Runoff Status Research Articles

Impact of Runoff Quality on Superficial Femoral Artery Endovascular Interventions: The Good, the Bad, and the Ugly

Endovascular therapy is the first choice for femoropopliteal occlusive disease treatment in most cases. Multiple factors are known to affect the outcomes of endovascular therapy, including lesion anatomy and distal runoff status. Information regarding the influence of runoff status on the outcomes of superficial femoral artery (SFA) interventions is still scarce and has not been well studied in the current literature. The aim of the present study was to investigate the effect of the runoff score on the outcomes of endovascular SFA interventions.

Outcomes of popliteal artery aneurysms treated by ligation and in-situ saphenous vein bypass.

Modality of elective repair (open or endovascular) of popliteal artery aneurysms (PAAs) is still debated. About open repair no strict evidence exists about the best surgical technique. The aim of this study was to report a 20-year experience with ligation and in-situ saphenous vein bypass for the elective treatment of PAAs. A retrospective review of consecutive patients who underwent elective open surgical PAA repair in our center between January 2001 and April 2020 was performed. Ninety-two limbs in 84 patients underwent a PAA ligation and in-situ saphenous bypass. Early (30 day) outcomes were assessed. Estimated 5-year outcomes according to Kaplan-Meier curves in terms of primary patency, primary assisted patency, secondary patency, and limb salvage were evaluated. Associations of patient and procedure variables with patency and limb salvage outcomes were sought with multivariate analysis. Patients were predominantly male (80/84, 95.2%) with a mean age of 73.1 years (range 50-89). In all cases technical success was obtained. The mean hospital stay was 5.8 days (range 2-27). Thirty-day overall mortality (N.=1) and major amputation (N.=1) rates were both 1.2%. Mean duration of follow-up was 31.3 months (range: 1-168). At 5 years estimated rates of primary patency, primary assisted patency, secondary patency, and limb salvage were 76.3%, 81.5%, 89.9%, and 96.6%, respectively. On multivariate analysis the associations were: primary patency with PAA diameter >30 mm (P=0.007), and poor run-off status (P<0.001); primary assisted patency with poor run-off status (P<0.001); secondary patency with poor run-off status (P=0.04). Major amputation had no independent predictors of poor outcomes. Elective surgical treatment of PAAs with ligation and in-situ saphenous vein bypass is safe, effective and durable with good 5-year outcomes in terms of overall patency and limb salvage. Poor run-off status seemed to be an independent predictor of worse patency rates. This surgical technique should be cautiously applied in patients with PAAs with a diameter >30 mm.

Runoff forecast and analysis of the probability of dry and wet transition in the Hanjiang River Basin

Runoff prediction plays an important guiding role in water resources planning and management, flood and drought prevention. As the Hanjiang River Basin (HRB) is the water source of the middle line of the South-to-North Water Diversion Project, it has higher requirements for water resources accurate prediction. In order to analyze the prediction capabilities of different prediction methods for the HRB runoff, this study constructed 12 prediction models to simulate and predict the runoff of four hydrological stations in the HRB. Furthermore, the Markov Chain Monte Carlo (MCMC) method was used to analyze the transition probability of runoff from low-to-high (high-to-low). The results showed that the runoff of four hydrological stations in the HRB all showed a downward trend, and most of the sudden changes occurred in the 1980 s. The smoother the runoff changes, the easier it is to make accurate prediction. Among the 12 models, the quadric spline Markov forecasting model (QS-MFM), moving average Markov forecasting model (MA-MFM), Markov forecasting model (MFM), deep neural networks (DNN), and cubic exponential smoothing (CES) methods have stronger generalization ability and can more accurately predict the runoff of the HRB. The average relative error during the validation period is 0.27, 0.28, 0.33, 0.34 and 0.39, respectively. The logistic model can accurately simulate the change of runoff status in the HRB. The wet threshold of Baihe (BH), Huanglongtan (HLT), Huangjiagang (HJG), and Huangzhuang (HZ) is 819.9 m3/s, 207.4 m3/s, 1313.9 m3/s and 1681.7 m3/s, and the dry threshold is 480.4 m3/s, 130.6. m3/s, 817.8 m3/s and 1083.4 m3/s, respectively. The MCMC method can accurately estimate the parameters of the logistic model, and the low-high (high-low) runoff transition probability model constructed in the HRB can accurately calculate the low to high (high to low) runoff transition probability.

Popliteal artery patency is an indicator of ambulation and healing after below-knee amputation in vasculopaths.

