Minimally Invasive Cardiac Surgery Research Articles

Emergence of a new direction in our specialty: catheter-assisted cardiac surgery

Emergence of a new direction in our specialty: catheter-assisted cardiac surgery

Vacuum assisted cardiopulmonary bypass in minimally invasive cardiac surgery: its feasibility and effects on hemolysis.

The present study describes a cardiopulmonary bypass (CPB) technique that incorporates vacuum assisted venous drainage and arterial return using a centrifugal pump in minimally invasive cardiac surgery (MICS). The technique was performed on 40 patients scheduled to undergo MICS. The proposed CPB technique enables a good operative field to be obtained even through a limited incision through the use of peripheral cannulation using small cannulae. Vacuum pressure was applied to the venous reservoir (-43 +/- 14 mm Hg) to maintain adequate CPB flow (>2.4 L x min-1 x M-2). The effects of CPB on hemolysis were subsequently compared between patients who underwent the proposed procedure (MICS group; n = 6) and a control group who underwent coronary arterial bypass grafting (CABG group; n = 6) with conventional CPB. Plasma free hemoglobin (FHb) increased and plasma haptoglobin (Hp) decreased during CPB in both groups, with no significant difference between the groups. By the next day, FHb had returned to pre-CPB levels whereas Hp remained lower in both groups. Again, these values did not differ significantly between groups. Thus, we conclude that the proposed CPB technique is useful in MICS with acceptable effects on hemolysis.

Development of a completely closed circuit using an air filter in a drainage circuit for minimally invasive cardiac surgery.

The completely closed circuit system is the future direction of cardiopulmonary bypass because of its compactness and superior biocompatibility. The most serious obstacle for clinical application is the sucking of air bubbles into the drainage circuit. The purpose of this study was to remove the air bubbles from the drainage circuit. Infusing 50 ml/min of air bubbles into the drainage circuit of the usual closed circuit, and infusing 50, 100, and 150 ml/min of air into the drainage circuit of a newly developed closed circuit (drainage circuit using an air filter), the number and size of air bubbles were observed at the outlet of the arterial filter. In the usual closed circuit, many air bubbles of over 40 microm were detected within 5 s at a blood flow of 4 L/min because the centrifugal pump decreased the size of the bubbles, which then passed through the oxygenator and arterial filter. Air bubbles of over 40 micro were not detected in the newly developed closed circuit within 5 min at a blood flow of 4 L/min. The removal of air mixed into the completely closed circuit was possible with a drainage circuit using an air filter that was developed. The clinical use of the completely closed circuit for minimally invasive cardiac surgery (MICS) became possible based on this development.

USE OF A NEW VENOUS CANNULA FOR MINIMALLY INVASIVE CARDIAC SURGERY

Interest in minimally invasive cardiac surgery (MICS) for cardiac disease continues to increase because it causes less surgical trauma and produces a better cosmetic appearance. We introduced the transxiphoid approach without sternotomy for the correction of congenital heart defects. To improve exposure of the cardiac lesion during MICS, we developed a new venous cannula. The new venous cannula is made of wire-reinforced silicone, with an inflatable balloon attached at tip of the cannula. The advantages of this cannula are its extremely flexibility and the fact that a tape does not need to be placed around the vena cava. During a period of 10 months, seven children (3 boys and 4 girls) whose ages ranged from 2 years to 9 years (mean age, 4 years) underwent closure of atrial septal defects. The approach consisted of a 4 to 5 cm low midline incision with division of the xiphoid only with bicaval cannulation and arterial cannulation through the incision. The new venous cannula was used as the SVC cannula. It is not necessary to place a tape around the superior vena cava when using the new venous cannula. All the patients survived the operation. This new venous cannula provided better exposure during cardiac surgery through a limited incision and is beneficial for minimally invasive cardiac surgery.

Experience with a new OR dedicated to robotic surgery

SummaryThe use of robotic technology for minimally-invasive cardiac surgery requires a new operating room (OR) environment. Remote surgery is performed by isolating the surgeon in a central control-room, while the surgical manipulator is located in the OR. Due to the complex nature of these new procedures and the limited access that, unlike in open cardiac surgery, no longer allows direct visualisation of the heart, extensive intra-operative monitoring is essential. The OR features an angiography unit that allows multidisciplinary procedures to be carried out in close collaboration with interventional cardiologists.

ENDOSTAB: An Endoscopic Pressure Stabiliser for Minimally-Invasive Cardiac Surgery using Specially Etched Superelastic NiTi Wires for Joint-like Behaviour

For a long time, the only way to access the heart for a bypass operation was to sever the sternum (median sternotomy). Encouraged by the successes achieved by minimally-invasive surgery in other fields, cardiosurgery underwent rapid development, which eventually enabled thoracoscopic operations of the heart. Only with the development of complex robot systems and telesurgery, however, did it become possible to perform exclusively endoscopic bypass operations. Today, the heart-lung machine (HLM) is used as a standard device for bypass operations, with cardiac arrest induced by an infusion. Studies have shown that the HLM may lead to a significant inflammatory reaction and that it is advantageous, particularly for patients with bad cardiac function, to avoid cardiac arrest and keep the heart continuously supplied with blood. ‘Stabilisers’ have been developed to enable bypass operations on the beating heart without using an HLM. For operations on the beating heart using an exclusively endoscopic robot system, an endoscopic stabiliser has been developed, in cooperation with the Leipzig Cardiovascular Institute. The stabilisers that are already available are rigid and, hence, only suitable for an ‘open’ intervention, in conjunction with a retractor. Based on a flexible, superelastic unit made of NiTi, a stabiliser has now been developed that allows endoscopic insertion via a tube of 10 mm in diameter. Joint-like behaviour is achieved by the shaping of the NiTi wires and the specific removal of material in the curved areas. In the operating state, the stabiliser IS still rigid enough to immobilise the desired vascular section. The ENDOSTAB endoscopic stabiliser has already been successfully used in animal experiments at the Leipzig Cardiovascular Institute. The way is thus paved for exclusively endoscopic bypass operations on the beating heart without the use of an HLM.

Introduction

Introduction

Minimally Invasive Cardiac Surgery.

Minimally invasive techniques have recently been introduced into cardiac surgical procedures. Opportunities to make coronary artery bypass less invasive include elimination or minimization of both incisions and cardiopulmonary bypass. The current spectrum of minimally invasive coronary bypass procedures range from the minimally invasive direct vision coronary artery bypass procedure, which eliminates both the sternotomy incision and cardiopulmonary bypass, to the port access approach, which uses femoral-femoral bypass. Current procedures are also being used to make mitral and aortic valve surgery as well as saphenous vein harvest less invasive.

Cardiology. Minimally invasive cardiac surgery (MICS).

Minimally invasive cardiac surgery (MICS) has been described by some surgeons as a quantum leap forward which could soon replace some forms of traditional surgery. Sally Glennen and Helen Metcalfe describe the procedure and nursing care involved.