**Figure 2.**

*Left: endoaortic cross-clamping with an endoaortic balloon. Right: transthoracic cross-clamping using a Chitwood clamp.*

endoaortic balloon, which comprises a triple lumen catheter mostly introduced usually through a left femoral artery with an inflatable balloon at the tip. The central lumen is used for delivery of cardioplegia and aortic root vent. The remaining lumen is used for balloon inflation and deflation as well as pressure monitoring. The transthoracic clamp is called Chitwood clamp, and is introduced through the intercostal space and positioned around the aorta.

Maselli et al. monitored embolic events with a transcranial Doppler during minimally invasive mitral valve surgery, and found that brain embolism occurred predominantly at the time of ascending aorta clamping and declamping with an endoaortic balloon [17]. In the meantime, the application of an external crossclamp to the ascending aorta may cause the embolic events and traumatic injury.

The superiority between two methods of aortic cross-clamp has been controversial.

Kowalewski et al. performed a meta-analysis of observational studies [18]. They found that there was no difference of cerebrovascular events, all-cause mortality, and kidney injury between endoaortic and transthoracic cross-clamp; however, endoaortic balloon occlusion was associated with a higher risk of iatrogenic aortic dissection (0.93 vs. 0.13%) and higher risk of leg ischemia (0.47 vs. 0.20%) than transthoracic cross-clamp.

Kesavuori et al. reported their initial 5-year results of robotic mitral valve repairs [19]. The postoperative complications included conversion to sternotomy, reoperations for bleeding, and low cardiac output states requiring extracorporeal membrane oxygenation. They reported that early major robotic complications were related to the use of endoaortic balloon occlusion.

In the meantime, Barbero et al. reviewed three centers' experience of minimally invasive mitral valve surgery, and did not find differences in respiratory failure, major vascular complication, stroke, and in-hospital mortality between endoaortic and transthoracic aortic clamping [20].

#### **2.5 Myocardial protection**

Although several ways of myocardial protection have been advocated in minimally invasive mitral valve surgery, the optimal method has been controversial. There is a choice of antegrade or retrograde, intermittent or continuous, and crystalloid or blood cardioplegia.

One of the earliest approaches were antegrade cardioplegia via the endoaortic balloon, as described in the "aortic cross-clamp." Lebon et al. compared 118 patients undergoing minimally invasive mitral valve surgery and 118 patients undergoing open mitral valve surgery, and found no difference in the incidence of difficult weaning from bypass and intra-aortic balloon pump use between two groups [21].

When applying transthoracic cross-clamp, direct cardioplegia insertion into the ascending aorta through a long antegrade cardioplegia catheter is necessary. As the insertion site of cardioplegia catheter gets far in the thoracotomy, the insertion and decannulation of the catheter can be associated with higher risk of bleeding than sternotomy.

In the setting of aortic insufficiency, retrograde cardioplegia might be desirable. Retrograde cardioplegia can be performed by placement of a percutaneous coronary sinus catheter via the internal jugular vein, but that requires specialized skills with an increased cost of a specialized catheter. In addition, the retrograde cardioplegia catheter insertion can cause catheter displacement, coronary sinus rupture, and inadequate protection of the right ventricle [22]. Another option of retrograde cardioplegia is to directly insert a catheter through a purse-string in the right atrium under a transesophageal echocardiography.

**29**

**Figure 3.**

*Tips and Pitfalls in Robotic Mitral Valve Surgery DOI: http://dx.doi.org/10.5772/intechopen.85241*

**2.6 Unilateral pulmonary edema**

sion, and hemodynamic instability.

There are two types of cardioplegia solution: crystalloid and blood. Blood cardioplegia is usually chosen in the open-heart surgery, as it has two advantages over pure crystalloid cardioplegia. First, blood cardioplegia can deliver oxygen to the myocardium, and secondly, the additional crystalloid volume is small; thus, hemodilution or myocardial edema can be avoided. Therefore, some centers still use

However, some centers prefer crystalloid-based cardioplegia: histidine-tryptophan-ketoglutarate cardioplegia [19, 23]. The advantage of this cardioplegia is that a single antegrade shot can maintain adequate myocardial protection up to 2 hours; thus, potentially aortic cross-clamp time and cardiopulmonary bypass time can be reduced.

Unilateral pulmonary edema is known as an uncommon, but frequently lethal complication following minimally invasive robotic cardiac surgery. The clinical presentation of this condition includes severe right lung edema developing within the first several minutes to hours after coming off from a cardiopulmonary bypass (**Figure 3**), which leads to profound hypoxia, hypercapnia, pulmonary hyperten-

The mechanism of this condition is yet to be fully understood. Lung deflation is shown to be associated with the sequestration of inflammatory response. Minamiya et al. reported that during atelectasis, polymorphonuclear leukocytes accumulate in

blood cardioplegia in minimally invasive mitral valve surgery.

*A typical chest X-ray imaging showing unilateral pulmonary edema on the right side.*

*Tips and Pitfalls in Robotic Mitral Valve Surgery DOI: http://dx.doi.org/10.5772/intechopen.85241*

*Cardiac Surgery Procedures*

controversial.

transthoracic cross-clamp.