The posterior flap is a conventional technique for closing a below-knee amputation (BKA) that uses the gastrocnemius and soleus muscle and relies on the popliteal and posterior compartment arteries. If the prior mentioned arterial blood supply is compromised, this flap likely relies on collateral flow. The purpose of this study is to identify and differentiate any significant associations between preoperative popliteal and tibial arterial flow and BKA outcomes and patient-reported function. A retrospective review identified patients from a single tertiary wound care center who received BKAs and angiogram between 2010 and 2017 by a single surgeon. BKA complications, wound healing, and amputee ambulatory status at latest follow-up were all stratified for differences according to baseline tibial vessel run-off (VRO) status, popliteal artery patency, and popliteal angioplasty outcome. Chi-square, Fisher's exact, and Wilcoxon rank sum tests were used with significance defined as p ≤ 0.05. BKAs were performed on 313 patients, of which, 167 underwent preoperative angiography. Thirty-two were excluded due to lack of adequate follow-up leaving a total of 135 patients in the studied population. Diabetes was present in 87%, and 36% had end-stage renal disease. By the study's conclusion, 92% of BKAs had fully healed, with median time-to-healing of 79days (range 19-1314days). 60% of patients were ambulatory at 9.5 months. Higher VRO was associated with higher healing rates and lower complications and time-to-healing. The conversion rate of BKA to above-knee amputation (AKA) was 4%. Preoperative popliteal patency was associated with higher postoperative ambulation rates when compared to patients without popliteal flow preoperatively (patent: 71/109, 65%; occluded: 10/26, 40%; p = 0.02) and independently increased the likelihood of postoperative ambulation. The posterior flap design for BKA works even in the setting of popliteal occlusion. Complication rates are higher in patients with more compromised blood flow, which may ultimately lead to AKA. Given poor ambulation rates in patients who undergo AKA, the results of this study should encourage surgeons to consider a more functional BKA, even in instances when the popliteal artery is occluded.

Autologous saphenous vein and heparin-bonded expanded polytetrafluoroethylene as graft materials for below-the-knee femoro-popliteal bypass in patients with critical limb ischemia: A propensity score-matched analysis

ObjectiveTo compare the outcomes of heparin bonded expanded polytetrafluoroethylene (HePTFE) and autologous saphenous vein (ASV) in patients undergoing below-knee (BK) femoro-popliteal bypass for critical limb ischemia (CLI). DesignRetrospective single-centre matched case–control study. MethodsFrom 2003 to 2019, 275 consecutive BK bypasses for CLI were performed, 109 with the ASV and 166 with a HePTFE graft. All the baseline characteristics that were reliably measured and were potentially relevant in the decision-making process were included as confounders in a logistic regression model and the factors that were significantly different between the two groups then used to perform a propensity matching analysis. Propensity score-based matching was performed in a 1:1 ratio to compare outcomes. Arterial hypertension, hyperlipemia, the need for tibial anastomosis at the distal level and the run-off status were the covariates included in the matching. Follow-up outcomes were estimated by Kaplan–Meier methods and compared with log rank test. ResultsAfter propensity matching, 101 HePTFE bypasses were matched with 101 ASV bypasses. The median duration of follow-up was 37 months (range 1–192). The 5-year survival rate was 67.5% (standard error (SE) 0.05) in the HePTFe group and 64.5% (SE 0.06) in the ASV group (p = 0.8, log rank 0.04). Primary patency rates were 38% (SE 0.06) in the HePTFE group and 41% (SE 0.06) in the ASV group (p = 0.7, log rank 0.3). Also assisted primary patency and secondary patency rates did not differ in the two groups. Amputation-free survival was 53% (SE 0.05) in the HePTFE group and 58% (SE 0.06) in the ASF group (p = 0.6, log rank 0.2). ConclusionsHePTFE provided 5-year similar results to those obtained with use of the ASV in equivalent patients with CLI undergoing below-knee or tibial bypass.

Significance of Distal Runoff Score as a Key Influencer on Clinical Outcomes after Endovascular Interventions for Superficial Femoral Artery Disease

Endovascular therapy (EVT) is being adopted by many surgeons as a suitable first choice in the treatment of most femoropopliteal disease when clinically indicated. However, there are multiple factors affecting the outcome of EVT including the anatomy of lesions and distal runoff status. The evidence of runoff effect on the outcome of superficial femoral artery (SFA) interventions is still scarce and not well studied in the current literature. The aim of this study was to investigate the effect of runoff score on the outcomes of SFA endovascular interventions. Retrospective analysis was carried out on prospectively collected data on patients who underwent SFA endovascular intervention for critical limb ischemia (CLI) in a single tertiary center. Patients with Rutherford categories 4, 5, and 6 who did not have any previous vascular interventions were included in the study. The modified SVS runoff score was used after calculating scores from popliteal and all tibial vessels. Runoff was stratified into good (score <5), compromised (score 5-10), and poor (score >10). Amputation-free survival, patency rates, and overall survival were compared between all groups at 5 years. Between 2011 and 2018, 254 procedures were performed in 220 patients. Technical success was >92%; 66 patients required SFA stents, and 55 had concomitant tibial angioplasty. There was no significant difference between good, compromised, or poor runoff groups regarding complication rates, with 3.5% overall perioperative mortality (5 cases in the compromised group and 4 in the poor runoff group). A runoff score of <5 was associated with significantly marked clinical improvement (P<0.001). Patency rates were significantly worse in the compromised and poor runoff groups, with 5-year cumulative primary patency rates of 80%, 50%, and 22% in the good, compromised, and poor runoff groups, respectively (P<0.001). Amputation-free survival worsened as the runoff got poorer with 98%, 91%, and 78% in the good, compromised, and poor runoff groups, respectively, at 5 years (P<0.001). SFA stenting and concomitant tibial angioplasty led to slight improvement in patency rates in the poor runoff group. Poor runoff with a score of >10 was associated with significantly reduced amputation-free survival and patency rates at 5 years in patients undergoing SFA endovascular intervention for CLI. Patients with a runoff score of <5 showed marked clinical improvement postoperatively when compared with patients with a runoff score of ≥5.

