Cryopreserved Homografts in Infected Infrainguinal Fields Are Associated with Frequent Reinterventions and Poor Amputation-Free Survival

Cryopreserved arterial allografts vs autologous vein for arterial reconstruction in infected fields

OBJECTIVE

Peripheral arterial infections are rare and difficult to treat when an in situ reconstruction is required. Autologous vein (AV) is the conduit of choice in many scenarios. However, cryopreserved arterial allografts (CAAs) are an alternative. We aimed to assess our experience with CAAs and AVs for reconstruction in primary and secondary peripheral arterial infections.

METHODS

Data from patients with peripheral arterial infections undergoing reconstruction with CAA or AV from January 2002 through August 2022 were retrospectively analyzed. Patients with aortic- or iliac-based infections were excluded.

RESULTS

A total of 42 patients (28 CAA, 14 AV) with a mean age of 65 and 69 years, respectively, were identified. Infections were secondary in 31 patients (74%) and primary in 11 (26%). Secondary infections included 10 femoral-femoral grafts, 10 femoropopliteal or femoral-distal grafts, five femoral patches, four carotid-subclavian grafts, one carotid-carotid graft, and one infected carotid patch. Primary infection locations included six femoral, three popliteal, and two subclavian arteries. In patients with lower extremity infections, associated groin infections were present in 19 (56%). Preoperative blood cultures were positive in 17 patients (41%). AVs included saphenous vein in eight and femoral vein in six. Intraoperative cultures were negative in nine patients (23%), polymicrobial in eight (21%), and monomicrobial in 22 (56%). Thirty-day mortality occurred in four patients (10%), two due to multisystem organ failure, one due to graft rupture causing acute blood loss and myocardial infarction, and one due to an unknown cause post-discharge. Median follow-up was 20 months and 46 months in the CAA and AV group, respectively. Graft-related reintervention was performed in six patients in the CAA group (21%) and one patient in the AV group (7%). Freedom from graft-related reintervention rates at 3 years were 82% and 92% in the CAA and AV group, respectively (P = .12). Survival rates at 1 and 3 years were 85% and 65% in the CAA group and 92% and 84% in the AV group (P = .13). Freedom from loss of primary patency was similar with 3-year rates of 77% and 83% in the CAA and AV group, respectively (P = .25). No patients in either group were diagnosed with reinfection.

CONCLUSIONS

CAAs are an alternative conduit for peripheral arterial reconstructions when AV is not available. Although there was a trend towards higher graft-related reintervention rates in the CAA group, patency is similar and reinfection is rare.

The Effect of Different Thawing Rates on Cryopreserved Human Iliac Arteries Allograft's Structural Damage and Mechanical Properties

Introduction

The rate of thawing of cryopreserved human iliac arteries allografts (CHIAA) directly affects the severeness of structural changes that occur during this process.

Method

The experiment was performed on ten CHIAA. The 10% dimethylsulphoxide in 6% hydroxyethyl starch solution was used as the cryoprotectant; all CHIAA were cooled at a controlled rate and stored in the vapor phase of liquid nitrogen (-194°C). Two thawing protocols were tested: (1) placing the CHIAA in a water bath at 37°C, and (2) the CHIAA were thawed in a controlled environment at 5°C. All samples underwent analysis under a scanning electron microscope. Testing of the mechanical properties of the CHIAA was evaluated on a custom-built single axis strain testing machine. Longitudinal and circumferential samples were prepared from each tested CHIAA.

Results

Ultrastructural analysis revealed that all five CHIAA thawed during the thawing protocol 1 which showed significantly more damage to the subendothelial structures when compared to the samples thawed in protocol 2. Mechanical properties: Thawing protocol 1—longitudinal UTS 2, 53 ± 0, 47 MPa at relative strain 1, 27 ± 0, 12 and circumferential UTS 1, 94 ± 0, 27 MPa at relative strain 1, 33 ± 0, 09. Thawing protocol 2—longitudinal ultimate tensile strain (UTS) 2, 42 ± 0, 34 MPa at relative strain 1, 32 ± 0, 09 and circumferential UTS 1, 98 ± 0, 26 MPa at relative strain 1, 29 ± 0, 07. Comparing UTS showed no statistical difference between thawing methods.

Conclusion

Despite the significant differences in structural changes of presented thawing protocols, the ultimate tensile strain showed no statistical difference between thawing methods.

Comparison of Cryopreserved Arterial Allografts Versus Heparin-bonded Vascular Grafts in Infragenicular Bypass for Chronic Limb Threatening Ischemia

BACKGROUND

The purpose of this study was to compare cryopreserved arterial allograft (CAA) to heparin-bonded prosthesis (HBP) in infragenicular bypasses for patients with chronic limb-threatening ischemia (CLTI).

METHODS

This retrospective study took place in 2 university hospitals and included 41 consecutive patients treated for CLTI. In the absence of a suitable saphenous vein, an infragenicular bypass was performed using either CAA (24 cases) or HBP (17 cases). Kaplan-Meyer analysis compared primary and secondary patency and amputation-free survival rates. Binomial logistic regression analyzed risk factors for major amputation and thrombosis.

RESULTS

The mean followup was 18.5 months (±14.3) in the CAA group, 17.6 (±6.1) in the HBP group. In the CAA group, primary and secondary patency rates at 12 months were 52% (±10.6) and 61% (±10.3), compared to 88% (±7.8) and 94% (±5.7) in the HBP group, respectively. The difference in patency rates was not statistically different (P = 0.27 and P = 0.28, respectively). The statistically significant factors of graft thrombosis were, a stage 4 from the WIfI classification (Wound Ischemia foot Infection) with a 6 times higher risk (P = 0.04), and a distal anastomosis on a leg artery with a 9 times higher risk of thrombosis (P = 0.03). Amputation-free survival rates at 18 months were similar between the groups (CCA: 75% (±9) versus HBP: 94% (±6), P = 0.11). Patients classified as WIfI stage 4 had 13 times higher odds to undergo major amputation than patients with WIfI stage 2 or 3 (95% CI, 1.16-160.93; P = 0.04). The intervention was longer in the CCA group of 74 min (278 min ± 86) compared to the HBP group (203 min ± 69). This difference was statistically significant (95% CI, 17.86-132.98), t(35) = 2.671, P = 0.01.

CONCLUSIONS

CCA is not superior to HBP in infragenicular bypasses for CLTI, and may not be worth the extra cost and the longer operative duration.