Change in right ventricular function during off-pump coronary artery bypass graft surgery

Inhaled iloprost in off-pump coronary artery bypass surgery: a randomized controlled trial

PURPOSE

Mechanical cardiac constraint during off-pump coronary artery bypass surgery (OPCAB) causes right ventricle (RV) compression and increased pulmonary artery pressure (PAP), which may further compromise RV dysfunction. We aimed to assess the effect of inhaled iloprost, a potent selective pulmonary vasodilator, on the cardiac index (CI) during mechanical constraint. The secondary aim was to determine the resultant changes in the hemodynamic and respiratory parameters.

METHODS

A total of 100 adult patients with three-vessel coronary artery disease who had known risk factors for hemodynamic instability (congestive heart failure, mean PAP ≥ 25 mm Hg, RV systolic pressure ≥ 50 mm Hg on preoperative echocardiography, left ventricular ejection fraction < 50%, myocardial infarction within one month of surgery, redo surgery, and left main disease) were enrolled in a randomized controlled trial. The patients were randomly allocated to the control or iloprost groups at a 1:1 ratio, in which saline and iloprost (20 μg) were inhaled for 15 min after internal mammary artery harvesting, respectively. Cardiac index was measured by pulmonary artery catheterization.

RESULTS

There were no significant intergroup differences in CI during grafting (P = 0.36). The mean PAP had a significant group-time interaction (P = 0.04) and was significantly lower in the iloprost group at circumflex grafting (mean [standard deviation], 26 [3] mm Hg vs 24 [3] mm Hg; P = 0.01). The remaining hemodynamic parameters were similar between the groups.

CONCLUSION

Inhaled iloprost showed a neutral effect on hemodynamic parameters, including the CI and pulmonary vascular resistance index, during OPCAB.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT04598191); first submitted 12 October 2020.

First Experience With the Triolifter, a Novel Device for Organ Fixation Used as a Heart Positioner in Cardiac Surgery

We describe our first experience with the Triolifter (Fuji Systems, Yokohama, Japan) in cardiac surgery. The Triolifter is a less expensive, novel organ fixation device developed as a fixation indenter mainly for traction of the lung under video-assisted surgery and is now available in Japan. An 84-year-old man diagnosed with unstable angina pectoris underwent emergency coronary artery bypass grafting (CABG) under cardiac arrest. Following the declamping of the aorta and the resumption of the beating heart, bleeding from the left anterior descending artery (LAD) anastomosis site was observed. The Triolifter was used as a heart positioner to expose the anastomosis site for hemostasis in the setting of an on-pump beating heart. Hemostasis of the posterior descending artery (PDA) anastomosis site could also be confirmed by traction of the right ventricular anterior wall using the Triolifter. It could be effectively and safely used with neither significant subepicardial hematoma nor epicardial injury. In Japan, the Triolifter might be used as one of the insurance-covered devices in off-pump CABG in the future, but globally, it could also be used in on-pump CABG without hesitation because it is so inexpensive.

Perioperative Right Ventricular Dysfunction and Abnormalities of the Tricuspid Valve Apparatus in Patients Undergoing Cardiac Surgery

Right ventricular (RV) dysfunction frequently occurs after cardiac surgery and is linked to adverse postoperative outcomes, including mortality, reintubation, stroke, and prolonged ICU stays. While various criteria using echocardiography and hemodynamic parameters have been proposed, a consensus remains elusive. Distinctive RV anatomical features include its thin wall, which presents a triangular shape in a lateral view and a crescent shape in a cross-sectional view. Principal causes of RV dysfunction after cardiac surgery encompass ischemic reperfusion injury, prolonged ischemic time, choice of cardioplegia and its administration, cardiopulmonary bypass weaning characteristics, and preoperative risk factors. Post-left ventricular assist device (LVAD) implantation RV dysfunction is common but often transient, with a favorable prognosis upon resolution. There is an ongoing debate regarding the benefits of concomitant surgical repair of the RV in the presence of regurgitation. According to the literature, the gold standard techniques for assessing RV function are cardiac magnetic resonance imaging and hemodynamic assessment using thermodilution. Echocardiography is widely favored for perioperative RV function evaluation due to its accessibility, reproducibility, non-invasiveness, and cost-effectiveness. Although other techniques exist for RV function assessment, they are less common in clinical practice. Clinical management strategies focus on early detection and include intravenous drugs (inotropes and vasodilators), inhalation drugs (pulmonary vasodilators), ventilator strategies, volume management, and mechanical support. Bridging research gaps in this field is crucial to improving clinical outcomes associated with RV dysfunction in the near future.

