Optimal left ventricular ejection fraction in risk stratification of patients with cardiac sarcoidosis

Prognostic value of multimodality imaging in the contemporary management of cardiac sarcoidosis

BACKGROUND

Echocardiography, cardiac magnetic resonance and cardiac 18fluorodeoxyglucose positron emission tomography (FDG-PET) imaging play key roles in the diagnosis and management of cardiac sarcoidosis (CS), but the relative value of each modality in predicting outcomes has yet to be determined. This study sought to determine the prognostic importance of multimodality imaging data over and above demographic characteristics and left ventricular ejection fraction (LVEF).

METHODS

Consecutive patients newly diagnosed with CS were included. Parameters evaluated included echocardiographic regional wall motion abnormality (RWMA), myocardial strain, LVEF, right ventricular ejection fraction (RVEF), late gadolinium enhancement (LGE) extent, SUVmax and RV FDG uptake. The primary endpoint was a composite of all-cause mortality and serious ventricular arrhythmia.

RESULTS

The study population consisted of 208 patients with mean age of 55±13 years and LVEF of 55±12%. During a median follow-up period of 46 (IQR: 18-55) months, 14 patients died and 28 suffered serious ventricular arrhythmias. On multivariable analysis, RWMA (HR for RWMA presence 2.55, 95% CI 1.27 to 5.28, p=0.008), LGE extent (HR per 1% increase 1.02, 95% CI 1.00 to 1.04, p=0.018), RVEF (HR per 1% decrease 0.97, 95% CI 0.94 to 0.99, p=0.008) and RV FDG uptake (HR for RV FDG presence 2.48, 95% CI 1.15 to 5.33, p=0.020) were independent predictors of the primary endpoint, while LVEF was not predictive. The risk of adverse events was significantly greater in those with LGE extent ≥15% (HR for ≥15% presence 3.96, 95% CI 2.17 to 7.23, p<0.001).

CONCLUSION

In our CS population, RWMA, LGE extent, RVEF and RV FDG uptake were strong independent predictors of an adverse outcome. These findings offer an important insight into the key multimodality imaging parameters that may be used in a future risk stratification model of patients with CS.

Discordant cardiac inflammation between 18F-FDG PET and CMR in patients with cardiac sarcoidosis

Current diagnostic criteria for cardiac sarcoidosis (CS) rely on non-invasive imaging tools including positron emission tomography (PET-CT) and cardiac magnetic resonance (CMR). The aim of this study was to assess the prevalence of discordant myocardial inflammation between PET-CT and CMR in patients with known cardiac sarcoidosis. We retrospectively identified patients with both 18F-FDG PET-CT and CMR who had histology-proven sarcoidosis (N = 148). Among these 25 (17%) had abnormal 18F-FDG metabolism with normal tissue characterization by CMR. Of these, 13 (9%) had the studies concomitantly within 180 days (median 5 days, IQR 1-31). During median follow up of 7 years, 3 (23%) deaths were documented. Although prospective studies are required to address the best imaging approach for cardiac inflammation, our observation that some patients with CS have evidence of disease activity on PET-CT, but not on limited CMR without mapping suggests that a negative limited CMR may not fully exclude CS.

Area-weighted unipolar voltage to predict heart failure outcomes in patients with ischaemic cardiomyopathy and ventricular tachycardia

AIMS

Patients with ischaemic cardiomyopathy (ICM) referred for catheter ablation of ventricular tachycardia (VT) are at risk for end-stage heart failure (HF) due to adverse remodelling. Local unipolar voltages (UV) decrease with loss of viable myocardium. A UV parameter reflecting global viable myocardium may predict prognosis. We evaluate if a newly proposed parameter, area-weighted unipolar voltage (awUV), can predict HF-related outcomes [HFO; HF death/left ventricular (LV) assist device/heart transplant] in ICM.

METHODS AND RESULTS

From endocardial voltage maps of consecutive patients with ICM referred for VT ablation, awUV was calculated by weighted interpolation of local UV. Associations between clinical and mapping parameters and HFO were evaluated and validated in a second cohort. The derivation cohort consisted of 90 patients [age 68 ±8 years; LV ejection fraction (LVEF) 35% interquartile range (IQR) (24-40)] and validation cohort of 60 patients [age 67 ± 9, LVEF 39% IQR (29-45)]. In the derivation cohort, during a median follow-up of 45 months [IQR (34-83)], 36 (43%) patients died and 23 (26%) had HFO. Patients with HFO had lower awUV [4.51 IQR (3.69-5.31) vs. 7.03 IQR (6.08-9.2), P < 0.001]. A reduction in awUV [optimal awUV (5.58) cut-off determined by receiver operating characteristics analysis] was a strong predictor of HFO (3-year HFO survival 97% vs. 57%). The cut-off value was confirmed in the validation cohort (2-year HFO-free survival 96% vs. 60%).

CONCLUSION

The newly proposed parameter awUV, easily available from routine voltage mapping, may be useful at identifying ICM patients at high risk for HFO.

Cardiac Sarcoidosis: A Comprehensive Clinical Review

Sarcoidosis is an inflammatory multisystemic disease of unknown etiology characterized by the formation of non-caseating granulomas. Sarcoidosis can affect any organ, predominantly the lungs, lymphatic system, skin and eyes. While > 90% of patients with sarcoidosis have lung involvement, an estimated 5% of patients with sarcoidosis have clinically manifest cardiac sarcoidosis (CS), whereas approximately 25% have asymptomatic, clinically silent cardiac involvement verified by autopsy or imaging studies. CS can present with conduction disturbances, ventricular arrhythmias, heart failure or sudden cardiac death. Approximately 30% of < 60-year-old patients presenting with unexplained high degree atrioventricular (AV) block or ventricular tachycardia are diagnosed with CS, therefore CS should be strongly considered in such patients. CS is the second leading cause of death among patients affected by sarcoidosis after pulmonary sarcoidosis, therefore its early recognition is important, because early treatment may prevent death from cardiovascular involvement. The establishment of isolated CS diagnosis sometimes can be quite difficult, when extracardiac disease cannot be verified. The other reason for the difficulty to diagnose CS is that CS is a chameleon of cardiology and it can mimic (completely or almost completely) different cardiac diseases, such as arrhythmogenic cardiomyopathy, giant cell myocarditis, dilated, restrictive and hypertrophic cardiomyopathies. In this review article we will discuss the current diagnosis and management of CS and delineate the potential difficulties and pitfalls of establishing the diagnosis in atypical cases of isolated CS.

Standardized ketogenic dietary preparation for metabolic PET imaging in suspected and known cardiac sarcoidosis

Aims

A major limitation of cardiac positron emission tomography (PET) with F18-fluorodeoxyglucose (F18-FDG) for the evaluation of cardiac sarcoidosis (CS) is associated with physiologic myocardial glucose uptake. The optimal dietary protocol to suppress physiologic myocardial F18-FDG uptake is not well-established. We aimed to evaluate the diagnostic performance of a novel dietary preparation using a ketone-based infant formula.

Methods and results

Between 2018 and 2021, consecutive studies using a ketogenic dietary preparation were identified (n = 198). The rate of non-diagnostic studies due to failure to suppress myocardial glucose was 7.1% (n = 14) with a similar incidence in diabetics (n = 6, 8.1%). Among studies reported to have no inflammation (n = 137), 130 studies (66%) had mean myocardial standardized uptake value (SUV) less than or equal to mean blood pool SUV.

Conclusion

Patient preparation with a ketone-based infant formula resulted in low rate of inappropriate myocardial glucose suppression in patients undergoing F18-FDG cardiac PET to evaluate CS.