Sunday, March 28, 2004
FISTULA OR MISTULA....
About the only good thing that can be said about dialysis access surgery is that one can perform the operation while sitting down. HD access, for good or ill, makes up a large portion of our practice at Acme Surgical Corp. These patients can be a challenge to manage, both from a technical and physiologic standpoint. The National Kidney Foundation has as one of their projects something called the Kidney Disease Outcome Quality Initiative (KDOQI). Part of the KDOQI is a set of practice guidelines. (You may draw your own conclusions about Amgen's sponsorship of guidelines that advocate use of a great deal of Epoetin.) One set of these guidelines sets out recommendations for HD access. The guidelines are extensive. Their main point is that arterio-venous fistulas should be the access of choice due to their better long-term patentcy rates. The goal of these programs is to increase the rate of fistula creation to 50 percent as a first access, and to 40 percent as a secondary access. The rates in the US now are 20-30 percent with Canada, Europe, and Japan having fistula rates between 70-90 percent. What role the HD populations in those countries (and the more widespread use of HD in the US) play in that figure is not addressed in the Fistula First material.
There is a great deal of emphasis on preoperative evaluation of the inflow and outflow vessels, including vein mapping and arterial duplex studies (to ensure an outflow vein >2.5mm in diameter and an artery diameter >2mm). If at all possible I construct fistulas but given the limitations described above, not all patients qualify. As with most things surgical, each procedures have their advantages and disadvantages. Fistulas have greater long-term patentcy (I have seen fistulas that have been working for over ten years), are associated with lower long-term costs due to their patentcy, and, particularly with radio-cephalic wrist fistulas, easier to construct. On the other hand fistulas take longer to mature, actually have poorer early patentcy rates than grafts, may fail to mature, and have few surgical options when they do thrombose. Grafts mature earlier, allow for larger areas for cannulation, are easier to cannulate, allow for a more "customized" route of access, and are very amenable to surgical correction (declotting and revision) should problems arise. The problem with grafts are their durability. About fifty percent will fail and require revision in two years. Obviously this is a problem given the costs associated with graft failure. The KDOQI program is a sound strategy for managing dialysis access with strong emphasis on quality and evidence-based methods...except for this.
The weak point in their emphasis on fistula creation lies with what is one of the foundations of the system, outcome improvement. Much is made of patentcy rates of grafts over time, but when it comes to monitoring fistulas:
GUIDELINE 35
Primary Access FailureÂNative AV Fistulae
No guideline for primary access failure is recommended. (Opinion)
Rationale To achieve the proposed goal of attaining native AV fistulae in at least 40% of patients requiring dialysis access (see Guideline 29: Goals of Access PlacementÂMaximizing Primary AV Fistulae), the Work Group recommends that the primary failure rate of AV fistulae not be used as an indicator of quality. To do otherwise might discourage native fistulae construction in patients with more complex vascular anatomy (ie, in patients who are at a higher risk for failure). Nevertheless, primary failure of native AV fistulae should be examined in dialysis centers as part of their QA/CQI vascular access programs.......
GUIDELINE 38
Cumulative Patency Rate of Primary AV Fistulae
No guideline for cumulative access patency is recommended. (Opinion)
Rationale To achieve the proposed goal of attaining native AV fistulae in at least 40% of patients requiring dialysis access, the Work Group recommends that the cumulative patency rate of AV fistulae not be used as an indicator of quality. To do otherwise might discourage native fistulae construction in patients with more complex vascular anatomy who may be at a higher risk for failure. Nevertheless, cumulative patency rates should be examined in dialysis centers as part of their QA/CQI vascular access programs. (emphasis mine)
So what this says to me is that their goal of a higher fistua rate is so important that they would rather have a surgeon place a fistula in a patient that they know by experience has a high possibility of failure than have a surgeon place a primary graft. I am sure that as more surgeons move toward more aggressive placement of fistulas that the patency rates will decline. But doesn't that indicate the need for qualified fellowship-trained vascular surgeons to be the only ones doing dialysis access? It would be, but HD access is the "red-headed stepchild" of vascular surgery. Even among vascular surgery patients dialysis patients are considered difficult and somewhat unsatisfying to take care of. They aren't like carotid or AA patients where you perform an operation and they get better, they are more like a severe peripheral disease patient that requires multiple operations. The vascular surgeons calling for their own board rarely mention HD access as a motivator.
