exclusion of the aneurysm, may extend the indications of TAAA repair to high-risk patients that cannot benefit from surgery, however results are still under evaluation. Aim of this paper is to illustrate the management and results of thoracoabdominal aortic aneurysms surgery with open techniques of organ protection and hybrid approach in our Center.

Results of Endografting of the Aortic Arch in Different Landing Zones

INTRODUCTION

Endovascular approach to the aortic arch is an appealing solution for selected patients. Aim of this study is to compare the technical and clinical success recorded in the different anatomical settings of endografting for aortic arch disease.

METHODS

Between June 1999 and October 2006, among 178 patients treated at our Institution for thoracic aorta disease with a stent-graft, the aortic arch was involved in 64 cases. According to the classification proposed by Ishimaru, aortic "zone 0" was involved in 14 cases, "zone 1" in 12 cases and "zone 2" in 38 cases. A hybrid surgical procedure of supraortic debranching and revascularization was performed in 37 cases to obtain an adequate proximal aortic landing zone.

RESULTS

"Zone 0" (14 cases). Proximal neck length: 44+/-6mm. Initial clinical success 78.6%: 2 deaths (stroke), 1 type Ia endoleak. At a mean follow-up of 16.4+/-11 months the midterm clinical success was 85.7%. "Zone 1" (12 cases). Proximal neck length: 28+/-5mm. Initial clinical success 66.7%: 0 deaths, 4 type Ia endoleaks. At a mean follow-up of 16.9+/-17.2 months the midterm clinical success was 75.0%. "Zone 2" (38 cases) Proximal neck length: 30+/-5mm. Initial clinical success 84.2%: 2 deaths (1 cardiac arrest, 1 multiorgan embolization), 3 type Ia endoleaks, 1 case of open conversion. Two cases of delayed transitory paraparesis/paraplegia were observed. At a mean follow-up of 28.0+/-17.2 months the midterm clinical success was 89.5%.

CONCLUSIONS

Total debranching of the arch for "zone 0" aneurysms allowed to obtain a longer proximal aortic landing zone with lower incidence of endoleak, however a higher risk of cerebrovascular accident was observed. The relatively high incidence of adverse events in "zone 1" could be associated to a shorter proximal neck, therefore this landing zone is reserved for patients unfit for sternotomy. In case of endoleak, discovered after a satisfactorily positioned endograft in the arch, the rate of spontaneous resolution within the first 6 months is high.

Ruptured abdominal aortic aneurysm in the elderly patient

The authors discuss several aspects of the management of ruptured abdominal aortic aneurysm in elderly patients. The cost-effectiveness and indications of repair of rAAA in elderly patients are analysed. A literature survey of risk-factors and results of open treatment of rAAA in elderly patients is made. The challenge of endovascular repair of rAAA in the elderly patient is discussed. Finally, the authors report their personnal experience with AAA repair in 163 patients aged 75 years and older, operated on between January 2003 and September 2005(89 endoaneurysmal stentgrafts and 74 open repairs, 42 rAAA,23 symptomatic AAA and 98 selective asymptomatic AAA).

Endovascular Treatment of Aortic Arch Aneurysms

INTRODUCTION

The aim of this study was to review our clinical experience with endovascular treatment of aortic arch aneurysms using different commercially available grafts (Gore, Talent, Endomed, Cook).

METHODS

From 1999 to 2004, 97 patients received endovascular treatment for diseases of the thoracic aorta. In 30 cases (26 males, 4 females) the aortic arch was involved. The left subclavian artery was overstented (Ishimaru zone '2') in 18 cases (60%). Only in the first three cases had the subclavian artery been revascularized. The left common and subclavian arteries were covered (zone '1') in 6 (20%) cases-all had the carotid artery reconstructed, either simultaneously (five cases) or as a staged procedure (one case). Finally, the whole aortic arch was over-stented (zone '0') in 6 (20%) cases, with simultaneous (five cases) or staged (one case) grafting of the supra-aortic vessels from the ascending aorta.

RESULTS

Perioperative mortality was 2/30 (7%), due to graft migration (zone '2') and intra-operative stroke (zone '0'), respectively. One minor stroke was observed. No cases of paraplegia were recorded. Three type I endoleaks were observed. Two resolved at 6 months follow-up; one zone '0' graft is still being followed. There was one surgical conversion for endograft failure 2 weeks after implantation. Thus, the technical success rate was 87% (26/30) cases. The mean follow-up time was 23+/-17 months. No new onset endoleaks or aneurysm-related deaths were recorded.

CONCLUSIONS

Currently available grafts may be deployed in the aortic arch in most instances. De-branching of the aortic arch with surgical revascularization for zone '0' and '1' seems to be adequate to obtain a satisfactory proximal landing zone.