Related Experiment Video
Updated: Jul 23, 2025
Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice
Published on: April 13, 2015
Coronary microcirculatory dysfunction can be assessed by positive dicrotic wave and amplitude index on resting distal
Yoshiharu Fujimori, Satoshi Hashimoto1, Miki Takahashi1
1Department of Cardiology, Suwa Central Hospital, Tamagawa 4300, Chino, Nagano 391-8503, Japan.
Insights
High resting distal coronary pressure despite low fractional flow reserve may indicate microcirculatory dysfunction. Caffeine intake was associated with a higher amplitude index, suggesting impaired vasodilation in coronary lesions.
Area of Science:
- Cardiovascular Physiology
- Coronary Artery Disease
- Microcirculation
Background:
- Some coronary lesions exhibit high resting distal coronary pressure/aortic pressure (Pd/Pa) ratios despite low fractional flow reserve (FFR).
- This phenomenon may be linked to underlying microcirculatory dysfunction.
Purpose of the Study:
- To investigate microcirculatory dysfunction as a basal mechanism in lesions with high resting Pd/Pa and low FFR.
- To assess the impact of caffeine intake on coronary microcirculation dynamics.
Main Methods:
- Patients were divided into caffeine (222 mg) and non-caffeine groups before coronary angiography.
- Adenosine-induced Pd/Pa decrease was used to calculate the amplitude index, reflecting microcirculatory response.
- Lesions with FFR < 0.80 were categorized into high-remaining, intermediate, and low resting Pd/Pa zones.
Main Results:
- The amplitude index was significantly lower at FFR compared to resting Pd/Pa (0.44 ± 0.12 vs. 0.54 ± 0.11; P < 0.0001).
- The high-remaining Pd/Pa zone showed a higher amplitude index (0.60 ± 0.09) than the intermediate zone (0.48 ± 0.12; P < 0.005).
- Lesions in the high-remaining zone exhibited a larger positive dicrotic wave (94% vs. 30%; P < 0.005) and were more frequent in the caffeine group.
Conclusions:
- A high-remaining resting Pd/Pa with a high amplitude index suggests microcirculatory dysfunction in severe coronary stenosis.
- This dysfunction may represent insufficient arteriolar dilation in response to myocardial ischemia.
- Caffeine intake appears to be associated with impaired vasodilation in coronary lesions.
Aims:
Some lesions have high resting distal coronary pressure/aortic pressure (Pd/Pa) despite low fractional flow reserve (FFR). This study aimed to assess microcirculatory dysfunction as a possible basal mechanism.
Methods And Results:
Patients were grouped into two according to coffee intake (caffeine 222 mg) before coronary angiography. Through an adenosine-induced Pd/Pa decrease, amplitude index was calculated by dividing the difference between the highest pressure after the inflection point and the minimal diastolic pressure by the pulse pressure on the Pd waveform. In 130 coronary lesions (caffeine group, n = 69; non-caffeine group, n = 61) from 113 patients, the amplitude index through the adenosine-induced Pd/Pa decrease in all lesions was 0.54 ± 0.11 at resting Pd/Pa and 0.44 ± 0.12 at FFR (P < 0.0001). The positive dicrotic wave distribution on a maximal hyperaemia (FFRnicr)-resting Pd/Pa graph was analysed. In lesions with FFRnicr <0.80 on the FFRnicr-resting Pd/Pa graph, the resting Pd/Pa was divided into three zones based on Pd/Pa values: high-remaining, intermediate, and low. The high-remaining zone had a higher amplitude index than the intermediate zone (0.60 ± 0.09 vs. 0.48 ± 0.12; P < 0.005); the low zone lesions had no inflection point (no amplitude index). The high-remaining zone correlated with a larger positive dicrotic wave than the intermediate zone (94 vs. 30%; P < 0.005). Most lesions in the high-remaining zone corresponded to the caffeine group.
Conclusion:
In severe coronary stenosis, a high-remaining resting Pd/Pa with a high amplitude index or a positive dicrotic wave on the resting Pd waveform suggests microcirculatory dysfunction, such as insufficient arteriolar dilation reactive to myocardial ischaemia.
Registration:
UMIN000046883.
Related Concept Videos
01:25Assessment of apical radial pulse
The A-R pulse assessment involves simultaneous evaluation of the apical and radial pulses. When the apical and radial pulse rates vary, this assessment helps identify a pulse deficit.
Pre-Procedural Preparation
01:30Acute Coronary Syndrome III: Diagnostic Studies
01:21Peripheral Arterial Disease II: Clinical Manifestations and Diagnostic Evaluation
01:17Assessment of apical pulse
Assessing the apical pulse is a critical nursing procedure, particularly indicated for:
01:11Assessment of radial pulse
The radial pulse, located at the wrist, is often the preferred site for assessing peripheral pulse because of its accessibility and dependability. The process of determining the radial pulse involves several steps:
01:17Pulse amplitude and quality
A weak or absent pulse may indicate reduced cardiac output or poor left ventricular contraction, which can be signs of cardiovascular dysfunction or...