Stroke prevention research

J. David Spence

Stroke Prevention & Atherosclerosis Research Centre

Robarts Research Institute

London, Canada

dspence@robarts.ca www.imaging.robarts.ca/sparc

Disclosures • Grants for research from HSF, NIH, CIHR

• Grants for research from Pfizer, Merck, Pan American Labs

• Lecture fees from Pfizer, AstraZeneca, Merck, Novartis, Boehringer-Ingelheim

• Consulting fees from Novartis, Boehringer-Ingelheim

• Interest in www.vascularis.com

Medical research

• A career in medical research is non-linear

• Follow the questions where they lead

• Develop/adapt methods to do so

– “Technological courage”

• One answer leads to another question

• Persistence

• Patience!

– research is the ultimate in delayed gratification – note the dates on the references

My research areas not discussed

• Pseudohypertension

• Effect of grapefruit on drug metabolism

• Vitamins to stroke by homocysteine

• Individualized therapy for hypertension

• Clinical pharmacology of drugs for stroke prevention

• Effects of therapy on 3D carotid plaque volume

The origin of a question 4 key lectures

• Dr. Daria Haust

– atherosclerosis

• Dr. Margot Roach

– Flow disturbances

• Dr. C. Miller Fisher

– Strokes from high blood pressure due to small vessel disease, not atherosclerosis

• Dr. Fraser Mustard

– Atherosclerosis focal, where arteries bend and branch

My starting point • Atherosclerosis occurs at

branches and bends

• Related to flow disturbances

• Antihypertensive drugs might have different effects on flow disturbances, so

• Might have different effects on atherosclerosis

First presented at Neurology Journal Club in Dr. Barnett’s living room in ~ 1972

Effects of antihypertensive drugs on blood velocity

Spence JD, Pesout AB, Melmon KL. Stroke 1977;8;589-594

Effects of antihypertensive drugs on blood velocity

Spence JD, Pesout AB, Melmon KL. Stroke 1977;8;589-594

Effect of hydralazine vs. propranolol in hypertensive rabbits fed cholesterol

Spence JD et al. Atherosclerosis 1984; 50: 325-333

Effect of hydralazine vs. propranolol in hypertensive rabbits fed cholesterol

Spence JD et al. Atherosclerosis 1984; 50: 325-333

Assessing flow disturbances in human beings

Spence JD Clin lnvestig Med 1989;12:82-89.

Wait a minute:

We can see the artery wall!

Composite drawing of all plaques in extracranial carotids

We started with composite drawings of the plaques – but one day in 1990 I asked Maria DiCicco RVT – “Maria, how do I know you’re drawing the plaques the same way from one year to the next?

Measurement of 2-D Plaque area*

* Invented in our lab in 1990 by Maria DiCicco, R.V.T.

“Well, ..there is software in the machine – I could measure the plaques if you want me to.” What? Show me!

79 yo woman 72 yo man

Composite drawing of all plaques in extracranial carotids

We found an enormous dynamic range for total plaque area

Carotid Plaque Area as predictor of events

1,686 patients in our Atherosclerosis Prevention Clinic followed up to 5years During mean followup of 2.5 + 1.3 years: 94 MI, 45 strokes, 44 deaths (27 vascular).

Spence JD, Eliasziw M, DiCicco M et al. Carotid Plaque Area: A Tool for Targeting and Evaluating Vascular Preventive Therapy. Stroke. 2002;33:2916-2922.

Baseline Carotid plaque area as a predictor of events Stroke, MI, Death (after adjustment for risk factors*)

*Age, sex, SBP, tChol, pack-yrs, tHcy, diabetes, Rx lipids and BP

Stroke 2002; 33:2916-2922.

Distribution of carotid plaque area by age groups and sex

Spence JD. Nature Clinical Practice Neurology 2006;2: 611-619.

Plaque progression despite therapy doubles the risk*

*Adjusted for Age, sex, SBP, tChol, pack-yrs, tHcy, diabetes, Rx lipids and BP Stroke 2002; 33:2916-2922.

