Prognostic value of regadenoson myocardial single-photon emission computed tomography in patients with different degrees of renal dysfunction

Comparison of left ventricle mechanical dyssynchrony parameters in ischemic and non-ischemic patients using 13N-NH3 PET/CT

BACKGROUND-AIM

The relationship between perfusion pattern and stress-induced changes in Left Ventricular Mechanical Dyssynchrony (LVMD) has been previously described with controversial results using stress-rest perfusion imaging studies. The aim of this study was to assess the relationship between perfusion pattern and stress-induced changes in LVMD usingo regadenoson/rest13N-NH3 PET/CT.

METHODS

There were 74 patients who underwent stress-rest 13N-NH PET/CT from January 2014 to October 2018 excluding patients with left bundle branch block, ventricular pacing and myocardial necrosis. The patients were divided into those with reversible perfusion defects at stress (Ischemic group, n = 18) and patients without reversible perfusion defects (non-ischemic group, n = 56). The LVMD parameters included: phase standard deviation (PSD) and phase histogram bandwidth (PHB), after stress and at rest. The ΔPSD (post-stressPSD-restPSD) and ΔPHB (post-stressPHB-restPHB) were calculated to measure stress-induced changes in LVMD.

RESULTS

There were no significant differences in LVMD parameters between post-stress and at rest in both groups. The PSD post-stress, ΔPSD and PHB post-stress were significantly higher in the ischemic group.

CONCLUSIONS

Using a vasodilator as a stress, the PSD and PHB post-stress and ΔPSD were significantly higher in the ischemic patients than the non-ischemic group, while there were no significant differences in each cohort between stress and rest indices.

The prognostic utility of regadenoson SPECT myocardial perfusion imaging in patients with end-stage renal disease: The largest cohort to date

BACKGROUND

There are limited data on the prognostic utility of regadenoson SPECT myocardial perfusion imaging (MPI) in patients with end-stage renal disease (ESRD).

METHODS AND RESULTS

In a single-center, retrospective study, we analyzed consecutive ESRD patients who underwent regadenoson SPECT-MPI. The severity of MPI abnormalities and ischemic burden were determined quantitatively. The primary endpoint was major adverse cardiac events (MACE), defined as the composite of cardiac death or myocardial infarction. Among 1,227 subjects (mean age 54 ± 13 years, 47% men), 60 (5%) MACE were observed during a mean follow-up of 2.5 ± 1.8 years. The presence and severity of MPI abnormalities and ischemic burden were associated with a stepwise increase in MACE risk. Abnormal MPI (SSS ≥ 4) was associated with increased MACE risk, independent and incremental to relevant clinical covariates; adjusted hazard ratio, 1.95; 95% confidence interval, 1.15-3.32; Δχ2 = 5.97; P = .013. Myocardial ischemia (SDS ≥ 2) was associated with a trend towards increased MACE risk; adjusted hazard ratio, 1.63; 95% confidence interval, 0.96-2.77; Δχ2 = 3.12; P = .072.

CONCLUSION

In the largest cohort to date, we demonstrated the incremental prognostic value of abnormal MPI in predicting MACE risk in ESRD patients. Given its size, our study provides improved risk estimates in this population compared to previous reports.

Coronary Artery Disease in Chronic Kidney Disease: Need for a Heart-Kidney Team-Based Approach

Chronic kidney disease and coronary artery disease are co-prevalent conditions with unique epidemiological and pathophysiological features, that culminate in high rates of major adverse cardiovascular outcomes, including all-cause mortality. This review outlines a summary of the literature, and nuances pertaining to non-invasive risk assessment of this population, medical management options for coronary heart disease and coronary revascularisation. A collaborative heart-kidney team-based approach is imperative for critical management decisions for this patient population, especially coronary revascularisation; this review outlines specific periprocedural considerations pertaining to coronary revascularisation, and provides a proposed algorithm for approaching revascularisation choices in patients with end-stage kidney disease based on available literature.

The prognostic value of regadenoson SPECT myocardial perfusion imaging: The largest cohort to date

BACKGROUND

Data on the prognostic value of regadenoson SPECT myocardial perfusion imaging (MPI) is limited and based on small cohorts.

