Evaluation of paramalleolar and inframalleolar bypasses in dialysis- and nondialysis-dependent patients with critical limb ischemia

Learning curve in tibial and pedal bypass with autologous vein graft

OBJECTIVES

The 2019 Global Vascular Guidelines recommended open bypass for patients at average risk with greater limb severity and anatomical complexity. However, the outcomes of tibial and pedal bypass (TPB) are inferior to those of above-the-knee surgical revascularization. This may be due to the technical difficulty and need for development of skills to perform TPB. However, there is a limited knowledge on the learning curve in TPB. Thus, the aim of the study is to assess this learning curve in a single-center retrospective analysis.

METHODS

Cases treated with TPB with an autologous vein conduit in patients with chronic limb-threatening ischemia (CLTI) at a Japanese single center from 2009 to 2022 were analyzed retrospectively. The primary endpoint was the learning curve for TPB.

RESULTS

The study included 449 TPB procedures conducted by a single main surgeon in patients with CLTI (median age, 75 years; 309 males; diabetes mellitus, 73%; end stage renal failure with hemodialysis, 44%). The operative time decreased significantly as the number of cases accumulated (p < .001). Using the cumulative sum (CUSUM) operative time, the learning curve was estimated to be phase 1 (initial learning curve) for 134 cases (1-134); phase 2 (competent period) for 179 cases (135-313); and phase 3 (mastery and challenging period) for 136 cases (314-449). The mean follow-up period was 34 ± 31 months. The 1- and 3-year limb salvage rates of 97% and 96% in phase 3 were significantly higher than those in phases 1 and 2 (p < .001, p = .029). Major adverse limb events (MALE) occurred in 117 (26%) patients, and the 1- and 3-year MALE rates of 10% and 17% in phase 3 were significantly lower than those in phases 1 and 2 (p < .001, p = .009).

CONCLUSIONS

In the study, vascular surgeon required a learning curve of 134 TPB cases to Overcoming the learning curve for bypass was associated with improvement of medium-term outcomes for limb salvage and freedom from MALE.

Validation of JCLIMB, SPINACH, and VQI Calculators for Prediction of Two Year Survival in Patients With Chronic Limb Threatening Ischaemia After Infra-Inguinal Surgical or Endovascular Revascularisation

OBJECTIVE

This study aimed to evaluate three survival prediction models: the JAPAN Critical Limb Ischaemia Database (JCLIMB), Surgical Reconstruction Versus Peripheral Intervention in Patients With Critical Limb Ischaemia (SPINACH), and Vascular Quality Initiative (VQI) calculators.

METHODS

Multicentre data of patients who underwent infrainguinal revascularisation for chronic limb threatening ischaemia between 2018 and 2021 were analysed retrospectively. The prediction models were validated using a calibration plot analysis with the intercept and slope. The discrimination was evaluated using area under the curve (AUC) analysis. The observed two year overall survival (OS) was evaluated by the Kaplan - Meier method. The two year OS predicted by each model at < 50%, 50 - 70%, and > 70% was defined as high, medium, and low risk, respectively.

RESULTS

A total of 491 patients who underwent infra-inguinal revascularisation were analysed. The rates of surgical revascularisation, endovascular therapy, and hybrid therapy were 26.5%, 70.1%, and 5.5%, respectively. The average age was 75.6 years, and the percentages of patients with diabetes mellitus and dialysis dependent end stage renal disease were 66.6% and 44.6%, respectively. The tissue loss rate was 85.7%. The intercept and slope were -0.13 and 1.18 for the JCLIMB, 0.11 and 0.82 for the SPINACH, and -0.15 and 1.10 for the VQI. The AUC for the two year OS of JCLIMB, SPINACH, and VQI were 0.758, 0.756, and 0.740, respectively. The observed two year OS rates of low, medium, and high risk using the JCLIMB calculator were 80.1%, 61.1%, and 28.5%, respectively (p < .001), using the SPINACH calculator were 81.0%, 57.0%, and 38.1%, respectively (p < .001), and using the VQI calculator were 77.8%, 45.8%, and 49.6%, respectively (p < .001).

