valvular disorder part II Flashcards
cardiac remodeling in mitral stenosis
- reduced filling of LV = low LVEDP and LV volume
- RA and RA dilation impairs LV ejection
values for mild, moderate, server mitral stenosis
mild > 1.5 cm2
mod 1-1.5 cm2
severe > 1 cm2
Goal directed intraoperative management of mitral stenosis (LV preload, Rate, contractility, SVR, PVR)
LV preload: high rate: low, sinus contractillity: even SVR: even PVR: low
why is it important to keep LV preload high in mitral stenosis
adequate preload is necessary for forward flow of VS existing LAP and danger of pulmonary edema
Things to avoid intraoperatively with mitral stenosis
hypoxia, hypercapnea, tachycardia
what should you do if an arrythmia develops in a pt with mitral stenosis
cardiovert if necessary
LV filling takes place during _____
diastole
PA monitoring for a patient with mitral stenosis?
PA cath with caution
increased risk of rupture of PA d/t thin walled pulmonary arteries
in patients with mitral stenosis seperation from bypass may reveal _____ how is treated
may reveal underlying RV and LV dysfunction treat with volume and inotropes
prophylactic treatment prior to maze procedure
amiodarone
causes of mitral regurgitation
mitral valve leaflet abnormalities, mitral annulus dilation, disproportionate LV elargement
etiology of acute MR
- papillary muscle dysfunction or rupture due to ischemia
- blunt chest trauma
- infective pericarditis
etiology of chronic MR
- mitral annulus dilation from ishcemic cardiomyopathy or AI
- mitral leaflet disorders
- disorders of subvalvular apparatus (chordae tendenae)
pathophysiology acute MR
- marked left atrial overload
- pulmonary congestion
- sympathetic activation, tachycardia, incrased SVR, increased contractility, worsening ischemia, biventricular failure
pathophysiology of chronic MR
- 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
remodeling in MR
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
severity of regurg (mild, mod, severe)
mild 40%
goal directed intraoperative management of MR
LV preload, rate, contracility, SVR, PVR
LV preload: high or low Rate: even or high Contractility: even SVR: low PVR: low
LV preload in MR
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
anesthetic managmenet
- 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
problem with inadequate anesthesia for intuabation in MR
may cause sudden sympathetic outflow increase regur and cause pulm edema
