Cole Latvis - Immersion Week 4 - Open Heart Surgery and Data Analysis

This week I watched two open chest/heart surgeries and began analyzing data for my research project.

On Monday a fellow in cardiothoracic surgery that I have been in contact with helped me get into the operating room. The first procedure I observed was an ascending aorta replacement. I had requested to watch this surgery particularly because it is related to both my summer project and my PhD project. My summer project is to use MRI imaging to study how Dacron graft placement in the ascending aorta effects distal aortic wall remodeling, which potentially leads to further complications. My main PhD project is to build better vascular grafts, so it was very insightful to watched exactly how current synthetic grafts are handled and about the perspectives of the surgeons using the technology. I was even able to briefly handle explanted aortic tissue and was surprised by the toughness of the vessel. The synthetic graft used was also fascinating. I had seen Dacron grafts before, but this one had a built-in bioprosthetic aortic valve. The idea of fusing these two Technlogies was not really surprising, but I was unaware that the technologies had been developed to the point that efficient constructions such as this were available on the market. In addition to the aorta replacement, I also observed a coronary artery bypass using an internal mammary artery graft. This was also interesting to watch as this is an application where no current synthetic grafts are viable.

Tuesday was a slow day for me with the exception of goodbyes to the senior fellows who were graduating. I finally got access to the dataset I need for my research, but no computers were available. However, this problem would alleviate itself since senior fellow were graduating. To keep myself busy I read some aortic graft literature. I began with some papers by Dr. Weinsaft’s group, but eventually found my way to papers on bioresorbable grafts like the ones I am working on for my main PhD project.

Wednesday was another cardiothoracic surgery day. This time I watched an operation where three things were done. First, the mitral valve was replaced with a bioprosthetic one, which required the left atrium to be opened. It was interested to see how the valve appeared to have some Dacron-like material as a skirt for a suture to be run through. This made me realize that the biomaterials I create in lab could have applications beyond simply full vascular conduits. The second procedure was a left atrial appendage ligation. This was a simple procedure where the left atrial appendage as sutured shut to prevent blood clots from escaping the pouch. The last procedure was a MAZE, where a probe is used to cryoablate the neck of the pulmonary veins, which as a source of atrial fibrillations. I had seen a similar procedure done previously in the electrophysiology lab where a catheter was used to ablate the neck of the pulmonary veins.

For the rest of the week, I was able to really get going on my summer research project. Briefly, my project is to look at how ascending aorta grafts effect the distal aortic wall strain. The goal is to show that the stiff Dacron grafts increase energy propagation to more distal portions of the aorta, leading to greater strains. It is hypothesized that this increased strain is related to abnormal aortic wall remodeling that can lead to further complications such as aneurysm and dissection post graft placement. Previous work has been done to show the relationship between Dacron grafts and increased strain, but the analysis was done using custom MATLAB code. My project so far is looking to see if I can replicate the analysis using a commercially available software made for ventricular strains. So far, the results look promising, though more optimization in needed to make the software work well for my purposes.

Overall, this was an impactful week. I gain a lot of valuable experiences and finally feel like I was actually working on a real project.