HCM Summit notes part 4

Part 4

 

Debate:  What is the most effective strategy for preparticipation screening to detect cardiovascular abnormalities in trained athletes?

Counterpoint:  The U.S. Perspective

Barry J. Maron, MD

 

 The Italian model is not appropriate for the US.  Obstacles include a huge number of US athletes, low/infrequent and number of persons with abnormalities, incomplete reporting of events.  The US has an informal system emphasizing guidelines for physical examinations.  Other differences involve who examines the athlete (MD/non-MD in US; sports medicine specialist MD in Italy) and key differences in government and legal systems between the two countries.

Is a mandatory US screening program for EKGs appropriate?   No.  Maron says not a good idea in our system.  It comes down to policy issues, not emotional.  It would impact 15 million people a year to find a needle in a haystack.  There are only about 75 incidents a year.  EKG screening would only identify 50 people and many conditions would be missed..  USA does engage in some screening protocols.  The country is too large,  It is not practical, there is potential for liability to the screener.  In Italy ARVD causes most sudden death while in USA, its HCM.   Physicians would become enforcers and would be the “bad guys’ keeping the kids from sports.  Who is qualified to do it? There are only about 1500 pediatric cardios in the U.S.                          

            Is mandatory screening something that can work in the US – with healthcare reform or without.  – NO.  The US does screen its athletes and it is required as customary practice but not by federal law. States have the right to set laws governing this issues but must also provide funding for mandates. Thus it will likely never come to pass that ECG's will be a required part of screenings in the USA, instead history and the AHA guidelines will likely remain the standard for screening at this time.

 

 

 Take Home Message: 

The Italian model is not appropriate for the US a comparison of US sudden cardiac death in athletes (size comparable to Italy - MN to Ventno region of Italy) shows US results similar to Italy after use of screening.  The US does screen its athletes and it is required as customary practice, routine ECG’s are not consistent with the current or future US Healthcare system.  Individual and local screening efforts are encouraged.                 

 Key points: 

Many obstacles preclude use of the Italian screening model in the USA but individual local screening efforts are encouraged.

 

The spectrum of pharmacologic treatment

Mark V. Sherrid, MD

 

 Obstruction due to systolic anterior motion of the mitral valve (SAM) is often a complication of HCM and increases risk of stroke.  Most HCM patients respond to pharmacologic therapy.  Ideally obstruction can be treated with drugs, decreasing or lessening obstruction, and negating or delaying need for surgery (myectomy) or ablation.  Issues include what drugs to use, how do they work, how well do they work, and in what order should drugs be used and/or combined.  Verapamil, beta blockers may help non-obstructive HCM.  Disopyramide plus beta blockers reduce exercise related rise in gradient.  All have side effects.  Studies are examining issues in combination with echos.  There are drugs to be avoided in HCM, especially nitrates.

Verapamil is the first-line treatment for non-obstructed patients.  It does not improve diastolic function.  IT is for ischemic chest pain.  It is hard to treat symptomatic non-obstructive patients.  Beta blockers are 2^nd choice. Drag of the mitral leaflet is cause of obstruction.  In mid systole the valve touches the septum.  Extent of obstruction depends on mitral septal contact.        Most patients respond to drugs.  Myectomy and abation are only required by a minority.  We don’t want to use vasodilators.     How do drugs reduce obstruction?  A small decrease in ejection velocity leads to a large decrease in gradient.  Beta Blockers don’t reduce resting gradients.  If patients still have symptoms, verapamil or disopyramide are used.  Sometimes with verapamil vasocilation may increase gradient so there is caution in the use of this drug.  Norpace most effective to reduce gradient.  Side effects can limit.  Side effects can be reduced by lowering dose or time release pyridostignmine if needed.  Mestinon controlled release.  Two thirds  of patients managed with medical therapy.  One half of patients needed surgery.  Improvement in gradient and quality of life improved with norpace.  About one-third needed surgery.  Nonrpace and Beta Blockers together lowered gradients from 73 – 27 on the average with imrprovement in symptoms and NYHA Class.  Beta blockers improve symptoms and patients should start with beta blockers for several weeks before moving on to other drugs.  Verapamil causes constipation.  Stool softeners are indicated.  Long term gradients over time have bad consequences and should be approached earlier so earlier intervention may be necessary.                                                                       

Linda:  Hoping for fibrotardie behavior in future.  Verapamil still best for non-obstructed, symptomatic patients.   Beta blocker – prevents exercise related obstruction, won’t reduce resting gradient.   Verapamil best for non-obstructed symptomatic patients – improvesi schemia.   Disopyramide & Beta blocker for exercise induced obstruction.           

