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Wednesday, September 23, 2009

Major nationwide shortage of isotope used in nuclear stress testing

Here's a story that I have not seen widely published or discussed. 

There is a major nationwide shortage of Technitium-99m (Tc-99m), also known as sestimibi.

Tc-99 is used in 80% of this nation's radiopharmaceuticals, including nuclear stress testing. 

All summer long, Cardiologists have had to ration their use of this agent. This has greatly affect their use of nuclear stress testing. 

They have also reverted back to using thallium-201. This was the agent used prior to Tc-99m. Unfortunately, thallium is a less that ideal substitute. Its test requires more time for acquisition, it has a lower-energy which leads to lower quality pictures and there is also a higher rate of false positives. Importantly, there is also a higher radiation exposure to the patient. 

How did this happen?
  • In mid-May, Atomic Energy of Canada announced that the Chalk River high-flux reactor would be shutting down due to a heavy water leak
  • This lead to a shortage of Tc-99m since the reactor produces the largest amount of molybdenum-99 - which decays into Tc-99m.
  • Making matters worse, a reactor in the Netherlands also shut down this summer for maintenance
We are doing what we can but we need a more stable supply of these important radiopharmaceuticals.

Please support Rep. Edward Markey's American Medical Isotopes Production Act. This legislation calls for the production of molybdenum-99 in the USA. It is supported by ASNC, the ACC and ACR

For more info on this important topic, you can read Dr Mylan Cohen's (President-Elect of ASNC) interview.

Monday, September 21, 2009

Green Tea and Heart Disease

This is an interesting one.

The largest trial to date came from Japan. In the Ohsaki Studay, published in JAMA in 2006, investigators enrolled 40, 000 patients. After 11 years, "Green tea consumption was inversely associated with mortality due to all causes and due to cardiovascular disease." Interestingly, "the inverse association with all-cause mortality was stronger in women."

While still speculative, the possible mechanisms include green tea's antioxidant properties as well as its ability to help cholesterol and high blood pressure. 

Therefore, while not definitive, there is definitely no downside to drinking green tea. There is the possibility that it might have a benefit, especially in women. 

Friday, September 18, 2009

Trail Running

When I was in medical school, I feel in love with mountain biking and exercising in the woods.

Now that I am a busy Interventional Cardiologist and father of 3 growing girls, I do not have the time to put my bike on the car and drive to a place to bike.

Instead, I have fallen in love with trial running. I'm very fortunate to live ~ 1 mile away from The Fairfield Audubon. There are miles on trails where mountain biking is not allowed but running/walking is encourage.

Trail running gets me out in nature. Its a terrific way to cross-train. It greatly improves my balance and is a terrific for strengthening my core. What can be better than running down a single-track patch, jumping over logs and roots, balancing on small wooden planks over wet lands, all while listening to the birds.

I just got back for a hard 4 miler - I feel totally rejuvenated

Here's some pictures I snapped with my BlackBerry along the way

Thursday, September 17, 2009

Guidelines for the Diagnosis and Management of Syncope - European Society of Cardiology

The European Society of Cardiology has just published new guidelines for the diagnosis and management of syncope (Eur Heart J 2009;Aug 27:[Epub ahead of print].)

Cardiosource's Fred Morady just wrote an excellent synopsis of 10 points to remember from the new guidelines.

I like it so much, I am reproducing below. If you want to read it from its original site.

Perspective: The following are 10 points to remember from these syncope guidelines, developed by the European Society of Cardiology:

1. The two most common causes of syncope are neurocardiogenic syncope and cardiac disorders, which together account for >50% of syncopal episodes.

2. The initial evaluation of patients >40 years should include sequential right and left carotid sinus massage for 10 seconds; asystole >3 seconds with reproduction of symptoms is indicative of carotid sinus syndrome.

3. The main indication for tilt testing is to confirm neurocardiogenic syncope when this diagnosis is suspected. Tilt testing is of no value for assessing the response to therapy.

4. Implantable loop recorders may be more cost-efficient than conventional monitoring or external loop recorders for providing a diagnosis in patients with sporadic syncope.

5. Electrophysiological testing is unnecessary in patients with syncope and an ejection fraction <30-35%, because such patients are appropriate candidates for an implantable cardioverter-defibrillator regardless of the results of the electrophysiological test.

6. Electrophysiological testing may be useful in patients with syncope and suspected intermittent bradycardia, atrioventricular block, or paroxysmal tachycardia.

7. First-line therapy of neurocardiogenic syncope consists of patient education on hydration, high salt intake, avoidance of triggers, recognition of prodromal symptoms, supine posture, isometric contraction of large muscle groups, and avoidance of alcohol.

