THE EFFECT OF BASIC FIBROBLAST GROWTH-FACTOR ON THE BLOOD-FLOW AND MORPHOLOGIC FEATURES OF A LATISSIMUS-DORSI CARDIOMYOPLASTY

Previous studies designed to determine whether latissimus cardiomyopla sty could be used to revascularize ischemic myocardium showed that aft er operation the latissimus was ischemic and had severely deteriorated , This study was undertaken to determine whether basic fibroblast grow th factor, a potent angiogenic peptide, would improve the vascularity of the latissimus and enhance collateral formation between the muscle of the cardiomyoplasty and ischemic myocardium. In goats, myocardial i schemia was induced with an ameroid constrictor and cardiomyoplasty pe rformed. The latissimus was continuously stimulated electrically at 2 Hz for 6 weeks and given four weekly bolus injections of human recombi nant basic fibroblast growth factor (80 mu g infused into the left sub clavian artery). In eight animals, rates of regional blood flow were m easured and both the heart and latissimus were evaluated histochemical ly. The latissimus blood flow rate was 0.114 +/- 0.029 ml/gm per minut e, which was three times greater than that of historical controls (chr onically stimulated latissimus cardiomyoplasty without basic fibroblas t growth factor treatment; 0.042 +/- 0.007 ml/gm per minute, p < 0.05) . Associated with the improved blood flow, there was significantly les s evidence of skeletal muscle fiber dropout and muscle fibrosis in the animals treated with basic fibroblast growth factor. Latissimus-deriv ed collateral flow to ischemic myocardium developed in five of the eig ht goats and averaged 0.288 +/- 0.075 ml/gm per minute. This flow was 42.8% +/- 15.7% (n = 5) of the flow required by normal myocardium (whi ch was 0.728 +/- 0.095 ml/gm per minute). This value for latissimus-de rived collateral blood flow was almost twice that of the historical co ntrols (24.0% +/- 3.9%), but the increase did not achieve statistical significance (p = 0.08). These results hold the promise that basic fib roblast growth factor treatment might enhance the formation of extramy ocardial collaterals to the heart and improve skeletal muscle function .