Take Home Message: 

Medical therapy is often very helpful in HCM, lowering sudden death rates, improving quality of life, and reducing need for more complex treatment.  Adverse effects are rate but all use of drugs in HCM requires ongoing medical review with the extent of surveillance dependent on drugs and patient characteristics.

 Key points: 

Drug use is essential and key to treatment success for people with HCM.

Techniques, indications and results of surgical septal myectomy:  The historic gold standard

Joseph A. Dearani, MD

 

Obstruction increases risk of death as well as significant functional impairment.  Surgery has grown since the early 1970’s for HCM with 150+ myectomies at Mayo annually now.  Excellent results include survival long term equal to the general population and much superior to non-operative patients.  Myectomy is indicated with LVOT obstruction, quality of life limitations (fainting, pain, shortness of breath), and failure of drugs/therapy to reduce symptoms.  Surgery does not leave heart scarring as is true of ablation.  Myectomy can target specific muscle compared to ablation’s variable effects on the septum.

 Obstruction is bad and reduces mortality.  Obstruction increases risk of death, Atrial Fibrillation and sudden death.  It Is associated with increased risk of sudden death related to severity of obstruction.  70% of HCM patients have obstruction.  Mayo averages 150 myectomies/year.  Mortality is now less than 1%.  Symptom response is dramatic.  Class 3 or 4 drop to class 1 or 2.  All symptoms are dramatically reduced..  Post surgical survival is same as regular population.  It is also better than non-obstructed HCM patients without operation.  After obstruction is relieved the heart remodels and LV mass is reduced.  Indications for myectomy are LVOT obstruction, angina, dyspnea, syncope affecting quality of life, and symptoms have to be present after drugs have been implemented.  When the muscle is removed, they go below the scarred area –otherwise it will move the obstruction lower.  Myectomy carves a trough in the outflow tract.    IT is gold standard.  Alcohol ablation leaves septal scar.  Myectomy causes no scar in LVOT and trough is in anterior septum.  Ablation targets only one small area and is more variable distribution.  Complete heart block is slight-- less than half of patients.  After ablation bad arrhythmias can result later.  After myectomy there is a decrease in ICD discharge, in ablations, an increase.        Sometimes fixed subaortic stenosis is mistaken for HOCM.  Must have SAM and if there is-- Aortic Regurgitation.  There is no role for Ablation in this.  Also, if there is papillary muscle issues they can be fixed..                                                                                    If not enough muscle is taken, the patient may need a redo.  Can also be due to mid-ventricular obstruction.  Can also do MAZE procedure with a fib.  Reduces need for anticoagulation.  In pediatric patients, good success, gradients reduced, though not as much as results.  Morbidity is a bit higher and greater possibility of valve problems resulting from surgery.  If you do an ablation first and then go to surgery, it is not a good way to go because mortality is greater, you will likely be pacemaker dependent and arrhythmias are very common.                                                                                                       This operation MUST be done in an experienced center.  The risk of incomplete resection or harming adjacent structures is just too high.          

The original myectomy is NOT what is happening today--it is far more advanced and takes more muscle and works on papillary muscles, mitral valve and more.

ICD discharge rate is lower post myectomy – higher in asa patients

1.    Evaluate

2.    Opt meds

3.    Re opt meds

4.    Surgery offered

5.    Patients who refuse surgery – ablation offered

 

Critical to have center review cases – why

1.    5-10% of pts referred don’t really have HCM – ask if SAM is present or not… check for membranes 

2.    Pap mus abnormalities insert into the leaflets… this has to be reviewed carefully

3.    MV review – MINIMAL work if any should be done to MV – replacement of MV very rare

 

 

Take Home Message: 

Optimize meds, review what happens with drugs, if problems persist consider myectomy—with ablation an alternate for patients with co-existing conditions and other complications increasing risks.  Surgical risks greater for myectomy after ASA.  Myectomy relieves gradient & symptoms in 95%                                                                     

Key points: 

 Obstruction is common in HCM and myectomy effectively relieves it with favorable long-term outcomes.

