A new method for IVUS-based coronary artery disease risk stratification: A link between coronary & carotid ultrasound plaque burdens

Interventional cardiologists have a deep interest in risk stratification prior to stenting and percutaneous coronary intervention (PCI) procedures. Intravascular ultrasound (IVUS) is most commonly adapted for screening, but current tools lack the ability for risk stratification based on grayscale plaque morphology. Our hypothesis is based on the genetic makeup of the atherosclerosis disease, that there is evidence of a link between coronary atherosclerosis disease and carotid plaque built up. This novel idea is explored in this study for coronary risk assessment and its classification of patients between high risk and low risk. This paper presents a strategy for coronary risk assessment by combining the IVUS grayscale plaque morphology and carotid B-mode ultrasound carotid intima-media thickness (cIMT) - a marker of subclinical atherosclerosis. Support vector machine (SVM) learning paradigm is adapted for risk stratification, where both the learning and testing phases use tissue characteristics derived from six feature combinational spaces, which are then used by the SVM classifier with five different kernels sets. These six feature combinational spaces are designed using 56 novel feature sets. K-fold cross validation protocol with 10 trials per fold is used for optimization of best SVM-kernel and best feature combination set. IRB approved coronary IVUS and carotid B-mode ultrasound were jointly collected on 15 patients (2 days apart) via: (a) 40MHz catheter utilizing iMap (Boston Scientific, Marlborough, MA, USA) with 2865 frames per patient (42,975 frames) and (b) linear probe B-mode carotid ultrasound (Toshiba scanner, Japan). Using the above protocol, the system shows the classification accuracy of 94.95% and AUC of 0.95 using optimized feature combination. This is the first system of its kind for risk stratification as a screening tool to prevent excessive cost burden and better patients' cardiovascular disease management, while validating our two hypotheses.

Reliable and Accurate Calcium Volume Measurement in Coronary Artery Using Intravascular Ultrasound Videos

Quantitative assessment of calcified atherosclerotic volume within the coronary artery wall is vital for cardiac interventional procedures. The goal of this study is to automatically measure the calcium volume, given the borders of coronary vessel wall for all the frames of the intravascular ultrasound (IVUS) video. Three soft computing fuzzy classification techniques were adapted namely Fuzzy c-Means (FCM), K-means, and Hidden Markov Random Field (HMRF) for automated segmentation of calcium regions and volume computation. These methods were benchmarked against previously developed threshold-based method. IVUS image data sets (around 30,600 IVUS frames) from 15 patients were collected using 40 MHz IVUS catheter (Atlantis® SR Pro, Boston Scientific®, pullback speed of 0.5 mm/s). Calcium mean volume for FCM, K-means, HMRF and threshold-based method were 37.84 ± 17.38 mm(3), 27.79 ± 10.94 mm(3), 46.44 ± 19.13 mm(3) and 35.92 ± 16.44 mm(3) respectively. Cross-correlation, Jaccard Index and Dice Similarity were highest between FCM and threshold-based method: 0.99, 0.92 ± 0.02 and 0.95 + 0.02 respectively. Student's t-test, z-test and Wilcoxon-test are also performed to demonstrate consistency, reliability and accuracy of the results. Given the vessel wall region, the system reliably and automatically measures the calcium volume in IVUS videos. Further, we validated our system against a trained expert using scoring: K-means showed the best performance with an accuracy of 92.80%. Out procedure and protocol is along the line with method previously published clinically.

Laser Atherectomy for Treatment of Femoropopliteal In-Stent Restenosis

Purpose: To investigate if laser atherectomy with adjunctive balloon angioplasty can improve endovascular treatment outcomes for femoropopliteal in-stent restenosis (ISR). Methods: A dual center study included 135 symptomatic patients (mean age 71 years; 76 men) who underwent endovascular treatment of femoropopliteal ISR between 2006 and 2013. Of these, 54 (40%) were treated with laser atherectomy and the remaining 81 patients with balloon angioplasty alone. Angiographic images were reviewed for lesion morphology and characteristics, TransAtlantic InterSociety Consensus (TASC) II classification, and distal runoff. Class I ISR was defined as focal lesions ≤50 mm, class II ISR as lesions >50 mm, and class III ISR as stent total occlusion. Recurrent ISR was determined by a peak systolic velocity ratio >2.4 by duplex ultrasound. Results: Patients treated with laser atherectomy had longer mean ISR lesion length (222 vs 114 mm, p<0.001) and more class III ISR (69% vs 20%, p=0.001). There was no association between laser atherectomy and rates of recurrent restenosis or occlusion for patients with class I/II ISR, but there was a significantly lower rate of target lesion revascularization at 2 years among patients treated with laser atherectomy (14% vs 44%, p=0.05). In comparison, patients with class III ISR treated with laser atherectomy had lower rates of recurrent restenosis at 1 year (54% vs 91%, p=0.05) and 2 years (69% vs 100%, p=0.05). Patients with class III ISR treated with laser atherectomy also had lower rates of recurrent in-stent occlusion at 2-year follow-up (33% vs 71%, p=0.04). Conclusion: When used to treat complex ISR, including in-stent occlusions, laser atherectomy with adjunctive balloon angioplasty may be associated with improved patency.