METHODS AND RESULTS

We conducted a single-center, retrospective cohort study of 10,275 consecutive patients who underwent regadenoson SPECT-MPI. Among the study subjects, 28.7% had abnormal MPI and 25.5% had myocardial ischemia. Patients were followed for a mean of 2.4 ± 2.2 years for major adverse cardiac events (MACE), defined as cardiac death or myocardial infarction. There was a significant stepwise increase in MACE with an increasing burden of perfusion abnormality (P < .001) and myocardial ischemia (P < .001). Abnormal MPI (adjusted HR 1.52; 95% CI 1.21 to 1.91) and myocardial ischemia (adjusted HR 1.53; 95% CI 1.25 to 1.89) were associated with MACE, independent of and incremental to clinical covariates and left ventricular ejection fraction (LVEF). Moreover, post-stress LVEF, LVEF reserve, and left ventricular end-diastolic volume added significant prognostic information. Transient ischemic dilation ≥ 1.31 did not provide incremental prognostic value (adjusted HR 1.02; P = .906).

CONCLUSION

In the largest cohort to date, we demonstrated that the presence and severity of perfusion abnormality and myocardial ischemia on regadenoson stress SPECT-MPI are associated with an independent increase in MACE.

Diagnostic Value of Structural and Functional Neuroimaging in Autoimmune Epilepsy

Epilepsy is a common nervous system disease, which affects about 70 million people all over the world. In 2017, the International League Against Epilepsy (ILAE) considered immune factors as its independent cause, and the concept of autoimmune epilepsy (AE) was widely accepted. Early diagnosis and timely treatment can effectively improve the prognosis of the disease. However, due to the diversity of clinical manifestations, the expensive cost of autoantibody detection, and the increased prevalence in Western China, the difficulty for clinicians in early diagnosis and treatment has increased. Fortunately, convenient and fast imaging examinations are expected to help even more. The imaging manifestations of AE patients were characteristic, especially the combined application of structural and functional neuroimaging, which improved the diagnostic value of imaging. In this paper, several common autoantibodies associated with AE and their structure and function changes in neuroimaging were reviewed to provide help for neurologists to achieve the goal of precision medicine.

SPECT/CT Imaging: A Noninvasive Approach for Evaluating Serial Changes in Angiosome Foot Perfusion in Critical Limb Ischemia

Objective: To investigate the feasibility of serial radiotracer-based imaging as a noninvasive approach for quantifying volumetric changes in microvascular perfusion within angiosomes of the foot following lower extremity revascularization in the setting of critical limb ischemia (CLI).

Approach: A CLI patient with a nonhealing foot ulcer underwent single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging of the feet before and after balloon angioplasty of the superficial femoral artery (SFA) and popliteal artery. SPECT/CT imaging was used to evaluate serial changes in angiosome perfusion, which was compared to quantitative changes in peripheral vascular anatomy and hemodynamics, as assessed by standard clinical tools that included digital subtraction angiography (DSA), ankle-brachial index (ABI), and toe-brachial index (TBI).

Results: Following revascularization, upstream quantitative improvements in stenosis of the SFA (pre: 35.4% to post: 11.9%) and popliteal artery (pre: 59.1% to post: 21.7%) shown by DSA were associated with downstream angiosome-dependent improvements in SPECT microvascular foot perfusion that ranged from 2% to 16%. ABI measurement was not possible due to extensive arterial calcification, while TBI values decreased from 0.26 to 0.16 following revascularization.

Innovation: This is the first study to demonstrate the feasibility of assessing noninvasive volumetric changes in angiosome foot perfusion in response to lower extremity revascularization in a patient with CLI by utilizing radiotracer-based imaging.

Conclusion: SPECT/CT imaging allows for quantification of serial perfusion changes within angiosomes containing nonhealing ulcers and provides physiological assessment that is complementary to conventional anatomical (DSA) and hemodynamic (ABI/TBI) measures in the evaluation of lower extremity revascularization.