Impact of number of run-off vessels on interwoven nitinol mesh stents patency in the femoropopliteal segment.

ObjectiveTo evaluate the impact of run-off vessels number on the outcomes of Supera stent (Abbott Vascular, Santa Clara, Calif, USA) for treatment of femoropopliteal occlusive disease.MethodsWe retrospectively evaluated the medical records of 188 consecutive patients (mean age 68.2 ± 9.6 years, 100 males) undergone angiography and woven mesh stent implantation in femoral or popliteal arteries or both arterial segments, in our institution between January 1 2014 and January 1 2018. Target lesion revascularization and major adverse limb events at 12-month were evaluated comparing patients with 1-, 2- or 3-run-off vessels in the foot.ResultsInterventional success was achieved in 100%. Stent implantation involved in the femoral site in 56 patients (30.3%), the femoropopliteal in 92 patients (48.9%) and the popliteal site in 40 patients (21.3%). A significant improvement of ankle-brachial index (0.29 ± 0.6 vs. 0.88 ± 0.3, P < 0.001) and Rutherford class (5.3 ± 0.8 vs. 0.7 ± 1.9, P < 0.01) were observed before discharge. The median follow-up duration was 12.3 months (inter quartile range: 11.0 to 13.9). During the follow-up period, 52 patients (27.6%) had clinical events. Primary patency at 12 months was 72.4%. The primary patency significantly increased when the runoff status. Comparing the number of events among patients with different number of run-off vessels, a significant difference (P < 0.001) was observed for patients having one (24.0%) and two run-off vessels (15.0%).ConclusionsThe outcomes of Supera stent in femoropopliteal occlusive disease depend strictly on the number of run-off vessels.

Endovascular Therapy Provides Similar Results of Bypass Graft Surgery in the Treatment of Infrainguinal Multilevel Arterial Disease in Patients with Chronic Limb-Threatening Ischemia in All GLASS Stages

Extensive infrainguinal arterial disease still pose a challenge for technical and clinical success of percutaneous angioplasty. The purpose of this study was to compare the results of concomitant femoropopliteal and infrapopliteal percutaneous angioplasty/stenting (PTA/S) with distal bypass graft surgery (BGS) in patients with chronic limb-threatening ischemia (CLTI). In a single-center retrospective investigation between 2011 and 2017, 668 revascularization procedures for CLTI were reviewed. Concomitant femoropopliteal and infrapopliteal disease was identified in 153 CLTI patients, treated with BGS (48) using autogenous veins as substitute or PTA/S in a single procedure (105). A subgroup of patients with complex, extensive arterial lesions (GLASS stage III) received additional analysis. Primary outcomes were limb salvage and survival. The mean follow-up time was 21.4months. Patients treated with PTA/S were significantly older and with predominance of females, diabetes and chronic kidney disease. Smoking was more common in patients treated with BGS. The BGS group showed a 36-month survival rate of 73.4%, whereas the PTA/S group presented a survival of 61.3% in the same interval (P=0.25). The 36-month cumulative limb salvage rate was 53.3 and 59.7% for BGS and PTA/S, respectively (P=0.24). For GLASS stage III patients, 36-month limb salvage rates were 54.4% for the PTA/S group and 50.2% for the BGS group (P=0.29). Multivariate analysis pointed poor runoff status (all endovascular patients) and diabetes (GLASS III endovascular patients) as risk factors for limb loss. PTA/S and BGS presented similar results of limb salvage and survival in the treatment of concomitant femoropopliteal and infrapopliteal arterial disease in patients with CLTI, even for patients with extensive and complex arterial disease.

Results of infrainguinal revascularization with bypass surgery using a heparin-bonded graft for disabling intermittent claudication due to femoropopliteal occlusive disease

