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Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 12/2012; 56(6):1829. · 3.52 Impact Factor
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ABSTRACT: Computed tomography (CT) scans are routinely used for graft surveillance in patients who have had endovascular repair (EVAR) of an abdominal aortic aneurysm. There is a growing concern for cancers associated with inadvertent use of CT scans. We report the estimated risk of radiation associated solid organ malignancy caused by routine surveillance CT after EVAR using the Biological Effects of Ionizing Radiation (BEIR VII) model created by U.S. National Institute of Science and National Research Council.
Our study estimated the excess relative risk (ERR) of a patient acquiring a solid organ malignancy secondary to radiation exposure from postoperative EVAR surveillance CT imaging. The radiation dose was calculated in sieverts (Sv). The ERR of solid organ malignancy, as given by the BEIR VII model, is = β(s) D exp {γe*} (a/60)(η), where β(s), γ, and η are data-derived parameters, e is age at exposure, and e* = (e-30)/10 for e < 30 and zero for e ≥ 30, a is attained age, and D is dose in sieverts. Dose-weighted ERRs were calculated to allow a comparison of malignancy risk when using a CT at all time points (model 1: 0, 1, 6, 12, and 18 months, 2, 3, and 4 years, and yearly thereafter) vs replacing the CT scan with two other models (model 2: CT once in 3 years) and (model 3: CT once in 5 years). The risk was stratified by age groups, sex, and use of two different radiation doses (15 or 31 mSv) per CT scan. Statistical analysis used the paired t test.
There were significant differences between the ERR of solid organ malignancy in those patients who would undergo surveillance CTs at all time points vs those whose surveillance consisted of alternative modalities at some time points (P < .0001). The cumulative ERR of cancer from radiation was higher in those exposed to contrast-enhanced CT scans, younger people, with highest in the group aged 50 to 55 years (ERR, 0.43), and lowest in patients aged ≥80 years (ERR, 0.10).
Patients undergoing routine CT scans for postoperative surveillance after EVAR are at risk for acquiring new solid organ malignancy due to radiation exposure. The risk is higher in young patients, women, and those exposed to multiple contrast-enhanced CT scans. Our analysis questions the need for routine surveillance CT scans after EVAR in the absence of endoleaks or a change in aneurysm morphology, based on an increased malignancy risk.
Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 07/2012; 56(4):929-37. · 3.52 Impact Factor
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ABSTRACT: Acute limb ischemia (ALI) in infants is a catastrophic event. We performed a query of our database to determine those with ALI. Twelve patients were identified. The most frequent presentation was cyanotic limbs. Eleven patients were treated nonoperatively with anticoagulation. One patient was treated surgically with Fogarty balloon thrombectomy. There were three deaths all due to associated comorbidities. All had viable limbs on follow-up examination. There were three complications in the patients managed conservatively. Our recommendation for infants presenting with ALI is conservative observation with anticoagulation and intervention only for cases with tissue loss.
Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 11/2011; 55(4):1156-9; discussion 1158-9. · 3.52 Impact Factor
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Michael C Dalsing
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ABSTRACT: The physician/surgeon's interactions with industry have come under scrutiny in recent years for several reasons. Although some think that the professional medical association or society may provide an avenue to allow such interactions with less risk, there are concerns and challenges for such organizations as it relates to ethical and professional norms of their members. This is one surgeon's review of some pertinent information regarding what the professional medical society provides to its members and what role industry plays in the society's ability to provide these benefits. There is an exploration of the risks involved and practical methods to control inherent conflicts of interest involved in this interaction.
Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 09/2011; 54(3 Suppl):41S-6S. · 3.52 Impact Factor
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ABSTRACT: The purpose of this Phase I open label nonrandomized trial was to assess the safety and efficacy of autologous bone marrow mononuclear cell (ABMNC) therapy in promoting amputation-free survival (AFS) in patients with critical limb ischemia (CLI).
Between September 2005 and March 2009, 29 patients (30 limbs), with a median age of 66 years (range, 23-84 years; 14 male, 15 female) with CLI were enrolled. Twenty-one limbs presented with rest pain (RP), six with RP and ulceration, and three with ulcer only. All patients were not candidates for surgical bypass due to absence of a patent artery below the knee and/or endovascular approaches to improving perfusion was not possible as determined by an independent vascular surgeon. Patients were treated with an average dose of 1.7 ± 0.7 × 10(9) ABMNC injected intramuscularly in the index limb distal to the anterior tibial tuberosity. The primary safety end point was accumulation of serious adverse events, and the primary efficacy end point was AFS at 1 year. Secondary end points at 12 weeks posttreatment were changes in first toe pressure (FTP), toe-brachial index (TBI), ankle-brachial index (ABI), and transcutaneous oxygen measurements (TcPO(2)). Perfusion of the index limb was measured with positron emission tomography-computed tomography (PET-CT) with intra-arterial infusion of H(2)O(15). RP, using a 10-cm visual analogue scale, quality of life using the VascuQuol questionnaire, and ulcer healing were assessed at each follow-up interval. Subpopulations of endothelial progenitor cells were quantified prior to ABMNC administration using immunocytochemistry and fluorescent-activated cell sorting.
