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.

Viremia and excretion of TT virus in immunosuppressed heart transplant recipients and in immunocompetent individuals

BACKGROUND

The TT virus (TTV) was discovered in patients with symptomatic posttransfusion hepatitis, but many viremic individuals are asymptomatic. Inadvertent transfusion-associated transmission must therefore be anticipated. We screened blood donors and heart transplant recipients for TTV infections.

METHODS

Nested polymerase chain reaction was used to detect TTV DNA in plasma, serum, urine, and fecal samples from 600 blood donors, from 100 healthy individuals, and from 495 heart transplant recipients.

RESULTS

A total of 3.2% of the blood donors, but 25% of the heart transplant recipients were viremic. TTV subtypes G1a/b and G2a/b were observed in both groups, but the subtype distributions were discrepant. A severe, acute infection with TTV subtype 3 was observed in one blood donor. The prevalence of TTV infections in heart transplant recipients was not correlated to transfusion frequency. Nine viremic heart transplant recipients and their 75 blood donors were studied in detail. Seven blood donors were viremic, but only two "pairs" of viremic blood donors and transfusion recipients had identical TTV isolates. TTV DNA was detected in the feces of 5% (5/100) of immunocompetent individuals (staff), in 46% (52/112) of viremic heart transplant recipients, and in the urine of 55% (20/36). TTV DNA was detected in six of six batches of pooled "virus-inactivated" plasma (solvent/detergent treated), and in none of eight batches of commercial immunoglobulins.

CONCLUSION

Although TTV is transfusion-transmissible, the parenteral transmission rate may have been overestimated. Many TTV infections are apparently acquired by nonparenteral routes. Immunoglobulins are safe but pooled plasma is not safe regarding TTV transmission.

Cardiopulmonary resuscitation after cardiac surgery: a two-year study

OBJECTIVE

The aim of this study was to investigate the incidence of cardiopulmonary resuscitation (CPR) after cardiac surgery and to find predictors of survival.

DESIGN

A retrospective study with data obtained by chart review.

SETTING

A university hospital 24-bed cardiac surgical intensive care unit (ICU).

PARTICIPANTS

Between 1993 and 1994, 4,968 consecutive adult patients who underwent cardiac surgery at the authors' hospital were studied.

INTERVENTIONS

None.

MAIN RESULTS

One hundred thirteen of these patients (2.3%) were resuscitated. Seventy-nine patients (70%) survived to be discharged from the hospital. Significant predictors of survival were the time between admission to the ICU and initiation of CPR, CPR time, and creatine kinase (CK) and CK-MB values.

CONCLUSIONS

The incidence of CPR after cardiac surgery was 2.3% with no difference between valve surgery and CABG. Best results were achieved when arrhythmias or bleeding were the predisposing causes. Further studies have to be undertaken concerning long-term results and quality of life of the discharged patients.

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.

Long-term mechanical circulatory support

Against the background of an increasing number of patients waiting for heart transplantation but a stagnating number of transplant procedures, long-term mechanical circulatory support is gaining major importance. We investigated the outcome of 20 patients (15 men, and 5 women, aged between 15 and 66 years) each supported for more than 100 days between September 1987 and August 1996. The indications for implantation were bridging in 17 patients, myocarditis in 2 patients, and postcardiotomy cardiogenic shock in one patient. 12 patients received the Novacor IVAD, 4 patients the Thoratec system, 3 patients the HeartMate device and one patient both Novacor and Thoratec. Mean duration of support was 178.1 days, 15 patients were transplanted, 14 of them could be discharged, 2 patients died, 4 patients are still waiting. The most frequent complication was device-related infection in 11 patients. The results have shown that all three systems are safe and reliable devices for supporting patients for more than 100 days.

Tuberculosis in heart transplant recipients

STUDY OBJECTIVES

To clarify the prevalence and factors associated with tuberculosis, as well as patient survival in heart transplant recipients.

DESIGN

A retrospective review of case records of all heart transplant recipients from March 1989 to February 1996 during a 7-year period.

