Angiographic Equivalency of Off-Pump Saphenous Vein and Arterial Composite Grafts at One Year

Five-year patency for the no-touch saphenous vein and the left internal thoracic artery in on- and off-pump coronary artery bypass grafting

BACKGROUND

Randomized trials show high long-term patency for no-touch saphenous vein grafts in coronary artery bypass grafting. The patency rate in off-pump coronary bypass surgery for these grafts has not been investigated. Our center participated in the CORONARY randomized trial, NCT00463294. This is a study aimed to assess the patency of no-touch saphenous veins in on- versus off-pump coronary bypass surgery at five-year follow-up.

METHODS

Fifty-six patients were included. Forty of 49 patients, alive at 5 years, participated in this follow-up. There were 21 and 19 patients in the on- and off-pump groups respectively. No-touch saphenous veins were used to bypass all targets and in some cases the left anterior descending artery. Graft patency according to distal anastomosis was evaluated with computed tomography angiography.

RESULTS

The five-year patency rate was 123/139 (88.5%). The patency for the no-touch vein grafts was 57/64 (89.1%) in the on-pump versus 37/45 (82.2%) in the off-pump group. All left internal thoracic arteries except for one, 29/30 (96.6%), were patent. All vein grafts used to bypass the left anterior descending and the diagonal arteries were patent 32/32. The lowest patency rate for the saphenous veins was to the right coronary territory, particularly in off-pump surgery (80.0% vs. 62.5% for the on- respective off-pump groups).

CONCLUSIONS

Comparable 5-year patency for the no-touch saphenous veins and the left internal thoracic arteries to the left anterior descending territory in both on- and off-pump coronary artery bypass grafting. Graft patency in off-pump CABG is lower to the right coronary artery.

A comparison of immediate postoperative complications in using left internal mammary artery + vein versus only vein as conduit in patients undergoing off-pump coronary artery bypass grafting

Objective:

The objective of the study is to compare the immediate postoperative cardiac complications in patients undergoing off-pump coronary artery bypass grafting (OPCABG) using mixed (arterial and venous grafts) versus only venous grafts and to compare the requirement of packed red cell units and intra-aortic balloon pump (IABP) in both the groups.

Materials and Methods:

This was an observational, analytical, prospective study.

Sample Size:

Fifty new patients were included in the study.

Inclusion/Exclusion Criteria:

Patients diagnosed with triple-vessel coronary artery disease (CAD) undergoing OPCABG with an ejection fraction (EF) of more than 30%. Patients who have undergone prior CABG, EF <30%, preexisting valvular heart disease, any evidence pulmonary hypertension, preoperative IABP, any history of neurological dysfunction, left atrium size more than 5.5 cm, and history of coagulation disorder was excluded from the study.

Results:

The most common immediate postoperative cardiac complication observed was atrial fibrillation followed by ventricular arrhythmias in both the groups. There was no statistically significant difference in complication rate between the two groups. Postoperative requirement of IABP and requirements of blood products were also similar in both the groups.

Conclusion:

Patients undergoing off-pump CABG have similar immediate postoperative complications irrespective of the type of conduit used.

Comparison of the Plasma Metabolome Profiles Between the Internal Thoracic Artery and Ascending Aorta in Patients Undergoing Coronary Artery Bypass Graft Surgery Using Gas Chromatography Time-of-Flight Mass Spectrometry

BACKGROUND

The left internal thoracic artery (LITA) has been used as the first conduit of choice in coronary artery bypass grafting (CABG) because of excellent long-term patency and outcomes. However, no studies have examined substances other than nitric oxide that could be beneficial for the bypass conduit, native coronary artery or ischemic myocardium. This study was conducted to evaluate differences in metabolic profiles between the LITA and ascending aorta using gas chromatography-time of flight-mass spectrometry (GC-TOF-MS).

METHODS

Twenty patients who underwent CABG using the LITA were prospectively enrolled. Plasma samples were collected simultaneously from the LITA and ascending aorta. GC-TOF-MS based untargeted metabolomic analyses were performed and a 2-step volcano plot analysis was used to identify distinguishable markers from two plasma metabolome profiles. Semi-quantitative and quantitative analyses were performed using GC-TOF-MS and enzyme-linked immunosorbent assay, respectively, after selecting target metabolites based on the metabolite set enrichment analysis.

RESULTS

Initial volcano plot analysis demonstrated 5 possible markers among 851 peaks detected. The final analysis demonstrated that the L-cysteine peak was significantly higher in the LITA than in the ascending aorta (fold change = 1.86). The concentrations of intermediate metabolites such as L-cysteine, L-methionine and L-cystine in the 'cysteine and methionine metabolism pathway' were significantly higher in the LITA than in the ascending aorta (2.0-, 1.4- and 1.2-fold, respectively). Quantitative analysis showed that the concentration of hydrogen sulfide (H₂S) was significantly higher in the LITA.

