Systematic off-pump coronary artery revascularization: experience of 275 cases

Total ischemic time and age as predictors of PCI failure in STEMIs: A systematic review

BACKGROUND

When feasible, primary percutaneous coronary intervention (PCI) is the definitive intervention for ST-elevation myocardial infarction (STEMI). However, cardiac tissue reperfusion is not always achievable after opening the infarct-related artery. Studies have investigated associating factors and scoring for the "no-reflow" phenomenon. This paper aims to systematically establish the predictive values of total ischemic time and patient age as factors of coronary no-reflow in patients undergoing primary PCI.

METHODS

A systematic search was performed using EBSCOhost, including CINAHL Complete, Academic Search Premier, MEDLINE with Full Text, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews. Search results were compiled utilizing Zotero reference manager and exported to Covidence.org for screening, selection, and data extraction by two independent reviewers. The Newcastle-Ottawa Quality Assessment Scale for Cohort Studies was used to evaluate the eight selected studies.

RESULTS

The initial search resulted in 367 articles, with eight meeting the inclusion criteria with a total of 7060 participants. Our systematic review demonstrated that for patients older than 60 years, the odds of the no-reflow phenomenon increased 1.53- 2.53 times. Additionally, patients with increased total ischemic time had 1.147- 4.655 times the odds of no-reflow incidence.

CONCLUSIONS

Patients older than 60 years with a total ischemic time >4-6 h are at higher risk of PCI failure due to the no-reflow phenomenon. Therefore, new guidelines and more research to prevent and treat this physiologic occurrence are essential to improve coronary reperfusion after primary PCI.

Iatrogenic Aortic Dissection Associated With Cardiac Surgery: A Narrative Review

Iatrogenic aortic dissection (iAD) is a relatively rare but a life-threatening complication associated with cardiac surgery. All members of the team caring for cardiac surgical patients (surgeons, perfusionists, and anesthesiologists) must be familiar with this complication to minimize its incidence and improve outcome. The present narrative review focuses on iAD occurring intraoperatively and during the early postoperative period (within 1 month) of cardiac surgery. The review also addresses iAD that occurs late (beyond 1 month) after cardiac surgery and iAD associated with other procedures. iAD occurs in about 0.06% of cases when the ascending aorta is the site of arterial cannulation, in about 0.6% when the femoral or iliac arteries are used, and in about 0.5% when the axillary or subclavian arteries are used. Mortality is estimated to be 30% but is more than double if not recognized until the postoperative period. Site of origin of dissection is most commonly the arterial inflow cannula (∼33%). Other common sites are the aortic cross-clamp or partial occlusion clamp (∼29%) and the proximal saphenous vein anastomosis site (14%). Sixty percent of cases occur during coronary artery bypass graft (CABG) surgery and 17% during aortic valve surgery with or without CABG. iAD may be somewhat less common in off-pump versus on-pump CABG but is still not very rare. Risk factors, presentation, diagnosis, and management are reviewed in detail as is the key role of the use of echocardiography in the early diagnosis of iAD and for guiding its management.

Off-Pump Surgery: A Choice in Unstable Angina

The benefit and safety of off-pump coronary artery bypass surgery in patients with unstable angina was assessed retrospectively. From February 1996 to October 2001, 5,306 patients underwent multivessel off-pump coronary artery bypass, of whom 920 (17%) had unstable angina. In these 920 patients, ejection fractions ranged from 15% to 70%, 203 (22%) had an ejection fraction of 20%–35%, and 11 (1%) had an ejection fraction < 20%. Triple-vessel disease was present in 625 patients. Preoperative intraaortic balloon pump support was used in 28 patients. Operative approaches included mid sternotomy (86%), lower partial sternotomy (9%), and left anterior thoracotomy (2%). The number of grafts ranged from 1 to 5 with a mean of 2.43 ± 0.86, and 92.3% of patients received a left internal mammary artery graft. Twenty-two patients need intraoperative intraaortic balloon pumping. Ten patients (1%) suffered perioperative myocardial infarction. The mean hospital stay was 7.8 ± 4.3 days. Hospital mortality was 2/920 (0.22%). Intraaortic balloon pumping was helpful in these cases of unstable angina refractory to medical therapy. Off-pump coronary artery surgery was found to be safe and beneficial in these patients.

Evolution of Off-Pump Coronary Artery Bypass Grafting over 15 Years: A Single-Institution Experience of 14,030 Cases

BACKGROUND

: Off-pump coronary artery bypass grafting for multivessel disease is an important alternative to conventional myocardial revascularization using cardiopulmonary bypass. The development of exposure and stabilization techniques has made this surgery simple, safe, and routine. Experience with the technique, its evolution, the learning curve, and the pitfalls is presented.

