A Systematic Review and Meta-Analysis of Prevalence, Characteristics, and Impact of Mitral Annular Calcification on Outcomes After Transcatheter Aortic Valve Implantation

Abstract

There is a paucity of data on the prognostic impact of mitral annular calcification (MAC) in patients who underwent transcatheter aortic valve implantation (TAVI) with conflicting results being reported by the studies that are published. Therefore, we performed a meta-analysis to assess the short-term and long-term outcomes of MAC in patients after TAVI. Of 25,407 studies identified after the initial database search, 4 observational studies comprising 2,620 patients (2,030 patients in the nonsevere MAC arm and 590 patients in the severe MAC arm) were included in the final analysis. Compared with patients with nonsevere MAC, the severe MAC group was associated with significantly higher incidences of overall bleeding (0.75 [0.57 to 0.98], p = 0.03, I² = 0%) at 30 days. However, no significant difference was observed between the 2 groups for the rest of the 30-day outcomes: all-cause mortality (0.79 [0.42 to 1.48], p = 0.46, I² = 9%), myocardial infarction (1.62 [0.37 to 7.04], p = 0.52, I² = 0%), cerebrovascular accident or stroke (1.22 [0.53 to 2.83], p = 0.64, I² = 0%), acute kidney injury (1.48 [0.64 to 3.42], p = 0.35, I² = 0%), and pacemaker implantation (0.70 [0.39 to 1.25], p = 0.23, I² = 68%). Similarly, follow-up outcomes also showed no significant difference between the 2 groups: all-cause mortality (0.69 [0.46 to 1.03], p = 0.07, I² = 44%), cardiovascular mortality (0.52 [0.24 to 1.13], p = 0.10, I² = 70%) and stroke (0.83 [0.41 to 1.69], p = 0.61, I² = 22%). The sensitivity analysis, however, demonstrated significant results for all-cause mortality (0.57 [0.39 to 0.84], p = 0.005, I² = 7%) by removing the study by Okuno et al⁵ and cardiovascular mortality (0.41 [0.21 to 0.82], p = 0.01, I² = 66%) by removing the study by Lak et al.⁷ In conclusion, our meta-analysis corroborates the notion that isolated MAC is not an independent predictor of long-term mortality after TAVI and determines severe MAC to be a predictor of mortality at follow-up because of the higher incidence of mitral valve dysfunction associated with it.