IgG classification of anti-PF4/heparin antibodies to identify patients with heparin-induced thrombocytopenia during mechanical circulatory support.

Commercial immunoassays frequently detect anti-PF4/heparin antibodies during mechanical circulatory support (MCS), but only a small minority of patients develops heparin-induced thrombocytopenia (HIT). Whereas platelet functional tests can distinguish between platelet-activating and non-platelet-activating antibodies, commercial PF4-dependent immunoassays do not. Between 2003 and 2004, 113 patients were placed on MCS. Blood samples were obtained on postimplant day 5-7 for analyses by antibody assays and the functional heparin-induced platelet activation (HIPA) assay. Three distinct groups of patient sera were identified: platelet-activating anti-PF4/heparin antibodies (n = 10), non-platelet-activating anti-PF4/heparin antibodies (n = 53), and anti-PF4/heparin antibody negative (n = 50). Patients with platelet-activating antibodies had the highest risk for thromboembolic events (P < 0.005), whereas those with non-platelet-activating antibodies did not differ from antibody negative patients (P = 0.369). The enzyme-immunoassay and column agglutination assays, which cover all immunoglobulin classes, demonstrated adequate sensitivity and negative predictive value; yet, both lacked specificity with respect to the platelet-activating antibodies. If all antibody positive patients were further classified by an IgG-specific anti-PF4/heparin enzyme-immuno assay, specificity for platelet-activating antibodies increased. Whereas IgG-specific optical density (OD) values below 1.0 were likely for non-platelet-activating anti-PF4/heparin antibodies, higher values were progressively predictive for pathogenic platelet activation. The probability of the development of clinical HIT also increased steeply. In conclusion, platelet-activating anti-PF4/heparin antibodies are relatively common (about 9%) in patients on MCS and are associated with significantly higher thrombotic event rates. Low IgG-specific OD values (< 1.0) in the enzyme-immunoassay indicate low likelihood for the presence of platelet-activating antibodies. These results justify further validation so that anticoagulation during MCS becomes safer and adequate.

Implantation of CardioWest total artificial heart for irreversible acute myocardial infarction shock.

Patients who develop cardiogenic shock after acute myocardial infarction have a very high mortality rate despite early reperfusion therapy. Hemodynamic stabilization can often only be achieved by implanting a mechanical circulatory support system. When, in cases representing expansive myocardial impairment without any chance of recovery, pharmacological therapy and the use of percutaneous assist devices have failed, the implantation of a total artificial heart is indicated. We report our first experiences with this extensive and innovative method of managing irreversible cardiogenic shock patients. The CardioWest total artificial heart was implanted in 5 patients (male; mean age, 50 years). All patients were in irreversible cardiogenic shock despite maximum dosages of catecholamines, an intra-aortic balloon pump and/or a femoro-femoral bypass. In all patients early reperfusion therapy was performed. After implantation of the Cardio West system, all dysfunctional organ systems rapidly recovered in all patients. Four of 5 patients underwent successful heart transplantation after a mean support time of 156 days. One patient died because of enterocolic necroses caused by an embolic event after termination of dicumarol therapy. In summary, our first experiences justify this extensive management in young patients who would otherwise have died within a few hours.

Papillary fibroelastoma of the ascending aorta presenting with cardiogenic shock.

We describe an uncommon case of a 58-year-old woman who presented with cardiogenic shock. The echocardiography examination revealed a papillary fibroadenoma located in the ascending aorta which was subsequently surgically treated.

Extended donor criteria: use of cardiac allografts after carbon monoxide poisoning.

