Debunking the July Effect in Transcatheter Interventions in Structural Heart Disease: Truth or Myth?

Background: The "July effect", the perception of worse outcomes in the first month of training, has been previously demonstrated in critical care medicine and general surgery. However, the July effect in the context of structural heart interventions (i.e., transcatheter aortic valve replacement [TAVR] and MitraClip) remains unknown.

Methods: All adult patients undergoing TAVR or MitraClip in the 2012-2016 National Inpatient Sample were included. Outcomes were compared by procedure month and academic year quartiles (i.e., between the first academic year quartile [Q1] vs. the fourth quartile [Q4]). Outcomes between teaching and nonteaching hospitals were compared using risk-adjusted logistic difference-in-difference regression.

Results: During the study period, 94,170 TAVR (Q1: 25,250; Q4: 23,170) and 8750 MitraClip (Q1: 2220; Q4: 2150) procedures were performed. In-hospital mortality did not vary as per academic year quartiles for either procedure, even after risk adjustment. These findings persisted in sensitivity analysis by procedure month and newer device era (2015-2016; all p > 0.05). In the subgroup analysis, the unadjusted and adjusted Q1 vs. Q4 in-hospital mortality between teaching and nonteaching hospitals were similar for either procedure. In-hospital mortality also did not vary by procedure month when stratified by hospital teaching status for both procedures. However, postprocedural complication rates appeared to be improving among the TAVR teaching hospitals for stroke, major bleeding, and vascular complications (all p < 0.05).

Conclusions: In this large, nationwide study, the July effect was not evident for structural heart interventions. With increasing interest and growth in transcatheter procedures, early resident and fellow teaching can be achieved with appropriate supervision.