經心導管置換肺動脈瓣膜

Transcatheter Replacement of Pulmonary Valve

法洛氏四重症手術後常常會產生肺動脈瓣逆流，尤其用到跨瓣補片時，逆流會較為嚴重。長期肺動脈瓣逆流會導致右心室擴大，右心室功能衰竭心律不整，需要及時把瓣膜換掉，最近的研究認為右心室舒張末期容積比大於150－160 cc/m2，或右心室收縮末期容積大於83－90 cc/m2或瓣膜逆流指數>30％，右心室的射出分率（RVEF）<45％或有心臟症狀，須把瓣膜換掉。傳統的換瓣方式是開刀置換，最近發展出心導管置換肺動脈瓣膜的技術，得到很好的成績，最廣被使用的瓣膜是Melody valve。Melody valve是用牛頸靜脈瓣縫在CP stent上，再架在BIB balloon（balloon-in-balloon）上，置放的方法是另一支CP stent 先做pre-stenting，然後再用傳送系統把Melody valve送到定位再張開BIB balloon，不過由於Melody valve只適用於右心室流出道小於22 mm，若大於22 mm則需使用Edwards Sapien valve或Venus P-Valve，Venus P-Valve是種自膨式的支架帶有豬心包膜做的瓣膜，可以放在肺辦環小於34 mm且無左肺動脈狹窄的病人，二年來我們有七例Melody valve成功經驗，Venus P-Valve十一例的經驗，短期效果相當好。 Pulmonary regurgitation (PR) is quite common after surgical repair of tetralogy of Fallot. PR can be severe, if a transannular patch had been used. Long standing severe PR may result in right ventricular dilatation, heart failure and arrhythmia. Recent studies showed the pulmonary valve should be replaced when either the right ventricular end-diastolic volum >150~160 c.c./m2 , right ventricular end systolic volume >83~90c.c./m2 or pulmonary regurgitation index >30 %, or right ventricular ejection fraction<45%. Surgical replacement of pulmonary valve is the traditional method. Recently, transcatheter replacement of pulmonary valve become an alternative to surgery. Melody valve is the most popular valve used. Melody valve is made of calf jugular venous valve which is sewed on a Cheatham Platinum stent (CP stent). Pre-stenting of pulmonary annulus is required using a CP stent. Then melody valve is mounted on a balloon-in-balloon (BIB) catheter. It is then delivered to pulmonary annulus and was inflated to the desired size using a BIB catheter. However, melody valve can be used only in patients with a pulmonary annulus less than 22 mm. When the pulmonary annulus is greater than 22 mm, Edwards Sapien valve or Venus P-Valve should be used. Venus P-Valve is a self-expandable valve made of porcine pericardium and can be used in patients with a pulmonary valve annulus less than 34 mm and without left pulmonary artery stenosis. In the past 2 years, we have implanted melody valve in 7 patients and Venus P-Valve in 11 patients. The short-term outcomes are quite well.