Week 5 – TEEs and Cardiac Catheterization

Week five of summer immersion I shadowed Dr. Healy in TEE, she got me in to see cardiac catheterization, I continued the embryonic stem (ES) cell culture experiments, and on the recommendation of Dr. Frayer I met with Dr. Chen in pediatric cardiology. In TEE on Tuesday there was a patient on the critical care floor who had confirmed dissection of the descending aorta and the TEE was used to check for dissection of the ascending aorta. I met some of the critical care nurses and asked them how their floor was organized. Nurses are apparently assigned to particular home units. I was asked if I was from Europe (where the organization of the nursing floor might be different).
After there was a gap between TEE patients, Dr. Healy escorted me to Cardiac Catheterization Lab where Dr. Bergman was working. Cardiac Cath is separated into two rooms. One room has the patient on the table surrounded by x ray machines. Doctors and nurses and technicians (who are all wearing lead protective gear) are setting up in the room and prepping the patient for the procedure. The other room has computers and monitors and windows that look into the procedure room (this is where I got to sit). In the viewing room I met a researcher who was also there to watch the procedure, and to see if the patient qualified for a clinical study for a Medtronic drug eluting stent. The patient is evaluated using a set of inclusion and exclusion criteria and depending on the findings of the procedure may or may not qualify for the study. First Dr. Bergman guided a catheter into the femoral artery using a wire, the catheter is then navigated into the coronary arteries of the heart. Contrast dye, or fluoroscopy dye that interacts with the x-rays is injected to show the branches of the arteries. When the dye is injected into the blood vessels the screen shows a web of blood vessels around the heart and it is possible to see areas of narrowing or constriction or where downstream flow is restricted. It is also possible to see areas of calcification. The x-rays will give a 2D picture of a 3D structure, so pictures of the same artery from several angles are taken to reconstruct the volume of the blood vessel. The patient had two seriously occluded arteries, the distal circumflex and the obtuse marginal, and the plan was to fix the more significant one with a stent. Note: The diagnosis of the narrowing of the arteries, calling the patient’s primary cardiologist or physician to discuss the results, and deciding to deploy a stent is all done at that time since the catheter is already in place in the patient’s coronary arteries. A wire and balloon is deployed through the catheter to pre-dilate the lesion where the stent will be put. Then a crimped stent and balloon is put in. The balloon is inflated to expand the stent, and then the catheter and balloon is removed, leaving behind the stent in the lesion.
On Thursday, Fai and I went to TEE in the morning and then went to see Cardiac Cath. The patient in cardiac cath was scheduled for a colectomy, but had had an abnormal stress test in nuclear cardiology and needed to have his heart checked out before he could undergo a major abdominal surgery. The patient had an unusual skin problem in the groin area. So, instead of putting the catheter into the femoral artery, the doctors used a brachial approach (traveling up an artery in the arm). While the doctors are searching for areas of narrowing and blockage, they are also looking to see if the heart has formed collaterals, or natural bypasses of blood to areas that have lost their normal blood supply. Unfortunately, this patient had a LAD (Left Anterior Descending) coronary artery with a lesion that was almost 90% blocked in addition to other occluded areas. The doctors felt that even with stents and a month of anti-thrombogenic drugs there might still be incomplete vascularization, and recommended complete bypass surgery before the patient could have abdominal surgery.
On Friday, Casey and I went to TEE. After TEE I was able to meet with Dr. Chen, a pediatric cardiovascular surgeon, and arrange to shadow him during some of his surgeries the following week. Also, cell culture in molecular cardiology continues – I think I am getting better at it.