Book Review: Haywire Heart

 

 

 

 

 

 

 

 

Check out the recently published “The Haywire Heart” by Chris Case, John Mandrola, MD, and Lennard Zinn.  The book is available at Amazon and other outlets.

You may recall that Case, Mandrola, and Zinn authored an article in VeloNews, entitled “Cycling to Extremes:  Are endurance athletes hurting their hearts by repeatedly pushing beyond what is normal?”  This was a terrific read.  I wrote a previous blog post sharing my thoughts about the article and about the issue of arrhythmias and endurance sport, more generally.  Their article generated much discussion in the cycling and broader endurance sports communities and the interest of readers served as the motivation for their new book.

This is a book about electrical problems in the heart–the various arrhythmias.  Case, Mandrola, and Zinn are in a unique position to bring this topic to life because each has dealt personally with some form of arrhythmia.  And as long time cyclists (and perhaps with some triathlon experience as well), they’re able fashion the discussion to the avid endurance athlete.  From the medical perspective, the field of arrhythmias is rather complicated, both in terms of the underlying mechanisms of disease and the evaluation and treatment of affected patients, but here the authors have found a writing style that is captivating and accessible to the non-medical reader, while retaining much medical detail that will be of interest.  I give them credit because this is hard to do!

I love the title.  With an arrhythmia, the heart is truly “haywire.”  Ignore the line on the cover, though, about “How too much exercise can kill you.”  That’s unlikely to happen and there’s little in the book about that particular issue.  Instead, focus on “what you can do to protect your heart.”  That’s where the value lies here.

The book is organized into 9 chapters.  In Chapters 1-3, the authors describe in detail how the normal heart works, outline how the heart adapts over time to endurance exercise, and introduce the medical aspects of heart attack and arrhythmias, especially for the endurance athlete.  These sections are well-illustrated and are a great primer for any athlete interested in learning more about the heart.

Chapters 4-6 focus on the evidence of a link between long-time endurance exercise and arrhythmias, what to look for in yourself, and what it’s like to receive the diagnosis of an arrhythmia.  Here, the authors speak from personal experience and their observations and advice are valuable.

Chapter 7 deals with the issue of exercise addiction.  We know that exercise is generally healthy, but most of the benefits of exercise accrue with the first few hours per week.  Why, then, do athletes exercise more?  When does one become addicted?  What are the implications?  This is an interesting and pertinent discussion and might provoke some warranted introspection.

Chapter 8 covers the various treatment options for athletes with various arrhythmia problems.  For athletes who don’t have trouble with arrhythmias, the discussion is educational in a broad sense.  For those who do have arrhthymias, though, there is ample detail here to become educated and be better engaged with your doctor(s) as you sort out the best treatment for you.

Finally, in Chapter 9, the authors wrap up with their “takeaway” on how we might prevent arrhythmia problems.

One of my favorite aspects of the book is the inclusion of Case Studies sprinkled throughout the text, where the authors illustrate their points in a side bar with the personal account of an athlete.  These stories bring us the human side of arrhythmias and show how difficult these problems can sometimes be.

This book is for….

  • the athlete with an arrhythmia problem.  There’s a lot of familiar territory here as well as the opportunity to learn more.  An educated patient is the ideal patient.
  • the athlete with simply an interest in the heart.  I can’t think of a better resource to become educated about the workings of the heart, particularly as they relate to the endurance athlete.
  • the athlete (or the athlete’s spouse or parent) who’s afraid of causing harm to the heart through exercise.  Be forewarned and be vigilant.

 

Related Posts:

  1. Heart to Start, by James Beckerman, MD
  2. The Exercise Cure, by Jordan Metzl, MD
  3. Cardiac Athletes, by Lars Andrews

Laurent Vidal and Cardiac Arrest

Vidal

The news last Thursday was startling.  Laurent Vidal, the 30-year-old French triathlete, reportedly suffered a “heart attack” and cardiac arrest during a swim training session.  You may recall that Vidal is the star of the French triathlon team and finished 5th in the London Olympics.  By report, he complained of chest pain and later collapsed in cardiac arrest.  News accounts indicated that he was revived, regaining consciousness, and was transported to the hospital for further care.  Follow-up reporting suggested that therapeutic hypothermia as well as induced coma had been employed in his treatment.  Over the weekend there was very little reporting, though, at least in the English news media, so I don’t have any additional information about his condition to share here.  On Monday came a Tweet from Vidal:  “Hello world.”  I’ll take that as a good sign and wish Laurent and his fiancé, fellow triathlete Andrea Hewitt, all the best during his recovery.

Interestingly, in a report this morning, came some additional information about Vidal’s medical history.  We learned that Vidal had suffered from exertional syncope (blacking out while exercising) on two previous occasions and had undergone a detailed evaluation after the 2nd episode, in 2011.  At that time he was given the diagnosis of neurocardiogenic syncope, a condition that was thought not to be serious.  I’m sure these previous incidents will be given new consideration in light of Vidal’s cardiac arrest episode.

