Prognosis after non-surgical therapy for acute type A aortic dissection

BACKGROUND

Immediate surgery to save life is the recommended treatment for Stanford type A acute aortic dissection (AAAD).

METHOD

The present study comprised 35 patients admitted with AAAD who were considered inappropriate candidates for surgery or declined surgery. The mean age was 84.5 ± 9.6 years. Eight patients who were considered inappropriate candidates for surgery due to severe stroke in 2 patients or hemodynamic instability in 6. Twenty-seven patients aged 88.0 ± 5.9 years who declined surgery, predominantly due to advanced age.

RESULTS

The overall in-hospital mortality was 51.4%. Mortality among patients that declined surgery or were considered inappropriate candidates for surgery were 37% and 100%, respectively. Causes of death among patients that declined surgery were cardiac tamponade in 6 and aortic rupture in 4. Mid-term survival among patients who refuse surgery, including in-hospital death, were 51.6 ± 10% and 34.5 ± 10%, on the other hand, Mid-term survival in hospital survivors were 81.9 ± 9% and 54.8 ± 14%. The causes of death among the discharged patients were senility in three, malignant tumor in two, pneumonia, aortic rupture, and unknown cause in one each.

CONCLUSIONS

Mortality from AAAD is 51.4%, including inappropriate candidates for surgery. When patients were evaluated as suitable candidates for surgical intervention but subsequently refused the surgical procedure, in-hospital mortality was 37%. Long-term survival of hospital survivor was acceptable. These data can be a benchmark for patient and patient's family to select medical therapy for AAAD in consideration with the patient's will.

The open-first strategy is acceptable for ruptured abdominal aortic aneurysm even in the endovascular era

PURPOSE

To examine the surgical findings of ruptured abdominal aortic aneurysm (RAAA) based on the open-first strategy in the last decade, and to analyze the predictors of in-hospital mortality for RAAA in the endovascular era.

METHODS

The subjects of this retrospective study were 116 patients who underwent RAAA repair, for whom sufficient data were available [25% female, median age 76 (70-85) years]. Sixteen (13.8%) patients were managed with endovascular aneurysm repair (EVAR) and 100 patients (86.2%) were managed with open surgical repair (OSR).

RESULTS

Univariate analysis identified base excess (BE) (odds ratio [OR] 0.88; 95% confidence interval [CI] 0.79-0.96; p = 0.006), and preoperative cardiopulmonary arrest (CPA) [OR] 15.4; 95% [CI] 1.30-181; p = 0.030), BE (OR 0.88; 95% CI 0.79-0.96; p = 0.006), shock index (OR 2.44; 95% CI 1.01-5.94; p = 0.050), lactic acid (Lac) (OR 1.18; 95% CI 1.02-1.36; p = 0.026), and blood sugar (BS) > 215 (OR 3.46; 95% CI 1.10-10.9; p = 0.034) as positive predictors of hospital mortality.

CONCLUSIONS

The findings of this study suggest that a first-line strategy of OSR for ruptured AAAs is acceptable. Poor preoperative conditions, including a high shock index, CPA, low BE, high Lac, and a BS level > 215 mg/dl, were identified as predictors of hospital mortality, rather than the procedures themselves.

Covering the intercostal artery branching of the Adamkiewicz artery during endovascular aortic repair increases the risk of spinal cord ischemia

Objectives

This study aimed to determine the relationship between covering the intercostal artery branching of the Adamkiewicz artery (ICA-AKA) and spinal cord ischemia (SCI) during thoracic endovascular aortic repair (TEVAR).

Methods

Patients who underwent TEVAR from 2008 to 2022 were enrolled. Stent grafts covered the ICA-AKA in 108 patients (covered AKA group) and stent grafts didn't cover the ICA-AKA in 114 patients (uncovered AKA group). The characteristics of 58 patients from each group were matched based on propensity scores.

Results

No significant differences in SCI rates were detected between the covered AKA (10%; 11/108) and uncovered AKA (3.5%; 4/114) groups (P = .061). Shaggy aorta (odds ratio [OR], 5.16; 95% confidence interval [CI], 1.74-15.3, P = .003), iliac artery access (OR, 6.81; 95% CI, 2.22-20.9, P = .001), and procedural time (OR, 1.01; 95% CI, 1.00-1.02, P = .003) were risk factors for SCI in the entire cohort. Although covering the ICA-AKA (OR, 2.60; 95% CI, 0.86-7.88, P = .058) was not a significant risk factor, shaggy aorta (OR, 8.15; 95% CI, 2.07-32.1, P = .003), iliac artery access (OR, 9.09; 95% CI, 2.22-37.2, P = .002), and procedural time (OR, 1.01; 95% CI, 1.01-1.02, P = .008) were risk factors for SCI in the covered AKA group. No significant risk factors were detected in the uncovered AKA group.

Conclusions

Covering the ICA-AKA was not an independent risk for SCI in TEVAR. However, covering the ICA-AKA was indirectly associated with the risk of SCI in patients with shaggy aorta, iliac access, and procedural time.

Lower-profile stent graft reduces the risk of embolism during thoracic endovascular aortic repair in shaggy aorta

OBJECTIVES

This study aimed to reveal the association between lower-profile stent graft and embolism during thoracic endovascular aortic repair for non-dissecting distal arch and descending thoracic aortic aneurysm.

METHODS

This study reviewed data of 35 patients who underwent thoracic endovascular aortic repair with lower-profile stent graft (27 males; age: 77 ± 9.2 years) and 312 who underwent thoracic endovascular aortic repair with conventional-sized stent graft (247 males; age: 77 ± 7.4 years) from 2009 to 2021.

RESULTS

The rate of total embolic events was significantly lower in lower-profile stent graft group (0/35 [0%]) than the conventional-sized stent graft group (34/312 [11.2%]) (p = 0.035). Shaggy aorta (odds ratio: 5.220; p < 0.001) were identified as positive embolic event predictors. The rate of total embolic events in 68 patients with shaggy aorta (12 in lower-profile stent graft/56 in conventional-sized stent graft) was significantly lower in the lower-profile stent graft group (0/12 [0%]) than the conventional-sized stent graft group (19/56 [34%]) (p = 0.015). The rate of total embolic events in 279 patients with the non-shaggy aorta (23 in lower-profile stent graft/256 in conventional-sized stent graft) reveals no difference between the two groups (0 [0%]/16 [6.3%]) (p = 0.377).

CONCLUSIONS

Lower-profile stent graft usage could reduce embolism in thoracic endovascular aortic repair, and the difference was more pronounced in patients with the shaggy aorta. Lower-profile stent graft might be beneficial in preventing embolism in thoracic endovascular aortic repair for patients with a shaggy aorta.

