[Surgical Treatment for Ruptured Thoracoabdominal Aneurysm Following Descending Aortic Replacement with Double Barrel Anastomosis].

A 75-year-old woman was diagnosed with type B acute aortic dissection 14 years ago and 3-channeled aortic dissection 7 years ago. She received total arch replacement 6 years ago and descending aortic replacement with double barrel anastomosis technique for distal anastomosis 5 years ago. Computed tomography( CT) revealed giant thyroid tumor and thoracoabdominal aortic aneurysm( 58 mm in diameter). She suffered from back pain during her follow-up period. CT revealed ruptured thoracoabdominal aortic aneurysm. First, the false lumen of descending aorta was closed by thoracic endovascular aortic repair, and then thoracoabdominal aortic replacement was performed uneventfully.

[Amyloidosis Diagnosed Following Aortic Valve Replacement:Report of a Case].

A 76-year-old man had been under observation for nephrotic syndrome. He suffered from hypotension and transient loss of consciousness. He was diagnosed with thoracic aortic aneurysm and severe aortic valve stenosis. Ascending aorta replacement concomitant with aortic valve replacement was performed uneventfully. He was diagnosed with light chain amyloidosis by pathological examination of the resected ascending aorta. He was received referral treatment for amyloidosis.

[Stanford Type A Acute Aortic Dissection Complicated by Right Lung Hemorrhage:Report of a Case].

A 59-year-old woman was transferred to our hospital because of a sudden onset of chest and back pain. Computed tomography (CT) demonstrated Stanford type A acute aortic dissection with cardiac tamponade and right airway bleeding. Hemorrhage from ruptured false lumen extended along the pulmonary artery (PA), compression of the right PA were recognized due to hematoma surrounding the PA. An emergency operation was performed. The primary tear was located at the distal aortic arch, and total arch replacement with frozen elephant trunk was performed. During the operation, she had airway bleeding. The bleeding was thought to be due to the hematoma extending along the pulmonary artery. She was extubated 7th postopratively. She was discharged 44 days after the operation.

[Delayed Type â ¢b Endoleak After Thoracic Endovascular Aortic Repair for Thoracic Aortic Aneurysm: Report of a Case].

An 85-year-old woman underwent aortic arch replacement and thoracic endovascular aortic repair (TEVAR) 5 years ago. She suffered from chest and back pain. Computed tomography (CT) demonstrated enlargement of the aortic aneurysm by a type Ⅲb endoleak. TEVAR was performed to close a type Ⅲb endoleak with a relining technique uneventfully. Intraoperative completion aortography and postoperative CT confirmed the disappearance of a type Ⅲb endoleak. She was discharged 27 days after the treatment.

[Acute Type A Aortic Dissection Complicated by Cerebral Malperfusion and Leg Ischemia:Report of a Case].

An 82-year-old woman suddenly developed chest pain and apoplexy. Computed tomography (CT) showed acute type A aortic dissection, the true lumen in the brachicephalic artery was severely compressed by the faulse lumen. Pulsation in the either leg was not detected during induction of anesthesia. We evaluated the cerebral blood flow and lower extremity blood flow using near infrared spectroscopy (NIRS) during the operation, tissue oxygenation index (TOI) was continuously monitored during the operation. Cardiopulmonary bypass( CPB) was established by puncturing the true lumen in the ascending aorta and bicaval venous drainage. TOI was returned to normal range by CPB. Although the central repair (ascending aorta replacement) was performed, leg ischemia persisted. We performed ascending aorta-bifemoral bypass. After the operation, leg ischemia disappeared and CT revealed patency of the bypass graft. Postoperative course was uneventful without deterioration of neurological function. She was discharged 49 days after the operation.

[Very Late Stent Thrombosis during Perioperative Period of Aortic Valve Replacement:Report of a Case].

