Relationship between Myocardial Flow Reserve by Oxygen-15 Water Positron Emission Tomography in the Subacute Phase of Myocardial Infarction and Left Ventricular Remodeling in the Chronic Phase

Intracoronary administration of nicorandil during primary percutaneous coronary intervention: Impact on restoration of regional myocardial perfusion in reperfused myocardium during the subacute phase of myocardial infarction

Background

The impact of nicorandil as adjunctive therapy for percutaneous coronary intervention (PCI) in patients with ST-elevation myocardial infarction (STEMI) is controversial. We performed ¹⁵O-labeled water positron emission tomography (PET) to quantify regional myocardial perfusion in patients with STEMI who received nicorandil or no adjunctive therapy during PCI.

Methods

PCI was performed within 8 h after STEMI onset in 33 patients. 14 patients received intracoronary nicorandil 2 mg immediately after recanalization of the culprit lesion (Nico group). After 3–4 weeks, PET was performed in which myocardial blood flow (MBF) was measured at baseline and during adenosine triphosphate (ATP)-induced hyperemia. Myocardial vascular resistance (MVR) was calculated for all segments. Data were obtained from the reperfused (Rep) and normal segments (Cont) in each patient.

Results

In patients not given nicorandil (No-Nico group), the MBF was significantly lower in Rep than that in Cont at baseline and during hyperemia (Cont vs. Rep: 0.82 ± 0.14 vs. 0.68 ± 0.11, P = 0.001, ATP-Cont vs. ATP-Rep: 2.00 ± 0.72 vs. 1.52 ± 0.61, P = 0.017), which was restored in the Nico group (Cont vs. Rep: 0.79 ± 0.17 vs. 0.78 ± 0.20; ATP-Cont vs. ATP-Rep: 2.02 ± 0.84 vs. 1.84 ± 0.62). MVR was elevated in Rep at baseline and during hyperemia in the No-Nico group. MVR elevation in Rep was prevented in the Nico group.

Conclusions

¹⁵O-labeled water PET was feasible for segmental analysis of MBF during the subacute phase of STEMI. It revealed that intracoronary administration of nicorandil to STEMI patients who underwent PCI prevented MVR elevation and thus restored MBF in the reperfused segments to a level similar to that in the normal segments.

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¹⁵O-labeled water positron emission tomography (PET) is a tool to compare directly reperfused segments with normal segments simultaneously in each patient's hearts.

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¹⁵O-labeled water PET permits noninvasive quantitative measurement of myocardial blood flow during the subacute phase of myocardial infarction.

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¹⁵O-labeled water PET detects restoration of myocardial blood flow after intracoronary administration of nicorandil in STEMI patients.

Effect of human peripheral monocyte subsets on coronary flow reserve in infarct-related artery in patients with primary anterior acute myocardial infarction

1. In the present study, we investigated the relationships between relative levels of specific peripheral monocyte subsets and coronary flow velocity reserve (CFVR) during the subacute phase in patients with acute myocardial infarction (AMI). 2. The study was performed on 29 patients with primary anterior AMI who had been successfully treated using primary percutaneous coronary intervention. Two monocyte subsets (CD14(+)CD16(-) and CD14(+)CD16(+)) were measured by flow cytometry. Transthoracic Doppler echocardiography was used to measure CFVR on Days 4 and 7 after the onset of AMI onset. We defined DeltaCFVR as the difference in CFVR values between Days 4 and 7. The extent of myocardial salvage on Day 7 after AMI was evaluated by cardiovascular magnetic resonance (CMR) imaging as the difference between the area of myocardium at risk and the area of necrotic myocardium. 3. There was a significant negative correlation between DeltaCFVR and peak CD14(+)CD16(-) monocyte counts in AMI patients, whereas no significant association was found between CD14(+)CD16(+) monocyte counts and DeltaCFVR. There was a significant positive correlation between DeltaCFVR and the extent of myocardial salvage. 4. In conclusion, peak levels of CD14(+)CD16(-) monocytes following primary anterior AMI were closely related to the extent of microvascular injury.