Fenestrated Fontan-like circulation under durable left-ventricular assist device support in fulminant myocarditis.

Fulminant myocarditis is a fatal development from profound biventricular heart failure and often requires both right- and left-ventricular assistance to maintain hemodynamics, even at the risk of increased mortality and morbidity. Here, we present a 42-year-old female with profound biventricular failure due to fulminant myocarditis, resolved by an isolated durable left-ventricular assist device support under a fenestrated, Fontan-like circulation and managed low-pulmonary vascular resistance.

Surgical outcomes of bridge-to-bridge therapy with extracorporeal left ventricular assist device for acute myocardial infarction in cardiogenic shock.

BACKGROUND: Extracorporeal left ventricular assist device is often required for acute myocardial infarction patients in cardiogenic shock when temporary mechanical circulatory support fails to provide hemodynamic stabilization. This study aimed to evaluate the clinical outcomes of acute myocardial infarction patients in cardiogenic shock supported by an extracorporeal left ventricular assist device. METHODS: This retrospective study enrolled 13 acute myocardial infarction patients in cardiogenic shock treated with an extracorporeal left ventricular assist device from April 2011 to July 2020. RESULTS: Twelve (92.3%) and eleven (84.6%) patients were supported using venoarterial extracorporeal membrane oxygenation and intra-aortic balloon pumping before implantation, respectively. The median duration from acute myocardial infarction to extracorporeal left ventricular assist device implantation was 7 (3.5-24.5) days. The overall in-hospital mortality rate was 30.8% (n = 4). Extracorporeal left ventricular assist device was explanted in one patient for cardiac recovery; eight (61.5%) patients were approved as heart transplant candidates in whom the extracorporeal left ventricular assist device was exchanged for a durable left ventricular assist device; two (15.4%) expired while waiting for a heart transplant, and two (15.4%) received a successful transplant. The 1- and 3-year overall survival rates after extracorporeal left ventricular assist device implantation were 68.3% and 49.9%, respectively. CONCLUSIONS: The operative mortality after extracorporeal left ventricular assist device implantation in acute myocardial infarction patients in cardiogenic shock was favorable. Our strategy of early hemodynamic stabilization with extracorporeal left ventricular assist device implantation in these patients as a bridge-to-bridge therapy was effective in achieving better survival.

Validity of Ipsilateral Internal Mammary Coronary Artery Bypass Graft of Arteriovenous Fistula.

BACKGROUND: In coronary artery bypass grafting (CABG) for haemodialysis patients, arteriovenous fistula can reduce blood flow from the internal mammary artery (IMA) graft. The purpose of this study was to delineate the rationale of ipsilateral IMA grafting to the arteriovenous fistula by assessing graft flow and patency. METHOD: The clinical records of 139 haemodialysis patients who underwent off-pump CABG, including IMA grafting to the left anterior descending artery (LAD) between April 2007 and December 2018, were retrospectively reviewed. Clinical outcomes and transit-time flowmetry results of IMA to LAD bypass grafts during off-pump CABG and postoperative angiography were examined. RESULTS: An ipsilateral IMA to the arteriovenous fistula (Ipsi-IMA) was used in 89 patients, and a contralateral IMA to the arteriovenous fistula (Contra-IMA) was used in 50 patients and no hospital deaths occurred. The mean graft flow and angiographic patency rate did not differ between the Ipsi-IMA and Contra-IMA groups. In patients with 51 to 90% stenosis of LAD, there was no significant difference in the mean graft flow. In comparison, in the patients with 91 to 100% stenosis of LAD, the mean graft flow in the Ipsi-IMA group was significantly lower than that in the Contra-IMA group (p=0.03). Kaplan-Meier analyses showed a 5-year survival rate of 57.6% for Ipsi-IMA and 64.8% for Contra-IMA (p=0.47). CONCLUSIONS: In the revascularisation of the LAD, the graft patency rate of the Ipsi-IMA was not inferior to that of the Contra-IMA. However, when the LAD has 91 to 100% stenosis, a Contra-IMA to arteriovenous fistula may be beneficial in terms of sufficient flow capacity.

An autopsy case of aortic dissection due to giant cell arteritis.

