Mean Arterial Pressure to Central Venous Pressure Ratio: A Novel Marker for Right Ventricular Failure After Left Ventricular Assist Device Placement

MEAN ARTERIAL PRESSURE/NOREPINEPHRINE EQUIVALENT DOSE INDEX AS AN EARLY MEASURE FOR MORTALITY RISK IN PATIENTS WITH SHOCK ON VASOPRESSORS

ABSTRACT

Purpose: We aimed to investigate the association between the early mean arterial pressure (MAP)/norepinephrine equivalent dose (NEQ) index and mortality risk in patients with shock on vasopressors and further identify the breakpoint value of the MAP/NEQ index for high mortality risk. Methods: Based on the Medical Information Mart for Intensive Care IV database, we conducted a retrospective cohort study involving 19,539 eligible intensive care unit records assigned to three groups (first tertile, second tertile, and third tertile) by different MAP/NEQ indexes within 24 h of intensive care unit admission. The study outcomes were 7-, 14-, 21-, and 28-day mortality. A Cox model was used to examine the risk of mortality following different MAP/NEQ indexes. The receiving operating characteristic curve was used to evaluate the predictive ability of the MAP/NEQ index. The restricted cubic spline was applied to fit the flexible correlation between the MAP/NEQ index and risk of mortality, and segmented regression was further used to identify the breakpoint value of the MAP/NEQ index for high mortality risk. Results: Multivariate Cox analysis showed that a high MAP/NEQ index was independently associated with decreased mortality risks. The areas under the receiving operating characteristic curve of the MAP/NEQ index for different mortality outcomes were nearly 0.7. The MAP/NEQ index showed an L-shaped association with mortality outcomes or mortality risks. Exploration of the breakpoint value of the MAP/NEQ index suggested that a MAP/NEQ index less than 183 might be associated with a significantly increased mortality risk. Conclusions: An early low MAP/NEQ index was indicative of poor prognosis in patients with shock on vasopressors.

Prediction, prevention, and management of right ventricular failure after left ventricular assist device implantation: A comprehensive review

Left ventricular assist devices (LVADs) are increasingly common across the heart failure population. Right ventricular failure (RVF) is a feared complication that can occur in the early post-operative phase or during the outpatient follow-up. Multiple tools are available to the clinician to carefully estimate the individual risk of developing RVF after LVAD implantation. This review will provide a comprehensive overview of available tools for RVF prognostication, including patient-specific and right ventricle (RV)-specific echocardiographic and hemodynamic parameters, to provide guidance in patient selection during LVAD candidacy. We also offer a multidisciplinary approach to the management of early RVF, including indications and management of right ventricular assist devices in this setting to provide tools that help managing the failing RV.

Intensive care management of right ventricular failure and pulmonary hypertension crises

Pulmonary hypertension (PH), an often unrelenting disease that carries with it significant morbidity and mortality, affects not only the pulmonary vasculature but, in turn, the right ventricle as well. The survival of patients with PH is closely related to the right ventricular function. Therefore, having an understanding of how to manage right ventricular failure (RVF) and acute pulmonary hypertensive crises is imperative for clinicians who encounter these patients. This review addresses the management of these patients in detail, addressing: (a) the pathophysiology of RVF, (b) intensive care monitoring of these patients in the intensive care unit, (c) imaging of the right ventricle, (d) intubation and mechanical ventilation, (e) inotrope and vasopressor selection, (f) pulmonary vasodilator use, (g) interventional and surgical procedures for the acutely failing right ventricle, and (h) mechanical support for RVF.

Right Ventricular Failure Post-Implantation of Left Ventricular Assist Device: Prevalence, Pathophysiology, and Predictors

Despite advances in left ventricular assist device (LVAD) technology, right ventricular failure (RVF) continues to be a complication after implantation. Most patients undergoing LVAD implantation have underlying right ventricular (RV) dysfunction (either as a result of prolonged LV failure or systemic disorders) that becomes decompensated post-implantation. Additional insults include intra-operative factors or a sudden increase in preload in the setting of increased cardiac output. The current literature estimates post-LVAD RVF from 3.9% to 53% using a diverse set of definitions. A few of the risk factors that have been identified include markers of cardiogenic shock (e.g., dependence on inotropes and Interagency Registry for Mechanically Assisted Circulatory Support profiles) as well as evidence of cardiorenal or cardiohepatic syndromes. Several studies have devised multivariable risk scores; however, their performance has been limited. A new functional assessment of RVF and a novel hepatic marker that describe cholestatic properties of congestive hepatopathy may provide additional predictive value. Furthermore, future studies can help better understand the relationship between pulmonary hypertension and post-LVAD RVF. To achieve our ultimate goal-to prevent and effectively manage RVF post-LVAD-we must start with a better understanding of the risk factors and pathophysiology. Future research on the different etiologies of RVF-ranging from acute post-surgical complication to late-onset RV cardiomyopathy-will help standardize definitions and tailor therapies appropriately.

Comparative Analysis of Established Risk Scores and Novel Hemodynamic Metrics in Predicting Right Ventricular Failure in Left Ventricular Assist Device Patients

BACKGROUND

Right ventricular failure (RVF) portends poor outcomes after left ventricular assist device (LVAD) implantation. Although numerous RVF predictive models have been developed, there are few independent comparative analyses of these risk models.

METHODS AND RESULTS

RVF was defined as use of inotropes for >14 days, inhaled pulmonary vasodilators for >48 hours or unplanned right ventricular mechanical support postoperatively during the index hospitalization. Risk models were evaluated for the primary outcome of RVF by means of logistic regression and receiver operating characteristic curves. Among 93 LVAD patients with complete data from 2011 to 2016, the Michigan RVF score (C = 0.74 [95% CI 0.61-0.87]; P = .0004) was the only risk model to demonstrate significant discrimination for RVF, compared with newer risk scores (Utah, Pitt, EuroMACS). Among individual hemodynamic/echocardiographic metrics, preoperative right ventricular dysfunction (C = 0.72 [95% CI 0.58-0.85]; P = .0022) also demonstrated significant discrimination of RVF. The Michigan RVF score was also the best predictor of in-hospital mortality (C = 0.67 [95% CI 0.52-0.83]; P = .0319) and 3-year survival (Kaplan-Meier log-rank 0.0135).

CONCLUSIONS

In external validation analysis, the more established Michigan RVF score-which emphasizes preoperative hemodynamic instability and target end-organ dysfunction-performed best, albeit modestly, in predicting RVF and demonstrated association with in-hospital and long-term mortality.

Clinical implications of hemodynamic assessment during left ventricular assist device therapy

Left ventricular assist devices (LVADs) significantly improve outcomes of advanced heart failure patients. However, patients continue to have high readmission rates due to complications ranging from bleeding, thrombosis, heart failure, and infection. Considering that the hallmark benefit of LVAD therapy is improvement in hemodynamics (cardiac unloading and increased cardiac output), hemodynamic assessment on LVAD support is key to better understand these difficult complications and may serve as a tool to resolving them. In this review, we will discuss the hemodynamic changes following LVAD implantation, and the implications and prognostic impact of hemodynamic optimization on outcomes and complications.