Development of a Scoring System for the Prediction of Early Graft Failure after Peripheral Arterial Bypass Surgery

Trends in Utilization of Completion Imaging after Lower Extremity Bypass and Its Association with Major Adverse Limb Events and Loss of Primary Patency

BACKGROUND

Failure following lower extremity bypasses (LEBs) isoften secondary to technical defects. Despite traditional teachings, routine use of completion imaging (CI) in LEB has been debated. This study assesses national trends of CI following LEBs and the association of routine CI with 1-year major adverse limb events (MALE) and 1-year loss of primary patency (LPP).

METHODS

The Vascular Quality Initiative (VQI) LEB dataset from 2003-2020 was queried for patients who underwent elective bypass for occlusive disease. The cohort was divided based on surgeons' CI strategy at time of LEB, categorized as routine (≥80% of cases/year), selective (<80% of cases/year), or never. The cohort was further stratified by surgeon volume category [low (<25th percentile), medium (25th-75th percentile), or high (>75th percentile)]. The primary outcomes were 1-year MALE-free survival and 1-year loss of primary patency (LPP)-free survival. Our secondary outcomes were temporal trends in CI use and temporal trends in 1-year MALE rates. Standard statistical methods were utilized.

RESULTS

We identified 37,919 LEBs; 7,143 in routine CI strategy cohort, 22,157 selective CI and 8,619 in never CI. Patients in the 3 cohorts had comparable baseline demographics and indications for bypass. There was a significant decrease in CI utilization from 77.2% in 2003 to 32.0% in 2020 (P < 0.001). Similar trends in CI use were observed in patients who underwent bypass to tibial outflows (86.0% in 2003 vs. 36.9% in 2020; P < 0.001). While the use of CI has decreased over time, 1-year MALE rates have increased from 44.4% in 2003 to 50.4% in 2020 (P < 0.001). On multivariate COX regression, however, no significant associations between CI use or CI strategy and risk of 1-year MALE or LPP was found. Procedures performed by high-volume surgeons carried a lower risk of 1-year MALE (HR: 0.84; 95% CI [0.75-0.95]; P = 0.006) and LPP (HR:0.83; 95% CI [0.71-0.97]; P < 0.001) compared to low-volume surgeons. Repeat adjusted analyses showed no association between CI (use or strategy) and our primary outcomes when the subgroups with tibial outflows were analyzed. Similarly, no associations were found between CI (use or strategy) and our primary outcomes when the subgroups based on surgeons' CI volume were evaluated.

CONCLUSIONS

The use of CI, for both proximal and distal target bypasses, has decreased over time while 1-year MALE rates have increased. Adjusted analyses indicate no association between CI use and improved MALE or LPP survival at 1 year and all CI strategies were found to have equivalent outcomes.

The predictive value of microperfusion assessments for the follow-up of tibial bypass grafts

OBJECTIVE

We conducted a prospective evaluation of microperfusion parameters after tibial bypass surgery was performed. Differences between grafts with occlusions during follow-up and patent grafts were analyzed in relation to the pedal arch quality.

METHODS

Patients receiving tibial bypass grafts for chronic limb-threatening ischemia from 2019 to 2020 were included. Assessment of microcirculation (parameters: hemoglobin oxygen saturation [sO₂] and flow) was done by laser Doppler flowmetry and white light spectrometry (oxygen-to-see), supine and in elevation, whereas the macrocirculation was evaluated by the ankle-brachial index and duplex ultrasound examination. The quality of run-off was graded for each patient. Measurements were performed preoperatively, 1 day postoperatively, and after 6 months. Patients with graft occlusions during follow-up (OCCLUDED) and patients without occlusions (OPEN) were compared.

RESULTS

We included 42 patients (13 women, 29 men; mean age, 76.1 years; range, 60-89 years) were included. The patency of all grafts 1 day after the operation was confirmed by ultrasound examination. The overall analysis of the microcirculation showed significant changes in both the supine and elevated leg position between measurements taken preoperatively, 1 day after the operation, and after 6 months for the parameters sO₂ and FLOW (sO₂ supine, P = .001; sO₂ elevated, P < .001; FLOW supine, P < .001; FLOW elevated, P < .001). The comparison of the values 1 day after the operation yielded significantly decreased microperfusion parameters (both O₂ and FLOW) in the group that developed bypass occlusion in the later follow-up period (sO₂ supine: OCCLUDED, 35.7% [7.3-65.0] and OPEN, 48.7% [25.0-72.3] P = .011; FLOW supine: OCCLUDED, 27.7 A.U. [12.7-52.7] and OPEN, 57.3 A.U. [16.0-106.7], P = .008). No significant differences in the severity of the arch impairment was found between the OPEN and OCCLUDED groups (P = .651). Absolute values of the parameters sO₂ and flow showed no correlation with the pedal arch classification.