Medical treatment was failing in half the cases, and they were at double the risk: we needed to do better!

JDS

Paradigm change:

Treating arteries, not risk factors

Instead of treating risk factors to target, since 2003 we treat patients more intensively if their plaque is progressing , regardless of their level

of LDL or other risk factors i.e. – since 2003 our target is now plaque regression

Treating arteries without measuring plaque is like

treating hypertension without measuring blood pressure

Benefit of carotid endarterectomy

Symptomatic severe stenosis: 2-yr reduction of stroke death from 26% to 9% Asymptomatic: 5-yr risk reduction 10% to 5% NNT to prevent 1 stroke in 2 years1: NNT Symptomatic severe >70% age<75 6 Symptomatic severe >70% age>75 3 Symptomatic moderate 50-69% 15 Asymptomatic 67-83* •Predicated on 3% surgical risk, and historical medical therapy

1.Barnett HJM. CMAJ 2004;171: 473-4

TCD microembolus detection

319 ACS patients between 2000 and 2004

10% had microemboli

1-year Stroke Risk

No Emboli Emboli

1% 15.6%

95% CI (1.01 -1.36) (4.1-79)

p<0.0001

Spence JD et al. Stroke 2005; 36:2373-2378.

Spence JD et al. Stroke 2005;36:2373-2378

Stroke risk over 2 years by baseline microembolic status

Biology of ulcers vs microemboli We obtained a grant from HSFO with Rob Hegele and Quim Madrenas to study inflammatory biomarkers and gene expression in carotid stenosis patients with ulcers, microemboli or neither. After 2 years we had only found 7 patients with microemboli; there should have been 20. Where had the microemboli gone? Hypothesis: Had our new paradigm caused microemboli to disappear because more intensive therapy stabilized plaque? We therefore studied prevalence of microemboli in ACS and rate of plaque progression in our clinic patients, before and after the paradigm change in 2002

•468 patients with ACS •199 before Jan 1, 2003, 269 since 2003 •All had baseline microembolus detection by TCD •All followed for at least one year •Database closed July 1, 2008 •4,328 patients followed in our prevention clinics •plaque measurements in successive years •Rate of plaque progression per year computed by year, from 1997 to 2007

Methods:

11%

2.2%

P<0.001

Spence JD et al. Arch Neurol. 2010;67:180-6

Decline of microemboli with more intensive medical therapy

< 5% of ACS patients can now benefit from carotid endarterectomy or stenting

Annual rate of plaque progression in ACS patients before and since 2003

n= 346

P<0.0001

Spence JD et al. Arch Neurol. 2010;67:180-6

Kaplan-Meier Survival free of stroke, death, MI

logrank test p<0.0001 logrank test p<0.0001

Spence JD et al. Arch Neurol. 2010;67:180-6

Decline in events in ACS with more intensive medical therapy

No emboli

n=431

Microemboli

n=37

p

Before

2003

n=199

Since

2003

n=269

p*

Stroke in year 1 1.4% 10.3% 0.016 3.3% 1% 0.155

Stroke in year 2 1.8% 18.5% 0.001 5.5% 0% 0.006

MI in year 1 2.2% 6.9% 0.165 4.9% 0.5% 0.007

MI in year 2 1.4% 3.2% 0.394 2.7% 0.5% 0.104

Death in year 1 2.8% 10.3% 0.069 4.4%% 2.4% 0.386

Death in year 2 2.1% 3.7% 0.477 3.8% 0% 0.044

CEA year 1 1.4% 12.9% 0.003 2.7% 1.9% 0.739

CEA year 2 0.3% 3.7% 0.146 1.1% 0% 0.499

Stroke, death or

CEA 1st 2 years

6.5% 32.4% <0.0001 14.1% 4.5% <0.0001

Stroke, death, MI

or CEA 1st 2 years

8.6% 32.4% <0.0001 17.6% 5.2% <0.0001

Spence JD et al. Arch Neurol. 2010;67:180-6

Carotid plaque measurement

Summary

Plaque measurement is useful for:

Managing patients

Stratifying risk

Managing resources

Encouraging patients to follow regimen

Monitoring success of therapy

Genetic research

Quantitative traits for linkage studies

Studying effects of new therapies

Much smaller sample size x duration

Proof of concept studies in human subjects

Dose-finding studies

Ulceration as categorical variable

Grade:

0 ulcers

1-2 ulcers

3-5 ulcers

>5 ulcers

Ulceration vs microembol in ACS

Madani A….Spence JD. Neurology 2011 Aug 23;77(8):744-50.

