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result(s) for
"Imai, Akito"
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Iron imaging in myocardial infarction reperfusion injury
by
Imai, Akito
,
Tschabrunn, Cory
,
Kumar, Rishabh
in
59/57
,
631/1647/245/1628
,
692/4019/592/75/2/1674
2020
Restoration of coronary blood flow after a heart attack can cause reperfusion injury potentially leading to impaired cardiac function, adverse tissue remodeling and heart failure. Iron is an essential biometal that may have a pathologic role in this process. There is a clinical need for a precise noninvasive method to detect iron for risk stratification of patients and therapy evaluation. Here, we report that magnetic susceptibility imaging in a large animal model shows an infarct paramagnetic shift associated with duration of coronary artery occlusion and the presence of iron. Iron validation techniques used include histology, immunohistochemistry, spectrometry and spectroscopy. Further mRNA analysis shows upregulation of ferritin and heme oxygenase. While conventional imaging corroborates the findings of iron deposition, magnetic susceptibility imaging has improved sensitivity to iron and mitigates confounding factors such as edema and fibrosis. Myocardial infarction patients receiving reperfusion therapy show magnetic susceptibility changes associated with hypokinetic myocardial wall motion and microvascular obstruction, demonstrating potential for clinical translation.
Restoration of coronary blood flow after a heart attack may lead to reperfusion injury and pathologic iron deposition. Here, the authors perform magnetic susceptibility imaging showing its association with iron in a large animal model of myocardial infarction during wound healing, and showing feasibility in acute myocardial infarction patients undergoing percutaneous coronary intervention.
Journal Article
Radical surgery for a mitral valve intimal sarcoma: serial patch repair of the annulus and atrium
by
Mitomi, Kisato
,
Imai, Akito
,
Matsuzaki, Kanji
in
Case reports
,
Gene amplification
,
Heart surgery
2022
We report the rare case of a 48-year-old woman with a cardiac intimal sarcoma occupying the mitral valve and the left atrial roof. We resected the tumour in one block without residual lesions. The anterior mitral annulus and left atrial roof were serially repaired with the bovine pericardium, and a mechanical prosthesis was implanted in the reconstructed mitral annulus. The patient remains alive without recurrence for more than 1 and a half years postoperatively. We performed radical surgery for a mitral valve intimal sarcoma, and serial patch repair of the anterior mitral annulus and left atrial roof was a useful technique.
Journal Article
Aortic valve area index values of Trifecta implants correlate with energy loss and increased valve stress
2025
Biological valves are becoming more frequently used in aortic valve replacement. While several reports have evaluated the performance of biological valves, echocardiography studies during exercise stress remain scarce. Furthermore, no current reports compare rate changes in the aortic valve area of biological valves under increased exercise load. Here, we performed exercise stress echocardiography in patients after AVR with Trifecta or Inspiris valves and compared the rates of change in aortic valve areas (AVA). In addition, hydrodynamic analysis at rest was conducted with four-dimensional flow magnetic resonance imaging (4D-flow MRI). Exercise stress echocardiography was performed in seven Trifecta and seven Inspiris patients who underwent AVR at our hospital while 4D flow MRI was performed in all but two Trifecta cases. Comparing the percentage change in AVA when loaded to 25 W versus at rest, Trifecta was greater than Inspiris (28.7 ± 36.0 vs − 0.8 ± 12.4%). The smaller AVA at rest was considered causative for this. Meanwhile, Trifecta systolic energy loss in the prosthetic valve segment on 4D-flow MRI (97.5 ± 35.9 vs 52.7 ± 25.3 mW) was higher than Inspiris. The opening of the Trifecta valve was considered to be restricted at rest and this may reflect the current reports of early valve degradation requiring reoperation. Taken together, we observed that the Trifecta design may promote faster wear due to higher valve stress.
