Low clinical utility of routine angiographic surveillance in the detection and management of cardiac allograft vasculopathy in transplant recipients

Cholesterol efflux capacity of high-density lipoprotein correlates with survival and allograft vasculopathy in cardiac transplant recipients

BACKGROUND

Cardiac allograft vasculopathy (CAV) is a major cause of mortality after cardiac transplantation. High-density lipoprotein (HDL) cholesterol efflux capacity (CEC) is inversely associated with coronary artery disease. In 2 independent studies, we tested the hypothesis that reduced CEC is associated with mortality and disease progression in CAV.

METHODS

We tested the relationship between CEC and survival in a cohort of patients with CAV (n = 35). To determine whether reduced CEC is associated with CAV progression, we utilized samples from the Clinical Trials in Organ Transplantation 05 (CTOT05) study to determine the association between CEC and CAV progression and status at 1 year (n = 81), as assessed by average change in maximal intimal thickness (MIT) on intravascular ultrasound.

RESULTS

Multivariable Cox proportional hazard models demonstrated that higher levels of CEC were associated with improved survival (hazard ratio 0.26, 95% confidence interval 0.11 to 0.63) per standard deviation CEC, p = 0.002). Patients who developed CAV had reduced CEC at baseline and 1-year post-transplant. We observed a significant association between pre-transplant CEC and the average change in MIT, particularly among patients who developed CAV at 1 year (β = -0.59, p = 0.02, R² = 0.35).

CONCLUSION

Reduced CEC is associated with disease progression and mortality in CAV patients. These findings suggest the hypothesis that interventions to increase CEC may be useful in cardiac transplant patients for prevention or treatment of CAV.

Long-term outcome after heart transplantation predicted by quantitative myocardial blush grade in coronary angiography

The purpose of our study was to investigate whether the quantification of myocardial blush grade (MBG) during surveillance coronary angiography can predict long-term outcome after heart transplantation (HT). In 105 HT recipients who underwent cardiac catheterization, cardiac allograft vasculopathy (CAV) was assessed visually using the ISHLT grading scale (prospective cohort study). MBG was quantified by dividing the plateau of contrast agent gray-level intensity (G(max)) by the time-to-peak intensity (T(max)). In a subgroup (n = 72), myocardial perfusion index by cardiac magnetic resonance imaging (CMR) was assessed. During a mean follow-up duration of 2.7 (standard deviation [SD] 1.0) years, 26 patients experienced cardiac events, including 7 with cardiac death and 19 who underwent coronary revascularization. G(max)/T(max) was related to CAV by ISHLT criteria and to subsequent cardiac events. By univariate analysis, patient age, organ age, CAV, MBG and myocardial perfusion index by CMR were all predictive for cardiac events. Multivariable analysis demonstrated that G(max)/T(max) provided the most robust prediction of cardiac death (hazard ratio [HR] = 0.2, 95% confidence interval [CI] = 0.06-0.64, p < 0.01) and cardiac events (HR = 0.52, 95% CI = 0.32-0.84, p < 0.01), beyond clinical parameters and the presence of CAV. G(max)/T(max) is a valuable surrogate parameter of microvascular integrity, which is associated with cardiac death and revascularization procedures after HT.

Evaluation of coronary allograft vasculopathy using multi-detector row computed tomography: a systematic review

Coronary allograft vasculopathy (CAV) is a significant cause of morbidity and mortality after cardiac transplantation and requires frequent surveillance with catheter-based coronary angiography (CCA). Multi-detector row computed tomography (MDCT) has been shown to be effective in assessing atherosclerosis in native coronary arteries. This article systematically reviews the literature to determine the accuracy of MDCT in CAV assessment. An English-language literature search was performed using EMBASE, OVID, PubMed, and Cochrane Library databases. Studies that directly compared MDCT with CCA and/or IVUS for the detection of coronary artery stenosis or significant intimal thickening in cardiac transplant patients were analyzed. Data were pooled to obtain weighted sensitivities, specificities, and diagnostic accuracies. Negative and positive predictive values (NPV/PPV) were calculated. A total of seven studies with a sum of 272 patients were included in this review. There were three studies examining 16-slice MDCT and four studies looking at 64-slice MDCT in CAV. Using per-segment analysis, MDCT assessed between 91% and 96% of all coronary segments when evaluating for stenosis. Pooled estimates for sensitivity and specificity for MDCT ranged from 82% to 89% and 89% to 99%, respectively, while NPV was 99%. Per-patient analysis revealed a sensitivity of 87-100% and NPV of 96-100%. PPV was less than 50% for 64-slice MDCT in both per-segment and per-patient analysis. When compared with IVUS, MDCT had a sensitivity of 74-96% and specificity of 88-92% in assessment of intimal thickening. NPV and PPV were 80-81% and 84-98%, respectively. The high sensitivity and NPV of MDCT suggest that it may be a useful, noninvasive screening tool to rule out CAV.

