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Dive into the research topics where John Marek is active.

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Featured researches published by John Marek.


Journal of Vascular Surgery | 2003

Technique and results of transfemoral superselective coil embolization of type II lumbar endoleak

Karthikeshwar Kasirajan; Brian Matteson; John Marek; Mark Langsfeld

OBJECTIVE This study was undertaken to describe the technique of transfemoral superselective coil embolization of type II endoleak and its influence on abdominal aortic aneurysm diameter. METHODS Over 23 months, 104 aortic stent grafts were deployed to exclude abdominal aortic aneurysms, at an academic medical center. Increase in aneurysm diameter and perigraft findings on contrast material-enhanced computed tomography scans prompted arteriography. Procedures were performed solely by vascular surgeons in a surgical angiography suite. In 7 patients aneurysm access was via the iliolumbar branches of the internal iliac artery, and in 1 patient aneurysm access was via the inferior mesenteric artery through the arc of Riolan from the superior mesenteric artery. Coaxial catheters were placed to gain access to the aneurysm (8F to 5F to 3F, or 5F to 3F). A 3F Tracker18 was the most distal catheter through which an assortment of 0.018 microcoils were deployed within the aneurysm, and the origin of the feeding vessels when possible. RESULTS Aneurysm diameter increased 0.48 +/- 0.2 cm over 10.8 +/- 5 months before superselective coil embolization. In 6 of 8 patients superselective coil embolization embolization resulted in a mean decrease in aneurysm diameter of 1.3 +/- 1.2 cm over 9 +/- 3.2 months. Failure was presumed due to inability to reach the aneurysm sac in 1 patient and was associated with oral anticoagulation in 1 other patient. CONCLUSION Proper identification of the source of type II endoleak and its complete occlusion, combined with aneurysm sac coiling, may result in prompt decrease in aneurysm size.


Journal of Endovascular Therapy | 2003

Covered Stents for True Subclavian Aneurysms in Patients with Degenerative Connective Tissue Disorders

Karthikeshwar Kasirajan; Brian Matteson; John Marek; Mark Langsfeld

Purpose: To report the endovascular repair of rare true aneurysms of the subclavian artery in patients with degenerative connective tissue disorders. Case Reports: Two patients, one with Marfan syndrome and the other with idiopathic cystic medial necrosis, presented with 3 subclavian artery aneurysms. A Wallgraft and 2 Viabahn covered stents were used to successfully exclude these aneurysms. After 3 months, the Wallgraft thrombosed, but the contralateral Viabahn remained patent at the most recent examination 13 months after treatment. The other patient with the unilateral aneurysm had a patent Viabahn stent-graft at 10 months. Conclusions: Patients with degenerative connective tissue disorders may benefit from less invasive treatment with stent-grafts. The more flexible Viabahn stent-graft may be better able to adapt to arterial tortuosity. However, the long-term results of this new technique have not yet been established.


Journal of Vascular Surgery | 2011

Early and long-term comparison of endovascular treatment of iliac artery occlusions and stenosis

Raffaele Pulli; Walter Dorigo; Aaron Fargion; Alessandro Alessi Innocenti; Giovanni Pratesi; John Marek; Carlo Pratesi

