Total Arterial Off-Pump Coronary Artery Bypass Grafting for Revascularization of the Total Coronary System: Clinical Outcome and Angiographic Evaluation

Off-Pump Coronary Artery Bypass Grafting; is it Still Relevant?

Off-pump Coronary Artery Bypass Grafting (OPCAB) experienced a resurgence in the 1980s -2000s and developed steadily with improvement of the instrumentation and techniques. However questions about graft patency and long-term survival of OPCAB patients still exist. This review attempts to explore the current relevance of OPCAB.

Coronary Artery Bypass Surgery in End-Stage Renal Disease Patients

The number of patients requiring hemodialysis is continuously increasing around the world. Hemodialysis affects patient quality of life and it is also associated with a higher risk for cardiovascular events. In addition to traditional risk factors for cardiovascular events such as hypertension, hyperlipidemia, and diabetes, hemodialysis is associated with hyperphosphatemia, chronic inflammation, vascular calcification, and anemia which accelerate atherosclerosis, vascular stiffness, and cardiac ischemia. Treatment strategy for coronary revascularization in this progressive disease remains controversial. However, a systematic treatment including medical therapy and complete revascularization through a less invasive strategy should be considered in addressing this problem. This review discusses the epidemiology, vascular pathology and current treatment options in patients with end-stage renal disease requiring coronary revascularization.

Microcirculatory response during on-pump versus off-pump coronary artery bypass graft surgery

OBJECTIVES

The use of cardiopulmonary bypass (CPB) during coronary artery bypass graft surgery (CABG) is associated with a systemic inflammatory response, resulting in altered microcirculation. The aim of this study was to evaluate whether beating heart surgery can preserve the microcirculation.

METHODS

Sublingual microcirculation was characterized by a Sidestream Darkfield Imaging Microscope during off-pump (OPCABG) and on-pump (ONCABG) surgery. Microcirculatory parameters were evaluated during eight precise perioperative time points.

RESULTS

The quality of the microcirculation decreased during early ONCABG. OPCABG resulted in a significantly better microcirculation compared to ONCABG for three of six parameters during surgery. However, by the end of surgery and postoperatively, the microcirculatory parameters were no different between the groups.

CONCLUSIONS

While the results do not show a marked preservation of the microcirculation during and after OPCABG compared to ONCABG, they coincide with the body temperature fluctuations of each group during and after surgery. Our work suggests that active warming could impact the microcirculation parameters.

The relationship between total arterial revascularization and blood transfusion following coronary artery bypass grafting

BACKGROUND

Blood transfusion adversely affects the outcome of coronary artery bypass grafting (CABG), yet blood transfusion after CABG is still common. Total arterial revascularisation (TAR) is increasingly used in current practice but its impact on postoperative blood transfusion is not known.

METHODS

We reviewed the cardiothoracic and blood bank databases and collected data for isolated primary CABG patients from July 2007 to June 2012, excluding patients who had a single graft (n = 148). Perioperative variables of TAR patients (n = 745) were compared with patients who had one or more venous grafts (SVG, n = 1,761) for first-time isolated CABG. The conduits used in TAR patients were predominantly left internal thoracic and radial arteries. Matched group comparison of TAR and SVG patients was performed. The association of TAR with blood transfusion was investigated using multivariate and matched analysis.

RESULTS

Of 2,506 patients, the 745 (29.7 %) that had TAR were generally younger, with less complex coronary artery disease and less often diabetic. After correcting for these by 1:1 matching, the mean chest tube drainage and rates of blood transfusion remained significantly lower (p < .0001) in TAR patients. Indeed, red cells, platelets and fresh frozen plasma were significantly less frequently transfused in TAR patients. By multivariate analysis, TAR had an independent effect on reducing blood transfusion after CABG [odds ratio (OR) 0.67, 95 % confidence interval (CI) 0.47-0.97, p = .03].

CONCLUSIONS

TAR achieved predominantly with left internal thoracic and radial arteries substantially reduced blood transfusion rates after primary CABG. Further studies are warranted.

Computerized tomography may underestimate the patency of internal thoracic artery composite grafts

BACKGROUND

Multidetector-row computerized tomography (MDCT) has been regarded as useful for noninvasive assessment of the bypass grafts after coronary artery bypass grafting (CABG), but there have been few reports validating its accuracy in assessment of composite arterial graft patency.

