Time-Varying Survival Benefit of Radial Artery Versus Vein Grafting: A Multiinstitutional Analysis

Twenty-year outcomes of free and I-composite radial artery grafts for coronary artery revascularization

PURPOSE

To compare the 20-year outcomes of coronary artery grafting (CABG) using radial artery (RA) grafts (free and I-composite) and internal thoracic artery (ITA) grafts.

METHODS

Long-term graft patency was evaluated in patients who underwent isolated CABG between August, 1996 and January, 2022. The long-term graft patency of free RA grafts, I-composite ITA-RA grafts, and saphenous vein (SV) grafts were compared.

RESULTS

The RA was used as a coronary bypass conduit in 111 of the 246 patients enrolled in this study. The RA patency after 10 and 20 years was 94.2% and 76.6%, respectively. Landmark analysis showed that although graft patency for up to 10 years did not differ between the RA and ITA grafts (hazard ratio = 0.87; P = 0.8), patency of the ITA grafts was better from 10 to 20 years post-surgery (hazard ratio = 0.19; P = 0.013). The 20-year graft patency of the I-composite RA grafts was better than that of the free RA grafts (80.0% vs. 72.4%; P = 0.029), but not significantly different from that of the ITA grafts (80.0% vs. 90.7%; P = 0.24).

CONCLUSIONS

The 20-year patency of the I-composite ITA-RA graft was better than that of the free RA graft; therefore, the I-composite graft may be an effective conduit for CABG.

Differences in long-term survival outcomes after coronary artery bypass grafting using single vs multiple arterial grafts: a meta-analysis with reconstructed time-to-event data and subgroup analyses

OBJECTIVE

We reviewed the available literature on patients with coronary artery disease undergoing isolated coronary artery bypass grafting (CABG) with either single (SAG) or multiple arterial grafting (MAG).

METHODS

Original research studies that evaluated the long-term survival of MAG versus SAG were identified, from 1995 to 2022. The median overall survival (OS) and event-free OS were the primary endpoints. Comparison of median OS between the right internal mammary artery (RIMA) and radial artery (RA) as a second arterial conduit was the secondary endpoint. Subgroup analyses were performed regarding patients older than 70 years, with diabetes mellitus, and females. A sensitivity analysis was performed with the leave-one-out method.

RESULTS

Forty-four studies were included in the qualitative and thirty-nine in the quantitative synthesis. After pooling data from 180 to 459 patients, the MAG group demonstrated a higher OS (HR, 0.589; 95% CI, 0.58-0.60; p < 0.0001) and event-free OS compared with the SAG group (HR, 0.828; 95% CI, 0.80-0.86; p < 0.0001). In addition, RITA was associated with superior OS compared with RA as a second arterial conduit (HR, 0.936; 95% CI, 0.89-0.98; p = 0.009). MAG was also superior to SAG in patients over 70 years, females, and patients with diabetes mellitus. Sensitivity analysis demonstrated a small-size study effect on the female subgroup analysis.

CONCLUSION

The present meta-analysis indicates that MAG is associated with enhanced survival outcomes compared to SAG for patients undergoing isolated CABG.

Comparison of free arterial and saphenous vein grafting in outcomes after coronary bypass surgery

Objectives. The goal of this study was to examine whether the use of free arterial grafts could reduce the need for repeated revascularization and all-cause mortality in patients undergoing coronary artery grafting. Design. The cohort study included 17,354 consecutive adults with isolated coronary artery grafting from 2000 to 2016 in three cardiac surgery centers. Data were obtained from the Western Denmark Heart Registry. Propensity matching with 24 factors was used to establish comparable groups of patients receiving either vein grafts (n = 1019) or free arterial grafts (n = 1019) for outcome analysis. Results. The need for repeated revascularization and all-cause mortality was similar in both graft groups at 10 years of follow-up. Creatine-Kinase MB Isoenzyme >100 μg/L increased the risk of repeated revascularization rate after 1, 5 and 10 years. Conclusions. Long-term outcomes in revascularization and survival are comparable after free arterial or saphenous vein grafting.

