Clinical correlation between increased lung to heart ratio of tecnetium-99m sestamibi and multivessel coronary artery disease

The role of myocardial perfusion imaging in predicting myocardial ischemia in patients diagnosed with long COVID

OBJECTIVE

Incomplete recovery with long-term complications weeks beyond the acute coronavirus disease 2019 (COVID-19) infection is referred to as long COVID. Among the well-known long-term complications of COVID-19, myocardial damage is a frequently encountered side effect. Yet there is a lack of data for identifying high-risk patients who are more likely to develop long-term cardiovascular complications following COVID-19. Myocardial perfusion imaging (MPI) is the primary functional imaging modality in evaluating myocardial ischemia This study aimed to investigate the role of MPI in predicting myocardial ischemia in patients diagnosed with long COVID.

METHODS

Subjects were selected from eligible long COVID patients and control subjects without a prior history of COVID-19 who were referred to the nuclear medicine department for stress and rest single-photon emission computed tomography (SPECT) MPI. All participants' past medical records and clinical, and demographic characteristics were scanned. In addition, patients undergoing coronary angiography (CAG) following SPECT MPI were documented and patients with critical coronary stenosis were identified.

RESULTS

Our results revealed that long COVID patients had higher rates of abnormal summed stress scores compared to the control subjects (p < 0.05). Additionally, serum CRP level, SPECT lung-to-heart ratio (LHR), and the presence of long COVID were independent predictors of ischemia. The presence of long COVID was the best predictor of ischemia among the aforementioned parameters (p < 0.001).

CONCLUSION

Our data indicate that SPECT MPI provides comprehensive information on myocardial perfusion and left ventricular function in long COVID patients.

Lung Sestamibi Uptake on Myocardial Perfusion Imaging and Outcomes in Chronic Kidney Disease

BACKGROUND AND OBJECTIVES

In patients with CKD and end-stage kidney disease (ESKD), cardiac stress testing has low sensitivity and specificity for coronary disease. Alternate markers that are derived during the stress testing may enhance the predictive characteristic of stress testing. The objective was to examine the predictive characteristic of lung-to-heart ratio (LHR) in patients with CKD and ESKD.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

Retrospective parallel cohort of ESKD and CKD not on dialysis (CKD-ND) who underwent stress testing with nuclear myocardial perfusion imaging utilizing sestamibi tracer and regadenoson. Stress LHR was calculated by the processing software and reported. Patients were analyzed by tertile of LHR (≤0.28, 0.29-0.32, ≥0.33). The primary outcome was a composite of all-cause mortality, hospitalization for myocardial infarction or unstable angina, or revascularization.

RESULTS

There were 144 CKD-ND and 145 ESKD patients. Patients with ESKD had greater comorbidity burden than CKD-ND. Stress tests were more often performed for pre-operative risk assessment among ESKD versus CKD-ND (53.8 vs. 5.6%, p < 0.001). ESKD patients more likely had ischemia identified on stress testing (19.3 vs. 8.3%, p = 0.001). Mean LHR was 0.31 (Standard deviation - SD: 0.09) and was similar across CKD-ND stages and ESKD. Primary outcome in the lowest (23%) and highest (33.3%) LHR tertile was higher than the middle tertile (12.8%); p = 0.005. This finding was similar between CKD-ND and ESKD and persisted in multivariable analysis.

CONCLUSIONS

LHR ≤0.28 and ≥0.33 are independently associated with higher risk for death in patients with CKD-ND and ESKD. Future studies are warranted to understand the association of extreme LHR values and outcomes in this high-risk population.

Adenosine stress myocardial perfusion imaging in octogenarians: Safety, tolerability, and long-term prognostic implications of hemodynamic response and SPECT-related variables

BACKGROUND

Evaluation of tolerability, safety, and prognostic implications of adenosine stress myocardial perfusion imaging (MPI) in octogenarians.

METHODS

370 octogenarians (49% known coronary artery disease) were studied. Hemodynamic response, MPI-related data, and rest-left ventricular ejection fraction (LVEF) based on echocardiography were registered per patient, and prospective follow-up was performed to document all-cause death (ACD), cardiac death (CD), myocardial infarction (MI), and late revascularization.