Role of initial medical treatment and effectiveness of thoracic endovascular aortic repair for acute type a aortic dissection with thrombosed false lumen

OBJECTIVES

The optimal treatment for acute type A aortic dissection (AAAD) with thrombosed false lumen (T-FL) of the ascending aorta remains controversial. This study aimed to the evaluate clinical outcomes of initial medical treatment (IMT) and the effectiveness of thoracic endovascular aortic repair (TEVAR) for AAAD with T-FL.

METHODS

We retrospectively analysed 60 AAAD with T-FL patients. Emergent aortic repair was performed in 33 patients and IMT was selected in 27 uncomplicated patients with ascending aortic diameter < 50 mm and ascending T-FL thickness ≤ 10 mm.

RESULTS

Among the 27 patients who received IMT, 14 had intramural haematoma at admission; however, new ulcer-like projections appeared in 7 (50%) during hospitalization. Before discharge, 12 (44%) were treated with only medical treatment and 15 (56%) required delayed aortic repair including TEVAR in 8 and open repair in 7. The median interval from onset to delayed repair was 9 days and significantly more patients received TEVAR compared to those receiving emergent repair (53% vs 21%; P = 0.043). Between TEVAR (n = 15) and open repair (n = 33), one (7%) 30-day mortality occurred in TEVAR, whereas no in-hospital mortality occurred in open repair. During the median follow-up time of 24.8 months, no aorta-related death was observed and there were no statistically significant differences in the freedom rate from aortic events (TEVAR: 92.8%/3 years vs open repair: 88.4%/3 years; P = 0.871).

CONCLUSIONS

Our management with a combination of emergent aortic repair, IMT, and delayed aortic repair for AAAD with T-FL achieved favourable clinical outcomes. In the selected Japanese patients, IMT with repeated MDCT could detect a new intimal tear which could be closed by TEVAR in some cases and TEVAR for this pathology resulted in acceptable early and mid-term outcomes. Further investigations are required to validate the safety and efficacy of this management.

Surgical outcomes of thoracic endovascular aortic repair for retrograde Stanford type A dissection

OBJECTIVES

The optimal indications and contra-indications for thoracic endovascular aortic repair of retrograde acute Stanford type A aortic dissection are not well known. The aim of this study was to determine the outcomes of thoracic endovascular aortic repair for retrograde acute Stanford type A aortic dissection at our institutions and discuss optimal indications.

METHODS

The medical records of 359 patients admitted to our institution for acute Stanford type A aortic dissection between December 2016 and December 2022 were reviewed, and 83 patients were finally diagnosed with retrograde acute Stanford type A aortic dissection. We selected thoracic endovascular aortic repair as an alternative, considering the anatomy of aortic dissection and the risk to patients undergoing open surgery.

RESULTS

Nineteen patients underwent thoracic endovascular aortic repair for retrograde Stanford type A aortic dissection. No in-hospital mortality and neurological complication occurred. A Type Ia endoleak was detected in one patient. All other primary entries were successfully closed. All dissection-related complications, such as cardiac tamponade, malperfusion in distal to the primary entry, and abdominal aortic rupture, were resolved. One patient required open conversion for intimal injury at the proximal edge of the stent graft; all other ascending false lumens were completely thrombosed and contracted at discharge. During the follow-up period, no aortic-related deaths or aortic events proximal to the stent graft occurred.

CONCLUSION

The indications for thoracic endovascular aortic repair were expanded to low-risk and emergent cases at our institution, and the early- and mid-term outcomes of thoracic endovascular aortic repair for retrograde Stanford type A aortic dissection were acceptable. Further long-term follow-up is required.

Differences of mid-term outcomes in debranching thoracic endovascular aortic repair between zone 0 and zone 1-2 landing

OBJECTIVE

Debranching thoracic endovascular aortic repair (d-TEVAR) for zone 0 landing (Z0-TEVAR) remained challenging in aortic arch aneurysms. This study aimed to compare the mid-term outcomes between Z0-TEVAR and Z1/2-TEVAR to assess the appropriateness of Z0-TEVAR as the first-line therapy for aortic arch aneurysms in high-risk patients.

METHODS

Medical records of 200 patients who underwent d-TEVAR from 2007 to 2019 were retrospectively reviewed. Of these, 40 patients who underwent Z0-TEVAR (70% males; the median age of 82 years) and 160 Z1/2-TEVAR (78% males; the median age of 77 years) were compared. In each group, 39 patients were matched using propensity scores (PS) to adjust for differences in patient backgrounds.

RESULTS

Freedom from all-cause mortality (p < 0.001), aorta-related mortality (p < 0.001), and stroke (p = 0.001) were significantly lower in Z0-TEVAR than in Z1/2-TEVAR. Freedom from reintervention was similar between the two groups (p = 0.326). Type A dissection post-TEVAR was observed in 3 (7.5%) of Z0-TEVAR, but none in Z1/2-TEVAR (p = 0.006). Pneumonia was also more frequent in Z0-TEVAR (n = 8, 30%) than Z1/2-TEVAR (n = 4, 2.5%) (p < 0.001). PS matching also yielded worse outcomes (all-cause mortality, p = 0.017; aorta-related mortality, p = 0.046; and stroke, p = 0.027) in Z0-TEVAR than Z1/2-TEVAR.

CONCLUSIONS

Higher mid-term mortality and stroke rates after Z0-TEVAR were confirmed by PS matching. Z0-TEVAR would be an alternative for high-risk patients with arch aneurysms requiring zone 0 landing but not a reliable method.

Aggressive use of prophylactic cerebrospinal fluid drainage to prevent spinal cord ischemia during thoracic endovascular aortic repair is not supportive

OBJECTIVE

We investigated whether prophylactic preoperative cerebrospinal fluid drainage was effective in preventing spinal cord ischaemia during thoracic endovascular aortic repair for degenerative descending thoracic aortic aneurysm, excluding dissecting aneurysms.

METHODS

We retrospectively reviewed medical records of the patients who underwent thoracic endovascular aortic repair with proximal landing zones 3 and 4 for between 2009 and 2020.

RESULTS

Eighty-nine patients with preemptive cerebrospinal fluid drainage (68 men; median [range] age, 76.0 [71.0-81.0] years) and 115 patients without cerebrospinal fluid drainage (89 men; median [range] age, 77.0 [74.0-81.5] years) were included in this study. Among them, 59 from each group were matched based on propensity scores to regulate for differences in backgrounds. The incidence rate of spinal cord ischaemia was similar: 8/89 (9.0%) in the cerebrospinal fluid drainage group and 6/115 (5.2%) in the non-cerebrospinal fluid drainage group (p = 0.403). Shaggy aorta (odds ratio, 5.13; p = 0.004) and iliac artery access (odds ratio, 5.04; p = 0.005) were identified as positive predictors of spinal cord ischaemia. Other clinically important confounders included Adamkiewicz artery coverage (odds ratio, 2.53; p = 0.108) and extensive stent graft coverage (>8 vertebrae) (odds ratio, 1.41; p = 0.541) were not statistically significant. Propensity scores matching yielded similar incidence of spinal cord ischaemia: 4/59 (6.8%) in the cerebrospinal fluid drainage group and 3/59 (5.1%) in the non-cerebrospinal fluid drainage group (p = 0.697).

