Cardiac allograft vasculopathy

Nailfold Videocapillaroscopy for Non-Invasive Assessment of Microcirculation and Prognostic Correlation with Endothelial Dysfunction, Cardiovascular Risk Factors, and Non-HLA Antibodies in Heart Transplant Recipients: A Pilot Study

Early identification of allograft vasculopathy and the concomitant elimination of adverse risk factors is essential for improving the long-term prognosis of heart transplant (HTx) recipients with underlying cardiovascular disease (CVD). The major aim of this pilot study was to conduct a non-invasive imaging evaluation of the HTx patient microcirculation by employing nailfold video-capillaroscopy (NVC) in a well-characterized patient and control cohort, and to correlate these data with endothelial cell function, accompanied by studies of traditional cardiovascular risk factors and non-HLA antibodies in HTx recipients. Ten patients undergoing HTx (mean age of 38 ± 14 years) were recruited for the study and compared to a control group of 12 well-matched healthy volunteers (mean age 35 ± 5 years) with normal body mass index (BMI). Detailed medical records were collected from all individuals. NVC was performed using CapillaryScope 200 MEDL4N microscope. For functional readout and correlation analysis, endothelial cell network formation in conjunction with measurements of patient serum levels of vascular endothelial growth factor (VEGF) and non-HLA autoantibodies directed against the angiotensin II type-1-receptor (anti-AT1R-Ab), endothelin-1 type-A-receptor (anti-ETAR-Ab), protease-activated receptor-1 (anti-PAR-1-Ab), and VEGF-A (anti-VEGF-A-Ab) were studied. Our NVC analysis found that the average apical loop diameter of nailfold capillaries was significantly increased in HTx recipients (p = 0.001). In addition, HTx patients with more prominent changes in capillaroscopic patterns were characterized by the presence of traditional cardiovascular risk factors, and HTx patients had increased levels of anti-AT1R-ab, anti-ETAR-ab, and anti-VEGF-A-Ab (p = 0.017, p = 0.025, and p = 0.003, respectively). Capillary diameters most strongly correlated with elevated serum levels of troponin T and triglycerides (R = 0.69, p = 0.028 and R = 0.81, p = 0.004, respectively). In conclusion, we found that an abnormal NVC pattern in HTx patients is associated with traditional CVD risk factors and that NVC is a useful non-invasive tool to conveniently monitor changes in the microvasculature of HTx patients.

Overview of Immunosuppressive Therapy in Solid Organ Transplantation

Mechanisms of rejection, new pharmacologic approaches, and genomic medicine are major foci for current research in transplantation. It is hoped that these new agents and personalized immunosuppression will provide for less toxic regimens that are effective in preventing both acute and chronic allograft rejection. Until new agents are available, practitioners must use various combinations of currently approved agents to find the best regimens for improved long-term outcomes.

Cardiac allograft vasculopathy: a donor or recipient induced pathology?

Cardiac allograft vasculopathy (CAV) is one of the main causes of late-stage heart failure after heart transplantation. CAV is characterized by concentric luminal narrowing of the coronary arteries, but the exact pathogenesis of CAV is still not unraveled. Many researchers show evidence of an allogeneic immune response of the recipient, whereas others show contrasting results in which donor-derived cells induce an immune response against the graft. In addition, fibrosis of the neo-intima can be induced by recipient-derived circulating cells or donor-derived cells. In this review, both donor and recipient sides of the story are described to obtain better insight in the pathogenesis of CAV. Dual outcomes were found regarding the contribution of donor and recipient cells in the initiation of the immune response and the development of fibrosis during CAV. Future research could focus more on the potential synergistic interaction of donor and recipient cells leading to CAV.

Coronary microvasculopathy in heart transplantation: Consequences and therapeutic implications

Despite the progress made in the prevention and treatment of rejection of the transplanted heart, cardiac allograft vasculopathy (CAV) remains the main cause of death in late survival transplanted patients. CAV consists of a progressive diffuse intimal hyperplasia and the proliferation of vascular smooth muscle cells, ending in wall thickening of epicardial vessels, intramyocardial arteries (50-20 μm), arterioles (20-10 μm), and capillaries (< 10 μm). The etiology of CAV remains unclear; both immunologic and non-immunologic mechanisms contribute to endothelial damage with a sustained inflammatory response. The immunological factors involved are Human Leukocyte Antigen compatibility between donor and recipient, alloreactive T cells and the humoral immune system. The non-immunological factors are older donor age, ischemia-reperfusion time, hyperlipidemia and CMV infections. Diagnostic techniques that are able to assess microvascular function are lacking. Intravascular ultrasound and fractional flow reserve, when performed during coronary angiography, are able to detect epicardial coronary artery disease but are not sensitive enough to assess microvascular changes. Some authors have proposed an index of microcirculatory resistance during maximal hyperemia, which is calculated by dividing pressure by flow (distal pressure multiplied by the hyperemic mean transit time). Non-invasive methods to assess coronary physiology are stress echocardiography, coronary flow reserve by transthoracic Doppler echocardiography, single photon emission computed tomography, and perfusion cardiac magnetic resonance. In this review, we intend to analyze the mechanisms, consequences and therapeutic implications of microvascular dysfunction, including an extended citation of relevant literature data.

Effect of everolimus on the immunomodulation of the human neutrophil inflammatory response and activation

The primary cause of mortality at 5 years following a cardiac transplantation is the development of atherosclerosis, termed coronary allograft vasculopathy (CAV). This pathology is characterized by diffused intimal hyperplasia and emanates from coronary arterial injuries caused by immune inflammatory cells. Neutrophils play an important role in this inflammatory process; however, their potential participation in the pathogenesis of CAV is poorly understood. Despite their essential contribution to the prevention of graft rejection, immunosuppressive drugs could have detrimental effects owing to their pro-inflammatory activities. Thus, we investigated the impact of different immunosuppressive drugs on the inflammatory response of neutrophils isolated from the blood of healthy volunteers. Under basal conditions, mammalian target of rapamycin (mTOR) inhibitors (sirolimus and everolimus) had the most potent anti-inflammatory effect, decreasing both IL-8 release (≈−80%) and vascular endothelial growth factor (VEGF) release (≈−65%) and preserving the release of the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RA). In TNF-α-treated neutrophils, pre-incubation with everolimus provided the most potent effect, simultaneously reducing the release of both VEGF and IL-8 while doubling the release of IL-1RA. This latter effect of everolimus was maintained even when administered in combination with other immunosuppressive drugs. Sirolimus and everolimus decreased the tumor necrosis factor (TNF)-α-induced adhesion of neutrophils to human endothelial cells and human extracellular matrix. This effect was largely dependent on the ability of these compounds to alter β₂-integrin/CD18 activation. Our results suggest a potential mechanism for the beneficial effect of everolimus in the prevention of CAV in heart transplant recipients.

