Outcomes of transcatheter mitral valve replacement for degenerated bioprostheses, failed annuloplasty rings, and mitral annular calcification.

Aims: We sought to evaluate the outcomes of transcatheter mitral valve replacement (TMVR) for patients with degenerated bioprostheses [valve-in-valve (ViV)], failed annuloplasty rings [valve-in-ring (ViR)], and severe mitral annular calcification [valve-in-mitral annular calcification (ViMAC)]. Methods and results: From the TMVR multicentre registry, procedural and clinical outcomes of ViV, ViR, and ViMAC were compared according to Mitral Valve Academic Research Consortium (MVARC) criteria. A total of 521 patients with mean Society of Thoracic Surgeons score of 9.0 ± 7.0% underwent TMVR (322 patients with ViV, 141 with ViR, and 58 with ViMAC). Trans-septal access and the Sapien valves were used in 39.5% and 90.0%, respectively. Overall technical success was excellent at 87.1%. However, left ventricular outflow tract obstruction occurred more frequently after ViMAC compared with ViR and ViV (39.7% vs. 5.0% vs. 2.2%; P < 0.001), whereas second valve implantation was more frequent in ViR compared with ViMAC and ViV (12.1% vs. 5.2% vs. 2.5%; P < 0.001). Accordingly, technical success rate was higher after ViV compared with ViR and ViMAC (94.4% vs. 80.9% vs. 62.1%; P < 0.001). Compared with ViMAC and ViV groups, ViR group had more frequent post-procedural mitral regurgitation ≥moderate (18.4% vs. 13.8% vs. 5.6%; P < 0.001) and subsequent paravalvular leak closure (7.8% vs. 0.0% vs. 2.2%; P = 0.006). All-cause mortality was higher after ViMAC compared with ViR and ViV at 30 days (34.5% vs. 9.9% vs. 6.2%; log-rank P < 0.001) and 1 year (62.8% vs. 30.6% vs. 14.0%; log-rank P < 0.001). On multivariable analysis, patients with failed annuloplasty rings and severe MAC were at increased risk of mortality after TMVR [ViR vs. ViV, hazard ratio (HR) 1.99, 95% confidence interval (CI) 1.27-3.12; P = 0.003; ViMAC vs. ViV, HR 5.29, 95% CI 3.29-8.51; P < 0.001]. Conclusion: The TMVR provided excellent outcomes for patients with degenerated bioprostheses despite high surgical risk. However, ViR and ViMAC were associated with higher rates of adverse events and mid-term mortality compared with ViV.

Valve-in-valve transcatheter aortic valve implantation with CoreValve/Evolut R© for degenerated small versus bigger bioprostheses.

OBJECTIVES: We present our single center experience with Medtronic CoreValve and Evolut R regarding procedural outcome and 3 years follow-up in patients with degenerated bioprostheses. METHODS: From 1645 patients who underwent transfemoral TAVI at our institution between February 2009 and December 2016, 37 patients with degenerated bioprosthesis were treated with Medtronic CoreValve/Evolut R. All data concerning baseline characteristic, procedural outcomes and follow-up were entered into a dedicated database. RESULTS: Mean age was 83.9 ± 4.4 years and patients showed an average logistic EuroSCORE of 33.2 ± 16.7%. Successful ViV deployment was achieved in all cases, a permanent pacemaker was implanted in 16.2%, no periinterventional stroke and no coronary obstruction occurred. Mortality at 30 days was 2.7%, at 1-year follow-up 5.7% and at three years 13.5%. Depending on bioprosthesis size <23 mm versus ≥23 mm echocardiographic mean gradients post implantation were significantly higher in the smaller bioprostheses, 22.8 mmHg ± 9.4 mmHg versus 15.1 ± 7.1, P = 0.013. CONCLUSION: ViV-TAVI with CoreValve/R is demonstrated to be safe and effective in terms of no coronary obstruction and very low mortality up to 3 years despite slightly higher mean transprosthetic gradients especially in very small bioprostheses.

Transcatheter Aortic Valve Implantation in Nonagenarians: Procedural Outcome and Mid-Term Results.