BACKGROUND: An increasing demand for cardiac allografts for the treatment of end-stage cardiac failure has led to a shift in the traditional views about donor criteria. The use of allografts exposed to high concentrations of carbon monoxide is still under discussion. The current literature on this topic is contradictory. We describe our experience with orthotopic cardiac transplantation, using cardiac allografts after carbon monoxide poisoning. METHODS: Between March 13, 1989 and August 1, 1996, 770 orthotopic heart transplantations were performed in our center. Within this period, we accepted five cardiac allografts from brain-dead, carbon monoxide-poisoned donors. Donor history showed carbon monoxide intoxication in all cases. At the time of organ explantation, donor hemodynamic parameters were feeble in all patients. RESULTS: The postoperative course was uneventful in three of the five recipients. The overall 3-year survival rate in this small group is 40%. Induction therapy or rescue therapy with mono/polyclonal antibodies was not necessary. Myocardial right-ventricular biopsies did not show any specific signs of carbon monoxide poisoning. CONCLUSIONS: In our opinion, cardiac allografts from donors exposed to carbon monoxide can be transplanted successfully in infants and adults, if there are no signs of severe hemodynamic dysfunction in the presence of a normal central venous pressure and low-dose support with catecholamines and there are no electrocardiographic changes in combination with elevated transaminase. With extended donor criteria, the hearts of carbon monoxide-poisoned victims could increase the number of suitable organs and lower the death rate of patients on the United Network for Organ Sharing and Eurotransplant International Foundation waiting lists.

Extended donor criteria: hemodynamic follow-up of heart transplant recipients receiving a cardiac allograft from donors > or = 60 years of age.

BACKGROUND: Heart transplantation (HT) has become a therapeutic option for patients suffering from endstage heart failure. The increasing demand for cardiac allografts has led to a shift toward extended donor criteria. In a retrospective analysis of 859 HT recipients, we report on the hemodynamic outcome of 19 HT patients who received cardiac allografts from donors > or =60 years of age. METHODS: From March 1989 to December 1997, we performed 883 orthotopic HT in 74 children and 809 adults at our transplant center. Within this period, 19 patients (17 women and 2 men) received cardiac allografts from donors > or =60 years of age. Recipient age ranged from 57 to 78 years (mean, 65+/-5 years). RESULTS: HT could be performed successfully in 19 cases. The early mortality rate was 16% (n=3). The late mortality rate was 37% (n=7). All long-term survivors are stable at New York Heart Association classification II (New York Heart Association Class II = resting hemodynamics: cardiac output normal; left ventricular end diastolic filling pressure elevated; clinically not compromised during mild to moderate workout). Although only 19 patients were retrospectively evaluated, there was a statistically significant (P<0.05) difference in survival among patients who received organs from male (11 vs. 8*) compared with female (8 vs. 2*) (*=death) donors. CONCLUSION: In our experience, it is possible to increase the cardiac donor pool by accepting allografts from donors, preferably female, > or =60 years of age in selected cases without a coronary angiogram, if hemodynamic parameters are in a normal range on mild-to-moderate inotropic support. We do not recommend cardiac allografts from donors > or =60 if there are signs of coronary insufficiency in the electrocardiogram, if left ventricle filling pressures are above normal on mild-to-moderate inotropic support and optimum hemodynamic management, or if there are signs of segmental dysfunction or mitral insufficiency >I in the echocardiogram.

Hemodynamic follow-up of cardiac allografts from poisoned donors.

BACKGROUND: The current shortage of donor organs, combined with an increasing demand for cardiac allografts, means that extended donor criteria are becoming more and more accepted. The use of cardiac allografts for transplantation from donors after acute poisoning is still under discussion; few data are currently available in the medical literature. We describe our experience with 19 orthotopic heart transplant recipients of organs from donors after acute intoxication with different agents. METHODS: Between March 1989 and December 1997, 883 orthotopic heart transplantations were performed at our transplant unit. Within this group, we accepted donor hearts after ethanol intoxication (n=1), benzodiazepine (n=1), alkylphosphate (E 605) in combination with beta-blocker intoxication (n=1), carbon monoxide poisoning (n=5), digitalis (n=1), digitalis/glibenclamide (n=1), chlormethiazole (n=1), propoxyphene (n=1), alkylphosphate (E 605) (n=1), insulin (n=2), neprobamate/ thiocyacide/flurazepam (n=1), paracetamol (n=1), carbamazepine (n=1), and cyanide (n=1) intoxication. At the time of organ explantation, hemodynamic data were available from all patients. RESULTS: Early mortality in this group was 11%; cumulative survival after 5 years was 74%. CONCLUSIONS: Based on our limited experience, cardiac allografts from donors exposed to different kinds of poisons can be transplanted in selected cases. If the donor organ is not hemodynamically compromised, showing regular filling pressures on low or mild inotropic support just before explantation, and if there are no electrocardiographic changes in combination with elevation of the transaminases, cardiac allograft transplantation seems to be a safe and life-saving procedure.

