Minimal access coronary revascularisation without cardiopulmonary bypass—the impact of robotic technology in the current clinical practice

The midterm outcome and MACE of robotically enhanced grafting of left anterior descending artery with left internal mammary artery

BACKGROUND

We assessed the midterm outcome and the incidence of major adverse cardiovascular events in UK's largest Da Vinci assisted robotic coronary revascularisation cohort. This study was set up at the Imperial College NHS Trust, St. Mary's Hospital, London, United Kingdom.

METHOD

Benchmarking approach through retrospective audit of the regional outcomes against standards in the published literature. Data was collected from the patient's records, communication with the primary care physicians and the national strategic tracing service. The results were compared with the published literature. Patients who underwent robotic assisted coronary revascularisation were included. Other robotic procedures or minimally invasive revascularisation without the use of the Da Vinci robot were excluded. The main outcome measure was the midterm survival up to five years and the incidence of major adverse cardiovascular events (MACE) up to three years.

RESULTS

Since April 2002, one hundred consecutive patients underwent either off pump robotic assisted single vessel small thoracotomy (SVST, n=88), or off pump total endoscopic coronary artery bypass grafting (TCAB, n=12). All patients were operated on by the same primary surgeon but different assisting surgeons. All patients received a left internal mammary arterial (LIMA) graft as planned. The primary outcome of total one month and three years MACE and up to five year survival was 0, 9 and 96% respectively.

CONCLUSIONS

The procedural success rates in terms of morbidity and mortality up to five years are compatible to the outcomes observed outside the United Kingdom. These results are not inferior to that of conventional off pump single vessel coronary surgery or percutaneous coronary intervention to the LAD.

Synchronization of epicardial crawling robot with heartbeat and respiration for improved safety and efficiency of locomotion

BACKGROUND

HeartLander is a miniature mobile robot designed to navigate over the epicardium of the beating heart for minimally invasive therapy. This paper presents a technique to decrease slippage and improve locomotion efficiency by synchronizing the locomotion with the intrapericardial pressure variations of the respiration and heartbeat cycles.

METHODS

Respiratory and heartbeat phases were detected in real time using a chest-mounted accelerometer during locomotion in a porcine model in vivo. Trials were conducted over the lateral aspect of the heart surface to test synchronized locomotion against an unsynchronized control.

RESULTS

Offline evaluation showed that the respiration and heartbeat algorithms had accuracies of 100% and 88%, respectively. Synchronized trials exhibited significantly lower friction, higher efficiency, and greater total distance traveled than control trials.

CONCLUSION

Synchronization of the locomotion of HeartLander with respiration and heartbeat is feasible and results in safer and more efficient travel on the beating heart.

Robotically assisted atraumatic coronary artery bypass: a feasible option for off-pump coronary surgery

This retrospective study of the largest single center experience (100 patients) with off-pump robotically assisted coronary procedures in the United Kingdom (April 2002-June 2008) aimed to rationalize patient selection, describe the technique, and determine the learning curve, technical feasibility and operative outcome of robotically assisted Atraumatic Coronary Artery Bypass (ACAB). Selected patients underwent either a robotic Totally Endoscopic Coronary Artery Bypass (12) or robotically assisted ACAB (88) using a standard Da Vinci robot with three arms. A fifth of all cases had percutaneous interventions as part of a hybrid strategy. The majority of patients were overweight men. After one hundred robotic coronary procedures, this operation is now performed as part of a routine theatre list. The mean operative and total procedure times for robotically assisted atraumatic procedures were 157 and 238 min, respectively. These measurements were significantly less in the atraumatic than the totally endoscopic group with a 34.3 and 20.6% reduction, respectively (P < 0.001; equal variance not assumed). The procedural learning curve was short and independent from internal thoracic artery harvesting. We have proven conclusively that robotically assisted ACAB is feasible, more so than the totally endoscopic procedure in this particular setting. Even in the absence of an ideal stabilizer device, this procedure causes minimal disruption to the daily operating room schedule. We have also proven that body mass index is a weak predictor of the ease of robotic internal thoracic artery harvesting and should not affect patient selection.

Computer-assisted navigation applied to fetal cardiac intervention

BACKGROUND

Prenatal cardiac interventions (PCI) for human fetal aortic valve (AoV) stenosis can reduce left ventricular hypoplasia and restore ventricular growth and function. However, 'freehand' needle delivery from the maternal skin through the uterine wall, fetal chest and ventricular apex to cross the fetal AoV remains technically challenging and time intensive, and is the rate-limiting step in the procedure.

METHODS

We developed a computer-assisted navigation (CANav) system that tracks the position and orientation of a two-dimensional (2D) ultrasound image relative to the trajectory of an electromagnetic (EM) embedded needle and stylet. We tested the CANav system in vitro using a water bath phantom, then in vivo using adult rats and pregnant (fetal) sheep.

RESULTS

The CANav system accurately tracked the delivered needle position in both in vitro phantom and adult rat model experiments. We performed 22 PCI attempts with or without CANav in a fetal sheep model. Maternal laparotomy was required to adjust the fetal position in 50% of the procedures. The time required to deliver the needle from the skin into the left ventricle (LV) using CANav was 2.9 +/- 1.7 (range 2-7) min (n = 14) vs. 5.5 +/- 4.3 (range 1-12) min (n = 8) without CANav (p < 0.05). The time needed to cross the aortic valve once the needle was within the LV was similar with and without CANav (p = 0.19).

CONCLUSIONS

CANav reduces the PCI time required to accurately deliver a needle to the fetal heart. Adaptations of this technical approach may be relevant to other congenital cardiac conditions and ultrasound-guided medical procedures.