Igor D Gregoric

Texas Heart Institute, Houston, TX, USA

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Publications (128)280.48 Total impact

  • Article: Transthoracic echocardiography of the HeartWare left ventricular assist device.
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    ABSTRACT: The unique findings on transthoracic echocardiography of the HeartWare left ventricular assist device (LVAD) have not been previously described. HeartWare LVADs were implanted in 19 patients from May 2009 through December 2010; 152 comprehensive transthoracic echocardiograms (TTEs) performed postoperatively on these patients were retrospectively analyzed for device component visualization, inlet cannula/outflow conduit flow velocities, and imaging artifacts. The inlet cannula was adequately visualized in 66% of studies, incompletely visualized in 14%, and not visualized in 20%. Spectral Doppler interrogation of inlet cannula flow velocity was always uninterpretable due to artifact. Standard parasternal long-axis and apical views always included the inlet cannula in the imaging sector, resulting in a prominent "waterfall" color Doppler artifact obscuring the mitral valve. Inclusion of the inlet cannula in the imaging sector also precluded spectral Doppler interrogation of the mitral valve owing to artifact. The outflow conduit was partially visualized and interrogated by spectral Doppler in 68% of studies, and the average measured peak flow velocity was 1.4 m/s (range 1.0-1.9 m/s). The HeartWare LVAD inlet cannula and outflow conduit are both readily visualized by TTE in a majority of patients. However, significant color and spectral Doppler artifacts occur when the inlet cannula is visualized in the imaging sector, necessitating routine off-axis Doppler interrogation of the mitral valve.
    Journal of cardiac failure 09/2012; 18(9):745-8. · 3.25 Impact Factor
  • Article: Percutaneous Stenting to Treat Pulmonary Vein Stenosis after Single-Lung Transplantation.
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    ABSTRACT: Pulmonary vein stenosis after lung transplantation is rare. Untreated, it can cause transplant failure and death. We describe the case of a 56-year-old man in whom pulmonary vein stenosis developed after singlelung transplantation. He was successfully treated with angioplasty and stent implantation guided by intravascular ultrasonography. To our knowledge, this is the first report of using this method to evaluate the pulmonary vein after lung transplantation, to confirm the diagnosis of pulmonary vein stenosis, and to guide the sizing and positioning of a stent. In lung-transplant recipients, percutaneous stent implantation may preclude reoperation and salvage the transplanted lung when used as treatment for pulmonary vein stenosis.
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2012; 39(4):560-564. · 0.65 Impact Factor
  • Article: Percutaneous closure of a left ventricular pseudoaneurysm in a high-risk surgical candidate.
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    ABSTRACT: Few cases of percutaneous device closure of a left ventricular pseudoaneurysm have been reported. We describe the case of a 67-year-old man with a history of coronary artery disease who presented with shortness of breath and chest pain. Computed tomographic angiography showed a left ventricular pseudoaneurysm that was filling from a small leak in the anterolateral aspect of the ventricle. The patient had undergone 3 previous sternotomies and was a high-risk candidate for surgical treatment of the pseudoaneurysm. Despite technical challenges, we closed the pseudoaneurysm percutaneously with use of a 6-mm AMPLATZER muscular ventricular septal defect occluder. The patient was released from the hospital the next day and was asymptomatic a year later.To our knowledge, this is the first report of the percutaneous closure of a left ventricular pseudoaneurysm via the femoral vein. We show that this manner of closure can be feasible in patients who have undergone multiple sternotomies and who are at high surgical risk.
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2012; 39(5):680-2. · 0.65 Impact Factor
  • Article: Closure of post-myocardial infarction ventricular septal defect with use of intracardiac echocardiographic imaging and percutaneous left ventricular assistance.
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    ABSTRACT: WEBSITE FEATURE.
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2012; 39(3):454-6. · 0.65 Impact Factor
  • Article: Infected right atrial thrombus after explantation of a left ventricular assist device.