I can tell from the questions I’ve received about this incident that cardiac arrest remains somewhat of a mystery.  Beyond cardiopulmonary resuscitation (CPR), and possibly the use of an automated external defibrillator (AED), most people don’t have much familiarity with the treatment of victims of cardiac arrest.  Non-medical folks might go a lifetime and never witness such an event.  I thought I’d use Vidal’s story as a starting point for a discussion about the treatment of victims of cardiac arrest.

Cardiac Arrest

We use the term “cardiac arrest” when an individual’s heart has stopped beating effectively.  The victim loses consciousness and stops breathing.  When this happens suddenly, without warning, we use the term “sudden cardiac arrest,” or SCA.  The victim of SCA immediately appears lifeless.

Cardiac arrest is a different problem than “heart attack.”  I’ve written a previous blog post on the terminology of cardiac arrest versus heart attack.  In short, a heart attack occurs when there is complete blockage in one of the coronary arteries that brings blood flow and oxygen to the heart muscle.  This condition typically produces chest pain.  Affected patients are evaluated with coronary arteriography and undergo procedures like coronary stent placement or heart bypass surgery as treatments.

Cardiac arrest occurs because there is a sudden change in the normal electrical activity of the heart.  There is a collection of abnormal heart rhythms, called arrhythmias, that can be responsible:  ventricular fibrillation (VF), ventricular tachycardia (VT), asystole, or pulseless electrical activity (PEA).  With each of these arrhythmias, the heart does not beat effectively and therefore does not pump any appreciable amount of blood.  The blood pressure falls to zero and a pulse can no longer be felt.

Without treatment, the victim of SCA has died.  The American Heart Association (AHA) suggests a conceptual framework called the “Chain of Survival” to outline the necessary links to increase the odds for survival:

  1. Immediate recognition of cardiac arrest and activation of the emergency response system
  2. Early CPR with emphasis on chest compressions
  3. Rapid defibrillation, if needed
  4. Effective advanced life support
  5. Integrated post-cardiac arrest care.

Initial Treatment

If a victim of cardiac arrest is to become a survivor, there must be prompt and appropriate care at each step along the Chain of Survival.

It is important for bystanders to recognize the victim of cardiac arrest–unconscious, not breathing, no pulse.  The initial treatment is CPR.  In the United States, the AHA and American Red Cross offer classes in CPR.  For people who are not healthcare workers, the AHA teaches chest compression-only CPR, instructing the rescuer to do chest compressions centered over the breastbone, or sternum, at a rate of 100 compressions per minute.  The AHA teaches that the 100 compressions per minute rhythm can be maintained by doing the compressions to the beat of the 1983 Bee Gee’s hit song, “Staying Alive.”  Healthcare workers are taught how to do rescue breathing interspersed between sets of chest compressions, either in 1- or 2-rescuer scenarios.  If no nearby bystanders are trained in rescue breathing, then chest compressions alone are appropriate as an initial treatment.

While CPR is being performed, bystander rescuers need to notify the emergency medical system (EMS) to summon more advanced care for the victim.  In the United States, bystanders can call 9-1-1 to alert the appropriate authorities.  The telephone dispatcher will arrange for emergency medical technicians (EMTs) or paramedics to be dispatched to the scene.  The dispatcher can also remain on the telephone to help provide guidance to the bystanders who are tending to the victim.

If there is an AED nearby, somebody should fetch it.   These devices are often located in public spaces such as schools, shopping centers, fitness centers, etc.  They may also be on hand for special events.  The use of the AED is often taught in conjuction with the basic CPR course.  Even without instruction, the AED is designed to “talk you through” how to use the device in an emergency situation.  The AED is opened and the ON/OFF switch is turned ON.  An electronic voice will provide instructions to attach defibrillator pads to the victim’s chest in 2 locations.  The AED will analyze the victim’s heart rhythm and determine if a defibrillation shock would be helpful.  Such a shock is helpful if the rhythm is VF or VT, but is not helpful if the rhythm is asystole or PEA.  If needed, the AED will ask the rescuers to stand clear and it will deliver an appropriate shock, asking you to resume CPR if the shock does not terminate the arrhythmia.  If the shock is successful, the AED will instruct the rescuers to just monitor the patient.  If no shock is needed, the AED will instruct to continue CPR.  The AED will continue to monitor the heart rhythm and work through this same algorithm repeatedly at several-minute intervals until EMS personnel arrive on the scene.

I mentioned at the outset that the survival rate for out-of-hospital cardiac arrest was poor.  It’s encouraging, though, that in localities or situations where CPR training is widespread, the survival rate can be much higher.  Interestingly, in a recent review of SCA at long-distance running events, the survival rate was reported at 29% and was attributed in large part to prompt CPR provided by bystanders.

