Ten years experience of thoracic and thoracoabdominal aortic aneurysm surgical repair: lessons learned

Outcomes following Management of Complex Thoracoabdominal Aneurysm by an Open Approach

BACKGROUND

In the last decade, advances in surgical techniques, and the introduction of adjuncts for organ protection, have modified the approach for thoracoabdominal aortic aneurysm (TAAA) surgical repair. The aim of this study is to determine whether the contemporary approach influenced the outcomes.

METHODS

From 1989 to 2022, patients who had received elective open surgical repair (OSR) for TAAA at our institution were retrospectively analyzed. This series has been divided in two groups: Group 1 (1989-2009), and Group 2 (2010-2022). Patients included in Group 1 were those treated with a selective use of adjuncts, and Group 2 included patients treated with the systematic use of adjuncts.

RESULTS

A total of 1107 patients were treated (Group 1: 455; Group 2: 652). The surgical management was significantly different between the two groups. The in-hospital mortality was significantly different between the two groups (Group 1: 13.4%, Group 2: 8.1%; p 0.004), as was the rate of permanent spinal cord ischemia (Group 1: 11.9%, Group 2: 7.8%; p 0.023). Renal and respiratory failure were reduced in Group 2, but not significantly.

CONCLUSIONS

The use of the adjuncts enabled the achievement of improvement in mortality and SCI prevention in TAAA OSR. Although a refined surgical technique, mortality and morbidity are still noteworthy in this complex aortic field.

Endovascular repair of intercostal and visceral aortic patch aneurysms following open thoracoabdominal aortic aneurysm repair

PURPOSE

Reoperative open surgical repair (OSR) of thoracoabdominal aortic aneurysms (TAAAs) is associated with high morbidity and mortality. The aim of this study was to analyze outcomes of fenestrated-branched endovascular aneurysm repair (F-BEVAR) for the treatment of intercostal or visceral aortic patch aneurysms after OSR of TAAAs.

METHODS

We reviewed the clinical data and outcomes of consecutive patients treated at 8 academic centers by F-BEVAR for visceral and intercostal aortic patch aneurysms after OSR of TAAAs (2011-2019). All patients had involvement of at least one target vessel requiring incorporation by a fenestration or directional branch. End points were technical success, 30-day and/in-hospital mortality, major adverse events, patient survival, target vessel patency/instability, and freedom from reintervention.

RESULTS

There were 29 patients with a median age of 70 (interquartile range, 63-74) years. Seven patients (24%) had connective tissue disorders. Technical success was 100%. There were no 30-day/in-hospital mortalities. Major adverse events occurred in 5 patients (17%), including estimated blood loss >1 L in 3 patients (10%), acute kidney injury and respiratory failure in 2 patients (7%) each, and transient paraparesis in 1 patient (3%). Median follow-up was 14 (interquartile range, 7-37) months. At 2 years, primary and secondary patency, freedom from target artery instability, freedom from reintervention, and patient survival were 95%, 100%, 83%, 61%, and 96%, respectively.

CONCLUSIONS

F-BEVAR could be considered as an alternative to reoperative OSR in patients with visceral or intercostal aortic patch aneurysms. This series showed no mortality and a low rate of major adverse events, but a significant need for reintervention.

HOXA cluster antisense RNA 2 elevates KIAA1522 expression through microRNA-520d-3p and insulin like growth factor 2 mRNA binding protein 3 to promote the growth of vascular smooth muscle cells in thoracic aortic aneurysm

AIMS

Recently, long non-coding RNAs (lncRNAs) have been revealed to mediate smooth muscle dysfunction in thoracic aortic aneurysm (TAA). LncRNA HOXA-AS2 has been proposed to engage in the regulation of diverse diseases. However, its function in TAA remains unknown. This study aimed to reveal the role and mechanism of HOXA-AS2 in VSMCs which were implicated in TAA formation.

METHODS AND RESULTS

RT-qPCR or western blot was performed to detect RNA or protein expression levels. The role of HOXA-AS2 in VSMCs was explored by functional assays. The relationship among HOXA-AS2/miR-520d-3p/KIAA1522/IGF2BP3 was analysed via mechanism assays. HOXA-AS2 was detected to have significantly high expression in TAA tissues and function as an oncogene to promote proliferation of VSMCs, while inhibiting cell apoptosis (Figure 1, **P < 0.01). HOXA-AS2 was unveiled to bind with miR-520d-3p (Figure 2, *P < 0.05, **P < 0.01) and further up-regulate KIAA1522 to facilitate the growth of VSMCs (Figure 3-4, *P < 0.05, **P < 0.01). HOXA-AS2 was also found to recruit IGF2BP3 to stabilize KIAA1522 mRNA (Figure 5, **P < 0.01). All data were displayed as mean ± standard deviation.

CONCLUSIONS

HOXA-AS2 up-regulates KIAA1522 through targeting miR-520d-3p/IGF2BP3 to drive VSMC growth in TAA.

Effect of cerebrospinal fluid pressure elevation on spinal cord perfusion during aortic cross-clamping with distal aortic perfusion

OBJECTIVES

Distal aortic perfusion (DaP) is a widely accepted protective adjunct facilitating early reinstitution of visceral perfusion during extended thoracic and thoraco-abdominal aortic repair. DaP has also been suggested to secure distal inflow to the paraspinal collateral network via the hypogastric arteries and thereby reduce the risk of spinal cord ischaemia. However, an increase in cerebrospinal fluid (CSF) pressure is frequently observed during thoracoabdominal aortic aneurysm repair. The aim of this study was to evaluate the effects of DaP on regional spinal cord blood flow (SCBF) during descending aortic cross-clamping and iatrogenic elevation of cerebrospinal fluid pressure.

