Usefulness of Stress Myocardial Perfusion Imaging for Evaluating Asymptomatic Patients After Coronary Stent Implantation

Usefulness of serial post-systolic shortening by speckle tracking echocardiography to predict major adverse cardiovascular events and segmental function improvement after acute myocardial infarction

Purpose

The aim is to determine whether serial post-systolic shortening (PSS) using speckle tracking echocardiography (STE) could predict major adverse cardiovascular events (MACE), especially symptom-driven infarct-related artery (IRA) revascularization and improvement in segmental function in post-myocardial infarction patients.

Methods/Results

Ninety-four patients (average age 61.1 ± 12.5 y, 84 [84.9%] male) with new-onset acute myocardial infarction were enrolled. Serial echocardiography was performed during the initial presentation, and at 3, 6 and 12 months after admission. PSS, strain and systolic strain rate were calculated using STE. Improvement in segmental function was defined as a decrease of ≧1 grade in wall motion score. During the follow-up (29.4 ± 12.7months), 22 patients (23.4%) had MACE and 17 patients had symptom-driven IRA revascularization. In multivariate model, PSS at 3 months was independently predictive for symptom-driven IRA revascularization (Hazard ratio (HR) = 0.5, 95% CI = 0.26–0.97) and for MACE (HR = 0.4, 95% CI = 0.24–0.67) (p < 0.05). Segmental function improvements were found in 255 segments (66.1%) and ROC curve analyses showed that AUC (95% CI) of the initial PSS was 0.7(0.65–0.77) (cut-off values = -1.08, sensitivity = 58%, specificity = 73% specificity).

Conclusions

Post-systolic shortening at 3 months is an independent predictor for symptom-driven IRA revascularization and MACE. Regional wall motion recovery also could be predicted by initial PSS. Serial assessment of two-dimensional STE should be investigated in post-myocardial infarction patients in the future.

Chest Pain with Normal Thallium-201 Myocardial Perfusion Image - Is It Really Normal?

BACKGROUND

Thallium-201 myocardial perfusion image (MPI) is commonly used to detect coronary artery disease in patients with chest pain. Although a normal thallium-201 MPI result is generally considered to be a good prognosis and further coronary angiogram is not recommended, there are still a few patients who suffer from unexpected acute coronary events. The aim of this study was to investigate the clinical prognosis in patients with normal thallium-201 MPI.

METHODS

From January 2006 to August 2012, a total 22,003 patients undergoing thallium-201 MPI in one tertiary center were screened. Of these, 8092 patients had normal results and were investigated retrospectively. During follow-up, 54 patients underwent coronary angiogram because of refractory typical angina pectoris or unexpected acute coronary events. These 54 patients were divided into 2 groups: group I consisted of 26 (48.1%) patients with angiography-proven significant coronary artery stenosis, and group II consisted of 28 (51.9%) patients without significant stenosis.

RESULTS

Patients in group I had a higher prevalence of prior coronary stenting and electrocardiographic features of ST depression compared with patients in group II. The multivariate analysis demonstrated that both prior coronary stenting and ST depression were risk predictors of unexpected acute coronary events in the patients with normal thallium-201 MPI [odds ratio (OR), 5.93; 95% confidence interval (CI): 1.03-34.06, p = 0.05 and OR, 7.10; 95% CI: 1.28-39.51, p = 0.03,respectively].

CONCLUSIONS

Although there is a low incidence of unexpected acute coronary events in patients with chest pain and normal thallium-201 MPI, physicians should be aware of the potentials risk in certain patients in this specific population.

The utility of the combination of the corrosion cast method and post mortem MSCT scans

A careful post-mortem investigation is needed to determine the cause of death of patients bearing coronary stents and to describe complications of stent implantation. The main purpose of this study was to combine post mortem methods of CT angiography and corrosion cast preparation for the visualization of coronary stenoses, coronary stents, instent restenosis, and stent occlusion. Injection-corrosion method was combined with post-mortem MSCT angiography to characterize the pathomorphological changes after stent implantation in 6 male cadaver hearts. Multi-slice computed tomography was employed to visualize the coronary artery system. For image post processing, multiplanar reconstructions, maximal intensity projections and three dimensional reconstructions were used. This study was assessing the feasibility of post mortem MSCT for intracoronary stent evaluation. We described a method for characterization of the coronary side branch stenosis caused by stent implantation. Post mortem CT imaging proved to be a feasible and highly reproducible technique for the characterization of pathological changes in the coronary system.

