Current Readings: Single vs Bilateral Internal Mammary Artery in Coronary Artery Bypass Grafting.

There is strong retrospective data demonstrating that bilateral internal mammary artery (BIMA) grafting leads to better long-term survival as compared to left internal mammary artery grafting. However, this survival advantage was not corroborated by the interim results of the Arterial Revascularization Trial. Today, there are barriers to widespread adoption of BIMA grafting. One of the main disadvantages of the use of BIMA grafts is the higher risk of deep sternal wound infection. Deep sternal wound infections can be minimized by skeletonized harvesting of the internal mammary artery grafts, which preserve blood flow to the sternum. Also, utilizing the BIMA graft as a "Y" graft may lead to more complete revascularization compared to its in situ use. BIMA grafting on average takes 25 minutes longer operating time with a higher in-hospital costs. We eagerly await the 10-year results of the Arterial Revascularization Trial to determine the truly unbiased randomized long-term effectiveness of BIMA grafting.

One-year costs of bilateral or single internal mammary grafts in the Arterial Revascularisation Trial.

OBJECTIVE: Coronary artery bypass grafting (CABG) using bilateral internal mammary arteries (BIMA) may improve survival over CABG using single internal mammary arteries (SIMA), but may be surgically more complex (and therefore costly) and associated with impaired sternal wound healing. We report, for the first time, a detailed comparison of healthcare resource use and costs over 12 months, as part of the Arterial Revascularisation (ART) Trial. METHODS: 3102 patients in 28 hospitals in seven countries were randomised to CABG surgery using BIMA (n=1548) or SIMA (n=1554). Detailed resource use data were collected covering surgery, the initial hospital episode, and for 12 months post randomisation. Using UK unit costs, total costs were calculated and compared between trial arms and for subgroups. RESULTS: Patients randomised to BIMA spent 20 min longer in theatre (95% CI 15 to 25, p<0.001) and also required more treatment for sternal wound problems. Mean (SD) total costs per patient at 12 months were £13 839 (£10 534) for BIMA and £12 717 (£9719) for SIMA (mean cost difference £1122, 95% CI £407 to £1838, p=0.002). No tests for interaction between subgroups and treatment allocation were significant. CONCLUSIONS: At 12 months from randomisation, mean costs were approximately 9% higher in BIMA than SIMA patients, primarily due to longer time in theatre and in-hospital stay, and slightly higher costs related to sternal wound problems during follow-up. Follow-up to the primary trial endpoint of 10 years will reveal whether longer-term differences emerge in graft patency or in overall survival. TRIAL REGISTRATION NUMBER: Controlled-trials.com (ISRCTN46552265).

Short-term clinical outcomes after hybrid coronary revascularization versus off-pump coronary artery bypass for the treatment of multivessel or left main coronary artery disease: a meta-analysis.

BACKGROUND: Hybrid coronary revascularization (HCR) and off-pump coronary artery bypass grafting (OPCABG) are both feasible, less invasive techniques for coronary revascularization. Although both techniques utilize the left internal mammary artery to left anterior descending artery graft, HCR uses drug-eluting stents instead of saphenous vein bypass. It remains unclear whether HCR is equal to, better or worse than OPCABG. METHODS AND RESULTS: A meta-analysis was carried out using a random-effects model. Seven observational studies were included. There was no significant difference either in in-hospital mortality [relative risk (RR) 0.57, 95% confidence interval (CI) 0.13-2.59, P=0.47] or in the MACCE rate (RR 0.63, 95% CI 0.24-1.64, P=0.34) between the HCR group and the OPCABG group. A significant difference was observed between the two groups in the length of hospitalization (RR 0.55, 95% CI 0.13-0.97, P=0.01), length of ICU stay (RR 0.45, 95% CI 0.10-0.80, P<0.05), intubation time (RR 0.48, 95% CI 0.13-0.84, P<0.01), need for red blood transfusion (RR 0.67, 95% CI 0.56-0.82, P<0.001), and total in-hospital costs (RR 0.90, 95% CI 0.39-1.42, P<0.01). CONCLUSION: Compared with OPCABG, HCR did not improve early survival but decreased the length of hospitalization, length of ICU stay, intubation time, and need for red blood transfusion, and increased total in-hospitalcosts.

The impact of hybrid coronary revascularization on hospital costs and reimbursements.

