Impact of Continued Clopidogrel use on Outcomes of Patients undergoing Carotid Endarterectomy

OBJECTIVES

To evaluate the use of clopidogrel at the time of carotid endarterectomy (CEA) and its association with postoperative complications.

METHODS

Single institution, retrospective review of a prospective database.

RESULTS

From 2010 to 2017, CEA was performed in 1066 consecutive patients (median age 73 years, 66% men). The indications for operation included ≥70% asymptomatic stenosis (458, 43%), prior stroke (314, 29%), and transient cerebral or retinal ischemia (294, 28%). At the time of operation, 509 (48%) patients were taking aspirin alone, 441 (41%) were taking clopidogrel (374 in combination with aspirin, 67 as sole therapy), 83 (8%) were on no documented antiplatelet medication, and 33 (3%) were taking warfarin (with therapeutic INR). The likelihood of clopidogrel use at the time of operation was higher for patients with a history of symptomatic carotid disease (p=0.002). Over the study period, clopidogrel use increased from 31.9% in 2010 to, 56.8% in 2017 that corresponds to 11% 95%CI (6, 15) increase annually. Postoperative strokes occurred in 15 patients (overall incidence 1.4%), the majority of which were minor (12/15, 80%). Six strokes occurred in patients taking aspirin alone (6/509, 1.2%), 2 in patients on clopidogrel and aspirin (2/441, 0.5%), 2 in patients taking clopidogrel alone (2/67, 2.9%), 3 in patients on no documented antiplatelet medication (3/83, 3.6%), and 2 in those taking warfarin (one of which was secondary to a fatal intracranial hemorrhage within 30 d of discharge; 2/33, 6.1%). The 30-day mortality rate was 0.03% (3/1066); the risk for the combined endpoint of any stroke, death or myocardial infarction (MI) was 2.3% (25/1066), and the risk for major stroke, death, or MI was 1.2%. There was no apparent association between clopidogrel use and the incidence of postoperative bleeding (p=0.59) or any other postoperative complication (stroke, death, MI, cranial nerve injury, p=0.15).

CONCLUSIONS

Clopidogrel use in our CEA practice has increased over time and has not been associated with an increased risk of postoperative complications, including bleeding. These data suggest that clopidogrel should not be discontinued prior to CEA, and should be considered as part of 'optimal medical therapy' in patients undergoing CEA.

Hematopoietic Stem Cell-Derived Adipocytes Modulate Adipose Tissue Cellularity, Leptin Production and Insulin Responsiveness in Female Mice

A subpopulation of adipocytes in the major adipose depots of mice is produced from hematopoietic stem cells rather than mesenchymal progenitors that are the source of conventional white and brown/beige adipocytes. To analyze the impact of hematopoietic stem cell-derived adipocytes (HSCDAs) in the adipose niche we transplanted HSCs in which expression of a diphtheria toxin gene was under the control of the adipocyte-specific adiponectin gene promoter into irradiated wild type recipients. Thus, only adipocytes produced from HSC would be ablated while conventional white and brown adipocytes produced from mesenchymal progenitor cells would be spared. Wild type mice transplanted with HSCs from mice containing a reporter gene, but not the diphtheria toxin gene, regulated by the adiponectin gene promoter served as controls. In mice in which HSCDA production was suppressed, adipocyte size declined while adipose depot weights were unchanged and the number of conventional adipocyte progenitors significantly increased. We also measured a paradoxical increase in circulating leptin levels while physical activity was significantly decreased in the HSCDA depleted mice. Finally, insulin sensitivity was significantly reduced in HSCDA depleted mice. In contrast, loss of HSCDA production had no effect on body weight, components of energy balance, or levels of several circulating adipokines and tissue-resident inflammatory cells. These data indicate that ablation of this low-abundance subpopulation of adipocytes is associated with changes in circulating leptin levels and leptin-regulated endpoints associated with adipose tissue function. How they do so remains a mystery, but our results highlight the need for additional studies to explore the role of HSCDAs in other physiologic contexts such as obesity, metabolic dysfunction or loss of sex hormone production.

Hematopoietic stem cells produce intermediate lineage adipocyte progenitors that simultaneously express both myeloid and mesenchymal lineage markers in adipose tissue

Some adipocytes are produced from bone marrow hematopoietic stem cells. In vitro studies previously indicated that these bone marrow-derived adipocytes (BMDAs) were generated from adipose tissue macrophage (ATM) that lose their hematopoietic markers and acquire mesenchymal markers prior to terminal adipogenic differentiation. Here we interrogated whether this hematopoietic-to-mesenchymal transition drives BMDA production In vitro. We generated transgenic mice in which the lysozyme gene promoter (LysM) indelibly labeled ATM with green fluorescent protein (GFP). We discovered that adipose stroma contained a population of LysM-positive myeloid cells that simultaneously expressed hematopoietic/myeloid markers (CD45 and CD11b), and mesenchymal markers (CD29, PDGFRa and Sca-1) typically found on conventional adipocyte progenitors. These cells were capable of adipogenic differentiation In vitro and In vitro, while other stromal populations deficient in PDGFRa and Sca-1 were non-adipogenic. BMDAs and conventional adipocytes expressed common fat cell markers but exhibited little or no expression of hematopoietic and mesenchymal progenitor cell markers. The data indicate that BMDAs are produced from ATM simultaneously expressing hematopoietic and mesenchymal markers rather than via a stepwise hematopoietic-to-mesenchymal transition. Because BMDA production is stimulated by high fat feeding, their production from hematopoietic progenitors may maintain adipocyte production when conventional adipocyte precursors are diminished.

Treatment of Femoropopliteal Lesions With the BioMimics 3D Vascular Stent System: Two-Year Results From the MIMICS-2 Trial

PURPOSE

To report the safety and effectiveness outcomes through 2 years of the BioMimics 3D Vascular Stent System in the treatment of symptomatic patients with atherosclerotic femoropopliteal disease.

MATERIALS AND METHODS

The tubular, nitinol BioMimics 3D stent, which was designed to impart a helical shape to the arterial segment, was implanted in 271 patients (mean age 68.4±9.5 years; 180 men) with de novo femoropopliteal lesions enrolled at 43 investigational sites [31 US (n=162), 6 German (n=78), and 6 Japanese (n=31)] in the prospective, single-arm MIMICS-2 investigational device exemption trial (ClinicalTrials.gov identifier NCT02400905) between June 2015 and October 2016. Mean lesion length was 81.2±38.4 mm, 30.0% of patients had total occlusions, and 45.9% had moderate to severe calcification. Primary safety and effectiveness endpoints were compared at 1 year with prespecified objective performance goals (OPGs) set by the VIVA Physicians organization. Outcomes through 2 years are reported.

