Five-Year Outcomes after Off-Pump or On-Pump Coronary-Artery Bypass Grafting

Expertise-based design in surgical trials: a narrative review

Randomized controlled trials (RCTs) are the most robust study design for evaluating the safety and efficacy of a therapeutic intervention. However, their internal validity are at risk when evaluating surgical interventions. This review summarizes existing expertise- based trials in surgery and related methodological concepts to guide surgeons performing this work. We provide caseloads required to reach the learning curve for various surgical interventions and report criteria for expertise from published and unpublished expertise-based trials. In addition, we review design and implementation concepts of expertise-based trials, including recruitment of surgeons, crossover, ethics, generalizability, sample size and definitions for learning curve. Several RCTs have used an expertise-based design. We found that the majority of definitions used for expertise were vague, heterogeneous, and inconsistent across trials evaluating the same surgical intervention. Statistical methods exist to adjust for the learning curve; however, there is limited guidance. We developed the following criteria for surgical expertise for future trials: 1) decide on the proxy to be used for the learning curve, and 2) assess eligible surgeons by comparing their performance to the previously defined expertise criteria.

Oxidative Stress in Patients before and after On-Pump and Off-Pump Coronary Artery Bypass Grafting: Relationship with Syntax Score

Objective

Coronary artery bypass grafting (CABG) represents the significant source of increased oxidative stress (OS). We aimed to follow the OS status parameters (i.e., ischemia-modified albumin (IMA), malondialdehyde (MDA), superoxide anion, prooxidant-antioxidant balance (PAB), total oxidant status (TOS), total antioxidant status (TAS), and superoxide-dismutase (SOD)) change through the predefined study times in two different surgical procedures, i.e., cardiopulmonary bypass (CPB) and off-pump coronary artery bypass grafting (OPCAB). Additionally, we aimed to investigate those OS status parameters in specific study times according to SYNTAX score (SS), an established angiographic score for evaluating the extensity and severity of coronary artery disease. Patients and Methods. A total of 107 patients that were planned to undergo CABG were included (i.e., 47 patients in OPCAB and 60 patients in CPB group). Blood samples were taken at 6 time intervals: before surgery (t1), immediately after intervention (t2), 6 h (t3), 24 h (t4), 48 h (t5), and 96 h after termination of the operation (t6).

Results

IMA levels were higher in CPB than that in OPCAB baseline and rose in CPB group in t2 point. TOS decreased in both study groups, compared to baseline values, but without statistical significance. Superoxide anion and PAB significantly increased in t3-t6 study times, in both groups. MDA significantly increased only in CPB group in t5 and t6 interval. MDA was significantly higher in CPB group compared to OPCAB in t6 study point. CPB patients had significantly lower TAS compared to OPCAB patients at the beginning and in t2 and t3 study points. They also had significantly lower SOD activities compared to OPCAB, baseline, and in several study points. Moreover, TAS, SOD, and TAS/TOS ratio were significantly lower, whereas PAB and TOS/TAS were significantly higher in patients with high SS compared to corresponding groups. SOD activity, IMA, and TAS level were the best predictors of high SS.

Conclusion

CPB patients were in more severe ischemia baseline than OPCAB group and IMA rose in CPB patients immediately after the surgery end, but not later. Also, the antioxidant status was significantly lower, whereas the prooxidant status was significantly higher in patients with high SS compared to corresponding groups. SOD activity, IMA, and TAS level were the best predictors of CAD (as determined with SS), showing that SOD and IMA had very good discriminatory capability towards higher SS status.

On-Pump vs Off-Pump coronary artery bypass surgery in atrial fibrillation. Analysis from the polish national registry of cardiac surgery procedures (KROK)

Background

No single randomized study has ever before addressed the safety of On-Pump coronary artery bypass grafting (CABG) vs Off-Pump CABG in the setting of atrial fibrillation (AF) and data from small observational samples remain inconclusive.

Methods and findings

Procedural data from KROK (Polish National Registry of Cardiac Surgery Procedures) were retrospectively collected. Of initial 188,972 patients undergoing CABG, 7,913 presented with baseline AF (76.0% men, mean age 69.1±8.2) and underwent CABG without concomitant valve surgery between 2006–2019 in 37 reference centers across Poland. Mean follow-up was 4.7±3.5 years (median 4.3 IQR 1.7–7.4). Cox proportional hazards models were used for computations. Of included patients, 3,681 underwent On-Pump- (46.52%) as compared to 4,232 (53.48%) who underwent Off-Pump CABG. Patients in the latter group less frequently were candidates for complete revascularization (P<0.001). In an unadjusted comparison, On-Pump surgery was associated with significantly worse survival at 30 days: HR: 1.28; 95%CIs: (1.07–1.53); P = 0.007. Along the 13-year study period, the trend shifted in favor of On-Pump CABG: HR: 0.92; 95%CIs: (0.83–0.99); P = 0.005. After rigorous propensity matching, 636 pairs were identified. The direction and magnitude of treatment effects was sustained with HRs of 3.58; (95%CIs: 1.34–9.61); p = 0.001 and 0.74; [95%CIs: 0.56–0.98]; p = 0.036) for 30-day and late mortality respectively.

Conclusions

Off-Pump CABG offered 30-day survival benefit to patients undergoing CABG surgery and presenting with underlying AF. On-Pump CABG was associated with significantly improved survival at long term.

Long-term outcomes of multiple and single arterial off-pump coronary artery bypass grafting

BACKGROUND

To compare the clinical outcomes between multiple arterial (MA) and single arterial (SA) off-pump coronary artery bypass grafting (OPCAB) when applied to left main coronary disease or three-vessel disease.

METHODS

A total of 537 patients with left main coronary disease or three-vessel disease underwent MA OPCAB (n=114) or SA OPCAB (n=423) in our center from January 2006 to December 2008. The propensity score matching (PSM) was used to obtain the risk-adjusted outcome. Both the perioperative and long-term results were analyzed.

RESULTS

The median follow-up time was 117 months (interquartile range, 110 to 128 months). There was no statistical difference in postoperative mortality and the volume of drainage. The intensive care unit (ICU) length of stay (LOS) of the MA group was shorter than that of the SA group {1 [1-2] vs. 2 [1-3], P=0.001). In the long term, the mortality (5.7% vs. 17.5%, P=0.006), cardiac mortality (1.0% vs. 8.8%, P=0.008), fatal myocardial infarction (MI) rate (0.0% vs. 6.1%, P=0.015) and incidence of readmission for heart failure (19.8% vs. 37.7%, P=0.003) were lower in the MA group than in the SA group. The distributions of NYHA class (P<0.001) and CCS class (P<0.001) were better in the MA group than in the SA group. There was no significant difference in other outcomes. These results were consistent with the K-M curves of freedom from the adverse events.

CONCLUSIONS

MA OPCAB was as safe as SA OPCAB, providing better perioperative recovery and better long-term clinical outcomes in the treatment of left main coronary disease or three-vessel disease.