BACKGROUND: Hybrid coronary revascularization (HCR) combines a minimally invasive, left internal mammary artery-left anterior descending coronary artery (LAD) bypass with percutaneous intervention of non-LAD vessels for patients with multivessel coronary disease. The financial implications of HCR have not been compared with off-pump coronary artery bypass (OPCAB) through sternotomy. METHODS: The contribution margin is a fiduciary calculation (best hospital payment estimate--total variable costs) used by hospitals to determine fiscal viability of services. From 2010 to 2011, 26 Medicare patients underwent HCR at a single United States institution and were compared with 28 randomly selected, contemporaneous Medicare patients undergoing multivessel OPCAB. All HCR patients underwent a robotic-assisted, sternal-sparing, off-pump, left internal mammary artery-LAD anastomosis plus percutaneous intervention to non-LAD vessels. A linear regression model was used to compare fiscal and utilization outcomes of HCR to OPCAB adjusted for hospital length of stay and The Society of Thoracic Surgeons Predicted Risk of Mortality score. RESULTS: On regression analysis controlling for overall length of stay and Predicted Risk of Mortality score, the contribution margin (+$8,771, p<0.0001) was greater for HCR than for OPCAB. Despite higher total cost for HCR compared with OPCAB (+$7,026, p=0.001), the total variable cost (+$2,281, p=0.07) was not significantly different. Best payment estimates (+11,031, p<0.0001) and Medicare reimbursements (+$8,992, p=0.002) were higher for HCR than for OPCAB, and there was a reduction in blood transfusion (-1.5 units, p<0.0001), ventilator time (-10 hours, p=0.001), and postoperative length of stay (-1.2 days, p=0.002) for the HCR group. CONCLUSIONS: Compared with OPCAB, HCR results in a greater contribution margin for hospitals. This may result from higher reimbursement as well as improved resource utilization postoperatively, which may offset more expensive procedural costs associated with HCR.

Five years follow-up after Y-graft arterial revascularization: on pump versus off pump; prospective clinical trial.

OBJECTIVES: We report our comparative experience of on-pump and off-pump full arterial coronary artery bypass grafting (CABG) using both internal mammary arteries (IMAs) anastomosed as a Y-graft. METHODS: A single-center clinical study was conducted prospectively between January 2003 and May 2008. It compared the short- and mid-term clinical outcomes of on- and off-pump arterial revascularization where the left internal mammary artery (LIMA) was anastomosed to the left anterior descending (LAD) artery while the free right internal mammary artery (RIMA) graft taking off from the LIMA was used to bypass different coronary targets. RESULTS: One hundred and ninety-two patients were divided into 77 on-pump and 115 off-pump procedures based on the intention to treat. The mean age in both groups was 60.2+/-11.7 and 68.1+/-10.6 years, respectively (P<0.05). Mean predictive logistic EuroSCORE was 3.5+/-6.7% for the on-pump group and 7.3+/-8.6% for the off-pump group (P<0.0001). Mean number of distal anastomoses were 2.7+/-0.6 (group ON) and 2.5+/-0.6 (group OFF) (P=NS). Postoperative mortality was two patients (2.6%) in the on-pump group and four patients (3.4%) in the off-pump group (P=0.63). No major adverse cardiac event, no stroke and no late death were reported during the follow-up that averaged 36.5+/-18.6 months. Angina recurrence was three patients (2.6%) in off-pump and two patients (3.5%) in on-pump group (P=NS). CONCLUSIONS: The use of a free RIMA as Y-graft from the LIMA performed off pump eradicates aortic manipulations and provides complete revascularization to high-risk patients with mortality similar to the one of a lower risk population operated on pump. The morbidity and cost was lower in the off-pump group. This advocates for the widespread usage of the technique in high-risk patients.

Cost effectiveness analysis of minimally invasive internal thoracic artery bypass versus percutaneous revascularisation for isolated lesions of the left anterior descending artery.

