瓣膜搭桥而不是手术替换

一个新的研究成果显示低损伤瓣膜搭桥是一个安全有效在高风险的高龄主动脉狭窄患者中替代传统的心脏瓣膜置换手术的方式。
这项研究称，一个为狭窄的大动脉瓣膜搭桥的外科手术，要好于瓣膜置换手术，并能有效的修复血液从心脏流到身体的其他部位。研究者称这个过程为大动脉瓣膜搭桥，这是一个对高风险的有主动脉狭窄症状的高龄患者重要的治疗选择。
在主动脉狭窄病例中，钙质沉淀使得主动脉瓣膜狭窄，损害了心脏的供血能力。在瓣膜置换手术中外科医生打开胸腔会使心脏停止跳动约90分钟，打开主动脉切除旧的瓣膜并且缝入一个新的。搭桥的过程，无论如何是一个危害最小的手段而且不必停止心脏跳动。
“因为主动脉瓣膜置换在高龄患者中可能存在的风险的，几乎有60%的显示主动脉狭窄的征兆患者不能进行外科手术，”这项研究的负责人James S. Gammie谈到，他主张这些病人可以从低损伤手术过程中受益。
为了给这些狭窄的主动脉瓣膜搭桥，外科医生们从1970年起就在改良手术过程。大多数从心脏流出的血液通过软管转移到替代的瓣膜，其位置是靠近左心室的顶端到主动脉。这个外科手术工作通过两肋间的切口进行。在早期的案例中，需要一个大的切口，这个过程在当时得到了修正。目前一个三英寸的切口就足够了。
在2003-2007年中，31例高风险的主动脉狭窄患者进行了这种外科手术，患者平均年龄81岁，其中很多患者还有其他病症，几乎一半的患者拒绝传统外科手术治疗。在进行手术的初期，4位患者没能在手术后幸存，目前连续进行的16例手术没有死亡发生。
这个手术和主动脉心脏瓣膜置换手术传统疗法治疗心脏血液流动障碍一样有效。因为被损害的主动脉瓣膜仍旧在相应的部位。一些血液流动继续流过心脏瓣膜流出。但是外科血液流动剂量显示，在大多数患者中大约70%的心排血量通过新的桥接流动的。

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.