Hemodynamic changes during displacement of the beating heart by the Utrecht Octopus method

Off-pump coronary artery bypass grafting for patients with severely reduced ventricular function-A justified strategy?

BACKGROUND AND AIM

Low ejection fraction (EF) has been identified as a main risk factor for perioperative complications and mortality after coronary artery bypass grafting (CABG). The purpose of this study was to compare the efficacy and early as well as midterm outcomes of off-pump CABG (OPCAB) and conventional CABG (ONCAB) surgery in patients with reduced EF.

METHODS

We performed a retrospective review of patient demographics, preoperative risk factors, operative and postoperative outcomes of patients with left ventricular EF (LV-EF) ≤35%, who underwent CABG at our institution between January 2015 and December 2017. Propensity score and multivariate logistic regression analysis were used to compare risk adjusted outcomes between groups.

RESULTS

Overall, 111 consecutive CABG-patients with LV-EF ≤ 35% underwent either ONCAB (46 patients, 41.4%) or OPCAB surgery (65 patients, 58.6%). There was no difference in early mortality (5% vs. 7.5%, p = .64) between groups. After propensity score matching, OPCAB-patients required significantly less re-sternotomies for bleeding (20% vs. 2.5%, p = .03) and consequently received significantly less blood transfusions (57.5% vs. 32.5%, p = .03). Fewer OPCAB-patients experienced low cardiac output syndrome (22.5% vs. 42.5%, p = .06) and suffered from postoperative delirium (22.5% vs. 42.5%, p = .06). There were no differences in completeness of revascularization between groups (median 1 (1.0-1.33; 1.0-1.33) OPCAB versus median 1 (1-1.33; 0.67-2) ONCAB, p = .95). Survival after 6 months, one year and three years was similar for ONCAB- and OPCAB-patients (ONCAB 92.3%, 89.4%, and 89.4% vs. OPCAB 89.8%, 85.7%, and 82.1%; p = .403). More ONCAB-patients needed a coronary re-intervention during follow-up (8.6% vs. 2.3%, p = .402).

CONCLUSION

OPCAB-surgery is a safe and effective option for patients with reduced EF. Furthermore, it does not come at the expense of less complete revascularization or increased coronary re-intervention during early follow-up.

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.

Morphologic Evaluation of the Mitral Annulus During Displacement of the Heart in Off-Pump Coronary Artery Bypass Surgery

OBJECTIVE

To evaluate the morphologic changes of the mitral annulus using 3-dimensional transesophageal echocardiography during heart displacement to expose the anastomosis site in off-pump coronary artery bypass surgery (OPCAB).

DESIGN

Prospective case series.

SETTING

Single center, university hospital.

PARTICIPANTS

The study comprised 34 consecutive patients who underwent OPCAB of the left circumflex artery (LCX) and the right coronary artery (RCA).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Mitral annulus parameters were measured using the Mitral Valve Quantification program after sternotomy (physiologic position) and during displacement of the heart to expose the LCX (LCX position) and the RCA (RCA position). The height of the mitral annulus was significantly lower in the LCX (5.76 ± 0.90 mm) and RCA (5.92 ± 0.97 mm) positions than in the physiologic position (6.96 ± 0.99 mm; both p < 0.0001). The percent change in the height of the mitral annulus was significantly greater in the mitral regurgitation group than in the mitral regurgitation nondeterioration group when in the LCX (-16.3% ± 6.0% v -11.9% ± 3.3%, p = 0.0203) and RCA (-16.9% ± 6.3% v -12.1% ± 3.8%, p = 0.0207) positions. The anteroposterior and intercommissural diameters, annulus perimeter, and surface area of the mitral annulus did not differ significantly among all heart positions.

CONCLUSIONS

The mitral annulus flattened and lost its saddle shape without expanding while in the LCX and RCA positions. The greater percent change in the height of the mitral annulus may aggravate mitral regurgitation.

The influence of a low ejection fraction on long-term survival in systematic off-pump coronary artery bypass surgery

OBJECTIVE

Poor left-ventricular ejection fraction (EF) is a recognized operative and long-term risk factor in coronary artery bypass surgery. Over the past decade, off-pump coronary artery bypass surgery has emerged as a new strategy to address myocardial revascularization in poor left-ventricular EF patients, but few reports have documented long-term results. The aim of this study was to investigate long-term clinical results in off-pump coronary artery bypass patients with ≤ 35% left-ventricular EF.

METHODS

From September 1996 to May 2006, 1250 patients underwent off-pump coronary artery bypass revascularization, and were prospectively followed-up at the Montreal Heart Institute. Among them, 137 patients (pts) had a preoperative left-ventricular EF ≤ 35%. Follow-up was completed in 97% of patients.