CONCLUSION

The JCLIMB, SPINACH, and VQI survival calculation models were useful, although the OS predicted by the VQI model appeared to be lower than the observed OS.

Effect of gait speed on clinical outcomes after crural and pedal bypass in patients with chronic limb-threatening ischemia

OBJECTIVES

Many factors affect long-term outcomes after open bypass in patients with chronic limb-threatening ischemia (CLTI). Ambulatory status has been suggested to be associated with clinical outcomes, but there is limited knowledge on the effect of gait speed on outcomes. The purpose of this study is to evaluate the effect of gait speed assessed in a 6-min walk test (6MWT) on outcomes after crural and pedal bypass in patients with CLTI.

METHODS

A retrospective analysis was performed in patients with CLTI who underwent a 6MWT at 1 month after crural and pedal bypass at a single center from 2014 to 2021. Comparisons were made between those with high gait speed (HG group, 6-min walk distance (6MWD) > 288 m) and those with low gait speed (LG group, 6MWD ≤288 m). The primary endpoint was survival, and the secondary endpoints were graft patency, limb salvage, wound healing, major adverse cardiovascular events (MACEs), and hospital outcomes.

RESULTS

Of 104 patients with CLTI who underwent a 6MWT after crural and pedal bypass, 46 (44%) and 58 (56%) were placed in the HG and LG groups, respectively. The LG group was older (p < .001), had more female subjects (p = .006), and had a higher prevalence of cerebrovascular disease (p = .042) and tissue loss (p = .007). The median follow-up was 36 (22-57) months. The HG group had significantly higher 3-year primary patency (65% vs 42%, p = .013), 3-year secondary patency (87% vs 66%, p = .018), 3-year overall survival (89% vs 58%, p < .001), and 3-year freedom from MACE (79% vs 67%, p = .039). The 3-year limb salvage and 12-month wound healing rates did not differ between the groups.

CONCLUSIONS

Gait speed in patients with CLTI after crural and pedal bypass was associated with survival, freedom from MACE, and graft patency but not with limb salvage and wound healing. A detailed study of walking ability in these patients may be needed in the future.

Comparison of limb outcomes between bypass surgery and endovascular therapy in dialysis-dependent and -independent patients with chronic limb-threatening ischemia

OBJECTIVE

To examine limb salvage (LS) and wound healing in dialysis-dependent and -independent patients with chronic limb-threatening ischemia (CLTI) after infrainguinal bypass surgery or endovascular therapy (EVT).

METHODS

We retrospectively analyzed the multi-center data of patients who underwent infrainguinal revascularization for CLTI with Wound, Ischemia, and foot Infection (WIfI) stage 2 to 4 between 2015 and 2020. The primary endpoint was LS. The secondary endpoint included wound healing, amputation-free survival (AFS), periprocedural complications, and 2-year survival. Comparison of these outcomes were made after propensity score matching.

RESULTS

We analyzed 252 dialysis-dependent (318 limbs) and 305 dialysis-independent (354 limbs) patients. Propensity score matching extracted 202 pairs with no significant differences in characteristics. The LS rate in bypass surgery was better than that in EVT in dialysis-dependent patients (P < .001). There was no significant difference in the LS rates between bypass surgery and EVT in dialysis-independent patients (P = .168). The wound healing rate of bypass surgery was better than that of EVT both dialysis-dependent and -independent patients with CLTI. The AFS rate of bypass surgery was better than that of EVT in dialysis-dependent patients (P < .001). There was no significant difference in the AFS rates between bypass surgery and EVT in dialysis-independent patients (P = .099). There was no significant difference in the occurrence of Clavien-Dindo ≥ IV and V between bypass surgery and EVT in dialysis-dependent and -independent patients. Age ≥75 years, serum albumin levels <3.5 g/dL, and non-ambulatory status were risk factors for 2-year mortality in dialysis-dependent patients. The 2-year survival rates in dialysis-dependent patients with risk factors of 0, 1, 2, and 3 were 82.5%, 67.1%, 49.5%, and 10.2%, respectively (P < .001).

