Feasibility of concomitant vacuum-assisted removal of lead-related vegetations and cardiac implantable electronic device extraction.

BACKGROUND: Cardiac implantable electronic device (CIED) infections associated with large, mobile vegetation adds to the complexity of lead extraction and is associated with significant patient morbidity and mortality. OBJECTIVE: To show the feasibility of concomitant cardiovascular implantable electronic device extraction and vacuum-assisted removal of lead-related vegetations. METHODS: This is a single-center retrospective case series of consecutive patients with persistent bacteremia, sepsis, or endocarditis despite medical therapy who have vegetations >2 cm and subsequently underwent immediate CIED lead extraction after debulking with vacuum-assisted suction. RESULTS: Eight patients underwent successful removal of 17 leads immediately after debulking of vegetations with vacuum-assisted device suction. Debulking procedure was not successful in 1 patient due to inability to direct the vacuum suction device into proper position. There were no intraprocedure complications related to the vacuum-assisted debulking. One patient required open sternotomy for tear of the coronary sinus ostium related to extraction of a left ventricular pacing electrode. There was no mortality within 30 days of the procedure. CONCLUSIONS: Based upon these clinical results, it is feasible for patients with infected CIED systems that have large right-sided vegetations to undergo vacuum-assisted debulking then immediately followed by percutaneous CIED removal in whom surgical removal is considered high risk.

Perioperative management of oral anticoagulation in patients undergoing implantation of subcutaneous implantable cardioverter-defibrillator.

BACKGROUND: The perioperative anticoagulation management during subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation is still evolving. OBJECTIVE: The purpose of this study was to assess whether it is safe to perform S-ICD implantation with uninterrupted warfarin. METHODS: This is a single-center retrospective review of patients undergoing S-ICD implantation between October 1, 2012 and June 30, 2017. One hundred thirty-seven patients underwent successful S-ICD implantation during the study period. The most common indication for implantation was primary prevention of sudden cardiac death. In 24 (17.5%) patients, warfarin was continued without any interruption (warfarin group). In 113 (82.5%) patients, no warfarin was used in the perioperative period (nonwarfarin group). The incidence of clinically significant lateral pocket hematoma was compared in the 2 groups. RESULTS: The mean international normalized ratio was 1.83 ± 0.47 in the warfarin group and 1.09 ± 0.18 in the nonwarfarin group. A total of 8 patients developed a hematoma at the lateral pocket. No patient developed a hematoma at the parasternal pockets. Six patients (25%) in the warfarin group and 2 (1.5%) in the nonwarfarin group developed a significant lateral pocket hematoma (P = .001). The mean length of stay was longer in the warfarin group (1.23 ± 0.46 days) than in the nonwarfarin group (1.02 ± 0.18 days) (P = .0008). An international normalized ratio of >1.8 predicted the risk of hematoma. The concomitant use of dual antiplatelet therapy did not increase the risk of hematoma. None of the patients with a hematoma developed infection or required hematoma evacuation. CONCLUSION: Uninterrupted warfarin in the perioperative period during S-ICD implantation is associated with an increased risk of significant lateral pocket hematoma that results in prolonged hospital stay.

Initiation and outcomes with Class Ic antiarrhythmic drug therapy.

BACKGROUND: Expert opinion recommends performing exercise testing with initiation of Class Ic antiarrhythmic medication. OBJECTIVE: To evaluate the rate and reason for discontinuation of Ic agent within the first year of follow up, with particular attention to rate of proarrhythmia and the value of routine treadmill testing. METHODS: This is a single center retrospective cohort study including consecutive patients with atrial arrhythmias who were initiated on a Class Ic agent from 2011 to 2016. Data was collated from chart review and pharmacy database. RESULTS: The study population included 300 patients (55% male, mean age 61; mean ejection fraction, 56%) started on flecainide (n = 153; 51%) and propafenone (n = 147; 49%). Drug initiation was completed while hospitalized on telemetry and the staff electrophysiologists directed dosing. There was one proarrhythmic event during initiation (0.3%). The primary reason for not being discharged on Ic agent was due to detection of proarrhythmia (n = 15) or ischemia (n = 1) with treadmill testing (5.3%). Exercise testing was the single significant variable to affect the decision to discontinue Ic drug, p < 0.0001 (95% CI: 1.89-6.08%). During follow up, the primary reason for discontinuation of Ic agent was lack of efficacy, 32%. CONCLUSIONS: With proper screening, initiation of Class Ic agent is associated with very low rate of proarrhythmia. Treadmill testing is of incremental value and should be completed in all patients after loading Class Ic antiarrhythmic.

