Myocardial Ischemia in Patients with Sickle Cell Disease: A Retrospective Review

Introduction: On an autopsy study of 306 patients with sickle cell disease (SCD), cardiovascular disease is observed in 58% of patients and myocardial microinfarcts were noted in 20% of patients. Previously data from our center indicates that approximately 13% (3/22) patients demonstrated cardiac microvascular disease in steady state. However, the incidence of myocardial ischemic injury in patients with SCD presenting with chest pain remains largely undefined.

Methods: We conducted a single institution retrospective chart review from September 2009 through September 2014 to evaluate the incidence of elevated troponin-I (normal < 0.11ng/ml), which is a well-established biomarker of myocardial injury, in patients with SCD and chest pain. We further characterize each of these episodes with cardiac magnetic resonance imaging, if available, and clinical and laboratory findings at the time of the event. Kruskal-Wallis test was used to compare troponin measurement values among different groups of patients.

Results: A total of 25 (10 female, 15 male) of the 352 (7%) of patients followed at the Ohio State Comprehensive Sickle Cell Center had troponin elevation over a 5 year period. They had a total of thirty-eight individual encounters with troponin elevations (range: 0.11-12.17) [72% patients with 1 elevation, 28% patients multiple troponin elevations) (range: 1-4 incidences)]. The median age at the time of troponin elevation was 36 (Range: 20.5-66 yrs). Troponin elevation was observed in patients of all genotypes (76% SS; 4% SBeta⁺; 20% SC). 6/25 (25%) of patients with troponin elevation in the past five years are now deceased. Thirteen patients (52%) had acute chest syndrome and ten patients (40%) had acute kidney injury at the time of troponin elevation. The degree of troponin elevation was not associated with concurrent acute chest syndrome, concurrent acute kidney injury or mortality. At the encounter level, median troponin at diagnosis was 0.3 (range: 0.11-12.2) and the median peak troponin was 0.4 (range: 0.11-38.1),. The median value of TR jet velocity at baseline was 2.8 (range: 1.1-3.7) (n=23) and the median TR jet velocity at the time of elevation was 3.0 (range: 1.7-4.6) (n=28). Median baseline hemoglobin was 8 (range: 4.5-12.6) and median hemoglobin at encounter was 7.5 (range: 4.3-12.5), resulting in a median change in hemoglobin of -0.4 (range: -6.2 - 2.5). Four of 10 MRI obtained at the time of troponin elevation showed myocardial ischemia and 3/10 patients showed late gadolinium enhancement indicating myocardial injury.

Conclusion: Patients with SCD presenting with chest pain have myocardial ischemia and infarctions as demonstrated in our population by both troponin elevation and cardiac imaging. While, the long term implications of this finding are currently being studied in a multi-centered prospective study, further cardiac evaluations should be considered in patients with SCD presenting with chest pain.