METHODS

Eight juvenile pigs underwent central cannulation for cardiopulmonary bypass according to our established experimental protocol followed by aortic cross-clamping of the descending thoracic and abdominal aorta-mimicking sequential aortic clamping-with the initiation of DaP. Thereafter, CSF pressure elevation was induced by the infusion of blood plasma until baseline CSF pressure was tripled. At each time-point, microspheres of different colours were injected allowing for regional SCBF analysis.

RESULTS

DaP led to a pronounced hyperperfusion of the distal spinal cord [SCBF up to 480%, standard deviation (SD): 313%, compared to baseline]. However, DaP provided no or only limited additional flow to the upper and middle segments of the spinal cord (C1-Th7: 5% of baseline, SD: 5%; Th8-L2: 24%, SD: 39%), which was compensated by proximal flow only at C1-Th7 level. Furthermore, DaP could not counteract an experimental CSF pressure elevation, which led to a further decrease in regional SCBF most pronounced in the mid-thoracic spinal cord segment.

CONCLUSIONS

Protective DaP during thoraco-abdominal aortic repair may be associated with inadequate spinal protection particularly at the mid-thoracic spinal cord level ('watershed area') and result in the adverse effect of a potentially dangerous hyperperfusion of the distal spinal cord segments.

LncRNA Xist induces arterial smooth muscle cell apoptosis in thoracic aortic aneurysm through miR-29b-3p/Eln pathway

BACKGROUND

Thoracic aortic aneurysm (TAA) is a serious disease usually happening in elder people and with high death rate. Accumulating studies have reported that long non-coding RNAs (lncRNAs) are implicated in the progression of various human diseases, including TAA.

AIM

In our study, we intended to explore the function of elastin (Eln) and its upstream mechanism in TAA.

METHODS

RT-qPCR determined gene expressions and western blot tested changes in protein levels. Ang Ⅱ treatment was implemented to induce cell apoptosis. Flow cytometry analysis, TUNEL assay and JC-1 assay were exploited to measure cell apoptosis. Meanwhile, mechanistic assays such as RIP, RNA pull down and luciferase reporter assays were employed to identify the interplay between RNAs.

RESULTS

Eln inhibition was identified to protect rat arterial smooth muscle cells from apoptosis. Also, miR-29b-3p was identified to bind to Eln, and X inactive specific transcript (Xist) could boost Eln expression through absorbing miR-29b-3p. Meanwhile, Eln overexpression counteracted the suppression of silenced Xist on the apoptosis of rat arterial smooth muscle cells. More importantly, such ceRNA network was proved to aggravate the apoptosis of human aortic smooth muscle cells.

CONCLUSION

LncRNA Xist contributes to arterial smooth muscle cell apoptosis through miR-29b-3p/Eln pathway, providing new potential roads for treating TAA.

A new porcine model of ascending aortic aneurysm established using a cover-then-cut method

PURPOSE

To establish a reproducible porcine model of ascending aortic aneurysm (AsAA).

METHODS

We created an AsAA in twelve domestic pigs using a cover-then-cut method, stitching a glutaraldehyde tanned bovine pericardial patch onto the anterolateral aortic wall, then cutting off aortic wall tissue within the patch, and closing the incision in the patch.

RESULTS

The AsAA creation was completed successfully in 11 out of the 12 pigs (91.7%). The mean maximal diameter of the ascending aorta increased significantly by 1.77 times, immediately after the operation (p < 0.05). Significantly continuous expansion of the aneurysm was observed during the follow up period, to 48.9 ± 1.80 mm at 3 months and 50.3 ± 2.25 mm at 6 months (p < 0.05).

CONCLUSIONS

This porcine model of AsAA, created using a repeatable cover-then-cut method, represents a reproducible platform for studying and training, which could contribute to the development of new feasible endovascular treatments of AsAAs.

LncRNA LOXL1-AS is up-regulated in thoracic aortic aneurysm and regulated proliferation and apoptosis of aortic smooth muscle cells

Long non-coding RNA LOXL1-AS is up-regulated in several types of cancers. The present study was carried out to explore the potential interactions between LOXL1-AS and lncRNA Giver in thoracic aortic aneurysm (TAA). We found that LOXL1-AS was up-regulated in TAA patients than in healthy controls in aortic media specimens. Altered expression levels of LOXL1-AS distinguished TAA patients from healthy controls. LncRNA Giver was also up-regulated in TAA patients than in healthy controls in aortic media specimens, and was positively correlated with LOXL1-AS. LOXL1-AS overexpression mediated the up-regulation of Giver in human aortic smooth muscle cells, while Giver overexpression failed to significantly affect LOXL1-AS. LOXL1-AS and Giver overexpression resulted in promoted proliferation and inhibited apoptosis of HAOSMC. Giver silencing played an opposite role and attenuated the effect of LOXL1-AS overexpression. Therefore, LOXL1-AS was up-regulated in TAA and regulated proliferation and apoptosis of LOXL1-AS by up-regulating Giver.