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    ABSTRACT: Finding the source of a fungal infection and selecting the most appropriate treatment for candidemia is often challenging for physicians, especially when the patient has a complex medical history. We describe the case of a 48-year-old woman who had persistent candidemia after undergoing explantation of a left ventricular assist device. The source of the infection was found to be a right atrial thrombus. The mass was removed, and the patient underwent aggressive treatment with micafungin. Removal of the right atrial mass, followed by potent antifungal treatment, resulted in a successful recovery.
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2012; 39(3):390-2. · 0.65 Impact Factor
  • Article: Long-term results of aortic banding for complex infrarenal neck anatomy and type I endoleak after endovascular abdominal aortic aneurysm repair.
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    ABSTRACT: For many patients with abdominal aortic aneurysm, unsuitable anatomy of the infrarenal aortic neck precludes endovascular aortic aneurysm repair or causes type I endoleak after the procedure. In an attempt to overcome these challenges, we retrospectively examined the usefulness of aortic banding as an adjunctive procedure to endovascular repair in 8 patients who had an abdominal aortic aneurysm with a complex infrarenal aortic neck. The procedures were performed with the patients under general anesthesia and involved making an 8-cm upper-midline laparotomy incision to expose the aneurysmal aorta. Three patients underwent aortic banding before endovascular repair; the other 5 underwent banding after the repair because of persistent type I endoleak. After banding, the abdominal aortic aneurysm was successfully excluded in all 8 patients. Long-term follow-up (mean, 38 ± 20 mo) revealed no type I endoleak and no procedure-related complications. In patients who have an abdominal aortic aneurysm with complex infrarenal neck anatomy or a refractory type I endoleak, performing aortic banding as an adjunctive procedure to endovascular aortic repair appears to be a safe strategy with good long-term results.
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2012; 39(6):799-805. · 0.65 Impact Factor
  • Article: Ventricular assist device outflow-graft site: effect on myocardial blood flow.
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    ABSTRACT: Recent advances in left ventricular assist device (LVAD) technology have resulted in small, durable, energy-efficient, continuous-flow blood pumps that can support patients with end-stage heart failure. However, the effects of reduced or nonpulsatile flow on end-organ function are unclear. We performed a pilot study in calves with a continuous-flow LVAD to assess the effects of the pump's outflow-graft location (ascending versus descending aorta) on myocardial blood flow. In 8 healthy calves, we implanted the Jarvik 2000 LVAD in the left ventricular apex without the use of cardiopulmonary bypass. We anastomosed the outflow graft to either the ascending aorta (group 1; n = 4) or the descending aorta (group 2; n = 4). Hemodynamic parameters, myocardial oxygen consumption, and regional myocardial blood flow (analyzed with colored microspheres) were assessed at baseline (pump off) and during pump operation at 8000, 10,000, and 12,000 rpm. No intergroup differences were found in the aortic pressure, heart rate, central venous pressure, pump-flow to total-cardiac-flow ratio, or blood flow in the left anterior descending and right posterior descending coronary arteries at increasing pump speeds. Neither myocardial oxygen consumption nor myocardial tissue perfusion differed significantly between the two groups. Regardless of the outflow-graft location (ascending versus descending aorta), the continuous-flow LVAD unloaded the left ventricle and did not adversely affect myocardial perfusion in either the right or left ventricle. Owing to the small number of animals studied, however, the most we can conclude is that neither outflow-graft location appeared to be inferior to the other.
    Journal of Surgical Research 11/2011; 171(1):71-5. · 2.25 Impact Factor
  • Article: Timely use of a CentriMag heart assist device improves survival in postcardiotomy cardiogenic shock.
