Takeyoshi Ota

Impact of endoscopic versus open saphenous vein harvest technique on late coronary artery bypass grafting patient outcomes in the ROOBY (Randomized On/Off Bypass) Trial

OBJECTIVE In the Randomized On/Off Bypass (ROOBY) Trial, the efficacy of on-pump versus off-pump coronary artery bypass grafting was evaluated. This ROOBY Trial planned subanalysis compared the effects on postbypass patient clinical outcomes and graft patency of endoscopic vein harvesting and open vein harvesting. METHODS From April 2003 to April 2007, the technique used for saphenous vein graft harvesting was recorded in 1471 cases. Of these, 894 patients (341 endoscopic harvest and 553 open harvest) also underwent coronary angiography 1 year after coronary artery bypass grafting. Univariate and multivariable analyses were used to compare patient outcomes in the endoscopic and open groups. RESULTS Preoperative patient characteristics were statistically similar between the endoscopic and open groups. Endoscopic vein harvest was used in 38% of the cases. There were no significant differences in both short-term and 1-year composite outcomes between the endoscopic and open groups. For patients with 1-year catheterization follow-up (n=894), the saphenous vein graft patency rate for the endoscopic group was lower than that in the open harvest group (74.5% vs 85.2%, P<.0001), and the repeat revascularization rate was significantly higher (6.7% vs 3.4%, P<.05). Multivariable regression documented no interaction effect between endoscopic approach and off-pump treatment. CONCLUSIONS In the ROOBY Trial, endoscopic vein harvest was associated with lower 1-year saphenous vein graft patency and higher 1-year revascularization rates, independent of the use of off-pump or on-pump cardiac surgical approach.

A fusion protein of hepatocyte growth factor enhances reconstruction of myocardium in a cardiac patch derived from porcine urinary bladder matrix

OBJECTIVE We sought to promote myocardial repair using urinary bladder matrix incorporated with a fusion protein that combined hepatocyte growth factor and fibronectin collagen-binding domain in a porcine model. Collagen-binding domain acted as an intermediary to promote hepatocyte growth factor binding and enhance hepatocyte growth factor stability within urinary bladder matrix. METHODS Urinary bladder matrix incorporated with collagen-binding domain and hepatocyte growth factor was implanted into the porcine right ventricular wall (F group) to repair a surgically created defect. Untreated urinary bladder matrix patches (U group) and Dacron patches (D group) served as controls (N = 5/group). Electromechanical mapping was performed 60 days after surgery. Linear local shortening was used to assess regional contractility, and electrical activity was recorded. RESULTS Linear local shortening was significantly improved in the F group compared with controls (F: 0.51% +/- 1.57% [P < .05], U: -1.06% +/- 1.84%, D: -2.72% +/- 2.59%), whereas it was inferior to the normal myocardium (13.7% +/- 4.3%; P < .05). Mean electrical activity was 1.49 +/- 0.82 mV in the F group, which was statistically greater than in the control groups (U: 0.93 +/- 0.71 mV; D: 0.30 +/- 0.22 mV; P < .05) and less than the normal myocardium (8.24 +/- 2.49 mV; P < .05). Histologic examination showed predominant alpha-smooth muscle actin positive cells with the F group showing the thickest layer and the D group showing the thinnest layer, with an endocardial endothelial monolayer. Scattered isolated islands of alpha-actinin positive cells were observed only in the F group, but not in the controls, suggesting the presence of cardiomyocytes. CONCLUSION The collagen-binding domain/hepatocyte growth factor/urinary bladder matrix patch demonstrated increased contractility and electrical activity compared with urinary bladder matrix alone or Dacron and facilitated a homogeneous repopulation of host cells. Urinary bladder matrix incorporated with collagen-binding domain and hepatocyte growth factor may contribute to constructive myocardial remodeling.

Percutaneous Intrapericardial Interventions Using a Highly Articulated Robotic Probe

In order to overcome the limitations of currently available assistive technologies for minimally invasive surgery (MIS), we have developed a novel highly articulated robotic probe (HARP) that can exploit its snake-like structure to navigate in a confined anatomical environment while minimally interacting with the environment along its path. We believe that for procedures involving epicardial interventions on the beating heart, cardiac MIS can be effectively realized with the HARP, entering the pericardial cavity through a subxiphoid port, reaching remote intrapericardial locations on the epicardium without causing hemodynamic and electrophysiologic interference and delivering therapeutic interventions under the direct control of the surgeon

A Miniature Mobile Robot for Navigation and Positioning on the Beating Heart

Robotic assistance enhances conventional endoscopy; yet, limitations have hindered its mainstream adoption for cardiac surgery. HeartLander is a miniature mobile robot that addresses several of these limitations by providing precise and stable access over the surface of the beating heart in a less-invasive manner. The robot adheres to the heart and navigates to any desired target in a semiautonomous fashion. The initial therapies considered for HeartLander generally require precise navigation to multiple surface targets for treatment. To balance speed and precision, we decompose any general target acquisition into navigation to the target region followed by fine positioning to each target. In closed-chest, beating-heart animal studies, we demonstrated navigation to targets located around the circumference of the heart, as well as acquisition of target patterns on the anterior and posterior surfaces with an average error of 1.7 mm. The average drift encountered during station-keeping was 0.7 mm. These preclinical results demonstrate the feasibility of precise semiautonomous delivery of therapy to the surface of the beating heart using HeartLander.