Advanced Life Support

The next phase of care might best be called advanced cardiac life support (ACLS).  This care is generally begun by EMTs or paramedics who were dispatched to the scene where a cardiac arrest victim is already receiving CPR by bystanders.  Information about the circumstances leading to the victim’s collapse should be passed along to the medical professionals who respond.  Sometimes there are very helpful details.

Away from the hospital setting, advanced life support is usually provided by EMTs or paramedics who have specialized training in this area.  In the hospital setting, many employees–nurses, physicians, and others–can take classes offered by the AHA to become certified in ACLS.  As a result, there may well be ACLS-trained bystanders when somebody suffers cardiac arrest.

Advanced life support will include both chest compressions as well as rescue breathing.  Supplemental oxygen will be provided and breaths will be administered initially using a bag-valve mask.  If the victim is not immediately revived, an oral or nasotracheal tube may be placed into the trachea (the windpipe) to continue to administer breaths to the victim.  Electrode patches will be placed on the victim’s skin and an EKG monitor will be used to determine the heart rhythm.  With CPR and rescue breathing in progress, the advanced cardiac life support phase of care is governed by algorithms that are specific to the exact type of heart rhythm.  There are 2 primary algorithms–1 for VF/pulseless VT and another for asystole/PEA.  In the hospital setting, we actually have hand-held cards with the algorithms to help guide a team of rescuers.

Included in the algorithms will be the use of medications, if needed, as well as defibrillation, if needed, depending upon the particular heart rhythm.  CPR, rescue breathing, and the resuscitation algorithm is pursued while the victim is transported to the hospital. 

Hospital Care

Efforts at resuscitation continue until either the victim’s normal heart rhythm is restored or the team of caregivers concludes that further efforts will be fruitless.  There is no absolute convention about how long resuscitative efforts should be continued, but there are certainly examples of patients who are successfully resuscitated after prolonged CPR.  As just one example, I’ve written here at the blog about the soccer player, Fabrice Muamba, who was revived after 78 minutes of CPR.

If a victim’s heart rhythm is restored, then there are 2 major immediate goals:  1) prevent a recurrence of the near-fatal arrhythmia and 2) protect the body’s organs, as much as possible, from the effects of the disturbed circulation while the resuscitation efforts were being made.  Efforts at the first goal will depend upon the known, or suspected, cause.  Evaluation and monitoring is conducted to be certain that the blood oxygen levels and blood electrolyte levels are appropriate.  Often, anti-arrhythmic medications will be used for this purpose.  The second goal is also very important.  We know that, even with CPR that is successful and results in revival of the patient, there can be insufficient blood supply to the body’s organs for a period of time.  The brain is particularly susceptible to injury because of inadequate blood floow or oxygen, even for relatively short periods of time.  One technique that has gained popularity in recent years is the use of induced coma combined with hypothermia (lowering the body temperature by several degrees) to reduce the metabolic demands on the brain for a period of about 48 hours.  This allows potentially better recovery of the brain.  We know that such an approach may improve the neurologic outcomes for at least some patients who have suffered cardiac arrest.  This technique appears to have been used in the case of Laurent Vidal.

The last issue is to determine what caused the cardiac arrest.  There’s actually a fairly long list of possible causes.  In the sports setting, for younger athletes the most likely heart-related causes are hypertrophic cardiomyopathy (HCM)–an inherited disorder of the heart muscle; a coronary artery anomaly–an artery that developed abnormally during development; an inherited cardiac ion channel abnormality (eg, long QT syndrome); or arrhythmogenic right ventricular cardiomyopathy (ARVC)–another inherited disorder of the heart muscle.  But sometimes cardiac arrest may be have a non-cardiac cause like pulmonary embolism or stroke.  Even a sharp blow to the chest can produce cardiac arrest, a situation called “comotio cordis.”  The evaluation of survivors of cardiac arrest is done in a systematic way to sort through the various possibilities.  It’s usually possible to determine a cause, but there’s a small chance that no cause is found.

Related Posts:

1.  Sudden cardiac arrest in NCAA student athletes

2.  Dana Vollmer and ICD

3.  Athletes, Sudden Death, and CPR

Coach John Fox and Aortic Valve Replacement

 

NFL Broncos head coach, John Fox, will reportedly undergo aortic valve replacement (AVR) this week.  I’ve gotten some inquiries over the weekend about his situation and I thought I’d take a few minutes to write about aortic valve problems and aortic valve replacement.

This story is reminiscent of Atlanta Falcons coach, Dan Reeves, who had urgent coronary artery bypass surgery in 1998, late in his team’s 14-2 season.  For reference, Reeves made an excellent recovery, rejoined the team just 3 weeks after surgery, and went on to coach for another 5 seasons.

Aortic Valve Disease

The aortic valve is the valve that lets blood out of the heart.  The left ventricle of the heart pumps blood out through this valve into the aorta with each heart beat.  At rest, this might amount to about 5 liters per minute.  The valve ordinarily has 3 tissue thin leaflets, but some individuals are born with just 2, a condition known as bicuspid aortic valve (BAV).

