C i ical Ca e Explo a ions www.ccejou nal.o g 1
DOI: 10.1097/CCE.0000000000000763
Copy igh © 2022 The Au ho s.
Published by Wol e s Kluwe
Heal h, Inc. on behal o he
Socie y o C i ical Ca e Medicine.
This is an open-access a icle dis-
ibu ed unde he e ms o he
C ea i e Commons A ibu ion-Non
Comme cial-No De i a i es License
4.0 (CCBY-NC-ND), whe e i is pe -
missible o download and sha e he
wo k p o ided i is p ope ly ci ed.
The wo k canno be changed in any
way o used comme cially wi hou
pe mission om he jou nal.
OBJECTIVES: Ca diac su ge y is equen ly associa ed wi h signi ican pos op-
e a i e bleeding. Pla ele -dys unc ion is he main ca diopulmona y bypass (CPB)-
induced hemos a ic de ec . No only he numbe o pla ele s dec eases, bu also
he emaining a e unc ionally impai ed. Al hough lipid me abolism is c ucial o
pla ele unc ion, li le is known ega ding pla ele me abolic changes associa ed
wi h CPB-dys unc ion. Ou aim is o explo e possible con ibu ion o me abolic
pe u ba ions o pla ele dys unc ion a e ca diac su ge y.
DESIGN: P ospec i e coho s udy.
SETTING: Te ia y academic ca dio ho acic-su ge y ICU.
PATIENTS: Thi y- h ee pa ien s submi ed o elec i e su gical ao ic al e
eplacemen .
INTERVENTIONS: Samples om pa ien s we e collec ed a h ee ime poin s
(p eope a i e, 6- and 24-h pos ope a i e). Un a ge ed me abolic analysis using
high-pe o mance liquid ch oma og aphy- andem mass spec ome y was pe -
o med o compa e pa ien s wi h signi ican pos ope a i e bleeding wi h pa ien s
wi hou hemo hage. P incipal componen analyses, Wilcoxon ma ched-pai s
signed- ank es s, adjus ed o FDR, and pai wise compa ison we e used o iden-
i y pa hways o in e es . En ichmen and pa hway me abolomic complemen ed
he analyses.
MEASUREMENTS AND MAIN RESULTS: We iden i ied a pla ele - ela ed sig-
na u e based on an o e ep esen a ion o changes in known a y acid me abolism
pa hways in ol ed in pla ele unc ion. We obse ed ha a achidonic acid (AA)
le els and o he me aboli es om he pa hway we e educed a 6 and 24 hou s,
independen ly om an iag egga ion he apy and pla ele coun . Concen a ions
o p eope a i e AA we e in e sely co ela ed wi h pos ope a i e ches ube blood
loss bu we e no co ela ed wi h pla ele coun in he p eope a i e, a 6 o a 24
hou s. Pa ien s wi h signi ican pos ope a i e blood-loss had conside ably lowe
alues o AA and highe ans usion a es. Values o pos ope a i e in e leukin-6
we e s ongly co ela ed wi h AA a iabili y.
CONCLUSIONS AND RELEVANCE: Ou obse a ions sugges ha an in lam-
ma o y- ela ed pe u ba ion o AA me abolism is a signa u e o ca diac su ge y
wi h CPB and ha p eope a i e le els o AA may be mo e ele an han pla ele
coun o an icipa e and p e en pos ope a i e blood loss in pa ien s submi ed o
ca diac su ge y wi h CPB.
KEY WORDS: ca diac su ge y; in lamma ion; me abolism; pla ele ; pos ope a i e
bleeding
Excessi e bleeding is a equen complica ion a e ca diac su ge y wi h ca di-
opulmona y bypass (CPB), equen ly equi ing he use o allogenic blood
p oduc s. Ca diac su ge y accoun s o 10–15% o ans usions in su gical
pa ien s in he Uni ed S a es yea ly (1, 2), and mo e han hal o pa ien s ecei e
ans usion o blood p oduc s du ing hospi al s ay (3). Use o ans usions is no
Tiago R. Velho, MD1,2
Rica do Fe ei a, MD2,3
Ka ha ina Willmann, PhD1
Do a Ped oso, PhD1
Tiago Paixão, PhD1
Ra ael Maniés Pe ei a, CLP2
Nádia Junquei a, MD2
Nuno Ca alho Gue a, MD2
Dulce B i o, PhD3,4
Ana G. Almeida, PhD3,4
Ângelo Nob e, MD2,3
Thomas Köche , PhD5
Faus o Pin o, PhD3,4
Luís Fe ei a Moi a, PhD1
Role o Omega-6 Fa y Acid Me abolism in
Ca diac Su ge y Pos ope a i e Bleeding Risk
OBSERVATIONAL STUDY
Velho e al
2 www.ccejou nal.o g Oc obe 2022 • Volume 4 • Numbe 10
ha mless, signi ican ly impac ing pa ien s’ ou come and
inc easing bo h mo bidi y and mo ali y, and heal hca e
cos s (4). Fu he mo e, pos ope a i e bleeding is also as-
socia ed wi h a highe a e o eope a ion, which is inde-
penden ly associa ed wi h poo e ou comes (5).
CPB has a dis inc i e and signi ican con ibu ion
o he dis up ion o hemos asis in ca diac su ge y
(6, 7). Pla ele - unc ion de ici is conside ed as he
main CPB-induced hemos a ic de iciency (8). CPB
dec eases he numbe o pla ele s by dilu ion, ad-
hesion, des uc ion, and consump ion (9), and his
educ ion is associa ed wi h excessi e pos ope a i e
bleeding (9). Fu he mo e, emaining pla ele s a e
unc ionally impai ed, bu mechanisms emain un-
clea (10). E en pa ien s wi h a no mal pla ele coun
show highe p e alence o pla ele dys unc ion o
unknown-cause (11). Al hough ci cula ing pla ele s
appea s uc u ally no mal, eco e ing wi hin min-
u es a e CPB, bleeding imes inc ease and emain
p olonged o se e al hou s (12). Flow cy ome y
in whole-blood a e CPB e ealed no signi ican
changes in pla ele su ace ecep o s (8), and ew
ad ances ha e been made in he ield ecen ly.
