Hidetaka Nishina

Automatic Global and Regional Phase Analysis from Gated Myocardial Perfusion SPECT Imaging: Application to the Characterization of Ventricular Contraction in Patients with Left Bundle Branch Block

Although many patients with heart failure benefit from cardiac resynchronization therapy (CRT), predicting which patients will respond to CRT remains challenging. Recent evidence suggests that the analysis of mechanical dyssynchrony using gated myocardial perfusion SPECT (MPS) may be an effective tool. The aim of this study was to evaluate global and regional gated MPS dyssynchrony measurements by comparing parameters obtained from patients with a low likelihood (LLk) of conduction abnormalities and coronary artery disease and patients with left bundle branch block (LBBB). Methods: A total of 86 consecutive patients with LLk and 72 consecutive patients with LBBB, all without prior myocardial infarction or sternotomy, were studied using gated MPS. Global (histogram SD [σ], bandwidth [β], and entropy [ε]) and regional (wall- and segment-based differences of means [ΔμW and ΔμS, respectively] or modes [ΔMW and ΔMS, respectively]) dyssynchrony measures were calculated by Fourier harmonic phase-angle analysis of local myocardial count variations over the cardiac cycle for each patient, and then unpaired t tests were used to determine which parameters were sex-specific and how well they discriminated between the LLk and LBBB populations. Receiver-operating-characteristic analysis was also performed to calculate the area under the curve (AUC), sensitivity (Ss), specificity (Sp), and optimal threshold (Th). Results: Global parameters were found to be sex-specific, whereas regional differences were sex-independent. All parameters studied showed statistically significant differences between the groups (all global, P < 0.05; all regional, P < 0.0001). Receiver-operating-characteristic analysis yielded higher AUC, Ss, and Sp for ε and regional parameters (ε: AUC = 0.95/0.96, Ss = 94%/88%, Sp = 89%/91%, and Th = 53.9%/60.6% for women/men; ΔμW: AUC = 0.93, Ss = 88%, Sp = 86%, and Th = 10.5°; ΔμS: AUC = 0.94, Ss = 90%, Sp = 94%, and Th = 9.2°; ΔMW: AUC = 0.95, Ss = 90%, Sp = 94%, and Th = 15°; and ΔMS: AUC = 0.95, Ss = 88%, Sp = 90%, and Th = 10.5°) than for global parameters (σ: AUC = 0.75/0.67, Ss = 81%/66%, Sp = 63%/64%, and Th = 16.5°/22.2° for women/men; β: AUC = 0.80/0.72, Ss = 71%/71%, Sp = 79%/64%, and Th = 69°/81° for women/men). Conclusion: The computed parameters all discriminate effectively between LLk and LBBB populations. Measurements that are less dependent on the shape of the phase-angle distribution histogram provided higher sensitivity and specificity for this purpose. Further study is needed to evaluate these parameters for the purpose of predicting response to CRT.

Association of contrast-induced acute kidney injury with long-term cardiovascular events in acute coronary syndrome patients with chronic kidney disease undergoing emergent percutaneous coronary intervention☆

BACKGROUND The association between contrast-induced acute kidney injury (CI-AKI) and chronic kidney disease (CKD) in patients with acute coronary syndrome (ACS) treated with percutaneous coronary intervention (PCI) has not been fully reported. We evaluated the association of CI-AKI on cardiovascular events in ACS patients with CKD. METHODS A total of 1059 ACS patients who underwent emergent PCI in our multicenter registry were enrolled (69±12 years, 804 men, 604 STEMI patients). CKD was defined as at least stage 3 CKD, and CI-AKI was defined as an increase of at least 0.5 mg/dL and/or an increase of at least 25% of pre-PCI to post-PCI serum creatinine levels within 1 week after the procedure. Primary endpoints included cardiovascular death, myocardial infarction, and cerebrovascular disorder (stroke or transient ischemic attack). RESULTS In our study, 368 (34.7%) patients had CKD. During follow-up periods (435±330 days), CI-AKI and primary endpoints occurred in 164 (15.5%) patients and 106 (10.0%) patients, respectively. Multivariate Cox proportional hazards model revealed that age, female gender, peak creatinine kinase>4000, IABP use, CI-AKI (hazard ratio [HR], 2.17; 95% confidential interval [CI], 1.52 to 4.00; P<0.001), and CKD (HR, 1.66; 95% CI, 1.01 to 2.72; P=0.046) were independent predictors of primary endpoints. Kaplan-Meier analysis showed that occurrence of primary endpoints increased significantly with an increase in CKD stage, and CI-AKI yielded worse long-term prognosis at every stage of CKD (P<0.001). CONCLUSIONS CI-AKI was revealed to be a significant incremental predictor of cardiovascular events at each stage of CKD in ACS patients.

