The Potential and Challenges of Nanopore Sequencing

A nanopore-based device provides single-molecule detection and analytical capabilities that are achieved by electrophoretically driving molecules in solution through a nano-scale pore. The nanopore provides a highly confined space within which single nucleic acid polymers can be analyzed at high throughput by one of a variety of means, and the perfect processivity that can be enforced in a narrow pore ensures that the native order of the nucleobases in a polynucleotide is reflected in the sequence of signals that is detected. Kilobase length polymers (single-stranded genomic DNA or RNA) or small molecules (e.g., nucleosides) can be identified and characterized without amplification or labeling, a unique analytical capability that makes inexpensive, rapid DNA sequencing a possibility. Further research and development to overcome current challenges to nanopore identification of each successive nucleotide in a DNA strand offers the prospect of ‘third generation’ instruments that will sequence a diploid mammalian genome for ~$1,000 in ~24 h.Molecular and Cellular BiologyPhysic

Fifteen-Year Trends in Lower Limb Amputation, Revascularization, and Preventive Measures Among Medicare Patients

Although severe lower extremity peripheral arterial disease affects more than 12 million people in the United State secular trends in the risk of amputation remain unexplored in recent years. Using national billing and survey data sets from the Centers for Medicare and Medicaid Services and the Behavioral Risk Factor Surveillance System, we examined trends in lower extremity amputation rates, diagnostic and therapeutic vascular procedures, and the use of preventive measures aimed at limiting the use of amputation procedures in the United States between 1996 and 2011

Endovascular abdominal aortic aneurysm repair: Long-term outcome measures in patients at high-risk for open surgery

Purpose: The study was conducted to determine the outcome in the United States after endovascular repair (EVAR) of infrarenal abdominal aortic aneurysms (AAAs) in patients at high-risk for open surgery by using independently audited, high-compliance, chart-verified data sets, and to compare those results with open surgery. Methods: High-risk was defined to match a recent European trial (EVAR2) and included age of ≥60 years with aneurysm size of ≥5.5 cm, plus at least one cardiac, pulmonary, or renal comorbidity. Data from five multicenter investigational device exemption clinical trials leading to Food and Drug Administration (FDA) approval were analyzed. Of 2216 EVAR patients, 565 met the high-risk criteria. Of 342 surgical controls (OPEN), 61 met high-risk criteria. Primary outcome comparisons included AAA-related death, all-cause death, and aneurysm rupture. Secondary measures were endoleak, AAA sac enlargement, and migration. Results: Average age of the high-risk EVAR subset was 76 ± 7 years vs 74 ± 6 years OPEN (P = 0.07), mean EVAR AAA size was 6.4 ± 0.8 cm vs 6.6 ± 1.0 cm OPEN (P = .33), and average EVAR follow-up was 2.7 years vs 2.5 years OPEN. The 30-day operative mortality was 2.9% in EVAR vs 5.1% in OPEN (P = .32). The AAA-related death rate after EVAR was 3.0% at 1 year and 4.2% at 4 years compared with 5.1% at both time points after OPEN (P = .58). Overall survival at 4 years after EVAR was 56% vs 66% in OPEN (P = .23). After treatment, EVAR successfully prevented rupture in 99.5% at 1 year and in 97.2% at 4 years. Conclusions: Endovascular repair of large infrarenal AAAs in anatomically suited high-surgical-risk patients using FDA-approved devices in the United States is safe and provides lasting protection from AAA-related mortality. EVAR mortality remained comparable with OPEN up to 4 years. The decision to treat AAAs in patients with advanced age and significant comorbidities must be individualized and carefully considered, but repair provides excellent protection from AAA-related death. © 2006 The Society for Vascular Surgery

Lifeline registry of endovascular aneurysm repair: Open repair surgical controls in clinical trials