Granulocyte colony-stimulating factor therapy is associated with a reduced incidence of acute rejection episodes or allograft vasculopathy in heart transplant recipients

BACKGROUND

We evaluated the potential effects of granulocyte colony-simulating factor (G- CSF) on the incidence of rejection and allograft vasculopathy in heart transplant recipients.

METHODS

Of 247 patients undergoing heart transplantation from 2000 to 2007, 52 (21%) developed leukopenia (white blood cell [WBC] <2.5 × 10(9) cells/L) in the absence of active infection, rejection, or malignancy. In 24 (46%) patients a clinical decision was made to treat the leukopenia with G-CSF (G-CSF group), and 28 (54%) Patients received no G-CSF (non-GCSF group). Patients followed up for 1 year after the period of leukopenia were assessed for allograft vasculopathy and acute rejection incidence.

RESULTS

At baseline, the G-CSF group and the non-GCSF group did not differ in age, gender, race, heart failure etiology, creatinine, left ventricular ejection fraction (LVEF) or immunosupressive regimen. During 1-year follow-up there were no deaths in the G-CSF group, and 1 death in the non-GCSF group (P = .34). The incidence of rejection or progressive allograft vasculopathy was lower in the G-CSF group when compared with the non-GCSF group (2 [8%] vs 15 [53%]; P < .01). Multivariate analysis identified both prior rejection episodes and G-CSF therapy as factors associated with the combined end-point of rejection or progressive allograft vasculopathy (odds ratio [OR] = 7.89 [1.67-37.2] and OR = 0.09 [0.02-0.52], respectively).

CONCLUSIONS

G-CSF therapy appears to be associated with a decreased incidence of acute rejection episodes or allograft vasculopathy in heart transplant recipients, suggesting a potential immunomodulatory effect of G-CSF.

Endothelin-1 Is a Key Mediator of Coronary Vasoconstriction in Patients With Transplant Coronary Arteriosclerosis

Background— Transplant coronary arteriosclerosis (TCA) is the principal long-term complication in cardiac transplant recipients. The mediators responsible for vascular proliferation and vasoconstriction typical of TCA remain largely unknown. We tested whether endothelin-1 (ET-1), a potent vasoconstrictor and mitogen, contributes to the pathogenesis and manifestations of TCA.

Methods and Results— BQ-123, an ET-1 receptor-A antagonist, was infused into a coronary artery (40 nmol/min for 60 minutes) of 18 subjects, 6�4 years after transplantation. Vasomotor responses were measured in the infused artery and in a noninfused control artery in patients with (n=10) and without (n=8) advanced TCA (108 total coronary segments). Changes in diameters were compared at 15-minute intervals up to 60 minutes. Contribution of ET-1 to coronary constrictor tone was assessed by comparing vasodilation from BQ-123 with that of the maximal vasodilator nitroglycerin (200-μg intracoronary bolus).

BQ-123 dilated coronary arteries of transplanted patients (8.4% at 60 minutes versus −0.4% in noninfused arteries, P <0.001). Dilation was greater for arteries with advanced TCA defined as diameter stenosis ≥15% (dilation 15.2% with versus 0.6% without advanced TCA, P =0.004). Judged against the response to nitroglycerin, ET-1 accounted for 53.2% of coronary tone in advanced TCA but only 12.9% without advanced TCA.

Conclusions— This study shows for the first time in humans that ET-1 is an important mediator of coronary vasoconstriction in TCA and accounts for >50% of the increased vasomotor tone. Therapeutic targeting of ET-1 may retard the development of TCA.

Dual-source CT for visualization of the coronary arteries in heart transplant patients with high heart rates

OBJECTIVE

The purpose of this study was to evaluate the quality of dual-source CT images of the coronary arteries in heart transplant recipients with high heart rates.

SUBJECTS AND METHODS

Contrast-enhanced dual-source CT coronary angiography was performed on 23 heart transplant recipients (20 men, three women; mean age, 61.1 +/- 12.8 years). Data sets were reconstructed in 5% steps from 30% to 80% of the R-R interval. Two blinded independent readers using a 5-point scale (0, not evaluative; 4, excellent quality) assessed the quality of images of coronary segments.

RESULTS

The mean heart rate during scanning was 89.2 +/- 10.4 beats/min. Interobserver agreement on the quality of images of the whole coronary tree was a kappa value of 0.78 and for selection of the optimal reconstruction interval was a kappa value of 0.82. The optimal reconstruction interval was systole in 17 (74%) of the 23 of heart transplant recipients. At the best reconstruction interval, diagnostic image quality (score >or= 2) was obtained in 92.1% (303 of 329) of the coronary artery segments. The mean image quality score for the whole coronary tree was 3.1 +/- 1.01. No significant correlation between mean heart rate (rho = 0.31) or heart rate variability (rho = 0.23) and overall image quality score was observed (p = not significant).

CONCLUSION

Dual-source CT acquisition yields coronary angiograms of diagnostic quality in heart transplant recipients. Mean heart rate and heart rate variability during scanning do not have a negative effect on the overall quality of images of the coronary arteries.

AP-1 and STAT-1 decoy oligodeoxynucleotides attenuate transplant vasculopathy in rat cardiac allografts

AIMS

Cardiac allograft vasculopathy (CAV) continues to be an unsolved clinical problem requiring the development of new therapeutic strategies. We have previously demonstrated that ex vivo donor allograft treatment with decoy oligodeoxynucleotides (ODN) targeting the transcription factors, activator protein-1 (AP-1) or signal transducer and activator of transcription-1 (STAT-1), delays acute rejection and prolongs cardiac allograft survival. Here, we investigated whether this treatment regime also prevents the occurrence of CAV in a fully allogeneic rat heart transplantation model.

METHODS AND RESULTS

Wistar-Furth rat cardiac allografts were perfused ex vivo with AP-1 decoy ODN, STAT-1 decoy ODN, or buffer solution and transplanted into the abdomen of Lewis rats immunosuppressed with cyclosporine. Treatment with both decoy ODNs but not vehicle significantly attenuated the incidence and severity of CAV. Laser-assisted microdissection/real-time polymerase chain reaction as well as immunohistochemistry analyses revealed a significant increase in CD40 abundance in the coronary endothelial cells and medial smooth muscle cells on day 1 post transplantation which was virtually abolished upon AP-1 or STAT-1 decoy ODN treatment. While the AP-1 decoy ODN primarily attenuated basal CD40 expression, the STAT-1 decoy ODN suppressed tumour necrosis factor-alpha-/interferon-gamma-stimulated expression of CD40 in rat native endothelial cells.