CONCLUSIONS

For LS and wound healing, bypass surgery was preferred for revascularization in dialysis-dependent patients with WIfI stage 2 to 4. Although dialysis dependency was one of the risk factors for 2-year mortality, dialysis-dependent patients, who have 0 to 1 risk factors, may benefit from bypass surgery, as 2-year survival of >50% is expected.

A Systematic Review and Meta-Analysis on Sex-Based Disparities in Patients with Chronic Limb Threatening Ischemia Undergoing Revascularization

BACKGROUND

This systematic review and meta-analysis sought to describe the prognostic implications of sex on the clinical outcomes of patients undergoing interventions for chronic limb threatening ischemia (CLTI).

METHODS

Studies were systematically searched across 7 databases from inception to August 25, 2021 and rerun on October 11, 2022. Studies focusing on patients with CLTI undergoing open surgery, endovascular treatment (EVT), or hybrid procedures were included if sex-based differences were associated with a clinical outcome. Two independent reviewers screened studies for inclusion, extracted data, and assessed risk of bias using the Newcastle-Ottawa scale. Primary outcomes included inpatient mortality, major adverse limb events (MALE), and amputation-free survival (AFS). Meta-analyses were performed using random effects models and reported pooled odds ratio (pOR) and 95% confidence interval (CI).

RESULTS

A total of 57 studies were included in the analysis. A meta-analysis of 6 studies demonstrated that female sex was associated with statistically higher inpatient mortality compared to male sex undergoing open surgery or EVT (pOR, 1.17; 95% CI: 1.11-1.23). Female sex also demonstrated a trend toward increased limb loss in those undergoing EVT (pOR, 1.15; 95% CI: 0.91-1.45) and open surgery (pOR 1.46; 95% CI: 0.84-2.55). Female sex also had a trend toward higher MALE (pOR, 1.06; 95% CI, 0.92-1.21) in 6 studies. Finally, female sex had a trend toward worse AFS (pOR, 0.85; 95% CI, 0.70-1.03) in 8 studies.

CONCLUSIONS

Female sex was significantly associated with higher inpatient mortality and a trend toward higher MALE following revascularization. Female sex trended toward worse AFS. The reasons for these disparities are likely multifaceted on patient, provider, and systemic levels and should be explored to identify solutions for decreasing these health inequities across this vulnerable patient population.

Treatment Outcomes between Bypass Surgery and Endovascular Therapy in Patients with Chronic Limb-Threatening Ischemia classified as Bypass-preferred category based on Global Vascular Guidelines

OBJECTIVE

To examine outcomes between bypass surgery and endovascular therapy (EVT) in patients with chronic limb-threatening ischemia (CLTI), classified as bypass-preferred according to the Global Vascular Guidelines (GVG).

METHODS

We retrospectively analyzed the multi-center data of patients who underwent infrainguinal revascularization for CLTI with Wound, Ischemia, and foot Infection (WIfI) Stage 3-4 and Global Limb Anatomical Staging System (GLASS) Stage III, which is classified as bypass-preferred category by the GVG between 2015 and 2020. The endpoints were limb salvage and wound healing.

RESULTS

We analyzed 301 patients and 339 limbs following 156 bypass surgery and 183 EVT. The 2-year limb salvage rates were 92.2% in the bypass surgery group and 76.3% in the EVT group, respectively (P < .01). The 1-year wound healing rates were 86.7% in the bypass surgery group and 67.8% in the EVT group (P < .01). Multivariate analysis shows decreased serum albumin level (P < .01), increased wound grade (P = .04), and EVT (P < .01) were risk factors for major amputation. Decreased serum albumin level (P < .01), increased wound grade (P < .01), GLASS infrapopliteal grade (P = .02), and inframalleolar (IM) P grade (P = .01), and EVT (P < .01) were risk factors for impaired wound healing. Subgroup analysis of limb salvage in patients after EVT, decreased serum albumin level (P < .01), increased wound grade (P = .03), increased IM P grade (P = .04), congestive heart failure (P < .01) were risk factors for major amputation. According to scoring by existence of these risk factors, 2-year limb salvage rates following EVT were 83.0% and 42.8% for the total score of 0-2 and of 3-4, respectively (P < .01).

