Temporal course of vessel healing and neoatherosclerosis after DES implantation.

are expensive, potentially dangerous, and current guidelines recommend their use in IPAH, but not in PH-HFpEF, where they are harmful (2). In HFpEF, there is preserved LV systolic function, but impaired diastolic function with abnormal LV relaxation and increased LV filling pressure. Sustained elevations of LV diastolic filling pressures will result in enlargement of the thin-walled left atrium, allowing LAV to be used as a marker of the severity and chronicity of diastolic dysfunction (4). Thenappan et al. (1) noted echocardiographic left atrial enlargement in 64% of their PH-HFpEF group and only 18% of the PAH group, but they used multiple variables requiring clinical, hemodynamic, and echocardiographic data to distinguish between these conditions. We acknowledge that echocardiography will give a measure of LAV, but note the following limitations: 1) echocardiography underestimates CMR-derived LAV, in both healthy subjects and patients with cardiovascular disease; and 2) CMR can be used when acoustic windows are poor (3). We have shown that a single, noninvasive, CMR-derived variable, LAV of <43 ml/m, will distinguish IPAH from PH-HFpEF, which is attractive for busy pulmonary vascular centers.