一個新的研究成果顯示低損傷瓣膜搭橋是一個安全有效在高風險的高齡主動脈狹窄患者中替代傳統的心臟瓣膜置換手術的方式。
這項研究稱，一個為狹窄的大動脈瓣膜搭橋的外科手術，要好于瓣膜置換手術，并能有效的修復血液從心臟流到身體的其他部位。研究者稱這個過程為大動脈瓣膜搭橋，這是一個對高風險的有主動脈狹窄癥狀的高齡患者重要的治療選擇。
在主動脈狹窄病例中，鈣質沉淀使得主動脈瓣膜狹窄，損害了心臟的供血能力。在瓣膜置換手術中外科醫生打開胸腔會使心臟停止跳動約90分鐘，打開主動脈切除舊的瓣膜并且縫入一個新的。搭橋的過程，無論如何是一個危害最小的手段而且不必停止心臟跳動。
“因為主動脈瓣膜置換在高齡患者中可能存在的風險的，幾乎有60%的顯示主動脈狹窄的征兆患者不能進行外科手術，”這項研究的負責人James S. Gammie談到，他主張這些病人可以從低損傷手術過程中受益。
為了給這些狹窄的主動脈瓣膜搭橋，外科醫生們從1970年起就在改良手術過程。大多數從心臟流出的血液通過軟管轉移到替代的瓣膜，其位置是靠近左心室的頂端到主動脈。這個外科手術工作通過兩肋間的切口進行。在早期的案例中，需要一個大的切口，這個過程在當時得到了修正。目前一個三英寸的切口就足夠了。
在2003-2007年中，31例高風險的主動脈狹窄患者進行了這種外科手術，患者平均年齡81歲，其中很多患者還有其他病癥，幾乎一半的患者拒絕傳統外科手術治療。在進行手術的初期，4位患者沒能在手術后幸存，目前連續進行的16例手術沒有死亡發生。
這個手術和主動脈心臟瓣膜置換手術傳統療法治療心臟血液流動障礙一樣有效。因為被損害的主動脈瓣膜仍舊在相應的部位。一些血液流動繼續流過心臟瓣膜流出。但是外科血液流動劑量顯示，在大多數患者中大約70%的心排血量通過新的橋接流動的。

Stenosis: Valve Bypass Instead of Replacement

A new study shows that the minimally-invasive valve bypass is a safe, effective alternative to conventional valve replacement in high-risk elderly patients with aortic stenosis. 19/09/2008

A surgical procedure that bypasses a narrowed aortic valve, rather than replacing it, effectively restores blood flow from the heart to the rest of the body, says a new study. The researchers conclude that the procedure, called aortic valve bypass, is an important treatment option for high-risk elderly patients with a condition called aortic stenosis.
In aortic stenosis, calcium deposits narrow the aortic valve and impair the heart's ability to pump blood. During valve replacement, the surgeon opens the chest, stops the heart for about 90 minutes, opens the aorta, cuts out the old valve and sews in a new one. The bypass procedure, however, can be performed in a minimally invasive way without stopping the heart.
"Because of the possible risks associated with aortic valve replacement in the elderly, almost 60 percent of patients with symptoms related to aortic stenosis are not referred to surgery," says lead researcher James S. Gammie. These patients could benefit from the minimal-invasive procedure, Gammie argues.
In order to bypass the narrowed aortic valve, surgeons have refined a procedure from the 1970s. Most of the blood flow from the heart is diverted through a tube containing a standard replacement valve that is placed near the apex of the left ventricle to the aorta. The surgeons work through an incision between two ribs. During the first cases, a large incision was needed. However, the procedure was modified this year, so that a three-inch opening is enough.
Between 2003 and 2007, the surgeons treated 31 high-risk aortic stenosis patients with aortic valve bypass surgery. Many of the patients also had other conditions. The average age was 81, and nearly half had been refused conventional surgery. Early in the series, four of the 31 patients did not survive the procedure, yet there were no deaths among the most recent 16 consecutive patients.
The procedure was as effective as conventional aortic valve replacement surgery at relieving the obstruction of blood leaving the heart. Because the impaired aortic valve was left in place, some blood flow continued through that valve. But postsurgical blood flow measurements indicated that in most patients, approximately 70 percent of cardiac output flowed through the new bypass.