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[MIBI-echocardiography with dobutamine: Significance of changes of contractility in patients with changes in
M M de la Torre1, J A San Román, I Vilacosta
1Servicio de Cardiología, Hospital Universitario, Valladolid.
Insights
In patients with coronary artery disease, wall motion abnormalities during dobutamine stress indicate more severe perfusion defects on MIBI-SPECT imaging, even without prior heart attack. This helps identify patients needing closer monitoring.
Area of Science:
- Cardiology
- Nuclear Medicine
- Diagnostic Imaging
Background:
- Coronary artery disease (CAD) can cause perfusion defects and contractility abnormalities.
- Perfusion defects without contractility issues may indicate absent or mild ischemia.
Purpose of the Study:
- To compare clinical characteristics, hemodynamic response, and perfusion defect severity in CAD patients with and without wall motion abnormalities during dobutamine infusion.
- To evaluate the significance of wall motion abnormalities in dobutamine stress MIBI-SPECT.
Main Methods:
- Eighty-two patients with significant CAD (angiographically proven, no prior MI) underwent dobutamine infusion stress.
- Myocardial perfusion imaging using MIBI-SPECT was performed at peak stress and rest.
- Perfusion scores were calculated to quantify defect severity.
Main Results:
- Among 73 patients with perfusion defects, 59 had positive stress echocardiograms (Group A) and 14 had negative (Group B).
- Group A had more hypertensive patients and a higher incidence of electrical abnormalities and angina.
- Perfusion defects were similarly extensive but more severe in Group A, indicated by lower perfusion scores.
Conclusions:
- Wall motion abnormalities during dobutamine stress in CAD patients with perfusion defects are associated with more severe perfusion abnormalities on MIBI-SPECT.
- This finding aids in stratifying patients with coronary artery disease based on stress imaging results.
Background And Objectives:
In the presence of coronary artery disease and with an appropriate stressor, perfusion defects precede contractility abnormalities. Perfusion defects without contractility abnormalities may be due to the absence of ischemia or mild ischemia. Our purpose has been to compare the clinical characteristics, hemodynamic response and severity of perfusion defects in patients with coronary artery disease and perfusion defects with and without wall motion abnormalities during dobutamine infusion.
Patients And Methods:
Eighty two patients with significant coronary artery disease demonstrated by angiography without previous myocardial infarction underwent dobutamine infusion (up to 40 mg/kg/min). Atropine was given when necessary. Stress scientigraphic MIBI-SPECT images were acquired 1 hour after peak stress and rest studies were obtained 24 hours after stress testing. The perfusion score was calculated by dividing the total uptake score between the number of segments affected.
Results:
Among the 73 patients with perfusion defects, stress echocardiography was positive in 59 (Group A) and was negative in the remaining 14 (Group B). There were more hypertensive patients in Group A (33 vs 4; p = 0.04). There was no significant difference between the two groups with respect to other clinical characteristics. The peak rate-pressure product was similar in both groups (18.520 +/- 5.691 vs 18.680 +/- 5.329; p = NS). The development of electric abnormalities and angina was more common in Group A (42 vs 3, p < 0.001 and 33 vs 1; p < 0.001). Perfusion defects were not more extensive in Group A (abnormal segments 2.15 vs 2.21; p = NS) but they were more severe (segments with severe uptake reduction or no uptake 1.10 vs 0.28; p < 0.05; perfusion score 2.62 vs 2.21; p < 0.05).
Conclusion:
In patients with severe coronary artery disease and perfusion defects during dobutamine-MIBI-SPECT, the presence of wall motion abnormalities defines patients with more severe perfusion defects.