Incidental Discovery of Anomalous Left Coronary Artery Arising from the Pulmonary Artery in a Coronavirus Disease-2019 Patient: A Blessing in Disguise

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a serious congenital malformation. Reports about asymptomatic, incidentally discovered ALCAPA in adults are scarce. We describe a patient with no known pre-existing cardiac condition admitted to our hospital with coronavirus disease 2019 (COVID-19) and was incidentally found to have ALCAPA. To the best of our knowledge, this is the first reported case of incidentally discovered ALCAPA in a COVID-19 patient and highlights the importance of appropriate investigation of the coronary status by Multidetector Cardiac Computed Tomographic Angiography (MDCCTA) in individuals with asymptomatic left ventricular dysfunction. The presentation of this case, discussion and literature review serves to iterate the necessity of appropriately investigating patients with asymptomatic LV dysfunction.     

Transjugular intrahepatic portosystemic shunt in cirrhosis: An exhaustive critical update

More than five decades after it was originally conceptualized as rescue therapy for patients with intractable variceal bleeding, the transjugular intrahepatic portosystemic shunt(TIPS) procedure continues to remain a focus of intense clinical and biomedical research. By the impressive reduction in portal pressure achieved by this intervention, coupled with its minimally invasive nature, TIPS has gained increasing acceptance in the treatment of complications of portal hypertension. The early years of TIPS were plagued by poor long-term patency of the stents and increased incidence of hepatic encephalopathy. Moreover, the diversion of portal flow after placement of TIPS often resulted in derangement of hepatic functions, which was occasionally severe. While the incidence of shunt dysfunction has markedly reduced with the advent of covered stents, hepatic encephalopathy and instances of early liver failure continue to remain a significant issue after TIPS. It has emerged over the years that careful selection of patients and diligent post-procedural care is of paramount importance to optimize the outcome after TIPS. The past twenty years have seen multiple studies redefining the role of TIPS in the management of variceal bleeding and refractory ascites while exploring its application in other complications of cirrhosis like hepatic hydrothorax, portal hypertensive gastropathy, ectopic varices, hepatorenal and hepatopulmonary syndromes, non-tumoral portal vein thrombosis and chylous ascites. It has also been utilized to good effect before extrahepatic abdominal surgery to reduce perioperative morbidity and mortality. The current article aims to review the updated literature on the status of TIPS in the management of patients with liver cirrhosis.     

Porcine bioprosthetic heart valves: The next generation

There have been significant advances in organ xenotransplantation (cross-species transplantation), especially in the development of genetically engineered pigs, but clinical trials of solid organ transplants are still a time away. However, there is a form of pig-to-human xenotransplantation that has been taking place since the 1960s-bioprosthetic heart valve (BHV) replacement. Recently, there has been increasing evidence that, despite glutaraldehyde fixation of BHVs, there is a significant immune reaction to the valves, leading to calcification, rapid structural deterioration, and failure, particularly in young patients who have a more vigorous immune system and metabolism than the elderly. However, it is the young patients who would most benefit from such BHVs because these avoid the complications associated with the lifelong anticoagulation required with mechanical valves. In this review, we examine pathologic and immunohistochemical reports of failed BHVs that suggest that there is an immune response to these valves. Small animal studies that link the development of calcification and BHV failure to the immune response are reviewed. We draw parallels between the problems of glutaraldehyde-fixed tissue xenotransplantation and those currently being faced in live organ xenotransplantation. Finally, we discuss the advances being made in the production of genetically modified pigs and the evidence that these pigs may become a source of BHVs that can be used worldwide to treat valvular heart disease in children and young adults (for whom there is no ideal valve replacement in existence today). The design of a BHV that is resistant to the host's immune response would be a major step forward in cardiac surgery.     

In vitro evaluation of novel low-pressure spark plasma sintered HA–BG composite scaffolds for bone tissue engineering

The low-pressure spark plasma sintering (SPS) technique is adopted to fabricate hydroxyapatite–bioglass (HA–BG) scaffolds while maintaining the physical properties of both components, including their bulk and relative density and hardness. However, prior to their orthopaedic and dental applications, these scaffolds must be validated via pre-clinical assessments. In the present study, scaffolds with different ratios of HA : BG, namely, 100 : 0 (HB 0 S), 90 : 10 (HB 10 S), 80 : 20 (HB 20 S) and 70 : 30 (HB 30 S) were fabricated. These scaffolds were characterized by investigating their physicochemical properties (X-ray diffraction (XRD) and surface wettability), bioactivity in a simulated body fluid (SBF) (field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR) and calcium dissolution), antimicrobial properties, biocompatibility and osteoinduction of human bone marrow-derived mesenchymal stromal cells (hBMSCs) and human monocyte immune cell response. The XRD and surface wettability results confirmed no formation of undesirable phases and the enhanced surface hydrophilicity of the scaffolds, respectively. The bioactivity in SBF indicated the formation of bone-like apatite on the surface of the scaffolds, corresponding to an increase in BG%, which was confirmed through FTIR spectra and the increasing trend of calcium release in SBF. The scaffolds showed inhibition properties against Staphylococcus aureus and Staphylococcus epidermidis. The scanning electron microscopy (SEM) micrographs and Alamar Blue proliferation assay indicated the good attachment and significant proliferation, respectively, of hBMSCs on the scaffolds. Alizarin Red S staining confirmed that the scaffolds supported the mineralisation of hBMSCs. The osteogenic protein secretion (bone morphogenetic protein-2 (BMP2), type-I collagen (COL1) and osterix (OSX)) was significant on the HB 30 S-seeded hBMSCs when compared with that of HB 0 S. The monocyte migration was significantly halted in response to HA–BG-conditioned media when compared with the positive control (monocyte chemoattractant protein-1: MCP-1). In conclusion, the HB 30 S composite scaffold has a greater potential to substitute bone grafts in orthopaedic and dental applications.

HB 30 S composite scaffold inhibits Staphylococcus spp., supports the biocompatibility and osteogenic differentiation of hBMSCs and resists monocyte migration.