Persistent mild lesions in coronary angiography predict poor long-term survival of heart transplant recipients

Validation of multiparametric rubidium-82 PET myocardial blood flow quantification for cardiac allograft vasculopathy surveillance

BACKGROUND

We previously demonstrated high diagnostic accuracy of Rubidium-82 positron emission tomography (PET) myocardial blood flow (MBF) quantification for CAV. The purpose of this study was to validate multiparametric PET detection of CAV by combined rate-pressure-product-corrected myocardial flow reserve (cMFR), stress MBF, and coronary vascular resistance (CVR) assessment.

METHODS AND RESULTS

Diagnostic CAV cut-offs of cMFR < 2.9, stress MBF < 2.3, CVR > 55 determined in a previous study (derivation) were assessed in heart transplant recipients referred for coronary angiography and intravascular ultrasound (IVUS) (validation). CAV was defined as International Society of Heart and Lung Transplantation CAV1-3 on angiography; and maximal intimal thickness ≥ 0.5 mm on IVUS. Eighty patients (derivation n = 40, validation n = 40) were included: 80% male, mean age 54±14 years, 4.5±5.6 years post transplant. The prevalence of CAV was 44% on angiography and 78% on IVUS. Combined PET cMFR < 2.9, stress MBF < 2.3, CVR > 55 CAV assessment yielded high 88% (specificity 75%) and 83% (specificity 40%) sensitivity for ≥ 1 abnormal parameter and high 88% (sensitivity 59%) and 90% (sensitivity 43%) specificity for 3 abnormal parameters, in the derivation and validation cohorts, respectively.

CONCLUSION

We validate the diagnostic accuracy of multiparametric PET flow quantification by cMFR, stress MBF, and CVR for CAV.

Association between routine measures of graft function and mortality in heart transplant recipients

OBJECTIVE

To date, long-term graft dysfunction, an important cause of death after heart transplantation, has been defined as a left ventricular ejection fraction (LVEF) of ≤40% or right atrial pressure (RAP) of ≥15 mm Hg. Empirical associations between measures of cardiac function and mortality post-transplant remain, however, unestablished.

METHODS

We conducted a retrospective two-centre cohort study of consecutive adults who underwent heart transplant between 2002 and 2017. We evaluated the association between LVEF and RAP and mortality, including rejection and cardiac allograft vasculopathy as additional time-dependent covariates using Cox proportional hazard models. We applied restricted cubic splines to both LVEF and RAP.

RESULTS

Of 590 eligible heart transplant recipients, of whom 72% were male with a mean age of 49 years, 410 received their transplant at Toronto General Hospital and 180 at Rigshospitalet. We observed a 5% absolute risk increase for 1-year mortality, from 11% to 16%, when the LVEF dropped to 53% (HR 1.71 for LVEF of 53% compared with 60%, 95% CI 1.36 to 2.14) or when the RAP increased to 12 mm Hg (HR 1.49 for RAP of 12 mm Hg compared with 5 mm Hg, 95% CI 1.04 to 2.13).

CONCLUSION

In this study, we observed that small changes in graft function at any time post-transplant are associated with an increased mortality. Our results suggest that the current definition of graft dysfunction may underestimate patient risk of adverse outcomes.

Visfatin serum concentration is associated with cardiac allograft vasculopathy in heart transplant recipients

Cardiac allograft vasculopathy (CAV) still is one of the most important limiting factors of long-term survival following heart transplant (HT). This study aimed to investigate the association between proinflammatory adipokine-visfatin and the incidence of CAV in HT recipients. After HT, 182 patients who had a follow-up visit at the Transplantation Clinic between 2016 and 2017 were analyzed. The median age was 60.5 years, and 76.4% were men. The incidence of CAV was 54.9%. According to the multivariable proportional hazard regression analysis, visfatin level (1.795 [1.539-2.094]; P < .001) was significantly associated with CAV, and statin use was protective against CAV (0.504 [0.32-0.793]; P = .003). The area under the receiver operating characteristic curve indicated an excellent discriminatory power of visfatin (0.9548 [0.9281-0.9816]) for CAV detection. The cutoff value of 5.42 ng/mL for visfatin yielded a sensitivity of 89% and specificity of 91%. This is the first study to demonstrate that visfatin serum concentrations are independently associated with the incidence of CAV in HT recipients. Visfatin allows for simple and cheap detection of CAV given its excellent discriminatory ability and high sensitivity and specificity. In addition, we have found an independent association between the statin use and a lower risk of CAV.