Journal Article
Y-shaped graft replacement of an isolated innominate artery aneurysm via the transmanubrial approach
2024
Abstract
We report the rare case of an obese woman with a 32-mm isolated innominate artery aneurysm. Due to the deep location of the aneurysm within the thoracic inlet, we selected a transmanubrial osteomuscular sparing approach to obtain a clear field of vision. During the aneurysmectomy and reconstruction with a Y-shaped graft, we performed a temporary bypass using a contralateral leg of the graft to the right common carotid artery. Through these techniques, we successfully achieved complete resection and reconstruction of the aneurysm without the need for cardiopulmonary bypass.
Isolated innominate artery aneurysms (IAAs) without aortic lesions are rare [1, 2].
Journal Article
Pulmonary artery sarcoma and severe valvular diseases in late-septuagenarian women: was 2-stage surgery an appropriate strategy? A case report
2024
Background
Pulmonary artery sarcomas (PASs) are rare, and complete tumor resection is often difficult at the time of detection. We encountered a case of PAS that was thought to be resectable; however, the patient had severe symptomatic valvular disease. We faced a difficult decision regarding the surgical strategy.
Case presentation
A 76-year-old female presented with a history of polysurgery for multiple primary cancers. She was referred to our department with a calcified mass in the right pulmonary artery (PA) and severe symptomatic valvular disease. After a discussion with the cardiovascular surgeon, we decided to perform a two-stage surgery. She underwent valvuloplasty through a median sternotomy, resulting in an improvement in her exertional dyspnea. The tumor was removed three months later with a right upper lobectomy and PA patch reconstruction through a posterolateral thoracotomy. When the PA was opened, the edge of the tumor was entrapped by vascular clamp forceps because of insufficient dissection of the adhesions between the superior vena cava and the right main PA resulting from the first operation. The patient underwent proton therapy twice for chest wall metastases which recurred three months after surgery, and local recurrence in the PA was diagnosed five months after surgery. The patient was alive with stable disease 25 months after surgery.
Conclusion
Two-stage surgery for PAS and valvular disease resulted in incomplete resection of the PAS in the right PA. It is important not to underestimate surgical adhesions due to the initial surgery and to consider and implement measures to prevent adhesions of critical vessels during the second operation.
Journal Article
Modified Commando procedure using a double valve composite through an aorto-annulo-septotomy
by
Kisato Mitomi
,
Yasunori Watanabe
,
Akito Imai
in
Coronary vessels
,
Debridement
,
Digital video recorders
2024
Abstract
Double valve replacement of aortic and mitral valves with intervalvular fibrous body reconstruction (Commando procedure) is a challenging operation. Particularly in redo surgery for prosthetic valve endocarditis, special techniques are needed for approaching and reconstructing the valve complex. We performed a modified Commando procedure using a double valve composite through an aorto-annulo-septotomy. This approach provided a good field of vision at the combined aortic and mitral annuli without incising the left atrial roof. The double valve composite with four-layer patch wings was useful for performing double valve replacement en bloc and aorto-annulo-septotomy closure serially. Using these techniques, we successfully performed the Commando procedure for complicated prosthetic valve endocarditis.
The Commando procedure is a challenging operation consisting of double valve replacement (DVR) of aortic and mitral valves with intervalvular fibrous body (IFB) reconstruction [1, 2].
Journal Article
Aortic annular enlargement techniques using an original patch for prosthetic valve endocarditis
2020
Background
Prosthetic valve endocarditis (PVE) is a serious complication, and it is difficult to treat marked adhesion and infectious tissue.
Case presentation
There were four patients with aortic PVE, whose ages ranged from 59 to 80 years. In all patients, transoesophageal echocardiography revealed periannular abscess formation. We applied aortic annular enlargement techniques using a composite three-layer patch to repair the defects after radical debridement of the abscesses, and then replaced the prosthetic valves on the reconstructed annuli. All patients received antibiotics after surgery and recovered well without recurrence.
Conclusions
The aortic annular enlargement techniques provided a good field of vision at the complicated annulus, and our original patch was useful for repairing the aortic annulus and its surrounding apparatus.