Cardiovascular magnetic resonance in the evaluation of heart failure: a luxury or a need?

Heart failure is a common syndrome with multiple causes. Cardiovascular magnetic resonance (CMR), using the available range of technique, is establishing itself as the gold standard noninvasive test for determining the underlying causes, and adding prognostic value, guiding therapy. Progress is continuing and rapid with promising new techniques such as diffuse fibrosis assessment. This article discusses the diverse roles of CMR in heart failure.

Heart transplant patient outcomes: 5-year mean follow-up by coronary computed tomography angiography

BACKGROUNDS

We evaluate the feasibility and safety of coronary computed tomography angiography (CCTA) as the first-line investigation in heart transplant patients and the rate of coronary allograft vasculopathy detected using CCTA.

METHODS

From September 2003 to June 2009, we prospectively included 65 heart transplant recipients, retaining 62 who underwent yearly CCTA for coronary allograft vasculopathy detection (261 CCTAs). We used 16-slice, 64-slice, and 2×64-slice CT machines. Patients with coronary artery stenosis by CCTA had a confirmation and a further follow-up exclusively by conventional coronary angiography (CCA).

RESULTS

No major coronary events occurred during the study. Of the 62 baseline CCTAs, 37 (60%) were normal, 18 (29%) showed wall thickening, and 7 (11%) known significant stenosis, confirmed by CCA. The mean follow-up duration was 5 years. At the last follow-up, 26 (70%) patients with normal baseline findings remained normal, 9 (24%) had wall thickening, and 2 (6%) significant stenoses. Time to stenosis was consistently greater than 3 years. Of the 18 patients with initially wall thickening, 14 (78%) had wall thickening and 4 (22%) significant stenosis at last follow-up. The mean interval without any coronary lesion was 9.46±3.98 years. The mean interval without de novo significant stenosis was 10.31±4 years.

CONCLUSIONS

CCTA seems to be a safe noninvasive tool for monitoring heart transplant patients, and thus obviating the need for CCA. In patients with normal baseline CCTA, a 2-year interval between CCTAs may be safe.

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.

The Emerging Role of Multi-Detector Computed Tomography in Heart Failure

BACKGROUND

Recent advances in cardiac multi-detector computed tomography (MDCT) technology now permits entire coronary tree evaluation in a single breath hold with submillimeter slice collimation and improved temporal resolution.

METHODS AND RESULTS

Besides excellent correlation with invasive angiogram for the detection of significant coronary occlusion, MDCT also provides reliable and reproducible data regarding various other cardiac anatomic and functional parameters that are pertinent to heart failure patients. These include left ventricular measurement (eg, ejection fraction, regional wall motion, dimensions, volumes), pulmonary vein anatomy and drainage, right ventricular function, and cardiac venous system, among many others. However, there are radiogenic and nonradiogenic risks associated with MDCT that should be considered before scanning the patients.

CONCLUSIONS

This review summarizes the existing literature of the various cardiac MDCT applications pertinent to heart failure patients.

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.

Transplant coronary artery disease: Incidence, progression and interventional revascularization

BACKGROUND

Allograft coronary artery disease (CAD) remains the main factor responsible for late graft loss. This analysis describes data on incidence and progression of allograft CAD at our institute, as well as our experience with coronary interventions in heart transplant recipients.

METHODS

Angiographic results of cardiac transplant patients undergoing coronary angiography were prospectively selected and analyzed. Angiographic outcome at follow-up were assessed for all coronary revascularizations in denovo lesions.

