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Pressure-derived collateral flow index as a parameter of microvascular dysfunction in acute myocardial infarction
1Division of Cardiology, Sakurabashi Watanabe Hospital, Osaka, Japan.
Insights
The pressure-derived collateral flow index (CFIp) in acute myocardial infarction (AMI) does not reflect collateral function but indicates microvascular dysfunction. Higher CFIp correlates with worse functional recovery, serving as a useful predictor of clinical outcomes.
Area of Science:
- Cardiology
- Cardiovascular Research
- Interventional Cardiology
Background:
- The pressure-derived collateral flow index (CFIp) is linked to ischemia severity in non-infarcted hearts.
- Its role in acute myocardial infarction (AMI) with or without no-reflow remains unclear.
Purpose of the Study:
- To investigate the implications of CFIp in patients experiencing AMI.
- To determine if CFIp reflects collateral function or microvascular dysfunction in AMI.
Main Methods:
- 48 patients with first AMI underwent percutaneous transluminal coronary angioplasty (PTCA).
- CFIp was calculated using aortic pressure, central venous pressure, and coronary wedge pressure.
- Myocardial contrast echocardiography (MCE) assessed perfusion; left ventriculograms measured regional wall motion.
Main Results:
- CFIp did not differ across angiographic collateral grades.
- CFIp was significantly higher in patients with MCE no-reflow compared to reflow (p < 0.01).
- Higher CFIp correlated inversely with functional improvement (r = 0.56, p < 0.01).
Conclusions:
- CFIp in AMI likely indicates microvascular dysfunction rather than collateral function.
- Elevated CFIp is associated with poorer myocardial functional recovery post-AMI.
- CFIp offers a simple, valuable estimate of clinical outcomes in AMI patients.
Objectives:
The goal of this study was to examine the implications of the pressure-derived collateral flow index (CFIp) in acute myocardial infarction (AMI).
Background:
Higher CFIp is associated with less severe myocardial ischemia during angioplasty in the non-infarcted heart. It remains unknown whether CFIp also identifies collateral function in AMI patients with and without no-reflow phenomenon.
Methods:
The study population included 48 patients with a first AMI. After successful percutaneous transluminal coronary angioplasty (PTCA) stent, we measured mean aortic pressure (Pa), central venous pressure (Pv) and coronary wedge pressure (Pcw) of the infarct-related artery to calculate: CFIp = (Pcw - Pv)/(Pa - Pv). Myocardial contrast echocardiography (MCE) was performed with the intracoronary injection of microbubbles to assess myocardial perfusion. Left ventriculograms at days 1 and 28 were provided for the measurement of the regional wall motion (RWM, SD/chord).
Results:
There was no difference in CFIp among subsets based on angiographic collateral grades (grade 0, 1, 2, 3; 0.28 +/- 0.07, 0.27 +/- 0.09, 0.27 +/- 0.08, 0.23 +/- 0.08, p = NS). The CFIp was significantly higher in patients with MCE no-reflow (n = 16) than in those with MCE reflow (n = 32) (0.34 +/- 0.07 vs. 0.23 +/- 0.06, p < 0.01). There was a significant inverse correlation between the extent of functional improvement (DeltaRWM[28 d-1 d]) and CFIp (r = 0.56, p < 0.01), implying that higher CFIp is associated with worse functional improvement.
Conclusions:
In AMI, CFIp is unlikely to reflect collateral function but seems to increase with the severity of microvascular dysfunction. Because higher CFIp was associated with poorer functional recovery, it provides a simple and useful estimate of clinical outcomes in AMI.