BACKGROUND: For nonagenarians with symptomatic severe aortic stenosis transcatheter aortic valve implantation (TAVI) has become a feasible therapeutic option. Therefore, the aim of this study was to evaluate the procedural outcomes and mid-term follow-up in this patient group and compare this to octogenarians. METHODS: From 1359 patients who underwent TAVI at our institution between March 2009 and February 2016, 82 patients were nonagenarians and 912 were octogenarians. In nonagenarians, mean age was 91.9±1.4years and compared to octogenarians showed a significantly higher logistic EuroScore (27.7±14.8% vs. 23.1±14.4, p=0.005) and STS Score (8.5±4.8% vs. 6.3±6.7, p=0.001). RESULTS: There were no significant differences with regard to stroke rate, pacemaker implantation rate and major vascular complications between the two groups. Thirty-day mortality was 9.8% in nonagenarians and 4.1% in octogenarians (p=0.04). At 1 year, all-cause mortality increased to 30.9% vs. 18.6% (n.s.). CONCLUSION: Nonagenarians showed an increased periprocedural mortality during TAVI and higher mortality in follow-up compared to octogenarians. Age alone is not a predictive factor but indication for treatment should be carefully evaluated by the heart team on an individual basis.

Clopidogrel significantly lowers the development of atherosclerosis in ApoE-deficient mice in vivo.

The anti-platelet drug clopidogrel has been shown to modulate adhesion molecule and cytokine expression, both playing an important role in the pathogenesis of atherosclerosis. The aim of this study was to investigate the impact of clopidogrel on the development and progression of atherosclerosis. ApoE(-/-) mice fed an atherogenic diet (cholesterol: 1 %) for 6 months received a daily dose of clopidogrel (1 mg/kg) by i.p. injection. Anti-platelet treatment was started immediately in one experimental group, and in another group clopidogrel was started 2 month after beginning of the atherogenic diet. Blood was analysed at days 30, 60 and 120 to monitor the lipid profile. After 6 months the aortic arch and brachiocephalic artery were analysed by Sudan IV staining for plaque size and by morphometry for luminal occlusion. Serum levels of various adhesion molecules were investigated by ELISA and the cellular infiltrate was analysed by immunofluorescence. After daily treatment with 1 mg/kg clopidogrel mice showed a significant reduction of atherosclerotic lesions in the thoracic aorta and within cross sections of the aortic arch [plaque formation 55.2 % (clopidogrel/start) vs. 76.5 % (untreated control) n = 8, P < 0.05]. After treatment with clopidogrel P-/E-selectin levels and cytokine levels of MCP-1 and PDGFß were significantly reduced as compared to controls. The cellular infiltrate showed significantly reduced macrophage and T-cell infiltration in clopidogrel-treated animals. These results show that clopidogrel can effectively delay the development and progression of 'de-novo' atherosclerosis. However, once atherosclerotic lesions were already present, anti-platelet treatment alone did not result in reverse remodelling of these lesions.

Clopidogrel reduces post-transplant obliterative bronchiolitis.

Survival after lung transplantation is mainly limited by the development of chronic lung allograft dysfunction (CLAD). The aim of this study was to investigate if platelet inhibition by clopidogrel has an influence on the formation of obliterative bronchiolitis, the histopathological correlate to bronchiolitis obliterans syndrome, present in the majority of patients suffering from CLAD. C57Bl/6(H2(b) ) donor tracheas were orthotopically transplanted into CBA.J(H2(k) ). Mice received different doses of clopidogrel alone or in combination with tacrolimus or everolimus. Grafts were analyzed by histology and immunofluorescence method on postoperative days 15, 30 or 60. Cytokines were analyzed by real-time polymerase chain reaction on postoperative day 21 and alloantibodies by FACS. Mice treated with 20 mg/kg/day clopidogrel for 30 days showed reduced obliteration [34.40 ± 3.76% (20 mg/kg/day clopidogrel) vs. 49.92 ± 2.11% (control), n = 5, P < 0.05]. Platelet inhibition resulted in significant lower infiltration of T cells and macrophages, and we also found significantly lower expression of IL-12, IL-4, IL-6, TNF-α, TGF-ß, PDGFß, MCP1, P-/E-selectin, ICAM1 and CD40L after treatment with clopidogrel. Combination of 1 mg/kg/day clopidogrel and 0.05 mg/kg/day everolimus or 12 mg/kg/day tacrolimus revealed a synergistic effect. Humoral immunity as manifested by donor-specific alloantibody secretion was also impaired after treatment with clopidogrel. Here, we can show that platelet inhibition by clopidogrel as a single treatment and in combination with tacrolimus or everolimus reduced the development of fibrosis and obliteration in tracheal allografts.

