Prediction of doxorubicin cardiotoxicity by early detection of subclinical right ventricular dysfunction

Doxorubicin remains one of the most common causes of cardiotoxicity in patients with lymphoma, leading to significant morbidity and mortality. Early decline in left ventricular (LV) ejection fraction predicts chemotherapy-induced cardiotoxicity and mortality, but limited data exist on doxorubicin-induced subclinical right ventricular (RV) dysfunction. We investigated dose-dependent subclinical doxorubicin-induced RV dysfunction in lymphoma patients.

Thirty-five patients with adult lymphoma treated with doxorubicin were studied. All patients had normal baseline LV ejection fraction (LVEF > 55%), and no known cardiopulmonary disease. We studied the dose-dependent effect of doxorubicin on RV strain by 2D speckle-tracking echocardiography (STE) using a vendor-independent software (TomTec). Images were analyzed offline by two independent observers blinded to the clinical characteristics of the study population. Baseline LVEF, RV fractional area change (RV FAC), RV free wall strain (RV FWS), and RV global longitudinal strain (RV GLS) were measured prior to chemotherapy initiation and compared with echo studies obtained at a 6-month follow-up interval. Patients served as their own controls. Comparisons between pre- and post-therapy were achieved using paired Student's t-tests or Chi-Square test.

The Interobserver Intraclass Correlation Coefficient for RV GLS, RV FAC and RV FWS, was 0.87, 0.81 and 0.79, respectively. The mean age was 51 ± 13 years, 40% women, 60% white. The mean cumulative doxorubicin dose was 239 ± 104 mg m^- 2. There was there was significant decline in RV FAC (47.3 ± 4.4% vs. 43.7 ± 3.9%), RV FWS (- 24.9 ± 3.3 vs. -22.2 ± 2.9), and RV GLS (- 22.4 ± 4.1 vs. -20.6 ± 3.4) (all p < 0.01); but no significant decline in LVEF during the 6-month follow up (63.3 ± 6.2% vs. 61.6 ± 11.1%, p = 0.374). At cumulative doxorubicin dose ≥200 mg m^- 2 we found a significant decline in RV FAC (47.0 ± 4.7% vs. 42.2 ± 3.1%, p < 0.01), RV FWS (- 24.6 ± 3.6 vs. -21.5 ± 2.4, p < 0.01), and RV GLS (- 22.3 ± 4.5 vs. -20.1 ± 2.9, p = 0.03).

In this cohort of adult lymphoma patients, doxorubicin-based therapy was associated with subclinical RV dysfunction, but not LV dysfunction, at a cumulative dose ≥200 mg m^- 2. Additional studies evaluating the long-term prognostic implications of RV dysfunction in this population are essential.