Takajo D, Forbes TJ, Kobayashi D. Am J Cardiol. 2021 Jul 15;151:93-99. doi: 10.1016/j.amjcard.2021.04.022. Epub 2021 May 27.PMID: 34053630
Take Home Points:
- A pulmonary valve indexed geometric orifice area of 1.25 cm2/m2 was the optimal value for predicting a residual RVOT gradient of ≥ 15 mmHg and need for reintervention.
- PPM is a strong predictor of the need for re-intervention and should be taken into account when planning TPVI to ensure optimal patient outcomes.
Commentary from Dr. Konstantin Averin (Edmonton), catheterization section editor of Pediatric Cardiology Journal Watch:
Patient-prosthesis mismatch (PPM) – a situation in which a prosthetic valve is smaller than a normal/native valve – is known to adversely affect outcomes in trans-catheter aortic valve implantation. This has not been systematically studied in patients undergoing trans-catheter pulmonary valve implantation (TPVI). The authors sought to define PPM with an optimal cut-off value using an indexed geometric orifice area (iGOA = [π x (a/2) x (b/2)]/BSA); and assess its effect on re-interventions.
From 2010 to 2020 101 patients were included (Sapien valves, bilateral Melody valve and Melody in LV-PA conduit were excluded) – median age 21.3 ± 10.2 years with 38 patients less than 16 years of age. The mean GOA was 2.22 ± 0.67 cm2 and iGOA was 1.42 ± 0.48 cm2/m2 with a significant negative correlation between post-TPVI residual RVOT gradient and iGOA. An ROC analysis identified an iGOA of 1.25 cm2/m2 as the best cut off for predicting a residual RVOT gradient of ≥ 15 mmHg. The cohort was then divided into 2 groups, those having PPM (n = 42, iGOA < 1.25 cm2/m2) and non-PPM (n = 59, iGOA ≥ 1.25 cm2/m2); unsurprisingly patients with PPM had a higher residual RVOT gradient post-TPVI. Over a mean follow up period of 6.9 ± 2.7 years, 22 patients (22%) required re-interventions. Residual RVOT gradient ≥ 15 mmHg and PPM were significantly associated with a need for re-intervention (Figure).
The authors conclude that PPM is a strong predictor of the need for re-intervention and should be considered when planning TPVI to ensure optimal patient outcomes. They provide a table (see below) to easily determine minimal stent diameters to ensure an iGOA ≥ 1.25 cm2/m2. The concept of PPM can help providers determine whether anticipated final conduit diameters will be adequate or will predispose patients to an unacceptably high risk of re-intervention. This becomes even more relevant as providers push to dilate surgical conduits beyond their nominal diameters and consider patients for valve in valve type procedures with implant of second and third trans-catheter valves.