The Number of Microbubbles Generated During Cardiopulmonary Bypass Can Be Estimated Using Machine Learning From Suction Flow Rate, Venous Reservoir Level, Perfusion Flow Rate, Hematocrit Level, and Blood Temperature.

GOAL: Microbubbles (MBs) are known to occur within the circuits of cardiopulmonary bypass (CPB) systems, and higher-order dysfunction after cardiac surgery may be caused by MBs as well as atheroma dispersal associated with cannula insertion. As complete MB elimination is not possible, monitoring MB count rates is critical. We propose an online detection system with a neural network-based model to estimate MB count rate using five parameters: suction flow rate, venous reservoir level, perfusion flow rate, hematocrit level, and blood temperature. METHODS: Perfusion experiments were performed using an actual CPB circuit, and MB count rates were measured using the five varying parameters. RESULTS: Bland-Altman analysis indicated a high estimation accuracy (R2 > 0.95, p < 0.001) with no significant systematic error. In clinical practice, although the inclusion of clinical procedures slightly decreased the estimation accuracy, a high coefficient of determination for 30 clinical cases (R2 = 0.8576) was achieved between measured and estimated MB count rates. CONCLUSIONS: Our results highlight the potential of this system to improve patient outcomes and reduce MB-associated complication risk.

Relationship Between Fibrosis, Endocardial Endothelial Damage, and Thrombosis of Left Atrial Appendage in Atrial Fibrillation.

BACKGROUND: Left atrial appendage (LAA) thrombus (LAAT) and ischemic stroke are considered important in atrial cardiomyopathy with progressive atrial fibrosis and endocardial endothelial damage. OBJECTIVES: This study aimed to obtain histological evidence to clarify the association between LAA fibrosis and endocardial endothelial damage with LAAT, ischemic stroke, and clinical risk factors. METHODS: Ninety-six patients with atrial fibrillation (AF) scheduled to undergo LAA excision during surgery were enrolled. They underwent transesophageal echocardiography before the surgery to validate the LAA function/morphology and LAAT presence or absence. The resected LAAs were subjected to Azan-Mallory staining and CD31 immunohistochemistry to quantify the degree of fibrosis and endocardial endothelial damage staged as F1-F4 and E1-E4 per the quantiles. RESULTS: Patients with an LAAT and/or ischemic stroke history had higher fibrosis degrees (18.4% ± 9.9% vs 10.4% ± 7.0%, P < 0.0001) and lower CD31 expressions (0.27 [IQR: 0.05-0.57] vs 1.02 [IQR: 0.49-1.65]; P < 0.0001). Also, higher CHADS2 was associated with a higher degree of fibrosis and lower CD31 expression. Multivariate logistic regression analysis revealed that endothelial damage (E4) was associated with an LAAT and/or ischemic stroke history independent of AF type (paroxysmal or nonparoxysmal) with an OR of 3.47. Among patients with nonparoxysmal AF, fibrosis (F4, OR: 3.66), endothelial damage (E4, OR: 4.62), and LAA morphology (non-chicken-wing, OR: 3.79) were independently associated with LAAT and/or stroke. The degree of fibrosis correlated significantly with endothelial damage (R = -0.38, P = 0.0001). CONCLUSIONS: These histological findings may be essential in considering the pathophysiology of LAAT and stroke within the atrial cardiomyopathy context.

Hepatic artery resection in distal cholangiocarcinoma.

