Stents

By pjain      Published Oct. 27, 2019, 12:08 a.m. in blog Health   

Stents 101

Drug-coated stents, Efficacy and Safety

Heart experts warn on safety of drug-coated stents

By Ben Hirschler, European Pharmaceuticals Correspondent

BARCELONA (Reuters) - Drug-coated stents -- tiny, wire-mesh tubes used to prop open diseased arteries -- may increase the risk of potentially fatal blood clots, researchers said on Sunday.

Up to 6 million patients worldwide have received coated, or "drug-eluting," stents since they were launched in 2002, creating a $5-billion-a-year business for market leaders Boston Scientific Corp and Johnson & Johnson.

But a meta analysis of results from past clinical trials of first-generation, drug-coated stents presented at the World Congress of Cardiology showed these patients had a greater risk of heart attack or death than patients given a bare metal stent.

The increased relative risk was greatest for J&J's Cypher stent, at a statistically significant 38 percent, said Dr Edoardo Camenzind of Geneva's University Hospital.

For Boston Scientific's Taxus stent the increased risk was 16 percent, but this did not meet statistical significance.

The actual risk of death or heart attack was still low in both groups, at 6.3 percent for patients given Cypher and 2.6 percent for Taxus. But because drug-coated stents are so widely used, thousands of patients could be affected.

Dr Salim Yusuf of Canada's McMaster University said the findings were "disconcerting."

Drug coating has proved hugely popular because it prevents arterial scarring after a stent is implanted, which may cause arteries to narrow again in a process known as restenosis.

However, the drug coating delays healing round the stent, creating a risk of clots forming, which can trigger a heart attack.

The real worry is what happens after a year or more, with evidence growing that the risk of late stent thrombosis continues long after original treatment.

Late stent thrombosis has emerged as a major issue at the conference and a majority of doctors, during a session on stents, raised their hands when asked if they saw it as a problem.

The latest research follows an earlier Swiss study that found the rate of heart attacks and deaths was more than three times higher in patients with drug-coated stents who stopped taking blood-thinning drugs than those who had bare-metal ones.

Drugs like aspirin and Sanofi-Aventis SA's Plavix are generally prescribed for a few months for patients given drug-coated stents but cardiologists are now debating whether they should be given longer term to prevent thrombosis.

Denis Donohue, vice-president of clinical and regulatory affairs at J&J's Cordis devices unit, said late stent thrombosis was an issue but there was not a clear safety signal.

The company's own data showed long-term mortality rates of 6.5 percent for patients with a Cypher stent against 5.1 percent for bare metal stents, but this was not a statistically significant difference.

Novel stent may stimulate natural heart bypasses

Dutch doctors said on Sunday they had developed a novel drug-coated stent to stimulate the growth of natural heart bypass arteries, potentially offering a new way to ensure blood supply to sick patients' hearts.

The device has yet to be tested on humans but tests in animals found it almost doubled the blood flow in small collateral arteries compared to treatment with a conventional stent.

Stents are tiny, wire-mesh tubes that are use to prop open the arteries.

Newer drug-coated stents, which are designed to prevent arterial scarring, have grown hugely in popularity in the last three years and now generate annual sales of more than $5 billion.

Rather than simply focusing on the main coronary arteries, the experimental Dutch stent is designed to help smaller ones develop, enabling them to take over the function of narrowed or blocked ones.

It works by releasing the drug TGF-beta1, which makes arteries grow faster and increases their diameter, Dr Sebastian Grundmann of Amsterdam's Academic Medical Center told the World Congress of Cardiology.

Further pre-clinical testing is needed before the first patients can be treated with the new device.

But Grundmann believes the system could eventually become an important treatment option for patients with complex heart disease for whom bypass surgery is difficult or impossible.

Medtronic heart device as effective for diabetics Sun Sep 3, 9:40 AM ET

BARCELONA (Reuters) - Medtronic Inc's cardiac resynchronization therapy (CRT) is equally effective for heart patients whether or not they have diabetes, researchers said on Sunday.

CRT, an implantable device, resynchronizes the contractions of the heart's ventricles by sending electrical impulses that help it pump blood more efficiently.

More than 200,000 patients with heart failure around the world have been fitted with a CRT device manufactured by either market leader Medtronic or one of its competitors.

The latest findings, which come from a sub-analysis of the large CARE-HF clinical study, were presented at the World Congress of Cardiology.

"From previous CARE-HF data, we already knew that CRT improves survival in heart failure patients," said Dr Uta Hoppe of the University of Cologne, Germany.

"With these new data, we now have proof that CRT is beneficial in heart failure patients with different co-morbidities, including those at risk of sudden cardiac death and patients with diabetes."

The latest data showed that CRT decreased the risk of heart-failure death by 45 percent and sudden cardiac death by 53 percent.

Importantly, the mortality rate in patients with diabetes was reduced by 39 percent, comparable to the 40 percent reduction seen in patients without diabetes.

Diabetes and heart failure often coexist, reflecting the vulnerability of diabetics to cardiovascular disease.

Patients with diabetes have an up to five-fold increased risk of developing heart problems.


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