RESULTS

Four hundred thirty-two coronary angiographies were performed in a total of 246 patients. Seventy-six patients (30.9%) showed angiographic evidence of CAD with %DS>50%, of which 48 patients revealed significant stenosis with %DS>70% (19.5%). Within the first 5 years after the transplantation, 10.1% show angiographic signs of a CAD; at the time of 10.1 years, 50% of all heart transplant patients have developed a CAD. Once a CAD with %DS between 50% and 60% has evolved, the disease shows fast progression. Coronary intervention was performed in 28 vessels at an average time of 9.5 years after heart transplantation. Follow-up angiography was available for 27 vessels (1 death before re-angiography) within a mean follow-up period of 19.3 months. Binary restenosis was found in 7 out of 27 vessels (25.9%). Comparison of the occurrence of total occlusion in vessels with %DS>70% which were not revascularized to the occurrence of MACE after successful revascularization revealed better long term results in the group of patients with coronary intervention (p=0.04).

CONCLUSION

Whereas coronary artery disease is found in rare cases within the first 5 years after heart transplantation, the incidence grows in exponential manner after this period. Mid-term follow-up after coronary intervention exhibit restenosis-rates which are similar to the ones of other high risk patients. Comparison of coronary intervention versus conservative treatment in vessels with %DS>70% show significant better mid-term outcome in the interventional group.

Coronary stenosis detection by 16-slice computed tomography in heart transplant patients: comparison with conventional angiography and impact on clinical management

OBJECTIVES

We sought to find a non-invasive alternative to conventional coronary angiography (CCA) for serial detection and follow-up of coronary stenosis due to cardiac allograft vasculopathy in heart transplant patients.

BACKGROUND

Cardiac allograft vasculopathy is the main factor limiting long-term success of heart transplantation. It is usually detected by CCA. Multislice computed tomography (MSCT) coronary angiography has recently proven effective for the diagnosis of coronary stenosis in non-transplant patients.

METHODS

Fifty-three consecutive heart transplant patients underwent MSCT within 24 h before or after their annual routine CCA. Only angiographic segments >1.5 mm were considered for analysis; the coronary arterial tree was divided into nine segments. Three patients were excluded because of technical failure.

RESULTS

Of the 450 angiographic coronary segments, 432 (96%) were evaluable by MSCT. Of the nine coronary stents in seven patients, only three, including one intrastent restenosis, were correctly evaluated by MSCT, and two intrastent restenoses were missed. Complete analysis of the coronary tree was possible for 44 (88%) of the 50 patients. For detection of coronary stenosis >50%, sensitivity was 83%, specificity 95%, positive predictive value 71%, negative predictive value 95%, and accuracy 93%. In the 22 patients with strictly normal MSCT, no stenosis was found by CCA.

CONCLUSIONS

Our study suggests the following guidelines already applied in our institution: 16-slice MSCT can replace CCA in de novo heart transplant patients and patients with strictly normal MSCT at follow-up. Significant wall or lumen changes observed on annual MSCT or stents require further investigation by CCA.

Diagnostic accuracy of coronary angiography and risk factors for post-heart-transplant cardiac allograft vasculopathy

Cardiac allograft vasculopathy (CAV) is a common cause of death after heart transplantation. Coronary angiography is used to monitor the progress of recipients. Diagnostic accuracy of angiography and risk factors for CAV have not been clearly established. Between August 1979 and January 2002, 566 1-year survivors of heart transplantation underwent 2168 angiograms and were classified as having no CAV (0% stenosis), mild-moderate CAV (up to 70% stenosis), or severe CAV (>70% stenosis). We used serial measurements of stenosis to estimate the diagnostic accuracy of angiography and to assess the following risk factors for CAV onset, progression, and survival: recipient and donor age and sex, preoperative ischemic heart disease (IHD), acute rejection rates, cytomegalovirus (CMV) infection, and serologic status. CAV was diagnosed by angiography in 248 of 556 (45%) 1-year survivors, with a mean onset time of 8.6 years. Patients spent a mean of 3.4 years with mild-moderate disease and 3.4 years with severe disease before death. Angiography specificity was 97.8%, and sensitivity was 79.3%. The following variables were found to significantly increase the risk of CAV onset: recipient age relative rate (95% confidence interval) 1.16 (1.01-1.34), donor age by 1.27 (1.13-1.43), male recipient by 2.00 (1.11-2.57), pretransplant IHD by 1.75 (1.30-2.36), cumulative rejection by 1.13 (1.05-1.21), and CMV infection by 1.42 (1.06-1.92). Acute rejection increased risk of death by 1.48 (1.19-1.85). Angiography is highly specific and moderately sensitive for diagnosis of CAV. Risk of CAV onset is related to donor age and recipient history of pretransplant IHD and is further increased by immune-related insults of acute rejection and CMV infection.

