Miscellaneous

Question 1

Type IIA VonWillibrand Syndrome cause

Answer 1

Shear stress from AS or LVAD causes ADAMTS-13 mediated proteolysis of highest molecular weight multimeters preventing collagen and platelet binding to vascular injury.

Question 2

ScvO2 vs SvO2

Answer 2

ScvO2 is from SVC (usually 3% lower than SvO2 because head extracts more O2 than the lower body)

SvO2 is from proximal pulmonary artery

Question 3

What is the root cause of all hypoxia?

Answer 3

V/Q mismatch

Question 4

What % of RV ejection depends on LV contraction?

Answer 4

Up to 40%

Question 5

How does iNO work?

Answer 5

NO diffuses rapidly into pulmonary vasculature smooth muscle and activates guanylate cyclase, stimulating the production of cGMP which leads to smooth muscle relaxation. Since iNO is rapidly scavenged by hemoglobin, it exerts its action in primarily well-ventilated regions of the lungs, improving V/Q matching. By relaxing pulmonary vasculature, it also helps reduce PVR but has a more focused effect than intravenous vasodilators.

Of note, NO reacts with oxyHgb to form metHgb and nitrate but this only becomes clinically significant at >80ppm.

Question 6

What are the 3 types of cardiac MRI imaging?

Answer 6

• Late Gadolinium Enhancement
• T1
• T2

Question 7

Define cardiac afterload

Answer 7

The ventricular wall stress during systole or ejection

Question 8

Definition of standard of care

Answer 8

The actions of a similarly trained, reasonable, prudent physician