European Journal of Radiology, 13 ( 199 1) 134-l 31 0 1991 Elsevier Science Publishers B.V. All rights reserved. 0720-048X/91/$03.50

134

EURRAD

00188

Effects of two low osmolality contrast media on red blood cell filterability and aggregation in vitro A. Mary ‘, J. Berlan ‘, C. Bousquet2 and J.P. Senac2 ‘Laboratoire d’hkmatologie,Fact& de Pharmacie. ‘Service de Radiologie,Montpellier,France (Received

14 November

Key words: Contrast

1990; accepted

after revision 4 February

medium, comparative

study; Contrast

1991)

medium, etl’ect

Abstract The in vitro effects ofionic ioxaglate and non-ionic iopamidol were compared. Filtration measurements were carried out on an hemorheometer; erythrocyte aggregation was evaluated by means of an erythrocyte aggregometer, and red blood cell morphology was observed with an optical microscope. Ioxaglate and iopamidol reduced erythrocyte filterability to the same extent; by contrast neither ionic nor non-ionic contrast media significantly modified aggregation or shape of red blood cells. The decrease of erythrocyte deformability observed in this study may cause clotting in catheters or syringes during angiographies investigations.

Introduction Contrast media influence different biological systems in the blood, producing various effects on coagulation, fibrinolysis and platelet function [l-3]. They also induce changes in red blood cell (RBC) morphology, deformability and aggregation [4-61. An inhibitory effect on phagocytic properties of polymorphonuclear leucocytes has also been demonstrated [7]. In clinical practice, thrombophlebitic complications have been reported when hyperosmolar contrast media are used [ 81. By contrast, products of lower osmolality cause less thrombophlebitis [9] and induce, in vitro, only small changes in RBC deformability [5]. In this study, we compared the in vitro effects of two low osmolality contrast media, ionic ioxaglate and nonionic iopamidol on RBC deformability and aggregation. Materials and Methods The contrast media studied were: sodium meglumine ioxaglate (Hexabrix@, 320 mgI/ml) and iopamidol Address for reprints: J.P. Senac, M.D., Service central de radiodiagnostic, Hopital Saint Charles, Montpellier CCdex 34059, France.

300 mgI/ml). Isotonic saline (0.9% (Iopamiron@, NaCl) was used as control. Blood samples from healthy volunteers were heparinized for filtration or anticoagulated with EDTA for aggregation. Preparation of RBC suspensions and filtration technique

RBC suspensions were prepared according to Hanss et al. [lo]. Briefly, heparinized blood was centrifuged at 600 x g, 10 min. Platelet-rich plasma was removed and the buffy coat cells were discarded. A sample of RBC was collected between the top and the bottom of the pellet and was resuspended in an isotonic Tris-HCl buffer (10 mmol/l), pH 7.4, containing NaCl (145 mmol/l), KC1 (4 mmol/l), CaCI, (2 mmol/l), glucose (1 g/l) and serum albumine (0.5 g/l), in order to obtain an 8 y0 hematocrit. Leucocyte contamination was about 100 cells/& a concentration which did not increase filtration resistance [ 111. Filtration measurements were carried out on a hemorheometer as described by Hanss [ 111. The initial flow rate of RBC suspensions was measured through a polycarbonate filter (Nuclepore Corp) with a mean pore of 5 pm. All the filters used were taken from the same batch. Filtration index (FI) was expressed as follows: & - tb FI = ---XX tb

100 H

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H is the hematocrit, tb and t, are the times required to filter a standard volume (60 ~1) of the buffer and RBC suspension, respectively. High FI indicates low RBC filterability. Aggregation technique Erythrocyte aggregation was evaluated by means of an erythrocyte aggregometer MA 1 (Myrenne) according to Schmid-Schonbein et al. [ 121. This device is based on a transparent cone-plate chamber in which blood cells are first subjected for 10 s to high shearing (600 s - ‘) to break up any aggretates. The shearing is then suddenly stopped allowing aggregate formation. The instrument records the light transmission changes through 20 ~1 of whole blood and integrates the area under the curve at the end of a 5 s period. This gives the index of aggregation M. A second measure was carried out on another sample subjected to a high shear rate (600 s - ‘) which was suddenly reduced until 3 s - ‘, instead of 0, during 5 s. This gives a second aggregation index M,. High values of A4 and M, indicate strong RBC aggregation. Before measurements, a sample of whole blood was adjusted at the hematocrit value 40 per cent with autologous plasma, as the erythrocyte aggregation phenomenon is dependent on that parameter [ 131. RBC morphology Morphologic changes in the red cells were studied on blood smears after May-Griinwald-Giemsa staining and optical microscopic examination with a magnification of x 100 (immersion objective). Red cell deformations were assessed, i.e., crenations inducing echinocytes formation. Treatments Before the three measurements RBC suspensions for filtration technique, or whole blood for aggregation and morphology were pre-incubated for 10 min at 37 “C in the presence of contrast media or isotonic saline. Statistical analysis was performed by Student’s t-test. Results RBC filterability Ioxaglate and iopamidol at volume ratios (contrast medium/blood), 2.5 and 5% reduced RBC deformability significantly: High FI values (Fig. 1). At 1% only iopamidol had a significant effect (Table 1). RBC aggregation At all volume ratios (1, 2.5 and 5%), ioxaglate and iopamidol did not significantly modify RBC aggregation