A comparison of intravascular ultrasound with coronary angiography for evaluation of transplant coronary disease in pediatric heart transplant recipients

BACKGROUND

The purpose of this study was to assess the sensitivity of coronary angiography versus intravascular ultrasound for detecting significant transplant coronary artery disease in children. We also examined associations between potential risk factors for transplant coronary artery disease and intravascular ultrasound findings, and evaluated the safety of intravascular ultrasound.

METHODS

All pediatric heart transplant patients who had intravascular ultrasound following routine coronary angiography were included. Transplant coronary artery disease was quantified by assigning Stanford classes and calculating intimal indices for intravascular ultrasound images. These findings were compared with qualitative coronary angiography findings. Risk factors for transplant coronary artery disease, cardiac events and complications were recorded.

RESULTS

Sixteen patients had 27 intravascular ultrasound procedures during the study period. All patients had evidence of transplant coronary artery disease at their latest intravascular ultrasound study. Of the patients whose most severely afflicted coronary artery underwent both imaging modalities at the latest study, 50% had significant transplant coronary artery disease (Stanford Class >/=II) by intravascular ultrasound and normal coronary angiography. A higher mean first-year biopsy score may be associated with significant transplant coronary artery disease by intravascular ultrasound, but a large number of patients will be required to determine this with statistical certainty. One major complication occurred early in the experience.

CONCLUSIONS

In children, intravascular ultrasound is more sensitive for detecting significant transplant coronary artery disease than coronary angiography, but may add cost, time and potential morbidity to screening protocols. Prospective, multicenter studies are needed to best utilize intravascular ultrasound in this patient population.

Percutaneous coronary intervention versus medical therapy for coronary allograft vasculopathy. One center's experience

BACKGROUND

Coronary allograft vasculopathy, a rapidly progressive form of atherosclerosis, remains the limiting factor in the long-term survival of heart transplant recipients. Some centers have attempted percutaneous coronary intervention to slow the disease process and thereby reduce mortality in these patients, but long-term follow-up data are scarce. We compared clinical outcomes in heart transplant recipients with coronary allograft vasculopathy who were treated either with percutaneous coronary intervention or with aggressive medical therapy alone.

METHODS

A retrospective analysis of all heart transplant recipients at our institution who underwent surveillance coronary angiography for coronary allograft vasculopathy between 1995 and 2000 was performed. Patients with coronary allograft vasculopathy were stratified according to whether they received medical therapy or percutaneous coronary intervention. Baseline demographics, results of re-vascularization procedures and outcomes were analyzed.

RESULTS

From 1995 to 2000, 301 patients underwent 602 coronary angiograms. Of the 79 patients who had angiographic evidence of coronary allograft vasculopathy, 53 were treated with aggressive medical therapy, while 26 underwent percutaneous coronary intervention in addition to aggressive medical therapy. At baseline, patients treated with aggressive medical therapy tended to be younger (54.6 +/- 13.8 years) than patients treated with percutaneous coronary intervention (62.6 +/- 7.6 years; p = 0.0079). Ejection fraction at time of diagnosis of coronary allograft vasculopathy was similar for both groups (medical therapy group, 44.4 +/- 13.4% vs percutaneous coronary intervention group, 47.2 +/- 12.7%; p = 0.38). In our cohort, heart transplant recipients with coronary allograft vasculopathy demonstrated greater mortality than heart transplant recipients without coronary allograft vasculopathy (p = 0.016). Patients who underwent percutaneous coronary intervention had a 60% re-stenosis rate at 6 months if they were treated with coronary angioplasty and an 18% re-stenosis rate if they received a coronary stent. Kaplan-Meier analysis showed no significant difference in survival in either treatment group at 1 year (80% for medical therapy group vs 95% for percutaneous coronary intervention group) or 3 years (68% for medical therapy group vs 79% for percutaneous coronary intervention group) after the angiographic diagnosis of coronary allograft vasculopathy.

CONCLUSION

In this non-randomized trial, heart transplant recipients with coronary allograft vasculopathy were less likely to survive than patients without it. In addition, we found no statistical difference in mortality in heart transplant recipients with coronary allograft vasculopathy, regardless of whether they received percutaneous coronary intervention or aggressive medical therapy alone.