CONCLUSION

Treating donor hearts with decoy ODNs neutralizing AP-1 or STAT-1 at the time of transplantation prevents upregulation of CD40 expression in the graft coronary arteries and effectively inhibits CAV.

Update on cardiac transplantation pathology

CONTEXT

The endomyocardial biopsy is the mainstay for monitoring acute allograft rejection in heart transplantation. Objective and accurate assessment of cellular and humoral types of rejection is important to optimize immunosuppressive therapy, avoid therapeutic complications, and improve patient outcome. The grading system for evaluation of heart transplant biopsies published in 1990 was revised in 2004 after more than a decade of implementation.

OBJECTIVE

In this review, we focus on a practical approach to the evaluation of human heart transplant biopsies as diagnostic surgical pathologic specimens. We discuss the revised International Society of Heart and Lung Transplantation working formulation.

DATA SOURCES

We reviewed pertinent literature, incorporating ideas and vast experience of participants in various work groups that led to the revision of the 1990 grading system.

CONCLUSIONS

The grading system for cellular rejection is presented with detailed light microscopic morphology and comparison of the 1990 and 2004 International Society of Heart and Lung Transplantation working formulations. We show how the pathologic recognition of cellular rejection and antibody-mediated rejection has evolved. We emphasize the interpretation of immunostains for complement components C4d and C3d in the diagnosis of antibody-mediated rejection. Evidence of regulation of complement activation in human heart transplant biopsies is presented in this context. We also discuss the pitfalls, caveats, and artifacts in the interpretation of allograft endomyocardial biopsies. Lastly, we discuss the pathology of human cardiac allograft vasculopathy in practical detail.

Elevated uric acid levels predict allograft vasculopathy in cardiac transplant recipients

BACKGROUND

Cardiac allograft vasculopathy (CAV) poses the greatest threat to the long-term survival of cardiac transplant recipients, and these individuals often exhibit elevated levels of uric acid (UA), a stimulator of T cells. We hypothesized that hyperuricemia is associated with CAV in cardiac transplant recipients.

METHODS

UA levels were measured in cardiac transplant recipients between January 2003 and January 2005. Surveillance cardiac catheterizations performed 3 months to 1 year after UA measurement were reviewed. The relationship between UA and CAV was adjusted for possible confounders with propensity scores and confirmed with goodness-of-fit tests.

RESULTS

The 105 patients included in this study were a median 63.3 months post-transplant and their left heart catheterizations were performed a median 5.6 months after UA measurement. Focal stenosis was evident in 25 angiograms and 31 showed distal pruning of the coronary arteries. Compared with the lowest quartile of UA, the highest quartile had an increased risk of CAV: odds ratio (OR) 6.11 (95% CI 1.47 to 25.5; p = 0.013) for focal stenosis and OR 4.60 (95% CI 1.34 to 15.8; p = 0.015) for distal pruning. After adjustment, this relationship persisted for both focal stenosis (OR 5.53, 95% confidence interval [CI] 1.29 to 23.7; p = 0.021) and distal pruning (OR 4.21, 95% CI 1.15 to 15.4; p = 0.029).

CONCLUSIONS

Elevated UA confers an increased risk of CAV. This association may be causal, with pathophysiologic implications for the role of hyperuricemia in allograft failure and, if substantiated, could have clinical implications for the use of xanthine oxidase inhibitors in cardiac transplant recipients.

The universal NF-kappaB inhibitor a20 protects from transplant vasculopathy by differentially affecting apoptosis in endothelial and smooth muscle cells

Transplant vasculopathy (TV) is an accelerated form of atherosclerosis resulting in chronic rejection of vascularized allografts. The causes of TV are multifactorial and integrate at the level of the vascular wall, leading to a phenotypic switch of endothelial cells (ECs) and smooth muscle cells (SMCs). A20 is a NF-kappaB-dependent stress response gene in ECs and SMCs with potent anti-inflammatory effect in both cell types through blockade of NF-kappaB. A20 expression in ECs and SMCs correlates with the absence of TV in rat kidney allografts and long-term functioning human kidney allografts. We demonstrate that A20 protects ECs from tumor necrosis factor, Fas, and natural killer cell-mediated apoptosis by inhibiting proteolytic cleavage of caspase 8. A20 also safeguards ECs from complement-mediated necrosis. Hence, effectively shutting down cell death pathways initiated by inflammatory and immune offenders associated with TV. In contrast, A20 sensitizes SMCs to cytokine and Fas-mediated apoptosis through a novel nitric oxide (NO)-dependent mechanism. The unexpected proapoptotic effect of A20 in SMCs translates in vivo by the regression of established neointimal carotid lesions following balloon angioplasty in rats. Antedating apoptosis of SMCs, expression of the inducible NO synthase increases in A20-expressing neointimal SMCs, corroborating the involvement of NO in causing the proapoptotic effect of A20 in SMCs. Combined anti-inflammatory and anti- or proapoptotic functions of A20 in ECs and SMCs respectively qualify the positive effect of A20 upon vascular remodeling and healing. We propose that A20-based therapies may be effective in prevention and treatment of TV.

C. The universal NF-kappaB inhibitor a20 protects from transplant vasculopathy by differentially affecting apoptosis in endothelial and smooth muscle cells

Transplant vasculopathy (TV) is an accelerated form of atherosclerosis resulting in chronic rejection of vascularized allografts. The causes of TV are multifactorial and integrate at the level of the vascular wall, leading to a phenotypic switch of endothelial cells (ECs) and smooth muscle cells (SMCs). A20 is a NF-kappaB-dependent stress response gene in ECs and SMCs with potent anti-inflammatory effect in both cell types through blockade of NF-kappaB. A20 expression in ECs and SMCs correlates with the absence of TV in rat kidney allografts and long-term functioning human kidney allografts. We demonstrate that A20 protects ECs from tumor necrosis factor, Fas, and natural killer cell-mediated apoptosis by inhibiting proteolytic cleavage of caspase 8. A20 also safeguards ECs from complement-mediated necrosis. Hence, effectively shutting down cell death pathways initiated by inflammatory and immune offenders associated with TV. In contrast, A20 sensitizes SMCs to cytokine and Fas-mediated apoptosis through a novel nitric oxide (NO)-dependent mechanism. The unexpected proapoptotic effect of A20 in SMCs translates in vivo by the regression of established neointimal carotid lesions following balloon angioplasty in rats. Antedating apoptosis of SMCs, expression of the inducible NO synthase increases in A20-expressing neointimal SMCs, corroborating the involvement of NO in causing the proapoptotic effect of A20 in SMCs. Combined anti-inflammatory and anti- or proapoptotic functions of A20 in ECs and SMCs respectively qualify the positive effect of A20 upon vascular remodeling and healing. We propose that A20-based therapies may be effective in prevention and treatment of TV.