**2.5 Myocardial protection**

crystalloid or blood cardioplegia.

under a transesophageal echocardiography.

endoaortic balloon, which comprises a triple lumen catheter mostly introduced usually through a left femoral artery with an inflatable balloon at the tip. The central lumen is used for delivery of cardioplegia and aortic root vent. The remaining lumen is used for balloon inflation and deflation as well as pressure monitoring. The transthoracic clamp is called Chitwood clamp, and is introduced through the

Maselli et al. monitored embolic events with a transcranial Doppler during minimally invasive mitral valve surgery, and found that brain embolism occurred predominantly at the time of ascending aorta clamping and declamping with an endoaortic balloon [17]. In the meantime, the application of an external crossclamp to the ascending aorta may cause the embolic events and traumatic injury. The superiority between two methods of aortic cross-clamp has been

Kowalewski et al. performed a meta-analysis of observational studies [18]. They found that there was no difference of cerebrovascular events, all-cause mortality, and kidney injury between endoaortic and transthoracic cross-clamp; however, endoaortic balloon occlusion was associated with a higher risk of iatrogenic aortic dissection (0.93 vs. 0.13%) and higher risk of leg ischemia (0.47 vs. 0.20%) than

Kesavuori et al. reported their initial 5-year results of robotic mitral valve repairs [19]. The postoperative complications included conversion to sternotomy, reoperations for bleeding, and low cardiac output states requiring extracorporeal membrane oxygenation. They reported that early major robotic complications were

In the meantime, Barbero et al. reviewed three centers' experience of minimally invasive mitral valve surgery, and did not find differences in respiratory failure, major vascular complication, stroke, and in-hospital mortality between endoaortic

Although several ways of myocardial protection have been advocated in minimally invasive mitral valve surgery, the optimal method has been controversial. There is a choice of antegrade or retrograde, intermittent or continuous, and

One of the earliest approaches were antegrade cardioplegia via the endoaortic balloon, as described in the "aortic cross-clamp." Lebon et al. compared 118 patients undergoing minimally invasive mitral valve surgery and 118 patients undergoing open mitral valve surgery, and found no difference in the incidence of difficult weaning from bypass and intra-aortic balloon pump use between two groups [21]. When applying transthoracic cross-clamp, direct cardioplegia insertion into the ascending aorta through a long antegrade cardioplegia catheter is necessary. As the insertion site of cardioplegia catheter gets far in the thoracotomy, the insertion and decannulation of the catheter can be associated with higher risk of bleeding than

In the setting of aortic insufficiency, retrograde cardioplegia might be desirable. Retrograde cardioplegia can be performed by placement of a percutaneous coronary sinus catheter via the internal jugular vein, but that requires specialized skills with an increased cost of a specialized catheter. In addition, the retrograde cardioplegia catheter insertion can cause catheter displacement, coronary sinus rupture, and inadequate protection of the right ventricle [22]. Another option of retrograde cardioplegia is to directly insert a catheter through a purse-string in the right atrium

intercostal space and positioned around the aorta.

related to the use of endoaortic balloon occlusion.

and transthoracic aortic clamping [20].

**28**

sternotomy.

There are two types of cardioplegia solution: crystalloid and blood. Blood cardioplegia is usually chosen in the open-heart surgery, as it has two advantages over pure crystalloid cardioplegia. First, blood cardioplegia can deliver oxygen to the myocardium, and secondly, the additional crystalloid volume is small; thus, hemodilution or myocardial edema can be avoided. Therefore, some centers still use blood cardioplegia in minimally invasive mitral valve surgery.

However, some centers prefer crystalloid-based cardioplegia: histidine-tryptophan-ketoglutarate cardioplegia [19, 23]. The advantage of this cardioplegia is that a single antegrade shot can maintain adequate myocardial protection up to 2 hours; thus, potentially aortic cross-clamp time and cardiopulmonary bypass time can be reduced.

#### **2.6 Unilateral pulmonary edema**

Unilateral pulmonary edema is known as an uncommon, but frequently lethal complication following minimally invasive robotic cardiac surgery. The clinical presentation of this condition includes severe right lung edema developing within the first several minutes to hours after coming off from a cardiopulmonary bypass (**Figure 3**), which leads to profound hypoxia, hypercapnia, pulmonary hypertension, and hemodynamic instability.

The mechanism of this condition is yet to be fully understood. Lung deflation is shown to be associated with the sequestration of inflammatory response. Minamiya et al. reported that during atelectasis, polymorphonuclear leukocytes accumulate in

**Figure 3.** *A typical chest X-ray imaging showing unilateral pulmonary edema on the right side.*

the lung, and after pulmonary reexpansion, polymorphonuclear leukocytes respiratory bursting occurs [24]. The inflammatory response may be aggravated by the use of cardiopulmonary bypass. It is reported that prolonged cardiopulmonary bypass time and lung collapse are associated with the occurrence of unilateral pulmonary edema. Other factors such as obesity and intraoperative blood product use may affect the inflammatory response.

Renner et al. reviewed their 256 patients who underwent minimally invasive mitral valve surgery, and they encountered five cases (2.0%) of unilateral pulmonary edema, which required postoperative extracorporeal membrane oxygenation; two of them had in-hospital mortality [25]. They reported that preoperative high C-reactive protein and long cardiopulmonary bypass time were associated with the occurrence of unilateral pulmonary edema.

Irisawa et al. reviewed 381 patients who underwent minimally invasive cardiac surgery, and found 8 (2.1%) patients developed unilateral pulmonary edema [26]. They reported that preoperative use of steroid or immunosuppressive drugs and prolonged aortic cross-clamp time were the risk factors for unilateral pulmonary edema.

Keyl et al. reported that the use of dexamethasone significantly reduced the incidence of unilateral pulmonary edema from 12.9 to 4.0% [27]. Moss et al. reported their modifications to the robotic mitral valve repair technique in an effort to reduce the incidence of unilateral pulmonary edema [28]. They hypothesized that unilateral pulmonary edema results from severe right lung ischemia due to insufficient bronchial artery flow. Their modifications were focused on right lung oxygen supply, and included minimization of right rung deflation before cardiopulmonary bypass, infusion of unheated CO2 into the right chest, active cooling to low systemic temperature, maintaining high mean arterial pressure during cardiopulmonary bypass, and restoration of right lung ventilation was early as possible.