Role of exercise electrocardiogram to screen for T-wave oversensing after implantation of subcutaneous implantable cardioverter-defibrillator.

BACKGROUND: During early experience with subcutaneous implantable cardioverter-defibrillators (S-ICD), several patients had inappropriate shocks from T-wave oversensing (TWOS) during exercise. This prompted some operators to perform routine treadmill exercise tests after implantation of S-ICD to screen for TWOS. Meanwhile, improvements have been made in the detection algorithms by the manufacturer. OBJECTIVE: To assess whether routine treadmill exercise post S-ICD implantation is warranted. METHODS: Patients undergoing S-ICD implantation from October 2012 to December 2016 who were able to complete a treadmill exercise were included in the study. The amplitude of R and T waves as assessed by the device programmer at rest and peak exercise was calculated and incidence of TWOS recorded. RESULTS: Eighty-seven patients with complete treadmill exercise test data were included in the final analysis. The majority of the patients received S-ICD for primary prevention. Nine percent of the included patients had hypertrophic obstructive cardiomyopathy. During treadmill exercise, there was significant increase in the heart rate from rest (77 ± 14 beats per minute) to peak exercise (133 ± 14 beats per minute; P < .0001). There was no significant difference between R-wave amplitude at rest (2 ± 0.77 mV) and peak exercise (1.88 ± 0.94 mV; P = .36). Similarly, there was no significant difference between T-wave amplitude at rest (0.27 ± 0.19 mV) and peak exercise (0.33 ± 0.23 mV; P = .06). The incidence of TWOS during exercise was zero. CONCLUSIONS: With current screening and detection algorithms for S-ICD, routine treadmill exercise does not result in additional discrimination of patients susceptible to TWOS.

Comparison of Approaches for Stroke Prophylaxis in Patients with Non-Valvular Atrial Fibrillation: Network Meta-Analyses of Randomized Controlled Trials.

BACKGROUND: Multiple novel oral anticoagulants and left atrial appendage closure devices (WATCHMAN) have been tested against dose-adjusted vitamin K antagonists in randomized controlled trials for stroke prophylaxis in non-valvular atrial fibrillation. No direct comparisons of these strategies are available from randomized controlled trials. We conducted the current analyses by combining efficacy and safety characteristics of all FDA approved stroke prophylaxis treatment strategies for patients with non-valvular atrial fibrillation. MATERIALS AND METHODS: We searched SCOPUS from 1945 till October 2015 for randomized controlled trials comparing these strategies and reporting efficacy and safety outcomes. Six randomized controlled trials were identified and included in the final analyses and review. We followed PRISMA guidelines for network meta-analyses while reporting the current analyses. We collected data on ischemic stroke, major bleeding, and the composite primary safety endpoint as defined by various randomized controlled trials. Network meta-analyses were conducted using consistency and inconsistency models for efficacy and safety outcomes. Surface under the cumulative ranking curve were then utilized to cluster rank these treatments for safety and efficacy. RESULTS: Six randomized controlled trials with 59,627 patients comparing six treatment strategies were eligible for the analyses. All prophylaxis strategies had comparable rates of ischemic stroke. Apixaban was associated with the least number of primary safety endpoint events as compared with all other treatments. In the cluster analyses assessing safety and efficacy, apixaban, edoxaban and dabigatran ranked best followed by vitamin K antagonists and rivaroxaban, whereas the WATCHMAN left atrial appendage closure device ranked last. CONCLUSIONS: Dose-adjusted vitamin K antagonists, novel oral anticoagulants, and the WATCHMAN left atrial appendage closure devices are equally efficacious for ischemic stroke prevention but these treatments have different safety profiles. More randomized controlled trials are needed to directly compare these strategies.

