Impact of Patient Prosthesis Mismatch on the Outcome of Transcatheter Pulmonic Valve Implantation.
Takajo D, Forbes TJ, Kobayashi D.Am J Cardiol. 2021 May 27:S0002-9149(21)00376-3. doi: 10.1016/j.amjcard.2021.04.022. Online ahead of print.PMID: 34053630
Take Home Points:
- Patient prosthesis mismatch (PPM) is an important factor of the outcome in transcatheter aortic valve implantation. However, the impact of PPM in transcatheter pulmonic valve implantation (TPVI) has not been studied.
- The Geometric Orifice Area indexed by the BSA had the best overall model quality and its optimal cut-off value of iGOA was 1.25 cm2/m2.
- Both PPM and significant residual RVOT gradient ≥ 15 mmHg after TPVI were significantly associated with the need of re-intervention (p < 0.05).
- Based on the proposed cut-off value of iGOA 1.25 cm2/m2, the authors made a Table (Table 1) which can be used as a reference value of the Melody stent valve diameters based on BSA and eccentricity index.
Commentary from Dr. Varun Aggarwal (Minneapolis, MN, USA), section editor of Congenital Heart Disease Interventions Journal Watch:
Patient prosthesis mismatch (PPM) means that the effective Geometric Orifice Area (GOA) of the prosthetic valve is smaller than of a normal human valve (1). The outcomes of transcatheter aortic valve placement have been shown to be affected by the GOA of the valve (2, 3). This however, has not been well studied for transcatheter pulmonic valve implantation (TPVI). In this paper, Takajo D et al (4) performed a single center retrospective review of 101 patients who underwent transcatheter Melody valve placement in the right ventricular outflow tract from 2010 to 2020.
The GOA was calculated with the ellipse formula based on the assumption that the measured narrowest diameters in two projections represent the major and minor axis of the orifice area: GOA = p*(a/2)*(b/2), Figure 1. The GOA was indexed to the BSA, weight and height to derive iGOA (cm2/m2), iGOA (cm2/kg), and iGOA (cm2/m), respectively. Significant RVOT residual gradient (≥ 15 mmHg) was observed in 31 patients (40%). The narrowest diameter in either AP or lateral views was 16.1±2.4 mm. There were 30 patients (30%) having the eccentricity index >1.1. The measured GOA was 2.22±0.67 cm2 and iGOA was 1.42±0.48 cm2/m2. There was significant negative correlation between the post-TPVI residual RVOT gradient and iGOA (cm2/m2) (Pearson correlation -0.620, p < 0.001). The iGOA indexed by the BSA had the best overall model quality (area under the curve 0.873, p < 0.001, Figure 2) and its optimal cut-off value of iGOA was 1.25 cm2/m2. Based on the cut-off value of iGOA, the cohort was divided into two groups: PPM group (n = 42, iGOA < 1.25 cm2/m2) and non-PPM group (n = 59, iGOA ≥1.25 cm2/m2).
Over the mean follow up period of 6.9±2.7 years, 22 patients (22%) required re-interventions (16 transcatheter, 11 surgical, and both in 5 patients). On the Kaplan-Meier survival analysis, both PPM and significant residual RVOT gradient ≥ 15 mmHg were significantly associated with the need of re-intervention (p < 0.05, Figure 3). The final multivariable model showed that the significant predictors were PPM (hazard ratio 2.67, p = 0.021) and homograft (hazard ratio 2.85, p = 0.022). Abnormal eccentricity index was not associated with the presence of PPM. Neither the Ensemble system size nor eccentricity index had no effect on the need of reintervention at follow-up. Based on the proposed cut-off value of iGOA 1.25 cm2/m2, the authors made a Table (Table 1) which can be used as a reference value of the Melody stent valve diameters based on BSA and eccentricity index. This is the first data depicting the importance or GOA and PPM in transcatheter pulmonary valve implantation. These factors should be factored into consideration by operators while performing TPVI using Melody valve.
Figure 1. Measurement of geometric orifice area in the transcatheter pulmonary valve implantation. The narrowest valve stent diameter is measured in anteroposterior (AP) and lateral views (4).
Figure 2: Receiver operator characteristic curve analysis to identify the optimal cut-off value of indexed geometric orifice area (iGOA) by body surface area, weight and height, to detect the significant RVOT residual gradient (≥ 15 mmHg) in transcatheter pulmonic valve implantation(4).
Figure 3: Kaplan-Meier survival curve showing the freedom from the re-intervention in 101 patients undergoing transcatheter pulmonic valve implantation using Melody valve, based on (A) residual right ventricular outflow tract (RVOT) gradient and (B) patient prosthesis mismatch (4).
Table 1: Clinical guide for the Melody valve stent diameter to avoid the patient prosthesis mismatch based on the body surface area (BSA) and eccentricity index, using the cut-off value of the indexed geometric orifice area (GOA) of 1.25 cm2/m2 (4).
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2. Pibarot P, Clavel MA. Prosthesis-Patient Mismatch After Transcatheter Aortic Valve Replacement: It Is Neither Rare Nor Benign. J Am Coll Cardiol. 2018;72(22):2712-6.
3. Dayan V, Vignolo G, Soca G, Paganini JJ, Brusich D, Pibarot P. Predictors and Outcomes of Prosthesis-Patient Mismatch After Aortic Valve Replacement. JACC Cardiovasc Imaging. 2016;9(8):924-33.
4. Takajo D, Forbes TJ, Kobayashi D. Impact of Patient Prosthesis Mismatch on the Outcome of Transcatheter Pulmonic Valve Implantation. Am J Cardiol. 2021;151:93-9.