CONCLUSIONS

Aggressive use of prophylactic cerebrospinal fluid drainage was not supportive in patients without complex risks of spinal cord ischaemia.

The Fate of Down-stream Aorta after Total Arch Replacement

OBJECTIVES

The aim of this study was to evaluate the fate of down-stream aorta following total arch replacement.

METHODS

Between October 1999 and March 2018, 740 patients underwent total arch replacement. After excluding connective tissue disease, previous descending or thoracoabdominal aortic surgery, patients without adequate preoperative images, or operative mortality, late outcomes consisting of additional surgery for distal dilation and distal aortic events were evaluated in 623 survivors (240 aortic dissections, including 139 patients with acute dissection and 383 with non-dissection aneurysm). The mean follow-up was 5.0 ± 4.0 years.

RESULTS

The mean preoperative maximum diameter of descending aorta was 36.9 ± 8.0 mm. Elephant trunk was inserted in 232 patients, including 183 patients with aortic dissection. Freedom from additional surgery for distal dilation was 88.5% at 5 years and 80.2% at 10 years. Freedom from distal aortic events was 81.9% at 5 years and 70.5% at 10 years. Multivariable regression analysis demonstrated that a preoperative diameter of descending aorta was a significant risk factor for unfavorable distal aortic events. Computed tomography evaluation demonstrated significant increase in descending aortic diameter over time (p < 0.001). Positive aortic remodeling was observed in the proximal descending (p < 0.001) to mid descending (p < 0.001) aorta exclusively in patients with acute aortic dissection.

CONCLUSIONS

The descending aortic diameter increased significantly after total arch replacement, particularly in distal descending aorta. Preoperative descending aortic diameter portended a significant risk for unfavorable distal aortic events.

Novel brain computed tomography perfusion for cerebral malperfusion secondary to acute type A aortic dissection

OBJECTIVES

The management of acute type A aortic dissection with malperfusion syndrome remains challenging. To evaluate preoperative condition, symptoms might be subjective and objective evaluation of cerebral artery has not yet been established. For quantitative evaluation, this study focused on brain computed tomography perfusion (CTP), which has been recommended by several guidelines of acute ischaemic stroke.

METHODS

In the last 2 years, 147 patients hospitalized due to acute type A aortic dissection were retrospectively reviewed. Among the 23 (16%) patients with cerebral malperfusion, 14 who underwent brain CTP (6 preoperative and 8 postoperative) were enrolled. CTP parameters, including regional blood flow and time to maximum, were automatically computed using RApid processing of Perfusion and Diffusion software. The median duration from the onset to hospital arrival was 129 (31-659) min.

RESULTS

Among the 6 patients who underwent preoperative CTP, 4 with salvageable ischaemic lesion (penumbra: 8-735 ml) without massive irreversible ischaemic lesion (ischaemic core: 0-31 ml) achieved acceptable neurological outcomes after emergency aortic replacement regardless of preoperative neurological severity. In contrast, 2 patients with an ischaemic core of >50 ml (73, 51 ml) fell into a vegetative state or neurological death due to intracranial haemorrhage. CTP parameters guided postoperative blood pressure augmentation without additional supra-aortic vessel intervention in the 8 patients who underwent postoperative CTP, among whom 6 achieved normal neurological function regardless of common carotid true lumen stenosis severity.

CONCLUSIONS

CTP was able to detect irreversible ischaemic core, guide critical decisions in preoperative patients and aid in determining the blood pressure augmentation for postoperative management focusing on residual brain ischaemia.

The blood sugar level can predict preoperative shock in patients with a ruptured abdominal aortic aneurysm even when the patient's condition appears stable

PURPOSE

This observational retrospective study aimed to identify preoperative blood test data capable of predicting preoperative shock in ruptured abdominal aortic aneurysm (rAAA).

METHODS

A total of 104 patients who underwent surgery for rAAA between 2007 and 2018 were reviewed. Preoperative shock, defined as a shock index (heart rate/blood pressure) exceeding 1.5 or a maximum blood pressure < 80 mmHg, was observed in 44 patients (42%).

RESULTS

Blood sugar (BS) (odds ratio [OR] 1.02; p < 0.001), C-reactive protein (CRP) (OR 0.57; p = 0.005), and hemoglobin (OR 0.60; p = 0.001) levels were identified as independent positive predictors of preoperative shock, and a BS level ≥ 300 mg/dl (OR 13.2; 95% CI 3.56-48.6; p < 0.001) was identified as a positive predictor of preoperative shock. The receiver operating characteristics curve analysis for BS showed that the area under the curve for the predicted probabilities was 0.84, and at a cut-off value of 215 mg/dl, the sensitivity of minimum BS for predicting preoperative shock was 86% with a specificity of 79%.

CONCLUSIONS

The BS level is as an independent predictor of preoperative shock in patients with rAAA. Patients with preoperative BS levels ≥ 300 mg/dl have an extremely high risk of preoperative shock.

Endovascular and Endoscopic Treatment for Primary Aortoduodenal Fistula: A Case Report

Primary aortoduodenal fistula (ADF) is a relatively rare and morbid diagnosis. A 91-year-old man who developed hematemesis and melena was transferred from a community hospital with the diagnosis of a ruptured abdominal aortic aneurysm (AAA). Computed tomography revealed an irregular-shaped AAA with cavities enhanced near the duodenum, with suspected ADF. The patient was initially treated with emergency endovascular aneurysm repair. Duodenoscopy showed defects of the mucosa. ADF was diagnosed, and fistulas were closed with endoscopic clipping. This case highlights the success of ADF endovascular repair.

Impact of the coronavirus disease 2019 (COVID-19) pandemic on the care of patients with acute and chronic aortic conditions

OBJECTIVES

To evaluate the impact of the coronavirus disease 2019 (COVID-19) pandemic on acute and elective thoracic and abdominal aortic procedures.

METHODS

Forty departments shared their data on acute and elective thoracic and abdominal aortic procedures between January and May 2020 and January and May 2019 in Europe, Asia and the USA. Admission rates as well as delay from onset of symptoms to referral were compared.

