Coronary artery bypass grafting without cardiopulmonary bypass and without interruption of native coronary flow using a novel anastomosis site restraining device ("Octopus")

Thirteen Years of Impactful, Minimally Invasive Coronary Surgery: Short- and Long-Term Results for Single and Multi-Vessel Disease

OBJECTIVES

Minimally invasive coronary surgery (MICS) via lateral thoracotomy is a less invasive alternative to the traditional median full sternotomy approach for coronary surgery. This study investigates its effectiveness for short- and long-term revascularization in cases of single and multi-vessel diseases.

METHODS

A thorough examination was performed on the databases of two cardiac surgery programs, focusing on patients who underwent minimally invasive coronary bypass grafting procedures between 2010 and 2023. The study involved patients who underwent either minimally invasive direct coronary artery bypass grafting (MIDCAB) for the revascularization of left anterior descending (LAD) artery stenosis or minimally invasive multi-vessel coronary artery bypass grafting (MICSCABG). Our assessment criteria included in-hospital mortality, long-term mortality, and freedom from reoperations due to failed aortocoronary bypass grafts post-surgery. Additionally, we evaluated significant in-hospital complications as secondary endpoints.

RESULTS

A total of 315 consecutive patients were identified between 2010 and 2023 (MIDCAB 271 vs. MICSCABG 44). Conversion to median sternotomy (MS) occurred in eight patients (2.5%). The 30-day all-cause mortality was 1.3% (n = 4). Postoperative AF was the most common complication postoperatively (n = 26, 8.5%). Five patients were reoperated for bleeding (1.6%), and myocardial infarction (MI) happened in four patients (1.3%). The mean follow-up time was six years (±4 years). All-cause mortality was 10.3% (n = 30), with only five (1.7%) patients having a confirmed cardiac cause. The reoperation rate due to graft failure or the progression of aortocoronary disease was 1.4% (n = 4).

CONCLUSIONS

Despite the complexity of the MICS approach, the results of our study support the safety and effectiveness of this procedure with low rates of mortality, morbidity, and conversion for both single and multi-vessel bypass surgeries. These results underscore further the necessity to implement such programs to benefit patients.

Anesthesia management of patients undergoing off-pump coronary artery bypass grafting: A retrospective study of single center

Background

To summarize the current practice of anesthesia management for Chinese patients undergoing off-pump coronary artery bypass (OPCAB) surgery at a large-volume cardiovascular center.

Materials and methods

The clinical data of consecutive patients undergoing isolated, primary OPCAB surgery during the period from September 2019 to December 2019 were retrospectively analyzed. Patient characteristics, intraoperative data, and short-term outcomes were extracted from the Hospital Information System and the Anesthesia Information Management System.

Results

A total of 255 patients who underwent OPCAB surgery were enrolled in the current study. High-dose opioids and short-acting sedatives were the most commonly administrated anesthetics intraoperatively. Pulmonary arterial catheter insertion is frequently performed in patients with serious coronary heart disease. Goal-directed fluid therapy, a restricted transfusion strategy, and perioperative blood management were routinely used. Rational usages of inotropic and vasoactive agents facilitate hemodynamic stability during the coronary anastomosis procedure. Four patients underwent re-exploration for bleeding, but no death was observed.

Conclusions

The study introduced the current practice of anesthesia management at the large-volume cardiovascular center, and the short-term outcomes indicated the efficacy and safety of the practice in OPCAB surgery.

Historical evolution of robot-assisted cardiac surgery: a 25-year journey

Many patients and surgeons today favor the least invasive access to an operative site. The adoption of robot-assisted cardiac surgery has been slow, but now has come to fruition. The development of modern surgical robots took surgeons close collaboration with mechanical, electrical, and optical engineers. Moreover, the necessary project funding required entrepreneurs, federal grants, and venture capital. Non-robotic minimally invasive cardiac surgery paved the way to the application of surgical robots by making changes in operative approaches, instruments, visioning modalities, cardiopulmonary perfusion techniques, and especially surgeons' attitudes. In this article, the serial development of robot-assisted cardiac surgery is detailed from the beginning and through clinical application. Included are references to the historical and most recent clinical series that have given us the evidence that robot-assisted cardiac surgery is safe and provides excellent outcomes. To this end, in many institutions these procedures now have become a new standard of care. This evolution reflects Sir Isaac Newton's famous 1676 quote when referring to Rene Descartes, "If have seen further [sic] than others, it is by standing on the shoulders of giants".

Preclinical Comparison of Distal Off-Pump Anastomotic Remodeling: Hand-Sewn Versus ELANA Heart Bypass

Objective: The ELANA Heart Bypass System is a new sutureless technique for coronary anastomoses. A titanium clip connects the graft with the coronary artery, whereafter the arteriotomy is performed by excimer laser. Since this anastomotic construction evidently differs from the standard hand-sewn anastomosis, we aim to evaluate the process of anastomotic healing and remodeling. Methods: Preclinical evaluation of anastomotic remodeling in 42 pigs who underwent off-pump left internal mammary artery to left anterior descending artery anastomosis by either the ELANA Heart Bypass (n = 24) or the hand-sewn (n = 18) technique. Anastomotic remodeling was evaluated by scanning electron microscopy and histology in short-term follow-up intervals up to 3 months. Anastomotic patency is determined by coronary angiography at latest follow-up before termination. Results: The nonendothelial surface of both the ELANA and the hand-sewn anastomoses were covered with neointima from 14 days onwards. Only half the amount of intima hyperplasia was present in the anastomotic surface of the patent ELANA anastomosis, compared with the hand-sewn anastomosis (98 [48–1358] vs 218 [108–296] µm, P = 0.001). Yet patency of the ELANA was inferior to the hand-sewn anastomoses (79% vs 100%, P = 0.06). Conclusions: This study shows the technical perioperative feasibility of the ELANA Heart Bypass System. Although limited intima hyperplasia was observed, hand-sewn anastomoses had superior patency during follow-up. The results of this trial suggest that an additional study with a new prototype is required before clinical implementation.

Influence of Internal Thoracic Artery Harvesting on Sternal Osteoblastic Activity and Perfusion

The purpose of this study was to assess the sternal osteoblastic activity and perfusion in the early period after a coronary artery bypass graft (CABG) using single-photon emission computed tomography (SPECT) and three-phasic dynamic scintigraphy (3PDS) with 99mTc methylene diphosphonate (MDP).

