Finite element analysis and computational fluid dynamics to elucidate the mechanism of distal stent graft-induced new entry after frozen elephant trunk technique.

OBJECTIVES: Distal stent graft-induced new entry (dSINE), a new intimal tear at the distal edge of the frozen elephant trunk (FET), is a complication of FET. Preventive measures for dSINE have not yet been established. This study aimed to clarify the mechanisms underlying the development of dSINE by simulating the mechanical environment at the distal edge of the FET. METHODS: The stress field in the aortic wall after FET deployment was calculated using finite element analysis. Blood flow in the intraluminal space of the aorta and FET models was simulated using computational fluid dynamics. The simulations were conducted with various oversizing rates of FET ranging from 0 to 30% under the condition of FET with elastic recoil. RESULTS: The elastic recoil of the FET, which caused its distal edge to push against the greater curvature of the aorta, induced a concentration of circumferential stress and increased wall shear stress (WSS) at the aorta. Elastic recoil also created a discontinuous notch on the lesser curvature of the aorta, causing flow stagnation. An increase in the oversizing rate of the FET widened the large circumferential stress area on the greater curvature and increases the maximum stress. Conversely, a decrease in the oversizing rate of the FET increased the WSS and widened the area with high WSS. CONCLUSIONS: Circumferential stress concentration due to an oversized FET and high WSS due to an undersized FET can cause a dSINE. The selection of smaller-sized FET alone might not prevent dSINE.

Outcomes of fenestrated frozen elephant trunk technique in 150 patients with acute type A aortic dissection.

Objective: The fenestrated frozen elephant trunk (FET) technique provides proximalization of distal anastomosis and antegrade blood flow into supra-aortic vessels through fenestration in a FET. We investigated the outcomes of the fenestrated FET technique in acute type A aortic dissection. Methods: We evaluated 150 patients who underwent arch repair using the fenestrated FET technique for acute type A aortic dissection between July 2014 and January 2023. FET was deployed under hypothermic circulatory arrest and manually fenestrated under direct vision on the supra-aortic vessel aspect. Fenestration was performed for the left subclavian artery alone in 139 patients, 2 supra-aortic vessels in 9 patients, and total supra-aortic vessels in 2 patients. Fixation around fenestration site for endoleak prevention was performed in 48 patients. Results: The overall 30-day mortality rate was 4.7% (7 out of 150). Two patients developed paraparesis. Adequate blood flow into the supra-aortic vessels through fenestrations were confirmed in all patients at discharge. The false lumen thrombosis rate at the distal edge of FET was 96.6%. The median follow-up period was 28 months. The 1-year and 3-year overall survival rate was 89.1% and 84.5%, respectively. During the follow-up period, neither fenestration occlusion nor stroke was noted in the cerebral area perfused via the fenestration. Distal stent graft-induced new entry was noted in 2 patients. Conclusions: The fenestrated FET technique is a straightforward and secure procedure for selected patients with acute type A aortic dissection. This technique can facilitate arch repair.

A Case of Acute Aortic Occlusion Occurring in Association with COVID-19 Infection and Ulcerative Colitis.

A 53-year-old woman visited her district hospital complaining of right lower limb numbness 8 days after being diagnosed with COVID-19. She had been suffering diarrhea for 25 days before the hospital visit. Computed tomography showed multiple arterial and venous thromboses, and anticoagulation with a therapeutic dose of heparin was initiated. Acute aortic occlusion occurred on hospital day 5, and balloon thromboembolectomy was performed for revascularization of the lower limbs 9 hours after onset. Ulcerative colitis was diagnosed on postoperative day 7. With the anticoagulation and immunosuppression therapy, no thromboembolic event occurred postoperatively.

Morphological characteristics and outcomes of aortic repair of acute type A aortic dissection occurring in patients with aortic arch branching variants.