METHODS

: A retrospective analysis was made of 28,216 patients who underwent elective coronary artery bypass grafting over a 15-year period from January 1990 through December 2004. Isolated off-pump coronary artery bypass grafting was performed in 14,030 patients and on-pump coronary artery bypass grafting in 14,186 patients. The overall period was divided into 3 groups of 5 years each: group I (1990-1994), group II (1995-1999), and group III (2000-2004). Initially, off-pump coronary artery bypass grafting was performed selectively in high-risk patients (eg, atheromatous aorta, severe systemic impairment, chronic obstructive pulmonary disease, octogenarian). Recently (2000-2004), multivessel off-pump coronary artery bypass grafting has been performed electively in 96% to 98% of patients undergoing coronary artery bypass grafting. Patients' medical charts were reviewed for age, preoperative risk factors, operative findings, intraoperative conversion rate to cardiopulmonary bypass, postoperative complications, and length of hospital stay.

RESULTS

: In the years 1990-1994 (group I), mostly high-risk cases and cases with left anterior descending coronary artery lesions were included for off-pump coronary artery surgery. In the years 1995-1999 (group II), patients with double and triple vessel disease presenting for coronary artery bypass surgery were accepted for off-pump surgery irrespective of preoperative risk factors. However, in the years 2000-2004 (group III), off-pump coronary artery bypass surgery was the first choice of approach for any patient presenting for coronary artery bypass surgery. The mean number of grafts was lower in off-pump cases than in on-pump cases in group I (2.0 ± 0.4 vs. 3.2 ± 0.80) and group II (2.6 ± 0.6 vs. 3.3 ± 0.4), whereas the mean number of grafts was higher in off-pump cases than in on-pump cases in group III (3.5 ± 0.2 vs. 3.4 ± 0.8). In groups I and II, the conversion to cardiopulmonary bypass was 5.2% and 5.9%, respectively. The conversion to cardiopulmonary bypass decreased to 1.7% in group III, which was statistically significant. Perioperative myocardial infarction was 5.2% in group I, 1.7% in group II, and 1.5% in group III. The difference between groups II and III was not statistically significant. Hospital mortality was higher in group I (5.2%) than in group II (1.2%) or III (1.1%). The difference between groups II and III was not statistically significant. Length of intensive care unit stay was 36 ± 8 hours in group I, 28 ± 7 hours in group II, and 20 ± 8 hours in group III. These differences were statistically significant. Length of postoperative hospital stay was 8 ± 2 days in group I, 7 ± 2 days in group II, and 5 ± 2 days in group III These differences were statistically significant.

CONCLUSIONS

: As surgeons' experience matures, off-pump coronary artery bypass surgery permits total myocardial revascularization in virtually all patients with multivessel coronary artery disease. Despite a significant learning curve, evolution to routine off-pump coronary artery bypass with good patient outcomes can be achieved with careful patient selection during the "learning curve." The method is safe and reproducible, and patients benefit with shorter intensive care unit and hospital stays.

Activation of coagulation and fibrinolysis during coronary artery bypass grafting: a comparison between on-pump and off-pump techniques

Coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) is associated with intense activation of hemostatic mechanisms. But the precise knowledge of the effects of eliminating CPB in patients undergoing off-pump coronary artery bypass grafting (CABG) are not well established. The present study was carried out to compare and document the changes in selected coagulation and fibrinolysis variables in patients undergoing on-pump and off-pump CABG (OPCAB). A total of 42 patients of on-pump and 31 patients of off-pump CABG were selected for the study. Platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), Fibrinogen and D-dimer levels were measured immediately, 24 h and 7 days after operation and compared with the baseline preoperative values. Statistical analysis was done by mixed ANOVA for repeated measures and Post-hoc tests using the Bonferroni correction, Chi square and unpaired t test. All the parameters were significantly changed (P < 0.05) with the time. Platelet counts, fibrinogen and D-dimer levels were significantly different between on-pump and off-pump CABG patients on immediate and 24 h postoperative period and attained almost same level after 7 days of operation. Fibrinogen level and platelet counts were increased after a sharp fall in the immediate post-operative period whereas D-dimer levels were persistently increased with a sharp peak of rise in the immediate post-operative period in on-pump group. On-pump surgery was associated with excessive fibrinolytic activity immediately after operation. The off-pump group demonstrated less activation of coagulation and fibrinolysis and delayed postoperative response that became almost equal to the on-pump group in the later postoperative period.

Impact of off-pump coronary artery bypass surgery on graft patency: current best available evidence

For more than three decades cardiac surgeons have been used to perform delicate coronary anastomoses on cardiopulmonary bypass (CPB). However, the price of a still and bloodless field is ultimately paid by the patients in the form of sequelae of negative effects of CPB including blood trauma, activation of a series of inflammatory responses, nonpulsatile flow, and possible embolization of air or debris. In an attempt to avoid these deleterious effects of CPB, off-pump coronary artery bypass surgery (OPCAB) has been rediscovered and refined. Although abundant evidence is available to suggest that excellent results can be achieved when CPB is avoided, concerns have been raised about quality of anastomosis and graft patency rates after OPCAB surgery. We are currently practicing in an era of evidence-based medicine that mandates the prospective randomized controlled trial (RCT) as the most accurate tool for determining a treatment benefit compared with a control population. This review article attempts to evaluate the current best available evidence from RCTs on the impact of OPCAB surgery on graft patency.