METHODS

The study group consisted of 57 male patients that were 57.3 ± 6.6 years of age. Thirty-six of them were randomized into two groups: in group I (n = 18), the internal thoracic artery (ITA) was skeletonized, and in group II (n = 18), the ITA was pedicled. All the patients in groups I and II underwent an off-pump CABG using 1.7 ± 0.3 grafts, including one anastomosis of the ITA to the left anterior descending coronary artery. The control group III (n = 21) consisted of patients that underwent mitral valve repair surgery, in whom the sternotomy without the ITA harvesting was performed. The 3PDS and SPECT of the thorax with 99mTc MDP were performed 2 weeks after surgery.

RESULTS

The sternal phosphates uptake in group I was approximately twice as high as in group II and approximately 1.5 times higher than in group III (p < 0.05). The MDP uptake asymmetry after the ITA skeletonization was the same as in the group with both intact ITAs. In contrast, after the pedicled ITA harvesting, the osteoblastic activity of the ipsilateral side of the sternum was lower than in the contralateral one. There was no statistically significant difference in scintillation count in the xiphoid process between groups I and II (p > 0.05); however, we observed a significant difference in the manubrium and body (p < 0.05).

CONCLUSION

The main factor that improved the sternal perfusion after a CABG was the preservation of branches supplying the sternum using the skeletonization technique of ITA harvesting.

Effect of octopus tissue stabilizer on cardiac output during off-pump coronary artery bypass graft surgery

Introduction

Significant hemodynamic derangements can occur during off-pump coronary artery bypass graft (OPCAB) surgery resulting from the displacement of the beating heart, which may necessitate conversion to on-pump surgery.

Aim

We proposed to evaluate the alterations in hemodynamic parameters in patients during the course of anastomosis in OPCAB surgery using the Octopus tissue stabilizer.

Material and methods

In 100 consecutive patients undergoing OPCAB surgery, hemodynamic variables including cardiac output (CO), heart rate (HR), mean arterial pressure (MAP) and central venous pressure (CVP) were recorded at baseline, during each coronary artery anastomosis at 2 min, 10 min and after release of the Octopus tissue stabilizer.

Results

CO decreased significantly after target stabilization and during all coronary anastomoses (5.42 ±1.1 l/min at baseline, 4.26 ±1.02 l/min at 2 min and 3.92 ±0.98 l/min at 10 min; p < 0.001), with the greatest decrease noted during obtuse marginal (OM) branch of left circumflex artery anastomosis (3.67 ±0.86 l/min at 2 min and 3.38 ±0.78 l/min at 10 min). Inotropic drugs were required to maintain mean arterial pressure (MAP) > 60 mm Hg in 43 patients, which was most frequently noted during OM anastomosis (p < 0.001). The incidence of bradycardia requiring inotropes was noted to be the highest during left anterior descending (LAD) artery anastomosis (p = 0.002).

Conclusions

During OPCAB surgery using the Octopus for coronary target stabilization, CO decreased the most during OM anastomosis requiring inotropes, while bradycardia was most frequent during LAD anastomosis. Careful monitoring and management of hemodynamic variables are therefore of utmost importance to avoid conversion to on-pump surgery.

Ten-Year Follow-Up of Off-Pump and On-Pump Multivessel Coronary Artery Bypass Grafting: MASS III

It was a randomized trial, and 308 patients undergoing revascularization were randomly assigned: 155 to off-pump coronary artery bypass (OPCAB) and 153 to on-pump coronary artery bypass (ONCAB). End points were freedom from death, myocardial infarction, revascularization, and cerebrovascular accidents. The rates for 10-year, event-free survival for ONCAB versus OPCAB were 69.6% and 64%, (hazard ratio [HR]: 0.88; 95% confidence interval [CI] 0.86-1.02; P = .41), respectively. Adjusted Cox proportional hazard ratio was similar (HR: 0.92; 95% CI 0.61-1.38, P = .68). A difference occurred between the duration of OPCAB and ONCAB, respectively (4.9 ± 1.5 vs 6.6 ± 1.1 h, P < .001). Statistical differences occurred between OPCAB and ONCAB in the length of intensive care unit (ICU) stay (20 ± 2.5 vs 48 ± 10 hours, P < .001), time to extubation (5.5 ± 4.2 vs 10.2 ± 3.5 hours, P < .001), hospital stay (6.7 ± 1.4 vs 9.2 ± 1.3 days, P < .001), higher incidence of atrial fibrillation (AF; 33 vs 5 patients, P < .001), and blood requirements (46 vs 64 patients, P < .001). Grafts per patient was higher in ONCAB (3.15 vs 2.55 grafts, P < .001). No difference existed between the groups in primary composite end points at 10-year follow-up. Although OPCAB surgery was related to a lower number of grafts and higher incidence of AF, it had no effects related to long-term outcomes.

Risk Factors of On-Pump Conversion during Off-Pump Coronary Artery Bypass Graft

Background

Off-pump coronary artery bypass grafting (OPCABG) procedures can avoid the complications of an on-pump bypass. However, some cases unexpectedly require conversion to cardiopulmonary bypass during OPCABG. The risk factors associated with a sudden need for cardiopulmonary bypass were analyzed.

Methods

This retrospective study included 283 subjects scheduled for OPCABG from 2001 to 2010. These were divided into an OPCABG group and an on-pump conversion group. Preoperative, operative, and postoperative variables were compared between the 2 groups.

Results

Of the 283 patients scheduled for OPCABG, 47 (16%) were switched to on-pump coronary artery bypass grafting (CABG). The mortality of the both the OPCABG and on-pump conversion groups was not significantly different. The major risk factors for conversion to on-pump CABG were congestive heart failure (CHF) (odds ratio [OR], 3.5; p=0.029), ejection fraction (EF) <35% (OR, 4.4; p=0.012), and preoperative beta-blocker (BB) administration (OR, 0.3; p=0.007). The use of intraoperative (p=0.007) and postoperative (p=0.021) inotropics was significantly higher in the conversion group. The amount of postoperative drainage (p<0.001) and transfusion (p<0.001) also was significantly higher in the conversion group. There were no significant differences in stroke or cardiovascular complications between the groups over the course of short-term and long-term follow-up.

Conclusion

Patients who undergo OPCABG and have CHF or a lower EF (<35%) are more likely to undergo on-pump conversion, while preoperative BB administration could help prevent conversions from OPCABG to on-pump CABG.

