Outcomes After Conversion in the Veterans Affairs Randomized On Versus Off Bypass Trial

doi:10.1016/j.athoracsur.2011.05.122

The Annals of Thoracic Surgery

Volume 92, Issue 6, December 2011, Pages 2147-2154

https://doi.org/10.1016/j.athoracsur.2011.05.122 Get rights and content

Background

The Randomized On versus Off Bypass trial reported conversion of 12.4% (n = 137) off-pump coronary artery bypass (OPCAB) patients and 3.6% (n = 40) on-pump cardiopulmonary bypass (CPB) patients. This paper explored outcomes after conversions.

Methods

Elective and urgent CABG patients (n = 2,203) at 18 sites were studied. Randomization within 54 participating surgeons occurred preoperatively, after which conversion occurred if clinically indicated. Conversion reasons and outcomes were captured prospectively with additional details retrospectively extracted from patient records by a core clinical group.

Results

Conversion rates varied considerably across participating surgeons. Converted OPCAB patients had more right coronary disease and coronary targets less than 1.5 mm. Conversions were elective in 49.3% of cases, urgent in 27.2%, or emergent in 23.5%. Elective conversions were mainly for poor exposure-intramyocardial vessel (35.8%). Urgent and emergent conversions were usually for hemodynamic instability (89.2% and 75.0%, respectively). Compared with CPB and OPCAB patients, OPCAB-converted patients had more 30-day complications and deaths (composite outcome rate of 5.7% and 5.5% vs 17.5% respectively, p < 0.001). Thirty-day outcomes for OPCAB-converted patients trended worse for emergent versus elective conversions (31.3% vs 13.4%, respectively, p = 0.05). One-year composite outcome rate (death, nonfatal myocardial infarction or revascularization) in OPCAB-converted patients was worse than in CPB patients (13.5% vs 7.1%, p = 0.02), but similar to OPCAB-nonconverted (9.4%).

Conclusions

The OPCAB patients requiring conversion had worse 30-day and 1-year outcomes. The OPCAB patients with right coronary artery disease or small targets were more often converted. The 30-day composite outcome trended worst for emergent OPCAB conversions.

Section snippets

Material and Methods

The ROOBY trial was a controlled, single-blind, randomized trial initiated in April 2002 [5, 7]. Essential components of the surgical protocol included Swan-Ganz catheter monitoring, standard median sternotomy, heparinization to an activated clotting time of greater than 400 seconds for all patients, standard use of cardiopulmonary bypass pump for on-pump procedures, and use of OPCAB stabilization devices of choice with cardiopulmonary bypass on standby. For safety, conversion was allowed at

Results

The ROOBY trial randomized 2,203 patients to on-pump (n = 1,099) or off-pump (n = 1,104) procedures. Forty (3.6%) on-pump patients were converted and 137 (12.4%) off-pump patients were converted. Conversion rates varied widely (0% to 55.6%) across surgeons. Baseline characteristics (Table 1) were similar across the CPB, OPCAB, and OPCAB-c groups, except that the OPCAB-c group more frequently had right coronary artery disease. In contrast to the other groups, the CPB-c group was significantly

Comment

This substudy supports the main ROOBY study findings that 1-year outcomes and graft patency were worse with off-pump CABG than on-pump CABG. Even after converted patients were excluded, the overall composite adverse outcome rate from time of surgery to 1 year remained significantly lower in the CPB arm than the OPCAB arm (9.7% vs 13.7%, p < 0.01). Graft patency was also better in the CPB group. Conversions added to the adverse impact, as 30-day and 1-year composite outcome rates were highest in

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Cited by (39)