Diagnostic value of myocardial SPECT to detect in-stent restenosis after drug-eluting stent implantation

Different angiographic patterns and restenosis rate may affect diagnostic value of single-photon emission computed tomography (SPECT) in the era of drug-eluting stents (DES). We aimed to determine the ability of myocardial SPECT to detect in-stent restenosis (ISR) in patients treated with DES compared to that of patients treated with bare metal stent (BMS). We evaluated 228 consecutive patients who underwent 6 months follow-up SPECT and coronary angiography (CAG) after stent implantation. In 228 patients, 354 vessels were treated with stent implantation (BMS, n = 105; DES, n = 249) and 65 (18.4%) vessels showed ISR (angiographic % diameter stenosis ≥ 50%) at the 6-month follow-up CAG. In patients with BMS-ISR (n = 37), restenosis was primarily diffuse (70.3%), whereas patients with DES-ISR (n = 28) exhibited more focal restenosis (53.6%, p = 0.028). The sensitivity and specificity of myocardial SPECT did not differ significantly between patients with BMS and those with DES (BMS vs. DES: sensitivity 56.8 vs. 39.3%, p = 0.163; specificity 72.1 vs. 76.5%, p = 0.460). Evaluation of 71 false positive and 33 false negative lesions showed that the most common cause of false-positive results in SPECT was the perfusion decrease which improved but not disappeared compared with the baseline (46 among 71 vascular territories). Despite different patterns of restenosis and ISR rates, the diagnostic value of SPECT did not differ between BMS and DES. Further study looking at ISR in larger number of patients and using other protocol such as Fleming-Harrington Redistribution Wash-in Washout may give additional information.

The usefulness of delayed enhancement magnetic resonance imaging for diagnosis and evaluation of cardiac function in patients with cardiac sarcoidosis

OBJECTIVES

Cardiac involvement is an important prognostic factor in patients with sarcoidosis. We evaluated the usefulness of delayed enhancement MRI (DE-MRI) for diagnosing cardiac sarcoidosis by comparing with nuclear imaging and studying the correlation between DE area and left ventricular (LV) function.

METHODS

Twelve patients (male:female 3:9) diagnosed as having sarcoidosis underwent Gd-MRI, myocardial perfusion SPECT (Tl-201, Tc-99m sestamibi), Ga-67 scintigraphy, and/or F-18 FDG-PET.

RESULTS

DE was observed in 5 patients, and was positive in 39 (39%) of 100 LV segments. The corresponding perfusion defects in myocardial perfusion SPECT were undetectable in 14 (36%) segments. DE distributed mainly in mid- to epi-myocardium, and the lack of perfusion defects in myocardial perfusion SPECT was more prominent in less transmural DE segments. Two patients with diffuse DE and 1 case with focal DE exhibited positive cardiac uptake in Ga-67 scintigraphy, and 2 other cases with focal DE showed cardiac uptake in F-18 FDG-PET. In 7 patients without DE, there were no significant findings in nuclear imaging. Both LV end-diastolic and end-systolic volume were positively and LV ejection fraction was negatively correlated with the extent of DE area. Four patients treated with corticosteroid showed improvement in nuclear imaging and slight decreases in DE area but no recovery in LV function.

CONCLUSIONS

DE-MRI is useful to diagnose the cardiac involvement of sarcoidosis and to evaluate cardiac function. It is likely that the distribution of DE in mid- to epi-myocardium is the characteristic of cardiac sarcoidosis, and the larger DE area may be correlated with poor LV function.

New diagnostic technique in multi-slice computed tomography for in-stent restenosis: pixel count method

OBJECTIVES

A diagnostic technique to objectively determine coronary in-stent stenosis was developed with multi(16)-slice computed tomography (MSCT), and it was compared with coronary angiography (CAG) in clinical cases.

BACKGROUND

MSCT is expected to replace coronary angiography as a new non-invasive examination. Evaluation of highly calcified or in-stent lesions with CT is generally thought to be difficult.

METHODS

Twenty lesions among 16 consecutive patients that were implanted with coronary stents were examined with both MSCT and CAG at follow-up. The minor axis cross sections of the stents were reconstructed at intervals of 1.5 mm with multiplanar reformation (MPR). The pixel with a higher CT value than the lowest CT value in the standard cross section at the proximal site out of stent was counted to determine the presence/absence of a stenotic lesion.

RESULTS

Among 20 lesions, one case was not able to be evaluated with MSCT. MSCT correctly detected 3 of 4 cases with in-stent stenosis (sensitivity 75%), and 14 of 16 cases with no in-stent stenosis (specificity 88%, negative predictive value 93%, positive predictive value 75%). If analysis was made per-artery, sensitivity and specificity were 100% (3 of 3) and 87% (13 of 15), respectively, for detection of in-stent stenosis.

CONCLUSIONS

This study was performed to examine a unique diagnostic technique: pixel count method, for coronary in-stent stenosis with MSCT. It showed that the coronary in-stent stenosis could be determined when stent struts were clearly imaged. Further examination is required with various stents, especially those with a diameter of 3.0 mm or smaller.