Novel robotic TCD ultrasound with bubbles versus standard care to detect right to left shunt: Study methods.

Background And Purpose: Right to left shunt (RLS), from patent foramen ovale (PFO) or elsewhere, is a recognized risk factor for stroke. Current standard of care for RLS diagnosis includes transthoracic echocardiography (TTE) which is insensitive, transesophageal echocardiography (TEE) which is invasive, and transcranial Doppler (TCD) which has excellent sensitivity and specificity for RLS but is heavily operator dependent and expertise is scarce. The purpose of this study was to evaluate the RLS detection rate of a novel robotic-assisted TCD (ra-TCD) to standard of care diagnostic techniques, including TTE, TEE, and TCD.

Assessing Cerebrovascular Hemodynamics Using Transcranial Doppler in Patients with Mechanical Circulatory Support Devices.

Background And Purpose: Mechanical circulatory support (MCS) devices are commonly used in heart failure patients. These devices carry risk for presumably embolic and additionally hemorrhagic stroke. Alterations in blood flow play a key role in stroke pathophysiology, and we aimed to learn more about hemodynamic compromise.

Cerebral Pulsatility Index Is Elevated in Patients with Elevated Right Atrial Pressure.

Background And Purpose: Extracerebral venous congestion can precipitate intracranial hypertension due to obstruction of cerebral blood outflow. Conditions that increase right atrial pressure, such as hypervolemia, are thought to increase resistance to jugular venous outflow and contribute to cerebro-venous congestion. Cerebral pulsatility index (CPI) is considered a surrogate marker of distal cerebrovascular resistance and is elevated with intracranial hypertension.

Paradoxical cerebrovascular hemodynamic changes with nicardipine.

OBJECTIVE Intravenous nicardipine is commonly used for blood pressure reduction in patients with acute stroke. However, few studies have described its effects on cerebrovascular hemodynamics as measured by transcranial Doppler (TCD) waveform analysis and pulsatility index (PI). In this study, the authors report examples of a consistent but paradoxical finding associated with nicardipine that suggests intracranial vasoconstriction, contrary to what is expected from a vasodilator.

Transcranial Doppler Changes in Patients Treated with Extracorporeal Membrane Oxygenation.

Background: Transcranial Doppler (TCD) has significant implications for neurovascular assessment in patients being treated with venoarterial-extracorporeal membrane oxygenation (VA-ECMO). However, there have been no studies demonstrating the changes in pulsatility indices (PIs) seen in these patients. Nonpulsatile waveforms are seen during on-pump coronary artery bypass graft, but low or low-normal PIs have never been reported.

Cerebral blood flow velocity and vasomotor reactivity during autonomic challenges in heart failure.

Background: Significant alterations in autonomic nervous system (ANS) function, vasomotor reactivity, and cerebral blood flow may develop from damage to brain ANS regulatory areas in heart failure (HF). This preferentially right-sided injury occurs largely in autonomic structures perfused by the middle cerebral artery. Indications of altered, asymmetrical perfusion raise the potential for further neural damage.