Evaluation of a Health Care Performance Improvement Initiative to Facilitate Optimal Clinical Outcomes in Patients Receiving Ventricular Assist Device Support.

Background: Ventricular assist device (VAD) patients are at high risk for morbidities and mortality. One potentially beneficial component of the Joint Commission VAD Certification process is the requirement that individual VAD programs select 4 performance measures to improve and optimize patients' clinical outcomes.

Problem Statement: Review of patient data after our program's first certification visit in 2008 showed that, compared to national recommendations and published reports, our patients had suboptimal outcomes in 4 areas after device implantation: length of hospital stay, receipt of early (<48 hours) postsurgical physical therapy, driveline infection incidence, and adequacy of nutritional status (prealbumin ≥18 mg/dL).

Cross-comparisons of trending accuracies of continuous cardiac-output measurements: pulse contour analysis, bioreactance, and pulmonary-artery catheter.

We compared the similarity of cardiac-output (CO) estimates between available bolus thermodilution pulmonary-artery catheters (PAC), arterial pulse-contour analysis (LiDCOplus, FloTrac and PiCCOplus), and bioreactance (NICOM). Repetitive simultaneous estimates of CO obtained from the above devices were compared in 21 cardiac-surgery patients during the first 2 h post-surgery. Mean and absolute values for CO across the devices were compared by ANOVA, Bland-Altman, Pearson moment, and linear-regression analyses.

Monitoring patients with continuous-flow ventricular assist devices outside of the intensive care unit: novel challenges to bedside nursing.

Ventricular assist devices provide therapeutic options for patients with severe heart failure who have exhausted available medical therapies. With restoration of organ perfusion with ventricular assist devices, the heart failure resolves and quality of life and functional status improve. The current generation of continuous-flow devices present novel challenges to the clinical assessment of patients by substantially reducing or nearly eliminating any palpable pulse.

Bariatric surgery for a patient with a HeartMate II ventricular assist device for destination therapy.

A patient with a HeartMate II left ventricular assist device who had a body mass index of 52 needed gastric bypass surgery in order to qualify for a heart transplant. Unlike previous experience in which the surgery was performed at the implant hospital, the gastric bypass surgery in this case was performed at a bariatric center of excellence that was a separate facility from the implant hospital. The artificial heart program of the University of Pittsburgh Medical Center worked with the bariatric center of excellence in scheduling the gastric bypass surgery using a multidisciplinary team approach at 2 hospitals to coordinate safe, high-quality patient care in a unique situation.

Cross-comparison of cardiac output trending accuracy of LiDCO, PiCCO, FloTrac and pulmonary artery catheters.

Introduction: Although less invasive than pulmonary artery catheters (PACs), arterial pulse pressure analysis techniques for estimating cardiac output (CO) have not been simultaneously compared to PAC bolus thermodilution CO (COtd) or continuous CO (CCO) devices.

Methods: We compared the accuracy, bias and trending ability of LiDCO™, PiCCO™ and FloTrac™ with PACs (COtd, CCO) to simultaneously track CO in a prospective observational study in 17 postoperative cardiac surgery patients for the first 4 hours following intensive care unit admission. Fifty-five paired simultaneous quadruple CO measurements were made before and after therapeutic interventions (volume, vasopressor/dilator, and inotrope).

The effects of vasoactive drugs on pulse pressure and stroke volume variation in postoperative ventilated patients.

Introduction: Although pulse pressure variation (PPV) and stroke volume variation (SVV) during mechanical ventilation have been shown to predict preload responsiveness, the effect of vasoactive therapy on PPV and SVV is unknown.

Methods: Pulse pressure variation and SVV were measured continuously in 15 cardiac surgery patients for the first 4 postoperative hours. Pulse pressure variation was directly measured from the arterial pressure waveform, and both PPV and SVV were also calculated by LiDCO Plus (LiDCO Ltd, Cambridge, United Kingdom) before and after volume challenges or changes in vasoactive drug infusions done to sustain cardiovascular stability.

The Joint Commission's disease-specific care certification for destination therapy ventricular assist devices.

The Centers for Medicare and Medicaid Services announced that all hospitals implanting ventricular assist devices are required to have certification from the The Joint Commission for disease-specific care destination therapy with a ventricular assist device effective March 27, 2009, in order to receive Medicare reimbursement for services rendered to patients who have devices implanted for destination therapy. On February 23, 2007, The Joint Commission released the certification requirements for ventricular assist devices implanted for destination therapy in an 8-page document so that hospitals could prepare to meet the 2009 certification deadline. The Artificial Heart Program of the University of Pittsburgh Medical Center undertook a multidisciplinary project, under the guidance of the nurse coordinator, to prepare the hospital and program for a precertification survey by The Joint Commission for disease-specific destination therapy ventricular assist device certification.

Ability of pulse power, esophageal Doppler, and arterial pulse pressure to estimate rapid changes in stroke volume in humans.

Introduction: Measures of arterial pulse pressure variation and left ventricular stroke volume variation induced by positive-pressure breathing vary in proportion to preload responsiveness. However, the accuracy of commercially available devices to report dynamic left ventricular stroke volume variation has never been validated.