Computer-Aided Detection and Evaluation of Lipid-Rich Plaque on Noncontrast Cardiac CT

OBJECTIVE Noncontrast electron beam CT (EBCT) and MDCT are established for the assessment of calcified plaque, but not lipid-rich plaque. We developed software to identify lipid-rich plaque with noncontrast electron beam tomography (EBT) and MDCT. MATERIALS AND METHODS A computer algorithm was developed to automatically find contiguous lipid-rich lesions with voxel intensities below a calculated patient-specific lipid threshold. Lipid density and lipid inhomogeneity in Hounsfield units were calculated in the proximal left coronaries of three populations: 34 low-risk patients (low-risk group < 6% Framingham risk score, no calcium), 31 high-risk patients (high-risk group > 20% Framingham risk score, no calcium), and 37 patients with calcified plaque (calcium group). RESULTS The mean lipid density was -19.6 +/- 3.0 (SD) H in the low-risk group, -25.3 +/- 8.2 H in the high-risk group, and -34.3 +/- 13.0 H in the calcium group (p < 0.05). The mean lipid inhomogeneity was 17.7 +/- 3.6 H in the low-risk group, 21.5 +/- 5.5 H in the high-risk group, and 29.0 +/- 7.6 H in the calcium group (p < 0.05). The mean interscan variability in lipid density and lipid inhomogeneity were 2.0 +/- 3.3 H and 2.1 +/- 3.6 H, respectively. In five patients, the locations of lipid-rich plaque correlated well with available intravascular sonography findings. CONCLUSION Our method may be able to identify lipid-rich plaque on noncontrast cardiac CT.

Patient motion correction for multiplanar, multi‐breath‐hold cardiac cine MR imaging

To correct for spatial misregistration of multi‐breath‐hold short‐axis (SA), two‐chamber (2CH), and four‐chamber (4CH) cine cardiac MR (CMR) images caused by respiratory and patient motion.

Preventive effect of statin pretreatment on contrast-induced acute kidney injury in patients undergoing coronary angioplasty: Propensity score analysis from a multicenter registry

BACKGROUND The prophylactic benefit of statins in reducing the incidence of contrast-induced acute kidney injury (CI-AKI) has been investigated in several studies with conflicting results. We sought to investigate whether statin pretreatment prevents CI-AKI in coronary artery disease (CAD) patients undergoing percutaneous coronary intervention (PCI). METHODS A total of 2198 CAD patients who underwent PCI, except for those undergoing dialysis or who died within 7 days after angioplasty, were analyzed from the ICAS (Ibaraki Cardiovascular Assessment Study) multicenter registry. Analyzed subjects were divided into 2 groups according to statin pretreatment: statin pretreatment (n=839) and non-statin pretreatment (n=1359). Selection bias of statin pretreatment was adjusted by propensity score-matching method: pretreatment statin (n=565) and non-statin pretreatment (n=565). CI-AKI was defined as an increase in serum creatinine of ≥ 25% or 0.5mg/dl from baseline within 1 week of contrast medium exposure. RESULTS A total of 192 (8.7%) patients developed CI-AKI. No significant differences were observed in baseline patient characteristics between the statin and non-statin pretreatment groups after propensity score matching. In the propensity score-matched groups, the incidence of CI-AKI was significantly lower in patients with statin pretreatment than in those without statin pretreatment (3.5% vs.10.6%, odds ratio [OR]: 0.31, 95% confidence interval [CI]: 0.18-0.52, P<0.001). Multivariate logistic regression analysis showed that statin pretreatment remained an independent negative predictor of CI-AKI (OR: 0.31, 95% CI: 0.18-0.53, P<0.001) among propensity score-matched subjects. CONCLUSIONS Statin pretreatment was associated with a significant decrease in the risk of CI-AKI in CAD patients undergoing PCI in the ICAS Registry.

Effect of individual proton pump inhibitors on cardiovascular events in patients treated with clopidogrel following coronary stenting: results from the Ibaraki Cardiac Assessment Study Registry.