Automated calcium burden measurement in internal carotid artery plaque with CT: a hierarchical adaptive approach

AIM

Calcium burden measurement in internal carotid artery (ICA) plaque could play an important role in assessing stroke risk and stenosis quantification in the ICA. We propose an automatic method for labelling calcified plaques in ICA in CT images.

METHODS

Our approach builds upon the mean shift paradigm via an adaptive thresholding strategy. The data consists of single CT slices from 75 patients, with variety of plaque sizes and number of calcium regions. The manual measurements were carried out by a neuroradiologist for benchmarking. The calcium burden was measured as the area of the labelled plaque. Various metrics were employed to compare manual and automated measurements including correlation coefficient (CC), dice similarity (DS), Jacard Index (JI), polyline distance metric (PDM) and precision of merit (PoM).

RESULTS

We found that our automated method of calcium area characterization performed accurately compared to manual measurements with CC=0.978, and PoM=0.915. The PDM, DS, and JI, also indicate a good performance with a mean DS=0.85 (SD=0.085), a mean JI=0.747 (SD=0.12), and a mean PDM=0.195 (SD=0.177).

CONCLUSION

The proposed approach for calcium burden measurement, yields reasonably accurate labelling of calcified plaque when benchmarked against manual measurements. The approach is independent of the number and size of calcium regions, and the prototype design shows encouraging results to be adaptable to clinical practice.

Improved correlation between carotid and coronary atherosclerosis SYNTAX score using automated ultrasound carotid bulb plaque IMT measurement

Described here is a detailed novel pilot study on whether the SYNTAX (Synergy between percutaneous coronary intervention with TAXUS and cardiac surgery) score, a measure of coronary artery disease complexity, could be better predicted with carotid intima-media thickness (cIMT) measures using automated IMT all along the common carotid and bulb plaque compared with manual IMT determined by sonographers. Three hundred seventy consecutive patients who underwent carotid ultrasound and coronary angiography were analyzed. SYNTAX score was determined from coronary angiograms by two experienced interventional cardiologists. Unlike most methods of cIMT measurement commonly used by sonographers, our method involves a computerized automated cIMT measurement all along the carotid artery that includes the bulb region and the region proximal to the bulb (under the class of AtheroEdge systems from AtheroPoint, Roseville, CA, USA). In this study, the correlation between automated cIMT that includes bulb plaque and SYNTAX score was found to be 0.467 (p < 0.0001), compared with 0.391 (p < 0.0001) for the correlation between the sonographer's IMT reading and SYNTAX score. The correlation between the automated cIMT and the sonographer's IMT was 0.882. When compared against the radiologist's manual tracings, automated cIMT system performance had a lumen-intima error of 0.007818 ± 0.0071 mm, media-adventitia error of 0.0179 ± 0.0125 mm and automated cIMT error of 0.0099 ± 0.00988 mm. The precision of automated cIMT against the manual radiologist's reading was 98.86%. This current automated algorithm revealed a significantly stronger correlation between cIMT and coronary SYNTAX score as compared with the sonographer's cIMT measurements with multiple cardiovascular risk factors. We benchmarked our correlation between the automated cIMT that includes bulb plaque and SYNTAX score against a previously published (Ikeda et al. 2013) AtheroEdgeLink (AtheroPoint) correlation between the automated cIMT that does not include bulb plaque and SYNTAX score and had an improvement of 44.58%. By sampling cIMT in the bulb region, the automated cIMT technique improves the degree of correlation between coronary artery disease lesion complexity and carotid atherosclerosis characteristics.

Angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use is associated with reduced major adverse cardiovascular events among patients with critical limb ischemia

Angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) are recommended for secondary prevention in peripheral artery disease, but their effectiveness in patients with critical limb ischemia (CLI) is uncertain. We reviewed 464 patients with CLI who underwent diagnostic angiography or endovascular intervention from 2006–2013 at a multidisciplinary vascular center. ACEI or ARB use was assessed at the time of angiography. Major adverse cardiovascular events (MACE), mortality, and major adverse limb events (MALE) were assessed during three-year follow-up. Propensity weighting was used to adjust for baseline differences between patients taking and not taking ACEIs or ARBs. ACEIs or ARBs were prescribed to 269 (58%) patients. Patients prescribed ACEIs or ARBs had more baseline comorbidities including diabetes and hypertension ( p<0.05). Patients prescribed ACEIs or ARBs had lower three-year unadjusted rates of MACE (40% versus 47%) and mortality (33% versus 43%). After propensity weighting, ACEI or ARB use was associated with significantly lower rates of MACE (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.58–0.99, p=0.04) and overall mortality (HR 0.71, 95% CI 0.53–0.95, p=0.02). There was no significant association between ACEI or ARB use and MALE (HR 0.97, 95% CI 0.69–1.35, p=0.2) or major amputation (HR 0.74, 95% CI 0.47–1.18, p=0.1). ACEI/ARB use is associated with lower MACE and mortality in patients with CLI, but there was no effect on limb-related outcomes.

Adherence to guideline-recommended therapies among patients with diverse manifestations of vascular disease

Background

Current guidelines recommend aspirin, statins, angiotensin-converting enzyme inhibitors (ACEIs), and smoking abstinence for all patients with vascular disease. There is little data on the variation in adherence to guideline-recommended therapies among patients with different clinical manifestations of vascular disease.

Purpose

To analyze the variation in adherence to guideline-recommended therapies among patients with diverse manifestations of vascular disease.

