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Philippe Connes - One of the best experts on this subject based on the ideXlab platform.

  • rheology of red blood Cells in patients with hbC Disease
    Clinical Hemorheology and Microcirculation, 2016
    Co-Authors: Nathalie Lemonne, Xavier Waltz, Marc Romana, Maryse Etiennejulan, Philippe Connes, Marie Billaud, Regine Hierso
    Abstract:

    : Patients with Hemoglobin C Disease (CC) usually do not develop severe CompliCations in Comparison with individuals with siCkle Cell anemia (SS) or with siCkle Cell Hemoglobin C Disease (SC). The present study Compared the hematologiCal, bioChemiCal, hemorheologiCal and CliniCal CharaCteristiCs of CC patients to those of SS, SC and healthy individuals (AA). Blood visCosity was measured at 225 s(-1) with a Cone plate visCometer. The hematoCrit-to-blood visCosity ratio (HVR), i.e. an index of red blood Cell (RBC) oxygen transport effeCtiveness, was CalCulated. RBC deformability was determined at 30 Pa by ektaCytometry, and RBC aggregation properties by sylleCtometry. CC and SC had higher blood visCosity and lower HVR than AA. Nevertheless, HVR was higher in CC Compared to SS and tended to be higher than in SC. The CC group exhibited very rigid hyperChromiC RBC Compared to the three other groups. RBC aggregation abnormalities were observed in CC: low RBC aggregation index and high RBC aggregates strength. Despite these hemorheologiCal abnormalities, CC never had hospitalized painful vaso-oCClusive Crisis or aCute Chest syndrome. In Contrast, all of them had splenomegaly. Of note, 2 out of 7 CC developed retinopathy or otologiC disorders. Whether the blood hypervisCosity and deCreased RBC deformability are responsible for these CompliCations is unknown. The higher oxygen transport effeCtiveness (i.e., HVR) of CC Compared to SS is probably at the origin of the very low risk of mediCal CompliCation in this population.

  • red blood Cell aggregation aggregate strength and oxygen transport potential of blood are abnormal in both homozygous siCkle Cell anemia and siCkle Hemoglobin C Disease
    Haematologica, 2009
    Co-Authors: Julien Tripette, Daniele Mougenel, Eric Beltan, Tawfik Chalabi, Roger Chout, Herbert J. Meiselman, Marie Dominique Hardydessources, Tamas Alexy, Maryse Etiennejulan, Philippe Connes
    Abstract:

    BaCkground ReCent evidenCe suggests that red blood Cell aggregation and the ratio of hematoCrit to blood visCosity (HVR), an index of the oxygen transport potential of blood, might Considerably modulate blood flow dynamiCs in the miCroCirCulation. It thus seems likely that these faCtors Could play a role in siCkle Cell Disease. Design and Methods We Compared red blood Cell aggregation CharaCteristiCs, blood visCosity and HVR at different shear rates between siCkle Cell anemia and siCkle Cell Hemoglobin C Disease (SCC) patients, siCkle Cell trait Carriers (AS) and Control individuals (AA). Results Blood visCosity determined at high shear rate was lower in siCkle Cell anemia (n=21) than in AA (n=52), AS (n=33) or SCC (n=21), and was markedly inCreased in both SCC and AS. Despite differenCes in blood visCosity, both siCkle Cell anemia and SCC had similar low HVR values Compared to both AA and AS. SiCkle Cell anemia (n=21) and SCC (n=19) subjeCts had a lower red blood Cell aggregation index and longer time for red blood Cell aggregates formation than AA (n=16) and AS (n=15), and a 2 to 3 fold greater shear rate required to disperse red blood Cell aggregates. ConClusions The low HVR levels found in siCkle Cell anemia and SCC indiCates a Comparable low oxygen transport potential of blood in both genotypes. Red blood Cell aggregation properties are likely to be involved in the pathophysiology of siCkle Cell Disease: the inCreased shear forCes needed to disperse red blood Cell aggregates may disturb blood flow, espeCially at the miCroCirCulatory level, sinCe red blood Cell are only able to pass through narrow Capillaries as single Cells rather than as aggregates.

Xavier Waltz - One of the best experts on this subject based on the ideXlab platform.

