Digital Calcification was not Associated With Poorer Wound Healing but was Associated With Increased Mortality in Veterans With Peripheral Arterial Disease

In patients with chronic limb-threatening ischemia-related foot wounds, pedal medial arterial calcification (pMAC) scoring has been proposed to predict risk of amputation and mortality. As pMAC scoring is complex (requiring assessment of five imaging regions), we investigated whether a simpler assessment of digital calcification at the hallux where toe brachial indices (TBI) are typically measured would predict outcomes in patients with foot wounds. Following IRB approval, all patients with ABI/TBI performed at a single VA medical center from 10/1/2015-9/31/22 were screened for foot wounds, TBI performed within 3 months of initial wound visit, and ipsilateral foot X ray. Demographics, comorbidities, wound healing, mortality, and amputation were recorded to 12/31/23. Calcification was assessed via pMAC scoring, as well as present vs absent at the hallux (digital calcification [DC]). Patients with and without DC were compared, with sub-analysis by TBI range. Multivariable binary logistic regression was performed in IBM SPSS utilizing the covariates of DC, age, TBI, smoking, CAD, ESRD, CHF, and interval revascularization. Over the study period, 559 Veterans with ABI/TBI studies had foot wounds. 248 had both foot X-ray and associated TBI for 253 total wounds, 75 (30%) with DC. DC was associated with older age (72.6 ± 9.3 vs 69.6 ± 10.9 years; P = .04), ESRD (10% vs 2%; P = .02), CAD (53% vs 32%; P < .01), CHF (35% vs 19%; P =0 .02), interval revascularization (39% vs 23%; P = .02), and higher pMAC score (2.8 ± 1.3 vs 0.5 ± 0.9; P < .01), and inversely associated with smoking (11% vs 29%; P < .01). Those with DC had similar presenting wound length (2.1 ± 2.0 vs 1.7 ± 1.5 cm; P = .08), diabetes (64% vs 57%; P = .33), hypertension (73% vs 67%; P = .38), and prior revascularization (25% vs 18%; P = .23). Time to wound healing without major amputation (31.8 ± 29.9 vs 28.3 ± 28.1 weeks; P = .38), healing (72% vs 77%; P = .26), and major amputation (7% vs 8%; P = 1.00) was similar between groups (Table I). One-year mortality was higher with DC generally (28% vs 11%; P< .01) and for all TBI ranges <0.7. Following adjustment, DC was not associated with impaired wound healing (OR, 1.1; 95% CI, 0.6-2.1), or increased major amputation (OR, 1.1; 95% CI, 0.3-3.6); however, DC remained associated with increased odds for 1-year mortality (OR, 2.3; 95% CI, 1.1-5.0). DC did not predict the ability to heal a foot-level wound; however, following adjustment, it was independently associated with doubled odds for 1-year mortality. Hallux DC scoring should be considered as a potential simpler measurement than pMAC, although further validation studies are required.TableOutcomes of Veteran foot wounds with and without digital calcification by toe-brachial index (TBI) rangeOutcomeTBI rangeDigital calcification (n = 75)No calcification (n = 178)P valueNCount (%)NCount (%)Healed wound without major amputationAll7554 (72)178140 (77).26<0.252012 (60)3124 (77).220.25-0.492719 (70)4836 (75).770.50-0.691412 (86)4839 (81)1.00≥0.701411 (79)5141 (80)1.00Major amputationAll755 (7)17814 (8)1.00<0.25203 (15)312 (6).370.25-0.49272 (7)484 (8)1.000.50-0.69140 (0)485 (10).58≥0.70141 (7)513 (6)1.00Mortality (1-year, all-cause)All7521 (28)17819 (11)< .01<0.25207 (35)315 (16).180.25-0.49277 (26)486 (13).200.50-0.69144 (29)484 (8).07≥0.70143 (21)514 (8).16 Open table in a new tab