The Preoperative Evaluation of the Transplanted Patient for Nontransplant Surgery

With the improved success of solid-organ transplantation, there has been an increased willingness to transplant individuals previously felt to be unsuitable for such procedures. Factors such as age and various medical comorbidities are no longer considered contraindications to transplantation, and hence, an increasing number of recipients may require medical care not specifically related to the transplant. After transplantation, many of these patients may require elective or emergent surgery, making it important for all surgeons to be familiar with the factors that may influence surgical outcomes in this population, asa well asa factors that affect postoperative care. Most transplant centres use a team approach to manage these complex patients, relying on medical professionals experienced in their care and management. Close interaction with the transplant team is likely the single most important step in preparing the transplanted patient for surgery and managing their postoperative care.

Protective genes in the vessel wall: Modulators of graft survival and function

Protecting a vascularized graft from transplant arteriosclerosis requires inhibition of host immune effectors, but protective responses emanating from the graft aimed at maintaining/restoring "homeostasis" might be equally important. Expression of the "protective" genes A20, heme-oxygenase-1 (HO-1), Bcl-xL, inducible nitric oxide synthase (iNOS), and others in the vessel wall of rodent allografts and xenografts correlates with absence of transplant arteriosclerosis. Given the antiapoptotic and anti-inflammatory functions of these genes in endothelial cells and their anti-inflammatory/antiproliferative and sometimes proapoptotic function in neointimal smooth muscle cells, we hypothesize that their expression survives to limit graft injury by maintaining vascular integrity, controlling inflammation and promoting healing. Beyond this beneficial effect, their expression in the vessel wall may also positively impact the alloimmune response.

Detection of transplant coronary artery disease using multidetector computed tomography with adaptative multisegment reconstruction

OBJECTIVES

This study sought to determine whether multidetector computed tomography (MDCT) may be able to detect occlusive coronary disease in transplanted hearts.

BACKGROUND

In heart transplant recipients, asymptomatic coronary disease requiring frequent surveillance commonly develops. Recent advancements in MDCT allow for noninvasive assessment of the coronary vessels.

METHODS

Electrocardiogram-gated contrast-enhanced MDCT scans (16 x 0.75-mm detectors, 420 ms rotation, 100 ml contrast) with multisegment reconstruction were performed on 54 transplant recipients within 6 +/- 11 days of quantitative coronary angiography (QCA). Heart rate at the time of the scan was 90 +/- 11 beats/min. Coronary arterial segments >1.5 mm in diameter were analyzed by independent investigators.

RESULTS

There was a good correlation between MDCT and QCA percent stenosis (r = 0.75, p < 0.01, SEE = 15%). Of the 791 segments identified by QCA, 754 (95%) were analyzable by MDCT. The sensitivity, specificity, and positive and negative predictive values of MDCT compared with QCA for the detection of segments with significant (>50%) stenosis were 86%, 99%, 81%, and 99%, respectively. The MDCT correctly identified 15 of the 16 (94%) transplant patients classified by QCA as having occlusive coronary artery disease and 29 of the 37 patients without significant stenosis (78%). In 1 patient who received intravenous beta-blockers, transient bradycardia requiring temporary pacing developed, but there were no other complications.

CONCLUSIONS

Detection of occlusive coronary disease in heart transplant recipients with elevated resting heart rate by MDCT is feasible using multicycle reconstruction. The need for surveillance invasive coronary angiography in transplant recipients might be mitigated by use of MDCT.

In-stent restenosis and remote coronary lesion progression are coupled in cardiac transplant vasculopathy but not in native coronary artery disease

OBJECTIVES

The purpose of this study was to describe the clinical, angiographic, and histological features of concomitant in-stent restenosis (ISR) and cardiac allograft vasculopathy (CAV) progression.

BACKGROUND

Cardiac allograft vasculopathy is a major challenge to long-term success of heart transplantation. Coronary stenting for CAV is hampered by ISR.

METHODS

Quantitative coronary angiography compared late lumen loss (LL) at stented and reference, non-stented segments during 1-year follow-up in post-heart transplant and control atherosclerosis patients. Stented and non-stented arteries with CAV were also obtained post-mortem for immunohistochemical analysis.

RESULTS

In 37 stented lesions (25 patients), 1-year binary restenosis occurred in 37.8%. Patients with ISR had higher long-term cardiac death/myocardial infarction rates than patients without ISR (53.8% vs. 9.1%, p = 0.03). In the same 25 patients, 34 CAV lesions with non-significant obstructions were identified as reference controls. After 1 year, patients who developed ISR also had more control lesion LL (0.78 +/- 0.38 mm vs. 0.39 +/- 0.27 mm, p < 0.006) compared to patients without ISR. In the post-transplant patients, in-stent LL was closely coupled to control segment LL (R(2) = 0.63, p < 0.05). Conversely, in native atherosclerosis patients, ISR and remote disease progression were not correlated. Histological staining of stented and control arteries from CAV patients revealed similar pathologies common to ISR and non-intervened CAV segments.

CONCLUSIONS

Progression of CAV at non-intervened segments and ISR correlate strongly and share common histopathology. Optimized treatment for patients with aggressive CAV needs to address the widespread nature of this disease, even when it presents as an initially focal lesion.

Is bridging to transplantation with a left ventricular assist device a risk factor for transplant coronary artery disease?

BACKGROUND

Left ventricular assist device (LVAD) support is associated with coagulopathy, bleeding, increased blood transfusion, and increased anti-HLA antibody production. Increased anti-HLA antibody production is associated with early transplant rejection, transplant coronary artery disease (CAD), and decreased post-transplant survival rates. We asked whether bridging to transplantation with an LVAD increases the risk of transplant CAD.

METHODS

We reviewed data for all adults (>18 years old) who underwent heart transplantation at our institution between 1988 and 2000. After exclusion of transplant recipients who survived <3 years, we divided the remaining cohort into 2 groups: those bridged to transplantation with LVADs (mean duration of support, 149 +/- 107 days, n = 29) and those in United Network for Organ Sharing Status 1 bridged to transplantation without LVADs (controls, n = 86). We compared groups in terms of disease cause, age, sex, donor age, panel-reactive antibody testing, crossmatching, pre- and post-transplant cholesterol concentrations, diagnosis of diabetes mellitus or treated hypertension, infections, calcium channel blocker use, transplant rejection, ischemic time, cytomegalovirus infection, pre-transplant transfusion, and incidence of transplant CAD (defined as any coronary lesion identified by coronary angiography). We considered p < 0.05 to be significant.

