Exposure and mechanical stabilization in off-pump coronary artery bypass grafting via sternotomy

Lung Retraction for Exposure of Lateral Wall Vessels in Off-Pump Bypass Grafting

One of the major challenges in off-pump coronary artery bypass grafting (OPCAB) is ensuring adequate exposure of the lateral wall vessels. In most cases when the left pleura is opened during harvesting of the left internal thoracic artery , the lung frequently obscures the view. Reducing the tidal volume is practised by certain surgeons, which however in the presence of a single lumen tube affects both lungs and is best avoided in OPCAB. We describe a technique that allows adequate exposure of the circumflex artery and its branches without compromising the tidal volume.

A New Multisuction Cardiac Positioner for Multivessel Off-Pump Coronary Artery Bypass Grafting

Objective

To accomplish successful multivessel off-pump coronary artery bypass grafting, safe, reproducible, and effective exposure of all coronary territories is essential. For this purpose, we developed a new, simple, multisuction cardiac positioner.

Methods

This new cardiac positioner consists of 3 small independent suction cups and suction tubes made of silicone. Unlike an apical suction cardiac positioner, this positioner has no arm. The suction cups can be applied with negative pressure of 300 mm Hg to various surfaces of the ventricle, including not only the apex but also the lateral, inferior, and right ventricular walls, according to surgeon preference. We applied this positioner in 15 clinical multivessel off-pump coronary artery bypass procedures.

Results

In all cases, all target vessels including those on the lateral or inferior wall were successfully exposed and grafted without hemodynamic compromise. Surgical exposure, especially on the lateral and inferior walls, was quite similar to that of conventional coronary artery bypass graft procedures performed during cardiopulmonary bypass.

Conclusions

The multisuction cardiac positioner provided reproducible and easy access in multivessel off-pump coronary artery bypass surgery. This simple, variable, and inexpensive cardiac positioner may be used as a new tool to aid in the performance of successful multivessel off-pump coronary artery bypass surgery.

Deep Pericardial Traction Suture versus Vacuum-Assisted Apical Suction to Expose the Posterior Wall of the Heart in Off-Pump Coronary Artery Bypass: A Prospective, Randomized Study

<p><b>Background:</b> Displacement of the heart to expose the posterior vessels during off-pump coronary artery bypass (OPCAB) may cause hemodynamic instability. Deep pericardial traction suture (DPTS) and vacuum-assisted apical suction (VAS) with the Starfish positioning device help to provide good exposure without relevant hemodynamic changes. Our aim was to compare these two methods in patients undergoing multivessel OPCAB.</p><p><b>Methods:</b> We prospectively randomized 20 patients undergoing multivessel OPCAB to the use of VAS or DPTS. The Octopus device was used in both groups to stabilize the target vessel. Hemodynamic parameters, including venous oxygen content (SvO₂₎, cardiac index (CI), central venous pressure (CVP), mean arterial pressure (MAP), pulmonary artery pressure (PAP), and pulmonary capillary wedge pressure (PCWP), were measured before grafting (baseline), after heart positioning, and during performance of peripheral anastomoses.</p><p><b>Results:</b> Perioperative data for the two groups were similar. During exposure of the lateral wall, there were fewer hemodynamic changes in the DPTS group (increase in CVP) than in the VAS group (increases in CVP, PAP, and PCWP); the CVP was significantly higher in the DPTS group (<i>P</i> < .05). During exposure of the posterior wall, significant hemodynamic changes occurred only in the DPTS group (increase in PCWP). Values for all other parameters were similar, including anastomosis time, graft flow, postoperative myocardial enzymes, and inotropic support.</p><p><b>Conclusions:</b> Heart positioning during OPCAB with either VAS or DPTS is a safe and effective maneuver for exposure of coronary arteries. In our study, the use of the VAS device produced less hemodynamic impairment during exposure of the lateral and posterior walls.</p>

Superior Mesenteric Artery Blood Flow Modifications During Off-Pump Coronary Surgery

BACKGROUND

Patients undergoing cardiac surgery are at increased risk of gut hypoperfusion. During off-pump surgery, hemodynamic derangements at the time of heart displacement could reduce splanchnic perfusion, outweighing the beneficial effects of avoiding cardiopulmonary bypass. The purpose of this study is to assess, prospectively, blood flow modifications in the superior mesenteric artery during off-pump surgery using transesophageal echocardiography.