There were two serious adverse events; however, there were no procedure-related deaths. Amputation-free survival at 1 year was 86.3%. There was a significant increase in FTP (10.2 ± 6.2 mm Hg; P = .02) and TBI (0.10 ± 0.05;P = .02) and a trend in improvement in ABI (0.08 ± 0.04; P = .73). Perfusion index by PET-CT H(2)O(15) increased by 19.3 ± 3.1, and RP decreased significantly by 2.2 ± 0.6 cm (P = .02). The VascuQol questionnaire demonstrated significant improvement in quality of life, and three of nine ulcers (33%) healed completely. KDR(+) but not CD34(+) or CD133(+) subpopulations of ABMNC were associated with improvement in limb perfusion.
This Phase I study has demonstrated safety, and the AFS rates suggest efficacy of ABMNC in promoting limb salvage in "no option" CLI. Based on these results, we plan to test the concept that ABMNCs improve AFS at 1 year in a Phase III randomized, double-blinded, multicenter trial.
Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 06/2011; 53(6):1565-74.e1. · 3.52 Impact Factor
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ABSTRACT: The continued advancement of RFA and EVLS technology should provide for an increased safety profile and lasting efficacy for treating the major saphenous veins. The challenge lies in determining what type of patient comorbidities and anatomic variability result in higher recurrences after endothermal varicose vein treatment so that one can modify the choice of treatment appropriately. Further standardization of the FS technique may allow for its wider use in treating truncal varicosities. The powered phlebectomy system seems to be suited for isolated branch varicosities, but the sequelae of pain and ecchymosis may prevent it from becoming a mainstream treatment with stab phlebectomy and sclerotherapy as alternatives.
Advances in Surgery 01/2011; 45:45-62.
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ABSTRACT: Patients with iliofemoral deep venous thrombosis (DVT) are at highest risk for the postthrombotic morbidity including all aspects of the postthrombotic syndrome. Invasive therapies such as catheter-directed thrombolysis (CDT) and/or mechanical thrombectomy with or without angioplasty and stenting and in some cases open operative thrombectomy improves venous patency, venous valve function, and quality of life in patients with acute iliofemoral DVT. What is the current frequency of acute iliofemoral DVT and how aggressively is it being treated? We hypothesize that the 10-year period frequency of iliofemoral DVT among acute DVT cases is greater than previously reported. Further, we hypothesize that thrombus removal to treat acute iliofemoral DVT is little utilized in current practice.
Indiana University (IU) vascular laboratory records from January 1, 1998 to December 31, 2008 were searched by CPT code for venous Doppler ultrasound study (n=7240). A random sample based on the IU medical record number of lower extremity Doppler studies was then selected (n=1020) for retrospective chart review. Corresponding clinical information was gathered from the patients' electronic medical record.
Acute DVT occurred in 6.8%, and chronic DVT in 8.8% of patients studied (25.7% inpatient, 61.7% female; median age, 56.0 years [range, 4-91 years, 1.1% less than 16 years]). History of previous DVT (33.3%) and cancer (30.4%) were the most common risk factors in patients with acute DVT. Iliofemoral DVT defined as having an iliac or common femoral vein component was identified in 49.3% of acute DVT and in 36.0% of chronic DVT. CDT was utilized in 14.3% and mechanical thrombectomy in 4.8% of acute iliofemoral DVT, and was never used with distal DVT. Warfarin anticoagulation+unfractionated heparin or low-molecular-weight heparin overlap was the most common treatment for acute iliofemoral DVT (100.0%). In 2008, the referral base of our laboratory increased significantly. Acute DVT occurred significantly less often during the 1-year period 2008 (5.3%) than the 10-year period 1998-2007 (7.6%), but iliofemoral+common femoral DVT as a component of acute DVT did not differ significantly.
Iliofemoral DVT may be more frequent than previously reported and represents a significant portion of acute DVT. Current recommendations of acute thrombus removal for the treatment of iliofemoral DVT is underutilized suggesting that perhaps greater education of clinicians and patients regarding invasive therapy for iliofemoral DVT is required.
Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 11/2010; 52(5):1272-7. · 3.52 Impact Factor
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ABSTRACT: Peripheral arterial disease is a major health problem and there is a significant need to develop therapies to prevent its progression to claudication and critical limb ischemia. Promising results in rodent models of arterial occlusion have generally failed to predict clinical success and led to questions of their relevance. While sub-optimal models may have contributed to the lack of progress, we suggest that advancement has also been hindered by misconceptions of the human capacity for compensation and the specific vessels which are of primary importance. We present and summarize new and existing data from humans, Ossabaw miniature pigs, and rodents which provide compelling evidence that natural compensation to occlusion of a major artery (i) may completely restore perfusion, (ii) occurs in specific pre-existing small arteries, rather than the distal vasculature, via mechanisms involving flow-mediated dilation and remodeling (iii) is impaired by cardiovascular risk factors which suppress the flow-mediated mechanisms and (iv) can be restored by reversal of endothelial dysfunction. We propose that restoration of the capacity for flow-mediated dilation and remodeling in small arteries represents a largely unexplored potential therapeutic opportunity to enhance compensation for major arterial occlusion and prevent the progression to critical limb ischemia in the peripheral circulation.
Microcirculation (New York, N.Y.: 1994) 01/2010; 17(1):3-20. · 2.37 Impact Factor
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ABSTRACT: Percutaneous transluminal angioplasty (PTA) has become an accepted treatment for atherosclerotic arterial occlusive disease
in properly selected patients. Delivery systems and balloon designs have matured over the last three decades, resulting in
improved PTA results and fewer procedural complications [1]. However, this technique does have its limitations. Our personal
experience with early technical failures and postprocedural restenosis forced a reevaluation of the technique and a consideration
of methods that might improve results in areas of difficulty [2, 3]. The use of supportive endoskeletons (stents), although
suggested by Dotter during the late 1960s, was not pursued until the limitations of PTA were widely recognized [4].
KeywordsIntravascular stents-Percutaneous transluminal angioplasty-Atherosclerotic arterial occlusive disease
12/2009: pages 225-256;
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Michael C Dalsing
Bulletin of the American College of Surgeons 09/2009; 94(8):24-5, 47.
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Matthew R Distasi,
Jamie Case,
Matthew A Ziegler,
Mary C Dinauer,
Mervin C Yoder,
Laura S Haneline, Michael C Dalsing,
Steven J Miller,
Carlos A Labarrere,
Michael P Murphy,
David A Ingram,
Joseph L Unthank
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ABSTRACT: While tissue perfusion and angiogenesis subsequent to acute femoral artery occlusion are suppressed in NADPH oxidase 2 (Nox2)-null (Nox2(-/-)) mice, studies have not established the role of Nox2 in collateral artery enlargement. Rac2 is a small GTPase that binds Nox2 and activates Nox2-based NAD(P)H oxidase but, unlike Nox2, is primarily restricted to bone marrow-derived cells. In this study, we used Rac2-null (Rac2(-/-)) and Nox2(-/-) mice with a novel method of identifying primary hindlimb collaterals to investigate the hypothesis that collateral growth requires these molecules. When initial experiments performed with femoral ligation demonstrated similar perfusion and collateral growth in Rac2(-/-) and wild-type C57BL/6J (BL6) mice, subsequent experiments were performed with a more severe ischemia model, femoral artery excision. After femoral excision, tissue perfusion was suppressed in Rac2(-/-) mice relative to BL6 mice. Histological assessment of ischemic injury including necrotic and regenerated muscle fibers and lipid and collagen deposition demonstrated greater injury in Rac2(-/-) mice. The diameters of primary collaterals identified during Microfil injection with intravital microscopy were enlarged to a similar extent in BL6 and Rac2(-/-) mice. Intimal cells in collateral cross sections were increased in number in both strains and were CD31 positive and CD45 negative. Circulating leukocytes and CD11b(+) cells were increased more in Rac2(-/-) than BL6 animals. Experiments performed in Nox2(-/-) mice to verify that the unexpected results related to collateral growth were not unique to Rac2(-/-) mice gave equivalent results. The data demonstrate that, subsequent to acute femoral artery excision, perfusion recovery is impaired in Rac2(-/-) and Nox2(-/-) mice but that collateral luminal expansion and intimal cell recruitment/proliferation are normal. These novel results indicate that collateral luminal expansion and intimal cell recruitment/proliferation are not mediated by Rac2 and Nox2.