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.

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.

Resource utilization in on- and off-pump coronary artery surgery: Factors influencing postoperative length of stay—an experience of 1,746 consecutive patients undergoing fast-track cardiac anesthesia

OBJECTIVE

The purpose of the present investigation was to examine factors influencing resource utilization in patients undergoing on-pump coronary artery bypass graft and off-pump coronary artery bypass (OPCAB) graft surgery at a major university hospital. The resources examined were time to extubation, packed red blood cell (PRBC) transfusion, intensive care length of stay (ICULOS), preoperative and postoperative length of stay (PLOS), and total length of stay (LOS).

DESIGN

Observational study of consecutive patients undergoing on- and off-pump coronary artery bypass surgery.

SETTING

Tertiary care cardiac referral center.

PARTICIPANTS

One thousand seven hundred forty-six consecutive male and female patients undergoing primary coronary artery bypass graft (CABG) surgery over a period of 3 years (1999-2001). Eight hundred eighty-one patients underwent CABG with pump, and 865 patients underwent off-pump coronary artery bypass (OPCAB) surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The mean time to extubation after surgery was 7.4 hours for on-pump patients and 5.8 hours for the OPCAB group (p<or=0.001); 73.7% of patients on pump received PRBC transfusion as compared with 48.6% of the OPCAB group (p<or=0.001). The mean ICULOS for the on-pump group was 1.6 days and 1.4 days for the OPCAB group (p=0.006). PLOS was 6.5 days for the on-pump group and 5.6 days for the OPCAB group (p<or=0.001). Mean total LOS was 9.7 days for the on-pump group and 8.8 days for the OPCAB group (p<or=0.001). PLOS is correlated with several clinical and demographic ariables. Linear and logistic regression models were used to assess the effects of on/off pump on PLOS. Use of pump is significantly correlated with increased PLOS (p<or=0.001, Kendalls correlation), and pump use is strongly associated with transfusion (odds ratio=2.95, p<or=0.001), which in turn is a determinant of PLOS. There were no significant differences between the on- and off-pump groups in the incidence of postoperative complications except for bleeding requiring reexploration and ventilatory support for more than 72 hours. Incidence of bleeding was 3.3% in the on-pump group and 1.7% in the OPCAB group (p=0.038). In the on-pump group, 3% of patients required >72 hours to postoperative tracheal extubation compared with 1.5% in the OPCAB group (p=0.041). Hospital mortality was 2.7% for the on-pump group and 1.0% for the OPCAB group (p=0.010).

CONCLUSION

The authors found that patients undergoing on-pump CABG have significantly longer time to tracheal extubation, increased blood use, longer ICULOS, PLOS, and total LOS and higher in-hospital mortality, which would translate into significant differences in the expenses associated with these 2 surgical approaches to coronary surgery.

Visualization of intramuscular left anterior descending coronary arteries during off-pump bypass surgery

In off-pump coronary artery bypass surgery, an appropriate method for intraoperative evaluation of grafts and vessels has been awaited. We report the usefulness of a 15-MHz linear transducer for this purpose. A 15-MHz linear transducer with a SONOS 5500 (Philips Medical Systems, Best, Netherlands) was applied epicardially in off-pump coronary artery bypass surgery patients. Vascular anatomy was easily discerned when the transducer was applied in an appropriate way. In 6 patients, intramuscular coronary arteries were easily detected, and in all of these patients, anastomoses were successful. The shapes of the anastomoses were very clearly shown, and the flow and its phase in the bypass graft or coronary artery were measured with synchronization of electrocardiograms in all patients. The total left internal thoracic artery (LITA) flow (28.4 +/- 6.8 mL/s) and the pattern of the flow was dominantly diastolic in all patients. The 15-MHz linear transducer system (Philips) is very useful for detecting intramuscular left anterior descending coronary arteries and may become one of the standard tools for intraoperative evaluation in off-pump coronary artery bypass surgery.

