Outcomes of completion imaging for lower extremity bypass in the Vascular Quality Initiative.

OBJECTIVE: The objective of this study was to determine the association of intraoperative completion imaging (CI) for lower extremity vein bypass to a below-knee target with primary patency in the Vascular Quality Initiative. METHODS: The Vascular Quality Initiative database was queried from January 2003 to October 2013 for lower extremity bypass (LEB) procedures that were elective, had an indication of occlusive disease, used a single-segment greater saphenous vein conduit, and had a below-knee target. LEBs with inflow arteries above the knee and below the knee were included. LEBs with concomitant endovascular procedures were excluded. CI was defined as completion angiography, completion duplex ultrasound, or both. The end points were primary patency at discharge and at 1 year. Multivariable analysis was performed controlling for patient demographics, comorbidities, bypass characteristics, and center. RESULTS: Of 14,284 LEBs that were performed during the study period, 3147 satisfied the inclusion and exclusion criteria. Of 1457 (46%) that underwent CI, 287 (20%) underwent duplex ultrasound, 1116 (77%) underwent angiography, and 54 (3.7%) underwent both duplex ultrasound and angiography. There were more patients in the CI group with a history of smoking and a bypass graft crossing the knee. There was no difference in primary patency at discharge between the two groups (CI, 93.2% vs no CI, 93.8%; P = .52). Of the patients who underwent CI, the discharge primary patency was 95.1% for completion duplex ultrasound vs 92.8% for completion angiography (P = .17). On multivariable analysis, there was no significant association of CI with discharge primary patency (P = .69). The 1-year primary patency was 63% in the CI group vs 68% in the no CI group (P = .051). The 1-year primary patency was 60% for the duplex ultrasound group vs 65% for the angiography group (P = .61). On multivariable analysis, there was no significant association of CI with 1-year primary patency (P = .69). CONCLUSIONS: In electively performed LEBs using single-segment saphenous vein to a below-knee target artery for occlusive disease, CI does not influence primary graft patency at discharge or at 1 year.

Bilateral cervical ribs causing cerebellar stroke and arterial thoracic outlet syndrome: a case report and review of the literature.

Stroke is an exceedingly rare presentation of arterial thoracic outlet syndrome (aTOS). This report describes a case of cerebellar stroke secondary to aTOS and reviews the literature. A 56-year-old woman with no previous history of stroke or arm ischemia presented with vertigo. Computed tomography (CT) and magnetic resonance imaging confirmed a left cerebellar ischemic stroke. She subsequently developed ischemia of her left arm, which was treated by a thromboembolectomy. CT angiography revealed bilateral cervical ribs along with bilateral subclavian artery aneurysms. Staged resection of the cervical ribs and reconstruction of the subclavian arteries were performed. Symptomatic arterial thoracic outlet syndrome most commonly presents as arm ischemia because of embolization of intramural clot from a subclavian artery aneurysm or because of thrombosis of the subclavian artery aneurysm itself. In rare cases, the clot can propagate retrograde, resulting in stroke. In young patients presenting with ischemic stroke, arterial thoracic outlet syndrome should be considered as part of the differential diagnosis.

Use of completion imaging during infrainguinal bypass in the Vascular Quality Initiative.

OBJECTIVE: The purpose of this study was to examine the practice patterns of intraoperative completion imaging (CI) for lower extremity bypass (LEB) in the Vascular Quality Initiative (VQI). METHODS: A retrospective review of all LEB procedures in the VQI database from January 2003 to October 2013 was performed. Regions with fewer than 200 LEB procedures were excluded from the regional analysis. The modality of CI was defined as duplex ultrasound, angiography, or both. RESULTS: A total of 14,140 LEBs were captured, with the rate of CI being 43%. After exclusion of three regions for insufficient volume (<200 LEBs), 13,945 LEB operations across 13 regions were available for regional analysis. Use of any type of intraoperative CI varied across regions from a low of 8% to a high of 70%, with angiography being performed most frequently. When CI was performed, the type of imaging modality varied between regions from a high of 99% for angiography to a high of 75% for duplex ultrasound. CI was more common in male patients (44% of male patients vs 42% of female patients; P = .032), diabetics (44% of diabetic patients vs 42% of nondiabetic patients; P = .026), and patients with coronary artery disease (45% of patients with coronary artery disease vs 42% of patients with no coronary artery disease; P = .0015). CI was performed less frequently in LEB using single-segment great saphenous vein vs LEB using lesser saphenous, arm, or composite vein (48% vs 57%; P < .0001). CI was used in 51% of LEBs with a tibial or pedal target vessel vs 38% of LEBs with a more proximal target vessel (P < .0001). Patients with an indication of critical limb ischemia underwent CI in 45% of LEBs vs 39% with an indication other than critical limb ischemia (P < .0001). CONCLUSIONS: Within the VQI database, considerable practice pattern variation exists in the use of CI. Currently, CI is most commonly employed for patients with critical limb ischemia, infrageniculate target vessel, and disadvantaged venous conduit. Further study is required to standardize and to define the appropriate use of CI for LEBs.

Aortic morphologic findings after thoracic endovascular aortic repair for type B aortic dissection.

