Cytomegalovirus infections after open heart surgery. A prospective study

A Prospective Monitoring Study of Cytomegalovirus Infection in Non-Immunosuppressed Critical Heart Surgery Patients

Background

Reactivation of cytomegalovirus (CMV) has been reported occasionally in immnunocompetent patients in the intensive care unit (ICU). The epidemiology and association of CMV infection with adverse outcome is not well defined in this population. Patients undergoing major heart surgery (MHS) are at a particularly high risk of infection. CMV infection has not been systematically monitored in MSH-ICU patients.

Methods

We assessed CMV plasma viremia weekly using a quantitative polymerase chain reaction assay in a prospective cohort of immunocompetent adults admitted to the MHS-ICU for at least 72 hours between October 2012 and May 2013. Risk factors for CMV infection and its potential association with continued hospitalization or death by day 30 (composited endpoint) were assessed using univariate and multivariate logistic regression analyses.

Results

CMV viremia at any level was recorded in 16.5% of patients at a median of 17 days (range, 3-54 days) after admission to the MHS-ICU. Diabetes (adjusted OR, 5.6; 95% CI, 1.8-17.4; p=0.003) and transfusion requirement (>10 units) (adjusted OR, 13.7; 95% CI, 3.9-47.8; p<0.001) were independent risk factors associated with CMV reactivation. Reactivation of CMV at any level was independently associated with the composite endpoint (adjusted OR, 12.1; 95% CI, 2.3-64; p=0.003).

Conclusion

Reactivation of CMV is relatively frequent in immunocompetent patients undergoing MHS and is associated with prolonged hospitalization or death.

Postpericardiotomy syndrome: no evidence for a viral etiology

BACKGROUND

Postpericardiotomy syndrome has been considered a disorder induced by viral infection. This conclusion is based on serologic criterions, but these may be unreliable following either cardiopulmonary bypass or transfusion therapy. Previous studies have not verified the proposed etiology either by isolation of viruses, or by detection of their genome. We sought, therefore, to clarify the role, if any, of viruses in this syndrome.

METHODS AND RESULTS

We studied prospectively 149 children aged from 6 months to 16 years who were undergoing open heart surgery. Blood samples were collected from all prior to operation, and again 7 to 10 days post-operatively, and 47 were sampled at the time of development of symptoms of pericardial involvement. Serums were analyzed for the presence of IgM and IgG antibodies to cytomegalovirus, herpes simplex virus, and Epstein-Barr virus. The polymerase chain reaction was used for amplification when assessing the genome of the enteroviruses. Cultures for viruses were established on samples of stool, urine, and throat swabs collected 7 days post-operatively, and at the time of postpericardial symptoms. Pericardial fluid obtained from 5 patients with the syndrome was cultured for viruses, and tested for enterovirus genome. On the basis of clinical and echocardiographic findings, 34 children were determined to have definite evidence of the syndrome, 13 were considered to have possible evidence, and the results from these patients were compared to those from patients with no pericardial symptoms, the latter being matched for age and transfusion status. We isolated viruses from one or more sites in five patients with definite evidence (16%), from one (9%) of those with possible evidence, and from seven (19%) of the controls. All serums and pericardial samples were negative for enterovirus genome. IgM antibodies were found in only 5 patients, three with symptoms of pericardial involvement and two without. Rates of seroconversion to IgG for the viruses were lower in the patients with symptoms of pericardial involvement compared to controls, but were strongly influenced by transfusion status.

CONCLUSION

Our study has provided no evidence to support a viral etiology for the postpericardiotomy syndrome.

Cytomegalovirus studies on blood donors in north-east Scotland and a review of UK data

The epidemiology of cytomegalovirus (CMV) infection as assessed by CMV antibody testing varies significantly in different parts of the world and also in different regions of a country. A study was therefore carried out to assess the prevalence of CMV antibody in our blood donors, looking in particular at different subgroups of donors as divided by age, sex and social class, to see how we could maximise the yield of CMV-negative blood from our testing. It was shown that patterns of CMV infection in the North East of Scotland followed well-established norms. Data from other Regional Transfusion Centres within the UK were also collected for comparison.

Incidence and morbidity of cytomegaloviral infection in patients with mediastinitis following cardiac surgery

To determine the incidence and morbidity of infections with CMV associated with mediastinitis after conventional cardiac surgery, 115 consecutive adult patients with mediastinitis were evaluated with viral cultures of blood and urine. Shedding of CMV was seen in 29 patients (25 percent) within a mean period of 37 +/- 22 days after cardiopulmonary bypass. Viremia was documented in 79 percent (23) of these 29 patients. Acute renal failure and enzymatic abnormalities (AST and LDH) were significantly more common in patients with virologically proven infection with CMV (p less than 0.05). In patients who survived the initial period of bacterial infection, major differences in their clinical course were observed according to their virologic status. After the 15th day of hospitalization following the débridement, the persistence of local infection was more frequent (p less than 0.05) and the mortality was higher (p less than 0.01) in CMV-infected patients. Moreover, the mean duration of hospitalization in the ICU for survivors was 69 +/- 36 days in viral shedders, compared with 48 +/- 27 days in nonshedders (p less than 0.05). Infection with CMV in mediastinitis occurs frequently and is associated with persistence of local infection, prolonged hospitalization, and increased late mortality.

