Left Ventricular Assist Devices Dysfunction Research Articles

The Use of the Multisensor HeartLogic Algorithm for Heart Failure Remote Monitoring in Patients With Left Ventricular Assist Devices.

The Use of the Multisensor HeartLogic Algorithm for Heart Failure Remote Monitoring in Patients With Left Ventricular Assist Devices.

Outflow graft obstruction after left ventricular assist device implantation: a retrospective, single-centre case series.

AimsOutflow graft obstruction is a poorly described complication following left ventricular assist device (LVAD) surgery. We sought to define the incidence of LVAD outflow graft obstruction and assess clinical outcomes with a percutaneous treatment strategy.Methods and resultsFrom January 2012 to October 2020, 322 patients with LVAD were managed at our institution. Patients with LVAD outflow graft obstruction were identified by cardiac computed tomography with angiography and invasive haemodynamic assessment and were subsequently treated with percutaneous intervention. Poisson regression was used to analyse time‐dependent differences in the incidence of LVAD outflow graft obstruction. Kaplan–Meier analysis was used to estimate survival. Twenty patients (6.2%) developed haemodynamically significant LVAD outflow graft obstruction at a rate of 0.03 events per patient‐year. Outflow graft obstruction presented a median of 33 (26–49) months after surgery. Patients presented with low estimated LVAD pump flow (95%), heart failure (90%), or both (85%), and 59% developed cardiogenic shock prior to intervention. The most common aetiology identified by cardiac computed tomography with angiography was external compression of the outflow graft (78%). On presentation, the median peak gradient in the outflow graft was 78 (64–100) mmHg. Outflow graft stenting was 100% successful with no in‐hospital mortality, and it reduced the peak outflow graft gradient to 10 (2–17) mmHg (P < 0.001). Outflow graft stenting was durable with two patients (10%) requiring a repeat procedure over a median follow‐up of 13 (7–20) months and did not impact survival.ConclusionsLeft ventricular assist device outflow graft obstruction is a relatively common and underappreciated cause of recurrent heart failure and LVAD dysfunction. Outflow graft stenting can be achieved with low morbidity and provides a long‐term solution to this complication.

Percutaneous Intervention for Left Ventricular Assist Device Outflow Obstruction

Left ventricular assist devices (LVADs) are used to support patients with advanced systolic heart failure (HF). These patients might develop LVAD dysfunction and consequent HF symptoms. Occasionally, outflow graft obstruction is responsible for LVAD dysfunction. Here, we describe percutaneous techniques to repair the outflow graft and avoid re-sternotomy.

ACLS and Chest Compressions in Patients with Durable LVADs

Introduction Durable left ventricular assist devices (LVADs) are increasingly used to improve longevity in patients with advanced heart failure; however, optimal management of end-of-life issues including cardiopulmonary arrest remains uncertain for this relatively new population. We aim to assess the safety and efficacy of Advanced Cardiovascular Life Support (ALCS) including chest compressions in patients with LVADs. Methods We performed a retrospective chart review of all LVAD patients that received ACLS and chest compressions for in-hospital cardiopulmonary arrest at a single academic medical center between 2011 and 2017. We evaluated post-arrest survival, LVAD parameters/function, imaging studies, and autopsy results to assess for (1) structural issues such as LVAD dislodgment, aortic dissection/rupture, or pericardial effusion, and (2) LVAD mechanical issues such as hardware or software failure. Results Durable LVADs were implanted in 191 patients during the study period, of which 18 patients (9%) suffered in-hospital cardiopulmonary arrest necessitating ACLS (median of 22.5 days, range from 1 to 1323 days from implant). Of the patients requiring ACLS 11 (61%) survived the arrest with 7 (39%) surviving to hospital discharge. Ten patients (56%) received manual external chest compressions, and 7 (39%) received defibrillator shocks. Of the patients who received chest compressions and/or defibrillator shocks, no significant changes to LVAD parameters/function was noted after the arrest. Five autopsies were completed, all of which reported the LVAD in its proper position without evidence structural or mechanical LVAD complications. Two of the surviving patients were taken emergently to the operating room for treatment of cardiac tamponade; during the procedure the LVAD anastomoses were inspected, and no bleeding was noted in either case. Two echocardiograms were performed following chest compressions without evidence of LVAD dysfunction. There were no iatrogenic sequelae identified in any of the patients following ACLS. Conclusion While cardiopulmonary arrest in patients with LVADs is associated with high mortality, ACLS with chest compressions appears to be safe. Larger studies are warranted to identify patterns of post ALCS complications and define potential population-specific management.

