RESULTS
During the study period, 36 patients were evaluated for eligibility.
Seven patients were excluded: five because of inadequacy of the sample
taken at T2 (hemolysis) and two because of need for re-entry into CPB
for intraoperative issues. Twenty-nine patients were enrolled over a
four-month period. Seventeen patients were assigned, based on the
surgical approach performed, to the sternotomy group and 12 patients to
the HP group. As shown in Table 1 the two groups were comparable both
for demographic characteristics and type of antithrombotic or
anticoagulant therapies used. Between the beginning (T1) and the end
(T2) of cardiopulmonary bypass we observed an increase of 38.5% (from
1.14 to 1.58) of the INR and of 21.34% (from 0.89 to 1.08) of the aPTT,
as shown in Table 2. At the same time, we observed a decrease in
platelet count, fibrinogen, and AT III, with a median percentage
decrease of 44.33%, 34.82%, and 30.10%, respectively. Between the
beginning and the end of the bypass we also observed a significant
decrease in coagulation factors II, X, XI, XII, protein C and S with an
average percentage decrease of 32.58%, 34.11%, 36.69 %, 47.45%,
33.65% and 30.20%, respectively. We also observed a moderate reduction
for factors V and VII (24.77% and 23.52%) and a modest reduction in
factors VIII and IX (9.81% and 13.51%). Comparing the consumption of
coagulation factors in the sternotomy group and in the HP group we
observed how, at T1, patients belonging to the sternotomy group showed a
statistically significant reduction in Protein C activity compared to
the HP group (96.9 ± 18.9 vs 113.2 ± 21.8 respectively, p = 0.04) and a
statistically insignificant reduction of factor XI activity (101.8 ±
29.6 vs. 122.7 ± 30.9, p = 0.08). (Table 3). Even at T2, the sternotomy
group was characterized by a significant reduction in the activity of
protein C (68.4 ± 12.4 vs. 83.4 ± 15.3, p <0.01) and factor XI
(65, 5 ± 21.1 vs 85.8 ± 24.5, p = 0.024), as well as a higher
consumption of factors V and XII (p = 0.049 and p = 0.07 respectively)
compared to the HP group (Table 4). Table 5 shows the negative
correlation between the duration of CPB and aortic clamping and the
factors consumption. As the duration of CPB and aortic clamping
increases we see a progressive and statistically significant reduction
of factors II, X, XI, XII, Protein C, and Protein S activity. Regarding
viscoelastic parameters, we recorded a median increase of 22.64% of CT
in Intem during CPB (159.0 [146.0-172.0] to 195.50 [189.0 -
248.0] ), with a reduction in MCF in Fibtem of 16.66%, as well as
platelet contribution (MCF Extem - Fibtem), which was reduced by 7.69%
(Table 6). Comparing sternotomy group and HP group 2 (Table 7), CT
elongation at T2 appeared to be more pronounced in patients undergoing
sternotomy compared with those undergoing minithoracotomy (233.70 ± 59.9
vs. 200.3 ± 35.9, p= 0.046). The same was observed for platelet
contribution (MCF Extem-Fibtem) at T2, although not statistically
significant (p=0.052) Finally, we investigated differences in terms of
post-CPB transfusion needs between sternotomy and HP group . We observed
a greater need for transfusion of PRBCs and FFP in the sternotomy group
compared with HP group (p =0.02 and 0.047, respectively) as shown in
Table 8.