The prognostic value of positron emission tomography in the evaluation of suspected cardiac sarcoidosis.

OBJECTIVES: To assess the prognostic value of positron emission tomography (PET) imaging in patients undergoing evaluation for known or suspected cardiac sarcoidosis (CS) while not on active immunotherapy. BACKGROUND: Previous studies have attempted to identify the value of PET imaging to aid in risk stratification of patients with CS, however, most cohorts have included patients currently on immunosuppression, which may confound scan results by suppressing positive findings. METHODS: We retrospectively analyzed 197 patients not on immunosuppression who underwent 18F-fluorodeoxyglucose (FDG) PET scans for evaluation of known or suspected CS. The primary endpoint of the study was time to ventricular arrhythmia (VT/VF), or death. Candidate predictors were identified by univariable Cox proportional hazards regression. Independent predictors were identified by performing multivariable Cox regression with stepwise forward selection. RESULTS: Median follow-up time was 531 [IQR 309, 748] days. 41 patients met the primary endpoint. After stepwise forward selection, left ventricular ejection fraction (LVEF) (HR 0.98, 95% CI 0.96-0.99, P = 0.02), history of VT/VF (HR 4.19, 95% CI 2.15-8.17, P < 0.001), and summed rest score (SRS) (HR 1.06, 95% CI 1.02-1.12, P = 0.01) were predictive of the primary endpoint. Quantitative and qualitative measures of FDG uptake on PET were not predictive of clinical events. CONCLUSIONS: Among untreated patients who underwent PET scans to evaluate known or suspected CS, LVEF, history of VT/VF, and SRS were associated with adverse clinical outcomes.

Initial clinical experience of N13-ammonia myocardial perfusion PET/CT using a compact superconducting production system.

BACKGROUND: Although N13-ammonia has favorable properties among FDA approved radiotracers, complexity of implementation has limited its use. We describe the initial patient experience of N13-ammonia PET imaging using a compact N13-ammonia production system. METHODS: N13 was produced using the ION-12SC, a 12MeV, 10uA superconducting minimally shielded cyclotron, and reduced to N13-ammonia in an automated multi-use purification unit. Patients were power injected with 9.3 ± 1.1 mCi (344.1 ± 40.7 MBq) of N13-ammonia for rest imaging, and 18.8 ± 0.9 mCi (695.6 ± 33.3 MBq) of N13-ammonia was injected at peak hyperemia for stress testing. Images were interpreted for relative perfusion, left ventricular volumes/function, blood flow quantification, and scored for image quality. RESULTS: In total 97 patients underwent 98 N13-ammonia PET scans (32 rest only/65 rest-stress/1 stress only). Image quality was 91.8% good or excellent. None were poor/non-diagnostic. Study durations were acceptable. Tracer related radiation dosimetry to patients was 0.7 ± 0.1 mSv (rest only), and 2.1 ± 0.1 mSv (rest-stress). CONCLUSION: Clinical N13-ammonia production by the Ionetix ION-12SC delivers high quality myocardial PET perfusion images in a rapid protocol.

Assessing the utility of pre-operative first pass radionuclide angiography to predict right ventricular failure post left ventricular assist device implantation.

INTRODUCTION: Right ventricular failure (RVF) after left ventricular assist device (LVAD) placement is associated with worse outcomes. We hypothesized that decreased right ventricular (RV) ejection fraction (EF) as well as qualitative assessments of RV function and dilation, as assessed by first pass radionuclide angiography (FPRNA), are associated with an increased risk of RVF following LVAD implantation. METHODS: We retrospectively identified 46 patients from 1/2008 to 11/2017 that underwent FPRNA and LVAD implantation. RVF was defined as requiring inotropes for greater than 14 days after LVAD implantation or requiring a right ventricular assist device. FPRNA-derived variables of RV performance and structure were compared between those that did and did not have RVF post implant. Statistical analyses were performed with Mann-Whitney U tests for ordinal and continuous variables. Fisher's exact tests and Pearson's χ2 tests were used for categorical variables. RESULTS: Eight patients developed RVF after device implantation. The average RV EF on FPRNA was 41.45% in those that did not develop RVF and 40.13% in those that did (P = 0.787). RV dilation (P = 0.896) and global RV function (P = 0.827) by FPRNA were not statistically different between the two groups. CONCLUSION: In patients that required FPRNA for further assessment of RV function prior to LVAD implantation, decreased RV EF, RV dilation and global RV function on FPRNA were not associated with an increased risk of RVF.

COVID-19 Outcomes Among Solid Organ Transplant Recipients: A Case-control Study.

