Anatomy and Physiology

Question 1

What does ventricularization in catheter pressure recording indicate?

Answer 1

Ventricularization shows reduced diastolic pressure but preserved systolic pressure, often due to ostial coronary stenosis obstructing antegrade blood flow.

Question 2

What is observed in the 30-degree RAO projection regarding the LCx artery?

Answer 2

The proximal portion of the LCx artery is foreshortened, requiring caudal angulation for proper visualization.

Question 3

What percentage of the general population is left dominant regarding coronary circulation?

Answer 3

Only 10% of individuals are left dominant, but this increases to 30% in subjects with a bicuspid

Question 4

What is myocardial bridging?

Answer 4

Myocardial bridging occurs when the LAD courses beneath a muscle bundle, potentially compressing it during ventricular systole, which is usually incidental but can be associated with ischemia.

Question 5

What does the LAO caudal view show regarding the LAD?

Answer 5

The LAO caudal view projects the LAD upward from the LM, improving visualization of the LM and bifurcation.

Question 6

What is the most common coronary anomaly?

Answer 6

The most common anomaly is the origin of the LCx artery from the right sinus of Valsalva, often seen as a ‘dot’ during left ventriculography

Question 7

What is the issue with visual estimation of coronary stenoses?

Answer 7

Visual estimation is subject to variability and tends to inflate estimates of diameter stenosis by approximately 20% compared to quantitative coronary angiography.

Question 8

What is considered hemodynamically significant stenosis?

Answer 8

A 50% reduction in luminal diameter, impairing coronary flow reserve (CFR), is considered hemodynamically significant

Question 9

What is Kugel’s artery?

Answer 9

Kugel’s artery connects the proximal right or left coronary artery to the AV nodal branch of the distal RCA, supplying blood to the posterior circulation

Question 10

What does a 50% stenosis represent in terms of cross-sectional area?

Answer 10

A 50% stenosis corresponds to a 75% narrowing in cross-sectional area.

Question 11

When does coronary blood flow mainly occur?

Answer 11

Coronary blood flow predominantly occurs during diastole due to ventricular contraction, with at least 85% of flow in the LAD occurring during this phase.

Question 12

Where does the sinus node artery originate in most individuals?

Answer 12

The sinus node artery originates from the LCx artery in 40% of individuals and from the proximal RCA in 60%.

Question 13

What happens to microvascular resistance during increased oxygen demand?

Answer 13

During increased oxygen demand, microvascular resistance decreases, allowing for increased blood flow, while epicardial stenosis increases epicardial resistance.

Question 14

How does sympathetic tone affect veins and venules?

Answer 14

Increased sympathetic tone leads to venoconstriction and a decrease in venous volume, while veins generally remain in a dilated state.

Question 15

What contributes to total coronary resistance?

Answer 15

In the absence of stenoses, R3 vessels (arteriolar and intramyocardial) account for 40% to 50% of total coronary resistance.

Question 16

What is CFR and how is it influenced?

Answer 16

CFR is the ratio of maximal hyperemic blood flow to resting myocardial blood flow, influenced by hemodynamics, loading conditions, hypertrophy, and contractility.

Question 17

What is the valve of Vieussens?

Answer 17

The valve of Vieussens is located at the junction of the great cardiac vein and the coronary sinus, preventing reflux of contrast material.

Question 18

What does the Fick principle state about substance uptake?

Answer 18

According to the Fick principle, the uptake of a substance is the product of flow and the AV concentration difference of the substance.

Question 19

When should the Hakki equation not be used?

Answer 19

The Hakki equation should not be used to estimate valve area at extremes of heart rate (<60 bpm or >100 bpm) due to potential inaccuracies

Question 20

What is instantaneous wave-free ratio (iFR)?

Answer 20

iFR measures the hemodynamic significance of coronary artery stenosis during mid to late diastole, without requiring hyperemia.

Question 21

What is the typical oxygen saturation in coronary venous blood at rest?

Answer 21

At rest, transmyocardial oxygen extraction is nearly maximal, with coronary venous oxygen saturations typically between 25% to 35%.

Question 22

What is the normal value of FFR?

Answer 22

FFR has a normal value of 1 for every patient and every coronary artery, demonstrating high reproducibility and low variability.

Question 23

What factors influence the clinical significance of an anomalous coronary artery?

Answer 23

The course of an anomalous coronary artery is crucial in determining whether it is benign or associated with complications such as angina or sudden death.