CONCLUSIONS

Significantly poorer microperfusion was detected postoperatively in patients with later occurrence of graft occlusions despite patent grafts on the first postoperative day. Microperfusion measurements might be a possible tool for the prediction of graft failure.

External Validation and Evaluation of Reliability of the FARP2 Score to Predict Early Graft Failure after Infrainguinal Bypass

BACKGROUND

To evaluate the accuracy of the FARP₂ (female gender [F], bypass after a previous angioplasty [A], Redo bypass [R], and Pedal bypass [P₂]) scoring system in predicting early graft failure (EGF) after infrainguinal bypass surgery (IBS).

METHODS

Charts of patients who underwent IBS between January 2014 and January 2017 in 2 tertiary academic centers were evaluated retrospectively. In follow-ups, 1 week after operation, detailed physical examination was done, Doppler ultrasonography was performed 1 month after operation, and integrity of the graft was evaluated. Calculation of FARP₂ score was performed by a single surgeon (M.S.) who was well informed regarding FARP₂ scoring system. The FARP₂ scoring system was evaluated as following: female gender 1 point, bypass after a previous angioplasty 1 point, redo bypass 1 point, and pedal bypass 2 points.

RESULTS

Totally, 231 patients (180 men and 51 women) were enrolled in the study. The mean FARP₂ score was 0.52 ± 0.73. The graft occlusion occurred in 23 patients (10%). Presence of critical leg ischemia was lower in patients who faced early graft occlusion (P = 0.002). On the other hand, Rutherford classification score was significantly higher in patients who did not face graft occlusion (4.1 vs. 3.4, P = 0.007). Moreover, unsuccessful angioplasty history and history of previous surgery were more common in that group (P < 0.001 and P < 0.001, respectively). None of the patients faced acute pulse loss, numbness loss, or ulcerative lesion after unsuccessful angioplasty. The mean interval between unsuccessful angioplasty and bypass was 1 ± 1.2 days in our study, which may have a role to prevent undesirable clinical consequences. The FARP₂ score was 1.5 ± 1.2 and 0.4 ± 0.6 in patients who faced graft occlusion and in patients without occlusion (P < 0.001). Multivariate regression analysis identified that critical leg scheme, presence of unsuccessful angioplasty history, and history of previous bypass operation were found as a predictive factor for EGF (P = 0.044, P < 0.001, and P = 0.003, respectively). Finally, our study demonstrated that patients with FARP₂ score 3-4 have 2.88-fold increased graft occlusion risk when compared with patients with FARP₂ score 1-2.

CONCLUSIONS

Our study externally validates that the FARP₂ scoring system is related with EGF after IBS. The FARP₂ score may be an effective practice in prediction of EGF in patients with peripheral arterial bypass surgery.

Prognostic efficacy of circulating asymmetric dimethylarginine in patients with peripheral arterial disease: A meta-analysis of prospective cohort studies

Background Asymmetric dimethylarginine is suggested to be a marker of poor prognosis in patients with atherosclerosis. However, the predictive role of circulating asymmetric dimethylarginine for clinical outcome in patients with peripheral arterial disease has not been determined. Aims To quantitatively assess the predictive value of circulating asymmetric dimethylarginine for clinical outcome in patients with peripheral arterial disease in a meta-analysis of prospective cohort studies. Methods Relevant studies were identified by systematically searching of PubMed and Embase databases. A random-effect model was used to synthesize the results. Sensitivity analyses by omitting one study at a time were performed to evaluate the robustness of the results. Results Six studies with 2535 peripheral arterial disease patients were included. Patients with higher circulating asymmetric dimethylarginine at baseline were associated with higher risk of all-cause mortality (adjusted hazard ratio: 1.63, 95% confidence interval: 1.28-2.06, I² = 16%), and major adverse cardiovascular events (adjusted hazard ratio: 2.01, 95% confidence interval: 1.08-3.73, I² = 78%) as compared with those with lower circulating asymmetric dimethylarginine at baseline. Specifically, every increment of 0.1 µmol/l of asymmetric dimethylarginine was associated with 18% (adjusted hazard ratio: 1.18, 95% confidence interval: 1.06-1.31) increased risk for all-cause mortality and 14% (adjusted hazard ratio: 1.14, 95% confidence interval: 1.04-1.25) increased risk for major adverse cardiovascular disease. Sensitivity analyses by omitting one study at a time did not significantly change the results. Conclusion Higher circulating asymmetric dimethylarginine at baseline may be associated with higher incidence of cardiovascular events and mortality in patients with peripheral arterial disease.