The Dilemma: Whether to Proceed or Postpone a Patient With Pyrexia at Induction of Anesthesia for Coronary Artery Bypass Graft Surgery

Routine surgery may be postponed if a patient has high white blood cells (WBC) and/or pyrexia. However, postponement carries the risk of myocardial ischaemia or infarction in a patient having coronary artery bypass graft (CABG) surgery. Our case raises this dilemma in a high-risk patient that was further compromised by acute right ventricular (RV) dysfunction. A 51-year-old diabetic with end-stage renal failure, chest pain, and a recent non-ST elevation myocardial infarction (NSTEMI) who had previously refused surgery now presented for urgent CABG. During central line insertion, he started shivering and stated that he felt cold. His temperature was not measured pre-intubation, but he felt warm to the touch with no chest pain. Blood pressure (BP) 190/80 mmHg and HR 110 bpm. Iv glyceryl nitrate (GTN) and fentanyl controlled the BP. Cerebral oximetry was used to measure brain regional saturation (rSO₂) with probes placed on the forehead pre-induction. Post-intubation his temperature was 38.1°C, end-tidal carbon dioxide (EtCO₂) 9.2 kPa, heart rate (HR) 120 bpm. His recent NSTEMI and surgical referral two years previously meant that his ischaemic risk was high, and we decided to proceed with the surgery. During the internal mammary artery (IMA) harvesting and use of a retractor (IMAR), there was a steady fall in the rSO₂ readings along with hypotension and an increase in central venous pressure (CVP) becoming critical after 60 minutes. At this point, the patient went onto cardiopulmonary bypass (CPB). The patient required triple vasoactive support to wean off CPB. In the intensive care unit (ICU), he required immediate support for RV failure, including nitric oxide. The next day, the patient grew Gram-negative blood cultures. In hindsight, we should have checked his temperature before induction and postponed or postponed post-induction. Regarding the IMAR or any retractor, the operating team will pay much closer attention to any haemodynamic changes resulting from their use and act accordingly. 

Preoperative right ventricular dysfunction requires high vasoactive and inotropic support during off-pump coronary artery bypass grafting

Objectives

The association of preoperative RV function with hemodynamics during OPCAB or emergency conversion is not clear. The aim of this study was to investigate the association of vasoactive-inotropic score with tricuspid annular plane systolic excursion and tricuspid regurgitation in off-pump coronary artery bypass grafting, and to calculate the optimal cut-off value of tricuspid annular plane systolic excursion to predict emergency conversion to cardiopulmonary bypass.

Methods

Patients over 20 years of age who had undergone off-pump coronary artery bypass grafting between April 2015 and March 2020 were enrolled in this study. We retrospectively assessed the association of intraoperative maximum “vasoactive-inotropic score”, a weighted sum of various inotropes and vasoconstrictors, with tricuspid annular plane systolic excursion and tricuspid regurgitation. A receiver operating characteristic curve of conversion on tricuspid annular plane systolic excursion was also constructed.

Results

135 patients were included in final analysis. Conversion was performed in 10 cases. Multiple regression analysis showed that tricuspid annular plane systolic excursion, mild or more tricuspid regurgitation and experienced surgeon were significantly related to vasoactive-inotropic score. The receiver operating characteristic curve to predict conversion by tricuspid annular plane systolic excursion showed an optimal cut-off value of 15.0 mm and area under the curve of 0.808.

Conclusions

Tricuspid annular plane systolic excursion and tricuspid regurgitation were associated with vasoactive-inotropic score in off-pump coronary artery bypass grafting. The optimal cut-off value of tricuspid annular plane systolic excursion to predict emergency conversion was 15 mm.

