Prasad Jetty

Incidence, follow-up, and outcomes of incidental abdominal aortic aneurysms

BACKGROUND Incidental abdominal aortic aneurysms (AAAs) are identified during imaging for other reasons. Incidental AAAs are important findings because they require monitoring and surgical treatment, when indicated, to prevent rupture. The prevalence of incidental AAAs and their management has not been extensively studied. METHODS We electronically screened a 25% simple random sample of abdominal computed tomography (CT), ultrasound (US), and magnetic resonance imaging (MRI) studies conducted between 1996 and 2008 at one academic medical center. Screen-positive reports were manually reviewed to determine if they showed an incidental AAA. We reviewed the medical records of all in-patients to determine whether the incidental AAA was documented, a treatment plan was identified, and whether it was communicated to the patients family physician through the discharge summary. We used evidence-based recommended schedules to determine the adequacy of AAA monitoring for each person. RESULTS In 79,121 abdominal images, we identified 812 incidental AAAs (1.0% of all studies) or 364 incidental AAAs annually (95% confidence interval [CI], 349-379). Patients were elderly (mean age, 74 years), and AAAs were a mean diameter of 4.0 cm. For 174 inpatients, AAAs were noted in only 51 patients (29%) and only 25 (15%) were communicated to the family physician. Of 329 patients who were observed beyond their first recommended follow-up scan, only 51 (16%) were monitored appropriately throughout their entire follow-up; the median proportion of follow-up time with recommended monitoring was 56% (interquartile range, 32%-82%). Elective AAA repair was done in 98 patients (13%), the probability of which was significantly increased when AAA monitoring frequency was compliant with that recommended in practice guidelines. Six patients (0.8%) were admitted with aortic rupture, the probability of which was independent of AAA monitoring. CONCLUSION Incidental AAAs are common and appear to be poorly monitored. Our data suggested that improved monitoring of incidental AAAs was independently associated with elective AAA repair. Population-based analyses are required to determine the influence that monitoring has on incidental AAA rupture and patient mortality.

Superficial femoral artery nitinol stent in a patient with nickel allergy

We present a case of a patient who developed a systemic allergic reaction following placement of a nitnol stent in the superficial femoral artery for claudication symptoms. Shortly after, he was tested for contact dermatitis and found to have a severe reaction to nickel. His symptoms of severe itch and generalized rash resolved within days following stent explantation and reconstruction with a vein graft. The epidemiology and clinical significance of nickel allergy and the concomitant use of nickel-alloy stents are discussed.

Wait times among patients with symptomatic carotid artery stenosis requiring carotid endarterectomy for stroke prevention

BACKGROUND Current Canadian and international guidelines suggest patients with transient ischemic attack (TIA) or nondisabling stroke and ipsilateral internal carotid artery stenosis of 50% to 99% should be offered carotid endarterectomy (CEA) ≤ 2 weeks of the incident TIA or stroke. The objective of the study was to identify whether these goals are being met and the factors that most influence wait times. METHODS Patients who underwent CEA at the Ottawa Hospital for symptomatic carotid artery stenosis from 2008 to 2010 were identified. Time intervals based on the dates of initial symptoms, referral to and visit with a vascular surgeon, the decision to operate, and the date of surgery were recorded for each patient. The influence of various factors on wait times was explored, including age, sex, type of index event, referring physician, distance from the surgical center, degree of stenosis, and surgeon assigned. RESULTS Of the 117 patients who underwent CEA, 92 (78.6%) were symptomatic. The median time from onset of symptoms to surgery for all patients was 79 days (interquartile range [IQR], 34-161). The shortest wait times were observed in stroke patients (49 [IQR, 27-81] days) and inpatient referrals (66 [IQR, 25-103] days). Only 7 of the 92 symptomatic patients (8%) received care within the recommended 2 weeks. The median surgical wait time for all patients was 14 days (IQR, 8-25 days). In the multivariable analysis, significant predictors of longer wait times included retinal TIA (P = .003), outpatient referrals (P = .004), and distance from the center (P = .008). Patients who presented to the emergency department had the shortest delays in seeing a vascular surgeon and subsequently undergoing CEA (P < .0001). There was no difference between surgeons for wait times to be seen in the clinic; however, there were significant differences among surgeons once the decision was made to proceed with CEA. CONCLUSIONS Our wait times for CEA currently do not fall within the recommended 2-week guideline nor does it appear feasible within the current system. Important factors contributing to delays include outpatient referrals, living farther from the hospital, and presenting with a retinal TIA (amaurosis fugax). Our findings also suggest better scheduling practices once a decision is made to operate can modestly improve overall and surgical wait times for CEA.