At least 90% of ACS patients should be treated only medically

•The treatment of choice for ACS should be intensive medical therapy •Less than 5% of ACS patients can benefit from revascularization •Only those with microemboli should be considered for endarterectomy or stenting

3D ultrasound measurement of carotid plaque volume and vessel

wall volume

Developed with Dr. Aaron Fenster and Dr. Grace Parraga at Robarts

First measurement of carotid plaque volume 1994

Rendered plaque volume

Disk segmentation method

Vessel Wall Volume

Egger M, Spence JD, Fenster A, Parraga G. Validation of 3D Ultrasound Vessel Wall Volume: An Imaging Phenotype of Carotid Atherosclerosis. Ultrasound Med Biol. 2007 Jun;33(6):905-14.

Progression of plaque volume predicts events

Stroke 2013;44:1859-1865

Treating arteries without measuring plaque is like

treating hypertension without measuring blood pressure

The Future

Imaging vulnerable plaque

Bogiatzi C, Cocker M, Beanlands R, Spence JD. Identifying high-risk asymptomatic carotid stenosis. Expert Opin Med Diagnostics 2012, Vol. 6, No. 2: 139–151.

CAIN Project 2 Histological validation of preoperative imaging of vulnerable

plaque in patients scheduled for carotid endarterectomy

3D US ulceration

3D US plaque roughness

Plaque composition by MRI and 3D US

Plaque inflammation by PET/CT

Ulcer

3D histology

Dietary cholesterol is important • “High cholesterol (1021 mg/day), high saturated fat (P/S ratio 0.4) diet

increased serum cholesterol (23%) by raising the cholesterol concentration in very low-density lipoproteins (59%), low-density lipoproteins (15%), and high-density lipoproteins (30%).”1

• “Variation in cholesterol rather than the proportions of saturated and polyunsaturated fat had the most influence on LDL-cholesterol levels. Among non-Caucasians it was the only significant factor.”2

1.Tan MH, Dickinson MA, Albers JJ, Havel RJ, Cheung MC, Vigne JL. The effect of a high cholesterol and saturated fat diet on serum high-density lipoprotein-cholesterol, apoprotein A-I, and apoprotein E levels in normolipidemic humans. Am J Clin Nutr 1980 December;33(12):2559-65.

2. Fielding CJ, Havel RJ, Todd KM et al. Effects of dietary cholesterol and fat saturation on plasma lipoproteins in an ethnically diverse population of healthy young men.

J Clin Invest 1995 February;95(2):611-8.

Propaganda • is communication aimed at influencing the

attitude of a community toward some cause or position. As opposed to impartially providing information, propaganda in its most basic sense, presents information primarily to influence an audience. Propaganda often presents facts selectively (thus lying by omission)...

http://en.wikipedia.org/wiki/Propaganda

Egg propaganda

• Egg marketers were charged by the FDA with false advertising 20 years ago, and convicted

• They lost their appeal

• They’ve spent hundreds of $millions on propaganda since then

http://nutritionfacts.org/video/eggs-and-cholesterol-patently-false-and-misleading-claims/

Egg propaganda

Rests on

• A red herring

– Fasting cholesterol is what matters

• And a half-truth

– “eggs can be part of a healthy diet for healthy people”

Egg yolks in the Health Professionals Study

• 37, 851 men aged 40 to 75 years at study outset and 80, 082 women aged 34 to 59 years at study outset, free of cardiovascular disease, diabetes, hypercholesterolemia, or cancer.

