Week 3

I finally dived into my project and, between surgeries, spent some time at the library to get familiar with all the medical jargon the OR bombarded me these past two weeks. Dr. Salemi is doing a clinical study on patients that have undergone a transcatheter aortic valve implantation (TAVI) and has asked me to help him with the analysis of patient and operative data. TAVI is suggested to patients diagnosed with severe aortic stenosis and that are deemed too high-risk for an open heart surgery. TAVI is considered as a minimally invasive procedure because it does not involve sternotomy. Instead, a mesh-like artificial valve (similar to a stent) is mounted on a catheter and guided to the damaged valve through different access routes: transfemoral, transapical, or transaortic. I personally assisted to a couple of transfermoral TAVIs last week in the cat-lab.

In the medical field, some believe this kind of procedure will one day replace open heart surgeries, though this remains very debatable among surgeons. Dr. Guy, for instance, believes robots will one day take over the OR. He thinks robots will be capable to provide an augmented level of feedback and degree of freedom to the surgeon. While rounding in the morning, I also heard many patients insisting in having TAVI over the open heart alternative. Not everyone is eligible however. For example, patient with recent myocardial infarction, congenital heart defects, ventricular dysfunction, or untreated coronary disease are excluded from TAVI.

Dr. Salemi is interested in comparing the pre-, peri-operative and long-term clinical outcome characteristics after TAVI between three groups patients: those who manifest left atrial thrombus (LAT), spontaneous echo contrast (SEC) or neither. LAT are blood clots in the left atrium appendage which are associated with atrial fibrillation (AF) and embolic events (strokes). SEC is a phenomena observed on a echocardiogram and is characterized by a “smoke-like" swirling pattern of blood flow in the left atrium created by aggregation of blood cells. Like LAT, the presence of SEC has been associated with a higher risk of AF and embolism. Dr. Salemi has given me a huge dataset with characteristics from 369 patients such as age, sex, echocardiogram measurements such as ejection fraction (EF), mean blood gradient and jet velocity, valve type and dimensions, as well as preoperative and post-operative characteristics. He asked me to evaluate which of these characteristics is significant for each group. This statistics-oriented project will be a good opportunity for me to further appreciate what I experience in the OR.