Dr Richard Bogle PhD FRCP FESC FACC DHMSA
Consultant Cardiologist
  • Home
  • NHS Practice
    • NHS Practice
    • St Helier Hospital
    • Epsom Cardiac Day Unit
    • St George's Hospital Radial Lounge
    • Echocardiography
  • Biography
    • Qualifications
    • About me >
      • Curriculum vitae
    • Appraisal and Revalidation
    • BCIS Angioplasty Audit
    • Publications
    • Recent abstracts
    • Research
    • Charitable activity
  • The Heart
    • Cardiac Investigations >
      • AliveCor ECG monitor
      • Guide to investigations for suspected angina
      • CT calcium scoring
      • Electrocardiogram (ECG)
      • Exercise treadmill test
      • Echocardiogram
      • Valve disease
      • Coronary Angiography
      • Pressure Wire Studies
      • Intra-vascular Ultrasound
    • Arrhythmias >
      • Atrial fibrillation >
        • Stroke Risk in AF
        • New Oral Anticoagulants
        • Presentations on AF
      • Atrial flutter
      • Pre-excitation syndromes
      • Ventricular ectopic beats
      • Ventricular arrhythmias
      • Pacemaker
      • DC Cardioversion
    • Cardiomyopathy
    • Coronary heart disease >
      • Cardiac syndrome X
      • Coronary Angioplasty
      • Coronary bypass surgery
    • Dizziness and blackouts
    • Fitness to fly
    • Fitness to drive
    • Heart Failure
    • Hypertension >
      • Patients guide to blood pressure medication
      • Home blood pressure monitors
      • Hypertension diet
      • Laragh's method
      • Renal sympathetic ablation for hypertension
      • Conn's Syndrome
    • Heart Screening >
      • Sports Cardiology
      • Cardiovascular Disease Risk
    • Medications >
      • Glyceryl trinitrate
    • Patient information leaflets
  • News and Links
  • Miscellany
    • History of Medicine
    • History of Coronary Angiography and Angioplasty
    • Stamps in Cardiology
    • A History of Medicine in 100 Objects
    • BSE Acceditation Course Introduction
    • BSE Acceditation Course Physics
    • BSE Acceditation Course Anatomy and Function
    • BSE Acceditation Course Mitral
    • BSE Acceditation Course Aortic
    • BSE Acceditation Course Congenital
    • BSE Acceditation Course Pericardium
  • Blog
  • RACPC Form
  • Cardiology Teaching St Helier Hospital

Coronary angiography: Has the gold standard become tarnished?

14/6/2014

1 Comment

 
In 1958 Mason Sones famously, and apparently accidentally, performed the first coronary angiogram at the Cleveland Clinic. From then on much of the clinical care of patients with ischaemic heart disease was based on research that relied heavily on the visual interpretation of the coronary angiogram. However it wasn't long before papers stared to appear which questioned the accuracy and reproducibility of these visual estimates. One paper from 1976 reported than nearly half the time a group of experienced cardiologists could not agree on the presence of significant coronary artery disease. Other studies followed alleging to to demonstrate the benefits of performing quantitative coronary angiography using computers to assist in the measurement of the degree of narrowing. These methods were more reproducible than eyeballing the angiogram but still there was disagreement and the methodology was time consuming.

Take for example this angiogram on shown below. Do you think the this LAD stenosis is flow limiting? Why not vote here and see what others think?
Picture
By early 1990's the literature on the accuracy of angiogram went quiet. Cardiologists had other things on their mind - namely coronary angioplasty and stenting. Angiography was the test which fuelled the fire of angioplasty and so the problems with assessment of flow limiting lesions and lesion significance drifted into the background. The occulo-stenostic reflex was strong. Cardiologists needed their angiograms too much to call into question the ability of the test to diagnose and classify the severity of the coronary lesions.  This was the era of eminence-based medicine when expert opinion trumped anything else. The poor reproducibility and difficulty in assessment of lesion was forgotten.

When you learn angiography you quickly realise that the interpretation is difficult. When you work for a number of bosses you start to see a difference in their practice. Some always see a moderate lesion as severe, or a severe lesion as critical. The phrase "the angiogram often underestimates the severity of disease" is often be heard in the catheter lab control room as the guide catheter is being opened ready for angioplasty. Whilst there is usually agreement about the mild (<30%) and severe (>80%) lesions it is the moderate ones which are most difficult and unfortunately most common.

