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Observation of the ischemic cascade in humans using contrast echocardiography during dobutamine stress
Eiichi Hyodo1, Takashi Muro, Takeshi Hozumi
1Departments of Internal Medicine and Cardiology, Osaka City University School of Medicine, Osaka, Japan.
Insights
This study demonstrates the clinical occurrence of the ischemic cascade in patients with coronary artery disease. Myocardial perfusion abnormalities precede wall motion abnormalities during dobutamine stress echocardiography.
Area of Science:
- Cardiology
- Echocardiography
- Ischemic Heart Disease
Background:
- The ischemic cascade, a sequence of functional and mechanical changes during myocardial ischemia, is a key concept in cardiology.
- Previous research has primarily focused on experimental models to understand this cascade.
- Clinical validation of the ischemic cascade's sequence is essential for accurate diagnosis and treatment.
Purpose of the Study:
- To investigate the clinical applicability of the ischemic cascade hypothesis.
- To determine if myocardial perfusion abnormalities (MPA) precede wall motion abnormalities (WMA) in patients with suspected coronary artery disease.
Main Methods:
- Fifty-three patients underwent dobutamine stress echocardiography with Levovist contrast.
- Myocardial perfusion and wall motion were assessed simultaneously.
- Time-intensity data analysis (Y=A(1-e(-)(beta)(t))) quantified myocardial opacification and derived the rate of increase (beta).
- Coronary angiography identified significant stenosis (>50%) in the left anterior descending artery in 25 patients (Group II), while 25 served as controls (Group I).
Main Results:
- Significant differences in the stress/rest beta ratio were observed between groups at low-dose (p<0.05) and high-dose dobutamine (p<0.001).
- Wall motion score differences were significant only at high-dose dobutamine.
- In patients with coronary stenosis (Group II), MPA preceded WMA in 12 patients, occurred simultaneously in 12, and neither was observed in 1.
Conclusions:
- This study provides clinical evidence supporting the ischemic cascade.
- Contrast echocardiography during dobutamine stress effectively demonstrates that myocardial perfusion abnormalities precede wall motion abnormalities in patients with coronary artery stenosis.
- These findings validate the sequence of events in the ischemic cascade in a clinical setting.
Abstract:
Experimental studies have postulated the ischemic cascade and the present study was designed to elucidate whether it can be observed in the clinical setting. Fifty-three patients suspected of having coronary artery disease were studied. Myocardial perfusion abnormalities (MPA) and wall motion abnormalities (WMA) were assessed simultaneously by infusion of Levovist during dobutamine stress echocardiography. Time - intensity data of myocardial opacification were fitted for Y=A (1-e(-)(beta) (t)) from which the rate of increase (beta) of intensity were derived both at rest and during stress. Wall motion was also given a score. Bright opacification was observed in 50 patients: 25 showed significant stenosis (>50%) in the left anterior descending artery (group II) on coronary angiography and 25 did not (group I). Significant differences were found in the beta ratio (stress/rest) between the 2 groups at a low-dose (2.0+/-0.3 vs 1.5+/-0.5, p<0.05) and at a high-dose of dobutamine (2.7+/-1.0 vs 1.1+/-0.5, p<0.001), whereas the wall motion score differed only at a high-dose. Of the 25 patients in group II, MPA preceded WMA in 12, both occurred at the same stage in 12, and neither MPA nor WMA was seen in 1. These data prove the ischemic cascade clinically, using contrast echocardiography, by demonstrating that MPA precede WMA during dobutamine stress in patients with coronary stenosis.