Non-cardiac surgery in patients with continuous-flow left ventricular assist devices: a single institutional experience

With improvements in life expectancy for patients with continuous-flow left ventricular assist devices (LVADs), non-cardiac surgeons will increasingly encounter surgical problems in this population. 209 patients underwent LVAD placement between...

Left Ventricular Assist Device Inflow Angle and Pump Positional Change Over Time Adverse Impact on Left Ventricular Assist Device Function

This study investigates the impact of left ventricular assist device (LVAD) inflow cannula angulation, pump positional change over time, and the incidence of thrombotic pump dysfunction in a large cohort of HeartMate II (HM2) patients. Patients (n= 326) who received primary HM2 LVAD between January 2008 and December 2013 at a single institution were retrospectively reviewed. Patientswho underwent pump exchange (PE) for pump dysfunction, patients who had pump dysfunction (PD) but did not require pump exchange, and patients with normal LVAD pump dysfunction (NL) were compared. Pump positional change and angle of the inflow cannula with respect to the angle between inflow cannula and the LVAD body (IL angle) were measured from routine chest radiograph at postoperation, before discharge, and follow-up. Pump positional change was assessed based on pump positional differences between discharge and follow-up. Patients were also grouped by IL acute angulation (less than 65 degrees) and pump positional change. There were 21, 15, and 290 patients in the PE group, PD group, and NL group, respectively. There were significant differences in IL angle between PE and NL at all timepoints: postoperation (PD 63.6 ± 12.5, NL 70.6±12.3; p= 0.018), before discharge (PD 64.4 ± 12.8, NL 69.5 ± 10.5; p= 0.039), and follow-up (PD 62.6 ± 14.2, NL 67.9 ± 11.2; p= 0.002). However, the IL angle was insignificant between PE and PD groups and between PD and NL groups. Sixty-seven percent of the PE group had pump positional change as opposed to 36% of the NL group (p= 0.019). Eighty-four of 101 patients with pump positional change and 75 of 91 patients with acute angulation at postoperation did not have pump dysfunction. Pump positional change may contribute to LVAD dysfunction or failure, but it does not entirely account for observed pump dysfunction or failure.

RECURRENT LVAD DYSFUNCTION REQUIRING PUMP EXCHANGE TWICE IN A 24-HOUR SPAN

The use of left ventricular assist devices (LVADs) in end-stage heart failure is increasing. LVAD dysfunction can occur due to primary and secondary causes. An example of a primary cause is driveline failure leading to pump stoppage. Secondary causes of LVAD dysfunction include device thrombosis.

The use of eptifibatide for suspected pump thrombus or thrombosis in patients with left ventricular assist devices