Giant cell arteritis (GCA) is a systemic vasculitis affecting mainly large and medium-sized arteries. GCA sometimes involves the aorta and its major branches and causes aortic dissection as a rare complication. We have experienced an autopsy case of aortic dissection due to GCA. The patient was an 87-year-old Japanese woman with Stanford type A aortic dissection who died 7 days after admission. Two years previously she had been diagnosed as having abdominal aortic aneurysm and undergone endovascular aneurysm repair (EVAR). Although she had no characteristic symptoms of GCA, autopsy revealed marked granulomatous inflammation in the dissected area and coronary arteries. Active arteritis was evident not only in the arteries of the upper extremity but also those in the lower extremity. Granulomatous inflammation was not evident in the aneurysm. The aortic dissection might have been an initial manifestation of GCA. We report the regions of GCA extension and its histology in detail.

Early and mid-term results of transcatheter aortic valve implantation and valve durability assessment.

This study aimed to evaluate the early and mid-term outcomes of transcatheter aortic valve implantation (TAVI) and to assess valve durability. A total of 146 consecutive patients who underwent TAVI for severe aortic stenosis between October 2013 and August 2018 were retrospectively reviewed. All patients (mean age, 84 ± 6 years; age range 53-98 years; 42 males [28.7%]) had multiple comorbidities, with a mean logistic EuroSCORE of 30.9 ± 17.4%. Eighteen patients (12.3%) were aged 90 years or over. Five in-hospital deaths (3.4%) occurred, and 36 patients (24.7%) experienced major TAVI-related complications. With the transfemoral approach, 10 patients had major vascular complications, which mostly occurred with first-generation devices (n = 9) but less commonly with new-generation low-profile devices (P = 0.0078). During a follow-up period of 580 ± 450 (11-1738) days, 29 late deaths occurred. The survival rate was 86.0%, 78.0%, and 61.7% at 1, 2, and 3 years, respectively. Multivariate Cox hazard regression analysis revealed that more-than-moderate tricuspid regurgitation was the only independent risk factor for late deaths due to any cause (hazard ratio, 3.145; 95% confidence interval, 1.129-8.762; P = 0.0283). No statistically significant differences between post-TAVI before discharge from the hospital and at 4 years after TAVI were observed with respect to aortic valve area (1.76 ± 0.49 cm2 vs. 1.64 ± 0.38 cm2; P = 0.1871) and mean pressure gradient (10.0 ± 4.6 mmHg vs. 7.9 ± 3.3 mmHg; P = 0.5032). TAVI was a feasible method with acceptable early and mid-term outcomes and valve durability for at least 4 years in poor-risk patients. Further close follow-up is essential to evaluate late outcomes and valve durability.

Role of Thrombospondin-1 in Mechanotransduction and Development of Thoracic Aortic Aneurysm in Mouse and Humans.

RATIONALE: Abnormal mechanosensing of smooth muscle cells (SMCs) resulting from the defective elastin-contractile units has been suggested to drive the formation of thoracic aortic aneurysms; however, the precise molecular mechanism has not been elucidated. OBJECTIVE: The aim of this study was to identify the crucial mediator(s) involved in abnormal mechanosensing and propagation of biochemical signals during the aneurysm formation and to establish a basis for a novel therapeutic strategy. METHODS AND RESULTS: We used a mouse model of postnatal ascending aortic aneurysms ( Fbln4SMKO; termed SMKO [SMC-specific knockout]), in which deletion of Fbln4 (fibulin-4) leads to disruption of the elastin-contractile units caused by a loss of elastic lamina-SMC connections. In this mouse, upregulation of Egr1 (early growth response 1) and angiotensin-converting enzyme leads to activation of Ang II (angiotensin II) signaling. Here, we showed that the matricellular protein, Thbs1 (thrombospondin-1), was highly upregulated in SMKO ascending aortas and in human thoracic aortic aneurysms. Thbs1 was induced by mechanical stretch and Ang II in SMCs, for which Egr1 was required, and reduction of Fbln4 sensitized the cells to these stimuli and led to higher expression of Egr1 and Thbs1. Deletion of Thbs1 in SMKO mice prevented the aneurysm formation in ≈80% of DKO (SMKO;Thbs1 knockout) animals and suppressed Ssh1 (slingshot-1) and cofilin dephosphorylation, leading to the formation of normal actin filaments. Furthermore, elastic lamina-SMC connections were restored in DKO aortas, and mechanical testing showed that structural and material properties of DKO aortas were markedly improved. CONCLUSIONS: Thbs1 is a critical component of mechanotransduction, as well as a modulator of elastic fiber organization. Maladaptive upregulation of Thbs1 results in disruption of elastin-contractile units and dysregulation of actin cytoskeletal remodeling, contributing to the development of ascending aortic aneurysms in vivo. Thbs1 may serve as a potential therapeutic target for treating thoracic aortic aneurysms.