RESULTS

No differences in the number of acute thoracic and abdominal aortic procedures were observed between 2020 and the reference period in 2019 [incidence rates ratio (IRR): 0.96, confidence interval (CI) 0.89-1.04; P = 0.39]. Also, no difference in the time interval from acute onset of symptoms to referral was recorded (<12 h 32% vs > 12 h 68% in 2020, < 12 h 34% vs > 12 h 66% in 2019 P = 0.29). Conversely, a decline of 35% in elective procedures was seen (IRR: 0.81, CI 0.76-0.87; P < 0.001) with substantial differences between countries and the most pronounced decline in Italy (-40%, P < 0.001). Interestingly, in Switzerland, an increase in the number of elective cases was observed (+35%, P = 0.02).

CONCLUSIONS

There was no change in the number of acute thoracic and abdominal aortic cases and procedures during the initial wave of the COVID-19 pandemic, whereas the case load of elective operations and procedures decreased significantly. Patients with acute aortic syndromes presented despite COVID-19 and were managed according to current guidelines. Further analysis is required to prove that deferral of elective cases had no impact on premature mortality.

Open anatomical repair for primary coarctation of the aorta in adults

OBJECTIVES

Although endovascular repair has become an alternative treatment for coarctation of the aorta (CoA) in adults, open repair provides concomitant repair of other cardiac complications, including post-stenotic aneurysm, ascending aortic aneurysm, and intracardiac diseases. We evaluated open anatomical repair for CoA repair in adults.

METHODS

Eleven patients (6 men, age range 21-63 years) underwent primary CoA repair. Complicating conditions included post-stenotic aortic aneurysm in the descending aorta in 5 patients (45.5%) and ascending aortic aneurysm in 3 (27.3%). Two patients (18.2%) had a bicuspid aortic valve, and one (9.1%) had a quadricuspid aortic valve. Ventricular septal defect was detected in 1 patient (9.1%). Eight patients (72.7%) underwent descending aorta replacement through a left thoracotomy, comprising partial cardiopulmonary bypass in 4 and deep hypothermic circulatory arrest in 4. Of those, the left subclavian artery was reconstructed in 4 patients. The remaining 3 patients (27.3%) underwent total arch replacement, through a median sternotomy in 1 and using a combination of median sternotomy and thoracotomy in 2.

RESULTS

No in-hospital mortality was observed. No spinal cord ischemia or neurological events were encountered, but 1 patient (9.1%) who underwent CoA repair via median sternotomy and thoracotomy required prolonged ventilatory support for more than 48 h. During the follow-up of 90 months (interquartile range 65-124 months), no patient died or required reintervention for the repaired segment.

CONCLUSIONS

CoA in adults could be anatomically repaired with graft replacement both through the median sternotomy, the left thoracotomy, and the combination of both approaches, according to the complicated aortic or intracardiac lesions.

The impact of vascularized tissue flap coverage on aortic graft infection with and without infected graft excision

OBJECTIVES

Aortic graft infection (AGI) is a serious condition associated with a high mortality rate. However, optimal surgical options have not been identified. Therefore, we retrospectively reviewed AGI cases, including those in the thoracic and abdominal regions, with or without fistula formation, to investigate the various options for better outcomes.

METHODS

We reviewed 50 patients who underwent surgical interventions for AGI out of 97 patients with arterial infective disease. The mean patient age was 67 ± 17 years. Fourteen patients (28%) had a fistula with the gastrointestinal tract or lung. A combination of graft excision and vascularized tissue flap coverage was performed in 25 cases (50%). Tissue flap alone, graft excision alone and cleansing alone were performed in 9 (18%), 10 (20%), and 6 cases (12%), respectively.

RESULTS

Total in-hospital mortality rate was 32% (n = 16). In-hospital mortalities in patients with and without fistulas were 43% (6/14) and 28% (10/36), respectively (P = 0.33). Subgroup analysis among patients without fistula demonstrated that the in-hospital mortality rate of the patients with vascularized tissue flap (3/21, 14%) was significantly lower than that of the patients without vascularized tissue flap (7/14, 50%, P = 0.026). Overall 1- and 5-year survival rates were 66% and 46%, respectively. In multivariable analysis, an independent factor associated with in-hospital mortality was vascularized tissue flap (odds ratio 0.20, P = 0.024).

CONCLUSIONS

Vascularized tissue flaps could provide better outcomes for AGI. Graft preservation with vascularized tissue flaps could be a useful option for AGI without fistula.

Severe intraluminal atheroma and iliac artery access affect spinal cord ischemia after thoracic endovascular aortic repair for degenerative descending aortic aneurysm

OBJECTIVES

This study aimed to reveal additional factors potentially contributing to the multifactorial ethiopathogenesis of spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR) for descending thoracic aortic aneurysm (TAA).

METHODS

The medical records of 293 patients who underwent TEVAR without debranching procedures for descending TAA between 2011 and 2018 were retrospectively reviewed. We excluded the following cases from the study: 72 patients with aortic dissection; 15 with rupture; 14 with anastomotic pseudoaneurysm; 22 with re-TEVAR; 34 without evaluation of the artery of Adamkiewicz (AKA). Sufficient data were available for 136 patients (79% men; mean age of 76 ± 7.4 years). We conducted univariable and multivariable analyzes using the logistic regression analysis to assess the relationship between pre-/intraoperative factors and postoperative SCI.

RESULTS

SCI was observed in nine patients (6.8%). Severe intraluminal atheroma [odds ratio (OR), 6.23; p = 0.014] and iliac artery access (OR 4.65; p = 0.043) were identified as the positive predictors of SCI by univariable analysis. Risk factors of SCI were determined additionally as follows: coverage of the intercostal artery branching AKA (ICA-AKA) (OR 4.89; p = 0.054); coverage of the ICA-AKA combined with iliac access (OR 10.1; p = 0.002); that combined with severe intraluminal atheroma (OR 13.7; p = 0.001).

CONCLUSION

Severe intraluminal atheroma and iliac artery access were the independent predicting factors of SCI after TEVAR for degenerative descending TAA. In patients with complicated aortoiliofemoral access route, coverage of the ICA-AKA is associated with the risk of SCI.

Preoperative renal function affects outcomes of surgery for aortic arch aneurysm in the elderly

OBJECTIVES

This study aimed to determine the optimal surgical procedure for arch aneurysm in the elderly based on preoperative comorbidities, especially focusing on renal function.

METHODS

The medical records of 374 patients who experienced arch surgery between 2008 and 2019 were reviewed. Among the 374 patients, 92 who underwent total arch replacement (TAR) were assigned to the TAR group and the remaining 152 who underwent debranching thoracic endovascular aortic repair (DTEVAR) were assigned to the DTEVAR group.

