Histopathologic correlates of myocardial improvement in patients supported by a left ventricular assist device.
BACKGROUND
Left ventricular assist devices unload the failing heart and improve hemodynamic function and tissue architecture. In some patients improvement allows for left ventricular assist device removal. We retrospectively compared histologic features in patients who were weaned off left ventricular assist device support with those who remained on support without evidence of clinical remission.


METHODS
We graded left ventricular core samples taken at implantation on a scale we designed for evaluating severity and extent of fibrosis and hypertrophy. We correlated the grades with a computerized semiquantitative analysis of picrosirius-red and Masson's trichrome-stained sections. We evaluated interstitial (10×), perivascular (20×), and replacement (4×) fibrosis. Hypertrophy was assessed by myocyte diameter, cytoplasmic area, and nuclear/cytoplasmic ratio.


RESULTS
All patients (N=17) underwent left ventricular assist device implantation for heart failure. In eight patients improvement allowed left ventricular assist device removal. The groups did not differ in age (24.1 vs. 25 years, P=.4) or mean time on left ventricular assist device support (506 vs. 414 days, P=.24). All mean measures showed significantly less hypertrophy in the left ventricular assist device-removal group than in the nonremoval group, respectively (cytoplasmic area, 58.00 vs. 77.18 μm(2), P=.021; myocyte diameter, 20.32 vs. 25.35 μm, P=.004; nuclear/cytoplasmic ratio, 11.04 vs. 8.69, P=.053). Although not statistically significant, the left ventricular assist device-removal group tended toward less overall fibrosis than the nonremoval group (11.57 vs. 13.24, P=.214).


CONCLUSIONS
Left ventricular assist device-removal patients had less hypertrophy and fibrosis overall than did nonremoval patients. These findings may help identify patients with a higher probability of left ventricular assist device removal and myocardial recovery.
Segura
Ana Maria
AM
Department of Cardiovascular Pathology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, TX 77225-0345, USA. asegura@heart.thi.tmc.edu
Frazier
O H
OH
Demirozu
Zumrut
Z
Buja
L Maximilian
LM
D000328:Adult; D001706:Biopsy; D006332:Cardiomegaly / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D020878:Device Removal; D005260:Female; D005355:Fibrosis; D006333:Heart Failure / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D006353:Heart-Assist Devices; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D020127:Recovery of Function; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013194:Staining and Labeling / Q000379:methods; D013781:Texas; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling; D055815:Young Adult