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In the adult cardiac surgery audit conducted in 2006, we continued to perform well with an overall mortality of 2.78% for patients undergoing isolated CABG and no mortality for patients undergoing isolated valve procedures. The risk stratified mortalities observed were 0.75% for low risk (predicted risk - 1.7%), 0.53% for the moderate risk (predicted risk - 4.15%) and 9.03% (predicted risk - 13.86%) under the logistic Euroscore Cardiac Risk Factor evaluation analysis.
We conducted a TransMyocardial Laser Revascularisation workshop in 2007 with Dr. Robert Philips from McLeod Regional Medical Centre, South Carolina, USA using a new Holmium YAG laser TMR machine. There have been some recent promising results of TMR treatment for patients with diffuse coronary artery disease using this new TMR machine and we are also evaluating its potential applications in our patient population. We also conducted a Harmonic scalpel workshop in June 2007 with Associate Professor Kieta Kikuchi from Juntendo University School of Medicine, Tokyo with demonstrations on using the harmonic scalpel which uses mechanical energy to harvest skeletonised arterial (left internal mammary artery, radial artery, gastroepiploic artery) conduits for use in CABG instead of standard electrodiathermy. Figure 1
We initiated a Robot Assisted Minimally Invasive Cardiac Surgery (RAMICS) programme in 2006 using the funding from SingHealth Foundation. We have been using a da Vinci robotic system consisting of an ergonomic surgeon’s console, patient-side cart with four nteractive robotic arms, binocular vision system and multi-joint endo-wrist instruments (figure1).
Our first robotic surgery case was an excision of thoracic tumour in 2005. In 2007, we performed 10 robotic-assisted cardiac cases and one robotic-assisted thoracic case. The cardiac cases were four mitral valve repairs, one atrial septal defect (ASD) repair, four robotic-assisted left internal mammary artery (LIMA) harvest. All the patients had surgery performed using minimally invasive incisions except for one patient who had a sternotomy for conventional coronary artery bypass graft surgery after robotic harvest of the LIMA. We hope that this field of minimally invasive cardiac surgery will continue to progress as most of the patients are able to ambulate and get discharged sooner.
We have embarked on an Endovein Harvesting Programme since 2005 with good results. Endoscopic harvest of the saphenous vein is performed using a vein dissector with CO2 insufflation and using bipolar diathermy to divide the side branches. The procedure is especially useful for patients expected to have poor lower limb wound healing ie. obese patients, patients with peripheral arterial disease and diabetic patients. It reduces the leg graft site infections to almost zero and patients who have had it performed are extremely satisfied as they are able to ambulate early with minimal discomfort. The incision is limited to a 1-inch incision around the knee and 1 or 2 stab incisions depending on the length of vein required. We performed 77 endoscopic vein harvests in 2007.
The mid-term 5-year results of the MAZE procedure was presented in 2006 in the winter ISMICS (International Society for Minimally Invasive Cardiothoracic Surgery) conference. The Maze procedure is a surgical procedure designed to create lesions in the atrium so that the mechanisms for the maintenance of chronic atrial fibrillation is interrupted. This procedure is usually performed in conjunction with mitral valve procedures or can also be performed for lone AF. Freedom from atrial fibrillation in the 137 patients who underwent the procedure was (80%) at 5-year post procedure. We were also the first centre in Asia to use the EPICOR cardiac ablation system which uses High Intensity Focused Ultrasound (HIFU) as an energy source to isolate the pulmonary veins. This is an alternative method of treating atrial fibrillation which can be performed without stopping the heart or going on cardiopulmonary bypass.
We performed the first apico-aortic conduit implant in Asia for the treatment of aortic stenosis (figure 2). This procedure involves implanting a valve conduit form the left ventricular apex to the descending aorta in patients where the ascending aorta is “hostile” and operating in that area would impart excessive surgical risk to the patient. The patient did well post operatively.
We are in the process of establishing a National Cardiovascular Homograft Bank after having obtained support from the Ministry of Health through its Health Services Development Programme funding. This involves harvesting aortic and pulmonary valves from donors and processing and cryo-preserving these tissues for use as implants. We have historically imported such homografts subject to availability and at great cost for our patients. A local homograft bank would give our patients access to such tissues for use when indicated for example, in patients with of aortic root endocarditis and in patients requiring outflow tract reconstruction.
Figure 2
We extended our Mechanical Heart Assist Programme to acutely ill patients outside SGH. We have organised our service so that we can put a patient from an outside referring hospital on extra corporeal membrane oxygenation (ECMO) support within one hour of activation. In fact, this project won a merit prize in the 2007 SingHealth Clinical Practice Improvement Programme (CPIP) presentation and was the best quality improvement project from NHC.
In 2006, we put four patients on ECMO in the referring hospital(s) and transferred them back for further management. We implanted a Ventricular Assist Device (VAD) in two patients who required a longer period of cardiac support and bridged them to cardiac transplantation and these patients were subsequently discharged well. |