While lipid me abolism is essen ial o pla ele ac-
i i y and unc ion (13), li le is known ega ding pla ele
me abolic changes associa ed wi h CPB-dys unc ion. To
explo e he possible con ibu ion o me abolic pe u ba-
ions o pla ele dys unc ion a e ca diac su ge y wi h
CPB, we pe o med an un a ge ed me abolomic analysis
using high-pe o mance liquid ch oma og aphy- andem
mass spec ome y o iden i y speci ic me abolic signa-
u es ha con ibu e o pla ele dys unc ion a e CPB.
MATERIALS AND METHODS
S udy Popula ion
The ao ic al e eplacemen o in lamma ion
(SVA-S udy) egis y is a s udy o cha ac e ize he
in lamma o y esponse a e su gical ao ic al e
eplacemen (SAVR). Pa ien s included we e olde
han 18 yea s unde going SAVR. P e ious ca diac
su ge y, concomi an p ocedu es, neoplasia, and
use o co icos e oids we e exclusion c i e ia. Blood
was collec ed om 33 pa ien s be o e su ge y, and
6 and 24 hou s a e su ge y. Plasma was p epa ed
and s o ed a –80°C. Medical eco ds we e assessed
o ob ain clinical da a. All pa ien s p o ided w i en
in o med consen , and he s udy was app o ed by
he Ins i u ional E hics Commi ee (Comissão É ica-
Cen o Hospi ala Lisboa No e, Re . N.º23/18, Ap il
2018), in acco dance wi h Decla a ion o Helsinki
and ollowing STROBE guidelines.
Classi ica ion o Hemo hage
Pos ope a i e ches ube ou pu was quan i ied in he
ICU hou ly. Signi ican bleeding was conside ed when
pos ope a i e ches ube blood loss was abo e 600 mL
wi hin 12 hou s, as de ined by he In e na ional
Ini ia i e on Haemos asis Managemen in Ca diac
Su ge y (14). The need o ans usion (pla ele con-
cen a e, packed ed-blood cells, esh ozen plasma,
and ib inogen) was conside ed acco ding o bleeding
and/o o co ec agg ega ion and coagula ion de i-
ciencies (6, 15).
Un a ge ed Me abolomics
A e gene a ion o blood plasma, p o eins we e
emo ed by adding 400 uL o a me hanol/e hanol mix-
u e (4:1, / ) o 100 ul o plasma, ollowed by igo ous
o ex shaking o 5 minu es a oom- empe a u e and
cen i uga ing a 4000 × g o 10 minu es a 4°C. The su-
pe na an was collec ed, ans e ed o an Eppendo ,
shock ozen wi h liquid ni ogen, and s o ed a –80°C
un il analysis. Ex ac ed samples we e hawed on ice,
cen i uged o 2 minu es a 15,000 × g, and dilu ed
acco ding o he di e en sample weigh wi h 0.1%
o mic acid ( e e sed phase [RP]) o 50% ace oni ile
KEY POINTS
• Ques ion: Wha is he ole o pla ele -me a-
bolic pe u ba ion in ca diac su ge y pos ope -
a i e bleeding?
• Findings: In ou s udy we ha e analyzed he
me abolic pe u ba ions o 33 pa ien s submi -
ed o ao ic al e eplacemen , iden i ying a
pla ele - ela ed signa u e based on an o e ep-
esen a ion o changes in a y acid me abolism
pa hways.
• Meaning: In pa ien s submi ed o ca diac su -
ge y, he in lamma o y pe u ba ion o pla ele
a y acid me abolism has a signi ican ole in
pos ope a i e bleeding.
Obse a ional S udy
C i ical Ca e Explo a ions www.ccejou nal.o g 3
(ACN) (hyd ophilic in e ac ion ch oma og aphy
[HILIC]). A o al o 2.5 mL o each dilu ed sample
was pooled and used as a quali y con ol (QC) sample.
Samples we e andomly assigned in o he au osample ,
and me aboli es we e sepa a ed on a SeQuan ZIC-
pHILIC HPLC column (Me ck, 100 3 2.1 mm; 5 mm)
o an RP-column (Wa e s, ACQUITY ® ul a - pe -
o mance liquid ch oma og aphy high s eng h silica
T3 150 3 2.1;1.8 mm) wi h a low a e o 100 mL/min
deli e ed h ough an Ul ima e 3000 HPLC sys em
(The mo-Fishe Scien i ic). The g adien amp-up
ime akes 25 minu es om 10% o 80% B in HILIC (A:
ACN; B: 25 mM ammonium bica bona e in wa e ) and
om 1% o 90% B in RP (A: 0.1% o mic acid in wa e ;
B: 0.1% o mic acid in ACN). Me aboli es we e ionized
ia elec osp ay ioniza ion in pola i y swi ching mode
a e HILIC sepa a ion and in posi i e pola i y mode
a e RP sepa a ion. Sample spec a we e acqui ed by
da a-dependen high- esolu ion andem mass spec-
ome y on a Q-Exac i e Focus (The mo-Fishe
Scien i ic). Ioniza ion po en ial was se o +3.5/–3.0 kV,
he shee gas low was se o 20, and an auxilia y gas low
o 5 was used. Samples we e analyzed in a andomized
ashion, and QC samples we e addi ionally measu ed
in con i ma ion mode o ob ain addi ional MS/MS
spec a o iden i ica ion. Ob ained da ase s we e p o-
cessed by compound disco e e 3.0 (The mo-Fishe
Scien i ic). Compound anno a ion was conduc ed by
sea ching he mzCloud da abase wi h a mass accu acy
o 3 ppm o p ecu so masses and 10 ppm o ag-
men ion masses as well as ChemSpide wi h a mass
accu acy o 3 ppm using BioCyc, Human Me abolome
Da abase, Kyo o Encyclopedia o Genes and Genome,
MassBank, and Me aboLigh s as da abases.