RESULTS

Mean follow-up was 66 ± 34 months. Rate of grafts per pts was comparable in both groups. Overall 30-day mortality was 1.7% (1.5% EF >35% pts vs 2.9% in EF ≤ 35% pts; p = 0.19). Ten-year survival was lower in poor EF patients (44 ± 7% vs 76 ± 2%), and remained significant even after adjusting for risk factors (p = 0.04). Freedom from cardiac death for both groups was also significantly reduced in poor EF patients (p = 0.008). After adjustment, freedom from the combined end point of cardiac or sudden death, myocardial infarction, repeat coronary revascularization, unstable angina, and cardiac failure was comparable in both groups (p = 0.5).

CONCLUSIONS

Off-pump coronary artery bypass surgery can be performed adequately and safely in poor EF patients. However, overall and cardiac survival was decreased in this subset of patients with a comparable freedom from major cardiac adverse related events.

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.

Hemodynamic advantages of right heart decompression during off-pump surgery

Cardiac maneuvering during off-pump coronary artery bypass surgery can compress the right ventricle, causing temporary dysfunction and hemodynamic instability. The hemodynamic impact of a decompression technique comprising right pleurotomy and pericardial release was investigated during cardiac elevation. Intraoperative continuous real-time monitoring of cardiac index and stroke volume index was carried out using the PulseCO system in 12 consecutive patients with normal ventricular function who underwent off-pump coronary artery bypass by a single surgeon. A pulmonary artery catheter was used to monitor pulmonary artery pressure and systemic venous O(2) saturation. Hemodynamic changes during vertical displacement of the heart were measured before and after performing a right pleurotomy and pericardial release. Following right heart decompression, stroke volume index, cardiac index, mean arterial pressure, and systemic venous O(2) saturation were significantly better preserved during cardiac elevation. This demonstrates that right heart decompression via pleurotomy and pericardial release significantly improves hemodynamic stability during cardiac manipulation. We recommend the use of this procedure in off-pump coronary artery bypass when cardiac tilting is required.

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.

Off-pump versus on-pump CABG in high-risk patients: Short- and mid-term outcome

OBJECTIVE

During recent years Conventional Coronary Artery Bypass Grafting (cCABG) and Off-Pump Coronary Bypass (OPCAB) have been compared in several randomised and non-randomised studies. Focus has been on postoperative outcome with short-term follow-up in low-risk patients and therefore little is known of the effectiveness of OPCAB in high-risk patients. Furthermore, it is unknown if a potential beneficial short-term outcome is consistent over time.

DESIGN

In 2001, 217 patients with a Euroscore > or =5 were included in an observational cohort study; 162 patients were operated by cCABG and 55 by OPCAB. Follow-up data were retrieved from the Danish national person registry. The study includes a mid-term follow-up, with a mean follow-up time of 3.97 years+/-0.32.

RESULTS

No differences in mortality between OPCAB and cCABG were found. In-hospital mortality was 5.5% in the OPCAB group vs 5.6% in the cCABG group and mid-term mortality was 21.8% in the OPCAB group vs 24.7% in the cCABG group; p = 0.71. During the follow-up period 41.5% of patients with an EF < or =35% at the time of surgery and 43.3% of patients with a Euroscore >8 died. Seven percent in the cCABG group had a perioperative AMI vs none in the OPCAB group; p < 0.05. In 74.5% cCABG's allogenic transfusions of blood components was necessary vs only 55.6% OPCAB's (p < 0.05). No significant differences in CNS complications or atrial fibrillation could be demonstrated.

CONCLUSION

A similar outcome between OPCAB in cCABG in high-risk patients with respect to mortality was found. OPCAB seems to have a beneficial effect on morbidity. A cautious approach to patients with a combined high Euroscore and low ejection fraction should be the strategy of choice.

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.

Renal outcome in off-pump coronary artery bypass grafting: predictors for renal impairment with multivariate analysis

OBJECTIVE

: Recent studies on the efficacy of off-pump coronary artery bypass grafting (OPCABG) have reported encouraging results on postoperative renal function, but improvements can still be made.

METHODS

: A total of 368 patients, none needing chronic dialysis, underwent isolated OPCABG at our institution between January 1999 and March 2005. They were divided into 3 groups according to renal function as indicated by the serum creatinine levels: group N (n = 332) with normal function, group M (n = 30) with mild to moderate renal dysfunction, and group S (n = 6), with severe renal dysfunction. Creatinine ratio and early outcomes were compared among the groups. Predictors for renal impairment were determined by multiple regression analysis.

RESULTS

: In-hospital mortality rate was similar (group N, 0.6%; group M, 0%; group S, 0%). The percentage of patients with a creatinine ratio greater than 1.6 was significantly larger in group S (group N, 13%; group M, 13%; group S, 50%; P < 0.05). Postoperative hemodialysis, which was temporary, was required more frequently in group S (group N, 0.3%; group M, 3%; group S, 67%; P < 0.05). In group N, 38 patients (11%) had new renal impairment after OPCABG. Preoperative serum creatinine levels ≥2.5 mg/dL, ejection fraction <0.4, amount of blood transfusion, and more than 4 bypasses were potent predictors for postoperative renal impairment.