PURPOSE: To investigate the morphological characteristics and operative outcomes of acute type A aortic dissection (ATAAD) in patients with aortic arch variants. METHODS: Of 616 patients with ATAAD, 97 (15.7%) had aortic arch variants, including bovine aortic arch (BAA, n = 66), isolated left vertebral artery (ILVA, n = 25), and aberrant subclavian artery (ASA, n = 6). The characteristics and outcomes were compared between the normal branching group (control, n = 519) and the total/individual arch variant groups. RESULTS: Compared to the control group, arch entry was more prevalent in the BAA (18.5% vs. 31.8%) and ILVA groups (44%) (both, P < 0.05), and right common carotid arterial occlusion was less common in the arch variant group (6.7% vs. 0%, P = 0.017). The in-hospital mortality (9.2% vs. 9.3%), new-onset stroke (7.3% vs. 7.2%), and 5-year survival (81.7% vs. 78.8%) did not differ markedly between the control and arch variant groups. Arch repair was performed in 28.9% (28/97) of the arch variant group using 3-4 vessel antegrade cerebral perfusion, with 3.8% in-hospital mortality and a 15.4% stroke rate, which were comparable to those of the control group. CONCLUSIONS: Aortic arch variants may influence tear location and involvement of the supra-arch vessels but may not affect postoperative outcomes.

Comparison between Zone 2 and Zone 3 distal anastomoses for aortic arch replacement in terms of invasiveness.

OBJECTIVES: Zone 2 anastomosis with total cervical branch reconstruction for acute type A aortic dissection and aortic arch aneurysms became possible after stent-graft introduction. This may be an easier procedure and reduce the risk of recurrent laryngeal nerve palsy. Therefore, this study aimed to compare the outcomes between Zone 2 and Zone 3 distal anastomoses. METHODS: After evaluating the patient data in our institute between April 2016 and April 2022, the patients in whom distal anastomosis was performed at Zone 2 with a stent-graft were defined as the Zone 2 group (n = 70). The patients in whom distal anastomosis was performed at Zone 3 were defined as the Zone 3 group (n = 24). RESULTS: The incidence of new-onset recurrent nerve palsy was one patient (1.4%) in the Zone 2 group and six patients (25.0%) in the Zone 3 group (p < 0.001). The lower body perfusion arrest time was 44.3 ± 9.1 min in the Zone 2 group and 52.9 ± 12.8 min in the Zone 3 group (p = 0.005). There were no significant differences in in-hospital mortality and morbidities. Multivariable analysis showed that only age was an independent predictor of overall mortality. CONCLUSIONS: Performing distal anastomosis at Zone 2 with a frozen elephant trunk or stent-graft reduced the lower body perfusion arrest time and possibly prevented recurrent nerve palsy.

Surgical techniques using an attached patch for large left ventricular pseudoaneurysm after inferior acute myocardial infarction.

We report a case of large left ventricular pseudoaneurysm after inferior acute myocardial infarction. Patch repair is commonly performed; however, only a few studies have described specific surgical techniques for left ventricular pseudoaneurysm repair of the inferior left ventricular wall. As an optimal repair technique for left ventricular pseudoaneurysm of the inferior left ventricular wall is lacking, we believe our technique is safe and effective in repairing this pathology.

Morphologic prognostic factor for thoracoabdominal aortic dilation after acute type A dissection repair.

OBJECTIVES: Risk factors for late-term aortic dilation after acute type A aortic dissection repair have not been well examined. The goal of this study was to determine the relationship between the abdominal aortic true lumen location and thoraco-abdominal aortic dilation after surgical repair for acute type A aortic dissection. METHODS: Patients who were preoperatively diagnosed with acute type A aortic dissection between April 2014 and July 2022 were included in this study. We evaluated the renal artery-level dissected aortic morphology and classified the study population into 2 groups: the ventral (those with the true lumen located on the ventral side) and the dorsal (other patients not assigned to the ventral group) groups, based on the location of the true lumen. Aortic dilation was defined as thoraco-abdominal aortic expansion ≥5 mm on 1-year postoperative computed tomography images. RESULTS: We examined 49 surgical patients who were assigned to the ventral (n = 22) and dorsal (n = 27) groups. The number of patients with ≥5 mm thoraco-abdominal aortic dilation after the operation was significantly higher in the ventral group than in the dorsal group (90.9% vs 51.9%, P = 0.009). The multivariable logistic regression analysis showed that the ventral type was an independent prognostic factor for thoraco-abdominal aortic dilation after the operation (odds ratio, 6.01; 95% confidence interval, 1.56-23.77; P = 0.009). CONCLUSIONS: The location of the true lumen of the abdominal aorta in acute type A aortic dissection may be a prognostic factor for thoraco-abdominal aortic dilation after surgical repair.