Cy okine Measu emen
Cy okine concen a ions we e de e mined using he
human in e leukin-6 (IL-6) ki (ELISA-MAX Deluxe
Se s, BioLegend, San Diego, CA), acco ding o manu-
ac u e ’s p o ocol and measu ed on a Tecan spec o-
pho ome e pla e- eade .
S a is ical Analysis
P incipal componen analysis (PCA) was pe o med
wi h R (16), using he basic package “s a s.” Remaining
s a is ical analysis was pe o med using G aphPad P im
9.0 (G aphPad So wa e, San Diego, CA). Con inuous
a iables a e p esen ed wi h median wi h in e qua -
ile ange (IQR) and we e analyzed using Wilcoxon
ma ched-pai signed ank es o pai ed samples
and Wilcoxon ank-sum es o nonpai ed samples,
adjus ed o alse disco e y a e. Pai wise compa -
ison was pe o med be ween p e- and pos ope a i e
samples. The Bon e oni co ec ion was pe o med o
educe he chances o ob aining alse-posi i e esul s
( ype I e o s). Ca ego ical a iables a e epo ed in
pe cen age o equency and we e analyzed using chi-
squa e es . Fo co ela ion, we used he Spea man
ank-o de co ela ion. P edic i e models we e pe -
o med using logis ic eg ession. En ichmen and
pa hway me abolomic analysis was pe o med using
he Me aboAnalys 5.0 ool (17). The ollowing sym-
bols we e used in igu es o indica e s a is ical signi i-
cance: ns: nonsigni ican ; p < 0.05(*); p < 0.01(**); p <
0.001(***); p < 0.0001(****).
RESULTS
Un a ge ed Me abolomics
Pa ien s demog aphic and clinical cha ac e is ics a e
de ailed in Table1. No di e ences we e obse ed be-
ween he wo g oups (signi ican bleeding and no
signi ican bleeding) ega ding age, gende , como bidi-
ies, le en icle unc ion, and median Eu osco e II.
Un a ge ed me abolomics da a o he comple e pop-
ula ion eco ded 8,668 me abolic ea u es o each
plasma sample. To iden i y me aboli es associa ed wi h
an inc eased isk o pos ope a i e hemo hage, we em-
ployed mul i a ia e analysis, mainly pa e n ecogni ion
ools, such as PCA, be ween pa ien s wi h o wi hou
signi ican pos ope a i e hemo hage. The PCA plo
did no e eal a clea sepa a ion in he me abolic p o-
ile be ween bo h g oups. We ha e hen pe o med a
pai wise hypo hesis es compa ing p e- and pos ope -
a i e me aboli e measu emen s a 24 hou s. The pai -
wise hypo hesis es iden i ied s a is ically signi ican
di e ences o 547 me aboli es (p alue < 0.001). Using
he 547 signi ican me aboli es, an en ichmen and
pa hway analysis was pe o med. F om he op 30 pa h-
ways iden i ied in ou analysis (Supplemen a y Fig.1,
A and B, h p://links.lww.com/CCX/B57), we iden i-
ied a pla ele - ela ed signa u e, cha ac e ized by an
o e ep esen a ion o changes in one known a y acid
me abolism pa hway (a achidonic acid [AA] pa hway)
in ol ed in pla ele unc ion. Al hough i was no he
Velho e al
4 www.ccejou nal.o g Oc obe 2022 • Volume 4 • Numbe 10
TABLE 1.
Su ge y and Pos ope a i e Da a
Va iable All Pa ien s
No Signi ican
Bleeding
Signi ican
Bleeding p
n33 22 11
Age, y , median (IQR) 73.5 (68.5–76.8) 75 (69.3–80.3) 71.5 (67.3–74) 0.115
Male sex, n (%) 16 (48.5) 11 (50) 5 (45.5) > 0.999
Body mass index (kg/m2) 27.8 (24.7–30.5) 27.5 (24.7–29.8) 28.4 (23.3–31.8) 0.849
Use o an iagg ega ion, n (%)
Ace ylsalicylic acid 15 (45.5) 10 (45.5) 5 (45.5) > 0.999
Hype ension, n (%) 24 (72.7) 14 (63.6) 10 (90.9) 0.212
Diabe es melli us, n (%) 11 (33.3) 5 (22.7) 6 (54.5) 0.117
Dyslipidemia, n (%) 7 (21.2) 4 (18.2) 3(27.3) 0.661
Ch onic kidney disease, n (%) 4 (12.1) 3 (13.6) 1 (9.1) > 0.999
Pe iphe al ascula disease, n (%) 3 (9.1) 2 (9.1) 1 (9.1) > 0.999
Ce eb o ascula disease, n (%) 0 (0) 0 (0) 0 (0) –
Ch onic lung disease, n (%) 5 (15.2) 4 (18.2) 1 (9.1) 0.643
Ischemic ca diopa hy, n (%) 6 (18.2) 4 (18.2) 2 (18.2) > 0.999
P e ious ca diac su ge y, n (%) 0 (0) 0 (0) 0 (0) –
P ese ed LV unc ion, n (%) 33 (100) 22 (100) 11(100) > 0.999
Mode a e LV unc ion 31–50%, n (%) 0 (0) 0 (0) 0 (0) –
Poo LV unc ion (21–30%), n (%) 0 (0) 0 (0) 0 (0) –
Ve y poo LV unc ion (<20%), n (%) 0 (0) 0 (0) 0 (0) –
