The risk of amputation and death appears to increase as the number of revascularization procedures increases, according to findings from a retrospective analysis of data.
The amputation risk was present among patients who underwent percutaneous transluminal angioplasty (PTA) only, as well as among subsets of patients who underwent lower extremity bypass (LEB) only, reported Dr. Alexander T. Hawkins of the Center for Surgery and Public Health, Boston, and his colleagues.
Among 11,190 patients with critical limb ischemia who underwent one, two, three, four, or five or more revascularization procedures, the 1-year estimated amputation rates were 23.3%, 27.1%, 30.3%, 26.7%, and 28.6%, and the 1-year estimated mortality rates were 18.7%, 21.1%, 26.3%, 23.6%, and 32.1%, respectively, the investigators reported. The findings were published in the January issue of Annals of Vascular Surgery.
The risk of amputation increased significantly for those with two vs. one revascularization procedures (hazard ratio, 1.22) and for those with three vs. two procedures (HR, 1.33). The risk for death at 1 year also increased significantly among those with two vs. one procedure (HR, 1.18) (Ann. Vasc. Surg. 2014;28:35-47).
Similar trends for amputation were seen in the PTA-only (1: 24.5%; 2: 26.1%; 3: 27.9%; 4: 31.3%; 5+: 26.8%), and LEB-only (1: 26.0%; 2: 32.5%; 3+: 45.5%) groups. "The increases did not appear to be exponential," they noted.
No changes were seen in the PTA-only and LEB-only groups with respect to 1-year estimates of in-hospital death.
A subgroup analysis further showed that timing between procedures was significantly associated with 1-year amputation risk; the risk was 27.2% for a 1-7 day interval, 36.4% for 8 days to 1 month, 19.4% for 1-6 months; and 22.2% for 6 months or more.
"There was also a difference in 1-year amputation rates between bypass patients who underwent bypass first and who underwent PTA followed by bypass" (21.8% vs. 30.7%), the researchers wrote.
Study subjects were adult patients with a mean age of 71 years who underwent revascularization between July 2007 and December 2009. The patients, including 6,225 men (55.9%), were identified from the California State Inpatient Database and had a high burden of comorbidities; 55.2% abused tobacco, 64.9% had coronary artery disease, 51.3% had hypertension, and 68% had diabetes.
Though limited by factors inherent in the use of an administrative database (such as potential inconsistencies in coding accuracy) and in a nonrandomized study (subject to confounding), the findings nonetheless provide "novel and useful information on the increasing risk of amputation and death in patients undergoing multiple revascularization procedures," the investigators said.
They stressed that they are "by no means making the claim that secondary revascularization is inappropriate," but rather, that they are presenting the risks associated with further procedures in an effort to inform the decision-making process.
Critical limb ischemia confers a high risk of limb loss without treatment, they said, noting that 16%-50% of revascularized patients require secondary revascularization. A "major proportion" of these patients will require further procedures, they noted.
"We emphasize continued communication between clinicians and patients on the true risks and benefits of these procedures," they concluded.
Dr. Hawkins and his coauthor, Dr. Stuart Lipsitz, are supported by a grant from the Brigham and Women’s Center for Surgery and Public Health Arthur Tracy Cabot Fellowship. Dr. Hawkins is also supported by the NIH NHLBI T32 Harvard/Longwood Vascular Surgery Training Program. Another author, Dr. Maria J. Schaumeier, is supported by a grant from the Freiwillige Akademische Gesellschaft, Basel, Switzerland.