RESULTS

The primary effectiveness endpoint of 12-month primary stent patency was met by 182 of 249 patients (73.1%, 95% CI 67.3% to 78.2%), exceeding the OPG of 66%. The primary safety endpoint of 30-day freedom from major adverse events (MAEs) was met in 268 of 269 patients (99.6%, 95% CI 97.7% to 100%), exceeding the OPG of 88%. Kaplan-Meier estimates of freedom from loss of primary patency were 83.1% at 12 months and 70.2% at 24 months, freedom from MAEs estimates were 86.9% at 12 months and 79.2% at 24 months, and freedom from clinically-driven target lesion revascularization estimates were 88.0% at 12 months and 83.0% at 24 months. At 24 months, 88.2% of patients showed improvement of ≥1 Rutherford category; the ankle-brachial index was >0.9 for 64.4% vs 11.3% at baseline. There were no cases of stent fracture.

CONCLUSION

Through 24 months, the BioMimics 3D Vascular Stent System provided safe and effective treatment for femoropopliteal lesions in patients with symptomatic peripheral artery disease.

Superior mesenteric artery outcomes after large fenestration strut relocation with the Zenith Fenestrated endoprosthesis

Background

The Zenith® Fenestrated (ZFen) stent-graft is frequently configured with a strut-spanning large fenestration for superior mesenteric artery (SMA) incorporation. This has led some to relocate struts to create a strut-free fenestration and place a bridging stent. The aim of this study was to compare SMA outcomes with and without large fenestration strut relocation.

Methods

We performed a retrospective review of a prospective database of patients undergoing fenestrated endovascular repair with ZFen between 2013 and 2019. Those with SMA incorporation using large fenestrations were included and separated into strut relocation (SR) and no relocation (NR) groups. Endpoints included procedural metrics, technical success, major adverse events, and target-vessel instability.

Results

A total of 121 patients (77% male; mean age 76.1 ± 7.1 years) met inclusion criteria, including 94 with SR (78%) and 27 with NR (22%). A total of 369 target-vessels were incorporated, with a mean of 3.0 ± 0.2 per patient, and no differences between groups. Mean operative time, contrast volume, estimated blood loss, fluoroscopy time and radiation dose were lower (p < 0.001) with SR, attributed to increased experience with time. Overall technical success (SR: 100%, NR: 96%, p = 0.22) was 99%. At a mean follow-up of 32 months, there were two endovascular interventions for mesenteric ischemia. One resulted in SMA dissection requiring bypass in the NR group, the other was successful ballooning of the bridging stent with symptom resolution in the SR group.

Conclusions

Relocating the spanning struts does not negatively impact procedural metrics or midterm outcomes. It may facilitate future endovascular interventions.

Lipid-lowering therapies in peripheral artery disease: A review

Peripheral artery disease (PAD) is estimated to affect approximately 8.5 million individuals in the US above the age of 40, and is associated with significant morbidity, mortality, and impairment. Despite the significant adverse limb and cardiovascular (CV) outcomes seen in patients with PAD, there is typically less attention paid to risk factor modification relative to other atherosclerotic diseases such as coronary artery disease (CAD) or stroke. In the current literature, statins have been shown to reduce mortality, major adverse CV events, major adverse limb events, and improve symptomatic outcomes in patients with PAD. In addition, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are emerging as an additional lipid-lowering therapy for patients with PAD. However, despite current guideline recommendations based on growing evidence, patients with PAD are consistently undertreated with lipid-lowering therapies. We provide an extensive literature review and evidence-based recommendations for the use of statins and PCSK9 inhibitors in patients with PAD.

Comparative Long-term Outcomes of Patients with Aortoiliac Occlusive Disease Limited to Common Iliac Arteries Who Underwent Endarterectomy versus Bypass Grafting

BACKGROUND

The objective of this study was to compared outcomes of patients with aortoiliac occlusive disease (AIOD), limited to the common iliac artery, who underwent either aortoiliac thromboendarterectomy (AIE) or aortobiiliac bypass grafting (ABIB).

METHODS

A single-center, retrospective analysis of consecutive patients with AIOD who underwent either AIE or ABIB between 2010 and 2019 from a prospective database. Patients with disease extending to the external iliac or common femoral arteries were excluded. Data collected included demographics, cardiovascular risk factors, indication for surgery, preoperative and postoperative ankle brachial indexes (ABIs), estimated blood loss, major adverse events (MAEs), and long-term patency. The study end point was clinical success, defined as improvement in ABIs with resolution of symptoms. MAEs included return to the operating room for any reason, postoperative myocardial infarction, stroke, pneumonia, or venous thromboembolism.

RESULTS

Thirty-three patients, who met inclusion criteria, underwent repair for AIOD (AIE: 13; ABIB: 20) at our institution during this time. In both groups, there were more women than men (AIE: 11, ABIB: 10) with a mean age of 55 ± 7 years and 58 ± 6 years in the AIE and ABIB group, respectively. Indication for surgery included disabling claudication in 19 patients, ischemic rest pain in 13 patients, and tissue loss in one patient. No difference in cardiovascular risk factors or AIOD severity was noted between groups. Patients in the AIE group had slightly higher body mass index (30 ± 5 vs. 26 ± 6, P = 0.06). Two patients in each group required concomitant renal/mesenteric artery endarterectomy. One patient in the AIE group required bilateral femoral artery exposure and external iliac thrombectomy. MAEs (4 vs. 0) were higher in the ABIB group including, pneumonia in one patient, myocardial infarction in another, return to the operating room for evacuation of hematoma in the third and bypass graft thrombectomy with lower extremity angiography in the fourth patient. There were no differences in the intensive care unit or hospital length of stay between groups. Patients in both groups achieved return of normal ABI and complete resolution of their symptoms. At mean follow-up time of 43.4 ± 25.2 and 52.9 ± 35.4 months in the AIE and ABIB group, respectively, there was no symptomatic recurrence or need for reintervention while two patients in the ABIB group died of non-aortic-related issues.

CONCLUSIONS

Both procedures were safe, effective, and conferred high long-term primary patency with no need for reintervention in patients with AIOD limited to the common iliac arteries.

