Many CLI Patients Do Not Receive Revascularization Prior to Amputation

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More than half of patients with critical limb ischemia (CLI) who end up undergoing amputation do not have any surgical or endovascular interventions over the previous year, according to research showing drastic variability in the frequency of such procedures across the country. The findings were published online December 6, 2011, ahead of print in Circulation: Cardiovascular Quality and Outcomes.

Researchers led by Philip P. Goodney, MD, MS, of Dartmouth-Hitchcock Medical Center (Lebanon, NH), reviewed Medicare data from 20,464 patients with peripheral arterial disease (PAD) who underwent major leg amputation between 2003 and 2006. More than half (54%) received no vascular intervention in the year prior to amputation. Of the 46% who did, over one-third (37.4%) received diagnostic endovascular intervention alone, 24.2% received therapeutic endovascular intervention alone, 6.2% received open surgery alone, and 7% received both endovascular intervention and open surgery.

Elderly, Blacks Less Likely to Receive Revascularization

Overall, 25,800 vascular procedures were performed, with 23.3% of patients undergoing 2 to 3 such procedures, and 8.4% undergoing 3. Patients were more likely to undergo 3 or more procedures in the year before amputation if they underwent therapeutic endovascular intervention as opposed to open surgery (68% vs. 39%; P < 0.001), meaning endovascular intervention more often led to repeat revascularization. In addition, patients older than 90 were less likely to undergo a vascular procedure than patients less than 70 (21% vs. 41%; P < 0.001), while black patients were less likely to undergo any revascularization procedure prior to amputation than white patients (32% vs. 37%; P = 0.001).

To examine geographic variation, the researchers looked at the rates of bypass surgery and endovascular intervention within 306 hospital referral regions across the United States, divided by the frequency, or ‘intensity,’ of vascular procedure use. Drastic differences were demonstrated. For instance, in the highest-intensity regions (eg, Elyria, OH; Munster, IN; and Santa Cruz, CA), between 71% and 80% of patients underwent a vascular procedure in the year before amputation, while in the lowest-intensity regions (eg, Sayre, PA; Billings, MT; and Bryan, TX), less than 12% of patients underwent a vascular procedure.

In addition, regions of high frequency of care were widely scattered across the country, demonstrating no geographic patterns. This was true for both open surgery and endovascular intervention. When divided into quintiles of vascular procedure intensity, overall rates of revascularization ranged from 32.6% in the lowest-intensity quintile to 58.4% in the highest-intensity quintile (P < 0.001). These variations were maintained when procedures were stratified by diagnostic endovascular, therapeutic endovascular, and open surgical revascularization.

Variations Largely Unexplained

Variation in intensity was not directly explained by differences in age or race. For example, the differences in revascularization rates across the lowest and highest intensity regions held true for both elderly patients (32.3% vs. 57.9%) and blacks (33.1% vs. 58.1%).

In addition, on multivariable analysis, after adjusting for age, sex, and comorbidities, patients in the highest-intensity regions were still more than twice as likely to undergo revascularization in the year before amputation as patients in the lowest-intensity region (OR 2.4; 95% CI 2.1-2.6; P < 0001).

The researchers conclude that “our analyses demonstrate that aggressive vascular care for patients at risk for amputation has been unevenly applied across the United States. In many regions, . . . most patients with severe PAD undergo amputation without even a diagnostic arteriogram performed in the year before.”

In contrast, they write, “in other regions, patients with a similar extent of PAD undergo a multitude of vascular procedures, especially therapeutic endovascular interventions.”

These variations, the authors note, must be due to differences in regional practice patterns since all patients in the analysis are over age 65 and, therefore, insured by Medicare, eliminating cost as a potential confounder.

Lack of Revascularization Unsurprising—But Unacceptable

Michael R. Jaff, DO, of Massachusetts General Hospital (Boston, MA), commented that he has little trouble believing that revascularization is uncommon in the year prior to amputation. “That didn’t surprise me, and it’s a terrible thing,” he told TCTMD in a telephone interview. “I was actually surprised at how high some of the treatment rates were. I thought many more people go to primary amputation than what they suggested.”

He stressed, though, that even the rates in the high-intensity regions were not that good. “The truth of the matter is that all these patients have critical limb ischemia by definition, so why is the rate only 58% in the high-intensity regions?” Dr. Jaff asked. “That, in my view, is a sad state of affairs, and of course only a third of patients with the same severity of CLI in the very low intensity regions are getting revascularization.”

Physician Attitudes, Training May Play Key Role

He noted that it is understandable how different practice patterns could lead to the wide variation seen in the study. “There are definitely physicians who believe that you ought to just go ahead and amputate the limb, that the chances of saving a leg to functional use to be able to walk on it, particularly in an 85-year-old already on dialysis due to diabetes, are probably not great,” Dr. Jaff said. “Although you don’t know, and I don’t think the United States is ready to just pull the sheets over the leg of that patient.”

Such attitudes may stem from both generational influences and lack of catheter-based training, he added. “I do think the older vascular surgeons who have no endovascular techniques are less likely to go down the path of a long distal bypass, for instance, whereas even a vascular surgeon who’s got really good catheter-based skills is likely to go ahead and give it a shot,” Dr. Jaff said.

Despite the great variability found by the study in terms of high and low-intensity regions, Dr. Jaff noted one troubling trend. “If you look at Mississippi and Alabama and then at the eastern half of South Carolina, they have very low rates of revascularization, and those are the groups that are in the ‘atherosclerosis belt,’” he said. “In my view there is a clustering there, where the population that likely has the greatest risk of CLI is getting the lowest rates of revascularization.”

 

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Source:
Goodney PP, Travis LL, Nallamothu BK, et al. Variation in the use of lower extremity vascular procedures for critical limb ischemia. Circ Cardiovasc Qual Outcomes. 2011;Epub ahead of print.

 

 

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