PURPOSE: This study aimed to elucidate the safety and oncological outcomes of surgery with hepatic artery resection (HAR) for patients with distal cholangiocarcinoma. METHODS: The clinical data of patients with distal cholangiocarcinoma who underwent curative intent surgery at Hiroshima University between March 2009 and January 2021 were retrospectively analyzed. Eligible patients were classified according to the presence or absence of HAR (HAR and non-HAR group), and clinicopathological features and disease-free survival rates were compared between the two groups. RESULTS: Among the 60 patients analyzed, eight patients had received HAR, and the remaining 52 patients had not. The rate of portal vein resection, T stage, and the number of metastasized lymph nodes in the HAR group were significantly greater than those in the non-HAR group (p < 0.001, p = 0.00695, and p = 0.0480, respectively). Postoperative severe complication was confirmed in one patient, and there were no in-hospital deaths in the HAR group. Seven of 8 patients in the HAR group showed recurrence during follow-up, and of those, six patients showed early recurrence within 1 year postoperatively. The disease-free survival time in the HAR group was significantly shorter than that in the non-HAR group (median: 7.4 m vs. 34.2 m, respectively) (p < 0.001). Multivariate analysis revealed that lymph node metastasis and HAR were significant risk factors for predicting the adverse disease-free survival time (hazard ratio (HR), 3.21; p = 0.0142; HR, 4.47; p = 0.0346, respectively). CONCLUSIONS: Patients with distal cholangiocarcinoma who underwent surgery with HAR tended to show early recurrences, although HAR could be performed safely.

Relationship Between Periodontitis and Atrial Fibrosis in Atrial Fibrillation: Histological Evaluation of Left Atrial Appendages.

BACKGROUND: Atrial fibrosis contributes to the onset and persistence of atrial fibrillation (AF) and AF-related stroke. Periodontitis, a common infectious and inflammatory disease, aggravates some systemic diseases. However, the association of periodontitis with AF and with atrial fibrosis has remained unclarified. OBJECTIVES: The authors aimed to elucidate the relationship between periodontitis and atrial fibrosis by studying resected left atrial appendages (LAAs). METHODS: Seventy-six patients with AF (55 with nonparoxysmal AF, 25 with mitral valve regurgitation, 18 with LAA thrombus) who were scheduled to undergo LAA excision during cardiac surgery were prospectively enrolled. All patients underwent an oral examination, and the remaining number of teeth, bleeding on probing, periodontal probing depth, and periodontal inflamed surface area (PISA) were evaluated as parameters of periodontitis. The degree of fibrosis in each LAA was quantified by Azan-Mallory staining. RESULTS: Bleeding on probing (R = 0.48; P < 0.0001), periodontal probing depth of ≥4 mm (R = 0.26; P = 0.02), and PISA (R = 0.46; P < 0.0001) were positively correlated with atrial fibrosis. Among patients with >10 remaining teeth, PISA was positively and strongly correlated with atrial fibrosis (R = 0.57; P < 0.0001). After adjustments for age, AF duration, BMI, mitral valve regurgitation, and CHADS2 (congestive heart failure, hypertension, age, diabetes, previous stroke/transient ischemic attack) score, PISA was significantly associated with atrial fibrosis (ß = 0.016; P = 0.0002). CONCLUSIONS: The authors histologically revealed the association of periodontitis with atrial fibrosis. This indicates that periodontitis, which is modifiable, is likely a risk factor for AF.

Treatment of celiac artery rupture with a hybrid procedure involving aortic stent grafting and open surgery in a patient with neurofibromatosis type 1.

Neurofibromatosis type 1 is associated with vascular fragility, and vascular disease is the second leading cause of death in these patients. A 42-year-old woman with neurofibromatosis type 1 was transferred to our hospital owing to shock. A computed tomography scan revealed a ruptured celiac artery aneurysm, which had expanded from 14 to 26 mm in 1 day. The survival rate of patients with celiac artery rupture is extremely low, and there is no consensus on treatment. Here, we successfully performed a hybrid procedure with emergent implantation of aortic stent grafts for life-saving treatment and subsequent laparotomy for complete hemostasis.

Neural Network-based Estimation of Microbubbles Generated in Cardiopulmonary Bypass Circuit: A Clinical Application Study.