Appropriate sizing of the frozen elephant trunk: How to predict proximal descending aortic diameter prior to dissection?

OBJECTIVE: The predissection aortic diameter is the best reference for determining the size of the frozen elephant trunk in aortic dissection. We aimed to develop a new prediction method to estimate the predissection diameter of proximal descending aorta. Furthermore, we evaluated the accuracy of the estimated predissection proximal descending aortic diameters calculated using 3 prediction methods. METHODS: A total of 39 patients with acute type A aortic dissection who underwent predissection computed tomography were included in derivation sets. We measured the aortic dimensions at 3 levels of the proximal descending aorta: 5, 10, and 15 cm from zone 2. We developed a new prediction method-postdissection aortic diameter divided by 1.13 (AoDNew factor)-and estimated the predissection aortic diameter using the new and previously proposed methods by Rylski (AoDRylski) and Yamauchi (EquationYamauchi). Furthermore, we validated the new prediction method using a validation dataset with 24 patients. RESULTS: The rate of bias ≤2 mm was significantly greater with EquationYamauchi and AoDNew factor than with AoDRylski in the derivation group at each level of the proximal descending aorta (P < .001). In the validation group, the rate of bias ≤2 mm was significantly greater with EquationYamauchi and AoDNew factor than with AoDRylski at 10 cm and 15 cm from zone 2 (10 cm: P = .014, 15 cm: P < .001). CONCLUSIONS: These results suggest that the new prediction method can be used as a simple and accurate estimation method for the predissection aortic diameter at the proximal descending aorta.

Prevention of postoperative delirium after cardiovascular surgery: A team-based approach.

OBJECTIVE: We investigated the efficacy of the Delirium Team Approach program for delirium prevention after cardiovascular surgery. METHODS: We retrospectively investigated 256 patients who underwent cardiac or thoracic vascular surgery between May 2017 and May 2020. We compared the outcomes before and after implementation of the Delirium Team Approach program in December 2018. The program included the following components: (a) educational sessions for the medical team regarding delirium and its management, (b) review of preprinted physician orders for insomnia and agitation, and (c) routine screening for delirium. We investigated the early outcomes and effects of the Delirium Team Approach program on postoperative delirium. RESULTS: The incidence of postoperative delirium significantly decreased from 53.3% to 37.0% after implementation of the Delirium Team Approach program (P = .008). Although no intergroup differences were observed in the rates of stroke and reexploration for bleeding, the length of intensive care unit stay and the overall length of postoperative hospital stay were shorter in the postintervention group. Hospital costs, excluding surgery, and the cost during intensive care unit stay were lower in the postintervention group. Multivariable analysis showed that the Delirium Team Approach program was associated with a reduction in postoperative delirium (odds ratio, 0.38; 95% confidence interval, 0.21-0.67; P = .001). Other predictors of delirium included age, dementia, chronic kidney disease, and intubation time. After risk adjustment using propensity score matching, the rate of postoperative delirium was lower in the postintervention group. CONCLUSIONS: Implementation of the Delirium Team Approach program was associated with a lower incidence of postoperative delirium in patients who underwent cardiovascular surgery.

Comparison of bubble removal performances of five membrane oxygenators with and without a pre-filter.