Direct Impact of Human Platelets on the Development of Transplant Arteriosclerosis.

BACKGROUND: Platelets play an important role in the pathogenesis of inflammatory and proliferative vascular changes. The aim of this study was to investigate whether human platelets are able to induce transplant arteriosclerosis in a humanized C57/Bl6-Rag2-/-γc-/- mouse xenograft model. METHODS: Nonactivated and in vitro-activated human platelets were analyzed and phenotyped for surface markers by flow cytometry. Side branches of human mammary arteries were implanted into the infrarenal aorta of recipients, followed by daily application of human platelets and histological analyzed on day 30 after transplantation. RESULTS: Human platelets collected by apheresis had low levels of platelet activation markers. However, after in vitro activation, expression was markedly increased. Sixty minutes after injection in recipient mice, nonactivated human platelets become significantly activated. Increased adhesion of platelets to the vascular endothelium was detected by in vivo fluorescence microscopy. After intravenous injection of nonactivated or activated platelets, human xenografts showed pronounced intimal proliferation. Immunohistological analysis showed that the group treated with activated human platelets exhibited significantly increased intragraft protein expression of intracellular adhesion molecule-1 and platelet-derived growth factor receptor beta and smooth muscle cell migration into the neointima. CONCLUSIONS: These data demonstrate that an isolated daily application of both in vivo- and in vitro-activated human platelets results in the development of transplant arteriosclerosis in a humanized mouse transplantation model.

Nintedanib reduces alloimmune-induced chronic airway changes in murine tracheal allografts.

BACKGROUND: The major obstacle for long-term survival after successful lung transplantation is the development of bronchiolitis obliterans (BO) which is one phenotype of chronic lung allograft dysfunction (CLAD). Nintedanib has beneficial effects treating neoplastic diseases and idiopathic pulmonary fibrosis by blocking tyrosine kinase receptors. These receptors play an important role in alloimmune-mediated proliferative diseases. The aim of this study was to determine the effect of nintedanib on proliferative airway changes after orthotopic trachea transplantation in mice. METHODS: C57BL/6 mice (H-2b) donor tracheas were orthotopically transplanted into CBA/J mice (H-2k). After transplantation, recipients were daily treated with nintedanib (60 mg/kg; p.o.). Histological and immunofluorescence analysis were performed after 30 days and intragraft gene expression measurements after 14 days of treatment, respectively. RESULTS: Tracheal allografts from mice treated with nintedanib showed significantly less features of chronic rejection than untreated allografts reflected in a higher epithelium/lamina propria ratio (ELR) [ELR: 0.65 ± 0.13 nintedanib vs. 0.50 ± 0.07 untreated controls; p < 0.05] and a reduced submucosal smooth muscle actin (SMA) content [SMA: 1.26% ± 0.78% nintedanib vs. 2.18% ± 1.01% untreated controls; p < 0.01]. Furthermore, lower T cell, macrophage and dendritic cell infiltration was detected in the nintedanib treated grafts. The protein and intragraft mRNA expression of receptor subtypes was considerably decreased in grafts of nintedanib treated mice. The mRNA expression of relevant immune mediators was affected by nintedanib treatment. CONCLUSION: Receptor blocking by nintedanib reduced alloimmune-induced inflammation and chronic airway changes in mouse trachea allografts and might be a promising approach to diminish the development of BO in lung transplants.

Cytomegalovirus Donor Seropositivity Negatively Affects Survival After Heart Transplantation.