METHODS

In 108 patients who underwent CABG with a Y-composite graft made of bilateral internal thoracic arteries (ITAs), early postoperative (mean interval, 4.9 months) MDCT findings were compared with the findings of subsequent conventional coronary angiography (19 patients, mean 4.7 months after initial MDCT) or later MDCT (89 patients, mean 31.0 months after surgery). A total of 248 grafts with 409 distal anastomoses (mean 3.8/patient) were assessed.

RESULTS

In the early MDCT, the left ITA was patent in 94.4%. The right ITA with multiple sequential anastomoses was completely patent in 73.8% and partially patent in 21.4%. Discrepancy of findings between early computed tomography (CT) and later imaging studies was found in 18 patients (16.7%). Fourteen (42.4%, 4 left and 10 right ITAs) among the 33 initially nonvisualized grafts showed improved patency in later MDCT or conventional angiogram. The positive predictive value of the early MDCT for ITA composite graft occlusion was calculated at 57.6% or lower, whereas the negative predictive value was 97.8% or higher.

CONCLUSIONS

For a composite graft made of bilateral ITAs, especially for those with multiple sequential anastomoses, MDCT may reflect only the functional patency and underestimate the actual anatomic patency.

Comparison of the radial artery and saphenous vein as composite grafts in off-pump coronary artery bypass grafting in elderly patients: a randomized controlled trial

Background and Objectives

Arterial grafts have a better long-term patency rate than saphenous vein (SV) when used in off-pump coronary artery bypass surgery (OPCAB). However, arterial grafts in elderly patients are often diseased. We sought to compare the early outcomes achieved by using the two different types of composite grafts.

Subjects and Methods

We conducted a randomized trial to compare radial artery (RA) and SV composite grafts based on the in situ left internal mammary artery in 60 elderly (>70 years old) patients, who were scheduled to undergo OPCAB. Clinical outcomes and 1-year postoperative CT angiography results were compared. The quality of the conduit was evaluated by employing vascular ultrasonography, optical coherence tomography (OCT), and histologic examination.

Results

No differences in immediate postoperative morbidity and mortality were observed between the two groups. Early postoperative CT angiography revealed a SV patency rate of 100%, which was not different from that of RA composite grafts (99.1%). CT angiography after a year showed an overall patency rate of 96.3%. The overall patency rate of the SV group at 1 year was 94.7%, which was similar to that of the RA group (97.4%). Also, there was no difference in overall survival rate between the two groups. Vascular ultrasonographic images showed strong correlations between OCT and histopathology.

Conclusion

Our analysis of early outcomes revealed that the SV could be used as an alternative composite graft to the RA in elderly patients. Vascular ultrasonography is an accurate, real-time, and reproducible method for assessing the quality of the RA conduit.

Aortic no-touch technique makes the difference in off-pump coronary artery bypass grafting

OBJECTIVES

Both off-pump surgery (OPCAB) and aortic no-touch technique reduce stroke after coronary artery bypass grafting (CABG). We evaluate the impact of partial aortic clamping (PC) versus a no-touch technique using either the HEARTSTRING system (HS) or total arterial revascularization (TAR) on the incidence of stroke.

METHODS

From 1999 [corrected] to 2009, 4314 patients underwent myocardial revascularization. Patients either underwent OPCAB (n = 2203) or conventional on-pump CABG (n = 2111). The OPCAB cohort was divided into 2 subgroups: patients requiring proximal anastomosis applying PC (n = 567) or a "no-touch" technique with the HS (n = 1365). Patients who received TAR (n = 271) served as a control group (gold-standard). Data collection was performed prospectively using a propensity score (PS)-adjusted regression analysis. End points were stroke, mortality, major adverse cardiac and cerebrovascular events (MACCE), and a noncardiac composite end point including respiratory failure, renal failure, and bleeding.