Cardiac Output Values and Correlation of Renal Injury with Neutrophil Gelatinase-Associated Lipocalin Levels in Off-Pump Coronary Artery Bypass Patients

Objective

To investigate the correlation between cardiac output values and renal neutrophil gelatinase-associated lipocalin (NGAL) levels as a biomarker of renal ischemia.

Methods

Forty patients, who underwent off-pump coronary artery bypass (OPCAB) surgery and in whom the positioning of the heart was fixed with simple suspension sutures without a mechanical stabilizer, were included in the study. Continuous cardiac output (CO) measurements were recorded using the arterial pressure waveform analysis method (FloTrac sensor system) in the perioperative period. CO was recorded every minute during non-anatomical cardiac positioning for left anterior descending artery (LAD), diagonal artery (D), circumflex artery (Cx), and right coronary artery (RCA) bypasses. Serum NGAL samples were analyzed in the preoperative, perioperative, and postoperative periods.

Results

The CO values measured at various non-anatomical cardiac positions during distal anastomosis for LAD, D, Cx, and RCA were significantly lower than pre- and postoperative values measured with the heart in normal anatomical position (3.45±0.78, 2.9±0.71, 3.11±0.56, 3.19±0.81, 5.03±1.4, and 4.85±0.78, respectively, P=0.008). There was no significant difference between CO values measured at various non-anatomical cardiac positions during distal anastomosis. Although there was no significant correlation between NGAL levels and age, duration of surgery, preoperative CO, D-CO, RCA-CO, and postoperative CO measurements, there was a significant correlation between NGAL levels and LAD-CO (P=0.044) and Cx-CO (P=0.018) at the postoperative 12^th hour.

Conclusion

Full revascularization may be achieved by employing the OPCAB technique while using simple suspension sutures without a mechanical stabilizer and by providing safe CO levels and low risk of renal ischemia.

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.

Right ventricular function following surgical aortic valve replacement and transcatheter aortic valve implantation: A cardiovascular MR study

OBJECTIVE

The response of the RV following treatment of aortic stenosis is poorly defined, reflecting the challenge of accurate RV assessment. Cardiovascular magnetic resonance (CMR) is the established reference for imaging of RV volumes, mass and function. We sought to define the impact of transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) upon RV function in patients treated for severe aortic stenosis using CMR.

METHODS

A 1.5T CMR scan was performed preoperatively and 6months postoperatively in 112 (56 TAVI, 56 SAVR; 76±8years) high-risk severe symptomatic aortic stenosis patients across two UK cardiothoracic centres.

RESULTS

TAVI patients were older (80.4±6.7 vs. 72.8±7.2years, p<0.05) with a higher STS score (2.13±0.73 vs. 5.54±3.41%, p<0.001). At 6months, SAVR was associated with a significant increase in RV end systolic volume (33±10 vs. 37±10ml/m², p=0.008), and decrease in RV ejection fraction (58±8 vs. 53±8%, p=0.005) and tricuspid annular plane systolic excursion (22±5 vs. 14±3mm, p<0.001). Only 4 (7%) SAVR patients had new RV late gadolinium hyper-enhancement with no new cases seen in the TAVI patients at 6months. Longer surgical cross-clamp time was the only predictor of increased RV end systolic volume at 6months. Post-TAVI, there was no observed change in RV volumes or function. Over a maximum 6.3year follow-up, 18(32%) of TAVI patients and 1(1.7%) of SAVR patients had died (p=0.001). On multivariable Cox analysis, the RV mass at 6m post-TAVI was independently associated with all-cause mortality (HR 1.359, 95% CI 1.108-1.666, p=0.003).

CONCLUSIONS

SAVR results in a deterioration in RV systolic volumes and function associated with longer cross-clamp times and is not fully explained by suboptimal RV protection during cardiopulmonary bypass. TAVI had no adverse impact upon RV volumes or function.

Placing a saline bag underneath the heart enhances transgastric transesophageal echocardiographic imaging during cardiac displacement for off-pump coronary artery bypass surgery

OBJECTIVE

The authors hypothesized that placing a saline bag (saline-filled surgical glove) underneath a displaced heart would improve ultrasound transmission for transgastric (TG) imaging and transesophageal echocardiography (TEE) to visualize left ventricular regional wall motion (LV-RWM) during cardiac displacement for off-pump coronary artery bypass (OPCAB) surgery.