Methods

We analyzed a comprehensive database of all patients with critical limb ischemia, claudication, acute limb ischemia, carotid artery stenosis, subclavian artery stenosis, renal artery stenosis, or mesenteric ischemia who underwent angiography between 2006 and 2013 at a multidisciplinary vascular center.

Results

Among 1,114 patients with vascular disease, adherence to guideline-recommended therapy at time of angiography included use of aspirin in 936 (84%), statins in 753 (68%), ACEIs in 673 (60%), and smoking abstinence in 788 (71%). A total of 335 (30%) patients utilized all four guideline-recommended therapies. Adherence to four guideline-recommended therapies was lowest among patients with acute limb ischemia (14%) and highest among patients with renal artery stenosis (37%). Among all patients with vascular disease, the range of adherence to individual guidelines was 64%–91% for aspirin, 43%–83% for statins, 49%–66% for ACEIs, and 47%–78% for smoking abstention.

Conclusion

The majority of patients with diverse manifestations of vascular disease take aspirin and abstain from smoking while fewer patients are prescribed ACEIs and statins. Among the current recommendations, statins have the widest variation in adherence. Less than one-third of patients with diverse manifestations of vascular disease are prescribed all four guideline-recommended therapies.

A comparative approach of four different image registration techniques for quantitative assessment of coronary artery calcium lesions using intravascular ultrasound

In IVUS imaging, constant linear velocity and a constant angular velocity of 1800 rev/min causes displacement of the calcium in subsequent image frames. To overcome this error in intravascular ultrasound video, IVUS image frames must be registered prior to the lesion quantification. This paper presents a comprehensive comparison of four registration methods, namely: Rigid, Affine, B-Splines and Demons on five set of calcium lesion quantification parameters namely: (i) the mean lesion area, (ii) mean lesion arc, (iii) mean lesion span, (iv) mean lesion length, and (v) mean lesion distance from catheter. Using our IRB approved data of 100 patient volumes, our results shows that all four registrations showed a decrease in five calcium lesion parameters as follows: for Rigid registration, the values were: 4.92%, 5.84%, 5.89%, 5.27%, and 4.57%, respectively, for Affine registration the values were: 6.06%, 6.51%, 7.28%, 6.50%, and 5.94%, respectively, for B-Splines registration the values were: 7.35%, 8.03%, 9.54%, 8.18%, and 7.62%, respectively, and for Demons registration the five parameters were 7.32%, 8.02%, 10.11%, 7.94%, and 8.92% respectively. The relative overlap of identified lesions decreased by 5.91% in case of Rigid registration, 6.23% in case of Affine registration, 4.48% for Demons registration, whereas it increased by 3.05% in case of B-Splines registration. Rigid and Affine transformation-based registration took only 0.1936 and 0.2893 s per frame, respectively. Demons and B-Splines framework took only 0.5705 and 0.9405 s per frame, respectively, which were significantly slower than Rigid and Affine transformation based image registration.

Clinical trials in peripheral vascular disease: pipeline and trial designs: an evaluation of the ClinicalTrials.gov database

BACKGROUND

Tremendous advances have occurred in therapies for peripheral vascular disease (PVD); until recently, however, it has not been possible to examine the entire clinical trial portfolio of studies for the treatment of PVD (both arterial and venous disease).

METHODS AND RESULTS

We examined interventional trials registered in ClinicalTrials.gov from October 2007 through September 2010 (n=40,970) and identified 676 (1.7%) PVD trials (n=493 arterial only, n=170 venous only, n=13 both arterial and venous). Most arterial studies investigated lower-extremity peripheral artery disease and acute stroke (35% and 24%, respectively), whereas most venous studies examined deep vein thrombosis/pulmonary embolus prevention (42%) or venous ulceration (25%). A placebo-controlled trial design was used in 27% of the PVD trials, and 4% of the PVD trials excluded patients >65 years of age. Enrollment in at least 1 US site decreased from 51% of trials in 2007 to 41% in 2010. Compared with noncardiology disciplines, PVD trials were more likely to be double-blinded, to investigate the use of devices and procedures, and to have industry sponsorship and assumed funding source, and they were less likely to investigate drug and behavioral therapies. Geographic access to PVD clinical trials within the United States is limited to primarily large metropolitan areas.

CONCLUSIONS

PVD studies represent a small group of trials registered in ClinicalTrials.gov, despite the high prevalence of vascular disease in the general population. This low number, compounded by the decreasing number of PVD trials in the United States, is concerning and may limit the ability to inform current clinical practice of patients with PVD.

Endovascular therapy is effective treatment for focal stenoses in failing infrapopliteal vein grafts

BACKGROUND

To evaluate the efficacy of endovascular therapy for maintaining patency and preserving limbs among patients with failing infrapopliteal bypass grafts.

METHODS

We gathered data from a registry of catheter-based procedures for peripheral artery disease. Of 1554 arteriograms performed from 2006 to 2012, 30 patients had interventions for failing bypass vein grafts to infrapopliteal target vessels. The first intervention for each patient was used in this analysis. Duplex ultrasonography was used within 30 days after intervention and subsequently at 3- to 6-month intervals for graft surveillance.