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    ABSTRACT: Postcardiotomy cardiogenic shock (PCS) is often fatal despite inotropic and circulatory support. We compared our experience with the CentriMag left ventricular assist device (LVAD) for patients with PCS at two time periods: in the operating room (OR) after unsuccessful weaning from cardiopulmonary bypass (CPB) and after transfer to the intensive care unit (ICU). We reviewed 22 patients' records (13 men, nine women; age, 65 ± 12 years) who underwent open heart surgery (January 2004 to September 2009) and required LVAD support for PCS despite maximal inotropic and intra-aortic balloon pump (IABP) support. In ten patients who could not be weaned from CPB despite high-dose inotropic therapy (≥ 3 agents) and IABP support, the CentriMag was implanted in the OR (immediate group). The other 12 patients were weaned from CPB with high-dose inotropic therapy and IABP but became increasingly unstable or had a cardiac arrest in the ICU, and the CentriMag was implanted for circulatory support (delayed group). Preoperatively, the average ejection fraction was 40% ± 12%, the creatinine level was 1.6 ± 0.6 mg/dL, and the European Systematic Coronary Risk Evaluation was 13.1 ± 4.6. The duration of CentriMag support was 5 ± 3 days. The immediate group had significantly better survival (7/10 vs. 2/12, p = 0.027), higher cardiac index (2.4 ± 0.3 L/min/m(2) vs. 1.7 ± 0.3 L/min/m(2), p = 0.001), and lower pulmonary capillary wedge pressure (20 ± 6 mmHg vs. 29 ± 8 mmHg, p = 0.024) than the ICU group. No perioperative complications related to device implantation occurred. In patients with PCS, timely placement of a CentriMag LVAD may increase the chance of eventual recovery. 
    Journal of Cardiac Surgery 09/2011; 26(5):548-52. · 0.87 Impact Factor
  • Article: Less invasive off-pump implantation of axial flow pumps in chronic ischemic heart failure: survival effects.
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    ABSTRACT: Off-pump implantation of left ventricular assist device (LVAD) axial or centrifugal flow pumps in patients with low ejection fraction (EF) is of major clinical relevance. In addition, all pre-clinical, long-term implantations performed so far have been carried out in healthy animals, but this does not reflect the eventual clinical setting. In this study we established a new technique using a miniaturized axial flow pump in sheep with chronically ischemic myocardium. Sheep (n = 15) underwent intracoronary sphere injection to create chronic ischemic heart failure. Reduced EF was assessed using transesophageal echocardiography. All animals underwent implantation of a new miniaturized axial flow pump via an extraperitoneal, subcostal surgical approach. Our technique allows easy exposure of the diaphragmatic surface of the heart and the descending aorta. Ten animals (range 65 to 78 kg) underwent off-pump implantation 30 (range 25 to 33) days after intracoronary sphere injection. All animals had significantly reduced EF (25 ± 4.8%) and were receiving high doses of inotropic agents to maintain cardiac function. Nine animals survived the surgical procedure. The average 12-hour blood loss was 435 ml. Cardiac index improved significantly in all animals. The procedure time was not extended by any adverse events (60 to 145 minutes). The extraperitoneal, subcostal surgical approach is less invasive than a median sternotomy and allows centrifugal or axial to be implanted quickly and without cardiopulmonary bypass (CPB). Avoiding CPB and an extensive mediastinal dissection can help to decrease significantly the number of complications in patients with end-stage organ failure.
    The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation 07/2011; 30(7):834-7. · 3.54 Impact Factor
  • Article: Arteriovenous malformation and gastrointestinal bleeding in patients with the HeartMate II left ventricular assist device.
