Bioprosthetic Valve Deterioration: Accumulation of Circulating Proteins and Macrophages in the Valve Interstitium.

Histologic evaluations revealed excessive accumulations of macrophages and absence of fibroblastic interstitial cells in explanted bioprosthetic valves. Comprehensive gene and protein expression analysis and histology unveiled an accumulation of fibrinogen and plasminogen, an activator of infiltrated macrophages, from degenerated valve surfaces in the interstitial spaces. These pathologies were completely reproduced in a goat model replaced with an autologous pericardium-derived aortic valve. Further preclinical animal experiments using goats demonstrated that preventing infiltration of macrophages and circulating proteins by increasing collagen density and leaflet strength is an effective treatment option.

Hypoxic Culture Maintains Cell Growth of the Primary Human Valve Interstitial Cells with Stemness.

The characterization of aortic valve interstitial cells (VICs) cultured under optimal conditions is essential for understanding the molecular mechanisms underlying aortic valve stenosis. Here, we propose 2% hypoxia as an optimum VIC culture condition. Leaflets harvested from patients with aortic valve regurgitation were digested using collagenase and VICs were cultured under the 2% hypoxic condition. A significant increase in VIC growth was observed in 2% hypoxia (hypo-VICs), compared to normoxia (normo-VICs). RNA-sequencing revealed that downregulation of oxidative stress-marker genes (such as superoxide dismutase) and upregulation of cell cycle accelerators (such as cyclins) occurred in hypo-VICs. Accumulation of reactive oxygen species was observed in normo-VICs, indicating that low oxygen tension can avoid oxidative stress with cell-cycle arrest. Further mRNA quantifications revealed significant upregulation of several mesenchymal and hematopoietic progenitor markers, including CD34, in hypo-VICs. The stemness of hypo-VICs was confirmed using osteoblast differentiation assays, indicating that hypoxic culture is beneficial for maintaining growth and stemness, as well as for avoiding senescence via oxidative stress. The availability of hypoxic culture was also demonstrated in the molecular screening using proteomics. Therefore, hypoxic culture can be helpful for the identification of therapeutic targets and the evaluation of VIC molecular functions in vitro.

Unique Angiogenesis From Cardiac Arterioles During Pericardial Adhesion Formation.

OBJECTIVES: The molecular mechanisms underlying post-operative pericardial adhesions remain poorly understood. We aimed to unveil the temporal molecular and cellular mechanisms underlying tissue dynamics during adhesion formation, including inflammation, angiogenesis, and fibrosis. METHODS AND RESULTS: We visualized cell-based tissue dynamics during pericardial adhesion using histological evaluations. To determine the molecular mechanism, RNA-seq was performed. Chemical inhibitors were administered to confirm the molecular mechanism underlying adhesion formation. A high degree of adhesion formation was observed during the stages in which collagen production was promoted. Histological analyses showed that arterioles excessively sprouted from pericardial tissues after the accumulation of neutrophils on the heart surface in mice as well as humans. The combination of RNA-seq and histological analyses revealed that hyperproliferative endothelial and smooth muscle cells with dedifferentiation appeared in cytokine-exposed sprouting vessels and adhesion tissue but not in quiescent vessels in the heart. SMAD2/3 and ERK activation was observed in sprouting vessels. The simultaneous abrogation of PI3K/ERK or TGF-ß/MMP9 signaling significantly decreased angiogenic sprouting, followed by inhibition of adhesion formation. Depleting MMP9-positive neutrophils shortened mice survival and decreased angiogenic sprouting and fibrosis in the adhesion. Our data suggest that TGF-ß/matrix metalloproteinase-dependent tissue remodeling and PI3K/ERK signaling activation might contribute to unique angiogenesis with dedifferentiation of vascular smooth muscle cells from the contractile to the synthetic phenotype for fibrosis in the pericardial cavity. CONCLUSIONS: Our findings provide new insights in developing prevention strategies for pericardial adhesions by targeting the recruitment of vascular cells from heart tissues.

Usefulness of contrast computed tomography for diagnosing left ventricular thrombus before impella insertion.

The Impella (Abiomed, Danvers, MA, USA) is a novel percutaneous heart pump device for left ventricular (LV) assistance; however, LV thrombus is a notable contraindication for this device. Contrast computed tomography assessment is useful for detecting LV thrombus and preventing thromboembolism in patients recommended for Impella use. .

A case report of thrombotic complete obstruction of the ascending aorta as a complication of Venoarterial extracorporeal membrane oxygenation support: steps to prevent thrombosis.

