Despite the increased prevalence of percutaneous coronary intervention (PCI) to treat coronary disease, coronary artery bypass graft (CABG) will continue to have a major role, particularly in patients with complex multivessel disease and diabetes mellitus. Currently, the majority of surgical revascularization is performed with the use of cardiopulmonary bypass (CPB), with most surgeons preferring to perform distal anastomoses on an arrested heart. Advocates of this approach cite low morbidity and mortality with outcomes that have continued to improve despite a surgical patient population with increasing comorbid conditions and more advanced and severe coronary disease.^1-3 However, complications, albeit infrequent, continue to plague a small percentage of patients undergoing CABG including stroke, renal failure, and respiratory failure. These complications occur not only because of the systemic inflammatory activation that occurs with extracorporeal circulation, but also because of the manipulation of the aorta required for cannulation, CPB, and aortic clamping. The interest in off-pump techniques was largely driven by the increased awareness of the deleterious effects of CPB and aortic manipulation.

According to the Society of Thoracic Surgeons Adult Cardiac Surgery Database (STS ACSD), off-pump CABG (OPCAB) use peaked in 2002 (23%) followed by a decline, accounting for approximately 17% of CABG cases in 2012.⁴ For most surgeons, the lack of compelling evidence in large randomized controlled trials (RCTs) supporting OPCAB over conventional on-pump coronary artery bypass (ONCAB) and suggestions of more frequent incomplete revascularization have been impediments to implementing this strategy in routine practice.^1-3,5,6 Nonetheless RCTs have almost uniformly demonstrated reduced transfusion requirements, lower postoperative serum myocardial enzyme levels, and shorter length of stay. Moreover, there are many retrospective trials showing a survival benefit as well as reduced morbidity with OPCAB. Retrospective database studies have much larger sample size and include mixed-risk patients. However, inherent selection bias may limit the interpretation of these results, despite advanced statistical methodology. For individual surgeons to consider implementing an off-pump approach, the following must be demonstrated: (1) equivalent short- and long-term patency rates; (2) complete revascularization; (3) reduced morbidity and even reduced mortality, especially in high-risk patients; and (4) cost efficiency both in the operating room and during the entire hospitalization. For certain high-risk subgroups, it would appear intuitive that avoiding the systemic effects of CPB as well as aortic manipulation would reduce the incidence of specific complications such as stroke and renal failure.

An off-pump approach is more technically challenging, with new risks not familiar to on-pump surgery. Therefore, OPCAB should be considered an advanced technique, not to be performed by all surgeons but by a select few who have trained with experts in OPCAB and who themselves perform large numbers of OPCAB procedures. Finally, there is greater appreciation that OPCAB should be performed in revascularization centers of excellence, incorporated into a comprehensive approach to revascularization, which includes minimally invasive CABG, hybrid, and total arterial revascularization.

Surgeon Experience

The adoption of OPCAB into clinical practice requires a commitment to learning a unique skill set. This is best achieved by focused training with an established OPCAB surgeon and routine adoption of OPCAB techniques such that the surgeon can employ this approach in patients likely to derive the most benefit. OPCAB surgery poses unique challenges to a surgeon who is accustomed to operating in a motionless and bloodless field. Furthermore, OPCAB requires an adept first and second assistant to provide exposure on a beating heart as well as excellent anesthesia management to maintain hemodynamics and alert the surgical team of potential hemodynamic problems. Thus, the commitment to OPCAB is usually tied to a belief that the technical challenges inherent in the procedure are worth overcoming so that the patient may benefit from the avoidance of CPB. Although the benefit may be small in low-risk patients, it is becoming apparent that certain high-risk subgroups may benefit from minimizing aortic manipulation as well as avoiding the systemic effects of CPB.

The inexperienced OPCAB surgeon embarking on the learning curve is best advised to choose his or her initial patients carefully and pay close attention to coronary anatomy and confounding patient variables. The surgeon must come to the operating room with an operative plan that is flexible enough to change as operative findings such as hemodynamic fluctuations, ischemia, or arrythmias. Early in a surgeon’s experience, it is probably prudent to exclude patients with difficult lateral wall targets, especially multiple lateral wall targets, severe left ventricular dysfunction, left main disease, or other complex cases (Table 21-1). Ideal early candidates for OPCAB include those undergoing elective primary coronary revascularization with good target anatomy, preserved ventricular function, and one to three grafts with easily accessible or no lateral wall targets. As experience is gained in OPCAB, this technique can be safely and effectively applied to the vast majority of patients requiring coronary artery bypass surgery. Just as important, however, is the experience to know when it is better to use CPB in patients in whom an off-pump approach will be exceedingly difficult, impractical, or poorly tolerated.