Eu oSCORE II (IQR) 1.3 (1–1.83) 1.37 (1.01–2.1) 1.1 (0.94–1.85) 0.536
Ca diopulmona y bypass ime, min (IQR) 36.5 (32.3–64) 36.5 (31.8–66) 38 (32.3–59.5) > 0.999
C oss-clamp ime, min (IQR) 27.5 (22.3–52.5) 26.5 (22.8–53.5) 31 (21–50) 0.865
SOFA 24 h , median (IQR) 1 (0–4) 1 (0–3.5) 2 (1–4) 0.218
SOFA 0 a 24 h (%) 11 (33) 10 (45.5) 1 (9.1) 0.037
Pos ope a i e bleeding (mL) 400 (300–600) 300 (300–400) 600 (600–700) < 0.0001
Necessi y o ans usion 11 (33.3) 6 (27.3) 5 (45.5) 0.437
RBCs 8 (24.2) 4 (18.2) 2 (18.2) > 0.999
Pla ele concen a e 6 (18.2) 3 (13.6) 5 (45.5) 0.083
F esh ozen plasma 5 (15.2) 2 (9.1) 1 (9.1) > 0.999
Reope a ion due o amponade, n (%) 0 (0) 0 (0) 0 (0) –
Acu e kidney inju y n (%) 14 (42.4) 9 (40.5) 5 (45.5) 0.803
A ial ib illa ion, n (%) 8 (24.2) 8 (36.4) 0 (0) 0.022
Haemodynamic suppo , n (%) 13 (39.4) 7 (31.8) 6 (54.5) 0.208
Mechanical en ila ion >6 h , n (%) 12 (36.4) 5 (22.7) 7 (63.6) 0.021
Neu ologic complica ions, n (%) 3 (9.1) 0 (0) 3 (27.3) 0.01
In ec ion, n (%) 1 (3) 1 (4.5) 0 (0) 0.472
Wound in ec ion, n (%) 0 (0) 0 (0) 0 (0) –
ICU leng h o s ay 2 (1–3) 2 (1–3) 2 (2–4) 0.352
Hospi al leng h o s ay 6 (5–7) 6 (5–7) 6 (5–7) 0.806
Discha ge, n (%)
O he hospi al 4 (12.1) 2 (9.1) 2 (18.2) 0.451
Home 29 (87.9) 20 (90.9) 9 (81.8)
Eu oSCOREII = Eu opean Sys em o Ca diac Ope a i e Risk E alua ion II, IQR = in e qua ile ange, LV = le en icula , SOFA =
Sequen ial O gan Failu e Assessmen .
Hemodynamic suppo : use o asop esso s o main ain adequa e pe usion, wi hou he need o mechanical suppo .
Neu ologic complica ion: occu ence o s oke, deli ium, o pos ope a i e cogni i e dys unc ion.
Obse a ional S udy
C i ical Ca e Explo a ions www.ccejou nal.o g 5
mos signi ican pa hway iden i ied in ou me aboli es’
se , i was an excellen candida e o a pa hway wi h im-
pac on pla ele dys unc ion, since AA is an essen ial
con ibu o o pla ele ’s unc ion. As ou aim was o
e alua e he con ibu ion o me abolic pe u ba ions o
pla ele dys unc ion, we p oceeded o assess changes in
he AA me abolism. The lis o he s udied me aboli es,
associa ed wi h he iden i ied pa hway, is p esen ed in
Supplemen a y Table 1 (h p://links.lww.com/CCX/
B57). Fu he iden i ica ion o he o he signi ican
me aboli es and/ o pa hways was no comple ed.
We ha e e alua ed he concen a ions o he nine
ea u es associa ed wi h he AA pa hway: AA, eicosa-
pen aenoic acid (EPA), docosahexaenoic acid (DHA),
conjuga ed linoleic acids (CLAs), pla ele -ac i a ing ac o
(PAF) (as pa o he ups eam ac i a ion o AA me abo-
lism), 8,11,14-eicosa ienoic acid (eicosanoids pa hway),
12-Hyd oxyeicosa e aenoic acid (12-HETE) and glu-
amic acid (lipoxygenase pa hway), and h omboxane B2
(TxB2) (cyclooxygenase pa hway) (Supplemen a y Fig. 1,
C and D, h p://links.lww.com/CCX/B57).
Conside ing all pa ien s wi h measu emen s o he
h ee ime-poin s, le els o AA in he p eope a i e we e
5.93 × 108 (ion coun s—all he alues a e ion coun s
[a ea] linea ly p opo ional o he ac ual concen a-
ion o he me aboli e) (IQR, 4.4 × 108 o 7.4 × 108).
Al hough absolu e measu emen s emained s able a 6
hou s—5.6 × 108 (IQR, 4.3 × 108 o 7.1 × 108; p = 0.55),
hey we e signi ican ly dec eased a 24 hou s 4.17 × 108
(IQR, 3.08 × 108 o 5.5 × 108; p < 0.0001; Supplemen a y
Fig. 2A, h p://links.lww.com/CCX/B57).
Re ealing a simila pa e n, le els o EPA (7.98 × 107;
IQR, 5.15–12.67 × 107) and DHA (5.23 × 108; IQR, 4.5–
8.06 × 108) emained s able a 6 hou s (8.19 × 107; IQR,
4.92–10.8 × 107; p = 0.247 and 5.43 × 108; IQR, 3.57–
7.34 × 108; p = 0.505, espec i ely) bu signi ican ly
dec eased a 24 hou s (4.27 × 107; IQR, 2.95–6.86 × 107;
p < 0.0001 and 3.57 × 108; IQR, 2.54–5.41 × 108, p <
0.0001, espec i ely; Supplemen a y Fig. 2A, h p://
links.lww.com/CCX/B57). CLA inc eased a 6 hou s
(3.1 × 108; IQR, 1.8–4.91 × 108; p = 0.059) and e u ned
o nea basal concen a ions a 24 hou s (2.3 x 108;
IQR, 1.36–3.9 × 108; p = 0.972; Supplemen a y Fig. 2A,
h p://links.lww.com/CCX/B57).