Long-term Outcomes of Multiple Arterial Coronary Artery Bypass Grafting: A Population-Based Study of Patients in British Columbia, Canada

Importance

Although the long-term survival advantage of multiple arterial grafting (MAG) vs the standard use of left internal thoracic artery (LITA) supplemented by saphenous vein grafts (LITA+SVG) has been demonstrated in several observational studies, to our knowledge its safety and other long-term clinical benefits in a large, population-based cohort are unknown.

Objective

To compare the safety and long-term outcomes of MAG vs LITA+SVG among overall and selected subgroups of patients.

Design, Setting, and Participants

In this population-based observational study, we included 20 076 adult patients with triple-vessel or left-main disease who underwent primary isolated coronary artery bypass grafting (MAG, n = 5580; LITA+SVG, n = 14 496) in the province of British Columbia, Canada, from January 2000 to December 2014, with follow-up to December 2015. We performed propensity-score analyses by weighting and matching and multivariable Cox regression to minimize treatment selection bias.

Exposures

Multiple arterial grafting or LITA+SVG.

Main Outcomes and Measures

Mortality, repeated revascularization, myocardial infarction, heart failure, and stroke.

Results

Of 5580 participants who underwent MAG, 586 (11%) were women and the mean (SD) age was 60 (8.7) years. Of 14 496 participants who underwent LITA+SVG, 2803 (19%) were women and the mean (SD) age was 68 (8.9) years. The median (interquartile range) follow-up time was 9.1 (5.1-12.6) years and 8.1 (4.5-11.7) years for the groups receiving MAG and LITA+SVG, respectively. Compared with LITA+SVG, MAG was associated with reduced mortality rates (hazard ratio [HR], 0.79; 95% CI, 0.72-0.87) and repeated revascularization rates (HR, 0.74; 95% CI, 0.66-0.84) in 15-year follow-up and reduced incidences of myocardial infarction (HR, 0.63; 95% CI, 0.47-0.85) and heart failure (HR, 0.79; 95% CI, 0.64-0.98) in 7-year follow-up. The long-term benefits were coherent by all 3 statistical methods and persisted among patient subgroups with diabetes, obesity, moderately impaired ejection fraction, chronic obstructive pulmonary disease, peripheral vascular disease, or renal disease. Multiple arterial grafting was not associated with increased morbidity or mortality rates at 30 days overall or within patient subgroups.

Conclusions and Relevance

Compared with LITA+SVG, MAG is associated with reduced mortality, repeated revascularization, myocardial infarction, and heart failure among patients with multivessel disease who are undergoing coronary artery bypass grafting without increased mortality or other adverse events at 30 days. The long-term benefits consistently observed across multiple outcomes and subgroups support the consideration of MAG for a broader spectrum of patients who are undergoing coronary artery bypass grafting in routine practice.

The radial artery in coronary surgery, 2018

It is now 25 years since the radial artery (RA) was reintroduced in coronary surgery. It has evolved into being a significant coronary artery bypass conduit and ranks third in usage after the internal thoracic artery (ITA) and saphenous vein grafts (SVG). Its advantages are that it can be readily and efficiently harvested, is of good length and appropriate size for coronary artery bypass graft (CABG) surgery, is robust and easy to handle, and remains free of atheroma, and there is minimal wound morbidity. The RA must be used judiciously with attention to spasm prophylaxis because of its muscular wall, and by avoiding competitive flow. Its patency is equivalent to the ITAs when placed to similar coronary territories and under similar conditions (stenosis, size, quality) and RA patencies are always superior to those of SVG in both observational and randomized studies-88-90% versus 50-60% at 10 years, and 80-87% versus 25-40% at 20 years. Its use and excellent patencies result in survival results equivalent to bilateral internal thoracic artery (BITA) grafting and always superior to left internal thoracic artery (LITA) +SVG. Typical radial artery multiarterial bypass grafting (RA-MABG) 10-year survivals are 80-90% versus 70-80% for LITA-SVG. In general, for every 100 patients undergoing CABG, 10 more patients will be alive at 10 years post-operatively. The RA also is important in achieving total arterial revascularization, and several reports indicate a further survival advantage for patients having three arterial grafts over two. The RAs are especially useful in diabetic, morbidly obese patients, those with conduit shortage, and leg pathology, and in coronary reoperations. Although the RA has equivalent patencies to the right internal thoracic artery (RITA), it is much more versatile. RAs that have been instrumented by angiography or percutaneous coronary intervention should be avoided. The radial artery has proved to be an excellent arterial conduit, is equivalent to but more versatile than the RITA, and is always superior to SVG. Its use should be part of every coronary surgeon's skill set.