Patient Variables

The preoperative evaluation of patients for OPCAB demands careful planning and consideration for certain risk factors. We routinely perform screening carotid duplex ultrasonography on all patients over the age of 65, smokers, those with a carotid bruit, history of transient ischemic attack or stroke, left main coronary disease, peripheral vascular disease, or history of prior carotid intervention. The remainder of the preoperative evaluation is similar to ONCAB. In patients with a murmur, dyspnea, a history of aortic or mitral regurgitation (MR), or ventricular dysfunction on cardiac catheterization, preoperative echocardiography is warranted. It is important to be aware of right ventricular dysfunction, valvular regurgitation, or pulmonary hypertension as positioning during OPCAB can result in dramatic changes in these parameters. Overall, the clinical condition of the patient, the urgency of the operation, and ventricular function need to be carefully assessed to determine whether an off-pump approach will be tolerated. Patients with left ventricular dysfunction from a recent infarct pose a more difficult challenge than those with chronic ventricular dysfunction, with the former being much more sensitive to cardiac manipulation and displacement and more likely to develop intraoperative arrhythmias.

Anesthesia

As in other cardiac operations, all patients require invasive monitoring with a pulmonary artery catheter, arterial line, Foley catheter, and central venous line. We use transesophageal echocardiography liberally to provide valuable information about valvular regurgitation, regional myocardial function, and pulmonary hypertension. In our experience, a well-experienced anesthesia team is essential to maintaining stable hemodynamics and ensuring a smooth and uneventful operation. Unlike ONCAB, which requires active coordination among surgeon, anesthesiologist, and perfusionist, the anesthesiologist and surgeon must work especially closely to maintain hemodynamic stability during OPCAB. Subtle changes in hemodynamic status, gradual elevation in pulmonary artery pressures, frequent boluses, or increased requirement of inotropes and vasopressors to maintain hemodynamic stability, and rhythm changes can herald cardiovascular collapse. Such an event can reliably be avoided if these changes are verbalized and discussed between anesthesiologist and surgeon preemptively. When manipulating the heart, it is important for the surgeon to communicate these abrupt maneuvers to the anesthesia team so that appropriate action can be taken and inappropriate reactions (bolusing vasopressors) avoided. Changes in table position (Trendelenburg) can provide dramatic volume changes that affect cardiac output and blood pressure. Autotransfusion of intravascular volume from the lower extremities by Trendelenburg positioning should be the first maneuver to maintain hemodynamic stability. We prefer to avoid giving massive volumes of intravenous fluids, which requires later postoperative diuresis. Instead, aggressive use of Trendelenburg positioning and judicious use of alpha-adrenergic agents provides stable hemodynamics during distal anastamoses. This includes patients with pulmonary hypertension, mild or moderate ischemic MR, or left ventricular dysfunction in which cardiac manipulation and displacement as well as regional myocardial ischemia may be poorly tolerated without inotropic support. If preload conditions have been optimized, then vasopressor agents such as norepinephrine or Neo-Synephrine may be used to assist with maintaining adequate blood pressure during distal anastomoses. In our experience, effective communication with a well-experienced anesthesiologist is of paramount importance to ensure an uneventful off-pump operation.

Maintaining normothermia is critically important and requires more effort during OPCAB procedures, because the luxury of the CPB circuit for rewarming does not exist. This usually can be accomplished by infusing intravenous fluids through warmers, warming inhalational anesthetic agents, maintaining warm room temperatures before and during the procedure, and using convective forced-air warming systems (Bair Hugger; Arizant Healthcare, Eden Prairie, MN).

Anticoagulation regimens vary according to surgeon preference. For surgeons in their early experience, a full “pump” dose of heparin is reasonable in the event that conversion to CPB becomes necessary. Some surgeons continue to implement a full dose with 400 IU/kg to maintain an activated clotting time (ACT) of greater than 400 seconds; others use a half dose or 180 IU/kg, whereas others start with 10,000 IU and administer additional doses (3000 IU every half-hour) or a heparin infusion of 100 IU/min to maintain an ACT of 300 to 400 seconds. Reversal of anticoagulation with varying doses of protamine is usually administered to facilitate hemostasis.

