Atrial Fibrillation After Patent Foramen Ovale Closure: Incidence, Pathophysiology, and Management.

This comprehensive review explores the incidence, pathophysiology, and management of atrial fibrillation (AF) following percutaneous closure of patent foramen ovale (PFO). Although AF is considered a common adverse event post PFO closure, its incidence, estimated at <5%, varies based on monitoring methods. The review delves into the challenging task of precisely estimating AF incidence, given subclinical AF and diverse diagnostic approaches. Notably, a temporal pattern emerges, with peak incidence around the 14th day after closure and a subsequent decline after the 45th day, mimicking general population AF trends. The pathophysiological mechanisms behind post PFO closure AF remain elusive, with proposed factors including local irritation, device-related interference, tissue stretch, and nickel hypersensitivity. Management considerations encompass rhythm control, with flecainide showing promise, and anticoagulation tailored to individual risk profiles. The authors advocate for a personalized approach, weighing factors like age, comorbidities, and device characteristics. Notably, postclosure AF is generally considered benign, often resolving spontaneously within 45 days, minimizing thromboembolic risks. Further studies are required to refine understanding and provide evidence-based guidelines.

Management of patent foramen ovale; findings from a nationwide survey.

OBJECTIVES: Several clinical trials have provided evidence supporting the transcatheter closure of patent foramen ovale (PFO) in selected patients following a cryptogenic stroke. However, it remains unknown to what extent these guidelines have been implemented in everyday clinical practice and the familiarity of physicians from different specialties with PFO closure. The aim of our nationwide survey is to explore the implementation of transcatheter PFO occlusion in Greek clinical practice. MATERIALS AND METHODS: Attending level cardiologists, internal medicine physicians and neurologists involved in the management of PFO-related strokes working in Greece were invited to complete an online questionnaire. The questionnaire consisted of 19 questions and was designed to obtain comprehensive data on provider demographics, PFO characteristics, and specific clinical scenarios. RESULTS: A total of 51 physicians (56.9 % cardiologists, 25.5 % neurologists and 17.6 % internal medicine physicians) completed the survey, resulting in a response rate of 53 %. Cardiologists, internal medicine physicians and neurologists agree on several issues regarding PFO closure, such as PFO closure as first line treatment, management of patients with DVT or prior decompression sickness, and post-closure antithrombotic treatment, but different approaches were reported regarding closure in patients with thrombophilia treated with oral anticoagulation (p=0.012) and implantable loop recorder placement for atrial fibrillation exclusion (p=0.029 and p=0.020). CONCLUSIONS: Our findings show that cardiologists, internal medicine physicians and neurologists agree in numerous issues, but share different views in the management of patients with thrombophilia and rhythm monitoring duration. These results highlight the significance of collaboration among physicians from different medical specialties for achieving optimal results.

Aortic valve: anatomy and structure and the role of vasculature in the degenerative process.

Aortic valve stenosis is a degenerative disease affecting increasing number of individuals and characterised by thickening, calcification and fibrosis of the valve resulting in restricted valve motion. Degeneration of the aortic valve is no longer considered a passive deposition of calcium, but an active process that involves certain mechanisms, that is endothelial dysfunction, inflammation, increased oxidative stress, calcification, bone formation, lipid deposition, extracellular matrix (ECM) remodelling and neoangiogenesis. Accumulating evidence indicates an important role for neoangiogenesis (i.e. formation of new vessels) in the pathogenesis of aortic valve stenosis. The normal aortic valve is generally an avascular tissue supplied with oxygen and nutrients via diffusion from the circulating blood. In contrast, presence of intrinsic micro-vasculature has been demonstrated in stenotic and calcified valves. Importantly, presence and density of neovessels have been associated with inflammation, calcification and bone formation. It remains unclear whether neoangiogenesis is a compensatory mechanism aiming to counteract hypoxia and increased metabolic demands of the thickened tissue or represents an active contributor to disease progression. Data extracted mainly from animal studies are supportive of a direct detrimental effect of neoangiogenesis, however, robust evidence from human studies is lacking. Thus, there is inadequate knowledge to assess whether neoangiogenesis could serve as a future therapeutic target for a disease that no effective medical therapy exists. In this review, we present basic aspects of anatomy and structure of the normal and stenotic aortic valve and we focus on the role of valve vasculature in the natural course of valve calcification and stenosis.

Catheter based inhibition of arterial calcification by bisphosphonates in an experimental atherosclerotic rabbit animal model.

BACKGROUND: Vascular calcification is an active process, sharing common molecular mechanisms with bone formation. Bisphosphonates are components, which inhibit calcification. The aim of the present study was to evaluate the safety and effectiveness of local delivery of the bisphosphonate zoledronate on inhibition of calcium formation in the arterial wall in an experimental animal model. METHODS: Sixteen New Zealand rabbits were placed on vitamin D enriched atherogenic diet for 3 weeks. Subsequently, all animals underwent angiography of abdominal aorta and common iliac arteries. A mixture containing 500 µg/l zoledronate was delivered on the vascular wall of the target iliac artery, using a dedicated balloon catheter. A placebo mixture was administered on the contralateral iliac artery of each animal, which was used as control. At 28 days all animals were sacrificed. Histologic sections of each common iliac artery were stained with hematoxylin-eosin and von Kossa. Computer-assisted histomorphometry was performed for the calcium content quantification of each section from the target and the control iliac artery. RESULTS: In all animals the local delivery of zoledronate and placebo mixtures was successful and uncomplicated. The mean percentage of the calcium content of the media was higher in the control artery segments compared to the target (2.66 ± 0.73 versus 1.08 ± 0.62 % of the area of the media, p<0.01). CONCLUSIONS: Inhibition of vascular calcification by local catheter-based delivery of bisphosphonate zolendronic acid is effective without evident short-term complications. These finding and its potential clinical implication remain to be confirmed in human studies.