Blood Use in Patients Undergoing Coronary Artery Bypass Surgery: Impact Of Cardiopulmonary Bypass Pump, Hematocrit, Gender, Age, and Body Weight

We investigated the impact of cardiopulmonary bypass pump (CPB), hematocrit, gender, age, and body weight on blood use in patients undergoing coronary artery bypass graft surgery at a major university hospital. Participants were 1235 consecutive patients undergoing primary coronary artery surgery over a period of 2 yr (1999 and 2000); 681 patients underwent coronary surgery with use of CPB, and 554 patients underwent off-pump coronary artery bypass surgery using a median sternotomy incision. There were 881 males and 354 females. Average packed red blood cells (PRBC) transfusion for patients on CPB was 3.4 U compared with 1.6 U for the off-pump group (P = <0.001). Patients on CPB received more frequent PRBC transfusion (72.5%) compared with 45.7% of off-pump patients (P = <0.001). Average PRBC transfusion for males was 2.2 U compared with 3.6 U for females (P = <0.001). A lower percentage of males (52.6%) than females (79.4%) received transfusion (P = <0.001). The impact of CPB, off-pump status, preoperative hematocrit <35%, gender, age >or=65 yr, and weight <or=83 kilograms using median values as cut points, on blood use was examined using logistic regression models. Use of CPB, preoperative hematocrit, (<35%) female gender, increasing age, and decreased body weight were significant predictors of transfusion (P = <0.001). Preoperative hematocrit <35% and use of CPB were the strongest predictors of PRBC transfusion.

IMPLICATIONS

We examined the impact of cardiopulmonary bypass, preoperative hematocrit, gender, age, and body weight on blood use in patients undergoing primary coronary artery bypass surgery at a tertiary care institution. We found that all five of these variables are significant predictors of blood use in patients undergoing coronary artery bypass surgery.

A comparison of bleeding and transfusion in patients who undergo coronary artery bypass grafting via sternotomy with and without cardiopulmonary bypass

OBJECTIVE

To determine whether there is a difference between on-pump cardiopulmonary bypass (CABG) and off-pump coronary artery bypass grafting (OPCAB) without heparin reversal with regard to bleeding, transfusion requirements, and incidence of surgical re-exploration of the mediastinum.

DESIGN

Retrospective chart review.

SETTING

A large academic medical center.

PARTICIPANTS

Two hundred adult patients undergoing cardiac surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred CABG patients were compared with 100 OPCAB patients. Statistical significance was measured with P values of <or=0.05. The heparin was not reversed in the OPCAB patients. CABG patients received more intraoperative allogeneic red blood cells (median 250 mL v 0 mL, p = 0.002), intraoperative autotransfusion (IAT) (550 mL v 425 mL, p = 0.001), platelets (9% v 1%, p = 0.009), and less albumin (0 mL v 250 mL, p = 0.001) than OPCAB patients. Postoperatively, CABG patients were more likely to receive fresh-frozen plasma (19% v 8%, p = 0.03) and less likely to receive IAT than the OPCAB group. During the initial 4-hour postoperative period, OPCAB patients exhibited greater blood loss via chest tube (290 mL v 385 mL, p = 0.003); however, at 12 hours and 24 hours postoperatively, there was no statistical difference in blood loss between the 2 groups. There were no statistically significant differences in surgical re-exploration of the mediastinum between the CABG and OPCAB groups.

CONCLUSION

Despite not reversing the heparin at the end of the OPCAB surgery, OPCAB surgery was associated with an overall reduction in allogeneic transfusion requirements.

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.

Heparin versus danaparoid in off-pump coronary bypass grafting: results of a prospective randomized clinical trial

OBJECTIVE

The incidence of heparin-induced thrombocytopenia is increasing, and the thrombin inhibitor danaparoid could be a useful alternative. The objective of the present study was to compare danaparoid and heparin in patients undergoing off-pump coronary artery bypass grafting.

METHODS

In a prospective, randomized, double-blind clinical trial comparing heparin (bolus of 1 mg/kg) with danaparoid (bolus of 40 U/kg), 71 patients underwent off-pump coronary artery bypass grafting with one of the study drugs. The amount of blood lost, the number of homologous blood products transfused, the troponin T levels, and the amount of anti-Xa activity were monitored.

RESULTS

Thirty-four patients underwent 2.6 +/- 0.7 bypasses with danaparoid, and 37 patients underwent 2.5 +/- 0.9 grafts with heparin (P =.8). Postoperative blood losses averaged 1394 +/- 1033 mL in patients receiving danaparoid and 1130 +/- 868 mL in patients receiving heparin (P =.2). The number of homologous blood products transfused averaged 3.6 +/- 7 units in patients receiving danaparoid and 1.9 +/- 4.4 units in patients receiving heparin (P =.2). The number of patients requiring homologous blood transfusion was higher in patients receiving danaparoid (18/34 [53%]) than in patients receiving heparin (10/37 [27%], P =.03). Serum anti-Xa activity averaged 1.6 +/- 0.6 U/mL in patients receiving danaparoid and 1.9 +/- 0.8 U/mL in patients receiving heparin 30 minutes after injection of the drugs (P =.1) and 0.3 +/- 0.1 and 0.04 +/- 0.08 U/mL, respectively, 12 hours after coronary artery bypass grafting (P =.001). Troponin serum levels were similar 48 hours after coronary artery bypass grafting (0.5 +/- 0.6 and 0.4 +/- 0.6 microg/L, respectively).