CREB depletion in smooth muscle cells promotes medial thickening, adventitial fibrosis and elicits pulmonary hypertension

Levels of the cAMP-responsive transcription factor, CREB, are reduced in medial smooth muscle cells in remodeled pulmonary arteries from hypertensive calves and rats with chronic hypoxia-induced pulmonary hypertension. Here, we show that chronic hypoxia fails to promote CREB depletion in pulmonary artery smooth muscle cells or elicit significant remodeling of the pulmonary arteries in mice, suggesting that sustained CREB expression prevents hypoxia-induced pulmonary artery remodeling. This hypothesis was tested by generating mice, in which CREB was ablated in smooth muscle cells. Loss of CREB in smooth muscle cells stimulated pulmonary artery thickening, right ventricular hypertrophy, profound adventitial collagen deposition, recruitment of myeloid cells to the adventitia, and elevated right ventricular systolic pressure without exposure to chronic hypoxia. Isolated murine CREB-null smooth muscle cells exhibited serum-independent proliferation and hypertrophy in vitro and medium conditioned by CREB-null smooth muscle cells stimulated proliferation and expression of extracellular matrix proteins by adventitial fibroblasts. We conclude that CREB governs the pathologic switch from homeostatic, quiescent smooth muscle cells to proliferative, synthetic cells that drive arterial remodeling contributing to the development or pulmonary hypertension.

Inactivation of Tsc2 in Abcg2 lineage-derived cells drives the appearance of polycystic lesions and fibrosis in the adult kidney

Tuberous sclerosis complex 2 (TSC2), or tuberin, is a pivotal regulator of the mechanistic target of rapamycin signaling pathway that controls cell survival, proliferation, growth, and migration. Loss of Tsc2 function manifests in organ-specific consequences, the mechanisms of which remain incompletely understood. Recent single cell analysis of the kidney has identified ATP-binding cassette G2 (Abcg2) expression in renal proximal tubules of adult mice as well as a in a novel cell population. The impact in adult kidney of Tsc2 knockdown in the Abcg2-expressing lineage has not been evaluated. We engineered an inducible system in which expression of truncated Tsc2, lacking exons 36-37 with an intact 3' region and polycystin 1, is driven by Abcg2. Here, we demonstrate that selective expression of Tsc2fl36-37 in the Abcg2pos lineage drives recombination in proximal tubule epithelial and rare perivascular mesenchymal cells, which results in progressive proximal tubule injury, impaired kidney function, formation of cystic lesions, and fibrosis in adult mice. These data illustrate the critical importance of Tsc2 function in the Abcg2-expressing proximal tubule epithelium and mesenchyme during the development of cystic lesions and remodeling of kidney parenchyma.

Ovarian Hormones Regulate the Production of Adipocytes From Bone Marrow-Derived Cells

Sex differences in body fat distribution and menopause-associated shifts in regional adiposity suggest that sex hormones play an important role in regulating the differentiation and distribution of adipocytes, but the underlying mechanisms have not been fully explained. The aim of this study was to determine whether ovarian hormone status influences the production and distribution of adipocytes in adipose tissue arising from bone marrow-derived cells. Nine- to ten-week-old ovariectomized (OVX), surgery naïve (WT), and estrogen receptor alpha knockout (αERKO) mice underwent bone marrow transplantation from luciferase or green fluorescent protein expressing donors. A subset of OVX animals had estradiol (E₂) added back. Eight-weeks posttransplant, whole body and gonadal fat BM-derived adipocyte production was highest in OVX and αERKO mice, which was attenuated in OVX mice by E₂ add-back. All groups demonstrated the highest bone marrow derived adipocyte (BMDA) production in the gonadal adipose depot, a visceral fat depot in mice. Taken together, the loss of ovarian hormones increases the production of BMDAs. If translatable across species, production of BMDA may be a mechanism by which visceral adiposity increases in estrogen-deficient postmenopausal women.

Diagnosis, Management, and Outcome of Aortitis at a Single Center

BACKGROUND

Aortitis is a rare condition with inflammatory or infectious etiology that can be difficult to diagnose due to the highly variable clinical presentation and nonspecific symptoms. However, current literature on the diagnosis, management, and prognosis of aortitis is extremely scarce.

METHODS

We retrospectively reviewed all patients' charts who were diagnosed with giant cell arteritis, Takayasu arteritis, or noninfectious aortitis presenting at a single center between January 1, 2009, and April 17, 2015. Data collected included demographics, medical history, comorbidities, laboratory and imaging data, management, and outcome.

RESULTS

Among the included 15 patients presenting with aortitis at our center, 53% were diagnosed with Takayasu arteritis, 33% with idiopathic inflammatory aortitis, and 13% with giant cell arteritis. All patients received steroid treatment, 67% received adjunctive immunosuppressants or immunomodulators, and 33% underwent interventional procedures. Based on clinical presentation and laboratory and imaging findings at the last follow-up visit for each patient, 67% showed improvement, 27% had no change in disease activity, and 7% had a progression of the disease.

CONCLUSIONS

Takayasu arteritis was found to be more common than idiopathic inflammatory aortitis and giant cell arteritis among our 15 cases diagnosed with aortitis. All patients received medical therapy and 33% received interventional procedures, leading to 67% improvement of disease activity or related complications. This article also offers a comprehensive review of the diagnosis, management, and outcome of aortitis, supplementing the very limited literature on this disease.

Hematopoietic-to-mesenchymal transition of adipose tissue macrophages is regulated by integrin β1 and fabricated fibrin matrices

Some bona fide adult adipocytes arise de novo from a bone marrow-derived myeloid lineage. These studies further demonstrate that adipose tissue stroma contains a resident population of myeloid cells capable of adipocyte and multilineage mesenchymal differentiation. These resident myeloid cells lack hematopoietic markers and express mesenchymal and progenitor cell markers. Because bone marrow mesenchymal progenitor cells have not been shown to enter the circulation, we hypothesized that myeloid cells acquire mesenchymal differentiation capacity in adipose tissue. We fabricated a 3-dimensional fibrin matrix culture system to define the adipose differentiation potential of adipose tissue-resident myeloid subpopulations, including macrophages, granulocytes and dendritic cells. Our data show that multilineage mesenchymal potential was limited to adipose tissue macrophages, characterized by the acquisition of adipocyte, osteoblast, chondrocyte and skeletal muscle myocyte phenotypes. Fibrin hydrogel matrices stimulated macrophage loss of hematopoietic cell lineage determinants and the expression of mesenchymal and progenitor cell markers, including integrin β1. Ablation of integrin β1 in macrophages inhibited adipocyte specification. Therefore, some bona fide adipocytes are specifically derived from adipose tissue-resident macrophages via an integrin β1-dependent hematopoietic-to-mesenchymal transition, whereby they become capable of multipotent mesenchymal differentiation. The requirement for integrin β1 highlights this molecule as a potential target for controlling the production of marrow-derived adipocytes and their contribution to adipose tissue development and function.

A Dedicated Surveillance Program Improves Compliance with Endovascular Aortic Aneurysm Repair Follow-up

BACKGROUND

Current recommendations suggest lifetime follow-up for endovascular aortic aneurysm repair (EVAR) patients to avoid consequences associated with endoleak and aneurysm enlargement. Follow-up compliance has been reported between 43% and 92%, with most single-center studies citing successful follow-up surveillance at less than 60%. We investigated follow-up completeness with a defined surveillance program and subsequent secondary intervention prevalence from a single center.