RESULTS

Chronic kidney disease (CKD) was an independent risk factor of mortality (hazard ratio, 2.85; p = 0.029) in the TAR group but not in the DTEVAR. In the Grade I/II category CKD (estimated glomerular filtration rate (eGFR) > 60 mL/min), freedom from all-cause mortality was significantly higher in the TAR group than in the DTEVAR group (p = 0.0155, log-rank). Freedom from all-cause mortality was comparable between the two groups in the Grade IIIa CKD (eGFR, 45-60) (p = 0.584, log-lank), Grade IIIb (eGFR, 30-45) (p = 0.822), and Grade IV/V (eGFR < 30) (p = 0.548).

CONCLUSION

In elderly patients who underwent TAR, CKD was the independent risk factor of the mortality, but not in the patients who underwent debranching TEVAR. Conversion of surgical strategy from TAR to debranching TEVAR in the treatment of aortic arch aneurysms in the elderly with CKD below Grade IIIa is acceptable considering that less-invasiveness. While, in the elderly with Grade I/II CKD, TAR still remains as a primary choice for the arch repair for better mid-term survival.

Right ventricular outflow tract obstruction caused by sinus of Valsalva aneurysm

Right ventricular outflow tract (RVOT) obstruction caused by sinus of Valsalva aneurysm is a rare observation. We describe a successful case of valve-sparing root replacement using reimplantation technique for RVOT obstruction by a large right coronary sinus of Valsalva aneurysm in a 76-year-old man. In the pathological examination, the elastic fibers of the medial layer were defective not only in the wall of the aneurysmal Valsalva sinus but also in the remaining two sinus walls. Our experience illustrated that valve-sparing root replacement can be an effective procedure in such a case.

The fate of the downstream aorta after open aortic repair for acute DeBakey type I aortic dissection: total arch replacement with elephant trunk technique versus non-total arch replacement†

OBJECTIVES

The aim of this study was to evaluate the fate of the downstream aorta following open aortic repair for acute DeBakey type I aortic dissection comparing total arch replacement (TAR) with the elephant trunk (ET) technique versus non-total arch replacement (non-TAR).

METHODS

From October 1999 to December 2016, 267 patients underwent open repair for acute DeBakey type I aortic dissection. A tear-oriented strategy was mainly used to determine the extent of graft replacement. Hospital mortality was 10.0% (12/120 patients) in the TAR group and 17.0% (25/147 patients) in the non-TAR group (P = 0.070). Late outcomes were compared in 230 hospital survivors (TAR: n = 108 and non-TAR: n = 122). Mean follow-up was 6.5 ± 4.6 years. The aortic diameters were measured at 4 levels, across 6 time points using computed tomography.

RESULTS

Freedom from additional aortic surgery for distal dilation was significantly better in the TAR group than the non-TAR group (TAR: 97.5 ± 1.8% at 5 years and non-TAR: 88.2 ± 3.4% at 5 years, P = 0.045). Freedom from a distal aortic event was also significantly better in the TAR group compared with the non-TAR group (TAR: 97.2 ± 1.6% at 5 years and non-TAR: 80.7 ± 4.2% at 5 years, P = 0.013). In the non-TAR group, the aortic arch diameter significantly increased (P < 0.001). Significant aortic remodelling occurred at the proximal descending aorta in the TAR with ET group (P < 0.001).

CONCLUSIONS

The TAR with ET reduced the need for additional distal aortic repair compared to non-TAR. TAR with ET prevented unfavourable aortic growth in both the aortic arch and the proximal descending aorta.

Preoperative Neck Angulation is Associated with Aneurysm Sac Growth Due to Persistent Type Ia Endoleak after Endovascular Abdominal Aortic Aneurysm Repair

Objective: This study aims to determine how instructions for use affect the occurrence of aneurysm sac growth and endoleaks after an endovascular aneurysm repair (EVAR).

Materials and Methods: We reviewed 302 patients who underwent EVAR for abdominal aortic aneurysm between 2007 and 2013, and we were able to enroll 159 patients (74% men, mean age 78±7 years) with adequate data (mean follow-up; 48±20 months).

Results: The angle of the proximal landing zone (LZ) (hazard ratio: 1.02, 95% confidence interval: 1.00–1.03, p=0.01) was recognized as an independent risk factor of sac growth (≥5 mm). The receiver operating characteristics curve (area under the curve: 0.72) showed a cutoff value of 47° of the minimum angle of the proximal LZ to predict sac growth. Freedom rates for persistent type Ia endoleaks were also found to be lower in the angulated group than those in the other groups (p=0.0095, log-rank).

Conclusion: The angle of the proximal LZ was identified as an independent risk factor for sac growth post-EVAR. The incidence of persistent type Ia endoleaks was significantly higher in the angulated group.

Synchrotron Radiation-based X-ray phase-contrast imaging of the aortic walls in acute aortic dissection

Objective

Synchrotron radiation-based X-ray phase-contrast tomography (XPCT) imaging is an innovative modality for the quantitative analysis of three-dimensional morphology. XPCT has been used in this study to evaluate ascending aorta specimens from patients with acute type A aortic dissection (ATAAD) and to analyze the morphologic structure of the aortic wall in patients with this condition.

Methods

Aortic specimens from 12 patients were obtained during repairs for ATAAD and were fixed with formalin. Five patients had Marfan syndrome (MFS), and seven did not. In addition, six normal aortas were obtained from autopsies. Using XPCT (effective pixel size, 12.5 μm; density resolution, 1 mg/cm³), the density of the tunica media (TM) in each sample was measured at eight points. The specimens were subsequently analyzed pathologically.

Results

The density of the TM was almost constant within each normal aorta (mean, 1.081 ± 0.001 g/cm³). The mean density was significantly lower in the ATAAD aortas without MFS (1.066 ± 0.003 g/cm³; P < .0001) and differed significantly between the intimal and adventitial sides (1.063 ± 0.003 vs 1.074 ± 0.002 g/cm³, respectively; P < .0001). The overall density of the TM was significantly higher in the ATAAD aortas with MFS than those without MFS (1.079 ± 0.008 g/cm³; P = .0003), and greater variation and markedly different distributions were observed in comparison with the normal aortas. These density variations were consistent with the pathologic findings, including the presence of cystic medial necrosis and malalignment of the elastic lamina in the ATAAD aortas with and without MFS.

Conclusions

XPCT exhibited differences in the structure of the aortic wall in aortic dissection specimens with and without MFS and in normal aortas. Medial density was homogeneous in the normal aortas, markedly varied in those with MFS, and was significantly lower and different among those without MFS. These changes may be present in the TM before the onset of aortic dissection.

Mid-term outcomes of valve-sparing root reimplantation with leaflet repair

OBJECTIVES

Valve repair for aortic insufficiency (AI) requires a tailored surgical approach determined by the leaflet and aortic disease. In this study, we used a repair-oriented system for the classification of AI, and we elucidated long-term outcomes of aortic root reimplantation with this classification system.