8. The majority of randomized, placebo-controlled trials have shown that beta-blockers, disopyramide, scopolamine, midodrine, clonidine, and serotonin reuptake inhibitors do not prevent neurocardiogenic syncope.

9. When evaluated in double-blinded fashion, pacing did not significantly reduce the recurrence rate of neurocardiogenic syncope.

10. Unexplained syncope is a major risk factor for sudden death in hypertrophic cardiomyopathy if it occurred within 6 months before evaluation.

Wednesday, September 16, 2009

Medication Noncompliance

At least a quarter of people with heart disease don't take vital medicines they have been prescribed to prevent heart attacks and strokes.

This is a really big problem.

Of all the specialties in medicine, Cardiology has an a overwhelming amount of data to support the medications we prescribe.


- Statins: very effective in reducing events in both the primary and secondary situations

- ACE inhibitors/ARBs: controls blood pressure, reduces events in patients with vascular disease, controls heart failure

- Beta blockers: Protects the heart after a heart attack

- Aspirin and clopidogrel (Plavix): vital for preventing clots in fresh stents

I could go on and on ...

However, these medications do not work if they are not taken consistently, in the correct way.

Make sure you understand why you take a specific medication and how to take it correctly.

Sent from my Verizon Wireless BlackBerry

More on Afib and warfarin

In my previous blog, I discussed some of the risk factors for stroke in patients with atrial fibrillation (AF).

Another way physicians assess a patient's risk of stroke with AF is to calculate a patient's CHADS score.

CHADS is a mneumonic:

1 - Congestive Heart Failure (1 point)
2 - Hypertension (1 point)
3 - Age over 75 years (1 point)
4 - Diabetes Mellitus (1 point)
5- Stroke or TIA history (2 points)

(Mitral Stenosis or prosthetic heart valve carry similar risk and also indicate Warfarin)

1. Patients with CHADS Score >2 (CVA risk >5% per year): should be on warfarin with goal INR 2.0 to 3.0

2. Patients with CHADS Score >1 (CVA risk >4% per year): could be on warfarin or aspirin

3. Patients with CHADS Score 0: can be maintained on aspirin 81 to 325 mg daily

All of this should be discussed completely with your physician. All patients should have a complete understanding of their risk of stroke and their candidacy for aspirin or coumadin.

In the not to distant future, a new class of medications (factor 10a inhibitors) will be available and will hopefully replace warfarin with improved safety and similar efficacy.

Gage (2004) Circulation 110:2287

Sent from my Verizon Wireless BlackBerry

Tuesday, September 15, 2009

Risk Stratification for Stroke in Atrial Fibrillation

Understanding a patient's risk for stroke is an important consideration in recommending which type of medication to perscribe to try and prevent a stroke.

Here is some research:

High-Risk Factors:
  • Mitral stenosis
  • Prosthetic heart valve
  • History of stroke or TIA
Moderate-Risk Factors:
  • Age > 75 years
  • Hypertension
  • Diabetes mellitus
  • Heart failure or decrease heart function
Less-Validated Risk Factors:
  • Age 65-75 years
  • Coronary artery disease
  • Female gender
  • Thyrotoxicosis
Dubious Risk Factors:
  • Duration of atrial fibrillation
  • Pattern of atrial fibrillation (paraoxysmal vs persistent)
  • Left atrial diameter
I recommend all patients with atrial fibrialltion discuss their risk factors with their physician and devise a treatment plan based on an evidenced-based data.
Chest. 2004;126:429S
Circulation. 2005; 112:1687

Wednesday, September 9, 2009

Safety vs Efficacy?

I have always been intrigued by this simple yet very complex conundrum. What's more important: safety or efficacy.

Safety: Is the treatment/drug safe? = does it cause harm?

Efficacy: Does the treatment/drug work? = Does the it do what you want it to do?

I've been thinking about this question for the past two day, ever since I read a recent report from JACC regarding the new medication dronedarone. Dronedarone is a new treatment for suppression of atrial fibrillation (AF). Its major selling points are that is has a short half life and less toxicity. Amiodarone is the drug that it is trying to compete with. Amiodarone does a great job of suppressing atrial fibrillation but is toxic. Amiodarone is iodine based and can be toxic to the thyroid, lungs, liver and skin.

The recent trial was a meta-analysis comparing 4 trials which looked at amiodarone vs placebo and 4 trials which looked at dronedarone vs placebo. "Compared to placebo, amiodarone reduced the odds of recurrent AF by 88% and dronedarone reduced the odds of recurrent AF by 21%. Compared to dronedarone, amiodarone reduced the odds of recurrent AF by 51%, but increased the odds of all-cause mortality by 61% and increased the odds of drug discontinuation because of an adverse drug effect by 81%."

