HGF and angina pectoris: Heeschen et al. [30] found that high HGF serum levels in patients with refractory unstable angina were associated with low incidence of death and nonfatal myocardial infarction at six-month follow-up; although in this study, patients with higher HGF levels had more frequently collateral circulation and partial or complete retrograde filling in coronary angiogram study.