Kengo Hatada

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.

Pericardial effusion after primary percutaneous transluminal coronary angioplasty in first Q-wave acute myocardial infarction

To evaluate the incidence and clinical significance of infarction-associated pericardial effusion in patients with successful primary percutaneous transluminal coronary angioplasty, we studied 214 consecutive patients with a first Q-wave acute myocardial infarction. Based on 9 clinical variables, multivariate analysis was performed to determine the important variables related to the occurrence of pericardial effusion. Pericardial effusion was detected by echocardiography in 45 patients (21%); pericardial rub (p <0.001), number of advanced asynergic segments (p <0.001), ventricular aneurysmal motion (p = 0.03), and pulmonary capillary wedge pressure (p = 0.04) were found to be the important variables related to pericardial effusion. Among 45 patients with pericardial effusion, 29 patients with no pericardial rub had significantly higher pulmonary capillary wedge pressure than those with pericardial rub, whereas 16 patients with pericardial rub had a higher incidence of angiographic no reflow and ventricular aneurysmal motion than those without pericardial rub. Patients with pericardial effusion and a pericardial rub had a higher mortality rate than those without pericardial effusion (19% vs 3%; p = 0.02). Thus, pericardial effusion is still a relatively common clinical finding after primary percutaneous transluminal coronary angioplasty, and those with pericardial effusion and a pericardial rub were associated with more severe transmural myocardial damage and higher in-hospital mortality.

Iodine 123-metaiodobenzylguanidine imaging reflect generalized sympathetic activation in patients with left ventricular dysfunction

Background:  Iodine 123‐metaiodobenzylguanidine (MIBG) imaging has been used to assess cardiac sympathetic nerve abnormalities. To determine the role of MIBG imaging as a measure of generalized sympathetic nerve activity, MIBG imaging was evaluated with muscle sympathetic nerve activity (MSNA) and plasma norepinephrine (noradrenaline) level in patients with old myocardial infarction.

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.

Coronary artery diameter and left ventricular function in patients on maintenance hemodialysis treatment: comparison between diabetic and nondiabetic patients.

Background/Aims: This study examined the role of diabetes mellitus on determining left ventricular function by evaluating coronary artery diameter in patients with end-stage renal disease on maintenance hemodialysis treatment. Methods: We studied 12 diabetic and 12 nondiabetic patients on maintenance hemodialysis treatment without significant stenoses of the major epicardial coronary arteries. Patients were matched for age, sex distribution, duration of dialysis and incidence of major coronary risk factors. Left ventricular wall thickness (septal and posterior walls) and left ventricular diameter (end-diastolic and systolic phases), were measured by echocardiography. Hemodynamic measurements and coronary angiography were performed on the day of hemodialysis and coronary artery diameter at the proximal and mid portion of three major coronary arteries were measured using the computed densitometry method. Results: Right and left anterior descending and circumflex coronary artery diameters were all significantly smaller and the frequency of coronary artery calcification was higher in diabetic (58%) compared to nondiabetic (8%) patients. Although there were no significant differences in left ventricular wall thickness, left ventricular diameter, mean right atrial pressure and cardiac index between the two groups, left ventricular end-diastolic pressure was significantly higher in diabetic (22 ± 9 mm Hg) compared to nondiabetic patients (14 ± 5 mm Hg). Conclusion: Despite that there were no significant stenoses of the major epicardial coronary arteries, diffuse luminal narrowing of the epicardial coronary arteries in diabetic patients on maintenance hemodialysis treatment was associated with increased left ventricular end-diastolic pressure.

Non-invasive detection of ischemic left ventricular dysfunction using rest gated SPECT: expectation of simultaneous evaluation of both myocardial perfusion and wall motion abnormality

ObjectiveAlthough the accurate detection of ischemic etiology is important in the management of patients with severe left ventricular (LV) dysfunction, it is difficult to determine using a non-invasive strategy. The present study investigates whether perfusion and regional functional abnormalities identified by quantitative electrocardiographic gated single-photon emission computed tomography (QGS) at rest can detect ischemic LV dysfunction in patients with severe LV dysfunction.MethodsRest QGS with 99mTc-tetrofosmin was performed on 54 consecutive patients with LV ejection fraction of ≤40%. Ischemic LV dysfunction (n = 32) was defined according to the established standard. Regional perfusion and wall motion were calculated using a 14-segment model (six mid-ventricular and eight apical segments) and compared with a normal control group.ResultsThe numbers of reduced [mean −1 standard deviation (SD) of normal individuals] and severely reduced (mean −2 SD) wall motion segments were similar between patients with ischemic and non-ischemic LV dysfunction (13.5 ± 1.1 vs. 13.6 ± 0.9 and 10.6 ± 2.0 vs. 9.9 ± 3.0 segments, respectively). The number of hypoperfused (mean −1 SD) segments was significantly greater in patients with ischemic LV dysfunction than in those with non-ischemic LV dysfunction (9.3 ± 3.8 vs. 2.0 ± 2.8 segments, P < 0.0001). The analysis of the receiver operating characteristics showed that a cut-off value of 4 hypoperfused segments among 14 segments provided the best separation between ischemic and non-ischemic LV dysfunction (sensitivity = 88% and specificity = 91%). Furthermore, patients with non-ischemic LV dysfunction had no severely hypoperfused (mean −2 SD) segments in any of the segments, whereas patients with ischemic LV dysfunction had 4.4 ± 0.2 segments.ConclusionsThe QGS strategy at rest can accurately differentiate patients with ischemic LV dysfunction from those with severe LV dysfunction by simultaneous regional evaluation of wall motion and myocardial perfusion.