Methods: We compared the accuracy of measured arterial pulse pressure and estimated left ventricular stroke volume reported from two Food and Drug Administration-approved aortic flow monitoring devices, one using arterial pulse power (LiDCOplus) and the other esophageal Doppler monitor (HemoSonic).

Thresholded area over the curve of spectrometric tissue oxygen saturation as an indicator of volume resuscitability in porcine hemorrhagic shock.

Background: A rapid, reliable, and noninvasive functional measure of responsiveness to resuscitation in posttraumatic hemorrhagic shock could prove useful in guiding therapy, especially under circumstances such as the battlefield and civilian mass casualties. Tissue oxygen saturation (Sto2) is a promising candidate for this application. We therefore explored the value of peripheral muscle Sto2 in predicting systemic responsiveness to colloid volume resuscitation in a porcine model of hemorrhagic shock.

Effects of radial left ventricular dyssynchrony on cardiac performance using quantitative tissue Doppler radial strain imaging.

Our objective was to test the hypothesis that novel angle-corrected radial strain imaging can quantify left ventricular dyssynchrony associated with contractile impairment and improved with biventricular pacing. Eight open-chest dogs were studied by novel angle-corrected color-coded radial strain imaging and high-fidelity pressure-conductance catheters recording pressure-volume loops. Heart rate was controlled by right atrial pacing and all timing intervals were corrected by R-R interval (corrected interval = measured interval/(R-R interval)(1/2)).

Usefulness of angle corrected tissue Doppler to assess segmental left ventricular function during dobutamine stress echocardiography in patients with and without coronary artery disease.

The application of angle correction to tissue Doppler (TD) during dobutamine stress echocardiography (DSE) extends the application of TD to all left ventricular segments, improves the differentiation of abnormal from normal segmental responses to stress, and has promise to improve its clinical utility for objectively evaluating wall motion during DSE.

Influence of alterations in loading on mitral annular velocity by tissue Doppler echocardiography and its associated ability to predict filling pressures.

Study Objectives: Early diastolic mitral annular velocity (E') by tissue Doppler echocardiography (TD) has been reported to be a load-independent index of left ventricular (LV) diastolic function, allowing the early diastolic mitral inflow velocity (E)/E' ratio to be used clinically to predict LV filling pressures. However, preload independence of E' has remained controversial, and E/E' may not consistently be predictive of LV filling pressures. Our objectives were to test the hypotheses that E' is affected by preload, and that alterations of preload, afterload, and contractility also affect E/E'.

Quantification of radial mechanical dyssynchrony in patients with left bundle branch block and idiopathic dilated cardiomyopathy without conduction delay by tissue displacement imaging.

Cardiac resynchronization therapy has made assessment of cardiac dyssynchrony clinically important. To test the hypothesis that echocardiographic displacement imaging can quantify dyssynchrony, 22 patients with left bundle branch block (LBBB), 14 with idiopathic dilated cardiomyopathy (IDC) without electrical conduction delay, and 22 normal controls were studied using radial angle-corrected displacement imaging. Control subjects had coordinated wall movement, whereas patients with LBBB had dyssynchrony characterized by early inward anteroseptal movement and markedly delayed posterior, lateral, or inferior regions (157 +/- 99 ms; p <0.

The influence of hemodynamics and wall biomechanics on the thrombogenicity of vein segments perfused in vitro.

This study addresses the hypothesis that exposure to peripheral arterial (ART) or coronary (COR) hemodynamics and wall biomechanics affect platelet deposition on vein segments. Intact human saphenous vein (HSV) and porcine internal jugular vein (PIJV) segments were studied under venous (VEN), ART, and COR environments using in vitro perfusion systems. Wall shear stress (tau) and circumferential wall stress (sigma(theta)) were calculated for PIJV segments.

Non-invasive assessment of myocardial recovery on chronic left ventricular assist device: results associated with successful device removal.

Background: Myocardial recovery may occur in patients with heart failure who are receiving left ventricular assist-device support, but identification of candidates for device removal remains challenging. We hypothesized that on-line quantitative echocardiography during trials of decreased device support alone or in combination with exercise cardiopulmonary testing can assess cardiac recovery to predict successful device removal.

Methods: We studied 18 patients with severe heart failure, aged 45 +/- 19 years, who received 234 +/- 169 days of assist-device support as a bridge to transplantation.

Regional correlation by color-coded tissue Doppler to quantify improvements in mechanical left ventricular synchrony after biventricular pacing therapy.

Cardiac resynchronization therapy (CRT) can improve cardiac function in patients with heart failure and left bundle branch block. To test a new synchrony index derived from mitral annular velocity by color tissue Doppler, 19 subjects were studied: 9 patients with heart failure and left bundle branch block at baseline and at 1, 3 and 6 months after CRT and 10 normal controls. The synchrony index in patients with heart failure was less than that in controls at baseline (r = 0.

Second-generation tissue Doppler with angle-corrected color-coded wall displacement for quantitative assessment of regional left ventricular function.

To test the hypothesis that a new tissue Doppler (TD) approach using angle-correction and transformation of velocity data to color-coded displacement data may objectively quantify regional left ventricular function, in vitro experiments were first performed with an oscillating echo target precisely controlled by a microstepping motor. Displacement varied from 1 to 15 mm (60 to 130 cycles/min) at angles of 0 degrees and 45 degrees to the echo transducer. Custom software transformed TD data to displacement data.