OBJECTIVES This study evaluated early and long-term results of endovascular treatment of iliac artery occlusions and compared these outcomes with those in patients treated for stenotic lesions. METHODS During a 10-year period ending in January 2010, 223 endovascular procedures to treat aortoiliac occlusive disease (PAD) were performed. All patients were prospectively enrolled in a dedicated database. The intervention was performed for iliac occlusion in 109 patients (group 1) and for iliac stenosis in 114 (group 2). Early results were analyzed and compared by χ² and Fisher exact tests. Follow-up consisted of clinical examination and duplex scanning at discharge, ≤ 3 months, at 6 and 12 months, and yearly thereafter. Follow-up results were analyzed with Kaplan-Meier curves and compared with the log-rank test. RESULTS The two groups had similar risk factors for atherosclerosis and comorbidities. Critical limb ischemia was more common in group 1 (20.5%) than in group 2 (8.5%; P = .01). Intraoperative technical details were similar, except for a higher percentage of brachial and contralateral femoral access and more frequent use of nitinol stents in group 1. Two immediate technical failures occurred, one in both groups, requiring immediate conversion to surgical bypass. Four intraoperative iliac ruptures occurred, two in each group; all were successfully treated with covered stents. An additional 10 immediate complications occurred (8 in group 1; 2 in group 2), one of which required conversion to open surgical bypass. The cumulative rate of perioperative complications was 9% in group 1 and 3.5% in group 2 (P = .08). Primary patency at 30 days was 97.3% and 98.7%, respectively. Mean duration of follow-up was 28.4 months; 203 patients (91%) had a regular postoperative follow-up visit. At 60 months, primary patency in group 1 vs group 2 was 82.4% vs 77.7% (P = .9), assisted primary patency was 90.6% vs 85.5% (P = .4), and estimated secondary patency was 93.1% vs 92.8% (P = .3). The cumulative rate of reintervention during follow-up (excluding reinterventions performed in the perioperative period) was 2.5% in group 1 and 12.5% in group 2 at 60 months (P = .09). Univariate analysis in group 1 failed to find any of the examined risk factors significantly affected long-term primary patency rates. CONCLUSIONS In our experience, endovascular treatment of iliac occlusions provides excellent early and long-term results, similar to those obtained in the treatment of stenotic lesions.


American Journal of Surgery | 1998

Evaluating institutional variability of duplex scanning in the detection of carotid artery stenosis

Bryan K Criswell; Mark Langsfeld; Michael J Tullis; John Marek

PURPOSE Duplex scanning is widely used to measure carotid artery stenosis, but the issue of variability between institutions must be raised. To examine for this potential variability, we evaluated two ATL Ultramark 9 duplex machines at two hospitals within our institution. METHODS Stenosis was calculated angiographically as in the North American Symptomatic Carotid Endarterectomy Trial (NASCET). Internal carotid artery (ICA) to common carotid artery (CCA) peak systolic velocity (PSV) ratios were determined using the two ATL machines. Receiver operating characteristic (ROC) curves were generated for each hospital. RESULTS ROC curves varied significantly. The area under the curve from hospital 1 was 0.95 (SE = 0.021); the area under the curve from hospital 2 was 0.87 (SE = 0.034). The curves were essentially statistically different (P = 0.0516). COMMENTS We showed a difference in predicting diameter stenosis utilizing ICA PSV/CCA PSV ratios at two hospitals within our institution. Variability is likely due to technologists, since equipment and physician interpreters were the same. Criteria must be developed for each different machine in each laboratory. Quality assurance is critical to minimize variability.


Surgical Clinics of North America | 1998

INFECTION IN THE ISCHEMIC LOWER EXTREMITY

Donald E. Fry; John Marek; Mark Langsfeld

Infections in the lower extremity of the patient with ischemia can cover a broad spectrum of different diseases. An understanding of the particular pathophysiologic circumstances in the ischemic extremity can be of great value in understanding the natural history of the disease and the potential complications that may occur. Optimizing blood flow to the extremity by using revascularization techniques is important for any patient with an ischemic lower extremity complicated by infection or ulceration. Infections in the ischemic lower extremity require local débridement and systemic antibiotics. For severe infections, such as necrotizing fasciitis or the fetid foot, more extensive local débridement and even amputation may be required. Fundamentals of managing prosthetic graft infection require removing the infected prosthesis, local wound débridement, and systemic antibiotics while attempting to preserve viability of the lower extremity using autogenous graft reconstruction.


