Is Screening all Young People for Cardiac Disease Cost Effective?

In Western medicine, especially the U.K. and U.S.A., mandatory screening for cardiac disease in young people doesn’t exist.

The NHS currently offers screening for the following:

  • Newborns (blood, cardiac, hearing tests, and physical examination)
  • Pregnancy (foetal abnormalities, blood tests, and infectious disease)
  • Diabetic eye testing (annual follow-ups for cases confirmed in >12 year olds)
  • Cervical (every 3 years for 26-49 year olds, and every 5 years for 50-64 year olds)
  • Breast cancer (50-70 year olds, 70+ individuals can self-refer)
  • Bowel cancer (55-74 year olds)
  • Abdominal Aortic Aneurism (65 year old men. Over 65s can self-refer)

These tests are designed to aid in patient healthcare and to alleviate the long-term financial burden on the heath service, but as you can see, they’re fairly narrow in their scope. Aside from newborns, the vast majority of the screening programmes cater to individuals in later life, or after index presentation/diagnosis. If one suspects an abnormality, then of course, there are many private options available, and in fact, cardiac screening for precursors to sudden cardiac death (such as hypertrophic cardiomyopathy) is in place for young athletes. Given that the estimated number of young people with the abnormality currently stands at 1 in 500, it has been theorised with this and other cardiac diseases in mind, that mandatory screening for young people could ease the cost on the NHS, enhance patient treatment/safety and the emotional fallout that comes as a result of the morbidity associated with serious cardiac conditions.

The results of a nationwide U.K. screening programme known as Cardiac Risk in the Young imply that mass-screening that also encompasses ECG in addition to the standard physical exam and history increases the likelihood of early diagnosis and actually saves money.

The results are the endpoint of a 4-year process, involving roughly 30,000 young persons who were screened using the above methods, all of which were performed and interpreted using the relevant professionals and governing body guidelines.

8.1% of the 30,000 were deemed to produce an abnormal 12-lead ECG, 3.5% had an abnormal physical exam and/or history, and 0.5% showed abnormality in all three areas. 11.7% underwent echocardiography to confirm or deny the presence of dysfunction, 0.9% were referred for cardiac MRI, 1.7% were moved on to longer-term ECG monitoring, and 1.7% had exercise stress testing.

87 abnormalities associated with SCD syndrome were positively diagnosed at the 2-year follow up mark, accounting to 0.3% of the cohort, and 83% of this number was done so using the ECG alone. Interestingly this 83% was found in individuals who presented as asymptomatic, and would likely go undiagnosed otherwise.

The cost of this screening and subsequent treatment of a positive identification is estimated to be 20% lower than the cost of treatment and screening using current requirements, due to its lowering of false positives from 21.8% to 4.3%. This, in turn, lowers the amount of unnecessary follow ups, so this study may have great implications for young athletes, and non-athletes alike in helping to spot these potentially fatal conditions, many of which can be managed.

More on this story and more at: Cardiac Risk in the Young

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Detecting CAD with Vocal Biomarkers

Beyond Verbal, an Israeli company leading the market in voice/emotion analysis software are making headlines thanks to their study with the Mayo Clinic, that shows that voice analysis can indicate the presence of coronary artery disease (CAD).

CAD is responsible for one of the highest cardiovascular mortality rates in developed countries globally, and whilst lower in developing countries, this figure is quickly rising. With this in mind, inexpensive, low-risk  and non-invasive screening methods are a very desirable prospect. Currently, ECG, Exercise Tolerance Testing (ETT), Radionuclide testing and Pharmaceutical Stress Testing are the most common procedures used to screen for CAD, but, aside from ECG, each has contraindications, and/or is fairly invasive. Again, aside really from a simple ECG, each has a middling to significant associated cost attached to it. Technology that could reduce these costs and the potential for unnecessary testing presents a possible alternative to patients being referred to chest pain clinics and such, without a sure fire reason to do so.

Beyond Verbal have already used their vocal analysis software to find audio characteristics associated with Parkinson’s disease and autism, and have now turned their technology to CAD.

The Beyond Verbal/ Mayo Clinic study hypothesised, due to the association coronary atherosclerosis has with other systemic pathologies, that vocal processes and the structures responsible may also be affected.