A 73-year-old man underwent drug eluting stent (DES) implantation in the left anterior descending artery (LAD) 11 years ago and in the right coronary artery (RCA) 8 years ago. He suffered from chest tightness and was diagnosed with severe aortic valve stenosis. Perioperative coronary angiography revealed no significant stenosis and thrombotic occlusion of the DES. Five days before operation, antiplatelet therapy was discontinued. Aortic valve replacement was performed uneventfully. But he developed chest pain and transient loss of consciousness, electrocardiographic changes were observed on the 8th postoperative day. Emergency coronary angiography revealed thrombotic occlusion of the drug eluting stent in the RCA, despite the postoperative oral adoministration of warfarin and aspirin. Percutaneous catheter intervention (PCI) restored the stent patency. Dual antiplatelet therapy (DAPT) was initiated immediately after the PCI, and anticoagulation therapy with warfarin was continued. Clinical symptons of stent thrombosis disappeared immediately after the PCI. He was discharged 7 days after the PCI.

[Gallbladder Necrosis after Surgery for Stanford Type A Aortic Dissection in an Elderly Patient:Report of a Case].

An 86-year-old woman who suffered from cardiac tamponade due to acute Stanford type A aortic dissection was admitted to our hospital. An emergency operation was performed uneventfully. She suffered from abdominal pain 13 days after the operation. Computed tomography( CT) scan revealed pericholecystic fluid and unclear gallbladder wall, revealing acalculous necrotizing cholecystitis. We performed open cholecystectomy and abdominal cavity drainage. No gallstones were observed. She underwent intensive treatment. She was discharged without complications 44 days after the cholecystectomy.

[Hybrid Treatment of the Intrathoracic Right Subclavian Artery Aneurysm:Report of a Case].

A 78-years-old woman was referred to our institution for the treatment of right subclavian artery (SCA) aneurysm. She previously underwent total arch replacement via median sternotomy approach. Preoperative computed tomography revealed a 55 mm sized SCA aneurysm. Stent graft was inserted from brachiocephalic artery to right common carotid artery via the graft anastomosed. The orifice of the right SCA was covered with stent graft inserted into the right common carotid artery-brachiocephalic artery and the right SCA was occluded with coils distal to the aneurysm, carotid-SCA bypass was performed with 8 mm ePTFE graft. Postoperative examination confirmed complete exclusion of the aneurysm and patency of the bypass graft. We thought that hybrid treatment for this patient was a less invasive alternative to conventional surgical procedure.

Quantifying scattering from dense media using two-dimensional impedance maps.

A better understanding of ultrasound scattering in a three-dimensional (3D) medium can provide more accurate methods for ultrasound tissue characterization. The possibility of using two-dimensional impedance maps (2DZMs) based on correlation coefficients has shown promise in the case of isotropic and sparse medium [Luchies and Oelze, J. Acoust. Soc. Am. 139, 1557-1564 (2016)]. The present study investigates the use of 2DZMs in order to quantify 3D scatterer properties of dense media from two-dimensional (2D) histological slices. Two 2DZM approaches were studied: one based on the correlation coefficient and the other based on the 2D Fourier transform of 2DZMs. Both 2DZM approaches consist in estimating the backscatter coefficient (BSC) from several 2DZMs, and then the resulting BSC was fit to the theoretical polydisperse structure factor model to yield 3D scatterer properties. Simulation studies were performed to evaluate the ability of both 2DZM approaches to quantify scattering of a 3D medium containing randomly distributed polydisperse spheres or monodisperse ellipsoids. Experimental studies were also performed using the histology photomicrographs obtained from HT29 cell pellet phantoms. Results demonstrate that the 2DZM Fourier transform-based approach was more suitable than the correlation coefficient-based approach for estimating scatterer properties when using a small number of 2DZMs.

Comprehensive backscattering characteristics analysis for quantitative ultrasound with an annular array: a basic study on homogeneous scattering phantom.

High-frequency ultrasound (HFU, >20 MHz) and quantitative ultrasound (QUS) methods permit a means to understand the relationship between anatomical and acoustic characteristics. In our previous research, we showed that analyzing the acoustic scattering with HFU was an effective method for noninvasive diagnosis. However, the depth of field (DOF) of HFU transducers was limited, which constrains the range of QUS analysis. In this study, we seek to improve the accuracy of HFU, QUS-based parameters on the envelope statistics and frequency-based analysis by using an annular array that allows for an extended DOF. A 20-MHz annular-array transducer with five elements was employed to obtain signals which were beamformed in post-processing. Two kinds of low concentration scattering phantoms were scanned with 30-µm step size. Two QUS analysis techniques were employed: the Nakagami distribution and the reflector method. The results demonstrated that the annular array provides a stable analysis over an extended axial range.

