The advent of LVADs marks a significant milestone in managing patients with advanced HF. Since their approval, LVAD implantation rates have steadily increased. Advances in technology, particularly the development of smaller, continuous-flow devices, have extended LVAD survival to match that of heart transplant at two years.

However, LVAD patients experience a high rate of complications and hospital readmissions post-implant. A thorough understanding of the unique physiology and hemodynamics of LVAD patients is essential to optimize device support and manage LVAD-related complications, with the aim of not only reducing morbidity and mortality but also enhancing quality of life and exercise capacity.

This consensus document reviews the specific requirements for invasive hemodynamic assessment (IHA) in LVAD patients and identifies clinical scenarios where IHA can be most beneficial for the healthcare provider managing these patients.

The authors emphasize thermodilution as the most reliable and reproducible method for cardiac output (CO) measurement, showing a closer correlation with the direct Fick method than the indirect Fick calculation. Additionally, they highlight the importance of adequate anticoagulation levels during the procedure. The consensus specifies that IHA holds particular value in the following scenarios for LVAD patients:

Optimizing LVAD Function. Determining the optimal pump speed for LVAD function requires individualized assessment that considers both the effective CO and left ventricular unloading (evaluated through pulmonary capillary wedge pressure [PCWP] and pulmonary pressure). Additionally, the document addresses ventricular interdependence (monitoring right ventricular [RV] end-diastolic pressure to prevent RV failure) while aiming for intermittent aortic valve opening and avoiding pulmonary decoupling. To optimize LVAD function, IHA is recommended at three months post-implant, using an invasive ramp study to determine the ideal level of LVAD support. This test involves gradually increasing LVAD speed from a minimum tolerated value to a maximum, identifying the speed that best improves the patient’s hemodynamics. A promising, albeit limited, method is adjusting LVAD function to match patient activity levels, pinpointing cases where ventricular unloading or CO during exercise are inadequate through IHA.

Identifying Causes of LVAD Dysfunction. Low-flow LVAD alarms are common, and non-invasive studies like echocardiography may fail to identify the cause. In such cases, it is crucial to determine whether the alarm is due to an issue with LV preload (e.g., hypovolemia, RV failure, cardiac tamponade) or an obstruction in LVAD flow (e.g., hypertension, outflow graft twist or obstruction, or LVAD thrombosis). For hypovolemia, reduced pressures in the right atrium, pulmonary artery, and PCWP are expected, whereas cardiac tamponade or RV failure would show increased right atrial pressure with a low PCWP. If LVAD flow is obstructed, PCWP will rise.

Assessment of Pulmonary Vascular Resistance (PVR). A significant proportion of patients receiving LVADs as a bridge to transplant have severe combined pre- and post-capillary pulmonary hypertension. The impact of LVADs on PVR is seen early; however, reassessment of PVR is recommended between 3-6 months post-implant to capture any significant decrease, as further changes beyond six months are rare.

Determining Candidates for LVAD Weaning Due to Cardiac Function Recovery. IHA directly measures CO and PCWP response when LVAD support is reduced or briefly interrupted, determining whether the patient can tolerate discontinuation of the device.

COMMENTARY:
This document underscores the importance of invasive hemodynamic evaluation in LVAD-supported advanced HF patients. For years, cardiac surgeons and cardiologists have focused on pre-implant IHA, primarily to confirm low CO status and identify patients at high risk for RV failure post-implant—a critical factor in selecting optimal candidates. Improvements in candidate selection, technological advances, and better understanding of patient complications and their management have led to progressively improved post-implant survival rates. However, managing and optimizing LVAD patients remains complex. According to international records, only 30% of LVAD patients achieve optimal outcomes after one year: alive or transplanted, in NYHA class I or II, with no adverse events or fewer than three rehospitalizations per year. An LVAD patient is still considered an HF patient, which remains the main cause of hospital readmission.

Echocardiography remains a valid tool for routine monitoring of these patients; however, it is insufficient for in-depth assessment of specific clinical concerns. The utility of echocardiography is further limited with third-generation devices (e.g., HeartMate 3, HVAD), which distort LV geometry and cause leftward horizontal displacement of the LV compared to second-generation devices. Three-dimensional echocardiography likely offers more valuable information for third-generation devices, although implementing it in daily practice remains challenging.

Significant evidence shows that optimized LVAD support substantially reduces adverse events and enhances patients’ quality of life. This article highlights the applications and value of IHA in achieving better patient outcomes. Programs conducting post-implant IHA demonstrate that over 50% of discharged patients present elevated central venous or PCWP during follow-up IHA, presenting a substantial opportunity to optimize both LVAD support and HF medical management. The RAMP-IT-UP study found that patients monitored with IHA received more than twice the HF medication adjustments compared to those under standard follow-up, resulting in improved survival and fewer adverse events. Hemodynamic optimization correlates directly with lower HF readmissions and reduced hemocompatibility-related adverse events, including gastrointestinal bleeding, LVAD thrombosis, and stroke.

The 2023 guidelines from the International Society for Heart and Lung Transplantation for LVAD patients align with this document’s authors, identifying IHA as essential for comprehensive LVAD patient management, aiming to reduce morbidity and mortality and, in particular, to appropriately assess patients with persistent HF signs and symptoms. Implementing post-implant IHA across advanced HF programs offering LVAD therapy is recommended. Developing strategies to extract the most valuable information from IHA while minimizing patient risk remains a topic for further research. New advances, including remote pulmonary artery pressure monitoring and HF monitoring through implantable cardiac devices, hold great potential for the future.

REFERENCE:
Rodenas-Alesina E, Brahmbhatt DH, Mak S, Ross HJ, Luk A, Rao V, et al. Value of Invasive Hemodynamic Assessments in Patients Supported by Continuous-Flow Left Ventricular Assist Devices. JACC Heart Fail. 2024; 12(1):16-27. doi: 10.1016/j.jchf.2023.08.019.