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Recovery of myocardial function. The ultimate target of coronary revascularization
O Alfieri1, G La Canna, R Giubbini
1Division of Cardiac Surgery, Civic Hospital, Brescia, Italy.
Insights
The dobutamine echocardiography test effectively predicts myocardial recovery after revascularization, identifying viable hibernating myocardium with high accuracy. This method aids in assessing patients with depressed left ventricular function before surgery.
Area of Science:
- Cardiology
- Medical Imaging
- Cardiac Surgery
Background:
- Assessing myocardial viability is crucial for patients with chronic left ventricular dysfunction undergoing coronary revascularization.
- Hibernating myocardium, or viable akinetic segments, presents a target for improving cardiac function post-surgery.
Purpose of the Study:
- To evaluate the efficacy of dobutamine infusion echocardiography in identifying viable akinetic myocardium.
- To compare dobutamine stress echocardiography with Thallium-201 (TI-201) redistribution for predicting postoperative recovery of myocardial function.
Main Methods:
- Dobutamine infusion echocardiography was used in 14 patients to assess contractile reserve in akinetic segments.
- Thallium-201 (TI-201) rest redistribution imaging was performed to evaluate myocardial viability.
- Wall motion response to dobutamine and TI-201 findings were correlated with early and late postoperative functional recovery.
Main Results:
- Dobutamine echocardiography showed high sensitivity (91.3%) and specificity (78.1%) in predicting immediate postoperative improvement.
- TI-201 rest redistribution demonstrated high sensitivity (93.0%) but lower specificity (43.7%) for early recovery, improving to 64.0% with late recovery.
- A positive echo-dobutamine test indicated immediate functional recovery and suggested low operative risk.
Conclusions:
- Dobutamine echocardiography is a reliable method for identifying hibernating myocardium and predicting early functional recovery after revascularization.
- TI-201 imaging identifies myocardial viability but is less specific for predicting early functional recovery compared to dobutamine stress echocardiography.
- The echo-dobutamine test is valuable for surgical decision-making in patients with compromised left ventricular function.
Abstract:
Recovery of myocardial contraction represents an important target of coronary revascularization and the preoperative recognition of viable akinetic (hibernating) myocardium is a crucial point of the preoperative investigation of patients with chronically depressed left ventricular function. In 14 patients dobutamine infusion during echocardiography was utilized to evoke the contractile reserve retained by viable akinetic segments. Redistribution of thallium(TI)-201 after the rest injection was also used to assess the viability of akinetic areas. The wall motion response to dobutamine infusion predicted immediate postoperative improvement in 85 of 93 segments (sensitivity 91.3%) and identified 25 of the 32 segments which did not exhibit early postoperative improvement (specificity 78.1%). Rest redistribution of TI-201 demonstrated high sensitivity (93.0%) but low specificity (43.7%) for predicting the early recovery of regional wall motion. When late recovery was also considered, the specificity of this method increased to 64.0%. Rest distribution of TI-201 identifies viability which is not necessarily associated with the early recovery of function postoperatively. When the echo-dobutamine test is positive, on the other hand, the recovery of function usually occurs immediately after revascularization and the operative risk is expected to be low even in the presence of severely compromised left ventricular function.