BASIC FIBROBLAST GROWTH-FACTOR IMPROVES MYOCARDIAL-FUNCTION IN CHRONICALLY ISCHEMIC PORCINE HEARTS

The effect of basic fibroblast growth factor (bFGF) administration on regional myocardial function and blood flow in chronically ischemic he arts was studied in 26 pigs instrumented with proximal circumflex coro nary artery (LCX) ameroid constrictors. In 13 animals bFGF was adminis tered extraluminally to the primal left anterior descending (LAD) and LCX arteries with heparin-alginate beads and 13 other animal served as controls. bFGF-treated pigs showed a fourfold reduction in left ventr icular infarct size compared to untreated controls (infarct size: 1.2 +/- 0.4% vs. 5.1 +/- 1.3% of LV mass, mean +/- SEM, P < 0.05). Percent fractional shortening (% FS) in the LCX area at rest was reduced comp ared with the LAD region in both bFGF and control pigs. However, there was better recovery in the LCX area after rapid pacing in bFGF-treate d pigs (% FSLCX/% FSLAD +/- 22.9 +/- 7.3% --> 30.5 +/- 8.5%, P < 0.05 vs. prepacing) than in controls (16.0 +/- 7.8% --> 143 +/- 7.0%, P = N S). Furthermore, LV end-diastolic pressure rise with rapid pacing was less in bFGF-treated than control pigs (pre-pacing; pacing; postpacing , 10 +/- 1; 17 +/- 3; 11 +/- 1 mmHg vs 10 +/- 1; 24 +/- 4; 15 +/- 1 m mHg, P < 0.05 vs. control). Coronary blood flow in the LCX territory (normalized for LAD flow) was also better during pacing in bFGF-treate d pigs than in controls. Thus, periadventitial administration of bFGF in a gradual coronary occlusion model in pigs results in improvement o f coronary flow and reduction in infarct size in the compromised terri tory as well as in prevention of pacing-induced hemodynamic deteriorat ion.