Philip Hayward

Comparable patencies of the radial artery and right internal thoracic artery or saphenous vein beyond 5 years: results from the Radial Artery Patency and Clinical Outcomes trial.

OBJECTIVE To investigate the optimum conduit for coronary targets other than the left anterior descending artery, we evaluated long-term patencies and clinical outcomes of the radial artery, right internal thoracic artery, and saphenous vein through the Radial Artery Patency and Clinical Outcomes trial. METHODS As part of a 10-year prospective, randomized, single-center trial, patients undergoing primary coronary surgery were allocated to the radial artery (n = 198) or free right internal thoracic artery (n = 196) if aged less than 70 years (group 1), or radial artery (n = 113) or saphenous vein (n = 112) if aged at least 70 years (group 2). All patients received a left internal thoracic artery to the left anterior descending, and the randomized conduit was used to graft the second largest target. Protocol-directed angiography has been performed at randomly assigned intervals, weighted toward the end of the study period. Grafts are defined as failed if there was occlusion, string sign, or greater than 80% stenosis, independently reported by 3 assessors. Analysis is by intention to treat. RESULTS At mean follow up of 5.5 years, protocol angiography has been performed in groups 1 and 2 in 237 and 113 patients, respectively. There are no significant differences within each group in preoperative comorbidity, age, or urgency. Patencies were similar for either of the 2 conduits in each group (log rank analysis, P = .06 and P = .54, respectively). The differences in estimated 5-year patencies were 6.6% (radial minus right internal thoracic artery) in group 1 and 2.9% (radial minus saphenous vein graft) in group 2. CONCLUSION At mean 5-year angiography in largely asymptomatic patients, the selection of arterial or venous conduit for the second graft has not significantly affected patency. This finding offers surgeons, for now, enhanced flexibility in planning revascularization.

Total arterial revascularization with internal thoracic and radial artery grafts in triple-vessel coronary artery disease is associated with improved survival.

OBJECTIVES We sought to evaluate our experience with total arterial revascularization and compare it with the traditional approach of a single internal thoracic artery supplemented by saphenous veins. METHODS From 1995 to 2010, 6059 patients with triple-vessel coronary artery disease underwent primary isolated coronary artery bypass grafting at 8 centers. A study cohort of 3774 patients was formed, with 2988 (79%) undergoing total arterial revascularization and 786 (21%) receiving only saphenous veins to supplement a single in situ internal thoracic artery. In the total arterial revascularization group, bilateral internal thoracic arteries were used in 1079 patients (36%) and at least 1 radial artery was used in 2916 patients (97%). Propensity score matching was used for risk adjustment. RESULTS Patients undergoing total arterial revascularization were younger (65.0±10.4 years vs 71.3±7.9 years, P<.001) and less likely to have diabetes, cerebrovascular disease, recent myocardial infarction, and severe left ventricular impairment. At 15 years, patients who underwent total arterial revascularization experienced superior unadjusted survival (62%±1.1% vs 35%±1.9%, P<.001). Multivariable Cox regression in the entire study cohort showed the total arterial group had improved survival with a hazard ratio of 0.79 (95% confidence interval, 0.70-0.90; P<.001). After propensity score matching yielded 384 patient pairs, patients who underwent total arterial revascularization showed improved survival at 15 years than patients who underwent single arterial revascularization (54%±3.3% vs 41%±3.0%, P=.0004). CONCLUSIONS This large multicenter study suggests that a strategy of total arterial revascularization is associated with improved long-term survival compared with the use of only a single arterial and saphenous vein grafts. Total arterial revascularization should be encouraged in patients with a reasonable life expectancy.

Choice of conduits for coronary artery bypass grafting: craft or science?

Long-term patency of a bypass graft is an important determinant in reducing morbidity and increasing survival after coronary bypass surgery. The purpose of this review is to analyse factors contributing to improved outcomes of commonly used conduits. Progress has been limited by the lack of uniform definitions of graft failure and development of appropriate statistical models. Evolving techniques for assessing patency at more frequent intervals has provided insight into the time and sites of early disease. The explosion of scientific knowledge of graft physiology has added to improving harvest, storage and early protection procedures thereby reducing early morbidity. Similarly, the understanding and management of risk factors have contributed to graft durability and possibly survival. Conduits have different characteristics and applications, which are patient dependent. Competitive flow remains a problem especially with arterial conduits; functional studies as opposed to anatomy of the target artery may improve understanding of the contribution of the collateral circulation. Selected patency data provide comparison between grafts. The role of the second internal thoracic artery graft is the subject of the Arterial Revascularisation Trial. Off-pump bypass procedures and patient characteristics affect conduit selection. Stroke is a major complication, which can be minimised by avoiding the aorta especially during off-pump surgery. There are few randomised controlled trials on the late outcomes comparing different bypass grafts and between bypass grafting and current percutaneous intervention methods. Accurate reporting of outcomes of graft patency will improve the scientific content and emphasise the importance of surgery in the management of coronary disease.