CONCLUSION

Although off-pump coronary artery bypass grafting with danaparoid versus heparin increases the number of patients exposed to homologous blood transfusion (relative risk, 2; 95% confidence limits, 1-4), off-pump coronary artery bypass grafting with danaparoid is a valuable alternative to heparin in patients with thrombocytopenia requiring surgical intervention.

Off-pump total arterial myocardial revascularization according to the right Y-graft configuration

OBJECTIVES

The aims of this study were as follows: 1) to evaluate the early outcome of the off-pump total arterial myocardial revascularization according to the right y-graft (lambda-graft) configuration and 2) to compare baseline flow and maximum flow between patients undergoing on-pump and off-pump right y-graft (RYG) construction.

METHODS

Between December 1998 and January 2001, 47 patients (Group I) and 20 patients (Group II) with three vessel disease underwent on-pump and off-pump coronary artery bypass graft (CABG) respectively according to the RYG configuration. The mean age was 55.5 +/- 4.7 years and 55 +/- 6.4 years in Groups I and II, respectively. The RYG was constructed employing both internal mammary arteries (IMAs) only, in 21 and 8 patients in Groups I and II, respectively, presenting proximal-middle third stenosis of the left anterior descending artery (LAD) and right coronary artery (RCA). The modified RYG configuration employing both IMAs and radial artery (RA) was performed in 26 and 12 patients in Groups I and II, respectively, presenting middle-distal third stenosis of the LAD and distal stenosis of the RCA or posterior descending artery stenosis. Postoperatively all patients underwent transthoracic echo color-Doppler (TTECD) contrast enhanced (by Levovist) before and after adenosine provocative testat one week and three months after operation.

RESULTS

There were no hospital deaths. The mean mechanical ventilation was significantly different in Group I versus Group II patients, 18 +/- 4.4 hours versus 13 +/- 5.7 hours, respectively (p = 0.041). The mean intensive care unit stay was 1.5 +/- 0.6 days in Group I and 1 +/- 0.4 days in Group II (p = 0.033). There were no differences between Groups I and II regarding the IMA diameter, mean velocity, and mean flow. At follow-up time, 6 +/- 2.4 months after the surgical procedure, all patients were alive and free of angina. The coronary flow reserve (CFR) at LIMA main stem was significantly higher at three months when compared to the values at one week after the surgical procedure within the same group, (LIMA)CFR (three months) = 2.37 +/- 0.6 versus (LIMA)CFR (one week) = 2.07 +/- 0.4 (p = 0.005) in Group I and (LIMA)CFR (three months) = 2.4 +/- 0.4 versus (LIMA)CFR (one week) = 2.06 +/- 0.3 (p = 0.004) in Group II. Similarly, the CFR at RIMA main stem were significantly higher at three months when compared to the values at one week after the surgical procedure: (RIMA)CFR (three months) = 2.47 +/- 0.7 versus (RIMA)CFR (one week) = 2.1 +/- 0.5 (p = 0.004) in Group I and (RIMA)CFR (three months) = 2.48 +/- 0.5 versus (RIMA)CFR (one week) = 2.08 +/- 0.4 (p = 0.008) in Group II.

CONCLUSION

The flow dynamic data, almost identical between patients undergoing off-pump and on-pump total arterial myocardial revascularization (TAMR) according to the RYG configuration, demonstrate that this technique can be applied with excellent results without the employment of cardiopulmonary bypass in selected coronary artery disease patients.

Off-pump multivessel coronary artery surgery in high-risk patients

BACKGROUND

Coronary artery bypass surgery on cardiopulmonary bypass is associated with significant morbidity and mortality, which may be more marked in high-risk patients. We evaluated our results of off-pump coronary artery bypass (OPCAB) in high-risk patients with multivessel coronary artery disease and compared them with results in similar patients who underwent operation on cardiopulmonary bypass.

METHODS

A total of 1,075 patients who underwent OPCAB between October 1996 and June 2001 and who had one or more of the following risk factors were included in the study: poor left ventricular function (EF < or = 30%), advanced age (> 70 years), left main stenosis, acute myocardial infarction, and redo coronary artery surgery. These patients were compared with 2,312 similar patients who underwent coronary artery bypass grafting on cardiopulmonary bypass during the same period. Preoperative risk factors, intraoperative variables, and postoperative results were analyzed and compared between two groups.

