Use of BITAs in CABG has shown improved survival and increased freedom from reintervention.1 Total arterial revascularization with composite arterial grafts has clearly improved the midterm and long-term outcomes.2 However, the use of BITAs has not been optimal in CABG because of increased incidence of sternal complications especially in patients with diabetes.
The approach for minimal access coronary bypass surgery has been an anterior approach for grafting of the left anterior descending artery with a pedicled ITA conduit.3 Calafiore and colleagues4 popularized minimally invasive CABG through a small left anterior thoracotomy and reported the largest series, extending the indication to patients with multivessel coronary disease. McGinn et al5 have shown that in MICS CABG, applicability, revascularization completeness, morbidity profile, and safety were excellent and were maintained despite rapid procedural adoption. However, there was no use of BITAs harvested under direct vision via a left minthoracotomy.
Harvesting of ITAs with conventional thoracoscopic instruments with video assist has been limited because of lack of precision, instrument factors, and limitations.3 The introduction of robots has added to the total endoscopic harvest of the ITAs; however, the limitations have been the cost factor, availability, and steep learning curve.6
Subramanian and colleagues3 reported BITA harvesting with robotic assistance and minimal access multivessel coronary artery bypass. Robotic assistance greatly enhances visualization and thereby results in harvesting longer lengths of conduits, which is essential for multivessel grafting.7,8 In our study, for enhanced visualization of the lower thirds of the RITA and the LITA and also in increasing the space required for manipulation of the heart, a 0.5-in subxiphoid incision was made through which a langenbeck retractor was insinuated on the undersurface of the sternum and traction was given using a Rultract ITA retractor. This elevated the undersurface of the sternum and enabled us not only to manipulate with ease the minimal access instruments within the thorax but also to visualize the distal ends of both the RITA and the LITA. This resulted in our ability to harvest conduits of more than adequate length for complete arterial revascularization. This incision was later used to insert a pleural drain. Further, avoiding a median sternotomy, BITAs were used without increasing the risk for wound dehiscence, noting particularly the large number of patients with diabetes in our study group.
Multivessel coronary artery bypass through minimal access has been performed using peripheral arterial cannulation and cardioplegic arrest.9,10 Our technique encompassed a method in which through a 2-in left minithoracotomy, BITAs of adequate length were conveniently harvested in a skeletonized manner under direct vision. Total arterial off-pump complete myocardial revascularization was then done using the LITA-RITA Y composite conduit. This grossly reduced the invasiveness when compared with CABG through a sternotomy.
Vassiliades11 has described port-access stabilization in endoscopic coronary artery bypass for LITA to left anterior descending artery anastomoses. In our study, we have used the Acrobat Suv coronary artery stabilizer for positioning and stabilization of all coronary targets. The use of intraoperative transesophageal echocardiography while positioning for the various grafts preempted any hemodynamic instability.
The postoperative recovery was good, with most of the patients being extubated on the OR table. Operating times were comparable with standard CABG, and postoperative pain was well controlled with paravertebral block using continuous sensoricaine infusion for 24 hours. The hospital stay was minimal, with the mean hospital stay being 3.1 days. This compares favorably with other studies.3 Financial benefits for both the patient and the hospital were also observed. The early outcomes have been good, and coronary angiograms carried out showed widely patent grafts. A limitation of this study has been the absence of postoperative coronary angiograms at 12 months and late graft patency data. However, we have used markers such as stress test, freedom from death, cardiac-related events, and reintervention for graft patency. None of the patients have had any reintervention.
Diegeler et al12 have shown minimally invasive direct coronary artery bypass grafting to be a safe procedure and have also shown this in patients with multiple-vessel coronary artery disease and for patients with severely reduced left ventricular (LV) function. In our study, we have shown the safety of the technique as demonstrated by the low incidence of perioperative and postoperative complications including morbidity. Potential contraindications to this technique are severe chronic obstructive pulmonary disease, PO2 of less than 60 on room air arterial blood gas moderate to severe renal dysfunction, recent myocardial infarction or cerebrovascular accident, and multivessel CABG in hearts with poor ejection fraction (<25%).
We carried out the first 40 cases on the patients with good LV function. As our experience with this technique increased, we started carrying out coronary artery bypass on the patients with lower ejection fractions and finally on the patients with very poor LV function (<20%) having multivessel disease without other targets to bypass than the left anterior descending artery. This technique, we feel, is reproducible; requires the same infrastructure for formal coronary bypass surgery, with the exception being the acquisition of minimally invasive cardiac surgical instrumentation; and can be done on an empty beating heart to aid in training.
In conclusion, we feel that this novel technique will help optimize MICS and the use of BITAs with its associated benefits, without the invasiveness and related complications of a median sternotomy, especially in patients with diabetes. Further, this may allay patient fears of heart surgery and also has the potential for decreased patient morbidity, shorter hospital stay, early return to active life, financial benefits, and good cosmesis (Fig. 8).
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This case series of 150 patients describes a technique to perform off-pump minimally invasive multi-vessel coronary artery bypass grafting using bilateral internal mammary arteries through a small left mini-thoracotomy incision. The mammary arteries were harvested under direct vision without robotic or thoracoscopic assistance. There was one mortality and the average hospital stay was just over three days. There was only one elective conversion to sternotomy. Coronary angiography was done in 37 patients and there were no graft occlusions.
This is an interesting approach which can be done with conventional instrumentation. Early outcomes were very good. The weakness of the study was the absence of graft assessment in the majority of patients. There also was no intraoperative assessment with flow probes. Finally, this represents a single-surgeon experience and it is unclear whether this technique is either widely applicable or reproducible. Future confirmatory studies from other groups will be needed to judge the clinical utility of this technique.
Keywords:©2013 by the International Society for Minimally Invasive Cardiothoracic Surgery
Minimally invasive; Coronary bypass; Bilateral internal thoracic arteries; Left minithoracotomy