Kåre Sander

Severely impaired von Willebrand factor-dependent platelet aggregation in patients with a continuous-flow left ventricular assist device (HeartMate II).

OBJECTIVESnThis study investigated the influence of the mechanical blood pump HeartMate II (HMII) (Thoratec Corporation, Pleasanton, California) on blood coagulation and platelet function.nnnBACKGROUNDnHMII is an implantable left ventricular assist device used for the treatment of heart failure. Patients treated with HMII have increased bleeding tendencies.nnnMETHODSnWe measured agonist-induced platelet aggregation in 16 patients on HMII support.nnnRESULTSnThe von Willebrand factor (vWF)-dependent ristocetin-induced platelet aggregation was impaired in 11 of the 16 patients, of which 12 had experienced at least 1 minor or major bleeding episode. The impaired ristocetin-induced platelet aggregation was associated both with decreased specific activity of plasma vWF, presumably due to lack of high molecular weight vWF multimers, as well as with attenuated function of the platelets themselves.nnnCONCLUSIONSnThe results imply that HMII treatment is associated with impaired platelet aggregation, which may contribute to an increased tendency to bleed.

Incidence of ventricular arrhythmias in patients on long-term support with a continuous-flow assist device (HeartMate II).

The incidence of ventricular tachycardia (VT) or ventricular fibrillation (VF) in patients supported with a continuous-flow left ventricular assist device (LVAD) has not been investigated in detail. In 23 consecutive recipients of a HeartMate II, we analyzed the incidence of VT/VF during a total of 266 months of follow-up. Sustained VT or VF occurred in 52% of the patients, with the majority of arrhythmias occurring in the first 4 weeks after LVAD implantation. VT/VF requiring implantable cardioverter-defibrillator (ICD) shock or external defibrillation occurred in 8 patients and significant hemodynamic instability ensued in 3 patients. There were no clear predictors of VT/VF, and it is argued that prophylactic ICD implantation should be considered in patients supported with a continuous-flow LVAD.

Central and Peripheral Blood Flow During Exercise With a Continuous-Flow Left Ventricular Assist DeviceClinical Perspective

Background— End-stage heart failure is associated with impaired cardiac output (CO) and organ blood flow. We determined whether CO and peripheral perfusion are maintained during exercise in patients with an axial-flow left ventricular assist device (LVAD) and whether an increase in LVAD pump speed with work rate would increase organ blood flow. Methods and Results— Invasively determined CO and leg blood flow and Doppler-determined cerebral perfusion were measured during 2 incremental cycle exercise tests on the same day in 8 patients provided with a HeartMate II LVAD. In random order, patients exercised both with a constant (≈9775 rpm) and with an increasing pump speed (+400 rpm per exercise stage). At 60 W, the elevation in CO was more pronounced with increased pump speed (8.7±0.6 versus 8.1±1.1 L · min−1; mean±SD; P=0.05), but at maximal exercise increases in CO (from 7.0±0.9 to 13.6±2.5 L · min−1; P<0.01) and leg blood flow [0.7 (0.5 to 0.8) to 4.4 (3.9 to 4.8) L · min−1 per leg; median (range); P<0.001] were similar with both pumping modes. Normally, middle cerebral artery mean flow velocity increases from ≈50 to ≈65 cm · s−1 during exercise, but in LVAD patients with a constant pump speed it was low at rest (39±14 cm · s−1) and remained unchanged during exercise, whereas in patients with increasing pump speed, it increased by 5.2±2.8 cm · s−1 at 60 W (P<0.01). Conclusions— With maximal exercise, the axial-flow LVAD supports near-normal increments in cardiac output and leg perfusion, but cerebral perfusion is poor. Increased pump speed augments cerebral perfusion during exercise.

Decreased mitochondrial oxidative phosphorylation capacity in the human heart with left ventricular systolic dysfunction

Heart failure (HF) with left ventricular systolic dysfunction (LVSD) is associated with a shift in substrate utilization and a compromised energetic state. Whether these changes are connected with mitochondrial dysfunction is not known. We hypothesized that the cardiac phenotype in LVSD could be caused by reduced mitochondrial oxidative phosphorylation (OXPHOS) capacity and reduced mitochondrial creatine kinase (miCK) capacity. The study aim was to test mitochondrial OXPHOS capacity in LVSD myocardium compared with OXPHOS capacity in a comparable patient group without LVSD.

Central and Peripheral Blood Flow During Exercise With a Continuous-Flow Left Ventricular Assist Device Constant Versus Increasing Pump Speed: A Pilot Study