OBJECTIVE: To compare the cost effectiveness of percutaneous transluminal coronary artery stenting with minimally invasive internal thoracic artery bypass for isolated lesions of the left anterior descending artery. DESIGN: Cost effectiveness analysis. DATA SOURCES: Embase, Medline, Cochrane, Google Scholar, and Health Technology Assessment databases (1966-2005), and reference sources for utility values and economical variables. METHODS: Decision analytical modelling and Markov simulation were used to model medium and long term costs, quality of life, and cost effectiveness after either intervention using data from referenced sources. Probabilistic sensitivity and alternative analyses were used to investigate the effect of uncertainty about the value of model variables and model structure. RESULTS: Stenting was the dominant strategy in the first two years, being both more effective and less costly than bypass surgery. In the third year bypass surgery still remained more expensive but became marginally more effective. As the incremental cost effectiveness was 1,108,130.40 pounds sterling (1 682,146.00 euros; $2,179,194) per quality adjusted life year (QALY), the additional effectiveness could not be said to justify the additional cost at this stage. By five years, however, the incremental cost effectiveness ratio of 28,042.95 pounds sterling per QALY began to compare favourably with other interventions. At 10 years the additional effectiveness of 0.132 QALYs (range -0.166 to 0.430) probably justified the additional cost of 829.02 pounds sterling (range 205.56 pounds sterling to 1452.48 pounds sterling), with an incremental cost effectiveness of 6274.02 pounds sterling per QALY. Sensitivity and alternative analysis showed the results were sensitive to the time horizon and stent type. CONCLUSIONS: Minimally invasive left internal thoracic artery bypass may be a more cost effective medium and long term alternative to percutaneous transluminal coronary artery stenting.

A cost comparison of off-pump CABG versus on-pump CABG at one-year: The Canadian off-pump CABG registry.

BACKGROUND: Evidence suggests that off-pump coronary artery bypass graft surgery (CABG) is as safe and effective as on-pump CABG, and the cost of initial hospitalization for off-pump CABG is less expensive than on-pump CABG. However, it is uncertain whether the cost savings are sustained over a longer period of time. OBJECTIVE: To assess in-hospital and one-year direct medical costs of off-pump CABG versus on-pump CABG in the context of the Canadian health care system. METHODS AND RESULTS: From March 2001 to December 2002, 1657 consecutive patients enrolled in the Canadian Off-Pump CABG Registry were compared with 1693 consecutive on-pump patients from Hamilton Health Sciences CABG database. At one year, patients of both groups were followed by telephone interview. An economic analysis was conducted from the perspective of the Ontario Ministry of Health and Long-Term Care, and the data analysis was based on propensity score-matched registry patients (1233 pairs) to ensure the comparability of the two study groups. Clinical event and resource use information was collected from all patients. Unit costs from the Hamilton Health Sciences case-costing system were used to estimate hospital costs; all costs were reported in 2003 Canadian dollars. Sensitivity analyses were performed to account for uncertainties. The cost of initial hospitalization for off-pump CABG was significantly less than on-pump CABG (11,744 dollars versus 13,720 dollars, P < 0.001). Although follow-up costs were similar between the groups, the one-year total cost per patient for off-pump CABG remained significantly less than on-pump CABG (12,063 dollars versus 14,141 dollars, P < 0.001). CONCLUSION: Off-pump CABG offers significant savings during initial hospitalization that are also sustained after one year.

Morbidity, cost, and six-month outcome of minimally invasive direct coronary artery bypass grafting.

BACKGROUND: Minimally invasive direct coronary artery bypass grafting (MIDCABG) promises to reduce the morbidity of coronary bypass, but this has not been proved. METHODS: This retrospective study compares the morbidity, mortality, cost, and 6-month outcome of patients less than 80 years old undergoing elective left internal mammary artery to left anterior descending artery bypass grafting via MIDCABG (n = 60) or sternotomy (n = 55) between January 1995 and December 1996. There were no differences between the groups in mean age, sex distribution, or preoperative risk level. The left internal mammary artery was mobilized from the fifth costal cartilage to the subclavian artery in all patients. The anastomoses were done with a beating heart in the MIDCABG group and with cardioplegic arrest in the sternotomy group. RESULTS: There were no operative deaths in either group. The MIDCABG patients had a lower transfusion incidence (10/60 [17%] versus 22/55 [40%]; p< or =0.02) and a shorter postoperative intubation time (2.1+/-4.2 versus 12.6+/-9 hours; p< or =0.0001). One patient in each group was reexplored for bleeding. Three sternotomy patients (3/55, 5%) required ventilatory support for greater than 48 hours, but no MIDCABG patient was ventilated for more than 24 hours. Median postoperative length of stay was 4 days for MIDCABG and 7 days for sternotomy. Estimated hospital costs were $11,200+/-3100 for MIDCABG and $15,600+/-4200 for CABG (p < 0.001). The reduced morbidity and cost of MIDCABG was found mostly in high-risk patients. At 6-month follow-up, 5 MIDCABG patients (5/60, 8%) had evidence of recurrent ischemia involving the left anterior descending artery, primarily the result of anastomotic stricture. CONCLUSIONS: This analysis shows that MIDCABG reduces the initial morbidity and cost of coronary bypass, but some patients require subsequent reintervention. Long-term follow-up is needed before MIDCABG can be judged better than traditional bypass, but the initial results are promising, especially in high-risk patients.

