Interobserver variability in physician-modified endograft planning by comparison with a three-dimensional printed aortic model.

BACKGROUND: With the increasing application of fenestrated and physician-modified endografting for aneurysm repair, there is increasing concern about the accuracy of vessel position measurements based on computed tomography scans. Inaccuracies in measurements may result in a "window-shutter" or "eclipsing" phenomenon whereby the fenestration may not overlie the vessel ostium completely. We hypothesized that vessel position measurements from reconstructed imaging do not represent the true vessel position as obtained from a three-dimensional (3D) printed physical model of the visceral aortic segment. METHODS: Medical 3D modeling software was used to develop the 3D reconstructions, which were then exported to the 3D printing software. This allowed 3D models to be physically generated. The distances to the top and bottom and the angle of each of the celiac, superior mesenteric, right renal, and left renal arteries were recorded. These same measurements were obtained by each of the blinded reviewers in addition to the aortic diameter at the midpoint of each of these vessels. Measurements were compared with intraclass correlation coefficient, nonparametric Spearman rank correlation test, and one-sample t-test to assess accuracy and precision. Statistical significance was set at P < .05 for all tests. RESULTS: Both the individual measurements and the average of the measurements were statistically accurate (significant) for the bottom of the superior mesenteric artery and the top and bottom of both the right and left renal arteries. There was variability and inaccuracy in all visceral vessel angles and in the bottom of the celiac artery (the top and the angle of the celiac artery were the arbitrary referents). CONCLUSIONS: Whereas the visceral vessel orifices are largely accurately assessed and measured, the vessel angles are not. This may lead to an eclipsing phenomenon, which may contribute to branch or fenestrated vessel failure and therefore reintervention. Further efforts should assess the clinical significance of the eclipsing phenomenon and should target accurate and appropriate fenestration construction to prevent long-term morbidity.

Comparison of interventional outcomes according to preoperative indication: a single center analysis of 2,240 limb revascularizations.

BACKGROUND: Outcomes after lower extremity revascularization are usually reported according to the level of peripheral arterial disease (PAD, aortoiliac or infrainguinal) or the method of treatment (open or endovascular surgery). Outcomes stratified by indication, ie, claudication or critical limb ischemia (rest pain and tissue loss), have not been well studied. The purpose of this study was to compare postoperative outcomes according to the preoperative indications. STUDY DESIGN: Outcomes of 2,240 consecutive limb revascularizations in 1,732 patients from January 1998 through December 2005 were stratified and examined according to preoperative indication: claudication (n=999 limbs), ischemic rest pain (n=464 limbs), or tissue loss (n=777 limbs). End points measured included primary and secondary interventional or operative patency, limb salvage, survival, amputation-free survival, maintenance of ambulation, maintenance of independence, and resolution of presenting symptoms. RESULTS: The proportion of medical comorbidities and the severity of disease increased significantly by cohort from claudication to rest pain to tissue loss. With a mean followup of 1,089 days (range 0 to 3,689 days), overall outcomes performance declined consistently according to indication for all end points measured at 5 years (claudication, rest pain, tissue loss, p value): secondary reconstruction patency (93%, 80%, 66%, respectively; p < 0.001), limb salvage (99%, 81%, 68%, respectively; p < 0.001), survival (78%, 46%, 30%, respectively; p < 0.001), amputation-free survival (78%, 42%, 25%, respectively; p < 0.001), maintenance of ambulation (96%, 78%, 68%, respectively; p < 0.001), maintenance of independence (98%, 85%, 75%, respectively; p < 0.001), and resolution of presenting symptoms (79%, 61%, 42%, respectively; p < 0.001). CONCLUSIONS: There is a declining spectrum of outcomes performance from claudication to rest pain to tissue loss. These findings question the accuracy of all previously published data for critical limb ischemia, for which rest pain and tissue loss are usually blended and reported as a single outcomes value.

Is incidental renal arteriography justified in a population of patients with symptomatic peripheral arterial disease?

Renal artery stenosis is a consequence of generalized atherosclerosis and many specialists perform routine selective renal angiography to detect and treat renal artery stenosis. The incidence of clinically important renal artery stenosis is not well defined in patients with symptomatic peripheral arterial disease. The purpose of this study was to better delineate the incidence of and the risk factors associated with renal artery stenosis, renovascular hypertension, and ischemic nephropathy incidentally discovered during angiography for symptomatic peripheral arterial disease. Two hundred consecutive patients undergoing angiographic evaluation of symptomatic lower extremity peripheral arterial disease were studied retrospectively. Angiograms were reviewed for the presence of renal artery stenosis (defined as >or= 25% diameter reduction in either renal artery) and findings were then correlated to the clinical diagnosis of renovascular hypertension (> 50% renal artery stenosis and >or= 3-drug resistive hypertension) and ischemic nephropathy (defined as > 50% bilateral renal artery stenosis, 3-drug hypertension, and creatinine >or= 1.5). Angiographic findings were also correlated with risk factors to determine if a relationship correlated to the presence of and degree of renal artery stenosis. Data were analyzed using the Student's t test, Chi-square model, and multiple logistic regression analysis. The overall incidence of any degree of renal artery stenosis in this study population was 26% (52 patients). Only 24 (12%) patients had an incidental finding of >or= 50% stenosis in either renal artery. Six (3%) of these patients were found to have associated renovascular hypertension. Additionally, 9 (4.5%) patients had coexistent renal insufficiency and significant renal artery stenosis; five with end-stage renal disease on chronic hemodialysis. Only one patient with end-stage renal disease had poorly controlled 3-drug hypertension. Thus definitive ischemic nephropathy was present in only one (0.5%) patient. Statistically significant risk factors associated with the presence of renal artery stenosis include hypertension (P < .001), coronary disease (P = .024), female gender (P = .010), diabetes (P = .039), aorto-iliac disease (P = .031), multiple levels of peripheral arterial disease (P < .001), and age over 60 ( P < .001). While the incidence of renal artery stenosis in patients being evaluated for symptomatic peripheral arterial disease is similar to that reported in the cardiology literature, the incidence of renovascular hypertension and ischemic nephropathy is exceedingly low (3% and 0.5%, respectively)-findings similar to data reported in the general hypertensive population. These data suggest that incidental selective renal angiography is not justified in patients with symptomatic peripheral arterial disease.

