心臓しんぞう人工じんこう弁べんカテーテル手術しゅじゅつ長期ちょうき治療ちりょうデータ調査ちょうさへ

The group at Osaka University Hospital investigated the progress of surgeries in which artificial valves were implanted in the heart using catheters, and found that within 10 years, there were nearly 30 cases where the valve did not function properly, requiring reoperation or resulting in death.

This surgery is becoming widespread mainly among the elderly, but the group has decided to conduct a survey with medical institutions nationwide, as they believe there is not enough long-term treatment outcome data.

This surgery involves implanting an artificial valve through a thin tube called a catheter inserted into blood vessels such as those in the thigh, for patients with a condition called aortic valve stenosis, in which the heart valve does not open properly and blood flow is restricted. More than 10,000 such procedures are performed annually across the country, mainly among the elderly.

Because it has rapidly become widespread over the past decade as it is less invasive than open-chest surgery, the long-term treatment outcomes in Japan are still not well understood.

For this reason, a group at Osaka University Hospital reviewed more than 1,500 surgeries performed in the hospital and found that, four to nine years after the procedure, 28 patients required reoperation because the implanted valve was not functioning properly and blood flow was restricted.

Of these, 15 people’s symptoms worsened and they died within a year.

The group has decided to start a study, in collaboration with about 40 hospitals nationwide, to track patients progress over a period of 10 years, stating that data comparing treatment outcomes with open-chest surgery is necessary when choosing a surgical method.

Dr. Koichi Maeda, specially appointed lecturer at Osaka University Graduate School of Medicine, said, It was groundbreaking and rapidly became widespread because even patients with physical limitations could receive it, but the lack of sufficient domestic data on long-term treatment outcomes is a problem.

I want to collect data to determine which patients it should be recommended to, they said.

The procedure of implanting an artificial valve in the heart using a catheter is called TAVI, and it has rapidly become widespread in Japan over the past ten years.

The clinical guidelines revised in 2020 by the Japanese Circulation Society and others state that, when choosing between TAVI and open-chest surgery, all patients should be given a thorough explanation based on the latest information, and the decision should be made considering factors such as age, physical condition, and patient preferences.

The guidelines state that there is no solid evidence at this time, and, as an age guideline, recommend prioritizing TAVI for those aged 80 and over, and open-chest surgery for those under 75.

Also, it is said that for those aged 75 to under 80, the decision will be made through discussion by the medical team.

The number of domestic surgeries has continued to increase since public health insurance coverage began in 2013, and according to surveys by related academic societies, it surpassed open-chest surgeries five years ago, with over 16,000 cases performed last year.

Regarding the survey that Osaka University and others will begin, the council formed by academic societies involved in TAVI treatment stated, Since it is a new treatment that has only been approved by the government for a little over ten years, we believe that such a survey is important.

We have continued to urge the medical team to thoroughly discuss the indications for surgery.

We believe that depending on the survey results, there is a possibility that the content of the medical guidelines may be affected, they commented.

Cases in which reoperation became necessary after undergoing TAVI have been reported overseas as well. According to a paper analyzing cases registered in the database of the Society of Thoracic Surgeons in the United States, there were approximately 5,500 such cases across the country in the ten-plus years up to March 2023.

In the United States, guidelines and other regulations changed between 2019 and 2020, expanding the indications for surgery, and the main target patients are now considered to be those aged 65 and older.

The paper points out that there was a rapid increase in cases requiring reoperation during this period.