Risk Stratification and Treatment of Coronary Disease in Chronic Kidney Disease and End-Stage Kidney Disease

Patients with advanced chronic kidney disease have an enormous burden of cardiovascular morbidity and mortality, but, paradoxically, their representation in randomized trials for the evaluation and management of coronary artery disease has been limited. Clinicians therefore are faced with the conundrum of synergizing evidence from observational studies, expert opinion, and extrapolation from the general population to provide care to this complex and clinically distinct patient population. In this review, we address clinical risk stratification of patients with chronic kidney disease and end-stage kidney disease using traditional cardiovascular risk factors, noninvasive functional and structural cardiac imaging, invasive coronary angiography, and cardiovascular biomarkers. We highlight the unique characteristics of this population, including the high competing risk of all-cause mortality relative to the risk of major adverse cardiac events, likely owing to important contributions from nonatherosclerotic mechanisms. We further discuss the management of coronary artery disease in patients with chronic kidney disease and end-stage kidney disease, including evidence pertaining to medical management, coronary revascularization with percutaneous coronary intervention, and coronary artery bypass grafting. Our discussion includes considerations of drug-eluting versus bare metal stents for percutaneous coronary intervention and off-pump versus on-pump coronary artery bypass graft surgery. Finally, we address currently ongoing randomized trials, from which clinicians are optimistic about receiving guidance regarding the best strategies to incorporate into their practice for the evaluation and management of coronary artery disease in this high-risk population.

Regadenoson use in chronic kidney disease and end-stage renal disease: A focused review

Regadenoson is a selective A2A adenosine receptor agonist that has been approved as a vasodilator stress agent with single-photon emission-computed tomography (SPECT) myocardial perfusion imaging (MPI). Since its approval by the Food and Drug Administration (FDA) in 2008, it has become the most commonly used pharmacologic stress agent with SPECT-MPI. Given that it is predominantly renally excreted, its use in patients with chronic kidney disease has been the subject of active post-marketing clinical research. Until recently, prescribing information regarding the use of regadenoson in patients with end-stage renal disease (ESRD) was not defined in the package insert. Based on accumulating data since its initial approval, the FDA has recently outlined the use of regadenoson in patients with ESRD in a label update on January 17, 2017. In this review, we discuss the evidence leading to the recent label update, focusing on the pharmacokinetics of regadenoson in patients with impaired kidney function, the safety and tolerability of regadenoson in patients with chronic kidney disease and ESRD, and the prognostic value of regadenoson stress MPI in this patient population.

Stress SPECT Myocardial Perfusion Imaging in End-Stage Renal Disease

PURPOSE OF REVIEW

Patients with end-stage renal disease (ESRD) have an increased risk of cardiovascular morbidity and mortality. Cardiac risk assessment, though challenging, is critical in these high-risk patients, particularly in the pre-transplant population. In this review, we discuss the burden of coronary artery disease in the ESRD population and review the literature on the diagnostic and prognostic performance, clinical value, and future directions of single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in ESRD patients.

RECENT FINDINGS

Stress myocardial perfusion imaging provides incremental prognostic value to clinical data. The AHA/ACCF consensus statement on the cardiac assessment of kidney transplant candidates provides some guidance on the selection of asymptomatic patients for further non-invasive risk stratification. Additionally, the novel selective A_2A receptor agonist vasodilator stress agent, regadenoson, is safe and effective in ESRD and has recently been approved by the Food and Drug Administration for use in this population. Ancillary stress MPI findings, namely heart rate response to vasodilator stress, can provide incremental risk stratification.

SUMMARY

While myocardial perfusion imaging is widely used as a risk assessment tool, its utilization and clinical implications in the ESRD population are controversial. Though stress SPECT-MPI has imperfect diagnostic accuracy in this specific patient population, it is still a valuable non-invasive modality in cardiovascular risk assessment.

The prognostic value of regadenoson SPECT myocardial perfusion imaging in patients with end-stage renal disease

BACKGROUND

The prognostic value of regadenoson SPECT myocardial perfusion imaging (MPI) has not been specifically studied in patients with end-stage renal disease (ESRD).