Coding accuracy of abdominal aortic aneurysm repair procedures in administrative databases - a note of caution.

BACKGROUND Administrative databases have been used to compare methods used for abdominal aortic aneurysm (AAA) repair. This requires the use of procedural codes whose accuracy has not been established. In this study we measured the accuracy of procedural codes for open AAA repair and endovascular aneurysm repair (EVAR) in administrative databases. METHODS Between April 2000 and July 2005, we identified all surgeries of non-ruptured AAA using open or EVAR technique at a tertiary-care teaching hospital. During the same time period, we identified all patients who were coded with either an open AAA repair or EVAR. RESULTS During the study period, 514 people had an elective AAA repair or were coded with one. Coding quality of open AAA repair was poor (sensitivity 48.1%; specificity 77.4%; accuracy 52.9%) while that for EVAR was slightly better (sensitivity 58.2%; specificity 100%; accuracy 93.6%). We developed an algorithm that included similar procedures and considered anaesthetic type to improve the identification of both open repair (sensitivity 97.7%; specificity 86.9%; accuracy 95.9%) and EVAR (sensitivity 84.8%; specificity 99.5%; accuracy 97.3%). CONCLUSION Administrative database codes that are routinely used to identify open AAA repairs or EVARs are inaccurate. However, slight modifications to the coding algorithms permit the use of administrative databases to study AAA repair.

Prothrombin G20210A Mutation and Lower Extremity Peripheral Arterial Disease: A Systematic Review and Meta-analysis

OBJECTIVE/BACKGROUND Despite being an important risk factor for venous thromboembolism, the role of the prothrombin G20210A mutation in patients with arterial disease remains unclear. The aim of this review was to evaluate the association of prothrombin G20210A and lower extremity peripheral arterial disease (PAD). METHODS This was a systematic review and meta-analysis of case-control studies. A systematic review of electronic databases, including MEDLINE and Embase, was conducted to assess the prevalence of prothrombin G20210A in patients with lower extremity PAD. The main outcome was the prevalence of prothrombin G20210A in patients with lower extremity PAD. The random effects model odds ratio (OR) was used as the primary outcome measure. RESULTS The initial electronic search identified 168 relevant abstracts of which five studies evaluating 1,524 cases of PAD and 1,553 controls were included. Prothrombin G20210A was found in 70 of 1,524 patients with lower extremity PAD and 44 of 1,553 of the controls (random effects OR 1.68, 95% confidence interval [CI] 0.8-3.2). In those with critical limb ischemia (CLI), the prevalence of prothrombin G20210A was 23 of 302 compared with 31 of 1,253 of the controls (OR 3.2, 95% CI 1.6-6.1). CONCLUSION Despite finding no significant association between lower extremity PAD and prothrombin G20210A, the meta-analysis suggests that the prevalence of prothrombin G20210A is significantly elevated in those with atherosclerotic occlusive disease of the lower extremities presenting with CLI. Well-designed prospective cohort studies evaluating the role of prothrombin G20210A as a predictor of disease progression or adverse vascular events are highly needed.

Delays in carotid endarterectomy: the process is the problem.

