Michael P Siegenthaler

The Ottawa Hospital, Ottawa, Ontario, Canada

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Publications (61)127.86 Total impact

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    ABSTRACT: The aim of this study was to compare our experience between open and video-assisted thoracic surgery (VATS) approaches to the management of thoracic effusions in ventricular assist device (VAD) patients. This was a retrospective review of a prospectively collected database of VAD patients at a single institution. Patients who were operated on for pericardial and/or pleural effusions were included. Primary outcomes included operative mortality and morbidity as well as effusion recurrence. From 1993 to 2009, 360 adult patients underwent VAD placement. Twenty-three patients (11.9%) required operative management of pleural (n = 24), pericardial (n = 13) or both pleural and pericardial (n = 6) effusions [open = 20 (47%); VATS = 23 (53%)]. Drainage with decortication was performed in five patients, with the remaining undergoing drainage alone. Open and VATS patients were similar in age, gender and indication for VAD support. Conversion from VATS to open was necessary in four patients (17%). There was no operative mortality and no difference in perioperative complications between approaches. The open and VATS approaches had similar rates of pleural (open = 63%; VATS = 41%; P = 0.42) and pericardial (open = 31%; VATS = 17%; P = 1) effusion recurrences. In spite of apparent challenges, the VATS approach may be as safe and effective as open surgery for the management of pleural and pericardial effusions in VAD patients in centres with significant minimally invasive thoracic experience.
    Interactive Cardiovascular and Thoracic Surgery 11/2011; 14(1):44-7. · 1.11 Impact Factor
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    ABSTRACT: Mechanical circulatory support (MCS) is life sustaining for patients with end-stage heart failure. Most devices require abdominal wall transgression, creating a potential for abdominal complications. The incidence and impact of these relatively underreported complications are unknown. A retrospective review was performed on 179 patients who received MCS therapy from 1999 to 2008. Abdominal complications were grouped as abdominal wall, gastrointestinal tract, and solid organ. Ninety-eight patients (55%) experienced 157 abdominal complications. These involved the abdominal wall in 69 (44%), the gastrointestinal tract in 52 (33%), and the solid organs in 36 (23%). Surgical intervention was required in 36% of patients with abdominal wall complications, 19% of patients with gastrointestinal tract complications, and 14% of patients with solid organ complications. Multivariate analysis identified diabetes mellitus (p < 0.001), emergent device placement (p = 0.019), and preimplant mechanical ventilation (p = 0.045) as independent risk factors for developing an abdominal complication. Kaplan-Meier survival while receiving MCS was significantly reduced for patients with abdominal complications versus those without (p = 0.0142). Multivariate analysis identified only solid organ abdominal complications (p = 0.001) as an independent risk factor for death while receiving device support. Abdominal complications are common in patients supported with MCS devices and significantly reduce survival. Surgical intervention is more frequently required for complications related to the abdominal wall compared with other complications. Patients with significant comorbidities (diabetes mellitus, respiratory failure) requiring urgent or emergent device placement are at higher risk for the development of abdominal complications with an attendant reduction in device-related survival.
    The Annals of thoracic surgery 02/2010; 89(2):522-8; discussion 528-9. · 3.45 Impact Factor
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    ABSTRACT: Short-term mechanical circulatory support may be lifesaving in patients with right ventricular (RV) failure related to post-cardiotomy cardiogenic shock (PCCS), cardiac transplantation (CTx), and long-term therapy with a left ventricular assist device (LVAD). This study evaluates our clinical experience using the CentriMag (Levitronix LLC, Waltham, Mass) system for temporary mechanical RV support. A retrospective review was performed of 29 patients (mean age, 57 +/- 14 years) in whom the CentriMag system was used for RV support from September 2005 to March 2008. The indication for RV support was PCCS in 7 (24%), CTx in 10 (35%), and LVAD placement in 12 (41%). The mean support time was 8 +/- 8 days. The device was successfully weaned in 3 PCCS patients (43%), 7 CTx patients (70%), and 7 LVAD patients (58%). Complications included major infection (pneumonia, sepsis, or LVAD pocket infection) in 13 (45%), arrhythmia in 13 (45%), reoperation for bleeding in 10 (35%), stroke/encephalopathy in 3 (10%), and air embolism in 1 (3%). Early mortality (< 30 days or before discharge) occurred in 14 patients (48%) of which 9 (31%) died with the device in place. Late death occurred in 2 of 15 patients (13%) who survived to discharge. There were no device failures. The CentriMag system provides effective temporary mechanical circulatory support for RV failure. Ease of implantation and a high rate of successful device weaning justify the use of the CentriMag system for temporary RV support.
