Related Experiment Video
Updated: Aug 29, 2026
Non-invasive Assessment of Microvascular and Endothelial Function
Published on: January 29, 2013
New support for clarifying the relation between ST segment resolution and microvascular function: degree of ST
1Istanbul University, Istanbul Faculty of Medicine, Department of Cardiology, Istanbul, Turkey. msezer@superonline.com
Insights
In myocardial infarction patients, worse ST segment resolution after thrombolysis correlated with higher collateral flow index (CFIp). CFIp may indicate microvascular obstruction, aiding treatment assessment.
Area of Science:
- Cardiology
- Interventional Cardiology
- Myocardial Infarction Research
Background:
- Thrombolysis is a key treatment for acute myocardial infarction.
- Assessing microvascular function post-thrombolysis is crucial for patient outcomes.
- ST segment resolution (STR) on ECG is an early indicator of reperfusion success.
Purpose of the Study:
- To examine the relationship between ST segment resolution (STR) after thrombolysis and the pressure-derived collateral flow index (CFIp).
- To assess if CFIp, measured via intracoronary pressure, reflects microvascular obstruction in recent myocardial infarction patients.
Main Methods:
- Studied 33 patients achieving TIMI grade III flow post-thrombolysis.
- Measured STR by comparing baseline and 90-minute ECGs.
- Determined CFIp using an intracoronary pressure monitoring guidewire.
Main Results:
- A significant inverse correlation (r = -0.64, p < 0.01) was found between STR and CFIp.
- Patients with good STR (≥50%) had lower mean CFIp (0.18) compared to those with poor STR (<50%) (0.27).
- Higher CFIp values were associated with worse ST segment resolution.
Conclusions:
- Despite achieving TIMI grade III flow, worse STR was linked to higher CFIp in the infarct-related artery.
- CFIp appears to quantify microvascular impedance, reflecting the degree of microvascular obstruction.
- This suggests CFIp is a valuable index for assessing microvascular function after reperfusion therapy.
Objective:
To investigate the relation between the degree of ST segment resolution (STR) after thrombolysis and the pressure derived collateral flow index (CFIp), determined using an intracoronary pressure measurement technique in patients with recent myocardial infarction.
Methods:
33 patients were studied. TIMI grade III flow was achieved in the infarct related artery by thrombolysis. A surface ECG was obtained on admission and 90 minutes later. The sum of ST segment elevations was measured by summing all leads with ST elevation on the baseline ECG and on the 90 minute ECG (after thrombolysis) and calculating the percentage recovery. The study population was divided into two groups, with good STR (> or = 50%; group 1) or poor STR (< 50%; group 2). After angiography, a fibreoptic pressure monitoring guidewire was advanced to the stenosis to be dilated. The CFIp was determined as the ratio [coronary wedge pressure - central venous pressure]/[mean aortic pressure - central venous pressure].
Results:
The mean STR on the surface ECG was 54.6% and mean (SD) CFIp was 0.25 (0.12) (range 0.10-0.41). There was an inverse correlation between the individually calculated percentage of STR and CFIp (r = -0.64, p < 0.01). The mean CFIp was lower in patients with a good STR than in those with a poor STR (0.18 (0.07) v 0.27 (0.10), p < 0.02).
Conclusions:
Although TIMI grade III flow was achieved after thrombolysis, a worse STR on the surface ECG was associated with higher CFIp measured in the infarct related artery. CFIp appears to reflect the degree of microvascular obstruction by quantifying impedance of the microvasculature.
