Background Cardiovascular disease is an important cause of morbidity and mortality in sickle cell disease (SCD). We sought to characterize sickle cell cardiomyopathy using multi-modality non-invasive cardiovascular testing and identify potential causative mechanisms. Methods and Results Stable adults with SCD (n=38) and healthy controls (n=13) prospectively underwent same day multi-parametric cardiovascular magnetic resonance (cine, T2* iron, vasodilator first pass myocardial perfusion, and late gadolinium enhancement (LGE) imaging), transthoracic echocardiography, and applanation tonometry. Compared to controls, patients with SCD had severe dilation of the left ventricle (124±27 vs 79±12 ml/m2), right ventricle (127±28 vs 83±14 ml/m2), left atrium (65±16 vs 41±9 ml/m2), and right atrium (78±17 vs 56±17 ml/m2), p<0.01 for all. SCD patients also had a 21% lower myocardial perfusion reserve index than control subjects (1.47±0.34 vs 1.87±0.37, p=0.034). A significant subset of SCD patients (25%) had evidence of LGE while only one patient had evidence of myocardial iron overload. Diastolic dysfunction was present in 26% of SCD patients compared to 8% in controls. Estimated filling pressures (E/e’, 9.3±2.7 vs 7.3±2.0, p=0.0288) was higher in SCD patients. Left ventricular dilation and the presence of LGE were inversely correlated to hepatic T2* times (i.e. hepatic iron overload due to frequent blood transfusions, p<0.05 for both); whereas, diastolic dysfunction and increased filling pressures were correlated to aortic stiffness (augmentation pressure and index, p<0.05 for all). Conclusions Sickle cell cardiomyopathy is characterized by 4-chamber dilation and in some patients myocardial fibrosis, abnormal perfusion reserve, diastolic dysfunction, and only very rarely myocardial iron overload. Left ventricular dilation and myocardial fibrosis are associated with increased blood transfusion requirements while left ventricular diastolic dysfunction is predominantly correlated with increased aortic stiffness.

BackgroundRegadenoson is a vasodilator stress agent that selectively activates the A2A receptor. Compared to adenosine, regadenoson is easier to administer and results in fewer side effects. Although extensively studied in patients undergoing nuclear perfusion imaging (MPI), its use for perfusion cardiovascular magnetic resonance (CMR) is not well described. The aim of this study was to determine the prognostic value of a normal regadenoson perfusion CMR in patients with known or suspected coronary artery disease.MethodsPatients with known or suspected coronary artery disease were prospectively enrolled to receive perfusion CMR (Philips 1.5 T) with regadenoson. Three short-axis slices of the left ventricle (LV) were obtained during first pass of contrast using a hybrid GRE-EPI pulse sequence (0.075 mmol/kg Gadolinium-DTPA-BMA at 4 ml/sec). Imaging was performed 1 minute after injection of regadenoson (0.4 mg) and repeated 15 minutes after reversal of hyperemia with aminophylline (125 mg). Perfusion defects were documented if they persisted for ≥2 frames after peak enhancement of the LV cavity. CMR was considered abnormal if there was a resting wall motion abnormality, decreased LVEF (<40%), presence of LGE, or the presence of a perfusion defect during hyperemia. All patients were followed for a minimum of 1 year for major adverse cardiovascular event (MACE) defined as coronary revascularization, non-fatal myocardial infarction, and cardiovascular death.Results149 patients were included in the final analysis. Perfusion defects were noted in 43/149 (29%) patients; 59/149 (40%) had any abnormality on CMR. During the mean follow-up period of 24 ± 9 months, 17/149 (11.4%) patients experienced MACE. The separation in the survival distributions for those with perfusion defects and those without perfusion defects was highly significant (log-rank p = 0.0001). When the absence of perfusion defects was added to the absence of other resting CMR abnormalities, the negative predictive value improved from 96% to 99%.ConclusionRegadenoson perfusion CMR provides high confidence for excellent prognosis in patients with normal perfusion.

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