Contributions
Abstract: EP1221
Type: E-Poster Presentation
Session title: Sickle cell disease
Background
Sickle cell disease (SCD) is recognized as a hypercoagulable state and associated with an increased incidence of thromboembolic events. SCD patients presenting with vaso-occlusive crisis (VOC) frequently have symptoms also suspected of pulmonary embolism (PE) (i.e. thoracic pain, dyspnea, decreased O2 saturation). To compute the pretest probability of PE, the YEARS decision rule is used. This algorithm uses the presence of three clinical criteria (1. signs of deep venous thrombosis, 2. Hemoptysis, 3. PE most probable diagnosis) in combination with D-dimer cut off values. A D-dimer level of ≥ 0.5 mg/L (and 1 or more positive criteria), or ≥ 1mg/L (and no positive criteria) indicates a high probability of PE and would justify performing a computed tomography pulmonary angiogram (CTPA) for a definitive diagnosis. Being a hypercoagulable disease, SCD is associated with increased D-dimer levels. The YEARS decision rule is not validated for SCD patients.
We questioned whether the use of the YEARS criteria with its current D-dimer cut off values is able to rule out PE in SCD patients.
Aims
To validate the Years criteria with its current D-dimer cut off values to rule out PE in SCD patients.
Methods
We performed a single-center retrospective cohort study in the Amsterdam University Medical Centres, a tertiary hospital in the Netherlands. Consecutive D-dimer samples of patients (≥18y) with a confirmed diagnosis of SCD and sickle cell trait (HbAS) were eligible for inclusion if D-dimers were measured to exclude suspected PE. D-dimer samples that were measured to exclude deep venous thrombosis or in other settings were excluded. Laboratory values including D-dimer levels, medical history, the proportion of indicated CTPA examinations based on the YEARS decision rule, the incidence of PE and other diagnoses were documented and compared between groups.
Results
A total of 76 patients with 94 D-dimer samples were eligible for inclusion. Sixty (79%) participants had SCD, while 16 (21%) had HbAS. Plasma D-dimer levels were significantly higher in SCD patients compared to individuals with HbAS (2.88 mg/L [1.56-4.43] vs. 1.01 mg/L [0.49-4.03]; P=0.004). Sixty-seven (89%) of SCD patients and 10 (53%) of individuals with HbAS had D-dimer levels in excess of 1,0 mg/L. In patients with the severe genotype (HbSS and HbS-β0-thalassemia), 94% had D-dimer levels ≥ 1.0 mg/L. CTPA was performed in 88% of SCD patients and 69% of individuals with HbAS. PE was confirmed in 8 (9%) patients without significant differences between patients with SCD and those with HbAS (n=5 (7%) vs n=3 (16%); P=0.203, respectively). No differences in D-dimer levels were found in SCD patients with PE compared to those without PE (3.62 mg/L [2.54-8.59] vs 2.76 mg/L [1.52-4.39), P=0.293).
Conclusion
In this study, 89% of analyzed D-dimer values in SCD patients were > 1 mg/L. This was 94% for the severe genotypes. This translated into a high percentage of CTPA that then had a low yield (7%) of PE in SCD patients. The rate of indication for CTPA for SCD patients in this study was much higher than the 20-30% previously reported for the YEARS algorithm. These data indicate that the specificity of the YEARS algorithm is very low in SCD patients and might lead to over imaging in this patient group.
Keyword(s): D-dimer, Pulmonary embolism, Sickle cell disease
Abstract: EP1221
Type: E-Poster Presentation
Session title: Sickle cell disease
Background
Sickle cell disease (SCD) is recognized as a hypercoagulable state and associated with an increased incidence of thromboembolic events. SCD patients presenting with vaso-occlusive crisis (VOC) frequently have symptoms also suspected of pulmonary embolism (PE) (i.e. thoracic pain, dyspnea, decreased O2 saturation). To compute the pretest probability of PE, the YEARS decision rule is used. This algorithm uses the presence of three clinical criteria (1. signs of deep venous thrombosis, 2. Hemoptysis, 3. PE most probable diagnosis) in combination with D-dimer cut off values. A D-dimer level of ≥ 0.5 mg/L (and 1 or more positive criteria), or ≥ 1mg/L (and no positive criteria) indicates a high probability of PE and would justify performing a computed tomography pulmonary angiogram (CTPA) for a definitive diagnosis. Being a hypercoagulable disease, SCD is associated with increased D-dimer levels. The YEARS decision rule is not validated for SCD patients.
We questioned whether the use of the YEARS criteria with its current D-dimer cut off values is able to rule out PE in SCD patients.
Aims
To validate the Years criteria with its current D-dimer cut off values to rule out PE in SCD patients.
Methods
We performed a single-center retrospective cohort study in the Amsterdam University Medical Centres, a tertiary hospital in the Netherlands. Consecutive D-dimer samples of patients (≥18y) with a confirmed diagnosis of SCD and sickle cell trait (HbAS) were eligible for inclusion if D-dimers were measured to exclude suspected PE. D-dimer samples that were measured to exclude deep venous thrombosis or in other settings were excluded. Laboratory values including D-dimer levels, medical history, the proportion of indicated CTPA examinations based on the YEARS decision rule, the incidence of PE and other diagnoses were documented and compared between groups.
Results
A total of 76 patients with 94 D-dimer samples were eligible for inclusion. Sixty (79%) participants had SCD, while 16 (21%) had HbAS. Plasma D-dimer levels were significantly higher in SCD patients compared to individuals with HbAS (2.88 mg/L [1.56-4.43] vs. 1.01 mg/L [0.49-4.03]; P=0.004). Sixty-seven (89%) of SCD patients and 10 (53%) of individuals with HbAS had D-dimer levels in excess of 1,0 mg/L. In patients with the severe genotype (HbSS and HbS-β0-thalassemia), 94% had D-dimer levels ≥ 1.0 mg/L. CTPA was performed in 88% of SCD patients and 69% of individuals with HbAS. PE was confirmed in 8 (9%) patients without significant differences between patients with SCD and those with HbAS (n=5 (7%) vs n=3 (16%); P=0.203, respectively). No differences in D-dimer levels were found in SCD patients with PE compared to those without PE (3.62 mg/L [2.54-8.59] vs 2.76 mg/L [1.52-4.39), P=0.293).
Conclusion
In this study, 89% of analyzed D-dimer values in SCD patients were > 1 mg/L. This was 94% for the severe genotypes. This translated into a high percentage of CTPA that then had a low yield (7%) of PE in SCD patients. The rate of indication for CTPA for SCD patients in this study was much higher than the 20-30% previously reported for the YEARS algorithm. These data indicate that the specificity of the YEARS algorithm is very low in SCD patients and might lead to over imaging in this patient group.
Keyword(s): D-dimer, Pulmonary embolism, Sickle cell disease