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    ABSTRACT: In this study we investigated gastrointestinal (GI) bleeding and its relationship to arteriovenous malformations (AVMs) in patients with the continuous-flow HeartMate II (HMII) left ventricular assist device (LVAD). The records of 172 patients who received HMII support between November 2003 and June 2010 were reviewed. Patients were considered to have GI bleeding if they had 1 or more of the following symptoms: guaiac-positive stool; hematemesis; melena; active bleeding at the time of endoscopy or colonoscopy; and blood within the stomach at endoscopy or colonoscopy. The symptom(s) had to be accompanied by a decrease of >1 g/dl in the patient's hemoglobin level. The location of the bleeding was identified as upper GI tract, lower GI tract or both according to esophagogastroduodenoscopy, colonoscopy, small-bowel enteroscopy or mesenteric angiography. Post-LVAD implantation anti-coagulation therapy consisted of warfarin, aspirin and dipyridamole. Thirty-two of the 172 patients (19%) had GI bleeding after 63 ± 62 (range 8 to 241) days of HMII support. Ten patients had GI bleeding from an AVM; these included 3 patients who had 2 bleeding episodes and 2 patients who had 5 episodes each. Sixteen patients had upper GI bleeding (10 hemorrhagic gastritis, 4 gastric AVM, 2 Mallory-Weiss syndrome), 15 had lower GI bleeding (6 diverticulosis, 6 jejunal AVM, 1 drive-line erosion of the colon, 1 sigmoid polyp, 1 ischemic colitis) and 1 had upper and lower GI bleeding (1 colocutaneous and gastrocutaneous fistula). All GI bleeding episodes were successfully managed medically. Arteriovenous malformations can cause GI bleeding in patients with continuous-flow LVADs. In all cases in this series, GI bleeding was successfully managed without the need for surgical intervention.
    The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation 04/2011; 30(8):849-53. · 3.54 Impact Factor
  • Article: Left stellate ganglion block for continuous ventricular arrhythmias during percutaneous left ventricular assist device support.
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    ABSTRACT: A 58-year-old man presented with chest pain and tightness and was diagnosed with a Q-wave anterior myocardial infarction. He then developed pulseless ventricular arrhythmias, which were treated with repeated direct-current shocks and intravenous amiodarone. He underwent emergency cardiac catheterization: stents were deployed in the left anterior descending coronary artery and right coronary artery, and an intra-aortic balloon pump was inserted. Severe refractory cardiogenic shock and incessant ventricular arrhythmias compelled us to place a TandemHeart percutaneous left ventricular assist device 4 hours later. The patient's hemodynamic status stabilized, but the arrhythmias persisted for 36 hours. Multiple doses of intravenous amiodarone and lidocaine and multiple external direct-current shocks were all tried, but these measures failed to terminate the life-threatening ventricular arrhythmias. We performed a pharmacologic block of the left stellate ganglion, and this resulted in a return to sinus rhythm after 1 direct-current shock. To our knowledge, this is the 1st patient with refractory ventricular arrhythmias to have been treated with TandemHeart support and left stellate ganglion block.
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2011; 38(4):409-11. · 0.65 Impact Factor
  • Article: Extracorporeal membrane oxygenation with hemoconcentration: in a hypervolemic patient with critical aortic stenosis.
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    ABSTRACT: Herein, we describe the case of a 60-year-old man with severe nonischemic cardiomyopathy and hypervolemia. By means of venoarterial extracorporeal membrane oxygenation at the bedside, along with hemoconcentration, the patient was resuscitated from severe cardiogenic shock and normal blood volume was restored. Within 24 hours, he was able to undergo a high-risk aortic valve replacement for severe aortic stenosis, with a successful outcome. To our knowledge, this is the first reported case in which hemoconcentration with extracorporeal membrane oxygenation has been used to support a patient with severe hypervolemia.
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2011; 38(5):565-7. · 0.65 Impact Factor
  • Article: Diaphragmatic implantation of the HeartWare ventricular assist device.
    Igor D Gregoric, William E Cohn, O H Frazier
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    ABSTRACT: The HeartWare (HeartWare Inc., Framingham, MA) ventricular assist device (HVAD) is designed to be implanted with the pump in the pericardial space and its integrally attached inflow cannula in the left ventricle. The uniquely incorporated inflow cannula was originally designed to be inserted into the diaphragmatic surface of the heart, allowing the pump to sit on the flattened diaphragmatic surface. Commonly, however, the inflow cannula is placed through the usual left ventricular assist device insertion site, anterolateral to the left ventricular apex. We describe the original, intended technique for inflow cannula insertion and HVAD placement on the diaphragmatic surface of the left ventricle. Our experience has confirmed that this placement results in the optimal left ventricular position, with orientation of the inlet cannula parallel to the short axis of the left ventricle and anterior to the papillary muscle insertion. This approach should protect against inflow obstruction and endocardial contact, with resulting arrhythmias. In addition, this position results in lateral placement of the outflow graft, avoiding the anterior and retrosternal surface of the right ventricle.