Preparation

After the induction of anesthesia, patients are positioned, prepped, and draped in a standard fashion. At our institution, patients receive an aspirin rectal suppository (1000 mg) after induction. Aspirin 81 mg and clopidogrel (150 mg postoperatively, then 75 mg/day) are routinely administered early in the postoperative period after mediastinal drainage decreases well below 100 cc/h for 4 hours. This has not been associated with an increased risk of mediastinal reexploration.⁷ Because of the absence of CPB—related coagulopathy, patients may have a relative hypercoagulable perioperative state, which theoretically may jeopardize early graft patency. For this reason, we administer aspirin preoperatively, aspirin and clopidogrel early postoperatively, and then continue dual antiplatelet therapy in the postoperative period.

Endoscopic radial artery and saphenous vein conduits are harvested simultaneously during internal mammary artery (IMA) harvest. It is our practice to administer 5000 IU of heparin before endoscopic vein harvest to minimize thrombus formation within the conduit. Concern over graft quality with endoscopic vein harvest has prompted increased vigilance in atraumatic harvest technique to ensure adequate conduits for bypass.⁸ We routinely harvest skeletonized IMAs using a harmonic scalpel (Harmonic Synergy, Ethicon, Somerville, NJ). Skeletonized harvest of IMA grafts preserves sternal blood flow, leads to less postoperative dysesthesia, and may reduce sternal wound infection in higher risk patients such as those with diabetes mellitus. The Harmonic scalpel uses high-frequency mechanical vibration to cut and coagulate tissues and compared with electrocautery, minimizes surgical trauma to the sternum and reduces the risk of injury to the adjacent IMA.

After single or bilateral IMA harvest, the heparin dose is administered and the arterial conduits divided distally. The pericardium is incised in an inverted T-configuration, and then extended laterally along the diaphragm to facilitate cardiac displacement while avoiding injury to phrenic nerves. It is essential to free the left lateral pericardium from the diaphragm to allow the pericardium to be retracted to displace the heart, exposing the lateral wall of the left ventricle. We routinely dissect the left IMA distally to the bifurcation as the extra length is often necessary to avoid tension on the anastomosis during rightward displacement for lateral or inferolateral wall grafting. Dividing or removing the endothoracic fascia, skeletonizing the IMA during harvest, and dividing the left pericardium vertically toward the left phrenic nerve at the level of the pulmonary artery all provide for extra length and less tension on the anastomosis.

Several pericardial traction sutures are placed to assist with exposure and lateral displacement of the heart. To avoid compression on the right heart during lateral displacement, the right pericardium can be dissected along the diaphragm or the right pleural space opened widely to allow the heart to fall into the right chest during lateral displacement. An important traction suture is the “deep stitch,” which is placed approximately two-thirds of the way between the inferior vena cava and left pulmonary vein at the point where the pericardium reflects over the posterior left atrium (Fig. 21-1). Care should be taken with placement of this suture to avoid the underlying descending thoracic aorta, esophagus, left lung, and adjacent inferior pulmonary vein. This suture should be covered with a soft rubber catheter to prevent laceration of the epicardium during retraction. Furthermore, the manual elevation and compression of the heart required to take this stitch may be poorly tolerated in patients with marginal hemodynamics or significant left main coronary artery disease. In that case, grafting and reperfusion of the left anterior descending artery (LAD) should be accomplished before placing the deep pericardial traction suture.

Epiaortic Ultrasound

Epiaortic ultrasonography is used in all of our patients undergoing cardiac surgery, including OPCAB. It is a simple, noninvasive, and inexpensive tool for assessing the extent of atheromatous disease in the ascending aorta in preparation for aortic clamping or selection of an alternative clampless technique.⁹ Epiaortic ultrasound has been shown to be superior to transesophageal echocardiography or palpation alone in identifying aortic atheromatous lesions, especially in the mid- to distal ascending aorta.^10-12 The 8.5-MHz linear array probe is placed inside a sterile sleeve filled with sterile saline to act as a medium between the probe and the surface of the aorta (Fig. 21-2). The information allows the surgeon to individualize placement of aortic clamps and proximal anastomotic devices to minimize the risk of atheroembolism. In our practice, for aortic atherosclerosis grades 1 to 2 (Table 21-2), we will use a side-biting clamp or promixal anastomosis device. We will not clamp or manipulate grades 3 to 5, due to the risk of embolization. Rosenberger and coworkers,¹³ evaluated greater than 6000 patients with epiaortic ultrasound, suggested that the operative course was changed in 4% of patients because of the finding of aortic pathology, resulting in improved neurologic outcomes. Currently, intraoperative epiaortic ultrasound scanning is performed in only a small minority of centers. More data linking epiaortic ultrasonography to successful intraoperative decision-making and clinical outcomes should help to drive broader adoption of this promising diagnostic modality.