Significant elevation of biomarkers of myocardial necrosis after coronary artery bypass grafting without myocardial infarction established assessed by cardiac magnetic resonance

The release of myocardial necrosis biomarkers after off-pump coronary artery bypass grafting (OPCAB) frequently occurs. However, the correlation between biomarker release and the diagnosis of procedure-related myocardial infarction (MI) (type 5) has been controversial. This study aimed to evaluate the amount and pattern of cardiac biomarker release after elective OPCAB in patients without evidence of a new MI on cardiac magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE).Patients with normal baseline cardiac biomarkers referred for elective OPCAB were prospectively included. CMR with LGE was performed in all patients before and after interventions. Measurements of troponin I (cTnI) and creatine kinase MB fraction (CK-MB) were systematically performed before and after the procedure. Patients with new LGE on the postprocedure CMR were excluded.All of the 53 patients without CMR evidence of a procedure-related MI after OPCAB exhibited a cTnI elevation peak above the 99th percentile. In 48 (91%), the peak value was >10 times this threshold. However, 41 (77%) had a CK-MB peak above the limit of the 99th percentile, and this peak was >10 times the 99th percentile in only 7 patients (13%). The median peak release of cTnI was 0.290 (0.8-3.7) ng/mL, which is 50-fold higher than the 99th percentile.In contrast with CK-MB, considerable cTnI release often occurs after an elective OPCAB procedure, despite the absence of new LGE on CMR.

Suction catheter for enhanced control and accuracy of transseptal access

AIMS

Percutaneous structural heart therapies, such as mitral value repair, require site-specific transseptal access (TSA). This can be challenging for interventional cardiologists. We describe a TSA catheter (TSAC) that utilises suction for enhanced control and puncture accuracy. Here, we aim to evaluate the safety and efficacy of the device.

METHODS AND RESULTS

Ex vivo interatrial septum preparations were dissected from swine (n=8) and diseased human hearts (n=6) to quantify TSAC suction and needle puncture force. TSAC suction was 6.5-fold greater than the opposing needle puncture force, and thus provides sufficient stabilisation for punctures. The safety and efficacy of TSAC was evaluated in a chronic mitral regurgitation swine model (n=10) and compared to a conventional TSA device. MR was induced by disrupting one to three mitral chordae tendineae, and the progression of heart disease was followed for three weeks. During device testing, procedure time and fluoroscopy exposure were not statistically different between devices. TSAC reduced septal displacement from 8.7±0.30 mm to 3.60±0.19 mm (p<0.05) and improved puncture accuracy 1.75-fold.

CONCLUSIONS

TSAC provides controlled TSA and improves puncture accuracy, while maintaining procedure time and workflow. These findings provide a strong rationale for a first-in-man study to demonstrate the clinical utility of the device.

Methodological approach in adopting off-pump coronary artery bypass surgery in a British cardiothoracic unit: Harefield experience

The theoretical and practical disadvantages of coronary artery bypass graft surgery using cardiopulmonary bypass with cardioplegic arrest are well reported in the literature. Encouraged by our work and others, we adopted a systematic approach to the application of off-pump coronary artery bypass surgery. We aimed to validate the non-selective use of the off-pump technique in all patients and assess the outcome in specific patient groups including: patients with ischaemic left ventricular dysfunction, female and high-risk patients. We investigated specific technical details related to off-pump surgery including: the potential effect of the distortion of the mitral valve on haemodynamic stability intraoperatively and the feasibility of sequential coronary artery bypass grafting using the off-pump technique. We also compared the outcome to the national United Kingdom performance in a risk-stratified manner. An extensive retrospective data review for comparative analysis of outcome was carried out at both local and multi-centre levels. This showed that off-pump surgery was feasible for all patients, and provided a better outcome in patients with ischaemic left ventricular dysfunction, female and high-risk patients. The distortion of the mitral valve contributed to the haemodynamic instability. In conclusion, off-pump surgery is safe and provides better outcome in specific patient groups.

Fixing Device for a Planar Object by Incorporating Jamming Transition Phenomenon and a Suction Unit

This paper presents a versatile method to install a small machining robot onto a planar or slightly curved object. Normally, gripping tools provide a rigid connection between a robot and a target. However, if there is no graspable area on the target, the gripper cannot perform well. To overcome this problem, we proposed a deformable device that works as a universal suction pad and that can hold an ungraspable target by utilizing the jamming transition phenomenon. We determined the effect of the type of grains on the jamming transition phenomenon in terms of stability under jammed conditions. By comparing the four types of grains, we found that the tetrahedral-shaped grains performed the best. Subsequently, we evaluated the performance of the device. The suction force was 166-N when the proposed device was affixed to a curved target. Next, we evaluated the stiffness of the device. The average deformations of the device were 0.10 mm, 0.35 mm, and 0.04 mm, respectively, when 50-N downward vertical, horizontal, and upward vertical directional loads were applied to the device, which was affixed to the curved target. The results suggest that the proposed device performed well in affixing a robot onto a target.

Coronary artery bypass grafting: Part 1--the evolution over the first 50 years

Surgical treatment for angina pectoris was first proposed in 1899. Decades of experimental surgery for coronary artery disease finally led to the introduction of coronary artery bypass grafting (CABG) in 1964. Now that we are approaching 50 years of CABG experience, it is appropriate to summarize the advancement of CABG into a procedure that is safe and efficient. This review provides a historical recapitulation of experimental surgery, the evolution of the surgical techniques and the utilization of CABG. Furthermore, data on contemporary clinical outcomes are discussed.

Percutaneous subxiphoid access to the epicardium using a miniature crawling robotic device

BACKGROUND

: To expand minimally invasive beating-heart surgery, we have developed a miniature 2-footed crawling robot (HeartLander) that navigates on the epicardium. This paradigm obviates mechanical stabilization and lung deflation, and avoids the access limitations of current approaches. We tested the locomotion of the device on a beating porcine heart accessed through a closed-chest subxiphoid approach.

METHODS

: HeartLander consists of 2 modules that are connected by an extensible midsection. It adheres to the epicardium using suction pads. Locomotion and turning are accomplished by moving the 2 modules in an alternating fashion using wires that run through the midsection between them. After a preliminary test with a plastic beating-heart model, we performed a porcine study in vivo. The device was inserted into the pericardial space through a subxiphoid incision, while the test was observed using a left thoracoscopy. The blood pressure and electrocardiogram were monitored, and vacuum pressure and driving forces on the wires were recorded.

RESULTS

: HeartLander traveled across the anterior and lateral surfaces of the beating heart without restriction, including locomotion forward, backward, and turning. The vacuum pressure was kept below 450 mm Hg at all times. The average maximum force during elongation was 1.86 ± 0.97 N, and during retraction was 1.24 ± 0.33 N. No adverse hemodynamic or electrophysiologic events were noted during the trial. No epicardial damage was found on the excised heart after the porcine trial.

CONCLUSIONS

: The current HeartLander prototype demonstrated safe and successful locomotion on a beating porcine heart through a closed-chest subxiphoid approach.

On-pump versus off-pump coronary artery bypass surgery: what is the status after ROOBY, DOORS, CORONARY and GOPCABE?