METHODS

From 1999 to 2018, a total of 197 patients underwent elective reimplantation (mean age: 52.7 ± 17.7 years; 80% male). The aortic valve was tricuspid in 143 patients, bicuspid in 51 patients and quadricuspid in 3 patients. A total of 93 patients had type I AI (aortic dilatation), 57 patients had type II AI (cusp prolapse) and 47 patients had type III AI (restrictive). In total, 104 of the 264 patients (39%) had more than 1 identified mechanism.

RESULTS

In-hospital mortality was 0.5% (1/197). Mid-term follow-up (mean follow-up duration: 5.5 years) revealed a late mortality rate of 4.2% (9/197). Aortic valve reoperation was performed on 16 patients (8.0%). Rates of freedom from aortic valve replacement and freedom from aortic valve-related events at 10 years of follow-up were 87.0 ± 4.0% and 60.6 ± 6.0%, respectively; patients with type Ib AI (98.3 ± 1.7%; 80.7 ± 7.5%) had better outcomes than patients with type III AI (59.6 ± 15.6%; 42.2 ± 13.1%, P = 0.01). In patients with types II and III AI who had bicuspid aortic valves, rates of freedom from aortic valve-related events at 5 years of follow-up were 95.2 ± 4.7% and 71.7 ± 9.1%, respectively (P = 0.03).

CONCLUSIONS

This repair-oriented system for classifying AI could help to predict the durable aortic valve repair techniques. Patient selection according to the classification is particularly important for long-term durability.

CLINICAL TRIAL REGISTRATION NUMBER

B190050.

P1782Synchrotron-based 4D-X-ray Phase Tomography of fresh chordae tendineae of mitral valve

Background

Mechanical properties of chordae tendineae of mitral valve (MV) are still not fully investigated. Synchrotron-based X-ray phase tomography (XPCT) is a powerful tool to measure biological soft tissues. Recently, we have developed dynamic X-ray phase tomography (4D-XPCT) to discuss the dynamic phenomena of biological samples quantitatively and applied to chordae tendineae of MV (MVCT).

Purpose

This study evaluated 4-dimensional changes of MVCT and clarified structural changes of MVCT during cardiac cycles.

Methods

The X-ray energy for 4D XPCT was set to 20keV. The effective pixel size was 7.8μm. Fresh MVCT extracted from a pig heart were measured in the specially designed container filled with normal cold saline. MVCT installed on the sample stage was stretched and released with a continuous oscillation of 0.5Hz during a phase tomographic measurement. The amount of stretch was 400μm where a mechanical load caused by stretching was approximately 1N. In this measurement, projection images were acquired with a frame rate of 20Hz during a single sawtooth wave. Therefore, apparent frame rate of 20Hz is expected in 4D phase tomography. Cross section was determined by simple thresholding based on the density. In this case, the threshold was set to 1.018g/cm3.

Results

X-ray phase tomographic images of MVCT at the released (A) and stretched (B) conditions are shown in Fig. 1a. The load applied to the sample and change of the cross section obtained from tomography during stretching and releasing are shown in Fig. 1b and 1c, respectively. The diameter of chordae tendinea were changed approximately 2.5% during stretching and returned to initial diameter during releasing.

Figure 1

Conclusions

This result demonstrated that the 4D-XPCT had a capability to trace the detail of deformation process in the biological soft tissues during continuous oscillation. Even chordae tendinea are mainly consisted of collagen fibers, diameter of the chordae was changed according to stretching and releasing.

Descending aortic replacement for intimal angiosarcoma

Aortic angiosarcoma is an exceedingly rare clinical entity. A significant delay in diagnosis can occur due to its rareness and lack of specific clinical manifestation. A 71-year-old woman was admitted to the emergency department owing to an acute episode of abdominal pain. A computed tomography (CT) scan showed thoraco-abdominal aortic occlusion and splenic infarction. The patient was initially treated with descending aortic replacement for degenerative atherothrombotic aneurysm. An FDG-positron emission tomography-CT scan and biopsy ultimately confirmed the diagnosis of aortic angiosarcoma. This case highlights the difficulties of making an early diagnosis of aortic angiosarcoma.

Mid-term outcomes of simultaneous mitral valve repair in patients with miral regurgitation and concomitant annulo-aortic ectasia

OBJECTIVE

This study investigated the mid-term outcomes of simultaneous mitral valve repair in patients with mitral regurgitation (MR) and concomitant annulo-aortic ectasia.

METHODS

The study included 26 patients with MR and annulo-aortic ectasia [mean age 46.0 ± 19.9 (10-86) years] who underwent simultaneous mitral valve repair between January 2007 and March 2018. Of these 26 patients, 11 (42.3%) were diagnosed with Marfan syndrome and 10 (38.5%) with Barlow's disease. All patients underwent complete ring annuloplasty; a semi-rigid ring was used in 14 (53.8%) and a semi-flexible ring (anterior-flexible) in 12 patients (46.2%). All patients underwent valve-sparing root replacement using the reimplantation technique.

RESULTS

The overall 3-year survival rate was 95.7 ± 4.3%. The 3-year freedom from > moderate MR rate was 94.7 ± 5.1%, and the 3-year freedom from > moderate aortic regurgitation (AR) rate was 86.7 ± 7.3%. The 3-year freedom from reoperation rate was 100%. The 3-year freedom from > moderate MR rate was 100% in the semi-rigid ring group and 85.7 ± 13.2% in the semi-flexible ring group (log-rank test, p = 0.5371). The 3-year freedom from > moderate AR rate was 100% in the semi-rigid ring group and 72.9 ± 16.5% in the semi-flexible ring group (log-rank test, p = 0.0815).

CONCLUSIONS

Simultaneous mitral valve repair in patients with MR and concomitant annulo-aortic ectasia showed favorable mid-term outcomes.

Post-sternotomy deep wound infection following aortic surgery: wound care strategies to prevent prosthetic graft replacement†

OBJECTIVES

The aim of this study was to evaluate the early and long-term outcomes of our multidisciplinary strategy for treating deep sternal wound infection after aortic grafting, which consisted of debridement by a plastic surgeon, negative pressure wound therapy with continuous irrigation and chest wall reconstruction.

METHODS

We performed a retrospective analysis of 18 patients who had a deep sternal wound infection following aortic grafting through a median sternotomy between January 2009 and December 2017. All patients had organisms cultured from mediastinal tissue within 2 months from the initial aortic surgery. The prosthetic grafts were exposed in 15 patients during resternotomy. Our protocol involved repeat debridement and negative pressure wound therapy with continuous irrigation twice a week until the results of the culture were negative and chest wall reconstruction was complete.