Ultrasound assessment of translation of microbubbles driven by acoustic radiation force in a channel filled with stationary fluid.

In this report, a method is proposed to quantify the translation of ultrasound contrast agent (UCA) microbubbles driven by acoustic radiation for the detection of channels filled with stationary fluid. The authors subjected UCA microbubbles in a channel with diameters of 0.1 and 0.5 mm to ultrasound pulses with a center frequency of 14.4 MHz. The translational velocity of the UCA microbubbles increased with the sound pressure and pulse repetition frequency (PRF) of the transmitted ultrasound. The mean translational velocity reached 0.75 mm/s at a negative peak sound pressure of 2.76 MPa and a PRF of 2 kHz. This trend agreed with the theoretical prediction, which indicated that the translational velocity was proportional to the square of the sound pressure and the PRF. Furthermore, an experiment was carried out with a phantom that mimics tissue and found that the proposed method aided in detection of the channel, even in the case of a low contrast-echo to tissue-echo ratio. The authors expect to develop the proposed method into a technique for detecting lymph vessels.

Thermoelastic wave generation and its longitudinal wave propagation measurement by a microscopic optical interferometer.

Laser ultrasonics is a noncontact measurement method that uses a laser-induced elastic wave source in combination with an optical surface displacement-tracking system. This study compared the performances of two optical interferometers with different characteristics when applied to measurement of pulsed thermoelastic waves. The surface displacement-tracking system was designed to measure the center of the microscopic view. A pulsed laser beam irradiated a black ink layer to generate the thermoelastic waves. The out-of-plane displacement on the axially opposite side was then measured using either a Michelson interferometer or a Sagnac interferometer. The objective lens of the system was of a type commonly used in biological observations. The Michelson interferometer estimated a maximum displacement of 0.43 nm and a maximum sound pressure of 24.7 kPa. The signal-to-noise ratios from 16 averages were 14.9 dB (Michelson interferometer) and 19.2 dB (Sagnac interferometer). Furthermore, this paper compares the performance of the numerically estimated Sagnac interferometer outputs calculated from the measured Michelson interferometer outputs with the experimentally obtained Sagnac interferometer outputs. The numerically estimated Sagnac interferometer's output was shown to be identical to the experimentally acquired output. The Michelson interferometer requires a higher average operating frequency (i.e., it needs a longer data acquisition time), although this interferometer does offer superior displacement output linearity. This property enables calculation of the sound pressure from the displacement amplitude. These findings indicated that combination of the measurement points of the Sagnac interferometer with those of the sparsely distributed Michelson interferometer reduced the measurement time when compared with a single use of the Michelson interferometer while also maintaining the data acquisition quality.

Detection of Individual Microbubbles by Burst-Wave-Aided Contrast-Enhanced Active Doppler Ultrasonography.

We propose burst-wave-aided, contrast-enhanced, active Doppler ultrasonography for visualizing lymph vessels. This technique forces ultrasound contrast agents (UCAs) to move using the acoustic radiation force induced by burst waves with low amplitude while suppressing their destruction. Using a flow phantom, we measured the average, decrease rate of echo intensity [i.e., pulse intensity integral (PII)], and the velocity of individual contrast agents, which directly affects the performance of imaging and tracking contrast agents under stationary flow conditions. Comparison with pulse-inversion Doppler without exposure to the burst wave demonstrated that the velocity of the contrast agents could be enhanced up to several tens of millimeters per second by the effect of the burst wave, maximizing the echo intensity extracted by a clutter filter. The contrast ratio (CR), defined as the ratio of the contrast echo to the phantom echo outside the channel, did not change appreciably, even when the lower cut-off velocity of the clutter filter was increased up to 10 mm/s. This implies a better robustness against the motion of the tissue. In addition, the performance for detecting contrast agents (i.e., echo intensity) was superior or similar to that of pulse-inversion Doppler, even in undesirable conditions where the flow had a velocity component in the opposite direction to that of the acoustic radiation force. The echo intensity was lower or the same as that in pulse-inversion Doppler, demonstrating the potential for suppressing the destruction of contrast agents and enabling long-term observations. From these results, we expect that the proposed method will be beneficial for visualizing lymph vessels.

Impact of Accessory Renal Artery Embolization on Renal Deterioration Under Endovascular Aortic Repair.