CONCLUSIONS

Bypass surgery provides better limb salvage and wound healing in patients with WIfI Stage 3-4 and GLASS Stage III, which is classified as bypass-preferred category by the GVG. In patients after EVT, serum albumin level, wound grade, IM P grade, and congestive heart failure were related to major amputation. Although bypass surgery may be considered as initial revascularization procedure in patients classified as bypass-preferred category, in case that EVT has to be selected, relatively acceptable outcomes can be expected in patients with less these risk factors.

Effectiveness of the Vascular Quality Initiative Chronic Limb-Threatening Ischemia Mortality Prediction Model in Patents with Distal Bypass

BACKGROUND

The purpose of this study is to evaluate the effectiveness of mortality prediction using the Vascular Quality Initiative (VQI) chronic limb-threatening ischemia (CLTI) model in patients with distal bypass.

METHODS

Patients who underwent distal bypass for CLTI from 2009 to 2020 at a single center were retrospectively reviewed. Distal bypass was defined as any bypass with a distal anastomosis to the posterior tibial, anterior tibial, dorsalis pedis, plantar, or peroneal artery. Baseline characteristics, operative details, hospital outcomes, and medium-term outcomes were compared among patients with a low-, medium-, and high-risk of mortality based on a VQI CLTI calculation. The primary endpoints were survival and limb salvage.

RESULTS

A total of 287 distal bypasses were performed in 230 patients (153 males; median age, 74 years; diabetes mellitus, 70%; end-stage renal disease [ESRD] with hemodialysis, 38%). These patients were stratified into 153 (66%) low-, 35 (15%) medium-, and 42 (18%) high-risk cases based on the VQI CLTI model. There were two hospital deaths (1%) within 30 days. During a mean follow-up period of 33 ± 29 months, 105 patients died and 26 limbs (9%) required major amputation. The 2-year survival rate of 81% in the low-risk group was significantly higher than those of 41% in the medium-risk group and 46% in the high-risk group (both P < 0.001). The 2-year survival rates did not differ significantly between the medium- and high-risk groups (P = 0.81). The 2-year limb salvage rate of 93% in the low-risk group was significantly higher than those of 81% in the medium-risk (P = 0.023) and those of 87% in the high-risk (P = 0.039) groups. There were no significant differences in graft patency and wound healing among the three groups.

CONCLUSIONS

These results suggest that distal bypass is optimal treatment for patients with a low VQI-predicted risk of mortality. However, the lower limb salvage and higher mortality rates at 2 years suggest that the decision-making for VQI medium- and high-risk patients may be carefully considered.

Outcomes of Infrapopliteal Bypass for Chronic Limb-Threatening Ischemia are Worse in Renal Transplant Patients than in Hemodialysis-Dependent Patients

BACKGROUND

Comparisons of distal bypass outcomes between hemodialysis-dependent (HD) and renal transplant (RT) patients have been reported, but the influences of immunosuppressive therapy on the outcomes remain unclear because of the limited number of RT patients who underwent distal bypass or cohort heterogenicity. We compared outcomes of distal bypass for chronic limb-threatening ischemia (CLTI) with homogenous ischemic limb pathology.

METHODS

Between January 2014 and December 2019, we performed 334 infrapopliteal bypass procedures using vein grafts for 275 consecutive CLTI patients with tissue loss. Among them, there were 130 HD patients (47.3%) (163 limbs) and 11 RT patients (4%) (15 limbs), and 30-day mortality, 5-year primary and secondary patency (PP and SP), limb salvage (LS), amputation-free survival rates, and wound healing (WH) status were compared between the HD and RT patient groups.

RESULTS

Nine HD patients died within 30 days after surgery (7%), whereas no deaths were observed among the RT patients. Five-year PP and SP rates in the RT group 39% and 41%, which were significantly worse compared to 64% and 82% in the HD group (P < 0.01). Unsuccessful rate of revision surgery including hemodynamically failed grafts after revision reached over 80% in the RT group, which was technically unfeasible pathology for graft salvage (vs. 3% in the HD group), and WH, and LS rates were significantly worse in the RT group.

