Postoperative acute kidney injury following intraoperative blood product transfusions during cardiac surgery.

INTRODUCTION: This study explored the nature of the association between intraoperative usage of red blood cell, fresh frozen plasma, cryoprecipitate or platelet transfusions and acute kidney injury. METHODS: A total of 1175 patients who underwent cardiac surgery between 2008 and 2013 were retrospectively analyzed. We assessed the association between: (1) preoperative patient characteristics and acute kidney injury, (2) intraoperative blood product usage and acute kidney injury, (3) acute kidney injury and 30-day mortality or re-hospitalization. RESULTS: In our cohort of 1175 patients, 288 patients (24.5%) developed acute kidney injury. This included 162 (13.8%), 69 (5.9%) and 57 (4.9%) developing stage 1, stage 2 or stage 3 acute kidney injury, respectively. Increased red blood cell, fresh frozen plasma or platelet transfusions increased the odds of developing acute kidney injury. Specifically, every unit of red blood cells, fresh frozen plasma or platelets transfused was associated with an increase in the covariate-adjusted odds ratio of developing ⩾ stage 2 kidney injury of 1.18, 1.19 and 1.04, respectively. CONCLUSIONS: Intraoperative blood product transfusions were independently associated with an increased odds of developing acute kidney injury following cardiac surgery. Further randomized studies are needed to better define intraoperative transfusion criteria.

A complicated case of vascular Pythium insidiosum infection treated with limb-sparing surgery.

INTRODUCTION: Pythiosis is a serious life- and limb-threatening infection endemic to Thailand, but rarely seen in the Western hemisphere. Here, we present a unique case of vascular pythiosis initially managed with limb-sparing vascular bypass grafts complicated by a pseudoaneurysm in our repair. PRESENTATION OF CASE: The patient is a 17 year-old Jamaican male with severe aplastic anemia. He sustained a minor injury to his left leg while fishing in Jamaica, which evolved to become an exquisitely tender inguinal swelling. His physical exam and imaging were significant for arteriovenous fistula with limb ischemia. Pathology obtained during surgery for an extra-anatomic vascular bypass showed extensive invasion by Pythium insidiosum. He later developed a pseudoaneurysm at the site of proximal anastomosis and required urgent intervention. DISCUSSION: This patient presented with a rare, but classic case of vascular pythiosis, which was unrecognized at the time of presentation. A variety of therapeutic modalities have been used to treat this disease, including antibiotics, antifungals, and immunotherapy, but the ultimate management of vascular pythiosis is surgical source control. CONCLUSION: A high index of suspicion in susceptible patients is needed for timely diagnosis of vascular pythiosis to achieve optimal source control.

Hemodynamic Consequences of Hypertrophic Cardiomyopathy with Midventricular Obstruction: Apical Aneurysm and Thrombus Formation.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) with midventricular hypertrophy is an uncommon phenotypic variant of the disease. Midventricular hypertrophy predisposes to intracavitary obstruction and downstream hemodynamic sequelae. CASE REPORT: We present a case of HCM with midventricular hypertrophy and obstruction diagnosed after a CT scan of the abdomen incidentally revealed a filling defect in the left ventricular apex. Transthoracic echocardiography demonstrated mid left ventricular hypertrophy and obstruction, as well as an aneurysmal apex containing a large thrombus. Cardiovascular MRI showed a spade-shaped left ventricle with midcavitary obliteration, an infarcted apex and regions of myocardial fibrosis. Due to the risk of embolization and a relative contraindication to anticoagulation, the patient underwent surgery including thrombectomy, septal myectomy and aneurysmal ligation. CONCLUSIONS: Hypertrophic cardiomyopathy with midventricular hypertrophy leads to cavity obstruction, increased apical wall tension, ischemia and ultimately fibrosis. Over time, patchy apical fibrosis can develop into a confluent scar resembling a transmural myocardial infarction in the left anterior descending coronary artery distribution. Aneurysmal remodeling of the left ventricular apex potentiates thrombus formation and risk of cardioembolism. For these reasons, hypertrophic cardiomyopathy with midventricular obstruction portends a particularly poor prognosis and should be recognized early in the disease process.