CONCLUSIONS

: Clinical results of OPCABG on renal function were satisfactory regardless of preoperative renal function. However, perioperative renal function should be closely monitored in patients with known risk factors, even when OPCABG is performed.

Pump-assisted beating heart surgery

Presentation of the revascularization of ischemized myocardium: beating heart technique using pump-assisted extracorporeal circulation. Main technique of revascularization is presented with highlights of modern mini extracorporeal circulation and beating heart surgery devices. Clinical physiological aspects of the method are described and bibliographical data provided.

Displacement of the Beating Heart with a Low-Profile Suction-Based Apical Positioning Device in a Closed Chest

Background

Off-pump, multivessel, endoscopic coronary artery bypass requires cardiac displacement within an intact chest. The current study evaluated right ventricular performance and systemic hemodynamics while exposing the posterior surface of the heart using a novel, low-profile, apical suction-based cardiac positioner in a closed-chest, beating-heart model.

Methods

Six pigs underwent instrumentation with continuous monitoring of arterial pressure by fluid-filled transducer and cardiac output and coronary blood flow by ultrasound transit time flow probe. Right ventricular (RV) pressure-volume loops were generated by an impedance catheter. Heart rate was maintained between 80 and 100 beats per minute pharmacologically. The cardiac positioner displaced the heart endoscopically through a port. Data were obtained in 5 sequential phases: (1) baseline/free-beating, (2) positioner coaptation, (3) addition of Trendelenburg, (4) cardiac displacement with Trendelenburg, and (5) cardiac displacement without Trendelenburg.

Results

Cardiac displacement without Trendelenburg (Phase 5) resulted in a significant (P < 0.05) decrease in cardiac output, coronary blood flow, RV systolic pressure (RVSP), mean arterial pressure, RV end-diastolic volume (RVEDV), and RV end-systolic volume (RVESV) compared with baseline (Phase 1). With Trendelenburg added to cardiac displacement (Phase 4), all parameters improved, but only RVSP, mean arterial pressure, and RVEDV were comparable to baseline (Phase 1). There were no local complications from device coaptation.

Conclusions

The low-profile endoscopic cardiac positioner is safe and effective in the closed-chest, beating-heart porcine model. Nevertheless, cardiac displacement in a closed chest does cause impairment in ventricular performance that can be ameliorated by the addition of Trendelenburg and further technological progress.

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.

Clinical Outcomes of Low-Risk Patients Undergoing Beating-Heart Surgery With or Without Pulmonary Artery Catheterization

OBJECTIVE

For patients who undergo off-pump coronary artery bypass (OPCAB) surgery, pulmonary artery catheterization (PAC) has been proposed as a useful intraoperative monitoring tool. This study was designed to determine if the choice of PAC versus central venous pressure monitoring (CVP) had any effect on outcome after OPCAB. This study compared these 2 methods of hemodynamic monitoring in low-risk patients undergoing beating-heart surgery via a median sternotomy and evaluated their effect on morbidity and in-hospital mortality.

DESIGN

Retrospective database and medical record review.

SETTING

Tertiary care teaching hospital.

PARTICIPANTS

Low-risk patients who had coronary revascularization via a median sternotomy on the beating heart.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A population of 2,414 low-risk patients who had beating-heart coronary revascularization between January 2000 and December 2003 was reviewed. Most patients (1,671 or 69.2%) received a PAC, whereas 743 (30.8%) had CVP monitoring. Risk-adjusted logistic regression analyses were performed to investigate the effect of each technique on clinical outcomes. The groups were comparable in both baseline characteristics and Parsonett's mortality risk (1.5 +/- 0.9, p = 0.58). Univariate analysis failed to show a difference in operative mortality (p = 0.76), on-pump conversion rate for completion of aortocoronary bypasses (p = 0.82), postoperative low cardiac output (p = 0.10), or prolonged inotropic agent use (p = 0.22). Similarly, in the multivariate analysis, both groups had a similar rate of conversion to an on-pump procedure for completion of coronary artery grafting (p = 0.91), intraoperative intra-aortic balloon pump use (p = 0.69), low cardiac output state (p = 0.16), or in-hospital mortality (p = 0.51).

CONCLUSIONS

This single-institution, retrospective study suggests that in low-risk patients undergoing beating-heart surgery, CVP monitoring may be sufficient.

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.

Myocardial Revascularization in Patients with Low Ejection Fraction <=35%: Effect of Pump Technique on Early Morbidity and Mortality

BACKGROUND AND AIM

Left ventricular dysfunction is an important predictor of in-hospital mortality. Surgical risk among these patients remains high. The present study is conducted to evaluate the difference in early morbidity and mortality among patients with compromised left ventricular function (LVF) after myocardial revascularization using either off-pump or on-pump coronary artery bypass graft.