RESULTS

The bridged and control groups were similar in all respects except mean ischemic time (217 +/- 58 minutes vs 179 +/- 67 minutes, p = 0.007), post-transplant cholesterol concentration (212 +/- 55 mg/dl vs 171 +/- 66 mg/dl, p = 0.007), and pre-transplant transfusion incidence (100% vs 22%, p < 0.001). The incidence of transplant CAD was similar in both groups during a 3-year follow-up period (28% vs 17%, p = 0.238) and during total follow-up (34% vs 35%, p = 0.969). Multivariate logistic regression analysis identified cholesterol concentration at 1 year after transplantation as a significant predictor of CAD at 3 years after heart transplantation (p = 0.0029, odds ratio = 0.984).

CONCLUSIONS

Bridging to transplantation with an LVAD does not increase the risk of transplant CAD. Nevertheless, aggressive prophylactic therapy to minimize potential risk factors for transplant CAD, such as increased cholesterol concentration, is warranted in all transplant recipients.

Re-Stenosis of a Sirolimus-Coated Stent in a Heart Transplant Recipient With Allograft Vasculopathy

We report the first case of in-stent re-stenosis in a sirolimus-coated stent in a heart transplant recipient with allograft vasculopathy. A 54-year-old male transplant recipient with new lesions in the left anterior descending artery detected during a routine surveillance catheterization was treated with two sirolimus-coated stents. Three months later he presented with dyspnea on exertion, and a repeat left heart catheterization demonstrated a focal area of in-stent stenosis in the proximal stent, which was treated with a cutting balloon.

Outcomes and Complications After Heart Transplantation

In more than 35 years of experience with heart transplantation, improvements in patient selection, surgical techniques, organ preservation, and postoperative management have increased survival rates and reduced complications. However, a number of significant complications continue, limiting the benefit of heart transplantation as the long-term solution for patients. Current survival rates are 83% at 1 year and 72% at 5 years, with 50% of patients surviving 9.4 years or more. Recipient and donor characteristics influence survival outcome. Primary graft dysfunction is the most frequent cause of death during the first 30 days. The function of the transplanted heart allows return to pre-illness activities, though denervation limits peak exercise capacity. Advances in immunosuppressive medications have decreased the incidence and severity of rejection, though only recently have shown promise in attenuating the incidence of cardiac graft vasculopathy, the major complication limiting long-term graft function. This review addresses current outcomes and the short- and long-term complications of heart transplantation.

Effect of age on lipid profiles in pediatric heart transplant recipients

This study's objectives were to determine if pediatric orthotopic heart transplant (OHT) recipients over all ages develop hyperlipidemia and, secondarily, to identify the effects of immunosuppressive agents and statins on lipid profiles in these patients. Retrospective chart review was performed for pediatric patients transplanted between January 1987 and June 2002. Of the 100 OHTs performed, 50 patients satisfied the inclusion criteria and were grouped by age at OHT as follows: group 1 (n = 16): 0-4 yr; group 2 (n = 10): 5-9 yr; group 3 (n = 15): 10-14 yr; group 4 (n = 9): 15-18 yr. There were 2789 lipid levels recorded, and each patient had an average of 14 post-OHT lipoprotein panels measured. Post-OHT total cholesterol and low-density lipoprotein (LDL) levels were significantly greater than those of the general population for the entire follow-up period in all age groups, except for LDL levels in group 2. Cyclosporin level and prednisone dose were positively associated with total cholesterol and LDL levels (p < 0.03). Statins significantly decreased total cholesterol and LDL levels (p < 0.001). Hyperlipidemia affects OHT patients of all ages. Even the youngest patients may benefit from immunosuppression using an alternative to cyclosporin, such as tacrolimus, and steroid-free regimens, which may improve lipid profiles. Once safety and efficacy data are available, all age groups may benefit from statins.

Cyclosporine treatment of high dose and long duration reduces the severity of graft coronary artery disease in rodent cardiac allografts

BACKGROUND

Graft coronary artery disease (GCAD) limits allograft survival after cardiac transplantation. The objective of this study was to correlate GCAD with the level of immunosuppression in an established allogeneic rodent cardiac chronic rejection model to better understand the mechanisms of GCAD in this system.

METHODS

Donor PVG hearts were transplanted into the abdomen of ACI rats. Six recipient groups received either 10, 7.5 or 5 mg/kg/day of oral cyclosporine (CsA), for 90 (10 mg/90 d, 7.5 mg/90 d, 5 mg/90 d) or 10 days (10 mg/10 d, 7.5 mg/10 d, 5 mg/10 d; n = 10 all groups), and grafts procured on Day 90. GCAD was assessed by histology for percent luminal narrowing (%LN), percent affected vessels (%AV) and intima/media ratio (I/M ratio). Sections were stained for ED1-positive macrophages and MHC Class II-positive cells.

RESULTS

The 10 mg/90 d treatment group showed significantly reduced GCAD compared with the 5mg/10d treatment group (%LN = 4.3 +/- 3.1% vs 39 +/- 11.9%, p < 0.05). The 7.5 mg/90 d group had a reduced %LN and I/M ratio compared with the 5 mg/10 d group (%LN = 8.0 +/- 3.5% vs 39 +/- 11.9%, p < 0.05; I/M ratio = 0.06 +/- 0.02 vs 0.41 +/- 0.14, p < 0.05). There was a trend toward reduction of GCAD with both increasing the dose of CsA as well as the duration of treatment. Continuous treatment with CsA reduced perivascular macrophage and MHC II cell infiltration. Macrophage infiltrates correlated strongly with GCAD (R(2) > 0.90, p < 0.01), and MHC II infiltrates showed a weak correlation, although not statistically significant (R(2) > 0.56, p = NS).

CONCLUSIONS

This study further defines the effect of cyclosporine on GCAD in this cardiac transplantation model. In this system, higher dose and longer duration of treatment with CsA markedly reduces macrophage and MHC II infiltration, correlating with diminished GCAD. However, increasing dose and duration of CsA did not completely eliminate the development of GCAD. Non-immunologic factors could contribute to this occurrence.

Long-term safety of intravascular ultrasound in nontransplant, nonintervened, atherosclerotic coronary arteries

OBJECTIVES

The goal of this study was to demonstrate that intravascular ultrasound (IVUS) examination of native coronary arteries does not result in an acceleration of the atherosclerotic process.