 

The Toronto surgical myectomy experience:  Determinants of success and prognosis

Anna Woo, MD and E. Douglas Wigle, MD

 

Toronto’s experience with myectomy dates to the 1960’s.  Data exists for 338 patients receiving myectomy from 1978-2002 showing overall survival rates similar to “normals”.  Mortality rates for the surgery of 540+ patients – 1978-2009 – are about 1%.  Data continues to be collected and analyzed for long-term outcomes and prognosis of HCM patients receiving surgery.  Increased age at the time of surgery and atrial fibrillation are compounding factors.

 Long HCM tradition at Toronto General.  They use a TEE during surgery to monitor.  There were some deaths back in the early to mid 90s, but lately there have been almost none, though they had 1 this year from a PE in an elderly woman.  SAA had an almost 3% chance of mortality.

Myectomy remains gold standard for septal reduction (long term relief of LVOTO in HCM)        

Take Home Message: 

Myectomy is safe and effective when done by highly expert surgeons in centers of excellence.

Key points: 

Myectomy should remain the gold standard for the long-term relief of left ventrical obstruction in HCM.

 

Does septal reduction prolong life and is there a case for earlier intervention?

Steve Ommen, MD

 

 Data from registries of patients (historic observation) and case-control studies (analysis of matched groups of patients with similar characteristics and symptoms) have shown benefits in terms of long-term survival, improved functioning, reduced symptoms, and less ICD discharges.  Myectomy data suggests significant benefits of surgery.  However, observational and case studies are less rigorous evidence and referral bias (selection of non-random patients) limit the value of “evidence”.  Future studies may answer questions of the value of surgery in helping permanent “remodeling” of the heart—an effect not found in ablation.  Additional studies may address timing of surgery and possible early intervention/surgery in patients with large gradients but few symptoms.  “Preventative” surgery can be considered but factors require analysis.

Why should septal reduction improve survival?  People with obstruction have higher death rates.  It is possible that the obstruction increases risk of death. So it seems logical that it might improve survival. When looking at historical data, the overall survival 5 years after surgery is 95%.  Patients who had myectomy have after operation survival equal to general population with ½% /year mortality.  Observational data suggests.  Sudden cardiac death survival is more than 95% after myectomy and a lower death rate.  When looking at ICD discharge, there also seems to be a benefit. – it is lower than in other HCM patients without surgery.  This is not a non-randomized trial with referral bias, so data is flawed.  1.5 – 3% death rate for Ablation.  5%/year discharge rate for ICD after alcohol ablation.  Another study last year was slightly lower.  But over a 15 year period, the risk is much higher of appropriate ICD discharge.  Surgical septal reduction can extend life, but not alcohol ablation.  Is there a case for earlier intervention?  It might prevent irreversible, long-term complications and procedural complications rates are lower in healthier patients.  The risk of the procedure has to be less than the procedure, and we need to pick people who are on the road to getting worse.  If patients who have high gradients progress to III or IV Heart Failure, they have worse survival.  Factors to consider are impaired quality of life, maybe put them on a treadmill and compare them to healthy patients..                                           

 Quality of life considered with all treatments.   

Creating scar… is just like natural DE – natural scar,  Higher ICD discharge.

Is there is a case for early surgery?  should we try to avoid later complications?

Take Home Message: 

Earlier intervention is an evolving topic; centers with extensive numbers of patients and experience with the full range of issues, treatments and research are key to future action.   No such thing as a “small” heart operation.

Key points: 

We can’t say we are ready for “preventative” surgery but it is a very important topic/issue.

 

Alternatives to surgery:  A decade of alcohol ablation…where do we stand now?

Rick Nishimura, MD

 

Early studies found similar gradient reduction in alcohol ablation compared to myectomy.  Total number of ablations has grown significantly.  Published reports often commended ablation and many cardiac centers performed ablations.  However, structural anatomy must be considered.  Specific patient anatomies vary.  Ablation may be incorrectly located as a result.  Recently published studies have been examined (meta-analysis) with “success” dependent on criteria used.  Overall, ablation has not reduced septums as much as surgery and may have complications of heart block.  Fibrillation effects are unclear after ablation and ablation may cause adverse remodeling.