IMPORTANCE: Thoracic endovascular aortic repair (TEVAR) is used in the treatment of type B aortic dissections. Information related to aortic morphologic findings and the condition of the abdominal aorta after TEVAR is limited. OBJECTIVE: To analyze aortic morphologic findings after TEVAR for type B aortic dissections. DESIGN, SETTING, AND PARTICIPANTS: After a retrospective database review, the data for 30 patients who underwent TEVAR from January 1, 2007, through December 31, 2013, for type B aortic dissection were analyzed. Imaging software was used to calculate aortic diameters and volumes of the aorta on computed tomography (CT) or magnetic resonance imaging (MRI). Mean follow-up was 14.4 months. INTERVENTIONS: We performed TEVAR to cover proximal thoracic aorta tears in patients who underwent acute or chronic type B aortic dissections. MAIN OUTCOMES AND MEASURES: Aortic morphologic findings of pre-TEVAR CT or MRI were compared with the most recent findings of post-TEVAR CT or MRI. Frequency of thoracic false lumen thrombosis (FLT) and false lumen patency (FLP) was determined and the effect on post-TEVAR aortic morphologic findings analyzed. RESULTS: Mean (SD) TEVAR increased true lumen diameter (19.50 [6.92] mm to 31.19 [5.36] mm, P < .001) and volume (77.92 [41.70] mL to 166.95 [69.69] mL, P < .001) and decreased false lumen diameter (29.77 [12.55] mm to 21.92 [12.05] mm, P = .001) on post-TEVAR CT or MRI when compared with pre-TEVAR scans. Seventy percent of patients experienced thoracic FLT; 30% had FLP. True lumen volume expansion and false lumen volume regression occurred in patients with FLT (82.07 [46.95] mm to 180.55 [77.99] mm, P < .001 and 161.84 [106.36] mm to 115.76 [140.77] mm, P = .002, respectively) and FLP (68.23 [21.43] mm to 128.22 [21.46] mm, P < .001 and 238.64 [174.00] mm to 198.93 [120.46] mm, P = .04, respectively). Patients with FLT had increased true lumen diameter (15.67 [6.43] mm to 26.13 [7.62] mm, P < .001) and volume (54.86 [30.52] mL to 88.08 [41.07] mL, P = .001) in the abdominal aorta after TEVAR, with no change in total abdominal aortic volume (161.94 [70.12] mL vs 160.36 [82.11] mL, P = .90). Total abdominal aortic volume significantly increased in patients with thoracic FLP (187.24 [89.88] mL to 221.41 [82.64] mL, P = .02). CONCLUSIONS AND RELEVANCE: Favorable aortic remodeling of the thoracic aorta occurs after TEVAR for type B aortic dissections in patients with thoracic FLT and FLP. However, failure to achieve thrombosis of the thoracic false lumen negatively influences aortic morphologic findings of the contiguous abdominal aorta.

A novel cardioprotective agent in cardiac transplantation: metformin activation of AMP-activated protein kinase decreases acute ischemia-reperfusion injury and chronic rejection.

The main cause of mortality after the first year from cardiac transplantation is cardiac allograft vasculopathy (CAV), which leads to chronic rejection of the heart. To improve long-term outcomes in cardiac transplantation, treatments to prevent or diminish CAV are actively being researched. Ischemia-reperfusion (I-R) injury has been shown to be the strongest alloantigen-independent factor in the development of CAV. Here, we investigate the use of metformin in murine cardiac transplantation models as a novel cardioprotective agent to limit acute I-R injury and subsequent chronic rejection. We show that metformin treatment activates AMP-activated kinase (AMPK) in vitro and in vivo. In the acute transplantation model, metformin activation of AMPK resulted in significantly decreased apoptosis in cardiac allografts on postoperative day (POD) 1 and 8. In the chronic transplantation model, metformin pretreatment of allografts led to significantly improved graft function and significantly decreased CAV, as measured on POD 52. Taken together, our results in the acute and chronic rejection studies suggest a potential cardioprotective mechanism for metformin; we demonstrate a correlation between metformin-induced decrease in acute I-R injury and metformin-related decrease in chronic rejection. Thus, one of the ways by which metformin and AMPK activation may protect the transplanted heart from chronic rejection is by decreasing initial I-R injury inherent in donor organ preservation and implantation. Our findings suggest novel therapeutic strategies for minimizing chronic cardiac rejection via the use of metformin- and AMPK-mediated pathways to suppress acute I-R injury.

Cytokine amplification by respiratory syncytial virus infection in human nasal epithelial cells.

OBJECTIVES: Respiratory syncytial virus (RSV) is an important cause of upper respiratory infections and is known to play a causal role in the pathogenesis of rhinitis, sinusitis, acute otitis media, and pneumonia. RSV appears to prime the respiratory tract to secondary inciting events, such as bacterial or antigen challenges. To study the proinflammatory priming effects of RSV infection, cytokine expression was measured in well-differentiated human nasal epithelial cells (WD-NE) after RSV infection alone or after subsequent tumor necrosis factor (TNF)-alpha stimulation. STUDY DESIGN: In vitro investigation. METHODS: Human nasal epithelial cells were obtained from surgical specimens and allowed to differentiate in air-liquid interface cultures until ciliation and mucus production were evident. Two experimental paradigms were used. First, accumulation of cytokines in the media was measured by real-time, quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay after RSV infection alone. In the second set of experiments, cytokines were also measured after TNF-alpha stimulation in both RSV-infected and uninfected cultures. RESULTS: RSV infection of WD-NE resulted in significant accumulations of interleukin (IL)-6, IL-8, and RANTES when compared with findings in control samples. Real-time, quantitative RT-PCR demonstrated significant increases in IL-8 gene expression following RSV infection when compared to controls. Secondary TNF-alpha stimulation following well-established (i.e., 72 h) RSV infection induced marked increases in IL-6, IL-8, and RANTES when compared with both RSV infection alone and TNF-alpha stimulation alone. CONCLUSIONS: These findings suggest that RSV infection primes nasal epithelial cells to secondary proinflammatory challenge, resulting in a hyperimmune response. RSV-induced priming of a hyperimmune response may be important in the pathogenesis of sinusitis, acute otitis media, and pneumonia.