RESULTS

Interventions were performed for duplex ultrasonography surveillance findings in 21 patients and for symptoms of persistent or recurrent critical limb ischemia in 9 patients. Procedural techniques included cutting balloon angioplasty (83%), conventional balloon angioplasty (7%), and stent placement (10%). Procedural success was achieved in all cases. There were no procedure-related complications, amputations, or deaths within 30 days. By Kaplan-Meier analysis, 37% of the patients were free from graft restenosis at 12 months and 31% were at 24 months. Receiver-operating characteristic analysis indicated that a lesion length of 1.75 cm best predicted freedom from restenosis (C statistic: 0.74). Residual stenosis (P = 0.03), patency without reintervention (P = 0.01), and assisted patency with secondary intervention (P = 0.02) rates were superior for short lesions compared with long lesions. The cohort had acceptable rates of adverse clinical outcomes, with 96% of patients free from amputation at both 12 and 24 months; clinical outcomes were also better in patients with short lesions.

CONCLUSIONS

In this single-center experience with endovascular therapies to treat failing infrapopliteal bypass grafts, rates of limb preservation were high, but the majority of patients developed graft restenosis within 12 months. Grafts with longer stenoses fared poorly by comparison. These data suggest that endovascular interventions to restore or prolong graft patency may be associated with maintained graft patency and that close follow-up with vascular laboratory surveillance is essential.

Association of elevated fasting glucose with lower patency and increased major adverse limb events among patients with diabetes undergoing infrapopliteal balloon angioplasty

Diabetes mellitus (DM) is a significant risk factor for loss of patency after endovascular intervention, but the contribution of glycemic control to infrapopliteal artery patency among patients with DM is unknown. All percutaneous infrapopliteal interventions among patients with DM from 2006 to 2013 were reviewed and pre-procedure fasting blood glucose (FBG) was recorded. The primary endpoint was primary patency at 1 year as determined by duplex ultrasound. A total of 309 infrapopliteal lesions in 149 patients with DM were treated with balloon angioplasty during the study period. The median FBG was 144 mg/dL. At 1 year, the rate of primary patency was 16% for patients with FBG above the median, compared to 46% for patients with FBG below the median (hazard ratio (HR) 1.82 for FBG ≥144, p=0.005). Amputation rates at 1 year trended higher among patients with high versus low FBG (24% vs 15%, p=0.1). One year major adverse limb event rates were also higher for patients with high versus low FBG (35% vs 23%, p=0.05). Although patients with high FBG were more likely to have insulin-requiring DM (73% vs 50%, p=0.003) the association of high FBG with loss of primary patency remained significant even after adjusting for insulin use as well as other lesion-specific characteristics (adjusted HR 1.8, 95% CI 1.2-2.8). In conclusion, high fasting blood glucose at the time of infrapopliteal balloon angioplasty is associated with significantly decreased primary patency and may also be a risk factor for major adverse limb events among patients with a threatened limb.

Femoropopliteal in-stent restenosis: current treatment strategies

Nitinol self-expanding stents are increasingly used to treat symptomatic peripheral arterial disease. Despite reduction in procedural complications and rates of stent fracture, femoropopliteal in-stent restenosis (FP-ISR) remains a common and important clinical problem. Due to heterogenous patient and angiographic characteristics, treatment of FP-ISR continues to evolve. Multiple modalities have been evaluated including standard balloon angioplasty, cutting or scoring balloon angioplasty, repeat stenting (nitinol stent vs. stent-graft vs. drug eluting stent), excisional or laser atherectomy, drug coated balloon angioplasty, and atherectomy followed by drug coated balloon angioplasty. This review highlights the clinical evidence for the currently available modalities in the treatment of FP-ISR. Future studies should utilize uniform classification schemes and assess similar outcomes to help determine the optimal approach for endovascular treatment of FP-ISR.

Adherence to guideline-recommended therapy is associated with decreased major adverse cardiovascular events and major adverse limb events among patients with peripheral arterial disease

BACKGROUND

Current guidelines recommend that patients with peripheral arterial disease (PAD) cease smoking and be treated with aspirin, statin medications, and angiotensin-converting enzyme (ACE) inhibitors. The combined effects of multiple guideline-recommended therapies in patients with symptomatic PAD have not been well characterized.

METHODS AND RESULTS

We analyzed a comprehensive database of all patients with claudication or critical limb ischemia (CLI) who underwent diagnostic or interventional lower-extremity angiography between June 1, 2006 and May 1, 2013 at a multidisciplinary vascular center. Baseline demographics, clinical data, and long-term outcomes were obtained. Inverse probability of treatment propensity weighting was used to determine the 3-year risk of major adverse cardiovascular or cerebrovascular events (MACE; myocardial infarction, stroke, or death) and major adverse limb events (MALE; major amputation, thrombolysis, or surgical bypass). Among 739 patients with PAD, 325 (44%) had claudication and 414 (56%) had CLI. Guideline-recommended therapies at baseline included use of aspirin in 651 (88%), statin medications in 496 (67%), ACE inhibitors in 445 (60%), and smoking abstention in 528 (71%) patients. A total of 237 (32%) patients met all four guideline-recommended therapies. After adjustment for baseline covariates, patients adhering to all four guideline-recommended therapies had decreased MACE (hazard ratio [HR], 0.64; 95% CI, 0.45 to 0.89; P=0.009), MALE (HR, 0.55; 95% CI, 0.37 to 0.83; P=0.005), and mortality (HR, 0.56; 95% CI, 0.38 to 0.82; P=0.003), compared to patients receiving less than four of the recommended therapies.

