Cardiac reserve is a globally used health indicator and prognostic tool that is used by clinicians and preclinical scientists. In physiology, we have a long-standing appreciation of how to assess systolic reserve but lack insight into sex differences and have no frame of reference for measuring diastolic reserve to certainty across cardiac techniques or the influence of sex. Here, we show that the primary means for assessing diastolic reserve is incorrect. Furthermore, we provided proof and clarity on how to correctly measure systolic and diastolic reserve capacities. We also highlight the imperative of sex differences to the measures of both systolic and diastolic reserves using several techniques (i.e., echocardiography, invasive hemodynamics, and Langendorff) in mice. 

Assessing systolic and diastolic reserves in male and female mice

Right heart failure (RHF) can occur as the result of an acute or chronic disease process and is a challenging clinical condition for surgeons and interventionalists to treat. RHF occurs in approximately 0.1% of patients after cardiac surgery, in 2–3% of patients following heart transplantation, and in up to 42% of patients after LVAD implantation. Regardless of the cause, RHF portends high morbidity and mortality and is associated with longer hospital stays and higher healthcare costs. The mainstays of traditional therapy for severe RHF have included pharmacological support, such as inotropes and vasopressors, and surgical right ventricular (RV) assist devices. However, in recent years catheter-based mechanical circulatory support (MCS) strategies have offered novel solutions for addressing RHF without the morbidity of open surgery. This manuscript will review the pathophysiology of RHF, including the molecular underpinnings, gross structural mechanisms, and hemodynamic consequences. The evolution of techniques for supporting the right ventricle will be explored, with a focus on various institutional experiences with percutaneous ventricular assist devices.

/pdf/supporting-the-forgotten-ventricle-the-evolution-of-3msblk8u.pdf

Supporting the “forgotten” ventricle: The evolution of percutaneous RVADs

Optimal, Early Postoperative Management of Cardiac Transplant and Durable Left Ventricular Assist Recipients.

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.

/pdf/prediction-prevention-and-management-of-right-ventricular-3emzurh4.pdf

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

In this issue of the Journal, Read and colleagues1 report the use of peak stroke volume index (SVI) during pre-procedure vasodilatory testing as a predictor of early right heart failure (RHF) after left ventricular assist device (LVAD) implantation. They retrospectively examine 70 patients from 3 institutions who underwent pre-implant nitroprusside vasodilator testing. Indications for pre-operative vasodilator testing were elevated pulmonary vascular resistance, pulmonary arterial wedge pressure, or systolic pulmonary artery pressure. 

Right heart failure after left ventricular assist device implantation - from prediction to action.

Early right heart failure (RHF) remains a major source of morbidity and mortality after left ventricular assist device (LVAD) implantation, yet efforts to predict early RHF have proven only modestly successful. Pharmacologic unloading of the left ventricle may be a risk stratification approach allowing for assessment of right ventricular and hemodynamic reserve.We performed a multicenter, retrospective analysis of patients who had undergone continuous-flow LVAD implantation from October 2011 to April 2020. Only those who underwent vasodilator testing with nitroprusside during their preimplant right heart catheterization were included (n = 70). Multivariable logistic regression was used to determine independent predictors of early RHF as defined by Mechanical Circulatory Support-Academic Research Consortium.Twenty-seven patients experienced post-LVAD early RHF (39%). Baseline clinical characteristics were similar between patients with and without RHF. Patients without RHF, however, achieved higher peak stroke volume index (SVI) (30.1 ± 8.8 vs 21.7 ± 7.4 mL/m2; p < 0.001; AUC: 0.78; optimal cut-point: 22.1 mL/m2) during nitroprusside administration. Multivariable analysis revealed that peak SVI was significantly associated with early RHF, demonstrating a 16% increase in risk of early RHF per 1 ml/m2 decrease in SVI. A follow up cohort of 10 consecutive patients from July 2020 to October 2021 resulted in all patients being categorized appropriately in regards to early RHF versus no RHF according to peak SVI.Peak SVI with nitroprusside administration was independently associated with post-LVAD early RHF while resting hemodynamics were not. Vasodilator testing may prove to be a strong risk stratification tool when assessing LVAD candidacy though additional prospective validation is needed. 

Nirmal Kumar Betchoo

Papers

Hemodynamic reserve predicts early right heart failure after LVAD implantation