SETTING AND PATIENTS

During the period reviewed, 727 orthotopic heart transplantations were performed in 716 patients at the Heart Center Northrhine-Westphalia, Germany.

RESULTS

Tuberculosis was proved in seven (1%) patients (four men/three women; age, 33 to 71 years; two miliary lesions, three pulmonary lesions, and two urogenital lesions). None of them had primary history of tuberculosis. Tuberculin skin tests were not performed before transplantation because there were no lesions indicating primary infection of turberculosis. The immunosuppressive regimen was based on double-drug (cyclosporine + azathioprine) therapy. Immunosuppression had been intensified by methylprednisolone pulses at least three times in those seven patients, and prednisone had been used orally in six of seven patients. Tuberculosis developed from 2.5 to 41 months after transplantation. Tuberculosis was found by routine examinations in four of seven patients. Diagnoses were made with both direct microscopy and cultures in six patients, and by histologic study in one. Treatment consisted of isoniazid, rifampicin, ethambutol, and pyrazinamide. Two patients with miliary lesions were treated with four drugs, and the others were treated with three drugs. Isoniazid was used in all patients. Rifampicin, which decreases cyclosporine serum levels, was not used from the beginning in one patient and treatment with it was stopped halfway in another patient because low cyclosporine level had induced rejection. Six of the seven patients are doing well while receiving antituberculous therapy. One patient died with miliary tuberculosis as a cause of death.

CONCLUSIONS

The prevalence of tuberculosis in heart transplant recipients was higher than that in the general population. We recommend that a high degree of clinical suspicion is maintained for tuberculosis in heart transplant recipients with meticulous follow-up, and that the treatment of tuberculosis has to be with meticulous care, especially during the use of rifampicin.

Mechanical circulatory support: lessons from a single centre

Over recent years, a number of different mechanical circulatory support (MCS) products have been developed to a stage where they are no longer investigational devices. Registry data provide some information, but this is limited by the mix of historical and contemporary data and the voluntary nature of the contributions. As yet, there are no clear guidelines for patient selection, the differential application of generically different devices or for optimal patient management. Ours is a busy centre offering a comprehensive cardiovascular service. This review details our experience since 1987 and 189 patients supported with five different types of device, used in all of the common applications. Our experience has permitted the formulation of some general principles and guidelines. Data published by registries and by individual manufacturers are, as yet, not standardized. We hope that our experience will be of interest to those centres wishing to establish a mechanical assist service.

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.

Seven years of experience with the centrifugal pump in patients with cardiogenic shock

From September 1987 to September 1994 61 patients between 29 and 78 years of age received mechanical circulatory support by means of the Biomedicus centrifugal pump. The patients were divided into three groups by indication: Group I included 15 patients with early postcardiotomy cardiogenic shock and 24 patients with late postcardiotomy cardiogenic shock. Group II 11 patients with therapy-resistant cardiogenic shock following acute myocardial infarction, and Group III 11 patients with cardiogenic shock of other etiologies. Duration of support was 1 to 347 hours. Survival rates were 46.7% and 33.3% in patients with early and late postcardiotomy cardiogenic shock, respectively (Group I), 27.2% in Group II, and 18.1% in Group III. Most frequent complications were bleeding (40%, 58%) and acute renal failure (26.7%, 29.2%) in Group I and multiple organ failure in Groups II and III (64% and 45.5%). Major causes of death were bleeding and multiple organ failure in Group I (37.5%) and multiple organ failure in Groups II and III (87.5% and 50%). Groups II and III (87.5% and 50%).

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%).