Pump thrombosis in patients with left ventricular assist devices (LVADs) continues to present treatment challenges. Anti-coagulation strategies used to treat this complication are empiric and without firm data for guidance. The addition of a platelet glycoprotein IIb/IIIa inhibitor to intravenous anti-coagulation has been suggested by several case series and recent guidelines. The aim of this study was to evaluate our use of eptifibatide for the treatment of suspected pump thrombus/thrombosis. This retrospective, single-center cohort study was performed at Barnes-Jewish Hospital. The medical informatics system was queried to identify all LVAD patients who received eptifibatide for suspected pump thrombus/thrombosis from January 1, 2011, through April 30, 2013. A total of 17 patients (16 HeartMate II [Thoratec, Pleasanton, CA], 1 HeartWare [HeartWare International Inc, Framingham, MA]) with 22 separate administration attempts received eptifibatide (dose range, 0.1-2 μg/kg/min) for suspected pump thrombus/thrombosis presenting as one or more of the following findings: elevated lactate dehydrogenase, decreased haptoglobin, elevated plasma free hemoglobin, LVAD dysfunction, or new, persistently high LVAD power. The mean time from device implantation to eptifibatide therapy was 47.34 days (range, 3.88-397.67 days). Of the 22 attempts, 5 (22.7%) resulted in resolution of 1 or more patient-specific indicators of LVAD thrombus/thrombosis. Three patients (17.6%) had resolution of an indicator while also remaining free from continued hemolysis, death, pump exchange, or emergent heart transplant. Bleeding events were common, with 11 patients (64.7%) experiencing bleeding during the infusion. Seven patients (41.2%) died, with intraparenchymal hemorrhage as the cause of death in 2 patients. Pump exchange was performed in 3 patients. Our limited experience indicates the risk of using eptifibatide outweighs the proposed benefit of salvaging the existing LVAD in the setting of suspected pump thrombus/thrombosis at our institution.

Role of Echocardiography in Patients With Intravascular Hemolysis Due to Suspected Continuous-Flow LVAD Thrombosis

This study sought to characterize the echocardiographic findings of patients presenting with intravascular hemolysis (IVH) due to suspected continuous-flow left ventricular assist device (LVAD) pump thrombosis. LVAD patients who develop pump thrombosis often present with IVH. Echocardiography may be able to detect device dysfunction in this setting. Continuous-flow LVAD patients presenting with IVH due to suspected pump thrombosis were identified. Patients underwent echocardiography with cannula Doppler flow velocity interrogation. Findings were compared with baseline and follow-up studies, and with 49 stable LVAD control patients. Of 145 patients, 14 (10%) had IVH due to suspected pump thrombosis. The mean age was 55 ± 15 years, 93% were men, and 50% received LVAD as destination therapy. Mean duration between implantation and IVH was 231 ± 218 days. Eleven (79%) patients presented with hemoglobinuria, 9 (64%) with jaundice, and 5 (36%) with acute heart failure. Reduced cannula diastolic flow velocity and increased systolic/diastolic (S/D) flow velocity ratio were the only echocardiographic parameters significantly different from controls (outflow cannula 0.3 ± 0.2 m/s vs. 0.8 ± 0.3 m/s, p = 0.03, and 5.9 ± 2.8 vs. 1.7 ± 0.7, p < 0.01, respectively), and were worse for IVH patients with acute heart failure compared with those without (outflow cannula 0.2 ± 0.1 m/s vs. 0.5 ± 0.2 m/s, p = 0.04, and 7.2 ± 3.3 vs. 5.3 ± 2.0, p = 0.02, respectively). Outflow cannula diastolic flow velocity and S/D flow velocity ratio changed significantly from baseline (p = 0.01 and p < 0.01, respectively) in IVH patients, whereas systolic flow velocity did not change (p = 0.59). Odds ratios for outflow cannula diastolic flow velocity and S/D flow velocity ratio for predicting IVH were 0.60 (95% confidence interval [CI]: 0.51 to 0.73), p = 0.02, and 2.45 (95% CI: 2.37 to 2.52) p < 0.01, respectively. Corresponding inflow cannula values were similarly significant. Pump thrombosis was confirmed in 7 (50%) patients after LVAD retrieval. Reduced cannula diastolic flow velocity and increased S/D flow velocity ratio identified continuous-flow LVAD dysfunction in patients with IVH due to suspected pump thrombosis better than other echocardiographic parameters.

Is Intermittent Hemodialysis Safe in Patients with a Continuous Flow Left Ventricular Assist Device?