CONCLUSIONS

In comparison with HD patients, RT patients showed a lower LS rate for CLTI. The lower LS rate was associated with a lower SP rate, which was caused by disease progression of distal arteries in the foot.

The Impact of Chronic Limb-Threatening Ischemia on Cardiac Surgery

Purpose

The effect of chronic limb threatening ischemia (CLTI) on advanced cardiac disease, which requires surgical treatment, has rarely been reported. The purpose of this study was to review the outcomes of cardiac surgery in patients with CLTI and determine the risk factors, with a particular focus on the severity of CLTI.

Patients

The baseline characteristics and outcomes of 33 patients who were treated for CLTI and underwent cardiac surgery were retrospectively analyzed. The states of CLTI were evaluated based on the Wound, Ischemia, and foot Infection (WIfI) classification system, and 33 patients were divided into the low-WIfI group (stages 1–2, n = 13) and high-WIfI group (stages 3–4, n = 20).

Results

The in-hospital mortality rate was 0% in low-WIfI group and 35% in high-WIfI group (p = 0.027). Postoperative complications, particularly severe infections, occurred more frequently among high-WIfI group than low-WIfI group (70.0% vs. 23.1%, p < 0.01). Multivariable analysis identified foot infection grade as a WIfI classification factor and lower albumin levels as factors significantly associated with postoperative complications. The 1-year and 2-year survival rates were 84.6% and 67.7% in low-WIfI group and 45% and 28.1% in high-WIfI group, respectively (p = 0.011).

Conclusions

Cardiac surgery in patients with high WIfI stage was an extremely high-risk procedure. In such patients, lowering the WIfI stage by lower extremity revascularization and/or debridement of diseased parts prior to cardiac surgery can be considered.

Comparison of clinical outcomes, including the wound healing rate, between inframalleolar bypass to the pedal artery and that to the pedal branch artery in the modern endovascular era

OBJECTIVE

Inframalleolar (IM) bypass has been reported to demonstrate acceptable patency and limb salvage in chronic limb-threatening ischemia (CLTI) patients. However, wound healing after IM bypass and comparisons between pedal artery (PA) bypass and pedal branch artery (PBA) bypass are lacking.

METHODS

We reviewed prospectively collected data from 208 consecutive patients after IM bypass performed over a period of six years. Patients were divided into two groups based on the distal anastomotic artery: the PA group (dorsal pedis artery or common plantar artery) and the PBA group (medial tarsal, lateral tarsal, medial plantar, and lateral plantar artery). The primary outcome was wound healing, and secondary outcomes included loss of patency and limb and life prognosis.

RESULTS

Of the 208 patients, 174 (74%) had PA bypass, whereas 34 (16%) had PBA bypass. Patients in the PBA group were significantly younger than those in the PA group (69 ± 7 vs. 73 ± 9, P = .03). Although early (30-day) graft failure was more common in the PBA group, late clinical outcomes, including the wound healing rate (79% in the PA group and 84% in the PBA group, P=.74), were similar between the two groups. The Global Limb Anatomic Staging System (GLASS) IM grade (HR, 0.73; 95% confidence interval [CI], 0.58-0.93: P=.006); wound, ischemia, and foot infection (WIfI) wound grade (HR, 0.67; 95% CI, 0.51-0.89: P<.01); and WIfI foot infection grade (HR, 0.79; 95% CI, 0.65-0.96: P=.02) were independent predictors of wound healing.

CONCLUSIONS

The current study revealed that wound healing in patients following PBA bypass was acceptable and comparable to that following PA bypass. In the modern era, including high prevalence of infrapopliteal angioplasty, our results could provide useful information to clinicians in actual clinical settings. Moreover, PBA bypass may be an alternative revascularization procedure to avoid major amputation when the pedal artery is occluded, such as in the GVG IM P2 grade. Prospective multicenter larger studies are warranted to confirm the findings of this study and to compare PBA bypass and IM EVT in anatomical "no-option" CLTI.