When employing minimal invasive extracorporeal circulation (MiECC), the removal of bubbles in the circuit is important to prevent air embolism. We investigated the bubble removal performance of the FHP oxygenator with a pre-filter and compared it with that of four oxygenators, including the Fusion oxygenator, Quadrox oxygenator, Inspire oxygenator, and FX oxygenator. A closed test circuit filled with an aqueous glycerin solution was used. Air injection (10 mL) was performed prior to the oxygenator, and the number and volume of the bubbles were measured at the inlet and outlet of each oxygenator. At the inlet of the five oxygenators, there were no significant differences in the total number of bubbles detected. At the outlet, bubbles were classified into two groups according to the bubble size: ≥100 µm and <100 µm. Tests were performed at pump flow rates of 4 and 5 L/min. For bubbles ≥100 µm, which are considered clinically detrimental, the FHP was the lowest number and volume of bubbles at both pump flow rates compared to the other oxygenators. Regarding the bubbles <100 µm, the number of bubbles was higher in the FHP than those in others; however, the volume of bubbles was significantly lower at 4 L/min and tended to be lower at 5 L/min. The use of the FHP with the pre-filter removed more bubbles ≥100 µm in the circuit than that by the other oxygenators.

Association between frailty and long-term outcomes among patients undergoing thoracic aortic surgery via median sternotomy.

OBJECTIVE: Preoperative assessment of frailty is important for predicting postoperative outcomes. This study investigated the association between frailty and late outcomes among patients who underwent thoracic aortic surgery via median sternotomy. METHODS: A total of 1010 patients underwent thoracic aortic surgery via median sternotomy between April 2008 and December 2016. Patients < 65 years of age, those who underwent urgent or emergent surgery, and those with incomplete data were excluded; as such, 374 patients were ultimately included in the present study. Frailty was evaluated using an index comprising history of dementia, body mass index < 18.5 kg/m2, and hypoalbuminemia. A frailty score from 0 to 3 was determined by assigning 1 point for each criterion met. Frailty was defined as a score ≥ 1. Patients were categorized into of 2 groups: frail (n = 52) and non-frail (n = 322). The mean follow-up was 6.1 ± 3.1 years. RESULTS: Overall in-hospital mortality did not differ between the frail and non-frail groups. However, the incidence of re-exploration for bleeding and discharge to a health care facility was higher in the frail group than in the non-frail group. Multivariable analysis revealed that preoperative frailty was an independent predictor of late mortality during follow-up [hazard ratio 3.71 (95% confidence interval 2.16-6.37); P < 0.001]. CONCLUSION: Preoperative frailty was associated with late mortality after thoracic aortic surgery. Assessment of preoperative frailty using a simple frailty index may be useful in the decision-making process for elderly patients.

Fenestrated and covered frozen elephant trunk technique for management of chronic aortic dissection.

BACKGROUND: Reintervention for residual dissection after repaired type A aortic dissection remains challenging. When a frozen elephant trunk (FET) is used, the incidence of distal stent graft-induced new entry (d-SINE) is reportedly high in chronic dissection. AIMS: We report a case of successful redo arch repair using fenestrated and covered FET techniques for chronic residual aortic dissection. METHODS: After the arch was transected proximal to the left subclavian artery (LSCA), and a modified FET prosthesis, in which the distal edge of the FET was covered, was deployed. A fenestration was created in the FET on the LSCA aspect. RESULTS: The postoperative course was uneventful. DISCUSSION: The distal edge of the FET was covered to prevent d-SINE. Creation of a fenestration on the FET eliminates the need to reconstruct the LSCA. CONCLUSION: The fenestrated FET technique simplifies redo arch repair and the covered FET technique can potentially prevent d-SINE.

Effects of a frozen elephant trunk on postoperative renal dysfunction in acute type A aortic dissection extending into the renal artery.