RESULTS

The average number of grafts was 3.0 +/- 0.4 and 3.2 +/- 0.3 in the off-pump (OPCAB) and on-pump (CCAB) groups, respectively. Hospital mortality was 3.2% and 4.5% in OPCAB and CCAB groups respectively (p = 0.109). Perioperative myocardial infarction, requirement of inotropic agents, stroke, and renal dysfunction were comparable in two groups. Intubation time (19 +/- 5 vs 24 +/- 6 hours, p < 0.001), mean blood loss (362 +/- 53 vs 580 +/- 66 mL, p < 0.001), atrial fibrillation (14.3 vs 19.7%, p < 0.001), and prolonged ventilation (4.6 vs 7.6%, p = 0.002) were less in OPCAB group. Intensive care unit stay (20 +/- 8 hours) and hospital stay (6 +/- 3 days) were significantly less in the OPCAB group (p < 0.001).

CONCLUSIONS

Off-pump coronary artery surgery can be safely performed in high-risk patients with multivessel coronary artery disease. Operative mortality is comparable to that associated with on-pump surgery, and avoidance of cardiopulmonary bypass is associated with reduced postoperative morbidity in these patients.

Off-pump coronary artery bypass grafting decreases morbidity and mortality in a selected group of high-risk patients

BACKGROUND

The ideal indication for off-pump coronary artery bypass grafting (OPCABG) has yet to be defined. High-risk surgical patients may benefit the most when cardiopulmonary bypass (CPB), aortic cross clamping, and cardioplegic arrest are avoided. The aim of this study was to determine whether off-pump coronary artery bypass grafting might decrease the operative morbidity and mortality in a select group of high-risk patients with multivessel coronary artery disease.

METHODS

Utilizing a Parsonnet risk stratification model we analyzed prospectively collected data on a cohort of high-risk coronary artery disease patients, which were operated on with beating-heart technology by the same group of surgeons in a tertiary care university medical center. High-risk patients were defined as those with a Parsonnet score of 15 or greater.

RESULTS

Fifty-seven multivessel disease OPCABG patients (over a period of 2 years) had markedly increased Parsonnet scores (24.3 +/- 10.6). The average ejection fraction of the patients was 42% (+/-12.3) and their age ranged from 52 to 85 years (mean 70.6 +/- 10.4, 26% women). Unstable angina was present in 42 patients (74%) and 10 patients underwent OPCABG within 24 hours of the occurrence of acute myocardial infarction. In addition to severe coronary artery disease 32% of the patients presented with congestive heart failure, insulin-dependent diabetes (18%), renal failure (22%), peripheral vascular disease (31%), pulmonary disease (18%), and neurologic disorders (14%). An average of 2.6 +/- 0.9 grafts/patient were performed and the posterior descending artery or marginal branches of the circumflex artery or both were grafted in 90%. The 30-day mortality rate was 3.5% (n = 2).

CONCLUSIONS

OPCABG can be performed with a reasonable low morbidity and mortality in this select group of high-risk patients. OPCABG is a reasonable, and might even be preferable, operative strategy in this high-risk group of patients.

Conversion to off-pump coronary bypass without increased morbidity or change in practice

BACKGROUND

This article examines the feasibility of complete conversion from conventional coronary artery operation to routine off-pump coronary bypass operation.

METHODS

Data on our first 285 off-pump procedures using the Octopus system (Medtronic Inc, Minneapolis, MN) represent our learning curve. This is a complete experience in coronary bypass surgery over 16 months.

RESULTS

The cohort was nonselected. All patients had at least two-vessel disease. Eight hundred seven grafts were performed (mean, 2.8 per patient) of which 647 grafts (84%) were arterial (mean, 2.3 per patient). One hundred seventy nine patients (63%) underwent total arterial revascularization. Eight patients required cardiopulmonary bypass; all other operations were completed off-pump. Complications were: mortality, 3 patients (1.5%); renal failure, 24 patients (8%); stroke, 2 patients (< 1%); and atrial fibrillation, 60 patients (21%). The morbidity data and frequency of arterial grafting did not differ from that of 355 patients who underwent coronary bypass operations in a preceding 18-month period.

CONCLUSIONS

Complete shift from routine use of cardiopulmonary bypass to nonselective off-pump coronary bypass operation is possible with a low conversion rate and without an apparent increase in morbidity or change in technique. Whereas short-term safety and efficacy seem certain, studies of long-term outcome are necessary before the eventual role of off-pump coronary bypass in myocardial revascularization can be defined.

[Beating heart in "aortic no-touch off-pump" techniques: a simple answer to complex surgical situations]

Three cases reports illustrate the concept of beating heart cardiac surgery and its advantages regarding the prevention of arterial emboli.