The cardiopulmonary bypass system used in cardiac surgery can generate microbubbles (MBs) that may cause complications, such as neurocognitive dysfunction, when delivered into the blood vessel. Estimating the number of MBs generated, thus, is necessary to enable the surgeons to deal with it. To this end, we previously proposed a neural network-based model for estimating the number of MBs from four factors measurable from the cardiopulmonary bypass system: suction flow rate, venous reservoir level, blood viscosity, and perfusion flow rate. However, the model has not been adapted to the data collected from actual surgery cases. In this study, the accuracy of MBs estimated by the proposed model was examined in four clinical cases. The results showed that the coefficient of determination between estimated MBs and the measured MBs throughout the surgeries was R2=0.558 (p<0.001). We found that the surgical treatments, such as administration of drugs, fluids and blood transfusions, increased the number of measured MBs. The coefficient of determination increased to R2= 0.8762 (p<0.001) by excluding the duration of these treatments. This result indicates that the model can estimate the number of MBs with high accuracy under the clinical environment.

Mesenteric approach in pancreas-preserving partial duodenectomy for aortic graft-duodenal fistula: a case report.

An aortic graft-duodenal fistula commonly requires graft replacement and duodenectomy. However, the appropriate surgical approach to the duodenum with aortic graft fistula remains unclear. Herein, we describe the case of an 85-year-old male patient who underwent a pancreas-preserving partial duodenectomy using the mesenteric approach for aortic graft-duodenal fistula. The patient presented with hemorrhagic shock and duodenal bleeding 2 years after undergoing open aortic graft replacement. He first underwent emergent endovascular aortic repair with an artificial vascular graft to achieve hemostasis. Although his general condition stabilized following endovascular treatment, duodenal endoscopy revealed an aortic graft-duodenal fistula, exposing the artificial vascular graft via the third portion of the duodenum. As the radical treatment for aortic graft-duodenal fistula, open graft replacement and pancreas-preserving partial duodenectomy were performed using the mesenteric approach which helps to divide the pancreas and duodenum. The patient recovered without any major complications, such as postoperative pancreatic fistula, and was discharged. In conclusion, the mesenteric approach in partial duodenectomy for aortic graft-duodenal fistula could be safely performed. This procedure is useful to approach the duodenum fixed by fistula formation, which may help reduce intraoperative blood loss, operative time, and surgical invasiveness.

Successful Aortic Remodeling Through the Candy-Plug Technique for Chronic Type B Aortic Dissection.

PURPOSE: To describe the efficiency of the candy-plug technique using an Excluder aortic extender and obtain optimal aortic remodeling. CASE: A 46-year-old male patient had a history of acute type B aortic dissection and progressive dilation of the descending aorta (53 mm diameter) with a patent false lumen. He was treated with the candy-plug technique, using an Excluder aortic extender of 32-45 mm was placed and a 16-mm Amplatzer Vascular Plug II. No technical complications were observed in the patient. Good aortic remodeling was observed after 6 months, CT showed complete thrombosis of the false lumen and reduction of the maximum perpendicular diameter of the descending aorta from 53 to 47 mm. The diameter of the other proximal zones of the descending aorta was 45-47 mm, and the Excluder aortic extender changed into an elliptical shape. This is the first report of good aortic remodeling with an elliptical shape by performing the candy-plug technique. DISCUSSION: The candy-plug technique using an Excluder aortic extender is an improved method for occluding the false lumen as it provides improved aortic remodeling. The 2 indications for this surgery are limited. A large entry point in the descending abdominal aorta that is more peripheral than the candy-plug position must be visible on contrast-enhanced CT and the false lumen is not too large. We consider candy-plug placement in the true lumen central to the TEVAR to avoid occluding the artery of Adamkiewicz, since we have to avoid the thrombosis of the peripheral false lumen where a candy-plug was placed. Since it is unclear whether long-term results are satisfactory, we must continue to study chronic aortic type B dissection.

Association between left atrial appendage fibrosis and thrombus formation: A histological approach.