The universal bed model for patient care improves outcome and lowers cost in cardiac surgery.

OBJECTIVE: With the escalating demands to increase the efficiency and decrease the cost, innovations in postoperative cardiac surgical patient care are needed. The universal bed model is an innovative care delivery system that allows patient care to be managed in one setting from postoperation to discharge. We hypothesized that the universal bed model in the context of cardiac surgery would improve outcomes and efficacy. METHODS: A total of 610 consecutive patients were admitted to the universal bed unit and prospectively entered into the Society of Thoracic Surgeons National Cardiac Database. Intensive care unit level of care was determined by acuity and staffing needs. Telemetry was employed from admission to discharge, and multidisciplinary rounds were conducted twice daily. Postoperative outcomes were recorded during hospital stay, and comparisons were made with the Society of Thoracic Surgeons National Cardiac Database using identical variables over the same period of time. RESULTS: Decreased ventilation time, intensive care unit and hospital stay, and reduction in the incidence of atrial fibrillation and infectious complications yielded a financial benefit in the universal bed group compared with the traditional model of admission. Stroke rate and in-hospital mortality were the same compared with regional and national centers. Compared with regional centers, there was an average cost savings between $6200 and $9500 per patient depending on the operation. Patient care satisfaction by independent survey was in the 99th percentile. CONCLUSIONS: The universal bed patient care model allows for expedient and efficacious care as measured by decreased length of intensive care unit and hospital stay, improved postoperative outcomes, patient satisfaction, and cost savings.

Minimally invasive approach to thoracic effusions in patients with ventricular assist devices.

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.

NT5E mutations and arterial calcifications.

BACKGROUND: Arterial calcifications are associated with increased cardiovascular risk, but the genetic basis of this association is unclear. METHODS: We performed clinical, radiographic, and genetic studies in three families with symptomatic arterial calcifications. Single-nucleotide-polymorphism analysis, targeted gene sequencing, quantitative polymerase-chain-reaction assays, Western blotting, enzyme measurements, transduction rescue experiments, and in vitro calcification assays were performed. RESULTS: We identified nine persons with calcifications of the lower-extremity arteries and hand and foot joint capsules: all five siblings in one family, three siblings in another, and one patient in a third family. Serum calcium, phosphate, and vitamin D levels were normal. Affected members of Family 1 shared a single 22.4-Mb region of homozygosity on chromosome 6 and had a homozygous nonsense mutation (c.662C→A, p.S221X) in NT5E, encoding CD73, which converts AMP to adenosine. Affected members of Family 2 had a homozygous missense mutation (c.1073G→A, p.C358Y) in NT5E. The proband of Family 3 was a compound heterozygote for c.662C→A and c.1609dupA (p.V537fsX7). All mutations found in the three families result in nonfunctional CD73. Cultured fibroblasts from affected members of Family 1 showed markedly reduced expression of NT5E messenger RNA, CD73 protein, and enzyme activity, as well as increased alkaline phosphatase levels and accumulated calcium phosphate crystals. Genetic rescue experiments normalized the CD73 and alkaline phosphatase activity in patients' cells, and adenosine treatment reduced the levels of alkaline phosphatase and calcification. CONCLUSIONS: We identified mutations in NT5E in members of three families with symptomatic arterial and joint calcifications. This gene encodes CD73, which converts AMP to adenosine, supporting a role for this metabolic pathway in inhibiting ectopic tissue calcification. (Funded by the National Human Genome Research Institute and the National Heart, Lung, and Blood Institute of the National Institutes of Health.).

