Page 18 - Journal of Structural Heart Disease Volume 4, Issue 2

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Original Scienti c Article
which was signi cantly higher than that for electively treated patients (7.7%, P < 0.0001). Estimated 1-year survival was 59.3% in emergency and 82.7% in elec- tively treated patients (P = 0.0009) [11].
Valve Type
Our data suggest that a self-expanding prosthesis may have advantages. First, current iterations are 14- F, which may be advantageous if no iliofemoral im- aging has been performed. Second, minimizing rapid pacing make be useful if there are concerns about hemodynamic stability. Third, the risk of annular rupture from over-sizing is rare with self-expanding versus balloon-expandable valves, which are more dependent on accurate annular sizing as well as the degree and extent of calci cation. Finally, if treating a failed surgical bioprosthesis, there is the advantage of supra-annular valve function and lower post-pro- cedural gradients with self-expanding valves. The lat- est iteration also o ers the advantage of being repo- sitionable.
Limited Pre- and Peri-Procedural Imaging
One major concern with primary TAVI is the limited use of pre- and peri-procedural imaging, which plays a pivotal role in planning. MSCT is now considered the gold standard for pre-procedural TAVI assess- ment, and expert consensus guidelines exist on CT imaging prior to TAVI [4]. MSCT has several advan- tages over TTE and uoroscopy-based staging tech- niques. These include a “single test assessment” of the vascular access site and the aortic valve complex and more accurate annular sizing and assessment of the aorta, which may impact the degree of post-pro- cedural aortic regurgitation and the ability to predict appropriate uoroscopic implant projections.
Echocardiography, by contrast, tends only to iden- tify the antero-posterior diameter of the aortic annu- lus, which is smaller on average than the lateral-to-lat- eral aortic annular diameter. With a self-expanding prosthesis (as used in most patients in this study), al- lowance can be made for potential discrepancies and appropriate up-sizing when measurements are bor- derline. Irrespective, a retrospective study by Mylotte et al. found that CT-based annular analysis revealed incorrect CoreValve size selection by TTE in up to 50% of patients [19].
Paravalvular Aortic Regurgitation
There is now clear data to suggest that the pre- cision of the annular measurement may impact the degree of PAR seen post-implant [20]. PAR ≥ 2+ (mod- erate to severe) is an independent predictor of short- and long-term mortality [21]. Therefore, minimizing PAR post-TAVI is important. In this series using a min- imalist approach, 12.5% of patients exhibited PAR > 2+. This rate would need to be reduced if primary TAVI is to become a useful tool. Repositionable valves should prove valuable in this respect.
GA or Sedation
From a procedural aspect, limited use of TEE allows for conscious sedation rather than GA, which is asso- ciated with shorter implant time, decreased stay in the intensive care unit, and faster discharge from the hospital [22, 23].
Durand et al. undertook TAVI using the Edwards Sa- pien XT prosthesis in 151 consecutive patients using local anesthesia and uoroscopy only. Conversion to GA was required in 3.3% of patients and was related to complications. Device success was similar to that in our series (95.4% vs. 96.1%), with similar 30-day mor- tality (6.6% vs. 9.3%) [24].
Cost-E ectiveness
TAVI is a cost-e ective treatment. Cost per life-year gained is well within accepted values for common- ly used cardiovascular technologies irrespective of geography and de nition [25]. Primary TAVI should further impact cost-e ectiveness as it limits the pa- tient to one de nitive treatment episode. Attizani et al. reported the use of a minimally invasive strategy in an elective population, de ned as local anesthe- sia with or without conscious sedation, performed in the catheter lab without TEE guidance. They found this strategy to be cost-e ective, with a cost saving of $16,000 per case compared with standard care [26].
Conclusion
A minimalist approach to TAVI does not o er con- temporary levels of procedural success, but a 95% success rate may be considered acceptable in emer- gency or urgent settings. A self-expanding prosthesis may be particularly suited to this clinical scenario.
Cockburn J. et al.
Towards Primary TAVI