AJP Heart and Circulatory Physiology 02/2009; 296(3):H877-86. · 3.71 Impact Factor
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Michael C Dalsing
Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 02/2009; 49(1):162. · 3.52 Impact Factor
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ABSTRACT: The optimal prophylactic strategy and treatment regimen for deep venous thrombosis (DVT) in hospitalized pediatric patients is not clearly established. This study assessed the incidence, risk factors, and treatment patterns for DVT among pediatric patients admitted to a hospital ward.
Children (aged <17 years) admitted to a single tertiary-care hospital during a 14-year period who developed or presented with DVT were retrospectively identified. Patient demographic and clinical data were analyzed retrospectively. Patients who developed DVT in the hospital were stratified according to the Wells clinical probability scoring system from criteria noted before the diagnosis. Treatment patterns and outcomes were evaluated between the two time intervals of 1992 to 2001 (group I) and 2002 to 2005 (group II).
Between 1992 and 2005, 358 children were evaluated for DVT, and 99 (52 boys, 47 girls) were admitted to the hospital and were determined to have DVT by confirmatory imaging. A prior DVT (12 total) was present in eight of the 21 patients admitted for DVT treatment; of the remaining, only seven received DVT prophylaxis on admission. In those developing a DVT, the inpatient clinical probability score was 21% (low), 40% (moderate), and 39% (high). The most common risk factor in those with prehospital DVT was a prior DVT (38%) or thrombophilic condition (33%), whereas inpatients had a central catheter (45%), with nearly 50% in the femoral vein. Children acquiring an inpatient DVT had concomitant severe respiratory (17%), oncologic (14%), and/or infectious (15%) diseases and required a prolonged intensive care unit (12.7 days) stay. Prehospital DVT was lower extremity predominant (90%) and statistically different from inpatient-acquired DVT (62%, P = .01). Treatment patterns between periods I and II revealed a trend to more low-molecular-weight heparin and less unfractionated heparin use (P = .09). Three patients died (one fatal pulmonary embolism). The number of recognized cases per 10,000 admissions increased from 0.3 to 28.8 from 1992 to 2005.
The incidence of DVT in hospitalized children is increasing. Those presenting with DVT typically have prior DVT, thrombophilia, or lower extremity disease. Our study suggests that children admitted with severe medical conditions who require a prolonged intensive care unit stay in addition to central venous access (especially via the femoral vein) should be considered candidates for DVT prophylaxis. A clinical probability scoring system alone cannot stratify patients sufficiently to forgo prophylaxis in hopes of a rapid clinical diagnosis. Childhood-specific level 1 trials aimed at determining guidelines for DVT prophylaxis are urgently required.
Journal of Vascular Surgery 04/2008; 47(4):837-43. · 3.21 Impact Factor
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ABSTRACT: Available studies indicate that both genetic background and aging influence collateral growth capacity, but it is not known how their combination affects collateral growth. We evaluated collateral growth induced by ileal artery ligation in Fischer 344 (F344), Brown Norway (BN), and the first generation hybrid of F344 x BN (F1) rats available for aging research from the National Institute on Aging. Collateral growth was determined by paired diameter measurements in anesthetized rats immediately and 7 days postligation. In 3-mo-old rats, significant collateral growth occurred only in BN (35% +/- 11%, P < 0.001). The endothelial cell number in arterial cross sections was also determined, since this precedes shear-mediated luminal expansion. When compared with the same animal controls, the intimal cell number was increased only in BN rats (92% +/- 21%, P < 0.001). The increase in intimal cell number and the degree of collateral luminal expansion in BN rats was not affected by age from 3 to 24 mo. Immunohistochemical studies demonstrated that intimal cell proliferation was much greater in the collaterals of BN than of F1 rats. The remarkable difference between these three strains of rats used in aging research and the lack of an age-related impairment in the BN rats are novel observations. These rat strains mimic clinical observations of interindividual variation in collateral growth capacity and the impact of age on arteriogenesis and should be useful models to investigate the molecular mechanisms responsible for such differences.
