The almighty cardiac stent

Mr. Jones had the scare of his life. At only fifty-six years of age he never expected to have significant build-up of cholesterol in his arteries, let alone chest pain. He first noticed the chest pain while mowing his lawn and then again whenever he over-exerted himself. Eventually, although not noticing a change in the chest pain, Mr. Jones could no longer ignore it. He met with his primary care doctor who, concerned that it was related to his heart, referred him to a cardiologist.

The cardiologist shared the concern and, given the high suspicion, promptly ordered a cardiac catheterization – a procedure in which a wire is traversed, usually from the right groin, up to the heart to inject the arteries with dye and evaluate for blockages. Mr. Jones’ catheterization showed various small build-ups of cholesterol but also one blocking over 70% of an artery.

Judging this blockage as the likely cause of Mr. Jones’ symptoms, the interventional cardiologist by inflating a balloon opened the artery and then expanded a stent (a wire mesh) in place to help keep it open.

(http://www.youtube.com/v/9FPapBbbS4o&hl=en&fs=1)

Afterwards the cardiologist shared with Mr. Jones the pictures of what he had done. The significantly blocked artery, now with a stent, looked quite good.

On leaving the hospital that day, Mr. Jones exhaled a sigh of relief feeling better, reassured and grateful that a significant blockage in his artery had been fixed, opened up, and that he had bought himself more time to enjoy with his family. The cardiologist left work feeling good for having helped a patient and for a job well done.

Of course, the real story is missing. The cardiologist had helped the patient, but Mr. Jones and the cardiologist may have lost the big picture that day and perhaps perpetuated a myth.

Dispelling the myth

Data from studies investigating stents for heart disease do no prove that patients with stable blockages in the arteries of their heart do better in the long term with early placement of stents than merely management by medications. That is, studies do not show that stents allow people to live longer or have fewer heart attacks than those treated with medications.

The real benefit of stents is their ability to improve symptoms, chest pain or shortness of breath, shortly after they are placed. This benefit over medications too dissipates with time. One study that looked at patients five years after either initial placement of stents or management by medications showed similar amounts of chest pain between the two groups.

Why then does the information get lost and the myth perpetuated?

Part of the reason that the myth is perpetuated is psychological - we as patients want stents to solve the problem. On being diagnosed with blockages in our arteries, faced with heart disease and our own mortality, we, like Mr. Jones, want to think actions can be taken to quickly reduce our risk of heart attacks and prolong our life. We want to sleep better. The stent that quickly and visually opens an artery and makes us feel better reinforces the idea.

The before and after pictures of the clogged artery are also visually quite compelling to doctors. Doctors want to believe. They are familiar with studies, but doctors only see real people in their office, individuals like Mr. Jones. They don’t want their patients only on average to do better, but they want Mr. Jones to do well, not have heart attacks and live longer. Placing stents and seeing a quick relief of chest pain and shortness of breath reinforces that idea to doctors as well, even if it’s inaccurate.

The interventional cardiologist on inserting the dye and diagnosing the blockage is there with a wire in Mr. Jones’ groin ready and able to open the blockage. Does he ignore the prominent blockage, not act, and remove the wire? How does Mr. Jones react? Patients appreciate feeling better right away and generally equate that with a better level of care. Imagine explaining to Mr. Jones that he will instead be only started on medications and that, despite the significant blockage in his artery, he should do just as well as his friends with stents.

The idea in medicine of not “doing something just because you can do something” can be one of the most difficult lessons for doctors to learn and for a patient to accept. As a patient who presents to a doctor with a problem and as a doctor in charge of making this person better, there is always a pressure to do something, anything. The pressure to do something, anything, however can cause people to neglect the associated risks.

Cardiologists as specialists

Specialists like cardiologists feel this pressure more than anyone. As a specialist, the expert, the cardiologist is expected to offer solutions others can’t and make everything better. If the cardiologist does nothing and/or merely adjusts medications patients may wonder why they are seeing the specialist. The patients may stop seeing the cardiologist.