METHODS

Between April 2000 and April 2004, 150 patients with ejection fraction (EF) < or =35% underwent isolated coronary artery bypass grafting. Eighty-four patients underwent conventional bypass (mean EF 30.1%+/- 4.2) and 66 patients had off-pump coronary artery bypass (mean EF 27.5%+/- 5.5). Different variables (preoperative, intraoperative, and postoperative) were evaluated and compared. Determination of operation risk was done using EuroSCORE. Patients who underwent OPCAB were more risky due to a high percentage of associated comorbidities, mean EuroSCORE was 12.96 +/- 13.21 in comparison to 8.47 +/- 10.22 in CCAB.

RESULTS

The mean operative mortality was 8.7%. Patients who underwent OPCAB had a lower operative mortality than CCAB (6.1% vs. 10.7%) inspite of a higher preoperative predicted risk score. Completeness of revascularization was higher among the CCAB group (85.7% vs. 69.7%; p = 0.01). Subsequently, the mean number of grafts was significantly higher among this group (3.4+/-0.7 vs. 2.0 +/-0.9; p < 0.001). On the other hand, morbidity was significantly higher in CCAB (35.7% vs. 19.7%; p = 0.03). However, the incidence of both myocardial infarction and atrial fibrillation was more among OPCAB.

CONCLUSIONS

Patients with left ventricular dysfunction are high-risk group. These patients can benefit from myocardial revascularization using either off-pump or conventional CABG, but both are associated with a higher mortality and morbidity than those with normal ventricle. The use of off-pump CABG resulted in better clinical outcome and mortality, but less number of grafts performed than those with conventional CABG especially in patients with lowest EF.

Elective Intraaortic Balloon Counterpulsation in High-Risk Off-Pump Coronary Artery Bypass Grafting

The beneficial effects of intraaortic balloon pump (IABP) in CABG with cardiopulmonary bypass (CPB) have been reported. However, the benefits of insertion of IABP electively in high-risk off-pump coronary artery bypass grafting (OPCAB) have not been established. Six hundred and twenty-five patients who underwent OPCAB form the study group. High-risk patients fulfilling two or more of the following: left main stem stenosis >70%, unstable angina, and poor left ventricular function, who had elective insertion of IABP preoperatively by the open technique (group I; n = 20) were compared with a similar high-risk group that did not (group II; n = 25). There were no significant differences in risk factors between the two groups (Euroscore 5.68). The mean number of grafts was similar. Postoperatively, there were no significant differences in the need for inotropes, duration of ventilation, arrhythmias, cerebrovascular, gastrointestinal, and infective complications (p = NS). There were no IABP-related complications. Acute renal failure requiring hemofiltration was higher in group II (n = 5; p < 0.05). Four patients (16%) in group II required postoperative IABP. Although intensive care stay was longer in group I (27.6 +/- 15.3 vs. 18.6 +/- 9.1 hours; p < 0.05), patients in group I were discharged earlier from hospital. There was no difference in mortality between the two groups (n = 1 in each group). In high-risk patients undergoing OPCAB, routine preoperative insertion of IABP electively reduces the incidence of acute renal failure. In addition it avoids the need for emergency insertion postoperatively and may result in earlier discharge.

Does off-pump coronary artery bypass grafting beneficially affect renal function?

BACKGROUND

Off-pump coronary artery bypass grafting (CABG) has been reported to beneficially affect renal function, but this remains to be confirmed. The purpose of the present paper was to study the effects of off-pump CABG on renal function and analyse predictors of postoperative renal impairment in patients who received off-pump CABG.

METHODS

A total of 451 patients who underwent isolated CABG between January 1999 and August 2003 were retrospectively studied. No patient was receiving dialysis. A total of 300 patients (228 men) underwent off-pump CABG (off-pump group) and 151 patients (104 men) underwent on-pump CABG (on-pump group). Perioperative serum creatinine levels and creatinine ratios (peak postoperative creatinine level/preoperative creatinine level) were compared between the groups.

RESULTS

Renal impairment (serum creatinine >1.5 mg/dL) developed postoperatively in 12.7% of the off-pump group and 18.5% of the on-pump group (P = 0.1). The creatinine ratio was significantly lower in the off-pump group (1.2 +/- 0.4) than in the on-pump group (1.4 +/- 0.7, P = 0.003). Logistic regression analysis demonstrated that the strongest predictors of postoperative renal impairment in off-pump CABG were left ventricular dysfunction (odds ratio 10.8) and multivessel grafting (odds ratio 4.3).

CONCLUSIONS

Off-pump CABG provides better renal protection than on-pump CABG. However, perioperative renal function should be closely monitored in patients who have left ventricular dysfunction or who undergo multivessel grafting, even when off-pump CABG is performed.

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.

Jugular bulb desaturation during coronary artery surgery: a comparison of off-pump and on-pump procedures † †Presented in part at the annual Outcomes Meeting at Key West, FL, USA, 2001. ‡ ‡This article is accompanied by the Editorial

BACKGROUND

Conventional coronary artery bypass surgery has been associated with cerebral injury attributed to cardiopulmonary bypass (CPB) and surgical manipulation of the ascending aorta. Off-pump coronary artery surgery avoids these factors and could prevent cerebral injury. However, moving the heart from its natural position affects the circulation and could compromise cerebral oxygenation and perfusion. We set out to compare episodes of poor global cerebral oxygenation, defined as a jugular bulb saturation less than 50%, between patients randomized to off-pump or (conventional) on-pump coronary artery surgery.

