Yoshinori Kuroda

In vivo visualization of redox status by high-resolution whole body magnetic resonance imaging using nitroxide radicals

Various diseases are known to be associated with an imbalance of the redox state, but in vivo detection of free radicals is difficult. The purpose of this study is to establish a method for in vivo visualization of redox status by high-resolution whole-body MRI using nitroxide radicals. A redox-sensitive nitroxide probe, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (carbamoyl-PROXYL), was administered to rats intravenously, and in vivo T1-weighted MRI was performed to virtually visualize the redox status of various organs. In experiments using phantoms, a linear relationship between the MRI signal and the carbamoyl-PROXYL concentration persisted up to 80 mM. Among the phantoms, a sample containing 1 mM carbamoyl-PROXYL was readily identifiable. After intravenous injection of carbamoyl-PROXYL, whole-body T1-weighted MRI of the rat provided clear images with good spatial and temporal resolution. The signal intensities of four selected organs (heart, liver, kidney, and intestine) were analyzed quantitatively. The carbamoyl-PROXYL signal peaked and gradually declined due to reduction after intravenous injection. Among the four organs, the organ-specific reduction rate of carbamoyl-PROXYL was highest in the heart, followed by (in order) the liver, kidney, and intestine, and statistical analysis showed that the inter-organ differences were significant. In conclusion, T1-weighted carbamoyl-PROXYL-enhanced MRI provides excellent spatial and temporal imaging of carbamoyl-PROXYL distribution. Furthermore, it provides important functional information pertaining to blood flow and tissue redox activity in individual organs. MRI in combination with carbamoyl-PROXYL has potential clinical application for evaluation of redox activity in whole organs.

An intra-aortic floating metastatic malignancy of unknown primary origin

A 69-year-old man with sudden strong back pain was transported to our hospital by ambulance. The computed tomography scan revealed an intra-aortic floating mass with a stalk arising from the descending aortic wall, which was thought to be a thrombus. The floating mass displayed the characteristics of a thrombus rather than a neoplastic tumour on magnetic resonance imaging scan. Under extracorporeal circulation, the descending aorta was cut open, and the mass was resected. Subsequently, a stent graft was placed to cover the abnormal aortic intima to prevent recurrent thrombus formation. The pathological diagnosis revealed an adenocarcinoma, not a thrombus. We could not detect the origin of malignancy despite additional examinations. Brain metastasis developed, and the patient died of recurrent pneumonia and urinary tract infection. These findings emphasize the importance of a precise plan of action for rare diseases.

Novel Surgical Technique for Coronary Fistulas With Proximal Origin

Postoperative residual shunting is a significant concern in patients with coronary arteriovenous fistulas, especially in fistulas originating from the proximal left coronary artery, because of the limited surgical field. We report a case of fistulas originating from the proximal coronary artery in a 63-year-old woman in whom the ascending aorta and pulmonary artery were transected to obtain good surgical exposure. After complete transection of both great arteries, fistulas arising from the left main trunk were ligated externally, and their intracardiac openings were closed internally. Postoperative examination revealed no residual shunt flow.

Takotsubo Cardiomyopathy after Hybrid Repair of Thoracic andThoracoabdominal Aortic Aneurysm

Context: Takotsubo cardiomyopathy is characterized by transient and acute left ventricular dysfunction with apical dyskinesia in the absence of coronary artery disease. The pathophysiology of this rare disease is considered to be associated with physical and psychological stress. Recently published case reports have described the association between Takotsubo syndrome and various surgical procedures as the causative stress factors. However, Takotsubo cardiomyopathy is extremely rare in patients who have undergone cardiovascular surgery. Case report: Here, we report a rare case of Takotsubo cardiomyopathy developing after thoracic endovascular aortic repair for chronic dissecting aortic aneurysm. Conclusion: This patient developed Takotsubo cardiomyopathy 14 days after thoracic endovascular aortic repair, potentially because of the prolonged perioperative physical and psychological stress induced by multi-stage surgery. To our knowledge, this is the first report of Takotsubo cardiomyopathy after thoracic endovascular aortic repair. Through this report, we emphasize the importance of considering the possibility of Takotsubo cardiomyopathy in patients presenting symptoms of cardiogenic shock and unexplained hemodynamic deterioration, despite having undergone relatively less-invasive cardiovascular surgery. Early diagnosis is required to initiate appropriate treatment and to minimize the chance of complications.

Surgical repair of a celiac artery aneurysm using a sutureless proximal anastomosis device

Some celiac artery aneurysms are not suitable for endovascular therapy. We describe the case of a 63-year-old man with a celiac trunk aneurysm extending to the hepatosplenic bifurcation. The aneurysm was resected and oversewn at the origin from the abdominal aorta. A saphenous vein bypass from the supraceliac aorta to the celiac artery bifurcation was performed using a sutureless anastomotic device (PAS-Port system; Cardica, Redwood City, Calif) to create the proximal anastomosis, eliminating the need for aortic clamping. This system is thought to make direct proximal aortic anastomosis safe and easy in patients requiring surgical reconstruction of celiac artery aneurysms.

Immunoglobulin G Subclass 4-Related Lymphoplasmacytic Thoracic Aortitis in a Patient with Acute Type A Aortic Dissection

Immunoglobulin G subclass 4-related disease (IgG4-RD) is a recently recognized systemic inflammatory disease characterized by an elevated serum IgG4 level and an IgG4-positive lymphocyte infiltrate mainly in exocrine tissues. Previous reports documented IgG4-RD in several cardiovascular disorders. We present a case of type A aortic dissection associated with IgG4-RD. A 52-year-old man diagnosed with a type A aortic dissection was referred for surgical treatment. He underwent emergency hemiarch reconstruction with a prosthetic graft. His postoperative recovery was uncomplicated. Histopathologic examination of his aortic tissue showed marked adventitial thickening with fibrosis and an IgG4-positive plasma cell infiltrate. He was diagnosed with type A aortic dissection incidentally complicated by IgG4-RD. The relationship between IgG4-RD and the pathogenesis of aortic dissection remains unknown and requires further investigation.