Off-pump coronary artery bypass surgery has been purported to be safer than conventional coronary artery bypass surgery performed using cardiopulmonary bypass. This theory was supported by a number of early series, but failed to be confirmed by a number of small, randomized, controlled trials. Conversely, it has been suggested that revascularization after off-pump surgery is associated with fewer grafts and lower graft patency, potentially leading to a higher risk of cardiovascular morbidity and need for repeated coronary interventions. Since 2009, four major randomized controlled trials have been published, increasing the level of evidence significantly.

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.

A Study Ex Vivo of the Effect of Epicardial Fat on the HeartLander Robotic Crawler

A tethered epicardial crawling robot known as HeartLander has been developed for minimally-invasive surgery on the beating heart. The crawler has been tested in vivo many times in a porcine model, a model which provides generally authentic conditions in many ways; however, the pigs tested generally have little epicardial fat, whereas the epicardial fat in human patients will be considerable. As a result, it is necessary to determine the effect of such fat on the performance of the crawler. In one experiment, using fresh ovine hearts ex vivo, clogging of the suction chambers of the crawler during sliding over tissue with active suction was investigated for a variety of thicknesses of epicardial fat. In a second experiment, the maximum traction force during each step was measured when sliding with active suction repeatedly over the same location for a variety of fat thicknesses. The clogging experiment showed accumulation of fat in the suction chamber, with the amount dependent on the state of the epicardial membrane, but the suction line did not clog. The traction experiment showed that traction was maintained in all cases except when the epicardial membrane was excised completely.

Landiolol reduces coronary artery motion in an open-chest porcine model: implications for off-pump coronary artery bypass surgery

Reduction of target coronary artery motion is imperative for successful off-pump coronary artery bypass surgery. We hypothesized that landiolol, a novel ultra-short-acting selective β-1 blocker, would reduce such coronary artery motion. To test this hypothesis, the motion of the left anterior descending artery of the porcine heart (n = 8) was analyzed by three-dimensional digital motion capture and reconstruction technology with or without continuous landiolol infusion. Landiolol (0.12 mg/kg/min) significantly decreased the heart rate (105 ± 16 vs. 90 ± 9 beats/min), three-dimensional distance moved (-20.4% vs. control), maximum velocity (-30.0% vs. control), acceleration (-31.1% vs. control), and deceleration (-28.6% vs. control) without inducing a significant change in the systolic blood pressure (85 ± 18 vs. 81 ± 22 mmHg), cardiac output (4.3 ± 1.4 vs. 4.1 ± 1.3 l/min), or pulmonary wedge pressure (7.8 ± 3.0 vs. 8.7 ± 2.9 mmHg). Landiolol reduces the heart rate and coronary artery motion with stable hemodynamics, which may facilitate performing precise anastomosis on the beating heart.

Five-year follow-up of a randomized comparison between off-pump and on-pump stable multivessel coronary artery bypass grafting. The MASS III Trial

BACKGROUND

Coronary artery bypass graft surgery with cardiopulmonary bypass is a safe, routine procedure. Nevertheless, significant morbidity remains, mostly because of the body's response to the nonphysiological nature of cardiopulmonary bypass. Few data are available on the effects of off-pump coronary artery bypass graft surgery (OPCAB) on cardiac events and long-term clinical outcomes.

METHODS AND RESULTS

In a single-center randomized trial, 308 patients undergoing coronary artery bypass graft surgery were randomly assigned: 155 to OPCAB and 153 to on-pump CAB (ONCAB). Primary composite end points were death, myocardial infarction, further revascularization (surgery or angioplasty), or stroke. After 5-year follow-up, the primary composite end point was not different between groups (hazard ratio 0.71, 95% CI 0.41 to 1.22; P=0.21). A statistical difference was found between OPCAB and ONCAB groups in the duration of surgery (240±65 versus 300±87.5 minutes; P<0.001), in the length of ICU stay (19.5±17.8 versus 43±17.0 hours; P<0.001), time to extubation (4.6±6.8 versus 9.3±5.7 hours; P<0.001), hospital stay (6±2 versus 9±2 days; P<0.001), higher incidence of atrial fibrillation (35 versus 4% of patients; P<0.001), and blood requirements (31 versus 61% of patients; P<0.001), respectively. The number of grafts per patient was higher in the ONCAB than the OPCAB group (2.97 versus 2.49 grafts/patient; P<0.001).

CONCLUSIONS

No difference was found between groups in the primary composite end point at 5-years follow-up. Although OPCAB surgery was related to a lower number of grafts and higher episodes of atrial fibrillation, it had no significant implications related to long-term outcomes. Clinical Trial Registration-URL: http://www.controlled-trials.com. Unique identifier: ISRCTN66068876.

Selective beta-1 receptor blockade further reduces the mechanically stabilized target coronary artery motion during beating heart surgery

OBJECTIVE

Adequate stabilization of anastomosis sites during off-pump coronary artery bypass is essential to obtain excellent graft patency. We examined the effect of beta-1 adrenergic receptor blockade on the target coronary artery motion by three-dimensional (3D) digital motion capture and reconstruction technology.

METHODS

Eight pigs underwent a sternotomy. Reflection markers were attached to the surface coronary arteries, followed by a mechanical stabilizer application. Two high-speed digital cameras captured two-dimensional (2D) motion of the markers from different angles. These 2D data were reconstructed into 3D data points, representing the motion of each coronary artery. Landiolol hydrochloride, a novel selective beta-1 receptor blocker, was infused intravenously after acquisition of control data.

RESULTS

Beta-1 receptor blockade decreased heart rate (105 ± 16 vs. 90 ± 9 beat/min; P = 0.007) without decreasing arterial blood pressure. The 3D distance moved (millimeter) during one cardiac cycle was significantly reduced on the left anterior descending (9.6 ± 2.8 vs. 6.6 ± 1.9 mm; P = 0.003), left circumflex (10.5 ± 6.3 vs. 6.4 ± 2.6 mm; P = 0.038), and right coronary (8.3 ± 3.6 vs. 6.5 ± 2.1 mm; P = 0.028) arteries. Reduction in the maximal velocity, maximal acceleration, and maximal deceleration of the anastomosis site in all coronary arteries was also found in a quantitative fashion.

CONCLUSIONS

Selective beta-1 receptor blockade significantly reduces the 3D motion at anastomosis sites on the beating heart, with stable systemic blood pressure. Further quantitative investigations of pharmacological stabilization are warranted to achieve better outcome of the patients undergoing off-pump coronary artery bypass surgery.