  • rheology of red blood Cells in patients with hbC Disease
    Clinical Hemorheology and Microcirculation, 2016
    Co-Authors: Nathalie Lemonne, Xavier Waltz, Marc Romana, Maryse Etiennejulan, Philippe Connes, Marie Billaud, Regine Hierso
    Abstract:

    : Patients with Hemoglobin C Disease (CC) usually do not develop severe CompliCations in Comparison with individuals with siCkle Cell anemia (SS) or with siCkle Cell Hemoglobin C Disease (SC). The present study Compared the hematologiCal, bioChemiCal, hemorheologiCal and CliniCal CharaCteristiCs of CC patients to those of SS, SC and healthy individuals (AA). Blood visCosity was measured at 225 s(-1) with a Cone plate visCometer. The hematoCrit-to-blood visCosity ratio (HVR), i.e. an index of red blood Cell (RBC) oxygen transport effeCtiveness, was CalCulated. RBC deformability was determined at 30 Pa by ektaCytometry, and RBC aggregation properties by sylleCtometry. CC and SC had higher blood visCosity and lower HVR than AA. Nevertheless, HVR was higher in CC Compared to SS and tended to be higher than in SC. The CC group exhibited very rigid hyperChromiC RBC Compared to the three other groups. RBC aggregation abnormalities were observed in CC: low RBC aggregation index and high RBC aggregates strength. Despite these hemorheologiCal abnormalities, CC never had hospitalized painful vaso-oCClusive Crisis or aCute Chest syndrome. In Contrast, all of them had splenomegaly. Of note, 2 out of 7 CC developed retinopathy or otologiC disorders. Whether the blood hypervisCosity and deCreased RBC deformability are responsible for these CompliCations is unknown. The higher oxygen transport effeCtiveness (i.e., HVR) of CC Compared to SS is probably at the origin of the very low risk of mediCal CompliCation in this population.

  • impaired blood rheology plays a role in the ChroniC disorders assoCiated with siCkle Cell Hemoglobin C Disease
    Haematologica, 2014
    Co-Authors: Nathalie Lemonne, Francois Lionnet, Yann Lamarre, Xavier Waltz, Marc Romana, Marie Dominique Hardydessources
    Abstract:

    Lionnet et al. reCently reported a high prevalenCe of retinopathy (RET) and otologiC disorders (OTD) in patients with siCkle Cell-Hemoglobin C Disease (SC), while a signifiCant number of patients had renal Diseases (mainly glomerulopathy; GLO) and osteoneCrosis (OST). The pathophysiologiCal proCesses of these CompliCations in SC are not well defined, although blood hypervisCosity has been suspeCted, but never tested to the best of our knowledge, as responsible for several ChroniC CompliCations in SC Disease1,2. The aim of this study was to analyze the assoCiations between hematologiCal and hemorheologiCal parameters and ChroniC CompliCations in adult SC patients.

  • relationships between systemiC vasCular resistanCe blood rheology and nitriC oxide in Children with siCkle Cell anemia or siCkle Cell Hemoglobin C Disease
    Clinical Hemorheology and Microcirculation, 2014
    Co-Authors: Yann Lamarre, Marie Petras, Lydia Doumdo, Anne Blanchetdeverly, Jean Martino, Xavier Waltz, Marie Laure Lalannemistrih, Marc Romana, Marie Dominique Hardydessources, Benoit Tressieres
    Abstract:

    VasCular funCtion has been found to be impaired in patients with siCkle Cell Disease (SCD). The present study investigated the determinants of systemiC vasCular resistanCe in two main SCD syndromes in Children: siCkle Cell anemia (SCA) and siCkle Cell-Hemoglobin C Disease (SCC). NitriC oxide metabolites (NOx), hematologiCal, hemorheologiCal, and hemodynamiCal parameters were investigated in 61 Children with SCA and 49 Children with SCC. While mean arterial pressure was not different between SCA and SCC Children, systemiC vasCular resistanCe (SVR) was greater in SCC Children. Although SVR and blood visCosity (ηb) were not Correlated in SCC Children, the inCrease of ηb (+18%) in SCC Children Compared to SCA Children results in a greater mean SVR in this former group. SVR was positively Correlated with ηb, Hemoglobin (Hb) level and RBC deformability, and negatively with NOx level in SCA Children. Multivariate linear regression model showed that both NOx and Hb levels were independently assoCiated with SVR in SCA Children. In SCC Children, only NOx level was assoCiated with SVR. In ConClusion, vasCular funCtion of SCC Children seems to better Cope with higher ηb Compared to SCA Children. SinCe the oCCurrenCe of vaso-oCClusive like CompliCations are less frequent in SCC than in SCA Children, this finding suggests a pathophysiologiCal link between the vasCular funCtion alteration and these CliniCal manifestations. In addition, our results suggested that nitriC oxide metabolism plays a key role in the regulation of SVR, both in SCA and SCC.

