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Your present location:Home >> News >> 新闻动态 >> Industry >> [CIT2014] Hotspot Express: Exchange of China’s Experience on Transcatheter Aortic Valve Replacement (TAVR) --An exclusive interview with Professor Chen Mao of West China Hospital of Sichuan University

[CIT2014] Hotspot Express: Exchange of China’s Experience on Transcatheter Aortic Valve Replacement (TAVR) --An exclusive interview with Professor Chen Mao of West China Hospital of Sichuan University

Date:2016-11-18 21:31

China’s TAVR Industry— embarks on development for a steady progress 
TAVR is a new breakthrough in cardiology intervention. At present, it has more than 10 years of development history in Europe. With the continuous improvement of equipment, the maturing of technology and the gradual accumulation of operating experience, more and more patients with severe aortic stenosis who are not able to undergo surgical operation for valve change or have high risk of operation have benefited from this new treatment technique. In the past five years, the number of patients receiving TAVR treatment has increased exponentially. However, at present TAVR in China is still in its infancy. Since October 2010, Professor Ge Junbo of Zhongshan Hospital affiliated to Fudan University successfully completed the first TAVR in China, several large-scale heart centers in China including our hospital, (Beijing Fuwai Hospital, PLA General Hospital, the second military Medical University Changhai Hospital affiliated to Changhai Hospital Affiliated to the Second Military Medical University, the Second Affiliated Hospital of Zhejiang University School of Medicine,etc.) have carried out this technology. Because the valves with most international application experience from the American companies Edwards Sapien(balloon-expandable valve )and the Corevalve(self-expandable valve) have not been approved to be put on the domestic market, the valves for those centers’ completion of TAVR are largely sponsored by special funds allocated by each hospital. Our hospital is one of the centers that have funded TAVR with the most amount of money. In 2011, our hospital approved special fund of RMB 6 million yuan to solve the financial problems in TAVR implementation. Even so, due to the high cost of imported valves (with a unit price of more than RMB 200,000 yuan), the above-mentioned funds are only enough to support more than 20 patients. This situation greatly restricts the development of TAVR in China. Fortunately, with the support of the “Twelfth Five-Year Plan” of national science and technology support program project, the project of domestic-made Venus A-valve( Venus A Transcatheter Aortic Valve), led by Academician Gao Runlin of Fu Wai Hospital, formally entered into the clinical trial phase in September 2012. At present, the experiment is progressing well, and hopefully it will promote the rapid and healthy development of TAVR in our country, speed up the localization of TAVR prosthetic valves, and solve the bottleneck problem that restricts the development of this technology in our country.
TAVR Chinese Application Experience Exchange-- Treatment needs to be targeted for patients with unique characteristics 
At present, China has completed about 100 cases of TAVR, and the specific data is still being counted. There were a total of 33 TAVR cases completed in our hospital from April 2012 to February 2014, which was the largest number of cases completed in domestic centers.  Of these 33 patients, 22 cases were male, and 11 cases were women, with the average age of 73 years old and the main clinical manifestations of dyspnea, chest pain and syncope.  About 80% of the patients had the  heart function level of III~IV, and nearly 90% of them had at least one major disease, including chronic obstructive pulmonary disease, hypertension, coronary heart disease, atrial fibrillation, peripheral vascular disease and malignancy. All those patients were considered to have high risk of surgery and were not suitable for surgical thoracotomy to change the valve. Among them, except for one patient with poor femoral artery condition and the valve was implanted through the subclavian artery pathway, and the remaining patients received TAVR by femoral artery pathway. There were 3 patients with severe coronary artery stenosis, and we carried out percutaneous coronary intervention with TAVR in the same period. In all patients, only 1 patient after TAVR could not expand valve properly due to severe calcification of aortic valve, and the remaining TAVR operations were successful, with a success rate of 97%. Hemodynamic changes were significantly improved in all postoperative patients without acute myocardial infarction and acute renal injury. Although 2 patients (6%) respectively had a stroke immediately after the operation and in the 4th day after the operation, they recovered well and did not have serious functional damage. Permanent pacemaker were implanted in 10 patients (30.3%) with severe conduction block after operation. 1 patient had pelvic and rectus hematoma after operation, according to suggested definition of the Valve Academic Research Consortium -2 (VARC-2), this symptom can be classified as mild bleeding and mild vascular complications associated with surgical approach (the patient died 20 days later due to sudden cardiac death). At present, in the follow-up of 28 patients with post operation time exceeding 30 days (median follow-up time: 455 days; shortest: 43 days, longest: 674 days), no death or other clinical endpoints have increased.
