Mediziniche Hotschule Part II

VAD implantation is a great procedure, however there are some downsides.  Patients must always carry around their 2.2 kg control/power mechanisms, they are bombarded each day with checkup calls from medical staff, and their drive lines are associated with a high risk of infection.  Since the drive lines lead right to the heart from the outside of the body, physicians refer to these drive lines as infection highways to the heart.  The patients must be on anticoagulants for the rest of their lives as embolisms are a common occurrence since the VAD rotors cause hemolysis and blood clots are extremely dangerous and can lead to stroke or myocardial infarction.

                After the VAD lecture, Dr. Hanke took us to see some of her patients in ward 15.  In one patient, we were given the opportunity to listen the whirring of their LVAD using a stethoscope.  In another patient, whom we would later in the day watch as he received a VAD implantation, we examined his symptoms of left heart failure.  His symptoms included edema as a result of decompensation altering the pressure dynamics in his blood vessels causing fluid to leak into the interstitial spaces of his body.  Gravity pulled the fluid into his hands and feet causing them to become very swollen, a symptom known as pedal edema.  Fluid accumulated in his abdominal region, a symptom known as ascites, and in his face as well.  His cheeks were also purple.  When blood cells are saturated with oxygen, they gain a bright red color and, when they do not contain oxygen, they are a dark purple color.  Since the cheeks are a very thin layer of epithelial cells, the color of blood passing through the vessels behind them is visible and indicates the blood’s oxygen saturation.  The purple color indicates the blood moving through them did not contain oxygen.  This can be attributed to many things, but in this case it was likely edema in the pulmonary arteries was inhibiting gas exchange in the alveoli.

                Once we finished meeting some of the patients, we scrubbed in at the OR and watched two procedures, a valve replacement, and a coronary artery bypass graft, or CABG.  Both procedures were high risk, so we had to watch from the far side of the room.  It was an experience being able to watch the surgeons as they performed the operation, however as we were far away from the action, not much was learned of the operations themselves.  After, watching parts of the two procedures, we put on our regular clothes and went back upstairs to debrief with Dr. Hanke.  Interestingly enough, the day before this trip to the Hanover hospital, I had gone to a biomedical research facility and learned about catheterized valve replacements.  The engineers who were working on creating the catheterized valves were very enthusiastic about them and their reliability in vivo.  The valve replacement we watched was not catheterized and was relatively much more invasive than the alternative as they had to crack the sternum and open the thoracic cavity to expose the heart.  I asked Dr. Hanke if she had ever performed a catheterized valve replacement and she replied she had, however that they were not very effective.  I learned they were not very effective for one particular reason.  They were performed only on patients who were too weak to survive a more invasive procedure.  For this reason, the data they have on the catheterized valve replacement procedures may not be reliable because the patients receiving them are in a worse condition to begin with as opposed to their more healthy counterparts receiving the valve replacements in the more traditional fashion.