DESIGN

Prospective observational study.

SETTING

Tertiary University Hospital.

PARTICIPANTS

Adult patients undergoing OPCAB surgery.

INTERVENTIONS

Intraoperative TEE examination

MEASUREMENT AND MAIN RESULTS

For off-line analyses of LV-readable segments, mid-esophageal (ME, 4-chamber, 2-chamber, and long-axis) and TG (basal- and mid-short-axis) TEE views were recorded under 3 different intraoperative conditions in 13 cases of OPCAB surgery: Before cardiac displacement (Tcontrol), after cardiac displacement (Tdisplaced), and after placing the saline bag underneath the displaced heart (Tsaline-bag). There were more LV-readable segments in the 17-segment model using integrated ME and TG views(ME + TG views) at Tsaline-bag and Tcontrol (mean[95% confidence interval], 17[17-17] and 17[17-17]) than using ME+TG at Tdisplaced (15[15-16], P = 0.002 and P<0.001, respectively). Using ME + TG views provided more LV-readable segments in the 17-segment model than using ME views at Tsaline-bag (vs. 16[14-16], P < 0.001), but not at Tdisplaced (vs. 15[14-15]). Incidences of inadequate RWM monitoring (LV-readable segments<14/17 using ME + TG views) at Tsaline-bag and Tcontrol (all 0/13) were less frequent than at Tdisplaced (3/13, all P = 0.038). There were more LV-readable segments in TG basal- and mid-short-axis views at Tsaline-bag (median [range], 6[5-6] and 5[5-6]) than at Tdisplaced (0[0-2] and 0[0-1], all P < 0.05).

CONCLUSIONS

Placing a saline bag underneath the displaced heart enhances the ability of TEE to visualize global LV-RWM by improving TG TEE imaging during OPCAB surgery.

Accuracy of cardiac output measurements during off-pump coronary artery bypass grafting: according to the vessel anastomosis sites

Background

During beating heart surgery, the accuracy of cardiac output (CO) measurement techniques may be influenced by several factors. This study was conducted to analyze the clinical agreement among stat CO mode (SCO), continuous CO mode (CCO), arterial pressure waveform-based CO estimation (APCO), and transesophageal Doppler ultrasound technique (UCCO) according to the vessel anastomosis sites.

Methods

This study was prospectively performed in 25 patients who would be undergoing elective OPCAB. Hemodynamic variables were recorded at the following time points: during left anterior descending (LAD) anastomosis at 1 min and 5 min; during obtuse marginal (OM) anastomosis at 1 min and 5 min: and during right coronary artery (RCA) anastomosis at 1 min and 5 min. The variables measured including the SCO, CCO, APCO, and UCCO.

Results

CO measurement techniques showed different correlations according to vessel anastomosis site. However, the percent error observed was higher than the value of 30% postulated by the criteria of Critchley and Critchley during all study periods for all CO measurement techniques.

Conclusions

In the beating heart procedure, SCO, CCO and APCO showed different correlations according to the vessel anastomosis sites and did not agree with UCCO. CO values from the various measurement techniques should be interpreted with caution during OPCAB.

Haemodynamic changes during left anterior descending artery exposure in off-pump coronary artery bypass: comparison between use of moist laparotomy pads and deep pericardial traction sutures for heart displacement

Haemodynamic changes occurring during heart displacement, using moist laparotomy pads placed behind the heart (PAD group, n = 26) or deep pericardial traction sutures (DPS group, n = 25) to facilitate exposure of the left anterior descending artery during off-pump coronary artery bypass surgery, were compared. Haemodynamic variables were assessed before and 10 min after displacement of the heart. The central venous pressure, mean pulmonary artery pressure and pulmonary capillary wedge pressure increased in both groups. After heart displacement in the PAD group, the cardiac index, stroke volume index, mixed venous oxygen saturation, right ventricular ejection fraction and left ventricular stroke work index decreased significantly, and the systemic vascular resistance and pulmonary vascular resistance increased significantly; these parameters remained unchanged in the DPS group. It was concluded that displacement of the heart using moist laparotomy pads caused significant haemodynamic derangement compared with that caused by deep pericardial traction sutures.