RESULTS

No deaths or MIs were observed during adenosine infusion or the short-term post-infusion period. 86% of patients were able to tolerate a 6-minute infusion. All side effects terminated spontaneously after infusion cessation, except for one case of pulmonary oedema. After 9.3 years, there were 124 ACDs, 62 CDs, 16 MIs, and 35 revascularizations. Differences between survival curves of summed stress score (SSS)-based risk groups were significant for all end points (P < .001). SSS and LVEF were independent predictors of all end points (P ≤ .01) and lung uptake of cardiac end points. ΔHR <10 bpm (OR = 1.78, P = .004) and inability to increase HR by >10 bpm and decrease systolic blood pressure by >10 mmHg (OR = 2, P = .02) during adenosine infusion were independent predictors of ACD and CD, respectively. Hemodynamic response variables, SSS, and lung uptake provided incremental prognostic value over pre-test data for ACD and CD.

CONCLUSIONS

In octogenarians, adenosine stress MPI is well tolerated and provides effective long-term risk stratification.

Left main coronary artery disease: A review of the spectrum of noninvasive diagnostic modalities

Medically managed significant left main (LM) stem disease has been considered a determinant of increased cardiac mortality approaching 50% at 3-year follow-up. Despite the clinical significance of LM disease, studies comparing the various diagnostic modalities, especially noninvasive, are sparse. Clinicians, particularly imagers, should be aware of the strengths and weaknesses of existing modalities to diagnose LM disease as integrating many clues (history, symptoms, electrocardiogram, and stress hemodynamics are essential to suspect this diagnosis and proceed to the next step). Here we review the existing data on the current role of electrocardiography, nuclear myocardial perfusion imaging (single photon emission computed tomography and positron emission tomography), stress echocardiography, cardiac computed tomography, and cardiac magnetic resonance imaging in diagnostic evaluation of LM disease. Wherever applicable we have extended our discussion to multivessel coronary artery disease encompassing scenarios where LMS can present as LM equivalent with or without extensive multivessel coronary artery disease.

The prognostic value of non-perfusion variables obtained during vasodilator stress myocardial perfusion imaging

Myocardial perfusion imaging (MPI) is an established diagnostic test that provides useful prognostic data in patients with known or suspected coronary artery disease. In more than half of the patients referred for stress testing, vasodilator stress is used in lieu of exercise. Unlike exercise, vasodilator stress does not provide information on exercise and functional capacity, heart rate recovery, and chronotropy, and ECG changes are less frequent. These non-perfusion data provide important prognostic and patient management information. Further, event rates in patients undergoing vasodilator MPI are higher than in those undergoing exercise MPI and even in those with normal images probably due to higher pretest risk. However, there are a number of non-perfusion variables that are obtained during vasodilator stress testing, which have prognostic relevance but their use has not been well emphasized. The purpose of this review is to summarize the prognostic values of these non-perfusion data obtained during vasodilator MPI.

Gated myocardial perfusion scintigraphy in children with sickle cell anemia: correlation with echocardiography

OBJECTIVES

The heart is one of the organs affected by sickle cell anemia (SCA). This prospective study has aimed to evaluate myocardial perfusion and left ventricle (LV) function in children with SCA by gated myocardial perfusion scintigraphy (G-MPS) and to compare the results with echocardiographic parameters.

METHODS

Forty-three patients with SCA were evaluated by G-MPS and echocardiography. Myocardial perfusion and motion with thickening function were analyzed both visually and quantitatively. End-diastolic (EDV), end-systolic volumes (ESV), ejection fraction (EF), lung-to-heart (L/H) ratio were also calculated.