FI

II-

q Q

Isotonic Salme

loxaglate lopamidol

2.5

5.0

46

%

Concentrationv/v

Fig. 1. Filtration Index (FI) measured on RBC suspensions in presence or absence of contrast media (final concentration 2.5% or 5.0% (v/v)). FI, mean f SEM of 10 experiments, each in duplicate. Statistical significance: **P < 0.001 versus isotonic saline.

TABLE 1 Effects of ioxaglate and iopamidol on filtration index (FI). FI

Test solutions:

Mean + SEM Statistical duplicate.

final concetration

1.0% (v/v)

Isotonic saline

Ioxaglate

Iopamidol

8.70 + 0.32

8.91 f 0.22

11.04 + 0.52*

significance:

*P < 0.01 versus isotonic saline. n = 4, in

(Figs. 2 and 3 and Table 2). However, it is evident that only iopamidol decreased aggregation index M and this effect was dose-dependent (Fig. 2). By contrast, both ioxaglate and iopamidol induced slight increase of aggregation index M,: AI values were increased compared with controls (Fig. 3).

TABLE 2 Effects of ioxaglate and iopamidol on aggregation Test solutions: final concetration

index (AI). 1.0% (v/v)

ean f SEM)

M (600 SK’) M, (3 s- ‘)

Isotonic saline

Ioxaglate

Iopamidol

4.98 + 0.80 8.13 + 0.98

4.75 f 1.09 7.83 f 1.00

4.62 & 0.99 8.79 + 0.77

Absence of significant modification compared with isotonic saline, at both high and low shear rates (M, M, ). n = 4, in duplicate.

136 Al

induce more echinocytes formation or aggregates than those observed in isotonic saline (data not shown).

6Isotonic Saline loxaglate lopamidol

H 63

Discussion

6

i

TT

TT

Final

25 %

5.0

%

Concentration

v/v

Fig. 2. Aggregation Index (AI) measured on RBC suspensions in autologous plasma subjected to high shear rate (M = 600 s - ’ ), in presence or absence of contrast media (final concentration 2.5 % or 5.0% v/v). AI = mean + SEM of 10 experiments, each in duplicate. All value differences versus isotonic saline were not significant.

RBC morphology Red cells exposed to both contrast media showed no important deformation compared with controls. Even at 5% volume ratio, ioxaglate and iopamidol did not

w

q

Isotonic Saline loxaglate lopamidol

TT

FInal 62.5

%

46

%

Concentration

v/v

Fig. 3. Aggregation Index (AI) measured on RBC suspensions in autologous plasma subjected to low shear rate (M, = 3 s-i), in presence or absence of contrast media (final concentration 2.5 y0 or 5.0% v/v). AI = mean f SEM of 10 experiments, each in duplicate. All value differences versus isotonic saline were not significant.

In the present study, it has been demonstrated that two low osmolality contrast media significantly reduced RBC filterability. The decrease of erythrocyte deformability observed is in agreement with previously reported results [ 51. At 5 y0 volume ratio, no difference existed between the two contrast media, ionic and non-ionic. We also observed in 1,2.5 and 5% volume ratios, that ioxaglate and iopamidol produced no important morphologic changes. By contrast, le Mignon et al. [ 141 found that ioxaglate produced a slight increase of erythrocyte deformability while iopamidol reduced RBC filterability and induced more echinocytes formation than ioxaglate. It is known that contrast media with low osmolalities, as the ones we have used, induce small changes in shape [ 151. Moreover, Aspelin et al. [4] have found that ionic metrizoate and non-ionic iohexol produced few changes in RBC morphology even in a volume ratio of 20% ; iohexol inducing the smallest changes. By an aggregometric method, we demonstrated a decrease in the aggregation index M in a dose-dependant way with iopamidol. This result is in accordance with previous findings obtained with iohexol [6,16]. We also found a slight increase in aggregation index M 1 with both contrast media, which is in agreement with microscopic examination of irregular red cell aggregates caused by ioxaglate [ 171. The partial differences between the present and the earlier results may be due to the different methods used and also to the various volume ratios of contrast medium to blood. Furthermore, anticoagulative drugs may enhance or inhibit the effects of contrast media [ 171. The conclusions should be taken cautiously. The in vitro tests do not reflect what may occur in vivo circulation, but is comparable to what occurs in catheters or syringes used during angiographic investigations. Blood-clot formation has been observed in angiographic syringes, in particular with non-ionic contrast media [ 181. However, neither ionic nor non-ionic products have presented a thrombogenic activity in vitro. RBC deformability and aggregation are two important factors influencing the blood viscosity [ 191. The decrease of erythrocyte deformability induced by contrast media may disturb the blood flow and partly contribute to the clotting of syringes or catheters. Lowosmotic contrast media produce minor changes and should therefore be used with a maximum security for angiographic techniques.