METHODS

One hundred and eighty-seven patients were assigned randomly to off-pump or on-pump coronary artery surgery. Oxygen saturation in the jugular bulb (SjO2) was measured during revascularization of the three main coronary vessels in the off-pump group, and at the start of CPB, before rewarming, and after rewarming in the on-pump group. We compared samples with jugular bulb with desaturation (SjO2) < or = 50%) between treatment groups.

RESULTS

One hundred and seventy-five patients (81 in the off-pump group [93%] and 94 in the on-pump group [94%]) had complete jugular oxygen saturation data. Thirty-nine patients in the off-pump group (48%) and 25 patients in the on-pump group (27%) had one or more samples with desaturation during revascularization or CPB (odds ratio after adjustment for other factors, 0.39; 95% confidence interval, 0.21-0.73, P<0.01).

CONCLUSION

Jugular bulb desaturation occurs more frequently during off-pump coronary artery surgery than during conventional coronary artery surgery.

Routine preoperative insertion of IABP in high-risk off-pump coronary artery bypass grafting

The beneficial effects of intraaortic balloon pump (IABP) in coronary artery bypass graft surgery with cardiopulmonary bypass have been reported. However, whether preoperative insertion of IABP in high-risk off-pump coronary artery bypass grafting (OPCAB) has any beneficial effects remains to be established. We report our experience of preoperative insertion of IABP in OPCAB.

Levosimendan in off-pump coronary artery bypass: a four-times masked controlled study

We tested the hypothesis that levosimendan produced beneficial hemodynamic effects during and after off-pump coronary artery bypass grafting in patients with good preoperative left ventricular function. Levosimendan at low dose (12 microg/kg), high dose (24 microg/kg), or placebo were administered in thirty-one patients in a randomized and four-times masked controlled study. Heart rate was not significantly different between experimental groups. Significant increases in cardiac output and left ventricular ejection fraction occurred after high-dose (P < 0.001; P = 0.006) and low-dose levosimendan (P = 0.001; P = 0.002). Both doses of levosimendan produced significant increased stroke volume and decreased systemic vascular resistance. Mean arterial pressure, pulmonary capillary wedge pressure, and left ventricular end-systolic volume were not significantly different between groups. The low-dose levosimendan produced better hemodynamic response than high-dose and may be preferable in patients undergoing off-pump coronary artery bypass grafting.

Multivessel Off-Pump Revascularization in Patients with Significant Left Main Coronary Artery Stenosis:. Early and Midterm Outcome Analysis

BACKGROUND

The presence of significant left main stenosis (> or =50%) has been considered a relative contraindication to the use of off-pump coronary artery bypass (OPCAB) stemming from well-documented hemodynamic perturbations during the displacement of the heart. We examined our experience with patients with critical left main stenosis (LMS) to assess the safety and feasibility of OPCAB in this subgroup.

METHODS

Our prospectively updated database was queried to identify all patients with severe left main disease who underwent isolated coronary revascularization between January 1, 1999 and May 31, 2002. This query yielded 234 on-pump and 420 off-pump patients with significant LMS whose clinical information was retrospectively reviewed.

RESULTS

The groups were well matched with regard to gender, left ventricular function, surgical priority, and severity of angina. The conventional coronary artery bypass (CABG) group was significantly younger than the OPCAB group and had a higher incidence of a previous myocardial infarction. Patients in the CABG cohort were more likely than OPCAB patients to remain ventilated after 24 hours, require placement of intraoperative or postoperative intraaortic balloon pump, or suffer from postoperative renal failure. There was a decrease in mortality (6.4% vs. 1.9%; p = 0.006) when CPB was eliminated. Intermediate term survival analysis revealed a significant survival benefit in the off-pump group (p = 0.007).

CONCLUSIONS

Multivessel off-pump revascularization in patients with severe left main disease is a safe and effective alternative to conventional bypass grafting and conveys a survival benefit.

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.

Hemodynamic Changes During Posterior Vessel Off-Pump Coronary Artery Bypass: Comparison Between Deep Pericardial Sutures and Vacuum-Assisted Apical Suction Device

BACKGROUND

Displacement of the heart to expose posterior vessels during off-pump coronary artery bypass may cause hemodynamic derangement. The aims of this study were (1) to elucidate the hemodynamic changes during off-pump coronary artery bypass for the obtuse marginal branch (OM) of the left circumflex artery; and (2) to compare the hemodynamic changes caused by a deep pericardial suture technique with those caused by a vacuum-assisted apical suction device for displacement of the heart.