CONCLUSIONS

In patients with claudication or CLI, combination treatment with four guideline-recommended therapies is associated with significant reductions in MACE, MALE, and mortality.

Association between statin medications and mortality, major adverse cardiovascular event, and amputation-free survival in patients with critical limb ischemia

OBJECTIVES

The aim of this study was to determine the associations between statin use and major adverse cardiovascular and cerebrovascular events (MACCE) and amputation-free survival in critical limb ischemia (CLI) patients.

BACKGROUND

CLI is an advanced form of peripheral arterial disease associated with nonhealing arterial ulcers and high rates of MACCE and major amputation. Although statin medications are recommended for secondary prevention in peripheral arterial disease, their effectiveness in CLI is uncertain.

METHODS

We reviewed 380 CLI patients who underwent diagnostic angiography or therapeutic endovascular intervention from 2006 through 2012. Propensity scores and inverse probability of treatment weighting were used to adjust for baseline differences between patients taking and not taking statins.

RESULTS

Statins were prescribed for 246 (65%) patients. The mean serum low-density lipoprotein (LDL) level was lower in patients prescribed statins (75 ± 28 mg/dl vs. 96 ± 40 mg/dl, p < 0.001). Patients prescribed statins had more baseline comorbidities including diabetes, coronary artery disease, and hypertension, as well as more extensive lower extremity disease (all p values <0.05). After propensity weighting, statin therapy was associated with lower 1-year rates of MACCE (stroke, myocardial infarction, or death; hazard ratio [HR]: 0.53; 95% confidence interval [CI]: 0.28 to 0.99), mortality (HR: 0.49, 95% CI: 0.24 to 0.97), and major amputation or death (HR: 0.53, 95% CI: 0.35 to 0.98). Statin use was also associated with improved lesion patency among patients undergoing infrapopliteal angioplasty. Patients with LDL levels >130 mg/dl had increased HRs of MACCE and mortality compared with patients with lower levels of LDL.

CONCLUSIONS

Statins are associated with lower rates of mortality and MACCE and increased amputation-free survival in CLI patients.

Endovascular recanalization of infrapopliteal occlusions in patients with critical limb ischemia

BACKGROUND

Endovascular therapies are increasingly used for treatment of critical limb ischemia (CLI). Infrapopliteal (IP) occlusions are common in CLI, and successful limb salvage may require restoration of arterial flow in the distribution of a chronically occluded vessel. We sought to describe the procedural characteristics and outcomes of patients with IP occlusions who underwent endovascular intervention for treatment of CLI.

METHODS

All patients with IP interventions for treatment of CLI from 2006 to 2012 were included. Angiographic and procedural data were compared between patients who underwent intervention for IP occlusions vs IP stenosis. Restenosis was determined by Doppler ultrasound imaging. Limb salvage was the primary end point of the study. Additional end points included primary patency, primary assisted patency, secondary patency, occlusion crossing success, procedural success, and amputation-free survival.

RESULTS

A total of 187 patients with CLI underwent interventions for 356 IP lesions, and 77 patients (41%) had interventions for an IP occlusion. Patients with an intervention for IP occlusion were more likely to have zero to one vessel runoff (83% vs 56%; P < .001) compared with interventions for stenosis. Compared with IP stenoses, IP occlusions were longer (118 ± 86 vs 73 ± 67 mm; P < .001) and had a smaller vessel diameter (2.5 ± 0.8 vs 2.7 ± 0.5 mm; P = .02). Wire crossing was achieved in 83% of IP occlusions, and the overall procedural success for IP occlusions was 79%. The overall 1-year limb salvage rate was 84%. Limb salvage was highest in the stenosis group, slightly lower in the successful occlusion group, and lowest in the failed occlusion group (92% vs 75% vs 58%, respectively; P = .02). Unsuccessfully treated IP occlusions were associated with a significantly higher likelihood of major amputation (hazard ratio, 5.79; 95% confidence interval, 1.89-17.7) and major amputation or death (hazard ratio, 2.69; 95% confidence interval, 1.09-6.63).

CONCLUSIONS

Successful endovascular recanalization of IP occlusions can be achieved with guidewire and support catheter techniques in most patients. In patients selected for an endovascular-first approach for IP occlusions in CLI, this strategy can be successfully implemented with favorable rates of limb salvage.

Gender-related variation in the clinical presentation and outcomes of critical limb ischemia

Critical limb ischemia (CLI) is a major cause of limb loss and mortality among patients with advanced peripheral artery disease. Our objective was to evaluate the gender-specific differences in patient characteristics and clinical outcomes among patients with CLI. We performed a retrospective analysis of 97 women and 122 men presenting with CLI who underwent angiography from 2006 to 2010. Baseline demographics, procedural details, and lesion characteristics were assessed for each patient. Kaplan-Meier analysis was used to assess long-term patient and lesion-level outcomes. Cox proportional hazard modeling was used to evaluate the relationship between gender and major adverse cardiovascular events (MACE). Compared to men, women were less likely to have a history of coronary artery disease (39% vs 54%, p = 0.02) or diabetes (57% vs 70%, p = 0.05) but had similar baseline medical therapy. At angiography, women were more likely to have significant femoropopliteal (77% vs 67%, p = 0.02) and multi-level infrainguinal disease (63% vs 51%, p = 0.02). Women were also more likely to undergo multi-vessel percutaneous intervention (69% vs 55%, p = 0.05), but had similar rates of limb salvage after percutaneous intervention or surgical bypass (HR 0.94 [95% CI 0.45-1.94], p = 0.9). During follow-up, women had higher rates of subsequent major adverse cardiovascular events (HR 1.63 [95% CI 1.01-2.63], p = 0.04). In conclusion, women with CLI are more likely to present with femoropopliteal and multi-level infrainguinal disease. Despite similar rates of limb salvage, women with CLI have an increased rate of subsequent major adverse cardiovascular events.