Exposure

Cardiac positioners and stabilizers have greatly increased the ability to manipulate the heart with minimal hemodynamic compromise. The two systems routinely used in our institution are the Medtronic Octopus Tissue Stabilizer and Starfish or Urchin Heart Positioner (Medtronic Inc., Minneapolis, MN) and the Maquet ACROBAT stabilizer and XPOSE positioner (Maquet, Radstat, Germany). Cardiac positioning devices are frequently placed away from the apex, especially to the left of the apex, to expose the lateral wall and branches of the left circumflex coronary artery (Figs. 21-3 and 21-4). They are generally placed on the apex to expose the anterior wall (LAD territory) and inferior wall (posterior descending territory) of the heart and may be placed on the acute margin to expose the right coronary artery (RCA; Fig. 21-5). The suction-based positioning is well tolerated as the heart is not compressed, thus maintaining its functional geometry. The coronary stabilizer devices are placed with minimal tension on the epicardium to allow for an area of mechanical stabilization. The anterior wall vessels often require only the coronary stabilizer for adequate exposure. The stabilizer is positioned along the caudal aspect of the retractor toward the left, with the retractor arm placed out of the way to prevent interference during the anastomosis. For the lateral and inferior wall vessels, the cardiac positioner is usually placed on the surgeon’s side at the most cephalad location of the retractor. A general rule is to put the stabilizer in the assistant’s way instead of the surgeon’s to prevent these devices from obstructing the surgeon’s view or interfering with hand positioning during suture placement.

In addition to positioners and stabilizers, manipulating the traction sutures can greatly enhance exposure. When the “deep stitch” is retracted toward the patient’s feet, it elevates the heart toward the ceiling and points the apex vertically with remarkably little change in hemodynamics. When retracted toward the patient’s left side, the heart rotates from left to right, exposing the lateral wall vessels. Variable tension on this stitch will enhance exposure to both the anterior and lateral wall. The left-sided pericardial sutures should be pulled taut and the right-sided sutures completely relaxed to avoid compression on the right heart during cardiac displacement. Pericardial sutures on both the right and left sides should never be under tension simultaneously. Manipulation of the operating table can also facilitate exposure. Placing the patient in steep Trendelenburg exposes the inferior wall. Turning the table sharply toward the right will aid with exposure of the lateral wall targets. For grafting the anterior wall vessels, the “deep stitch” can be pulled toward the patient’s left side and a coronary stabilizer can then be positioned to expose the target coronary artery (Fig. 21-6). Occasionally, a warm moist laparotomy pad can be placed between the heart and the posterolateral pericardium to assist with elevating the heart out of the pericardium.

In our experience, the most common mistakes leading to suboptimal exposure are

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  Incompletely freeing the left pericardium from the diaphragm

  
  
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  The “deep stitch” too far from the posterior left atrium

  
  
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  Not loosening the right-sided pericardial sutures during exposure of the left-sided targets

  
  
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  Compressing the heart against right pericardium, sternum, or retractor

  
  
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  Kinking the right ventricular outflow tract by excessive cephalad tilt of the vertical heart

  
  
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  Failing to combine the techniques of deep stitch, positioning device “off-apex”, elevation of the right sternal border on towels, and opening the right pleural space when needed

In preparation for distal anastomosis, a soft silastic retractor tape mounted on a blunt needle (Retract-o-tape, Quest Medical, Inc., Allen, TX) is placed widely around the proximal vessel for transient atraumatic occlusion. For inferior wall vessels, this suture can be displaced posteriorly and caudally by tying a posterior pericardial suture loosely around the retractor tape (Fig. 21-7). The pericardial retraction suture serves as a “pulley” that not only enhances coronary exposure and the surgeon’s view, but also keeps this retraction stitch from interfering with the sutures during the anastomosis. The field is kept free of blood with a humidified CO₂ blower (DLP, Medtronic, Inc.), which is managed by the scrub nurse or second assistant (Fig. 21-8). To avoid injury to the coronary endothelium, the blower should be set at the minimum setting needed for exposure (<5 L CO₂) and used only when passing the needle through the vessel. Occasionally an epicardial fat retractor can be used to expose the coronary target in patients with a large amount of epicardial fat.