METHODS

Hemodynamic changes during posterior vessel off-pump coronary artery bypass were studied in a prospective randomized manner. A deep pericardial suture technique (group 1, n = 10) or a vacuum-assisted apical suction device (group 2, n = 10) was used to facilitate the exposure of the OM. Hemodynamic variables such as cardiac index, stroke volume index (SVI), mean arterial pressure, mean pulmonary artery pressure, central venous pressure, pulmonary capillary wedge pressure, heart rate, systemic vascular resistance, pulmonary vascular resistance, left ventricular stroke work index, and right ventricular stroke work index were monitored during off-pump coronary artery bypass. Hemodynamic data were obtained before revascularization of the left anterior descending coronary artery at a baseline (T0), 3 minutes after heart displacement for revascularization of OM (T1), 3 minutes after the beginning of OM grafting (T2), and 3 minutes after the completion of OM grafting and heart repositioning (T3).

RESULTS

There were no significant differences in the baseline hemodynamic variables (T0) between the two groups. In group 1, SVI, cardiac index, left ventricular stroke work index, and right ventricular stroke work index decreased significantly, and central venous pressure and pulmonary capillary wedge pressure increased significantly, during displacement of the heart (T1, p < 0.05). In group 2, SVI decreased significantly, and central venous pressure, pulmonary capillary wedge pressure, and mean pulmonary artery pressure increased significantly during displacement of the heart (T1, p < 0.05). The percent changes of cardiac index, SVI, and right ventricular stroke work index during OM grafting (T2) in comparison with baseline values (T0) were significantly larger in group 1 than in group 2 (cardiac index, 73% +/- 12% versus 90% +/- 11%; SVI, 69% +/- 12% versus 86% +/- 8%; right ventricular stroke work index, 30% +/- 17% versus 71% +/- 25%, in groups 1 versus 2, respectively; p < 0.05).

CONCLUSIONS

Displacement of the heart using either a deep pericardial suture technique or a vacuum-assisted apical suction device caused a significant decrease in SVI. The hemodynamic changes during OM grafting were smaller when using a vacuum-assisted apical suction device.

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.

Haemodynamic effects of a milrinone infusion without a bolus in patients undergoing off-pump coronary artery bypass graft surgery

The haemodynamic effects of a continuous infusion of milrinone without an initial bolus dose were evaluated in patients undergoing off-pump coronary artery bypass graft surgery. After internal mammary artery harvest, milrinone 0.5 microg.min(-1).kg(-1) (29 patients) or a normal saline infusion (33 patients) was started and continued until all graft anastomoses were completed. Haemodynamic variables were recorded before application of the tissue stabiliser, at 1, 3, 5 and 10 min after the application of the stabiliser, and after its removal. The administration of a milrinone infusion was associated with a smaller decrease in cardiac output and mixed venous oxygen saturation during all the coronary artery anastomoses, with no severe complications and a decreased dose of norepinephrine infused to maintain systemic arterial pressure.

Deep pericardial stitch enables hemodynamically stable exposure of beating heart

The use of a deep pericardial stitch to obtain optimal exposure for precise distal anastomoses was assessed in 51 patients (mean age, 56.5 +/- 9.1 years) undergoing off-pump coronary artery bypass grafting. Hemodynamic data were recorded after sternotomy, before, and after each of the 120 distal anastomosis. Most hemodynamic parameters did not change throughout the procedures. During exposure of the circumflex artery, there were significant decreases in systolic arterial pressure from 106.0 +/- 15.5 to 87.7 +/- 13.6 mm Hg, mean systemic arterial pressure from 83.9 +/- 11.7 to 68.5 +/- 17.0 mm Hg, stroke volume from 68.5 +/- 23.3 to 50.5 +/- 18.3 mL, and stroke index from 34.4 +/- 11.5 to 24.3 +/- 8.7 mL x m(-2). Cardiac function was not affected when other coronary arteries were bypassed. On completion of all anastomoses, hemodynamics returned to baseline status. It was concluded that the deep pericardial stitch enabled stable and safe exposure of the heart for off-pump coronary artery grafting.

A prospective evaluation of hemodynamic instability during off-pump coronary artery bypass surgery

OBJECTIVE

Despite recognized hemodynamic derangements during cardiac displacement, most patients appear to tolerate the off-pump procedure well. However, some patients unpredictably become hemodynamically unstable requiring emergency cardiopulmonary bypass or intra-aortic balloon pump support. After an experience of 5306 multivessel off-pump coronary artery bypasses (OPCABs), this study was undertaken to determine the factors that would identify the patients who were at a higher risk for the procedure.

DESIGN

Prospective clinical investigation.

SETTING

Tertiary care academic cardiac care center.

PARTICIPANTS

Five hundred consecutive patients undergoing multivessel OPCAB from September to December 2001.

INTERVENTIONS

Various cardiac and extracardiac factors were charted in prespecified data-entry forms. Multiple logistic regression analysis was done to determine if any identifiable factors were predictors of a higher risk of unacceptable hemodynamic instability during OPCAB. Institution of IABP support or conversion to CPB were the endpoints of the study.