Effects of on-pump and off-pump coronary artery bypass grafting on left ventricular relaxation and compliance: a comprehensive perioperative echocardiography study

AIMS

The short-term effect of coronary artery bypass grafting (CABG) on diastolic function is only moderately investigated. Furthermore, it remains unknown whether avoidance of cardioplegic arrest by an off-pump CABG procedure has advantages over on-pump procedure regarding diastolic relaxation and compliance. We investigated whether components of diastolic function would be improved the day after CABG depending on the type of the surgical procedure.

METHODS AND RESULTS

Spontaneously breathing on-pump (n = 20) and off-pump CABG (n = 12) patients underwent a comprehensive transthoracic echocardiography examination the day before and the day after elective CABG, including transmitral and pulmonary vein flow parameters, colour M-mode flow propagation velocity (Vp) and tissue Doppler assessment of the average mitral annulus diastolic velocity (Em). Isovolumic relaxation and E-wave deceleration time were corrected for heart rate (IVRTcHR and DTcHR). Left ventricular (LV) relaxation time (τ) and LV operating stiffness (LVOS) were calculated. Overall and independent from operation type and preload, CABG decreased IVRTcHR (107 ± 20 vs. 93 ± 15 ms) (P < 0.01) and τ (54 ± 10 vs. 45 ± 10 ms) (P < 0.01), increased Vp (49 ± 22 vs. 75 ± 37 cm/s) (P < 0.01), and increased Em (6.6 ± 2.0 vs. 7.3 ± 1.3 cm/s, P = 0.06), indicating improved relaxation. LVOS increased (0.13 ± 0.06 vs. 0.22 ± 0.05 mmHg/mL) (P < 0.01), compatible with an impaired compliance. A similar improvement in relaxation and impairment in compliance were observed in both groups.

CONCLUSION

Myocardial relaxation improved the day after CABG irrespective of the use of cardiopulmonary bypass with cardioplegic arrest. Impairment in compliance could not be prevented by the avoidance of cardioplegia.

Effect of blower-mister devices on vasoreactivity of coronary artery bypass grafts

OBJECTIVE

Potential disadvantages, such as lower graft patency rates, that could lead to the need for more subsequent revascularization after off-pump coronary artery bypass grafting are discussed. One mechanism may involve endothelial damage originating from tools to facilitate a bloodless surgical field during anastomosis. We investigated the effect of the use of a blower-mister device on in vitro endothelial and contractile functions of human internal thoracic arteries and greater saphenous veins.

METHODS

The distal ends of both bypass graft types were exposed to the air and water stream of the device for 10 minutes, representing the usual time needed for completion of an anastomosis using the off-pump technique. Vessel segments of both groups were cut into 4-mm rings and stored in a modified Krebs-Henseleit solution. Contraction responses to U44619 and relaxation responses to acetylcholine, substance P, papaverine, and nitroprusside were evaluated.

RESULTS

Forty-eight artery ring segments from 8 patients were studied. Absolute maximum contraction to U44619 was significantly less in rings subjected to the blower-mister device than in controls (internal thoracic artery: 17.17 ± 2.57 mN vs 8.67 ± 4.54 mN, P < .048; greater saphenous vein: 28.33 ± 9.71 mN vs 11.42 ± 7.97 mN, P < .026). Control rings had significantly greater endothelium-dependent relaxation response to acetylcholine (mean difference 29.2% ± 3.4%, P < .001), whereas those subjected to the blower-mister device had reduced responses. Endothelium-independent relaxation to nitroprusside was not significantly different among the groups.

CONCLUSIONS

Vessels exposed to the air and water stream of a blower-mister device showed a reduced vasoreactivity. This effect should be studied further, especially if it contributes to lower graft patency rates in off-pump surgery.

Off-pump coronary artery bypass: techniques, pitfalls, and results

In an attempt to advance the surgical treatment of coronary artery disease, surgeons sought a way to offer the proven benefits of coronary revascularization and avoid the side effects of cardiopulmonary bypass by performing revascularization in the beating heart (off-pump coronary artery bypass). This review will describe the development and refinement of the technique, pitfalls to its widespread adoption, and an up-to-date assessment of current results.

A randomized comparative study of patients undergoing myocardial revascularization with or without cardiopulmonary bypass surgery: The MASS III Trial

The MASS III Trial is a large project from a single institution, The Heart Institute of the University of Sao Paulo, Brazil (InCor), enrolling patients with coronary artery disease and preserved ventricular function. The aim of the MASS III Trial is to compare medical effectiveness, cerebral injury, quality of life, and the cost-effectiveness of coronary surgery with and without of cardiopulmonary bypass in patients with multivessel coronary disease referred for both strategies. The primary endpoint should be a composite of cardiovascular mortality, cerebrovascular accident, nonfatal myocardial infarction, and refractory angina requiring revascularization. The secondary end points in this trial include noncardiac mortality, presence and severity of angina, quality of life based on the SF-36 Questionnaire, and cost-effectiveness at discharge and at 5-year follow-up. In this scenario, we will analyze the cost of the initial procedure, hospital length of stay, resource utilization, repeat hospitalization, and repeat revascularization events during the follow-up. Exercise capacity will be assessed at 6-months, 12-months, and the end of follow-up. A neurocognitive evaluation will be assessed in a subset of subjects using the Brain Resource Center computerized neurocognitive battery. Furthermore, magnetic resonance imaging will be made to detect any cerebral injury before and after procedures in patients who undergo coronary artery surgery with and without cardiopulmonary bypass.

TRIALS REGISTRATION

Clinical Trial registration information ISRCTN59539154 Off-pump vs. on-pump surgery in patients with Stable CAD MASS III.

A randomized comparative study of patients undergoing myocardial revascularization with or without cardiopulmonary bypass surgery: The MASS III Trial

The MASS III Trial is a large project from a single institution, The Heart Institute of the University of Sao Paulo, Brazil (InCor), enrolling patients with coronary artery disease and preserved ventricular function. The aim of the MASS III Trial is to compare medical effectiveness, cerebral injury, quality of life, and the cost-effectiveness of coronary surgery with and without of cardiopulmonary bypass in patients with multivessel coronary disease referred for both strategies. The primary endpoint should be a composite of cardiovascular mortality, cerebrovascular accident, nonfatal myocardial infarction, and refractory angina requiring revascularization. The secondary end points in this trial include noncardiac mortality, presence and severity of angina, quality of life based on the SF-36 Questionnaire, and cost-effectiveness at discharge and at 5-year follow-up. In this scenario, we will analyze the cost of the initial procedure, hospital length of stay, resource utilization, repeat hospitalization, and repeat revascularization events during the follow-up. Exercise capacity will be assessed at 6-months, 12-months, and the end of follow-up. A neurocognitive evaluation will be assessed in a subset of subjects using the Brain Resource Center computerized neurocognitive battery. Furthermore, magnetic resonance imaging will be made to detect any cerebral injury before and after procedures in patients who undergo coronary artery surgery with and without cardiopulmonary bypass.

