Percutaneous pulmonary Melody^® valve implantation in small conduits

The Melody^® pulmonary valve has received approval for the treatment of dysfunctional right ventricular (RV) outflow tract conduits ≥16mm.

To investigate technical and clinical outcomes in patients who underwent percutaneous pulmonary valve implantation (PPVI) in conduits ≤16mm.

Eleven patients were enrolled retrospectively between 2000 and 2015 in a cardiac referral centre.

The PPVI indications were obstruction (n=5); regurgitation (n=1); and mixed lesions (n=5). Pre-stenting was performed during the procedure in seven cases. Three of the remaining four patients had previous stent implantation. The mean maximal dilatation balloon diameter/surgical initial diameter ratio was 1.3. Procedural haemodynamics showed a decrease in peak RV to pulmonary artery gradient (mmHg) from 50 (14-86) to 11 (5-23) (P<0.001), in RV systolic pressure (mmHg) from 69 (35-110) to 40 (25-50) (P=0.006) and in RV/aortic systolic pressure ratio from 0.8 (0.4-1.0) to 0.4 (0.3-0.6) (P=0.004). Acute device-related complications occurred in four patients (36.4%): two confined conduit tears managed with placement of a covered stent; and two vascular access complications. Mean follow-up after PPVI was 3.9 years (41 days to 6.7 years). At last follow-up, one patient had undergone surgical conduit replacement for recurrent conduit stenosis, one had percutaneous pulmonary valve dilatation and two had developed bacterial endocarditis and undergone surgical conduit replacement. Freedom from valve dysfunction at 1, 2 and 3 years was 91%, 91% and 82%, respectively.

PPVI is feasible in small conduits ≤ 16mm with good procedural and early haemodynamic results, postponing the need for surgery. These results are not sustainable over time. Larger studies are needed to determine if bare-metal stent implantation as a bridge to surgical replacement provides the same results in this specific population.