    The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation 10/2009; 28(9):971-6. · 3.54 Impact Factor
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    ABSTRACT: Although ventricular assist devices (VADs) provide effective treatment for end-stage heart failure, VAD support remains associated with significant risk for adverse events (AEs). To date there has been no detailed assessment of the incidence of a full range of AEs using standardized event definitions. We sought to characterize the frequency and timing of AE onset during the first 60 days of VAD support, a period during which clinical observation suggests the risk of incident AEs is high. A retrospective analysis was performed utilizing prospectively collected data from a single-site clinical database including 195 patients aged 18 or greater receiving VADs between 1996 and 2006. Adverse events were coded using standardized criteria. Cumulative incidence rates were determined, controlling for competing risks (death, transplantation, recovery-wean). During the first 60 days after implantation, the most common AEs were bleeding, infection, and arrhythmias (cumulative incidence rates, 36% to 48%), followed by tamponade, respiratory events, reoperations, and neurologic events (24% to 31%). Other events (eg, hemolysis, renal, hepatic events) were less common (rates <15%). Some events (eg, bleeding, arrhythmias) showed steep onset rates early after implantation. Others (eg, infections, neurologic events) had gradual onsets during the 60-day period. Incidence of most events did not vary by implant era (1996 to 2000 vs 2001 to 2006) or by left ventricular versus biventricular support. Understanding differential temporal patterns of AE onset will allow preventive strategies to be targeted to the time periods when specific AE risks are greatest. The AE incidence rates provide benchmarks against which future studies of VAD-related risks may be compared.
    The Annals of thoracic surgery 10/2009; 88(4):1162-70. · 3.45 Impact Factor
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    ABSTRACT: We tested the hypothesis that a miniaturised axial flow pump with infection-resistant power delivery could improve longevity and quality of life (QOL) in advanced heart failure patients deemed unsuitable for transplantation. The study included all non-United States Jarvik 2000 patients (n=46), where a skull-pedestal-based power line was employed with the intention of long-term support. Patient age ranged from 29 to 80 years. Of the 46 patients, 42 were male. All were New York Heart Association (NYHA) IV predominantly with idiopathic dilated (n=22) or ischaemic (n=18) cardiomyopathy. The experience (2000-2008) included the learning curve of 10 centres. The internal components are imperceptible. The power/control system is user friendly, allowing excellent QOL. There has been no pump malfunction. The Kaplan-Meier survival analysis is shown. The longest event-free survival is 7.5 years. Support exceeded 3 years in five cases. The cumulative experience exceeds 50 years. Three patients were transplanted, and two pumps were replaced at 90 and 203 days. Nineteen cases are ongoing (mean: 663 days), while 22 died during support (mean survival: 402 days), of which five from non-device-related diseases. Temporary local infection occurred in three pedestals, and there has been no pump infection. Incidence of thrombo-embolic events showed wide variation between centres. From this learning-curve experience, both left ventricular assist device (LVAD) and power delivery are reliable and promising for destination therapy. Early mortality is similar to other studies and relates to the severity of illness. Pump infection has not occurred and prolonged event-free survival is clearly possible with expert medical management.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 08/2009; 37(2):350-6. · 2.40 Impact Factor
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    ABSTRACT: The Jarvik 2000 (Jarvik Heart, Inc, New York, NY) is a thumb-sized high-speed impeller pump that is used as a ventricular assist device in patients with terminal heart failure. Because the Jarvik 2000 is designed for long-term use, it is a central question whether the mechanical forces inside the pump affect blood components. This study evaluated the potential association of the high rotational speed of the Jarvik 2000 with platelet activation, which may result in thromboembolic events. The study group comprised patients with terminal heart failure who were supported with the Jarvik 2000. All were men and received 100 mg aspirin daily. In 8 patients, soluble platelet activation markers (P-selectin and sCD40L), platelet counts, and hemolysis markers (haptoglobin and lactate dehydrogenase levels) were determined. In 5 patients, P-selectin expression and platelet receptor glycoprotein IIb/IIIa activation were determined with flow cytometry and compared with a control group of 5 healthy men. Platelet activation was measured at various rotational device speeds. After Jarvik 2000 implantation, increased hemolysis was observed, but platelet activation markers and platelet counts were not affected. Increased rotational speed (8000 to 12,000 rpm) of the device also did not result in increased platelet activation. The Jarvik 2000 was not associated with detectable platelet activation, despite high rotational impeller speeds.