Novacor left ventricular assist system versus Heartmate vented electric left ventricular assist system as a long-term mechanical circulatory support device in bridging patients: a prospective study.

OBJECTIVE: Long-term mechanical circulatory support as a bridge-to-transplantation procedure and bridge to recovery is of increasing importance. The implantable left ventricular assist devices, Novacor N100 left ventricular assist system (Baxter Healthcare Corporation, Berkeley, Calif) and TCI HeartMate vented electric left ventricular assist system (Thermo Cardiosystems Inc, Woburn, Mass), have proved to be efficient devices in bridge-to-transplantation settings and for prolonged support. The two systems were compared with regard to reliability and morbidity. METHODS: Between October 1996 and March 1998, a prospective, single-center study was done that included 40 patients, 20 of whom were treated with the Novacor system and 20 of whom were treated with the HeartMate device. The diseases were mainly dilated cardiomyopathy (13/9) and ischemic cardiomyopathy (6/10). There were no statistically significant differences between the two groups regarding age, sex, preoperative clinical blood chemistry values, hemodynamic data, or risk factors. RESULTS: There were no statistically significant differences between the two groups with regard to postoperative hemodynamics, organ recovery, out-of-hospital support, and survival to heart transplantation. Mean duration of support was 235.3 +/- 210 days for the Novacor group and 174.6 +/- 175 days for the HeartMate group and mean out-of-hospital support was 241 +/- 179 days and 166 +/- 152 days for the two groups, respectively. Neurologic complications occurred significantly more often among the Novacor group, whereas the HeartMate group had a higher prevalence of infections and technical problems, which was statistically significant. Survival to transplantation was 65% for the Novacor group and 60% for the HeartMate group. CONCLUSIONS: Most patients had organ recovery with left ventricular assist system support, and a considerable number of patients in both groups underwent transplantation. However, both devices need revision to address the current problems, that is, thromboembolism for the Novacor device and infection and reliability for the HeartMate device.

Single-center experience with the thoratec ventricular assist device.

OBJECTIVE: The Thoratec ventricular assist device (Thoratec Laboratories, Pleasanton, Calif) is widely accepted for univentricular and biventricular support in patients with various indications. The aim of this study is to describe our experience with implantation of the Thoratec ventricular assist device in more than 100 patients. METHODS: From March 1992 to June 1998, 114 patients (98 men and 16 women; mean age, 47.9 years) received the Thoratec ventricular assist device for a mean duration of 44.9 days. The patients were divided into 3 groups. Group 1 included 84 patients in whom the system was applied as a bridge-to-transplant procedure. Group 2 included 17 patients with postcardiotomy cardiogenic shock, and group 3 included 13 patients with cardiogenic shock of other causes. RESULTS: Sixty-eight percent of patients in group 1 survived to transplantation with a posttransplant survival of 88%. The only independent risk factor affecting survival was age more than 60 years. Survivals in groups 2 and 3 were 47% and 31%, respectively. Main complications in all groups were bleeding, multiple organ failure, liver failure, sepsis, and neurologic disorders. CONCLUSIONS: The Thoratec ventricular assist device has proved to be a reliable device for bridge to transplantation and postcardiotomy support. Further studies are required on patient selection and on patient and device management to reduce the incidence of complications in these patient populations.

Predictors of survival in patients bridged to transplantation with the thoratec VAD device: a single-center retrospective study on more than 100 patients.

BACKGROUND: Careful patient selection markedly influences the outcome of patients who undergo mechanical circulatory support. Therefore, we tried to evaluate predictors of survival after implantation of the Thoratec ventricular assist device (VAD). METHODS: Between October 1992 and January 2000, 104 patients (86 men, 18 women, aged 11 to 69 years) received the Thoratec VAD as a bridge to transplant. A total of 51 patients required left ventricular support (LVAD), 50 patients required biventricular support (BVAD), and 3 patients required total artificial heart implantation. We performed univariate analysis of 25 parameters with regard to their effect on survival and then applied a multivariate analysis to evaluate those factors that turned out to be marginally significant. We performed all analysis for the total collective as well as for the LVAD and BVAD sub-group. RESULTS: The BVAD patients tended to have worse outcomes than did LVAD patients. We found no significant predictors of survival in either sub-group. In the total collective, however, we found the following pre-implant conditions were independent risk factors for survival after VAD implantation: patient age > 60 years (odds ratio [OR] 3.87, confidence interval [CI] 1.39 to 10.76), pre-implant ventilation (OR, 6.76; CI 2.42 to 18.84), and increased pre-implant total bilirubin (OR, 1.42; CL, 1.19 to 1.69). CONCLUSIONS: Transplant candidates on inotropic support should be considered for bridging to transplant as soon as bilirubin values start to increase or before respiratory function deteriorates and ventilation becomes necessary. In elderly patients, careful patient selection, particularly considering potential risk factors, might favorably affect their outcomes.