METHODS

Our surveillance program notified patients of the need for follow-up imaging and surgeon review. Data were obtained from retrospective review of a prospective database, including operative and follow-up details, follow-up imaging completeness, endoleak incidence, and secondary intervention prevalence.

RESULTS

Five hundred seventeen patients received elective EVAR from 2005 to 2015. Surveillance was achieved in 425 (82.3%). Mean number of follow-up studies was 4.2 ± 2.9 and median time to first follow-up was 36 days. Four hundred forty-eight patients (86.7%) had freedom from intervention. Sixty-nine unique patients (13.3%) had 107 secondary interventions. Median time to first secondary intervention in 69 patients was 476 days. Mean number of imaging studies for secondary intervention patients was 6.1 ± 3.9, compared with mean 3.4 ± 2.3 for patients without (P < 0.001). Overall mortality was 24.6% (n = 127), including 32 deaths of unknown cause (6.2% overall) and 95 of non-EVAR-related causes (18.3%). No aneurysm-related deaths were reported.

CONCLUSIONS

Regular post-EVAR surveillance through a dedicated program resulted in a high rate of follow-up compliance, 13.3% rate of secondary intervention, and low aneurysm-related mortality. Careful lifetime surveillance remains important in long-term care following elective EVAR.

Most Patients with Abdominal Aortic Aneurysm Are Not Suitable for Endovascular Repair Using Currently Approved Bifurcated Stent-Grafts

Strict morphologic criteria must be used for patient selection to achieve durable success with endovascular aortic aneurysm repair (EVAR). The goal of this study was to assess morphologic suitability (MS) of abdominal aortic aneurysms (AAAs) for 2 currently approved bifurcated stent grafts and identify reasons for exclusion from EVAR. The authors reviewed the electronic charts of 1,795 consecutive patients who were diagnosed as having AAA between January 1999 and July 2001 at their institution. Three hundred and twenty patients had an AAA with a diameter of =5.0 cm, measured on computed tomography (CT). The records of 301 patients, 254 men, 47 women, with a mean age of 74 years were available for review, and these patients constituted the study cohort. Criteria used for MS included a proximal neck length =15 mm; neck diameter between 18 and 26 mm; neck angulation =60°; common or external iliac artery (CIA or EIA) diameters of 7–16 mm and 8–13 mm, respectively, for AneuRx (Medtronic Ave, Santa Rosa, CA) and Ancure (Guidant Cardiac and Vascular Division, Menlo Park, CA) bifurcated grafts. AAAs were suitable for AneuRx device in 14% of patients (43 of 301; 95% CI = 11–19%) and for Ancure in 5% (16 of 301; 95% CI = 3.1–9%). The main reason for exclusion was an inadequate proximal aortic neck (73%). The neck was too short in 49.5%, too wide in 64% and badly angulated in 12% of the patients. Iliac artery morphology precluded EVAR with AneuRx and Ancure devices in 52% and 80%. Both CIAs were too wide for EVAR in 43% and 77%, respectively. When iliac artery diameter =20 mm was accepted, iliac suitability for AneuRx increased from 49% to 70% and overall suitability increased from 14% to 20%. When more permissive criteria were used for MS (neck length =10 mm, neck diameter =30 mm, CIA =20), 39% of patients became candidates for EVAR. More than three fourths of the patients with an AAA =5.0 cm in size, seen in a tertiary referral center, are morphologically not suitable for EVAR using 2 currently approved bifurcated endografts. The main reasons for exclusion are a short or wide proximal aortic neck. Considerable changes in size of the devices and in proximal attachment techniques have to occur before most AAAs will be suitable for EVAR.

Stenting of the Renal Artery to Improve Renal Function Prior to Thoracoabdominal Aneurysm Repair

Purpose:

To report the successful staged treatment of a patient with a thoracoabdominal aortic aneurysm (TAA), who presented with renal insufficiency attributable to renal artery stenosis.

Methods and Results:

A 66-year-old woman with a 6-cm Crawford type IV TAA presented with uncontrolled hypertension (240/130 mmHg), worsening congestive heart failure, and progressive renal insufficiency (serum creatinine 3.8 mg/dL) caused by renal artery stenosis to a solitary functioning kidney. Renal artery stenting restored normal renal and pulmonary function, and elective TAA repair 6 weeks after percutaneous stenting was uneventful. Restenosis (50% diameter reduction) in the renal artery was found 10 months later and treated with repeat dilation. Secondary patency was maintained at follow-up 21 months after redilation.

Conclusions:

It appears feasible to use preliminary renal artery stenting to reduce operative risk in TAA surgical candidates with renal insufficiency secondary to renal artery stenosis.

Endovascular Management of Unusual Aneurysms of the Axillary and Subclavian Arteries

Purpose:

Aneurysms of the upper extremity arteries are uncommon and may be difficult to manage with standard surgical techniques. We report the exclusion of three axillary-subclavian aneurysms with covered stents.

Methods and Results:

Palmaz stents were covered with either polytetrafluoroethylene (2 cases) or brachial vein and deployed to exclude pseudoaneurysms in 1 axillary (ruptured) and 2 left subclavian arteries. Two of the patients had advanced cancer and died within 52 days and 3 months of treatment, but their aneurysms were occluded at the time of their death. The repair in the third patient is patent at 9 months.

Conclusions:

Endovascular exclusion of axillary and subclavian aneurysms with covered stents may offer a useful alternative to operative repair, particularly in patients with significant comorbidities.

De novo generation of adipocytes from circulating progenitor cells in mouse and human adipose tissue

White adipocytes in adults are typically derived from tissue resident mesenchymal progenitors. The recent identification of de novo production of adipocytes from bone marrow progenitor-derived cells in mice challenges this paradigm and indicates an alternative lineage specification that adipocytes exist. We hypothesized that alternative lineage specification of white adipocytes is also present in human adipose tissue. Bone marrow from transgenic mice in which luciferase expression is governed by the adipocyte-restricted adiponectin gene promoter was adoptively transferred to wild-type recipient mice. Light emission was quantitated in recipients by in vivo imaging and direct enzyme assay. Adipocytes were also obtained from human recipients of hematopoietic stem cell transplantation. DNA was isolated, and microsatellite polymorphisms were exploited to quantify donor/recipient chimerism. Luciferase emission was detected from major fat depots of transplanted mice. No light emission was observed from intestines, liver, or lungs. Up to 35% of adipocytes in humans were generated from donor marrow cells in the absence of cell fusion. Nontransplanted mice and stromal-vascular fraction samples were used as negative and positive controls for the mouse and human experiments, respectively. This study provides evidence for a nontissue resident origin of an adipocyte subpopulation in both mice and humans.