Journal of Vascular Surgery | 2011

Early and long-term results of carotid endarterectomy in diabetic patients

Walter Dorigo; Raffaele Pulli; Giovanni Pratesi; Aaron Fargion; John Marek; Alessandro Alessi Innocenti; Carlo Pratesi

PURPOSE To evaluate results of carotid endarterectomy (CEA) in diabetic patients in a large single-center experience. METHODS Over a 13-year period ending in December 2008, 4305 consecutive CEAs in 3573 patients were performed. All patients were prospectively enrolled in a dedicated database. Interventions were performed in diabetic patients in 883 cases (20.5%; group 1) and in nondiabetics in the remaining 3422 (79.5%; group 2). Early results in terms of 30-day stroke and death rates were analyzed and compared. Follow-up results were analyzed with Kaplan-Meier curves and compared with log-rank test. RESULTS Diabetic patients were more likely to be females and to have coronary artery disease, peripheral arterial disease, hyperlipemia, and arterial hypertension than nondiabetics. There were no differences between the two groups in terms of preoperative clinical status or degree of carotid stenosis. Interventions were performed under general anesthesia with somatosensory-evoked potentials (SEPs) monitoring in 67% of the patients in both groups, while the remaining interventions were performed under clinical monitoring. Shunt insertion (14% and 11%, respectively) and patch closure rates (79% and 76%, respectively) were similar between the two groups. There were no differences between the two groups in terms of neurological outcomes, while the mortality rate was higher in group 1 than in group 2 (P = .002; odds ratio [OR], 3.5; 95% confidence interval [CI], 1.5-8.3); combined 30-day stroke and death rate was significantly higher in group 1 (2%) than in group 2 (0.9%; P = .006; 95% CI, 1.2-3.9; OR, 2.2). At univariate analysis, perioperative risk of stroke and death in diabetic patients was significantly higher in patients undergoing intervention with SEP cerebral monitoring (95% CI, 0.9-39.9; OR, 5.9; P = .01), and this was also confirmed by multivariate analysis (95% CI, 1.1-23.1; OR, 8.3; P = .04). The same analysis in nondiabetics demonstrated that again the need for general anesthesia significantly increased perioperative risk, but this was not significant at multivariate analysis. Follow-up was available in 96% of patients, with a mean duration of 40 months (range, 1-166 months). There were no differences between the two groups in terms of estimated 7-year survival (87.3% and 88.8%, respectively; 95% CI, 0.57-1.08; OR, 0.8) and stroke-free survival (86.8% and 88.1%, respectively; 95% CI, 0.59-1.07; OR, 0.8). Diabetic patients had decreased severe (>70%) restenosis-free survival rates at 7 years than nondiabetics (77.4% and 82.2%, respectively; 95% CI, 0.6-1; OR, 0.8; P = .05). Univariate analysis demonstrated again that the use of instrumental cerebral monitoring significantly decreased stroke-free survival in diabetics (P = .01; log rank, 10.1), and this was also confirmed by multivariate analysis (95% CI, 1.7-17.7; OR, 5.4; P = .005). CONCLUSIONS In our experience, the presence of diabetes mellitus increases three-fold the risk of perioperative death after CEA, while there are no differences with nondiabetics in terms of perioperative stroke. However, the rate of stroke and death at 30 days still remains below the recommended standards. During follow-up, this difference becomes negligible, and results are fairly similar to those obtained in nondiabetics. Particular attention should be paid to patients undergoing intervention under general anesthesia, who seem to represent a subgroup of diabetics at higher perioperative risk, suggesting neurologic monitoring should be used when possible.