Review: perspectives on renal and visceral protection during thoracoabdominal aortic aneurysm repair

Open repair of a thoracoabdominal aortic aneurysm (TAAA) is an extensive operation and associated with significant perioperative morbidities and mortality, in large part due to distal aortic ischemia secondary to aortic cross-clamping that is necessitated during repair. Distal aortic ischemia may manifest as complications of the kidneys and viscera. Postoperative renal complications range from temporarily elevated levels of creatinine resulting from impaired kidney function to acute renal failure necessitating dialysis that may persist after hospital discharge. Continued advances in the management and adjuncts associated with TAAA repair since the groundbreaking era of E.S. Crawford have led to improved postoperative outcomes following surgery, but the dramatic improvements seen in reducing rates of spinal cord deficits, mesenteric ischemia and other serious postoperative complications have not been seen in contemporary rates of postoperative renal failure. We provide an overview of the various surgical techniques and adjuncts as they relate to the management of visceral and renal ischemia.

Severely Calcified True Aneurysm: A Thought-Provoking Case of Solitary Origin and Postoperative Management

Patient: Male, 70

Final Diagnosis: Splenic artery aneurysm

Symptoms: Asymptomatic

Medication: —

Clinical Procedure: Surgery and Endoscopy

Specialty: Surgery

Identification of EGFLAM, SPATC1L and RNASE13 as novel susceptibility loci for aortic aneurysm in Japanese individuals by exome-wide association studies

We performed an exome-wide association study (EWAS) to identify genetic variants - in particular, low‑frequency or rare variants with a moderate to large effect size - that confer susceptibility to aortic aneurysm with 8,782 Japanese subjects (456 patients with aortic aneurysm, 8,326 control individuals) and with the use of Illumina HumanExome-12 DNA Analysis BeadChip or Infinium Exome-24 BeadChip arrays. The correlation of allele frequencies for 41,432 single nucleotide polymorphisms (SNPs) that passed quality control to aortic aneurysm was examined with Fisher's exact test. Based on Bonferroni's correction, a P-value of <1.21x10-6 was considered statistically significant. The EWAS revealed 59 SNPs that were significantly associated with aortic aneurysm. None of these SNPs was significantly (P<2.12x10-4) associated with aortic aneurysm by multivariable logistic regression analysis with adjustment for age, gender and hypertension, although 8 SNPs were related (P<0.05) to this condition. Examination of the correlation of these latter 8 SNPs to true or dissecting aortic aneurysm separately showed that rs1465567 [T/C (W229R)] of the EGF-like, fibronectin type III, and laminin G domains gene (EGFLAM) (dominant model; P=0.0014; odds ratio, 1.63) was significantly (P<0.0016) associated with true aortic aneurysm. We next performed EWASs for true or dissecting aortic aneurysm separately and found that 45 and 19 SNPs were significantly associated with these conditions, respectively. Multivariable logistic regression analysis with adjustment for covariates revealed that rs113710653 [C/T (E231K)] of the spermatogenesis- and centriole associated 1-like gene (SPATC1L) (dominant model; P=0.0002; odds ratio, 5.32) and rs143881017 [C/T (R140H)] of the ribonuclease A family member 13 gene (RNASE13) (dominant model; P=0.0006; odds ratio, 5.77) were significantly (P<2.78x10-4 or P<6.58x10-4, respectively) associated with true or dissecting aortic aneurysm, respectively. EGFLAM and SPATC1L may thus be susceptibility loci for true aortic aneurysm and RNASE13 may be such a locus for dissecting aneurysm in Japanese individuals.

Hybrid Repair of Thoracoabdominal Aortic Aneurysms Is a Durable Option for High-Risk Patients in the Endovascular Era

Objective:

To report our long-term experience in using the hybrid technique in complex thoracoabdominal aortic aneurysms (TAAAs).

Methods:

Between March 2005 and September 2013, 10 patients with TAAA underwent hybrid procedures with open renovisceral revascularization and thoracoabdominal aortic endografting. Patients were analyzed retrospectively.

Results:

Six men and 4 women with a mean age of 66 years (range 54-81 years) were treated electively during the study period. All 4 visceral vessels were revascularized in 8 patients, whereas 1 patient underwent 3-vessel revascularization and another 2-vessel revascularization. The primary technical success rate was 100%. Eight of the procedures were single staged, and the 2 most recent cases were performed in 2 stages. Perioperative and 30-day mortality was 0%. The mean follow-up was 55 months (4-133 months). None of the patients died due to aortic complications. Major complications included paraplegia (10%, n = 1) and bowel ischemia (n = 1). Postoperative cerebrospinal fluid (CSF) pressure and mean arterial pressure measurements were systematically monitored and corrected. The CSF drainage solved another 4 cases of paraparesis. Three patients required postoperative dialysis, but none of them required permanently. Postoperative spinal cord ischemia and renal complications accumulated in extensive TAAA cases. One renal graft was occluded 45 days after the initial procedure but was successfully treated with thrombolysis. One type I and 1 type III endoleak were noted and successfully treated with an additional stent graft. Two cases of type II endoleak were detected—one with a growing aneurysm sac was treated successfully and another showed no growth and further procedures were abandoned after 2 embolization attempts. In long-term follow-up, 90% of the aneurysms showed shrinkage by a mean of 23 mm (range 7-45 mm).

Conclusion:

The results of hybrid repair on high-risk patients with complex TAAAs are encouraging, and this approach is a valuable alternative when branched and fenestrated endovascular techniques are not considered an option.

Neuromonitoring Using Motor and Somatosensory Evoked Potentials in Aortic Surgery

BACKGROUND

Motor evoked potentials (MEP) and somatosensory evoked potentials (SSEP) are established methods of neuromonitoring aimed at preventing paraplegia after descending or thoracoabdominal aortic repair. However, their predictive impact remains controversial. The aim of this study was to evaluate our single-center experience using this monitoring technique.

