Hirohiko Kurihara

Early identification of impaired myocardial reperfusion with serial assessment of ST segments after percutaneous transluminal coronary angioplasty during acute myocardial infarction

To evaluate the relation between ST-segment analysis and microvascular reperfusion in patients with acute myocardial infarction (AMI), we studied 51 patients with first AMI who were successfully treated by percutaneous transluminal coronary angioplasty (PTCA). The lead showing the greatest ST-segment elevation on the 12-lead electrocardiogram (ECG) was serially investigated until 24 hours after PTCA. Successful reperfusion was determined by technetium-99m tetrofosmin single-photon emission computed tomography. Impaired reperfusion (group 1: < 4 change in the sum of the defect score from before to immediately after PTCA) was observed in 24 patients, and successful reperfusion (group 2) was observed in 27 patients. Although ST-segment elevation was reduced significantly at 30 minutes after PTCA in group 2 (2.2 +/- 1.4 to 1.7 +/- 1.3 mm, p = 0.01), there was no significant change in group 1 (1.9 +/- 1.9 to 2.4 +/- 1.7 mm). Ten of 14 patients (71%) with persistent ST-segment elevation (DeltaST > 0 mm change in ST segment from before to 30 minutes after PTCA > 0) were in group 1, whereas 23 of 37 patients (62%) with ST-segment resolution (DeltaST < or = 0) were in group 2. The sensitivity and specificity of persistent ST-segment elevation for predicting impaired microvascular reperfusion were 42% and 85%, respectively. Thus, persistent ST-segment elevation 30 minutes after primary PTCA was a highly specific electrocardiographic marker of impaired reperfusion in patients with AMI.

Early prediction of regional functional recovery in reperfused myocardium using single-injection resting quantitative electrocardiographic gated SPET

Abstract. By evaluating concordant or discordant perfusion and systolic wall thickening patterns, resting quantitative electrocardiographic (ECG) gated single-photon emission tomography (SPET) can identify various myocardial pathological conditions with different functional recovery after revascularisation therapy. However, no data are available on the ability of this methodology to predict regional functional recovery after primary percutaneous transluminal coronary angioplasty (PTCA). This study evaluated whether single-injection ECG gated SPET imaging performed at rest with 99mTc-tetrofosmin early after successful PTCA can predict recovery of regional wall motion. ECG gated SPET was performed 3 days and 3 weeks after successful PTCA in 26 patients. Regional functional parameters were automatically calculated with a 20-segment model on the day 3 image, and segments with perfusion/thickening mismatch were defined as showing preserved perfusion (>55% uptake on the end-diastolic image: mean–standard deviation of the normal value) without systolic wall thickening (mean–standard deviation of the normal value). On the third day, the regional wall motion score of 37 mismatched segments (3.8±2.1) was significantly lower than that of 41 matched normal segments (6.0±2.9), but was significantly higher than that of 108 matched abnormal segments (1.4±1.9, both P<0.01). At 3 weeks after acute MI, the regional wall motion score of mismatched segments (6.4±3.9) improved to the level of matched normal segments (7.1±3.0) and was significantly higher than that of matched abnormal segments (2.5±3.0, P<0.01). Absolute change in the regional wall motion score (3 days to 3 weeks) of mismatched segments (2.6±3.5) was significantly greater than that in the regional wall motion score of matched normal segments and matched abnormal segments (1.1±1.3 and 1.2±2.6, respectively, both P<0.05). Twenty-seven of 37 segments (73%) with perfusion/thickening mismatch showed significant improvement in regional wall motion, whereas improvement in regional wall motion was observed in 22 of 108 segments (20%) with matched abnormal segments and 6 of 41 segments (15%) with matched normal segments. Segments with perfusion/thickening mismatch had a significantly higher incidence of regional functional improvement than did matched abnormal or matched normal segments (χ2=42.3, P<0.01). Thus, by estimating both perfusion and wall thickening, single-injection resting ECG gated SPET imaging with 99mTc-tetrofosmin early after primary PTCA can predict recovery of regional wall motion after successful reperfusion.

Quantitative estimation of myocardial salvage after primary percutaneous transluminal coronary angioplasty in patients with angiographic no reflow

Angiographic Thrombolysis in Myocardial Infarction (TIMI) flow grade <2 after primary percutaneous transluminal coronary angioplasty (PTCA), defined as angiographic no reflow, predicts poor left ventricular functional recovery and survival in patients with acute myocardial infarction (MI). To determine the relation between angiographic coronary flow and myocardial salvage in the acute phase of MI, serial technetium-99m tetrofosmin imaging was performed before, immediately after and 1 month after PTCA in 117 patients. Angiographic no reflow was observed in 23 patients (20%; group 1), while 94 patients did not have angiographic no reflow (group 2). Although there was no significant difference in the defect score before PTCA between the two groups (group 1, 14.4±5.7; group 2, 13.5±4.6), the defect score immediately after PTCA in group 1 was significantly higher than that in group 2 (group 1, 12.8±5.1; group 2, 8.9±4.6; P <0.0001). A significantly smaller change in the defect score after PTCA (before minus immediately after PTCA) was observed in group 1 as compared with group 2 (group 1, 1.7±2.0; group 2, 4.5±2.9; P <0.0001). Twenty patients in group 1 (87%) had impaired myocardial reperfusion (<4 change in the defect score immediately after PTCA), as compared with 36 patients (38%) in group 2; this difference was significant (χ2=17.5, P <0.0001). The sensitivity, specificity and accuracy of angiographic no reflow in estimating impaired myocardial reperfusion were 36%, 95% and 67%, respectively. Thus, angiographic no reflow is a highly specific, although not sensitive, marker of impaired myocardial reperfusion immediately after primary PTCA.

Scintigraphic prediction of left ventricular functional recovery early after primary coronary angioplasty using single-injection quantitative electrocardiographic gated SPECT.

ObjectiveThe clinical usefulness of characterizing reperfused myocardium by perfusion/thickening assessment using electrocardiographic gated single photon emission computed tomography (SPECT) has not been investigated. We evaluated whether single-injection gated SPECT with 99mTc tetrofosmin early after primary percutaneous coronary intervention (PCI) can predict left ventricular (LV) functional recovery. MethodsGated SPECT was performed 3 days after primary PCI in 45 patients with acute myocardial infarction and revascularized segments were classified into perfusion/thickening mismatched segments, matched normal and matched abnormal segments. Gated SPECT was repeated 3 months later to evaluate the changes in LV ejection fraction (ΔLVEF). ResultsAmong 332 revascularized segments, there were 83 mismatched segments, 163 matched abnormal segments and 86 matched normal segments. In all the patients, LVEF increased significantly from 3 days to 3 months after primary PCI (52±13 to 57±14%, P<0.0001). Patients were divided into two groups according to ΔLVEF: 24 patients with LV functional recovery (ΔLVEF ≥5%) and 21 patients without LV functional recovery. The number of mismatched segments in patients with LV functional recovery was significantly greater than that in patients without (2.7±1.7 vs. 0.8±1.4, P<0.0003) despite no differences in the number of matched abnormal and matched normal segments. There was a significant correlation between ΔLVEF and the number of mismatched segments (r=0.56, P<0.0001) and LVEF at 3 months after primary PCI was related to the number of matched abnormal segments (r=−0.78, P<0.0001). ConclusionSingle-injection gated SPECT early after primary PCI can predict LV functional recovery.