RESULTS

The mean duration from primary aortic surgery to resternotomy was 23.7 ± 15.9 days. Except for 1 patient, 17 patients underwent chest wall reconstruction. The mean duration from resternotomy to chest wall reconstruction was 31.1 ± 28.0 days. The hospital mortality rate was 16.7% (3 patients), although no patients died of wound-related causes. The mean follow-up period was 2.9 ± 2.5 years. Overall survival was 69.6 ± 11.4% at 1 year and 54.2 ± 13.3% at 5 years. Freedom from reoperation for reinfection was 94.4 ± 5.4% at 5 years.

CONCLUSIONS

Our wound care strategy achieved acceptable early and late survival in patients who had deep sternal wound infection following aortic grafting. This strategy may benefit those who experience this devastating complication.

Comparison of early patency rate and long-term outcomes of various techniques for reconstruction of segmental arteries during thoracoabdominal aortic aneurysm repair

OBJECTIVES

This study aimed to analyse the early patency rate and long-term outcomes of reattached segmental intercostal arteries using graft interposition, single-cuff anastomosis or island reconstruction.

METHODS

We selected 172 consecutive patients who underwent open surgery for the thoracoabdominal aorta with reattachment of segmental arteries between October 1999 and March 2018. The early patency of segmental arteries was analysed using enhanced computed tomography. Segmental arteries were reconstructed using graft interposition (n = 111), single-cuff anastomosis (n = 38) or island reconstruction (n = 23).

RESULTS

The hospital mortality was 6.4%. Twenty patients developed spinal cord ischaemic injury (permanent, n = 12 or transient, n = 8). Spinal cord injury was found in 16, 3 and 1 patients in the graft interposition, single-cuff anastomosis and island reconstruction groups, respectively. Overall, 475 segmental arteries were reattached (mean number per patient 2.8 ± 1.3). The overall early patency rate was 63.4%. The patency rates in island reconstruction (91.2%) and single-cuff anastomosis (77.1%) were significantly better than that in graft interposition (54.0%; P < 0.01). However, 6 patients with island reconstruction of segmental arteries had an aneurysm formation at the intercostal artery reconstruction site, of whom 4 patients underwent reoperation during follow-up. None of the patients with graft interposition or single-cuff reattachment had a patch aneurysm in segmental arteries.

CONCLUSIONS

Island reconstruction and single-cuff anastomosis might offer better patency rates and prevent spinal cord ischaemic injury than graft interposition. Because some patients with island reconstruction required reoperation for patch aneurysms in segmental arteries, single-cuff anastomosis is preferable in terms of early- and long-term outcomes.

A successful report of mitral valve repair for parachute-like mitral valve in adult

A 65 year-old man was diagnosed with congestive heart failure secondary to severe mitral regurgitation resulting from a parachute-like asymmetrical mitral valve. We performed mitral annuloplasty and triangular resection of the thick tissue. The postoperative course was uneventful with no recurrence of mitral regurgitation.

Valve-Sparing Root Replacement in Elderly Patients With Annuloaortic Ectasia

BACKGROUND

We report early and midterm outcomes of elderly patients who underwent valve-sparing root replacement (VSRR) compared with younger patients and those with Bentall procedure.

METHODS

From October 1999 to October 2017, 73 patients greater than or equal to 65 years of age who underwent VSRR procedure were assigned as group S. Two hundred thirty-two VSRR patients who were between 15 and 64 years of age were assigned as group Y. Forty-five patients greater than or equal to 65 years of age who underwent Bentall procedure were assigned as group R. Preoperative grades of aortic regurgitation were 3.4 of 4 in group S, 3.1 of 4 in group Y, and 3.3 of 4 in group R (p = 0.07).

RESULTS

Hospital mortality was found in 1 (1.4%) patient in group S, 3 (6.7%) in group R, and 2 (0.9%) in group Y. Postoperative survival at 5 years was 88.5% in group S, 98.7% in group Y, and 82.4% in group R (p < 0.01). Freedom from more than mild aortic regurgitation at 5 years was 81.0% in group S and 85.4% in group Y. Follow-up echocardiography disclosed an effective aortic valve orifice area of 1.76 cm² in group R, 2.40 cm² in group Y, and 2.41 cm² in group S (p < 0.01), and peak pressure gradient across the aortic valve was 17.7 mm Hg in group R, 13.6 mm Hg in group Y, and 10.8 mm Hg in group S (p < 0.01).

CONCLUSIONS

Similar early and late outcomes were achieved in elder VSRR patients compared with younger patients. A better postoperative valve performance was demonstrated in VSRR patients than patients undergoing valve-replacement.

Anaesthetics stop diverse plant organ movements, affect endocytic vesicle recycling and ROS homeostasis, and block action potentials in Venus flytraps

Background and Aims

Anaesthesia for medical purposes was introduced in the 19th century. However, the physiological mode of anaesthetic drug actions on the nervous system remains unclear. One of the remaining questions is how these different compounds, with no structural similarities and even chemically inert elements such as the noble gas xenon, act as anaesthetic agents inducing loss of consciousness. The main goal here was to determine if anaesthetics affect the same or similar processes in plants as in animals and humans.

Methods

A single-lens reflex camera was used to follow organ movements in plants before, during and after recovery from exposure to diverse anaesthetics. Confocal microscopy was used to analyse endocytic vesicle trafficking. Electrical signals were recorded using a surface AgCl electrode.

Key Results

Mimosa leaves, pea tendrils, Venus flytraps and sundew traps all lost both their autonomous and touch-induced movements after exposure to anaesthetics. In Venus flytrap, this was shown to be due to the loss of action potentials under diethyl ether anaesthesia. The same concentration of diethyl ether immobilized pea tendrils. Anaesthetics also impeded seed germination and chlorophyll accumulation in cress seedlings. Endocytic vesicle recycling and reactive oxygen species (ROS) balance, as observed in intact Arabidopsis root apex cells, were also affected by all anaesthetics tested.

Conclusions

Plants are sensitive to several anaesthetics that have no structural similarities. As in animals and humans, anaesthetics used at appropriate concentrations block action potentials and immobilize organs via effects on action potentials, endocytic vesicle recycling and ROS homeostasis. Plants emerge as ideal model objects to study general questions related to anaesthesia, as well as to serve as a suitable test system for human anaesthesia.

Early and long-term outcomes of open surgery after thoracic endovascular aortic repair

OBJECTIVES

This study evaluated the early and long-term outcomes of open surgery after thoracic endovascular aortic repair.

METHODS

We conducted a retrospective review of 41 patients who underwent open surgery following thoracic endovascular aortic repair between October 1999 and July 2017. The mean interval from primary intervention to open surgery was 3.1 ± 3.7 years. Indications for open repair were endoleak in 14 patients, graft infection in 10 patients, false lumen dilatation in 9 patients, retrograde dissection in 5 patients, migration in 1 patient and additional aneurysm in 2 patients. Eight patients underwent emergent surgical conversions. The mean follow-up period was 4.2 ± 4.0 years.

