Week 7: So Long NYC

 Guy Scuderi

Well, just like that, my immersion experience is complete. These past seven weeks have surely flown bye. I cannot believe it is already over. This experience as a whole is going to be something I look back on for a long time. I am beyond happy with how my experience went as I explored all around the city and learned more than I could have ever imagined in the clinical setting. All my expectations of how this immersion term was going to be were met and I am highly satisfied with the outcome of this experience.

This past week basically involved me finishing up my clinical research project. After extracting all the data from the 22 included articles, I went forward and computed some basic calculations on the overall reoperation characteristics of the entire meta-analysis cohort, as shown in Table 1 below.

This initial data was pretty interesting. If you recall, the main research question Dr. Gaudino and Dr. Weinsaft wanted to look at through this meta-analysis was whether or not genetic-mediated aneurysms (Marfan syndrome or BAV) lead to a higher reoperation rate than those who do not have a genetic predisposition. From the 6,091 patients who underwent a previous aortic aneurysm repair, a total of 655 patients had to undergo at least one reoperation. About one out of every ten patients who has an aneurysm repair at some point  develops another aneurysm and must be reoperated on.

Also surprisingly, out of the 487 Marfan syndrome patients, 173 patients had to undergo at least one reoperation, which is about one out of every three individuals. If you recall from my previous blog posts, Marfan syndrome is a genetic connective tissue disorder that is associated with a mutation in the gene encoding the protein fibrillin-1 (FBN1). With this mutations, patients with Marfan syndrome have abnormal connective tissue and have a greater chance at developing aortic aneurysms. These patients need to be closely monitored at a much higher frequency and greater caution than those that do not have any genetic-mediated aneurysms.

Another parameter that we were interested in looking at was the number of patients who have genetic abnormality of bicuspid aortic valves and received reoperations. Patients who have bicuspid aortic valves (these valves are supposed to be tricuspid) have abnormal hemodynamic flow (blood flow) in their aorta and therefore are thought to have a higher likelihood of developing aortic aneurysms. However, there were very limited amounts of data available in the 22 articles for this information, with only three papers including any information on the number of BAV patients who received an initial aortic aneurysm repair and the number of BAV patients who received reoperations. One paper had 305 BAV patients with only 3 BAV patients receiving reoperations. Therefore, overall, this data is pretty inconclusive.

Besides reoperation rates, I also analyzed overall reoperation mortality rates, which was
11% (58/539) patients. This indicates that patients who require reoperations are a high risk group of individuals. These types or reoperations are very challenging for the surgeon and much more likely to have surgical associated complications.

After looking through this initial reoperation data, I also brokedown this data further into the various types of initial procedures and reoperations that were performed on this meta-analysis cohort of patients, as shown in Figure 1 below. As shown in the figure, the majority of the initial aortic aneurysm operations were on the ascending aorta or proximal arch while the majority of the reoperations were on distal regions of the aorta (mostly the descending aorta, distal arch, or thorocoabdominal aorta). This further supports the main motivation for this meta-analysis that proximal operations on aortic aneurysms will lead to a higher likelihood of developing distal aneurysms that must be reoperated on in the near future.

Figure 3: Types of initial aortic procedures and reoperations performed. A) Initial aortic aneurysm repairs with percentages for each type of aortic region operated on out of the entire cohort. A total of 5,573 initial procedures were performed, which excludes any miscellaneous operations. B) Aortic aneurysm reoperations with percentages of each type of aortic region operated on. A total of 638 reoperations were performed, which excludes miscellaneous and TEVAR (thoracic endovascular aortic repair) procedures.; TAAA = thoracoabdominal aortic aneurysm. Elephant trunk procedures involve grafting the ascending, arch, portion of the descending, as well as the branching arch arteries. AVR = aortic valve replacement.

Unfortunately, due to time, I was unable to meet with Dr. Gaudino's research team statistician to run any statistical analyses on this extracted data. However, they told me they would keep me updated on the analysis when I am gone and that due to the amount of work I put into this clinical research project over the summer that I will most likely be receiving a middle authorship on this paper when they go forward and publish it within the next couple months, which I am really happy about. 

Overall, I was glad I was able to dive deep into some clinical research while being here in NYC and learning about the ins and outs of the cardiovascular unit of the hospital. Surgeons rely heavily on the information they gain from these types of retrospective clinical studies since many of them are often fast with complicated and challenging cases that require a thorough risk benefit analyses on the best surgical procedure to perform in order to mitigate the amount of morbidity and mortality. 

Well, that's about it. I hope you enjoyed reading my weekly blogs over these past seven weeks! So long NYC, I am sure this will not be the last time we cross paths.