150 patients, 120 of which presented for angiography of the coronary arteries and 50 healthy, or non-cardiac control patients had their voice recorded prior to the test. Beyond Verbal then used a variety of their analytical software to record three 30 second voice clips from each patient; the first (R1) was a predetermined script, R2 was a description of a positive experience, and R3 was personal like R2, only a negative experience.

The analysed results show a 19-fold increase in the likelihood of CAD in R3, the negative voice clip, irrespective of traditional cardiac risk factors such as age, suggesting there is indeed a link between CAD and voice.

BV hope that future development of this technology can be used to screen patients telephonically.

 

The poster outlining the study can be found here

Beyond Verbal on the web.

The TSP resources relating to CAD can be found here and here.Heart

Ajmaline Provocation in Suspected Brugada

Today, I was present during a Brugada provocation test using ajmaline, a class 1a antiarrhythmic drug much like class 1c drug, flecainide, in that it acts as a Na channel blocker. As its action lengthens the action potential phase 0, in non-pacemaker myocytes, it induces bradycardia, and encourages the transient Brugada rhythm to present itself.

Indications for the test are outlined here, and the procedure itself, is a relatively simple one;

  • Ajmaline is prepared at a total dose of 1mg/kg-1
  • 12 lead ECG is applied to the patient
    • V1 and V2 should be positioned on IC3 or IC2
    • The ECG should be viewable in real time, as well as be printable
  • Intravenous Ajmaline is administered in a 10mg bolus, every 2 minutes
    • Fractions should be administered slowly over 1 minute
  • ECG should be printed after each dose

Indications for terminating the test are as follows:

  • Ajmaline dosage is completely administered
  • Typical Brugada criteria present on the ECG
    • ST coving present in more than 1 right precordial lead
    • J point elevation greater than 2mm
  • Incidence of:
    • PVCs
    • AV Block (2nd° or 3rd°)
    • VT
    • Sinus arrest

During the test, the patient indicated that the initial 10mg was very unpleasant, and caused “a horrible feeling” at the back of her throat. She did say that this initial bolus was the worst, however, and that subsequent injections were bearable, by comparison. Towards the end of the test, i.e., one injection from termination, the patient indicated that her lips had become almost completely numb.

The test, in this case, was negative, and the patient’s ECG showed no changes to suggest Brugada at any point throughout the procedure.

Ajmaline is unlicensed in the UK, but this is not indicative of its level of safety, rather it is because it is manufactured in Germany, and imported to trusts in this country. Curious as to why ajmaline was being used, I asked the nurse practitioner who was on hand to implement the test, who informed me why the trust opted to use ajmaline as oppose to flecainide, when both seemingly do the same thing. She cited the time taken for each pharmaceutical agent to leave the patient after the test; in the event of a negative outcome, ajmaline allows a patient to be discharged safely in around 3 hours, whereas flecainide takes a great deal longer to be removed.

Not knowing the costs associated with each drug, I decided to look for other reasons as to why an imported medication is used in this provocative study, and discovered research by Wolpert et al  published in 2005, that tested ajmaline and flecainide against each other in a blind trial.

22 patients for whom a diagnosis of Brugada was already known, underwent IV flecainide and ajmaline testing, and the results were then studied by 3 physicians who were unaware of the drug being used in provocation.

The results for flecainide showed

  • Significant ST changes in 15/22 of the patients tested (68%)
  • Mean V1 amplitude of 0.19mV
  • Mean V2 amplitude of 0.31mV
  • Mean V3 amplitude of 0.1mV

The results for ajmaline showed

  • Significant ST changes in 22/22 of the patients tested
  • Mean V1 amplitude of 0.22mV
  • Mean V2 amplitude of 0.39mV
  • Mean V3 amplitude of 0.1mV

It is important to note, that whilst these results show a more favourable outcome when using ajmaline over flecainide, in provocative studies, this research is limited in that, despite being a blinded study, it was not a randomised trial and was not repeated. Nevertheless, it does suggest that provocative studies using flecainide may not successfully unmask Brugada syndrome in patients, and its longer life within the patient may favour the use of ajmaline in investigations.

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