Radiation exposure to comforters and carers during paediatric molecular radiotherapy

BACKGROUND

To show whether the incidental radiation exposure received by comforters and carers of children undergoing molecular radiotherapy was kept as low as reasonably achievable and was within English national dose constraints.

PROCEDURE

The radiation exposure of adult comforters and carers was routinely monitored with a whole body personal dose meter while the child was in hospital. Data were collected on iodine-131 meta-iodobenzylguanidine (¹³¹ I-mIBG), lutetium-177 DOTATATE (¹⁷⁷ Lu-DOTATATE), and iodine-131 sodium iodide (¹³¹ I-NaI) treatments.

RESULTS

Data were available for 50 treatments with high-administered activity double-infusion ¹³¹ I-mIBG and 12 single administrations; 15 ¹⁷⁷ Lu-DOTATATE treatments and 28 ¹³¹ I-NaI administrations. The median age was 7 years (1-18). The median administered activity of: ¹³¹ I-mIBG was 16.2 GBq (6.8-59 GBq) for double infusion patients and 8.1 GBq (5.26-16.25 GBq) for single administrations; ¹⁷⁷ Lu-DOTATATE was 7.2 GBq (2.5-7.5 GBq); and ¹³¹ I-NaI was 3 GBq for thyroid remnant ablation and 5.5 GBq for cancer therapy. The median number of comforters and carers for all administrations was 2 (range 1-9). The median exposure values for comforters and carers for high-administered activity ¹³¹ I-mIBG administrations was 302 µSv (0-5282 µSv); for single fraction ¹³¹ I-mIBG 163 µSv (3-3104 µSv); ¹⁷⁷ Lu-DOTATATE 6 µSv (1-79 µSv); and ¹³¹ I-NaI 37 µSv (0-274 µSv). Only one of the comforters and carers exceeded the dose constraint of 5 mSv.

CONCLUSIONS

Doses to comforters and carers were in all but one case within the dose constraint nationally recommended by the Health Protection Agency, now part of Public Health England. New evidence is presented which show that comforter and carer radiation exposure levels from paediatric molecular radiotherapy in routine clinical practice are acceptably low. Pediatr Blood Cancer 2015;62:235-239. © 2014 Wiley Periodicals, Inc.

Obesity-related pulmonary arterial hypertension in rats correlates with increased circulating inflammatory cytokines and lipids and with oxidant damage in the arterial wall but not with hypoxia

Obesity is causally linked to a number of comorbidities, including cardiovascular disease, diabetes, renal dysfunction, and cancer. Obesity has also been linked to pulmonary disorders, including pulmonary arterial hypertension (PAH). It was long believed that obesity-related PAH was the result of hypoventilation and hypoxia due to the increased mechanical load of excess body fat. However, in recent years it has been proposed that the metabolic and inflammatory disturbances of obesity may also play a role in the development of PAH. To determine whether PAH develops in obese rats in the absence of hypoxia, we assessed pulmonary hemodynamics and pulmonary artery (PA) structure in the diet-resistant/diet-induced obesity (DR/DIO) and Zucker lean/fatty rat models. We found that high-fat feeding (DR/DIO) or overfeeding (Zucker) elicited PA remodeling, neomuscularization of distal arterioles, and elevated PA pressure, accompanied by right ventricular (RV) hypertrophy. PA thickening and distal neomuscularization were also observed in DIO rats on a low-fat diet. No evidence of hypoventilation or chronic hypoxia was detected in either model, nor was there a correlation between blood glucose or insulin levels and PAH. However, circulating inflammatory cytokine levels were increased with high-fat feeding or calorie overload, and hyperlipidemia and oxidant damage in the PA wall correlated with PAH in the DR/DIO model. We conclude that hyperlipidemia and peripheral inflammation correlate with the development of PAH in obese subjects. Obesity-related inflammation may predispose to PAH even in the absence of hypoxia.

Maternal endocrine adaptation throughout pregnancy to nutrient manipulation: consequences for sexually dimorphic programming of thyroid hormones and development of their progeny

Maternal nutrient restriction during critical windows of fetal development alters postnatal growth, often in a sexually dimorphic manner. Intrauterine growth restriction is frequently characterized by accelerated growth and increased adiposity in later life. Thyroid hormones are implicated as part of the mechanism involved in this scenario via their actions within the hypothalamic-pituitary-thyroid axis. We fed high (H = 240%) and low (L = 70%) levels of recommended daily crude protein intake during the first and second trimesters of gestation to beef heifers to investigate effects to their progeny's plasma concentrations of free and total triiodothyronine (FT3 and TT3) and thyroxine (FT4 and TT4) from birth until weaning at 191 days of age (n = 68). The study design was a two-by-two factorial. For male progeny, exposure to maternal diets low in protein during the first trimester of gestation resulted in greater FT4 at birth (P < 0.05) which was subsequent to lower concentrations of leptin in maternal plasma at 271 days of gestation compared with their high-protein-exposed counterparts. These same animals went on to have greater milk intake during the latter half of the lactation period (P < 0.05) and exhibited faster rates of average daily gain (ADG) relative to birth weight during this time (P < 0.05). For all progeny, independent of sex, exposure to low-protein maternal diets during the second trimester of gestation resulted in greater FT3 relative to TT3 at birth. Because FT3 at birth and 29 days was positively associated with ADG (P < 0.05) and ADG relative to birth weight (P < 0.05), it is proposed that FT3 plays an integral role in catch-up growth in the bovine as per other species. Protein intake during the first and second trimesters of gestation has a sexually dimorphic effect on progeny plasma thyroid hormone concentrations, and these changes are associated with altered milk intake and postnatal growth pathway.

Open versus endovascular revascularization for chronic mesenteric ischemia: risk-stratified outcomes

OBJECTIVE

Outcomes of open (OR) and endovascular revascularization (ER) for chronic mesenteric ischemia (CMI) were analyzed with respect to clinical risk stratification.

METHODS

The data of 229 consecutive patients treated for CMI with OR (146 patients/265 vessels) or ER (83 patients/105 vessels) between 1991 and 2005 were reviewed. Patients were classified as low-risk or high-risk using standard scoring systems. End points were mortality and morbidity, recurrence-free survival, and patency rates. A subset analysis compared 111 patients (208 vessels) who had OR with 58 patients (76 vessels) who had stenting.

