Impact of Prosthesis Oversizing on Clinical Outcomes of Trans Catheter Aortic Valve Implantation Using Self Expandable Evolute R Valve

Abstract Background Transcatheter Aortic Valve Implantation (TAVI) has a growing target population after being indicated even in low-surgical-risk patients with severe symptomatic aortic stenosis. However, postoperative short- and long-term outcomes can be compromised due to para-valvular leakage (PVL). A lot of manoeuvres have been investigated to decrease this partially avoidable operational hazard. Oversizing is a main technique to decrease the PVL, despite being itself a risky procedural step. Many studies have been conducted to identify the optimum degree of oversizing. However, studies about oversizing by more than 20% are less frequent. Objectives In this study, we are trying to prove the safety and efficacy of oversizing equal to or more than 20%. Avoiding new-onset conduction disturbance, coronary encroachment, annular injury, and decreasing the PVL were our primary end points. Our secondary end point was to find predictors for new-onset conduction disturbance and para-valvular leakage in a specific low-risk population. Methods We initially included 209 patients who underwent TAVI using self-expandable valves. 66 patients were excluded because of the baseline conduction disturbance and lack of sufficient data, so 143 patients, 60 (42.0%) females and 83 (58.0%) males, were enrolled in our study as two groups: Group A included 97 patients with an oversizing index (OI) of less than 20%, and group B included 46 patients with an OI of 20% or more. We conducted a new technique for more accurate measuring of the OI in the context of the implantation depth, and our patients were categorized using this technique. The study was done retrospectively for 49 patients and prospectively for the rest of the patients. Results Our findings have met our primary end point in terms of the safety and efficacy of extreme oversizing. There was no significant difference between both groups in terms of new-onset conduction disturbance (NOCD), with zero cases of annular rupture or coronary encroachment. In terms of efficacy There was zero percent of significant PVL (grade 2 or more) in the extreme oversizing group versus 14.4% of significant PVL in the other group (P value 0.007). The ROC curve found that the minimum depth of implantation-derived oversizing (DIDO) to predict no significant PVL was 17%. Conclusion In a matched cohort, the depth of implantation can affect the degree of oversizing, especially in the larger valve sizes, as the deeper we implant the valve, the less than expected the degree of oversizing is in traditional methods of calculation. In the absence of severe LVOT calcification, the optimum index of the depth of implantation-derived oversizing (DIDO) is at least 17% to prevent significant PVL.