Minimally Invasive Epicardial Injections Using a Novel Semiautonomous Robotic Device

Background— We have developed a novel miniature robotic device (HeartLander) that can navigate on the surface of the beating heart through a subxiphoid approach. This study investigates the ability of HeartLander to perform in vivo semiautonomous epicardial injections on the beating heart. Methods and Results— The inchworm-like locomotion of HeartLander is generated using vacuum pressure for prehension of the epicardium and drive wires for actuation. The control system enables semiautonomous target acquisition by combining the joystick input with real-time 3-dimensional localization of the robot provided by an electromagnetic tracking system. In 12 porcine preparations, the device was inserted into the intrapericardial space through a subxiphoid approach. Ventricular epicardial injections of dye were performed with a custom injection system through HeartLander’s working channel. HeartLander successfully navigated to designated targets located around the circumference of the ventricles (mean path length=51±25 mm; mean speed=38±26 mm/min). Injections were successfully accomplished following the precise acquisition of target patterns on the left ventricle (mean injection depth=3.0±0.5 mm). Semiautonomous target acquisition was achieved within 1.0±0.9 mm relative to the reference frame of the tracking system. No fatal arrhythmia or bleeding was noted. There were no histological injuries to the heart due to the robot prehension, locomotion, or injection. Conclusions— In this proof-of-concept study, HeartLander demonstrated semiautonomous, precise, and safe target acquisition and epicardial injection on a beating porcine heart through a subxiphoid approach. This technique may facilitate minimally invasive cardiac cell transplantation or polymer therapy in patients with heart failure.

Improved Traction for a Mobile Robot Traveling on the Heart

This document describes the effects of several design parameters on the traction generated by the suction pads of a mobile robot that walks on the surface of the heart. HeartLander is a miniature mobile robot that adheres to the epicardial surface of the heart using suction, and can travel to any desired location on the heart to administer therapeutic applications. To maximize the effectiveness of locomotion, the gripper pads must provide sufficient traction to avoid slipping. Our testing setup measured the force applied to the gripper pad adhering to ovine epicardial tissue, and recorded overhead video for tracking of the pad and tissue during an extension. By synchronizing the force and video data, we were able to determine the point at which the pad lost traction and slipped during the extension. Of the pads tested, the pad with no suction grate achieved maximum traction. Increasing the extension speed up to 20 mm/s resulted in a corresponding increase in traction. Increasing the vacuum pressure also improved the traction, but the magnitude of the effect was less than the improvement gained from increasing extension speed

Highly articulated robotic probe for minimally invasive surgery

We have developed a novel highly articulated robotic probe (HARP) that can thread through tightly packed volumes without disturbing the surrounding tissues and organs. We use cardiac surgery as the focal application of this work. As such, we have designed the HARP to enter the pericardial cavity through a subxiphoid port. The surgeon can effectively reach remote intrapericardial locations on the epicardium and deliver therapeutic interventions under direct control. Our device differs from others in that we use conventional actuation and still have great maneuverability. We have performed proof-of-concept clinical experiments to give us preliminary validation of the ideas presented here.

Newly Developed Tissue-Engineered Material for Reconstruction of Vascular Wall Without Cell Seeding

BACKGROUND We have developed a tissue-engineered patch for cardiovascular repair. Tissue-engineered patches facilitated site-specific in situ recellularization and required no pretreatment with cell seeding. This study evaluated the patches implanted into canine pulmonary arteries. METHODS Tissue-engineered patches are biodegradable sheets woven with double-layer fibers. The fiber is composed of polyglycolic acid and poly-L-lactic acid, and compounding collagen microsponges. The patches (20- x 25-mm) were implanted into the canine pulmonary arterial trunks. At 1, 2, and 6 months after implantation (n = 4), they were explanted and characterized by histologic and biochemical analyses. Commercially available patches served as the control. No anticoagulant therapy was administered postoperatively. RESULTS No aneurysm or thrombus was present within the patch area in all groups. The remodeled tissue predominantly consisted of elastic and collagen fibers, and the endoluminal surface was covered with a monolayer of endothelial cells and multilayers of smooth muscle cells beneath the endothelial layer. The elastic and collagen fibers and smooth muscle cells kept increasing with a maximum at 6 months, while a monolayer of endothelial cells was preserved. The expression levels of messenger RNA of several growth factors in the tissue-engineered patches were higher than those of native tissue at 1 and 2 months and decreased to normal level at 6 months. No regenerated tissue was found on the endoluminal surface in the control group. CONCLUSIONS The novel tissue-engineered patches showed in situ repopulation of host cells without prior ex vivo cell seeding. This is promising material for repair of the cardiovascular system.

A novel highly articulated robotic surgical system for epicardial ablation

We have developed a novel, highly articulated robotic surgical system to enable minimally invasive intrapericardial interventions through a subxiphoid approach and have performed preliminary tests of epicardial left atrial ablation in porcine (N = 3) and human cadaver (N = 2) preparations. In this study, the novel highly articulated robotic surgical system successfully provided safe epicardial ablations to the left atrium in porcine beating heart models via a subxiphoid approach. We have also performed complex guidance of the robot and subsequent ablation in a cadaveric preparation for successful pulmonary vein isolation.

Left Atrial Wall Hematoma/Dissection After Mitral Valve Replacement

A 63-year-old woman with a significant history of rheumatic mitral stenosis/regurgitation, tricuspid regurgitation, atrial fibrillation, and giant left atrium (LA; 90 mm in diameter) underwent mitral valve replacement with a mechanical valve, tricuspid annuloplasty, and LA appendage closure. The mitral valve was approached by a conventional left atriotomy from the right side of the LA. The postoperative course was uneventful initially, and the patient was extubated on postoperative day 1. On postoperative day 2, however, acute hemodynamic deterioration occurred that required reintubation and a high dose of inotropes. Transthoracic echocardiography showed a large mass in the LA that occupied almost the entire LA cavity (Figure …