BACKGROUND

Intravascular ultrasound is increasingly used to assess the effects of pharmacologic agents on atherosclerosis.

METHODS

Intravascular ultrasound examinations of one coronary artery and coronary angiography were performed in 525 patients at baseline. Patients then underwent a follow-up angiogram 18 to 24 months later. All end points were evaluated in IVUS-related and non-IVUS arteries using quantitative coronary analysis. The study end points were the coronary change score (per-patient mean of minimum lumen diameter changes for all lesions measured), occurrence of new coronary lesions, and progression of preexistent lesions at follow-up. Acute angiographic and clinical complications were also analyzed.

RESULTS

Coronary change score was -0.06 +/- 0.23 mm and -0.05 +/- 0.21 mm for IVUS-related and non-IVUS arteries, respectively (p = 0.35). The increase in percent diameter stenosis from baseline to follow-up was 0.8 +/- 6.7% and 1.2 +/- 7.0% in the IVUS-related and non-IVUS arteries (p = 0.29). New lesions occurred in 3.6% and 3.9% of IVUS-related and non-IVUS arteries, respectively (p = 0.84). When all coronary lesions were considered, the incidence of lesion progression was not significantly different between IVUS-related (11.6%) and non-IVUS (9.8%) arteries. Coronary spasm occurred in 1.9% of IVUS procedures, and there was one case of acute occlusion with no long-term sequelae.

CONCLUSIONS

Intravascular ultrasound does not significantly accelerate atherosclerosis in native coronary arteries and can be used safely to assess progression/regression in clinical trials.

The link between IFN-gamma and allograft arteriopathy: is the answer NO?

Vascularized organ transplants often fail because of smooth muscle cell migration and proliferation in the intima of graft arteries, leading to progressive lumenal narrowing and resultant ischemic damage. Graft arterial disease is caused by IFN-gamma secreted by alloreactive T cells. New evidence indicates that IFN-gamma dysregulates expression of the enzymes eNOS and iNOS in graft-infiltrating leukocytes. Dysregulated NO synthase expression occurs prior to and is causally linked to intimal smooth muscle cell accumulation.

The transplant recipient for nontransplant surgery

The transplant recipient has traded a life-threatening illness for a chronically immunosuppressed state. Subsequent anesthetic management for non-transplant surgical procedures may be challenging. The anesthesia provider must be aware of the degree of post-transplant organ dysfunction and alter anesthesia techniques accordingly. This article reviews the anesthetic concerns for patients who have undergone a variety of organ transplants.

Superoxide Dismutase Mimetic M40401 Reduces Ischemia-Reperfusion Injury and Graft Coronary Artery Disease in Rodent Cardiac Allografts

BACKGROUND

The oxidative stress associated with ischemia-reperfusion (I/R) of cardiac allografts leads to production of injurious cytokines and expression of proinflammatory adhesion molecules. This is one of the most important alloantigen-independent factors associated with graft coronary artery disease (GCAD). M40401 is a newly developed cell permeable superoxide dismutase mimetic, which has been shown to scavenge superoxide anion with highly specific and enhanced catalytic activity. We hypothesized that M40401 would exert a protective effect in I/R injury of cardiac allografts and ameliorate the progression of GCAD.

METHODS

Recipient ACI rats were pretreated with M40401 or vehicle control. PVG donor hearts were heterotopically transplanted into the abdomen of ACI recipients. Cardiac allografts were analyzed for adhesion molecule mRNA expression and tumor necrosis factor-alpha expression after 4 hr of reperfusion. Neutrophil infiltration was detected by myeloperoxidase activity. Intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and endothelial leukocyte adhesion molecule-1 mRNA were detected by reverse-transcriptase polymerase chain reaction. Immunohistochemical analysis of adhesion molecule expression was also performed. Additional grafts were procured 90 days after transplantation and assessed for the development of GCAD by computer-assisted image analysis.

RESULTS

In the M40401-treated group, adhesion molecule expression was significantly less than in the vehicle control group. Treated grafts also had lower myeloperoxidase activity and tumor necrosis factor-alpha concentration compared with controls. Neointimal proliferation and intima to media ratios in M40401-treated allografts were significantly decreased compared with controls.

CONCLUSIONS

Selective removal of superoxide anion by M40401 results in inhibition of I/R injury. Furthermore, M40401 treatment decreases the development of oxidative stress-associated GCAD. This treatment strategy may have broad cardioprotective applications for all cardiac operations in addition to cardiac transplantation.

PDGF receptor kinase inhibitors for the treatment of PDGF driven diseases

PDGF and its receptors are involved in a variety of diseases: cancers, atherosclerosis, balloon injury induced restenosis, pulmonary fibrosis and more. In all cases enhanced signaling of the receptor is the hallmark. In some cases, like chronic monomyelocytic leukemia (CMML), the persistent PDGFR signaling is essential for the survival of the cancer cell. These findings induced the research community as well as the pharmaceutical industry to develop agents that block PDGFR signaling. The possible utilization of PDGFR kinase inhibitors as anti-restenosis agents is likely to move ahead of the utilization of these agents to treat human malignancies.

EFFECTS OF AGI-1096, A NOVEL ANTIOXIDANT COMPOUND WITH ANTI-INFLAMMATORY AND ANTIPROLIFERATIVE PROPERTIES, ON RODENT ALLOGRAFT ARTERIOSCLEROSIS

BACKGROUND

AGI-1096 is a novel phenolic intracellular antioxidant with anti-inflammatory and antiproliferative properties. In vitro, AGI-1096 inhibited the inducible expression of vascular cell adhesion molecule (VCAM)-1, E-selectin, and monocyte chemoattractant protein (MCP)-1 in endothelial cells and tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta secretion from lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells. It also inhibited serum-stimulated proliferation of aortic smooth-muscle cells. In vivo, AGI-1096 demonstrated anti-inflammatory properties in a murine delayed-type hypersensitivity model. Given these antioxidant, anti-inflammatory and antiproliferative properties, we reasoned that AGI-1096 may be able to prevent chronic allograft arteriosclerosis. This hypothesis was tested in a rodent aortic transplantation model.

METHODS

Donor descending aortas from August-Copenhagen-Irish rats were heterotopically transplanted into Lewis rat abdomens in end-to-end fashion. Animals were assigned to six groups as follows: AGI-1096 0 mg/kg per day (vehicle, n = 10), 10 mg/kg per day (n = 10), 20 mg/kg per day (n = 10), 40 mg/kg per day (n = 10), positive control (cyclosporine A 10 mg/kg per day by oral gavage, n = 10), and isograft negative control (Lewis-to-Lewis, n = 5). AGI-1096 was administrated subcutaneously to recipient animals three days before the surgery and for 90 days thereafter. On day 90, the paraffin-embedded allograft sections were stained with Elastin-van Gieson's stain, and the intima/media (I/M) ratio and luminal narrowing (1%LN) was assessed by digital morphometry.