Long term outcomes of radial artery grafting in patients undergoing coronary artery bypass surgery

Single arterial left internal thoracic artery (LITA) based coronary artery bypass surgery (LITA-SABG) has been the principal revascularization strategy for over 25 years across all patient demographics. In line with the current emphasis being placed on personalized medicine, which tailors individual, patient-specific therapy to optimize outcomes, coronary artery bypass grafting (CABG) techniques have also evolved to achieve enhanced results among specific groups of patients with coronary artery disease. Most notable has been the development of multi-arterial bypass grafting (MABG) techniques, using either the radial artery (RA) or the right internal thoracic artery (RITA) in conjunction with the LITA, as both techniques have been shown to enhance long term survival of CABG patients. This article reviews the latest data on the long-term outcomes of RA-MABG and considers its impact in various sub-cohorts of CABG that are increasingly being treated by cardiac surgeons. The primary aim of this review is to highlight the advantages of RA-MABG over LITA-SABG and thereby potentiate its adoption into clinical practice. Our secondary aim is to summarize the results of RA-MABG in specific CABG sub-cohorts, to more closely align CABG surgery with the emerging consensus that personalized medicine enhances healthcare value.

Optimal management of radial artery grafts in CABG: Patient and target vessel selection and anti-spasm therapy

The current literature on radial artery grafting is reviewed focusing on the optimal deployment of radial artery grafts in coronary artery bypass surgery with specific attention to the selection of patients and target vessels for radial artery grafting.

Associations Between Adding a Radial Artery Graft to Single and Bilateral Internal Thoracic Artery Grafts and Outcomes: Insights From the Arterial Revascularization Trial

BACKGROUND

Whether the use of the radial artery (RA) can improve clinical outcomes in coronary artery bypass graft surgery remains unclear. The ART (Arterial Revascularization Trial) was designed to compare survival after bilateral internal thoracic artery (BITA) over single left internal thoracic artery (SITA). In the ART, a large proportion of patients (≈20%) also received an RA graft instead of a saphenous vein graft (SVG). We aimed to investigate the associations between using the RA instead of an SVG to supplement SITA or BITA grafts and outcomes by performing a post hoc analysis of the ART.

METHODS

Patients enrolled in the ART (n=3102) were classified on the basis of conduits actually received (as treated). The analysis included 2737 patients who received an RA graft (RA group; n=632) or SVG only (SVG group; n=2105) in addition to SITA or BITA grafts. The primary end point was the composite of myocardial infarction, cardiovascular death, and repeat revascularization at 5 years. Propensity score matching and stratified Cox regression were used to compare the 2 strategies.

RESULTS

Myocardial infarction, cardiovascular death, and repeat revascularization cumulative incidence was 2.3% (95% confidence interval [CI], 1.1-3.4), 3.5% (95% CI, 2.1-5.0), and 4.4% (95% CI, 2.8-6.0) in the RA group and 3.4% (95% CI, 2.0-4.8), 4.0% (95% CI, 2.5-5.6), and 7.6% (95% CI, 5.5-9.7) in the SVG group, respectively. The composite end point was significantly lower in the RA group (8.8%; 95% CI, 6.5-11.0) compared with the SVG group (13.6%; 95% CI, 10.8-16.3; P=0.005). This association was present when an RA graft was used to supplement both SITA and BITA grafts (interaction P=0.62).

CONCLUSIONS

This post hoc ART analysis showed that an additional RA was associated with lower risk for midterm major adverse cardiac events when used to supplement SITA or BITA grafts.