RESULTS

None of the patients showed stress perfusion impairment in G-MPS. LV dilatation in 15 patients was observed both by G-MPS and echocardiography. EF values were within normal limits. Correlation between EF values calculated by two methods was not statistically significant. However, LV dilatation detected by both methods and EDV-ESV values in G-MPS were correlated to end-diastolic and end-systolic diameters calculated in echocardiography (p<0.05). M-Mode echocardiography revealed higher myocardial performance index (LV-MPI) in patients with LV dilatation. There was also a significant relationship between LV dilatation and frequent blood transfusions (>5/years) and acute chest syndrome (p<0.05).

CONCLUSION

Myocardial perfusion impairment in children with SCA is not frequently observed. Thus, performing the scintigraphy only in patients with cardiac symptoms should be considered. Since EF values of the children with SCA are not deteriorated in early stages, LV-MPI and LV dilatation should be considered as a significant parameter other than EF or perfusion data.

Gated myocardial perfusion scintigraphy in children with myocarditis: can it be considered as an indicator of clinical outcome?

PURPOSE

Myocarditis is an inflammation of the heart muscle and represents a challenge for diagnosis and treatment. On account of the lack of sensitivity and specificity of routine cardiac tests, there is a need for accurate diagnostic imaging. The aim of this study is to review the role of gated 99Tc-methoxyisobutylisonitrile myocardial perfusion scintigraphy (G-MPS) in the diagnosis and follow-up of the patients with myocarditis in comparison with gallium scintigraphy.

MATERIALS AND METHODS

Thirteen patients with a clinical diagnosis of myocarditis were included in the study. All underwent rest G-MPS and the images were then evaluated by quantitative perfusion single-photon emission computed tomography and quantitative gated single photon emission computed tomography software program. Visual evaluation of perfusion was performed as well as analysis of motion with thickening function [expressed as summed rest score, summed motion score, and summed thickening score (STS)] with calculation of ejection fraction (EF) and lung-to-heart (L/H) ratio. Eight patients underwent 67Ga scintigraphy. Clinical, echocardiography, and cardiac enzymes (creatinine kinase-MB, myoglobulin, troponin T, brain natriuretic peptide) data were gathered from the patients' charts. Clinical outcome was grouped according to prognosis. Spearman's correlation (SC) test was used for comparison analysis.

RESULTS

Myocardial perfusion defects were observed in eight patients. Perfusion defects in the left ventricle involve a mean of 7.25% (range: 1-11%), whereas wall motion abnormality on G-MPS was more prominent, which showed to be a better marker for myocardial inflammation and necrosis. The 67Ga scintigraphy findings were normal in all, but two. The G-MPS EF (33+/-21%) was slightly lower than the echocardiography EF (40+/-15%), but with close correlation (SC coefficient: 0.635). Comparison of scintigraphic findings with clinical parameters showed that summed motion score with G-MPS EF and STS with L/H ratios were highly correlated (0.932 and 0.622, respectively). The maximum brain natriuretic peptide and L/H ratio with STS were highly correlated with the patients' outcomes (SC coefficient: -0.621, 0.821, and 0.579, respectively), as well.

CONCLUSION

Tc-methoxyisobutylisonitrile G-MPS is therefore helpful in providing additional diagnostic and prognostic information in patients with myocarditis.

Stress-induced abnormalities in myocardial perfusion imaging that are not related to perfusion but are of diagnostic and prognostic importance

INTRODUCTION

Certain stress-induced ancillary findings on myocardial perfusion scintigraphy increase the likelihood that the patient has coronary artery disease (CAD); furthermore, among CAD patients, they indicate more severe and extensive disease, placing these patients at higher risk for future cardiac events. Indeed, in studies with no obvious perfusion defect yet with serious CAD--for example, balanced ischemia--it can be these high-risk findings that necessitate invasive intervention.

DISCUSSION

Besides reversible perfusion defects, such findings include increased pulmonary radiotracer uptake, transient cavity dilatation, increased end-diastolic or end-systolic volume, decreased post-stress ejection fraction, and increased right ventricular tracer uptake on stress images. The pathophysiology underlying these findings is clearly different as they do not always occur together, and each independently predicts more severe and extensive CAD. In the current review, these findings are defined and their significance in diagnosing patients with suspected or known CAD is discussed.