TRIALS REGISTRATION

Clinical Trial registration information ISRCTN59539154 Off-pump vs. on-pump surgery in patients with Stable CAD MASS III.

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.

Off-pump versus on-pump coronary artery bypass graft surgery: differences in short-term outcomes and in long-term mortality and need for subsequent revascularization

BACKGROUND

Off-pump coronary artery bypass graft surgery (OPCAB) has been performed for many years, but its use is increasing in frequency, and it remains an open question whether OPCAB is associated with better outcomes than on-pump coronary artery bypass graft (CABG) surgery.

METHODS AND RESULTS

New York State patients who underwent either OPCAB with median sternotomy (13 889 patients) or on-pump CABG surgery (35 941 patients) between 2001 and 2004 were followed up via New York databases. Short- and long-term outcomes were compared after adjustment for patient risk factors and after patients were matched on the basis of significant predictors of type of CABG surgery. OPCAB had a significantly lower inpatient/30-day mortality rate (adjusted OR 0.81, 95% confidence interval [CI] 0.68 to 0.97), lower rates for 2 perioperative complications (stroke: adjusted OR 0.70, 95% CI 0.57 to 0.86; respiratory failure: adjusted OR 0.80, 95% CI 0.68 to 0.93), and a higher rate of unplanned operation in the same admission (adjusted OR 1.47, 95% CI 1.01 to 2.15). In the matched samples, no difference existed in 3-year mortality (hazard ratio 1.08, 95% CI 0.96 to 1.22), but OPCAB patients had higher rates of subsequent revascularization (hazard ratio 1.55, 95% CI 1.33 to 1.80). The 3-year OPCAB and on-pump survival rates for matched patients were 89.4% and 90.1%, respectively (P=0.20). For freedom from subsequent revascularization, the respective rates were 89.9% and 93.6% (P<0.0001).

CONCLUSIONS

OPCAB is associated with lower in-hospital mortality and complication rates than on-pump CABG, but long-term outcomes are comparable, except for freedom from revascularization, which favors on-pump CABG.

Training Models for Coronary Surgery

This paper reviews currently used training models for coronary artery bypass grafting (CABG). Training models for CABG are extremely helpful not only for training surgical techniques, but also for the evaluation of new technologies and for research on bypass graft pathophysiology. Wet-lab models serve as training platforms for surgical residents and allow the evaluation of new technology (e.g., robotically enhanced CABG). The right coronary artery to left anterior descending artery model on the slaughterhouse pig heart is easily available, cheap, and effective. In vivo animal models for CABG are much more sophisticated and cost intensive. Pigs and dogs are the most commonly used animals for CABG training. Offpump CABG techniques, totally endoscopic CABG, endoscopic gastroepiploic artery harvesting, and axillocoronary bypass grafting have been evaluated in animal models.

Three-dimensional quantification of cardiac surface motion: a newly developed three-dimensional digital motion-capture and reconstruction system for beating heart surgery

OBJECTIVE

This study aimed to evaluate our newly developed 3-dimensional digital motion-capture and reconstruction system in an animal experiment setting and to characterize quantitatively the three regional cardiac surface motions, in the left anterior descending artery, right coronary artery, and left circumflex artery, before and after stabilization using a stabilizer.

METHODS

Six pigs underwent a full sternotomy. Three tiny metallic markers (diameter 2 mm) coated with a reflective material were attached on three regional cardiac surfaces (left anterior descending, right coronary, and left circumflex coronary artery regions). These markers were captured by two high-speed digital video cameras (955 frames per second) as 2-dimensional coordinates and reconstructed to 3-dimensional data points (about 480 xyz-position data per second) by a newly developed computer program.

RESULTS

The remaining motion after stabilization ranged from 0.4 to 1.01 mm at the left anterior descending, 0.91 to 1.52 mm at the right coronary artery, and 0.53 to 1.14 mm at the left circumflex regions. Significant differences before and after stabilization were evaluated in maximum moving velocity (left anterior descending 456.7 +/- 178.7 vs 306.5 +/- 207.4 mm/s; right coronary artery 574.9 +/- 161.7 vs 446.9 +/- 170.7 mm/s; left circumflex 578.7 +/- 226.7 vs 398.9 +/- 192.6 mm/s; P < .0001) and maximum acceleration (left anterior descending 238.8 +/- 137.4 vs 169.4 +/- 132.7 m/s2; right coronary artery 315.0 +/- 123.9 vs 242.9 +/- 120.6 m/s2; left circumflex 307.9 +/- 151.0 vs 217.2 +/- 132.3 m/s2; P < .0001).

CONCLUSIONS

This system is useful for a precise quantification of the heart surface movement. This helps us better understand the complexity of the heart, its motion, and the need for developing a better stabilizer for beating heart surgery.

Vacuum-assisted apical suction devices induce passive electrical changes consistent with myocardial ischemia during off-pump coronary artery bypass graft surgery

OBJECTIVE

Off-pump coronary artery bypass graft surgery is common therapy to completely revascularize diseased hearts. In order to graft posterior arteries in this procedure, the heart must be lifted from the chest cavity and manipulated to expose the surgical field using an apical suction device. This suction device may cause unwanted myocardial ischemia.

METHODS

In this observational study, we measured myocardial electrical impedance, a parameter that responds to myocardial ischemia, as well as ST-segment changes during off-pump coronary artery bypass graft surgery in 12 patients with two-vessel coronary artery disease undergoing revascularisation of the left anterior descending and the posterior descending coronary arteries. During the posterior descending artery revascularisation phase of the procedure the apical suction device was oriented over the electrodes used to measure myocardial electrical impedance, thus allowing us the opportunity to assess myocardial ischemia in this region of the heart.

RESULTS

In these 12 patients, myocardial electrical impedance progressively increased under the suction device during posterior coronary artery revascularisation, suggesting that myocardial ischemia developed in this region of the myocardium. ST-segment changes were negligible while the heart was vertically displaced (and the suction device attached), but increased immediately when the heart was returned to the neutral anatomical position.

CONCLUSION

Our data suggest that the apical suction device may cause ischemia while the heart is vertically displaced and electrically disconnected from the body. Under these conditions, ST-segment changes may not detect myocardial ischemia. Myocardial electrical impedance has the potential to reliably detect intraoperative myocardial ischemia under these circumstances.