METHODS AND RESULTS

We prospectively followed ESRD patients enrolled in the ASSUAGE and ASSUAGE-CKD trials in which they received regadenoson-stress 99mTc-tetrofosmin SPECT-MPI. Images were semiquantitatively analyzed by an investigator blinded to clinical and outcome data. Patients were followed for cardiac death, myocardial infarction (MI), and coronary revascularization (CR). Revascularizations occurring >90 days post-MPI were considered "late" events. Survival analysis was performed using Cox regression models, adjusting for age, gender, diabetes, dyslipidemia, smoking, and known coronary artery disease. We analyzed 303 patients (mean age 54 years; 64% men), who were followed for 35 ± 10 months. Adjusting for clinical covariates, abnormal regadenoson-stress MPI (SSS ≥ 4) was associated with increased risk of the composite of cardiac death or MI (23.9% vs 14.4%; HR 1.88; CI 1.04-3.41; P = .037) and the composite of cardiac death, MI, or late CR (27.3% vs 16.7%; HR 1.80; CI 1.03-3.14; P = .039). Adjusting for clinical covariates, regadenoson-induced myocardial ischemia (SDS ≥ 2) was associated with increased rate of the composite endpoint of cardiac death, MI, or CR (33.3% vs 16.9%; HR 1.97; CI 1.19-3.27; P = .008).

CONCLUSION

Regadenoson-stress SPECT-MPI provides a significant prognostic value in patients with ESRD. ESRD patients with normal SPECT-MPI have relatively high adverse event rates.

Prognostic Utility of Calcium Scoring as an Adjunct to Stress Myocardial Perfusion Scintigraphy in End-Stage Renal Disease

Coronary artery calcium score (CACS) is a strong predictor of adverse cardiovascular events in the general population. Recent data confirm the prognostic utility of single-photon emission computed tomographic (SPECT) imaging in end-stage renal disease, but whether performing CACS as part of hybrid imaging improves risk prediction in this population is unclear. Consecutive patients (n = 284) were identified after referral to a university hospital for cardiovascular risk stratification in assessment for renal transplantation. Participants underwent technetium-99m SPECT imaging after exercise or standard adenosine stress in those unable to achieve 85% maximal heart rate; multislice CACS was also performed (Siemens Symbia T16, Siemens, Erlangen, Germany). Subjects with known coronary artery disease (n = 88) and those who underwent early revascularization (n = 2) were excluded. The primary outcome was a composite of death or first myocardial infarction. An abnormal SPECT perfusion result was seen in 22% (43 of 194) of subjects, whereas 45% (87 of 194) had at least moderate CACS (>100 U). The frequency of abnormal perfusion (summed stress score ≥4) increased with increasing CACS severity (p = 0.049). There were a total of 15 events (8 deaths, and 7 myocardial infarctions) after a median duration of 18 months (maximum follow-up 3.4 years). Univariate analysis showed diabetes mellitus (Hazard ratio [HR] 3.30, 95% CI 1.14 to 9.54; p = 0.028), abnormal perfusion on SPECT (HR 5.32, 95% CI 1.84 to 15.35; p = 0.002), and moderate-to-severe CACS (HR 3.55, 95% CI 1.11 to 11.35; p = 0.032) were all associated with the primary outcome. In a multivariate model, abnormal perfusion on SPECT (HR 4.18, 95% CI 1.43 to 12.27; p = 0.009), but not moderate-to-severe CACS (HR 2.50, 95% CI 0.76 to 8.20; p = 0.130), independently predicted all-cause death or myocardial infarction. The prognostic value of CACS was not incremental to clinical and SPECT perfusion data (global chi-square change = 2.52, p = 0.112). In conclusion, a perfusion defect on SPECT is an independent predictor of adverse outcome in potential renal transplant candidates regardless of the CACS. The use of CACS as an adjunct to SPECT perfusion data does not provide incremental prognostic utility for the prediction of mortality and nonfatal myocardial infarction in end-stage renal disease.

The prognostic value of regadenoson myocardial perfusion imaging

BACKGROUND

Regadenoson (REGA), a selective adenosine A2A receptor agonist, is the most widely used stress agent for SPECT myocardial perfusion imaging (MPI) in the United States. The diagnostic accuracy of REGA MPI is comparable to Adenosine MPI, but its prognostic value is not well defined.

METHODS

We categorized 1,400 patients (700 consecutive normal and 700 consecutive abnormal REGA-MPIs) into 4 groups based on the perfusion defect size using automated quantitative analysis: Group 1: normal perfusion; Group 2: <10% of left ventricle; Group 3: 10%-20%; Group 4: >20%. The primary outcome was a composite of cardiac death, myocardial infarction (MI), and late coronary revascularization (CR >90 days after MPI).

