Table:
Checklist for quality assessment and scoring of nonrandomized studies
Selection	1. Assignment for treatment-Any criteria reported (if yes, 1 star)?
2. How representative was the reference group (CPB) in comparison to the general population for CABG? (If yes, 1 star, no star if the patients were selected or selection of group was not described.)
3. How representative was the treatment group (OPCAB) in comparison to the general population for CABG? (If drawn from the same community as the reference group, 1 star, no star if drawn from a different source or selection of group was not described.)
Comparability	4. Group comparable for 1, 2, 3, 4, 5. (If yes, 1 star was assigned for each of these characteristics. No star was assigned if the two groups differed.)
5. Group comparable for 6, 7, 8, 9, 10. (If yes, 1 star was assigned for each of these characteristics. No star was assigned if the two groups differed.)
Outcome assessment	6. Clearly defined outcome of interest. (If yes, 1 star for information ascertained by record linkage or interview, no star if this information was not reported.)
7. Follow-up (1 star if described.)
Comparability variables: (1) Age; (2) Gender; (3) Hypertension; (4) Diabetes; (5) Ejection fraction; (6) 3-Vessel Disease; (7) Left Main Stem Disease; (8) Urgent or Emergent Operation; (9) Viability Studies; (10) Surgeon or Hospital Volume

Continue parse the picture with markdown style: | <COLSPAN=2> Checklist for quality assessment and scoring of nonrandomized studies | 
 | --- | --- | 
 | <ROWSPAN=3> Selection | 1. Assignment for treatment-Any criteria reported (if yes, 1 star)? | 
 | 2. How representative was the reference group (CPB) in comparison to the general population for CABG? (If yes, 1 star, no star if the patients were selected or selection of group was not described.) | 
 | 3. How representative was the treatment group (OPCAB) in comparison to the general population for CABG? (If drawn from the same community as the reference group, 1 star, no star if drawn from a different source or selection of group was not described.) | 
 | <ROWSPAN=2> Comparability | 4. Group comparable for 1, 2, 3, 4, 5. (If

yes, 1 star was assigned for each of these characteristics. No star was assigned if the two groups differed.) | 
 | 5. Group comparable for 6, 7, 8, 9, 10. (If yes, 1 star was assigned for each of these characteristics. No star was assigned if the two groups differed.) | 
 | <ROWSPAN=2> Outcome assessment | 6. Clearly defined outcome of interest. (If yes, 1 star for information ascertained by record linkage or interview, no star if this information was not reported.) | 
 | 7. Follow-up (1 star if described.) | 
 |  | Comparability variables: (1) Age; (2) Gender; (3) Hypertension; (4) Diabetes; (5) Ejection fraction; (6) 3-Vessel Disease; (7) Left Main Stem Disease; (8) Urgent or Emergent Operation; (9) Viability Studies; (10) Surgeon or Hospital Volume |