Purpose Dialysis centers are wary of performing intermittent hemodialysis (HD) on patients with continuous flow (CF) left ventricular assist devices (LVAD) because of the potential for volume flux related complications and Doppler probe dependent blood pressure monitoring. We report the conduct of HD in patients with LVAD (Heart Mate II), identify events requiring modification of or termination of HD and their management. Methods and Materials We abstracted clinical data from dialysis session on all patients who underwent intermittent HD following placement of LVAD at our institution. Results From June 2009 to October 2012, 139 patients received LVAD at our institution, 10 (7%) required intermittent HD post-operatively. Mean age was 53±14yrs, 90% were male. A total of 281 HD sessions were administered amounting to 1,025 hours of HD. Mean systolic blood pressure monitored with Doppler was 97±18mmHg. Dialysis durations averaged 218±18 mins, mean blood flow rate was 334±38 cc/min and 2.6±1.1 L was ultrafiltrated during each HD session. Only 15 (5.3%) HD sessions were interrupted or terminated in 6 patients, due to symptomatic hypotension 6, asymptomatic hypotension 3, ventricular tachycardia terminated with AICD 1, HD machine malfunction 2, low phosphorus 2 and abdominal cramps 1. Volume expansion was necessary on 3 occasions in 2 patients both of whom were transferred to intensive care unit for sepsis. Low flow LVAD alarms were registered during 2 of the symptomatic hypotension episodes. No serious adverse effect i.e. MI, LVAD thrombosis or stroke was observed. Conclusions Intermittent HD with standard blood flow and ultrafiltration rates were well tolerate in patients with CF LVAD. Hypotension, LVAD dysfunction or serious adverse effects requiring termination of HD were infrequent. Reason for terminating HD Frequency (%) Symptomatic Hypotension 6 (2) Aymptomatic Hypotension 3 (1) HD machine malfunction 2 (0.7) Low phosphorus 2 (0.7) Abdominal cramps 1 (0.36) Ventricular tachycardia 1 (0.36) Total 15 (5.3)

The Role of Echocardiography in Patients with Intravascular Hemolysis Due to Suspected Continuous-Flow Left Ventricular Assist Device Thrombus

Purpose Continuous-flow left ventricular assist devices (LVAD) provide hemodynamic support for patients with advanced heart failure (HF). Some patients develop intravascular hemolysis (IVH) due to pump thrombus, although the utility of echocardiography for detecting compromised LVAD circulatory support in this setting is unknown. Methods and Materials Patients with HeartMate II LVADs presenting with IVH due to suspected pump thrombus were identified. Patients underwent echocardiography with Doppler-flow velocity (DFV) interrogation of inflow and outflow cannulae at baseline and presentation. IVH was defined as an acute rise in serum lactate dehydrogenase more than two fold from baseline with supportive clinical symptoms. Results Of 162 patients, 14 (8%) had IVH due to suspected pump thrombus. The mean age was 55±14 years, and duration between implant and presentation was 231±218 days. Eleven patients presented with hemoglobinuria, 9 with jaundice and 7 with acute HF. There was no change in mean inflow or outflow cannula systolic DFV from baseline to presentation (0.9±0.3 to 0.8±0.3 m/sec, p=0.45 and 1.3±0.3 to 1.3±0.4 m/sec, p=0.38), while diastolic DFV declined significantly (0.5±0.3 to 0.2±0.2 m/sec, p Conclusions Reduced cannula diastolic DFV identified LVAD dysfunction in patients with IVH due to suspected pump thrombus more often than other echocardiographic markers of impaired pump function, and was lower in patients presenting with acute HF.

Transthoracic Echocardiographic Assessment of Continuous-Flow Left Ventricular Assist Devices

An increasing number of patients are implanted with continuous-flow left ventricular assist devices (LVAD) for the treatment of severe congestive heart failure. In parallel with this growing experience has been an increase in knowledge of how these devices alter cardiac physiology and the important implications this has for cardiac function. Echocardiography offers the ability to provide serial noninvasive evaluation before and after LVAD implantation to document these changes, guide management decisions, and identify LVAD dysfunction. The authors detail a comprehensive assessment of LVAD function by transthoracic echocardiography.