The time course of natriuretic hormones as plasma markers of myocardial recovery in heart transplant candidates during ventricular assist device support reveals differences among device types.

BACKGROUND: The natriuretic hormones ANP and BNP are expressed differently in the myocardium. Both hormones have compensatory diuretic activity during heart failure. Mechanical stretch of the myocardial walls induces the expression of these hormones. In failing human myocardium, both ANP and BNP are transcribed in the ventricular myocardium in high amounts. We measured the plasma concentrations of ANP and BNP in patients supported by various ventricular assist devices (VADs) at various times. We analyzed the time courses of ANP and BNP to determine (1) the time scale of their down-regulation as a marker of putative myocardial recovery, (2) their steady-state levels under VAD support and (3) differences caused by various VAD devices. METHODS: We analyzed ANP and BNP using commercially available radioimmune assays. We analyzed the time courses of patients supported by Thoratec (THO) LVAD (n = 8), TCI Heartmate (TCI) (n = 6), Novacor (NOV) (n = 7), and Lionheart (LIO) (n = 3). RESULTS: Patients supported with NOV and some patients with TCI showed down-regulation of BNP to a steady-state level at 30 to 50 days, following a single exponential decay. In contrast, patients supported by THO or LIO did not reveal a determined time course of the natriuretic hormones. Only a few patients reached normal plasma values during VAD support. CONCLUSION: The time courses of ANP and BNP differ among VAD types because of construction and/or driving mode, which might be important when considering patients for weaning from VAD without heart transplant.

Midterm follow-up of patients discharged from hospital under left ventricular assistance.

BACKGROUND: Against the background of increasing demand for long-term mechanical circulatory support, discharging patients to their homes while on assist devices becomes more and more important. This report describes the midterm follow-up of 66 patients who were allowed to leave the hospital under left ventricular assist device (LVAD) support with Novacor or HeartMate systems. Between May 1994 and January 2000, 66 patients (9 women, 57 men, between 15 and 68 years old) under LVAD support fulfilled our criteria for being discharged home on the device. Intent to treat comprised bridging to transplantation in 59 patients, bridging to recovery in 5 patients, and alternative to transplantation in 2 patients. Forty-four patients received support with Novacor, 18 patients with the VE HeartMate, 2 patients with centrifugal pumps and Novacor, and 1 patient each with Novacor and Thoratec/Medos HIA-VAD. The mean out-of-hospital (OOH) follow-up period was 162 +/- 187 days, with a cumulative OOH experience of 30 patient years. Twenty-nine patients were not readmitted, and 37 patients were readmitted 54 times (23 patients were readmitted once, 11 patients twice, and 3 patients 3 times). The primary reasons for readmission included neurologic disorders and infection complications. At 229 days, 50% of all patients were free from readmission. The readmission rate was 1.8 patient/year. Sixteen patients died while on LVAD support (24%). Our midterm follow-up results show the safety and efficacy of this therapeutic option. Acceptable hospital readmission rates strongly support the future use of this technology as an alternative to transplantation in managing end-stage heart failure patients.

Outcome of heart transplantation in patients previously infected with hepatitis C virus.

The lack of knowledge about the course of hepatitis C virus infection (HCV) before heart transplantation (HTx) prompted us to describe our experience with 4 such patients who presented with positive HCV serology before surgery. Two experienced non-liver related deaths at 3.5 and 5 years after HTx, and none of the patients developed signs of hepatic insufficiency during the follow-up (mean 3.8 years). Tests for HCV antibodies were frequently negative, whereas viral RNA was detected in 81% of the measurements, showing that virus detection techniques seem to be more sensitive than serology techniques in detecting HCV infection in this group of patients. Although immunosuppression promotes active HCV replication, it does not seem to change the chronic features of HCV infection during the first years in patients with good liver function.

