心臟瓣膜手術的發展
大概往更棒的手術技巧做瓣膜修補手術
以及更好的醫療生物材質處理技術做出更棒更持久不會退化鈣化結構失效的成熟產品
各位在Youtube 上可以找出羅賓威廉斯接受電視台訪問他開二尖瓣手術的經驗
他逗趣的學心臟外科叫他選擇用塑膠的(機械瓣膜 ) 或者豬瓣膜或者牛瓣膜
他擔心他開完刀後睡覺打呼會出現豬叫或牛叫聲
影響枕邊人.....
羅賓後來沒有公布他選擇哪一種瓣膜
可是連大明星都手術了手術後還可以繼續從影拍了許多上山下水的逗趣片
證明這項手術的純熟
隨著愛德華公司發展出牛瓣膜Magna
使用先進的脫磷技術將細胞膜上的磷酸鹽去除讓身體的鈣質不易附著在瓣膜上造成
中早期的瓣膜鈣化損壞退化瓦解
讓病人必須在十年或者十五年必須接受第二次第三次的手術
這個產品引進台灣馬上引起大多數心臟外科醫師的讚賞
國外已經有將近二十年仍正常運作的牛瓣膜經驗
當然也有醫師發表出牛瓣膜早期鈣化損壞的少數報告
讓愛德華公司很難解釋他們自豪的脫磷防鈣技術怎麼在那個病人身上無效
最近
美敦力公司也發表已經在國外適用超過二十五年的第三代豬瓣膜Mosaic
在已經證實大多數患者通過十年十五年的嚴格考驗的六十五歲以上患者
使用第二代豬瓣膜只有一位發生早期損壞必須重新手術的輝煌歷史的Hancock II第二代豬瓣膜
" 塑膠支架" 及" 覆蓋布" 上
利用他們獨一專利的AOA( alpha amino oleic acid) 處理技術也成功擺脫生物瓣膜在人體容易
鈣化失效解體退化的命運
在2001年心胸外年鑑上發表的802個病人沒有人在四年內出現結構退化
Ann Thorac Surg 2001;71:S269-S272
今年在同樣的雜誌上發表超過十二年的使用經驗也是呈現絕大多數的患者接受這個新型瓣膜
可以有超過十年的使用穩定度
同樣的
在看完廠商請各大醫院生出來的商業論文後
我們還是要找一找有沒有持相法意見的病例報告
這在2009年就有聖路易斯的華盛頓醫科大學附設醫院的心臟外科女醫師
發表在她使用的122 例中發生了四例的早期瓣膜毀損的狀況
結果令人震驚
分別發生在手術後的是3-44 個月
大家都猜不透
這個手術後三個月就發生瓣膜毀損的患者是廠商處理瓣膜的問題還是開刀房小姐
或者醫師在浸泡清洗縫合過程有無失當
....
不管如何
站在病人的角度來看
再優良的新一代瓣膜即使已經在上市前做了超過十年十五年的動物實驗或者人體
試驗觀察追蹤
還是不能百分百保證它一定完美無缺
Interventional/Surgery
Surgeons report "alarmingly early stenosis" with porcine heart valve; manufacturer assures safety, efficacy
July 15, 2009
St Louis, MO - A surgeon at the Washington University School of Medicine, in St Louis, MO, says she and her colleagues have no good explanation for what they term "alarmingly early stenosis" seen in patients treated with the Medtronic Mosaic bioprosthetic valve in the aortic position. According to a brief communication they've published in the June 2009 issue of the Journal of Thoracic and Cardiovascular Surgery, Dr Jennifer S Lawton and her coauthors, prompted by an initial case of early stenosis, followed all 122 patients in whom they'd used the device, ultimately turning up four cases of severe stenosis requiring valve replacement within just three to 44 months after implantation.