RESULTS

The mortality rate (1.6% vs 2.4%; propensity-adjusted odds ratio [PAOR] = 0.51; CI 95%, 0.26-0.99; P = .047), MACCE (7.9% vs 17.1%; PAOR = 0.67; CI 95%, 0.52-0.84; P = .001) including myocardial infarction (1.1% vs 2.2%; PAOR = 0.50; CI 95%, 0.26-0.98; P = .044) and stroke (1.1% vs 2.4%; PAOR = 0.35; CI 95%, 0.17-0.72; P = .005) as well as the noncardiac composite (PAOR = 0.46; CI 95%, 0.35-0.91; P < .001) were significantly lower for OPCAB when compared with on-pump CABG. In comparison with PC, OPCAB patients undergoing the HS approach had significantly lower frequencies of stroke (0.7% vs 2.3%; PAOR = 0.39; CI 95%, 0.16-0.90; P = .04) and MACCE (6.7% vs 10.8%; PAOR = 0.55; CI 95%, 0.38-0.79; P = .001), and these results were similar to those of the control group, who underwent no-touch TAR (stroke rate, 0.8%; MACCE, 7.9%).

CONCLUSIONS

Our results confirm that OPCAB is superior with regard to risk-adjusted outcomes. There is no difference in the stroke rate when comparing on-pump CABG versus applying partial aortic crossclamping in OPCAB. Whenever a proximal anastomosis is needed, a no-touch technique should be applied, that is, using the HS device.

Outcome of composite arterial Y-grafts in off-pump coronary artery bypass

The efficacy of using composite arterial Y-grafts in off-pump coronary artery bypass has not been established. We assessed graft patency, long-term clinical outcomes, and the indications for composite arterial Y-grafting by reviewing 53 patients who underwent primary isolated elective off-pump coronary artery bypass with composite arterial Y-grafts between January 2002 and December 2008. Coronary angiography or 64-slice multidetector computed tomographic coronary angiography was used to assess graft patency. Follow-up raged from 18 to 97 months. The rates of mortality, graft failure, and recurrence of ischemic heart disease were 0%, 22.6%, and 13.2%, respectively. Only 4 (7.5%) patients required additional procedures (percutaneous coronary interventions or repeat surgery) because of graft failure. A significantly higher rate of graft failure was evident when one end of the composite graft was anastomosed to a 75% stenosed branch of a native coronary artery and the other end to a branch with >90% stenosis. The long-term patency of composite arterial Y-grafts in off-pump coronary artery bypass requires proper judgment of the indications.

Management of patients with a calcified aorta or low ejection fraction undergoing multivessel coronary revascularization

Off-pump coronary artery bypass surgery (OPCAB) provides an alternative method of surgical revascularization by allowing coronary anastomoses to be constructed without the use of cardiopulmonary bypass and without manipulation of the aorta. The presence of a calcified aorta is one of the strongest indications for OPCAB because both distal and proximal anastomoses can be performed without cannulation or clamping of the aorta. In patients with left ventricular dysfunction, OPCAB techniques allow for revascularization without the need for global myocardial ischemia associated with cardioplegic arrest.

Four-year outcome of OPCAB no-touch with total arterial Y-graft: making the best treatment a daily practice

BACKGROUND

A retrospective, single-center 4-year clinical study of the off-pump coronary artery bypass grafting no-touch technique with arterial conduits (Y-graft) was compared with the Syntax trial.

METHODS

Four hundred consecutive patients ("all-comers") who underwent coronary surgery between 2004 and 2008 at the Thorax Center Twente (TCT) formed the study group. The primary end point was in-hospital and 12-month major cardiovascular or cerebrovascular event (MACCE). Event rates of MACCE were based on life tables, and overall MACCE was determined by Kaplan-Meier analysis.

RESULTS

In-hospital mortality was 0.2%. Cumulative 1-year survival was 98.2%, and freedom from MACCE was 94.7% +/- 1.1%. Cumulative 4-year survival and freedom from MACCE were 91.2% +/- 2.4% and 82.1% +/- 3.0%, respectively. There were no significant differences in the baseline characteristics between the patients of the TCT group and the surgical arm of the Syntax trial. Repeat revascularization, MACCE, and symptomatic graft occlusion in the TCT group were significantly lower than in the Syntax trial. The event rate of myocardial infarction and all-cause death in the TCT group were significantly lower than those of the percutaneous coronary intervention arm of the Syntax trial. There was a clear trend toward a reduction of the event rate of stroke in the TCT group (0.8%) compared with the surgical arm of the Syntax trial (2.2%). There was no significant difference of stroke rate between the TCT group and the percutaneous coronary intervention arm of the Syntax trial.