Accuracy of technetium-99m tetrofosmin myocardial perfusion imaging in the detection of spontaneous recanalization in patients with acute anterior myocardial infarction

To avoid the haemorrhagic risk of unnecessary thrombolysis in acute myocardial infarction (MI), early and precise diagnosis of spontaneous recanalization (SR) of the infarct-related artery is required. To clarify the accuracy of technetium-99m tetrofosmin myocardial single-photon emission tomography (SPET) in the detection of SR in patients with acute anterior MI, electrocardiography (ECG), echocardiography and 99mTc-tetrofosmin SPET imaging were performed in 49 patients with acute anterior MI before emergency coronary angiography. Defect score was calculated as the sum of the perfusion defects of each segment: from 3 (complete defect) to 0 (normal perfusion). Echocardiographic asynergic score (the sum of asynergic grades) and the greatest ST elevation of the 12-lead ECG on admission were also measured. SR was defined as Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow on emergency coronary angiography. Defect score in 11 patients with SR (9.2±3.7) was significantly lower than that in 38 patients without SR (18.5±5.0) (P<0.001), whereas there were no significant differences in asynergic score and ST elevation between the two groups. From the receiver operating characteristic curves, the optimal cut-off points of defect score, asynergic score and ST elevation for the detection of SR were calculated to be 12, 13 and 3.5, respectively. The sensitivity and specificity of the scintigraphic defect score (91% and 89%) were significantly higher than those of the asynergic score (64% and 68%) and ST elevation (73% and 71%). Thus, 99mTc-tetrofosmin SPET imaging on admission is a very accurate method for the detection of SR in patients with acute anterior MI.

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.

Combined analysis of multislice computed tomography coronary angiography and stress-rest myocardial perfusion imaging in detecting patients with significant proximal coronary artery stenosis.

ObjectiveMultislice computed tomography (MSCT) coronary angiography (CAG) is limited in detecting significant coronary artery stenosis because of its low specificity and positive predictive value. Stress–rest myocardial perfusion imaging (MPI) can detect myocardial ischemia. The aim of this study was to evaluate the diagnostic accuracy of detecting patients with proximal coronary artery disease for coronary intervention by combined analysis of MSCT-CAG and MPI. MethodsMSCT-CAG, MPI, and CAG were performed in 125 patients with chest pain suggestive of coronary artery disease. A significant proximal coronary artery stenosis was defined as ≥75% stenosis by MSCT and CAG. Myocardial ischemia was defined as reversible defect by MPI. Patients were defined as having coronary artery disease with a significant coronary stenosis by CAG. ResultsSeventy-four patients had a significant proximal coronary artery stenosis by MSCT. Of the 74 patients with a coronary artery stenosis by MSCT, 50 (67.6%) patients had a significant proximal coronary artery stenosis by CAG. In contrast, 50 (98.0%) of 51 patients without coronary artery stenosis by MSCT did not have coronary artery disease. In detecting patients with proximal coronary artery disease, combined analysis of MSCT and MPI showed a considerable improvement in specificity (94.6 vs. 67.6%, P = 0.0001) and positive predictive value (92.3 vs. 67.6%, P = 0.01) without significant changes in sensitivity (94.1 vs. 98.0%) and negative predictive value (95.9 vs. 98.0%) compared with MSCT alone. ConclusionCombined analysis of MSCT-CAG and MPI can accurately detect patients with proximal coronary artery disease.

Cardiovascular response to combined static-dynamic exercise of patients with myocardial infarction.

BackgroundGraded dynamic exercise‐stress testing of patients with acute myocardial infarction prior to discharge from hospital has an important diagnostic and prognostic implication. Although many daily tasks involve combinations of static and dynamic exercise, little is known about cardiovascular responses during combined static–dynamic exercise. ObjectiveTo determine the difference between cardiovascular responses during two types of combined static–dynamic exercise (a 10 kg weight in one hand, and a 10 kg weight bearing on the shoulder). MethodsWe studied 27 male patients who had recently suffered myocardial infarction using ear densitography. The patients were divided into two groups : group 1 was comprised of 14 patients with resting left ventricular end‐diastolic volumes ≥140 ml, and group 2 was comprised of 13 patients with left ventricular end‐diastolic volumes <140 ml. ResultsFor eight patients in group 1 we detected positive electrocardiographic changes during one‐hand weight‐carrying exercise, but for none of these patients was there an electrocardiographic change during weight‐bearing exercise. All the patients in group 2 completed both types of exercise without significant ST‐segment change. Although there were no significant differences between values of any of the indices measured for the two groups during weight‐bearing exercise, patients in group 1 had significantly shorter diastolic times/min (21.8±2.1 versus 25.1±2.4 s/min, P  < 0.01) during one‐hand weight carrying. ConclusionsIn addition to decrease in subendocardial coronary blood flow associated with increase in left ventricular end‐diastolic volume, shortening of diastolic perfusion time during one‐hand weight‐carrying exercise for patients in group 1 can potentially contribute to subendocardial ischemia, which was favorably altered by bearing a weight on the shoulder.