There are 2 different problems with the aortic valve.  The valve can become narrowed or it can leak.  Either situation produces trouble for the heart, which then must do extra work.  When the valve is narrowed, we call the condition aortic stenosis.  When the valve leaks, we call the condition aortic regurgitation.  When there is severe aortic stenosis or regurgitation, aortic valve replacement is often the only available curative treatment.

In this country the most common cause of aortic stenosis in adult patients, by far, is build-up of calcium in the valve leaflets over many years’ time.  This progressive calcification causes the valve leaflets to become thickened.  As a result, they don’t open or close easily and eventually they become immobile.  Severe aortic stenosis most often manifests in patients 60+ years old.  In individuals with BAV, this process occurs much earlier in life, and the condition often manifests in patients in their 40’s and 50’s.  Rheumatic fever is probably the next most common cause.  The normal aortic valve opening is about the size of a half dollar.  But with severe aortic stenosis, the opening can be reduced to the size of a drinking straw.

Aortic regurgitation may occur for a variety of reasons such as:  infection (that we call endocarditis) that destroys the valve leaflets; enlargement of the aorta that stretches the leaflets apart; rheumatic fever; or trauma.

Patients with severe aortic stenosis have symptoms of shortness of breath with exertion, chest pain/discomfort, or light-headedness or blacking out (that we call syncope).  Patients with aortic regurgitation most often have symptoms of shortness of breath with exertion.  Either condition can be revealed by listening to the heart with a stethoscope because either condition produces turbulent blood flow that can be heard as a heart murmur.  The diagnosis is confirmed using ultrasound, in a test known as an echocardiogram.

Once there are symptoms, patients with severe aortic stenosis need operation.  Once the heart function suffers because of aortic regurgitation, operation is needed.  In either case, we usually plan for operation at the earliest, convenient opportunity.  Emergency operations for aortic valve problems are unusual.

In John Fox’s case, we know from reporting that he was in Charlotte, North Carolina to visit his doctor(s) about a known aortic valve problem–one that was being monitored and for which aortic valve replacement was being planned once this year’s football season was complete.  The initial news reports spoke about the possibility of a heart attack, but he apparently became light-headed while playing golf.  It’s not clear if he passed out completely.  He was taken to the hospital where additional testing was completed.  The Broncos then made the announcement that Fox would undergo surgery this coming week.

Aortic Valve Surgery

Aortic valve replacement is a very common heart operation today.  And while there are new technologies that allow for valve replacement in high-risk patients without conventional operation, the vast majority of patients undergo typical open heart surgery to replace the valve.

The patient has general anesthesia with use of a breathing tube to provide ventilation while asleep.  Access to the heart is gained by dividing all or part of the sternum and using a retractor to spread the rib cage open.  The first main part of the operation involves connecting the patient to a heart-lung bypass machine that sits at the side of the operating table and takes over the job of the patient’s own heart and lungs for a period of time.  This allows the patient’s heart to be still and empty of blood.

The next main part involves replacing the valve.  An opening is made in the aorta, the large blood vessel that carries blood away from the heart.  This allows the surgeon to look in and see the diseased valve.  In the most straightforward operation, the patient’s aortic valve is removed using scissors and any calcium-related debris is also removed.  A measuring tool is used to determine the correct size for a substitute valve which is then taken from the shelf.  Sutures are used to sew the substitute valve into the opening left behind where the patient’s valve was removed.  The opening in the aorta is then closed with sutures.

The last major part of the operation involves letting the patient’s own heart and lungs take back over again, and gradually reducing the amount of help that the heart-lung machine provides.  Once the patient’s heart is beating again, the sternum is re-approximated with wires and the overlying tissues and skin are re-approximated using sutures.  The entire operation usually takes about 3 hours.

There are several options for substitute valves.  Mechanical valves are made out of space-age materials and are designed to last forever, but patients must take blood thinning medications to prevent blood clots from forming on the prosthetic valve.  Tissue valves (eg, aortic valve “borrowed” from a pig) don’t require anticoagulants, but the valves don’t last forever.  The modern tissue valves can be expected to last 10-15 years in adult patients and then some will deteriorate; re-replacement of the valve may sometimes be needed.  In special circumstances, other more exotic options may be appropriate, but we won’t consider those options today.

Recovery from Operation

The typical patient wakes up soon after the operation.  The breathing tube and ventilator are withdrawn once the patient is wide awake and breathing on his/her own.  Most patients will spend a night in the intensive care unit and then several more days recovering in a regular hospital room.  A typical stay would be about 5-7 days.  We work hard to have patients up and walking on the first day after operation and most are walking laps around our hospital ward by the time they go home.

Many patients with AVR notice even in just the first couple days after operation that they no longer have the symptoms that led to discovery of their problem.  Particularly for aortic stenosis, the calcification of the valve happens so gradually that patient’s aren’t always aware of how much of a decrement there’s been in their exercise tolerance.

