LONG-TERM SURVEILLANCE BY DUPLEX SCANNING OF NONREVISED INFRAGENICULAR GRAFT STENOSIS

To define the prognosis of nonrevised graft stenosis, we studied 68 in fragenicular bypass grafts in patients entered into our duplex surveil lance program between 1986 and 1987. Patients were grouped according t o the grade of stenosis as follows: grade I = <50% stenosis, grade II = 50% to 75% stenosis, and grade III = 75% to 99% stenosis. Time until maximum stenosis was stratified into three intervals (<3 months, betw een 3 and 12 months, and >12 months). Cumulative patency rates from th e time of maximum stenosis to failure were calculated using Kaplan-Mei er analysis. Fifty-three grafts (78%) developed stenoses: 10 with grad e I, 25 with grade II, and 18 with grade III stenosis. Eighty-nine per cent of the 18 graft occlusions occurred within 2 years. Two grafts oc cluded after 2 years without any severe stenosis or preceding clinical signs. During follow-up 15 nonrevised stenosed grafts (four with grad e I, five with grade II, and six with grade III stenosis) remained pat ent longer than 2 years with a mean follow-up of 72 months. Statistica l analysis for graft failure determined that grade II to III stenoses led to graft occlusion significantly earlier than grade 0 to I stenose s (p = 0.017). If graft failures resulting from revision were separate d from the analysis, the time interval from operation to maximum steno sis (within 1 year) remained marginally significant for predicting occ lusion, whereas no correlation was found between the grade of maximum stenosis and occlusion. Thus the prognosis for graft stenosis depends on the grade of stenosis and on the time interval from operation to st enosis. Therefore duplex surveillance seems to be most important withi n the first 24 months only, but is of little use in predicting impendi ng graft failure beyond 2 years in asymptomatic patients.