Transfusion-associated viral infections

Viral infections are a frequent occurrence following transfusion of blood products. While generally benign, these infections are capable of causing significant morbidity and mortality. Therefore, it is prudent to follow several general approaches diligently to reduce the risks of these infections in patients undergoing transfusions of blood products. These suggested measures include the following: 1. Prescribe and administer blood and blood products only when absolutely needed. 2. Use volunteer blood donors only. 3. Avoid use of pooled blood products when possible. 4. Use only blood and blood products that have been appropriately tested for HBsAg and HIV. 5. Use ALT determinations to screen blood products and eliminate those with high level. 6. Avoid the use of clotting-factor concentrates but, if necessary, use only those which have been heat-treated. 7. Limit use of leukocyte transfusion. 8. Use only CMV seronegative blood and blood products or frozen deglycerolized red cells in patients at high risk for posttransfusion CMV infection.

Transfusion-transmitted cytomegalovirus infections: significance and control

Cytomegalovirus (CMV) is a herpes virus which can give rise to primary infections, reactivated infections, or reinfections in humans. Seroepidemiologic studies have shown CMV infection to be worldwide with the highest antibody prevalences detected in Third World countries; however, significant regional variations can be seen within a given country. Antibody prevalence varies directly with age and inversely according to socioeconomic status. Numerous prospective studies of blood transfusion recipients carried out since 1966 have shown marked differences in infection rates but relatively little associated disease. Infection rates were highest in seronegative recipients given large amounts of fresh blood. Recently published reports have shown substantially lower infection rates than earlier studies, a change likely to be due to the current practice of transfusing fewer units of older blood. CMV has not been found to play a significant role in the etiology of posttransfusion hepatitis. CMV infections have been found to be an important source of morbidity and mortality in immunocompromised patients. Several studies of transfused, premature infants have shown significant differences in infection rates and disease expression. Seronegative low-birth-weight infants receiving blood from seropositive donors are at greatest risk. Blood from CMV-seronegative donors substantially lowers the risk of infection. Receiving a kidney or heart from a CMV-seropositive donor appears to be a more salient risk factor than blood transfusion in renal and cardiac transplant patients who are also more likely to have symptomatic CMV infections. Leukocyte transfusions have been found to be a significant source of CMV infection and disease in bone marrow transplant patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatal cytomegalovirus infections due to blood

Infants with very low birthweights (less than 1250g) are immunocompromised and have immature hematopoietic systems. They require frequent blood transfusions and have an increased susceptibility to infection. These very low birthweight infants who lack passively acquired antibody against CMV, acquire transfusion-associated CMV infections with a frequency of approximately 30%. These infections are associated with significant morbidity and mortality. The source of these postnatally acquired CMV infections are seropositive blood donors. These infections can be prevented by appropriate donor selection and/or blood processing. Recent but limited data suggests that all infants (regardless of birthweight or the presence of antibody against CMV) should receive CMV seronegative blood products if they are likely to receive multiple transfusions from multiple donors.

Transfusion-associated cytomegalovirus infections in seropositive cardiac surgery patients

To determine whether reinfection with an exogenous strain of cytomegalovirus (CMV) or reactivation of endogenous CMV is responsible for post-transfusion CMV infections in patients previously infected with the virus, seropositive patients were randomised preoperatively to receive red blood-cells (RBCs) from CMV seronegative donors (group A) or from random donors (group B). Each group B patient received at least one seropositive unit. 5 of 46 group A patients and 7 of 48 group B patients had a four-fold or greater increase of IgG antibody to CMV eight to twelve weeks postoperatively. IgG antibody titre did not increase in a third group (group C) of 57 seropositive patients who received no RBCs. 10 of the 12 patients with increased IgG titres also had CMV-specific IgM antibody after transfusion. These results indicate that reactivation accounts for most post-transfusion CMV infections in seropositive adults.

Natural killer cell activity after open-heart surgery

We studied the effects of elective open-heart surgery with cardiopulmonary bypass on peripheral blood natural killer (NK) cell activity in 12 patients with heart disease. Separated mononuclear cells from patients and control cells taken from healthy volunteers were incubated in microtiter plates for 24 h with 3H-thymidine-labelled K 562 cells as target cells. In this test system, higher counts per minute (cpm) values represent a greater number of surviving target cells and thus weaker NK activity. Results of cultures prepared from blood samples taken preoperatively were compared with those taken 2, 7 and 14 days postoperatively. NK cell activity was depressed (P less than 0.01) for 2 days after surgery. NK cell activity in the control samples did not change significantly. The results show an impairment of NK cell activity immediately after open-heart surgery.