As I teach my fellows the percent stenosis is the wrong way to think about lesions, rather we should say whether we believe a lesion to be flow limiting or not. Flow limitation is dependent on the stenosis but also on the reference vessel size, the lesion length, the size of the territory supplied by the vessel and the presence or absence of collaterals. The issue of interpretation is vital to the individual patient since it determines what treatment is recommended, You don't want a cardiologist to put in a stent or offer bypass surgery if your coronary artery lesion is not flow limiting.

Recent studies have revealed what we knew all along namely that when coronary artery disease is moderate it is not possible to accurately know by visual assessment whether the lesion(s) are flow limiting or not. We need better methods not based on anatomy but rather on physiology. I have previously written about the RIPCORD trial but recently a large French registry has published its results which support the idea that the angiogram is difficult to interpret and that use of a pressure wire to measure fractional flow reserve (FFR) alters the cardiologists decision making.

The R3F study looked at 1000 people having a diagnostic angiogram. The vessels were assessed and significant lesions documented. The patients symptoms and the results of any non-invasive investigations were considered and a recommendation made as to whether the patient should have medical therapy, angioplasty or bypass surgery. After this the cardiologists performed a pressure wire measurement (FFR) of any stenosis. The results were then used to determine whether the stenosis was flow limiting and with this information in hand the treatment recommendation adjusted. So for example if a patient had a 40% stenosis on the angiogram with medical therapy recommended initially but then the pressure wire was significant (e.g. FFR 0.74) the recommended treatment would be to offer an angioplasty.

Using the pressure wire data the overall number of people recommended for medical therapy, angioplasty or bypass did not change but the decision for an individual patient changed 43% of the time. Overall the decision changed in 33% of patients initially recommended to have medical therapy and 50% of patients recommended to have angioplasty or bypass surgery.

These results are very important for individual patients since the treatment recommendation means the difference between just taking tablets versus having a procedure or an operation. We don't know yet whether a pressure wire guided approach makes a difference to clinical endpoints such as survival, mortality, rates of heart attacks and a large trial is needed to answer this question. 

For the moment when a moderate stenosis is diagnosed the patient should be asking their cardiologist what is the FFR?
1 Comment
Anne Marie Cunningham link
17/11/2014 05:17:29 am

Hello Richard,
Thank you very much for this. As a GP I was not aware of this debate in cardiology. Can I ask how a pressure wire study is performed? Would it take place during the angiogram? What is the place of MRI in this assessment? I hear more about cardiac MRI these days but am not quite sure what the rationale is for its use.
Thanks again
Anne Marie

Reply

Your comment will be posted after it is approved.


Leave a Reply.

    RSS Feed

    Picture

    Dr Richard Bogle

    The opinions expressed in this blog are strictly those of the author and should not be construed as the opinion or policy of my employers nor recommendations for your care or anyone else's. Always seek professional guidance instead.

    Archives

    November 2019
    March 2016
    February 2016
    May 2015
    April 2015
    March 2015
    February 2015
    January 2015
    December 2014
    November 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014
    January 2014
    November 2013
    October 2013
    August 2013
    July 2013
    June 2013
    May 2013
    April 2013
    March 2013
    February 2013
    January 2013

    Categories

    All
    Ablation
    Acute Coronary Syndromes
    Acute Coronary Syndromes
    Adherence
    Angioplasty
    Anticoagulants
    Arrhythmia
    Association
    Atherosclerosis
    Atrial Fibrillation
    Auenbrugger
    Bergamot
    Brugada
    Calcium Channel Blockers
    Cancer
    Cardiovascular Risk
    Chest Pain
    Cholesterol
    Cleveland Street
    Clinical Examination
    Colchicine
    Compliance
    Concordance
    Congenital Heart Disease
    Coronary Artery Disease
    Coronary Artery Disease
    C-reactive Protein
    Decision Aids
    Diet
    Ectopics
    Eggs
    Ezetimibe
    Frailty
    Frank's Sign
    Guidelines
    Hawthorne Effect
    Heart Failure
    History Of Medicine
    Hypertension
    ICD
    Internet
    Interventional Cardiology
    Joseph Rogers
    Lipids
    Malaria
    Marathon
    Medicines
    Nice Guidelines
    Nitrovasodilators
    NOAC
    Nudge
    Nutrition
    OCT
    Palpitations
    Pharmacy
    Pressure Wire
    Proteus
    Salt
    Smoking
    Spironolactone
    Statins
    Statistics
    Stent
    Stress
    Stroke
    Syndrome X
    Takotsubo
    Valve-disease
    Vein Grafts
    Ventricular Ectopics
    VF/VT
    Warfarin
    Weekend Working
    Workhouse

    View my profile on LinkedIn
Return to home page

Privacy Statement
Disclaimer
© Dr Richard Bogle 2020
patient feedback
Photo used under Creative Commons from peddhapati