BackgroundThe purpose of this study was to analyze the results of infrainguinal revascularization for disabling intermittent claudication (IC) due to femoropopliteal occlusive disease using bypass graft (BPG) surgery with a heparin-bonded expanded polytetrafluoroethylene (HB-ePTFE) graft. MethodsBetween 2002 and 2016, we performed 1400 BPGs with HB-ePTFE interventions in patients with femoropopliteal occlusive disease, of which IC was an indication in 485 (34.6%) patients. Early major end points were in-hospital mortality and major complications; late major end points were primary patency, freedom from redo bypass, freedom from progression to critical limb ischemia, and freedom from above-knee amputation or prosthetic graft infection. ResultsWe performed 200 (41.2%) above-knee BPGs and 231 (47.6%) below-knee BPGs; 54 (11.1%) BPGs targeted a tibial artery. In-hospital death occurred in two (0.4%) patients. Overall, the major complication rate was 4.3%. The median duration of follow-up was 33 months (range, 1-150 months; interquartile range [IQR], 14-62.8 months); the cumulative follow-up index for survival was 0.75 ± 0.25. During the follow-up, 56 (11.6%) patients died. Estimated primary patency of the BPG was 86.1% ± 1.6% (95% confidence interval [CI], 82.7-88.9) at 12 months, 68.4% ± 2.4% (95% CI, 63.5-72.9) at 36 months, and 57.7% ± 2.9% (95% CI, 52.0-63.2) at 60 months. On multivariate analysis, runoff status (no or one vessel), site of the distal anastomosis (below the knee), and postoperative medical treatment (oral anticoagulants) impaired primary patency. Estimated freedom from redo bypass was 96.1% ± 0.9% (95% CI, 93.9-97.5) at 12 months, 84.8% ± 1.9% (95% CI, 80.7-88.2) at 36 months, and 76.4% ± 2.6% (95% CI, 71.0-81.1) at 60 months. Both the runoff status (no or one vessel) and the diameter of the graft (6 mm) were significantly associated with the need for redo bypass. Freedom from progression to critical limb ischemia was 86.1% ± 2.2% (95% CI, 81.2-89.9) at 60 months. During the follow-up, there were 20 (4.1%) above-knee amputations, which occurred at a median of 33 months (range, 2-107 months; IQR, 14-63 months) after the indexed BPG intervention. Prosthetic graft infection occurred in seven (1.4%) patients, with a median delay from index procedure to presentation with graft infection of 33 months (range, 1-72 months; IQR, 14-62.5 months), resulting in a freedom from prosthetic graft infection rate of 98.2% ± 2% (95% CI, 95.8-99.2) at 60 months. ConclusionsIn patients suffering from lifestyle-disabling IC with long or complex occlusive lesions of the femoropopliteal segment, open BPG surgery with Hb-ePTFE graft had an acceptably low mortality rate. A poor runoff status was a significant predictor of loss of graft patency, especially after a below-knee anastomosis, as was the need for redo bypass. Dual antiplatelet therapy had significantly better results against follow-up thrombosis, and 8-mm grafts showed better freedom from redo bypass compared with 6-mm grafts.

PC166 A Matched Case-Control Study on Open and Endovascular Treatment of Popliteal Artery Aneurysms

This study compared early and late results of open and endovascular management of popliteal artery aneurysm (PAA) in a retrospective single-center matched case-control study. From January 1981 to December 2015, 309 consecutive interventions for PAA were performed in our institution. Data concerning these interventions were prospectively inserted in a dedicated database. A retrospective analysis of such database was performed, and 59 interventions carried out with endovascular repair (ER) were found, while the remaining 250 intervention were open repair (OR). ER was preferred in older asymptomatic patients, while OR was offered more frequently to patients with a thrombosed PAA and a poor run-off status. A one-to-one coarsened exact matching on the basis of all the baseline demographic, clinical and anatomical covariates significantly different between the two treatment options was performed, and two equivalent groups of 56 ERs and ORs were generated. The two groups were compared in terms of perioperative (<30 days) results with χ2 test and of follow-up outcomes with Kaplan-Meier curves and log-rank test. There were no differences between the two groups in perioperative deaths, thromboses, and amputations. The 30-day amputation and death rate was 2% in ER group and 5% in OR group (P = .3). Follow-up was available for 108 patients (96.5% of the study group) with a mean duration of 53 months, significantly different in the two groups (71 months in OR group and 36 months in ER group; P < .001). Estimated 4-year survival rates were 89% (standard error [SE], 0.055) in OR patients and 94% (SE, 0.08) in ER patients (P = .4; log-rank, 0.7). At the same time interval, primary patency rates were 72% (SE, 0.06) in ER group and 75% (SE, 0.07) in OR group (P = .9; log-rank, 0.01). Twenty-two PAA-related reinterventions were performed during follow-up, 11 in each group. Estimated 4-year freedom from reintervention was 85% (SE, 0.06) in OR patients and 66% (SE, 0.08) in ER patients (P = .1; log-rank, 2.1). Secondary patency rates at 48 years were 75% (SE, 0.08) in ER group and 83% (SE, 0.055) in OR group (P = .9; log-rank, 0.02), while the corresponding figures in terms of limb preservation was 94% in both groups (P = .4, log-rank, 0.9), respectively. OR and ER of PAAs provided in this retrospective single-center experience similar perioperative and follow-up results in equivalent groups of patients. There is a trend toward a higher risk of reintervention in ER patients, requiring further analysis and a longer follow-up time.

Incidence, risk factors, treatment and prognosis of popliteal artery embolization in the superficial femoral artery interventions.

