The Never Ending Saga Of Bypasses And Stents

by Frank H Eeckman, MD PhD
Centient Biotech Investor



Before stents, there were bypass surgeries. The Mayo Clinic calls them the gold standard surgical treatment for coronary artery disease. Their popularity soared near the end of the last century until it seemed one could never get enough bypasses. Surgeons and hospitals made front page news announcing the number of bypasses they could stitch into one patient. It seemed nothing could stop progress in medicine. All that, despite the fact that there had never been a study showing any survival benefit for the procedure.

But what common sense could not cure, competition did. Bypass surgeries were bypassed by a simple mechanical device, called the stent. Stents were developed to cure the main problem with angioplasty, a less invasive method of restoring blood flow to the heart. Whereas bypass surgery - as the name indicates - uses another vessel to bypass a clogged or partially obstructed vessel, angioplasty used a balloon to force the diseased vessel open again. And whereas bypass surgery is an open heart surgery, angioplasty involves nothing more than putting a catheter in a large vein and guiding it to the coronary artery.

But many vessels would close soon after angioplasty, a process called restenosis. And then someone had the bright idea that a wire metal cylinder could be used to keep the vessel open. In came the stent and with it, angioplasty began to take patients away from cardiothoracic surgeons. But early stents, also known as bare metal stents, since they were nothing than a metal mesh, did not alleviate all restenosis. Whereas they took care of early blockage, a slower process of cell growth could still obliterate the vessel over time. To combat that process, a drug was added to the stent that inhibits cell proliferation. And so, the drug-coated stent was born.

The drug-coated stent was a clear winner. Every single device company jumped in, creating the largest device market ever - drug coated-stents. And at some point it seemed stents were going to conquer the carotid market too. Companies rushed to get carotid stents approved. Carotid stents aim to restore the circulation to the brain by removing a frequently occurring narrowing of the (carotid) artery in the neck.

Carotid bypass surgery, and its less well known variant, temporal to middle cerebral artery bypass surgery, had never enjoyed the same success as cardiac bypass. The results simply were not there. Not that the cardiac results were any better, at least not in terms of life-expectancy, but cardiac always had one winning ace. Bypass surgery relieves symptoms, and that is golden as far as the patient is concerned. While some will attribute this to placebo - double blind surgeries are hard to do and would be ethically troublesome - the fact remains that cardiac bypasses work for the patient. But let's go back to stents.

Stents are especially popular in the US, the largest and wealthiest health care market. Almost 1 million Americans get stents every year. The widgets were so successful they led to a fierce take-over battle for Guidant, between Boston Scientific (BSX) and Johnson and Johnson (JNJ). Abbott (ABT) has its own version and refrained from entering into the battle. Despite long-standing quality issues, Guidant fetched a huge premium, and the battle was especially bloody. But it has been all downhill from there for BSX. The quality issues started haunting the new company. And then came studies showing that drug coated stents may negatively affect survival compared to bare metal stents. And now there is the ultimate bad news. Although it is hardly "news."

Reports from a trial called COURAGE show that stents, much like bypass surgery do not improve survival or the risk of further heart attacks compared to drug treatment. Angioplasty and stents do improve blood flow to the heart, just like bypass surgery does. But, as is true for bypass surgery, improved circulation does not affect life expectancy or recurrence of heart attacks. That sounds very counter intuitive to many but it has been confirmed more times than anyone can remember. And, much like bypass surgery, stents do alleviate symptoms. The trial confirms results obtained in earlier, smaller trials.

The report was not well received by the stent industry. Companies like JNJ and BSX especially, which derive large amounts of revenue from stents, were hard hit even before the news was announced. The hit follows an earlier setback that occurred when the news about drug coated stents was released. Companies had rebounded a bit since, but the new studies are potentially even more damaging.

However, it remains to be seen what will happen. As mentioned, studies in the 80s and 90s showed similar results for bypass surgeries, but the reports did not affect the number of surgeries conducted. Quite to the contrary. Bypass surgery remained highly popular, and surgeons were quick to find flaws in all studies that failed to show benefits. They pointed out technicalities and claimed follow up was not long enough. Nothing could do away with bypass, it seemed. Only the competition with angioplasty and stents ultimately led to a marked decline in bypass surgeries.

It is possible that the stent industry can shrug off the news in a similar fashion. After all, there is the upbeat finding that patients do benefit symptomatically. And symptoms of heart disease are not very pleasant. Nobody likes to be short of breath or have chest pain. Many may consider it worth their while to get a stent just to feel better. Especially if the procedure is going to stay reimbursed.


Source: CentientInvestor.com



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