BACKGROUND Current recommendations for carotid endarterectomy (CEA) for symptomatic carotid stenosis state benefit is greatest when performed within two weeks of symptoms. However, only a minority of cases are operated on within this guideline, and no systematic examinations of reasons for these delays exist. METHODS All CEA cases performed at our institution by vascular surgery for symptomatic carotid stenosis after neurologist referral in 2008-2009 were reviewed. Dates of symptom onset, initial presentation, referral to and evaluation by neurology and vascular surgery, vascular imaging, and CEA were collected, and the length of time between each analysed. Reasons for delays were noted where available. RESULTS Of 36 included patients, 34 had CEA more than two weeks after symptom onset. Median time to CEA from onset was 76 days (IQR, 38-105 days). Longest intervals were between surgeon assessment and CEA (14 days; IQR, 9-21 days), neurology referral and neurologist assessment (9 days; IQR, 2-26 days), vascular imaging and referral to vascular surgery (9 days; IQR, 2-35 days) and vascular surgery referral and assessment (8 days; IQR, 6-15 days). Few patients (44.1%) had reasons for delays identified; of these, process-related delays were related to delayed vascular imaging, delayed referral by primary care physicians, or multiple conflicting referrals. CONCLUSIONS There are significant delays between symptom onset and CEA in patients referred for CEA, with delay highest between specialist referral and evaluation. Strategies to reduce these delays may be effective in increasing the proportion of procedures performed within two weeks of symptom onset.

Trends in the utilization of endovascular therapy for elective and ruptured abdominal aortic aneurysm procedures in Canada.

OBJECTIVE While randomized trials have shown improved operative mortality with endovascular aneurysm repair (EVAR) but similar long-term mortality rates, enthusiasm for EVAR persists, and rates of EVAR use continue to increase. Currently, knowledge of utilization rates of EVAR in Canada is limited. METHODS Patients who underwent nonruptured abdominal aortic aneurysm (AAA) and ruptured AAA (RAAA) repair, by either open surgical repair (OSR) or EVAR, in Canada were identified from hospital discharge abstract data. Trends in rates for OSR and EVAR were calculated by province and by year, and standardized per 100,000 persons over 65 years of age (per capita). RESULTS Between April 2004 and March 2009, 15,960 AAA procedures were performed in Canada, either by OSR (n=12,204) or EVAR (n=3756). The proportion of all elective AAA procedures by EVAR increased from 11.5% in 2005 to 35.5% in 2009, the highest current proportion of EVAR utilization in British Columbia (45.0%) and the lowest in Manitoba (15.8%). After standardization, the national rate of total procedures was steady, but the rate of RAAAs declined over the entire study period. Alberta consistently had the highest per capita rates of EVAR use (38.9), whereas Prince Edward Island had the lowest (8.4). Provincial variations in EVAR use did not correlate with differences in comorbidities. Compared with Canadian averages, Atlantic Provinces performed the most AAA procedures per capita (137.5 vs 93.4), had the highest rate of RAAAs per capita (29.7 vs 22.2), and had the lowest proportional rates of EVAR use. CONCLUSIONS Use of EVAR in Canada for AAAs has increased in the past 5 years, without affecting overall AAA procedure volumes. Large discrepancies in EVAR use exist across Canada. The Atlantic Provinces had the highest rates of RAAAs despite having the highest rates for total AAA procedures, suggesting a population with higher susceptibility for AAAs. This region may also have the largest potential for future increased use of EVAR.

The influence of incidental abdominal aortic aneurysm monitoring on patient outcomes.