CONCLUSION

The plasma metabolome profiles of the LITA and ascending aorta were different, particularly higher plasma concentrations of L-cysteine and H₂S in the LITA.

Saphenous vein: advances

Although the saphenous vein (SV) is a widely used conduit for coronary artery bypass graft surgery (CABG), lower long-term graft patency rates and worse clinical outcomes have been reported after CABG performed with SV grafts compared with CABG performed with internal thoracic artery (ITA) grafts. Of various efforts to overcome the limitations of SV that are resulting from structural and functional differences from arterial conduit, recent improvement in harvesting techniques including no-touch technique, surgical strategy of using the SV as part of a composite graft over an aortocoronary bypass graft, and external stenting of the SV will be discussed in this topic.

Comparison of graft patency following coronary artery bypass grafting in the left versus the right coronary artery systems: a systematic review and meta-analysis

Although coronary artery bypass grafting has been the standard of care for patients with complex coronary artery disease for over 50 years, the evolution of graft patency over time in the left versus the right coronary systems remains poorly documented. This systematic review and meta-analysis aimed to characterize the evolution of graft patency over time comparing the left (excluding left anterior descending artery) and right coronary systems, with an emphasis on the comparison of venous versus arterial grafts and symptomatic versus asymptomatic patients. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) and MEDLINE from inception to August 2016. We also searched clinical trials registers and reference lists of relevant studies. We included randomized clinical trials and observational studies comparing graft patency in the left versus the right coronary systems. Our outcome was graft patency defined as a binary variable according to whether grafts were reported as patent or failed at the time of angiogram. Data collection and analysis were performed according to the methodological recommendations of the Cochrane Collaboration. From a total 2275 papers, 52 studies were included in the qualitative analysis and 48 studies (including 36 006 grafts) in the meta-analysis. There was a 3.3% significant difference between the left-sided and right-sided graft patency, and the difference appeared to increase over time. Furthermore, patency of arterial grafts was higher in the left coronary system, while venous grafts performed similarly irrespective of the coronary circulation. Symptom recurrence also seemed related to a higher failure rate in the right coronary circulation. However, the high degree of heterogeneity precluded drawing definite conclusions. This meta-analysis suggested that graft patency might be better for left-sided vessels and that this difference might be driven by the better performance of arterial grafts in the left coronary system. However, evidence currently available is limited, and further research is warranted to understand whether certain grafts achieve better patency in the right versus the left coronary circulations.

Saphenous vein versus right internal thoracic artery as a Y-composite graft: Five-year angiographic and clinical results of a randomized trial

OBJECTIVES

We compared the 5-year graft occlusion rates and midterm clinical outcomes of saphenous vein composite grafts with those of right internal thoracic artery composite grafts in patients who were enrolled in the SAphenous VEin versus Right Internal Thoracic Artery as a Y-Composite Graft trial.

METHODS

Of 224 eligible patients with multivessel coronary artery disease who were randomized to undergo off-pump revascularization using the saphenous vein (saphenous vein group, n = 112) or right internal thoracic artery (right internal thoracic artery group, n = 112) as Y-composite grafts based on the in situ left internal thoracic artery from September 2008 to October 2011, 219 patients (saphenous vein group, n = 109; right internal thoracic artery group, n = 110) entered the analysis. A third limb conduit to lengthen the graft limb for complete revascularization was used in 47 patients (saphenous vein group vs right internal thoracic artery group, 8 vs 39). Postoperative 5-year (61.7 ± 5.2 months) angiograms were performed in 186 patients (84.9%; saphenous vein group = 95; right internal thoracic artery group = 91). Follow-up was complete in 97.7% (214/219) of patients with a median follow-up of 80.7 months.

RESULTS

The overall graft occlusion rate was 3.6% at 5 years (3.5% in the saphenous vein group vs 3.7% in the right internal thoracic artery group, P = .910). The 5-year occlusion rate of the second limb conduits in the saphenous vein group was 4.3% and was noninferior to that of the right internal thoracic artery group (2.4%) within the 95% 2-sided confidence interval of -1.4% to 5.2% (P < .001 for noninferiority). No statistically significant differences were found in the overall survival (P = .439) and the freedom from major adverse cardiac and cerebrovascular event rates (P = .354) at 5 and 8 years between the 2 groups.

CONCLUSIONS

The saphenous vein composite grafts were noninferior to the right internal thoracic artery composite grafts in terms of 5-year graft occlusion rates and midterm clinical outcomes.