Anyway I have to return to work tomorrow,oh well.... |
About the only good thing that can be said about dialysis access surgery is that one can perform the operation while sitting down. HD access, for good or ill, makes up a large portion of our practice at Acme Surgical Corp. These patients can be a challenge to manage, both from a technical and physiologic standpoint. The National Kidney Foundation has as one of their projects something called the Kidney Disease Outcome Quality Initiative (KDOQI). Part of the KDOQI is a set of practice guidelines. (You may draw your own conclusions about Amgen's sponsorship of guidelines that advocate use of a great deal of Epoetin.) One set of these guidelines sets out recommendations for HD access. The guidelines are extensive. Their main point is that arterio-venous fistulas should be the access of choice due to their better long-term patentcy rates. The goal of these programs is to increase the rate of fistula creation to 50 percent as a first access, and to 40 percent as a secondary access. The rates in the US now are 20-30 percent with Canada, Europe, and Japan having fistula rates between 70-90 percent. What role the HD populations in those countries (and the more widespread use of HD in the US) play in that figure is not addressed in the Fistula First material.
There is a great deal of emphasis on preoperative evaluation of the inflow and outflow vessels, including vein mapping and arterial duplex studies (to ensure an outflow vein >2.5mm in diameter and an artery diameter >2mm). If at all possible I construct fistulas but given the limitations described above, not all patients qualify. As with most things surgical, each procedures have their advantages and disadvantages. Fistulas have greater long-term patentcy (I have seen fistulas that have been working for over ten years), are associated with lower long-term costs due to their patentcy, and, particularly with radio-cephalic wrist fistulas, easier to construct. On the other hand fistulas take longer to mature, actually have poorer early patentcy rates than grafts, may fail to mature, and have few surgical options when they do thrombose. Grafts mature earlier, allow for larger areas for cannulation, are easier to cannulate, allow for a more "customized" route of access, and are very amenable to surgical correction (declotting and revision) should problems arise. The problem with grafts are their durability. About fifty percent will fail and require revision in two years. Obviously this is a problem given the costs associated with graft failure. The KDOQI program is a sound strategy for managing dialysis access with strong emphasis on quality and evidence-based methods...except for this.
The weak point in their emphasis on fistula creation lies with what is one of the foundations of the system, outcome improvement. Much is made of patentcy rates of grafts over time, but when it comes to monitoring fistulas:
GUIDELINE 35
Primary Access FailureÂNative AV Fistulae
No guideline for primary access failure is recommended. (Opinion)
Rationale To achieve the proposed goal of attaining native AV fistulae in at least 40% of patients requiring dialysis access (see Guideline 29: Goals of Access PlacementÂMaximizing Primary AV Fistulae), the Work Group recommends that the primary failure rate of AV fistulae not be used as an indicator of quality. To do otherwise might discourage native fistulae construction in patients with more complex vascular anatomy (ie, in patients who are at a higher risk for failure). Nevertheless, primary failure of native AV fistulae should be examined in dialysis centers as part of their QA/CQI vascular access programs.......
GUIDELINE 38
Cumulative Patency Rate of Primary AV Fistulae
No guideline for cumulative access patency is recommended. (Opinion)
Rationale To achieve the proposed goal of attaining native AV fistulae in at least 40% of patients requiring dialysis access, the Work Group recommends that the cumulative patency rate of AV fistulae not be used as an indicator of quality. To do otherwise might discourage native fistulae construction in patients with more complex vascular anatomy who may be at a higher risk for failure. Nevertheless, cumulative patency rates should be examined in dialysis centers as part of their QA/CQI vascular access programs. (emphasis mine)
So what this says to me is that their goal of a higher fistua rate is so important that they would rather have a surgeon place a fistula in a patient that they know by experience has a high possibility of failure than have a surgeon place a primary graft. I am sure that as more surgeons move toward more aggressive placement of fistulas that the patency rates will decline. But doesn't that indicate the need for qualified fellowship-trained vascular surgeons to be the only ones doing dialysis access? It would be, but HD access is the "red-headed stepchild" of vascular surgery. Even among vascular surgery patients dialysis patients are considered difficult and somewhat unsatisfying to take care of. They aren't like carotid or AA patients where you perform an operation and they get better, they are more like a severe peripheral disease patient that requires multiple operations. The vascular surgeons calling for their own board rarely mention HD access as a motivator.
Anyway I have to return to work tomorrow,oh well.... |