Use of Gated Cardiac Computed Tomography Angiography in the Assessment of Left Ventricular Assist Device Dysfunction

The purpose of this study is to describe the utility and limitations of gated contrast-enhanced cardiac computed tomography angiography in assessing left ventricular assist device function. Computed tomography angiography (CTA) was used in 14 patients with left ventricular assist devices (LVADs) who had persistent heart failure symptoms, hemodynamic instability, or potential problems with LVAD flows. Retrospectively gated contrast-enhanced CTA was performed on 64-detector scanner, and the CTA images were postprocessed in multiple curved projections on TeraRecon workstation. This study describes the use of CTA to identify LVAD-related issues that altered clinical management and explores the role of CTA and other techniques in evaluating LVAD function. Six of 14 LVAD patients who demonstrated no abnormality on CTA remained stable with medical management. In the remaining eight patients, CTA was abnormal, including abnormalities specifically related to the LVAD cannula. As a result of findings detected by CTA, six patients underwent surgical intervention, including device exchange and heart transplant. Computed tomography angiography is a noninvasive method that enhances diagnostic evaluation of patients with suspected LVAD dysfunction and can lead to changes in patient management.

The physiologic basis for the management of ventricular assist devices

Mechanical ventricular assist devices are now approved as destination therapy for terminal heart failure. It is the purpose of this review to discuss the physiology of this technology that is considered in outpatient care. The currently available pulsatile devices are solely dependent of preload volume and, when placed in the automatic mode, can maintain physiologic cardiac outputs with exercise. However, because of their dependence on preload volume, there are unique physiologic consequences; device bradycardia represents volume depletion, device tachycardia reflects volume overload. The differential diagnosis of left ventricular assist device dysfunction includes native right ventricular failure, native left ventricular recovery, or other technical considerations. The management of biventricular mechanical support as well as arrhythmia management and the role of echocardiographic assessment in this unique patient population will be discussed. Expertise in outpatient management of such devices is now a requisite for subspecialists in heart failure, In the future, technical innovations may simplify management for professionals, patients, and their families.

Assessment of Recurrent Heart Failure Associated with Left Ventricular Assist Device Dysfunction

Patients with advanced heart failure may require long-term support with an intracorporeal left ventricular assist device (LVAD) before cardiac transplant, while awaiting myocardial recovery, or during destination therapy. Compared with the diagnosis of native heart dysfunction, there is less experience with the assessment of recurrent heart failure after LVAD placement. Ten patients (9 men, 1 woman; age, 58 +/- 11 years) were studied after LVAD placement. Six patients were studied because of recurrent heart failure; the remaining 4 had other indications for study and are reported here as controls. Cardiac catheterization, including LVAD and cannulae catheterization, and angiography were performed. Inflow cannula valve regurgitation by LVAD angiography was found in 3 cases. Patients with regurgitation had a mean increased resting LVAD rate of 105 beats/min (range, 90-120); LVAD output exceeded forward cardiac output (LVAD - thermodilution cardiac output = +3.7 liters/min [0.6-6.4]). Inflow cannula obstruction identified with a filling phase pressure gradient between the left ventricle and the LVAD was found in 3 additional patients. Patients with obstruction had decreased resting LVAD rates (50 beats/min, all patients); LVAD output was less than the forward cardiac output (LVAD - thermodilution cardiac output = -2.3 liters/min [-0.8 to -3.5]). Compared with those with inflow valve regurgitation, patients with cannula obstruction had higher pulmonary capillary wedge pressures; phasic left ventricular pressure variation was reduced. Patients with cannula dysfunction underwent surgical intervention, and 4 of 6 were long-term survivors. When heart failure recurs after LVAD placement, abnormalities of the inflow cannula are common. Cardiac catheterization can confirm the diagnosis before surgical intervention. Hemodynamic coupling between the left ventricle and the LVAD is increased with inflow valve regurgitation and reduced with cannula obstruction.