Journal of Vascular Surgery | 2009

Carotid endarterectomy in female patients

Walter Dorigo; Raffaele Pulli; John Marek; Nicola Troisi; Giovanni Pratesi; Alessandro Alessi Innocenti; Carlo Pratesi

OBJECTIVES To evaluate early and late results of carotid endarterectomy (CEA) in female patients in a large single center experience. METHODS Over a 12-year period ending in December 2007, 4009 consecutive primary and secondary CEAs in 3324 patients were performed at our institution. All patients were prospectively enrolled in a dedicated database containing pre-, intra-, and postoperative parameters. Patients were female in 1200 cases (1020 patients; Group 1) and male in the remaining 2809 (2304 patients, Group 2). Early results in terms of intraoperative neurological events and 30-day stroke and death rates were analyzed and compared. Follow-up results were analyzed with Kaplan Meier curves and compared with log-rank test. RESULTS Patients of Group 1 were more likely to have hyperlipemia, diabetes, and hypertension; patients of Group 2 were more likely to be smokers and to have concomitant coronary artery disease (CAD) and peripheral arterial disease (PAD). There were no differences in terms of clinical status or degree of stenosis. Patients of Group 2 had a significantly higher percentage of contralateral carotid artery occlusion than patients in Group 1 (6.9% and 3.9%, respectively; P < .001). Thirty-day stroke and death rates were similar in the two groups (1.2% for both groups). Univariate analysis demonstrated the presence of CAD, PAD, diabetes, and contralateral carotid artery occlusion to significantly affect 30-day stroke and death rate in female patients. At multivariate analysis, only diabetes (odds ratio [OR] 3.6, 95% confidence interval [CI] 0.1-0.9; P = .05) and contralateral occlusion (OR 7.4, 95% CI 0.03-0.6; P = .006) were independently associated with an increased perioperative risk of stroke and death. Median duration of follow-up was 27 months (range, 1-144 months). There were no overall differences between the two groups in terms of survival, freedom from ipsilateral stroke, freedom from any neurological symptom, and incidence of severe (>70%) restenosis. In contrast to male patients, univariate and multivariate analysis demonstrated that female patients with diabetes or contralateral occlusion had an increased risk of developing ipsilateral neurological events during follow-up. CONCLUSIONS Female sex per se does not represent an adjunctive risk factor during CEA, with early and long term results comparable to those obtained in male patients. However, in our study we found subgroups of female patients at higher surgical risk, requiring careful intra- and postoperative management.


Annals of Vascular Surgery | 2010

Post-Endovascular Aneurysm Repair Patient Outcomes and Follow-up Are Not Adversely Impacted By Long Travel Distance to Tertiary Vascular Surgery Centers

Dusadee Sarangarm; Jordan Knepper; John Marek; Kristen L. Biggs; Diane Robertson; Mark Langsfeld

BACKGROUND To determine whether patient adherence to follow-up and patient outcomes after endovascular aneurysm repair (EVAR) are affected by the distance between a patients residence and a tertiary care treatment center. METHODS A retrospective review of 136 consecutive patients undergoing EVAR at the New Mexico Veterans Affairs Medical Center over a 7-year period was conducted. Patients were stratified as living within a 100-mi radius of the treatment center (group 1) and those living outside this radius (group 2). Follow-up included clinic visits and computed tomography scans at 1 month after discharge, every 6 months for 2 years, and then yearly. Incomplete follow-up was defined if two or more consecutive appointments were missed. Survival and graft-related complication rates were analyzed for both the patient groups. RESULTS Of the 136 patients, 10 patients died from nonaneurysm-related causes less than 1 year after their EVAR procedures, and hence were not a part of the study. Of the surviving patients, 44% lived within a 100-mi radius of the treatment center (group 1), and 56% outside this 100-mi radius (group 2). The mean patient follow-up time was 52.1 ± 25.9 months. Of the surviving patients, 15% had inadequate follow-up, yet there was no significant difference in the adequacy of follow-up for patients in group 1 compared with group 2. The incidence of major complications, defined as aneurysm rupture, conversion to open repair, myocardial infarction, and stroke, was not statistically different in group 1 versus group 2 (5.0% vs. 11.8%, p = 0.23). Of the five patients (3.7%) who died as a result of abdominal aortic aneurysms related causes, three were in group 1 and two in group 2. CONCLUSIONS Distance from a tertiary care center is not a limiting factor in patient adherence to follow-up, patient graft-related morbidity, or patient survival, likely because of the Albuquerque VA Medical Centers electronic tracking of patients and provision of travel vouchers.


