WASHINGTON, D.C.—Percutaneous declotting of hemodialysis grafts less than 30 days from initial placement may result in shorter secondary patency compared with declotting of older grafts, according to researchers.


“The pressure from surgeons has been to show them the paper to prove that this doesn’t work, and that paper has never been out there,” said senior study author Scott Trerotola, MD, chief of interventional radiology and a professor of radiology at the University of Pennsylvania in Philadelphia.

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“So that is the impetus to do the study: to support the long-term contention that you shouldn’t do this. The results of percutaneous declotting are very poor [in the first 30 days], and we are saying it should not be done. You may find mechanical problems such as kinks, anastomotic problems and small vessels that are difficult or impossible to fix percutaneously.”


Percutaneous declotting usually is not performed for hemodialysis access grafts thrombosing within the first 30 days after initial placement for safety reasons and the possibility of underlying causes that may require surgical correction.


He and his colleagues analyzed acute and long-term outcomes of declotting of grafts with early failure in 860 percutaneous mechanical thrombectomies. Of these, 23 were performed in grafts that were less than 30 days old (U30 group).


The investigators identified 15 percutaneous thrombectomies performed in grafts 31-60 days after placement (U60 group). The researchers analyzed immediate technical and clinical success rates for the percutaneous declots, complications of the procedures, and subsequent graft patency and survival.


The U30 group was 52% male and had a mean age of 57 years. The U60 group consisted was 27% male and had a mean age of 61.7 years. The groups did not differ in graft material, location, configuration or inflow/outflow.


The researchers observed no significant difference in primary patency between the two groups. The mean primary patency rate was seven days for the U30 group and 16 for the U60 group. Secondary patency did differ significantly, however. It was 17 days in the U30 group compared with 82 days in the U60 group.


The investigators observed a nonsignificant trend toward increased graft survival in the U60 group compared with the U30 group (mean survival 149 vs. 38 days). The investigators reported their findings at the Society for Interventional Radiology’s 33rd Annual Scientific Meeting.


Similar technical success rate

These differences in observed patencies could not be explained by differential rates of procedural complications or underlying graft problems between the two groups. The technical success rate was statistically equivalent between the two groups (74% in the U30 group and 80% in the U60 group). 


Reported complications included one pseudo-aneurysm and one venous rupture. Both of these were in the U30 group and both resulted in loss of access. In addition, underlying surgical problems with the grafts, such as kinks and small arteries and veins, were identified at similar rates between the two groups (36% in the U30 grafts and 33% in the U60 grafts). 


Overall, the immediate technical success rate and the 90-day primary patency in both groups fell short of recommendations from the National Kidney Foundation’s Kidney Disease Outcome Quality Initiative.


“We think these findings are clin-ically significant because they suggest that there is something different about the grafts that are thrombosing within the first 30 days of placement and that it would be beneficial to send those patients back for a surgical thrombectomy and possible surgical revision,” said co-investigator Alexandra Yurkovic, a medical student at the University of Pennsylvania.


Complications related to dilation of fresh anastomosis and surgical technical problems do not appear to be the cause of the poor results following percutaneous intervention, she noted. Factors resulting in poor technical success and low subsequent patencies in percutaneous thrombectomy of early-thrombosing access grafts still need to be identified.