Instantaneous wave-free ratio

Error creating thumbnail:

# Instantaneous Wave-Free Ratio

The Instantaneous Wave-Free Ratio (iFR) is a diagnostic tool used in the field of cardiology to assess the severity of coronary artery stenosis. It is a non-hyperemic pressure ratio that measures the pressure difference across a coronary artery lesion during a specific period of the cardiac cycle when the heart is at rest.

Background

Coronary artery disease is a condition characterized by the narrowing of the coronary arteries due to the buildup of atherosclerotic plaques. This can lead to reduced blood flow to the heart muscle and result in chest pain or myocardial infarction. Traditionally, the severity of coronary stenosis has been assessed using Fractional Flow Reserve (FFR), which requires the use of a hyperemic agent to induce maximum blood flow.

Principle

The iFR is calculated during the wave-free period of diastole, a phase in the cardiac cycle when the resistance in the microcirculation is naturally minimized. This allows for the assessment of the pressure gradient across a coronary lesion without the need for pharmacological agents. The iFR is expressed as a ratio of the distal coronary pressure to the aortic pressure.

Clinical Use

The iFR is used to guide percutaneous coronary intervention (PCI) decisions. It provides a physiological assessment of coronary stenosis, helping clinicians determine whether a particular lesion is likely to benefit from stenting. An iFR value below a certain threshold indicates that the lesion is hemodynamically significant and may require intervention.

Advantages

One of the main advantages of iFR over FFR is that it does not require the administration of hyperemic agents, which can cause discomfort and side effects in patients. This makes the procedure quicker and more comfortable for patients. Additionally, iFR can be measured more rapidly, reducing the overall time of the procedure.

Limitations

While iFR offers several advantages, it may not be suitable for all patients or lesions. Certain anatomical or physiological conditions may affect the accuracy of iFR measurements. Clinicians must consider these factors when interpreting iFR results.

Related Pages

• Fractional Flow Reserve
• Coronary Artery Disease
• Percutaneous Coronary Intervention
• Atherosclerosis

Cardiovascular disease A-Z

Most common cardiac diseases

• Cardiac arrhythmia‎
• Cardiogenetic disorders‎
• Cardiomegaly‎
• Cardiomyopathy‎
• Cardiopulmonary resuscitation‎
• Chronic rheumatic heart diseases‎
• Congenital heart defects‎
• Heart neoplasia‎
• Ischemic heart diseases‎
• Pericardial disorders
• Syndromes affecting the heart‎
• Valvular heart disease‎

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

• Accelerated idioventricular rhythm
• Acute decompensated heart failure
• Arteriosclerotic heart disease
• Athletic heart syndrome
• Atrial flutter
• Atrioventricular fistula
• Cardiovascular disease in Australia
• Autoimmune heart disease

B

• Brown atrophy of the heart

C

• Ebb Cade
• Cardiac allograft vasculopathy
• Cardiac amyloidosis
• Cardiac asthma
• Cardiac tamponade
• Cardiogenic shock
• Cardiogeriatrics
• Cardiorenal syndrome
• Cardiotoxicity
• Carditis
• Coronary artery aneurysm
• Coronary artery anomaly
• Coronary artery disease
• Spontaneous coronary artery dissection
• Coronary artery ectasia
• Coronary occlusion
• Coronary steal
• Coronary thrombosis
• Coronary vasospasm
• Cœur en sabot
• Coxsackievirus-induced cardiomyopathy

D

• Duke Treadmill Score
• Duroziez's disease

E

• Eisenmenger's syndrome
• Embryocardia
• Endocardial fibroelastosis
• Eosinophilic myocarditis

H

• Heart attack
• Heart failure
• Heart failure with preserved ejection fraction
• Heart to Heart (1949 film)
• High-output heart failure
• Hyperdynamic precordium

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

I

• Idiopathic giant-cell myocarditis
• Interventricular dyssynchrony
• Intraventricular dyssynchrony
• Isolated atrial amyloidosis

K

• Keshan disease

L

• Loeffler endocarditis

M

• Mydicar
• Myocardial bridge
• Myocardial disarray
• Myocardial rupture
• Myocardial scarring
• Myocardial stunning
• Myocarditis

N

• Nonbacterial thrombotic endocarditis

O

• OLR1
• Ostial disease

P

• Papillary fibroelastoma
• Pathophysiology of heart failure
• Postpericardiotomy syndrome
• Pulmonary vein stenosis

R

• Right axis deviation
• Roemheld syndrome

S

• Saturated fat and cardiovascular disease
• SCAR-Fc
• Shone's syndrome
• Strain pattern
• Subacute bacterial endocarditis
• Sudden cardiac death of athletes

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

T

• Traumatic cardiac arrest

V

• Ventricular aneurysm
• Vibroacoustic disease
• Viral cardiomyopathy

W

• Waon therapy