Safety and efficacy of reteplase for the treatment of acute arterial occlusion: complexity of underlying lesion predicts outcome.

We evaluated both the safety and efficacy of reteplase for treatment of acute arterial occlusion as well as outcomes based on treatment of the underlying lesion. From November 2000 to February 2004, reteplase was used to treat arterial occlusions in 81 patients. Catheter-directed intrathrombus thrombolysis was performed with reteplase (0.5 units/hr) continuous infusion. Percutaneous mechanical thrombectomy (Angiojet) was performed in 61% (n = 50) of patients prior to thrombolysis. Unmasking of significant lesions resulted in endovascular intervention (39.5%), open surgical repair (24.6%), or both endovascular and surgical repair (9.8%) of the lesion. No lesion was found in 25.9% of patients. Major and minor complication rates as well as restoration of patency, limb salvage, and amputation-free survival were evaluated. Eighty-one patients received reteplase therapy (median = 10.3 +/- 5.3 units, 19.5 +/- 7.4 hr) followed by next-day arteriogram to assess thrombus removal. Technical success was achieved in 96.2% (n = 78) of cases. Kaplan-Meier life table analysis revealed overall primary patency rates of 76.3%, 60.1%, and 51.6%, at 1, 6, and 12 months, respectively. Overall amputation-free survival rates were 86.4%, 76.4%, and 69.7% at 1, 6, and 12 months, respectively. When subdivided into postlysis intervention, the lysis-only group achieved increased patency (p = 0.0143) and increased limb salvage (p = 0.0219) at 1 year compared to the lysis and endovascular intervention and the lysis and surgical groups. The 30-day complication rate was 17.3% (n = 14), with a major complication rate of 4.9% (n = 4) and a minor complication rate of 12.3% (n = 10). There were no intracranial hemorrhagic complications. Intra-arterial catheter-directed infusion of reteplase for acute lower extremity ischemia is safe and efficacious, as shown by the low risk of bleeding complications, high limb salvage rates, and low mortality rates in this study. The complexity of the lesion that is unmasked through thrombolytic therapy is a predictor of patency and limb salvage.

Does a standardization tool to direct invasive therapy for symptomatic lower extremity peripheral arterial disease improve outcomes?

OBJECTIVES: While decision analysis and treatment algorithms have repeatedly been shown to improve quality of care in many areas of medicine, no such algorithm has emerged for the invasive management of lower extremity peripheral arterial disease. Using the best available evidence-based outcomes data, our group designed a standardization tool, the Lower Extremity Grading System (LEGS) score, which consistently directs limbs to a specific treatment on the basis of presentation. The purpose of this study was to examine whether use of such a tool improves outcomes by directing treatment of lower extremity peripheral arterial disease. METHODS: Over 18 months (July 2001-December 2002) our group intervened in 673 limbs (angioplasty, open surgery, primary limb amputation) with lower extremity peripheral arterial disease. During this time we developed the LEGS score, and implemented its prospective use for the final 362 limbs. For the purpose of this study, all 673 limbs were retrospectively scored with the LEGS score to determine the LEGS recommended best treatment. Of the 673 limbs, 551 (81.9%) received the same treatment as recommended with LEGS and 122 (18.1%) received treatment contrary to LEGS. Limbs treated contrary to LEGS (cases) were then compared with matched control limbs (treated according to LEGS), with similar angiographic findings, clinical presentation, preoperative functional status, comorbid conditions and operative technical factors. Outcomes measured at 6 months included arterial reconstruction patency, limb salvage, survival, and maintenance of ambulatory status and independent living status. Kaplan-Meier curves were used to assess patency, limb salvage, and survival; associated survival curves were compared with the log-rank test. Functional outcomes were compared with the Fisher exact test. RESULTS: After matching case limbs with control limbs, 9 limbs had no control match. Thus 113 limbs in 100 patients treated contrary to LEGS were compared with 113 limbs in 100 patients treated according to LEGS. Limbs treated contrary to LEGS resulted in significantly inferior outcomes at 6 months for measures of primary patency (57.5% vs 84.3%; P < .001), secondary patency (73.2% vs 96.2%; P < .001), limb salvage (89.7% vs 97.2%; P = .04), and maintenance of ambulatory status (78% vs 92%; P = .02). As an additional finding, 29.6% (92 of 311) of interventions performed before implementation of the algorithm were treated contrary to LEGS, and thus contrary to objectively determined best therapy, compared with 8.3% (30 of 362) after LEGS implementation (P < .001). CONCLUSIONS: Limbs treated according to our standardization tool resulted in better outcomes compared with limbs treated contrary to the algorithm. These data suggest that routine use of an appropriately validated treatment standardization algorithm is capable of improving overall results for invasive treatment of lower extremity peripheral arterial disease.