Aging impairs beige adipocyte differentiation of mesenchymal stem cells via the reduced expression of Sirtuin 1.

In the body, different types of adipose tissue perform different functions, with brown and beige adipose tissues playing unique roles in dissipating energy. Throughout life, adipocytes are regenerated from progenitors, and this process is impaired by aging. One of the progenitors of adipocytes are mesenchymal stem cells (MSCs), which have recently become a promising tool for stem cell therapy. However, whether or not aging impairs the brown/beige adipocyte differentiation of adipose tissue-derived MSCs (AT-MSCs) remains unclear. In the present study, we isolated AT-MSCs from two different age groups of donors (infants and elderly subjects) and examined the effects of aging on the AT-MSC brown/beige adipocyte differentiation ability. We found that none of the AT-MSCs expressed Myf5, which indicated the beige (not brown) differentiation ability of cells. Of note, an inverse correlation was noted between the beige adipocyte differentiation ability and age, with AT-MSCs derived from elderly donors showed the most severely reduced function due to induced cellular senescence. The impaired expression of Sirtuin 1 (Sirt1) and Sirt3 proved to be responsible for the induction of senescence in elderly AT-MSCs; however, only Sirt1 was directly involved in the regulation of beige adipocyte differentiation. The overexpression of Sirt1 impaired the p53/p21 pathway, thereby preventing elderly AT-MSCs from entering senescence and restoring the beige differentiation ability. Thus, our study represents the important role of Sirt1 and senescence in the regulation of beige adipocyte differentiation during aging.

Landiolol Hydrochloride Rapidly Controls Junctional Ectopic Tachycardia After Pediatric Heart Surgery.

OBJECTIVES: Junctional ectopic tachycardia is a supraventricular tachyarrhythmia with atrioventricular dissociation that causes life-threatening postsurgical conditions in pediatric heart patients. This study evaluates the efficacy of landiolol hydrochloride for managing junctional ectopic tachycardia. DESIGN: A single-center retrospective study. SETTING: PICU at the university hospital. PATIENTS: Of 561 pediatric patients who underwent open-heart surgery between 2006 and 2017, 10 patients developed sustained junctional ectopic tachycardia and were selected for landiolol treatment. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Landiolol decreased mean heart rate significantly from 206.1 ± 14.5 to 158.0 ± 8.6 beats/min within 2 hours after administration (p < 0.01). Mean time to achieve 20% heart rate reduction was 2.1 ± 0.5 hours. Systolic blood pressure between pre and post landiolol administration did not change significantly (72.6 ± 5.9 to 79.7 ± 6.2 mm Hg). Once junctional heart rate was sufficiently suppressed, atrioventricular sequential pacing was introduced to stabilize hemodynamics. Nine of 10 cases (90%) had atrioventricular sequential pacing to maintain appropriate heart rate and restore atrioventricular synchronicity under suppressed junctional heart rate. Subsequently, eight of 10 cases (80%) were converted to regular sinus rhythm within 24 hours after starting landiolol administration. The average time to achieve sinus rhythm conversion was 7.9 ± 3.4 hours. CONCLUSIONS: Landiolol rapidly suppresses junctional heart rate in junctional ectopic tachycardia after pediatric heart surgery without significant blood pressure compromises. Subsequent atrioventricular sequential pacing was effective at restoring atrioventricular synchronicity and stabilizing hemodynamics. Combining junctional rate control with landiolol and atrioventricular sequential pacing is therefore suggested as a promising option for prompt management of postoperative junctional ectopic tachycardia.