Although a well-trained first assistant is necessary for providing an effortless anastomosis, the second assistant, often the scrub nurse, also plays a major role in exposure. This assistant usually stands to the right of the surgeon, and controls the CO₂ blower and the Cell Saver (Haemonetics Corp., Braintree, MA). The blower is used to keep the field free of blood and to open the target vessel and graft during suture placement. During the inferior wall or lateral wall targets, the second assistant may provide better exposure by standing to the surgeon’s left. In chronically occluded vessels that have collateral and/or retrograde flow, bleeding into the field can be controlled with another retractor tape distally, a MyOcclude device (United States Surgical Corp., Norwalk, CT), or an intracoronary shunt.^14,15 We use intracoronary shunts selectively rather than routinely, as at least one study demonstrated significant endothelial injury with its use.¹⁶ A final preparatory measure is to place temporary atrial or ventricular pacing cables before positioning the heart, particularly before RCA occlusion. As the heart is rotated toward the right, visualization of the right atrium is more difficult, so it is often prudent to place and test these cables before positioning.

Coronary Grafting

The current generation of coronary stabilizers relies on epicardial suction rather than compression to maintain epicardial tissue capture. A common mistake is to press down too hard on the epicardium, which will paradoxically cause both increased movement in the target region and impaired hemodynamics. The malleable pods of the stabilizers can be bent or manipulated in any direction to stabilize the target vessel. If there are concerns about hemodynamic stability during regional ischemia, the proximal vessel can be test occluded for 2 to 5 minutes and then reperfused, providing “preconditioning” of the subtended myocardium. Although not used routinely, preconditioning with two cycles of 2 minutes of LAD occlusion then 3 minutes of reperfusion before the first coronary anastomosis decreased postoperative myocardial enzyme release, heart rate increase, and restored ventricular function.¹⁷ During this time the graft can be prepared. This gives the surgeon some assurance before committing to the anastomosis by creating an arteriotomy. The anastomosis is otherwise performed in a manner identical to on-pump grafting. It is essential to continue communication with the anesthesia team so that adequate steps can be promptly taken if hemodynamic conditions deteriorate. For example, if pulmonary artery pressures begin to rise and mean arterial pressures begin to fall during a lateral wall anastomosis, several steps can be taken to avoid cardiovascular collapse: gently relaxing on the cardiac positioner or coronary stabilizer, steep Trendelenburg positioning, fluid boluses, inotropes, vasopressors, or pacing. If hemodynamic conditions continue to deteriorate, the safe next step is to place an intracoronary shunt, relax the retractor tape, and release both the stabilizer and positioner, allowing the heart to recover.¹⁵ At this point a decision must be made whether to convert “electively” to an on-pump procedure or complete the procedure off-pump. With better preparation (eg, fluids, inotropes, vasopressors, pacing, and shunt), the anastomosis can usually be completed off-pump. Another option for patients at high risk for complications of CPB is the use of intra-aortic balloon counterpulsation for mechanical support during cardiac displacement and positioning.

Sequence of Grafting

Careful assessment of the cardiac catheterization is imperative. When planning for OPCAB, particular attention needs to be paid to the collateralizing vessel(s), intramyocardial vessels, the size of the distal targets, the degree of stenosis, the complexity of coronary disease, and the number of lateral wall vessels requiring grafting. The sequence of grafting is important as regional myocardial perfusion is temporarily interrupted during anastomosis on the beating heart. As a general rule, the collateralized vessel(s) is grafted first and the collateralizing vessel is grafted last. For example, in patients with an occluded RCA with a posterior descending artery (PDA) supplied by collaterals from the LAD, grafting the LAD first would not only leave the anterior wall ischemic during the anastomosis, but also disrupt flow to the septum, inferior wall, and right ventricle. A more prudent approach would involve grafting the PDA first, then performing a proximal anastomosis to ensure adequate flow to the inferior wall while the proximal LAD is occluded during construction of the IMA-LAD anastomosis. Another scenario that may pose problems is a large moderately stenotic RCA. Not uncommonly, temporary occlusion will result in profound bradycardia and hypotension. The surgeon must be prepared to use an intracoronary shunt or provide temporary epicardial pacing. Additional options include a “proximals first” approach to allow adequate regional perfusion after completion of each distal anastomosis.