    The Journal of thoracic and cardiovascular surgery 04/2009; 137(3):736-41. · 3.41 Impact Factor
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    ABSTRACT: Conventional surgical therapy of aortic arch aneurysms consists of aortic arch replacement requiring cardiopulmonary bypass and deep hypothermic circulatory arrest. This method is associated with significant morbidity and mortality, mainly due to neurologic complications and the sequelae of deep hypothermic circulatory arrest. Thus, it makes sense to work on developing less invasive surgical techniques. Surgical aortic arch de-branching is required before the supra-aortic vessels can be safely covered by an endovascular stent graft. We describe how the supra-aortic vessels can best be revascularized, followed by complete coverage of the aortic arch with endovascular stent grafts. We hereby present our case selection criteria, preoperative work-up, and surgical approach for aortic arch de-branching with supra-aortic revascularization, followed by complete coverage of the aortic arch by endovascular stent grafting. This technique's safeguards and pitfalls are described for a cohort of 26 patients. Endovascular aortic arch repair after aortic arch de-branching has the potential to lower the morbidity and mortality rates in patients with aortic arch diseases.
    The Annals of thoracic surgery 03/2009; 87(2):603-7. · 3.45 Impact Factor
  • Journal of Heart and Lung Transplantation - J HEART LUNG TRANSPLANT. 01/2009; 28(2).
  • Journal of Heart and Lung Transplantation - J HEART LUNG TRANSPLANT. 01/2009; 28(2).
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    Michael P Siegenthaler, Friedhelm Beyersdorf
    Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 01/2009; 36(5):446-8. · 0.67 Impact Factor
  • Journal of Heart and Lung Transplantation - J HEART LUNG TRANSPLANT. 01/2009; 28(2).
  • Journal of Heart and Lung Transplantation - J HEART LUNG TRANSPLANT. 01/2009; 28(2).
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    Journal of Heart and Lung Transplantation - J HEART LUNG TRANSPLANT. 01/2009; 28(2).
  • Journal of Heart and Lung Transplantation - J HEART LUNG TRANSPLANT. 01/2009; 28(2).
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    ABSTRACT: Left ventricular assist device (LVAD) support may facilitate myocardial recovery. We evaluated the impact of LVAD support on Fas expression in a cohort with end-stage heart failure. Myocardial gene expression was assessed pre- and post-LVAD by RNase protection assay and compared to control donor hearts. The expression of Fas is markedly elevated at the time of LVAD support and is tightly correlated with TNF expression. While interleukin (IL)-6 was significantly reduced by LVAD support, the impact of support on Fas was highly variable and tightly linked to tumor necrosis factor (TNF). The role of Fas in predicting recovery after LVAD support requires further investigation.
    Clinical and Translational Science 12/2008; 1(3):245-8. · 2.33 Impact Factor
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    ABSTRACT: Endovascular treatment of thoracoabdominal aortic aneurysms (TAAA) in combination with selective open surgical revascularization may be an alternative to conventional surgical repair. We analyzed our patient outcomes after elective and emergent endovascular TAAA repair. Mortality and outcome data from 21 consecutive patients treated with endovascular TAAA repair between 2000 and 2006 were reviewed. An integrated neuroprotective approach was used on all patients. Mortality risk estimates for open surgery (OS) were calculated using the published risk assessment models and compared to our outcomes. Of the 21 patients, 9 had acute presentation: acute pain (9), rupture (6), and malperfusion (1). The celiac axis was overstented in 15. Nine hybrid open surgical procedures were performed: visceral/renal arteries (5), infrarenal aorta (3) and complete arch revascularization (1). Eleven patients had previous aortic surgery. Thirty-day mortality rate was 4.8% (1/21, predicted OS value 8.3%), 1-, 2- and 3-year survival was 80%. One hospital death occurred due to ischemic colitis after inferior mesenteric artery overstenting. No patient with acute presentation died during the initial hospital admission. There was no paraplegia (predicted OS rate 11.46%) and one event of delayed temporary paraparesis 