• 866 CHD, 258 strokes in men in 8 yrs FU • 939 CHD, 563 strokes in women /14 yrs No significant risk in healthy participants, but: In new onset diabetics, RR of 1egg/day risk vs. <1/week

• men, 2.02 [95%,1.05-3.87; P for trend = .04]

• women, 1.49 [0.88-2.52; P for trend = .008]).

Hu FB et al. JAMA. 1999;281:1387-1394

Egg yolks and CHD risk

Nationally representative sample of 9,734 adults aged 25 to 74 followed 20 years • Adjustment for age, sex, race, serum cholesterol, BMI,

diabetes mellitus, SBP, education and smoking • No risk in healthy participants, but in diabetics: • 6 eggs per week vs <1 - CHD RR 2.0 (95% CI 1.0-3.8) Qureshi AN et al. Med Sci Monit. 2007;13(1):CR1-8

Egg yolks and CHD risk

Greek diabetic cohort

per 10 grams of egg per day (1/6th of an egg)

• overall mortality

HR 1.31 (95% CI 1.07 to 1.60)

• cardiovascular mortality

HR 1.54 (95% CI, 1.20 to 1.97)

• A daily egg increased coronary risk 5-fold

Trichopoulou A et al. J Intern Med 2006;259(6):583-591.

Egg yolks are not OK

• Recommended cholesterol intake for high-risk patients1: <200mg/day

• 1 large egg yolk contains ~237 mg of cholesterol • Egg yolks only increase ordinary LDL by 10%, but increase LDL oxidation by 34-39%2,3

• Eggs increase risk of diabetes and events in meta- analysis4

1. Catapano AL et al. Atherosclerosis 2011;217 Suppl 1:S1-44. 2. Levy Y et al. Ann Nutr Metab 1996;40:243-51. 3. Schwab US et al. Atherosclerosis 2000;149(1):83-90. 4. Li Y, et al. Atherosclerosis 2013 229(2):524-30

Fasting lipids: the carrot in the

snowman

Diet is about the postprandial state, not about fasting

lipids

Spence JD. Can J Cardiol 2003;19:890-2.

Hardee’s Monster Thickburger

• 2/3 pound beef

• 4 strips bacon

• 3 slices cheese

• Mayo

1420 Calories

107 g Fat

210 mg cholesterol

Dietary Toxins:

DF

Egg yolks Egg whites – good source of protein 1 large egg yolk contains ~237mg of cholesterol -More than the Hardee’s Monster Thickburger - more than 4 days’ worth of meat for the Cretan Mediterranean diet, which is the more effective at reducing heart attacks and strokes.

Stopping egg yolks after the heart attack would be like

quitting smoking after the lung cancer is diagnosed

What about omega-3 eggs?

They have omega-3 oils from feeding flax to chickens, but just about as much cholesterol

Better you should eat the flax seed, and leave the chicken out of it!

Egg-yolk years as a risk factor

Spence JD, Jenkins DJA, Davignon J. Atherosclerosis 2012; 224:469-473

Independent of Sex, smoking, blood pressure, BMI, diabetes and serum cholesterol

Effect of egg yolks independent of other risk factors

Spence JD, Jenkins DJA, Davignon J. Atherosclerosis 2012; 224:469-473

Effect of egg yolk and smoking additive

Smoking and

egg yolk

consumption

Little-smoking

little-egg eaters

(Pack-years <10,

egg yolks

quintiles 1 or 2)

n=95

Little-smoking

big egg eaters

(Pack-years<10,

egg yolks

quintile 4 or 5)

n=284

Smoking little-

egg eaters

(Pack-years >10,

egg yolks

quintile 1 or 2)

n= 185

Smoking big

egg-eaters

(pack-yrs >10,

egg yolks top

quintile)

n= 155

Plaque area

(mm2)

69.16 + 89.05 122.39 + 114.48 153.73 + 141.76 213.61 + 164.62

Increase in

plaque area

(mm2)

Comparator 53.23 84.57 144.45

Ratio Comparator 1.77 2.22 3.09

Spence JD, Jenkins DJA, Davignon J. Atherosclerosis 2013; 227: 189–191

Dietary recommendations for vascular patients

• NO egg yolks egg whites, Egg Creations

• Meat of any animal: 4 oz. every OTHER day

• High intake of olive oil, Canola oil

•Whole grains, vegetables, fruit, legumes

• Avoid deep fried foods, hydrogenated oils (trans fats)

To accomplish this, patients need to think of their meatless day not as a punishment day, but as a gourmet cooking class day:

“Having fun learning how to make healthy eating tasty”

Spence JD. How to prevent your stroke. Vanderbilt University Press 2006

Where to next?