Angiographic characteristics of femoropopliteal in-stent restenosis: association with long-term outcomes after endovascular intervention

OBJECTIVES

The purpose of this study was to identify the relationship between angiographic patterns of restenosis and outcomes after endovascular treatment of femoro-popliteal in-stent restenosis (FP-ISR).

BACKGROUND

ISR is a frequent clinical problem after femoro-popliteal stenting.

METHODS

This was a single center study of all endovascular interventions for FP-ISR from 2006 to 2012. Class I ISR was defined as focal lesions ≤50 mm; Class II ISR as lesions > 50 mm; and Class III ISR as stent chronic total occlusion. Recurrent ISR was defined as peak systolic velocity ratio > 2.4 by duplex ultrasound.

RESULTS

Among 75 cases of FP-ISR, 28 (37%) were Class I, 22 (29%) were Class II, and 25 (33%) were Class III. The mean lesion length was 26 mm for Class I, 135 mm for Class II, and 178 mm for Class III ISR. Patients with Class III ISR more frequently had ISR extending into both the superficial femoral and popliteal artery (48% vs. 18%, P = 0.005). Balloon angioplasty was used most frequently to treat Class I ISR, while adjunctive atherectomy and/or stenting was used for almost all cases of Class III ISR. During 2-year follow-up, rates of repeat restenosis were 39% for Class I, 67% for Class II, and 72% for Class III ISR (P = 0.04). Rates of stent occlusion were 8% for Class I, 11% for Class II, and 52% for Class III ISR (P = 0.009). Class III ISR was associated with significantly increased risk of recurrent ISR (HR 2.4, 95% CI 1.1-5.6) and recurrent occlusion (HR 5.8, 95% CI 1.8-19.0) compared to other types of ISR.

CONCLUSION

Angiographic patterns of FP-ISR are important determinants of subsequent outcomes. Repeat restenosis and occlusion remain common despite currently available technologies.

Mid-term outcomes following endovascular re-intervention for iliac artery in-stent restenosis

OBJECTIVES

We sought to evaluate the procedural characteristics and clinical outcomes of endovascular repair for iliac artery (IA) in-stent restenosis (ISR).

BACKGROUND

An increasing percentage of patients with complex IA occlusive disease are treated with an endovascular approach, but the outcomes of IA-ISR have not been well described.

METHODS

We analyzed all endovascular procedures for treatment of IA-ISR performed at our institution between July 2006-December 2010. The primary outcome was primary patency, defined as <50% stenosis as assessed by clinical examination and duplex ultrasonography (DUS).

RESULTS

Forty-one lesions in 24 patients who underwent repeated endovascular intervention for treatment of IA-ISR. Most lesions were unilateral and involved the common IA (66%). The mean length of ISR was 30.1 ± 14.1 mm with type I (focal) and II (diffuse) ISR occurring with the greatest frequency (34% and 39%, respectively). All patients underwent balloon angioplasty; adjunctive stenting zwas performed in 27 (66%) of the lesions. Type II ISR lesions more frequently required stenting (13/16 lesions, P = 0.02 compared with other patterns of ISR). Procedural success was 100% with a mean gain of 0.13 in the ankle-brachial index (P = 0.001). The 6- and 12-month primary patency rates were 96% and 82%, respectively. The 12-month primary-assisted patency rate was 90% with clinically driven target lesion revascularization (TLR) in three patients.

CONCLUSIONS

Endovascular treatment of IA-ISR using an approach of balloon angioplasty followed by selective stenting is associated with high-patency rates and low rates of TLR at 1 year.

Transradial and transfemoral coronary angiography and interventions: 1-year outcomes after initiating the transradial approach in a cardiology training program

BACKGROUND

Limited data are available regarding the safety and feasibility of initiating transradial (TR) diagnostic coronary angiography (CA) and percutaneous coronary intervention (PCI) in cardiology fellowship programs.

METHODS

From July 2010 to June 2011, University of California, Davis Medical Center, adopted the TR approach with supervised cardiology fellows as the primary operators. Procedural variables and clinical outcomes of TR and transfemoral (TF) procedures were compared. To minimize confounding variables, ST-elevation myocardial infarction, bypass graft interventions, chronic total occlusions, and procedures with concomitant right heart catheterizations were excluded. To reflect the learning curve of the TR approach, this experience was assessed in 2 sequential 6-month periods.