Objectives: The aim of this study was to evaluate whether combination therapy of clopidogrel and proton pump inhibitors (PPIs) causes higher numbers of cardiovascular events than clopidogrel alone in Japanese patients. Background: PPIs are often prescribed in combination with clopidogrel following coronary stenting. PPIs are reported to diminish the effect of clopidogrel because both are metabolized by CYP2C19. However, no reports address the effects of PPIs on cardiovascular events following coronary stenting in the Japanese population. Methods: A total of 1,887 patients treated with clopidogrel following coronary stenting were enrolled in the Ibaraki Cardiac Assessment Study (ICAS) registry. All subjects were classified into two groups according to treatment without (n = 819) or with (n = 1,068) PPI. Propensity score analysis matched 1:1 according to treatment without PPI (n = 500) or with PPI (n = 500). Primary endpoint was the composite of all‐cause death or myocardial infarction. Results: No significant difference was observed in the primary endpoint between the group without PPI and the group with PPI (4.6% vs. 4.6%, P = 0.77). In contrast, a significant difference was found between the group without PPI and with PPI in regard to the incidence of gastrointestinal bleeding at the end of the follow‐up period and the specific PPI prescribed (2.4% vs. 0.8%, adjusted HR = 0.30, 95% Confidence interval 0.08‐0.87, P = 0.026) after propensity score matching. Conclusions: No significant association between PPI use and primary endpoint was observed in the Japanese population, whereas PPI use resulted in a significant reduction in the rate of gastrointestinal bleeding.

Acute hemodynamic effects of landiolol, an ultra-short-acting beta-blocker, in patients with acute coronary syndrome: Preliminary study

OBJECTIVES We aimed to evaluate acute hemodynamic effects and safety of landiolol in patients with acute coronary syndrome (ACS) treated with percutaneous coronary intervention (PCI). BACKGROUND Beta-blockers have been proven to be effective for the treatment of ischemic heart disease in both the acute and chronic phases. Landiolol, an ultra-short-acting and highly cardioselective beta-1 blocker, has become available in Japan. In the clinical setting, the hemodynamic response to landiolol administration remains unclear in patients presenting with ACS. METHODS From August 2007 to April 2008, landiolol was administered intravenously immediately before reperfusion procedure in 22 consecutive ACS patients (mean age, 63±9 years; 15 men) with a heart rate (HR) of ≥70 beats/min. The initial intravenous administration dose of landiolol was 20 μg/kg/min in all patients. The maintenance dose was titrated with the aim of reducing HR by 15%. Acute hemodynamic data including HR and systolic and diastolic blood pressure were serially evaluated. RESULTS HR dropped significantly (from 87±11 to 72±8beats/min, p<0.001) 20 min after landiolol initiation. However, systolic and diastolic pressure remained unchanged during administration of landiolol. Although landiolol was discontinued in 2 patients because of sinus bradycardia, no serious complications such as advanced degree atrioventricular block, requiring temporary cardiac pacing, severe hypotension, cardiogenic shock, or deterioration of heart failure were observed in the patients receiving landiolol. CONCLUSIONS Landiolol was safe and effective in reducing oxygen demand of the ischemic heart by reducing only HR without lowering blood pressure in patients with ACS undergoing PCI.

Prognostic study of cardiac and renal events in Japanese patients with chronic kidney disease and cardiovascular risk using myocardial perfusion SPECT : J-ACCESS 3 study design

Cardiovascular disease is the leading cause of morbidity and mortality in patients with chronic kidney disease. Recent studies have indicated that the incidence of cardiovascular disease increases inversely with estimated glomerular filtration rate. Although coronary angiography is considered the gold standard for detecting coronary artery disease, contrast‐induced nephropathy or cholesterol microembolization remain serious problems; therefore, a method of detecting coronary artery disease without renal deterioration is desirable. From this viewpoint, stress myocardial perfusion single photon emission computed tomography (SPECT) might be useful for patients with chronic kidney disease. We recently performed the Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated SPECT (J‐ACCESS) investigating patients with suspected or extant coronary artery disease and the J‐ACCESS 2 study of patients with diabetes. The findings from these studies showed that SPECT can detect coronary artery disease and help to predict future cardiac events. Thus, we proposed a multicenter, prospective cohort study called “J‐ACCESS 3” in patients with chronic kidney disease and cardiovascular risk. The study aimed at predicting cardiovascular and renal events based on myocardial perfusion imaging and clinical backgrounds. We began enrolling patients in J‐ACCESS 3 at 74 facilities from April 2009 and will continue to do so until 31 March 2010, with the aim of having a cohort of 800 patients. These will be followed up for three years. The primary endpoints will be cardiac death and sudden death. The secondary endpoints will comprise any cardiovascular or renal events. This study will be completed in 2013. Here, we describe the design of the J‐ACCESS 3 study.

