Kimon Bekelis

De-adoption and exnovation in the use of carotid revascularization: retrospective cohort study

Objective To determine physician characteristics associated with exnovation (scaling back on use) and de-adoption (abandoning use) of carotid revascularization. Design Retrospective longitudinal cohort study. Setting Medicare claims linked to the Doximity database provider registry, 2006-13. Participants 9158 physicians who performed carotid revascularization on Medicare patients between 2006 and 2013. Main outcome measures The primary outcomes were the number of carotid revascularization procedures for each physician per year at the end of the sample period, and the percentage change in the volume of carotid revascularization procedures. Results At baseline (2006-07), 9158 physicians performed carotid revascularization. By 2012-13 the use of revascularization in this cohort had declined by 37.7%, with two thirds attributable to scaling back (exnovation) rather than dropping the procedure entirely (de-adoption). Compared with physicians with fewer than 12 years of experience, those with more than 25 years of experience decreased use by an additional 23.0% (95% confidence interval −36.7% to −9.2%). The lowest rates of decline occurred in physicians specializing in vascular or thoracic surgery, for whom the procedures accounted for a large share of revenue. Physicians with high proportions of patients aged more than 80 years or with asymptomatic carotid stenosis were less likely to reduce their use of carotid revascularization. Conclusion Surgeons with more experience and the lowest share in carotid revascularization practice reduced their use of the procedure the most. These practice factors should be considered in quality improvement efforts when the evidence base evolves away from a specific treatment.

Flow diversion with the pipeline embolization device for patients with intracranial aneurysms and antiplatelet therapy: A systematic literature review

Flow diversion with the Pipeline Embolization Device (PED) is reported as a safe and efficient treatment for patients with intracranial aneurysms; however, literature discussing the antiplatelet (APT) regimen used before and after the PED is limited. Our aim was to systematically review and summarize available data regarding the APT regimen and the platelet function test (PFT) that was used. We also sought to provide an overview of the aneurysm morphologies and adverse event rates associated with the PED use. This systematic review was conducted according to the PRISMA statement and eligible studies were identified through search of the PubMed and Cochrane databases. We reviewed 28 studies, involving 1556 patients that underwent aneurysm treatment with the PED. The preprocedural aspirin (ASA) 300- 325mg (2-14days) combined with clopidogrel 75mg (3 to >10days) were used as a treatment strategy in 61.7% of patients and ASA 81mg with clopidogrel 75mg for 5-10days for 27%. Patients who received low versus high dose pre-PED ASA, were at less risk for a hemorrhagic event (0.7% versus 3.3%, p=0.053); however no statistical significance was reached. There was also lack of relationship between patients that received low versus high preprocedural ASA in terms of thromboembolic events. Regarding postprocedural APT, ASA (>6months) and clopidogrel (3- 12 months) was the regimen of choice for 93% of patients. Most studies conducted at least one PFT, most common being the VerifyNow. The most frequently reported target P2Y12 Reaction unit (PRU) and Aspirin Reaction Unit (ARU) values were <230 and <550 respectively. There was no statistically demonstrable difference in regards to thrombotic events between centers that conducted at least one PFT and centers that did not test their patients with a PFT. The overall rates of symptomatic thrombotic episodes were 6.6% and hemorrhagic were 3%. The pre- and post-PED APT dose and duration varies across different institutions. More prospective studies are needed to compare the efficacy of different APT agents and reach conclusions regarding use of PFT and platelet reaction values in order to decrease hemorrhagic and thromboembolic complications associated with the PED.

A comparison of two stroke cohorts cared for by two different specialties in a practice-based tele-stroke population