RESULTS

A total of 402 diagnostic CAs and 255 PCIs were included. Transradial access was used in 141 (35%) of the CAs and in 72 (28%) of PCIs. Within the TR-CA and TF-CA (n = 261) groups, there was no difference between fluoroscopy (10.4 ± 6.0 vs 11.0 ± 8.9, P = .63) or procedure (31.8 ± 11.5 vs 33.2 ± 13.8, P = .55) time throughout the academic year with a significant trend toward lower contrast use (128 ± 52 vs 110 vs 50, P = .04) by the second half. In addition, during the second half of the academic year, the TR-CA showed significantly higher fluoroscopy (11.0 ± 8.9 vs 6.7 ± 6.8, P = .001) and procedure (33.2 ± 13.8 vs 27.2 ± 11.6, P = .0015) times when compared with TF-CA. Transfemoral PCI (n = 183) and TR-PCI showed no significant difference between all fluoroscopy and procedure time and contrast use when comparing the 2 halves of the academic year. When comparing TF with TR within each academic half year, there was no difference within the PCI group. Vascular complications were less with the TR approach. Overall procedural success rates were high, and there were low rates of crossover and periprocedural complications in both the TR and the TF groups.

CONCLUSION

A TR approach is safe for CA and PCI when performed by supervised operators in training. Although the learning curve for trainees appears slower for TR-CA compared with TF-CA, cardiology fellowship training programs should be encouraged to adopt TR procedures as part of their curriculum.

Excimer laser with adjunctive balloon angioplasty and heparin-coated self-expanding stent grafts for the treatment of femoropopliteal artery in-stent restenosis: twelve-month results from the SALVAGE study

OBJECTIVES

The aim of the study is to evaluate the safety and effectiveness of treating femoropopliteal in-stent restenosis (ISR) with debulking with excimer laser followed by implantation of a VIABAHN endoprosthesis.

BACKGROUND

The optimal treatment strategy for femoropopliteal ISR is unclear.

METHODS

The SALVAGE study is a multicenter prospective registry involving nine US centers. Patients with femoropopliteal ISR with moderate to severe intermittent claudication or critical limb ischemia (Rutherford categories 2-5) and an ankle-brachial index (ABI) =0.8 were treated with excimer laser and the VIABAHN endoprosthesis. The primary efficacy endpoint is primary patency at 12 months as measured by duplex ultrasonography. The primary safety endpoint is the major adverse event (MAE) rate at 30 days.

RESULTS

Twenty-seven patients were enrolled. The mean lesion length was 20.7 ± 10.3 cm. The majority of lesions were TASC (TASC I) C and D (81.4%). All lesions were pretreated with excimer laser and percutaneous transluminal angioplasty (PTA) prior to VIABAHN implantation. Technical success was achieved in 100% of cases. There were no MAE at 30 days. Primary patency at 12 months was 48%. The ankle brachial index increased from 0.58 ± 0.24 at baseline to 0.90 ± 0.17 at 12 months. There was improvement in all quality-of-life parameters. The 12-month TLR rate was 17.4%.

CONCLUSIONS

The strategy of excimer laser atherectomy and PTA followed by implantation of a self-expanding stent graft for the treatment of femoropopliteal ISR is safe and associated with high procedural success. Primary patency rate at 12-months was suboptimal; however, the TLR rate was low.

Outcomes following treatment of femoropopliteal in-stent restenosis: a single center experience

OBJECTIVES

The aim of this study is to describe a single-center experience with endovascular treatment of femoropopliteal in-stent restenosis (ISR).

BACKGROUND

Femoropopliteal artery stenting is associated with a significant risk of ISR. Data are limited on the optimal treatment strategy and associated outcomes.

METHODS

A single institution retrospective chart review study was performed for patients who underwent endovascular treatment of femoropopliteal ISR from January 2006 to October 2008. Clinical and procedural characteristics, angiographic findings, and 12-month primary and secondary patency rates were analyzed. Univariate analysis was performed to identify predictors of 12-month primary patency.

RESULTS

Twenty-two limbs were treated in 20 patients during the study period. Procedural success was achieved in 21 limbs (95.5%). Laser, balloon angioplasty, and excisional atherectomy were the primary therapy in 52.4%, 33.3%, and 14.3% of the cases, respectively. Adjunctive balloon angioplasty was performed after laser and excisional atherectomy in all cases. The mean length of ISR was 13.2 ± 11.3 cm with a significant proportion of cases (40.9%) having Type IV pattern of ISR. At 12 months, primary and combined primary-assisted and secondary patency rates were 47.6 and 61.9%, respectively. Of the 11 limbs that did not have secondary patency, 6 had mild or no symptoms, and, therefore, repeat intervention was not performed. There was one transmetatarsal amputation during the 12-month follow-up period. In this study, there was no significant predictor of 12-month primary patency.

CONCLUSIONS

Treatment of ISR remains challenging with significant risk of recurrent restenosis. Further research is required to improve long-term patency.

Early duplex scanning after infrainguinal endovascular therapy

OBJECTIVES

Duplex ultrasound scanning (DUS) has benefit for intraoperative and subsequent evaluation of surgical bypasses in the lower extremities. The utility of DUS after endovascular revascularizations is not established. This study was performed to evaluate whether DUS findings after infrainguinal endovascular interventions for critical limb ischemia (CLI) were predictive of need for reintervention or amputation.

METHODS

To identify the study cohort, peripheral interventions for CLI (Rutherford grades 4, 5, 6) over a 24-month period (2006-2007) were reviewed. DUS findings were considered indicative of hemodynamic stenosis if the peak systolic velocity (PSV) was ≥ 180 cm/s or the PSV velocity ratio was ≥ 2.0. Demographic, clinical, procedural, and outcomes were examined. SVS and TASC II classifications and reporting standards were used. Arteriograms were reviewed and treated segments were categorized as patent (<30% residual stenosis) or abnormal (≥ 30% residual stenosis).