Mr. Jones was referred to the cardiologist by another doctor (likely one who also specialized in internal medicine but decided not to specialize further). The cardiologist therefore may interpret the internist’s referral of Mr. Jones as an interest in doing more, seeing an intervention performed. The internist may just want assistance in adjusting medications or a second opinion but that idea may not be transmitted. An internist can adjust medications and not put in a stent just as a cardiologist can. The cardiologist may fear that if he doesn’t place a stent and merely adjusts medications, that the internist will send patients to a different cardiologist who will do more and intervene further.

What is a cardiologist without patients? The salary of an interventional cardiologist may also indirectly be tied to the number of procedures he does and the stents he places. (As an aside, I in no way want to diminish the role that cardiologists play in the care of patients.)

Stents have no role?

Does that mean patients with a blockage over 70% and stable chest pain shouldn’t have a stent placed? Clearly that is a discussion patients can only have with their doctors, but it means that if people are relying on stents to open their arteries and keep them from having fewer heart attacks and living longer, they may need to rethink their assumptions.

For future discussion: the theoretical reasons as to why stents don’t necessarily save lives or prevent heart attacks, why stress tests in asymptomatic patients are generally not recommended, and what do we know that prevents heart attacks and saves lives.

A first look at end of life issues

We have to die eventually, a fact of which we are all sufficiently aware; yet we rarely, if ever, think about how it might unfold and we certainly don’t talk about it. The lack of discussion as individuals and as a society about end of life issues adds to emotional distress and to increasing health care costs.

Imagine Grandpa of one hundred years of age whose heart has stopped. Miraculously the event is witnessed, he is resuscitated, pacemaker pads are quickly placed on his chest to keep him alive, and he is rushed to the hospital. On arrival he is in critical condition and sedated on a mechanical ventilator, and he is transferred to the intensive care unit. Grandpa can’t communicate his wishes, but if he is to survive long-term he will need an implantable pacemaker. Do we place the pacemaker?

You, as the next of kin, are now in charge of the decisions regarding Grandpa’s care. Unfortunately, Grandpa never discussed his wishes with you about what he would want done in these circumstances and never drafted a living will. Faced with the life and death decision, determining the fate of Grandpa, the decision seems clear: uphold life above all else and place the pacemaker. However, is that the best decision?

For the last five years he has suffered from worsening Alzheimer’s dementia. He no longer knows who he is or where he is. He spends his days confused, and someone feeds him, changes his diapers, and turns him so he doesn’t develop bedsores. Do we still place the pacemaker?

Are we doing Grandpa a service by placing it? He has lived a good number of years, more than many of us can dream of, and at one hundred years of age one day in the near future, whether a pacemaker is placed or not, he will likely pass on. What if he believed that he had had a great life, that his wife, friends, and neighbors had already passed and that he would one day pass from something?

Remember Grandpa already died once. His heart stopped. Modern technology merely brought him back to life, and only for this reason are we faced with these questions. His mental function and lifestyle prior to the cardiac arrest were poor, but as a result of the cardiac arrest and resuscitation efforts his mental function will likely be even worse, if he is not already neurologically devastated.

You finally decide to not place a pacemaker and, in so doing, believe that you are fulfilling what Grandpa would’ve wanted. You then discover that your younger brother Jimmy, who only now has arrived at the hospital, disagrees with you and the rest of the family and believes Grandpa would’ve wanted the pacemaker. A family debate ensues. Without truly knowing Grandpa’s wishes there is no right or wrong answer. How does the family resolve this issue? How do the doctors resolve this issue? You as the next of kin are legally empowered with making the decision, but for obvious reasons doctors, like families, prefer unanimity in these situations.

Meanwhile days pass with Grandpa still in the intensive care unit lying in bed, staring at the ceiling unresponsive, and awaiting a decision. The doctors pepper you with other questions. What would you like done if Grandpa were to go into cardiac arrest in the hospital? Would you want him to receive an electrical shock in attempts to disrupt an abnormal rhythm and rescue him? Would you want for him to again undergo chest compressions (in which, yes, if done properly ribs are cracked) in attempts to maintain circulation as he is resuscitated? Would you want a tube placed in his stomach to feed him as he is no longer able to eat on his own? Would you want to continue drawing daily blood tests?

Is this how Grandpa imagined passing away? What if instead for the last five years rather than dementia he merely suffered from severe arthritic pain that confined him to a wheelchair and about which he complained incessantly? What if instead he had been a healthy one hundred year old man? Lots of questions arise.