RESULTS

The ER patients were significantly older (71 +/- 15 vs 65 +/- 11 years; P < .05), had higher risk (58% vs 31%), and fewer vessels revascularized (1.3 +/- 0.5 vs 1.8 +/- 0.4). Four (2.7%) procedurally related deaths occurred in the OR and two (2.4%) in the ER group (P = NS). Mortality was higher for high-risk patients (OR, 6.7% vs 0.9%; ER, 4.8% vs 0%; P < .05), but differences were not significant among low-risk or high-risk OR vs ER patients. OR patients had more complications (36% vs 18%; P < .001) and longer hospitalization (12 +/- 8 vs 3 +/- 5 days; P < .001). At 5 years, OR had improved (P < .05) recurrence-free survival (89% +/- 4% vs 51% +/- 9%), and primary (88% +/- 3% vs 41% +/- 9%) and secondary patency rates (97% +/- 2% vs 88% +/- 4%). More restenoses (hazard ratio [HR], 5.1; 95% confidence interval [CI], 2.4-10.2), recurrences (HR, 6.7; 95% CI, 3.3-13.8), and reinterventions occurred in the ER group (HR, 4.3; 95% CI, 1.9-9.7). At last follow-up, significant symptom improvement was noted in 137 OR (96%) and 72 ER patients (92%, P = NS). In the subset analysis of patients having first-time operations vs stenting, OR resulted in improved (P < .05) recurrence-free survival (91% +/- 3% vs 56% +/- 8% at 5 years) and better primary and secondary patency rates (93% +/- 2% and 98% +/- 1% vs 52% +/- 8% and 93% +/- 4% at 3 years).

CONCLUSION

OR has similar mortality but higher morbidity and longer hospitalization than ER in low-risk or high-risk patients with CMI. Both treatments effectively improved symptoms, but restenosis, recurrent symptoms, and reinterventions were more likely in ER patients. These findings may guide treatment selection and counseling of low-risk and high-risk CMI patients undergoing OR or ER procedures.

Large thoracic aortic aneurysm and dissection with rare complication

Thoracic aortic aneurysms can be found incidentally, however, patients can also present with acute dissection and or rupture that can be fatal. Symptoms that might indicate dissection include chest and back pain as well as lightheadedness. The diagnosis can be made with imaging studies such as computed tomography or magnetic resonance angiogram and sometimes transesophageal echocardiogram. Management is based on the aneurysmal size, location, extension, and the presence of complications. Although smaller localized and slow growing aneurysms can be monitored, larger and or complicated ones may warrant immediate repair. Less-common complications include compression over anatomic structures in the vicinity including vessels and the mediastinum. We report a unique case of a 71-year-old man who presented with a very large thoracic aortic aneurysm with dissection causing compression over the brachiocephalic veins and the mediastinum leading to facial and upper extremity swelling, dysphagia, and cough. This case represents a rare but significant complication of thoracic aortic aneurysm and emphasizes the challenges of its management.

Inhibition of phosphatidylinositol 3-kinase/Akt signaling attenuates hypoxia-induced pulmonary artery remodeling and suppresses CREB depletion in arterial smooth muscle cells

Hypoxia-induced pulmonary hypertension is characterized by progressive remodeling of the pulmonary artery (PA) system and loss of the transcription factor, cAMP response element binding protein (CREB) in PA smooth muscle cells (SMCs). Previous in vitro studies suggested that platelet-derived growth factor, a mitogen produced in the hypoxic arterial wall, elicits loss of CREB in medial SMCs via the PI3K/Akt pathway. These events trigger switching of SMCs from a quiescent, contractile phenotype to a proliferative, migratory, dedifferentiated, and synthetic phenotype, which contributes to PA thickening. Here, we investigated whether inhibition of PI3K or Akt could attenuate arterial remodeling in the lung and prevent CREB loss in PA medial SMCs in rats subjected to chronic hypoxia. Inhibition of either enzyme-blunted hypoxia-induced PA remodeling and SMC CREB depletion and diminished SMC proliferation and collagen deposition. Inhibition of Akt, but not PI3K, suppressed muscularization of distal arterioles and blunted right ventricular hypertrophy. Interestingly, mean PA pressure was elevated equally by hypoxia in untreated and inhibitor-treated groups but was normalized acutely by the Rho kinase inhibitor, Fasudil. We conclude that PI3K and Akt inhibitors can attenuate hypoxia-induced PA remodeling and SMC CREB depletion but fail to block the development of pulmonary hypertension because of their inability to repress Rho kinase-mediated vasoconstriction.

Peripheral artery disease is an independent predictor of mortality after implantable cardioverter-defibrillator implantation in patients with severe left ventricular dysfunction

The impact of peripheral artery disease (PAD) on survival in implantable cardioverter defibrillator (ICD) patients is poorly understood. Thus, we assessed the risk of PAD in our adult ICD patients with left ventricular dysfunction (ejection fraction [EF] ≤35%). Survival was estimated with Kaplan-Meier method and compared by the log-rank test; a Cox proportional hazards model assessed the effects of clinical variables on survival. Average age and EF of 1399 patients were 67.0 ± 12.1 years and 23.8% ± 7.2%, respectively. The ICD patients with PAD had significantly worse survival than those without (unadjusted P < .0001). The multivariate predictors of survival at implant were (hazard ratio, HR [95% confidence interval]) age (HR 1.05 [1.04-1.07] P < .0001), PAD (HR 2.07 [1.53-2.80] P < .0001), class III/IV heart failure (HR 1.36 [1.06-1.76] P = .016), creatinine 1.4-2.0 mg/dL (HR 1.36 [1.05-1.76] P = .019), and creatinine ≥2.0 mg/dL (HR 2.01 [1.42-2.85] P < .0001). The PAD is an independent predictor of mortality and should be considered in the preimplant risk assessment.

Concurrent Takayasu arteritis with common variable immunodeficiency and moyamoya disease

Takayasu arteritis is a rare, chronic form of large vessel vasculitis that characteristically involves the aorta and its branches. Its origin and disease process are currently unknown, although T lymphocytes and, most recently, B cells are thought to play a role. Common variable immunodeficiency (CVID) is a collection of heterogeneous disorders resulting in an antibody deficiency and recurrent infections, and is the most common symptomatic primary immunodeficiency disorder. This report presents a unique case of possible Takayasu arteritis with a history of CVID in a young man admitted with multiple cerebrovascular accidents. Takayasu arteritis may serve as the main cause of this presentation. The rarity of this case is further accentuated by the presence of moyamoya disease. Finally, the possible disease process and novel treatment of Takayasu arteritis is discussed briefly.