The effect of milrinone infusion on right ventricular function during coronary anastomosis and early outcomes in patients undergoing off-pump coronary artery bypass surgery

Background

During coronary anastomosis in off-pump coronary artery bypass surgery (OPCAB), hemodynamic alternations can be induced by impaired diastolic function of the right ventricle. This study was designed to examine the effect of milrinone on right ventricular function and early outcomes in patients undergoing OPCAB.

Methods

Forty patients undergoing OPCAB were randomly assigned in a double-blind manner to receive either milrinone (milrinone group, n = 20) or normal saline (control group, n = 20). Hemodynamic variables were measured after pericardiotomy (T1), 5 min after stabilizer application for anastomosis of the left anterior descending coronary artery (LAD, T2), the obtuse marginalis branch (OM, T3), the right coronary artery (RCA, T4), 5 min after sternal closure (T5), and after ICU arrival. The right ventricular ejection fraction (RVEF) and right ventricular volumetric parameters were also measured using the thermodilution technique. For evaluation of early outcomes, the 30-day operative mortality and morbidity risk models were used.

Results

There was no significant difference in hemodynamic variables, including mean arterial pressure, between the 2 groups, except for the cardiac index and RVEF. The cardiac index and RVEF were significantly greater at T3 in the milrinone group than in the control group.

Conclusions

Continuous infusion of milrinone demonstrated a beneficial effect on cardiac output and right ventricular function in patients undergoing OPCAB, especially during anastomosis of the graft to the OM artery, and it had no adverse effect on early outcomes.

Left ventricular diastolic dysfunction of the cardiac surgery patient; a point of view for the cardiac surgeon and cardio-anesthesiologist

BACKGROUND

Left ventricular diastolic dysfunction (DD) is defined as the inability of the ventricle to fill to a normal end-diastolic volume, both during exercise as well as at rest, while left atrial pressure does not exceed 12 mm Hg. We examined the concept of left ventricular diastolic dysfunction in a cardiac surgery setting.

MATERIALS AND METHODS

Literature review was carried out in order to identify the overall experience of an important and highly underestimated issue: the unexpected adverse outcome due to ventricular stiffness, following cardiac surgery.

RESULTS

Although diverse group of patients for cardiac surgery could potentially affected from diastolic dysfunction, there are only few studies looking in to the impact of DD on the postoperative outcome; Trans-thoracic echo-cardiography (TTE) is the main stay for the diagnosis of DD. Intraoperative trans-oesophageal (TOE) adds to the management. Subgroups of DD can be defined with prognostic significance.

CONCLUSION

DD with elevated left ventricular end-diastolic pressure can predispose to increased perioperative mortality and morbidity. Furthermore, DD is often associated with systolic dysfunction, left ventricular hypertrophy or indeed pulmonary hypertension. When the diagnosis of DD is made, peri-operative attention to this group of patients becomes mandatory.

Jugular bulb desaturation during off-pump coronary artery bypass surgery

PURPOSE

Off-pump coronary artery bypass grafting surgery (OPCAB) frequently results in significant jugular bulb desaturation. Although jugular bulb desaturation during OPCAB may be associated with postoperative cerebral injury, routine jugular bulb oximetry appears to be invasive and expensive. We hypothesized that intraoperative hemodynamic compromise during OPCAB due to cardiac displacement is associated with jugular bulb desaturation which correlates with specific hemodynamic and physiological changes.

METHODS

Hemodynamic and physiological data were measured at the following points: (1) before anastomosis of the coronary artery (baseline); (2) during anastomosis of the left anterior descending artery; (3) during anastomosis of the circumflex branch or posterior descending artery; and (4) after chest closure. Arterial, mixed venous, and jugular venous bulb blood gas analyses were performed serially.

RESULTS

Jugular bulb desaturation (<or=50%) frequently occurred during surgical displacement of the heart. Mixed venous oxygen saturation (S(VO2)), partial pressure of carbon dioxide (Pa(CO2)), and central venous pressure (CVP) showed a significant relationship with jugular bulb oxygen saturation (r = 0.45) by multivariate linear regression analysis. Multivariate logistic regression analysis also demonstrated that S(VO2) <or= 70%, Pa(CO2) <or= 40 mmHg, and CVP >or= 8 mmHg were likely predictors of the occurrence of jugular bulb desaturation.

