Combined human cytomegalovirus and hepatitis C virus infections increase the risk of allograft vascular disease in heart transplant recipients

Expanding Heart Transplant in the Era of Direct-Acting Antiviral Therapy for Hepatitis C

Importance

For patients awaiting heart transplant, hepatitis C-positive donors offer an opportunity to expand the donor pool, shorten wait times, and decrease wait-list mortality. While early reported outcomes among few heart transplant recipients have been promising, knowledge of 1-year outcomes in larger cohorts of patients is critical to shared decision-making with patients about this option.

Objective

To better define the association of hepatitis C-positive donors with heart transplant volumes, wait-list duration, the transmission and cure of donor-derived hepatitis C, and morbidity and mortality at 1 year.

Design, Setting, and Participants

This was a prospective, single-center observational study of 80 adult (age 18 years or older) patients who underwent heart transplant using hearts from hepatitis C-positive donors between September 2016 and April 2019 at a large academic medical center. Among donors, who were considered hepatitis C-positive if results from hepatitis C antibody and/or nucleic acid testing were positive, 70 had viremia and 10 were seropositive but did not have viremia. Follow-up was available through May 15, 2019. Comparisons were drawn with patients who underwent transplant with hearts from hepatitis C-negative donors during the same period.

Exposures

In addition to standard posttransplant management, transplant recipients who developed donor-derived hepatitis C infection were treated with direct-acting antivirals.

Main Outcomes and Measures

The main outcomes included wait-list duration and 1-year survival in all patients, and for those who developed donor-derived hepatitis C, the response to direct-acting antiviral treatment.

Results

Of 80 patients, 57 (71.3%) were men, 55 (68.7%) were white, and 17 (26.3%) were black; the median age at transplant was 54.5 years (interquartile range, 46-62 years). Following consent to accept hearts from hepatitis C-exposed donors, the median days to heart transplant was 4 (interquartile range, 1-18). No recipients of donors with negative nucleic acid testing results (10 [12.5%]) developed donor-derived hepatitis C. Of 70 patients who were recipients of donors with positive nucleic acid testing results, 67 (95.7%) developed donor-derived hepatitis C over a median follow-up of 301 days (interquartile range, 142-617). Treatment with direct-acting antivirals was well tolerated and yielded sustained virologic responses in all treated patients. Within the cohort with infection, 1-year patient survival was 90.4%, which was not significantly different compared with the cohort without infection or with patients who received transplants from hepatitis C-negative donors during the same period.

Conclusions and Relevance

In the era of direct-acting antivirals, hepatitis C-positive donors are a viable option to expand the donor pool, potentially reducing wait-list duration and mortality. In heart transplant recipients with donor-derived hepatitis C, infection is well-tolerated and curable, and 1-year survival is equivalent to that in recipients of hepatitis C-negative donors.

Early outcomes using hepatitis C-positive donors for cardiac transplantation in the era of effective direct-acting anti-viral therapies

BACKGROUND

Given the shortage of suitable donor hearts for cardiac transplantation, and the favorable safety and efficacy of current agents used to treat hepatitis C virus (HCV), our institution recently piloted transplantation of select patients using HCV-positive donors.

METHODS

Between September 2016 and March 2017, 12 HCV-naive patients and 1 patient with a history of treated HCV underwent heart transplantation (HT) using hearts from HCV-positive donors after informed consent. Patients who acquired HCV were referred to hepatology and treated with direct-acting anti-viral therapies (DAAs). Data collection and analysis were performed with institutional review board approval.

RESULTS

At the time of HT, mean age of recipients was 53 ± 10 years, and 8 patients (61.5%) were on left ventricular assist device support. After consent to consider an HCV-positive heart, mean time to HT was 11 ± 12 days. Nine of 13 patients (69%) developed HCV viremia after transplant, including 8 who completed DAA treatment and demonstrated cure, as defined by a sustained virologic response 12 weeks after treatment. One patient died during Week 7 of his treatment due to pulmonary embolism. DAAs were well tolerated in all treated patients.

CONCLUSIONS

In the era of highly effective DAAs, the use of HCV-positive donors represents a potential approach to safely expand the donor pool. Additional follow-up is needed to elucidate long-term outcomes.

Can Donors With Prior Hepatitis Be Safely Used for Heart Transplantation?

BACKGROUND

Heart transplantation represents a significant life-saving and increased quality-of-life intervention for patients with refractory cardiac failure. Successful transplantation requires continuous immunosuppression to avoid immune rejection. Unfortunately, persistent viral infections in donors may be transmitted to recipients in the process of heart transplantation. With the severe shortage of available organs and significant waiting list mortality there is a rationale for considering use of organs from donors with evidence of prior hepatitis B and/or hepatitis C infection.

METHODS

Published literature articles were searched using Medline, PaperChase and further review of references in relevant articles on issues related to hepatitis B and hepatitis C and heart transplantation.

RESULTS

Donor and recipient testing for hepatitis B and hepatitis C is important for relative risk assessment. Nucleic acid testing for hepatitis B DNA and hepatitis C RNA represent emerging technologies, which may add valuable information to traditional serologic testing.

CONCLUSIONS

Heart transplant recipient risk may be modified by vaccination against hepatitis B before transplantation. There is currently no available vaccine for hepatitis C. Recently described effective treatments for hepatitis B and hepatitis C provide further rationale for reconsideration of using hearts from donors with evidence of hepatitis B and/or hepatitis C infection.

