Page 21 - Journal of Structural Heart Disease Volume 5, Issue 2

Original Scientific Article 34
Figure 4. Subgroup Analysis for the Composite Safety Outcome of Any Adverse Event at 30 Days. Subgroup analysis for the com- posite safety outcome (defined as in Figure 3) at 30 days. Hazard ratios were generated using the Cox-proportional hazards model with the MAS group as the reference. Data markers indicate mean hazard ratios; lines represent 95% confidence interval. P values represent the likelihood of interaction between the subgroup variable and the composite safety outcome. Abbreviations as in Table 2. Valve size: small = 23 mm Sapien XT/Sapien 3 or 23/26 mm CoreValve Evolut; medium = 26 mm Sapien XT/Sapien 3 or 29 mm CoreValve Evolut; large = 29 mm Sapien XT/Sapien 3.
tem overheating, which is particularly advantageous during prolonged procedures.
The PAS cameras have power ratings ranging from 15 to 25 kW at 100 kVp, compared to the 100 kW at 100 kVp power rating of the FD20 [27-29]. Our anal- ysis suggests that the increased power rating of the FD20 does not confer a procedural advantage during TAVR, and may in fact contribute toward higher radi- ation doses. In addition, the contemporary PAS cam- eras utilize a digital flat panel display, which is also employed by the FD20. Compared with image inten- sifiers, flat panels have the advantage of minimizing image distortion [30]. However, the PAS flat panel de- tectors are smaller than that of the FD20, which may additionally explain why the PAS group experienced less radiation.
The PAS group had a significantly longer hospital length of stay compared to the MAS group. Univariate analysis demonstrated a significant association be- tween length of stay and alternative vascular access use (P = 0.004). Since the PAS group underwent sig- nificantly more alternative access, it is not unexpect- ed then that they experienced a longer hospital stay.
Another important finding of this study was the trend toward lower radiation exposure in the PAS group. This likely represents a fundamental differ- ence between PAS and MAS systems, whereby owing to their higher power rating and larger imaging field of view, MAS cameras accrue greater radiation doses, even when equivalent pulsed fluoroscopy settings are applied. This benefit of PAS over MAS appears to hold independently of fluoroscopy time, which was not significantly different between groups. Interest- ingly, the radiation doses observed in both the PAS and MAS group are lower than those reported in two prior studies investigating radiation exposure during TAVR [31, 32]. This discrepancy is largely attributed to lower fluoroscopy times used in our study, which reflect simplifications in TAVR procedure complexity over time.
While MAS remains the mainstay of intraoperative fluoroscopic imaging during TAVR procedures, PAS offers unique advantages. PAS cameras are versatile platforms which can complement existing MAS cam- eras, expanding the imaging armamentarium of insti- tutions participating in complex fluoroscopy-guided subspecialty procedures (Figure 5). Furthermore, PAS
Journal of Structural Heart Disease, April 2019
Volume 5, Issue 2:25-37