CLINICAL TRIAL REGISTRATION

URL: https://www.situ.ox.ac.uk/surgical-trials/art. Unique identifier: ISRCTN46552265.

The Surgical Treatment of Coronary Artery Occlusive Disease: Modern Treatment Strategies for an Age Old Problem

Coronary artery disease remains a formidable challenge to clinicians. Percutaneous interventions and surgical techniques for myocardial revascularization continue to improve. Concurrently, in light of emerging data, multiple practice guidelines have been published guiding clinicians in their therapeutic decisions. The multidisciplinary Heart Team concept needs to be embraced by all cardiovascular providers to optimize patient outcomes.

The future of off-pump coronary artery bypass grafting: a North American perspective

Off-pump coronary artery bypass graft (OPCAB) is currently performed routinely in a minority of specialized centers and in many more centers, utilized only when a porcelain aorta mandates a no-touch aortic technique. The OPCAB literature can be summarized as follows: (I) large-scale randomized trials in relatively low risk patients that include surgeons with a range of experience demonstrating no consistent beneficial differences in major cardiovascular and cerebrovascular outcomes but lower transfusion rates and shorter length of stay, tempered by some reports of higher rates of incomplete revascularization and lower rates of long term graft patency; (II) smaller randomized controlled trials (RCTs) from highly specialized programs demonstrating equivalent or superior outcomes with OPCAB and similar completeness of revascularization and graft patency; and (III) observational data from large databases demonstrating a consistent benefit of OPCAB, especially in higher-risk patient subsets. Our rationale for OPCAB remains that if complete and precise revascularization can be safely and routinely accomplished, then the patient should benefit by avoiding the morbidities that can be attributed to aortic cannulation/clamping, cardiopulmonary bypass (CPB), hemodilution, hypothermia and global myocardial ischemia/cardioplegia. We further believe that OPCAB procedures should emphasize the use of arterial grafts to optimize long term patency and minimize aortic manipulation to limit the risk of stroke. Moving forward, the off-pump surgical community and specialty societies must address the challenge of training surgeons and their teams to master this technically demanding procedure. Furthermore, OPCAB opens the door to minimally-invasive surgical revascularization via hybrid coronary revascularization (HCR). A large NIH-funded RCT is currently underway to determine whether hybrid revascularization can offer a superior alternative to multi-vessel percutaneous coronary intervention for patients with low SYNTAX score and proximal LAD disease.

Advanced glycation end products impair the functions of saphenous vein but not thoracic artery smooth muscle cells through RAGE/MAPK signalling pathway in diabetes

Saphenous vein (SV) and internal thoracic artery (ITA) are commonly used bypass conduits. However, graft failure occurs in SV rather than in ITA, especially in diabetes (DM). The mechanism for this difference has not been fully understood. Accumulation of advanced glycation end products (AGEs) and activation of AGEs receptor (RAGE) could accelerate smooth muscle cells (SMC) proliferation in DM, we thus asked whether AGEs-RAGE could mediate the differences between SMC from SV (SMCV ) and from ITA (SMCA ). Twenty-five patients with DM and other 25 patients without DM were enclosed in DM and control group, respectively. AGEs (100 μg/ml) were added to cultured SMCA and SMCV obtained at coronary artery bypass graft (CABG) and proliferative rates were determined. Transcript expression, phosphorylation or protein expression levels of MAP kinase family (ERK, p38 and JNK), matrix metalloproteinases (MMP)-2 and MMP-9 were analysed by real-time PCR, Western-blot or immunofluorescence staining, respectively. Compared with paired SMCA , SMCV showed significantly increased proliferation rate, MAP kinase family phosphorylation, and MMP-2/9 expression in both groups, especially in DM group. The responses of SMCV induced by AGEs were significantly larger in DM than in control group, which could be suppressed by inhibition of RAGE and ERK. However, all the cellular events of SMCV were not found in paired SMCA . This study suggests that AGEs-RAGE could induce the proliferation of SMCV but not SMCA via MAP kinase pathway in DM. It is the intrinsic 'inactive' tendency of SMCA that contributes to the different rates of graft disease between SV and ITA after CABG.