Effect of radial artery or saphenous vein conduit for the second graft on 6-year clinical outcome after coronary artery bypass grafting. Results of a randomised trial

OBJECTIVES In order to determine the best conduit for coronary targets other than the left anterior descending (LAD) artery, long-term clinical outcomes following revascularisation with a radial artery or saphenous vein graft were evaluated as part of the radial artery patency and clinical outcomes (RAPCO) study. METHODS As part of the RAPCO protocol for this prospective, randomised, single-centre trial, patients aged over 70 years undergoing primary CABG were randomly assigned to use of a radial artery (n=113) or saphenous vein (n=112) to revascularise the best non-LAD coronary vessel. Follow-up was annual. Primary clinical end-points were death, myocardial infarction or need for revascularisation. Data were analysed by intention to treat. RESULTS The preoperative demographics (age, gender, presence of hypertension or diabetes mellitus) and urgency of surgery did not differ significantly between the two groups. The allocated arterial or venous conduit was utilised as intended in 104/113 and 110/112 patients, respectively. Mean number of grafts was 3.2+/-0.9 and 3.3+/-0.7 in the two groups. During follow-up of mean duration 6.2 years (maximum 10.8 years) there were 16 deaths in each group and 9 vs 13 other events in the radial artery and saphenous vein groups, respectively. These clinical outcomes did not differ significantly (log rank p=0.98 for survival and p=0.52 for event-free survival). CONCLUSIONS Use of a radial artery or saphenous vein for the second graft during primary CABG does not significantly influence clinical outcome at 6 years. Mean 5-year angiographic patency data are awaited, but from the patients perspective the likelihood of a satisfactory long-term result is equivalent, whichever conduit is used.

Choice of Conduit for the Right Coronary System: 8-Year Analysis of Radial Artery Patency and Clinical Outcomes Trial

BACKGROUND Previous reports have supported the use of bilateral internal thoracic arteries to revascularize the left coronary circulation. If this becomes standardized practice, the optimal conduit for the right coronary system remains to be established. Our objective is to compare the performance of the radial artery versus the saphenous vein when used to graft the right coronary artery or its branches during an 8-year period after primary coronary artery bypass graft surgery. METHODS The Radial Artery Patency and Clinical Outcomes study is a randomized controlled trial comparing radial artery, saphenous vein, and free right internal thoracic artery. Of the 621 patients enrolled in the study, 465 patients received a graft to the right coronary artery or its branches. The retrospectively compiled database was used to establish patency rates and clinical events among these patients. RESULTS Absolute graft patency rates were as follows: radial artery, 86.9% of 68 (95% confidence interval, 76.6% to 93.1%); and saphenous vein, 81.2% of 197 (95% confidence interval, 75.1% to 86.1%). Noninferiority tests show that absolute radial patency to saphenous patency is at least 0.9526 (p = 0.025). Kaplan-Meier estimates of angiographic outcomes show no significant difference (log rank p = 0.22). Cardiac events in the right coronary territory occurred in the radial artery group (1.79%) versus the saphenous vein group (4.93%; p = 0.26). Overall mortality was 8.03% in the radial artery group versus 12.5% in the saphenous vein group (p = 0.23). CONCLUSIONS The radial artery patency is at least comparable to that of the saphenous vein when grafted to the right coronary artery or its branches. The paucity of clinical events in both grafts is notable. Selection of best conduit may therefore be made according to other factors.

The Radial Artery Patency and Clinical Outcomes Trial: Design, Intermediate Term Results and Future Direction

The Radial Artery Patency and Clinical Outcomes Study (RAPCO) was devised and implemented in Melbourne in order to establish the appropriate place of the radial artery in the hierarchy of conduits available to the modern coronary bypass surgeon. Designed as a biological comparison with minimisation of other confounding variables, it compares this free arterial graft with the right internal thoracic artery and saphenous vein, with all conduits used in an identical fashion in two parallel cohorts of different age ranges. Enrolment was completed in 2004 and 10-year follow-up is in progress, with mean duration of about seven years at present. The midterm clinical and angiographic results to date are reviewed here, but definitive conclusions will not be possible until full completion angiographic data is available. The trial data provides a number of potential substudies of conduits, risk factors for failure and the natural history of treated coronary disease.

