Search

The aims of this study were to quantify preoperative myocardial fibrosis using late gadolinium enhancement (LGE), extracellular volume fraction (ECV%), and indexed extracellular volume (iECV) on cardiac magnetic resonance; determine whether this varies following surgery; and examine the impact on postoperative outcomes.Myocardial fibrosis complicates chronic severe primary mitral regurgitation and is associated with left ventricular dilatation and dysfunction. It is not known if this nonischemic fibrosis is reversible following surgery or if it affects ventricular remodeling and patient outcomes.A multicenter prospective study was conducted among 104 subjects with primary mitral regurgitation undergoing mitral valve repair. Cardiac magnetic resonance and cardiopulmonary exercise stress testing were performed preoperatively and ≥6 months after surgery. Symptoms were assessed using the Minnesota Living With Heart Failure Questionnaire.Mitral valve repair was performed for Class 2a indications in 65 patients and Class 1 indications in 39 patients. Ninety-three patients were followed up at 8.8 months (IQR: 7.4 months-10.6 months). Following surgery, there were significant reductions in both ECV% (from 27.4% to 26.6%; P = 0.027) and iECV (from 17.9 to 15.4 mL/mMitral valve surgery results in reductions in ECV% and iECV, which are surrogates of diffuse myocardial fibrosis, and preoperative iECV predicts the degree of postoperative remodeling irrespective of symptoms. (The Role of Myocardial Fibrosis in Degenerative Mitral Regurgitation; NCT02355418).

Background Myocardial fibrosis occurs in end-stage heart failure secondary to mitral regurgitation (MR), but it is not known whether this is present before onset of symptoms or myocardial dysfunction. This study aimed to characterise myocardial fibrosis in chronic severe primary MR on histology, compare this to tissue characterisation on cardiovascular magnetic resonance (CMR) imaging, and investigate associations with symptoms, left ventricular (LV) function, and exercise capacity. Methods Patients with class I or IIa indications for surgery underwent CMR and cardiopulmonary exercise testing. LV biopsies were taken at surgery and the extent of fibrosis was quantified on histology using collagen volume fraction (CVFmean) compared to autopsy controls without cardiac pathology. Results 120 consecutive patients (64 ± 13 years; 71% male) were recruited; 105 patients underwent MV repair while 15 chose conservative management. LV biopsies were obtained in 86 patients (234 biopsy samples in total). MR patients had more fibrosis compared to 8 autopsy controls (median: 14.6% [interquartile range 7.4–20.3] vs. 3.3% [2.6–6.1], P mean 13.6% [6.3–18.8], P mean 15.7% [9.9–23.1] (P = 0.083). Fibrosis was patchy across biopsy sites (intraclass correlation 0.23, 95% CI 0.08–0.39, P = 0.001). No significant relationships were identified between CVFmean and CMR tissue characterisation [native T1, extracellular volume (ECV) or late gadolinium enhancement] or measures of LV function [LV ejection fraction (LVEF), global longitudinal strain (GLS)]. Although the range of ECV was small (27.3 ± 3.2%), ECV correlated with multiple measures of LV function (LVEF: Rho = − 0.22, P = 0.029, GLS: Rho = 0.29, P = 0.003), as well as NTproBNP (Rho = 0.54, P 2max: R = − 0.22, P = 0.030). Conclusions Patients with chronic primary MR have increased fibrosis before the onset of symptoms. Due to the patchy nature of fibrosis, CMR derived ECV may be a better marker of global myocardial status. Clinical trial registration Mitral FINDER study; Clinical Trials NCT02355418, Registered 4 February 2015, https://clinicaltrials.gov/ct2/show/NCT02355418

Cardiac transplantation is limited by donor availability and carries a considerable perioperative mortality in addition to continuing morbidity and mortality post-transplant. Some patients referred for transplantation may benefit from non-transplant cardiac surgery. This study assessed the results of non-transplant cardiac surgery in this high-risk group of patients over the 5-year period 1996-2001. Twenty-five such patients underwent conventional cardiac surgery and these were highly symptomatic, with angina and dyspnoea. All had impaired left ventricular function, 20 having left ventricular ejection fraction (LVEF)

The induction of donor-specific tolerance remains an important objective in transplantation to obviate the need for immunosuppression and prevent chronic rejection. Operational tolerance to cardiac allografts can certainly be induced in small animal models. Recent interest has focused on refining the tolerance induction regimens to minimize toxicity and on examining the mechanisms responsible for donor-specific unresponsiveness in these experimental systems. Particular progress has been made on strategies to block T-cell costimulation and on delivery of alloantigens via donor-specific transfusion or bone marrow infusion. Interactions between various forms of immunotherapy and conventional immunosuppression are being studied and there is early evidence of synergy, as well as data suggesting inhibition of tolerance induction by calcineurin inhibitors.