Journal Article
Combined treatment for a large primary cardiac sarcoma: a case report
by
Akishima, Shinji
,
Enomoto, Yoshiharu
,
Imai, Akito
in
Acute heart failure
,
Cancer therapies
,
Case Report
2019
Background
Undifferentiated pleomorphic sarcoma (UPS) as a primary cardiac tumor is rare, with extremely poor prognosis owing to high recurrence and invasion. We encountered a patient who presented with a primary cardiac tumor incarcerating the mitral valve and who was in a shock state.
Case presentation
A 41-year-old man was transported emergently to our hospital owing to acute respiratory distress and hemoptysis. He was diagnosed with acute left heart failure caused by a large mass in the left atrium (LA) that obstructed cardiac blood flow, as revealed by imaging study findings, and he underwent an emergency open-heart surgery for tumor resection. He was pathologically diagnosed with UPS invading the muscle layer of the LA. However, after receiving combined therapy for local recurrence and distant metastasis, including proton beam radiotherapy and chemotherapy with molecularly targeted drugs, he could return to work for 2 more years after surgery.
Conclusion
In this study, we reported the case of a patient who was in a state of shock state owing to the presence of UPS in the LA. The patient underwent an emergency surgery and received combined therapy. He survived for 2 more years after an initial diagnosis, without active local recurrence and distant metastasis.
Journal Article
Left atrial geometry in an ovine ischemic mitral regurgitation model: implications for transcatheter mitral valve replacement devices with a left atrial anchoring mechanism
by
Gorman, Joseph H.
,
Imai, Akito
,
Gillespie, Matthew J.
in
(Transcatheter) mitral valve replacement ((T)MVR)
,
Animals
,
Aorta
2021
Background
Transcatheter mitral valve replacement (TMVR) is a challenging, but promising minimally invasive treatment option for patients with mitral valve disease. Depending on the anchoring mechanism, complications such as mitral leaflet or chordal disruption, aortic valve disruption or left ventricular outflow tract obstruction may occur. Supra-annular devices only anchor at the left atrial (LA) level with a low risk of these complications. For development of transcatheter valves based on LA anchoring, animal feasibility studies are required. In this study we sought to describe LA systolic and diastolic geometry in an ovine ischemic mitral regurgitation (IMR) model using magnetic resonance imaging (MRI) and echocardiography in order to facilitate future research focusing on TMVR device development for (I)MR with LA anchoring mechanisms.
Methods
A group of 10 adult male Dorsett sheep underwent a left lateral thoracotomy. Posterolateral myocardial infarction was created by ligation of the left circumflex coronary artery, the obtuse marginal and diagonal branches. MRI and echocardiography were performed at baseline and 8 weeks after myocardial infarction (MI).
Results
Six animals survived to 8 weeks follow-up. All animals had grade 2 + or higher IMR 8 weeks post-MI. All LA geometric parameters did not change significantly 8 weeks post-MI compared to baseline. Diastolic and systolic interpapillary muscle distance increased significantly 8 weeks post-MI.
Conclusions
Systolic and diastolic LA geometry do not change significantly in the presence of grade 2 + or higher IMR 8 weeks post-MI. These findings help facilitate future tailored TMVR device development with LA anchoring mechanisms.
Journal Article
Cryoablation in Redo Surgery for a Recurrent Intimal Sarcoma of the Left Atrium
by
Imai, Akito
,
Matsuzaki, Kanji
,
Watanabe, Yasunori
in
Cryosurgery
,
Female
,
Heart Atria - diagnostic imaging
2026
Abstract
Objectives: We report a rare case of a 52-year-old woman with a recurrent intimal sarcoma adjacent to the mitral prosthesis in the left atrium. She had previously undergone initial surgery for mitral valve intimal sarcoma at age 48.
Methods: At this presentation, we resected a 25-mm tumour as well as the surrounding lesions. Cryoablation was applied using cryoICE on all resection margins and the posterior mitral annulus.
Results: The use of a malleable probe facilitated the redo surgery. The patient has remained alive for more than 5 years following the initial operation and for 11 months after the subsequent redo surgery.
Conclusion: Cryoablation may play an important role in improving surgical radicality in cardiac sarcoma.
Primary cardiac intimal sarcoma is an exceptionally rare but lethal malignancy originating from intimal subendothelial cells.
Journal Article