Table V. Multivariate Cox Proportional Hazards Model for Incidence of Graft Stenosis.

In this multivariate hazards model, the lowest quartile of preoperative IgM values was significantly associated with graft stenosis requiring intervention.

Variable	Level	Hazard Ratio	Lower 95%	Upper 95%	P-value for Z statistic
Prior Failed	Yes	3.45	0.39	30.83	0.27
High Risk Vein Graft	Yes	3.5	0.47	26.03	0.22
Pre-operative IgM value – quartile	Low 25%	7.79	1.27	47.82	0.027
Log rank test, P = 0.013 for this model