CABG Versus PCI: Greater Benefit in Long-Term Outcomes With Multiple Arterial Bypass Grafting

BACKGROUND

Treatment of multivessel coronary artery disease with traditional single-arterial coronary artery bypass graft (SA-CABG) has been associated with superior intermediate-term survival and reintervention compared with percutaneous coronary intervention (PCI) using either bare-metal stents (BMS) or drug-eluting stents (DES).

OBJECTIVES

This study sought to investigate longer-term outcomes including the potential added advantage of multiarterial coronary artery bypass graft (MA-CABG).

METHODS

We studied 8,402 single-institution, primary revascularization, multivessel coronary artery disease patients: 2,207 BMS-PCI (age 66.6 ± 11.9 years); 2,381 DES-PCI (age 65.9 ± 11.7 years); 2,289 SA-CABG (age 69.3 ± 9.0 years); and 1,525 MA-CABG (age 58.3 ± 8.7 years). Patients with myocardial infarction within 24 h, shock, or left main stents were excluded. Kaplan-Meier analysis and Cox regression were used to separately compare 9-year all-cause mortality and unplanned reintervention for BMS-PCI and DES-PCI to respective propensity-matched SA-CABG and MA-CABG cohorts.

RESULTS

BMS-PCI was associated with worse survival than SA-CABG, especially from 0 to 7 years (p = 0.015) and to a greater extent than MA-CABG was (9-year follow-up: 76.3% vs. 86.9%; p < 0.001). The surgery-to-BMS-PCI hazard ratios (HR) were as follows: versus SA-CABG, HR: 0.87; and versus MA-CABG, HR: 0.38. DES-PCI showed similar survival to SA-CABG except for a modest 0 to 3 years surgery advantage (HR: 1.06; p = 0.615). Compared with MA-CABG, DES-PCI exhibited worse survival at 5 (86.3% vs. 95.6%) and 9 (82.8% vs. 89.8%) years (HR: 0.45; p <0.001). Reintervention was substantially worse with PCI for all comparisons (all p <0.001).

CONCLUSIONS

Multiarterial surgical revascularization, compared with either BMS-PCI or DES-PCI, resulted in substantially enhanced death and reintervention-free survival. Accordingly, MA-CABG represents the optimal therapy for multivessel coronary artery disease and should be enthusiastically adopted by multidisciplinary heart teams as the best evidence-based therapy.

A mechanical argument for the differential performance of coronary artery grafts

Coronary artery bypass grafting (CABG) acutely disturbs the homeostatic state of the transplanted vessel making retention of graft patency dependent on chronic remodeling processes. The time course and extent to which remodeling restores vessel homeostasis will depend, in part, on the nature and magnitude of the mechanical disturbances induced upon transplantation. In this investigation, biaxial mechanical testing and histology were performed on the porcine left anterior descending artery (LAD) and analogs of common autografts, including the internal thoracic artery (ITA), radial artery (RA), great saphenous vein (GSV) and lateral saphenous vein (LSV). Experimental data were used to quantify the parameters of a structure-based constitutive model enabling prediction of the acute vessel mechanical response pre-transplantation and under coronary loading conditions. A novel metric Ξ was developed to quantify mechanical differences between each graft vessel in situ and the LAD in situ, while a second metric Ω compares the graft vessels in situ to their state under coronary loading. The relative values of these metrics among candidate autograft sources are consistent with vessel-specific variations in CABG clinical success rates with the ITA as the superior and GSV the inferior graft choices based on mechanical performance. This approach can be used to evaluate other candidate tissues for grafting or to aid in the development of synthetic and tissue engineered alternatives.

Are all forms of total arterial revascularization equal? A comparison of single versus bilateral internal thoracic artery grafting strategies

OBJECTIVE

Total arterial revascularization (TAR) with internal thoracic arteries (ITAs) and radial arteries (RA) is associated with greater long-term survival compared with the use of a single internal thoracic artery supplemented by veins. The optimal conduit choice and configuration in achieving TAR remains controversial, with uncertainty regarding the individual prognostic impact of ITAs and RAs. As such, among patients solely undergoing TAR, we compared long-term survival between patients receiving single thoracic arteries and those receiving bilateral ITAs.

