**3. Anterior right mini-thoracotomy**

To consider this approach, a preoperative chest computed tomography (CT) scan is mandatory to assess the relationship of intrathoracic structures, especially the distance of the aortic root to the right-sided rib cage. The main criteria are: (1) the position of more than half of the ascending aorta is over the pulmonary artery on the right side of the sternum and (2) the distance of the ascending aorta from the sternum is <10 cm [7, 8]. Over the 2nd right intercostal space, a <10 cm long incision is made with the medial portion at the sternal edge. The intercostal muscles are sharply divided using electrocautery. Upon entering the thoracic cavity, the superior right pulmonary lobe is retracted using selective bilateral lung intubation and prophylactic division of the RITA is necessary to prevent extensive blood loss. A small-blade retractor is inserted and the pericardium is opened in a longitudinal matter (**Figure 6**) [5]. It is of paramount importance to identify the phrenic nerve before pericardial incision to avoid postoperative delayed mechanical ventilation due to respiratory disturbances. Two stay sutures on both sides are applied and the intrapericardial contents are lifted upwards. We advise against routine rib resection. In most ART cases, visualization is already satisfactory after intercostal muscles' division.

The cardiopulmonary bypass could be established centrally or peripherally. At our institutions, central cannulation remains the preferred option. The rest of the operation commences in a similar fashion as previously described in the chapter on upper mini-sternotomy [9, 10].

**Figure 6.** *Pericardial incision through an anterior right mini-thoracotomy [5].*

## **4. Outcomes**

Both already described minimally invasive approaches to the aortic valve were developed in the 1990s. The Cleveland group developed the upper mini-sternotomy technique in 1996 [4] and the first published data on the ART are from New Delhi group from 1993 [9].

The first large published article regarding minimally invasive aortic valve surgery was written by the Boston group. They reported their experience with 526 consecutive minimally invasive aortic valve procedures, which were mostly done through an upper mini-sternotomy (93%). Their publication has shown excellent results with short- and long-term mortality at 2% and 5%, respectively. Freedom from reoperation at 6 years was 99% [6].

Encouraged by these data, the number of minimally invasive aortic valve surgery have risen significantly in the following years. A report was recently published on the clinical trends between median sternotomy and minimally invasive approaches for aortic valve stenosis in three high volume aortic valve surgery centres in the USA (Houston, Atlanta, and Miami). In the observed three-year period, the overall number of AVRs increased by 107% owing to improved diagnostics and TAVIs for previously denied patients. Minimally invasive AVRs increased by 57% and median sternotomy AVRs decreased by 15% [11].

Outcomes of minimally invasive aortic valve surgery are similar or even superior in some reports to those of conventional median sternotomy surgery [12].

### **4.1 Mortality**

Mortality rates are similar when comparing ART [13–15] or upper mini-sternotomy [6, 16, 17] with median sternotomy, respectively. One-year survival is reported to be >95%, whereas 5-year survival ranges from 80–95%, respectively.