INTRODUCTION: Although recent echocardiographic studies have suggested that left atrial appendage (LAA) remodeling contributes to the development of LAA thrombus (LAAT), histological evidence is absent. The objective of this study was to examine clinical parameters and histological findings to clarify the factors involved in LAAT formation. METHODS: A total of 64 patients (no atrial fibrillation [AF], N = 22; paroxysmal AF, N = 16; nonparoxysmal AF, N = 26) who underwent LAA excision during surgery were enrolled. Transthoracic and transesophageal echocardiography were performed before surgery. We evaluated the fibrosis burden (%) in the excised LAA sections with Azan-Mallory staining in patients with a LAAT compared with those without. RESULTS: Patients with paroxysmal and non-paroxysmal AF had a higher LAA fibrosis burden than those without AF (p = .005 and p < .0001, respectively). Among the patients enrolled, 16 had a LAAT and 15 of them had nonparoxysmal AF. Among the nonparoxysmal AF patients, those with a LAAT had significantly higher LAA fibrosis burden than those without (23.8% [14.8%-40.3%] vs. 12.8% [7.4%-18.2%], p = .004) and echocardiographic parameters of the left atrial volume index (R = 0.543, p = .01), LAA depth (R = 0.452, p = .02), and LAA flow velocity (R = - 0.487, p = .01) were correlated with the LAA fibrosis burden. CONCLUSION: This study provided histological evidence that LAA fibrosis is related to LAAT formation. Echocardiographic parameters of LAA remodeling and function were correlated with the LAA fibrosis burden.

Postoperative mediastinitis after cardiac surgery caused by Mycoplasma hominis: a case report.

BACKGROUND: Mycoplasma hominis is a human commensal bacterium of the urogenital tract, and extragenital infection caused by M. hominis has rarely been reported. The identification of M. hominis is challenging, and surgeons are generally not aware that this bacteria can cause postoperative infection. Here, we report a rare case of postoperative mediastinitis caused by M. hominis after cardiac surgery in an immunocompetent patient. CASE PRESENTATION: A 54-year-old man presented with pain and purulent discharge from the wound after aortic valve replacement and patent foramen ovale closure. However, Gram staining and culture of bacteria from the purulent discharge was negative, and empiric sulbactam/ampicillin therapy was not effective. This patient developed mediastinitis and rupture of a pseudoaneurysm of the ascending aorta caused by mediastinitis, and re-operation was performed. Then, postoperative mediastinitis caused by M. hominis or Ureaplasma species was suspected and bacterial cultures targeting these pathogens were performed. M. hominis was identified from abscess and tissue obtained from the surgical site and urine. A final diagnosis of postoperative mediastinitis caused by M. hominis was determined. The patient was initially treated with levofloxacin and then with minocycline for 3 weeks. The patient's clinical condition improved; the patient was transferred to another hospital. CONCLUSION: The role of M. hominis as a cause of postoperative infection might be underestimated in cardiac surgery. M. hominis should be considered when culture-negative purulent discharge is observed or there is no response to standard empiric treatment of postoperative infections.

Rupture of Abdominal Aortic Aneurysm Caused by Combined Type IIIb and Type Ia Endoleak with the Endurant II Endograft: A Case Report.

We report a case of combined types IIIb and Ia endoleak that developed 6 years after endovascular aneurysm repair (EVAR) with the Endurant II® endograft for abdominal aortic aneurysm (AAA). The patient presented with post-EVAR AAA rupture and underwent emergency open repair. We observed types IIIb and Ia endoleak and successfully performed felt banding to preserve the stent graft. Type IIIb endoleak with the Endurant® endograft is rare, and treatments have not been fully established. We summarized the case reports regarding type IIIb endoleak with the Endurant® endograft and mainly discussed the treatments.

Neural network-based modeling of the number of microbubbles generated with four circulation factors in cardiopulmonary bypass.

The need for the estimation of the number of microbubbles (MBs) in cardiopulmonary bypass surgery has been recognized among surgeons to avoid postoperative neurological complications. MBs that exceed the diameter of human capillaries may cause endothelial disruption as well as microvascular obstructions that block posterior capillary blood flow. In this paper, we analyzed the relationship between the number of microbubbles generated and four circulation factors, i.e., intraoperative suction flow rate, venous reservoir level, continuous blood viscosity and perfusion flow rate in cardiopulmonary bypass, and proposed a neural-networked model to estimate the number of microbubbles with the factors. Model parameters were determined in a machine-learning manner using experimental data with bovine blood as the perfusate. The estimation accuracy of the model, assessed by tenfold cross-validation, demonstrated that the number of MBs can be estimated with a determinant coefficient R2 = 0.9328 (p < 0.001). A significant increase in the residual error was found when each of four factors was excluded from the contributory variables. The study demonstrated the importance of four circulation factors in the prediction of the number of MBs and its capacity to eliminate potential postsurgical complication risks.