METHODS

From 1995 to 2010, 2821 patients with 3-vessel coronary artery disease at 8 centers underwent primary isolated coronary artery bypass with TAR using ITAs and RAs. Bilateral ITAs were used in 912 patients. In 380 cases, bilateral in situ ITAs were grafted to the left coronary system. RAs were used in 848 patients (93%) receiving bilateral ITAs and 1906 patients (99.8%) receiving single ITAs. Survival data were obtained using the National Death Index. Separate 1:1 propensity score-matched analyses were performed for (1) bilateral ITA versus single ITA and (2) bilateral ITA incorporating a free right ITA versus single ITA and RAs. Among the 912 patients with bilateral ITAs, those receiving an in situ right ITA to the left coronary system were compared with those receiving a free right ITA.

RESULTS

In the propensity score-matched analysis comparing bilateral versus single ITAs (591 matched pairs), there were similar rates of 30-day mortality and deep sternal wound infection. Bilateral ITA use was associated with greater 15-year survival (79% ± 3.9% vs 67% ± 4.7%, P < .001). In the analysis between bilateral ITA incorporating a free right ITA versus single ITA + RAs (380 matched pairs), bilateral ITA use demonstrated comparable survival at 15 years (79% ± 4.7% vs 67% ± 5.7%, P = .09). Among patients receiving bilateral ITAs, comparison between in situ right ITA versus free right ITA recipients (206 matched pairs) revealed comparable 15-year survival (84% ± 6.1% vs 79% ± 6.7%, P = .13). Multivariable Cox regression found bilateral ITA use to be protective from mortality (hazard ratio, 0.73; 95% confidence interval, 0.59-0.90, P = .004).

CONCLUSIONS

The use of bilateral ITAs as an in situ or free conduit is associated with greater survival and seems to offer a prognostic advantage over the use of only a single ITA supplemented by RAs. Therefore, all configurations of TAR are not equivalent.

Multi Versus Single Arterial Coronary Bypass Graft Surgery Across the Ejection Fraction Spectrum

BACKGROUND

Left internal thoracic artery (LITA) and radial artery (RA) multi-arterial CABG (MABG) is generally associated with improved long-term survival compared with traditional LITA and saphenous vein single arterial CABG (SABG). We examined the hypothesis that this multi-arterial survival advantage persists irrespective of left ventricular ejection fraction (LVEF).

METHODS

We retrospectively analyzed the primary, non-salvage multi-graft CABG experience (n = 11,261; 64.4 ± 10.4 years, 70.4% men) from 2 institutions (1995 to 2011). Risk-adjusted 15-year survival was pairwise compared for the MABG versus SABG grafting approaches within 3 LVEF subcohorts (>0.50, n = 4,833 [44% MABG]; 0.36 to 0.50, n = 4,465 [39% MABG]; and ≤ 0.35, n = 1,963 [35% MABG]) using propensity-matched and covariate adjusted Cox regression (all patients) comparisons.

RESULTS

Propensity matching yielded 1,317 (LVEF > 0.50), 1,179 (LVEF, 0.36 to 0.50), and 470 (LVEF ≤ 0.35) well-matched grafting method pairs. Acute perioperative mortality was equivalent between MABG and SABG within each LVEF group, but increased with decreasing LVEF. MABG was uniformly associated with better 15-year survival compared with SABG for all LVEF categories. The associated matched-adjusted hazard ratios (95% confidence intervals) were consistent across EF groups at 0.79 (0.68 to 0.93), 0.80 (0.69 to 0.93), and 0.82 (0.66 to 1.0), respectively. Covariate adjusted HR in all patients concurred with matched results.

CONCLUSIONS

MABG results in significantly enhanced long-term survival compared with LITA/SVG SABG regardless of the degree of LV dysfunction. These results favor MABG as the therapy of choice in patients with LV dysfunction.