METHODS

Between 2009 and 2014, 78 patients (mean age 66 ± 12, 53% male) underwent either descending or thoracoabdominal aortic repairs. Of these, 60% had an aortic aneurysm, 30% dissection, and 10% other etiologies. Intraoperatively, MEPs and SSEPs were monitored and, if necessary, clinical parameters (blood pressure, hematocrit, oxygenation) were adjusted in response to neuromonitoring signals. This analysis is focused on the neurological outcome (paraplegia, stroke) after the use of intraoperative neuromonitoring.

RESULTS

Thirty-day mortality was 10 (12.8%). All patients with continuously stable signals or signals that returned after signal loss developed no spinal cord injury, whereas two out of six of the evaluable patients with signal loss (without return) during the procedure suffered from postoperative paraplegia (one transient and one permanent). Sensitivity and specificity of use of MEP and SSEP were 100% and 94.20% regarding paraplegia, respectively.

CONCLUSIONS

(1) Preservation of signals or return of signals is an excellent prognostic indicator for spinal cord function. (2) Intraoperative modifications in direct response to the signal change may have averted permanent paralysis in the patients with signal loss without neurologic injury. We have found MEP and SSEP neuromonitoring to be instrumental in the prevention of paraplegia. doi: 10.1111/jocs.12739 (J Card Surg 2016;31:383-389).

The mitochondrial division inhibitor mdivi-1 attenuates spinal cord ischemia-reperfusion injury both in vitro and in vivo: Involvement of BK channels

Mitochondrial division inhibitor (mdivi-1), a selective inhibitor of a mitochondrial fission protein dynamin-related protein 1 (Drp1), has been shown to exert protective effects in heart and cerebral ischemia-reperfusion models. The present study was designed to investigate the beneficial effects of mdivi-1 against spinal cord ischemia-reperfusion (SCIR) injury and its associated mechanisms. SCIR injury was induced by glutamate treatment in cultured spinal cord neurons and by descending thoracic aorta occlusion for 20 min in rats. We found that mdivi-1 (10 μM) significantly attenuated glutamate induced neuronal injury and apoptosis in spinal cord neurons. This neuroprotective effect was accompanied by decreased expression of oxidative stress markers, inhibited mitochondrial dysfunction and preserved activities of antioxidant enzymes. In addition, mdivi-1 significantly increased the expression of the large-conductance Ca(2+)- and voltage-activated K(+) (BK) channels, and blocking BK channels by paxilline partly ablated mdivi-1 induced protection. The in vivo experiments showed that mdivi-1 treatment (1 mg/kg) overtly mitigated SCIR injury induced spinal cord edema and neurological dysfunction with no organ-related toxicity in rats. Moreover, mdivi-1 increased the expression of BK channels in spinal cord tissues, and paxilline pretreatment nullified mdivi-1 induced protection after SCIR injury in rats. Thus, mdivi-1 may be an effective therapeutic agent for SCIR injury via activation of BK channels as well as reduction of oxidative stress, mitochondrial dysfunction and neuronal apoptosis. This article is part of a Special Issue entitled SI: Spinal cord injury.

Allicin protects spinal cord neurons from glutamate-induced oxidative stress through regulating the heat shock protein 70/inducible nitric oxide synthase pathway

Allicin, the main biologically active compound derived from garlic, exerts a broad spectrum of pharmacological activities and is considered to have therapeutic potential in many neurological disorders. Using an in vitro spinal cord injury model induced by glutamate treatment, we sought to investigate the neuroprotective effects of allicin in primary cultured spinal cord neurons. We found that allicin treatment significantly attenuated glutamate-induced lactate dehydrogenase (LDH) release, loss of cell viability and apoptotic neuronal death. This protection was associated with reduced oxidative stress, as evidenced by decreased reactive oxygen species (ROS) generation, reduced lipid peroxidation and preservation of antioxidant enzyme activities. The results of western blot analysis showed that allicin decreased the expression of inducible nitric oxide synthase (iNOS), but had no effects on the expression of neuronal NOS (nNOS) following glutamate exposure. Moreover, allicin treatment significantly increased the expression of heat shock protein 70 (HSP70) at both mRNA and protein levels. Knockdown of HSP70 by specific targeted small interfere RNA (siRNA) not only mitigated allicin-induced protective activity, but also partially nullified its effects on the regulation of iNOS. Collectively, these data demonstrate that allicin treatment may be an effective therapeutic strategy for spinal cord injury, and that the potential underlying mechanism involves HSP70/iNOS pathway-mediated inhibition of oxidative stress.

Ginsenoside Rd attenuates mitochondrial permeability transition and cytochrome C release in isolated spinal cord mitochondria: involvement of kinase-mediated pathways

