Ongoing, silent, vaso-occlusion can culminate in vaso-occlusive crises (VOCs)—the clinical hallmark of sickle cell disease—which are unpredictable and painful events (also called vaso-occlusive events) that can lead to medical intervention.1-3


VOCs May Be Only the Tip of the Ongoing Vaso-Occlusion Iceberg1,2


Many Patients Manage Their VOCs at Home4

It has been reported that:
79% of VOCs are treated at home4*


Many patients manage their VOCs at home, and do not seek the medical attention they need.4

* According to PiSCES (Pain in Sickle Cell Epidemiology Study), in which 232 adults with sickle cell disease completed daily pain diary logs, home management of pain episodes constituted about 13% of the total days; whereas, use of health care facilities constituted less than 4% of the total days.4


Multicellular adhesion caused by chronic vascular inflammation promotes vaso-occlusion and VOCs.5,6



1. Inflammation and Cell Activation5,8

The blood vessels of patients with SCD are in a chronic state of inflammation because of activated endothelial cells of the blood vessel wall. Over time, hemolysis can exacerbate chronic vascular inflammation and cell activation. Endothelial and blood cell activation can lead to increased expression of adhesion mediators, resulting in multicellular adhesion

2. Multicellular Adhesion5

Activated cells and chronic inflammation initiate a complex cascade of cell interactions leading to upregulation of adhesion mediators. That drives multicellular adhesion among endothelial cells, WBCs, sickled RBCs, and platelets, thus promoting ongoing vaso-occlusion and VOCs

Do you know why multicellular adhesion is a major driver of VOCs?

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3. Vaso-Occlusion and VOCs2,6

Multicellular adhesion drives ongoing, silent, vaso-occlusion that can culminate in VOCs, also known as sickle cell pain crises, the clinical hallmark of SCD

4. Tissue and Organ Damage2,3

Ongoing, silent, vaso-occlusion and VOCs are associated with increased risk of organ damage, multiorgan failure, and death

SCD has diverse clinical manifestations and may affect organs throughout the body.3

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Vaso-occlusion and its resulting VOCs may account for a majority of the burden of sickle cell disease. Most of these events occur at home and are not reported. VOCs can impact patient quality of life and may increase the risk of organ damage; they are associated with higher mortality.2-4 


Survival of Patients with SCD by Number of VOCs/Year9


Increased Number of VOCs Per Year May Be Associated With Disease Progression and Increased Risk of Death9


This analysis included 542 adult subjects diagnosed with SCD who were routinely monitored in clinics at the Duke University Medical Center, Durham, NC; UNC Health Care System, Chapel Hill, NC; and Grady Health System, Atlanta, GA.9

  • VOCs were defined as crises requiring inpatient admission9
  • Median survival was 61 years for patients with 0-4 VOCs per year and 53 years for patients with >4 VOCs per year. Hazard ratio was 3.6982 (P<.0001)9


Vaso-Occlusive Crises Can Impact the Lives of Both Patients and Their Caregivers

VOCs are associated with decreased quality of life and increased risk of organ damage, multiorgan failure, and death3,7,10

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VOCs are the primary reason for emergency room (ER) visits and hospital admissions in patients with SCD10,12

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SCD and the burden of VOCs can affect social relationships, employment, and education13,14

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1. Puri L, Nottage KA, Hankins JS, Anghelescu DL. State of the art management of acute vaso-occlusive pain in sickle cell disease. Paediatr Drugs. 2018;20(1):29-42. 
2. Ballas SK, Gupta K, Adams-Graves P. Sickle cell pain: a critical reappraisal. Blood. 2012;120(18):3647-3656. 3. Piel FB, Steinberg MH, Rees DC. Sickle cell disease. N Engl J Med. 2017;376(16):1561-1573. 
4. Smith WR, Pemberthy LT, Bovbjerg VE, et al. Daily assessment of pain in adults with sickle cell disease. Ann Intern Med. 2008;148(2):94-101. 
5. Zhang D, Xu C, Manwani D, Frenette PS. Sickle cell disease: challenges and progress. Neutrophils, platelets, and inflammatory pathways at the nexus of sickle cell disease pathophysiology. Blood. 2016;127(7):801-809. 
6. Puri L, Nottage KA, Hankins JS, Anghelescu DL. State of the art management of acute vaso-occlusive pain in sickle cell disease. Paediatr Drugs. 2018;20(1):29-42. 
7. Conran N, Franco-Penteado CF, Costa FF. Newer aspects of the pathophysiology of sickle cell disease vaso-occlusion. Hemoglobin. 2009;33(1):1-16. 
8. Kanter J, Kruse-Jarres R. Management of sickle cell disease from childhood through adulthood. Blood Rev. 2013;27(6):279-287. 
9. Elmariah H, Garrett ME, De Castro LM, et al. Factors associated with survival in a contemporary adult sickle cell disease cohort. Am J Hematol. 2014;89(5):530-535. 
10. American Society of Hematology. State of Sickle Cell Disease: 2016 Report. Washington, DC: 2016. 
11. Lentz MB, Kautz DD. Acute vaso-occlusive crisis in patients with sickle cell disease. Nursing2018. 2017;41(1):67-68. 
12. Ballas SK, Lusardi M. Hospital readmission for adult acute sickle cell painful episodes: frequency, etiology, and prognostic significance. Am J Hematol. 2005;79(1):17-25. 
13. Swanson ME, Grosse SD, Kulkarni R. Disability among individuals with sickle cell disease. Am J Prev Med. 2011;41(6S4):S390-S397. 
14. Brandow AM, Brousseau DC, Panepinto JA. Post-discharge pain, functional limitations, and impact on caregivers of children with sickle cell disease treated for painful events. Br J Haematol. 2009;144(5):782-788.


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