CONCLUSION

Changes in S(VO2) and Pa(CO2) were associated with jugular bulb oxygen saturation, and S(VO2) <or= 70%, Pa(CO2) <or= 40 mmHg, and CVP >or= 8 mmHg had a significant odds ratio for jugular bulb desaturation. We suggest that achieving normal values of S(VO2), Pa(CO2) and CVP may be important to prevent cerebral desaturation during OPCAB.

Minimally invasive direct coronary artery bypass and off-pump coronary artery bypass surgery: anesthetic considerations

Many new surgical technologies are being developed, with the overall aim of improving outcomes. One common feature of many new technologies is that they offer a safer approach than previous techniques; one of the greatest forces for change over the last 30 years is risk reduction. Cardiac surgery risk has been effectively undercut by percutaneous-based procedures, which have offered dramatic reductions in risk--at least in the short term. Beating heart techniques, whether minimally invasive direct coronary artery bypass (MIDCAB), off-pump coronary artery bypass surgery (OPCAB), or in other forms, such as percutaneous valve replacement, are likely to dramatically increase over the next decade. What role OPCAB and MIDCAB techniques will play in this new era is anyone's guess.

The effect of milrinone on the right ventricular function in patients with reduced right ventricular function undergoing off-pump coronary artery bypass graft surgery

This investigation evaluated the effect of continuous milrinone infusion on right ventricular (RV) function during off-pump coronary artery bypass graft (OPCAB) surgery in patients with reduced RV function. Fifty patients scheduled for OPCAB, with thermodilution RV ejection fraction (RVEF) <35% after anesthesia induction, were randomly allocated to either milrinone (0.5 microg/kg/min) or control (saline) group. Hemodynamic variables and RV volumetric data measured by thermodilution method were collected as follows: after anesthesia induction (T1); 10 min after heart displacement for obtuse marginal artery anastomosis (T2); after pericardial closure (T3). Cardiac index and heart rate increased and systemic vascular resistance significantly decreased in milrinone group at T2. Initially lower RVEF of milrinone group was eventually comparable to control group after milrinone infusion. RVEF did not significantly change at T2 and T3 in both groups. RV end-diastolic volume in milrinone group consistently decreased from the baseline at T2 and T3. Continuous infusion of milrinone without a bolus demonstrated potentially beneficial effect on cardiac output and RV afterload in patients with reduced RV function during OPCAB. However, aggressive augmentation of intravascular volume seems to be necessary to maximize the effect of the milrinone in these patients.

Effects of on-pump versus off-pump coronary artery bypass graft surgery on right ventricular function

OBJECTIVES

Right ventricular dysfunction is a possible cause of cardiac failure after coronary surgery. The use of cardiopulmonary bypass is regarded as a major cause for its occurrence, and it has been postulated that performing coronary surgery without cardiopulmonary bypass might reduce ventricular dysfunction. Therefore, this prospective, randomized, controlled study tested the hypothesis that off-pump coronary surgery would better preserve right ventricular systolic and diastolic function than conventional bypass surgery.

METHODS

Fifty patients scheduled for elective coronary artery bypass surgery were randomly assigned to conventional or off-pump surgery. Right ventricular function was assessed by intraoperative transesophageal echocardiography immediately before and after coronary surgery. Right ventricular ejection fraction was used as a marker of global systolic function and tricuspid early/late (atrial) ratio as a marker of the global diastolic function. Peak systolic and early diastolic velocities of the lateral tricuspid annulus were studied to assess systolic and diastolic function in the area of the right ventricular free wall.

RESULTS

Surgery was completed according to randomization in 48 of 50 patients. Preoperative characteristics were similar in both groups. Intraoperative differences between the two groups included a higher volume of allogeneic blood transfusion in the conventional surgery group. At the end of surgery, global systolic right ventricular function was similarly maintained and diastolic function similarly impaired in both groups. There were no significant intergroup differences in any of the echocardiographic markers of right ventricular function.

CONCLUSIONS

Off-pump surgery did not better preserve right ventricular systolic and diastolic function than did conventional coronary surgery.