AA me aboli es de i ed om he lipoxygenase
pa hway, such as glu amic acid (20.59 × 108; IQR, 15.97–
25.02) and 12-HETE (1.45 × 107; IQR, 0.92–1.98), had
a signi ican educ ion in he absolu e measu emen s a
6 hou s (13.37 × 108; IQR, 9.97–17.03 × 108; p < 0.0001
and 1.17 x 107; IQR, 0.77–1.54 × 107; p < 0.0001, espec-
i ely) and 24 hou s (13.03 × 108; IQR, 8.58–16.56 × 108;
p < 0.001, and 1.13 × 107; IQR, 0.88–1.63 × 107; p <
0.0001, espec i ely; Supplemen a y Fig. 2A, h p://
links.lww.com/CCX/B57).
PAF concen a ions (16.99 × 108; IQR, 14.05–
18.8 × 108) we e signi ican ly educed a 6 hou s
(9.65 × 108; IQR, 7.56–11.37 × 108; p < 0.0001) and 24
hou s (6.89 × 108; IQR, 5.86–8.16 × 108; p < 0.0001),
compa ible wi h he p e iously epo ed educ ion o
pla ele ac i i y a e CPB. No signi ican changes we e
obse ed in TxB2 concen a ions a 6 and 24 hou s.
In e es ingly, he concen a ions o 8,11,14-eicosa-
ienoic acid (1.83 × 108; IQR, 1.37–2.32 x 108) we e
unchanged a 6 hou s (2.06 × 108; IQR, 1.51–2.38 × 108;
p = 0.271) bu educed a 24 hou s (1.24 × 108; IQR,
1–1.53 × 108; p < 0.001).
Because wo pos ope a i e measu emen s we e
es ed o he nine me aboli es, a Bon e oni-adjus ed
signi icance le el o 0.00278 was calcula ed o accoun
o he inc eased possibili y o ype-I e o .
To e alua e i he a ia ion o he me aboli es ol-
lowed a simila end han he absolu e alue, we hen
calcula ed he change in he me aboli es measu emen s
a 6 and 24 hou s (pe cen age o change compa ing o
p eope a o y le els; Supplemen a y Fig. 2B, h p://
links.lww.com/CCX/B57; and Supplemen a y Table
2, h p://links.lww.com/CCX/B57). Al hough a high
pe cen age o pa ien s had a p onounced educ ion a
6 hou s, median educ ion o AA, EPA, and DHA was
no signi ican a 6 hou s. Howe e , le els we e signi -
ican ly educed a 24 hou s. On he o he hand, CLA
had an inc ease a 6 hou s wi h a nonsigni ican a i-
a ion a 24 hou s. Glu amic acid and 12-HETE had a
simila pa e n o educ ion bo h a 6 and 24 hou s.
Al hough PAF measu emen was educed a 6 hou s,
he educ ion was e en mo e p onounced a 24 hou s.
In con as , TxB2 alues we e mo e educed a 6 hou s
han a 24 hou s; 8,11,14-eicosa ienoic acid showed
a pa icula pa e n, wi h a median inc ease o 19.4%
(–15% o 44.8%), signi ican ly dec easing a 24 hou s.
Pla ele Coun and Mo phology and An ipla ele
The apy
In ou popula ion, pla ele coun dec eased a e su -
ge y (Fig. 1A), wi h a median –32.8% (–39.5% o
Velho e al
6 www.ccejou nal.o g Oc obe 2022 • Volume 4 • Numbe 10
Figu e 1. Pla ele coun (A), a iabili y in pe cen age (B), pla ele mean olume (C), and pla ele dis ibu ion wid h (D) o p eope a i e
and 6- and 24-h pos ope a i e pa ien s. Values a e p esen ed in median wi h in e qua ile ange.
–28.8%) a 6 hou s and –28.5% (–35% o –18.2%) a 24
hou s (Fig. 1B). The educ ion was consis en wi hin
all pa ien s (Fig. 1B) and was no co ela ed wi h any
como bidi y o he use o an icoagula ion and/o an i-
agg ega ion (da a no shown). Consis en wi h p e-
ious epo s, mean pla ele olume (MPV) was also
educed a 6 and 24 hou s (Fig. 1C). Howe e , pla ele
dis ibu ion wid h (PDW) emained s able a all imes
(Fig. 1D).
Impo an ly, he a ia ion in he pos ope a i e
me aboli e le els was no induced by he CPB educ-
ion o pla ele coun , since pla ele coun a p eope -
a i e, 6 hou s, and 24 hou s was no co ela ed wi h
me aboli es measu emen nei he wi h he pe cen age
o a ia ion in he same ime poin (da a no shown).
The absolu e alue and he a ia ion o he me aboli es
we e also no co ela ed wi h he a ia ion in he MPV
and PDW (da a no shown).
Conside ing ha a subs an ial pe cen age o pa ien s
we e medica ed wi h pla ele inhibi o s (AAT), we
assessed i p eope a i e AAT in luenced p eope -
a i e le els and hei a ia ion. None o ou pa ien s
was aking nons e oidal an i-in lamma o y d ugs,
and 45.5% (15 pa ien s) we e aking ace ylsalicylic
acid (ASA) (Table1). Pa ien s aking ASA had simila
le els o he s udied me aboli es in he p eope a i e
Figu e 2. A, Co ela ion o pos ope a i e bleeding (mL) wi hin he i s pos ope a i e 12 h and p eope a i e quan i ica ion o a achidonic
acid. B, P eope a i e a achidonic acid le els be ween pa ien s wi h (g een) o wi hou ( ed) a signi ican pos ope a i e bleeding (de ined
by pos ope a i e ches ube blood loss o mo e han 600 mL wi hin 12 h ). C, Median pos ope a i e ches ube blood wi hin 12 h
acco ding o a achidonic acid quan i ica ion.