[Beating heart surgery and left ventricular dysfunction]

We report our experience with systematic coronary revascularization on the beating heart among patients with left ventricular dysfunction as defined by a left ventricular ejection fraction < or = 40%. Between September 1996 and April 2000, 500 off-pump (OPCAB) revascularizations were performed (95% of all revascularizations for the same time frame, single surgeon). Among them, 76 patients qualified as left ventricular dysfunction and were compared to a similar cohort of 237 patients operated on with cardiopulmonary bypass (CPB) during the same time frame. Age and sex distribution, average preoperative left ventricular ejection fraction and incidence of preoperative unstable angina were the same for both groups. On average, 3.04 +/- 0.89 and 2.97 +/- 0.69 grafts/patient were made in the OPCAB and CPB groups respectively (p = NS). Complete revascularization was achieved in 95% of the OPCAB group. Incidence of preoperative intra-aortic balloon assistance were higher in OPCAB (22% versus 9%, p = 0.005) whereas postoperative need for new intra-aortic balloon assistance was higher in CPB (8% versus 0%, p = 0.02). Incidence of postoperative myocardial infarction was comparable in both groups (6.5% versus 5.5%). Maximal creatinine phosphate of myocardial origin were lower in OPCAB group (beating heart: 32 +/- 52%, cardiopulmonary bypass: 45 +/- 51%, p = 0.055). Operative mortality was lower in OPCAB group although it did not reach statistical significance (beating heart: 2.6% versus cardiopulmonary bypass: 4.6%, p = 0.3). Complete coronary revascularization on the beating heart can be achieved in patients with left ventricular dysfunction with excellent outcome and low operative mortality.

Endothelin receptor subtype A blockade selectively reduces pulmonary pressure after cardiopulmonary bypass

BACKGROUND

The bioactive peptide endothelin-1 is elevated during and after cardiopulmonary bypass and exerts cardiovascular effects through its 2 receptor subtypes, endothelin-1A and endothelin-1B. Increased endothelin-1A receptor stimulation after cardiopulmonary bypass can cause increased pulmonary vascular resistance and modulate myocardial contractility. However, whether and to what degree selective endothelin-1A blockade influences these parameters in the postbypass setting is not completely understood.

OBJECTIVES

Our objective was to measure left ventricular function and hemodynamics in a porcine model of cardiopulmonary bypass after selective blockade of endothelin-1A.

METHODS

Adult pigs (n = 23) underwent 90 minutes of cardiopulmonary bypass and were randomized 30 minutes after bypass to receive a selective endothelin-1A antagonist (TBC 11251, 10 mg/kg; n = 13) or saline vehicle (n = 10).

RESULTS

After bypass and before randomization, pulmonary vascular resistance rose nearly 4-fold, and left ventricular preload recruitable stroke work fell to one third of baseline values (both P <.05). In the vehicle group pulmonary vascular resistance continued to rise, and preload recruitable stroke work remained reduced. However, after endothelin-1A blockade, the rise in pulmonary vascular resistance was significantly blunted compared with that in the vehicle group. Moreover, the reduction in pulmonary vascular resistance with endothelin-1A blockade was achieved without a significant change in systemic perfusion pressures.

CONCLUSIONS

The present study demonstrated that increased activity of the endothelin-1A receptor likely contributes to alterations in pulmonary vascular resistance in the postbypass setting. Selective endothelin-1A blockade may provide a means to selectively decrease pulmonary vascular resistance without significant effects on systemic hemodynamics.

Beating heart surgery or conventional CABG: are neurologic outcomes different?

Although there has been much debate about the causes of neurologic complications associated with coronary artery bypass grafting (CABG), there is good evidence linking such complications with some of the pathophysiologic changes associated with use of conventional cardiopulmonary bypass (CPB). Several studies indicate that it is possible to significantly lower risk of stroke and other central nervous system (CNS) morbidity in patients undergoing CPB for CABG by application of selected techniques and equipment modifications. The resurgence of interest in coronary revascularization by using beating heart surgery (BHS) offers a unique opportunity to evaluate neurologic outcome independent of CPB. Currently, BHS would appear to significantly reduce morbidity in the elderly and to decrease the costs and resource use in coronary revascularization patients. It is hoped that by understanding the mechanisms of CNS injury associated with CABG, techniques can be developed to decrease the risk of neurologic injury associated with coronary revascularization, whether or not CPB is used. Definitive conclusions regarding outcomes after best practice CPB or BHS await large-scale, risk-stratisfied multicenter trials.

Right heart assist ensures hemodynamic stability during beating heart coronary surgery on marginal arteries. An animal experimental porcine study

OBJECTIVES

In many heart centers myocardial revascularization using beating heart coronary surgery has partly replaced conventional coronary artery bypass grafting (cCABG) using cardiopulmonary bypass. However, access to the marginal arteries is problematic and hampered by space limitations, which might compromise the quality of the anastomoses and it entails a significant risk of hemodynamic instability subsequent to the manipulations of the heart. Hemodynamic impairment may be caused by dislocation of the low-pressure right atrium and ventricle. Therefore, it was hypothesized that the use of Right Heart Assist (RHA) may be able to ensure hemodynamic stability when tilting and manipulating the heart.

DESIGN

In an animal experimental model RHA was implemented in order to study the hemodynamic impact of dislocating the heart in a standardized fashion.

