Abstract
Background
The main obstacle for success after heart transplantation is graft rejection, since is mainly asymptomatic and diagnosed by endomyocardial biopsy (EMB). New echocardiographic technologies could bring benefits to that population if subtle changes in heart mechanics were related to an incipient state of rejection.
Purpose
To quantify echocardiographic parameters of right ventricle strain and volumes by a semi-automated offline software and to identify the presence of any relation between those findings and the histopathologic diagnose of rejection.
Methods
a prospective cohort of 35 postoperative heart transplant patients who were submitted to echocardiographic evaluation up to six hours after EMB, including two-dimensional chamber quantification of left ventricular (LV) volumes and ejection fraction; conventional and tissue Doppler measurements were used for flow and functional analysis. Offline assessment of the right ventricle (RV) was made by TOMTEC software, with the acquisition of RV volumes (EDV, ESV, SV) and ejection fraction, TAPSE, FAC and three-dimensional(3D) RV free wall and septal strain using speckle tracking. EMB results were classified as positive for cellular rejection if graded as 2R (two or more interstitial infiltrate spots and myocyte damage) and positive for humoral rejection if they show any response by immunofluorescence assay.
Results
We studied 35 patients, aged 50 ±11, 21 male (67%), totaling 58 examinations, and then we made two analysis of EMB: one in two groups regarding cellular rejection (53 negative and 5 positive) and other regarding humoral rejection (50 negative and 8 positive). RVEDV was higher in the cellular rejection group (112,5 ± 29,6 ml) compared to those with negative biopsy (86,8 ± 24,7 mL; p = 0,01). RV stroke volume showed a similar behavior (53,5 ± 22,3 mL vs. 34,5 ± 11,3 mL; p < 0,01). Regarding humoral rejection by immunofluorescence, patients who tested positive showed lower RVEDV (79,5 ± 10,5 mL vs. 90,57 ± 27,31 mL; p = 0,02) and RVESV (45,53 ± 6,33 mL vs. 53,87 ± 19,87 mL; p = 0,01). RV free wall strain was lower in the group with positive immunofluorescence (-18,35 ± 2,79% vs. -15,34 ± 5,35%; p = 0,01). Regarding 2D measurements , interventricular septal (11,5 ± 1,06 mm vs. 10,56 ± 1,38 mm; p = 0,02) and left ventricular posterior wall (10,75 ± 1,03 mm vs. 10,04 ± 1,1 mm; p = 0,05) were also thicker in the group with positive immunofluorescence for rejection.
Conclusion
Both cellular and humoral rejection after heart transplantation are associated to increased 3D RV volumes whereas a decrease in RV free wall strain is only observed in humoral rejection; in patients with positive immunofluorescence results a significant increase is seen for septal and posterior wall thickness.
Complement blockade with eculizumab to treat acute symptomatic humoral rejection after heart transplantation
