**1. Introduction**

150 Aortic Valve Surgery

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Valvular surgery in octogenarians: operative risks factors, evaluation of Euroscore

B, Fabri BM. Limitations of additive EuroSCORE for measuring risk stratified mortality in combined coronary and valve surgery. Eur J Cardiothorac Surg 2004; Aortic valve disease is a fatal disease with but a single cure. Removal of the mechanical obstruction in aortic stenosis (surgery or TAVI) and replacement of an incompetent valve (so far only surgery) are the only treatment options.

While aortic valve replacement in patients with isolated valve disease and normal pumpfunction of the heart has become a routine procedure and is performed with excellent results all over the world, it can be a rather challenging procedure in severely ill patients with heart failure and comorbidities. Patients with low ejection fraction are one of the most challenging patient groups in cardiac surgery.

According to the guidelines for the management of patients with valvular heart disease as recommended by all major heart associations including the European Society of Cardiology, American College of Cardiology, American Heart a ventricular function reduced to below 50% ejection fraction is considered a class I, level of evidence B and C indication respectively for aortic valve surgery. (ACC/AHA 2006 Guidelines for the

Management of Patients With Valvular Heart Disease, Bonow et al., 2006) Despite this fact there is a high number of patients presenting with severely reduced ventricular function for aortic valve surgery.

In aortic insufficiency 70% have a function reduced to below 50% and around 10% present with a significantly reduced function of less than 30% EF. In case of aortic stenosis the numbers are a less dramatic but still more than 40 % of patients referred for valve surgery have an ejection fraction below 50%.

This is due to the fact that aortic valve disease can go unnoticed for a very long time resulting in heart failure at time of presentation. Another fact is that at least some patients are treated conservatively for a too long period of time until their EF deteriorates.

Apart from that, due to the demographic development there is an increasing number of patients with aortic valve disease and advanced age resulting in a high number of elderly patients with more comorbidities and reduced ejection fraction.

#### **2. Impaired ventricular function**

In the scientific literature there are various definitions with different thresholds describing impaired ventricular function in patients undergoing aortic valve surgery. Ali and co-workers

Aortic Valve Surgery and Reduced Ventricular Function 153

have AR and already have severe LV dysfunction, an important issue to consider is whether

Table 1. Comparision of pre- and postoperative echocardiographic values (Chaliki et al. 2002) Natural history studies have focused mainly on asymptomatic patients with normal function. In a recent study patients were stratified according to their ejection fraction and it was demonstrated that those with markedly lower EF had a higher rate of congestive heart

The outcome of conservatively treated patients with even mild LV dysfunction is poor. Indeed, patients with either EF 55% or LV systolic dimension 25 mm/m2, even if asymptomatic at presentation, have excessive long-term mortality rates if treated conservatively. Although patients with severe LV dysfunction could not be analyzed specifically, the uniform risk increase with decreasing EF under conservative treatment suggests that such patients are at very high risk if not operated on and that an aggressive

Sionis et al. even evaluated if it is beneficial to offer these patients cardiac transplantation instead of performing aortic valve replacement. But they conclude from their data of only 27 patients that while the mortality of patients with aortic valve insufficiency and impaired ventricular function undergoing aortic valve replacement is high, it is not excessively high justifying listing for transplantation. Additionally a lot of these patients do not develop

Conversely, although patients with a markedly low EF and severe AR are at high risk, their medium-term outcome is not uniformly ominous. The usual operative mortality rate reported for AVR ranges from 1% to 7%. Chaliki et al. show excessive operative mortality rates among patients with markedly low EF, but it is not overwhelming. A majority of patients remain free of heart failure 10 years after AVR. Therefore, a notable period of eventfree survival can be achieved in most patients after correction of AR despite their very low preoperative EF. The functional status of most patients improves after surgery, irrespective of preoperative EF. Thus, a markedly low EF (<35%) is not, in our judgment, a

In light of the fact that patients with aortic insufficiency and reduced ejection fraction do not benefit from aortic valve replacement regarding pump function it would be necessary to reevaluate the guidelines for aortic valve replacement in those patients, since currently AVR in asymptomatic patients is only recommended when EF declines down to <50% or end-

failure than patients who had moderately reduced or normal EF before AVR.

heart failure and therefore still benefit from AVR. (Sionis et al., 2010)

AVR represents too high a risk and conservative treatment is preferable.

reprint from Chaliki HP, et al. 2002 with permission of Circulation

approach is justified.

contraindication to AVR. (Chaliki 2002)

define reduced left ventricular ejection fraction as <60%, which is in fact an unusual cut off level. (Ali et al., 2006)

Sharony et al. included patients with an ejection fraction < 40% in their study on aortic valve replacement in patients with impaired ventricular function. (Sharony et al., 2003) Mihaljevic T. et al. used a more complex system including 5 subgroups according to cardiac pumpfunction. Impairment of LV function was graded qualitatively as follows: EF 50% or greater, none; EF 40% to 49%, mild EF 35-39% moderate; EF 26%-34% moderately severe, and EF 25% or less, severe. They demonstrated the prognostic value of this grading system in previous studies. (Mihaljevic T. et al., 2008) For the sake of clearness of this book chapter we include scientific studies with a cut off level of less than 40% and cite the exact values as described in the respective publications.