RESULTS

AGI-1096 demonstrated dose-dependent lowering of the I/M ratio and %LN when compared with vehicle controls.

CONCLUSION

This is the first study to show that treatment of allograft recipients with AGI-1096 decreases the incidence of transplant arteriosclerosis. These data suggest that AGI-1096 may be a promising new therapeutic agent for use in clinical transplantation.

Angiotensin II receptors from peritransplantation through first-year post-transplantation and the risk of transplant coronary artery disease

OBJECTIVES

We evaluated whether the angiotensin II (Ang II) receptors from perioperation through one-year post-transplantation predict the transplant coronary artery disease (TCAD) progression.

BACKGROUND

The role of Ang II receptors (type 1: AT(1)R; type 2: AT(2)R) in TCAD is uncertain.

METHODS

We investigated 28 heart donors and the corresponding recipients. The levels of AT(1)R and AT(2)R messenger ribonucleic acid (mRNA) were examined in lymphocytes from the donor spleen and in the donor heart at one-week and one-year posttransplantation to determine their association with the progression of TCAD, measured as changes in maximal intimal thickness (CMIT) and plaque volume (CPV) by intravascular ultrasound (IVUS) examinations.

RESULTS

The AT(1)R mRNA in lymphocytes from the donor spleen (CMIT: r = 0.73, p < 0.0001; CPV: r = 0.69, p < 0.0001) and in the donor hearts at one-week (CMIT: r = 0.52, p = 0.005; CPV: r = 0.56, p = 0.002) and at one-year (CMIT: r = 0.63, p < 0.0001; CPV: r = 0.43, p = 0.004) post-transplantation along with AT(2)R mRNA in the donor hearts at one-year post-transplantation (CMIT: r = 0.3, p < 0.0001; CPV: r = 0.53, p = 0.009) were univariate predictors, whereas AT(1)R mRNA in lymphocytes and in the donor hearts at one-year post-transplantation proved to be multivariate predictors of the progression of TCAD.

CONCLUSIONS

These data suggest a role for Ang II receptors in the pathogenesis of TCAD and support a novel concept that TCAD may have its origin in the donor per se and may be modulated by the recipient's inherent biological factors.

Transplant Immunology

Since the early days of transplantation, it has been known that the immune system is the major barrier to long-term graft survival. Due to the unique “fingerprint” of different individuals’ cells, donor organs are detected as foreign, invasivematerial by the recipient’s immunesystem and, subsequently, attacked and rejected. The difficulty that has continuously faced the transplant community is the multifaceted nature of the immune response and halting the numerous pathways of immune stimulation. The ultimate goal of all transplant research is graft acceptance, also known as tolerance, without the use of long-term immunosuppressant medication. Various reviews of the different facets of transplant rejection exist. The following summary will attempt to outline the major known pathways involved in organ recognition and acute rejection.

Benefits of cardiac resynchronization therapy in outpatients with indicators for heart transplantation

BACKGROUND

Despite several new advances in the treatment of end-stage congestive heart failure (CHF) the number of patients moving onto the heart transplant list continues to rise. Recently, cardiac resynchronization therapy (CRT) has become a Food and Drug Administration (FDA)-approved therapy for advanced CHF. Currently, there are no available data on CRT in cardiac transplant candidates.

METHODS

To determine the effects of CRT on potential transplant candidates we retrospectively reviewed patients (n = 34) enrolled in resynchronization trials at our center who met accepted criteria for transplantation. Ventricular function, oxygen uptake and New York Heart Association (NYHA) class were compared at baseline and after 6 months of active therapy for each patient.

RESULTS

CRT reduced QRS duration from 178 +/- 29 to 143 +/- 17 msec (p < 0.0001) and NYHA class from 3.1 +/- 0.3 to 1.8 +/- 0.7 (p < 0.0001). Ejection fraction (EF) increased from 18.4 +/- 5.1 to 25.1 +/- 8.4% (p < 0.0001) and maximum VO(2) increased from 11.9 +/- 1.8 to 15.3 +/- 3 ml/kg/min (p < 0.0001). Only 2 of the initial 34 patients still met the criteria for transplantation at 6 months.

CONCLUSIONS

CRT improves ventricular function, oxygen uptake and NYHA class in ambulatory patients who have a QRS of >130 msec and might be considered candidates for cardiac transplantation. Transplantation can be prevented or deferred in the majority of patients. Outpatients with chronic CHF and a widened QRS should be evaluated for CRT before being listed for cardiac transplantation.

Non-invasive detection of coronary artery disease by dobutamine-stress echocardiography in children after heart transplantation

BACKGROUND

Coronary vasculopathy is the main cause of cardiac graft failure. Because yearly coronary angiography is invasive in children, a non-invasive method for detecting graft vasculopathy is needed. The aim of this study was to test dobutamine-stress echocardiography in a pediatric population to determine its feasibility, safety and reliability in the detection of graft coronary artery disease.

METHODS

Eighteen patients, aged 2 days to 16.8 years at transplantation (mean 8.4 years), underwent 44 dobutamine-stress echocardiography (DSE) exams, at a follow-up of 1.1 to 11.8 years (mean 5.1 years). Selective coronary angiography was performed for comparison. Echocardiographic recordings were obtained in 4 standard views of the left ventricle and measurements carried out within the frames of a 16-segment model. Segmental scores of contractility were obtained for each segment and a total segmental contractility index was calculated at each stage.

RESULTS

All patients reached the maximum dose stage. Maximum heart rate was 57% to 90% of predicted maximum. Maximum systolic blood pressure reached 190 mmHg. Segmental scores were normal in 37 and abnormal in 7 cases. Echographic results were concordant with angiography in 82% and discordant in 18% of the cases (4 negative DSEs with minor angiographic lesions, 2 positive DSEs with normal angiography), but there was no significant angiographic lesion with normal DSE.

CONCLUSIONS

DSE is a safe and highly feasible non-invasive technique in transplanted children. A normal DSE study successfully predicts the absence of significant coronary artery disease in the post-transplant population.