Evaluation of coronary artery-saphenous vein composite grafts: the aortic no-touch technique

We retrospectively compared the results of conventional coronary artery bypass grafting (CABG) performed on patients who showed no preoperative evidence of serious atherosclerosis of the ascending aorta with the results of the aortic no-touch technique (using coronary artery-saphenous vein composite grafts) on CABG patients who did show such evidence. From 2003 through 2012, 3,152 consecutive patients underwent isolated primary CABG at our hospital. We chose 360 for the current study. The study group (n=120) comprised patients who had undergone operation via the aortic no-touch technique. Propensity-score-matching (1:2) was used to select the control group of 240 patients who had undergone conventional CABG. Early and late survival rates, reintervention-free survival rates, and freedom from cardiac death were compared. Early and late mortality rates were similar in the study and control groups (P=0.19 vs P=0.29, respectively), as were cardiac-related death (2.5% vs 2.1%, respectively; P=0.53) and overall death (8.3% vs 7.9%, respectively; P=0.51). Overall survival rates were 91.7% vs 92.1% and freedom-from-cardiac-death rates were 97.4% vs 97.5% (P=0.71 vs P=0.78, respectively; mean follow-up period, 5.27 ± 2.51 yr). Reintervention-free survival rates were also similar (96.7% vs 98.8%, respectively; P=0.2). As a result of the similar rates of early and late survival, reintervention-free survival, and freedom from cardiac death, we conclude that the aortic no-touch technique with composite grafts might be a reasonable option in patients who have atherosclerotic ascending aorta that cannot be clamped.

Composite versus conventional coronary artery bypass grafting strategy for the anterolateral territory: study protocol for a randomized controlled trial

Background

In severe coronary artery disease, coronary artery bypass grafting (CABG) surgery is indicated to re-establish an adequate blood supply to the ischemic myocardium. Effectiveness of CABG surgery for symptom relief and mortality decrease should therefore depend on bypass graft patency. As bypass using a left internal mammary artery (LIMA)-to-left anterior descending coronary artery (LAD) anastomosis allows the best results in terms of graft patency, we designed a new surgical technique using a saphenous vein graft as a venous bridge to distribute the LIMA flow to the cardiac anterolateral territory. This novel strategy could extend the patency benefits associated to the LIMA. Other potential benefits of this technique include easier surgical technique, possibility to use saphenous vein grafts as vein patch angioplasty, shorter saphenous vein grafts requirement and reduced or eliminated manipulations of the ascendant aorta (and associated stroke risk).

Methods/Design

Between July 2012 and 2016, 200 patients undergoing a primary isolated CABG surgery using cardiopulmonary bypass with a LAD bypass graft and at least another target on the anterolateral territory will be randomized (1:1) according to 1) the new composite strategy and 2) the conventional strategy with a LIMA-to-LAD anastomosis and revascularization of the other anterolateral target(s) with a separated aorto-coronary saphenous vein graft. The primary objective of the trial is to assess whether the composite strategy allows non-inferior anterolateral graft patency index (proportion of non-occluded CABGs out of the total number of CABGs) compared to the conventional technique. The primary outcome is the anterolateral graft patency index, evaluated at one year by 256-slice computed tomography angiography. Ten years of clinical follow-up is planned to assess clinical outcomes including death, myocardial infarction and need for revascularization.

Discussion

This non-inferiority trial has the potential to advance the adult cardiac surgery field, given the potential benefits associated with the composite grafting strategy.

Trial registration

ClinicalTrials.gov: NCT01585285.

A novel composite coronary bypass graft strategy: the saphenous vein bridge--a pilot study

OBJECTIVES

The aim of this pilot study was to describe and assess the safety of a novel composite graft technique for coronary artery bypass grafting (CABG) surgery. A saphenous vein is grafted to the left anterior descending artery (LAD) and other anterolateral coronary arteries, creating a saphenous vein bridge (SVB) and the left internal mammary artery (LIMA) is anastomosed to the SVB, distributing the blood flow distally (LIMA-SVB).

METHODS

All patients who underwent CABG with the LIMA-SVB between 2005 and 2008 at our centre were enrolled in this study. Perioperative data were retrospectively collected from hospital charts, and the clinical follow-up was completed by telephone interview. Graft patency was assessed by computed tomography angiography (CTA) in patients with the longest follow-up time (n = 20).

RESULTS

A total of 256 patients (mean age: 67 ± 12 years; 79% male) received 4.0 ± 1.0 grafts, including 2.2 ± 0.4 distal grafts provided by the LIMA-SVB. Nine (3.5%) deaths and 4 (1.6%) myocardial infarctions (MIs) were noted in the perioperative period. With a median follow-up time of 36 months [inter-quartile range 31-44], 1 (0.5%) MI and 2 (1.0%) strokes were reported. At 51 months post-surgery [47-53], CTA demonstrated a LIMA pedicle (n = 20) and SVB (n = 42) patency rate of 100 and 93%, respectively. Specifically, the LIMA-SVB patency rate was 100% to the LAD and 85% to diagonal arteries. Aortocoronary vein grafts (n = 38) patency rate in the same patients was 87%.

CONCLUSIONS

Revascularization of the anterolateral territory using the LIMA-SVB is a promising approach considering its clinical safety and favourable patency rate results. A prospective randomized clinical trial is underway to compare this technique to conventional CABG.