OBJECTIVE: The optimal management strategy for patients with accessory renal arteries undergoing endovascular aortic repair is unclear. This study aimed to investigate the impact of accessory renal artery (aRA) embolization on postoperative renal deterioration and to identify the predictors of postoperative renal deterioration in patients who underwent endovascular aortic repair (EVAR). METHODS: A retrospective single-centre observational study was conducted at our hospital. Of 331 consecutive patients who underwent endovascular aortic repair between April 2011 and February 2021, 29 patients with an aRA were included in this study. Spearman's rank correlation coefficients of decrease in estimated glomerular filtration rate (eGFR), renal volume reduction rate, infarcted renal volume, and quantity of contrast use for postoperative renal deterioration were analyzed. The correlation coefficients of the correlations between infarcted renal volume, renal volume reduction rate, and decrease in eGFR and the rate of aRA diameter were also analyzed. Multivariable nominal logistic regression analyses were conducted to evaluate the odds of postoperative renal deterioration. RESULTS: The renal volume reduction rate and infarcted renal volume had a significant positive correlation with the decrease in eGFR. Body surface area and preoperative renal volume were significantly but negatively correlated with the decrease in eGFR. The infarcted renal volume, renal volume reduction rate, and decrease in eGFR were significantly and positively correlated with the aRA diameter. The odds ratio for decreased eGFR rate in preoperative renal volume was .96 (95% CI 0.930‒.996, P = .009). CONCLUSIONS: EVAR with aRA embolization impacts postoperative renal deterioration in patients with preoperative low renal volume, and the diameter of the embolized aRA might be a predictor of postoperative renal deterioration.

The Effect of Steatosis on Shear-Wave Velocity and Viscoelastic Properties Related to Liver Fibrosis Progression in Rat Models.

OBJECTIVE: Hepatic fibrosis has recently been evaluated using ultrasonography or magnetic resonance elastography. Although the shear wave velocity (SWV) obtained using point shear wave elastography (pSWE) provides a valuable measure of fibrosis, underlying steatosis may affect its measurement. METHODS: Using hepatic fibrosis samples, this study evaluated the effect of steatosis on the shear wave velocity of pSWE (Vs) and viscoelastic properties (assessed by dynamic mechanical analysis) of rat liver. Fifty rats with various grades of steatosis and fibrosis underwent open abdominal in vivo Vs measurements using a commercial ultrasound scanner. The mechanical properties of hepatic tissue were also characterized under ex vivo conditions using dynamic mechanical analysis and the Zener model of viscoelasticity. RESULTS: Fibrosis and steatosis progression influenced Vs and elasticity. The SWV computed using the Zener model and Vs showed a substantial correlation (r > 0.8). Fibrosis progression increased SWV. Steatosis was also related to SWV. Steatosis progression obscured the SWV change associated with fibrosis progression. CONCLUSION: We conclude that steatosis progression affects the evaluation of fibrosis progression. This finding could aid discrimination of non-alcoholic steatohepatitis from non-alcoholic fatty liver disease using SWV.

Modified multi-Rayleigh model-based statistical analysis of ultrasound envelope for quantification of liver steatosis and fibrosis.

PURPOSE: Quantitative diagnosis of the degree of fibrosis progression is currently a focus of attention for fatty liver in nonalcoholic steatohepatitis (NASH). However, previous studies have focused on either lipid droplets or fibrotic tissue, and few have reported the evaluation of both in patients whose livers contain adipose and fibrous features. Our aim was to evaluate fibrosis tissue and lipid droplets in the liver. METHODS: We used an analytical method combining the multi-Rayleigh (MRA) model and a healthy liver structure filter (HLSF) as a technique for statistical analysis of the amplitude envelope to estimate fat and fibrotic volumes in clinical datasets with different degrees of fat and fibrosis progression. RESULTS: Fat mass was estimated based on the non-MRA fraction corresponding to the signal characteristics of aggregated lipid droplets. Non-MRA fraction has a positive correlation with fat mass and is effective for detecting moderate and severe fatty livers. Progression of fibrosis was estimated using MRA parameters in combination with the HLSF. The proposed method was used to extract non-healthy areas with characteristics of fibrotic tissue. Fibrosis in early fatty liver suggested the possibility of evaluation. On the other hand, fat was identified as a factor that reduced the accuracy of estimating fibrosis progression in moderate and severe fatty livers. CONCLUSION: The proposed method was used to simultaneously evaluate fat mass and fibrosis progression in early fatty liver, suggesting the possibility of quantitative evaluation for discriminating between lipid droplets and fibrous tissue in the early fatty liver.