Cardiac allograft vasculopathy in Dutch heart transplant recipients

BACKGROUND

Cardiac allograft vasculopathy (CAV) is a multifactorial disease and a major cause of graft failure after heart transplantation. However, the impact of CAV may vary according to the definition and the regional differences in transplantation settings.

OBJECTIVES

We sought to assess CAV prevalence, predictors and prognosis in Dutch heart transplant recipients based on coronary angiography, following the 2010 standard nomenclature of the International Society for Heart and Lung Transplantation.

METHODS

Patients ≥18 years who underwent heart transplantation at our centre with at least one coronary angiography during follow-up were included in the analysis. Clinical variables were collected prospectively.

RESULTS

Among 495 analysed recipients, there were 238 (48 %) with CAV. The prevalence of CAV was 18, 47 and 70 % at 4, 12 and 20 years, respectively. In the multivariable proportional hazards regression analysis, only male donor gender and increasing donor age were significantly associated with the risk of CAV. The long-term prognosis of the patients with CAV at fourth-year angiography was significantly worse as compared with that of CAV-free patients, independently of the severity of CAV (p < 0.001).

CONCLUSION

The prevalence of CAV increased gradually over time, with a similar trend as in other registries. Post-transplant survival is decreased in patients with any degree of early CAV, indicating that management strategies should start with donor selection and preventive measures immediately after transplantation.

Latest developments in heart transplantation: a review

PURPOSE

Heart transplantation (HT) remains the treatment of choice for advanced heart failure despite improvements in medical therapy and mechanical circulatory support. Significant developments have occurred in the field of HT over the past year, in particular the successful transplantation of donor hearts after circulatory determination of death. The purpose of this article was to review developments in HT published in 2014 and 2015.

METHODS

Selected articles found using a MEDLINE search of the key term heart transplant were reviewed.

FINDINGS

The year has seen improvements in the attenuation of ischemia and reperfusion injury, patient selection, immunosuppression, imaging of the transplanted heart, and donor organ preservation that hold promise for increasing the number of transplantations and improving outcomes in HT recipients. Advances in the detection and attenuation of cardiac rejection and allograft vasculopathy are highlighted.

IMPLICATIONS

A number of significant advances over the past year hold promise for tangible improvements in outcomes in the field of HT.

Terminal heart failure: who should be transplanted and who should have mechanical circulatory support?

PURPOSE OF REVIEW

Permanent long-term mechanical circulatory support (MCS) is currently reserved for patients who are transplant ineligible. In light of improved outcomes with current continuous flow devices, increased interest has focused on the potential extension of MCS therapy to ambulatory advanced heart failure patients and as an alternative to cardiac transplantation.

RECENT FINDINGS

Average 1-year and 2-year survival with heart transplantation is about 85 and 80%, and with MCS therapy, it is 85 and 70% (with censoring at transplant). Specific subsets of destination therapy patients enjoy survival out to 2 years, which is comparable with transplant survival. Risk factor analyses identify similar risk profiles for each therapy. Life satisfaction after each is highly dependent on the frequency and severity of adverse events, which are quite different for these interventions. Patients with long expected waiting times will likely be the initial group for triage off the transplant wait list to MCS therapy.

SUMMARY

MCS has progressively improved and may become a reasonable alternative to transplantation for highly selected patients with long expected waiting time. More routine extension of MCS therapy to the transplant population awaits further reduction of major adverse events, miniaturized devices, and less invasive implant techniques.