Comparison of outcomes of pulmonary valve replacement in adult versus paediatric hospitals: institutional influence†

Managing confounding and effect modification in pediatric/congenital interventional cardiology research

Measuring the effect of a treatment on outcomes is an important goal for research in pediatric/congenital interventional cardiology. The breadth of anatomic and physiologic variations, patient ages, and genetic syndromes and noncardiac comorbid conditions all represent sources of potential confounding and effect modification that are major obstacles to this goal. If not accounted for, these factors can obscure the "true" treatment effect and lead to spurious conclusions about the relative efficacy and/or safety of therapies. In this review, we discuss the importance of confounding and effect modification in pediatric/congenital interventional cardiology research. We define these terms and discuss strategies (both in study design and data analysis) to mitigate error introduced by confounding and effect modification. The importance of confounding by indication in pediatric/congenital cardiology is discussed along with specific methods to address it.

Outcomes of Operator-Directed Sedation and Anesthesiologist Care in the Pediatric/Congenital Catheterization Laboratory: A Study Utilizing Data From the IMPACT Registry

OBJECTIVES

The objective of this study was to assess contemporary use of operator directed sedation (ODS) and anesthesiologist care (AC) in the pediatric/congenital cardiac catheterization laboratory (PCCL), specifically evaluating whether the use of operator-directed sedation was associated with increased risk of major adverse events.

BACKGROUND

The safety of ODS relative to AC during PCCL procedures has been questioned.

METHODS

A multicenter, retrospective cohort study was performed studying procedures habitually performed with ODS or AC at IMPACT (Improving Adult and Congenital Treatment) registry hospitals using ODS for ≥5% of cases. The risks for major adverse events (MAE) for ODS and AC cases were compared, adjusted for case mix. Current recommendations were evaluated by comparing the ratio of observed to expected MAE for cases in which ODS was inappropriate (inconsistent with those guidelines) with those for similar risk AC cases, as well as those in which ODS or AC was appropriate.

RESULTS

Of the hospitals submitting data to IMPACT, 28 of 101 met inclusion criteria. Of the 7,042 cases performed using ODS at these centers, 88% would be inappropriate. Use of ODS was associated with lower likelihood of MAE both in observed results (p < 0.0001) and after adjusting for case-mix (odds ratio: 0.81; p = 0.006). Use of AC was also associated with longer adjusted fluoroscopy and procedure times (p < 0.0001 for both). The observed/expected ratio for ODS cases with high pre-procedural risk (inappropriate for ODS) was significantly lower than that for AC cases with comparable pre-procedural risk. Across a range of pre-procedural risks, there was no stratum in which risk for MAE was lower for AC than ODS.

CONCLUSIONS

Across a range of hospitals, ODS was used safely and with improved efficiency. Clinical judgment better identified cases in which ODS could be used than pre-procedural risk score. This should inform future guidelines for the use of ODS and AC in the catheterization laboratory.

In vitro Assessment of the Impacts of Leaflet Design on the Hemodynamic Characteristics of ePTFE Pulmonary Prosthetic Valves

Prosthetic pulmonary valves are widely used in the management procedures of various congenital heart diseases, including the surgical pulmonary valve replacement (PVR) and right ventricular outflow tract reconstruction (RVOT). The discouraging long-term outcomes of standard prostheses, including homografts and bioprosthetic, constrained their indications. Recent developments in the expanded-polytetrafluoroethylene (ePTFE) pulmonary prosthetic valves provide promising alternatives. In this study, the hemodynamic characteristics of bileaflet and trileaflet ePTFE valve designs were experimentally evaluated. The in vitro tests were performed under the right ventricle (RV) flow conditions by using an in vitro RV circulatory system and particle image velocimetry (PIV). The leaflet kinetics, trans-valvular pressure gradients, effective orifice areas, regurgitant fractions, energy losses, velocity fields, and Reynolds shear stress (RSS) in both prostheses were evaluated. The opening of the bileaflet and trileaflet valve takes 0.060 and 0.088 s, respectively. The closing of the former takes 0.140 s, in contrast to 0.176 s of the latter. The trans-valvular pressure is 6.8 mmHg in the bileaflet valve vs. 7.9 mmHg in the trileaflet valve. The effective orifice area is 1.83 cm2 in the bileaflet valve and 1.72 cm2 in the trileaflet valve. The regurgitant fraction and energy loss of bileaflet are 7.13% and 82 mJ, which are 7.84% and 101.64 mJ in its bileaflet counterpart. The maximum RSS of 48.0 and 49.2 Pa occur at the systole peak in the bileaflet and trileaflet valve, respectively. A higher average RSS level is found in the bileaflet valve. The results from this preliminary study indicate that the current bileaflet prosthetic valve design is capable of providing a better overall hemodynamic performance than the trileaflet design.