Violent Collision of Antegrade with Retrograde

Coronary Flow Causing the First Endothelial

Injury, Starting a Plaque and Breaking the Cap

of Vulnerable Plaques

The 10th Central Vietnam Open Congress of Cardiology

14:05-14:20 Friday July 12th 2019

Thach Nguyen, MD FACC FSCAI

Tan Tao U, School of Medicine, Long An Vietnam,

Methodist Hospital Merrillville IN USA,

Background 1

How to create an animal model for

atheroslerosis

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=2ahUKEwj215zUqZvjAhVKBc0KHZ8QAI8QjRx6BAgBEAU&url=https%3A%2F%2Fwww.jove.com%2Fvideo%2F55295%2Fthe-rabbit-model-accelerated-atherosclerosis-methodological&psig=AOvVaw2F498qdJ37xBw-T5mFiNlr&ust=1562331763163815

Background 2

It starts with a mechanical injury

Background 3: The inside of a pipe is damage

by air bubble rupture (cavitation)

http://www.scielo.org.za/pdf/jsai

ce/v56n3/08.pdf

Background 2

How to show the evidence of the injuries in

the endothelium of the (mainly coronary)

arteries? What is the mechanism?

Background

• In hydraulic studies, the

damage in the pipelines is due

to the bursting of air bubbles.

• During diastole, bubbles

would form when the local

dynamic coronary pressure

decreases below the vapor

pressure (VP) of gases in the

blood.

• WHICH GAS?

Background

Figue 2: Bubble Formation and Implosion. Formation

of a bubble and its burst creating micro-jets

The bubbles

explode when the

dynamic coronary

pressure recovers

above the vapor

pressure.

Background

• When the bubbles explode,

the endothelial layer is

damaged and lets the LDL

particles pass through and

form the cholesterol

plaques.

Methods

• Select the coronary

angiograms with one or two

mild lesions.

• Review angiogram at 15

frames per second

– The left main (LM) .

– The proximal left anterior

descending (LAD) and

left circumflex (LCX)

– The right coronary artery

(RCA)

Methods

Figure 3.

To review the coronary

angiogram frame by frame

at 15 frames per second,

first right click and then

select Key Image option,

then use the up and down

arrows to move the

picture, one at a time.

Methods

• In the angiogram of the right

coronary artery, the lesion was

seen at the mid-segment

(arrow).

• No lesion was seen in proximal

or distal segment (WHY?)

Methods

• Laminar flow is a well

organized flow with

peripheral layer, regular

border and a pointed tip.

• It represents uniform

distribution of pressure

Methods

• Turbulent flow is

defined as coarse

mixing of blood

in white and

contrast in black

Methods

• To compare the type of flow of same patient between

the Right Coronary Artery (RCA) (with turbulent flow)

and the Left Circumflex Artery (LCX) without

turbulent flow

• (same risk factors: HTN, hyperlipidemia, etc)

Methods

• Baseline angiogram of the

left circumflex artery

without lesion

•

Methods

• The flow at the left circumflex

artery was laminar without

turbulence flow in systole and

in diastole

Methods

• In the angiogram of the right

coronary artery, multiple

plaques were seen at the mid-

segment (arrow).

• No lesion was seen in proximal

or distal segment

Methods

• The flow study of the right

coronary artery with multiple

areas of turbulence (coarse

mixing of contrast in black and

blood in white) at the

midsegment. This is the same

area with multiple plaques in

the previous slide

Methods

Methods (2nd, 3rd 3th, 6th frame)

Methods (11th, 12th, 14th, 16th frame)

Results

• In 20 coronary angiograms we see the following results:

• 80% of flow in the mid segment were turbulent and they

happened in the area with multiple lesions

• Only 10% lesion happened in the area without turbulence

CONCLUSIONS

1. TURBULENT FLOW at the mid segment of the

right, circumflex and left anterior descending artery

arteries coincide with the presence of atherosclerotic

lesions

2. This is the indirect evidence of the formation of

coronary plaques caused by mechanical injury to

the endothelium and the birth of coronary plaques.

Thank You for Your Attention