ObjectivePercutaneous transluminal angioplasty and stenting (PTA + stent) has gained acceptance as a primary treatment modality for the superficial femoral artery (SFA) diseases. Popliteal artery embolization (PAE) is a severe complication in SFA interventions. The purpose of this study was to evaluate the incidence, risk factors, treatment and prognosis of PAE in primary SFA PTA + stent.MethodsChronic SFA arteriosclerosis cases that underwent primary PTA + stent were reviewed from a retrospectively maintained database. Runoff vessels were evaluated in all cases before and after the interventions for PAE detection. The primary patency, secondary patency and limb salvage rates were calculated using Kaplan-Meier analysis and compared using log-rank analysis. Cox multivariate regression was performed to evaluate predictors of patency and limb salvage rates.ResultsThere were 436 lesions treated in 388 patients with 10 PAE events (2.3%) in total. PAE rate was significantly higher in Transatlantic Inter-Society Consensus (TASC) C/D group compared with TASC A/B group (OR = 8.91, P = .002), in chronic total occlusion (CTO) lesions compared with stenotic lesions (P<.0001), and in group with history of cerebral ischemic stroke (OR = 6.11, P = .007). PAE rates were not significantly affected by age, sex, smoking, hypertension, diabetes, hyperlipidemia and runoff status. The binary logistic regression showed that only the TASC C/D was an independent predictor of PAE (P = .031). The 12-month and 24-month primary patency, secondary patency and limb salvage rates in PAE group showed no significant differences comparing with non-PAE group.ConclusionsPAE is a rare event in primary SFA PTA + stent. TASC C/D lesion, CTO and cerebral ischemic stroke history are risk factors for PAE. PAE is typically reversible by comprehensive techniques. If the popliteal flow is restored in time, PAE has no significant effect on long-term patency and limb salvage rates.

Differences in patterns of peripheral arterial occlusive disease and eligibility for endovascular treatment

To analyze differences in morphological changes in the vascular tree among patients presenting with intermittent claudication (IC) and critical limb ischemia (CLI). In addition, suitability for endovascular treatment was evaluated. Our study included 690 lower extremities with IC or CLI in 500 consecutive patients who were assessed by magnetic resonance angiography (MRA) according to the TASC II classification and in terms of the below the knee run-off status. Multivariable logistic regressions models adjusted for cardiovascular risk factors were used to evaluate differences in arteriosclerotic lesion patterns and eligibility for endovascular treatment. Multivariable analysis showed that compared with IC extremities, CLI extremities have significantly more severe arteriosclerotic lesions at the aortoiliac (p < 0.001), femoropopliteal (p < 0.001), and crural levels (p < 0.001), with a greater risk of multilevel disease (odds ratio [OR], 1.71; 95 % confidence interval [CI] 1.10 - 2.66; p = 0.018). More than 80 % of extremities with IC and more than 50 % of extremities with CLI appeared to be eligible for endovascular treatment in an isolated evaluation of the aortoiliac and femoropopliteal axis. For combined evaluation of the aortoiliac and femoropopliteal axis, the proportion of endovascular suitability (TASC A+B lesions) decreased to 65 % (IC) and 41 % (CLI). For TASC A+B+C lesions, the proportions were 79 % (IC) and 41 % (CLI). Lower extremities with IC and CLI significantly differ in terms of arteriosclerotic lesion morphology and patterns of lesion localization. The majority of IC and CLI extremities appear to be eligible for endovascular treatment. Because of further improvement in endovascular equipment, even more patients will be eligible for treatment.

Scoring for the Legs

Recent expansion of endovascular techniques for the treatment of infrapopliteal artery disease has increased the expectation to realistically provide a safer, easier, quicker and effective therapy for many patients with critical limb ischaemia (CLI). Nevertheless, due to the limited numbers, spread among a variety of different techniques, centres and diseases (extension and severity) and the recent introduction (not allowing to validate durability of the results), these novel approaches have still not proved to substantially improve outcomes and remain under investigation in ongoing studies. Periprocedural risk exposure and predictability of success/ failure for the leg with these new approaches in CLI patients remain largely uncertain. Failure rate of distal leg revascularisation techniques relies on several factors (location, extension and severity of artery lesion, run-off status, plantar arch integrity, calcification, diabetes, local status, infection, gangrene, etc.) or, most likely, on a combination of these. A number of scoring systems have been usefully applied to predict outcome after aortic aneurysm or cardiac surgery, while similar methods are lacking in the more challenging field of revascularisation in the legs, with only a few recently conceived.1 In this issue of EJVES, a Japanese experience from Iida et al. proposed a new anatomical score to predict the 2-year major adverse limb event (MALE), defined as freedom from major amputation or any re-intervention after angioplasty of isolated infrapopliteal lesions in patients with CLI.2 By using this score system adopted from cardiac experience (SYNTAX angiographic score for coronary vessel)3 and thereby including only anatomical predictability criteria, the authors were able to individuate limbs with infrapopliteal lesions at high likelihood of unsuccessful endovascular treatment. According to Iida et al. lesion calcification, target vessel diameter 300 mm and no below-the-ankle run-off were positively associated with MALE by multivariate analysis. Over a total of 1057 infrapopliteal angioplasty procedures, freedom fromMALE at 2 years rates were 59% in limbs with only one of these adverse risk factors, but only 29% for limbs with three or four adverse predictors. Even though the authors tested exclusively simple balloon angioplasty and nomore sophisticated techniques for infrapopliteal revascularisation, their system scoremay help identify legs with CLI that can improve less from endovascular therapy and should be

A multicenter comparison between autologous saphenous vein and heparin-bonded expanded polytetrafluoroethylene (ePTFE) graft in the treatment of critical limb ischemia in diabetics

