NPPB and obstructive sleep apnea syndrome: However, the AHI and PASP in the overlap syndrome group were higher than those in the OSAHS group; the right ventricular structure and function parameters (such as RVTD, right atrial transverse diameter, TNI, BNP) in the overlap syndrome group were worse than that in the OSAHS group(p < 0.05), as shown in Figure 2.