    The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation 01/2011; 30(4):467-70. · 3.54 Impact Factor
  • Article: Modification of a volume-overload heart failure model to track myocardial remodeling and device-related reverse remodeling.
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    ABSTRACT: Purpose. To provide an ovine model of ventricular remodeling and reverse remodeling by creating congestive heart failure (CHF) and then treating it by implanting a left ventricular assist device (LVAD). Methods. We induced volume-overload heart failure in 2 sheep; 20 weeks later, we implanted an LVAD and assessed recovery 11 weeks thereafter. We examined changes in histologic and hemodynamic data and levels of cellular markers of CHF. Results. After CHF induction, we found increases in LV end-diastolic pressure, LV systolic and diastolic dimensions, wall thickness, left atrial diameter, and atrial natriuretic protein (ANP) and endothelin-1 (ET-1) levels; β-adrenergic receptor (BAR) and dystrophin expression decreased markedly. Biopsies confirmed LV remodeling. After LVAD support, LV systolic and diastolic dimensions, wall thickness, and mass, and ANP and ET-1 levels decreased. Histopathologic and hemodynamic markers improved, and BAR and dystrophin expression normalized. Conclusions. We describe a successful sheep model for ventricular and reverse remodeling.
    ISRN cardiology. 01/2011; 2011:831062.
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    Article: The percutaneous ventricular assist device in severe refractory cardiogenic shock.
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    ABSTRACT: We evaluated the efficacy and safety of the percutaneous ventricular assist device (pVAD) in patients in severe refractory cardiogenic shock (SRCS) despite intra-aortic balloon pump (IABP) and/or high-dose vasopressor support. SRCS is associated with substantial mortality despite IABP counterpulsation. Until recently, there was no rapid, minimally invasive means of providing increased hemodynamic support in SRCS. A total of 117 patients with SRCS implanted with TandemHeart pVAD (CardiacAssist, Inc., Pittsburgh, Pennsylvania) were studied, of whom 56 patients (47.9%) underwent active cardiopulmonary resuscitation immediately before or at the time of implantation. Data was collected regarding clinical characteristics, hemodynamics, and laboratory values. Eighty patients had ischemic and 37 patients had nonischemic cardiomyopathy. The average duration of support was 5.8 ± 4.75 days. After implantation, the cardiac index improved from median 0.52 (interquartile range [IQR]: 0.8) l/(min·m(2)) to 3.0 (IQR:0.9) l/(min·m(2)) (p < 0.001). The systolic blood pressure and mixed venous oxygen saturation increased from 75 (IQR:15) mm Hg to 100 (IQR:15) mm Hg (p < 0.001) and 49 (IQR:11.5) to 69.3 (IQR:10) (p < 0.001), respectively. The urine output increased from 70.7 (IQR: 70) ml/day to 1,200 (IQR: 1,620) ml/day (p < 0.001). The pulmonary capillary wedge pressure, lactic acid level, and creatinine level decreased, respectively, from 31.53 ± 10.2 mm Hg to 17.29 ± 10.82 mm Hg (p < 0.001), 24.5 (IQR: 74.25) mg/dl to 11 (IQR: 92) mg/dl (p < 0.001), and 1.5 (IQR: 0.95) mg/dl to 1.2 (IQR: 0.9) mg/dl (p = 0.009). The mortality rates at 30 days and 6 months were 40.2% and 45.3%, respectively. The pVAD rapidly reversed the terminal hemodynamic compromise seen in patients with SRCS refractory to IABP and vasopressor support.
    Journal of the American College of Cardiology 10/2010; 57(6):688-96. · 14.16 Impact Factor
  • Article: Endomyocardial nodular calcification as a cause of heart failure.
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    ABSTRACT: Massive cardiac calcification is rare, occurring in association with chronic diseases or more commonly with previous myocardial infarction. We present an intriguing case of massive myocardial calcification of the left ventricle in a young patient with restrictive cardiomyopathy and progressive heart failure who required transplantation. The patient's history and clinical presentation did not reveal the etiology of the myocardial calcification.
