Assessment of Mixed Valvular Disorders Flashcards
In case of mixed moderate or severe stenosis and moderate or severe regurgitation of the same valve, that is, MS + MR and AS + AI, one lesion usually predominates over the other (stenosis or regurgitation), and the pathophysiology resembles the ______________ lesion.
The _________________ lesion worsens the effect and the symptomatology of the dominant lesion, and these patients are more prone to have increased PCWP and pulmonary edema than patients with isolated stenosis or regurgitation.
In case of mixed moderate or severe stenosis and moderate or severe regurgitation of the same valve, that is, MS + MR and AS + AI, one lesion usually predominates over the other (stenosis or regurgitation), and the pathophysiology resembles the dominant lesion.
However, the nondominant lesion worsens the effect and the symptomatology of the dominant lesion, and these patients are more prone to have increased PCWP and pulmonary edema than patients with isolated stenosis or regurgitation.
Effect on transvalvular gradient in patients with mixed stenosis and regurgitation?
Overestimation by gradient
Underestimation by valvular area
Because the flow across the valve is increased, the transvalvular gradient is increased in comparison with valvular stenosis sis without regurgitation
This leads to overestimation of the anatomic severity of the stenosis when assessed by gradient. The gradient, however, correlates with the physiological consequences of the mixed stenosis-regurgitation.
The valvular area may be underestimated, that is, the stenosis may appear more severe, if Gorlin’s equation is used with the net forward Fick or thermodilution cardiac output rather than the total output across the valve
The ________________ tends to mask the severity of the more distal lesion by reducing the flow across the distal lesion, whereas the distal lesion tends to _______________ the hemodynamic effect of the proximal lesion because of increased backward volume and/or pressure.
Proximal lesion
Exacerbate
Hemodynamics of severe MR or MS associated with AS
AS worsens the hemodynamic effects of MS or MR and may worsen the severity of MR (from moderate to severe).
In case of combined MR and AS, the LV is exposed to both pressure and volume overload in systole.
The severity of AS may be underestimated by gradient assessment as a result of low cardiac output but may be overestimated by AVA
Hemodynamic effects of severe MS with AI
The hemodynamic effect of MS is exacerbated. In order to allow transmitral flow, LA pressure has to increase in parallel to the increase in LV diastolic pressure.
On the other hand, the hemodynamic effect of AI is reduced.
Hemodynamic effects of MR-AI
Combined MR-AI is the most poorly tolerated combination. LV gets a double volume load in diastole; LV and LA filling pressures and volumes are more severely increased than with each lesion alone. T
Hemodynamic effects of severe AS–moderate-to-severe MR
MR is often functional related to the LV pressure overload and often improves after aortic valve surgery.
MR is worsened by AS, and AS severity may be underestimated by gradient assessment because of the low flow secondary to MR. However, AVA calculation using Gorlin’s equation is not affected by MR.