As the sternum heals, we ask that patients avoid physical activities that place stress on the sternum and shoulders (eg, pushing, pulling, reaching, etc.) for 1 month after the operation.  The sternum regains about 75% of its strength in about 1 month.  In my practice we also restrict driving for that same month.  Most any other activity is allowed and we encourage lots of walking as the preferred type of exercise.

Each patient’s situation with return-to-work is different, not only because each patient’s recovery is different but also because each patient’s job situation is different.  In Fox’s case, if all goes well, I wouldn’t be surprised to see him back at work, at least in some capacity, very quickly.

Best wishes to John Fox!

More on Athletes and Bicuspid Aortic Valve (BAV)

 

I probably get more inquiries from athletes with bicuspid aortic valve (BAV) than any other single heart problem.  Maybe that’s not surprising, given that I’m a heart surgeon and that many individuals with BAV need operation at some point.  Nonetheless, I think there’s considerable confusion about this condition, in terms of diagnosis, implications for the athlete, and its treatment.

I first wrote about BAV in a short post here at the blog back in 2009.  That post is a starting point for today’s discussion.

To quickly review, individuals with BAV have an aortic valve with 2 unequal–instead of the usual 3 equal sized–leaflets.  As a consequence, these individuals develop earlier calcification of the valve leaflets, leading to narrowing, or stenosis.  They are also predisposed to enlargement of the ascending aorta, the large blood vessel that carries blood flow away from the heart.  This can lead to stretching apart of the valve leaflets and leakage at the valve, known as regurgitation.

Looking through the reader comments here at the blog and reflecting on the athlete inquiries I’ve received, I thought I’d cover some of the major issues.

First, you’re not alone!

BAV is one of the most common congenital heart conditions, occurring in about 2% of individuals.  In large-scale pre-participation cardiac screening programs for young, competitive athletes, BAV is one of the most commonly identified abnormalities.

Historically, a heart murmur was the most common reason affected individuals were identified.  Today, echocardiography (ultrasound) for screening or diagnostic purposes for some other heart problem is the most common way that BAV is detected.

Finally, athletes are not spared.  Several contemporary elite triathletes have BAV and I’ve written about their stories in:

Examples from other sports would include Arnold Schwarzenegger, among others.

And of course the problem occurs in everyday, recreational athletes, too.  Check out Anthony DiLemme’s blog, Anthony’s Heart Valve Replacement Saga.  He’s a 30-year-old 8th grade science teacher, a cyclist and outdoorsman, who is chronicling his story with BAV–from diagnosis, to evaluation, to preparations for upcoming valve replacement surgery.  His story is typical.

On the bright side, there is ample evidence that, in the modern era, life-expectancy is not shortened for individuals with BAV compared to the general population.  That’s important to keep in mind.

Before operation is needed

It’s worth knowing if you have BAV.

Aside from the problems with aortic valve stenosis or regurgitation or with enlargement of the aorta, individuals with BAV can also suddenly develop the problem of aortic dissection.  With aortic dissection, the aorta can develop a tear on its inside wall, leading to unraveling of its layers, and even rupture.  This is thought to occur at a rate of about 0.1% per year in adults.  This can be a life-threatening problem and is more apt to occur with progressive enlargement of the aorta and with uncontrolled high blood pressure.

The American College of Cardiology (ACC) in conjunction with the  American Heart Association (AHA) has issued guidelines for the evaluation, monitoring, and treatment of individuals with BAV:

  • Patients with known BAV should undergo:
    • An echocardiogram to evaluate the aortic valve for stenosis or regurgitation and to assess for any other structural heart problems
    • A chest CT scan to make measurements of the diameter of the aorta at various points along its length.
  • Cardiac CT scan or magnetic resonance imaging (MRI) are alternatives if echocardiography is not available or possible for some reason
  • If there is enlargement of the beginning portion of the aorta to greater than 4.0 cm, the individual should have a yearly assessment of the diameter of the aorta
  • Medical therapy may be useful to slow or halt the progression of aortic valve disease and aortic enlargement by reducing the blood pressure and the blood pressure across the aortic valve.  Beta-blockers (eg, metoprolol) are recommended for this purpose.
  • Because BAV may be an inherited condition, first-degree relatives of individuals with BAV should undergo evaluation.

In my opinion, these are useful guidelines for athletes and non-athletes, alike.  The guidelines do not address the frequency of surveillance for individuals with BAV and no enlargement of the aorta.  For these individuals, provided there is no other relevant heart disease, it may be appropriate to have follow-up echocardiogram and/or CT scanning every 2 years.

The data regarding the progression of disease in athlete patients with BAV are limited.  Guidelines specifically for athletes come from the Proceedings of the 36th Bethesda Conference in 2005.  Parenthetically, it may be time for an update.  The guidelines were developed by an expert panel based on the scientific information available at that time:

  • Athletes with BAV, no significant valve stenosis or regurgitation, and an aortic diameter less than 4.0 cm can participate fully in their sport(s)
  • Athletes with BAV and enlargement of the aorta to between 4.0 and 4.5 cm can participate safely in only low and moderate intensity sports (this would exclude the typical endurance sports of swimming, cycling, running, triathlon, etc.)
  • Athletes with BAV and enlargement of the aorta to greater than 4.5 cm can participate safely only in low intensity sports (eg, golf, bowling, billiards).