Diseases transmitted by blood transfusion

Except for post-transfusion hepatitis (PTH), the transmission of disease by blood transfusion appears to be very limited. There are only a few case reports documenting the transmission of malaria and other parasitic diseases, syphilis, or bacterial infections. The ability to eradicate PTH will depend on the development of sensitive-specific tests for the non-A, non-B agent(s). In the interim, two important steps that might be taken to reduce the incidence of PTH are the careful recruitment of blood donors and, most important, the judicious use of blood and its components.

Severe cytomegalovirus infection in multiply transfused, splenectomized, trauma patients

During a 2-year period 5 previously healthy young men who had undergone splenectomy and received multiple transfusions for trauma had severe cytomegalovirus (CMV) infection. Their illness was characterised by a long period of high fever, severe interstitial pneumonitis with dyspnoea and hypoxaemia, and an unusually high lymphocytosis (12 000-26 000 cells/microliter) with numerous atypical forms. The presumptive diagnosis was based on the patients' seroconversion and viral excretion, on the clinical and haematological findings which were typical of severe CMV infection, and on the absence of other infective organisms. In 1 case widespread CMV pneumonitis was confirmed at necropsy. These observations raise the possibility that splenectomy increases the severity and modifies the pattern of CMV infection, since during the same period no other case of severe CMV infection was observed among a large number of patients who had received multiple transfusions but had not undergone splenectomy.

Cytomegalovirus hepatitis in an artificial kidney unit

Serum hepatitis is a dreaded risk in connection with regular dialysis treatment (RDT). Liver damage, however, can be cuased by other diseases, such as infection with cytomegalovirus (CMV). Two cases in our artificial kidney unit revealed signs of liver damage with increased liver enzyme activity. Case 1, a woman, was on RDT after an unsuccessful renal transplantation, and Case 2, a man, belonged to the staff. Serum hepatitis was initially suspected in both cases, but repeated examinations of the sera revealed no hepatitis B antigen or antibodies (HbAg and HbAb). Later on, both showed a significant increase in antibodies in complement fixations reaction (CF) to CMV-antigen. CMV could be isolated from urine in Case 2. Case 1 had been bilaterally nephrectomized. The symptoms (tiredness, muscle pain and headache) and the course of the disease were mild in both cases and liver enzymes became normal within 1-2 weeks. Twenty out of 31 examined patients and staff had antibodies in CF to CMV-antigen, but in none was there any significant increase. The source of infection may have been transfusion of fresh blood in Case 1, but in Case 2 no particular source could be suspected. Thus, in liver damage CMV-infection may be an etiological alternative. In routine work at artficial kidney unite patients and personnel are regularly examined in respect of bilirubin, liver enzymes, HbAg and HbAb in serum. We recommend also examination of serum for antibodies in CF to CMV-antigen. Until a firm differential diagnosis has been established the patient should be isolated and the dialysis equipments used only by that patient.

Isoimmune haemolysis in pathogenesis of anaemia after cardiac surgery

A patient who had received multiple transfusions developed antiglobulin-positive haemolytic anaemia due to a delayed haemolytic transfusion reaction. Many cases of haemolytic anaemia after cardiac surgery could be explained on this basis.

Infective complications of open-heart surgery and the monitoring of infections by the NBT test

Freeman, R., King, B., and Hambling, M. H. (1973).Thorax, 28, 617-621. Infective complications of open-heart surgery and the monitoring of infections by the NBT test. Seventy-four consecutive patients undergoing open-heart surgery were extensively investigated, preoperatively and postoperatively, for evidence of infection. The incidence of the infective complications encountered is presented, together with discussion on the aetiology of these complications. A previously unrecognized infective complication is described, this being a high incidence of infection with Mycoplasma pneumoniae.

The series also reports an assessment of the nitroblue tetrazolium (NBT) test in these patients, and it is concluded that the system evolved in this series, of minimal chemoprophylaxis and constant monitoring of infection, affords a logical alternative to conventional methods using massive prophylaxis.

Cytomegalovirus antibody production in renal transplant patients

Sera were examined from 50 patients on the renal transplant unit, Cambridge, for antibody against cytomegalovirus by complement fixation and by immunofluorescence for IgG and IgM antibodies.The incidence of antibody on admission was 84% with a possible further 8% so that nearly all had been infected at some time by CMV.43 (86%) patients showed evidence of active infection after admission, 39 by serology and four only from the examination of post-mortem material.Twenty-one patients produced IgM antibody and production was prolonged for years in patients that survived. Antibody production was related both to transplantation and admission to hospital.The evidence indicated that primary CMV infections were rare, that IgM antibody production was the result of active infection and that this could be attributed to reactivation without the need to invoke re-infection as the source although this type of patient is both susceptible and exposed to re-infection.