Cow valve heart implant hailed as a breakthrough

A new type of heart valve made with cow tissue and inserted by catheter was hailed as a major breakthrough that could eliminate the need for open heart surgery in some patients, United States doctors said on Sunday.

The method is aimed at high-risk patients who suffer from severe aortic stenosis, a clogged valve that impedes the pathway of oxygen-rich blood by making the heart work harder to pump blood through a narrowing opening.

The condition affects 9% of Americans over 65. Without treatment, up to half of patients die within two years.

The technique of inserting the bioprosthetic valve through a tube in the artery is less invasive than conventional surgery and showed similar survival rates to conventional surgery, but also raised the risk of stroke and other major heart complications.

The research was part of the multi-year PARTNER study, the world’s first randomized trial comparing the two methods, and was showcased at the American College of Cardiology conference in New Orleans.


“The progress has been quite dramatic over several years,” said Craig Smith, chair of the Columbia University College of Physicians and co-principal investigator on the study.

The method lowered costs involved with rehospitalisation in frail, elderly patients and was found to increase life expectancy by as much as 1,9 years, said the research.

Investigational device
The process is already being done in Europe but has yet to gain Food and Drug Administration approval in the US, where the valve is considered an investigational device.

“You are all witnessing history in the making,” said David Moliterno, professor of medicine at the University of Kentucky.

“This probably will be seen as one of the biggest steps in cardiovascular medicine, as far as intervention is concerned, potentially in our lifetime,” said Moliterno, who was not involved in the study.

After balloon angioplasty and the invention of stents, “this will be seen as the next major turning point”, he said.

The study compared results among 699 patients with a median age of 84, who were randomly assigned to either transcatheter aortic valve replacement (TAVR) or open heart surgery to replace the aortic valve (AVR).

The TAVR process involves taking a wire mesh stent that holds three stitched-in valve flaps made of cow tissue, and inserting that into the heart via a catheter in a leg artery or under the rib cage.

The bioprosthetic, called the Edwards SAPIEN heart valve, is made by Edwards Lifesciences in California.

The valve is treated with an anti-calcium building agent that helps cut back on the causes of stenosis. It is not yet available on the US market.

Early results from the study at the 30-day marked favored the catheter insertion of the bioprosthetic, showing a death rate of 3,4% compared to 6,4% for the open heart surgery method.

Death rates evened out over time and were similar at one year.

Those in the catheter-group also saw lower risk of major bleeding (9,3% compared to 19,3% in surgery patients) and irregular heart rhythm (8,6% compared to 16% in the other group).

“These results clearly show that TAVR is an excellent alternative to surgical AVR in high-risk patients,” said Smith.

However, the new method carried significantly higher risk of “major vascular complications,” at a rate of 11% after TAVR compared to 3,2% in patients who underwent conventional surgery.

Major stroke risk was also higher in TAVR patients — 3,8% versus 2,1% at the 30-day mark and 5,1% versus 2,4% after one year.

Smith declined to elaborate about the suspected causes of stroke in patients who underwent TAVR, but said the subject was being studied and would be addressed at a future conference on thoracic surgery.

Both the valves typically used in open heart surgery and the type used in the TAVR method are made with cow tissue, or bovine flaps, but the open heart surgery valves are bulkier, Smith said.

The catheter-inserted valves are smaller in size but have a slightly larger opening than the heart surgery valves.

A next-generation device is being formulated that includes some improvements to the design and can be inserted through a smaller catheter, researchers said. — Sapa-AFP

Subscribe to the M&G

These are unprecedented times, and the role of media to tell and record the story of South Africa as it develops is more important than ever.

The Mail & Guardian is a proud news publisher with roots stretching back 35 years, and we’ve survived right from day one thanks to the support of readers who value fiercely independent journalism that is beholden to no-one. To help us continue for another 35 future years with the same proud values, please consider taking out a subscription.

Related stories

No mention of Africa when it comes to US foreign policy

During pre-election debates in the United States, very little has been said on how they view one of the world’s largest markets — which, in turn, is determined to come into its own

Catholic NGO boss accused of racism and abuse in Sudan

The aid worker allegedly called his security guard a ‘slave’

Fake trafficking news targets migrants

Exaggerated reports on social media of human trafficking syndicates snatching people in broad daylight legitimate xenophobia while deflecting from the real problems in society

How US foreign policy under Donald Trump has affected Africa

Lesotho has been used as a microcosm in this article to reflect how the foreign policy has affected Africa

The challenges of delivering a Covid-19 vaccine in Africa requires a new approach

It is imperative that we train healthcare workers and participate in continent-wide collaboration

Spain detains software creator McAfee wanted in US

The announcement of his arrest comes a day after US prosecutors released an indictment against McAfee for allegedly failing to report income
Advertising

Subscribers only

The shame of 40 000 missing education certificates

Graduates are being left in the lurch by a higher education department that is simply unable to deliver the crucial certificates proving their qualifications - in some cases dating back to 1992

The living nightmare of environmental activists who protest mine expansion

Last week Fikile Ntshangase was gunned down as activists fight mining company Tendele’s expansions. Community members tell the M&G about the ‘kill lists’ and the dread they live with every day

More top stories

Fifteen witnesses for vice-chancellor probe

Sefako Makgatho University vice-chancellor Professor Peter Mbati had interdicted parliament last month from continuing with the inquiry

Constitutional Court ruling on restructuring dispute is good for employers

A judgment from the apex court empowers employers to change their workers’ contracts — without consultation

Audi Q8: Perfectly cool

The Audi Q8 is designed to be the king in the elite SUV class. But is it a victim of its own success?

KZN officials cash in on ‘danger pay for Covid-19’

Leadership failures at Umdoni local municipality in KwaZulu-Natal have caused a ‘very unhappy’ ANC PEC to fire the mayor and chief whip
Advertising

press releases

Loading latest Press Releases…

The best local and international journalism

handpicked and in your inbox every weekday