Ginsenoside Rd (Rd), one of the main active ingredients in Panax ginseng, has multifunctional activity via different mechanisms and neuroprotective effects that are exerted probably via its antioxidant or free radical scavenger action. However, the effects of Rd on spinal cord mitochondrial dysfunction and underlying mechanisms are still obscure. In this study, we sought to investigate the in vitro effects of Rd on mitochondrial integrity and redox balance in isolated spinal cord mitochondria. We verified that Ca²⁺ dissipated the membrane potential, provoked mitochondrial swelling and decreased NAD(P)H matrix content, which were all attenuated by Rd pretreatment in a dose-dependent manner. In contrast, Rd was not able to inhibit Ca²⁺ induced mitochondrial hydrogen peroxide generation. The results of Western blot showed that Rd significantly increased the expression of p-Akt and p-ERK, but had no effects on phosphorylation of PKC and p38. In addition, Rd treatment significantly attenuated Ca²⁺ induced cytochrome c release, which was partly reversed by antagonists of Akt and ERK, but not p-38 inhibitor. The effects of bisindolylmaleimide, a PKC inhibitor, on Rd-induced inhibition of cytochrome c release seem to be at the level of its own detrimental activity on mitochondrial function. Furthermore, we also found that pretreatment with Rd in vivo (10 and 50 mg/kg) protected spinal cord mitochondria against Ca²⁺ induced mitochondrial membrane potential dissipation and cytochrome c release. It is concluded that Rd regulate mitochondrial permeability transition pore formation and cytochrome c release through protein kinases dependent mechanism involving activation of intramitochondrial Akt and ERK pathways.

Reproducible porcine model of thoracic aortic aneurysm

BACKGROUND

Thoracic aortic aneurysms (TAAs) develop secondary to abnormal aortic extracellular matrix remodeling, resulting in a weakened and dilated aortic wall that progressed to rupture if left unattended. Currently, no diagnostic/prognostic tests are available for the detection of TAA disease. This is largely driven by the lack of a large animal model, which would permit longitudinal/mechanistic studies. Accordingly, the objective of the present study was to establish a reproducible porcine model of aortic dilatation, which recapitulates the structural and biochemical changes observed during human TAA development.

METHODS AND RESULTS

Descending TAAs were induced in Yorkshire pigs (20-25 kg; n=7) through intra-adventitial injections of collagenase (5 mL, 0.35 mg/mL) and periadventitial application of crystalline CaCl2 (0.5 g). Three weeks after TAA induction, aortas were harvested and tissue was collected for biochemical and histological measurements. A subset of animals underwent MRI preoperatively and at terminal surgery. Results were compared with sham-operated controls (n=6). Three weeks after TAA induction, aortic luminal area increased by 38 ± 13% (P=0.018 versus control). Aortic structural changes included elastic lamellar degradation and decreased collagen content. The protein abundance of matrix metalloproteinases 3, 8, 9, and 12 increased in TAA tissue homogenates, whereas tissue inhibitors of metalloproteinases 1 and 4 decreased.

CONCLUSIONS

These data demonstrate aortic dilatation, aortic medial degeneration, and alterations in matrix metalloproteinase/tissue inhibitors of metalloproteinase abundance, consistent with TAA formation. This study establishes for the first time a large animal model of TAA that recapitulates the hallmarks of human disease and provides a reproducible test bed for examining diagnostic, prognostic, and therapeutic strategies.

Video-atlas of open thoracoabdominal aortic aneurysm repair

Open surgical repair of thoracoabdominal aortic aneurysms has evolved significantly over the last decades thanks to technical improvements, especially in the area of organ protection. However, despite adjunctive strategies, morbidity and mortality rates are still not negligible. Repair of the thoracoabdominal aorta represents a formidable challenge for surgeons, anesthesiologists and patients alike. While operative repair is generally carried out in specialized institutions, knowledge of the state-of-the-art diagnostic, anesthesiologic, surgical and endovascular aspects will certainly be of great value to all physicians involved in the care of these patients at any level. This "How to" video will explain all of these diagnostic, anesthesiologic and surgical aspects in our daily practice.

Hybrid Endovascular Treatment of an Aortic Root and Thoracoabdominal Aneurysm in a High-Risk Patient With Marfan Syndrome

This report describes the hybrid endovascular treatment of an aortic root dilatation and a thoracoabdominal aneurysm in a high-risk patient with Marfan syndrome. A 50-year-old male, in hemodialysis for polycystic kidney and polycystic liver, was referred to our department for aortic root dilatation of 5 cm and a 6.3-cm thoracoabdominal aneurysm . He already underwent surgical repair of abdominal aortic aneurysm 10 years ago, complicated by pseudoaneurysm of the proximal anastomosis that had been treated in another center, with an endoprosthesis. The patient underwent aortic root replacement, aortic valve sparing operation, and rerouting of the superior mesenteric artery and celiac trunk to the ascending aorta. The thoracoabdominal aneurysm was excluded with an endoprosthesis few days after the surgical step. The 12-month computed tomography scan confirmed the complete exclusion of the thoracoabdominal aneurysm.

A shifting approach to management of the thoracic aorta in bicuspid aortic valve

OBJECTIVES

The scientific understanding of aortic dilation associated with bicuspid aortic valve (BAV) has evolved during the past 2 decades, along with improvements in diagnostic technology and surgical management. We aimed to evaluate secular trends and predictors of thoracic aortic surgery among patients with BAV in the United States.

METHODS

We used the 1998-2009 Nationwide Inpatient Sample, an administrative dataset representative of US hospital admissions, to identify hospitalizations for adults aged 18 years or more with BAV and aortic valve or thoracic aortic surgery. Covariates included age, gender, year, aortic dissection, endocarditis, thoracic aortic aneurysm, number of comorbidities, hospital teaching status and region, primary insurance, and concomitant coronary artery bypass surgery.