  • HematologiC and hemorheologiCal determinants of resting and exerCise-induCed Hemoglobin oxygen desaturation in Children with siCkle Cell Disease.
    Haematologica, 2013
    Co-Authors: Xavier Waltz, Marie-laure Lalanne-mistrih, Marie-dominique Hardy-dessources, Yann Lamarre, Marc Romana, Benoit Tressieres, Roberto F. Machado, Vanessa Tarer, Lydia Divialle-doumdo, Marie Petras
    Abstract:

    The aim of the study was to determine the faCtors assoCiated with resting and exerCise-induCed Hemoglobin oxygen desaturation. The well-established six-minute walk test was ConduCted in 107 siCkle Cell Children (50 with siCkle Hemoglobin C Disease and 57 with siCkle Cell anemia) at steady state. Hemoglobin oxygen saturation was measured before and immediately after the six-minute walk test. Blood samples were obtained on the same day to measure hematologiC and hemorheologiCal parameters. ExerCise-induCed Hemoglobin oxygen desaturation was defined as a drop in Hemoglobin oxygen saturation of 3% or more at the end of the six-minute walk test Compared to resting levels. No Children with siCkle Hemoglobin C Disease, but approximately 50% of Children with siCkle Cell anemia showed mild or moderate oxygen desaturation at rest, whiCh was independently assoCiated with the perCentage of retiCuloCytes. ExerCise-induCed Hemoglobin oxygen desaturation was observed in 18% of Children with siCkle Hemoglobin C Disease and 34% of Children with siCkle Cell anemia, and was independently assoCiated with the six-minute walk test, aCute Chest syndrome rate and the strength of red blood Cell aggregates in Children with siCkle Cell anemia. No assoCiation was found in Children with siCkle Hemoglobin C Disease between exerCise-induCed Hemoglobin oxygen desaturation and the measured parameters. Hemoglobin oxygen desaturation at rest was Common in Children with siCkle Cell anemia but not in Children with siCkle Hemoglobin C Disease, and was mainly assoCiated with greater hemolysis. PhysiologiCal strain during exerCise and red blood Cell aggregation properties may prediCt the oCCurrenCe of exerCise-induCed Hemoglobin oxygen desaturation in Children with siCkle Cell anemia.

  • Severe proliferative retinopathy is assoCiated with blood hypervisCosity in siCkle Cell Hemoglobin-C Disease but not in siCkle Cell anemia.
    Clinical Hemorheology and Microcirculation, 2013
    Co-Authors: Christophe Lemaire, Sadri Chahed, Ioana Botez, Marie-laure Lalanne-mistrih, Nathalie Lemonne, Yann Lamarre, Xavier Waltz, Florence Cabot, Benoit Tressieres, Maryse Etienne-julan
    Abstract:

    Little is known about the impaCt of blood rheology on the oCCurrenCe of retinopathy in siCkle Cell Disease (SCD). Fifty-nine adult SCD patients in steady-state Condition partiCipated to the study: 32 with homozygous SCD (siCkle Cell anemia; SCA) and 27 with siCkle Cell Hemoglobin-C Disease (SCC). The patients underwent retinal examination and were Categorized aCCording to the ClassifiCation of Goldberg: 1) no retinopathy (group 1), 2) non-proliferative or proliferative stage I-II retinopathy (group 2) and 3) proliferative stage III-IV-V retinopathy (group 3). HematologiCal and hemorheologiCal (whole blood visCosity, RBC deformability and aggregation properties) measurements were performed for eaCh patient. In the whole SCD group (SCA + SCC patients) and in SCC patients, the group 3 had higher platelets Count than group 2 but the differenCe between group 3 and group 1 did not reaCh statistiCal signifiCanCe. No differenCe was observed for the other parameters between the three groups. SCC patients from the group 3 exhibited higher whole blood visCosity than SCC patients from the group 1. No signifiCant differenCe was observed between the three groups in SCA patients. This study revealed that severe siCkle proliferative retinopathy is assoCiated with blood hypervisCosity in SCC patients but not in SCA patients.

Maryse Etienne-julan - One of the best experts on this subject based on the ideXlab platform.

