Acute changes of left ventricular hemodynamics and function during percutaneous coronary intervention in patients with unprotected left main coronary artery disease

Outcomes of a modified, low-cost, veno-arterial extracorporeal membrane oxygenation (V-A ECMO) for elective, periprocedural support of high-risk percutaneous cardiac interventions: An experience from a latinamerican center

INTRODUCTION

High-risk procedures in interventional cardiology include a wide spectrum of clinical and anatomical scenarios related to a higher periprocedural morbidity and mortality. The prophylactic use of short-term mechanical circulatory support (ST-MCS) may improve both the safety and efficacy of the intervention by leading to more stable procedural hemodynamics. However, the significant costs may limit its use in resource constrained settings. To overcome this limitation, we ideated a modified, low-cost, veno-arterial extracorporeal membrane oxygenator (V-A ECMO) setup.

METHODS

We conducted an observational prospective study including all patients undergoing a high-risk interventional cardiology procedure at our institution under prophylactic ST-MCS using a modified, low-cost version of V-A ECMO, where some components of the standard V-A ECMO circuit were replaced by supplies used for cardiac surgical cardiopulmonary bypass, achieving a cost reduction of 72%. We assessed in-hospital and mid-term outcomes, including procedural success, post-procedure complications and mortality.

RESULTS

Between March 2016 and December 2021, ten patients underwent high-risk IC procedures with prophylactic use of V-A ECMO. Isolated percutaneous intervention (PCI) was performed in six patients, isolated transcatheter aortic valve replacement (TAVR) in two, and a combined procedure (PCI + TAVR) in two. Mean ejection fraction was 34% (range 20-64%). Mean STS PROM was 16.2% (range 9.5-35.8%) and mean EuroScore was 23.7% (range 1.5-60%). The planned intervention was successfully performed in all cases. There were no reports of V-A ECMO malfunction. In nine patients the VA-ECMO was withdrawn immediately after the procedure but one patient required extended - 24 h - support with no significant issues. One patient experienced a periprocedural myocardial infarction and another developed a femoral pseudoaneurysm. In-hospital and 30-day survival were 100%, and 1-year survival was 80%.

CONCLUSIONS

High-risk procedures in interventional cardiology can be successfully performed under prophylactic ST-MCS using a modified, low-cost V-A ECMO, suitable for limited-resource settings.

Molecular and Mechanical Mechanisms Regulating Ductus Arteriosus Closure in Preterm Infants

Failure of ductus arteriosus closure after preterm birth is associated with significant morbidities. Ductal closure requires and is regulated by a complex interplay of molecular and mechanical mechanisms with underlying genetic factors. In utero patency of the ductus is maintained by low oxygen tension, high levels of prostaglandins, nitric oxide and carbon monoxide. After birth, ductal closure occurs first by functional closure, followed by anatomical remodeling. High oxygen tension and decreased prostaglandin levels mediated by numerous factors including potassium channels, endothelin-1, isoprostanes lead to the contraction of the ductus. Bradykinin and corticosteroids also induce ductal constriction by attenuating the sensitivity of the ductus to PGE2. Smooth muscle cells of the ductus can sense oxygen through a mitochondrial network by the role of Rho-kinase pathway which ends up with increased intracellular calcium levels and contraction of myosin light chains. Anatomical closure of the ductus is also complex with various mechanisms such as migration and proliferation of smooth muscle cells, extracellular matrix production, endothelial cell proliferation which mediate cushion formation with the interaction of blood cells. Regulation of vessel walls is affected by retinoic acid, TGF-β1, notch signaling, hyaluronan, fibronectin, chondroitin sulfate, elastin, and vascular endothelial cell growth factor (VEGF). Formation of the platelet plug facilitates luminal remodeling by the obstruction of the constricted ductal lumen. Vasa vasorum are more pronounced in the term ductus but are less active in the preterm ductus. More than 100 genes are effective in the prostaglandin pathway or in vascular smooth muscle development and structure may affect the patency of ductus. Hemodynamic changes after birth including fluid load and flow characteristics as well as shear forces within the ductus also stimulate closure. Current pharmacological treatment for the closure of a patent ductus is based on the blockage of the prostaglandin pathway mainly through COX or POX inhibition, albeit with some limitations and side effects. Further research for new agents aiming ductal closure should focus on a clear understanding of vascular biology of the ductus.

When the Complex Meets the High-Risk: Mechanical Cardiac Support Devices and Percutaneous Coronary Interventions in Severe Coronary Artery Disease

Coronary artery disease (CAD) remains a leading cause of mortality and morbidity worldwide. Few practice guidelines directly address the issue of revascularization in patients with CAD at higher risk of periprocedural complications. It remains a challenge to appropriately identify the subset of patients with CAD who will require short-term use of mechanical cardiocirculatory support devices (MCSDs) when high-risk (HR) percutaneous coronary intervention (PCI) is required. Issues of the complexity (coronary anatomy and high burden of comorbidities) and risk status (hemodynamic precarity or compromise) need to be considered when considering revascularization in patients. This review will focus on the evolving concept of protected PCI in patients with CAD, and how a balanced, integrated heart-team approach remains the path to optimal patient-centred care in the setting of HR-PCI supported with MCSD.

Fetal hemodymanic effects on ductus arteriosus development and influences on postnatal management in infants with ductal-dependent pulmonary blood flow

The ductus arteriosus (DA) has been studied since Galen. Initially after birth in neonates with obstruction to pulmonary blood flow, DA patency is integral to ensure output and oxygenation. While DA stenting dates back 25 years, there is emerging interest in better understanding how and when to utilize this strategy as an alternative to surgical shunt placement or ongoing prostaglandin administration. Understanding the normal fetal circulation and the perturbations that affect flow and oxygenation is integral to comprehending how normal DA anatomy and morphology may change and how this may influence technical and clinical considerations. In the normal human fetus the great majority of descending aorta circulation comes from the DA, whereas this is a small minority in pulmonary outflow lesions, resulting in size and angle abnormalities. Study of the DA morphology has previously sought to identify patients requiring early intervention and more novel classifications are contributing to knowledge of complications and increasing the likelihood of success. As well, optimal patient selection for aorto-pulmonary shunt vs DA stent remains unclear. This review seeks to convey how fetal circulation can affect the DA, how other clinical considerations such as neurocognitive development support these finding and influence management, and emphasize that the variability in the DA will affect suitability for stenting, which requires further study as guidelines and standards are developed.