RESULTS

Between 1998 and 2009, 48,736 ± 3555 patients with BAV underwent aortic valve repair or replacement and 1679 ± 120 patients with BAV underwent isolated thoracic aortic surgery. The overall number of surgeries increased more than 3-fold, from 4556 ± 571 in 1998/1999 to 14,960 ± 2107 in 2008/2009 (P < .0001). The proportion of aortic valve repair or replacement including concomitant thoracic aortic surgery increased from 12.8% ± 1.4% in 1998/1999 to 28.5% ± 1.6% in 2008/2009, which mirrored an increasing proportion of patients with a diagnosis of thoracic aortic aneurysm. Mortality was equivalent for patients undergoing aortic valve repair or replacement with thoracic aortic surgery and those undergoing isolated aortic valve repair or replacement (1.8% ± 0.3% vs 1.5% ± 0.2%; multivariable odds ratio, 1.02; 95% confidence interval, 0.67-1.57), with decreasing mortality over the study period (from 2.5% ± 0.6% in 1998/1999 to 1.5% ± 0.2% in 2008/2009; multivariable odds ratio per 2-year increment, 0.89; 95% confidence interval, 0.81-0.99; P = .03). Total charges for BAV surgical hospitalizations increased more than 7.5-fold from approximately $156 million in 1998 to $1.2 billion in 2009 (inflation-adjusted 2009 dollars).

CONCLUSIONS

There was a marked increase in the use of thoracic aortic surgery among patients with BAV.

Post-conditioning by xenon reduces ischaemia-reperfusion injury of the spinal cord in rats

BACKGROUND

The neuroprotective effects of xenon post-conditioning following spinal cord injury remain unknown. We monitored the effect of xenon post-conditioning on the spinal cord following ischaemia-reperfusion injury and determined its mechanism of action.

METHODS

Spinal cord ischaemia was induced following balloon occlusion of the thoracic aorta in male Sprague-Dawley rats. Rats were divided into three groups (n = 30 in each group). The control group underwent ischaemia-reperfusion injury and immediately inhaled 50% (v/v) nitrogen at the time of reperfusion for 60 min continuously. The xenon-post-conditioning group underwent the same surgical procedure and immediately inhaled 50% (v/v) xenon at the time of reperfusion for 60 min continuously. The sham operation group underwent the same surgical procedure without aortic catheter occlusion and inhaled the same gas as that in control rats. Neurologic function was assessed using the Basso, Beattie, and Bresnahan score at 4, 24, and 48 h after reperfusion. Histological changes were observed using Nissl staining, the ultrastructure of the spinal cord was examined using transmission electron microscopy, and apoptosis was monitored using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labelling.

RESULTS

Compared with the control group, the xenon-post-conditioning group showed improved neurologic outcomes (11.3 ± 1.6 vs. 15.7 ± 3.1, respectively) and had more morphologically normal neurons (6 ± 2 vs. 12 ± 3) at 48 h after reperfusion. Moreover, apoptotic cell death in xenon-treated rats was reduced when compared with control rats (18.29 ± 3.06 vs. 27.34 ± 3.63, P < 0.05, respectively).

CONCLUSIONS

Xenon post-conditioning exerts a neuroprotective effect on the spinal cord following ischaemia-reperfusion injury via its anti-apoptotic role.

Distal aortic perfusion during thoracoabdominal aneurysm repair for prevention of paraplegia

BACKGROUND

During thoracoabdominal aortic aneurysm (TAAA) surgery, decreased spinal cord perfusion can result in neurological deficits such as paraplegia and paraparesis. Distal aortic perfusion, alone or in combination with other adjuncts, may counter the decrease in spinal cord perfusion and hence reduce the risk of spinal cord injury.

OBJECTIVES

To determine the effectiveness of distal aortic perfusion with or without other adjuncts against other adjuncts without use of distal perfusion during TAAA surgery in reducing the risk of developing paraplegia and paraparesis.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Specialised Register (last searched 5 January 2012) and CENTRAL (Issue 4, 2011) were searched for publications describing randomised controlled trials of distal aortic perfusion during thoracoabdominal aortic aneurysm surgery. Reference lists of relevant studies were checked.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical trials of distal aortic perfusion during TAAA repair.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for inclusion by at least two authors, with excluded trials arbitrated by the third author.

MAIN RESULTS

There were no randomised controlled trials identified.

AUTHORS' CONCLUSIONS

Currently, there are no randomised controlled trials to support the role of distal aortic perfusion in TAAA surgery for prevention of neurological injury. However, randomised controlled trials are not always feasible based on ethical grounds. Observational studies suggest that distal aortic perfusion alone or in combination with other adjuncts, that is cerebrospinal fluid (CSF) drainage, reduces the rate of neurologic deficit across all types of TAAA; in particular making a striking difference in the rate of neurologic deficit following type II TAAA repair. In the absence of randomised controlled trials, we recommend a standardised approach to reporting through registry studies to strengthen the evidence base for distal aortic perfusion.

Open repair of extensive thoracoabdominal and thoracic aneurysm: a preliminary single-center experience with femorofemoral distal aortic perfusion with oxygenator and without cerebrospinal fluid drainage

