Recurrent orthostatic syncope due to left atrial and left ventricular collapse after a continuous-flow left ventricular assist device implantation

A Computational Hemodynamics Approach to Left Ventricular Assist Device (LVAD) Optimization Validated in a Large Patient Cohort

With increasing use of left ventricular assist devices (LVAD) it is critical to devise strategies to optimize LVAD speed while controlling mean arterial pressure (MAP) and flow according to patient physiology. The complex interdependency between LVAD speed, MAP, and flow frequently makes optimization difficult under clinical conditions. We propose a method to guide this procedure in silico, narrowing the conditions to test clinically. A computational model of the circulatory network that simulates HF and LVAD support, incorporating LVAD pressure-flow curves was applied retrospectively to anonymized patient hemodynamics data from the University of Washington Medical Center. MAP management on 61 patient-specific computational models with a target of 70 mm Hg, resulting flow for a given LVAD speed was analyzed, and compared to a target output of 5 L/min. Before performing virtual MAP management, 51% had a MAP>70 mm Hg and CO>5 L/min, and 33% had a MAP>70 mm Hg and CO<5 L/min. After changing systemic resistance to meet the MAP target (without adjusting LVAD speed), 84% of cases resulted in CO higher than 5 L/min, with a median CO of 6.79 L/min, using the computational predictive model. Blood pressure management alone is insufficient in meeting both MAP and CO targets, due to the risk of hypervolemia, and requires appropriate LVAD speed optimization to achieve both targets, while preserving right heart health. Such computational tools can narrow down conditions to be tested for each patient, providing significant insight into the pump-patient interplay. LVAD hemodynamic optimization has the potential to reduce complications and improve outcomes.

Hemodynamic Assessment of Dual Obstructive Left Ventricular Assist Device Lesions

Obstructive left ventricular assist device (LVAD) lesions are uncommon but are being increasingly recognized, particularly with the increased use of advanced imaging modalities. While heart failure symptoms and LVAD power fluctuations have a broad differential, obstructive lesions in the LVAD circuit should be considered. We present a unique case of a patient supported on HeartWare HVAD (Medtronic Inc., Dublin, Ireland) therapy, who experienced postural dizziness with objective orthostatic hypotension and occasional ventricular tachycardia. With fluctuations in LVAD flow and power, a CT scan with three-dimensional reconstruction was obtained showing outflow graft kinking. The patient was brought to the cardiac catheterization laboratory for investigation and consideration of outflow graft intervention. However, intracardiac echocardiography revealed the presence of an inflow cannula obstruction with position changes and catheter interrogation involving the outflow cannula suggestive of a gradient across the kinked area as an unlikely cause for the presentation. This case highlights the importance of a thorough interrogation for obstructive lesions in the setting of heart failure symptoms, particularly postural symptoms, in a patient on LVAD therapy, even when not identified on routine echocardiography.

Surface mapping demonstrates compatibility of implantable loop monitor with a continuous-flow left ventricular assist device

Syncope in patients with continuous‐flow left ventricular assist device may be associated with arrhythmia and difficult to determine without an implantable cardioverter defibrillator. We present a patient with continuous‐flow left ventricular assist device, no implantable cardioverter defibrillator, and recurrent syncope. An implantable loop recorder was successfully implanted with surface mapping without noise interference.

Orthostatic Syncope from Compromised Flow after Heartware HVAD by Lateral Thoracotomy: Potential Role of Dynamic Echocardiographic Testing for Cannula Assessment

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Orthostatic syncope after left ventricular assist device (LVAD) implantation is uncommon.

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New LVAD implantation techniques, such as a lateral thoractomy approach, may impact the cannula position and flows.

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Echocardiography is a valuable tool in LVAD patients and can be used to assess the inflow cannula position and flow characteristics.

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We report a case using echocardiography with orthostatic testing to diagnose abnormal flow states from cannula position and patient interaction.

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Dynamic echocardiography can enhance cannula assessment and improve diagnostic testing in LVAD patients with mechanical flow concerns.

Mechanical circulatory assist devices: a primer for critical care and emergency physicians

Mechanical circulatory assist devices are now commonly used in the treatment of severe heart failure as bridges to cardiac transplant, as destination therapy for patients who are not transplant candidates, and as bridges to recovery and “decision-making”. These devices, which can be used to support the left or right ventricles or both, restore circulation to the tissues, thereby improving organ function. Left ventricular assist devices (LVADs) are the most common support devices. To care for patients with these devices, health care providers in emergency departments (EDs) and intensive care units (ICUs) need to understand the physiology of the devices, the vocabulary of mechanical support, the types of complications patients may have, diagnostic techniques, and decision-making regarding treatment. Patients with LVADs who come to the ED or are admitted to the ICU usually have nonspecific clinical symptoms, most commonly shortness of breath, hypotension, anemia, chest pain, syncope, hemoptysis, gastrointestinal bleeding, jaundice, fever, oliguria and hematuria, altered mental status, headache, seizure, and back pain. Other patients are seen for cardiac arrest, psychiatric issues, sequelae of noncardiac surgery, and trauma. Although most patients have LVADs, some may have biventricular support devices or total artificial hearts. Involving a team of cardiac surgeons, perfusion experts, and heart-failure physicians, as well as ED and ICU physicians and nurses, is critical for managing treatment for these patients and for successful outcomes. This review is designed for critical care providers who may be the first to see these patients in the ED or ICU.