Wound Healing on the Cutting Plane of Ankle Bones after Incomplete Revascularization for Chronic Limb-Threatening Ischemia in an Elderly Patient: A Case Report

Chronic limb-threatening ischemia (CLTI) is an important issue for elderly patients with peripheral artery disease. Here, we present the case of a 91-year-old man with CLTI, residing in a rural district. The onset of CLTI rapidly deprived him of ambulation because of a foot infection. Given that he had difficulty with long-distance transportation, limb salvage for extensive tissue loss was performed at a district facility, based on his and his family’s request. Finally, skin grafting on the cutting plane of the right ankle bones resulted in wound healing in six months after incomplete revascularization and multiple minor amputations.

Collateral artery bypass in the infrapopliteal segment

A 74-year-old man with diabetes and end-stage renal failure on regular dialysis required revascularization for gangrene of multiple toes and a heel ulcer on the right foot with chronic limb-threatening ischemia. However, the anterior tibial artery, posterior tibial artery, and peroneal artery, which are the usual targets below the knee, showed obstruction or calcification and were considered inappropriate bypass targets. Instead, a collateral artery developed along the area of the posterior tibial artery, and bypass surgery was performed with this artery. This is a case report showing successful collateral artery bypass grafting in the distal infrapopliteal segment.

Distal Bypass Grafting Using the Basilic-Cephalic Loop Vein for Chronic Limb-Threatening Ischemia under Peripheral Nerve Blockades in a Patient with Severely-Reduced Heart Function and End-Stage Renal Disease

A 51-year-old man with severe comorbidities required redo revascularization due to left chronic limb-threatening ischemia caused by a previous vein graft occlusion. The saphenous veins were not available due to previous surgeries. Femoro-posterior tibial artery bypass surgery was successfully performed using the basilic–cephalic loop vein under peripheral nerve blockades. This anesthesia allowed a series of surgical revascularizations without general anesthesia, and the postoperative courses were uneventful. The patient survived for 4 years with ambulatory status. In conclusion, loop graft can be an alternative single vein material for distal bypass when no saphenous veins are available.

Laser speckle flowgraphy can also be used to show dynamic changes in the blood flow of the skin of the foot after surgical revascularization

Objectives

Laser speckle flowgraphy is a new method that enables the rapid evaluation of foot blood flow without contact with the skin. We used laser speckle flowgraphy to evaluate foot blood flow in peripheral arterial disease patients before and after surgical revascularization.

Materials and methods

A prospective single-center study. Thirty-one patients with 33 limbs that underwent surgical revascularization for peripheral arterial disease were included. Pre- and postoperative foot blood flows were measured on the plantar surface via laser speckle flowgraphy and skin perfusion pressure. The laser speckle flowgraphy device was used to visualize the blood flow distribution of the target skin and processed the pulse wave velocity of synchronized heart beats. The mean blood flow, which was expressed as the area of the pulse wave as the beat strength of skin perfusion on laser speckle flowgraphy converted into a numerical value, was assessed as dynamic changes following surgery. Beat strength of skin perfusion was also investigated in non-peripheral arterial disease controls (23 patients/46 limbs).

Results

The suitability of beat strength of skin perfusion in non-peripheral arterial disease controls was achieved; the beat strength of skin perfusion value was significantly higher in every area of interest in non-peripheral arterial disease controls compared to that in peripheral arterial disease limbs at the preoperative stage (105.8 ± 8.2 vs. 26.3 ± 8.2; P < 0.01). Although the pulse wave before surgery was visually flat in peripheral arterial disease patients, the pulse wave was remarkably and immediately improved through surgical revascularization. Beat strength of skin perfusion showed a dynamic change in foot blood flow (26.3 ± 8.2 at preoperation, 98.5 ± 6.7 immediately after surgery, 107.6 ± 5.7 at seven days after surgery, P < 0.01 for each compared to preoperation) that correlated with an improvement in skin perfusion pressure.

Conclusions

Laser speckle flowgraphy is a noninvasive, contact-free modality that is easy to implement, and beat strength of skin perfusion is a useful indicator of foot circulation during the perioperative period. Further analysis with a larger number of cases is necessary to establish appropriate clinical use.