BACKGROUND Incidental abdominal aortic aneurysms (AAAs) are identified when the abdomen is imaged for other reasons. These are common, and many undergo incomplete radiological monitoring. The association between monitoring completeness and population-based outcomes has not been studied. METHODS A cohort of incidental AAAs (defined as previously unidentified aortic enlargement exceeding 3 cm found on an imaging study done for another reason) was linked to population-based data. Patients were followed to elective AAA repair, AAA rupture, death, or March 31, 2009. Monitoring completeness was gauged as the sequential number of months without a recommended abdominal scan. Its association with time to elective AAA repair and time to death was measured using a multivariable Cox regression model adjusting for other important covariates. RESULTS We identified 191 incidental AAAs between 1996 and 2004 (median diameter of 3.5 cm [range, 3.0-5.3 cm], median follow up of 4.4 years [range, 0.6-12.7 years]). During the study, patients spent a median of 19.4% of their time with incomplete AAA monitoring (interquartile range [IQR] 0.3%-44%); 56 patients (29.3%) had no follow-up imaging of their aneurysm. Nineteen patients (10.0%; 2.0% per year) underwent elective AAA repair, and 79 patients (37.7%; 7.6% per year) died. Independent of important covariates, people were significantly less likely to undergo elective repair (hazard ratio [HR], 0.03) and significantly more likely to die (HR, 2.99) if their AAA went without radiological monitoring for 1 year. CONCLUSIONS Incomplete incidental AAA radiological monitoring was significantly associated with a decreased risk of elective AAA repair and an increased risk of death. While uncontrolled confounding might explain part of these associations, clinicians should ensure that radiological monitoring of AAAs is complete in appropriate patients.

Internal iliac coverage during endovascular repair of abdominal aortic aneurysms is a safe option: A preliminary study

Endovascular aneurysm repairs lacking suitable common iliac artery landing zones occasionally require graft limb extension into the external iliac artery, covering the internal iliac artery origin. The purpose of this study was to assess incidence of type II endoleak following simple coverage of internal iliac artery without embolization during endovascular aneurysm repair. Three hundred eighty-nine endovascular aneurysm repairs performed by a single surgeon (2004–2015) were reviewed. Twenty-seven patients underwent simple internal iliac artery coverage. Type II endoleak was assessed from operative reports and follow-up computed tomography imaging. No patient suffered type II endoleak from a covered internal iliac artery in post-operative computed tomography scans. Follow-up ranged from 0.5 to 9 years. No severe pelvic ischemic complications were observed. In conclusion, for selected cases internal iliac artery coverage without embolization is a safe alternative to embolization in endovascular aneurysm repairs, where the graft must be extended into the external iliac artery.

Google Maps offers a new way to evaluate claudication

Background: Accurate determination of walking capacity is important for the clinical diagnosis and management plan for patients with peripheral arterial disease. The current “gold standard” of measurement is walking distance on a treadmill. However, treadmill testing is not always reflective of the patients natural walking conditions, and it may not be fully accessible in every vascular clinic. The objective of this study was to determine whether Google Maps, the readily available GPS‐based mapping tool, offers an accurate and accessible method of evaluating walking distances in vascular claudication patients. Methods: Patients presenting to the outpatient vascular surgery clinic between November 2013 and April 2014 at the Ottawa Hospital with vasculogenic calf, buttock, and thigh claudication symptoms were identified and prospectively enrolled in our study. Onset of claudication symptoms and maximal walking distance (MWD) were evaluated using four tools: history; Walking Impairment Questionnaire (WIQ), a validated claudication survey; Google Maps distance calculator (patients were asked to report their daily walking routes on the Google Maps‐based tool runningmap.com, and walking distances were calculated accordingly); and treadmill testing for onset of symptoms and MWD, recorded in a double‐blinded fashion. Results: Fifteen patients were recruited for the study. Determination of walking distances using Google Maps proved to be more accurate than by both clinical history and WIQ, correlating highly with the gold standard of treadmill testing for both claudication onset (r = .805; P < .001) and MWD (r = .928; P < .0001). In addition, distances were generally under‐reported on history and WIQ. The Google Maps tool was also efficient, with reporting times averaging below 4 minutes. Conclusions: For vascular claudicants with no other walking limitations, Google Maps is a promising new tool that combines the objective strengths of the treadmill test and incorporates real‐world walking environments. It offers an accurate, efficient, inexpensive, and readily accessible way to assess walking distances in patients with peripheral vascular disease.