Our TAVR fits the description of the reports in foreign literatures in terms of success rate, postoperative complication rate and survival rate. It is noteworthy that the proportion of TAVR patients in China who have had a bicuspid aortic valve deformity is nearly 70%. Bicuspid aortic valve deformity is always considered as a relative contraindication of TAVR, because of the problems involved such as the widening of aortic root and ascending aorta, extreme eccentricity of the valve annulus, the over large shape of annulus diameter, asymmetry of the leaflet shape and calcification distribution. Our initial experience shows that the treatment of symptomatic bicuspid aortic valve stenosis is feasible through TAVR for patients with high risk of operation or inability to undergo operation, but TAVR‘s long-term safety and effectiveness remains to be further evaluated.
TAVR 's popularization and application in China--Great difficulties must be overcome to carve out a wide world
The popularization and application of TAVR in China still faces great challenges. In addition to the problem of valve cost and source mentioned above, the application of TAVR in China has been restricted by the following problems.
First, at present, there is no large-scale research on the prevalence and disease burden of aortic stenosis in China, especially the calcification in the elderly, so that the state's medical and health input lacks a clear basis and guidance, which causes the ignorance of this disease to some extent.
Secondly, there are only a few foreign experiences to be consulted on how to carry out TAVR on some patients with specific anatomical features, especially those with bicuspid aortic stenosis. As mentioned earlier, bicuspid aortic stenosis has been regarded as a relative contraindication to TAVR, and the clinical trials and registration studies have also cited it as exclusion criteria, resulting in limited international experience in treating this kind of patients with TAVR. In the process of screening TAVR patients, several large centers in the country have discovered that at least half of the elderly patients with severe aortic valve stenosis who were not suitable for surgical valve change had bicuspid aortic valve pattern. Although we have gained some experience in the TAVR treatment of severe bicuspid aortic valve stenosis, further study needs to be conducted on the selection criteria of the bicuspid valve patients, the durability of the valve stent and the effect on the dilated aorta. In addition, the design of a special TAVR valve for patients with bicuspid aortic stenosis may be a future research and development direction.
Third, in order to standardize the development of TAVR in China, promote its health, steady progress, and ensure patient safety, we must refer to the European and American experience and high-quality research evidence and combine with domestic experience, to introduce a set of TAVR state standards in line with China's national conditions. With the maturing of TAVR technology and the accumulation of experience, TAVR indications have gradually relaxed. At present, TAVR has been used in foreign countries to treat Low-risk and younger patients in surgery. However, we should recognize that TAVR is still in its infancy at home, so its application must be strictly limited to patients with high risk of surgery or inability to undergo surgery. For patients ' selection and preoperative evaluation, it should be emphasized that high-quality image acquisition and accurate imaging evaluation are the key parts of TAVR success, and we must set up uniform standards to guide and standardize those parts. In addition, due to the difficulty of TAVR technology, the complication of patients’ condition, the concrete implementation of each steps including its preoperative assessment, operation and postoperative monitoring and other aspects depends on the close collaboration between a number of related professions, posing high requirements for operators and their multidisciplinary teams and supporting software and hardware requirements. So it is necessary to establish clear and specific qualification standards for TAVR physicians and the medical institutions to implement TAVR. 
 
 
This article is reproduced from International Circulation
 
 

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