The lack of discussion as a society of end of life issues (hoping instead for others to address or for the issues to go away) negatively impacts us and (to be addressed further) also leads to higher health care costs and to a skewed distribution of society’s health care expenditures.

Risk by the numbers: absolute vs relative risk

“Doc, I can’t take the pain anymore,” Mrs. Wiedner said as she hobbled with a cane back to the examining room in the office. “I’ve had enough!” At eighty-six years of age she had suffered from severe arthritis in her knees for many years. “What about this Celebrex I keep hearing about? My neighbor says it works like a charm, but I hear it causes heart attacks.”

Celebrex is a pain reliever in the family of medications called COX-2 inhibitors and part of the broader group of pain relievers called non-steroidal anti-inflammatory drugs (NSAIDs) that include over the counter medications such as ibuprofen and naproxen. These medications have received widespread attention for their potential to increase the risk of heart attacks and strokes, and Vioxx, a COX-2 inhibitor, has been removed from the market.

Unfortunately all medicines (even over the counter medicines) have risks, but to understand the risks associated with a medication you first have to understand something about the numbers behind risk - a topic often neglected by patients and their doctors.

What if I told you that I have secretly developed a new drug, a potion that after only one dose insures perfect physical health. Would you be interested? Of course. Would I be rich? Probably. What if I told you that taking the drug, unfortunately, also doubles your risk of developing Alzheimer’s disease at an early age. Would you take the drug?

I assume you’re not too keen on getting early Alzheimer’s, let alone doubling your risk, but what if before taking the drug your risk of developing early Alzheimer’s is only one in a billion. Would you then be willing to double your risk of early Alzheimer’s to insure perfect health? I probably would. Sure, your risk relative to someone who didn’t take the drug would be double, but your absolute risk would only be two in a billion – a trivial number or risk to insure perfect physical health.

In selling the drug I would for full disclosure mention the increased risk of early Alzheimer’s. Though unless I wanted to scare you, rather than stating that the drug doubles a patient’s risk of early Alzheimer’s, I would state simply that it increases your risk by one in a billion. Either way I would be accurate, but why scare you?

What if, however, your risk of developing early Alzheimer’s before taking the drug is instead one in five or 20%. If the drug that guarantees perfect physical health doubles your risk of early Alzheimer’s (that is, the relative risk is again doubled), your absolute risk of developing early Alzheimer’s after taking the drug would now be two in five, 40%. With that risk for early Alzheimer’s, would you still want to take the drug? Maybe, but those odds are clearly less favorable.

Therefore understanding relative risk, knowing whether something doubles or halves your risk, is often insufficient. It is important to ask what the initial risk is and think about what the change in absolute risk really is. Never going outside may decrease your risk of being hit by a meteor or being robbed, but what is your risk to begin with? Most people would probably still decide to walk outside.

Another way to look at the numbers is to calculate the number needed to treat, the number of patients needing to take the drug to affect one person. The number needed to treat (NNT) is equal to 100 divided by the difference in absolute risk expressed as a percent. In the last example, the NNT for one additional person to develop early Alzheimer’s is 5 (100 divided by 20). In contrast, in the first example the NNT for one additional person to develop early Alzheimer’s is 10 million (100 divided by 0.00001).

Drug companies, the media, and others have their reasons for either magnifying or diminishing the perception of medications’ risks. In reading numbers it is always helpful to question what the vested interests are of those who quote you the numbers. Then you can look objectively and evaluate the numbers.

Celebrex is, therefore, an excellent example. The media has certainly stressed the potential increased risk of heart attacks from COX-2 inhibitors, but for many people the absolute risk may be low. What is Mrs. Wiedner’s risk of a heart attack to begin with? Are there other more common risks from Celebrex she should worry about? How much is the pain really bothering her? Are there alternative medications that she might consider taking? Are the risks of Celebrex to her worth the benefits? These are questions that only she can answer with the help of her doctor and understanding what the numbers really mean. Once a person understands risk, however, they can make their own decision.

Hopefully this look at the numbers behind risk assists you in having informed discussions with your doctor about medications and medical treatments.