CONCLUSIONS

A state-of-the-art surgical technique such as off-pump coronary artery bypass grafting no-touch can further improve the advantage of surgical treatment with respect to percutaneous coronary intervention. Off-pump coronary artery bypass grafting no-touch surgery can be the treatment of choice for patients with three-vessel disease and left main stenosis.

Is diabetic nephropathy a predicted risk factor?--Kaplan-Meier and multivariate analysis of confounding risk factors in off-pump coronary artery bypass grafting for chronic dialysis patients

BACKGROUND

The purpose of this study was to investigate the preoperative risk factors of performing off-pump coronary artery bypass grafting (OPCAB) in patients on chronic dialysis.

METHODS AND RESULTS

The 41 consecutive patients on chronic dialysis who underwent OPCAB from February 2000 to April 2006 at the National Cardiovascular Center were studied retrospectively. Of them, 29 had diabetic nephropathy (DN group) and the remaining 12 did not (NDN group). There were significant differences in the duration of dialysis before surgery (9.1 +/-7.5 years in NDN vs 4.2 +/-5.5 years in DN, P=0.028) and low cardiac function (left ventricular ejection fraction <30%), which was recognized only in the DN group (7/29, P=0.048). The early mortality rate was 6.9% (2/29) in the DN group and 16.7% (2/12) in the NDN group (P=0.349). The actuarial survival rates in the DN group were 85% at 1 year, 45% at 3 years, and 30% at 5 years, whereas in the NDN group they were 71%, 49%, and 49%, respectively (P=0.789). arteriosclerosis obliterans (ASO) and age (>65 YEARS) were independent risk factors of late death.

CONCLUSIONS

For patients on chronic dialysis ASO and aging were predicted risk factors for OPCAB, whereas diabetic nephropathy was not.

Configurations and classifications of composite arterial grafts in coronary bypass surgery

The aim of this review is to present the configurations and classifications of composite arterial grafts in coronary bypass surgery. Articles were collected by tracking references cited in the literature with regard to the configurations of composite arterial grafts in coronary bypass surgery. Figures of the configurations were drawn in accordance to the schematic drawings, angiograms, photographs, table contents or written captions of the literature. According to their structural nature, composite arterial grafts can be classified as: (i) alphabetical (Y, T, I, U, K, X and H) and (ii) complex grafts (TY, loop, pi and sling grafts). According to the conduits that form the composite graft, they can be classified as: (i) definite (all standard alphabetical grafts, classic pi and sling grafts); (ii) varying [internal mammary artery (IMA) loop, modified pi graft]; and (iii) indefinite conduit graft (TY graft). According to their application in coronary artery bypass grafting (CABG), they can be divided into complete arterial revascularization for: (i) triple vessel disease (T, Y, K, X, TY, pi and sling grafts); (ii) two vessel disease (U, right Y, and two-thirds right IMA T grafts); and (iii) single vessel disease, mainly the left anterior descending artery with or without the diagonal branch (H, I, IMA loop and left IMA T grafts). According to the CABG method, they can be classified as: (i) for conventional CABG (sling graft); (ii) for minimally invasive direct coronary artery bypass (H graft); and (iii) for both conventional CABG and off-pump coronary artery bypass (T, Y, U, K, I, TY, IMA loop, and pi grafts). Standard Y and T grafts have been accepted as the common figurations of composite arterial grafts to maximum graft length for the bypass of triple vessel disease. Composite arterial grafts overcome the limited availability of arterial conduits for performing total arterial myocardial revascularization, allow a gain in conduit length, and minimize the ascending aorta manipulation.

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.

Arterial grafting for myocardial revascularization: how better is it?

PURPOSE OF REVIEW

Arterial conduits are becoming popular in cardiac surgery. Clinical studies and long-term follow-ups have proven that this technique provides satisfactory long-lasting results. The purpose of this review is to give an overview of the main articles from recent literature and compare the latest results.

RECENT FINDINGS

Arterial conduits are currently used in cardiac surgery and clinical follow-ups are confirming some advantages in performing multiple arterial revascularization compared to the saphenous vein and the mammary artery. Mid-term follow-ups are encouraging the use of the radial artery as the second conduit of choice after the internal mammary artery. Moreover, off-pump cardiac surgery is an alternative to perform extensive myocardial revascularization in selected patients. Use of in-situ mammary arteries and off-pump surgery has already been described as the ideal solution to guarantee the 'no touch aorta technique'. Recent results lead us to use the radial artery and the gastroepiploic artery as complement composite grafts to perform total arterial myocardial revascularization during off-pump coronary surgery.