Does arterial revascularization decrease the risk of infarction after coronary artery bypass grafting?

BACKGROUND: This study sought to determine whether extensive arterial grafting reduces the prevalence and consequences of infarct after coronary artery bypass grafting. METHODS: Post-primary coronary artery bypass grafting infarcts and time-related events thereafter were identified by 99.9% complete follow-up of 9,600 patients (1971 to 1992). The contribution of arterial grafting to freedom from infarct was assessed by multivariable hazard function analysis to adjust for other risk factors. RESULTS: Unadjusted 1-month and 10-year freedom from infarction was 97% and 86%. By multivariable analysis, arterial grafting lowered the prevalence of periprocedural (p = 0.005), intermediate term (p = 0.007 and 0.006), and late infarction (arterial grafting to the left anterior descending coronary artery, p = 0.0006). Unadjusted survival after first infarct after coronary artery bypass grafting was 74% and 52% at 1 and 10 years; arterial grafting improved 10-year survival from 48% to 59% (p = 0.002). An additional benefit or cost of extending arterial grafting (n = 1,727) beyond a single one could not be identified (p > 0.1). CONCLUSIONS: Arterial conduits, particularly to the left anterior descending coronary artery, should be used for coronary artery bypass grafting to reduce early and late myocardial infarction and its consequences. However, use of more than a single arterial graft appears to confer no additional benefit.

Bilateral mammary artery surgery or percutaneous transluminal coronary angioplasty for multivessel coronary artery disease? An analysis of effects and costs.

Seventy-two patients with stable or unstable angina treated since 1983 by multivessel-PTCA(MVP) were retrospectively compared with 44 similar patients that were suitable for MVP, but who had undergone bilateral mammary artery (BIMA) surgery (and additional vein grafts in 60.5% of the patients) since 1986. Both groups were comparable (P = not significant [NS]) for gender, age, most risk factors, objective ischaemia and left ventricular function; however, in the BIMA group there were more previous infarctions (P = 0.02), hypertension (P = 0.03), three-vessel disease (P = 0.0001), and less severe angina (P = 0.007). In the BIMA group, a mean of 3.1 (range 2-5) vessels were treated and in the MVP group 2.0 (range 2-3) vessels (P = 0.0001). Both groups were almost completely revascularized (NS). In 39.5% of the BIMA group, no veins were used and in 20.9% the BIMAs were used as sequential grafts. In-hospital mortality was comparable: 2.3% for BIMA and 1.4% for MVP, so were periprocedural infarctions (13.6% vs 8.3%), rethoracotomies (9.1% vs 0%), emergency procedures (0% vs 5.7%), low cardiac output (2.3% vs 5.6%) and other complications (18.2% vs 9.2%). The mean stay (days) on the ICU/CCU for BIMA was 2.3 and for MVP 1.6 (P = 0.005) and the mean hospital stay for BIMA 12.3 and for MVP 6.6 (P = 0.0001). The maximum and mean follow-up (months) of 43 BIMA and 71 MVP hospital survivors was 35 vs 72 and 9.5 vs 22.3 (P = 0.0001) with a late mortality of 0% and 4.2% (NS). MVP patients, including 12 with re-procedures, had more recurrent angina (17.7% vs 4.7%, P less than 0.05) and more often used anti-anginal medications (62.0% vs 18.6%, P less than 0.0001). Late complications (excluding re-procedures) were comparable for MVP and BIMA (20% vs 9.3%, 4.4% vs 0%, 9.2% vs 14%). MVP patients had more re-hospitalizations (34 vs 5, P less than 0.0001), re-catheterizations (33% vs 2.3%, P less than 0.0001) and cardiac re-procedures (16 vs 0, P = 0.0006) than BIMA patients. Recurrent-angina-free survival at 1 year was 96% after BIMA and 64% after MVP (P less than 0.01). Event-free survival at 1 year was 86% after BIMA and 58% after MVP (P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)