American Journal of Surgery | 2003

Comparison of nonneurological events in high-risk patients treated by carotid angioplasty versus endarterectomy

Karthikeshwar Kasirajan; Brian Matteson; John Marek; Mark Langsfeld

OBJECTIVE To compare results of carotid angioplasty and stenting (CAS) with carotid endarterectomy (CEA) in high cardiac risk patients. METHODS Patients ineligible for carotid revascularization by North American Symptomatic Carotid Endarterectomy Trial/Asymptomatic Carotid Atherosclerosis Study criteria were treated with CAS (n = 11) or CEA (n = 10). RESULTS Significant numbers had cardiac (CAS 72%, CEA 60%; P = 0.66) and hypertensive (CAS 82%, CEA 80%; P = 0.64) risk factors. Adverse hemodynamic events were more frequent in the CAS group (CAS 73%, CEA 20%; P = 0.03). Major complications were noted in 1 patient in each group (CAS, myocardial infarction; CEA, death). Postoperative stay was similar (CAS 2.1 +/- 1.4, CEA 1.8 +/- 1.1 days; P = 0.60). However, 4 in the CAS group were readmitted within 1 month (congestive heart failure 2, myocardial infarction 1, rest pain 1), compared with no new events in the CEA group (P = 0.09). CONCLUSIONS Currently, the use of CAS in patients with cardiac risk factors may not be justifiable.


Annals of Vascular Surgery | 2010

Combined Carotid and Cardiac Surgery: Improving the Results

Emiliano Chiti; Nicola Troisi; John Marek; Walter Dorigo; Alessandro Alessi Innocenti; Raffaele Pulli; Pierluigi Stefano; Carlo Pratesi

BACKGROUND Aim of this study was to analyze our experience in the last 5 years of combined carotid and cardiac surgery. METHODS During a 5-year period (January 2002-December 2006), 111 patients underwent combined carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG) (group 1), while 1,446 patients underwent isolated CEA (group 2). Perioperative outcomes in the two groups were compared using chi(2) and Fishers exact tests to analyze neurological deficits, cardiac events, and death at 30 days. Results during follow-up were analyzed using Kaplan-Meier survival curves, and both groups were compared using the log-rank test. RESULTS Immediate postoperative neurological deficits occurred more frequently in group 1 patients (2.5 vs. 0.4%, p = 0.002), with a higher incidence of transient ischemic attacks in group 1; however, there was no difference in the incidence of stroke (1% group 1 vs. 0.6% group 2, p = n.s.). Mortality rate was increased in the combined surgery group (3.5 vs. 0.5%, p < 0.001). Combined stroke/myocardial infarction/death rate at 30 days was 6.3% in group 1 compared with 1.4% in group 2, p = 0.001. Perioperative stroke/myocardial infarction/death rate was much improved in the 55% (61/111) of patients undergoing CABG off-pump (3.3 vs. 10%, p = 0.001). Mean follow-up was 18.7 months (range, 1-60). Survival at 24 months was significantly higher in patients of group 2 compared with group 1 (99.4 vs. 91.3% respectively, p < 0.001). At 24 months, there was no significant difference between the two groups in the risk of developing ipsilateral or contralateral neurologic events (3.1% group 1 vs. 1.7% group 2). CONCLUSION In our experience, combined CEA and cardiac surgery carries a higher risk of perioperative mortality than patients undergoing isolated CEA. Whenever possible, CEA combined with off-pump CABG seems to be the therapeutic strategy of choice.

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Mark Langsfeld

University of New Mexico

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Brian Matteson

University of New Mexico

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Barkat Ali

University of New Mexico

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