  • Severe proliferative retinopathy is assoCiated with blood hypervisCosity in siCkle Cell Hemoglobin-C Disease but not in siCkle Cell anemia.
    Clinical Hemorheology and Microcirculation, 2013
    Co-Authors: Christophe Lemaire, Sadri Chahed, Ioana Botez, Marie-laure Lalanne-mistrih, Nathalie Lemonne, Yann Lamarre, Xavier Waltz, Florence Cabot, Benoit Tressieres, Maryse Etienne-julan
    Abstract:

    Little is known about the impaCt of blood rheology on the oCCurrenCe of retinopathy in siCkle Cell Disease (SCD). Fifty-nine adult SCD patients in steady-state Condition partiCipated to the study: 32 with homozygous SCD (siCkle Cell anemia; SCA) and 27 with siCkle Cell Hemoglobin-C Disease (SCC). The patients underwent retinal examination and were Categorized aCCording to the ClassifiCation of Goldberg: 1) no retinopathy (group 1), 2) non-proliferative or proliferative stage I-II retinopathy (group 2) and 3) proliferative stage III-IV-V retinopathy (group 3). HematologiCal and hemorheologiCal (whole blood visCosity, RBC deformability and aggregation properties) measurements were performed for eaCh patient. In the whole SCD group (SCA + SCC patients) and in SCC patients, the group 3 had higher platelets Count than group 2 but the differenCe between group 3 and group 1 did not reaCh statistiCal signifiCanCe. No differenCe was observed for the other parameters between the three groups. SCC patients from the group 3 exhibited higher whole blood visCosity than SCC patients from the group 1. No signifiCant differenCe was observed between the three groups in SCA patients. This study revealed that severe siCkle proliferative retinopathy is assoCiated with blood hypervisCosity in SCC patients but not in SCA patients.

  • Red blood Cell aggregation, aggregate strength and oxygen transport potential of blood are abnormal in both homozygous siCkle Cell anemia and siCkle-Hemoglobin C Disease
    Haematologica, 2009
    Co-Authors: Julien Tripette, Daniele Mougenel, Eric Beltan, Tawfik Chalabi, Roger Chout, Maryse Etienne-julan, Marie-dominique Hardy-dessources, Olivier Hue, Tamas Alexy, Herbert J. Meiselman
    Abstract:

    BaCkground: ReCent evidenCe suggests that red blood Cell aggregation and the ratio of hematoCrit to blood visCosity (HVR), an index of the oxygen transport potential of blood, might Considerably modulate blood flow dynamiCs in the miCroCirCulation. It thus seems likely that these faCtors Could play a role in siCkle Cell Disease. Design and Methods: We Compared red blood Cell aggregation CharaCteristiCs, blood visCosity and HVR at different shear rates between siCkle Cell anemia and siCkle Cell Hemoglobin C Disease (SCC) patients, siCkle Cell trait Carriers (AS) and Control individuals (AA). Results: Blood visCosity determined at high shear rate was lower in siCkle Cell anemia (n=21) than in AA (n=52), AS (n=33) or SCC (n=21), and was markedly inCreased in both SCC and AS. Despite differenCes in blood visCosity, both siCkle Cell anemia and SCC had similar low HVR values Compared to both AA and AS. SiCkle Cell anemia (n=21) and SCC (n=19) subjeCts had a lower red blood Cell aggregation index and longer time for red blood Cell aggregates formation than AA (n=16) and AS (n=15), and a 2 to 3 fold greater shear rate required to disperse red blood Cell aggregates. ConClusions: The low HVR levels found in siCkle Cell anemia and SCC indiCates a Comparable low oxygen transport potential of blood in both genotypes. Red blood Cell aggregation properties are likely to be involved in the pathophysiology of siCkle Cell Disease: the inCreased shear forCes needed to disperse red blood Cell aggregates may disturb blood flow, espeCially at the miCroCirCulatory level, sinCe red blood Cell are only able to pass through narrow Capillaries as single Cells rather than as aggregates. ©2009 Ferrata Storti Foundation.

Nathalie Lemonne - One of the best experts on this subject based on the ideXlab platform.

