Dataset Information

Relationship between time-to-isolation and freeze duration: Computational modeling of dosing for Arctic Front Advance and Arctic Front Advance Pro cryoballoons.

ABSTRACT: BACKGROUND:Preclinical and clinical studies have utilized periprocedural parameters to optimize cryoballoon ablation dosing, including acute time-to-isolation (TTI) of the pulmonary vein, balloon rate of freezing, balloon nadir temperature, and balloon-thawing time. This study sought to predict the Arctic Front Advance (AFA) vs Arctic Front Advance Pro (AFA Pro) ablation durations required for transmural pulmonary vein isolation at varied tissue depths. METHODS:A cardiac-specific, three-dimensional computational model that incorporates structural characteristics, temperature-dependent cellular responses, and thermal-conductive properties was designed to predict the propagation of cold isotherms through tissue. The model assumed complete cryoballoon-to-pulmonary vein (PV) circumferential contact. Using known temperature thresholds of cardiac cellular electrical dormancy (at 23°C) and cellular nonviability (at -20°C), transmural time-to-isolation electrical dormancy (TTIED ) and cellular nonviability (TTINV ) were simulated. RESULTS:For cardiac thickness of 0.5, 1.25, 2.0, 3.0, 4.0, and 5.0?mm, the 23°C isotherm passed transmurally in 33, 38, 46, 62, 80, and 95?seconds during cryoablation utilizing AFA and 33, 38, 46, 63, 80, and 95?seconds with AFA Pro. Using the same cardiac thicknesses, the -20°C isotherm passed transmurally in 40, 55, 78, 161, 354, and 696?seconds during cryoablation with AFA and 40, 54, 78, 160, 352, and 722?seconds with AFA Pro. CONCLUSION:This model predicted a minimum duration of cryoballoon ablation (TTINV ) to obtain a transmural lesion when acute TTI of the PV was observed (TTIED ). Consequently, the model is a useful tool for characterizing CBA dosing, which may guide future cryoablation dosing strategies.

SUBMITTER: Getman MK

PROVIDER: S-EPMC6899473 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Relationship between time-to-isolation and freeze duration: Computational modeling of dosing for Arctic Front Advance and Arctic Front Advance Pro cryoballoons.

Getman Michael K MK Wissner Erik E Ranjan Ravi R Lalonde Jean-Pierre JP

Journal of cardiovascular electrophysiology 20190917 11

<h4>Background</h4>Preclinical and clinical studies have utilized periprocedural parameters to optimize cryoballoon ablation dosing, including acute time-to-isolation (TTI) of the pulmonary vein, balloon rate of freezing, balloon nadir temperature, and balloon-thawing time. This study sought to predict the Arctic Front Advance (AFA) vs Arctic Front Advance Pro (AFA Pro) ablation durations required for transmural pulmonary vein isolation at varied tissue depths.<h4>Methods</h4>A cardiac-specific, ...[more]

PMID: 31502304

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Project description:Oritavancin is a novel lipoglycopeptide with demonstrated effectiveness against complicated skin and skin structure infections (cSSSI) caused by Gram-positive pathogens, including those caused by methicillin-resistant Staphylococcus aureus (MRSA). The pharmacokinetic and pharmacodynamic profile of oritavancin is favorable for single or infrequent dosing. A phase 2, multicenter, randomized, double-blind, parallel, active-comparator study (ClinicalTrials.gov identifier, NCT00514527) of single and infrequent dosing of intravenous (i.v.) oritavancin for the treatment of cSSSI caused by Gram-positive pathogens (wound infections, major abscess, and cellulitis) was undertaken to evaluate the noninferiority of front-loaded dosing regimens compared to a daily-dosing regimen. A total of 302 patients ≥ 18 years of age were randomized equally to one of three oritavancin treatment groups, receiving either a daily dose (200 mg) administered for 3 to 7 days, a single dose (1,200 mg), or an infrequent dose (800-mg dose, with the option for an additional 400 mg on day 5). The primary efficacy was defined as a clinical response in clinically evaluable (CE) patients assessed at days 21 to 29 (test of cure [TOC]). The cure rates in the CE population were 72.4% (55/76) in the daily-dose group, 81.5% (66/81) in the 1,200-mg-single-dose group, and 77.5% (55/71) in the infrequent-dose group. In patients with MRSA at baseline, the cure rates were 78.3% (18/23), 73.0% (27/37), and 87.0% (20/23) in the daily-, 1,200-mg-single-, and infrequent-dose groups, respectively; however, the study was not powered to assess outcomes in the MRSA subpopulation, and given the heterogeneity of the types of infection and the small sample size, these do not suggest any true differences in efficacy rates for these pathogens. The frequencies of adverse events were similar among treatment groups. The results of this study show that single- and infrequent-dosing schedules of oritavancin were as efficacious as daily administration and had a similar safety profile in treating cSSSI caused by Gram-positive pathogens, including MRSA.

Dataset Information

Relationship between time-to-isolation and freeze duration: Computational modeling of dosing for Arctic Front Advance and Arctic Front Advance Pro cryoballoons.

Publications

Relationship between time-to-isolation and freeze duration: Computational modeling of dosing for Arctic Front Advance and Arctic Front Advance Pro cryoballoons.

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