Mitral Regurgitation Grading in the Operating Room: A Systematic Review and Meta-analysis Comparing Preoperative and Intraoperative Assessments During Cardiac Surgery.

OBJECTIVE

To assess differences in mitral regurgitation (MR) grade between the preoperative and the intraoperative evaluations.

DESIGN

Systematic review and meta-analysis of 6 observational studies found from MEDLINE and EMBASE.

SETTING

Cardiac surgery.

PARTICIPANTS

One hundred thirty-seven patients.

INTERVENTION

Comparison between the preoperative MR assessment and the intraoperative evaluation conducted under general anesthesia (GA), with or without "hemodynamic matching" (HM) (artificial increase of afterload).

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the difference between the preoperative and intraoperative MR grade under "GA-only" or "after-HM." Secondary analyses addressed differences according to effective regurgitant orifice area (EROA), regurgitant volume (RVol), color-jet area, and vena contracta width. Risk of MR underestimation was found under "GA-only" (SMD: 0.55; 95% confidence interval [CI], 0.31-0.79, p < 0.00001), but not "after-HM" (SMD: -0.16; 95% CI, -0.46 to 0.13, p = 0.27). Under "GA-only", EROA had a trend toward underestimation (p = 0.07), RVol was reliable (p = 0.17), while reliance on color-jet area and vena contracta width incur risk of underestimation (both p = 0.003). After HM, EROA accurately reflected preoperative MR (p = 0.68) while RVol had a trend toward overestimation (p = 0.05). The overall reported incidence of misdiagnoses was slightly more common under "GA-only" (mean 48%, 39% underestimation, 9% overestimation; range: 32%-57%) than "after-HM" (mean 41%, 12% underestimation, 29% overestimation; range: 33%-50%). Only the minority of misdiagnoses were clinically relevant: underestimation was around 10% (both approaches), but 18% had clinically significant overestimation "after-HM" as compared with 3% under GA-only.

CONCLUSIONS

Intraoperative assessment under "GA-only" significantly underestimated MR. A more accurate intraoperative evaluation can be obtained with afterload manipulation, although HM strategy carries high risk of clinically significant overestimation.