Impact of abdominal complications on outcome after mechanical circulatory support.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Destination therapy with a rotary blood pump and novel power delivery.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Incidence and patterns of adverse event onset during the first 60 days after ventricular assist device implantation.

BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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.

Evaluation of platelet activation in patients supported by the Jarvik 2000* high-rotational speed impeller ventricular assist device.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: The Jarvik 2000 was not associated with detectable platelet activation, despite high rotational impeller speeds.

Endovascular aortic arch repair after aortic arch de-branching.

PURPOSE: 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. DESCRIPTION: 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. EVALUATION: 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. CONCLUSIONS: 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.

Endovascular treatment for thoracoabdominal aneurysms: outcomes and results.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Physiologic coarctation of the aorta resulting from proximal protrusion of thoracic aortic stent grafts into the arch.

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.

Thoracic endovascular stent grafting inhibits aortic growth: an experimental study.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Myocardial Fas and cytokine expression in end-stage heart failure: impact of LVAD support.

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.

Incidence of neurological complications following overstenting of the left subclavian artery.

OBJECTIVE: Aortic endovascular stent-graft implantation is associated with low morbidity and mortality rates. Overstenting of the left subclavian artery may be necessary to create a satisfactory proximal 'landing zone' for the stent-graft. Few cases have been published reporting adverse neurological events after overstenting of the left subclavian artery. We thus evaluated whether this procedure is associated with a higher rate of neurological complications by focusing on the management of the supra-aortic vessels. METHODS: Twenty patients suffering from aortic arch aneurysms (n=3), descending aortic aneurysms (n=7), acute (n=6) and chronic (n=4) type-B aortic dissections underwent stent-graft repair with complete (n=14) or partial (n=6) overstenting of the left subclavian artery. Three patients underwent overstenting of the entire aortic arch with ascending aortic-bi-carotid bypass grafting. One patient with right carotid and vertebral artery occlusion underwent initial carotid-to-subclavian bypass. All patients subsequently underwent neurological examination and Doppler ultrasound for detection of neurological and peripheral vascular complications. RESULTS: Aortic stent-graft repair was successful in all patients without acute neurologic complications. Two patients developed late central adverse neurological events: right-sided vertebral artery occlusion with brainstem infarction (n=1) and impaired binocular vision combined with dizziness (n=1), necessitating secondary subclavian transposition in one patient. Peripheral symptoms related to occlusion of the left subclavian artery were observed in five patients as sensory and motoric deficits of the left hand and arm. CONCLUSIONS: Overstenting of the left subclavian artery as treatment of aortic pathologies in high-risk patients is feasible but associated with the risk of neurological complications and peripheral symptoms. Side effects were mild or transient in most of our patients. Detailed preoperative exploration of vascular anatomy and pathology via Doppler ultrasound, CT- or MRI scan is mandatory to avoid adverse neurological events. Prior surgical revascularization of the left subclavian artery is essential in patients with high-grade stenoses, occlusions, or anatomic variants of the supra-aortic branches. Delayed surgical revascularization is necessary only in patients with relevant subclavian steal syndrome or severe peripheral vascular symptoms.

Perioperative management to improve neurologic outcome in thoracic or thoracoabdominal aortic stent-grafting.

