Usefulness of myocardial performance index in multiple sclerosis mitoxantrone-induced cardiotoxicity

The authors sought to investigate the ability of the Doppler-derived myocardial performance index (MPI) to predict cardiotoxicity in multiple sclerosis (MS) patients under mitoxantrone therapy.

The aauthors prospectively evaluated 28 MS patients (mean age 41±9 years, 12 males and 16 females) treated with low-dose mitoxantrone (basal mean cumulative dose 30±14 mg/m(2), end of follow-up mean dose 41±17 mg/m(2)). All patients underwent two-dimensional and Doppler-echocardiography at baseline and after a mean follow-up of 22±8 months. MPI was estimated using mitral inflow and left ventricular (LV) outflow pattern. Comparing data at baseline and at the end of follow-up, significant decrease in ejection fraction (EF) was observed (60±5 vs 56±4, p<0.03). The MPI was 0.52±0.1 at baseline and 0.60±0.1 at the end of follow-up (p<0.04). Such difference was mainly due to a isovolumic relaxation time prolongation (80±12 at baseline and 98±30 at the end of follow-up, p<0.05). The area under the receiver operating characteristic curve, analysed for an MPI cut-point value of 0.57, in identifying a significant reduction of LVEF ≤50% was of 0.94±0.065 with sensitivity and specificity of 97.5% and 90%, respectively.

In conclusion, it can be speculated that a higher basal value of MPI could represent a subclinical LV cardiotoxicity, identifying a future decrease of EF and a progression to congestive heart failure in MS patients under mitoxantrone therapy.