TR access is associated with endothelial injury and intimal hyperplasia.
Kamiya noted intimal hyperplasia (the primary method of long-term saphenous vein graft failure) in 68% of RAs in the prior RA catheterization group and 39% in those from the control group (P=0.046). Gaudino 7
examined 50 patients who underwent TR coronary angiography before CABG and split the patients into 3 groups depending on the time interval. Immunohistochemical analysis demonstrated extensive endothelial injury in all examined RAs, with a trend toward a reduction in damage over time.
Nitroglycerin-mediated dilation (NMD) and flow-mediated dilation (FMD) are frequently used to study vasomotor function of the RA. Burstein found that, although the NMD response showed some trend for recovery over time, the FMD response was almost completely abolished after 9 weeks.8 Yan demonstrated that TR procedures decreased RA NMD and FMD resulting in immediate and persistent blunting of vasodilatory function.9
Using ultrasound imaging, studies have shown that the diameter of the RA following TR intervention never completely returns to baseline.10 A meta-analysis by Rashid found that, following TR intervention, the incidence of RA occlusion within 24 hours was 7.7%, which decreased to 5.5% at >1 week follow-up.11. The only intervention that significantly reduced the risk of occlusion was use of a higher dose of heparin (5,000 IU vs < 5,000).