• Randomized trial of treating arteries vs. usual care

• Extremes of atherosclerosis and • Genomics • Intestinal microbiome

Atherosclerosis only half explained by traditional risk factors

Spence JD. Nature Clin Pract Neurol 2006; 2: 611-619

Quantitative traits: - unexplained atherosclerosis - unexplained protection

•Reduces by ¾ the sample sizes needed for genomic studies •A way of finding new therapeutic targets

Lanktree MB et al. Circ Cardiovasc Genet 2010; 3: 215 - 221. Spence JD. Atherosclerosis 2012;223:98-101.

Intestinal microbiome – a biological and medical revolution

3 trillion bacteria in our intestines – they convert nutrients to metabolites that get into our bloodstream and have profound metabolic effects on us Economist, August 18-24, 2012

Intestinal microbiome and diet

Tang WHW et al. N Engl J Med 2013;368:1575-84.

L-carnitine from red meat and lecithin from egg yolks Converted by intestinal bacteria to trimethylamine; oxidized in the liver to TMAO

TMAO increases stroke/death/MI

Tang WHW et al. N Engl J Med 2013;368:1575-84.

Intestinal microbiome and atherosclerosis

• Recruit 500 patients at the extremes of atherosclerosis • Obtain samples of blood, urine, stool, dietary info • Extract and bank DNA for future genomic studies as

funded • Extract DNA from stool • Analyze the profile of bacteria in patients with

unexplained atherosclerosis vs. Protection from atherosclerosis

• Study their complete metabolic profile • Find panels of good bacteria to repopulate the intestine

of patients with bad bacteria that are causing excess atherosclerosis

• An entirely new way to prevent heart attacks and strokes!

It takes a team • SPARC team to recruit patients and obtain

samples • London Regional Genomics Centre to extract

and bank DNA • Dr. Emma Allen-Vercoe at Guelph to extract

and bank the DNA from stool • Dr. Greg Gloor to analyze the intestinal

populations using RNA methods • Dr. Jonathan Swann at Reading University, UK

– metabolomics • Dr. Gregor Reid – make sense of the findings,

design panels of therapeutic bacteria

Acknowledgements 3-D Ultrasound technology Genetics Drs. Aaron Fenster, Grace Parraga Dr. Rob Hegele Measurements Lab Manager 2-D : Maria DiCicco RVT Tisha Mabb 3-D: Craig Ainsworth, Funding Anthony Landry, Chris Blake, NINDS Micaela Egger, Christiane Mallet, Silvia Riccio HSF Ontario Bernard Chiu, Shayna McKay, Adam Krasinsky CHRI Ulcers Dr. Vadim Beletsky, Jeremy Mason

Plaque composition Jeremy Mason, Dr. Joseph Awad TCD Study Dr. Arturo Tamayo MRI Dr. Claudio Munoz Dr. Brian Rutt Scanning PET/CT Maria DiCicco RVT Dr. Jean-Luc Urbain Janine Desroches RVT Dr. Ting Lee

Acknowledgements

Maria DiCicco Aaron Fenster Grace Parraga R.V.T. Ph.D. Ph.D. Plaque area Plaque volume Vessel wall volume Plaque roughness, texture 3D U/S

Google: Orion photos: M4; Orion nebula

Medical scientists are like astronomers – but in thrall to the wonders of biology and medicine Advances in Genetics and Imaging are our Hubble Telescope “It is the joy and the obligation of the physician to be a perpetual student.” Sir William Osler

http://www.imaging. robarts.ca/sparc dspence@robarts.ca