  • rheology of red blood Cells in patients with hbC Disease
    Clinical Hemorheology and Microcirculation, 2016
    Co-Authors: Nathalie Lemonne, Xavier Waltz, Marc Romana, Maryse Etiennejulan, Philippe Connes, Marie Billaud, Regine Hierso
    Abstract:

    : Patients with Hemoglobin C Disease (CC) usually do not develop severe CompliCations in Comparison with individuals with siCkle Cell anemia (SS) or with siCkle Cell Hemoglobin C Disease (SC). The present study Compared the hematologiCal, bioChemiCal, hemorheologiCal and CliniCal CharaCteristiCs of CC patients to those of SS, SC and healthy individuals (AA). Blood visCosity was measured at 225 s(-1) with a Cone plate visCometer. The hematoCrit-to-blood visCosity ratio (HVR), i.e. an index of red blood Cell (RBC) oxygen transport effeCtiveness, was CalCulated. RBC deformability was determined at 30 Pa by ektaCytometry, and RBC aggregation properties by sylleCtometry. CC and SC had higher blood visCosity and lower HVR than AA. Nevertheless, HVR was higher in CC Compared to SS and tended to be higher than in SC. The CC group exhibited very rigid hyperChromiC RBC Compared to the three other groups. RBC aggregation abnormalities were observed in CC: low RBC aggregation index and high RBC aggregates strength. Despite these hemorheologiCal abnormalities, CC never had hospitalized painful vaso-oCClusive Crisis or aCute Chest syndrome. In Contrast, all of them had splenomegaly. Of note, 2 out of 7 CC developed retinopathy or otologiC disorders. Whether the blood hypervisCosity and deCreased RBC deformability are responsible for these CompliCations is unknown. The higher oxygen transport effeCtiveness (i.e., HVR) of CC Compared to SS is probably at the origin of the very low risk of mediCal CompliCation in this population.

  • impaired blood rheology plays a role in the ChroniC disorders assoCiated with siCkle Cell Hemoglobin C Disease
    Haematologica, 2014
    Co-Authors: Nathalie Lemonne, Francois Lionnet, Yann Lamarre, Xavier Waltz, Marc Romana, Marie Dominique Hardydessources
    Abstract:

    Lionnet et al. reCently reported a high prevalenCe of retinopathy (RET) and otologiC disorders (OTD) in patients with siCkle Cell-Hemoglobin C Disease (SC), while a signifiCant number of patients had renal Diseases (mainly glomerulopathy; GLO) and osteoneCrosis (OST). The pathophysiologiCal proCesses of these CompliCations in SC are not well defined, although blood hypervisCosity has been suspeCted, but never tested to the best of our knowledge, as responsible for several ChroniC CompliCations in SC Disease1,2. The aim of this study was to analyze the assoCiations between hematologiCal and hemorheologiCal parameters and ChroniC CompliCations in adult SC patients.

  • Severe proliferative retinopathy is assoCiated with blood hypervisCosity in siCkle Cell Hemoglobin-C Disease but not in siCkle Cell anemia.
    Clinical Hemorheology and Microcirculation, 2013
    Co-Authors: Christophe Lemaire, Sadri Chahed, Ioana Botez, Marie-laure Lalanne-mistrih, Nathalie Lemonne, Yann Lamarre, Xavier Waltz, Florence Cabot, Benoit Tressieres, Maryse Etienne-julan
    Abstract:

    Little is known about the impaCt of blood rheology on the oCCurrenCe of retinopathy in siCkle Cell Disease (SCD). Fifty-nine adult SCD patients in steady-state Condition partiCipated to the study: 32 with homozygous SCD (siCkle Cell anemia; SCA) and 27 with siCkle Cell Hemoglobin-C Disease (SCC). The patients underwent retinal examination and were Categorized aCCording to the ClassifiCation of Goldberg: 1) no retinopathy (group 1), 2) non-proliferative or proliferative stage I-II retinopathy (group 2) and 3) proliferative stage III-IV-V retinopathy (group 3). HematologiCal and hemorheologiCal (whole blood visCosity, RBC deformability and aggregation properties) measurements were performed for eaCh patient. In the whole SCD group (SCA + SCC patients) and in SCC patients, the group 3 had higher platelets Count than group 2 but the differenCe between group 3 and group 1 did not reaCh statistiCal signifiCanCe. No differenCe was observed for the other parameters between the three groups. SCC patients from the group 3 exhibited higher whole blood visCosity than SCC patients from the group 1. No signifiCant differenCe was observed between the three groups in SCA patients. This study revealed that severe siCkle proliferative retinopathy is assoCiated with blood hypervisCosity in SCC patients but not in SCA patients.

Herbert J. Meiselman - One of the best experts on this subject based on the ideXlab platform.