The issue has not been studied very well, but one recent study suggests that continued participation in sports for periods of up to 5 years does not change the natural history and progression of BAV.  Instead, even with continued sports participation, the progression of both valvular and aortic disease is no different from that in the general population.

Who needs operation?

Operation is needed if there is severe aortic valve stenosis, severe valve regurgitation, or significant enlargement of the aorta.  Again, there are ACC/AHA guidelines for when operation is needed:

  • Aortic valve replacement is recommended for nearly all patients with severe valve stenosis (valve opening less than 1.0 cm2)
  • Aortic valve replacement is recommended for patients with severe valve regurgitation if there are symptoms due to the regurgitation (eg, shortness of breath with exertion) or evidence that the heart is suffering because of the regurgitation (enlargement of the left ventricle)
  • Repair or replacement of the beginning portion of the aorta is recommended if there is enlargement of the aorta to greater than 5.0 cm or if the rate of increase in the aortic diameter exceeds 0.5 cm per year

Sometimes more than one indication for operation may be present, so there is the additional guideline for patients who need operation for aortic stenosis or regurgitation:

  • In patients needing valve replacement because of stenosis or regurgitation, the aorta should be repaired or replaced if the aortic diameter exceeds 4.5 cm.

I know from discussion with athletes over the past few years that there are differences of opinion among cardiologists and heart surgeons about these guidelines.  These differences of opinion may be legitimate.  Consensus guidelines are developed to be broadly applicable, but the guidelines may not be applicable in a given athlete patient’s circumstance.  There are a multitude of patient-specific circumstances that must be considered when deciding if and when operation is needed.  Only your cardiologist and heart surgeon will be in a position to make those considerations.

In practice, the indications for aortic valve replacement for severe aortic stenosis or severe aortic regurgitation are straightforward and uncontroversial.  It’s also clear-cut that patients with significant enlargement of the aorta to greater than 5.0 cm need operation for replacement of the aorta.

One situation that seems particularly ripe for differences of opinion is that of the athlete with BAV, no significant stenosis or regurgitation, but with an aortic diameter of 4.5 to 5.0 cm.  This is an unfortunate situation for the athlete patient because the consensus guidelines do not yet recommend operation, yet advise against strenuous sports activities.  My personal approach to endurance athletes in this situation would be to offer operation if the patient wanted to continue to participate in endurance sports (after operation) and was willing to assume the risks of operation.  But I recognize that not all cardiologists or heart surgeons would agree.

Options for operation

Substitute valves.  There are 2 broad categories of heart valve substitutes that can be used to replace the human aortic valve:  mechanical valves or bioprosthetic (“tissue”) valves.

  • Mechanical valve.  These valves are constructed from high-tech materials that are designed to last essentially forever.  Unfortunately, these materials may cause tiny blood clots to form on their surface and, for that reason, patients must take blood-thinning medications (eg, warfarin) forever to prevent this complication.  The major brands include St. Jude Medical, Medtronic, Sorin-Carbomedics, and On-X.
  • Bioprosthetic valve.  This type of valve is made primarily from animal tissues.  One example is the aortic valve “borrowed” from a pig.  Another example is a valve that is made from “fabric” borrowed from the pericardium of the cow.  These valves have the advantage that blood clots are much less likely to form on their surface, so patients do not need to take blood-thinning medications (other than, perhaps, aspirin) in the long term.  They have the disadvantage that they do not last forever.  Young patients who receive these valves may need to have the valve re-replaced because it “wears out” at some point.  The major manufacturers include Medtronic, St. Jude Medical, and Edwards Lifesciences.

Aortic replacement.  When the aorta is enlarged in the setting of BAV, there are a couple possibilities:  the valve needs to be replaced–or it doesn’t:

  • With valve replacement.  When the aorta needs to be replaced along with the aortic valve, we call this procedure an aortic root replacement.  This is a complicated operation technically and must be tailored very carefully to the patient’s specific situation.  Options include:
    • Mechanical valve conduit.  Products are available that combine a mechanical valve attached to a Dacron fabric tube.  This is used, as a unit, to replace the patient’s aortic valve and beginning portion of the aorta.  The coronary arteries are re-implanted into the Dacron tube.  Of the options listed here for aortic root replacement, this is by far the most common.
    • Bioprosthetic valve conduit.  This is not commercially available, but can be assembled in the operating room.  The operation is like described above for the mechanical valve conduit.
    • Medtronic Freestyle valve.  This is a unique product that is a porcine aortic root that can be used to replace the human patient’s aortic root, like the other operations above.
    • Ross procedure.  This is the most technically complicated option.  The patient’s aortic valve and beginning portion of the aorta are removed.  The patient’s own pulmonary valve is removed and then used to replace the aortic valve and beginning portion of the aorta.  The coronary arteries are re-implanted into the pulmonary valve trunk.  A cryopreserved pulmonary allograft (the pulmonary valve and trunk from a human cadaver) is then used to replace the patient’s pulmonary artery.
  • Without valve replacement.  When only the aorta must be replaced, a Dacron fabric tube is used.

