Transcatheter Left Atrial Appendage Exclusion: Preclinical and Early Clinical Results With the Laminar Device

BACKGROUND

The Laminar device rotates and closes the left atrial appendage (LAA) using an integrated ball and lock that excludes and eliminates the LAA pouch. There is a low device surface area, minimizing the risk of peridevice leak (PDL) and device-related thrombus (DRT) formation.

OBJECTIVES

This study evaluates the safety and efficacy of the Laminar LAA exclusion device in healthy animals and human subjects with nonvalvular atrial fibrillation at risk of ischemic stroke and systemic thromboembolism.

METHODS

The preclinical study implanted the Laminar device into canine subjects that underwent transesophageal echocardiography (TEE) and fluoroscopic evaluation, followed by necropsy and histological assessment at 45 and 150-days post-implant. The early clinical study implanted the device in human subjects, followed to 12 months postimplantation. Procedural success was defined as device implantation in the intended location without residual LAA leak >5 mm as seen by TEE. Safety endpoints included freedom from stroke, systemic embolism, pericardial effusion, or tamponade, life-threatening/major bleeding, or death.

RESULTS

The Laminar device was successfully implanted in 10 canines. In all animals at 45 days and 150 days, no PDL or DRT was found, and histological examination showed fully closed LAAs covered with neo-endocardium. The device was successfully implanted in 15 human subjects with no safety events out to 12 months postimplantation. All subjects had successful protocol-defined LAA closure without DRT at 45 days by TEE and computed tomography, which remained stable through 12 months' follow-up.

CONCLUSIONS

The preclinical and early clinical results demonstrate a promising safety and efficacy profile for the Laminar LAA exclusion device.

Tension Pneumomediastinum and Coronary Artery Thrombosis Following a Motorcycle Accident: A Case Report

INTRODUCTION

Tension pneumomediastinum and coronary artery thrombosis (CAT) secondary to blunt polytrauma are, rare yet have the potential for serious complication.

CASE REPORT

A 40-year-old man presented to the emergency department following a motorcycle accident. He was found to have multiple orthopedic injuries, pneumothorax, and pneumomediastinum. An electrocardiogram showed myocardial infarction. He developed obstructive shock physiology that resolved with mediastinal percutaneous needle drainage. Subsequent coronary angiography revealed acute thrombosis of the left circumflex artery.

CONCLUSION

This is a rare case of traumatic tension pneumomediastinum associated with coronary artery thrombosis requiring coronary stenting. Emergency physicians should be mindful of CAT in the setting of blunt chest injury.

Transcatheter Left Atrial Appendage Closure

Atrial fibrillation is the most common arrhythmia worldwide, placing a large population at risk for potentially disabling ischemic strokes, yet an estimated 50% of eligible patients cannot tolerate or are contraindicated to receive oral anticoagulation. Within the last 15 years, transcatheter options for left atrial appendage closure (LAAC) have provided a valuable alternative to chronic oral anticoagulation for reducing risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. With newer generation devices such as Watchman FLX and Amulet gaining approval from the US Food and Drug Administration in recent years, several large clinical trials have demonstrated the safety and efficacy of transcatheter LAAC in a population intolerant to systemic anticoagulation. In this contemporary review, we discuss the indications for transcatheter LAAC and the evidence evaluating the use of various device therapies currently available or in development. We also examine current unmet challenges in intraprocedural imaging and controversies in postimplantation antithrombotic regimens. Several ongoing seminal trials are hoping to clarify the role of transcatheter LAAC as a safe, first-line option for all patients with nonvalvular atrial fibrillation.

Attitudes on cost-effectiveness and equity: a cross-sectional study examining the viewpoints of medical professionals

OBJECTIVE

To determine the attitudes of physicians and trainees in regard to the roles of both cost-effectiveness and equity in clinical decision making.

DESIGN

In this cross-sectional study, electronic surveys containing a hypothetical decision-making scenario were sent to medical professionals to select between two colon cancer screening tests for a population.

SETTING

Three Greater Boston academic medical institutions: Tufts University School of Medicine, Tufts Medical Centre and Lahey Hospital and Medical Centre.

PARTICIPANTS

819 medical students, 497 residents-in-training and 671 practising physicians were contacted electronically using institutional and organisational directories.

MAIN OUTCOMES AND MEASURES

Stratified opinions of medical providers and trainee subgroups regarding cost-effectiveness and equity.

RESULTS

A total of 881 respondents comprising 512 medical students, 133 medical residents-in-training and 236 practising physicians completed the survey (total response rate 44.3%). Thirty-six per cent of medical students, 44% of residents-in-training and 53% of practising physicians favoured the less effective and more equitable screening test. Residents-in-training (OR 1.49, CI 1.01 to 2.21; p=0.044) and practising physicians (OR 2.12, CI 1.54 to 2.92; p<0.001) were more likely to favour the equitable option compared with medical students. Moreover, female responders across all three cohorts favoured the more equitable screening test to a greater degree than did male responders (OR 1.70, CI 1.29 to 2.24; p<0.001).

CONCLUSIONS

Cost-effectiveness analysis does not accurately reflect the importance that medical professionals place on equity. Among medical professionals, practising physicians appear to be more egalitarian than residents-in-training, while medical students appear to be most utilitarian and cost-effective. Meanwhile, female respondents in all three cohorts favoured the more equitable option to a greater degree than their male counterparts. Healthcare policies that trade off equity in favour of cost-effectiveness may be unacceptable to many medical professionals, especially practising physicians and women.