Rapid Assessment of Left Ventricular Segmental Wall Motion, Ejection Fraction, and Volumes with Single Breath-Hold, Multi-Slice TrueFISP MR Imaging

BACKGROUND AND OBJECTIVE To reduce imaging time and complexity, we sought to determine whether single breath-hold, multi-slice TrueFISP (SB-MST) magnetic resonance imaging (MRI) method is comparable to standard multi-breath-hold, multi-slice TrueFISP (MB-MST) for assessment of left ventricular (LV) wall motion abnormality (WMA), volumes, and ejection fraction (EF). METHODS AND RESULTS We studied 62 patients having cardiac MRI at 1.5-Tesla. After acquiring standard MB-MST (one slice per breath-hold), SB-MST was performed, acquiring 3 short- and 2 long-axis views over only 20 heartbeats. Using both techniques, wall motion was scored using a 6-point, 17-segment LV model for all scans (62 patients x 2 techniques/patient = 124 scans) on two separate occasions. Separately, EF and ventricular volumes were evaluated using both MB-MST and SB-MST. For all analyses, MB-MST was considered the standard against which SB-MST was compared. Twenty-six of 62 patients exhibited at least one segmental WMA by MB-MST. Exact agreement for wall motion was found in 965/1054 segments (92%, kappa = 0.74, p < 0.001), and agreement was within 1 score point in 1010/1054 segments (96%). Considering a score >1 abnormal, exact agreement for presence of WMA was found in 131/193 segments (68%) abnormal by MB-MST and for absence of WMA in 838/861 segments (97%) normal by MB-MST. Agreement within 1 score point occurred in 167/193 abnormal (87%) and in 843/861 normal segments (98%). There were no significant differences in agreement between first and second read of the data. Variability of SB-MST on read one versus read two was small (5%, 996/1054 segments read identically, p = ns) and statistically identical to variability of MB-MST on read one versus read two (4%, 1007/1054 segments read identically, p = ns). For end-diastolic volumes, end-systolic volumes, and EF using SB-MST compared to MB-MST, mean differences were 9 +/- 15 ml, 6 +/- 12 ml, and 2 +/- 5%, and correlations were r = 0.97, 0.98 and 0.95, respectively. CONCLUSION SB-MST accurately assesses wall motion, volumes and EF. This approach may serve as a screening exam for assessment of WMA and, under select circumstances, may substitute for standard multi-breath-hold method in situations requiring rapid accurate assessments of LV function.

Enhancement patterns detected by multidetector computed tomography are associated with microvascular obstruction and left ventricular remodelling in patients with acute myocardial infarction

AIMS This study evaluated the clinical value of myocardial contrast-delayed enhancement (DE) with multidetector computed tomography (MDCT) for detecting microvascular obstruction (MVO) and left ventricular (LV) remodelling revealed by DE magnetic resonance imaging after acute myocardial infarction (AMI). METHODS AND RESULTS In 92 patients with first AMI, MDCT without iodine reinjection was performed immediately following successful percutaneous coronary intervention (PCI). Delayed-enhancement magnetic resonance imaging performed in the acute and chronic phases was used to detect MVO and LV remodelling (any increase in LV end-systolic volume at 6 months after infarction compared with baseline). Patients were divided into two groups according to the presence (n = 33) or absence (n = 59) of heterogeneous enhancement (HE). Heterogeneous enhancement was defined as concomitant presence of hyper- and hypoenhancement within the infarcted myocardium on MDCT. Microvascular obstruction and LV remodelling were detected in 49 (53%) and 29 (32%) patients, respectively. In a multivariable analysis, HE and a relative CT density >2.20 were significant independent predictors for MVO [odds ratio (OR) 13.5; 95% confidence interval (CI), 2.15-84.9; P = 0.005 and OR 12.0; 95% CI, 2.94-49.2; P < 0.001, respectively). The presence of HE and relative CT density >2.20 showed a high positive predictive value of 93%, and the absence of these two findings yielded a high negative predictive value of 90% for the predictive value of MVO. Heterogeneous enhancement was significantly associated with LV remodelling (OR 6.75; 95% CI, 1.56-29.29; P = 0.011). CONCLUSION Heterogeneous enhancement detected by MDCT immediately after primary PCI may provide promising information for predicting MVO and LV remodelling in patients with AMI.