Mechanical ventricular support using pulsatile Abiomed BVS 5000 and centrifugal Biomedicus-pump in postcardiotomy shock

Since we started using ventricular assist devices (VAD) in July 1987 up to August 1993, 63 of 15,650 (0.4%) patients (pts) who underwent open heart surgery were supported postoperatively by VAD at out institution. Forty-three were male and 20 female, mean age 55.5 years. In 49 pts coronary artery bypass grafting (CABG), in 8 pts valve surgery, in 3 pts combined CABG and valve surgery and in 3 pts corrective procedures for congenital heart disease were performed. Perioperative myocardial infarction was the most frequent indication (73%). In 37 of the 63 pts (58.7%) a centrifugal (Biomedicus pump (group A) was used and in 26 pts (41.3%) a pulsatile Abiomed BVS 5000 (group B). Fourteen of 37 pts (38%) in group A were weaned from the VAD and all of them were discharged. Twenty-three pts were unable to be weaned and 19 of these pts died. The remaining 4 pts were transplanted successfully and subsequently 3 died and 1 was discharged. In all, 15 pts (39%) were long-term survivors. Sixteen of 26 pts (62%) in group B were weaned from VAD and 13 (50%) of them were discharged of whom 3 died. Ten patients were unable to be weaned and 7 of these died. The remaining 3 pts were transplanted successfully. In all, 16 pts (61.5%) were long-term survivors. The shorter the interval between beginning resuscitation and application of VAD the better the outcome. Younger age, VAD installation in OR, support time between 2 and 7 days and Abiomed pump, influence the survival rate positively.(ABSTRACT TRUNCATED AT 250 WORDS)

Emotional adjustment and perceived locus of control in heart transplant patients

Orthotopic heart transplantation has been established as a routine clinical operation. In this study, we were interested in: (a) how patients cope emotionally with the situation pre- and postsurgically, especially with regard to anxiety and depression; and (b) whether the patient's perceived locus of control is related to emotional adjustment before and after heart transplantation. Twenty patients who were on the waiting list for heart transplantation with highest priority provided complete psychological questionnaires presurgically and 20 days after surgery when intensive care was no longer required. During the waiting period, patients rated high on depression, state and trait anxiety in comparison with healthy references while ratings on perceived locus of control scales were within the norm ranges. After surgery, heart transplant patients experienced significantly less state/trait anxiety and depression reaching levels which were no longer statistically different from health references. While postsurgical ratings of anxiety (state and trait) and depression were not significantly correlated with presurgical ratings, both were closely related to ratings of locus of control. Belief in powerful others was positively correlated with pre- and postsurgical anxiety and depression. Chance control orientation was related only to presurgical emotional disturbances. It can be concluded that emotional adjustment after heart transplantation is more likely to be predicted by presurgical ratings of locus of control than by presurgical emotional adjustment.

Improvement of survival rate in patients with cardiogenic shock by using nonpulsatile and pulsatile ventricular assist device

Between January 1988 and January 1992, 65 patients (pts) had a ventricle assist device (VAD) inserted in our clinic. In 24 pts a VAD was applied because of primarily unsuccessful weaning from cardiopulmonary bypass (Group A). In a further 24 pts (Group B) a VAD was installed for the therapy of refractive cardiogenic shock (CS) after initially successful cardiac surgery (n = 21) and after acute myocardial infarction (n = 3). Twelve pts were bridged to heart transplantation (Group C) and five had a VAD inserted for various other reasons (Group D). In 36 (55.4%) of the total 65 pts a nonpulsatile VAD (Biomedicus 540) was used: 10 in Group A; 20 in B, 3 in C and 3 in D. In 29 pts (44.6%) a pulsatile VAD (Abiomed BVS 5000) was used: 14 in Group A, 4 in B, 9 in C and 2 in D. Weaning rate and long-term survival rates were 50% and 46% respectively in Group A and 38% and 42% in Group B. Seven pts from Group C were transplanted and six are long-term survivors. Two pts (40%) in Group D were discharged from hospital. Major postoperative complications were bleeding (46%), thromboembolism (14%), multiple organ failure (11%), renal failure (11%), arterial embolism (4.6%), sepsis (3%). The results indicate that application of a VAD can be recommended in pts with postcardiotomy CS to allow recovery of cardiac function and in pts with irreversible ventricular damage as bridging to HTX.