Obse a ional S udy
C i ical Ca e Explo a ions www.ccejou nal.o g 7
(Supplemen a y Fig. 3, h p://links.lww.com/CCX/
B57). No signi ican di e ences we e obse ed in any
o he analyzed compounds in absolu e le els o each
ime poin and o he pe cen age o educ ion a 6 and
24 hou s (Supplemen a y Figs. 3 and 4, h p://links.
lww.com/CCX/B57).
A achidonic Acid Signa u e and Pos ope a i e
Bleeding
Based on he AA me abolic signa u e obse ed, we
es ed whe he p eope a o y le els o AA we e asso-
cia ed wi h pos ope a i e bleeding. We indeed ound
ha le els o p eope a i e AA we e in e sely co ela ed
wi h pos ope a i e ches ube blood loss a 24h (R =
–0.3957; *p = 0.03) (Fig. 2A). In con as , he pos ope -
a i e blood loss was no co ela ed wi h pla ele coun in
he p eope a i e (R = –0.04; p = 0.815), a 6 hou s (R =
–0.098; p = 0.597) o a 24 hou s (R = –0.06; p = 0.741).
Conside ing pa ien s wi h a signi ican pos ope a i e
blood loss (a leas 600 mL in he i s 12 hou s a e
su ge y), he p eope a i e le els o AA we e conside -
ably lowe (4.8 x 108 s 6.8 x 108; *p = 0.032) (Fig. 2B).
The subjec s wi h low le els o p eope a o y AA ( i s
qua ile o no signi ican bleeding) had inc eased isk
o pos ope a i e bleeding wi h a ela i e isk 2.8 (95%
CI, 1.19–6.68) and odds a io 7 (95% CI, 1.35–30.25)
(*p = 0.045). Among indi iduals wi h p eope a i e le -
els o AA below 5 × 108, he pos ope a i e blood loss
(600 cc; IQR, 325–600 s 350 cc; IQR, 300–400; *p =
0.029) was subs an ially highe (Fig. 2C).
Fu he mo e, he ans usion a e was also highe in
pa ien s wi h educed p eope a i e AA le els and wi h a
pos ope a i e educ ion. In pa ien s wi h p eop AA le -
els below 5 × 108 ion coun , 42% equi ed pos ope a i e
ans usion, e sus 22% in pa ien s wi h highe le els (p
= 0.418) (Fig. 3A). Addi ionally, pa ien s wi h educed
le els o AA a 6 hou s also had a highe a e o ans u-
sion, compa ed wi h hose wi h unchanged o inc eased
alues (40% s 28%; p = 0.489) (Fig. 3A). Rega ding o he
ou comes in pa ien s wi h pos ope a i e bleeding, he ne-
cessi y o hemodynamic suppo was highe , al hough
no s a is ically signi ican , as well as mechanical en ila-
ion o mo e han 6 hou s and neu ologic complica ions
(Table1). In e es ingly, pos ope a i e a ial ib illa ion was
mo e common in he g oup wi hou signi ican bleeding.
AA was la e e alua ed o p edic i e accu acy o
iden i ying pa ien s wi h an inc eased isk o signi i-
can bleeding. F om he ecei e ope a ing cha ac-
e is ic cu e, AA was a p edic o o pos ope a i e
signi ican bleeding wi h an AUC o 73.2% (Fig. 3B).
As CPB is associa ed wi h a sys emic in lamma o y
esponse, we also measu ed IL-6 le els (Supplemen a y
Fig. 5A, h p://links.lww.com/CCX/B57) and co e-
la ed hem wi h pos ope a i e AA a iabili y (Fig. 3C).
We obse ed a s ong co ela ion be ween IL-6 le els
and he AA a iabili y ( = –0.602; ***p = 0.0004), sug-
ges ing a possible ole o he in lamma o y se ing in
AA me abolism pe u ba ion. Cu iously, IL-6 le els
we e lowe in pa ien s wi h signi ican pos ope a i e
bleeding (Supplemen a y Fig. 5B, h p://links.lww.
com/CCX/B57).
Figu e 3. A, Pos ope a i e ans usion a e conside ing p eope a i e a achidonic acid quan i ica ion and he educ ion in pe cen age a
pos ope a i e 6 h . B, Recei e ope a ing cha ac e is ic cu e based on he p eope a i e a achidonic acid measu emen s and ep esen ed
by an a ea unde he cu e (AUC) o 0.73 indica ing a sa is ac o y p edic i e abili y. C, Co ela ion be ween human in e leukin 6 le els
and a iabili y in a achidonic acid le els a 6 h pos ope a i e (pe cen change compa ed wi h p eope a i e le els).
Velho e al
8 www.ccejou nal.o g Oc obe 2022 • Volume 4 • Numbe 10
DISCUSSION
Un a ge ed me abolomics o samples collec ed a e
ca diac su ge y wi h CPB iden i ied a signi ican pla e-
le -associa ed signa u e, ela ed o omega-6 a y-acid
oxida ion. Ou esul s sugges an associa ion be ween
AA me abolism pe u ba ion and pos ope a i e bleed-
ing. To ou knowledge, ou s udy is he i s pla ele -
me abolic analysis a e ca diac su ge y wi h CPB.