Mosaic bioprosthetic heart valve [Source: Medtronic]
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Durability of the Mosaic, a third-generation porcine valve, is typically assumed to be between 10 and 15 years, Lawton told heartwire. "We did not find any other reports of this: that's one of the reasons we felt we should try to get it into the literature; we felt others should know about it."
Medtronic, for its part, says Lawton et al's finding is solely related to patient-level factors, and the company staunchly defends the safety, durability, and efficacy of its product.
Early stenosis
According to Lawton et al's report, all four valves, implanted by two different surgeons, have a "strikingly similar appearance of thickened material resulting in immobility of the leaflets."
Explanted Mosaic valve [Source: Dr Jennifer S Lawton]
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Patient-prosthesis mismatch was excluded as a possible cause, as were other patient- or procedure-related factors, Lawton told heartwire. "Explanted valves were examined by a pathologist at the Washington University School of Medicine and by a pathologist after return of the valves to Medtronic, and no cause for the stenosis could be determined in any case," they write.
Contacted for comment, however, a Medtronic spokesperson pointed out that the Mosaic is the only stented heart valve with "proven third-generation performance," with more than three decades of tissue valve design improvements behind it.
"It is the valve of choice for many cardiac surgeons throughout the world," Joseph McGrath told heartwire. "Based upon the collective body of evidence of peer-reviewed journal articles that have demonstrated satisfactory clinical results with the device, Medtronic confidently stands behind its conviction that the Mosaic heart valve offers both surgeons and patients alike a safe and efficacious product."
The Medtronic analysis of the valves—sent to the company by Lawton and colleagues—indicated that pannus (a flap of tissue or scarring) and/or thrombus was the reason for explantation in all four cases. "These events are caused by patient factors extrinsic to the valve," McGrath said. Medtronic has subsequently published a formal statement about the Mosaic's durability online in response to Lawton et al's paper [2].
Lawton is not entirely reassured, however, and says she is not using the Mosaic—it had previously been her go-to device—until she has further information supporting its safety and durability, noting that there are many other options for valve replacement. She hopes other hospitals will be prompted to review their cases and see whether this phenomenon is occurring anywhere else. "I really didn't want to subject any of my patients to a similar problem, and I honestly don't know how to prevent it, so I've been choosing different types of valves."
She added that she didn't think there was any reason for alarm in patients who had already received the Mosaic, since the numbers of patients affected is seemingly so small. "Any patients with a valve replacement should follow up regularly with their physicians, and that means an echocardiogram periodically. If they have symptoms of shortness of breath, swelling in the legs, or chest pain, they should see their doctor and obtain an echocardiogram."
An issue worth raising
Also asked to comment on the paper for heartwire, cardiothoracic surgeon Dr Jeff Tyner (Scripps Clinic, La Jolla, CA) emphasized that Lawton et al's report was "not enough to condemn the Mosaic, although it's a possible problem that you'd want to track."
He added that he himself has not used the Mosaic, because it has only eight to 10 years of data supporting its safety and durability. That said, he added, "It is a third-generation device, which means it should do very, very well long term. If others find this, however, it's a big deal. You have to wonder what the mechanism for this is."
Possible explanations, said Tyner, include underlying endocarditis (although patients with endocarditis were excluded from Lawton et al's series), subsequent chemotherapy, operator-related issues (including the kinds of rinses or other medicines/techniques used during the procedure), and finally something specific to the valve itself.
"I don't know what you do at this point other than raise the issue and get people to kind of track their patients," Tyner said. Since surgeons often do not end up following up with these patients, it's important for news of the potential problem to reach the cardiology and echocardiography communities, he added
Sources
- Lawton JS, Moazami N, Pasque MK, et al. Early stenosis of Medtronic Mosaic porcine valves in the aortic position. J Thorac Cardiovasc Surg 2009; 137:1556-1557.
- Medtronic Inc. Durability of the Mosaic bioprosthesis. July 10, 2009. Available at: http://www.medtronic.com/mosaic/response.
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