Therefore: the authors concluded that "For every 100 patients treated with dronedarone instead of amiodarone, one may expect that 23 more patients will have recurrent AF and that there will be one less death and six fewer patients with adverse events requiring drug discontinuation."

  1. Amiodarone works better than donedarone for suppression of AF
  2. Donedarone is safer than amiodarone

Question I have:

  1. How do I decide which drug to give?
  2. Should it be my decision or my patients decision?
  3. Which patients will I give which drug to?
  4. Should all physicians be required to discuss both medications with the patient?

What do you think?

J Am Coll Cardiol 2009;54:1089-1095.

Tuesday, September 8, 2009

When do strokes and heart attacks occur?

"Results of a population-based study show a higher incidence of stroke in men older than 75 years and in women older than 65 years. This is in contrast to a higher incidence of acute myocardial infarction observed in men younger than 55 years."

"Case fatality rates at 30 days were similar for stroke and acute myocardial infarction (9.80% and 9.84%, respectively). "

"For stroke patients, independent factors associated with higher case fatality rates at 30 days included age 85 years and older, cardioembolic and hemorrhagic strokes, the first study period (2001 to 2002), history of acute myocardial infarction, and glycemia greater than 7.8 mmol/L. Hypertension (p < 0.001) was more frequent in stroke patients."

"For acute myocardial infarction patients, independent factors included age >85 years at onset, the first study period (2001 to 2002), history of hypercholesterolemia, diabetes, tobacco consumption, and glycemia at onset greater than 7.8 mmol/L. The prevalence of male sex (p < 0.001), hypercholesterolemia (p = 0.002), and diabetes (p = 0.004) was greater in acute myocardial infarction patients."


TimelyMed for BlackBerry reminds you to take your pills

Here's a great program for all you BlackBerry users who also need to remember to take medications:


The developers behind TimelySMS have launched a new app called TimelyMed. Just as the name suggests, TimelyMed reminds you to take your medication with a friendly alert.

Features of TimelyMed include:

  • Schedule Medicine Alerts
  • Set frequency as one 30 mins, 1 hours, 2 hours,… 24 hour.
  • Enable or disable alerts
  • Autostarts with device start
  • Snooze Alarm
  • Dismiss Alarm

TimelyMed costs $9.99 in the BlackBerry Cool store.

Friday, September 4, 2009

This Weeks Tweets

  • People w naturally thin thighs may be @ greater risk for developing heart disease & dying an early death. http://bit.ly/j9eGo
  •  September is P.A.D. Awareness Month. http://bit.ly/33peen
  • Future?: Cath all patients prior to vascular surgery http://viigo.im/0MSz
  • I believe this approach, using a wire 2 measure the pressure diff across a blockage, is the best http://viigo.im/0MSj
  • FAME at ESC: benefits of FFR hold up at 18 months -- http://viigo.im/0MSb
  • http://viigo.im/0MRY
  • First Genetic Link Between Reptile And Human Heart Evolution Discovered By Gladstone Scientists http://viigo.im/0MRJ
  • Mediterranean diet might delay need for drugs in diabetes - once again research proves that Med diet is the best http://viigo.im/0MRd
  • Only three cigarettes a day significantly increases cardiovascular disease risk http://viigo.im/0MR2
  • Although I look dorky, I always where fit-over lead glasses while doing interventions to protect my eyes http://viigo.im/0MR0
  • Statins Prevent Heart Problems after Vascular Surgery: I'm doing this 4 all my pts having vascular surgery http://viigo.im/0MOX
  • "Live healthy" = watch their weight, exercise daily, breast-feed their babies and limit alcoholic beverages http://bit.ly/QQdfy
  • Women can cut their risk of breast cancer by almost 1/2 if they live healthy http://bit.ly/QQdfy
  • Washington State Reverses Course on medicated stents, Votes Against Restricting Access http://viigo.im/0MOG
  • @Oathealth Great job getting the word out regarding heart failure. While we r making strides w heart attacks, HF cont's 2 b a huge problem
  • RT @RealAge: Genetic clues may lead 2 new melanoma cancer therapies-exciting, melanoma hit close 2 home recently: http://tinyurl.com/no9rhn
  • @dr_oneal This is what is postulated. This is why beta-blockers work too. Another option is to use exercise which naturally lowers the HR
  • Treating angina patients with a drug that slowed down their hearts lowered the risk of attacks by 42%. http://bit.ly/WnCWm
  • U.S. Life Expectancy Reaches 77.9 Years http://viigo.im/0LXO