The aim of this study was to evaluate early and follow-up results of below-knee bypasses performed using a bioactive heparin-treated expanded polytetrafluoroethylene (ePTFE) graft in diabetic patients with critical limb ischemia (CLI) in a multicenter retrospective registry involving seven Italian vascular centers and to compare them with those obtained in patients operated on with autologous saphenous vein (ASV) in the same centers in the same period of time. Over an 8-year period, ending in 2009, a heparin-bonded prosthetic graft (Propaten Gore-Tex; W. L. Gore & Associates Inc, Flagstaff, Ariz) was implanted in 180 diabetic patients undergoing below-knee revascularization for CLI in seven Italian hospitals (group 1). In the same period in these seven centers, 133 below-knee bypasses with ipsilateral ASV in diabetics with CLI were performed (group 2). Data concerning these interventions were retrospectively collected in a multicenter registry with a dedicated database. Early (<30 days) results were analyzed in terms of graft patency, major amputation rates, and mortality. Follow-up results were analyzed in terms of primary and secondary graft patency, limb salvage, and survival. The interventions consisted of below-knee bypasses in 132 cases in group 1 (73%) and in 45 cases in group 2 (33%; P < .001); 48 patients in group 1 (27%) and 88 patients in group 2 (67%; P < .001) had distal tibial anastomosis. Patients in group 1 had more frequently adjunctive procedures performed at distal anastomotic sites to improve run-off status. Postoperative and long-term medical treatment consisted of single antiplatelet therapy in 93 cases (52%) in group 1 and in 64 cases (48%, P = ns) in group 2, of double antiplatelet therapy in 18 cases (10%) in group 1 and in four cases (3%; P = .05) in group 2 and of oral anticoagulants in 69 patients in group 1 (38%) and in 65 (49%; P = .02) in group 2. Mean duration of follow-up was 28.3 ± 21.4 months; 308 patients (98%) had at least one postoperative clinical and ultrasonographic examination and 228 (72%) reached at least a 1-year follow-up. Estimated 48-month survival rates were 76.6% in group 1 and 72.7% in group 2 (P = > .9, log-rank 0.08). Primary patency rate at 48 months was significantly better in group 2 (63.5%) than in group 1 (46.3%; P = .03, log-rank 4.1). Assisted primary patency rates at 48 months were 47.3% (SE 0.05) in group 1 and 69% (SE 0.05) in group 2 (P = .01, log-rank 6.3). The rates of secondary patency at 48 months were 57.5% in group 1 and 69.6% in group 2 (P = .1, log-rank 2.3); the corresponding values in terms of limb salvage and amputation free-survival rates were 75.4% and 82.4% (P = .3, log-rank 1), and 59.9% and 64.4% (P = .3, log-rank 0.9), respectively. Data from this large, retrospective registry confirmed that the indexed heparin-bonded ePTFE graft provides satisfactory early and midterm results in diabetic patients undergoing surgical treatment of CLI. While autologous saphenous vein maintains its superiority in terms of primary patency, secondary patency rates are not statistically different, even in the presence of a trend for improved secondary patency with vein graft; and also limb salvage rates are comparable.

Results With Viabahn-Assisted Subintimal Recanalization for TASC C and TASC D Superficial Femoral Artery Occlusive Disease

Many investigators including TransAtlantic Inter-Society Consensus (TASC) recommend against primary endovascular treatment for severe (TASC C and D) superficial femoral artery (SFA) disease. Vein bypass is preferable but may not be appropriate due to comorbidities or lack of suitable vein. This study reviews our results with Viabahn stent graft-assisted subintimal recanalization (VASIR) for TASC C and D SFA atherosclerosis. In all, 13 males and 14 females, mean age 72 ± 11 years underwent 28 VASIR for severe (TASC C 8 of 28, TASC D 20 of 28, and 5 of 28 no continuous infrapopliteal runoff artery) SFA disease. Indications were claudication (14 of 28 limbs), ischemic rest pain (6 of 28), and tissue loss (8 of 28). Viabahn stent graft-assisted subintimal recanalization was chosen instead of bypass due to comorbidities or lack of vein. Patients received aspirin and, if not already taking warfarin, they also received clopidogrel. Patients were examined with Ankle-brachial Index (ABI) and duplex scan at 1 month, then every 3 months after VASIR. Viabahn stent graft-assisted subintimal recanalization was technically successful in all. Ankle-brachial Index averaged 0.47 ± 0.17 preprocedure, 0.89 ± 0.20 postprocedure, and increased by 0.15 or more in every case. Median follow-up is 20 months. There were 3 perioperative (<30 days) and 7 later failures including revision prior to any thrombosis. One patient required amputation. Four have died, 2 with patent grafts, none from causes related to VASIR, all more than 30 days post-VASIR. Estimated 1-year primary and secondary patency were 70% ± 11% and 73% ± 10%. Failure was not significantly associated with indications, comorbidities, or runoff status. There was a clear distinction between patients with early failure and the rest of the patients. None of the 8 patients with failure in the first 8 months after surgery has a patent graft. However, of 17 grafts primarily patent at 8 months, only 2 have failed (1 thrombosed and 1 required preemptive balloon angioplasty). There was a strong trend toward better patency with 6 and 7 mm diameter compared to 5 mm diameter stent grafts. Furthermore, although warfarin was not prescribed as part of the protocol, no patient taking warfarin before and who resumed warfarin after VASIR (n=4) suffered failure. Despite significant early failures, we found VASIR to be durable in those who did not have early failure. Viabahn stent graft-assisted subintimal recanalization is an acceptable alternative to vein bypass in selected patients with severe SFA disease. Smaller arterial or stent graft diameter may be associated with poorer results. Warfarin may be valuable to reduce the risk of failure after VASIR.

