Sample Medicine Essay Paper on Ventricular septal defects (VSDs)

Summary 9

The Perspective

Ventricular septal defects (VSDs) are grouped among the congenital heart defects that affect children and a leading cause of death in infants below the age of one year. Currently, the procedure for correcting this defect is by using a knitted polyester patch, bovine pericardium, or polytetra fluorethylene (PTFE). These methods have turned out ineffective when used for long-term purposes. It is because the material used for patching is large hence does not match the heart size making it impossible to accurately close VSDs. Bacterial nanocellulose (BNC) is the anticipated hope for finally solving this defect in children. It is because this biomaterial has promising properties that is anticipated to bring good results. Some of the properties that makes BNC effective are its mechanical strength, ability to contain 99% water and its favorably elastic nature, which would make patching easy ensuring that VSDs has been properly closed (Lang et al. 1014).

The Proposed Technique and Application

The first method was fabricating BNC into patches using Gluconacetobacter xylinus bacteria. The patches were cut in the shape of a rectangle with their measurements being 5cm by 3cm after which they were placed into two different groups. Tensile tests were used to conduct the experiment through the help of tensile testing machine after which it was applied at a preload of 0.5 N. H. However, rather than using the test on humans, the first experiment was conducted on animals, which, in this case, involved German landrace pigs. However, care and ethical standards were met during the experiment which was approved by the local Governmental Commission. Anesthesia together with surgical preparation was conducted just like the case with humans (Lang et al. 1015). The operation was conducted without cardiopulmonary bypass. Echocardiography and hemodynamic measurements were used during the operation to monitor the pig’s heart rate, central venous pressure, and arterial pressure. Any potential valve insufficiencies and residual shunts were also monitored using a two-dimensional echocardiography.

Muscular VSDs had to be created when the surgical process was being conducted. The process enabled the BNC patch to perform its work perfectly by closing the VSDs properly. However, during the process, the pig was alive and its heart was beating at a vivo model. The aim for doing this was to ensure that the strengths of the BNC patches and modulus were established before exposing the pig to the operation and after the procedure was completed. The pig was then monitored for 90 days with the first inspection on the progress of BNC patch to completed close VSDs. However, it is possible to monitor the pig or a person who has gone through the operation after 7 days or 30 days. During the process, immunohistochemistry, macropathology, and histology were some of the experiments that were performed.


During the investigation period when mechanical testing was being conducted, the tensile strength and Young’s module of the BNC patch had significantly decreased. It was attributed by the contact it had with blood from 6.3 ± 1.9 to 3.86 ± 2.2 MPa (P < 0.01) and 0.33 ± 0.06 to 0.26 ± 0.06 MPa (P < 0.01), which was an indication that the elasticity level of the patch had increased (Lang et al. 1015).  However, like any other normal operation, inflammatory reactions were experienced and cellular organization progressed with time. Nonetheless, it is important to identify the BNC’s long term impacts which call for the health care practitioners to conduct further study on the subject. It will enable them to identify if the tissues has the potential to react with the patch overtime or if there were any concepts involving elasticity that may make the VSDs patch ineffective. There is also a need to identify a biodegradable type of BNC, which is assumed to be more efficient than the patch materials.                                                                                                                                                                                                                                                                                                

Work Cited

Lang, Nora, et al. “Bacterial nanocellulose as a new patch material for closure of ventricular septal defects in a pig model.” European Journal of Cardio-Thoracic Surgery, vol.47. no. 1, 2015, p. 1013-1021.