Valve repair.  There is recent interest and experience with aortic valve repair–instead of replacement–for patients with BAV.  These techniques are most applicable to situations in which there is regurgitation, rather than stenosis, of the valve and when there is also enlargement of the aorta.  To help correct the regurgitation, the cusps of the patient’s valve leaflets can be tailored, with the valve leaflets left in place.  Then, a Dacron fabric tube can be used to reconstruct the aorta, in a so-called valve-sparing aortic root replacement.  This procedure has the particular benefit that no artificial valve (with the disadvantages described above) needs to be used.  The potential downside relates to durability.  Questions currently remain about how long such repairs will last and whether patients might require re-operation at some point in the future.  This valve repair option is one that might best be pursued at a center that specializes in this problem.

After operation

The recovery from heart surgery can be hard to predict for any given patient, but we know that young otherwise healthy patients tend to do well.  Most patients spend about a week in the hospital after operation and then are able to go home.

Early after operation, and for perhaps the first month, we typically limit activities that place stress on the shoulders and sternum.  This gives a chance for the sternum, which was split during the operation, to heal completely.  So for that first month, we usually advise no driving, lifting, pulling, pushing, reaching, etc.  During that first month we recommend ample walking as the best form of exercise.  After the first month, patients are generally allowed to return gradually to all of their previous activities.

Patients who’ve had aortic valve replacement and/or replacement of the aorta will require life-long monitoring by their doctor, with periodic echocardiogram and/or chest CT scanning.  Over time, there will be some patients who develop problems with the prosthetic heart valve or enlargement of some portion of the aorta (that hasn’t already been replaced) that requires operation.

Athletes will ask when they can return to their sports.  Consensus guidelines from the Proceedings of the 36th Bethesda Conference recommend:

  • Athletes with mechanical or bioprosthetic heart valves may participate in low and moderate intensity sports
  • Athletes who are taking blood-thinning medications should avoid sports where bodily injury, with potentially life-threatening bleeding, might occur

The first recommendation does not include the endurance sports.  The truth is that there is not much scientific information about what happens to such athletes if they do return to endurance sports.  At issue are the potential long-term effects of repeated episodes of high heart rate and high blood pressure that accompany intense exercise.  Unanswered questions include:  Can a bioprosthetic valve wear out more quickly than expected?  Does the (unreplaced) aorta enlarge over time?  If so, how quickly?  Do medications like beta-blockers limit any potential harm?  We just don’t know.

Yet I’m personally aware of a good number of athletes who’ve returned to endurance sport after operations of various sorts for BAV, presumably after discussion with their doctors.  Athletes should have detailed discussion with their doctors about any prudent limitations to exercise after operation and settle on a mutually agreeable plan.

Related posts:
1.  Aortic stenosis and bicuspid aortic valve (BAV)
2.  Elite triathletes and heart problems
3.  Index to blog posts and online articles

George W. Bush Gets a Stent

 

We learned from news reports earlier this month that former President George W. Bush was treated with a coronary stent for a blockage in a coronary artery that was discovered during his annual medical check-up.  Of course, a great many Americans are treated each day for coronary artery disease (CAD), but Bush’s case draws my attention not only because he’s the former President but also because he’s known to be physically active, especially with cycling.


Bush’s Medical History

The fine details of Bush’s most recent health matters haven’t been made public, and might never be.  But we know that while President from 2001 to 2009 he enjoyed comprehensive medical check-ups performed at the Bethesda Naval Medical Center.  Each year, short statements were issued by the White House that summarized the President’s health.  We can take a look back at some of that reporting.

Before taking office, the President received annual medical check-ups from Dr. Kenneth Cooper at the Cooper Clinic in Dallas, Texas.  We know that, at the time he took office in 2009, he had no heart problems and no significant family history of heart disease.  He occasionally smoked a cigar, did not drink alcohol, and had typical caffeine intake in the form of diet soft drinks and coffee.

From his examination at age 58 in 2004, we know that:  he was 6 feet tall, weighing 200 pounds; his body fat was 18.25%; his resting heart rate was 52 and the blood pressure was 110/60; and the total serum cholesterol level was 170 mg/dL, with a decrease in the LDL (bad cholesterol) and increase in the HDL (good cholesterol) from one year previously.  He was noted to have mild calcification of the coronary arteries (presumably based on a screening cardiac CT scan) and both aspirin and a cholesterol-lowering agent were prescribed.  At the time, he was running 7 1/2 minute miles on the treadmill and was cycling several times per week.

