MitraClip therapy in surgical high-risk patients: identification of echocardiographic variables affecting acute procedural outcome.

OBJECTIVES: The aim of the study was to assess predictors of acute procedural failure in surgical high-risk patients undergoing MitraClip (Abbott Vascular, Abbott Park, Illinois) therapy.

BACKGROUND: MitraClip implantation is a novel percutaneous option to treat significant mitral regurgitation (MR).

METHODS: In 300 patients (75 ± 9 years of age, 190 [63%] men), of whom 32 (10.7%) had been unsuccessfully treated (discharge MR grade of >2+), baseline clinical and echocardiographic variables were evaluated by exact logistic regression and classification tree analyses to assess their impact on acute procedural failure. Acute procedural failure was differentiated into aborted procedure (no MitraClip implanted; n = 11) and "clip failure" (inadequate MR reduction despite MitraClip implantation; n = 21).

RESULTS: Multivariate logistic regression identified effective regurgitant orifice area (EROA), mitral valve orifice area (MVOA), and mean transmitral pressure gradient (TMPG) as independent predictors of overall acute procedural failure. Classification tree analysis revealed that an EROA >70.8 mm(2) (n = 28) was associated with a high rate (25%) of clip failures, whereas the combination of an MVOA ≤3.0 cm(2) and a TMPG ≥4 mm Hg (n = 16) was associated with a high rate (37.5%) of aborted procedures. Failure rates of ≤10% were observed in all patients with an EROA ≤70.8 mm(2) and either an MVOA >3.0 cm(2) (n = 217) or an MVOA ≤3.0 cm(2) in concert with a TMPG ≤3 mm Hg (n = 39). Multinomial logistic regression identified an EROA >70.8 mm(2) and a TMPG ≥4 mm Hg as independently predictive of clip failure, but an MVOA ≤3.0 cm(2) and a TMPG ≥4 mm Hg as independently predictive of procedure abortion.

CONCLUSIONS: In surgical high-risk patients undergoing MitraClip therapy, a TMPG ≥4 mm Hg, an EROA ≥70.8 mm(2), and an MVOA ≤3.0 cm(2) carry an increased risk of procedural failure.