Left Ventricular Assist Device Malfunction: An Approach to Diagnosis by Echocardiography

A protocol using transthoracic echocardiography was designed to diagnose the common malfunctions of patients on chronic support with a left ventricular assist device (LVAD). Mechanical circulatory support, primarily with a LVAD, is increasingly used for treatment of advanced heart failure as a bridge to transplant and for long-term treatment of heart failure. The LVAD dysfunction is a recognized complication. To date, no studies have defined the role of transthoracic echocardiography in evaluating long-term mechanical complications of chronic LVAD support. Transthoracic echocardiography was used in a protocol designed to detect the common types of mechanical malfunction. Patients were followed up with serial echocardiograms, and clinical validations were made with findings from a catheter-based protocol and inspection at the time of cardiac transplant or corrective surgery. Thirty-two patients with 44 LVADs were followed up during a four-year period using this protocol that correctly identified 11 patients with inflow valve regurgitation, 2 with intermittent inflow conduit obstruction, 1 with severe kinking of the outflow graft, and 9 with new insufficiency of the native aortic valve. As LVAD use for end-stage heart failure becomes widespread, and durations of support are extended, dysfunction will be increasingly prevalent. Transthoracic echocardiography provides a practical method to accurately identify the causes of mechanical dysfunction with patients on chronic LVAD support.

Left ventricular assist device malfunction: a systematic approach to diagnosis

ObjectivesA protocol was designed to diagnose the common malfunctions of a left ventricular assist device (LVAD). BackgroundMechanical circulatory support, primarily with an LVAD, is increasingly used for treatment of advanced heart failure (HF). Left ventricular assist device dysfunction is a recognized complication; but heretofore, a systematic method to accurately diagnose LVAD dysfunction has not been thoroughly described. MethodsWe developed a catheter-based protocol designed to characterize a normally functioning LVAD and diagnose multiple types of dysfunction. A total of 15 studies of 10 patients supported with an LVAD were reviewed. All patients had been evaluated due to concerns regarding LVAD dysfunction. ResultsOf 15 examinations performed, 11 documented severe LVAD inflow valve regurgitation. One of these cases proved to have coexistent severe mitral valve regurgitation. One case was diagnosed with distortion of the LVAD outflow graft. One case of suspected embolization from the pumping chamber excluded the outflow graft as the source of emboli. One study had aortic insufficiency. ConclusionsAs LVAD use for treatment of end-stage HF becomes widespread and durations of support are extended, dysfunction will be increasingly prevalent. This catheter-based protocol provided a practical method to diagnose multiple causes of LVAD dysfunction.

Simulation of systolic and diastolic left ventricular dysfunction in a mock circulation: the effect of arterial compliance

Arterial compliance (AC) is expected to play a major role on cardiac efficacy by acute or long-term mechanisms. The aim of this study was to investigate the purely mechanical effect of AC on left ventricular (LV) performance, for different conditions of LV dysfunction (systolic versus diastolic). A hydraulic, Windkessel model of systemic circulation was used. LV function and aortic flow were simulated using a left ventricular assist device (LVAD). Two cases of LV dysfunction were simulated: Case A, systolic and Case B, diastolic dysfunction. In Case A, AC increased from 1.14 to 2.85 ml mm Hg m 1 leading to an increase in LVAD stroke volume up to 6%, while no significant effect was observed in Case B. LVAD systolic work was decreased by 4% in systolic and by 11% in diastolic LVAD dysfunction. The purely mechanical effect of AC changes on LVAD function was different between systolic and diastolic dysfunction. It might be expected that even an acute reduction in arterial stiffness could enhance LV performance by different means in systolic compared to diastolic dysfunction.