Cardiovascular Surgery 2-5

For anyone who wants to read the article on ECMO, it's called "Extracorporeal Lung Assist in Severe Respiratory failure and ARDS Current Situation and Clinical Application."

At the OPC, I learned that stens used for coronary artery surgery are not recommended for use in lower limb vessels b/c vessels of lower limbs lie within the muscles. Thus there's a concern that shear force/tearing force will break the stent and cause more serious issues. So for now if there's a stenosis of deep vessels of lower limb, only dilation technique is used. If stenosis repeats, dilate again. In some other countries like France, stent in lower limb vessels is used.

At the clinics, I found that a lot of patient with PAD have DM and also develop gangrene.

For the rest of my CV surgery week, I got to observe many embolectomy/thrombectomy procedures that precede dilation of vessels in patients who have had grafting. Dr. Chen removed the thrombi in patients' vessels then perform PTA balloon to dilate the stenotic vessels. In these cases, stenosis seems to be recurrent.

I also got to see PTA done on a branch of the circumflex and LAD done by a cardiologist. It was amazing! During the procedure, there was an acute thrombus and the surgeons were very calm and quick to remove it. It would have been a serious complication if they hadn't caught that thrombus. Talk about performing under pressure!

On Friday, Dr. Chen performed the AAA surgery. It was the 2nd AAA surgery ever performed at the hospital. I felt privileged to be there. Again, I was so amazed by the complexity of the surgery and the skills that Dr. Chen possesses. I was outside watching the surgery through a glass mirror and from a monitor, admiring modern medicine and technology which allow these kinds of procedures to be done, and a lot of people are saved. Before closing up the patient, Dr. Chen allowed me to be next to him to take a look at the incision site where it all began a couple of hours prior. The surgery went smoothly and ended beautifully with a round of applause.

During my CV surgery rotation, Dr. Chen reminds me that being a good surgeon is mostly about practice and improving one's skills. The intellect is important too, because it helps guide a surgeon's skills. But knowing everything in the textbook is not everything. Sometimes, you need to improvise during a surgery because nothing goes exactly like it is described in books. Surgery is like art; sometimes a good piece of art is purely improvising.

Cardiovascular Surgery - Day 1

I started out with a review on DVT. The 3 main causes of DVT are: 1. blood stasis 2. deficiency of coagulation system 3. trauma leading to injury of endothelium.

Dr. Chen discussed a very interesting topic. He told me that pulmonary emboli is not as a severe concern in Asian population as it is in Caucasian population. Asians, however, do not clot well so thrombolytic agents are used in lower dose. There are no solid research studies yet, but the doctors in many Asian countries all notice this pattern in their patients.

Note: tumor of pelvic area can have similar effects as DVT. CT scan is more sensitive to rule out tumor.

We also talked about how insurance will always affect doctor's decisions to what treaments will be given to patients. Whatever type of insurance a patient has, a doctor's responsibility is always find the best treatment that the patient can afford.

Then we talked about a case of abdominal aortic aneurysm.

Risk factors: smoking; genetic influences; atherosclerosis; infection; trauma; etc.

Criteria of for operation of aneurysm: 5cm or 1.5 x diameter of your normal size artery. If the aneurysm is less than 5cm or 1.5x diameter, then follow patient for 1/2 year. If the rate of increase is 5 mm in size in 6 months, then surgery is recommended.

I also learned about hybrid procedure. it combines minimally invasive coronary artery bypass surgery (TECAB or MIDCAB) with catheter-based coronary intervention(PTCA, stenting) (can read more on umm.edu/heart/hybrid.htm)

At the outpatient clinics, I saw many patients with PAD, with diabetes, gangrene (wet/dry), varicose veins

Some review:

PAD = obstruction of large arteries not within coronary, aortic arch vasculature or brain. Etiologies: atherosclerosis; stenosis; emboli; thrombus. Can cause acute or chronic ischemia.

Fontaine classification for chronic PAD: 1. claudication, incomplete blood vessel obstruction. 2. intermitten claudication 3. pain at rest, mostly feet, increase when elevate limbs (serious in PAD) 4. gangrene and difficulty walking (biological tissue loss)

5 P's for acute PAD: pain; paralysis; pale; pulseless; parathesis

Aortic dissection: inner wall of aorta causes blood to flow btw layers of wall of aorta and forces the layers apart. Classification: Stanford (A. ascending aorta and/or aortic arch, possible descending aorta B. descending aorta without involvement of ascending aorta or aortic arch)

First day in CV surgery was so much fun. I was lucky to see different presentation of PAD.