Mid-Term Results of Frozen Elephant Trunk Technique for Chronic Aortic Dissection.

Objective: In this study, we report our experience using the frozen elephant trunk (FET) technique for chronic aortic dissection. Methods: Between January 2011 and December 2017, 15 patients underwent total arch replacement (TAR) with the FET technique for chronic aortic dissection (CAD). Results: Hospital mortality was 6.7% (n=1). No patients experienced spinal cord injury. Distal stent-induced new entry (dSINE) occurred in the early postoperative period in one patient. There were four unplanned additional operations to manage dSINE. Five patients suffered from dSINE, and aortoesophageal fistula developed in three of them. Short insertion length of the FET and large angle between the distal edge of the FET and the descending aorta were significantly more common in the dSINE group than in the non-dSINE group. The cumulative survival rates at 1, 3, and 5 years were 93.3%, 93.3%, and 66.4%, respectively. The cumulative aortic event-free rates at 1, 2, and 3 years were 85.7%, 77.1%, and 52.9%, respectively. Conclusion: The FET technique for CAD provided good early results. Short insertion length of the FET, however, can induce dSINE, which requires an additional operation at mid-term. Thus, surgical indication of the FET technique for CAD must be discussed.

Total Aortic Arch Replacement after Thoracic Endovascular Aortic Repair Using Left Subclavian Arterial Perfusion.

We present the case of an 86-year-old male with an aortic arch saccular aneurysm who underwent zone 1 thoracic endovascular aortic repair (TEVAR) with debranching from the right subclavian artery to the left carotid and left subclavian arteries. The patient developed a type Ia endoleak 1 month later. Postoperative contrast computed tomography (CT) showed a hematoma around the aneurysm, concerning for impending rupture. He thus underwent emergency endograft removal and replacement with a one-branched graft using selective cerebral perfusion via the left subclavian artery perfusion. The left subclavian artery was used for systemic and cerebral perfusion without need for cannulation of the cervical arteries. The patient was successfully discharged 6 months after surgery.

Association between false lumen segmental arteries and spinal cord ischemia in type A acute aortic dissection.

BACKGROUND: Spinal cord ischemia (SCI) and paraplegia are complications of surgery for type A acute aortic dissection (TAAAD). Since the segmental arteries play a key role in SCI, this study evaluated the association between SCI and false lumen segmental arteries (FLSAs: segmental arteries originating from the false lumen). METHODS: The study included 101 consecutive TAAAD patients (mean age, 66±13; range, 34-89 years) who underwent surgery from January 2011 to April 2017. The diagnosis of TAAAD and the number of FSLAs were determined by preoperative computed tomography (CT). Patients were divided into two groups according to the number of FLSAs at the Th9-L2 level: Group A (N.=13), ≥8 FLSAs; and group B (N.=88), ≤7 FLSAs. Preoperative, perioperative, and postoperative findings were compared between the groups, and risk factors for SCI were evaluated. RESULTS: The frequency of preoperative paralysis was significantly higher in Group A than Group B (P=.0070). The overall incidence of postoperative SCI was 8% (8/101) and significantly higher in Group A than Group B (5/13 [45%] vs. 3/88 (4%), P<0.0001). Hospital mortality was 8% (8/101) and significantly higher in Group A than Group B (3/13 [23%] vs. 5/88 [6%], P=.0302). Multivariate analysis showed that the independent risk factors for SCI were ≥8 FLSAs at Th9-L2 (odds ratio [OR], 20.4; 95% confidence interval [95% CI], 3.34-124.9, P=0.0011) and diabetes mellitus (OR, 22.3; 95% CI, 1.69-294.5; P=0.0184). CONCLUSIONS: In patients who underwent surgery for TAAAD, ≥8 FLSAs at the Th9-L2 levels on preoperative CT was a risk factor for SCI.