MEASUREMENTS AND MAIN RESULTS

Of the 500 patients studied, significant hemodynamic instability developed in 24 (4.8%) patients. IABP support was instituted in 16 (3.2%) patients, and 8 (1.6%) were converted to CPB. Stepwise logistic regression identified ejection fraction <25% (p < 0.001), myocardial infarction of <1-month duration (p = 0.009), congestive heart failure (p = 0.016), and preoperative hemodynamic instability (p = 0.057) as predictors of conversion during OPCAB.

CONCLUSIONS

Patients with low left ventricular ejection fraction <25%, myocardial infarction of <1-month duration, congestive heart failure, or preoperative hemodynamic instability constitute the high-risk group for OPCAB.

Right pleuropericardial release: a useful technique in off-pump coronary surgery

We describe the use of right pleurotomy combined with right pericardial release during off-pump coronary surgery. The maneuver releases the compression exerted on the right cardiac chambers during cardiac verticalization and improves hemodynamic stability during exposure of the posterior or lateral coronary vessels.

Perfusion-assisted direct coronary artery bypass provides early reperfusion of ischemic myocardium and facilitates complete revascularization

BACKGROUND

Perfusion-assisted direct coronary artery bypass (PADCAB) was developed to initiate early reperfusion of grafted coronary artery segments during off-pump operations to resolve episodes of myocardial ischemia and avoid its sequelae. This case series outlines intraoperative findings and clinical outcomes of our first year clinical experience with PADCAB.

METHODS

From November 1999 to November 2000, 169 PADCAB and 358 off-pump coronary artery bypass procedures were performed at the Emory University Hospitals. The decision to use PADCAB was predicated on surgeon preference. Perfusion pressure and flow, amount of intracoronary nitroglycerin, and total perfusion time and volume were recorded at the time of operation.

RESULTS

One off-pump coronary artery bypass patient required emergent conversion to cardiopulmonary bypass. Two PADCAB patients had ischemic ventricular arrhythmias during target vessel occlusion that resolved once active perfusion had begun. Perfusion pressure in PADCAB grafts was on average 44% higher than mean arterial pressure (p < 0.001). Nitroglycerin, infused locally by PADCAB, was used in 67 patients to resolve ischemic episodes and increase initial coronary flows. The mean number of diseased coronary territories and grafts placed was 2.8 +/- 0.5 and 3.4 +/- 0.7, respectively, in the PADCAB group, and 2.3 +/- 0.8 and 2.7 +/- 1.0, respectively, in the off-pump coronary artery bypass group (p < 0.001 for both comparisons). More PADCAB patients received lateral wall grafts than off-pump coronary artery bypass patients (83.4% vs 59.4%; p < 0.001). Hospital death and postoperative myocardial infarction were not different between groups.

CONCLUSIONS

PADCAB can provide suprasystemic perfusion pressures and a means to add vasoactive drugs to target coronary vessels. PADCAB provides early reperfusion of ischemic myocardium and facilitates complete revascularization of severe multivessel coronary artery disease.

Maintaining hemodynamic stability and myocardial performance during off-pump coronary bypass surgery

Patients presenting for coronary artery bypass (CAB) surgery are now older and have more comorbid conditions. Off-pump (OPCAB) methods may reduce morbidity and mortality in these higher risk patients. Multivessel surgery has been limited by the difficulty in maintaining hemodynamic stability during lateral wall vessel grafting. Techniques for providing safe access to lateral wall vessels were applied in a largely unselected group of 665 OPCAB patients with emphasis on the avoidance of right ventricular compression. Safe access to essentially all target coronary arteries was achieved with very little need for pharmacological or mechanical support. No patient required new intraaortic balloon pumping and no patient required urgent conversion to cardiopulmonary bypass. Access to essentially all target coronary arteries can be achieved and myocardial performance can be maintained when strict attention is paid to operative strategies designed to minimize right-side heart compression.

Current trends and technique in OPCAB surgery

BACKGROUND AND AIM OF THE STUDY

Aging of the population, increased surgical risk, and technical improvement have contributed to the recent revival of off pump coronary artery bypass surgery (OPCAB). We present our experience with the systematic use of this technique.

METHODS

Between September 1996 and June 2000, 500 OPCAB procedures were performed at the Montreal Heart Institute (95% of all procedures during time frame, single surgeon). Contraindications were unstable hemodynamics, intramyocardial left anterior descending artery, and reoperation with extensive adhesions. Stabilization was achieved with pericardial sutures and mechanical compression. Surgical strategy was to first bypass the culprit lesion. Anesthetic management consisted of adequate fluid loading and minimal use of alpha-agonist. This cohort was compared to a contemporary cohort of 1,444 patients operated with cardiopulmonary bypass (CPB).

RESULTS

Demographics and risk factors were comparable for all. OPCAB patients received more grafts (3.1 +/- 0.9 vs 2.9 +/- 0.7, p = 0.006), conversion rate was low (0.4%), and complete revascularization was achieved in 93%. Operative mortality and perioperative myocardial infarction were comparable in both groups. Transfusion need, CK-MB count, postoperative use of intra-aortic balloon pump, and creatinine increase were less significant in OPCAB. Postoperative hemorrhage, atrial fibrillation, prevalence of cerebrovascular accident, and hospital stay were comparable for both groups. These results are comparable to those currently reported in the literature.