Myectomy remains the gold standard.  Alcohol Ablation was first done in 1995 to create a localized heart attack.  At first they thought it was low risk high symptoms relief and then they thought that myectomy had no role anymore.  Then ablations took off  because anyone could do it.  Structural anatomy is so important.  Fixed aortic stenosis does not respond to alcohol ablation.  Also, mitral valve abnormalities cannot be dealt with.  Anatomy of the coronary arteries is variable.  So if the septal perforator is not just rightly placed, then no go.  Success overall is very good with approximately  93% in gradient reduction.  However, to achieve the same rate of success as myectomy, success rate is down to 70%.  The complication rate is 1.5% mortality from the procedure within 30 days.  Heart block can result because ablation causes RBBB and myectomy causes LBBB so if you have ablation you can become pacemaker dependent.  V fib can result.  2 – 3% of patients undergoing alcohol ablation at experienced centers will have V fib.  Other complications are also possible 26% of the timevs. 5% for myectomy. 

Clinical outcome:  Gradient and symptoms go down after alcohol ablation and might even further reduce.  They might have subjective and objective improvement right after, BUT, when looking at individual patient response, there are so many different patient anatomies, everyone’s outcome is different.  You cannot predict where the alcohol will go, so sometimes the obstruction cannot be eliminated and then will still be left with obstruction and residual symptoms.  One out of four patients will not have benefit. Four year survival and symptom elimination Is 60%.

Ablation is good for older patients, less and localized hypertrophy, lower gradient, and if you can get a residual gradient of less than 25 higher predictors of success .  The scar in alcohol ablation can cause arrhythmia.  There is no definitive data in VT after alcohol ablation, but with current data available with ICD as secondary prevention, 10.6% and over years, may increase.  There is only short term follow up with alcohol ablation.  With more you follow up, you  will probably see an increase.  The amount of alcohol injected varies from center to center.  The people with the best results of relief inject the most alcohol, but when you look at annual mortality with lower doses of alcohol vs. higher doses, it is higher with the 4 cc. of alcohol and is better with the lower amounts of like 1.8 cc.  True success is less than 75% when compared to myectomy.

Careful patient selection is critical!                                                                                  

Take Home Message: 

 Patients should discuss the pros and cons of both ablation and myectomy surgery before deciding on treatment.  Research with Radio frequency ablation in place of alcohol injection                                                                                                                          

Key points: 

Ablation continues to be an alternative for people with HCM but the heterogeneity of HCM requires individual analysis for specific patients considering its use. Its outcomes are not as good as those seen in surgical patients.

 

 

Surgical myectomy vs. alcohol septal ablation:  What about a randomized trial?  Role of the mitral appparatus

Harry M. Lever, MD

 

 HCM has a very diverse (heterogeneous) presentation.  There is variability in mitral valves, papillary muscles and distribution of hypertrophy.  Asking if ablation is equal to surgery is a complete research question.  Ideally, a clinical trial randomly assigns patients for alternative treatment.  HCM is so heterogeneous with so many anatomical variations that getting enough patients to randomly assign patients to get sufficient comparable subjects for ablation and surgery groups would be nearly impossible.

 Almost 50% of patients are not good candidates for alcohol ablation.  Due to the heterogeneity of HCM, with everyone being made just a little different, a randomized trial is not possible.                                               

 “Symptoms worse after eating!!!”

Take Home Message: 

Consideration of use of randomized clinical trials for comparison of HCM treatment such as ablation vs surgery is an important topic for discussion.  The conclusion, however, is that HCM presents many barriers to use of clinical trials.

 Surgery vs. Alcohol Septal Ablation?  Heterogeneity and relatively small numbers-- randomized, controlled trial very difficult, if not impossible

Key points: 

HCM is an important disease requiring consideration of the best comparative effectiveness studies possible but standard “trials” present major challenges for use in HCM.

Closing:  The Next 50 Years

Barry J. Maron, MD

 

  “No way to try to summarize something like this”          “We do this for our patients” 

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