valvular disorder part II

Question 1

cardiac remodeling in mitral stenosis

Answer 1

• reduced filling of LV = low LVEDP and LV volume

- RA and RA dilation impairs LV ejection

Question 2

values for mild, moderate, server mitral stenosis

Answer 2

mild > 1.5 cm2
mod 1-1.5 cm2
severe > 1 cm2

Question 3

Goal directed intraoperative management of mitral stenosis (LV preload, Rate, contractility, SVR, PVR)

Answer 3

LV preload: high 
rate: low, sinus
contractillity: even
SVR: even
PVR: low

Question 4

why is it important to keep LV preload high in mitral stenosis

Answer 4

adequate preload is necessary for forward flow of VS existing LAP and danger of pulmonary edema

Question 5

Things to avoid intraoperatively with mitral stenosis

Answer 5

hypoxia, hypercapnea, tachycardia

Question 6

what should you do if an arrythmia develops in a pt with mitral stenosis

Answer 6

cardiovert if necessary

Question 7

LV filling takes place during _____

Answer 7

diastole

Question 8

PA monitoring for a patient with mitral stenosis?

Answer 8

PA cath with caution

increased risk of rupture of PA d/t thin walled pulmonary arteries

Question 9

in patients with mitral stenosis seperation from bypass may reveal _____ how is treated

Answer 9

may reveal underlying RV and LV dysfunction treat with volume and inotropes

Question 10

prophylactic treatment prior to maze procedure

Answer 10

amiodarone

Question 11

causes of mitral regurgitation

Answer 11

mitral valve leaflet abnormalities, mitral annulus dilation, disproportionate LV elargement

Question 12

etiology of acute MR

Answer 12

• papillary muscle dysfunction or rupture due to ischemia
• blunt chest trauma
• infective pericarditis

Question 13

etiology of chronic MR

Answer 13

• mitral annulus dilation from ishcemic cardiomyopathy or AI
• mitral leaflet disorders
• disorders of subvalvular apparatus (chordae tendenae)

Question 14

pathophysiology acute MR

Answer 14

• marked left atrial overload
• pulmonary congestion
• sympathetic activation, tachycardia, incrased SVR, increased contractility, worsening ischemia, biventricular failure

Question 15

pathophysiology of chronic MR

Answer 15

• LAE, eccentric hypertrophy from relative increased volume preserves forward flow by increased SV
• LAE frequently causes a-fib, loss of volume
• worsening of disease causes pumonary congestion, increase PAP, RV failure eventually

Question 16

remodeling in MR

Answer 16

acute: LVEDP rapidly increases and dilates left atrium to maintain stroke volume
Chronic: dilation occurs slowly, eccentric hypertrophy occurs. maintain forward flow by increaseing overall SV in the presence of a regurgitant percentage

Question 17

severity of regurg (mild, mod, severe)

Answer 17

mild 40%

Question 18

goal directed intraoperative management of MR

LV preload, rate, contracility, SVR, PVR

Answer 18

LV preload: high or low 
Rate: even or high
Contractility: even
SVR: low
PVR: low

Question 19

LV preload in MR

Answer 19

maintenance of preload frequently helps to maintain forward flow. however this depends on the patient. dilation of the LA in some folks also dialtes the annulus and actually increases regurg. must base decisions on patient response to a fluid challenge

Question 20

anesthetic managmenet

Answer 20

• light premed
• induction: peripheral vasodilation, good contractility, HR 90
• PA
• TEE
• nitric oxide - pulm vasodilator
• hyperventilation will decrease PA pressures
• once new valve in place LV may have a hard time ejecting a full SV on separation from bypass

Question 21

problem with inadequate anesthesia for intuabation in MR

Answer 21

may cause sudden sympathetic outflow increase regur and cause pulm edema