3 weeks after hospital discharge corrected with raising the blood pressure. Other neurologic complications included one minor left pontine stroke with complete resolution, postoperative confusion (1) and saphenous nerve injury (1). No new late endoleaks occurred after initial complete aneurysm exclusion. Five patients underwent early (<30 days) and four patients underwent late endovascular reinterventions for persistent endoleak. An additional reintervention included percutaneous stenting of a superior mesenteric artery stenosis. Actual freedom from late reintervention was 81%, and 76% at 1-, 2 and 3-year follow-up. Late major adverse events included one stent infection leading to multi-organ failure and death. Endovascular treatment of thoracoabdominal aneurysms with selective visceral and renal revascularization is associated with low mortality and can only be effectively performed by a surgeon. High-risk patients and those with acute presentation appear to benefit most from this therapy. Early results up to three years of this therapy are encouraging, but further follow up to validate long-term results is required.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 09/2008; 34(4):810-9. · 2.40 Impact Factor
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    ABSTRACT: Graft collapse is a known complication of thoracic aortic stent grafting, particularly in cases of traumatic thoracic aortic transection, when a typically smaller diameter aorta is repaired with a relatively large diameter device. In contrast, obstruction of the aorta from a stent graft that protrudes into the aortic arch but does not collapse is a less common complication of thoracic aortic stent grafting that can present as a functional aortic coarctation. We describe here two cases of physiologic coarctation of the aorta caused by stent graft protrusion into the arch that were successfully treated with stent graft explantation and open aortic reconstruction.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 08/2008; 48(4):1007-11. · 3.52 Impact Factor
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    ABSTRACT: Dilatation of the aorta at the landing zone site may be exaggerated by the radial force of stent grafts potentially limiting long-term results of endovascular therapy. We evaluated growth patterns and morphology of the thoracic aorta in young piglets after thoracic stent-graft placement. Eight domestic piglets (37+/-2 kg) had an endovascular stent graft placed in the proximal descending thoracic aorta using retroperitoneal access. At implantation, the stent was oversized by 10%. Aortic size was documented after thoracotomy by intraoperative measurement and angiography. Subsequently the piglets were grown to adult size (181+/-42 kg). At explantation 6-15 months later, CT scan and surgical evaluation for endoleaks, defined as perigraft flow, was performed. Histopathological assessment of the explanted aorta was performed in stented and non-stented segments and compared to five normal porcine aortas. No endoleak (perigraft flow) or stent migration occurred even in 230kg pigs. The stent grafts expanded to full size, but there was no further growth in the stented area. The aortic diameter increased significantly by 32+/-9% 1cm proximal to the stents (p=0.0012) and by 45+/-13% 1cm distal to the stents (p=0.0033). The stented area grew less than the proximal (p=0.0011) and distal aorta (p<0.0001). In all pigs, the distal aorta was larger than the proximal overstented segment. Histology of the stented aorta showed significant thickening of the intima (p=0.018) and media (p=0.006) with neointimal formation and segmental fibrosis of the inner 1/3 of the media with loss of smooth muscle cells and compression of the elastic fibers but normal architecture in the outer 2/3 of the media. Endovascular stent grafting may inhibit growth of the nonatherosclerotic normal aorta and lead to intimal hyperplasia and focal fibrosis in the inner media part adjacent to the stent. Stent-graft interaction with aortic tissue over time is important and should receive more detailed evaluation. Testing this interaction in an animal model of nonatherosclerotic dilative aortic disease could be of great interest.
    European Journal of Cardio-Thoracic Surgery 07/2008; 34(1):17-24. · 2.67 Impact Factor
  • Journal of Cardiac Failure - J CARD FAIL. 01/2008; 14(6).
  • Journal of Heart and Lung Transplantation - J HEART LUNG TRANSPLANT. 01/2008; 27(2).

Publication Stats

520 Citations
127.86 Total Impact Points

Institutions

  • 2011
    • The Ottawa Hospital
      • Division of Thoracic Surgery
      Ottawa, Ontario, Canada
  • 2009–2011
    • University of Pittsburgh
      Pittsburgh, Pennsylvania, United States
    • Johannes Gutenberg-Universität Mainz
      • Department of Cardiothoracic and Vascular Surgery
      Mainz, Rhineland-Palatinate, Germany
  • 2002–2009
    • University of Freiburg
      Freiburg, Baden-Württemberg, Germany
  • 2005–2007
    • Universitätsklinikum Freiburg
      Freiburg an der Elbe, Lower Saxony, Germany