OBJECTIVESnNeurologists have continually led the assessment and management of Acute Ischemic Stroke(AIS) by use of IV-rtPA, anti-platelet therapy, antihypertensives, and other pharmacologic agents. Since the advent of mechanical thrombectomy(MT) and its proven efficacy, neurovascular surgeons(NS) are playing an increasingly important role in the management and overall care of AIS. We assessed outcomes of AIS patients managed by NS, who have been traditionally managed by neurologists.nnnPATIENTS AND METHODSnOutcomes of AIS patients who presented to the telestroke system, over a 5-year period, were assessed. NIHSS and mRS stroke scales were used as outcome metrics. Multivariate analysis was conducted to compare outcomes of patients treated by neurovascular surgeons and those treated by neurologists.nnnRESULTSn1353 AIS patients were identified. 21.6% received care from neurosurgeons and 78.4% received care from neurologists. Of the neurologist-managed group: 7.8% received MT and were followed by NS, 34% received IVrt-PA, average discharge NIHSSu202f=u202f9.0 (SDu202f=u202f8.42), latest follow-up mRSu202f<u202f2u202f=u202f57.5% and mortality rateu202f=u202f9.4%. Of the neurovascular surgeon-managed group: 7.4% patients received MT, 20% received IVrt-PA, average discharge NIHSSu202f=u202f0.14(SDu202f=u202f0.72), latest follow-up mRSu202f≤2u202f=u202f98.6% and mortality rateu202f=u202f8.3%. There were no significant differences between groups in MT use (OR 1.22; CI95%, 0.971-2.09; pu202f=u202f0.464), IVrt-PA administration (OR 0.98; CI95%, 0.70-1.38; pu202f=u202f0.924), mortality rate (OR 1.21; 0.71-2.03; pu202f=u202f0.483) and patients latest mRS, pu202f=u202f0.873.nnnCONCLUSIONSnAIS requires multidisciplinary management. Care provided by neurosurgeons has similar efficacy and patient outcomes as the care provided by neurologists. These findings support the role and ability of neurosurgeons to manage and care for these patients.

Safety and Efficacy of a 600-mg Loading Dose of Clopidogrel 24 Hours Before Pipeline Embolization Device Treatment

BACKGROUNDnClopidogrel/aspirin antiplatelet therapy routinely is administered 7-10 days before pipeline aneurysm treatment. Our study assessed the safety and efficacy of a 600-mg loading dose of clopidogrel 24 hours before Pipeline Embolization Device (PED) treatment.nnnMETHODSnWe performed a retrospective cohort study involving patients treated with pipeline from October 2010 to May 2016. A total of 39.7% (nxa0= 158) of patients were dispensed a loading dose of 650 mg of aspirin plus at least 600 mg of clopidogrel 24 hours preceding PED deployment; 60.3% (nxa0= 240) received 81-325 mg of aspirin daily for 10 days with 75 mg of clopidogrel daily preprocedurally. The mean follow-up was 15.8 months (standard deviation [SD] 12.4 months). modified Rankin Scale (mRS) was registered before the discharge and at each follow-up visit. To control confounding, we used multivariable logistic regression and propensity score conditioning.nnnRESULTSnOf 398 patients, the proportion of female patients was ≈16.5% (41/240) in both groups and shared the same mean of age ≈56.46 years. Similarly, ≈12.2% (meanxa0= 0.09; SDxa0= 0.30) had a subarachnoid hemorrhage. A total of 92% (meanxa0= 0.29; SDxa0= 0.70) from the pretreatment group and 85.7% (meanxa0= 0.44; SDxa0= 0.91) of the bolus group had a mRS ≤2. In a multivariate analysis, bolus did not affect the mRS score, Pxa0= 0.24. Seven patients had a long-term recurrence, 2 (0.83%; meanxa0= 0.01; SDxa0= 0.10) from the pretreatment group. In a multivariable logistic regression, bolus was not associated with a long-term recurrence rate (odds ratio [OR] 1.91; 95% confidence interval [CI] 0.27-13.50; Pxa0= 0.52) neither with thromboembolic accidents (OR 0.99; 95% CI 0.96-1.03; Pxa0= 0.83) nor with hemorrhagic events (OR 1.00; 95% CI 0.97-1.03; Pxa0= 0.99). Three patients died: 1 who received a bolus had an acute subarachnoid hemorrhage. The mean mortality rate was parallel in both groups ≈0.25 (SDxa0= 0.16). Bolus was not associated with mortality (ORxa01.11; 95% CI 0.26-4.65; Pxa0= 0.89). The same associations were present in propensity score-adjusted models.nnnCONCLUSIONSnIn a cohort receiving PED, a 600-mg loading dose of clopidogrel should be safe and efficacious in those off the standard protocol or showing <30% platelet inhibition before treatment.