Three-step surgical treatment of aortoesophageal fistula after thoracic endovascular aortic repair: A case report.

INTRODUCTION: Aortoesophageal fistula (AEF) is a fatal complication results in sudden massive hematemesis. Although thoracic endovascular aortic repair (TEVAR) is an established method of treating aortic aneurysms or aortic dissection, the number of AEF after TEVAR is recently increasing due to the spread of TEVAR. However, the therapeutic strategy for AEF remains controversial. PRESENTATION OF CASE: We describe a 71-year-old man with Stanford B aortic dissection and aortic aneurysm rupture treated by TEVAR who developed AEF between the thoracic aorta and upper thoracic esophagus 20 months thereafter. We applied a three-step surgical procedure for this patient comprising resection of the esophagus as the infectious source, removal of an aortic aneurysm with stent-graft and replacement of the aorta, and final reconstruction of the esophagus. Thereafter, the patient resumed oral intake and has remained relapse-free for 24 months without adverse events. DISCUSSION: Previous reports have described simultaneous resection of the esophagus and aortic stent-graft via a left thoracotomy followed by a two-step surgical reconstruction of the esophagus. We applied a three-step procedure consisting of resections of the esophagus and aortic stent-graft on separate occasions followed by esophageal reconstruction in this patient. The first procedure in the three-step approach is less stressful than that of the two-step approach. CONCLUSION: The three-step surgical approach to treating AEF after TEVAR resulted in a good outcome for this patient. Thus, this surgical strategy is a useful option for treating AEF after TEVAR.

Delivery balloon rupture during transcatheter heart valve alignment procedure in extreme descending aorta tortuosity.

A 79-year-old man with a history of partial resection of the lung and the bladder due to cancer, hypertension, dyslipidemia, and heart failure, underwent transcatheter aortic valve replacement with a SAPIEN 3 (S3) valve (Edwards Lifesciences, Irvine, CA, USA). Preprocedural examination showed a bicuspid aortic valve and severe calcification of the leaflets. Computed tomography showed great tortuosity of the descending aorta. A 29-mm S3 valve prosthesis was advanced into the aorta, but a high degree of resistance was encountered in the middle of the descending aorta. The prosthesis was advanced to the level of aortic valve and an attempt was made to deploy the valve. However, the valve balloon did not expand. A balloon rupture was suspected. The balloon catheter was pulled back into the eSheath (Edwards Lifesciences), and the catheter and eSheath were removed together. Rupture of the balloon was confirmed. A new eSheath and prosthesis were prepared, with delivery supported with a Lunderquist guidewire (Cook Medical, Bloomington, IN, USA). The valve alignment procedure was performed in a straighter portion of the descending aorta. The new 29-mm S3 valve was then successfully implanted. .

Aorto-Esophageal Fistula Caused by Distal Stent Graft-Induced New Entry after Frozen Elephant Trunk Technique for Chronic Aortic Dissection.

We present a case of aorto-esophageal fistula (AEF) caused by distal stent graft-induced new entry (dSINE) after the frozen elephant trunk (FET) technique for chronic aortic dissection. We propose that the combination of the spring-back force and the radial force of the FET may play a role in the occurrence of dSINE, leading to AEF. In this case, we successfully performed a three-stage surgery, including esophagectomy, descending aortic replacement, and esophageal reconstruction. To prevent this critical complication, additional endovascular aortic repair should be performed if the FET is not positioned at the straight portion of the descending aorta.

Abdominal aortic aneurysm with occlusion of three primary mesenteric vessels treated by surgery with perfusion of the left iliac artery†.

A 64-year-old woman who underwent thoraco-abdominal aortic replacement for a Crawford type II aneurysm 11 years ago was referred to our hospital because of a residual juxtarenal abdominal aortic aneurysm. The coeliac, superior mesenteric and inferior mesenteric arteries were occluded. Collateral vessels from the left internal iliac artery to these 3 mesenteric arteries had developed. We performed open aneurysm repair using an extracorporeal circuit to maintain collateral flow to these mesenteric arteries.