Intermediary variables and algorithm parameters for an electronic algorithm for intravenous insulin infusion.

BACKGROUND: Algorithms for intravenous insulin infusion may assign the infusion rate (IR) by a two-step process. First, the previous insulin infusion rate (IR(previous)) and the rate of change of blood glucose (BG) from the previous iteration of the algorithm are used to estimate the maintenance rate (MR) of insulin infusion. Second, the insulin IR for the next iteration (IR(next)) is assigned to be commensurate with the MR and the distance of the current blood glucose (BG(current)) from target. With use of a specific set of algorithm parameter values, a family of iso-MR curves is created, each giving IR as a function of MR and BG. METHOD: To test the feasibility of estimating MR from the IR(previous) and the previous rate of change of BG, historical hyperglycemic data points were used to compute the "maintenance rate cross step next estimate" (MR(csne)). Historical cases had been treated with intravenous insulin infusion using a tabular protocol that estimated MR according to column-change rules. The mean IR on historical stable intervals (MR(true)), an estimate of the biologic value of MR, was compared to MR(csne) during the hyperglycemic iteration immediately preceding the stable interval. Hypothetically calculated MR(csne)-dependent IR(next) was compared to IR(next) assigned historically. An expanded theory of an algorithm is developed mathematically. Practical recommendations for computerization are proposed. RESULTS: The MR(true) determined on each of 30 stable intervals and the MR(csne) during the immediately preceding hyperglycemic iteration differed, having medians with interquartile ranges 2.7 (1.2-3.7) and 3.2 (1.5-4.6) units/h, respectively. However, these estimates of MR were strongly correlated (R(2) = 0.88). During hyperglycemia at 941 time points the IR(next) assigned historically and the hypothetically calculated MR(csne)-dependent IR(next) differed, having medians with interquartile ranges 4.0 (3.0-6.0) and 4.6 (3.0-6.8) units/h, respectively, but these paired values again were correlated (R(2) = 0.87). This article describes a programmable algorithm for intravenous insulin infusion. The fundamental equation of the algorithm gives the relationship among IR; the biologic parameter MR; and two variables expressing an instantaneous rate of change of BG, one of which must be zero at any given point in time and the other positive, negative, or zero, namely the rate of change of BG from below target (rate of ascent) and the rate of change of BG from above target (rate of descent). In addition to user-definable parameters, three special algorithm parameters discoverable in nature are described: the maximum rate of the spontaneous ascent of blood glucose during nonhypoglycemia, the glucose per daily dose of insulin exogenously mediated, and the MR at given patient time points. User-assignable parameters will facilitate adaptation to different patient populations. CONCLUSIONS: An algorithm is described that estimates MR prior to the attainment of euglycemia and computes MR-dependent values for IR(next). Design features address glycemic variability, promote safety with respect to hypoglycemia, and define a method for specifying glycemic targets that are allowed to differ according to patient condition.

No patient left behind: evaluation and design of intravenous insulin infusion algorithms.

OBJECTIVE: To define the characteristics of performance evaluation, algorithm design, and regulation of insulin delivery by which professionals and the healthcare system might differentiate between methodologies for intravenous insulin infusion. METHODS: Published performance criteria used in the assessment of intravenous insulin infusion algorithms are classified. The structure of intravenous insulin infusion formulae is reviewed, as are technologies that might lead to future improvement. RESULTS: Among published reports, no standardization was discernable for description of algorithm characteristics or performance. Except for time-to-target and hypoglycemic episodes, measures using the patient as unit of observation are not employed consistently. CONCLUSION: The healthcare system needs criteria for evaluation and minimal acceptable standards for assessing performance of any algorithm, decision support system, or closed-loop system for intravenous insulin infusion. Inclusion of patient-based measures is necessary to assess the ability of an algorithm to control variability between patients and within a given run. Standardization of performance reporting will help users to select appropriate methodologies.