SUMMARY

Arterial grafting provides satisfactory results. The second graft of choice after the mammary artery is the radial artery, but long-term results are still not available. To reduce the risk of major neurological complications, selected patients benefit from off-pump arterial revascularization.

Redo off-pump coronary bypass grafting with arterial grafts for Kawasaki disease

Surgical revascularization for coronary artery lesions secondary to Kawasaki disease is relatively uncommon. The late stenosis of the saphenous vein graft is the problem to be solved. We report a case of redo off-pump coronary bypass grafting in a 35-year-old man, 20 years after bypass grafting using a saphenous vein graft. Off-pump total arterial revascularization was performed uneventfully. The procedure comprised grafting of bilateral internal thoracic arteries to left anterior descending branch and obtuse marginal branch, and radial artery to AV branch and posterior descending branch. Off-pump total arterial revascularization is a safe and less invasive procedure at the time of redo operation, even for patients with Kawasaki disease.

Off-Pump Coronary Artery Bypass Grafting for Acute Myocardial Infarction

BACKGROUND

The aim of this study was to evaluate the surgical results of off-pump coronary artery bypass grafting (OPCAB) for patients with acute myocardial infarction (AMI) within 14 days of the infarction.

METHODS AND RESULTS

From April 2000 to January 2005 among 841 patients who underwent OPCAB, 43 consecutive patients (5.1%) were examined. Mean age at operation was 69.5 years and mean time from the onset of AMI to surgery was 4.6 days. Seventeen patients (39.5%) had left main trunk disease. Three patients (7.0%) underwent OPCAB following unsuccessful percutaneous coronary intervention, and 1 patient (2.3%) underwent redo procedure 9 years after previous coronary artery bypass grafting (CABG). Six patients (14%) were admitted in cardiogenic shock. Intraaortic balloon pumping was inserted preoperatively in 20 patients (46.5%). The average maximum creatine kinase-myocardial band was 139+/-181 (U/L). The mean number of grafts was 3.2 and the rate of complete revascularization was 91%. Two of six patients with preoperative cardiogenic shock were converted to on-pump beating CABG due to ventricular arrythmia. The early graft patency rate was 98%. All patients survived except 2 with preoperative cardiogenic shock.

CONCLUSIONS

OPCAB can be performed after AMI as a relatively low-risk procedure with an acceptable mortality rate, even within 14 days of the infarction.

Meta-analysis of randomized trials comparing off-pump with on-pump coronary artery bypass graft patency

BACKGROUND

Off-pump coronary artery bypass graft surgery (OPCAB) is increasingly becoming a widely used technique and challenges conventional on-pump coronary artery bypass grafting as the standard surgical therapy for coronary artery disease. Little information, however, is available concerning postoperative performance of bypass grafts done with this new technique. The aim of this study is to assess differences in graft patency between OPCAB and coronary artery bypass grafting by meta-analysis of data published in randomized trials.

METHODS

A literature search for the period beginning January 1990 until December 2004 supplemented with manual bibliographic review was performed for all peer-reviewed English-language publications. A systematic overview (meta-analysis) of randomized trials was conducted to assess differences between OPCAB and coronary artery bypass grafting in graft occlusion rates.

RESULTS

Literature search yielded five comparable randomized studies, for a total of 872 and 998 grafts performed during OPCAB and coronary artery bypass grafting procedures, respectively. Meta-analysis of these studies showed an increased risk of graft occlusion in the OPCAB group of patients, both when all the studies were analyzed together (odds ratio, 1.51; 95% confidence intervals, 1.15 to 1.99; p = 0.003), and when low-quality (odds ratio, 1.46; 95% confidence intervals, 1.05 to 2.03; p = 0.02) and high-quality (odds ratio, 1.65; 95% confidence intervals, 0.99 to 2.75; p = 0.05) studies were analyzed separately.

CONCLUSIONS

Cumulative analysis of the few prospective randomized studies currently available in the literature documents a reduction in postoperative patency of coronary artery bypass grafts performed during OPCAB procedures. The risk of reduced graft patency needs to be considered when choosing OPCAB as tailored strategy for selected patients.