A valvular sleeve (14) for valvular prostheses includes a tubular body extending between an inflow end (IF) and an outflow end (OF), with the tubular body including an inner tubular portion (141) and an outer tubular portion (142) surrounding the inner tubular portion (141). The inner (141) and outer (142) tubular portions may be formed of a sheet member folded at said outflow end (OF). A prosthetic valvular device (10) includes such a valvular sleeve (14) coupled with a stent (16), with the stent (16) possibly extending between the inner portion (141) and the outer portion (142) of the valvular sleeve (14).