BACKGROUND: Thoracic or thoracoabdominal aortic stent-graft repair has shown a reduction in morbidity and mortality rates due to the procedure's advantages (no aortic cross-clamping, continuous distal aortic perfusion, no reperfusion injury). However, 3% to 12% of the patients are at risk of spinal cord ischemia. We investigated spinal cord protective measures with evoked potentials, cerebrospinal fluid drainage, and prevention of hypotension to minimize postoperative neurologic deficit. METHODS: Between November 2000 and July 2005, vital parameters and spinal cord function were monitored, including cerebrospinal fluid pressure and transcranial motor-evoked and somatosensory-evoked potentials in 36 stent-graft procedures (31 patients) on the thoracic or thoracoabdominal aorta. RESULTS: Stent-graft placement was technically successful in all patients. We achieved a survival rate of 100% without neurologic deficit after fast-track extubation. Eleven of 31 patients exhibited changes in evoked potentials during stent-graft deployment. In 12 of 31 patients (including the 11 with evoked potential alterations), cerebrospinal fluid pressure exceeded 15 mm Hg. Cerebrospinal fluid drainage and vital parameter adjustment were executed in those instances. We observed intraoperative evoked potential total recovery in 10 of 11 patients after these interventions. CONCLUSIONS: Interventions to improve spinal cord perfusion led to total recovery of spinal function in most patients (10/11). Therefore, spinal cord protective measures with motor- and somatosensory-evoked potential monitoring, cerebrospinal fluid drainage, and prevention of hypotension can reduce the incidence of spinal cord ischemia and improve the neurologic outcome of patients undergoing endovascular thoracic or thoracoabdominal aortic repair.

Mechanical reliability of the Jarvik 2000 Heart.

BACKGROUND: Device failure is a limitation of permanent mechanical circulatory support. We studied the mechanical reliability of the Jarvik 2000 Heart, an axial flow pump with ceramic bearings designed to provide more than 10 years' durability. METHODS: The Jarvik 2000 Heart was implanted in 102 patients between April 2000 and December 2004. Eighty-three pumps with an abdominal driveline were implanted as a bridge-to-transplantation, and 19 with postauricular power supply as lifetime therapy. Eighteen pumps were recovered intact after clinical use and run continuously on the bench to further assess durability. RESULTS: No implantable component failure occurred either in patients or during bench testing. The cumulative pump run-time was 110 years: 59 years overall in vivo and 51 years in vitro. The mean support time for bridge-to-transplant recipients was 159 days, and for discharged lifetime-therapy recipients 551 days. Six recipients were supported moer than 2 years, with the longest ongoing approaching 5 years. External cables caused three system failures, with a 95% freedom from system failure at 4 years. Device malfunctions, related to external cables (9) and lack of a backup battery (1), caused no adverse consequences. Before introduction of noncorrosive, gold-plated stainless steel connectors, corrosion was observed on three connectors to the retroauricular power supply. CONCLUSIONS: The Jarvik 2000 Heart has had no implantable component failure. Meaningful durability data and failure mode can only be established by real-time testing in patients. The reliability and dependability of this device, in addition to the exchangeability of external components, give promise for long-term circulatory support in critically ill heart failure patients.

Neurophysiological monitoring during thoracoabdominal aortic endovascular stent graft implantation.

OBJECTIVE: The aim of this study was to evaluate the benefit of neurophysiological monitoring during thoracic and thoracoabdominal endovascular stent graft implantation. METHODS: The spinal cords of 21 patients undergoing endovascular stent graft implantation on the thoracic and thoracoabdominal aorta were monitored with transcranial motor-evoked potentials (tcMEP) and somatosensory-evoked potentials (SSEP). All patients underwent mild systemic hypothermia (34-35 degrees C), constant cerebrospinal fluid (CSF) pressure and vital parameter monitoring. If CSF pressure exceeded 15 mmHg, CSF-drainage was carried out. RESULTS: Three of the 21 patients (14%) exhibited short-term loss of tcMEP and SSEP after the deployment of the self-expanding endoprosthesis. We observed an intraoperative recovery of the evoked potentials in all cases. CSF-drainage was necessary in three of them. One patient, whose potentials were stable intraoperatively, developed paraparesis 3 weeks after the intervention. CONCLUSIONS: Neurophysiological monitoring has proved to be an ideal monitoring method to detect spinal cord ischemia during thoracic and thoracoabdominal endovascular stent graft implantation. Due to the advantages of endovascular therapy (no aortic cross-clamping, continuous distal perfusion, and no reperfusion injury), changes in potentials were seldom observed.