Off-Pump Myocardial Revascularization: Critical Analysis of 23 Years’ Experience in 3,866 Patients

BACKGROUND

Surgical myocardial revascularization without cardiopulmonary bypass (CPB) is not new, with the first consecutive series of patients appearing in the early eighties. There has been increased interest in this alternative approach, especially in patients with comorbidities. There is controversy regarding advantages, risks, and usefulness of this method of myocardial revascularization. We herein report a consecutive series of 3,866 patients, from the first case in September 1981 to the last in November 2004, analyzing applicability, mortality, morbidity, and surgical technique.

METHODS

From September 1981 to November 2004, 3,866 consecutive patients were revascularized without CPB. This figure represents an overall applicability of 30.8% considering a total of 12,553 revascularization procedures performed during this time. There were 2,822 males (73%) with ages from 12 to 93 years (median, 62 +/- 14). Mean grafts per patient was 1.9, and the internal mammary artery was used in 87.3% of cases. The main indications for surgery were chronic coronary insufficiency (89% of cases) and failure of angioplasty or stenting.

RESULTS

Hospital mortality was 1.9%, with low incidence of cerebrovascular accident (5 cases in the entire series). Morbidity, considering major postoperative complications, occurred in 12.5% of the patients. The applicability of the off-pump technique was 18% of cases in the beginning of our experience, increasing to 49% in the last 5 years with the use of stabilizers and maneuvers to expose posterior coronary branches.

CONCLUSIONS

Off-pump coronary surgery is an alternative method of myocardial revascularization that should be considered for every patient. The preference of this technique over conventional revascularization should be based on the surgeon's own experience, on the patient's preoperative condition and on the coronary anatomy. Off-pump myocardial revascularization represents an important development in coronary artery surgery. Over the years it has evolved into a valid form of surgery with the same safety as the conventional operation and with more advantages in high risk patients.

A simple atraumatic clamp technique without a stabilizer in off-pump CABG: how to do it

A method of stabilization of the heart and the coronary artery during the construction of the distal anastomosis in coronary artery procedures without cardiopulmonary bypass is described. The technique exposes and immobilizes the coronary artery, allowing a precise anastomosis on the beating heart. In addition, it is simple, safe, and inexpensive.

Off-pump coronary artery bypass grafting reduces postoperative neurologic complications

OBJECTIVE

Complications occurring after coronary artery bypass graft (CABG) surgery, particularly neurologic damage, have been mainly correlated with the use of cardiopulmonary bypass (CPB). The aim of this work was to compare postoperative outcomes of patients undergoing CABG surgery, with or without the use of CPB, focusing on neurologic events.

DESIGN

Observational study.

SETTING

University tertiary care hospital.

PARTICIPANTS

Two thousand seven hundred and forty consecutive patients who underwent CABG surgery in the period January 1998 to January 2003.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

For 738 patients, the operation was performed off-pump (OP group), and for 2002 patients CPB was used (CPB group). OP and CPB groups were compared with regard to preoperative status, anesthetic management, and postoperative outcomes, by means of univariate and multivariate analyses. Surgeons' propensity to operate off-pump was based on patients' age, renal conditions, and hemodynamics. Univariate and multivariate analyses showed that CPB was associated with a higher incidence of type I neurologic events compared with OP technique (2.1% versus 0.9%, odds ratio [OR]: 2.6, 95% confidence interval [CI], 1.2-5.9). A history of previous stroke (OR: 2.7, 95% CI, 1.2-5.9) and advanced age (OR: 1.06 per year, 95% CI, 1.02-1.09) were additional independent predictors of postoperative type I neurologic events.

CONCLUSIONS

In the authors' experience, off-pump CABG surgery offers some benefits compared with CPB in respect to major neurologic complications.

Acute effects of suction retraction on atrial hemodynamics and histology

OBJECTIVES

In minimally invasive and robotic mitral valve surgery, a blade retractor is used to elevate the left atrial roof, which often distorts tissue and impairs visualization. We tested the hemodynamic and histologic changes of intra-atrial suction, using a new suction retractor that may improve stabilization and visualization.

METHODS

Swine were divided into 3 equal (n = 4) groups: blade retractor, suction retractor, and arrested heart control. Left atrial ultrasonic crystals were used to record ejection fractions. After cardioplegic arrest, the atrium was opened and sampled for preretractor histology. Retractors remained in place for 1 hour, followed by postretractor histologic sampling. Controls were crossclamped for an equivalent time and postarrest histologic data obtained. Animals were weaned from bypass, data were collected for 4 hours, and postsacrifice atrial histologic samples were obtained.

RESULTS

The main effect due to treatment was not statistically significant ( P = .52) between the 3 groups, with the 4-hour average ejection fraction for blade retractor, suction retractor, and control being statistically equivalent at 33.3% +/- 8.3, 35.3% +/- 12.1, and 40.8% +/- 9.9 (mean +/- standard deviation), respectively. Histology showed equivalent amounts of myocyte fragmentation, interstitial edema, eosinophilia, and wavy fibers between blade retraction and suction retraction, while the latter showed slightly increased amounts of hemorrhage.

CONCLUSIONS

Atrial endocardial suction retraction appears to be safe with no acute changes in the left atrial ejection fraction or significant acute histologic differences, compared to blade retraction. Furthermore, intra-atrial suction may be applicable to procedures other than minimally invasive and robotic mitral valve repair for providing improved stabilization.

Off-pump total arterial revascularization: our experience

BACKGROUND AND AIM

Off-pump coronary artery bypass grafting with both the internal thoracic arteries, such as the Tector technique, can reduce the morbidity associated with extracorporeal circulation and aortic cross-clamp. The aim of the present study is to describe our experience and the results obtained.

METHODS

From April 1998 to December 2003, the off-pump Tector technique was performed on 743 patients, of whom 621 were male (83.5%), with a mean age of 65.3 +/- 9.5 years (23-90). Preoperative risk factors were diabetes mellitus in 29.5% and peripheral vasculopathy in 14.7% of the patients. Angiography showed left main disease in 25.6% and triple-vessel disease in 50.3% of the patients, with a mean ejection fraction of 60%+/- 13% (23-88). Both the internal thoracic arteries were harvested using the skeletonization technique and were anastomosed as "Y" or "T" grafts. Intraoperative graft patency was checked using a Doppler flowmeter.

RESULTS

A total of 2028 distal anastomoses were performed, the average being 2.7 (1 to 5) per patient. At least three distal anastomoses were undertaken in 62% of the patients. Postoperative complications included atrial fibrillation in 40 patients (5.4%), myocardial infarction in 24 (3.2%), mediastinitis and reoperation for bleeding in 7 (0.9%) and stroke in 3 (0.4%). Twenty-four patients (3.2%) died in the first month postoperatively.