A new method for visualizing pulmonary artery microvasculature using synchrotron radiation pulmonary microangiography: the measurement of pulmonary arterial blood flow velocity in the high pulmonary blood flow rat model.

BACKGROUND: Increased pulmonary blood flow (PBF) and shear stress may provoke irreversible vascular remodeling, yet invasive visualization of the microvasculature complicates monitoring. A non-invasive imaging methodology would therefore safely provide mechanistic insights into the progression of high PBF-induced vascular remodeling. PURPOSE: To establish a novel microvasculature visualization method using synchrotron radiation pulmonary microangiography (SRPA) that can also calculate PBF velocity in vivo. MATERIAL AND METHODS: A high PBF rat model was established by making a fistula between the abdominal aorta and inferior vena cava. After eight weeks, SRPA was performed and the dynamic density changes in the right lower pulmonary artery (PA) were calculated by software. SRPA was performed with a HARP (High-Gain Avalanche Rushing amorphous Photoconductor) receiver. PBF velocity was calculated by contrast medium transit time within the PA. All data were presented as mean ± standard error (SE). Student's t-test was used for comparison between the two groups. RESULTS: High dynamic spatial and contrast resolution from SRPA in the PA allowed for clear pulmonary microangiography and accurate detection of higher PBF in the rat model (82.3 ± 8.5 mm/s high-PBF group vs. 46.1 ± 4.3 mm/s control group, P < 0.01). CONCLUSIONS: These novel results demonstrate that SRPA was useful in both visualizing the dynamic flow distribution within the microvasculature and calculating PBF velocity. This newly developed, non-invasive technology may become a powerful tool in clarifying the mechanism of vascular remodeling associated with high PBF-induced shear stress.

Postoperative Dysphagia in Debranching Thoracic Endovascular Aortic Repair with Retroesophageal Carotid-Carotid Bypass.

A carotid-carotid bypass is commonly used in debranching thoracic endovascular aortic repair. When the bypass graft is placed in the retroesophageal position, the esophagus may be compressed by the graft from behind. Therefore, dysphagia may occur postoperatively as a serious complication. To avoid this issue, we recommend placing the bypass graft below the cricoid cartilage.

Renal contrast microangiography with synchrotron radiation: a novel method for visualizing structures within nephrons in vivo.

Background No non-invasive method of observing renal microcirculation in vivo has been established as yet. Although angiography is considered to be ideally suited for the purpose, conventional X-rays cannot be used to image structures smaller than 100 µm. Purpose To develop a method for visualizing the renal arterioles, glomeruli, and proximal tubules of rats in vivo making use of synchrotron radiation. Material and Methods Male Wistar rats were anesthetized, and a catheter was inserted via laparotomy into the abdominal aorta with its tip placed above the renal arteries. The rats were paralyzed with a neuromuscular blocking agent and mechanically ventilated. An inorganic iodine contrast medium was injected via the catheter. The SR derived X-rays transmitted through the subjects were recorded with a CCD camera. Two-dimensional images with a pixel size of 9 µm were obtained. The exposure time was fixed at 50 ms, with a maximum acquisition rate of three images/s. Results Renal arterioles as small as 18 µm in diameter, glomeruli with an average diameter of 173 ± 21 µm, as well as proximal tubules, were clearly visualized. In addition, glomerular density at the peripheral renal cortex was measurable. Conclusion Rat renal microcirculation could be successfully observed in real-time, without exteriorization of the kidney in this study.

Perioperative anticoagulation management during aortic valve replacement complicated by antiphospholipid syndrome.

Patients with antiphospholipid syndrome (APS) are at high-risk for thrombotic and bleeding complications during cardiopulmonary bypass. We report an APS patient who successfully underwent aortic valve replacement while heparin concentrations were monitored using a patient-specific titration curve using viscoelastic coagulation testing.

Intractable Electrical Storm After Coronary Artery Bypass Grafting Originating in Abnormal Purkinje Fibers.

Electrical storm is a rare but critical complication following revascularization in patients with ischemic heart disease. We report the case of a 67-year-old man who developed drug refractory intractable electrical storm after emergent coronary artery bypass grafting for ischemic cardiomyopathy. The electrical storm was successfully eliminated by percutaneous endocardial radiofrequency catheter ablation targeting the abnormal Purkinje-related triggering ventricular premature contractions in a low-voltage zone.