Thoracoabdominal aortic aneurysms (TAAA) and extensive thoracic descending aortic aneurysms (TDA) are not accessible through standard endovascular treatment. Fenestrated and branched endograft technology was developed rapidly without widespread application. The aim of this study was to review our open repair (OR) experience of TAAA and TDA. A total of 28 patients who underwent elective OR of TAAA or TDA between January 2001 and January 2009 were analyzed retrospectively. The mean age of the patients was 65.5 years (three women). The anatomic locations of the aneurysms were as follows: six in thoracic descending aorta and 22 in thoracoabdominal aorta (14 TAAA I, two TAAA II, six TAAA III). TDA (40 patients) available for ordinary endovascular treatment and TAAA IV (35 patients) were excluded from this study. To focus on spinal cord vascularization, 25 patients were submitted for angiography. Three patients suffering from back pain required quick treatment and were excluded from angiographic investigations. Angiography procedures were contributive in 23 patients (92%). Surgical repairs were driven through left thoraco-phreno-laparotomy, with the adjunct of distal aortic perfusion (femorofemoral bypass) including the use of an oxygenator and sequential aortic cross-clamping. Cerebrospinal fluid drainage was not used in this experience. The 30-day mortality rate was 14.3% (four of 28 patients): one multiorgan failure and three pulmonary sepsis. An immediate postoperative paraplegia occurred, affecting a patient with TDA who was previously submitted for infrarenal aorta replacement, despite angiographic identification and revascularization of intercostal artery destined to spinal artery. The 1-year survival rate was 82.1% (23 of 28 patients). In the preliminary experience of this study, OR of extensive TAAA and TDA with distal aortic perfusion and an oxygenator without use of cerebrospinal fluid drainage was associated with a significant perioperative mortality rate (14.2%), a reasonable rate of paraplegia (3%), and 1-year survival rate of 82.1%.

PET/CT and vascular disease: current concepts

Since its introduction in 2001, positron emission tomography associated to computed tomography (PET/CT) has been established as a standard tool in cancer evaluation. Being a multimodality imaging method, it combines in a single session the sensitivity granted by PET for detection of molecular targets within the picomolar range, with an underlying submilimetric resolution inherent to CT, that can precisely localize the PET findings. In this last decade, there have been new insights regarding the pathophysiology of atherosclerosis, particularly about plaque rupture and vascular remodeling. This has increased the interest for research on PET/CT in vascular diseases as a potential new diagnostic tool, since some PET molecular targets could identify diseases before the manifestation of gross anatomic features. In this review, we will describe the current applications of PET/CT in vascular diseases, emphasizing its usefulness in the settings of vasculitis, aneurysms, vascular graft infection, aortic dissection, and atherosclerosis/plaque vulnerability. Although not being properly peripheral vascular conditions, ischemic cardiovascular disease and cerebrovascular disease will be briefly addressed as well, due to their widespread prevalence and importance.

[Spinal cord protection during open and endovascular surgery in thoracic and thoracoabdominal aorta diseases]

In recent decades great advances have been made in surgical procedures for treating thoracic and thoracoabdominal aorta defects. Associated mortality and morbidity rates have dropped considerably, mainly in major reference centers, but nonetheless continue to be significant. The need for new strategies to reduce mortality and morbidity has made endovascular approaches an attractive alternative for high-risk surgical patients. The most feared complications of these procedures include paraparesis and paraplegia, which have devastating consequences on patients' quality of life. We provide an updated review of the pathophysiology of spinal cord ischemia in open and endovascular surgery, as well as perioperative measures designed to protect the spinal cord in both types of procedure.

Total arch replacement with stented elephant trunk technique: a proposed treatment for complicated Stanford type B aortic dissection

OBJECTIVES

The treatment of Stanford type B aortic dissections involving the arch or associated with proximal aortic aneurysms remains a surgical challenge. We report our results with total arch replacement with the stented elephant trunk (SET) procedure for these complicated Stanford type B aortic dissections.

METHODS

Between December 2003 and June 2008, 31 patients were admitted for complicated type B dissection (12 acute, 19 chronic). The mean age at operation was 44.3 +/- 10.6 years (range: 22-68 years). The surgeries were performed by using total arch replacement combined with SET implantation. Enhanced computed tomography (CT) was performed before discharge as well as 3 months and annually to evaluate the condition of the graft and the residual false lumen.

RESULTS

The procedure was successful in all but two patients; two patients died of multiple organ failure following surgery. No paraplegia was observed after surgery. Follow-up was completed in 27 of 29 patients and the mean follow-up period was 18.4 +/- 12.3 months (range: 6-54 months). During follow-up CT scans, thrombus formation was observed in the descending aortic false lumen excluded by the stented graft in most patients. One patient died during follow-up while two patients with Marfan syndrome underwent successful operations for replacement of the remaining descending and abdominal aorta.

CONCLUSION

Total arch replacement with the SET procedure has emerged as a viable option for complicated type B dissections and is associated with low morbidity and mortality. At mid-term follow-up, most patients have either thrombosed or have had no further increase in the false lumen of the descending aorta.

Advances in imaging of the spinal cord vascular supply and its relationship with paraplegia after aortic interventions. A review

INTRODUCTION

Preoperative knowledge of the spinal cord (SC) vasculature could be useful for stratifying and decreasing the risk of perioperative paraplegia after thoracic and thoraco-abdominal aortic surgery. Recent advances in magnetic resonance (MR) and computed tomography (CT) angiography and post-processing techniques have improved this knowledge.

METHODS

A search of MEDLINE/Pubmed and SCOPUS databases identified 1414 pertinent abstracts; 123 full-length manuscripts were screened to identify relevant studies with acceptable design and patient numbers. Forty-three were selected.

RESULTS

SC circulation was studied in 1196 patients to detect the great radicular artery: 522 by MR-angiography and 674 by CT angiography. Detection rates were 67-100% (mean 80.8%) with MR-angiography being 18-100% (mean 72%) with CT angiography. The side and level of the great radicular artery were consistent between the methods. Several authors tried to use the imaging results to guide clinical management.