Sirolimus therapy in cardiac transplantation

Rapamycin powerfully inhibits the progression of antigen-activated T cells through the cell cycle. In animal heart transplantation models, rapamycin therapy has been associated with profound immunosuppressive effects on host humoral and cellular responses. In consequence, further studies have been conducted to evaluate the efficiency of rapamycin in preventing acute heart allograft rejection, treating refractory acute heart allograft rejection, inducing transplantation tolerance, and preventing and treating transplant coronary artery disease. The results of these studies indicated that rapamycin can effectively prevent acute graft rejection and inhibit refractory acute graft rejection in heart transplant recipients by exerting potent immunosuppressive and antiproliferative effects without adversely affecting renal function. This supports the use of rapamycin therapy in heart transplant recipients, especially in those with renal dysfunction, for whom treatment with calcineurin inhibitors is contraindicated. Rapamycin may also halt and even reverse the progression of cardiac allograft vasculopathy, which warrants further clinical trials in humans. Finally, rapamycin may be able to induce transplantation tolerance, thus making it one of the most promising modalities for improving the long-term survival of heart transplant recipients.

Upregulation of PAI-1 is mediated through TGF-beta/Smad pathway in transplant arteriopathy

BACKGROUND

Plasminogen activator inhibitor type 1 (PAI-1) is the primary physiologic inhibitor of plasminogen activator in vivo. Increased PAI-1 expression is associated with arteriosclerosis. Transforming growth factor-beta (TGF-beta) induces PAI-1 production via Smads.

METHODS

In vivo, TGF-beta receptors (TbetaRs), Smad2, Smad3, and Smad4, PAI-1, and Smad2 phosphorylation were examined by immunohistochemistry in 3 native aortas, 14 rat aortic syngrafts, and 19 allografts collected at 15, 30, and 45 days post-transplantation. In vitro, phosphorylation of Smad2 and induction of PAI-1 mRNA in human aortic smooth muscle cells (SMCs) in response to TGF-beta treatment were detected by Western blot and by TaqMan real-time RT-PCR, respectively.

RESULTS

Immunohistochemical staining revealed that vascular parenchymal cells contained TbetaRI, TbetaRII, Smad2, Smad3, and Smad4, known signaling transducers for TGF-beta/Smad pathway, in all samples. Intense staining for phospho-Smad2 was observed in 94% of endothelial cells (ECs), 86% of intimal cells, 27% of medial SMCs, and 38% of adventitial cells at all 3 time points in all aortic allografts, but only in 5% of ECs in syngrafts. PAI-1 immunoreactivity was detected in similar number of cells, and from consecutive sections, phospho-Smad2 colocalized with PAI-1, in the aortic allografts. Low basal level PAI-1 expression was observed in aortic syngrafts and native vessels. Smad2 phosphorylation and time-dependent PAI-1 induction were detected in cultured SMCs upon TGF-beta treatment.

CONCLUSIONS

Phospho-Smad2 staining in aortic allografts indicates the activation of TGF-beta signaling in allo-transplantation; and co-localization of PAI-1 and phospho-Smad2 suggests that PAI-1 upregulation is mediated mainly by TGF-beta/Smad pathway in aortic allografts.

Should moderate acute rejection of a cardiac transplant graft be treated?

Histologically proven, moderate acute rejection after orthotopic heart transplantation (OHT) is commonly treated with intravenous steroids. This regimen may result in severe metabolic and infectious side-effects. The purpose of this study was to assess and compare outcomes in treated (T) versus not treated (N-T) biopsy proven 3A rejection episodes in cardiac transplant recipients.

METHODS

A retrospective analysis was conducted to identify all biopsy proven 3A rejection episodes that occurred over the time period 1995-2000 in patients (patients) >or= 6 months after OHT (n=48 episodes in 35 patients). Of the 48 episodes, 19 were N-T and 29 were T. Decision to treat 3A rejection was based on time after transplant, haemodynamic and/or clinical compromise and left ventricular (LV) dysfunction measured by 2D echo. Most N-T episodes received an increase in background immunotherapy.

RESULTS

Time from transplant to index 3A episode in N-T patients was 4.2 versus 2.7 yr for the T patients (p=0.06). There were no differences seen between T and N-T groups for the first and second post-3A biopsy results or LV function post-3A. Presence of coronary disease or death were not different between groups. Of the 29 patients with T episodes, no differences in outcomes (death, first and second post-3A biopsy score, coronary disease, myocardial infarction, or LV function) were seen based on use of treatment with intravenous versus oral steroid.

CONCLUSION

In patients more than 6 month after OHT, there were no differences in outcomes (ongoing rejection or LV function) between N-T episodes of 3A rejection and T episodes. In T patients the use of oral steroids was equally as effective for treatment of 3A episodes as intravenous steroids.

Heart transplantation: a thirty-year perspective

Heart transplantation has evolved over the past 30 years into a mainstay of therapy for heart failure patients. As the surgical technique and basic immunology were defined, heart transplantation became a real therapeutic option. Over the next few decades, thoracic transplant teams at Stanford University and other institutions refined this mode of therapy. This review addresses the history, current surgical technique, recipient and donor selection, postoperative care, immunosuppression, short- and long-term complications, and clinical outcomes associated with this procedure.

Correlation of chlamydia pneumoniae infection and severity of accelerated graft arteriosclerosis after cardiac transplantation

BACKGROUND

Chlamydia pneumoniae has been associated with atherosclerosis, although its role in the process is not clearly defined. Heart transplant recipients are known to have high titers of antibodies to C. pneumoniae, and the organism has been recovered from the coronary arteries of both transplant recipients and donors. This study evaluated association between C. pneumoniae infection and accelerated graft arteriosclerosis (AGA), also known as cardiac allograft vasculopathy (CAV), after cardiac transplantation.

METHODS

A case-control study was performed with 54 heart transplant recipients at the Johns Hopkins Hospital. Severe cases had >50% luminal narrowing on cardiac catheterization, mild cases <50% narrowing, and controls were free of arteriosclerotic disease. Blood specimens were examined for C. pneumoniae serology and DNA detection by polymerase chain reaction (PCR) assays.

RESULTS

For every twofold increase in geometric mean C. pneumoniae immunoglobulin (Ig)G titer, the odds ratio for severe AGA versus controls was 3.13 (P=0.03) and for mild AGA versus control patients was 1.61 (P=0.45). On Kaplan-Meier survival analysis there was a nonsignificant trend toward faster development of CAV in patients with higher C. pneumoniae antibody titers. Overall, 29% of heart transplant patients evaluated had evidence of circulating C. pneumoniae DNA by PCR, without a statistical difference between groups.

CONCLUSIONS

C. pneumoniae IgG titer correlates with severity of allograft arteriosclerosis after cardiac transplantation. Circulating C. pneumoniae DNA is detectable by PCR in up to 30% of cardiac transplant recipients, but this does not correlate with severity of allograft vasculopathy.