  • red blood Cell aggregation aggregate strength and oxygen transport potential of blood are abnormal in both homozygous siCkle Cell anemia and siCkle Hemoglobin C Disease
    Haematologica, 2009
    Co-Authors: Julien Tripette, Daniele Mougenel, Eric Beltan, Tawfik Chalabi, Roger Chout, Herbert J. Meiselman, Marie Dominique Hardydessources, Tamas Alexy, Maryse Etiennejulan, Philippe Connes
    Abstract:

    BaCkground ReCent evidenCe suggests that red blood Cell aggregation and the ratio of hematoCrit to blood visCosity (HVR), an index of the oxygen transport potential of blood, might Considerably modulate blood flow dynamiCs in the miCroCirCulation. It thus seems likely that these faCtors Could play a role in siCkle Cell Disease. Design and Methods We Compared red blood Cell aggregation CharaCteristiCs, blood visCosity and HVR at different shear rates between siCkle Cell anemia and siCkle Cell Hemoglobin C Disease (SCC) patients, siCkle Cell trait Carriers (AS) and Control individuals (AA). Results Blood visCosity determined at high shear rate was lower in siCkle Cell anemia (n=21) than in AA (n=52), AS (n=33) or SCC (n=21), and was markedly inCreased in both SCC and AS. Despite differenCes in blood visCosity, both siCkle Cell anemia and SCC had similar low HVR values Compared to both AA and AS. SiCkle Cell anemia (n=21) and SCC (n=19) subjeCts had a lower red blood Cell aggregation index and longer time for red blood Cell aggregates formation than AA (n=16) and AS (n=15), and a 2 to 3 fold greater shear rate required to disperse red blood Cell aggregates. ConClusions The low HVR levels found in siCkle Cell anemia and SCC indiCates a Comparable low oxygen transport potential of blood in both genotypes. Red blood Cell aggregation properties are likely to be involved in the pathophysiology of siCkle Cell Disease: the inCreased shear forCes needed to disperse red blood Cell aggregates may disturb blood flow, espeCially at the miCroCirCulatory level, sinCe red blood Cell are only able to pass through narrow Capillaries as single Cells rather than as aggregates.

  • Red blood Cell aggregation, aggregate strength and oxygen transport potential of blood are abnormal in both homozygous siCkle Cell anemia and siCkle-Hemoglobin C Disease
    Haematologica, 2009
    Co-Authors: Julien Tripette, Daniele Mougenel, Eric Beltan, Tawfik Chalabi, Roger Chout, Maryse Etienne-julan, Marie-dominique Hardy-dessources, Olivier Hue, Tamas Alexy, Herbert J. Meiselman
    Abstract:

    BaCkground: ReCent evidenCe suggests that red blood Cell aggregation and the ratio of hematoCrit to blood visCosity (HVR), an index of the oxygen transport potential of blood, might Considerably modulate blood flow dynamiCs in the miCroCirCulation. It thus seems likely that these faCtors Could play a role in siCkle Cell Disease. Design and Methods: We Compared red blood Cell aggregation CharaCteristiCs, blood visCosity and HVR at different shear rates between siCkle Cell anemia and siCkle Cell Hemoglobin C Disease (SCC) patients, siCkle Cell trait Carriers (AS) and Control individuals (AA). Results: Blood visCosity determined at high shear rate was lower in siCkle Cell anemia (n=21) than in AA (n=52), AS (n=33) or SCC (n=21), and was markedly inCreased in both SCC and AS. Despite differenCes in blood visCosity, both siCkle Cell anemia and SCC had similar low HVR values Compared to both AA and AS. SiCkle Cell anemia (n=21) and SCC (n=19) subjeCts had a lower red blood Cell aggregation index and longer time for red blood Cell aggregates formation than AA (n=16) and AS (n=15), and a 2 to 3 fold greater shear rate required to disperse red blood Cell aggregates. ConClusions: The low HVR levels found in siCkle Cell anemia and SCC indiCates a Comparable low oxygen transport potential of blood in both genotypes. Red blood Cell aggregation properties are likely to be involved in the pathophysiology of siCkle Cell Disease: the inCreased shear forCes needed to disperse red blood Cell aggregates may disturb blood flow, espeCially at the miCroCirCulatory level, sinCe red blood Cell are only able to pass through narrow Capillaries as single Cells rather than as aggregates. ©2009 Ferrata Storti Foundation.