Preload-independent mechanisms contribute to increased stroke volume following large volume saline infusion in normal volunteers: a prospective interventional study

INTRODUCTION: Resuscitation with saline is a standard initial response to hypotension or shock of almost any cause. Saline resuscitation is thought to generate an increase in cardiac output through a preload-dependent (increased end-diastolic volume) augmentation of stroke volume. We sought to confirm this to be the mechanism by which high-volume saline administration (comparable to that used in resuscitation of shock) results in improved cardiac output in normal healthy volunteers. METHODS: Using a standardized protocol, 24 healthy male (group 1) and 12 healthy mixed sex (group 2) volunteers were infused with 3 l normal (0.9%) saline over 3 hours in a prospective interventional study. Individuals were studied at baseline and following volume infusion using volumetric echocardiography (group 1) or a combination of pulmonary artery catheterization and radionuclide cineangiography (group 2). RESULTS: Saline infusion resulted in minor effects on heart rate and arterial pressures. Stroke volume index increased significantly (by approximately 15–25%; P < 0.0001). Biventricular end-diastolic volumes were only inconsistently increased, whereas end-systolic volumes decreased almost uniformly. Decreased end-systolic volume contributed as much as 40–90% to the stroke volume index response. Indices of ventricular contractility including ejection fraction, ventricular stroke work and peak systolic pressure/end-systolic volume index ratio all increased significantly (minimum P < 0.01). CONCLUSION: The increase in stroke volume associated with high-volume saline infusion into normal individuals is not only mediated by an increase in end-diastolic volume, as standard teaching suggests, but also involves a consistent and substantial decrease in end-systolic volumes and increases in basic indices of cardiac contractility. This phenomenon may be consistent with either an increase in biventricular contractility or a decrease in afterload

Recent Development in Pulmonary Valve Replacement after Tetralogy of Fallot Repair:The Emergence of Hybrid Approaches

In the current era approximately 90% of infants born with tetralogy of Fallot (ToF) are expected to live beyond 40 years of age making it the fastest growing population amongst patients with congenital heart disease. One of the most common late consequences after repair of ToF, is pulmonary valve regurgitation (PVR). Significant PVR results in progressive dilatation and dysfunction of the right ventricle, decrease in exercise tolerance, arrhythmias, heart failure, and increased risk of sudden death. The conventional approach of dealing with this problem is to perform pulmonary valve replacement using cardiopulmonary bypass (CPB) and cardioplegic arrest. However, this approach is associated not only with long operative times but also side effects related to the use of CPB. Development of percutaneous approaches to valve disease is one of the most exciting areas of research and clinical innovation in cardiovascular research. The main development has been that of transcatheter pulmonary valve replacement for the rehabilitation of conduits between the right ventricle and pulmonary artery in patients after surgery for ToF. However, with the percutaneous technique, a limited size of prosthesis can be inserted. Moreover, the technique does not offer the opportunity of treating additional defects that are frequently associated with severe PR, such as pulmonary artery dilatation, and it cannot be used in the significantly dilated native right ventricular outlet tract (RVOT). The advent of the hybrid surgical options for treating cardiac disease has integrated the techniques of interventional cardiology with the techniques of cardiac surgery to provide a form of therapy that combines the respective strengths of both fields.In this review, we present and compare recent advances in procedures to replace the pulmonary valve in patients with ToF presenting with severe PVR and dilated RVOT

Management of Patients With Patent Foramen Ovale and Stroke: A National Survey of Interventional Cardiologists and Vascular Neurologists

Background Results from multiple clinical trials support patent foramen ovale closure after cryptogenic stroke in select patients, but it remains unclear how new data and updated professional society guidelines have impacted clinical practice. Here, we aimed to compare how stroke neurologists and interventional cardiologists approach patients with cryptogenic stroke with patent foramen ovale and how critical anatomic and clinical factors influence decision making. Methods and Results An electronic survey was administered to 1556 vascular neurologists and 1057 interventional cardiologists throughout the United States. The survey addressed factors such as patient age, preclosure workup, and postclosure antithrombotics. Clinical vignettes highlighted critical variables and used a 5‐point Likert scale to assess the providers' level of support for closure. There were 491 survey responses received from 301 (of 1556) vascular neurologists and 190 (of 1057) interventional cardiologists, with an overall response rate of 19%. Vascular neurologists were more likely to recommend against closure on the basis of older age (P<0.001). Interventional cardiologists are more supportive of closure across a range of clinical vignettes, including a very carefully selected patient with cryptogenic stroke (P<0.001), a patient with a high‐risk alternative stroke cause (P<0.001), and a range of cases highlighting clinical variables where data are lacking. The majority of interventionalists (88%) seek neurology consultation before pursuing patent foramen ovale closure. Conclusions lnterventional cardiologists are more likely than vascular neurologists to support patent foramen ovale closure across a range of situations. This emphasizes the importance of collaboration and shared decision making, but also reveals an opportunity for professional society educational outreach

Clinicians' Approach to Patent Foramen Ovale Closure after Stroke: Comparing Cardiologists and Neurologists

Background Evidence from randomized trials and updated professional society guidelines supports patent foramen ovale (PFO) closure after cryptogenic stroke in select patients. It is unclear how this has been integrated into real‐world practice, so we aimed to compare practice patterns between cardiologists and neurologists. Methods and Results In March of 2021, a survey of cardiologists and neurologists who work or previously trained at the University of Pennsylvania Health System assessed practice preferences with respect to PFO closure after stroke. Clinical vignettes isolated specific variables of interest and used a 5‐point Likert scale to assess the level of support for PFO closure. Stroke neurologists and interventional cardiologists were compared by Wilcoxon‐Mann–Whitney tests. Secondarily, Kruskal–Wallis tests compared stroke neurologists, general neurologists, interventional cardiologists, and general cardiologists. We received 106 responses from 182 survey recipients (31/31 stroke neurologists, 38/46 interventional cardiologists, 20/30 general neurologists, and 17/77 general cardiologists). A similar proportion of stroke neurologists and interventional cardiologists favored PFO closure in a young patient with cryptogenic stroke, 88% and 87%, respectively (P=0.54). Interventionalists were more likely than stroke neurologists to support closure in the context of an alternative high‐risk stroke mechanism, 14% and 0%, respectively (P=0.003). Stroke neurologists were more likely to oppose closure on the basis of older age (P=0.01). Conclusions There are key differences between how neurologists and cardiologists approach PFO closure after stroke, particularly when interpreting the stroke etiology and when considering closure beyond the scope of prior trials; this underscores the importance of collaboration between cardiologists and neurologists