Mean platelet volume as a new biomarker for left atrial thrombus or thromboembolic events in nonvalvular atrial fibrillation: Weighing the evidence

Background: Mean platelet volume (MPV) is a new biomarker for left atrial appendage (LAA) thrombus or thromboembolic event with great potential. Considering its applicability and cost, it can be the chosen examination for the detection of LAA thrombus in patients with nonvalvular atrial fibrillation. This study aimed to evaluate MPV as a new biomarker for left atrial thrombus or thromboembolic events in comparison with transesophageal echocardiography. Methods: We did electronic searches on PubMed, ScienceDirect, and SpringerLink databases. Appraisal of studies was performed using critical appraisal sheets provided by the Centre for Evidence-Based Medicine. Test characteristic was extracted from the literature. Meanwhile, sensitivity, specificity, positive predictive value, and negative predictive value (NPV) were calculated based on the test characteristic. Results: Two studies met the selection criteria. Different cutoff was used in the studies (>10.5 fL and >9.4 fL) which showed significant differences in sensitivity, specificity, and positive predictive value. However, both the studies have fairly high NPV (78.95% and 72.65%, respectively). Conclusion: Currently, the best MPV cutoff value in determining the absence of thrombus in the left atrium is 10.5 fL. Although the clinical application of MPV remains limited, it can be further improved by more studies to obtain the optimal cutoff value and to increase the value of MPV by combining with other biomarkers and clinical prediction tools.