The combination of
aspirin and
dipyridamole is currently used to prevent intimal
hyperplasia and to improve long-term vein graft patency following
myocardial revascularization. Preliminary studies indicate that
cod-liver oil, rich in
eicosapentaenoic acid, an
unsaturated fatty acid, may also be effective in the prevention of intimal
hyperplasia. Twenty-four mongrel dogs were used to compare the effectiveness of
aspirin-
dipyridamole and
cod-liver oil on vein graft intimal
hyperplasia following arterial bypass. Forty-eight segments of undistended autologous external jugular vein were interposed between bilaterally divided femoral arteries. All animals received a 2%
cholesterol diet for 1 week before and 6 weeks after operation. Eight controls received the diet alone. Eight other animals received
dipyridamole (2.5 mg per kilogram of
body weight) two days before operation and
dipyridamole (2.5 mg/kg) and
aspirin (30 mg/kg) daily for 6 weeks after operation. Another 8 animals received
cod-liver oil containing 1.8 gm of
eicosapentaenoic acid daily 1 week before and for 6 weeks following operation. Serum
cholesterol increased similarly in all groups; it rose from 4.5 +/- 0.2 mm/L to 8.3 +/- 0.8 mm/L in the controls, to 7.2 +/- 0.5 mm/L in the
aspirin-
dipyridamole group, and to 7.1 +/- 0.5 mm/L in the
cod-liver oil group (p less than 0.01). Prothrombin time, partial thromoboplastin time, total platelet counts, and bleeding times were unchanged. Intimal
hyperplasia was measured at 6 weeks with a Zeiss computerized microscope; 376 +/- 25 measurements were made from each graft. The intima increased from 4.5 +/- 0.2 to 83 +/- 10 micron in the control dogs.(ABSTRACT TRUNCATED AT 250 WORDS)