Introduction : Off-pump CABG has become the first therapeutic alternative in coronary surgery. This analysis tries to validate the expectations and build evidence on hospital mortality and -stay.
Methods : A consecutive series of 412 OPCAB patients is analysed and compared, using the Euroscore as risk-adjustment, with 1594 ECC CABG procedures performed in the same institution and interval (1997-2000). The Euroscore of the OPCAB patients was 4.5±3 % (range 0-14), the mean age 65±9 yrs and 18 were redo procedures. The Euroscore of the ECC patients was 5.0±3.5 % (range 0-22).
Results : The in-hospital mortality for the OPCAB patients was 2.9 % (P=0.35 versus Euroscore) and 4.2 % for the ECC patients. There was no OPCAB mortality up to 5 % risk (N=267 pts).
The cumulative stepwise risk- and sample-size adjusted comparison between observed and expected (Euroscore) mortality of the OPCAB patients identifies a P-value difference of .01 at the level of 5 % risk, decreasing to .08 at 10 % Euroscore risk.
A logistic regression identifies no difference (P=.84) between OPCAB and ECC, after Euroscore adjustment .
The risk-unadjusted postoperative hospital stay was 11±9 days (range 4-120, median 8). The OPCAB reduced the median stay by 1 day over most risk categories. The risk-unadjusted Mann-Whitney test identified a reduced hospital stay for OPCAB (P-value of <.0001).
After correction for Euroscore Risk, there was no more residual benefit for OPCAB in ANOVA analysis.
Conclusion : Extremely refined risk-adjusted techniques are required to identify a limited benefit for OPCAB in the presence of low hospital mortality and short hospital stay for ECC CABG. There is evidence that the benefits will increase in the presence of larger samples and higher risk.