**2. Diagnostic tools**

## **2.1 Echocardiography**

Echocardiography is the cornerstone in identification and follow-up of aortic stenosis. It visualizes the calcification of the aortic valve, and the Doppler technique quantifies the left ventricular outflow gradient [1]. The aortic valve area can be estimated by calculation or planimetry but must be considered in conjunction with the mean gradient, wall thickness, ejection fraction, ventricular dimension, valve calcification, and hemodynamic parameters at the time of exam.

Four classes of aortic stenosis can be described:


## **2.2 Exercise test**

Evaluation of symptoms is related to the aortic stenosis that can be refined at an exercise test, typically ergometer bicycle test [4]. Using echocardiography at pharmacologically induced stress may reveal an increase in the pressure gradients [5]. Furthermore the response of ventricular function at exercise may give valuable information.

#### **2.3 Miscellaneous imaging techniques**

Multislice computerized tomography is nowadays an established method for quantification of valve calcification which is important in patients with low gradients. Furthermore computerized tomography offers excellent visualization of the aorta beyond the first part, the root. This is crucial in determination of preoperative anatomical assessment.

#### **2.4 Laboratory markers**

NT-proBNP is useful in follow-up of patients with aortic stenosis and is a complementary tool between intervals of echocardiography [6, 7].

#### **3. Follow-up**

Patients with aortic stenosis who are asymptomatic should undergo reevaluation every 6 months and should be asked to inform their physician the case of onset of symptoms. In mild to moderate aortic stenosis, evaluation every 3 years is reasonable but more often if significant calcification is assessed.

### **4. Treatment**

#### **4.1 Aortic stenosis without symptoms**

While symptomatic severe aortic stenosis should be recommended intervention as rule of thumb, patients without symptoms are controversial. Still, the presence of an unequivocal severe aortic stenosis has not been proven to benefit from early intervention [8, 9]. Patients with reduced ejection fraction deemed to be secondary to aortic stenosis should not be refrained from an intervention. It is also reasonable to recommend intervention in cases of exercise-induced symptoms attributed to stenosis [10]. In the careful evaluation of asymptomatic patients, the following factors can be taken into account: massive hypertrophy, abnormal longitudinal left ventricular function, and pulmonary hypertension.

**3**

*Introductory Chapter: Aortic Stenosis*

**4.2 Pharmacological approach**

**4.3 Interventional approach**

second sternotomy.

**4.4 Anatomical aspects: TAVI vs. SAVR**

are factors likely to favor TAVI.

hypertrophic cardiomyopathy.

**5. Future perspectives**

**4.5 Cardiac and extra-cardiac aspects: TAVI vs. SAVR**

*DOI: http://dx.doi.org/10.5772/intechopen.86521*

rate/rhythm control if atrial fibrillation occurs.

Pharmacological therapy, including statins, has no impact on the disease progression in aortic stenosis. Nevertheless, concomitant hypertension should be treated. Patients who deteriorate into reduced ejection fraction should be subject to current heart failure optimization including beta-blocker, angiotensin-converting enzyme blocker/angiotensin receptor blocker, aldosterone receptor blocker, and

A patient with symptoms due to severe aortic stenosis should be evaluated for an interventional treatment. This is the only approach that will improve survival and relieve symptoms. In patients with an overall life expectancy of <12 months based

The interventional mode is either surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI). Based on the European Society Guidelines, a STS/EuroSCORE ≥4% favors TAVI and patients younger than 75 years based on limited long-term follow-up data of TAVI. In elderly patients, severe comorbidities (pulmonary or renal), considerable frailty, and those with restricted mobility, TAVI is preferred. In patients who previously underwent open-chest heart surgery, TAVI is advantageous due to adherent tissue which may complicate a

There are several factors that may be taken into account when choosing between

TAVI and SAVR. A possible arterial approach is almost a prerequisite for TAVI, even though alternative routes may be an option. TAVI is the preferred method in patients who have sequele after chest radiation, porcelain aorta, risk of damage to grafting anastomosis following bypass surgery, and chest deformation. On the contrary, aortic root malfunction, thrombi in the aorta, and valve prosthesis mismatch

SAVR should be performed in the case of concomitant need of other valve surgeries, aneurysm of the aorta, and septal hypertrophy requiring myectomy in

The individual risk should be assessed after careful evaluation and discussed between team members. The local resources and experience are important to be taken into account. In patients with high risk, TAVI is superior [11, 12]. Recently additional evidence points in the direction to favor TAVI in the majority of cases even in patients with low risk [13]. Notably, significant vascular complications, need of pacemaker implantation, and paravalvular regurgitation are more frequent for TAVI [14, 15]. SAVR is associated with more severe bleeding, acute renal failure, and atrial fibrillation. The risk of ischemic stroke seems to be similar [14, 15].

The technical advancement of TAVI is expected to improve, and the increased volume is likely beneficial. However, long-term results over the decades are still

on irreversible comorbidities, a conservative management is advocated.