New technique for the outflow cannulation of right ventricular assist device.

Cannulating the outflow cannula of a right ventricular assist device (RVAD) through the main pulmonary artery is often troublesome because of extensive dissecting adhesion. We implanted RVADs using the new technique for outflow cannulating through the right pulmonary artery between the ascending aorta and the superior vena cava. With this technique, we needed only a little dissection and no cardiopulmonary bypass. This technique could make RVAD implantation simple, quick, and safe.

Temporary pulsatile ventricular assist devices and biventricular assist devices.

BACKGROUND: During the past years several systems for mechanical circulatory support have become available. In this study we describe our experience with short-term and mid-term application of the ABIOMED and Thoratec device. METHODS: Since 1990 the ABIOMED BVS and since 1992 the Thoratec VAD have been applied to 75 and 103 patients, respectively, with postcardiotomy heart failure, as a bridge-to-transplant procedure, and with different other indications. RESULTS: In the ABIOMED collective 25 of 50 patients (50%) with postcardiotomy heart failure and 1 of 4 patients with miscellaneous other indications could be discharged from hospital, 7 of 14 bridge-to-transplant patients (50%) underwent transplantation with a posttransplant survival of 86%. In the Thoratec collective 6 of 10 patients (60%) with postcardiotomy heart failure and 4 of 8 patients (50%) with miscellaneous indications could be discharged from hospital, 48 bridge-to-transplant patients (74%) underwent transplantation with a posttransplant survival of 90%. CONCLUSIONS: The results show the versatility of the Thoratec VAD for short-term and mid-term application in patients with postcardiotomy heart failure and as a bridge-to-transplant procedure. The use of the ABIOMED device is not indicated for bridging patients to transplantation. Although in case of postcardiotomy heart failure, Thoratec is also superior to ABIOMED, the high costs of the Thoratec VAD limits its wide acceptance in this patient cohort.

A novel method to reduce device-related infections in patients supported with the HeartMate device.

Improved implantable left ventricular assist device technology has made survival to heart transplantation a near certainty. Nevertheless, infection remains a major risk to recipients of current percutaneous systems. We developed a modified implantation technique applied to the last 9 of 30 patients who received the HeartMate vented electric left ventricular assist system (LVAS). Covering the upper surface of the pump with a patch of knitted graft material was followed by a decline in the incidence of pocket infections from 33.3% to 11.1%. This modification compares favorably to that of a lengthened percutaneous driveline tunnel in reducing device-related infection.

Mechanical circulatory support with the Thoratec assist device in patients with postcardiotomy cardiogenic shock.

BACKGROUND: In spite of modern cardiac surgical techniques, severe cardiogenic shock not responding to pharmacologic therapy and intraaortic balloon pumping develops in about 0.2% to 1.2% of patients undergoing cardiac operations. METHODS: From September 1987 to September 1994, 184 patients were supported with different mechanical circulatory support systems. Nine patients with postcardiotomy cardiogenic shock were supported with the Thoratec ventricular assist device. Four patients suffered early postcardiotomy cardiogenic shock, and 5 patients suffered late postcardiotomy cardiogenic shock. In 6 patients the Thoratec device was applied exclusively, in 2 patients both Bio-Medicus and Thoratec, and in 1 patient both ABIOMED and Thoratec devices were used. Duration of support ranged from 5 to 46 days with a mean duration of 15 days. RESULTS: Four patients (44%) survived and were discharged. Main complications and causes of death were multiple organ failure and sepsis. CONCLUSIONS: The results justify the use of Thoratec assist device in patients with severe preoperative cardiogenic shock.

Successful implantation of Thoratec assist device: wrapping of outflow conduit in Hemashield graft.

Persistent oozing and bleeding through the wall of the built-in outflow conduit in mechanical circulatory assist devices is a troublesome problem. Wrapping the outflow conduit of Thoratec in a Hemashield graft without preclotting completely prevents oozing and bleeding.

Device and patient management in a bridge-to-transplant setting.