RESULTS

Dislocation of the unassisted heart to expose the first and second marginal branches caused a decline in arterial blood pressure, cardiac output and venous saturation of 38-48%. Supported by RHA this decrease was minimized to 0-17%.

CONCLUSION

RHA for beating heart procedures indicates several advantages: ample time and safety while making the anastomoses at the marginal branches, less space limitations and enhanced control of hemodynamic stability compared with no RHA. This operation technique is challenging current practice and indications, and may potentially replace cCABG for the majority of patients.

Increased incidence of acute ascending aortic dissection with off-pump aortocoronary bypass surgery?

BACKGROUND

An apparent increase in the incidence of acute ascending aortic dissection following off-pump coronary artery bypass grafting (OPCAB) led us to assess retrospectively the rate and circumstances of this complication in our institution on a consecutive series of patients undergoing aortocoronary bypass performed with and without extracorporeal circulation (ECC).

METHODS

A retrospective analysis of acute ascending aortic dissections complicating coronary artery bypass grafting surgery in 3,031 patients in our institution since April 1, 1995, was performed using the database of the Montreal Heart Institute.

RESULTS

There was a greater frequency of hypertension in the OPCAB group. Iatrogenic acute aortic dissection occurred in 3 patients among 308 operated on without ECC (0.97%) and 1 patient among 2,723 operated on under ECC (0.04%). This difference was statistically significant (p < 0.00001).

CONCLUSIONS

The risk of aortic dissection may be increased in OPCAB. Careful manipulation of the aorta with a single side-clamping and a control of the arterial pressure should be used to minimize aortic trauma. High-risk patients should undergo CABG without side-clamping of the aorta or CABG with ECC to prevent this redoubtable complication of myocardial revascularization.

Clinical outcomes and resource usage in 100 consecutive patients after off-pump coronary bypass procedures

BACKGROUND

Cardiopulmonary bypass initiates a cascade of inflammatory processes that may result in end-organ damage, leading to the increased prevalence of noncardiac complications. Therefore, off-pump coronary artery bypass graft (OP-CAB) procedures have recently been introduced into clinical practice.

METHODS

This study was a case-controlled study that compared the outcomes and cost of 100 consecutive OP-CAB procedures with a control group of 100 contemporary matched conventional coronary artery bypass grafting procedures. All operations were performed by a single surgeon (J.H.L. ) and complete revascularization that used off-pump techniques was achieved with the use of innovative exposure techniques to the lateral and posterior wall vessels.

RESULTS

An average of 3.1 grafts per patient were performed in the OP-CAB group (range, 1-5). The incidence of conversion to conventional coronary artery bypass grafting was 1%. The overall mortality rate was 2.0%. There were no instances of stroke, renal failure, or sternal infections in the OPCAB group. Thus, the OP-CAB group had a shorter length of stay (6.1+/-2.5 versus 7.1+/-3.3 d; P =.003), with a corresponding reduction in variable direct cost per case of 29% (P<.001).

CONCLUSION

Our experience suggests that OP-CAB procedures are feasible for most patients who currently require complete revascularization. It is associated with very a low morbidity rate and may represent the ideal revascularization strategy for patients at high risk for undergoing cardiopulmonary bypass.

Systematic off-pump coronary artery revascularization in multivessel disease: experience of three hundred cases

OBJECTIVE

We sought to report our recent experience with off-pump coronary artery revascularization in multivessel disease.

METHODS

Between October 1996 and December 1998, 300 off-pump beating heart operations were performed at the Montreal Heart Institute by a single surgeon, representing 94% of all procedures undertaken during this same time frame (97% for 1998). This cohort of patients was compared with 1870 patients operated on with cardiopulmonary bypass from 1995 to 1996.

RESULTS

Mean age, sex distribution, and preoperative risk factors were comparable for the two groups. On average, 2.92 +/- 0.8 and 2.84 +/- 0.6 grafts per patient were completed in the beating heart and cardiopulmonary bypass groups, respectively. A majority of patients (70%) had either a triple or quadruple bypass. Coronary anastomoses were achieved with myocardial mechanical stabilization and heart "verticalization." Ischemic time was shorter in the beating heart group (29.8 +/- 0.9 vs 45 +/- 0.4 minutes, P <.05). Similarly, the need for transfusion was significantly less in the beating heart group (beating heart operations, 34%; cardiopulmonary bypass, 66%; P <.005). Reduced use of postoperative intra-aortic counterpulsation, as well as a lower rise in creatine kinase MB isoenzyme, was observed in the beating heart group. Operative mortality rates (beating heart operations, 1. 3%; cardiopulmonary bypass, 2%) and perioperative myocardial infarction (beating heart operations, 3.6%; cardiopulmonary bypass, 4.2%) were comparable for the two groups.

CONCLUSION

In a majority of patients, off-pump complete coronary artery revascularization is an acceptable alternative to conventional operations, yielding good results given progressive experience, rigorous technique, and adequate coronary artery stabilization.