Cardiovascular Critical Care I
Valvular
Disease Type
Management Considerations
Aortic stenosis
(AS)
| • | One of the most common and serious valvular diseases seen in the ICU |
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| • | As stenosis and disease progresses, severe/critical AS limits the heart to a fixed stroke |
volume; this inability to increase stroke volume occurs despite intrinsic or extrinsic attempts
to compensate (i.e., increased chronotropy or inotropy) and often only increases myocardial
oxygen demand without improving delivery
| • | Must be extremely cautious in approaching and reacting to invasive hemodynamic variables |
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(particularly cardiac output and cardiac index) – adding agents with inotropic/chronotropic
effects may expedite demand ischemia and an acute MI because of the physiologic inability
to increase cardiac output with a fixed partial LV outflow tract obstruction
| • | For reasons similar to those previously listed, treating hypertension with afterload-reducing |
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agents must be done judiciously because as afterload (SVR) decreases, cardiac output cannot
increase
| • | Can coexist with concurrent aortic insufficiency/regurgitation because the stenotic or |
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calcified valve leaflets may no longer move and come together (coapt) well
| • | These patients may be at risk of developing mitral regurgitation and subsequent increases in |
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left atrial pressures (increasing risk of AF) because of increased LV filling pressures
| • | Must be cautious in decreasing HR in sinus tachycardia because this can be a primary means |
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of compensation
| • | Patients need adequate preload; however, they can become symptomatic even with slight |
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volume overload. As an example, atrial fibrillation can be very detrimental simply because it
decreases preload to the ventricle
| • | Patients with severe aortic stenosis and systolic HF (described as low output – low gradient) |
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have a poorer prognosis
Aortic
regurgitation
(AR)
| • | Also known as aortic insufficiency (AI) |
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| • | Must be cautious in decreasing HR in sinus tachycardia because this can be a primary means |
of compensation to maintain adequate cardiac output
| • | Patients need adequate preload, but the predominant target is to maintain decreased afterload |
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(SVR) to facilitate forward blood flow and cardiac output
Mitral stenosis
(MS)
| • | Contributes to decreased LV filling and increased left atrial pressures; can increase risk of |
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AF and secondary pulmonary hypertension
| • | Increasing diastolic filling time and avoiding tachycardias can facilitate stabilization until |
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valve is corrected
| • | Use of selective pulmonary vasodilators (i.e., inhaled nitric oxide or inhaled epoprostenol) |
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may be detrimental because these agents can facilitate pulmonary congestion, given the
preexisting pulmonary venous hypertension and elevated left atrial pressures
| • | Can coexist with concurrent mitral regurgitation because the stenotic or calcified valve |
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leaflets may no longer move and coapt well
Mitral
regurgitation
(MR)
| • | Primary clinical target is to decrease LV afterload (SVR) to minimize augmentation of MR |
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and to facilitate forward blood flow. If SVR is too high, blood will travel in the path of least
resistance until an adequate LV pressure is generated to open the aortic valve (must exceed
the systemic diastolic blood pressure)
| • | Use of selective pulmonary vasodilators (i.e., inhaled nitric oxide or inhaled epoprostenol) |
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may be detrimental because these agents can facilitate pulmonary congestion, given the
preexisting pulmonary venous hypertension and elevated left atrial pressures