No abstract

Mediastinitis occurs after cardiac surgery and is a major threat to patient’s life due to postoperative bleeding and deep sternal wound infection. Major challenge in treating this condition is that it demands a material that should adhere to the applied site and act as both a hemostatic and an antibacterial agent. On the basis of this we have developed an in situ forming tissue adhesive chitin–fibrin (CH-FB) gel with tigecycline loaded gelatin nanoparticles (tGNPs) for controlling bleeding and preventing bacterial infection. Spherical shaped tGNPs (231 ± 20 nm) were prepared and characterized. In situ forming tGNPsCH-FB gel was formed using a dual syringe applicator in which one syringe was loaded with a mixer of fibrinogen solution, chitin gel, and tGNPs; the other syringe was loaded with a mixture of thrombin solution, chitin gel, and tGNPs. Both these mixtures were injected together. In situ gel formed within a minute and exhibited excellent tissue adhesive property. tGNPsCH-FB gel was found to be cyto-compatible against human umbilical vein endothelial cells (HUVECs). Sustained release of tigecycline from tGNPsCH-FB gel was found to occur over 21 days. In vitro antibacterial activity of tGNPsCH-FB gel was tested against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli (E. coli), and their clinical isolates. Furthermore, in vivo hemostatic potential of tGNPsCH-FB gel was evaluated in deep organ injuries created in Sprague–Dawley rats. The developed gel exhibited rapid blood clotting potential by achieving hemostasis within 154 and 84 s under femoral artery (pressured) and liver (oozing) bleeding conditions. Hence, these findings exhibit the potential application of the developed tGNPsCH-FB gel to adhere at surgical site for controlling bleeding and prevent bacterial infection after cardiac surgery.

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease with many genotype and phenotype variations. Earlier terminologies, hypertrophic obstructive cardiomyopathy and idiopathic hypertrophic sub-aortic stenosis are no longer used to describe this entity. Patients present with or without left ventricular outflow tract (LVOT) obstruction. Resting or provocative LVOT obstruction occurs in 70% of patients and is the most common cause of heart failure. The pathology and pathophysiology of HCM includes hypertrophy of the left ventricle with or without right ventricular hypertrophy, systolic anterior motion of mitral valve, dynamic and mechanical LVOT obstruction, mitral regurgitation, diastolic dysfunction, myocardial ischemia, and fibrosis. Thorough understanding of pathology and pathophysiology is important for anesthetic and surgical management.

Uncontrolled bleeding can lead to many complications that might cause multiple organ failures and even death. Of all the hemostatic agents used, chitosan has been reported to show better hemostatic potential. It acts through one mechanism involved in hemostasis that is plug formation by adhering to the injured site. Hence our focus is to enhance the hemostatic potential of chitosan (Ch) hydrogel by incorporating nano whitlockite (nWH: Ca18Mg2(HPO4)2(PO4)12) that would release Ca2+, Mg2+, and PO4 3– ions that would simultaneously initiate the coagulation cascade. Ch-nWH composite hydrogel can act simultaneously on different mechanisms involved in hemostasis and bring about rapid bleeding control. The nWH particles were synthesized using precipitation technique and were characterized. Particle size of nWH was found to be 75 ± 5 nm. Composite hydrogel was characterized using FTIR and XRD to confirm the presence of different constituents of the hydrogel. Rheological studies showed the shear-thinning property and increased elastic modulus of the composite hydrogel compared to Ch hydrogel. 2%Ch-4%nWH hydrogel was observed to be cytocompatible with Human Umbilical Vein Endothelial Cells (HUVEC). In the in vitro blood clotting analysis using citrated human whole blood, 2%Ch-4%nWH hydrogel showed rapid blood clot formation compared to control 2%Ch hydrogel. Further in vivo experiments performed on liver and femoral artery injuries created on Sprague–Dawley (S.D) rat model reveals that 2%Ch-4%nWH hydrogel promoted rapid bleeding control and less volume of blood loss compared to Ch hydrogel. These in vitro and in vivo results showed that incorporation of nWH has enhanced the hemostatic potential of Ch hydrogel. Therefore, the synthesized 2%Ch-4%nWH hydrogel may be a promising system that could bring about rapid hemostasis during life threatening bleeding.

Ischemic mitral regurgitation (IMR) is a frequent complication of left ventricular (LV) global or regional pathological remodeling due to chronic coronary artery disease. It is not a valve disease but represents the valvular consequences of increased tethering forces and reduced closing forces. IMR is defined as mitral regurgitation caused by chronic changes of LV structure and function due to ischemic heart disease and it worsens the prognosis. In this review, we discuss on etiology, pathophysiology, and mechanisms of IMR, its classification, evaluation, and therapeutic corrective methods of IMR.