**4. Echocardiographic predictors in patients with severe aortic stenosis and poor left ventricular systolic function**

Left ventricular systolic function was shown as one of more important predictors of patients with AS. Patients with AS and LV systolic dysfunction have a poor prognosis if valve replacement is not performed. LV EF, as the most important conventional parameter for the LV global systolic function, was consistently reported as a postoperative prognostic factor in patients with severe AS. Patients with severe left ventricular dysfunction have increased intra-operative mortality, and there are yet contradictions about their improved outcomes after the AVR. Generally, the LV systolic dysfunction is not a contraindication to surgery. It was shown that patients who underwent AVR have a 5-year survival rate 60–70%, with a high operative mortality in the range of 10–15% for patients with LV systolic dysfunction. To predict the postoperative outcome of patients with severe AS and impaired LV function, the preoperative dobutamine stress echocardiography is useful technique. The presence of good contractile reserve in dobutamine stress echocardiography supports potential benefit from AVR and better outcome in these patients.

AVR decreases the LV afterload, through transvalvular pressure drop (Figure 2), resulting in regression of LV hypertrophy.

LV mass regression predominantly occurs within the first 6 months of surgery. Even there are few publications regarding the pre-operative echocardiographic predictors of LV functional recovery in AS patients with low EF, it justify the statement to consider these patients for the operation, after individual assessment of the patient, considering co morbidities and general conditions.

Recovery of LV function was evident after aortic valve replacement in the majority of patients with aortic stenosis and pre-operative LV dysfunction.

Patients with increased LV end-systolic dimension and/or LV systolic volume index seem to have less chance for the LV functional recovery. It seems that these patients loosed

Echocardiography in Severe Aortic Stenosis 29

They suggest that despite increased operative mortality, these patients should not be denied aortic valve replacement, given the substantial potential clinical benefit from AVR

In conclusion, in patients with severe aortic stenosis with impaired LV global systolic function, assessed by LV EF, AVR has significantly better outcome compared to those treated medically. These patients are likely to carry a high risk operation (up to 10%), than

**5. Echocardiographic predictors in patients with severe aortic stenosis and** 

Global LV function, assessed by conventional EF remains normal in most of AS patients. However, the long axis systolic function, assessed by M-mode echocardiography and/or tissue Doppler imaging (TDI) velocities, decreases even in patients with preserved EF. In AS patients with preserved EF, the longitudinal velocity, strain and strain rate are decreased and deteriorate further as AS become severe. These changes reflect that the LV myocardial dysfunction beginning at the subendocardium in early stages of AS and progress to midwall and to transmural contraction impairment in patients with severe AS. Recent studies have shown also that in patients with AS and preserved LV EF, the apical rotation and LV twist are increased and untwist is delayed compared to normals, as compensatory mechanisms for the increased intracavitary pressure overload and subendocardial ischaemia. Also, it was shown that these LV myocardial correlate with the severity of AS.

However, these compensatory mechanisms are lost after the LV EF deterioration.

overall integral ventricular function and to avoid potential clinical complications.

it lacks representing subendocardial component of the LV function.

damage becomes irreversible.

Strong evidence exists showing beneficial effect of AVR, not only in improving patients' symptoms but also in recovering, even partially, overall cardiac function. Improvement of LV ventricular function in these patients is interpreted on the basis of regression of myocardial hypertrophy, increased myocardial perfusion and hence overall cavity performance, at early and mid-term post-operative periods. While EF is the most popular measure of pre-operative LV systolic function in such patients, and surgical risk assessment

Severe aortic stenosis causes significant subendocardial dysfunction despite preserved ejection fraction. Aortic valve replacement surgery and removal of left ventricular afterload results in recovery of intrinsic subendocardial function within a week of surgery, well before mass regression and reverse remodeling. Such degree of pre-operative subendocardial disturbances may represent early changes that if ignored may substantiate and become irreversible. Thus, the presence of such abnormalities in symptomatic patients, even with normal ejection fraction, may suggest further evidence for a need for valve replacement in order to maintain

In patients with severe aortic stenosis and and maintained LV EF, the left ventricular twist is increased as compared with normal subjects suggesting a wall motion compensation for the reduced long axis motion in the aim to preserve LVEF. These motions alter towards normal values within six months of aortic valve replacement (Figure 3). These findings are growing evidence that on LV dysfunction and their improvement after AVR, even in asymptomatic patients, and may assist in identifying patients needing surgery before LV

to have a very poor prognosis for 10 years survival in medical treatment.

**preserved left ventricular systolic function** 

replacement.

contractile reserve, and up to now there is no evidence that they may improve LV systolic function after operation, and therefore we should less encourage these patients for the AVR. However, there are studies that have shown that even in patients with poor LV systolic function, there is still ability for a LV function recovery after AVR, explaining it through the mechanism of the markedly reduction of outflow tract resistance.

Studies have shown that stented and stentless valves have similar effect on the LV mass reduction after AVR in all patients that underwent this procedure, despite significant differences in indexed effective orifice area and peak flow velocity in favor of the stentless valve. However, in patients with AS and markedly reduced ventricular function, there was shown more rapid LV mass and function normalization in stentless patients compared to similar patients receiving a stented valve. The luck of large randomized studies for these prostheses makes even more difficult decision. However, a numerous retrospective studies have shown improvement in symptoms and LV EF in about 70% of the survivors after AVR in patients with low LV EF.

Fig. 2. Continues Doppler velocity of the aortic valve, in the same patient, two weeks after aortic valve replacement.

contractile reserve, and up to now there is no evidence that they may improve LV systolic function after operation, and therefore we should less encourage these patients for the AVR. However, there are studies that have shown that even in patients with poor LV systolic function, there is still ability for a LV function recovery after AVR, explaining it through the

Studies have shown that stented and stentless valves have similar effect on the LV mass reduction after AVR in all patients that underwent this procedure, despite significant differences in indexed effective orifice area and peak flow velocity in favor of the stentless valve. However, in patients with AS and markedly reduced ventricular function, there was shown more rapid LV mass and function normalization in stentless patients compared to similar patients receiving a stented valve. The luck of large randomized studies for these prostheses makes even more difficult decision. However, a numerous retrospective studies have shown improvement in symptoms and LV EF in about 70% of the survivors after AVR

Fig. 2. Continues Doppler velocity of the aortic valve, in the same patient, two weeks after

mechanism of the markedly reduction of outflow tract resistance.

in patients with low LV EF.

aortic valve replacement.

They suggest that despite increased operative mortality, these patients should not be denied aortic valve replacement, given the substantial potential clinical benefit from AVR replacement.

In conclusion, in patients with severe aortic stenosis with impaired LV global systolic function, assessed by LV EF, AVR has significantly better outcome compared to those treated medically. These patients are likely to carry a high risk operation (up to 10%), than to have a very poor prognosis for 10 years survival in medical treatment.