Response by Bekelis et al to Letter Regarding Article, “Anesthesia Technique and Outcomes of Mechanical Thrombectomy in Patients With Acute Ischemic Stroke”

We want to thank Drs Dexter and Hindman for their interest in our article.1 Our analysis has attempted to address the authors’ first concern. Clustering of observations in 1 particular hospital was addressed by using mixed effects methods with hospital identity as a random effects variable. Unmeasured confounding was addressed using an instrumental variable analysis. The regional rate of general anesthesia (hospital-level general anesthesia rate) was used as …

The use of alternatives to clopidogrel in flow-diversion treatment with the Pipeline embolization device

OBJECTIVEThromboembolic complications continue to be encountered with Pipeline embolization devices (PEDs) despite routine clopidogrel/aspirin antiplatelet therapy. This study examined the safety and efficacy of prasugrel in the management of clopidogrel-resistant patients treated for cerebral aneurysms.METHODSFour hundred thirty-seven consecutive patients were identified between January 2011 and May 2016. Patients allergic, or having less than 30% platelet inhibition, to a daily 75-mg dose of clopidogrel received 10 mg of prasugrel daily (n = 20) or 90 mg of ticagrelor twice daily (n = 2). The mean (± SD) follow-up duration was 15.8 ± 12.4 months. The primary outcome was the modified Rankin Scale (mRS) score registered before discharge and at each follow-up visit. To control confounding, multivariable mixed-effects logistic regression and propensity score conditioning were used.RESULTSTwenty-six (5.9%) of 437 patients presented with a subarachnoid hemorrhage (SAH). The mean patient age was 56.3 years, and 62 were women (14.2%). One of the 7 patients lost to follow-up received prasugrel. One patient was allergic to clopidogrel and prasugrel simultaneously. All patients receiving prasugrel or ticagrelor (n = 22) had an mRS score ≤ 2 on their latest follow-up visit (mean score 0.67 ± 1.15). In a multivariate analysis, clopidogrel did not affect the mRS score on last follow-up (p = 0.14). Multivariable logistic regression showed that clopidogrel was not associated with an increased long-term recurrence rate (OR 0.17, 95% CI 0.01-2.70, p = 0.21), an increased thromboembolic complication rate (OR 0.46, 95% CI 0.12-1.67, p = 0.24), or an increased hemorrhagic event rate (OR 0.39, 95% CI 0.91-1.64, p = 0.20). None of the patients receiving prasugrel or ticagrelor died or suffered a long-term recurrence or a hemorrhagic event; only 1 patient suffered from mild aphasia subsequent to a thromboembolic event. Three patients taking clopidogrel died during the study: 2 from acute SAH and 1 from intraparenchymal hemorrhage. Clopidogrel was not associated with an increased mortality rate (OR 2.18, 95% CI 0.11-43.27, p = 0.61). The same associations were present in propensity score-adjusted models.CONCLUSIONSIn a cohort of patients treated with PEDs, prasugrel (10 mg/day) was a safe alternative to clopidogrel-resistant or clopidogrel-allergic patients, or nonresponders.

Does Rapid Diffusion of HbA1c Testing Affect Amputation Rates

Background: The association of speed of diffusion of Hemoglobin A1C (hbA1c) testing with temporal changes in outcomes of primary importance to patients with diabetes, such as amputation, remains an issue of debate. We investigated these correlations. Methods: We performed a retrospective cohort study of diabetics, based on Medicare fee-for-service claims data from 2002 to 2012. We examined the association of the rate of diffusion of HbA1c testing with changes in amputation rates. Our unit of analysis was the hospital referral region (HRR), a definition of tertiary care markets defined in the Dartmouth Atlas of Health Care. Results: From the 11 096 270 diabetics followed in our study for a mean follow-up of 4.1 years, 106 340 (0.96%) underwent lower extremity amputations. The speed of diffusion of HbA1c testing had a moderate association with the speed of diffusion of lower extremity amputations, after adjusting for multiple factors including baseline regional amputation and testing rates (adjusted difference, −0.7%; 95% confidence interval, −1.0% to −0.3%). The risk-adjusted HRR-level speed of diffusion of testing demonstrated significant correlation with the risk-adjusted HRR-level diffusion of amputations (r = .250, P < .001). Conclusions: We observed a moderate association of the speed of diffusion of HbA1c testing with the speed of diffusion of lower extremity amputations among Medicare patients with diabetes. Improvements in performance on quality metrics such as HbA1c testing may not immediately translate into tangible patient outcomes.