CONCLUSIONS

The off-pump Tector technique appears to be safe, showing a low surgical morbidity.

The History and Development of Direct Coronary Surgery without Cardiopulmonary Bypass*

The history of direct myocardial revascularization without cardiopulmonary bypass dates to 1961 in the dawn of coronary artery surgery. With the introduction and development of techniques of extracorporeal circulation around the same time, beating heart surgery was largely abandoned. Over the subsequent decades, cardiopulmonary bypass and electromechanical cardioplegic arrest became popular as means of revascularization in a bloodless and motionless field. While coronary artery surgery on the arrested heart remained undisputed for decades, myocardial revascularization on the beating heart was pursued by a few pioneering surgeons around the world, based on the belief that coronary revascularization could be performed equally well without the detrimental effects of cardiopulmonary bypass and electromechanical arrest. Various concepts and techniques developed during the 1980s by these pioneers enabled minimally invasive coronary surgery to be performed in the early 1990s. This break from the mainstream allowed selective myocardial revascularization using a minimal incision and no cardiopulmonary bypass to develop and constructed a base for future extensive revascularizations off-pump. With the subsequent explosion of new techniques for coronary exposure and myocardial stabilization, complete revascularization without cardiopulmonary bypass became possible with consistent results. Emerging from the preview of only a few surgeons just a decade ago, off-pump surgery is currently one of the accepted modalities for complete myocardial revascularization worldwide. This paradigm shift in the approach to myocardial revascularization has led to exiting new future possibilities, such as beating heart totally endoscopic coronary artery surgery.

Ninety-degree anterior cardiac displacement in off-pump coronary artery bypass grafting: the Starfish cardiac positioner preserves stroke volume and arterial pressure

PURPOSE

In off-pump coronary surgery through sternotomy, exposure of posterior circumflex branches causes circulatory deterioration in both patients and pigs. We assessed cardiac pump function when displacing the pig heart anteriorly with a suction cardiac positioner.

DESCRIPTION

Six pigs (+/-80 kg) underwent sternotomy for hemodynamic instrumentation using catheter-tipped manometers and paced at 80 beats/min. Ultrasound flow probes were placed around the aorta and proximal coronary arteries. The heart was retracted anteriorly to 90 degrees with the Starfish cardiac positioner attached to the apex by means of suction (-400 mm Hg). Retraction was guided by cardiac output monitoring.

EVALUATION

Anterior displacement to 90 degrees facilitated full exposure of posterior arteries. Stroke volume and mean arterial pressure decreased to 94% +/- 13% (mean +/- SD, p = 0.135) and 95% +/- 13% (p = 0.09) of control values, respectively. Right and left ventricular end-diastolic pressure increased to 129% +/- 37% (p = 0.009) and to 128% +/- 57% (p = 0.235), respectively. Coronary flow remained unchanged. Additional 15-degree head-down positioning increased stroke volume to 113% +/- 17% (p = 0.015) and mean arterial pressure to 113% +/- 25% (p = 0.087) at the expense of further increased right and left ventricular end-diastolic pressure (186% +/- 63%, p < 0.001 and 157% +/- 49%, p < 0.001, respectively).

CONCLUSIONS

When lifting the porcine heart ninety degrees anteriorly, the Starfish cardiac positioner facilitated exposure of posterior branches and, when guided by cardiac output, preserved stroke volume and arterial pressure.

Endoscopic localization and assessment of coronary arteries by 13 MHz epicardial ultrasound

BACKGROUND

In totally endoscopic coronary artery bypass grafting the target coronary artery is difficult to locate and assess. We explored the capacity of a high-frequency epicardial ultrasound mini-transducer (Aloka, Tokyo, Japan) to endoscopically locate and assess the left anterior descending (LAD), third obtuse marginal (OM3), and right posterior descending (RDP) coronary arteries.

METHODS

In eight pigs, the LAD, OM3, and RDP were endoscopically exposed. The mini-transducer was manipulated by the "da Vinci" telemanipulation system (Intuitive Surgical, Inc, Mountain View, CA) over the unstabilized and stabilized epicardium to identify the target artery, obtain a scout scan, and both transverse and longitudinal images.

RESULTS

In both unstabilized and stabilized conditions, the LAD and RDP were identified within a median of 29 seconds. In stabilized conditions, assessment was complete in 112 seconds (92 to 205) (median with range) for the LAD and 140 seconds (54 to 197) for the RDP. Stabilization of the OM3 was required for identification (16 [5 to 60]) and assessment (111 [82 to 225]). Overall identification was correct in 23 of 24 arteries. The OM branches and RDP became fully exposed endoscopically with stroke volume (SV) and mean arterial pressure (MAP) remaining at 67% +/- 11% (mean +/- standard error of the mean) and 70% +/- 5% of baseline values, respectively. Scanning itself did not augment the decrease in SV and MAP significantly.

CONCLUSIONS

After proper endoscopic exposure and stabilization, robot-assisted epicardial ultrasound scanning enabled endoscopic identification and assessment of major coronary arteries within a median of 169 seconds per artery. Exposure, stabilization, and scanning were accompanied by an acceptable drop in stroke volume and mean arterial pressure.

Association between early and three month cognitive outcome after off-pump and on-pump coronary bypass surgery

OBJECTIVE

To describe the association between cognitive outcome in the first postoperative week and that at three months after both off-pump and on-pump coronary bypass surgery, and to make a direct comparison of early cognitive outcome after off-pump versus on-pump surgery.

DESIGN

Randomised trial with an additional prediction study within the two randomised groups.

SETTING

Three centres for heart surgery in the Netherlands.

PATIENTS

281 patients, mean age 61 years.

INTERVENTIONS

Participants were randomly assigned to off-pump or on-pump coronary bypass surgery.

MAIN OUTCOME MEASURES

Cognitive outcome, assessed by psychologists who administered neuropsychological tests one day before and four days and three months after surgery. A logistic regression model was used to study the predictive association between early cognitive outcome, together with eight clinical variables, and cognitive outcome after three months.

RESULTS

Cognitive outcome in the first week after surgery was determined for 219 patients and was a predictor of cognitive decline after three months. This association was stronger in on-pump patients (odds ratio (OR) 5.24, p < 0.01) than in off-pump patients (OR 1.80, p = 0.23). Early decline was present in 54 patients (49%) after off-pump surgery and 61 patients (57%) after on-pump surgery (OR 0.73, p = 0.25).

CONCLUSIONS

In patients undergoing first time coronary bypass surgery, early cognitive decline predicts cognitive outcome after three months. Early cognitive decline is not significantly influenced by the use of cardiopulmonary bypass.