Al hough pla ele ans usion is widely used o e-
s o e pe iope a i e hemos asis, he decision is mainly
empi ical since he e is no consensus ega ding dose,
igge , and e icacy (18). Fu he mo e, pla ele ans-
usions a e associa ed wi h se e al complica ions, in-
cluding inc eased use o asoac i e d ugs, ex ended
mechanical en ila ion, p olonged s ay in he ICU and
hospi al, inc eased isk o pos ope a i e in ec ion, and
ans usion- ela ed acu e kidney inju y (19, 12, 13). In
ac , in ou s udy, pa ien s wi h pos ope a i e signi i-
can bleeding had highe a es o hemodynamic sup-
po , mechanical en ila ion o mo e han 6 hou s,
and neu ologic complica ions. Addi ionally, pla ele
ans usion is associa ed wi h conside able heal hca e
cos s (21). The e o is now cen e ed on educing he
use o blood p oduc s o dec ease ans usion- ela ed
complica ions and cos s. The e o e, i is essen ial o un-
de s and how ca diac su ge y a ec s pla ele unc ion
and how we can es ablish new s a egies o minimize i .
In e es ingly, polyunsa u a ed a y acids (PUFAs),
such as omega-6 a y-acids, ha e been associa ed wi h
lowe isk o ca dio ascula e en s, especially due o
an i-in lamma o y p op ie ies (22, 23). PUFA may
egula e pla ele ac i a ion enhancing endo helial e-
pai , bu cu en e idence is limi ed. Addi ionally, i
is well es ablished ha AA and i s me aboli es modu-
la e pla ele agg ega ion. AA- igge ed agg ega ion is
signi ican ly dec eased a e CPB (1), bu no p e ious
s udies co ela ed how pe iope a i e le els o AA and
i s me abolism a ec pos ope a i e hemo hage.
AA concen a ion in luences bo h no mal cel-
lula unc ions and he de elopmen o pla ele dys-
unc ion. AA me aboli es ac as local ho mones and/
o signaling molecules in esponse o basal me abo-
lism o upon egula ion by immune esponse s imuli,
such as he p oduc ion o cy okines (24). CPB is as-
socia ed wi h a signi ican sys emic in lamma o y
esponse, wi h a complex and incomple ely unde -
s ood c oss- alk be ween in lamma ion and coagula-
ion (24, 25). I is known ha endo helial dys unc ion
du ing CPB induces he p oduc ion o cy okines and
pla ele -induc ion ac o s (24, 25). Some AA me ab-
oli es, such as 12-HETE, ha e an impo an ole in
immune-media ed pla ele ac i a ion (23). Al hough
no ye comple ely unde s ood, 12-HETE po en ia es
dense g anule sec e ion ia nico inamide adenine di-
nucleo ide phospha e-oxidase ac i a ion (23, 24) and
he ac i a ion o su ace immuno ecep o s (25, 26).
Fu he mo e, pla ele s a e CPB ha e dec eased le -
els o 12-HETE and a dep essed ac i a ion o lipoxy-
genase ac i i y (27, 28), con ibu ing o pos ope a i e
bleeding isk h ough an inna e immuni y-dependen
pe u ba ion o coagula ion ac o s unc ion (29, 30).
In ac , we ha e obse ed ha IL-6 concen a ions
6 hou s a e su ge y a e s ongly co ela ed wi h
he a iabili y in AA le els in ou pa ien s, sugges -
ing ha in lamma ion plays an essen ial ole in pos -
ope a i e AA dys unc ion. In e es ingly, no all he
pa hways o AA-ac i a ion may ha e he same ele-
ance in pos ope a i e bleeding. We ha e seen ha
le els o TxB2 emain s able, consis en wi h p e ious
s udies ha ha e also epo ed ha TxB2 plasma le -
els 1 and 24 hou s a e he ope a ion had e u ned
o p eope a i e alues (12). Fu he mo e, al hough
concen a ions o me aboli es om bo h eicosanoids
and lipoxygenase pa hways we e educed a 6 and 24
hou s, he educ ion emains app oxima ely he same
a 6 and 24 hou s, whe eas he educ ion o he me ab-
oli e ep esen ing lipoxygenase is much p onounced
a 24 hou s. Thus, al hough cyclooxygenase pa hway
may emain unchanged, eicosanoid and lipoxygen-
ase pa hways may be di e en ly dis up ed. Cu iously,
pa ien s wi h signi ican pos ope a i e bleeding had
lowe le els o IL-6, especially beginning 12-hou
pos ope a i e. I has been documen ed ha AA can
induce he elease o IL-6 om in lamma o y cells,
inducing he p oduc ion o acu e-phase p o eins o
balance some o he de imen al e ec s o AA me ab-
oli es in shock (31). IL-6 augmen s pla ele coun
and unc ion, and he h ombo ic po en ial o IL-6 is
g ea e han i s ib inoly ic e ec in hemo hage, es-
pecially in he ea ly s ages o bleeding (32). Ou ob-
se a ion ha IL-6 le els a e lowe in pa ien s wi h
signi ican hemo hage is a possible consequence o
he AA me abolism pe u ba ion. Fu he s udies
a e needed o elucida e how in lamma ion dis u bs
AA me abolism and o be e dissec he molecula
mechanisms in ol ed.
Obse a ional S udy
C i ical Ca e Explo a ions www.ccejou nal.o g 9
The e a e some limi a ions in ou s udy. Al hough
measu emen s co ela e changes be ween di e en
ime poin s o he same pa ien in o de o minimize
con ounding ac o s, ou s udy popula ion is small,
po en ially causing a s a is ical analysis unde powe .
Fu he s udies a e needed o alida e hese indings in
a la ge popula ion and o add ess o he pa hways iden-
i ied in ou analysis, apa om acid AA me abolism.
