2 The procedure
2.1.1 In coronary artery disease, plaque deposits on the inner walls of the coronary arteries lead to narrowing or occlusion, and subsequently decreased oxygen supply to the heart. This may cause angina or myocardial infarction, and long-term weakening of the heart muscle leading to heart failure or arrhythmia.
2.1.2 The aim of a coronary artery bypass graft (CABG) is to increase the flow of blood to the heart by inserting grafts to bypass narrowed or obstructed coronary arteries.
2.1.3 CABG is usually performed with open surgery through a sternotomy. Less invasive approaches avoiding sternotomy, cardiopulmonary bypass and general anaesthesia have been developed, using either left anterior small thoracotomy (LAST), regional anaesthesia or catheter-based intervention.
2.2.1 Totally endoscopic robotically assisted coronary artery bypass (TECAB) systems vary, but they generally include a surgeon's viewing and control console with display system. Remote-control handles control robotic arms that position and precisely manoeuvre an endoscope and endoscopic instruments within the patient. Some equipment uses voice-controlled robotic arms.
2.2.2 Following deflation of the lung, small port incisions are made in three intercostal spaces through which one robotic arm carrying the endoscope and two arms with surgical implement attachments are introduced. Grafts are harvested from suitable donor sites, and are used to bypass one or more diseased coronary arteries.
2.2.3 TECAB treatment of the beating heart is carried out using a stabilisation device consisting of two branches that immobilise the site for anastomosis while the heart continues to beat. This removes the need for cardiopulmonary bypass. The stabilisation device is introduced into the chest through an additional port incision.
2.3.1 Fully patent grafts were achieved in 95% (21/22) of patients when assessed at 3 months by postoperative angiography, together with good functional results.
2.3.2 Most case series used duration of operation as a measure and this varied according to the type of procedure undertaken and the number of vessels bypassed. In 45 consecutive patients undergoing TECAB, the mean operating time was 4 hours 12 minutes for single vessel surgery and 6 hours 18 minutes for multiple vessel surgery. In 35 patients, including eight in whom the procedure was performed on the beating heart, the operating time ranged from 3 hours 30 minutes to 8 hours (mean 5 hours 47 minutes). In a further 37 patients (29 of whom had the beating heart procedure), the mean operating time for the early cases in the series was 4 hours 40 minutes, but this was reduced to 3 hours 6 minutes following the introduction of endoscopic stabilisation. The mean length of stay in an intensive care unit varied from 14 hours to 74 hours, and the mean total length of hospital stay ranged from 5.0 to 15.4 days. The upper limits for length of stay were following multiple vessel surgery. For more details, refer to the Sources of evidence.
2.3.3 The Specialist Advisors noted that bleeding could potentially make vessel identification difficult. They also noted that patency rates of coronary bypass grafts were not sufficiently well documented.
2.4.1 Conversion rates to open procedures (either mini-thoracotomy or full sternotomy) were reported in all case series and ranged from 19% (5/27) to 51% (19/37) of procedures initiated as TECAB.
2.4.2 There were no cases of operative mortality associated with the TECAB procedure (n = 142).
2.4.3 In a case series of 45 patients, operative complications included port access failure in 7% (3/45) of patients, prolonged cross clamp time in 9% (4/45), myocardial infarction in 2% (1/45), hypoxic brain damage in 2% (1/45) and internal thoracic artery injury in 2% (1/45) of patients.
2.4.4 In a series of 45 patients, 4% (2/45) needed secondary intervention because of bleeding from the site of anastomosis. There were no cases of wound infection at the port site throughout the series. For more details, refer to the Sources of evidence.
2.4.5 The Specialist Advisors noted theoretical complications as myocardial infarction, pneumothorax, cardiac tamponade and fatal haemorrhage. They also noted that there is potential for stenosis or occlusion at the site of anastomosis.