AJP Heart and Circulatory Physiology 01/2008; 293(6):H3498-505. · 3.71 Impact Factor
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Michael C Dalsing
Journal of Vascular Surgery 08/2007; 46(1):156-62. · 3.21 Impact Factor
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ABSTRACT: Recent clinical and animal studies have shown that collateral artery growth is impaired in the presence of vascular risk factors, including hypertension. Available evidence suggests that angiotensin-converting enzyme inhibitors (ACEI) promote collateral growth in both hypertensive humans and animals; however, the specific mechanisms are not established. This study evaluated the hypothesis that collateral growth impairment in hypertension is mediated by excess superoxide produced by NAD(P)H oxidase in response to stimulation of the ANG II type 1 receptor. After ileal artery ligation, mesenteric collateral growth did not occur in untreated, young, spontaneously hypertensive rats. Significant luminal expansion occurred in collaterals of spontaneously hypertensive rats treated with the superoxide dismutase mimetic tempol, the NAD(P)H oxidase inhibitor apocynin, and the ACEI captopril, but not ANG II type 1 (losartan) or type 2 (PD-123319) receptor blockers. The ACEI enalapril produced equivalent reduction of arterial pressure as captopril but did not promote luminal expansion. This suggests the effects of captopril on collateral growth might result from its antioxidant properties. RT-PCR demonstrated that ANG II type 1 receptor and angiotensinogen expression was reduced in collaterals of untreated rats. This local suppression of the renin angiotensin system provides a potential explanation for the lack of effect of enalapril and losartan on collateral growth. The results demonstrate the capability of antioxidant therapies, including captopril, to reverse impaired collateral artery growth and the novel finding that components of the local renin angiotensin system are naturally suppressed in collaterals.
AJP Heart and Circulatory Physiology 06/2007; 292(5):H2523-31. · 3.71 Impact Factor
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ABSTRACT: Mesenteric arterial branch aneurysms are rare. Giant, multiple, mesenteric branch artery aneurysms are even more uncommon, and only a few reports exist in the literature. We describe a 73-year-old asymptomatic female found to have an abdominal bruit and subsequently diagnosed with multiple mesenteric branch artery aneurysms by computed tomography and angiography. In addition, the patient was found to have celiac artery occlusion at its origin. Risk factors include hypertension, hyperlipidemia, grandmultiparity, and tobacco dependence. She was treated successfully with open surgery including ligation of multiple branch aneurysms and vein bypass reconstruction to preserve hepatic and mesenteric artery flow. Our purpose is to review this uncommon entity in terms of diagnosis, etiology, treatment options, and literature review.
Annals of Vascular Surgery 06/2007; 21(3):280-3. · 1.03 Impact Factor
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ABSTRACT: There are multiple endovascular options to achieve percutaneous revascularization of chronic superficial femoral artery (SFA) stenoses and occlusions. Most rely on forceful displacement of plaque via balloon angioplasty, either as a stand-alone therapy or supplemented by cold thermal injury (cryoplasty), microtome assistance (cutting balloon angioplasty), nitinol stent deployment, or expanded polytetrafluoroethylene-lined nitinol stent deployment. Excellent technical success rates are routinely described in the literature. The essential problem associated with these techniques is the predictable compromise of the initial result by neointimal hyperplasia leading to poor long-term results. An alternative to forceful displacement techniques is use of directional atherectomy or excimer laser to debulk the atheromatous lesion, with the addition of low-pressure angioplasty or stent deployment as needed. Currently, directional atherectomy is performed using the Silverhawk Plaque Excision System (FoxHollow, Redwood City, CA), while laser atherectomy is frequently performed with the CLIRpath Excimer Laser (Spectranetics Corp., Colorado Springs, CO). While both techniques can be utilized for de novo atherosclerotic lesions, even eccentric lesions or ostial lesions, proponents of these devices have also shown good short-term results in the treatment of restenoses. Remote SFA endarterectomy with the Aspire stent (Vascular Architects, San Jose, CA) is a hybrid surgical and endovascular technique that is useful for debulking plaque from the SFA with adjunctive stenting of the distal SFA. We present a review of various alternative techniques to forceful balloon dilation used in the recanalization of the SFA with potential pitfalls and complications, along with a review of literature associated with each of these techniques.
Seminars in Vascular Surgery 04/2007; 20(1):29-36. · 1.71 Impact Factor
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Michael C Dalsing
Journal of Vascular Surgery 02/2007; 45(1):206-13. · 3.21 Impact Factor
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ABSTRACT: Vagal nerve stimulation therapy is a new adjunctive treatment for drug-resistant epilepsy and depression. It consists of a pulse generator that transmits impulses to the left vagus nerve via an implantable electrode and can be performed by surgeons familiar with the anatomy of the cervical vagus nerve. The minimum age for vagal nerve stimulation therapy for epilepsy is 12 years, and for depression, 18 years. Hoarseness and cough are the most common side effects. Response rates to vagal nerve stimulation therapy vary and depend on several other factors. If used as adjunctive therapy, vagal nerve stimulation has shown better control of seizures or depression at smaller doses of antiepileptic or antidepressive medications and also results in decreased dose-dependent side effects. Vagal nerve stimulation therapy appears safe as an adjunctive treatment for drug-resistant epilepsy and depression. Long-term data are needed to better define its ultimate role in various subsets of patients.
Perspectives in Vascular Surgery and Endovascular Therapy 01/2007; 18(4):323-7.