RESULTS

Of the 1,400 patients (42% male, 37% diabetes, 21% heart failure, 26% end-stage renal disease), the primary outcome occurred in 23% (17% cardiac death, 4% MI, 6% late CR) during 46 ± 18 months of follow-up and 8% had early CR (within 90 days of MPI). Early CR occurred in 0.4%, 9%, 17%, and 17% and the primary outcome in 10%, 27%, 31%, and 43% in Groups 1-4, respectively (P < .001 for both). In an adjusted Cox proportional model, the hazard ratio for the primary outcome was 2.68 (1.77-4.06), 3.32 (2.28-4.83), and 4.05 (2.78-5.91) for Groups 2-4 compared to Group 1.

CONCLUSION

REGA MPI provides powerful prognostic information that has important implications in patient management and can guide clinical practice.

Regadenoson provides perfusion results comparable to adenosine in heterogeneous patient populations: a quantitative analysis from the ADVANCE MPI trials

BACKGROUND

Total and reversible left ventricular (LV) perfusion defect size (PDS) predict patient outcome. Limited data exist as to whether regadenoson induces similar perfusion abnormalities as observed with adenosine. We sought to determine whether regadenoson induces a similar LV PDS as seen with adenosine across varying patient populations.

METHODS AND RESULTS

ADVANCE MPI were prospective, double-blind randomized trials comparing regadenoson to standard adenosine myocardial perfusion tomography (SPECT). Following an initial adenosine SPECT, patients were randomized to either regadenoson (N = 1284) or a second adenosine study (N = 660). SPECT quantification was performed blinded to randomization and image sequence. Propensity analysis was used to define comparability of regadenoson and adenosine perfusion results. Baseline clinical and SPECT results were similar in the two randomized groups. There was a close correlation between adenosine and regadenoson-induced total (r (2) = 0.98, P < .001) and reversible (r (2) = 0.92, P < .001) PDS. Serial differences in total (0.00 ± 3.51 vs -0.11 ± 3.46, P = .51) and reversible (0.15 ± 3.79 vs 0.07 ± 3.33, P = .65) PDS were also comparable in patients randomized to regadenoson vs adenosine, respectively, and irrespective of age, gender, diabetic status, body mass index, or prior cardiovascular history. By propensity analysis, regadenoson-induced total PDS was significantly larger than observed with adenosine.

CONCLUSION

This is the first study to show that regadenoson induces similar, if not larger, perfusion defects than those observed with adenosine across different patient populations and demonstrates the value of quantitative analysis for defining serial changes in SPECT perfusion results. Regadenoson should provide comparable diagnostic and prognostic SPECT information to that obtained with adenosine.

Coronary Artery Calcium Assessment in CKD: Utility in Cardiovascular Disease Risk Assessment and Treatment?

Coronary artery calcification (CAC) is a strong predictor of cardiovascular event rates in the general population, and scoring with multislice computed tomography commonly is used to improve risk stratification beyond clinical variables. CAC is accelerated in chronic kidney disease, but this occurs as a result of 2 distinct pathologic processes that result in medial (arteriosclerosis) and intimal (atherosclerosis) deposition. Although there are data that indicate that very high CAC scores may be associated with increased risk of death in hemodialysis, average CAC scores in most patients are elevated at a level at which discriminatory power may be reduced. There is a lack of data to guide management strategies in these patients based on CAC scores. There are even fewer data available for nondialysis patients, and it is uncertain whether CAC score confers an elevated risk of premature cardiovascular morbidity and mortality in such patients. In this article, we review the evidence regarding the utility of CAC score for noninvasive cardiovascular risk assessment in individuals with chronic kidney disease, using a clinical vignette that highlights some of the limitations in using CAC score and considerations in risk stratification.

Myocardial Ischemia Assessment in Chronic Kidney Disease: Challenges and Pitfalls

Coronary artery disease is the leading cause of mortality and morbidity in the chronic kidney disease (CKD) population and often presents with atypical symptoms. Current diagnostic investigations of myocardial ischemia in CKD lack sensitivity and specificity or may have adverse effects. We present a case vignette and explore the challenges of diagnostic myocardial stress investigation in patients with CKD.