Postdoctoral Fellow University of Pittsburgh Pittsburgh, Pennsylvania, United States
Background: Non-invasive myocardial work (MW) is a new method to assess left ventricular function using speckle tracking echocardiography and cuff pressure. This study compares MW in patients undergoing orthotopic heart transplantation (OHT) to healthy controls, evaluates changes over time, and examines the impact of acute cellular rejections (ACRs) on MW.
METHODS AND RESULTS: This single-center retrospective review included OHT patients (2008–2023) and 40 matched healthy controls. Measured myocardial work indices were global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). Routine biopsies were obtained during cardiac catheterization. Nineteen patients (9.8 [IQR: 4.8, 14.5] years at OHT, 44.4% male) were included in this preliminary study. The mean cold ischemia time was 235 ± 53 minutes. In the immediate post-operative period, MW indices were significantly reduced in patients following OHT compared to healthy controls (11.7 [IQR: 8.0, 14.1] years, 52.5% male), (GWI: 1343 [IQR: 1215, 1604] mmHg% vs. 1861 [IQR: 1726, 2034] mmHg%, p< 0.001; GCW: 1663 (365) mmHg% vs. 2231 (232) mmHg%, p< 0.001; and GWE: 94.0 [IQR: 93.0, 95.0] % vs. 96.0 [IQR: 96.0, 97.0] %, p< 0.001). In contrast, GWW was not significantly higher (GWW: 77.0 [IQR: 70.2, 108] mmHg% vs. 67.0 [IQR: 50.2, 87.2] mmHg%, p=0.085). Patients had a mean follow-up of 5.8 ± 3.0 years, during which 234 echocardiography studies with MW indices and 256 cardiac catheterizations were performed. The estimated freedom from 2-year ACR grade 1 was 41.7% (95% CI: 21.3–81.4), while freedom from 2-year ACR grade 2 was 55.9% (95% CI: 37.1–84.2). During follow-up after OHT, GWI (33.1 ± 13.0 mmHg% per year, p = 0.011) and GCW (34.7 ± 13.7 mmHg% per year, p = 0.012) significantly improved, while there were no significant effects on GWW (2.5 ± 1.8 mmHg% per year, p=0.155) or GWE (-0.1 ± 0.1 %, p=0.322). Patients with increasing ACR exhibited significantly deteriorating GWW (interaction p-value=0.012) and GWE (GWE, interaction p-value=0.014), with no significant effects on GWI or GCW (interaction p-values=0.899 and 0.845, respectively).
Conclusion: After OHT, MW was significantly impaired. However, progressive improvement was observed during longitudinal follow-up. GWW and GWE were significantly different in patients with ACRs.