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References 1 Stormorken H, Skalpe I,Testart MC. Effects ofvarious contrast media on coagulation, Iibrinolysis and platelet function: an in vitro and in vivo study. Invest Radio1 1986; 21: 348-354. 2 Koneti Rao A, Rao VM, Willis J, Beckett Ch, Steiner RM. Inhibition of platelet function by contrast media: iopamidol and ioxaglate versus iothalamate. Radiology 1985; 156: 31 l-313. 3 Jeffrey J, Douglas C, Bull BS. Differing mechanisms of clotting inhibition by ionic and non-ionic contrast agents. Radiology 1989; 172: 345-348. 4 Aspelin P, Stohr-Liessen M, Almen T. Effect of iohexol on human erythrocytes. I. Changes of red cell morphology in vitro. Acta Radio1 1980; Suppl 362: 117-122. 5 Aspelin P, Teitel P, Almen T. Effect of iohexol on red cell deformability in vitro. Acta Radio1 1980; Suppl 362: 127-130. 6 Aspelin P, Birk A, Almen T, Kiesewetter H. Effect of iohexol on human erythrocytes. II. Red cell aggregation in vitro. Acta Radio1 1980; Suppl 362; 123-126. 7 Rasmussen F, Georgsen J, Grunnet N. Influence of radiographic contrast media on phagocytosis. Acta Radio1 1988; 29: 598-592. 8 Zinner G, Gottlob R. Morphologic changes in vessel endothelia caused by contrast media. Angiology 1959; 10: 207-213. 9 Thomas ML, Briggs GM, Kuan BB. Contrast agent-induced thrombophlebitis following leg phlebography: meglumine ioxaglate versus meglumine iothalamate. Radiology 1983; 147: 399-400. 10 Hanss M, Gattegno L, Delatour E, Gaudey F, Koutsouris D. Proctdt rapide de preparation d’hematies destinees a des

mesures de deformabilite. Nouv Rev Fr Hematol 1985; 27: 327-331. 11 Hanss M. Erythrocyte liltrability measurement by the initial flow rate method. Biorheology 1983; 20: 199-211. 12 Schmid-Schoenbein H, Volger E, Teitel P, Kiesewetter P, Dauer U, Heilmann L. New haemorheological techniques for the routine laboratory. Clin Haemorheol 1982; 2: 93-105. 13 Agosti R, Clivati A, D’Ettorre M, Ferrarini F, Somazzi R, Longhini E. Hematocrit dependence of erythrocyte aggregation. Clin Haemorheol 1988; 8: 913-924. 14 Le Mignon MM, Nain Dit Ducret M, Bonnemain B, Donadieu AM. Effect of contrast media on whole blood tiltrability: an in vitro comparative study of iohexol, iopamidol and ioxaglate on rat blood. Acta Radio1 1988; 29: 593-597. 15 Aspelin P. Effect of ionic and non ionic contrast media on morphology of human erythrocytes. Acta Radio1 Diagn 1978; 19: 675. 16 Aspelin P, Schmid-Schoenbein H. Effect of ionic and non-ionic contrast media on red cell aggregation in vitro. Acta Radio1 Diagn 1978; 19: 766. 17 Raininko R, Ylinen SL. Effect of ionic and non-ionic contrast media on aggregation of red blood cells in vitro. A preliminary report. Acta Radiol. 1987; 28: 87-92. 18 Robertson H. Blood clot formation in angiographic syringes containing non-ionic contrast media. Radiology 1987; 163: 621-622. 19 Aspelin P. Effect of ionic and non-ionic contrast media on whole blood viscosity, plasma viscosity and hematocrit in vivo. Acta Radio1 Diagn 1978; 19: 977.

Effects of two low osmolality contrast media on red blood cell filterability and aggregation in vitro.

The in vitro effects of ionic ioxaglate and non-ionic iopamidol were compared. Filtration measurements were carried out on an hemorheometer; erythrocy...
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