RESULTS

There were 122 infrainguinal interventions for CLI in 113 patients (53% male; mean age 71 years). Risk factors included diabetes: 61%; renal failure: 20%; and smoking (within 1 year): 40%. DUS was performed within 30 days of the index procedure in 90 cases. Fifty patients had an abnormal early duplex and 40 patients had a normal duplex. In patients with a normal duplex ultrasound the amputation rate was 5% vs 20% in the group with an abnormal duplex (P = .04). Primary patency was 56% in the normal duplex group and 46% in the abnormal duplex group (P = .18). Early duplex ultrasound was able to identify a residual stenosis not seen on completion angiography in 56% of cases.

CONCLUSIONS

Duplex scanning detects residual stenosis missed with conventional angiography after infrainguinal interventions. An abnormal DUS in the first 30 days after an intervention is associated with an increased risk of amputation. This suggests a possible role for intraprocedural DUS, as well as routine postprocedure DUS, close clinical follow-up, and consideration of reintervention for residual abnormalities in patients treated for CLI.

The role of stent-grafts for prevention and treatment of restenosis

Restenosis rates in the superficial femoral artery remain high in patients treated with balloon angioplasty or bare metal stents. Stent-grafts represent an alternative endovascular treatment modality for these patients. In the US, the only FDA-approved stent-graft for femoral use is the Viabahn endoprosthesis (W.L. Gore, Flagstaff, AZ). The Viabahn is constructed of nitinol and ePTFE and has a proprietary heparin bioactive surface. Stent-grafts have the potential to reduce restenosis by impeding intimal hyperplasia and reducing tissue in-growth; however, the problem of edge restenosis has not been eliminated. Graft thrombosis remains an important mode of stent-graft failure. The Viabahn has been shown in observational studies and randomized trials to be an effective and safe treatment strategy compared to bare self-expanding stents and surgical prosthetic bypass grafts. Patient and appropriate lesion selection remain important in achieving long term patency. In this paper, we review the data surrounding the use of stent-grafts in the SFA to prevent and treat restenosis. Important technical considerations specific to the use of the Viabahn are also discussed.

Nitinol stent implantation versus balloon angioplasty for lesions in the superficial femoral artery and proximal popliteal artery: twelve-month results from the RESILIENT randomized trial

BACKGROUND

Controversy still exists regarding the best endovascular treatment strategy for patients with symptomatic disease of the superficial femoral artery. There are conflicting data regarding the benefits of superficial femoral artery stenting and the role of primary stenting compared with balloon angioplasty with provisional stent implantation.

METHODS AND RESULTS

A total of 206 patients from 24 centers in the United States and Europe with obstructive lesions of the superficial femoral artery and proximal popliteal artery and intermittent claudication were randomized to implantation of nitinol stents or percutaneous transluminal angioplasty. The mean total lesion length was 71 mm for the stent group and 64 mm for the angioplasty group. Acute lesion success (<30%residual stenosis) was superior for the stent group compared with the angioplasty group (95.8% versus 83.9%; P<0.01). Twenty-nine (40.3%) patients in the angioplasty group underwent bailout stenting because of a suboptimal angiographic result or flow-limiting dissection. Bailout stenting was treated as a target lesion revascularization and loss of primary patency in the final analysis. At 12 months, freedom from target lesion revascularization was 87.3% for the stent group compared with 45.1% for the angioplasty group (P<0.0001). Duplex ultrasound-derived primary patency at 12 months was better for the stent group (81.3% versus 36.7%; P<0.0001). Through 12 months, fractures occurred in 3.1% of stents implanted. No stent fractures resulted in loss of patency or target lesion revascularization.

CONCLUSIONS

In this multicenter trial, primary implantation of a self-expanding nitinol stent for moderate-length lesions in the superficial femoral artery and proximal popliteal artery was associated with better acute angiographic results and improved patency compared with balloon angioplasty alone.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00673985.

Carotid Artery Stenting: Update

"Extracranial carotid artery stenosis is responsible for approximately 20-30% of ischemic strokes. Traditionally, carotid artery stenosis has been treated with carotid endarterectomy. However, the low periprocedural complication rate and the mid term durability of carotid artery stenting has made it a competitive alternative treatment strategy. This update reviews the technical aspects of carotid artery stenting, clinical data supporting carotid artery stenting-particularly in high risk patients, and the complications associated with carotid artery stenting."

Excimer laser assisted angioplasty for complex infrainguinal peripheral artery disease: a 2008 update

Conventional percutaneous transluminal angioplasty (PTA) for complex or long segment infrainguinal occlusive arterial disease is limited by elastic recoil, dissection and restenosis, with high rates of intermediate and long term restenosis . Debulking with excimer laser has been advocated as a useful adjunctive strategy to improve procedural success and long term patency. This paper reviews the technological development of excimer laser, the studies supporting its use in infrainguinal arterial disease, effective and safe lasing techniques, its advantages, limitations and disadvantages. Case examples will be presented to illustrate its use in infrainguinal arterial disease. Although randomized controlled trials are lacking, existing registry and case series studies suggest efficacy of the excimer laser-assisted PTA for complex infrainguinal arterial disease, including patients with critical limb ischemia.