Stephen H. Bailey

Low Accuracy of the HeartMate Risk Score for Predicting Mortality using the INTERMACS Registry Data.

Selection is a key determinant of clinical outcomes after left ventricular assist device (LVAD) placement in patients with end-stage heart failure. The HeartMate II risk score (HMRS) has been proposed to facilitate risk stratification and patient selection for continuous flow pumps. This study retrospectively assessed the performance of HMRS in predicting 90 day and 1 year mortality in patients within the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS). A total of 11,523 INTERMACS patients who received a continuous flow LVAD between 2010 and 2015 were retrospectively categorized per their calculated HMRS to predict their 90 day and 1 year risk of mortality. The performance of the score was evaluated by the area under curve (AUC) of the receiver operator characteristic. We also performed multiple regression analysis using variables from the HMRS calculation on the INTERMACS data. The HMRS model showed moderate discrimination for both 90 day and 1 year mortality prediction with AUCs of 61% and 59%, respectively. The predictions had similar accuracy irrespective of whether the pump was axial or centrifugal flow. Multivariable analysis using independent variables used in the original HMRS analysis revealed different set of variables to be predictive of 90 day mortality than those used to calculate HMRS. HMRS predicts both 90 day and 1 year mortality with poor discrimination when applied to a large cohort of LVAD patients. Newer risk prediction models are therefore needed to optimize the therapeutic application of LVAD therapy. Patient selection for appropriate use of LVADs is critical. Currently available risk stratification tools (HMRS) continue to be limited in their ability to accurately predict mortality after LVAD. This study highlights these limitations when applied to a large, comprehensive, multicenter database. HMRS predicts mortality with only modest discrimination when applied to a large cohort of LVAD patients. Better risk stratification tools are needed to optimize outcomes.

A parallel wire robot for epicardial interventions.

This paper describes the design and preliminary testing of a planar parallel wire robot that adheres to the surface of the beating heart and provides a stable platform for minimally invasive epicardial therapies. The device is deployed through a small subxiphoid skin incision and attaches to the heart using suction. This methodology obviates mechanical stabilization and lung deflation, which are typically required during minimally invasive beating-heart surgery. The prototype design involves three vacuum chambers connected by two flexible arms. The chambers adhere to the epicardium, forming the vertices of a triangular base structure. Three cables connect a movable end-effector head to the three bases; the cables then pass out of the body to external actuators. The surgical tool moves within the triangular workspace to perform injections, ablation, or other tasks on the beating heart. Tests in vitro and in vivo were conducted to demonstrate the capabilities of the system. Tests in vivo successfully demonstrated the ability to deploy through a subxiphoid incision, adhere to the surface of the beating heart, move the surgical tool head within the robots workspace, and perform injections into the myocardium.

A Bayesian Model to Predict Survival After Left Ventricular Assist Device Implantation

OBJECTIVESnThis study investigates the use of a Bayesian statistical models to predict survival at various time points in patients undergoing left ventricular assist device (LVAD) implantation.nnnBACKGROUNDnLVADs are being increasingly used in patients with end-stage heart failure. Appropriate patient selection continues to be key in optimizing post-LVAD outcomes.nnnMETHODSnData used for this study were derived from 10,277 adult patients from the INTERMACS (Inter-Agency Registry for Mechanically Assisted Circulatory Support) who had a primary LVAD implanted between January 2012 and December 2015. Risk for mortality was calculated retrospectively for various time points (1, 3, and 12 months) after LVAD implantation, using multiple pre-implantation variables. For each of these endpoints, a separate tree-augmented naïve Bayes model was constructed using the most predictive variables.nnnRESULTSnA set of 29, 26, and 31 pre-LVAD variables were found to be predictive at 1, 3, and 12 months, respectively. Predictors of 1-month mortality included low Inter-Agency Registry for Mechanically Assisted Circulatory Support profile, number of acute events in the 48 h before surgery, temporary mechanical circulatory support, and renal and hepatic dysfunction. Variables predicting 12-month mortality included advanced age, frailty, device strategy, and chronic renal disease. The accuracy of all Bayesian models was between 76% and 87%, with an area under the receiver operative characteristics curve of between 0.70 and 0.71.nnnCONCLUSIONSnA Bayesian prognostic model for predicting survival based on the comprehensive INTERMACS registryxa0provided highly accurate predictions of mortality based on pre-operative variables. These models may facilitatexa0clinical decision-making while screening candidates for LVAD therapy.

MITRAL STENOSIS SECONDARY TO HIGH-GRADE LIPOSARCOMA IN A YOUNG PREGNANT FEMALE

Undiagnosed mitral stenosis can manifest itself during pregnancy. Most commonly, the culprit is underlying rheumatic valve disease, however, other etiologies are possible. Prior to clinical decision-making, considerations are taken into account about the severity of the stenosis, the health of the

Successful treatment of acute left ventricular assist device thrombosis and cardiogenic shock with intraventricular thrombolysis and a tandem heart.

Management for continuous flow left ventricular assist device (LVAD) thrombosis often relies on speculation of individual clinical risk factors and integration of indirect evidence for device dysfunction. There are no comprehensive guidelines for treatment of this serious complication, and most of our current knowledge comes from anecdotal experience or observational study. More data on effective treatment, both with aggressive pharmacologic and device-based interventions, are needed for improving our understanding of mechanisms driving device thrombosis and for preventing future events. We present a case of LVAD thrombosis with emphasis on recognition and treatment of acute pump thrombosis, and discuss a potentially novel strategy using percutaneous mechanical circulatory support for pump salvage.

Challenges and Future Directions in Left Ventricular Assist Device Therapy

The clinical use of left ventricular assist devices (LVADs) in the growing epidemic of heart failure has improved quality of life and long-term survival for this otherwise devastating disease. The current generation of commercially available devices offers a smaller profile that simplifies surgical implantation, a design that optimizes blood flow characteristics, with less adverse events and improved durability than their predecessors. Despite this, the risk for adverse events remains significant, as do burdens for patients and their caregivers. Appropriate patient selection remains key to optimal LVAD outcomes.