Hemodynamic Ramp Tests in Patients With Left Ventricular Assist Devices

Abstract

Objectives: This study tested whether combined invasive hemodynamic and echocardiographic ramp tests can help optimize patient management.

Background: Guidelines for optimizing speed and medications in continuous flow ventricular assist device (cfLVAD) patients are mainly based on expert opinion.

Methods: Thirty-five cfLVAD patients (21 HeartMate II [Thoratec, Pleasanton, California] and 14 HVAD [HeartWare International, Framingham, Massachusetts]) underwent ramp tests with right heart catheterization (including central venous pressure [CVP], pulmonary artery pressure, pulmonary capillary wedge pressure [PCWP], and blood pressure) and echocardiography. Data were recorded at up to 9 speed settings. Speed changes were in steps of 400 revolutions per minute (RPM) for HeartMate II (8,000 to 12,000 RPM) and 100 RPM for HVAD (2,300 to 3,200 RPM) patients.

Results: Only 42.9% of patients had normal CVPs and PCWPs at their original RPM settings. Going from lowest to highest speeds, cardiac output improved by 0.16 ± 0.19 l/min/step (total change 1.28 ± 1.41 l/min) and PCWP decreased by 1.23 ± 0.85 mm Hg/step (total change 9.9 ± 6.5 mm Hg). CVP and systolic blood pressure did not change significantly with RPM. RPM were adjusted based on test results to achieve CVPs and PCWPs as close to normal limits as possible, which was feasible in 56% of patients. For the remainder, results indicated which type of medical management should be pursued.

Conclusions: Use of combined hemodynamic and echocardiographic ramp tests in patients provides objective means of optimizing RPM, and has the potential to guide medical management. It remains to be tested whether this strategy has a beneficial impact on quality of life or clinical outcomes.

Keywords: 3D echocardiography; hemodynamics; left ventricular assist device; ramp; unloading.