Publications by authors named "Courtney Gemmato"

Introduction: Implementation of continuous flow (CF) technology in modern ventricular assist devices (VAD) has afforded a wealth of engineering and design advantages in the development of a total artificial heart (TAH). However, clinical application of CF has created a unique physiologic state, the consequences of which remain largely unknown. We sought to evaluate clinical and biochemical markers of end-organ function in calves supported with biventricular CF VADs for more than 30 days.

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The widespread use of continuous-flow left ventricular assist devices for mechanical circulatory support has shown that long-term hemodynamic support is possible, even when a clinical "pulse" cannot be detected. We present the incidental discovery of ventricular fibrillation in 6 alert, hemodynamically stable patients supported only by a continuous-flow device (HeartMate II, n=5; Jarvik 2000, n=1). Ventricular fibrillation was found in 3 patients during routine outpatient follow-up visits and in 3 awaiting discharge from the hospital after device placement.

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Background: We hypothesized that not all subtypes of alpha- and beta-adrenoreceptors undergo similar upregulation and redistribution in human myocardium after mechanical unloading with an assist device.

Methods: We obtained core biopsy samples of the left ventricle in 19 patients before and after removal of a Jarvik or Thoratec left ventricular assist device (LVAD) to study the effect of mechanical unloading on the distribution of alpha- and beta-adrenoreceptors. Fresh, embedded tissue sections were incubated with receptor blockers and antibodies before the fluorescent labeling of receptors.

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Background: Implantation of a HeartMate II or a Jarvik 2000 FlowMaker left ventricular assist system (LVAS) usually involves a mid-line sternotomy and the use of cardiopulmonary bypass (CPB). In patients with numerous co-morbid conditions, however, surgical trauma may be minimized by implanting the LVAS via a minimally invasive approach, preferably without CPB.

Methods: In 6 patients with end-stage heart failure and other serious co-morbidities, we implanted a HeartMate II (n = 3) or a Jarvik 2000 FlowMaker (n = 3) LVAS via a right mini-thoracotomy and a left sub-costal incision.

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In this study, long-term (90-day) hemocompatibility and end-organ effects of a centrifugal left ventricular assist device (the Heartware HVAD) were evaluated in 6 healthy sheep. The device was implanted into the left ventricular apex on beating hearts. The outflow graft of each device was anastomosed to the descending aorta.

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The redesigned HeartMate II, an axial-flow left ventricular assist device, is simpler, smaller, and easier to operate than are pulsatile pumps. These design characteristics should make the HeartMate II more reliable and durable and broaden the eligible population base. We implanted the HeartMate II in 43 patients (average age, 42 yr).

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Long-term left ventricular assist device (LVAD) implantation is associated with an inherent risk of transient ischemic attacks (TIAs). When TIAs occur in patients who have undergone placement of a HeartMate XVE LVAD, the pump must be assumed to be the likely source of the TIA. The HeartMate XVE is unique in that it has a pumping surface of flocked Biomer and a pump housing and inlet cannula coated with sintered titanium.

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Air embolism is a rare and usually fatal complication of major cardiac surgery. We present a case in which a 45-year-old man supported by a HeartMate(R) XVE left ventricular assist device required a pump exchange due to failure of the device motor. During pump dissection, a massive amount of air entered the systemic circulation.

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In adult patients, mechanical circulatory support (MCS) devices are part of the standard of care for heart failure. There are several options available that clinicians may use to provide support for their patients and thus the choice of devices can be tailored to their individual needs. Unfortunately, this is not the case for pediatric patients with heart failure, where the options for MCS modalities are far more limited because of size constraints and regulatory hurdles.

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The TandemHeart percutaneous ventricular assist device can be used to support patients in cardiogenic shock (until cardiac recovery occurs or as a bridge to definitive therapy) or as a temporary application during high-risk coronary interventions. The TandemHeart is a left atrial-to-femoral artery bypass system comprising a transseptal cannula, arterial cannulae, and a centrifugal blood pump. The pump can deliver flow rates up to 4.

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OBJECTIVES: We describe our experience in using the TandemHeart percutaneous ventricular assist device (pVAD) during high-risk percutaneous coronary intervention (PCI). BACKGROUND: Coronary artery bypass grafting (CABG) is the preferred treatment for disease in an unprotected left main coronary artery or left main equivalent. However, severe comorbidities may preclude surgery in some patients.

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Objectives: We describe our experience in using the TandemHeart percutaneous ventricular assist device (pVAD) during high-risk percutaneous coronary intervention (PCI).

Background: Coronary artery bypass grafting (CABG) is the preferred treatment for disease in an unprotected left main coronary artery or left main equivalent. However, severe comorbidities may preclude surgery in some patients.

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Since the 1960s, the Texas Heart Institute has been intimately involved in the development of mechanical circulatory support devices (for example, ventricular assist devices, aortic counterpulsation pumps, and total artificial hearts) for both short- and long-term use. Here, we review the varied clinical experience with these technologies at the Texas Heart Institute over the last 35 years.

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Coronary artery bypass grafting prolongs survival in patients with left main coronary artery stenosis. However, this benefit is denied to patients who refuse the procedure or who are poor surgical candidates due to comorbid conditions. We describe a novel technique for the percutaneous revascularization of stenosis in an unprotected left main coronary artery in high-risk patients.

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