Lesion types and device characteristics that predict distal embolization during percutaneous lower extremity interventions

Distal embolization (DE) during percutaneous lower extremity revascularization (LER) may cause severe clinical sequelae. To better define DE, we investigated which lesion types and treatment modalities increase the risk for embolization. A prospective registry of LER from 2004 to 2009 was reviewed. All cases with runoff evaluated before and after intervention were included. Angiograms and operative reports were reviewed for evidence of DE. Interventions included percutaneous transluminal angioplasty (PTA), with or without stent placement, and atherectomy with four different devices. Chi-square analysis and Fisher's exact test were used to assess significance. Patency rates were calculated using Kaplan-Meier analysis and compared using log-rank analysis. There were 2137 lesions treated in 1029 patients. The embolization rate was 1.6% (34 events). Jetstream (Pathway, Kirkland, Wash) and DiamondBack 360 (Cardiovascular Systems Inc, St Paul Minn) devices had a combined embolization rate of 22% (8 of 36), 4 of 18 (22%) in each group, which was significantly higher than with PTA alone (5 of 570, 0.9%), PTA and stent (5 of 740, 0.7%), SilverHawk (ev3, Plymouth, Minn) atherectomy (14 of 736, 1.9%), and laser atherectomy (2 of 55, 3.6%; P < .001). There was a significantly higher rate of embolization for in-stent restenosis (6 of 188, 3.2%) and chronic total occlusions (15 of 615, 2.4%) compared with stenotic lesions (13 of 1334, 0.9%; P = .01). The embolization rate was significantly higher in Transatlantic Inter-Society Consensus (TASC) II C and D lesions compared with TASC A and B lesions (P = .018). DE rates were not affected by preoperative runoff status (P = .152). Patency was restored at the completion of the procedure in 32 of 34 cases of DE. The 24-month primary patency, assisted primary patency, and secondary patency in the DE group was 54.0% ± 11.9%, 70.0% ± 10.3%, and 73.2% ± 10.3%, respectively, and was 44.4% ± 1.7%, 61.5% ± 1.7%, and 68.2% ± 1.6%, respectively, when embolization did not occur (P > .05). Limb salvage was 72.6% ± 3.1% in lesions in which no DE occurred vs 83.3% ± 15.2% in lesions in which DE occurred (P = .699). DE is a rare event that occurs more often with the Jetstream and DiamondBack 360 devices. In-stent and complex native lesions are at higher risk for DE. DE is typically reversible with endovascular techniques and has no effect on patency rates and limb salvage.

Thresholds of gully erosion in the coastal plains sands of southeastern Nigeria

The concept of geomorphic threshold as applied in gully erosion studies assumes that water erosion occurs when the combined power of the rainfall energy and overland flow exceeds the resistance of surface materials to detachment and entrainment. This line of reasoning presupposes that certain environmental factors that affect runoff generation and erodibility status of soil can be used in estimating thresholds for gully initiation and sustenance. The entire 413. Km2 Ikpa River basin was covered with grids 1km2 and random number table was used to select 15% of the target population in the basin. The pair-wise correlation technique was employed to establish the threshold values of vegetation cover, organic matter content, relief, slope gradient, litter cover and bulk density for gully incision and development in the fifth order drainage basin underlain by Coastal Plains Sands in eastern Nigeria. The results of the analyses indicate that the threshold value of vegetation cover was 72.5%, while the thresholds value of depth of litter cover was 3.2cm. Other threshold values for gully initiation in the catchment area were 1 degree for slope gradient; 2.70% for organic matter; and 10metres a.s.l for relief. These threshold values were exceeded in almost all the sampled gully sites. The results of the research have implications for cropping in the study area. The convectional rain-storms that is associated with the beginning of the planting season in April/May cannot be controlled by man. Its effects can be reduced to desirable level by increasing the surface contact cover. Mulching, intercropping and the planting of cover crops can ensure adequate vegetation cover of >72.5% on valley –side slopes. Also, crop residue, dry stalks and stovers should be used to encourage the build-up of organic matter above the critical level of 2.70% during the planting season. KEYWORDS: Gully erosion, threshold, Ikpa river, coastal plains, morphometry, intrinsic factors

Superior limb salvage with endovascular therapy in octogenarians with critical limb ischemia