BACKGROUND: A variety of sophisticated devices have been developed for mechanical circulatory support in patients bridged to cardiac transplantation. Based on 13 years' experience, we have developed specific protocols for patient selection and management for different devices. METHODS: The principal systems applied in the bridge-to-transplant cohort are the Thoratec ventricular assist device (n = 144, mean duration of support 53 +/- 57 days), the Novacor left ventricular assist system (LVAS) (n = 85, mean duration of support 154 +/- 15 days), and the HeartMate LVAS (n = 54, mean duration of support 143 +/- 142 days). The Thoratec device is used for biventricular assistance or if the duration of support is expected to be less than 6 months. For long-term support, either the Novacor or HeartMate LVAS are preferred. RESULTS: Despite careful postoperative patient management, this group of patients is prone to a variety of complications. Bleeding occurred in 22% to 35%, right heart failure in 15% to 26%, neurologic disorders in 7% to 28%, infection in 7% to 30%, and liver failure in 11% to 20% of patients. Complications varied with the device applied and the patient's preoperative condition. A total of 73 patients were discharged from hospital for a mean period of 184 days; this cumulative experience amounted to 37.5 patient-years. CONCLUSIONS: The Novacor and the HeartMate systems offer the additional possibility of discharging patients during support if they fulfill certain criteria. The main reasons for rehospitalization were thromboembolic and infectious complications.

Mechanical circulatory support: the Bad Oeynhausen experience.

From September 1987 to February 1994, we treated 147 patients ranging between 11 and 82 years old with different mechanical circulatory support systems. The applied devices were the Bio-Medicus centrifugal pump in 61 patients, the Abiomed BVS System 5000 in 49 patients, the Thoratec ventricular assist device in 42 patients, and the Novacor left ventricular assist device in 7 patients. On the basis of indication for mechanical circulatory support, the patients were divided into three groups: group 1 consisted of 72 patients with postcardiotomy cardiogenic shock; group 2, 50 patients in whom mechanical support was used as a bridge to cardiac transplantation; and group 3 (miscellaneous), 25 patients in cardiogenic shock resulting from acute myocardial infarction (n = 14), acute fulminant myocarditis (n = 3), primary graft failure (n = 2), right heart failure after heart transplantation (n = 3), and acute rejection (n = 3). Time of support ranged from 1 hour to 97 days (mean duration, 10.8 days). Seventy-five patients (51%) were discharged from the hospital. The best survival rate was achieved in group 2 with 72%, followed by group 1 with 44% and then group 3 with 28%. The most frequent complications in group 1 were bleeding (44%), multiple-organ failure (24%), neurologic disorders (18%), and acute renal failure (15%). In group 2, the major complications were bleeding (34%) and cerebrovascular disorders (22%) and in group 3, multiple-organ failure and sepsis (60%) and bleeding (32%).

Pre-existing elevated pulmonary vascular resistance: long-term hemodynamic follow-up and outcome of recipients after orthotopic heart transplantation.

BACKGROUND: Elevation of pulmonary vascular resistance (PVR) has been considered to predict a bad outcome after orthotopic heart transplantation (HTx). A transpulmonary gradient (TG) > or =15 mmHg and PVR > or =5 wood (w) are correlated with a three-fold increase in 2-days as well as 30-days and 6-, 12-month mortality. METHODS: We performed a retrospective analysis of 400 consecutive transplanted patients (pts) on hemodynamic data over a time period of 3.5 years. In 83 pts (23%) preoperative PVR was > or =5 w and TG >15 mmHg. Vasodilator studies were performed in this group of pts in order to evaluate pulmonary vasoreactivity or hemodynamic improvement. RESULTS: Hemodynamic follow-up post-transplantation showed a significant (p<0.001) decrease in mean TG to 8.8 mmHg within the first, 7.7 after the fifth year as well as decrease in PVR from 5.5 to 1.6, within the first and fifth year post-transplantation. Compared to the control group (n=286) (re-transplants n=6 and pediatric pts n=25 excluded) pts with TG <15 mmHg and/or PVR <5 w, transplanted within the same period, 30-day mortality and cumulative survival after 1 and 5 years do not show any significant difference with a mortality of 3%, 22% and 33% (p<0.05). Subgroup analysis for pts with endstage of ischemic versus dilatative cardiomyopathy has not shown any significant difference in mortality. CONCLUSIONS: In a retrospective analysis of 400 pts elevated PVR does not predict a bad outcome after orthotopic heart transplantation in early and late mortality.