A new technique of in vivo synchrotron radiation coronary microangiography in the rat.

BACKGROUND: Previously, in our laboratory, synchrotron radiation coronary microangiography (SRCA) using Langendorff-perfused rat hearts could visualize a coronary artery of 50 µm in diameter. However, in vivo rat SRCA poses the problem of compromised temporal resolution due to the rapid heart rate of rats. PURPOSE: To establish a simple method of in vivo rat SRCA with bradycardia induced by intravenous injection of adenosine triphosphate disodium hydrate (ATP). MATERIAL AND METHODS: SRCA was performed at the Photon Factory of the High Energy Accelerator Research Organization (Tsukuba, Japan). Eight male Wistar rats were anesthetized. A catheter for injecting the contrast material was inserted into the carotid artery. Temporary bradycardia was induced by an intravenous bolus injection of 5 mg of ATP, and SRCA was performed immediately thereafter. RESULTS: After ATP administration, the average heart rate decreased from 388 to 73 beats per minute. As a result, we could detect a coronary artery as small as 45 µm in diameter. CONCLUSION: Our SRCA system which has a high resolution of 9 µm per pixel could detect a coronary artery as small as 45 µm in diameter in the in vivo rat.

Left Ventricular Perforation during Catheter Ablation in a Patient with Idiopathic Thrombocytopenic Purpura.

Preoperative gamma-globulin therapy was recently performed to prevent bleeding complications in a patient with concomitant idiopathic thrombocytopenic purpura undergoing cardiac surgery. Here we report the case of a 75-year-old male patient with idiopathic thrombocytopenic purpura, chronic aortic dissection, and funnel chest in whom a left ventricular perforation sustained during catheter ablation was repaired during emergent surgery. Despite preoperative gamma-globulin therapy not being performed, bleeding complications were prevented because platelets were preserved by avoidance of cardiopulmonary bypass use. Although the funnel chest made it difficult to secure the operative field, the deep pericardial sutures were effective in repairing the perforation without cardiopulmonary bypass.

Extensive aortic replacement including aortic arch for a mega aorta with chronic aortic dissection via posterolateral thoracotomy.

BACKGROUND: Mega-aortic syndrome including aortic arch and descending aortic aneurysm is a challenging surgical case. Because the aorta continuously dilates, creating the distal anastomosis sites becomes an issue. Despite the developments in endovascular techniques including frozen elephant trunk, in the case of mega-aortic syndrome or mycotic aneurysm, extensive surgical repair is still a strong armamentarium. Our patient had a mega-aorta with chronic aortic dissection. Herein, we show tips regarding concurrent ascending, aortic arch, and descending aortic replacement via posterolateral thoracotomy for this relatively young patient. CASE PRESENTATION: A 46-year-old man with chronic kidney disease had chronic type A aortic dissection with an extensively dilated thoracic aorta from the distal ascending to the descending aorta measuring 63 mm in diameter and abdominal aorta measuring 50 mm. The short segment of the distal descending aorta was narrowed to 36 mm. The patient underwent a concurrent replacement of the distal ascending aorta, aortic arch, and descending aorta via a posterolateral thoracotomy. The patient was extubated on postoperative day (POD) 1 and discharged home without serious complications such as stroke, respiratory failure, or renal failure on POD 18. The 1-year follow-up computed tomography did not find issues in the anastomosis sites; however, the abdominal aorta enlarged from 50 to 58 mm. The patient underwent a thoracoabdominal aortic replacement and recovered well without any complications. CONCLUSIONS: Good exposure and meticulous organ protection methods are key to a safe concurrent replacement of the ascending, aortic arch, and descending aorta via posterolateral thoracotomy.

Structures on the ventricular side of the prosthetic valve in extremely late mitral paravalvular leak: a case report.