BACKGROUND: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is an essential device in the field of emergency and intensive-care medicine. However, long-term use of VA-ECMO has various severe complications, including thrombosis. CASE PRESENTATION: A 60-year-old man underwent his third aortic root replacement using a homograft because of infectious endocarditis. Although the operation was difficult because of severe adhesion caused by the two previous interventions, aortic root replacement using a homograft was performed. At the time of withdrawal from cardiopulmonary bypass, the maintenance of hemodynamics was difficult because of bleeding from the surgical site, leading to hypovolemic shock. Cardiac function subsequently deteriorated; therefore, VA-ECMO was established and the operation was finished. Three days later, thrombus was formed inside the homograft and completely occluded ascending aorta. Evacuation of hematoma was performed, however, cardiac function was not ameliorated. Eventually, the patient had brain infarction and died. To prevent thrombus formation in very severe low cardiac output cases under VA-ECMO management after surgery, to prevent the stagnation of the blood flow from VA-ECMO will be necessary because anticoagulant therapy will be difficult. Impella ventricular assist device which is recently used widely generates anterograde blood flow and effectively prevents stagnation. CONCLUSIONS: To prevent thrombus formation in cases of very severe low cardiac output, Impella® should be combinatorially introduced from the beginning of VA-ECMO establishment to prevent thrombosis.

[Minimally Invasive Cardiac Surgery Following Anesthesia Induction under Percutaneous Cardiopulmonary Support for Prosthetic Valve Dysfunction and Severe Pulmonary Hypertension in a Patient with Previous Mitral Valve Replacement].

A 47-year-old woman with a history of mitral valve replacement (MVR) through a median sternotomy was admitted to our hospital due to dyspnea on exertion. Echocardiography showed bioprosthetic valve dysfunction with mitral stenosis. Right heart catheter examination revealed severe pulmonary hypertension and right ventricular dysfunction. We considered that she could not tolerate the hemodynamic changes during induction of general anesthesia without any cardiopulmonary support. Therefore, the percutaneous cardiopulmonary support was started before induction of anesthesia. To avoid the risk of injury to cardiac structures, we performed redo mitral valve replacement via right mini-horacotomy in the 4th intercostal space. Severe calcification was found in the leaflets of the prosthetic valve. She was discharged home on postoperative day 42.

Refractory ventricular fibrillations after surgical repair of atrial septal defects in a patient with CACNA1C gene mutation - case report.

BACKGROUND: Congenital long QT syndrome (LQTS) can cause ventricular arrhythmic events with syncope and sudden death resulting from malignant torsades de pointes (TdP) followed by ventricular fibrillations (VFs). However, the syndrome is often overlooked prior to the development of arrhythmic events in patients with congenital heart diseases demonstrating right bundle branch block on electrocardiogram (ECG). We present a case of an adult patient with congenital heart disease who developed VFs postoperatively, potentially due to his mutation in a LQTS related gene, which was not identified on preoperative assessment due to incomplete evaluation of his family history. CASE PRESENTATION: A 64-year-old man was diagnosed as having multiple atrial septal defects. He presented with no symptoms of heart failure. His preoperative ECG showed complete right bundle branch block (CRBBB) with a corrected QT interval time of 478 ms. He underwent open-heart surgery to close the defects through median sternotomy access. Three hours after the operation, he developed multiple events of TdP and VFs in the intensive care unit. Cardiopulmonary resuscitation and multiple cardioversions were attempted for his repetitive TdP and VFs. He eventually reverted to sinus rhythm, and intravenous beta-blocker was administered to maintain the sinus rhythm. After this event, his family history was reviewed, and it was confirmed that his daughter and grandson had a medical history of arrhythmia. A genetic test confirmed that he had a missense mutation in CACNA1C, p.K1580 T, which is the cause for type 8. CONCLUSIONS: This case highlights the importance of paying attention to other ECG findings in patients with CRBBB, which can mask prolonged QT intervals.

Aortopulmonary collateral arteries: a rare complication after arterial switch operation for transposition of the great arteries.

Collateral vascular arteries from the descending aorta to the pulmonary arteries are uncommon after arterial switch operation. Here, we report the case of a baby girl treated with coil embolization for abnormal blood flow from the descending aorta to the pulmonary arteries after arterial switch operation. A baby girl weighing 1324 g was delivered at 32 weeks 4 days of gestation, and she had D-transposition of the great arteries and a ventricular septal defect. She underwent nitrogen inhalation to reduce pulmonary blood flow before arterial switch operation. After the operation, she presented with left heart failure due to the presence of abnormal blood flow from the descending aorta to the pulmonary arteries, and she was successfully treated with coil embolization. After the treatment, her condition improved dramatically, and she was discharged without any complications.