Evaluating the Impact of Medial Arterial Calcification on Outcomes of Infrageniculate Endovascular Interventions for Treatment of Diabetic Foot Ulcers

BACKGROUND

Medial arterial calcification (MAC) of the tibial and pedal arteries has been associated with an increased risk of amputation among people with diabetes. Endovascular interventions on infrageniculate vessels are frequently performed with the intent of treating peripheral artery disease (PAD) and decreasing the risk of amputation in those with diabetes. This study aimed to investigate how the extent of MAC impacts outcomes of endovascular procedures in people with diabetic foot ulcers (DFU).

METHODS

We identified all patients who had undergone infrageniculate angioplasty in the setting of DFU at our institution between 2009 and 2019. Subjects were assigned a MAC score based on the severity of MAC in each vessel visualized on plain radiographs of the ankle and foot. We evaluated the relationship between MAC and the primary outcome, major adverse limb event (MALE), using stratified Cox proportional modeling.

RESULTS

Among 99 subjects with DFU who had undergone infrageniculate angioplasty, MALE occurred in 50% (95% confidence interval [CI] 38%-61%) of patients within 1 year of intervention. On univariate Cox regression analysis, each 1 point increment in MAC score (hazard ratio [HR], 1.09; 95% CI 1.01-1.18), the third tertile of MAC score (HR, 2.27; 95% CI 1.01-5.11), age (HR 0.96; 95% CI 0.93-0.99), and wound grade (HR, 5.34; 95% CI 2.17-13.14), were significantly associated with increased risk of MALE. On adjusted analysis stratified by wound grade, MAC score was found to be associated with MALE only in patients with a low wound grade.

CONCLUSION

Increased severity of MAC is associated with increased risk of MALE for subjects undergoing infrageniculate angioplasty with a low wound grade. Further research is needed to better understand the complex relationships of MAC, PAD, DFU, and interventions aimed at promoting healing of DFU.

The impact of chronic kidney disease on lower extremity bypass outcomes in patients with critical limb ischemia

OBJECTIVE

Patient selection for open lower extremity revascularization in patients with chronic kidney disease (CKD) remains a clinical challenge. This study investigates the impact of CKD on early graft failure, postoperative complications, and mortality in patients undergoing lower extremity bypass for critical limb ischemia.

METHODS

The National Surgical Quality Improvement Program database was queried for all patients with critical limb ischemia from 2012 to 2015 who underwent lower extremity bypass using the targeted vascular set. The glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration Study equation. CKD categories were determined from the National Kidney Foundation Kidney Disease Outcomes Quality Initiative staging criteria. Patients were classified into three groups: CKD stages 3 or lower (mild to moderate CKD), CKD stages 4 or 5 (severe CKD), and on hemodialysis (HD). Multiple variable analysis was used to examine graft failure, mortality, and postoperative complications.

RESULTS

The Surgical Quality Improvement Program database identified 6978 patients who underwent infrainguinal lower extremity arterial bypass during the study period. There were 6101 patients (87.4%) with mild to moderate CKD, 327 (4.7%) with severe CKD, and 550 (7.9%) on HD. Patients with severe CKD and on HD were more likely to have revascularization for tissue loss (54.9% vs 68.8% and 74.7%; P < .01). Patients with severe CKD and those on HD had higher rates of early graft failure, postoperative myocardial infarction, and rates of reoperation. Multiple variable analysis confirmed these results showing that HD was associated with postoperative myocardial infarction, readmission, and increased mortality. It also demonstrated that severe CKD was associated with graft failure (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.12-2.50; P = .01), postoperative myocardial infarction (OR, 2.16; 95% CI, 1.35-3.45; P < .01), and readmission (OR, 1.38; 95% CI, 1.06-1.80; P = .02). Other factors associated with graft failure include functional status (OR, 1.39; 95% CI, 1.08-1.80; P = .01), African American race (OR, 1.72; 95% CI, 1.39-2.13; P < .01), and distal bypass (OR, 1.33; 95% CI, 1.09-1.61; P < .01).

CONCLUSIONS

CKD is a significant predictor of perioperative morbidity after lower extremity bypass. Patients with severe CKD have worse postoperative outcomes without increased mortality. Those on HD have worse survival and postoperative outcomes.