MAP kinase kinase kinase-2 (MEKK2) regulates hypertrophic remodeling of the right ventricle in hypoxia-induced pulmonary hypertension

Pulmonary hypertension (PH) results in pressure overload of the right ventricle (RV) of the heart, initiating pathological RV remodeling and ultimately leading to right heart failure. Substantial research indicates that signaling through the MAPK superfamily mediates pathological cardiac remodeling. These considerations led us to test the hypothesis that the regulatory protein MAPKKK-2 (MEKK2) contributes to RV hypertrophy in hypoxia-induced PH. Transgenic mice with global knockout of MEKK2 (MEKK2(-/-) mice) and age-matched wild-type (WT) mice were exposed to chronic hypobaric hypoxia (10% O(2), 6 wk) and compared with animals under normoxia. Exposure to chronic hypoxia induced PH in WT and MEKK2(-/-) mice. In response to PH, WT mice showed RV hypertrophy, demonstrated as increased ratio of RV weight to body weight, increased RV wall thickness at diastole, and increased cardiac myocyte size compared with normoxic control animals. In contrast, each of these measures of RV hypertrophy seen in WT mice after chronic hypoxia was attenuated in MEKK2(-/-) mice. Furthermore, chronic hypoxia elicited altered programs of hypertrophic and inflammatory gene expression consistent with pathological RV remodeling in WT mice; MEKK2 deletion selectively inhibited inflammatory gene expression compared with WT mice. The actions of MEKK2 were mediated in part through regulation of the abundance and phosphorylation of its effector, ERK5. In conclusion, signaling by MEKK2 contributes to RV hypertrophy and altered myocardial inflammatory gene expression in response to hypoxia-induced PH. Therapies targeting MEKK2 may protect the myocardium from hypertrophy and pathological remodeling in human PH.

Protein intake during gestation affects postnatal bovine skeletal muscle growth and relative expression of IGF1, IGF1R, IGF2 and IGF2R

Expression of insulin-like growth factor (IGF)1 and IGF2 and their receptor (IGF1R and IGF2R) mRNA in fetal skeletal muscle are changed by variations in maternal nutrient intake. The persistence of these effects into postnatal life and their association with phenotype in beef cattle is unknown. Here we report that the cross-sectional areas of longissimus dorsi and semitendinosus (ST) muscles were greater for mature male progeny born to heifers fed low protein diets (70% vs. 240% of recommended) during the first trimester. In ST, this was accompanied by greater IGF1, IGF2 and IGF2R mRNA at 680 d. Females exposed to low protein diets during the first trimester had decreased IGF2 mRNA in ST at 680 d, however this did not result in an effect to phenotype. Exposure to low protein diets during the second trimester increased IGF1R mRNA in ST of all progeny at 680 d. Changes to expression of IGF genes in progeny skeletal muscle resulting from variations to maternal protein intake during gestation may have permanent and sex-specific effect on postnatal skeletal muscle growth.

Dietary manipulation of Bos indicus x heifers during gestation affects the reproductive development of their heifer calves

The effect of nutrition during the first and second trimesters of pregnancy in composite beef heifers on reproductive parameters of their female calves was determined in the present study. At artificial insemination, heifers were assigned to one of four treatment groups (i.e. HH, HL, LowH and LL) depending on the level of crude protein intake (H = high; L = low) for first and second trimesters of pregnancy. Gonadotrophin concentrations and ovarian parameters were measured in their female calves at 5 and 23 months of age. Crude protein intake was positively associated with dam plasma urea (P < 0.001). The density of healthy follicles in heifers at the time of death was negatively correlated with dam plasma urea at Day 179 (P = 0.009). Heifers from LowH dams had a smaller-sized prepubertal largest ovarian follicle (P = 0.03) and lower densities of primordial and primary follicles (P = 0.02) and healthy antral follicles (P = 0.009) when they were killed. There was a positive correlation between plasma FSH concentrations at 5 and 23 months of age (P = 0.02), as well as between the sizes of the largest ovarian follicles at 6 and 23 months of age (P = 0.01). In conclusion, the reproductive development of heifers may be affected by prenatal nutrition during early and mid-gestation.

Open and endovascular revascularization for chronic mesenteric ischemia: tabular review of the literature

Chronic mesenteric ischemia is an uncommon disease in vascular surgery practice worldwide. Open revascularization remains the best treatment for low-risk patients due to durability and efficacy. Endovascular revascularization for chronic mesenteric ischemia was primarily indicated for elderly and higher-risk patients, but this has changed over the past 10 years due to development of more precise devices and lower morbidity and mortality rates despite the higher recurrence and restenosis rates. Our purpose was to summarize the data on endovascular and open revascularization for chronic mesenteric ischemia in a schematic tabular presentation.

Dietary protein during gestation affects circulating indicators of placental function and fetal development in heifers

The influences of nutritional protein during the first and second trimesters of pregnancy on placental hormones and fetal growth were determined in composite beef heifers. At artificial insemination, heifers were stratified by weight within each composite genotype into 4 treatment groups: High High (HH=1.4kg crude protein (CP)/day for first and second trimesters of gestation; n=16), High Low (HL=1.4kg CP/day for first trimester and 0.4kg CP/day for second trimester; n=19), Low High (LH=0.4kg CP/day for first trimester and 1.4kg CP/day for second trimester; n=17) or Low Low (LL=0.4kg CP/day for first and second trimesters; n=19). Maternal plasma bovine pregnancy associated glycoprotein (bPAG) and progesterone (P4) were determined at gestation day (gd) 28, 82, 179 and 271 (mean gestation length 286 days) in addition to P4 at term. Estrone sulphate (ES) and bovine placental lactogen (bPL) concentrations were measured at gd 124, 179, 236 and 271 and at term in addition to ES at gd 82. Low dietary protein increased placental function as indicated by increased bPAG (P<0.001) and ES (P=0.02) concentrations in first trimester and increased bPL concentrations (P=0.01) in the second trimester of gestation. In the third trimester, when dietary treatment had ceased, placental function was no longer associated with previous dietary treatments. Dam genotype affected placental function as measured by bPL (P<0.001) and ES concentrations (P=0.02). Calf gender, heifer age and maternal insulin-like growth factor (IGF)-I, -II and leptin did not affect hormonal indicators or circulating markers of placental function. Enhanced placental function during the third trimester, as measured by ES, was associated with increased calf birth weight (P=0.003).

Critical limb ischemia: medical and surgical management

Abstract

Chronic critical limb ischemia (CLI), defined as > 2 weeks of rest pain, ulcers, or tissue loss attributed to arterial occlusive disease, is associated with great loss of both limb and life. Therapeutic goals in treating patients with CLI include reducing cardiovascular risk factors, relieving ischemic pain, healing ulcers, preventing major amputation, improving quality of life and increasing survival. These aims may be achieved through medical therapy, revascularization, or amputation. Medical therapy includes administration of analgesics, local wound care and pressure relief, treatment of infection, and aggressive therapy to modify atherosclerotic risk factors. For patients who are not candidates for revascularization, and who are unwilling or unable to undergo amputation, treatments such as intermittent pneumatic compression or spinal cord stimulation may offer symptom relief and promote wound healing. Revascularization offers the best option for limb salvage. The decision to perform surgery, endovascular therapy, or a combination of the two modalities (‘hybrid’ therapy) must be individualized. Patients who are relatively fit and able to withstand the rigors of an open procedure may benefit from the long-term durability of surgical repair. In contrast, frail patients with a limited life expectancy may experience better outcomes with endovascular reconstruction. Hybrid therapy is an attractive option for patients with limited autologous conduit, as it permits complete revascularization with a less extensive procedure, shorter duration of operation, and decreased risk of peri-operative complications. Amputation should be considered for patients who are non-ambulatory, demented, or unfit to undergo revascularization.