Custodiol versus blood cardioplegia in complex cardiac operations: an Australian experience

OBJECTIVES A single or dual-dose strategy for myocardial protection is attractive in long operations, in avoiding the need to interrupt the procedure to re-administer cardioplegia. We hypothesized that a single administration of Bretschneider histidine-tryptophan-ketoglutarate (HTK) crystalloid solution (Custodiol) offers myocardial protection comparable with repeated tepid blood cardioplegia. METHODS We reviewed a prospectively compiled single-centre database containing all adult cardiac procedures performed from January 2005 to January 2011. Preoperative demographic and investigative data, operative variables and postoperative (30-day) mortality and morbidity were compared between the Custodiol and blood cardioplegia groups. The study primary endpoints were 30-day mortality, return to the operating theatre, myocardial infarction, stroke, postoperative requirement for an intra-aortic balloon pump, new renal failure, prolonged ventilation and re-admission to hospital within 30 days. Propensity score matching was performed to correct for any bias that may have been associated with the usage of Custodiol. RESULTS A total of 1900 cardiac surgical procedures were identified of which 126 (7%) utilized Custodiol and 1774 (93%) used blood cardioplegia as the primary cardioplegic agent. After propensity-score matching, we were able to match 71 Custodiol cases one-to-one to those receiving blood cardioplegia. There were no statistically significant differences noted for any of the endpoints studied after propensity-score matching. In particular, the proportion of mortality (blood cardioplegia: 1 vs Custodiol 4%, P = 0.63) any mortality/morbidity (blood cardioplegia: 35 vs Custodiol: 39% P = 0.46) was similar between the groups. CONCLUSIONS The use of Custodiol is convenient, simple and at least as safe as tepid blood cardioplegia for myocardial protection in complex cardiac operations. A randomized prospective comparison of myocardial protection strategies is warranted.

Mid-term results of the Radial Artery Patency and Clinical Outcomes randomized trial

BACKGROUND The radial artery (RA), as an alternative to the saphenous vein or the right internal thoracic artery (RITA) for coronary artery bypass grafting, has gained considerable interest over the years. A randomized controlled trial was undertaken to assess the suitability of the radial artery as a conduit. METHOD The Radial Artery Patency and Clinical Outcomes (RAPCO) trial is a double-armed randomized controlled trial comparing the RA with the free RITA in a younger cohort of patients undergoing elective coronary bypass surgery, and the RA with the saphenous vein in an older group. The trial conduit was grafted to the most important coronary target after the left anterior descending artery, which received the gold standard left internal thoracic artery. Clinical outcomes and angiographic patency up to 10 years was recorded during careful follow up, with annual clinical review and a program of randomly assigned, staggered angiography. The final trial results will be available in 2014. RESULTS Mid-trial results have shown equivalent survival and event-free survival and graft patency in both arms at median follow up of approximately 6 years. The demographic and clinical data, pre- and postoperative angiographic findings of the trial database have led to a number of substudies focusing on the role of lipid exposure in patency and disease progression, the fate of moderate lesions when grafted or left alone, patterns of disease regression, and patient satisfaction with graft harvest sites. CONCLUSIONS While the final analysis of the primary trial end points is eagerly awaited, the additional insight into the natural history of grafted coronary artery disease with modern secondary prevention will be of considerable interest.

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.

The art of arterial revascularization—total arterial revascularization in patients with triple vessel coronary artery disease

The use of the left internal thoracic artery to graft the left anterior descending artery has been widely accepted as the gold standard for surgical treatment of coronary disease for over 40 years. However the use of multiple other arterial grafts to support this has not been accepted readily, in spite of evidence of superiority over saphenous vein grafts, probably because of perceptions of technical complexity, time constraints for conduit harvesting and increased peri-operative complications. As a result, even today most patients with multivessel coronary artery disease do not receive the potential benefits of extensive or total arterial revascularization. We discuss here the use of contemporary techniques and grafts configurations to simplify this, and the safety and benefit data underpinning this practice. Current patency data confirm that a left internal thoracic artery graft performs well beyond 20 years, with over 80% freedom from failure, but accumulating data suggest that the right internal thoracic artery behaves in the same way. Radial artery grafts are being studied in several randomized trials, but observational studies already suggest a performance which compares favourably with saphenous vein. Total arterial revascularization is achievable in most patients with a small but acceptable increase in risk of sternal complications when certain defined subgroups are excluded.