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  Perform anastomosis to completely occluded or collateralized vessel first

  
  
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  If LAD is not a collateralizing vessel, perform LAD-LIMA anastomosis first to allow for anterior wall perfusion during lateral and inferior wall positioning

  
  
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  Proximal anastomoses can be performed first to allow for perfusion of target vessels after each distal anastomosis. This can be helpful when cardiac positioning is not well tolerated

  
  
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  Beware of a large RCA with moderated proximal stenosis. Acute occlusion can cause bradycardia and hypotension. Be prepared for intracoronary shunt and epicardial pacing

  
  
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  Patients with moderate MR may not tolerate prolonged cardiac displacement, which can exacerbate MR, and lead to elevated PA pressures and subsequent hemodynamic deterioration. Grafting the culprit vessel causing papillary muscle dysfunction should be performed early in the procedure.

Proximal Anastomosis

Proximal anastomoses during OPCAB can be performed with the use of an aortic partial-occluding clamp after epiaortic ultrasound rules out aortic atherosclerosis or a proximal anastomosis device. In preparation for an aortic clamp, the systolic blood pressure is lowered (eg, <95 mm Hg), the clamp is applied and aortotomies are made with a 4.0-mm aortic punch. Proximal anastomoses are then performed using 5-0 or 6-0 polypropylene suture. Before tying down the most anterior proximal anastomosis, the clamp is released and the aorta is de-aired through the proximal anastomosis with clamps on vein grafts. After the suture is tied down, the vein grafts can be de-aired with a 25-gauge needle and clamps removed. Arterial grafts are not punctured but are allowed to bleed backward before clamp removal.

Unlike ONCAB, OPCAB provides the opportunity to minimize or completely avoid manipulation of the aorta by performing proximal anastomoses to in situ arterial grafts, or using clampless proximal anastomotic devices.^18-21 This is particularly relevant in patients with advanced aortic atheromatous disease detected by epiaortic ultrasound. Commercially available devices for clampless proximal anastomoses include the Heartstring III (Maquet Cardiovascular LLC, San Jose, CA), the PAS-Port Proximal Anastomosis System (Cardica Inc., Redwood City, CA), and the Enclose II (Vitalitec, Plymouth, MA). The Heartstring and Enclose devices create a near hemostatic seal with the inner surface of the ascending aorta that allows the creation of a hand-sewn anastomosis with a relatively bloodless field (Fig. 21-9). In contrast, the PAS-Port Proximal Anastomosis System is a fully integrated and automated system that attaches the vein graft to the aorta, instantaneously producing a reproducible anastomosis.^21-23

Graft Flow Measurement

We routinely quantitate graft flow using an intraoperative transit-time doppler flow meter (Medistim, Oslo, Norway). Acceptable values are flow > 15 mL/min, pulsatility index (the difference of maximum and minimum flow divided by the mean flow) <5 and diastolic fraction > 50% (for left-sided grafts). A post hoc analysis of the Veterans Affairs Randomized On/Off Bypass (ROOBY) Trial found that lower graft patency (non-FitzGibbon grade A) at 1 year was associated with low flow (<20 mL/min) or high pulsatility index (3-5 and >5) during intraoperative flow probe measurements.²⁴ Thus, any values outside of this range should alert the surgeon to examine the anastamoses and graft for potential revision unless unfavorable characteristics of the conduit, native coronary artery or distal run-off can readily account for the suboptimal doppler findings.

On-Pump Beating Heart Coronary Artery Bypass

Performing beating heart coronary artery bypass with CPB support is especially useful in certain clinical scenarios such as acute coronary syndromes with cardiogenic shock or in patients with severe left ventricular dysfunction where cardiac positioning and displacement will not be tolerated.^25,26 On-pump, beating heart techniques provide hemodynamic support while avoiding aortic clamping and the global ischemic insult associated with cardioplegic arrest.^27,28 However, this is an uncommonly used technique.