A technique of extending small-bowel mesentery for ileal pouch-anal anastomosis: report of a case

One of the keys to success in proctocolectomy with ileal pouch-anal anastomosis is obtaining adequate mesenteric length to allow the pouch to reach the anorectum without tension. A multitude of techniques have been described in the literature to gain mesenteric length; however, in most cases these techniques only allow for the correction of a small deficit in the mesenteric length. We encountered a case in which the small-bowel mesentery was severely foreshortened because of a previous small-bowel volvulus just proximal to the loop ileostomy during recovery from the initial stage of his ileal pouch procedure. In this case, the deficit in length required an interposition vein graft to the superior mesenteric artery to facilitate adequate mesenteric length and allow completion of the ileal pouch-anal anastomosis. We report this technique to add another method of mesenteric lengthening to the armamentarium of surgeons performing ileal pouch-anal anastomoses. This technique should only be used as a last resort.

Vascular abnormalities in patients with neurofibromatosis syndrome type I: clinical spectrum, management, and results

PURPOSE

Neurofibromatosis type I (NF-I) is an autosomal dominant disorder affecting one in 3000 individuals. Vascular abnormalities are a well-recognized manifestation of NF-I. The purpose of this study is to review the spectrum, management, and clinical outcome of patients with vascular abnormalities and NF-I.

METHODS

We retrospectively reviewed 31 patients (15 males, 16 females) with clinical NF-I and vascular abnormalities identified from imaging or operative findings between 1976 and 2005.

RESULTS

The diagnosis of NF-I was made at a mean age of 11 +/- 10 years with vascular lesions identified at a mean age of 38 +/- 16 years. There were 76 vascular abnormalities, including 38 aneurysms, 20 arterial stenoses, 5 arteriovenous malformations (AVM), 5 arteries compressed or invaded by neural tumors, and 6 abnormalities of the heart valves. Arterial lesions were located in the aorta (n = 17) and in the renal (n = 12), mesenteric (n = 12), carotid-vertebral (n = 10), intracerebral (n = 4), and subclavian-axillary and iliofemoral arteries (3 each). Interventions were required in 23 patients (74%); 15 underwent 24 arterial reconstructions, including 9 renal, 8 aortic, 4 mesenteric, 2 carotid, and 1 femoral. The other eight patients had excision of AVM in three, vessel ligation in two, and clipping of cerebral aneurysms, coil embolization of hepatic aneurysms, and left thoracotomy in one patient each. One patient died of ruptured abdominal aortic aneurysm. Six patients (26%) had postoperative complications, including pneumonia in two, and stroke, acalculous cholecystitis, brachial plexopathy and chylothorax in one patient each. The median follow up was 4.1 years (range, 6 months to 20 years). Late vascular problems developed in three patients, including graft stenoses in two and rupture of another aortic aneurysm in one. Freedom from graft-related complications was 83% at 10 years. Patient survival at 10 years was 77%, less than the 86% expected survival for the general population (P < .001).

CONCLUSION

Patients with NF-I have a wide spectrum of vascular abnormalities, most notably aneurysms or stenoses of the aortic, renal, and mesenteric circulation. Operative treatment of symptomatic patients with vascular lesions or large aneurysms is safe, effective, and durable.

Early complications and long-term outcome after open surgical treatment of popliteal artery aneurysms: is exclusion with saphenous vein bypass still the gold standard?

BACKGROUND

Popliteal artery aneurysms (PAAs) are rare, but thromboembolic complications may result in limb loss. To define complications and outcomes after open surgical repairs, we reviewed our experience.

METHODS

Clinical data of patients with PAA seen between 1985 and 2004 at Mayo Clinic, Rochester, Minnesota, were reviewed and outcomes in 289 patients with open revascularization were analyzed. Kaplan-Meier method with log-rank tests, chi(2), and Wilcoxon rank sum tests were used for analysis.

RESULTS

A total of 358 PAAs were treated in 289 patients, consisting of 281 (97%) men and eight (3%) women. There were 133 (46%) unilateral and 156 (54%) bilateral PAAs with a mean diameter of 2.9 cm (range, 1.5 to 9 cm). Abdominal aortic aneurysm (AAA) was more frequent with bilateral than unilateral PAAs (65% [101/156] vs 42% [56/133] P = .001). There were 144 (40%) asymptomatic limbs (group 1), 140 (39%) had chronic symptoms (group 2), and 74 (21%) had acute ischemia (group 3). Great saphenous vein (GSV) was used in 242 limbs (68%), polytetrafluoroethylene (PTFE) in 94 (26%), and other types of graft in 22 (6%). Early mortality was 1% (3/358), all in group 3 (4% [3/74]). Six of seven patients with perioperative myocardial infarctions belonged to group 3 (8%). The 30-day graft thrombosis rate was 4%, with 1% in group 1 (1/144), 4% in group 2 (5/140), and 9% in group 3 (7/74). All six early amputations (8%) were in group 3, five with failed bypass (4 PTFE, 1 GSV). Mean follow-up was 4.2 years (range, 1 month to 20.7 years). The 5-year primary and secondary patency rates were 76% and 87%, respectively, higher with GSVs (85% and 94%) than PTFE (50% and 63%, P < .05). Seven recurrent PAAs (2%) required reintervention. The 5-year freedom from reintervention was 100% after endoaneurysmorrhaphy vs 97% after ligations (P = .03). Five-year limb salvage rate was 97% (85% in group 3). There was no limb loss in group 1 and none in group 2 with GSV. In group 3, preoperative thrombolysis reduced the amputation rate in class II patients with marginally threatened limbs (96% vs 69%, P = .02).

CONCLUSION

Acute presentation of PAA continues to carry high mortality and cardiac morbidity; although preoperative thrombolysis appears to improve results, the 8% early and 15% late amputation rates remain ominous. Early elective repair is recommended because these patients had no surgical mortality, a low rate of complications, and asymptomatic patients had no limb loss at 5 years. GSV and endoaneurysmorrhaphy continues to be the gold standard for open repair of PAA.