RESULTS

Descending aortic replacement was performed in 15 patients; thoraco-abdominal aortic repair, in 14 patients; extensive arch to descending aortic replacement, in 5 patients; and total arch replacement, in 7 patients. Six (14.6%) patients died in the hospital. The 5-year survival rate was 73.7 ± 7.2%, and freedom from reintervention was 88.5 ± 6.4%.

CONCLUSIONS

Early outcomes of open surgical procedures after thoracic endovascular aortic repair were still suboptimal. However, hospital survivors had excellent long-term outcomes.

A case of type A acute aortic dissection with a common carotid trunk

We present a rare case of common carotid artery with acute type A aortic dissection. A 72-year-old woman underwent emergent aortic arch repair using Antegrade selective cerebral protection. Bottom-tapped cannulae were inserted into three orifices of arch vessels, however, regional cerebral oxygen saturation decreased after rewarming. We found that arch branches were in order from front to back, right subclavian artery, common carotid trunk, and left subcravian artery. The patient complicated stroke in the right middle cerebral artery.

Direct perfusion of the carotid artery in patients with brain malperfusion secondary to acute aortic dissection

OBJECTIVE

Presenting our experience of direct perfusion of the carotid artery in patients with brain malperfusion secondary to acute aortic dissection.

PATIENTS

Among 381 patients who underwent aortic repair for acute type A aortic dissection from October 1999 to August 2017, brain malperfusion was recognized in 50 patients. Nine patients had direct perfusion of the right carotid artery in patients with brain malperfusion secondary to acute aortic dissection. Age at surgery was 65.7 ± 13.5 years and three patients were male. Preoperative consciousness level was alert in one patients, drowsy in six, and coma in two. Five patients had preoperative hemiplegia. All patients showed a blood pressure difference between the upper extremities and eight patients showed more than 15% difference of rSO₂. Seven patients had a temporary external active shunt from the femoral artery to the right common carotid artery preoperatively. Two patients had direct perfusion to the right common carotid artery during cardiopulmonary bypass or in the intensive care unit after surgery because of a sudden decrease of rSO₂ and cessation of carotid artery flow. Antegrade cerebral perfusion was used in all patients. Total arch replacement was performed in six patients and hemiarch in three.

RESULTS

The hospital mortality was 33% (3 patients). Causes of death were huge hemispheric brain infarction or anoxic brain damage in two patients and myocardial infarction in one. The postoperative neurological outcome was alert in four, hemiplegia in two, and coma in three, but five patients showed some improvement of neurological signs.

CONCLUSION

Aggressive direct reperfusion of the carotid artery before the aortic repair may reduce neurological complications in patients with preoperative brain malperfusion secondary to acute aortic dissection.

Abstract 490: Quantitative and Dynamic Measurements of Aortic Wall of Acute Type-A Aortic Dissection With X-Ray Phase-Contrast Tomography

Objectives: We previously reported excellent findings of X-ray phase-contrast tomography (PCX) for visualization of the formalin-fixed human aortic wall samples, and PCX enabled to demonstrate changes of tunica media in acute type A aortic dissection (AADA) . This study evaluates quantitative and dynamic measurements of fresh aortic wall samples of AADA with this modality.

Methods: Fresh human aortic samples of the ascending aorta (n=7) were obtained during emergent aortic repair for AADA. Formalin-fixed human aortic walls of AADA (n=15) and normal aorta (n=15) were also investigated. PCX is approximately 1000 times more sensitive than absorption-contrast X-ray imaging and effective resolution of PCX is 11.7 μm. Quantitative and dynamic measurement has been developed to visualize changes in imaging of fresh aortic wall under various tensile force to simulate physiological condition, in which aortic wall is stretched according to blood pressure.

Results: In normal aorta, quantitative measurement of density of the media was 1.095±0.003(g/cm3), and no different between intimal side (1.083±0.002) and adventitial side (1.085±0.003). On contrast, in formalin-fixed aorta of AADA, the medial density was 1.063±0.027, significantly lower than normal aorta (Figure-1), and different between intimal side and adventitial side (1.061±0.008 vs 1.081±0.011, respectively; p<0.005). In fresh sample of AADA, distribution of the medial density was equal to that of formalin-fixed aorta and differences of the medial density were clearly observed with elevation of tensile force of the aortic wall (Figure-1). These differences in density within tunica media were well correlated with distribution of elastic fibers and existence of cystic medial necrosis in pathological analysis.

Conclusions: X-ray phase-contrast tomography was a strong modality to understand aortic structures and pathogenesis of acute type A aortic dissection.

Is the tiger shark Galeocerdo cuvier a coastal species? Expanding its distribution range in the Atlantic Ocean using at-sea observer data

The occurrence of tiger shark Galeocerdo cuvier in the Atlantic Ocean was assessed using at-sea observer data from multiple pelagic longline fisheries. Geographic positions of 2764 G. cuvier recorded between 1992 and 2013 and covering a wide area of the Atlantic Ocean were compared with the currently accepted distribution ranges of the species. Most records fell outside those ranges in both the Southern and Northern Hemispheres, which strongly suggests that the distribution range of G. cuvier in the open ocean is considerably larger than previously described.

Habitat and food partitioning of billfishes (Xiphioidei)

Species composition and food habits of four istiophorid billfishes were investigated and compared in three different tropical areas of the eastern North Pacific Ocean by longline operations from September to November 2004. Sailfish Istiophorus platypterus, shortbill spearfish Tetrapturus angustirostris and blue marlin Makaira nigricans had specific habitat preferences and mainly occurred in the near-continent area (13-16 degrees N; 103-107 degrees W), the open-ocean area (16-18 degrees N; 118-134 degrees W) and the near-equator area (5 degrees N; 104-120 degrees W). Small (<140 cm in lower jaw-fork length) striped marlin Kajikia audax mainly occurred in the near-continent area; however, large (>/=140 cm) individuals occurred throughout all three areas. Prey compositions of large K. audax in the three areas were different from one other reflecting the prey availability in each area. In the open-ocean area, molid fishes were dominant in mass for both large K. audax (49%) and T. angustirostris (73%), and large K. audax also fed on ostraciid (33%) and scombrid fishes (15%). In the near-continent area, tetraodontid fishes were dominant for large and small I. platypterus (54, 57%), and both large and small K. audax also fed on tetraodontid fishes (3, 12%). Large K. audax in this area fed mainly on scombrid fishes (86%). These results indicate that large K. audax show overlaps but little segregations of its prey with other billfishes. In the near-equator area, stomach contents of large K. audax and M. nigricans were few and billfish prey items were thought to be scarce.