Background: Mechanisms of paravalvular leak (PVL) after mitral valve replacement have not been fully delineated. Herein, we report a case of structures on the ventricular side of the mitral valve in a patient with an extremely late PVL. Case summary: A 68-year-old female underwent aortic and mitral valve replacement with a mechanical valve 29 years ago. She was in good health for 28 years. However, exertional dyspnoea appeared 8 months ago. She was admitted to our hospital for congestive heart failure and haemolytic anaemia. Echocardiography showed severe regurgitation due to PVL of the mitral valve. The fluoroscopy showed that a circular calcification was found below the mitral prosthesis. The operation was performed through a median sternotomy. After the aortic cross-clamp, the aortic mechanical valve was removed. The ventricular side of the mitral valve was inspected with the endoscope through the aortic annulus before manoeuvers were performed in the mitral valve. A gap was seen between the prosthetic valve and annular tissue and subvalvular calcification. A bioprosthetic valve was placed with a modified collar-reinforcement technique using a xenopericardium strip. The postoperative course was uneventful. PVL and haemolysis completely disappeared. Discussion: The ventricular side of the prosthetic valve could be observed before the mitral valve was removed. Not only the protruding circular calcification and displacement of the prosthetic valve to the atrial side but also the loss of adhesion and adhesive nature of the annular tissue played a definitive role in the late PVL occurrence and recurrence after percutaneous or surgical repair.

Large-view x-ray imaging for medical applications using the world's only vertically polarized synchrotron radiation beam and a single asymmetric Si crystal.

Objective.X-ray microangiography provides detailed information on the internal structure and function of a biological subject. Its ability to evaluate the microvasculature of small animals is useful for acquiring basic and clinical medical knowledge. The following three conditions are necessary to attain detailed knowledge of biological functions: (1) high temporal resolution with sufficient x-ray intensity, (2) high spatial resolution, and (3) a wide field of view. Because synchrotron radiation microangiography systems provide high sapatial resolution and high temporal resolution as a result of their high x-ray intensity, such systems have been developed at various synchrotron radiation facilities, starting with the photon factory, leading to numerous medical discoveries. However, the three aforementioned functions are incompatible with the use of synchrotron radiation because the x-ray intensity decreases when a wide field of view is obtained. To overcome these problems, we developed a new x-ray optical system for microangiography in rats using synchrotron radiation x-rays.Approach.Instead of using monochromatic synchrotron radiation x-rays with a conventional double-crystal monochromator, we used white synchrotron radiation x-rays and an asymmetric Si crystal to simultaneously monochromatize the beam and widen the field of view.Main results.The intensity profile and spatial resolution of the x-ray images were then evaluated. The proposed x-ray optics increased the x-ray intensity and beam width by factors of 1.3 and 2.7, respectively, compared with those of conventional monochromatic x-rays. In addition,in vivostudies on microangiography in rats were performed to confirm that the images had sufficient intensity, spatial resolution, and field of view. One of a series of images taken at 50 ms frame-1was shown as an example.Significance.This x-ray optics provides sufficient x-ray intensity, high spatial resolution, and a wide field of view. This technique is expected providing new insights into the evaluation of the vascular system.

Surgical removal of infected pacemaker leads without cardiopulmonary bypass after failed extraction using the Excimer Laser Sheath Extraction System.

With the growing number of cardiac pacemakers and internal cardioverter defibrillator implantations, problems with endocardial lead infection have been increasing. The newly developed Excimer Laser Sheath Lead Extraction System has been recognized as being highly useful for removing chronic infected leads. However, serious bleeding complications are a concern when this system is used. Here we report our experience with a 67-year-old man who was diagnosed with pacemaker endocarditis. Initially, lead removal was attempted using the Excimer Laser Sheath Extraction System, though this was abandoned because of severe adhesion of the leads and the junction of the supra vena cava (SVC) with the right atrium. Surgical removal of the leads was performed without using cardiopulmonary bypass and the leads were removed without any complications. During surgery, we found there was a silent perforation of the innominate vein brought about by the Excimer Laser Sheath System. Also, the junction of the SVC with the right atrium was thought to be an area potentially at high risk of perforation, because of a lack of surrounding tissue. It is our opinion that those who carry out procedures with the Excimer Laser Sheath System should understand the potential risk of perforation based on cardiac anatomy and should be prepared for lethal bleeding complications. Also, for emergent situations, we believe that close backup by a cardiovascular surgical team should be considered essential for performing the Excimer Laser Sheath Lead Extraction safely.