Impact of Surgeon Experience and Centre Volume on Outcome After Off-Pump Coronary Artery Bypass Surgery: Results From the European Multicenter Study on Coronary Artery Bypass Grafting (E-CABG) Registry
2023, Heart Lung and Circulation
The aim of this study was to assess the impact of surgeon experience and centre volume on early operative outcomes in patients undergoing off-pump coronary artery bypass (OPCAB) surgery.
Of 7,352 patients in the European Multicenter Study on Coronary Artery Bypass Grafting (E-CABG) registry, 1,549 underwent OPCAB and were included in the present analysis. Using adjusted regression analysis, we compared major early adverse events after procedures performed by experienced OPCAB surgeons (i.e., ≥20 cases per year; n=1,201) to those performed by non-OPCAB surgeons (n=348). Furthermore, the same end points were compared between procedures performed by OPCAB surgeons in high OPCAB volume centres (off-pump technique used in >50% of cases; n=894) and low OPCAB volume centres (n=307).
In the experienced OPCAB surgeon group, we observed shorter procedure times (β –43.858, 95% confidence interval [CI] –53.322 to –34.393; p<0.001), a lower rate of conversion to cardiopulmonary bypass (odds ratio [OR] 0.284, 95% CI 0.147–0.551; p<0.001), a lower rate of prolonged inotrope or vasoconstrictor use (OR 0.492, 95% CI 0.371–0.653; p<0.001), a lower rate of early postprocedural percutaneous coronary interventions (OR 0.335, 95% CI 0.169–0.663; p=0.002), and lower 30-day mortality (OR 0.423, 95% CI 0.194–0.924; p=0.031). In high OPCAB volume centres, we found a lower rate of prolonged inotrope use (OR 0.584, 95% CI 0.419–0.814; p=0.002), a lower rate of postprocedural acute kidney injury (OR 0.382, 95% CI 0.198–0.738; p=0.004), shorter duration of intensive care unit (β –1.752, 95% CI –2.240 to –1.264; p<0.001) and hospital (β –1.967; 95% CI –2.717 to –1.216; p<0.001) stays, and lower 30-day mortality (OR 0.316, 95% CI 0.114–0.881; p=0.028).
Surgeon experience and centre volume may play an important role on the early outcomes after OPCAB surgery.
Reply
2019, Annals of Thoracic Surgery
Reply
2019, Annals of Thoracic Surgery
Off-Pump Versus On-Pump Impact: Diabetic Patient 5-Year Coronary Artery Bypass Clinical Outcomes
2019, Annals of Thoracic Surgery
Citation Excerpt :
Landmark analyses for the post-CABG outcomes that occurred from 1 to 5 years were completed for the primary and secondary end points. Because prior ROOBY publications identified a reduced 1-year survival rate for converted operations (both off- to on-pump and on- to off-pump conversions), a sensitivity analysis was performed after removing all converted patients to ensure that this study’s findings were robust [10]. Because these ROOBY-FS diabetic patients’ baseline patient characteristics were documented as being balanced between treatments [7], bivariate statistical comparisons were performed by using χ2 tests and Fisher exact tests (for categorical end points) or by using t tests and Wilcoxon rank sum analyses (for continuous variables).
For diabetic patients who require coronary artery bypass graft (CABG) operation, controversy persists whether an off-pump or an on-pump approach may be advantageous. This US-based, multicenter, randomized, controlled trial, Department of Veterans Affairs Randomization On versus Off Bypass Follow-up Study, compared diabetic patients’ 5-year clinical outcomes for off-pump versus on-pump procedures.
From 2002 to 2008, 835 medically treated (ie, oral hypoglycemic agent or insulin) diabetic patients underwent either off-pump (n = 402) or on-pump (n = 433) CABG. Five-year primary end points included all-cause death and major adverse cardiovascular events (MACE; composite included all-cause death, myocardial infarction, or repeat revascularization). Secondary 5-year end points included cardiac death and MACE-related components. With baseline risk factors balanced, outcomes were evaluated by using a p value less than or equal to 0.01; nonsignificant trends were reported for p values greater than 0.01 and less than or equal to 0.15.
Five-year all-cause death rates were 20.2% off pump versus 14.1% on pump (p = 0.0198). No differences were seen in MACE (32.6% off-pump approach versus 28.6% on-pump approach, p = 0.216), repeat revascularization (12.4% off-pump approach versus 11.8% on-pump approach, p = 0.770), and nonfatal myocardial infarction (12.7% off-pump approach versus 10.4% on-pump approach, p = 0.299). Cardiac death trended worse with off-pump CABG (9.0%) than with on-pump CABG (6.25%, p = 0.137). Sensitivity analyses that removed conversions confirmed these findings.
With a 6.1% absolute difference, a strong trend toward improved 5-year survival was observed with on-pump CABG for medically treated diabetic patients. No off-pump advantage was found for any 5-year end points. A future clinical trial now appears warranted to rigorously compare off-pump versus on-pump longer term outcomes for diabetic patients.
Costs Five Years After Off-Pump or On-Pump Coronary Artery Bypass Surgery
2019, Annals of Thoracic Surgery
Coronary artery bypass grafting (CABG) is a common surgical treatment for ischemic heart disease. Little is known about the long-term costs of conducting the surgery on-pump or off-pump.
As part of the Randomized On/Off Bypass follow-up study, we followed 2,203 participants randomized to on-pump (n = 1,099) and off-pump (n = 1,104) CABG for 5 years using Department of Veterans Affairs and Medicare administrative data. We examined annual costs through 5 years, standardized to 2016 dollars, using multivariate regression models, controlling for site and baseline patient factors.
In the first year, including the CABG surgery, annual average costs were $66,599 (SE, $1,946) for the on-pump group and $70,552 (SE, $1,954) for the off-pump group. In years 2 to 5, average costs ranged from $15,000 to $20,000 per year. There was no significant difference between on-pump and off-pump across the 5 years. We explored differences among high-risk subgroups (diabetes, chronic obstructive pulmonary disease, peripheral vascular disease, cerebrovascular disease, renal dysfunction, ejection fraction < 35%, over age 70 years), and found no treatment assignment by time interactions, except for a nonsignificant trend in patients with diabetes.
At 5 years, the average costs of off-pump and on-pump CABG patients did not statistically differ. Costs do not favor one approach and the decision should be based on clinical risks, especially in subgroups. Future research is warranted to examine post-CABG costs and outcomes for diabetic patients over time.
Off-Pump Coronary Artery Bypass Grafting
2018, Atlas of Cardiac Surgical Techniques

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Original articleAdult cardiacOutcomes After Conversion in the Veterans Affairs Randomized On Versus Off Bypass Trial

Background

Methods

Results

Conclusions

Section snippets

Material and Methods

Results

Comment

Off-pump versus conventional coronary artery bypass grafting: a meta-analysis and consensus statement from the 2004 ISMICS Consensus Conference

Innovations: Technology & Techniques in Cardiothoracic & Vascular Surgery

Aborted off-pump coronary artery bypass patients have much worse outcomes than on-pump or successful off-pump patients

Circulation

Conversion to on pump from OPCAB is associated with increased mortality: results from a randomized controlled trial

Eur J Cardiothorac Surg

Conversion in off-pump coronary artery bypass grafting: an analysis of predictors and outcomes

Ann Thorac Surg

On-pump versus off-pump coronary-artery bypass surgery

N Engl J Med

Original article
Adult cardiac
Outcomes After Conversion in the Veterans Affairs Randomized On Versus Off Bypass Trial