Purpose: The improvement of available endovascular aortic aneurysm repair (EVAR) devices is critical for the advancement of patient care in vascular surgery. The goal of this article is to report a highly detailed, closely monitored, audited, pooled multicenter cohort of open surgical abdominal aortic aneurysm (AAA) repairs that has potential for use in future EVAR studies as a control data set. Methods: Open surgical AAA repair data from four investigational device exemption clinical aortic endograft trials were tested for poolability, merged, and analyzed for the intervals of 0 to 30 days and 31 to 365 days. Results: The data set includes 323 open patients (83% men; mean age, 70 years). Operative mortality at 30 days was 2.8%. The mean age of women was 3 years older than men, and mortality at 30 days for women was 5.7% compared with 2.2% for men (P = .18). Operative mortality for patients with large AAAs (≥5.5 cm, 3.6%) was not different than for patients with small aneurysms (\u3c5.5 cm, 2.4%, P = .54). All-cause mortality at 1 year was 6.7%, with significant predictors including age, sex, and renal failure. Women had 2.6-fold greater 1-year all-cause mortality rate (13.2%) than men (5.4%, P = .04), but statistical significance was lost after correction for age. Two additional AAA-related deaths occurred between days 31 and 365, resulting in a 1-year AAA-related mortality of 3.5%. Conclusion: This data set provides a tightly controlled, thoroughly detailed, and audited experience that has the potential to serve as an open control group for future EVAR trials. © 2008 The Society for Vascular Surgery

Risk-adjusted 30-day outcomes of carotid stenting and endarterectomy: Results from the SVS Vascular Registry

Objective: As the first operational societal registry of carotid procedures, the Outcomes Committee of the Society for Vascular Surgery (SVS) developed the Vascular Registry (VR) in response to the Centers for Medicare and Medicaid Services\u27 (CMS) National Coverage Decision on carotid artery stenting (CAS). Although CMS requires data submission only on CAS, the VR collects similar data on carotid endarterectomy (CEA) to allow comparison of outcomes, as well as potential for expansion to other procedures. Methods: SVS-VR on-line provider-reported data include baseline through follow-up visits to better understand long-term risks and benefits associated with CAS and CEA. The primary outcomes are combined death, stroke, and myocardial infarction (MI). An independent data coordinating center maintains the database, which is Health Insurance Portability and Accountability Act (HIPAA)-compliant and auditable. Results: As of December 26, 2007, 6403 procedures with discharge data were entered by 287 providers at 56 centers on 2763 CAS patients (1450 with 30-day outcomes, 52.5%) and 3259 CEA patients (1368 with 30-day outcomes, 42%). Of the total cohort, 98% of CEA and 70.7% of CAS (P \u3c .001) were performed for atherosclerotic disease. Restenosis accounted for 22.3% and post-radiation induced stenosis in 4.5% of CAS patients. Preprocedure lateralizing neurologic symptoms were present in a greater proportion of CAS patients (49.2%) than CEA patients (42.4%, P \u3c .001). CAS patients also had higher preprocedure prevalence of coronary artery disease (CAD), MI, congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), and cardiac arrhythmia. For CAS, death/stroke/MI at 30 days was 7.13% for symptomatic patients and 4.60% for asymptomatic patients (P = .04). For CEA, death/stroke/MI at 30 days was 3.75% in symptomatic patients and 1.97% in asymptomatic patients (P = .05). After risk-adjustment for age, history of stroke, diabetes, and American Society of Anesthesiologists (ASA) grade (ie, factors found to be significant confounders in outcomes using backwards elimination), logistic regression analysis suggested better outcomes following CEA. There were no statistically significant differences when examining CAS outcomes based on center volume. CAS in atherosclerotic disease had significantly worse outcomes than in nonatherosclerotic stenosis. When CAS and CEA were compared in the treatment of atherosclerotic disease only, the difference in outcomes between the two procedures was more pronounced, with death/stroke/MI 6.42% after CAS vs 2.62% following CEA, P \u3c .0001. Conclusion: Following best possible risk adjustment of these unmatched groups, symptomatic and asymptomatic CAS patients had significantly higher 30-day postprocedure incidence of death/stroke/MI when compared with CEA patients. The initial 1.5 years of data collection provide proof of concept that a specialty society based VR can succeed in meeting regulatory and scientific goals. With continued enrollment and follow-up, analysis of SVS-VR will supplement randomized trials by providing real-world comparisons of CAS and CEA with sufficient numbers to serve as an outcome assessment tool of important patient subsets and across the spectrum of peripheral vascular procedures. © 2009 The Society for Vascular Surgery