Echocardiographic assessment of flow across continuous-flow ventricular assist devices at low speeds

George, Robert S.; Sabharwal, Nikant; Webb, Carole; Yacoub, Magdi H.; Bowles, Christopher; Hedger, M.; Khaghani, Asghar; Birks, Emma J.

doi:10.1016/j.healun.2010.05.032

Cited by 50 publications

(38 citation statements)

References 18 publications

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“…This can be prevented by reducing the continuous-flow LVAD speed to a rate at which there is no forward flow or backflow, thus allowing an accurate assessment. On the basis of a detailed HMII echocardiographic investigation, which has been the subject of a separate study, 18 we have found that this occurs when the HMII speed is reduced to 6000 rpm. Therefore, testing was performed at 6000 rpm in this study.…”

Section: Discussionmentioning

confidence: 89%

Reversal of Severe Heart Failure With a Continuous-Flow Left Ventricular Assist Device and Pharmacological Therapy

et al. 2011

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Background-We have previously shown that a specific combination of drug therapy and left ventricular assist device unloading results in significant myocardial recovery, sufficient to allow pump removal, in two thirds of patients with dilated cardiomyopathy receiving a Heartmate I pulsatile device. However, this protocol has not been used with nonpulsatile devices. Methods and Results-We report the results of a prospective study of 20 patients who received a combination of angiotensin-converting enzymes, ␤-blockers, angiotensin II inhibitors, and aldosterone antagonists followed by the ␤ 2 -agonist clenbuterol and were regularly tested (echocardiograms, exercise tests, catheterizations) with the pump at low speed. Before left ventricular assist device insertion, patient age was 35.2Ϯ12.6 years (16 male patients), patients were on 2.0Ϯ0.9 inotropes, 7 (35%) had an intra-aortic balloon pump, 2 were hemofiltered, 2 were ventilated, 3 had a prior Levitronix device, and 1 had extracorporeal membrane oxygenation. Cardiac index was 1.39Ϯ0.43 L ⅐ min Ϫ1 ⅐ m Ϫ2 , pulmonary capillary wedge pressure was 31.5Ϯ5.7 mm Hg, and heart failure history was 3.4Ϯ3.5 years. One patient was lost to follow-up and died after 240 days of support. Of the remaining 19 patients, 12 (63.2%) were explanted after 286Ϯ97 days. Eight had symptomatic heart failure for Յ6 months and 4 for Ͼ6 months (48 to 132 months). Before explantation, at low flow for 15 minutes, ejection fraction was 70Ϯ7%, left ventricular end-diastolic diameter was 48.6Ϯ5.7 mm, left ventricular end-systolic diameter was 32.3Ϯ5.7 mm, mV O 2 was 21.6Ϯ4 mL ⅐ kg Ϫ1 ⅐ min Ϫ1 , pulmonary capillary wedge pressure was 5.9Ϯ4.6 mm Hg, and cardiac index was 3.6Ϯ0.6 L ⅐ min Ϫ1 ⅐ m Ϫ2 . Estimated survival without heart failure recurrence was 83.3% at 1 and 3 years. After a 430.7Ϯ337.1-day follow-up, surviving explants had an ejection fraction of 58.1Ϯ13.8%, left ventricular end-diastolic diameter of 59.0Ϯ9.3 mm, left ventricular end-systolic diameter of 42.0Ϯ10.7 mm, and mV O 2 of 22.6Ϯ5.3 mL ⅐ kg Ϫ1 ⅐ min Ϫ1 . Conclusions-Reversal of end-stage heart failure secondary to nonischemic cardiomyopathy can be achieved in a substantial proportion of patients with nonpulsatile flow through the use of a combination of mechanical and pharmacological therapy. (Circulation. 2011;123:381-390.)

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Section: Discussionmentioning

confidence: 89%

Reversal of Severe Heart Failure With a Continuous-Flow Left Ventricular Assist Device and Pharmacological Therapy

et al. 2011

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“…Test measurements were obtained with the LVAD at full speed initially, followed by reduction of the pump speed to 6000 rpm (at which speed there is no net forward or reverse flow). 99 Twelve of the 20 (60%) patients showed sufficient recovery to undergo explantation and duration of LVAD support was 286±97 days. Actuarial survival after explantation was 83.3% at 1, 2, and 3 years.…”

Section: Clinical Relevancementioning

confidence: 97%

Molecular Changes After Left Ventricular Assist Device Support for Heart Failure

Birks

2013

Circulation Research

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Abstract-Heart failure is associated with remodeling that consists of adverse cellular, structural, and functional changes in the myocardium. Until recently, this was thought to be unidirectional, progressive, and irreversible. However, irreversibility has been shown to be incorrect because complete or partial reversal can occur that can be marked after myocardial unloading with a left ventricular assist device (LVAD). Patients with chronic advanced heart failure can show near-normalization of nearly all structural abnormalities of the myocardium or reverse remodeling after LVAD support. However, reverse remodeling does not always equate with clinical recovery. The molecular changes occurring after LVAD support are reviewed, both those demonstrated with LVAD unloading alone in patients bridged to transplantation and those occurring in the myocardium of patients who have recovered enough myocardial function to have the device removed. Reverse remodeling may be attributable to a reversal of the pathological mechanisms that occur in remodeling or the generation of new pathways. A reduction in cell size occurs after LVAD unloading, which does not necessarily correlate with improved cardiac function. However, some of the changes in both the cardiac myocyte and the matrix after LVAD support are specific to myocardial recovery. In the myocyte, increases in the cytoskeletal proteins and improvements in the Ca 2+ handling pathway seem to be specifically associated with myocardial recovery. Changes in the matrix are complex, but excessive scarring appears to limit the ability for recovery, and the degree of fibrosis in the myocardium at the time of implantation may predict the ability to recover. (Circ Res. 2013;113:777-791.)

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“…To test the patient's native LV functional reserve, an exercise test (such as a 6-minute walking test or other cardiopulmonary test) should be considered at one or more time intervals at the net neutral low pump speed. 84,85 At the conclusion of the exercise test, LV function parameters, including the LVEF, should again be assessed. Early termination of the test with restoration of the baseline LVAD speed is warranted if the patient becomes symptomatic.…”

Section: Lvad Recovery Echo Exammentioning

confidence: 99%

Echocardiography in the Management of Patients with Left Ventricular Assist Devices: Recommendations from the American Society of Echocardiography

Stainback¹,

Estep

Agler

et al. 2015

Journal of the American Society of Echocardiography

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139

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Echocardiographic assessment of flow across continuous-flow ventricular assist devices at low speeds

Cited by 50 publications

References 18 publications

Reversal of Severe Heart Failure With a Continuous-Flow Left Ventricular Assist Device and Pharmacological Therapy

Reversal of Severe Heart Failure With a Continuous-Flow Left Ventricular Assist Device and Pharmacological Therapy

Molecular Changes After Left Ventricular Assist Device Support for Heart Failure

Echocardiography in the Management of Patients with Left Ventricular Assist Devices: Recommendations from the American Society of Echocardiography

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