In 2005 we learned that the President’s weight had decreased by a few pounds and the blood pressure and resting heart rate remained low.  He underwent an exercise treadmill test that was normal and his doctors concluded that he was at “very low risk of coronary artery disease.”  By 2005 Bush had given up running because of difficulties with knee pain, but continued to be active with cycling and weightlifting.

In 2006 at age 60 he was noted to have an EKG without worrisome abnormalities and a normal stress echocardiogram.  Doppler ultrasound studies of the arterial blood supply to the legs was normal and a screening ultrasound of the abdomen showed no evidence of abdominal aortic aneurysm.  Laboratory values included:  total cholesterol 174 mg/dL, HDL 60 mg/dL, LDL 101 mg/dL, triglycerides 61 mg/dL, and normal values for C-reactive protein (CRP) and homocysteine.  Interestingly, it was reported that he was taking no prescription medications despite the 2004 statement about the recommendation for a cholesterol-lowering agent.  On the basis of the available information, the President was thought to have “low” to “very low” coronary artery disease risk.

The Coronary Stent

As we all know, Bush left office in 2009.  Since then, his medical affairs have been private.  So, fast forward to 2013….

We know that Bush went recently for his annual medical check-up at the Cooper Clinic and the following day at Texas Health Presbyterian Hospital was treated with a coronary stent for a blockage in a coronary artery that had been discovered duringn his evaluation.  The details have not been made public, but it’s probably fair to assume that he underwent a stress test that was abnormal and that coronary arteriography was organized for the following day, with implantation of the coronary stent at the same setting.

The fact that Bush was treated with a stent for the coronary artery blockage has created a bit of a stir in the medical community.  For those who are interested you can read more at:

“Did George W. Bush really need a stent?,” an article by Larry Huston in Forbes.

“The George W. Bush stent case:  An incredible teaching opportunity on the basics of heart disease,” a blog piece by Dr. John Mandrola.

“Heart stents still overused, experts say,” an article by Anahad O’Connor at NY Times Well.

Basically, the controversy revolves around the appropriate treatment for asymptomatic patients–those without chest pain, heart attack, etc.–or those with so-called “stable” symptoms–for instance, chest pain with exertion–who are found to have blockage(s) in the coronary arteries.  In truth, there has been no public reporting on whether or not Bush had any such symptoms, either with exertion or at rest.  And there has been no updated reporting on Bush’s physical activity level or other relevant risk factors for CAD.  But information from the best scientific studies suggests that asymptomatic patients and those with “stable” CAD fare no better, with respect to heart attack, stroke, or death, with a stent than without, so long as the best possible medical therapy is provided.

At any rate, this controversy will be one for our community of heart professionals to discuss and sort out.

What Can We Learn?

From the athlete’s perspective, though, Bush’s story reminds us of the importance of coronary artery disease as we age, even if we remain physically active.  A few thoughts….

1.  The discovery of CAD is almost always a surprise….particularly for an athlete.  Nobody is immune from this disease, even if remaining physically active helps guard against it.

2.  There is a set of well-established risk factors for CAD.  I’ve talked about this issue previously here at the blog.  Let’s remember that there are some risk factors that, unfortunately, can’t be modified:  increasing age, being male, and having a family history of early CAD.  Other risk factors are under our control:  obesity, high blood pressure, smoking, abnormal serum cholesterol and lipid levels, diabetes, and physical inactivity.  Adult athletes should know where they stand with respect to these risk factors and work to improve any that can be modified favorably.  An ongoing relationship with a healthcare provider will offer the necessary framework for this.  Periodic measurement of the blood pressure and testing of the serum cholesterol/lipid levels every 5 years are recommended.

3.  Our personal situation with CAD will likely change over time.  The process in which plaque builds up in the coronary arteries can begin early in our lives.  But this process is often progressive as we age.  That’s why we say that increasing age is a risk factor.  Bush’s story illustrates just how this can happen.  In 2004-2006 he had very favorable clinical and laboratory data regarding his risk of CAD, including a normal stress echocardiogram in 2006.  Yet today we know that an important blockage had formed, or more likely progressed, in the interim.  It’s important, then, to periodically re-visit our circumstance with CAD.

4.  Warning signs are important.  Important blockages in the coronary arteries often lead to symptoms of angina–chest pain/discomfort or perhaps difficulties with breathing.  When angina occurs with exertion, we call it exertional or stable angina.  When angina occurs at rest, we call it unstable or rest angina.  Either form of angina should prompt timely evaluation.  That evaluation may take the form of stress testing or coronary arteriography to look for blockages in the coronary arteries.  Unfortunately, there are some patients whose first sign of trouble is a heart attack, or myocardial infarction.  This can occur in athletes and non-athletes, alike.

Related Posts:
1.  Coronary Artery Disease:  The Essentials
2.  Two Stories, Two Endings, a blog post about endurance athletes and CAD.
3.  In the News:  Coronary Plaque Build-up in Marathoners