3. Cytometry will also be performed on the 14 day visit. As in our first IRB submission, each patient serves as his/her own control. Two "pairs" of blood specimens will be analyzed per patient. A "pair" includes phlebotomy prior to and immediately after two hours of PPCD. The first pair is obtained on enrollment in the CRC. The second pair will be done 2 weeks later 18-24 hours after the last dose of G-CSF. The patient will return for standard of care clinical evaluation, with repeat hemodynamic testing 6 months after that 14 day CRC evaluation.