Immunoglobulin preparations from hepatitis C antibody-positive plasma donors: influence on diagnosis and risk of infection in heart transplant recipients

All heart transplant patients in our clinic received intravenous immunoglobulins as a prophylaxis against cytomegalovirus infections or reactivations. Serum was sampled from 160 heart transplant patients within 4 months after surgery. In 98 samples (61%) hepatitis C virus (HCV)-specific antibodies could be detected by a "second generation" enzyme immunoassay. Of these HCV antibody-positive patients 89 were tested for a second time. At this time, 5-11 months later, in 66 patients (74%) the HCV antibody had disappeared. In the 23 still positively reacting patients, immunoglobulins were given in the last 6 months before serum sampling. Nine commercial immunoglobulin preparations were tested for HCV-specific antibodies and the presence of HCV RNA. Seven preparations were anti-HCV positive with titres in the range of 64-256, whereas reverse transcription and polymerase chain reaction did not detect HCV RNA in any immunoglobulin preparation. Passive antibody transfer rather than a HCV infection is the cause of HCV antibody detection in our patients. The presence of HCV antibodies in high concentrations in commercial immunoglobulin preparations may only be explained by an extremely high proportion of anti-HCV-positive single donations in the plasma pools used for immunoglobulin production. The passive HCV antibody transmission prevents anti-HCV serological monitoring of patients treated with these preparations. Additionally, there are reports on the transmission of hepatitis non-A, non-B via immunoglobulin preparations. Therefore, we recommend an anti-HCV screening of plasma donors.

Effects of pulsatile perfusion on plasma catecholamine levels and hemodynamics during and after cardiac operations with cardiopulmonary bypass

Thirty patients scheduled for elective coronary artery bypass grafting were studied in two groups. Group A had standard cardiopulmonary bypass with nonpulsatile perfusion and group B had pulsatile perfusion. Measurements of plasma epinephrine, norepinephrine, granulocyte elastase, and hemodynamic parameters including mean arterial pressure total peripheral resistance, cardiac index, and pulmonary capillary wedge pressure were made before and after anesthesia induction, after surgical incision, during cardiopulmonary bypass, and 2, 4, and 24 hours after the operation. The venous compliance of the total body venous bed was measured at the end of the operation. In all patients the total net fluid balance was determined during bypass and in the postoperative period. In both groups plasma catecholamine levels increased 5 minutes after institution of bypass (epinephrine 176 +/- 56 to 611 +/- 108 pg/ml and norepinephrine 231 +/- 48 to 518 +/- 100 pg/ml in group A; epinephrine 168 +/- 40 to 444 +/- 100 pg/ml and norepinephrine 162 +/- 44 to 267 +/- 52 pg/ml in group B). The maximum catecholamine level was measured between the end of bypass and 2 hours after the end of bypass (epinephrine 1489 +/- 169 pg/ml and norepinephrine 1542 +/- 108 pg/ml in group A; epinephrine 990 +/- 134 pg/ml and norepinephrine 934 +/- 197 pg/ml in group B). During the same period mean arterial pressure and total peripheral resistance were also significantly higher in group A than in group B mean arterial pressure, 61.4 +/- 3 versus 53.6 +/- 3, p less than 0.06; total peripheral resistance, 1055 +/- 60 versus 899 +/- 45, p less than 0.01). The venous compliance was significantly higher in group A than in group B (2.4 +/- 0.3 versus 1.2 +/- 0.3 ml/mm Hg/kg body weight). The intraoperative and perioperative net fluid balance were significantly higher in group A than in group B (p less than 0.005). The average postoperative tracheal intubation time was also significantly longer in group A than in group B (4.6 +/- 1.2 hours versus 2.7 +/- 0.8 hours, p less than 0.001). No significant difference was detected in either hemoglobin or plasma free hemoglobin content between the two groups postoperatively. The results suggest that pulsatile perfusion, when compared with nonpulsatile perfusion, can attenuate the catecholamine stress response to cardiopulmonary bypass, reduce the fluid overloading of patients, and improve the postoperative recovery period as evaluated by tracheal intubation time.