CONCLUSIONS

Non-invasive imaging of the SC blood supply allows preoperative definition of the vasculature in many, but not all, cases. The impact of these findings on clinical management is potentially beneficial but still uncertain. Further improvements in image acquisition and post-processing techniques are needed. Future studies need to be large enough to compensate for inter-individual variability in SC vasculature in health and disease; however, even a partial reduction of paraplegia rate offers a formidable motivation for further research in this area.

Differential responses of porcine anterior spinal and middle cerebral arteries to carbon dioxide and pH

OBJECTIVE

Dysfunction of the anterior spinal arteries (ASAs) may induce paresis or paraplegia after thoracoabdominal aortic aneurysm or spine surgery. However, there have been no reports of the effects of CO2 and pH on ASAs. Information on these effects on ASAs might contribute to the perioperative management or critical care of spinal cord function. Thus, we investigated the effects of CO2 and pH on the vasomotor tone of ASAs and the third branch of the middle cerebral artery (bMCA).

DESIGN

Prospective study of the effects of CO2 and pH on vasomotor response of porcine ASA and bMCA in vitro.

SETTING

University laboratories.

SUBJECTS

Porcine heads and spinal cords obtained from a slaughterhouse.

INTERVENTION

ASAs and bMCAs were isolated, and changes in the intraluminal region of these pressurized arteries ( approximately 80 mm Hg) were observed for 30 minutes after perfusion with a solution saturated with various concentrations of CO2 and pH.

MEASUREMENTS AND MAIN RESULTS

Respiratory acidosis (pH/Pco2 approximately 7.10-7.15/ approximately 60-80 mm Hg) constricted the ASAs, followed by a partial but gradual decrease in tone, whereas the bMCAs were exclusively dilated. The respiratory alkalosis (pH/Pco2 approximately 7.60/ approximately 20 mm Hg) did not influence ASA tone. Vasoconstriction of the ASAs induced by respiratory acidosis was abolished by removal of the endothelium, but not by N-nitro-L-arginine (1 microM). Respiratory acidosis dilated the ASAs in all preparations treated with ONO-3708 (1 microM), a specific thromboxane A2 receptor antagonist, and OKY-046 (1 microM), a specific thromboxane synthase inhibitor. Metabolic acidosis (pH/Pco2 approximately 7.10/ approximately 40 mm Hg) caused dilation of both bMCAs and ASAs, which was abolished by glibenclamide (1 microM).

CONCLUSIONS

CO2-induced endothelium-dependent constriction in porcine ASAs through releasing thromboxane A2-like substance(s). Thus, hypercarbia might not be favorable for the perioperative or critical care management of spinal cord function during thoracoabdominal aortic aneurysm and spine surgery.

Neurologic outcomes from high risk descending thoracic and thoracoabdominal aortic operations in the era of endovascular repair

INTRODUCTION

Spinal cord ischemia and stroke are recognized complications of descending thoracic (DTA) and thoracoabdominal aortic (TAA) operations. However, there are limited data available on outcomes since the advent of thoracic endovascular aortic repair (TEVAR).

METHODS

We reviewed charts from consecutive patients who underwent open DTA and TAA operations, excluding type IV repair, from January, 2000 through April, 2005.

RESULTS

A total of 224 open DTA and TAA operations were included in the analysis. During this period 108 additional patients received TEVAR, accounting for 66% of all DTA repairs. Among the 224 patients who underwent open surgery, 63 patients (28%) developed spinal ischemia postprocedure, 13 (6%) had a stroke, and 9 (4%) had both. The 30 day in-hospital mortality was 18%. Neurologic complications were strongly associated with mortality: 64% of patients with stroke died compared to 17% without (P < 0.001) and 39% of patients with spinal ischemia died compared to 14% without (P < 0.001). At discharge, 29% had a poor outcome from surgery, defined as death or moderate-to-severe neurologic disability. A multivariable logistic regression incorporating characteristics known prior to surgery resulted in a score to stratify risk of poor outcome by giving one point each for age > or =60, history of cerebrovascular disease, Crawford extent II or III repair, and acute rupture. Patients with score > or =3 had an estimated 60% risk for poor outcome, while those with score < or =1 had an estimated risk of 7-11%.

CONCLUSIONS

Ischemic neurologic complications were frequent and strongly associated with poor outcomes after open DTA and TAA repair among patients not eligible for TEVAR. Risk of death or neurologic disability can be estimated based on factors known prior to surgery.

Transforming growth factor-beta signaling in thoracic aortic aneurysm development: a paradox in pathogenesis

Thoracic aortic aneurysms (TAAs) are potentially devastating, and due to their asymptomatic behavior, pose a serious health risk characterized by the lack of medical treatment options and high rates of surgical morbidity and mortality. Independent of the inciting stimuli (biochemical/mechanical), TAA development proceeds by a multifactorial process influenced by both cellular and extracellular mechanisms, resulting in alterations of the structure and composition of the vascular extracellular matrix (ECM). While the role of enhanced ECM proteolysis in TAA formation remains undisputed, little attention has been focused on the upstream signaling events that drive the remodeling process. Recent evidence highlighting the dysregulation of transforming growth factor-beta (TGF-beta) signaling in ascending TAAs from Marfan syndrome patients has stimulated an interest in this intracellular signaling pathway. However, paradoxical discoveries have implicated both enhanced TGF-beta signaling and loss of function TGF-beta receptor mutations, in aneurysm formation; obfuscating a clear functional role for TGF-beta in aneurysm development. In an effort to elucidate this subject, TGF-beta signaling and its role in vascular remodeling and pathology will be reviewed, with the aim of identifying potential mechanisms of how TGF-beta signaling may contribute to the formation and progression of TAA.