CONCLUSIONS
In summa y, we show an in lamma o y- ela ed pe u ba-
ion o AA me abolism as a signa u e o ca diac su ge y
wi h CPB and ha p eope a i e le els o AA may be mo e
ele an han pla ele coun o an icipa e and p e en
pos ope a i e blood loss in pa ien s submi ed o ca diac
su ge y wi h CPB, especially when he educ ion a e
CPB is associa ed wi h highe ans usion a e. Pla ele
loss o unc ion is pa ially esponsible o pos ope a-
i e bleeding, and al hough pla ele ans usions a e as-
socia ed wi h less pos ope a i e blood loss, hey inc ease
mo bidi y and mo ali y (20). AA supplemen a ion a
a dose equal o, o lowe han, he die a y in ake is sa e
and inc eases plasma ic le els o AA in a dose-dependen
manne (33). P eope a i e AA adminis a ion may be a
sa e and inexpensi e op ion o educe pla ele dys unc-
ion a e ca diac su ge y wi h CPB, wi h he po en ial o
educe pos ope a i e bleeding and he need o ans u-
sion and should be subsequen ly explo ed.
ACKNOWLEDGMENTS
We hank he con ibu ion and collabo a ion o he
nu ses and all he s a om Ca dio ho acic Su ge y
Depa men in Hospi al de San a Ma ia, Lisboa,
Po ugal.
1 Ins i u o Gulbenkian de Ciência, Oei as, Po ugal.
2 Depa men o Ca dio ho acic Su ge y, Hospi al de San a
Ma ia, Cen o Hospi ala Lisboa No e, Lisbon, Po ugal.
3 Cen o Ca dio ascula da Uni e sidade de Lisboa,
Faculdade de Medicina, Uni e sidade de Lisboa, Lisbon,
Po ugal.
4 Depa men o Ca diology, Hospi al de San a Ma ia, Cen o
Hospi ala Lisboa No e, Lisbon, Po ugal.
5 Vienna BioCen e Co e Facili ies GmbH, Vienna, Aus ia.
Supplemen al digi al con en is a ailable o his a icle. Di ec
URL ci a ions appea in he p in ed ex and a e p o ided in he
HTML and PDF e sions o his a icle on he jou nal’s websi e
(h p://jou nals.lww.com/ccejou nal).
D s. Velho and Fe ei a con ibu ed equally
Suppo ed, in pa , by Ins i u o Gulbenkian de Ciência.
The au ho s ha e disclosed ha hey do no ha e any po en ial
con lic s o in e es .
Fo in o ma ion ega ding his a icle, E-mail: [email p o ec ed]
REFERENCES
1. Robich MP, Koch CG, Johns on DR, e al: T ends in blood u i-
liza ion in Uni ed S a es ca diac su gical pa ien s. T ans usion
2015; 55:805–814
2. Sulli an MT, Co on R, Read EJ, e al: Blood collec ion and ans u-
sion in he Uni ed S a es in 2001. T ans usion 2007; 47:385–394
3. Benne -Gue e o E, Zhao Y, O’B ien SM, e al: Va ia ion in use
o blood ans usion in co ona y a e y bypass g a su ge y.
JAMA 2010; 304:1568–1575
4. LaPa DJ, C osby IK, Ailawadi G, e al: Blood p oduc conse a ion
is associa ed wi h imp o ed ou comes and educed cos s a e
ca diac su ge y. J Tho ac Ca dio asc Su g 2012; 145:796–804
5. Vi acqua A, Koch CG, Yousu AM, e al: Mo bidi y o bleeding
a e ca diac su ge y: Is i blood ans usion, eope a ion o
bleeding, o bo h? Ann Tho ac Su g 2011; 91:1780–1790
6. Boe C, Mees e s MI, Miloje ic M, e al: 2017 EACTS/EACTA
guidelines on pa ien blood managemen o adul ca diac su -
ge y. J Ca dio ho ac Vasc Anes h 2018; 32:88–120
7. Alghamdi AA, Da is A, B is e S, e al: De elopmen and alida-
ion o T ans usion Risk Unde s anding Sco ing Tool (TRUST)
o s a i y ca diac su ge y pa ien s acco ding o hei blood
ans usion needs. T ans usion 2006; 46:1120–1129
8. Kes in AS, Vale i CR, Khu i SF, e al: The pla ele unc ion de-
ec o ca diopulmona y bypass. Blood 1993; 82:107–117
9. Ichikawa J, Osada Y, Kodaka M, e al: Associa ion be ween
pla ele coun and pos ope a i e blood loss in pa ien s unde -
going ca diac su ge y wi h ca diopulmona y bypass and esh
ozen plasma adminis a ion guided by h omboelas ome y.
Ci cul J 2018; 82:677–683
10. Kjellbe g G, Holm M, Lind all G, e al: Pla ele unc ion analysed
by ROTEM pla ele in ca diac su ge y a e ca diopulmona y by-
pass and pla ele ans usion. T ans us Med 2020; 30:369–376
11. Lopes CT, B uno i E, Ca alcan e A: Fac o s associa ed wi h
excessi e bleeding a e ca diac su ge y: A p ospec i e coho
s udy. Hea and Lung 2016; 45:64–69.e2
12. Zilla P, Fasol R, G oscu h P, e al: Blood pla ele s in ca diopul-
mona y bypass ope a ions. Reco e y occu s a e ini ial s im-
ula ion, a he han con inual ac i a ion. J Tho ac Ca dio asc
Su g 1989; 97:379–388
13. Paes AMA, Gaspa RS, Fuen es E, e al: Lipid me abolism and sig-
naling in pla ele unc ion. Ad Exp Med Biol 2019; 1127:97–115
14. Dyke C, A onson S, Die ich W, e al: Uni e sal de ini ion o
pe iope a i e bleeding in adul ca diac su ge y. J Tho ac
Ca dio asc Su g 2014; 147:1458–1463.e1
15. Tibi P, McClu e RS, Huang J, e al: STS/SCA/AmSECT/
SABM upda e o he clinical p ac ice guidelines on pa ien
blood managemen . Ann Tho ac Su g 2021; 112:981–1004
16. R Co e Team: R: A Language and En i onmen o S a is ical
Compu ing. Vienna, Aus ia, R Founda ion o S a is ical
Compu ing, 2021