BACKGROUND: We investigated the effects of frozen elephant trunk (FET) implantation on clinical outcomes in patients with acute type A aortic dissection (ATAAD) extending into the renal artery (RA). METHODS: Between May 2016 and April 2021, 136 patients underwent surgery for ATAAD at our hospital. Patients who died within 7 days postoperatively and those without preoperative contrast-enhanced computed tomography (CT) data were excluded from the study. The remaining 125 patients were included in this study. A preoperative CT-documented RA abnormality was found in 53 patients. Clinical outcomes, including renal dysfunction and CT findings, were compared between 29 patients with and 24 patients without the FET prosthesis. RESULTS: Among the 53 patients with RA abnormalities, origin of the RA from the false lumen was the most common type of abnormality. The percentage of men and rate of arch repair were higher, and the operation, cardiopulmonary bypass, and lower body hypothermic circulatory arrest times were longer in the FET than in the non-FET group. Early mortality rates were similar between groups. The incidence of postoperative acute kidney injury (AKI) was lower in the FET group (35% vs. 67%, p = 0.028). Multivariable analysis showed that FET implantation was associated with a low incidence of AKI (odds ratio: 0.28, 95% confidence interval: 0.08-0.96; p = 0.043). Among the 125 patients with or without RA abnormalities, no predictor of AKI was identified. CONCLUSION: FET implantation protected against postoperative AKI in patients with ATAAD extension into the RA.

Sutureless repair techniques for post-infarction left ventricular free wall rupture.

Left ventricular free wall rupture after acute myocardial infarction is uncommon but lethal and is still associated with high mortality rates. This paper presents the surgical treatment options and clinical management for post-infarction left ventricular free wall rupture. Various types of techniques, specifically sutureless repair using TachoComb/TachoSil, and intraoperative video images are discussed. Currently, sutureless repair is the most recommended treatment option when possible. However, appropriate selection of the surgical procedure remains important.

Predictive factors of distal stent graft-induced new entry after frozen elephant trunk procedure for aortic dissection.

OBJECTIVES: The incidence rate of distal stent graft-induced new entry (d-SINE) after frozen elephant trunk technique for aortic dissection remains controversial. The aim of this study was to investigate the incidence and seek the clinical and anatomical predictive factors. METHODS: This study is a retrospective multicentre evaluation of complications including d-SINE, aortic events and reintervention after the frozen elephant trunk procedure for aortic dissection. RESULTS: Our cohort included a total of 177 consecutive patients who underwent the frozen elephant trunk procedure for acute and chronic aortic dissection at 5 centres in Japan from May 2014 to March 2021. The incidence rate of d-SINE was 14.1% (25/177 patients). The cumulative incidence of d-SINE was 7.1%, 12.4% and 21.4% after 12, 36 and 60 months, respectively. d-SINE was not associated with mid-term survival rate. After competing risk regression analysis, onset time >48 h (subdistribution hazard ratio, 3.80; 95% confidence interval, 1.13-12.79; P = 0.031) was detected as an independent predictor. CONCLUSIONS: Awareness that there is a relatively higher incidence of d-SINE after frozen elephant trunk procedures is important. Non-hyper-acute phase was detected as an independent risk factor. Pre-emptive endovascular repair may be appropriate to protect new entry in high-risk patients.

Reconstruction of the left subclavian artery in arch repair: An end-to-side anastomosis technique.

BACKGROUND: The left subclavian artery (LSCA) is deeply located and difficult to visualize in some cases of total arch replacement. AIMS: We report an end-to-side anastomosis technique that enables safer and easier anatomical reconstruction of the LSCA. MATERIALS AND METHODS: Under Hypothermic circulatory arrest, the origin of the LSCA was ligated and pulled caudally. With clamping the distal LSCA, a graft was anastomosed to the anterior wall of the LSCA and antegrade cerebral perfusion to the LSCA was ensured through the anastomosed graft. Thereafter, distal anastomosis was performed proximal to the LSCA. RESULTS: The postoperative course was uneventful. DISCUSSION: Our reconstruction technique provides excellent exposure of the LSCA by pulling the origin of the LSCA caudally. Hemostasis after reconstruction is feasible, as the anastomosis in the anterior wall of the LSCA is easily visualized. CONCLUSION: The end-to-side anastomosis technique for LSCA reconstruction is a simple alternative in arch repair.

Covered frozen elephant trunk technique for prevention of distal stent graft-induced new entry.

Distal stent graft-induced new entry is not rare after frozen elephant trunk implantation. We report a case of covered frozen elephant trunk placement for prevention of distal stent graft-induced new entry. Coverage of the rigid distal stent edge using a graft reduces mechanical stress on the intima and radial force of the distal stent; therefore, this technique can potentially prevent distal stent graft-induced new entry.