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Detecting myocardial salvage after primary PTCA: early myocardial contrast echocardiography versus delayed sestamibi
R Sciagrà1, L Bolognese, D Rovai
1Department of Clinical Physiopathology, University of Florence, Italy.
Insights
Myocardial contrast echocardiography (MCE) immediately after primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI) has limited value. Sestamibi SPECT is a reliable method for predicting functional recovery and identifying myocardial stunning.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Interventional Cardiology
Background:
- Assessing myocardial salvage after primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI) is crucial but variable.
- Predicting tissue salvage and functional recovery based on vessel patency or early wall motion is unreliable.
Purpose of the Study:
- To evaluate myocardial contrast echocardiography (MCE) for assessing microvascular integrity and predicting myocardial salvage and functional recovery after primary PTCA.
- To compare the diagnostic performance of MCE with sestamibi perfusion imaging.
Main Methods:
- Twenty-six AMI patients underwent MCE before and after primary PTCA.
- Wall motion was assessed using echocardiography, and sestamibi SPECT was performed within one week.
- Myocardial viability was defined by MCE (contrast enhancement) and sestamibi SPECT (tracer activity).
Main Results:
- MCE showed high sensitivity (91%) but low specificity (14%) for detecting viable myocardium.
- Sestamibi SPECT demonstrated lower sensitivity (68%) but significantly higher specificity (75%) and overall predictive accuracy (88%) compared to MCE.
- On a patient basis, SPECT was more specific (79% vs. 21%) and accurate (88% vs. 50%) than MCE.
Conclusions:
- Immediate MCE assessment of microvascular integrity after primary PTCA has limited diagnostic value for predicting myocardial salvage.
- Resting sestamibi SPECT, performed later, is a reliable method for identifying myocardial stunning and predicting functional recovery.
Unlabelled:
The extent of myocardial salvage after primary percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI) is variable and cannot be predicted on the basis of either vessel patency or early regional wall motion assessment. The aim of this study was to evaluate the reliability of microvascular integrity, as shown by myocardial contrast echocardiography (MCE), as an indicator of tissue salvage and a predictor of late functional recovery, and to compare MCE with the quantification of tracer activity in sestamibi perfusion imaging.
Methods:
Twenty-six patients with AMI who received successful treatment with primary PTCA were examined with MCE during cardiac catheterization immediately before and after vessel recanalization. Myocardial contrast effect was scored as 0 (absent), 0.5 (partial) or 1 (normal). Wall motion was assessed by two-dimensional echocardiography on admission and 1 mo later with a 16-segment model and 4-point score. Resting sestamibi SPECT was collected within 1 wk after AMI. The risk area was defined by MCE as the sum of the segments with no perfusion (score 0) before PTCA. Myocardial viability was defined by MCE as an increase in contrast score in the same segments after PTCA and by sestamibi SPECT as a preserved tracer activity (>60% of peak activity). The functional recovery after 1 mo detected by two-dimensional echocardiography was the reference standard for viability.
Results:
A total of 50 segments showed perfusion defects before PTCA (risk area). Immediately after PTCA, the MCE score increased in 44 of 50 segments, whereas sestamibi SPECT showed preserved activity in 22 of 50 segments. After 1 mo, the wall motion score decreased in 22 of 50 segments (viable segments) and was unchanged in the remaining 28 segments. Thus, MCE showed a sensitivity of 91% and a specificity of 14% in detecting viable myocardium, whereas sestamibi SPECT showed a lower sensitivity (68%) but a significantly higher specificity (75%; P < 0.00001). The positive predictive values were 45% and 68% for MCE and SPECT (P < 0.005), respectively, and the negative predictive values were 67% and 71%, respectively. On a patient basis, SPECT was more specific (79% versus 21%; P < 0.01) and showed a higher overall predictive accuracy (88% versus 50%; P < 0.01) than MCE.
Conclusion:
The demonstration of microvascular integrity by MCE performed immediately after primary PTCA has a limited diagnostic value in predicting salvaged myocardium. Conversely, tracer activity quantification in resting sestamibi SPECT performed in a later stage is confirmed to be a reliable approach for recognizing myocardial stunning and predicting functional recovery.