METHODS

In 19 patients undergoing multivessel elective off-pump coronary revascularization, systemic hemodynamics and superior mesenteric flow were assessed. Blood flow in the superior mesenteric artery was evaluated with duplex ultrasound using a transesophageal echo probe. Measurements were made four times: T0 (baseline), T1 (left anterior descendent anastomosis), T2 (heart displacement to expose the inferolateral and inferior walls), and T3 (closed chest, at the end of surgery).

RESULTS

Superior mesenteric blood flow significantly decreased at T2 (from 426.4 +/- 83.1 mL to 212.9 +/- 48.6 mL, p < 0.001), when also cardiac output was reduced. The percentage of the cardiac output directed toward the mesenteric arterial bed was also decreased at this time. At the end of surgery (T3), whereas cardiac output returned to the initial values, mesenteric flow was significantly increased compared with baseline, with a higher percentage of the systemic output flowing through the superior mesenteric artery.

CONCLUSIONS

Hemodynamic changes during off-pump coronary surgery induce a significant mesenteric hypoperfusion followed by a hyperemic response at the end of surgery. Transesophageal echo-Doppler allows the intraoperative measurement of blood flow distribution to splanchnic viscera.

Beating heart revascularization with or without cardiopulmonary bypass: evaluation of inflammatory response in a prospective randomized study

OBJECTIVE

On-pump beating heart coronary artery surgery provides the opportunity to examine the isolated effect of cardiopulmonary bypass. This prospective randomized study compares the early clinical outcomes and inflammatory response of patients undergoing elective on-pump and off-pump beating heart coronary artery bypass grafting.

METHOD AND PATIENTS

Thirty-seven consecutive patients undergoing elective coronary artery bypass grafting were recruited from a pool of 73 patients, with 19 patients randomized to on-pump beating heart surgery and 18 patients to off-pump coronary bypass surgery. Intraoperative events and postoperative outcomes were recorded. Plasma levels of interleukin-6, interleukin-8, and interleukin-10, tumor necrosis factor-alpha, and vascular cell adhesion molecule-1 were measured before the operation, intraoperatively, after the operation, and 4, 24, and 48 hours thereafter.

RESULTS

There was no significant difference in clinical outcomes between the 2 groups. The operating time was longer and consumption of platelets was greater for the on-pump beating heart group. There was no postoperative mortality or major complication in either group. There was significant elevation in the levels of interleukin-6, interleukin-8, and interleukin-10 and tumor necrosis factor-alpha during and immediately after the operations in the on-pump beating heart group when compared with the off-pump group. Levels of interleukin-8 (P =.01) and tumor necrosis factor-alpha (P =.0004) remained significantly elevated 4 hours after the operation in the on-pump beating heart group. The level of vascular adhesion molecule dropped significantly during the operation but was elevated 4 hours (P =.026) after the operation in the on-pump beating heart group.

CONCLUSION

The use of cardiopulmonary bypass alone without global myocardial ischemia secondary to aortic crossclamping and cardioplegic cardiac arrest can trigger intense inflammatory responses.

Effects of intracoronary shunts on coronary endothelial coating in the human beating heart

BACKGROUND

Local occlusion of coronary arteries during beating heart revascularization leads to injury of the arterial wall especially disturbing the integrity of the endothelium. The aim of this study was to elucidate the effects of intracoronary shunts versus local occlusion with elastic silicone loops on the beating heart in human coronary arteries by scanning electron microscopy.

METHODS

Coronary arteries of patients with dilated cardiomyopathy (n = 4) or ischemic heart disease (n = 8) undergoing heart transplantation were locally occluded either with a silicone loop or with a shunt inserted after arteriotomy. Unmanipulated segments of the coronary arteries served as controls. Integrity of the endothelial lining was observed with scanning electron microscopy.

