There are multiple definitions:

1. inorganic pyrophosphate(English)

   • an endogenous inhibitor of soft tissue calcification, and implicated in the mechanism of aortic valve calcification
   • ABCC6, ALP, AS, ATP, AVC, AVCS, BMI, CCTA, DM, ENPP1, eGFR, GACI, HMGCR, HTN, LDL-C, Pi, Pi/PPi, PXE, TNAP
   • Calcium, Cardiology, Pathology
   • https://doi.org…3/ehjci/jeaf247

2. pulse pressure index(English)

   • calculated as PP/SBP
   • CKiD, AASI, CKD, CVD, DBP, ESRD, hs-CRP, iGFR, LVMI, PP, SBP
   • Kidney and adrenals, Pediatrics, Hemodynamics, Biomarker, Ratio-based metric
   • https://doi.org….1111/jch.13905