The goal of this study is to compare our results following open and endovascular infrainguinal revascularizations in patients >or=80 and <80 years old presenting with critical limb ischemia (CLI) and to determine if limb salvage (LS) attempt is justified in patients >or=80 with CLI, especially following endovascular interventions. A retrospective analysis of 344 consecutive patients (399 limbs) who presented with CLI and underwent infrainguinal open or endovascular (EV) revascularizations between June 2001 and December 2007 was performed. Patients >or=80 (89 patients, 101 limbs) and <80 years old (255 patients, 298 limbs) were compared for demographics, characteristics, patency, limb salvage, sustained clinical success (preservation of limb, freedom from target extremity revascularization (TER), and resolution of symptoms), secondary clinical success (preservation of limb and resolution of symptoms), overall improvement (preservation of limb, improvement of symptoms), and survival. Patients >or=80 were more likely to be nonambulatory and have coronary artery disease, whereas those <80 were more likely to have hypertension, hyperlipidemia, dialysis-dependence, active tobacco abuse, and taking beta-blockers. Primary amputation rates were similar between two groups (<80 vs >or=80, 6.7% vs 8.1%, P = .530). Perioperative mortality was significantly worse in >or=80 group in the open-treated group (16.2% vs 2.9%, P = .009), whereas it was similar in EV-treated patients (3.1% vs 0.6%, P = .197). The patency rates were similar between groups, however, LS was significantly better in >or=80 EV-treated patients than <80 group, whereas it was similar between groups in open-treated patients. Sustained clinical success, secondary clinical success, and overall improvement rates were similar between age groups. Endovascular-treated patients in >or=80 had significantly better overall improvement than those who were treated by open revascularization (24-month overall improvement 83% +/- 5% vs 61% +/- 9%, P = .043). Multivariate analysis showed diabetes, infrapopliteal intervention, presence of gangrene, nonambulatory status, dialysis-dependence, and runoff status being associated with limb loss whereas age being >/= or <80 was not. Age, coronary artery disease, chronic obstructive pulmonary disease, nonambulatory status, and dialysis-dependence were found to be independently associated with decreased survival. Our results suggest that revascularization in patients >/=80 with CLI is justified, especially when an endovascular intervention can be accomplished. Although limb salvage following endovascular interventions were better in the >/=80 group, sustained clinical success, and secondary clinical success rates were similar following open and endovascular interventions in both age groups. Open procedures carry a high perioperative mortality in the >/=80 age group and should be avoided if possible.

Endovascular treatment of femoropopliteal steno-obstructive disease with percutaneous transluminal angioplasty: midterm results

This study aimed to evaluate midterm outcomes of conventional percutaneous transluminal angioplasty (PTA) in the treatment of femoropopliteal steno-obstructive disease and assess the effect of risk factors on patency rates. One hundred consecutive patients with femoropopliteal steno-obstructive disease underwent PTA, for a total of 104 procedures. Presence of cardiovascular risk factors, TransAtlantic Inter-Society Consensus (TASC) classification, runoff status, pre-and postprocedural clinical data and procedure outcome were recorded. Follow-up consisted of clinical assessment and colour Doppler ultrasonography at 1, 6 and 12 months. Technical success was 96% (96/100). Seven lesions required stent placement. Primary and secondary patency rates were 82.7% and 88.8% at 6 months and 74.3% and 81.5% at 12 months, respectively. Primary patency rates at 12 months were significantly higher for TASC A-B-C lesions than for TASC D lesions (p < 0.05). Primary patency rates at 12 months were 61.6% and 78.8% (p<0.05) for poor or adequate runoff status, respectively. Conventional PTA is a minimally invasive alternative to bypass surgery for treating TASC A-C atherosclerotic lesions in the presence of adequate runoff.

Percutaneous Viabahn-assisted Subintimal Recanalization for Severe Superficial Femoral Artery Occlusive Disease

To evaluate Viabahn-assisted subintimal recanalization (VASIR) in long recanalizations of the superficial femoral artery (SFA). Twenty-eight patients (15 men, 13 women; mean age, 70.6 years +/- 11.2) were studied. Comorbidities were hypertension (n = 24), coronary disease (n = 16), and diabetes (n = 11). Presenting symptoms were disabling claudication (n = 14), rest pain (n = 6), and tissue loss (n = 8). Lesions were angiographically severe (TransAtlantic Intersociety Consensus [TASC] class D, n = 18; TASC class C, n = 8; TASC class B, n = 2); four of the 28 patients had no continuous run-off vessels. The SFA was recanalized percutaneously with standard subintimal techniques and then repaved with Viabahn stent-grafts. The ankle-brachial index (ABI) was obtained and duplex imaging performed at 1 month and then every 3 months. Technical success was achieved in all 28 patients without complications. The mean ABI of 0.47 +/- 0.18 before the procedure increased to 0.88 +/- 0.20 after the procedure. Seventeen of the 28 patients developed palpable foot pulses. The mean follow-up was 8.2 months +/- 3.6 (range, 1-13 months). Twelve recanalizations failed 1 day to 8 months after the procedure. Four patients underwent successful salvage, five underwent bypass, two chose no further therapy, and one required amputation. Thus, life-table primary patency is only 44% +/- 16 but secondary patency is 57% +/- 17. There was no correlation between failure and symptoms, lesion severity, or run-off status, but in eight of 12 failures, in which stents went from the adductor canal to just short of the SFA origin, stenosis occurred at the ends of the stent-grafts, which suggests that deformational forces from knee flexion may play an important role. VASIR shows considerable promise as a primary treatment for SFA occlusions, with diligent follow-up and aggressive repeat intervention. When failure mechanisms are better understood, VASIR may be considered as a substitute for vein bypass in suitable patients.