    Cardiovascular pathology: the official journal of the Society for Cardiovascular Pathology 10/2010; 20(5):e185-8. · 1.63 Impact Factor
  • Article: Iatrogenic double-chambered left atrium: created during left ventricular assist device implantation.
    Zumrut T Demirozu, Igor D Gregoric, O H Frazier
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2010; 37(6):725. · 0.65 Impact Factor
  • Article: Perigraft hemorrhage after abdominal aortic aneurysm repair in a heart transplant patient.
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    ABSTRACT: Spontaneous perigraft hemorrhage can occur years after a successful aortic aneurysm repair. Such hemorrhage can result, in part, from inadequate graft healing. Herein, we describe the case of a heart transplant recipient who underwent an abdominal aortic aneurysm repair that was complicated by an acute perigraft leak 6 weeks later. Apparently, suppression of the patient's immune system impaired proper healing of the graft-aortic anastomosis site. In patients who have a compromised immune system, an additional 4-0 polypropylene pledgeted suture line should be placed for reinforcement during abdominal aortic aneurysm repair. Postoperatively, patients who are given immunosuppressive therapy should undergo careful, long-term monitoring.
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2010; 37(5):572-3. · 0.65 Impact Factor
  • Article: TandemHeart as a rescue therapy for patients with critical aortic valve stenosis.
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    ABSTRACT: We analyzed our use of the TandemHeart Percutaneous Ventricular Assist Device (Cardiac Assist Inc, Pittsburgh, PA) as a rescue therapy for patients with cardiac arrest or severe refractory cardiogenic shock (SRCS) before or after aortic valve replacement (AVR) for critical aortic valve stenosis. We reviewed the records of 10 patients (6 men; 4 women), aged 62 +/- 12 years, who presented with cardiac arrest or SRCS. Eight patients, 5 undergoing cardiopulmonary resuscitation (CPR) and 3 with SRCS, received TandemHeart support in the catheterization laboratory and had AVR after undergoing hemodynamic stabilization. The other 2 patients went directly to the operating room while undergoing CPR, for emergency AVR and received the device for postcardiotomy cardiogenic shock. All 10 patients were intubated, on maximal vasopressor support, and 7 had an intraaortic balloon pump. The preoperative Society of Thoracic Surgeons mortality risk was 74.9% +/- 24.5%. The 8 patients who received the TandemHeart in the catheterization laboratory were supported for 6.4 +/- 3.8 days and had significantly improved renal function before AVR. One patient died of sepsis 34 days after AVR, The other 7 were discharged home (ejection fraction, 0.42 +/- 0.14) and were alive 2 to 43 months later. The 2 patients who received the device in the operating room after AVR died on days 8 and 21, respectively. Prompt placement of the TandemHeart in these critically ill patients yields the shortest "emergency department door to left ventricular unloading time," improves end-organ function, and allows AVR to be performed electively.
    The Annals of thoracic surgery 12/2009; 88(6):1822-6. · 3.74 Impact Factor
  • Article: The 'left' ventricle during pulsatile mechanical assistance: reliability of cardiac output monitoring with an uncalibrated pulse contour method.
    European Heart Journal 10/2009; 31(2):148. · 10.48 Impact Factor

Institutions

  • 2003–2012
    • Texas Heart Institute
      Houston, TX, USA
    • University of Texas Medical School
      • Department of Cardiothoracic and Vascular Surgery
      Houston, TX, USA
  • 2007–2010
    • Baylor College of Medicine
      • Department of Medicine
      Houston, TX, USA
    • Università degli Studi di Siena
      Siena, Tuscany, Italy
  • 2008–2009
    • Ljubljana University Medical Centre
      • Department of Cardiovascular Surgery
      Ljubljana, Ljubljana, Slovenia
    • The Methodist Hospital System
      • Department of Cardiovascular Surgery
      Houston, TX, USA