RESULTS

Scanning electron microscopy revealed a statistically significant higher injury after shunting compared with controls (p < 0.001) and vessel loop occlusion (p < 0.001). There was no difference between both patient groups according to control specimens or after manipulation.

CONCLUSIONS

From this investigation we conclude that insertion of intracoronary shunts during beating heart surgery leads to severe endothelial denudation in human coronary arteries. Therefore, at present we recommend using intracoronary shunts selectively in cases in which critical ischemia or technical difficulties as a result of anatomic conditions are expected during anastomosis and avoiding routine shunt insertion into coronary arteries during beating heart revascularization.

Our experiences for off-pump coronary artery bypass grafting to the circumflex system

BACKGROUND

Complete revascularization has been difficult in off-pump coronary artery bypass grafting (OPCAB). Hemodynamic deterioration often prevents access to the circumflex territory. This study presents instrumentation for accessing the circumflex territory, and our clinical experience.

METHODS

From August 1999 through December 2002, 140 patients underwent OPCAB via sternotomy in our institution. The 114 requiring reconstruction of the circumflex artery are the subjects of this study. There were no exclusion criteria. A series of techniques and instruments were developed to provide access to the circumflex area while hemodynamic stability was preserved, including the left pericardial traction technique, compression of the right pericardium, a right sternal retractor, and a type of shunt tube.

RESULTS

Patients received an average of 3.2 grafts (range, 2 to 6). Complete revascularization was achieved in 95% of the cases. Complications included respiratory insufficiency (0.8%), renal dysfunction (7%), and sternal wound infection (0.8%). Blood transfusions were required in 10 patients (8%). No patient suffered perioperative myocardial infarction or stroke. No operation was converted to cardiopulmonary bypass. There was no operative death. Predischarge angiography demonstrated a 99% patency rate.

CONCLUSIONS

With our techniques and instruments, off-pump coronary revascularizaion of the circumflex area may be performed safely to achieve complete revascularization. Early clinical results are excellent, but long-term longitudinal follow-up is required to assess the future effectiveness of OPCAB procedure with our techniques.

Acute effects of beating heart coronary surgery on left ventricular performance

BACKGROUND

The increasing use of off-pump bypass grafting (OPCABG), requires an evaluation of its effects on left ventricular (LV) performance.

METHODS

In 8 patients with multivessel coronary disease who were undergoing to off-pump coronary artery bypass grafting, LV performance was analyzed from the pressure-volume (P-V) plane by the conductance catheter technique. Measurements were performed at base line, after the exposure of the vessels, after the application of the stabilization system, and at the end of the procedure.

RESULTS

No significant changes in heart rate, LV end-systolic volume, LV end-diastolic pressure, mean pulmonary artery, and mean systemic blood pressure were observed in the various stages of the procedure. Cardiac index decreased during left anterior descending coronary artery grafting after application of the stabilizer with a concomitant decrease in LV end-diastolic volume, together with decreases in LV peak negative -dP/dt and increases in tau, indicating an impairment of LV relaxation but without a change in preload recruitable stroke work, indicating preserved LV contractile state. Exposure of posterior and lateral vessels induced a decrease in cardiac index and preload recruitable stroke work without a decrease in LV preload, indicating a decrease in LV contractile state together with a decrease in peak -dP/dt and increase in tau, indicating an impairment in LV relaxation

CONCLUSIONS

Off-pump coronary artery bypass grafting can be performed without decreasing LV performance. Major cardiac displacement like that used for posterior and lateral exposure induces acutely significant decrease in LV contractile state.

Retropericardial hematoma complicating off-pump coronary artery bypass surgery

We report the case of a retropericardial hematoma after triple-vessel off-pump coronary artery bypass grafting. Transesophageal echocardiography demonstrated a retropericardial hematoma that compressed the left atrium anteriorly and suppressed cardiac function. Injury to the pulmonary vein during placement of deep pericardial sutures and postoperative infusion of heparin were the likely causes of this rare but potentially fatal complication of an off-pump bypass operation.