CONCLUSION

OPCAB surgery in the current era has established its safety and short-term efficacy although long-term clinical results are still warranted. Considering the changing pattern in surgical practice, OPCAB surgery should remain a therapeutic option in modern cardiac surgery.

Anesthesia for off-pump coronary artery bypass grafting

Off-pump coronary artery bypass presents special challenges for the anesthesiologist and surgeon, who must work closely together to provide optimal care. Displacement and immobilization of the heart for exposure of the coronary arteries, as well as occlusion of these vessels, can result in periods of significant hemodynamic instability. Appropriate preparation, guided therapy, and technical maneuvers can lessen such adverse hemodynamic impact. It is important for anesthesiologists to be aware of the special problems associated with this surgery, as well as the different therapies and maneuvers that can be useful in providing the best possible care. As surgeons develop greater expertise and better devices for the management of these patients, the number of coronary revascularizations without CPB is likely to increase.

Effect of off-pump coronary surgery with right ventricular assist device on organ function and inflammatory response: a randomized controlled trial

BACKGROUND

Right ventricular assist devices (RVADs) have been proposed to improve exposure of the coronary arteries in off-pump surgery. In this study we investigated the impact of the A-Med RVAD on inflammatory response and organ function in patients undergoing coronary artery bypass grafting.

METHODS

Sixty patients were prospectively randomized to conventional surgery with cardiopulmonary bypass (CPB) and cardioplegic arrest, beating heart surgery (off-pump), or beating heart surgery with the RVAD. Serial blood samples were collected postoperatively, for analysis of inflammatory markers, troponin I, protein S100, and free hemoglobin. Renal tubular function was assessed by measuring urine N-acetyl-glucosaminidase activity.

RESULTS

No hospital deaths or major postoperative complications occurred in the study population. Interleukin-6, interleukin-8, C3a, and troponin I levels after surgery were significantly higher in the CPB group compared with the off-pump and RVAD groups. Free hemoglobin levels immediately after the operation, peak and total S100 levels, and N-acetyl-glucosaminidase activity were also significantly higher in the CPB group.

CONCLUSIONS

Off-pump coronary revascularization, with or without RVAD, reduces inflammatory response, myocardial, neurologic, and renal injury, and decreases hemolysis when compared with conventional surgery with CPB and cardioplegic arrest.

Hemodynamic changes during displacement of the beating heart using epicardial stabilization for off-pump coronary artery bypass graft surgery

OBJECTIVE

To evaluate the hemodynamic alterations during off-pump coronary artery bypass graft surgery to determine the degree of impairment caused and the techniques to rectify them.

DESIGN

Prospective, observational cohort study performed from January 2000 through September 2000.

PARTICIPANTS

Patients (n = 500) with coronary artery disease undergoing multivessel off-pump coronary artery bypass graft surgery using the Octopus tissue stabilizer (Medtronic, Inc, Minneapolis, MN). Unstable patients with ongoing ischemia were excluded from the study.

INTERVENTIONS

All patients were monitored with radial artery and pulmonary artery catheters and continuous transesophageal echocardiography monitoring with a multiplane transducer. The perioperative requirement of an intracoronary shunt, inotropes, or an intra-aortic balloon pump was noted. The effect of the Trendelenburg position and fluids on hemodynamics was observed. The need for defibrillation and institution of emergency cardiopulmonary bypass were major endpoints to determine the inability of the patient to tolerate displacement of the heart.

MEASUREMENTS AND MAIN RESULTS

Mean patient age was 59.3 +/- 11.6 years. There were 204 (40%) patients in the high-risk category; 54 (10.8%) patients had left ventricular ejection fraction <25%. The mean number of grafts was 2.7 +/- 0.8. Vertical displacement of the heart to access the lateral and inferior walls decreased the mean arterial pressure by 18 +/- 4% (p < 0.01), with a concomitant increase in central venous pressure of 66 +/- 18% (p < 0.001). The stroke volume and the cardiac index were reduced by 35.7 +/- 11% (p < 0.001) and 45 +/- 13% (p < 0.001). On transesophageal echocardiography, there was development of new regional wall motion abnormalities in 59.2% and a decrease in global left ventricular functions in 61.2%. The use of inotropes was highest during anastomosis on the posterior wall-78.4% compared with 21.9% for the anterior wall. An intra-aortic balloon pump was used in 55 (11.2%) patients, and 7 (0.71 %) patients had to be put on emergency CPB. The in-hospital mortality was 1.2%.

CONCLUSION

Most patients had hemodynamic changes easily correctable by fluids and inotropes. Monitoring of left ventricular and right ventricular function by transesophageal echocardiography enhances safety of the procedure and is recommended. The use of the Octopus II tissue stabilizer proved to be a safe and versatile means to stabilize the heart during off-pump coronary artery bypass procedures, especially in high-risk patients.

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.