Background— End-stage heart failure is associated with impaired cardiac output (CO) and organ blood flow. We determined whether CO and peripheral perfusion are maintained during exercise in patients with an axial-flow left ventricular assist device (LVAD) and whether an increase in LVAD pump speed with work rate would increase organ blood flow. Methods and Results— Invasively determined CO and leg blood flow and Doppler-determined cerebral perfusion were measured during 2 incremental cycle exercise tests on the same day in 8 patients provided with a HeartMate II LVAD. In random order, patients exercised both with a constant (≈9775 rpm) and with an increasing pump speed (+400 rpm per exercise stage). At 60 W, the elevation in CO was more pronounced with increased pump speed (8.7±0.6 versus 8.1±1.1 L · min−1; mean±SD; P=0.05), but at maximal exercise increases in CO (from 7.0±0.9 to 13.6±2.5 L · min−1; P<0.01) and leg blood flow [0.7 (0.5 to 0.8) to 4.4 (3.9 to 4.8) L · min−1 per leg; median (range); P<0.001] were similar with both pumping modes. Normally, middle cerebral artery mean flow velocity increases from ≈50 to ≈65 cm · s−1 during exercise, but in LVAD patients with a constant pump speed it was low at rest (39±14 cm · s−1) and remained unchanged during exercise, whereas in patients with increasing pump speed, it increased by 5.2±2.8 cm · s−1 at 60 W (P<0.01). Conclusions— With maximal exercise, the axial-flow LVAD supports near-normal increments in cardiac output and leg perfusion, but cerebral perfusion is poor. Increased pump speed augments cerebral perfusion during exercise.

Primary cardiac tumors: a clinicopathologic evaluation of four cases

INTRODUCTIONnWe report the clinical, pathological, and immunohistochemical features of four primary malignant cardiac tumors identified at the Department of Pathology, Rigshospitalet, Denmark. A panel of immunohistochemical markers for classification is proposed.nnnMETHODSnBetween 2000 and 2008, four patients with malignant cardiac tumors were treated at our hospital. We retrospectively reviewed the medical records and evaluated the patient characteristics and treatment.nnnRESULTSnThree patients presented with severe dyspnea; one patient presented with chest pain. Transthoracic echocardiography demonstrated, in all four cases, abnormal masses in the atria. The cases were, based on morphological features and immunoprofile, classified as myogenic sarcoma (two cases), undifferentiated pleomorphic sarcoma, and leiomyosarcoma. Three of the patients received orthotopic heart transplantation. One patient survived 6.5 years after the diagnosis, and two patients are still alive 2 and 3 years after being diagnosed, respectively.nnnCONCLUSIONSnAll four cases were sarcomas. A limited number of immunohistochemical markers can be used in order to define a specific line of differentiation. In this small study, three of the patients were offered orthotopic heart transplantation, and the survival times were generally longer than in most series.

Left Ventricular Assist Device as Bridge to Recovery for Anthracycline‐Induced Terminal Heart Failure

Anthracycline treatments are hampered by dose-related cardiotoxicity, frequently leading to heart failure (HF) with a very poor prognosis. The authors report a case of a 19-year-old man developing HF after anthracycline treatment for Ewing sarcoma. Despite medical treatment, his condition deteriorated to terminal HF, leading to implantation of a mechanical left ventricular assist device (LVAD). His heart function recovered, allowing explantation of the device 14 months after implantation. Heart transplantation is often contraindicated in the first years after treatment for cancers, and LVAD as bridge to recovery may be warranted in similar patients.

Rapid Decline in Glomerular Filtration Rate during the First Weeks Following Heart Transplantation

We hypothesized that a decrease in renal function is seen immediately after heart transplantation (HTX) with little recovery over time. Twelve consecutive patients had their glomerular filtration rate (GFR) measured using (51)Cr-ethylenediaminetetraacetic acid (EDTA) measured GFR (mGFR) before transplantation and at 1, 2, 3, and 26 weeks after transplantation. The mGFR decreased by 28% and 24% during the first 3 and 26 weeks, respectively, with mean blood cyclosporine concentration as an independent risk factor for the decrease in mGFR. The identification of cyclosporine A (CsA) as the most important risk factor for the rapid and sustained decrease in renal function supports the need for more studies on renoprotective strategies immediately after HTX.

Central and Peripheral Blood Flow During Exercise With a Continuous-Flow Left Ventricular Assist DeviceClinical Perspective: Constant Versus Increasing Pump Speed: A Pilot Study

Background— End-stage heart failure is associated with impaired cardiac output (CO) and organ blood flow. We determined whether CO and peripheral perfusion are maintained during exercise in patients with an axial-flow left ventricular assist device (LVAD) and whether an increase in LVAD pump speed with work rate would increase organ blood flow. Methods and Results— Invasively determined CO and leg blood flow and Doppler-determined cerebral perfusion were measured during 2 incremental cycle exercise tests on the same day in 8 patients provided with a HeartMate II LVAD. In random order, patients exercised both with a constant (≈9775 rpm) and with an increasing pump speed (+400 rpm per exercise stage). At 60 W, the elevation in CO was more pronounced with increased pump speed (8.7±0.6 versus 8.1±1.1 L · min−1; mean±SD; P=0.05), but at maximal exercise increases in CO (from 7.0±0.9 to 13.6±2.5 L · min−1; P<0.01) and leg blood flow [0.7 (0.5 to 0.8) to 4.4 (3.9 to 4.8) L · min−1 per leg; median (range); P<0.001] were similar with both pumping modes. Normally, middle cerebral artery mean flow velocity increases from ≈50 to ≈65 cm · s−1 during exercise, but in LVAD patients with a constant pump speed it was low at rest (39±14 cm · s−1) and remained unchanged during exercise, whereas in patients with increasing pump speed, it increased by 5.2±2.8 cm · s−1 at 60 W (P<0.01). Conclusions— With maximal exercise, the axial-flow LVAD supports near-normal increments in cardiac output and leg perfusion, but cerebral perfusion is poor. Increased pump speed augments cerebral perfusion during exercise.