BACKGROUND: Solid organ transplant (SOT) recipients are considered to be "vulnerable" to COVID-19 infection due to immunosuppression. To date, there are no studies that compared the disease severity of COVID-19 in SOT recipients with nontransplant patients. METHODS: In this case-control study, we compared the outcomes of COVID-19 between SOT recipients and their matched nontransplant controls. The cases were all adult SOT recipients (N = 41) from our academic health center who were diagnosed with COVID-19 between March 10, 2020 and May 15, 2020 using positive reverse transcriptase polymerase chain reaction for SARS-CoV2. The controls (N = 121) were matched on age (±5 y), race, and admission status (hospital or outpatient). The primary outcome was death and secondary outcomes were severe disease, intubation and renal replacement therapy (RRT). RESULTS: Median age of SOT recipients (9 heart, 3 lung, 16 kidney, 8 liver, and 5 dual organ) was 60 y, 80% were male and 67% were Black. Severe disease adjusted risk of death was similar in both the groups (hazard ratio = 0.84 [0.32-2.20]). Severity of COVID-19 and intubation were similar, but the RRT use was higher in SOT (odds ratio = 5.32 [1.26, 22.42]) compared to non-SOT COVID-19 patients. Among SOT recipients, COVID-19-related treatment with hydroxychloroquine (HCQ) was associated with 10-fold higher hazard of death compared to without HCQ (hazard ratio = 10.62 [1.24-91.09]). CONCLUSIONS: Although African Americans constituted one-tenth of all SOT in our center, they represented two-thirds of COVID-19 cases. Despite high RRT use in SOT recipients, the severe disease and short-term death were similar in both groups. HCQ for the treatment of COVID-19 among SOT recipients was associated with high mortality and therefore, its role as a treatment modality requires further scrutiny.

Diagnostic Accuracy of FDG PET/CT in Suspected LVAD Infections: A Case Series, Systematic Review, and Meta-Analysis.

OBJECTIVES: The purpose of this study was to describe our experience with fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography computed tomography (PET/CT) in diagnosing left ventricular assist device (LVAD) infections and perform a meta-analysis of published studies to determine overall diagnostic accuracy. BACKGROUND: Device-related infections are a common complication of LVADs and are linked to worse outcomes. Diagnosis of LVAD infections remains challenging. FDG PET/CT has demonstrated good diagnostic accuracy in several other infectious conditions. METHODS: This was a single-center, retrospective case series of FDG PET/CT scans in suspected LVAD infection between September 2015 and February 2018. A systematic review of PubMed from database inception through March 2018 was also conducted to identify additional studies. RESULTS: Nineteen FDG PET/CT scans were identified for the retrospective case series. The systematic review identified an additional 3 publications, for a total of 4 studies involving 119 scans assessing diagnostic performance. Axial (n = 36) and centrifugal (n = 83) flow LVADs were represented. Pooled sensitivity was 92% (95% confidence interval [CI]: 82% to 97%) and specificity was 83% (95% CI: 24% to 99%) for FDG PET/CT in diagnosing LVAD infections. Summary receiver-operating characteristic curve analysis demonstrated an AUC of 0.94 (95% CI: 0.91 to 0.95). CONCLUSIONS: FDG PET/CT for suspected LVAD infections demonstrates good diagnostic accuracy, with overall high sensitivity but variable specificity.

Association of Holter-Derived Heart Rate Variability Parameters With the Development of Congestive Heart Failure in the Cardiovascular Health Study.

OBJECTIVES: This study sought to determine whether Holter-based parameters of heart rate variability (HRV) are independently associated with incident heart failure among older adults in the CHS (Cardiovascular Health Study) as evidenced by an improvement in the predictive power of the Health Aging and Body Composition Heart Failure (Health ABC) score. BACKGROUND: Abnormal HRV, a marker of autonomic dysfunction, has been associated with multiple adverse cardiovascular outcomes but not the development of congestive heart failure (CHF). METHODS: Asymptomatic CHS participants with interpretable 24-h baseline Holter recordings were included (n = 1,401). HRV measures and premature ventricular contraction (PVC) counts were compared between participants with (n = 260) and without (n = 1,141) incident CHF on follow-up. Significantly different parameters between groups were added to the components of the Health ABC score, a validated CHF prediction tool, using stepwise Cox regression. RESULTS: The final model included components of the Health ABC score, In PVC counts (adjusted hazard ratio [aHR]: 1.12; 95% confidence interval [CI]: 1.07 to 1.19; p < 0.001) and the following HRV measures: abnormal heart rate turbulence onset (aHR: 1.52; 95% CI: 1.11 to 2.08; p = 0.009), short-term fractal scaling exponent (aHR: 0.27; 95% CI: 0.14 to 0.53; p < 0.001), in very low frequency power (aHR: 1.28; 95% CI: 1.02 to 1.60; p = 0.037), and coefficient of variance of N-N intervals (aHR: 0.94; 95% CI: 0.90 to 0.99; p = 0.009). The C-statistic for the final model was significantly improved over the Health ABC model alone (0.77 vs. 0.73; p = 0.0002). CONCLUSIONS: Abnormal HRV parameters were significantly and independently associated with incident CHF in asymptomatic, older adults. When combined with increased PVCs, HRV improved the predictive power of the Health ABC score.