Infections and solid organ transplant rejection: a cause-and-effect relationship?

Although evidence is far from being conclusive, several studies have suggested that infections could trigger rejection in different transplant settings. In this review we examine the evidence linking cytomegalovirus (CMV), adenovirus, enterovirus, parvovirus, and herpes simplex virus infections to the vasculopathy leading to cardiac allograft rejection, the association between CMV and chronic kidney, lung, and liver graft rejection, and the association of human herpesvirus 6 reactivation with CMV-related disease in kidney and liver transplant recipients. We also review the numerous antiviral prophylactic or pre-emptive treatments in use to control CMV infection, and suggest that they do not limit immune reactions leading to graft rejection or lower the risk of developing post-transplantation atherosclerosis in allograft recipients. Finally, we emphasise the need for prospective, international studies to clarify the role of infections in transplant rejection, to look at virus-to-virus interactions, and to establish specific therapeutic strategies. Such strategies must not rely exclusively on expensive antiviral agents but also on vaccination or other, innovative approaches, such as the use of agents able to inhibit the activity of natural killer cells, which might have an important role in acute allograft rejection.

Immunohistochemical characterization of coronary thrombi in allograft vascular disease

BACKGROUND

Coronary thrombosis is a frequent complication of allograft vascular disease (AVD) in cardiac transplant recipients. No data are available on thrombus composition in these hearts.

METHODS

The present study aimed at characterizing thrombus components in coronary arteries from transplanted hearts with AVD, using single and double immunostain with anti-gpIIb-IIIa, anti-fibrin, and anti-endothelial antibodies. The pathologic series consists of 55 grafts survived longer than 2 months, and obtained from 55 patients deceased (n=44) or undergone repeat transplantation (n=11).

RESULTS

Mural thrombi were found in multiple segments of 75 of 440 total coronary vessels (17%) (recent in 33, organizing in 28, and organized in 14), whereas occlusive thrombi were found in 19 vessels (8 recent and 11 with multichannel pattern of organization). Recent and thin mural thrombi were mostly constituted of CD41a- and CD61-positive platelets; the amount of fibrin progressively increased with the increase of thrombus size. In organizing mural thrombi, gpIIb-IIIa immunostain was still present. Fibrin was the only identifiable thrombus component in old mural thrombi embedded within the intimal lesions. Recent occlusive thrombi immunoreacted both with anti-CD41a and anti-CD61 and with anti-fibrin antibodies, whereas organized occlusive thrombi with multichannel pattern exclusively immunoreacted with anti-fibrin antibodies. Double immunostain showed that mural thrombi were stratified on de-endothelized arterial segments.

CONCLUSIONS

Thrombus composition is related to both type and "age" of thrombus, with platelets as the early and major components of mural microthrombi at one end of the spectrum, and fibrin as the dominant component of occlusive thrombi at the other end.

New strategies for prevention and therapy of cytomegalovirus infection and disease in solid-organ transplant recipients

In the past three decades since the inception of human organ transplantation, cytomegalovirus (CMV) has gained increasing clinical import because it is a common pathogen in the immunocompromised transplant recipient. Patients may suffer from severe manifestations of this infection along with the threat of potential fatality. Additionally, the dynamic evolution of immunosuppressive and antiviral agents has brought forth changes in the natural history of CMV infection and disease. Transplant physicians now face the daunting task of recognizing and managing the changing spectrum of CMV infection and its consequences in the organ recipient. For the microbiology laboratory, the emphasis has been geared toward the development of more sophisticated detection assays, including methods to detect emerging antiviral resistance. The discovery of novel antiviral chemotherapy is an important theme of clinical research. Investigations have also focused on preventative measures for CMV disease in the solid-organ transplant population. In all, while much has been achieved in the overall management of CMV infection, the current understanding of CMV pathogenesis and therapy still leaves much to be learned before success can be claimed.

From plaque biology to clinical setting

Coronary atherosclerosis may cause acute and chronic ischemic syndromes; the former are caused by "acute plaque events," mostly thrombosis complicating vulnerable ruptured plaques, namely severe lesions with large core, thin cap, and weak shoulder infiltrated by activated inflammatory cells. Plaque rupture may also occur in nonischemic settings and is not obligatorily complicated by thrombosis. Furthermore, plaque rupture is not the only thrombus substrate in acute ischemic syndromes: Superficial erosion of fibrous plaques is found in 44% of acute thrombi in sudden coronary deaths and in 25% of those in acute myocardial infarctions. Coronary thrombosis appears to be triggered by superficial intimal inflammation in plaque ulceration and by neointimal hyperplasia in plaque erosion. "Endogenous" and, recently, exogenous factors, particularly infective intracellular organisms, have been proposed as major contributors to plaque inflammation, activation, and vulnerability. Possible exogenous triggers are DNA and RNA viruses and intracellular bacteria such as Chlamydia pneumoniae, which has been identified with microbiological, ultrastructural, immunohistochemical, and molecular tools in a consistent proportion of human plaque samples. Chlamydia increases local thrombogenicity and is associated with an atherogenic lipid profile. Systemic indexes of inflammation, such as PCR, SAA, and fibrinogen, are also increased in acute syndromes and common infectious diseases with high morbidity and minimal clinical impact are good candidates; Helicobacter pylori is a major one. Infectious agents could link local and systemic inflammation: White cells infected in its target tissue could circulate into the flow and be captured, on a specific local trigger, into vessel walls thus stimulating local inflammation.