Lower extremity artery thromboembolism during removal of Impella after repair for ventricular septal rupture: A case report.

Although the anticoagulant complications of Impella are well known, the timing of heparin administration when using Impella immediately after open heart surgery has not been established. We report a case of a 59-year-old man with Impella-assisted repair of a ventricular septal perforation after acute myocardial infarction who developed thromboembolism of the lower extremity arteries after removal of Impella.

Reversed L-shaped incision for resection of a large azygos vein aneurysm: a case report.

BACKGROUND: Azygos vein aneurysms are rare and asymptomatic in many cases. The management for these aneurysms is controversial, and there is no clear guideline or evidence-based threshold for surgical or interventional therapy. CASE PRESENTATION: Herein, we report the case of a giant azygos vein aneurysm in a 78-year-old man that was treated with a reversed L-shaped incision. A 56 × 77 mm saccular azygos vein aneurysm was incidentally detected on computed tomography. Subsequently, surgical resection with interventional radiology and reversed L-shaped thoracotomy was performed. First, we performed coil embolization of the azygos vein aneurysm inflow. Next, a cardiopulmonary bypass was established through a reversed L-shaped sternotomy, and the aneurysm was excised. CONCLUSIONS: In this case, surgical resection via reversed L incision was effective.

Safety Measures for Maintaining Low Endophthalmitis Rate after Intravitreal Anti-Vascular Endothelial Growth Factor Injection before and during the COVID-19 Pandemic.

During the COVID-19 pandemic, intravitreal injections are performed with patients wearing masks. The risk of endophthalmitis after intravitreal injection is reported to increase due to an influx of exhaled air containing oral bacteria from the upper part of the mask onto the ocular surface. We retrospectively investigated the incidence of endophthalmitis when intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections were performed using the same infection control measures before and during the pandemic. Vitreoretinal specialists performed intravitreal injections of anti-VEGF agents in the outpatient room of a university hospital. Infection control measures before and during the pandemic included covering the patient's eye with adhesive face drape and irrigating the ocular surface with 0.25% povidone-iodine before draping, and immediately before and after injection. Before the COVID-19 pandemic (February 2016 to December 2019), one case of endophthalmitis occurred among 31,173 injections performed (0.0032%; 95% confidence interval (CI), 0.000008-0.017872%). During the COVID-19 pandemic (January 2020 to August 2021), one case of endophthalmitis occurred among 14,725 injections performed (0.0068%; 95% CI, 0.000017-0.037832%). There was no significant difference between the two periods (Fisher's exact test: p = 0.5387). Even during the COVID-19 pandemic, very low incidence of endophthalmitis after intravitreal injection can be maintained by implementing basic infection prophylactic measures, including face draping and 0.25% povidone-iodine irrigation, established before COVID-19 pandemic.

Hemolytic anemia caused by kinked graft 6 months after aortic dissection repair.

BACKGROUND: Clinically insignificant hemolytic anemia is occasionally a complication of prosthetic valve replacement. However, hemolysis related to kinked grafts is a very rare complication after central repair for acute aortic dissection. CASE PRESENTATION: A 42-year-old man had undergone replacement of the ascending aorta and a root repair for type A aortic dissection 6 months previously. Laboratory data showed mild hemolysis 5 months later, and he began to complain of fatigue on exertion. The serum hemoglobin level reduced to 8.6 g/dL, and lactate dehydrogenase levels increased to 3071 IU/L with gross change in urine color, indicating hemoglobinuria. We diagnosed mechanical hemolytic anemia caused by a kinked graft and planned a repeat operation. The kinked graft was resected and graft-graft anastomosis was performed. Postoperatively, the clinical course was uneventful, and the hemolytic anemia completely resolved. CONCLUSION: We herein report a case of hemolytic anemia caused by kinking of the graft 6 months after acute aortic dissection repair. The diagnosis was swiftly made, and the patient was successfully managed with redo surgery.