Impact of IV Contrast Exposure during Vaso-Occlusive Crisis on Sickle Cell Disease (SCD)

Background

Sickle cell disease (SCD) affects more than 100.000 Americans, that can experience vaso-occlusive crisis (VOC). It can present with signs and symptoms that overlap with pulmonary embolism (PE), e.g. pleuritic chest pain, shortness of breath, hypoxia or sinus tachycardia. Hence, it is not uncommon that patients with SCD are exposed routinely to IV contrast (IV-cx) to rule out PE with every VOC recurrence. We hypothesized that exposure to IV-cx increases blood viscosity temporarily and therefore exacerbates RBC sickling with worsening oxidative stress and VOC.

Methods

This was a retrospective chart review study, where we analyzed all encounters for VOC at the ED of MedStar Washington Hospital Center in between 2021-2022. We excluded those not admitted to the inpatient service and discharged from the ED, those not exposed to IV-cx to rule out PE and those without 3 other VOC admission without IV-cx exposure to compare as control. Herein, will discuss 33 patients’ results. A total of 132 admissions were analyzed for 33 patients (1 with IV-cx + 3 regular admissions without IV-cx exposure), each patient serving as their own controls, acknowledging the heterogeneity of SCD VOC. For control admissions we looked at the 3 closest in time from the admission with IV-cx exposure. Severity of each VOC (with or without IV-cx exposure) was determined by the composite of lab results, clinical and treatment data for each admission, creating our own scoring system “VOC Severity Index” (Table 1). Scores were given from 0-4, >3 representing end-organ damage. Maximum score was 39. Likewise, we collected data on new PE, new DVT, therapeutic anticoagulation, basic demographics and SCD genotype not recorded in the severity index score. Results were analyzed through Graphpad Prism software. This study received IRB approval from MedStar Health Research Institute.

Results

54.5% (18/33) were female, mean age was 25 (18-45), 86% were HbSS, and 100% were Black. We compared the severity index of the admission with IV-cx exposure against the mean severity index score of the 3 other VOC admissions without IV-cx exposure. VOC severity index was higher for the admission related with IV-cx exposure in 90% (30/33) patients (p= 0.0004***) (Fig 1A). CT chest with PE protocol was negative in 100% (33/33). No DVT was reported in the totality of 132 encounters. AKI was noted in 15.0% (5/33) of patients when IV-cx was used, vs 7.0% (7/99) when no IV-cx was used. Length of stay was not significantly different (p=0.436) (mean IV-cx stay: 8 days vs. mean non-IV cx stay: 7.8 days). RBCs exchange transfusion happened in 10% of total encounters analyzed (14/132), being 42% (6/14) of the situations when IV-cx was used. Acute chest syndrome (ACS) developed in 19 admissions of 10 patients (6 female/4 male). Interestingly, 42% (8/19) of ACS happened when IV contrast had been used, and only 7/19 were managed with RBC exchange transfusion. In 1 encounter with IV-cx exposure, patient developed acute chest syndrome and ARDS requiring ECMO, (end-organ damage not reflected in our severity index score). VOC Severity Index means were similar in female vs male patients. Likewise, gender was not related to higher frequency of AKI, exchange transfusion or length of stay.

Conclusions

IV-cx exposure is associated with worsening in the severity of the VOC, manifested as more severe pain, and need of escalation of treatments, albeit with no increase in the LOS. Iv-cx should be avoided in SCD patients in VOC, when possible. PE should remain low in the differential in the setting of VOC, despite overlapping symptoms. Our findings are limited in the nature of retrospective chart review and small number of patients. Further analysis with prospective larger cohorts are needed for a better understanding on the role of IV-cx exposure, sickle cell renal disease and VOC.