BACKGROUND: Prior studies have shown that cytomegalovirus (CMV) infection is a risk factor for the development of cardiac allograft vasculopathy (CAV) and is associated with reduced long-term survival after heart transplantation (HTx). The aim of this International Society for Heart and Lung Transplantation Transplant Registry study was to compare posttransplant survival in different CMV donor:recipient serologic combinations. METHODS: We performed a retrospective cohort study, using the International Society for Heart and Lung Transplantation Thoracic Transplant Registry, on 15 885 adult primary heart transplant recipients with known CMV serologic status between July 2004 and June 2014. Posttransplant survival and risk of developing CAV were compared across 4 groups: CMV-seronegative recipients (R-) receiving CMV-positive grafts (D+), intermediate-risk patients (D+R+ and D-R+), and low-risk patients (D-R-). RESULTS: Baseline characteristics (donor/recipient age, body mass index, recipient serum creatinine, blood group, donor cause of death, recipient diagnosis, and ischemic time) were mostly balanced between the groups. Kaplan-Meier survival analyses over a follow-up of 10 y revealed significantly worse survival for both D+ groups as compared to the CMV low-risk group (D+R+: 56.61% [95% confidence interval, 53.94-59.41] versus D-R-: 63.09% [59.74-66.64] P < 0.01 and D+R-: 57.69% [56.03-59.39] versus D-R-; P < 0.001), whereas recipient seropositivity alone was not associated with reduced survival (D-R+ versus D-R-P = 0.178). The risk of developing CAV after HTx was not significantly increased in D+ as compared to D- groups. CONCLUSIONS: In a large contemporary cohort, CMV status at the time of HTx was not associated with CAV development. However, there was a significant association between donor CMV seropositivity and reduced short- and long-term survival after HTx. Approaches to mitigate the impact of CMV on posttransplant survival are needed.

Microvasculature in murine tracheal allografts after combined therapy with clopidogrel and everolimus.

OBJECTIVES: Survival after lung transplantation is mainly limited by the development of chronic lung allograft dysfunction. Previous studies have suggested T-cell mediated proliferation and microvascular changes in experimental small airways models as potential therapeutic targets. The aim of this study was to assess microvascular changes in murine orthotopic tracheal allografts after treatment with everolimus alone or in combination with clopidogrel. METHODS: C57Bl/6 (H-2b) donor tracheas were orthotopically transplanted into CBA (H-2k) recipients. Mice received daily injections of everolimus (0.05 mg/kg) alone or combined with clopidogrel (1 mg/kg). Twenty-eight days after transplantation, ratio of the thickness of tracheal epithelium and lamina propria was measured as an indicator for chronic rejection. Additionally, graft oxygenation and graft perfusion were detected on postoperative days 4, 10 and 28. Quantitative reverse transcription polymerase chain reaction analysis was used for gene expression analysis. RESULTS: While syngeneic grafts showed a stable tissue pO2 and undisturbed microvascular perfusion, rejecting allografts had a drastic decline in both parameters as well as a flattened epithelium and an increased thickness of the lamina propria. Treatment with everolimus reduced allogeneic fibroproliferation, but had no protective effects on the microvasculature; polymerase chain reaction analysis indicated hypoxic stress and inflammation. Combining everolimus with clopidogrel improved microvascular integrity in the tracheal grafts, but had no synergistic effect in preventing obliterative bronchiolitis development. CONCLUSIONS: These data demonstrate that the ability of everolimus to reduce the development of post-transplant obliterative bronchiolitis is not caused by microvascular protection and has no synergistic effects with clopidogrel in acute airway rejection.

Combination of clopidogrel and everolimus dramatically reduced the development of transplant arteriosclerosis in murine aortic allografts.

Our group has shown that platelet inhibition with clopidogrel, an antagonist of the P2Y12 adenosine diphosphate receptor on platelets, reduced the formation of transplant arteriosclerosis. The aim of this study was to investigate whether a combination of cyclosporin or everolimus with clopidogrel has a beneficial effect on the development of transplant arteriosclerosis. Fully MHC mismatched C57Bl/6 (H2(b)) donor aortas were transplanted into CBA.J (H2(k)) recipients and mice received either clopidogrel alone (1 mg/kg/day) or in combination with cyclosporin (2 mg/kg/day) or everolimus (0.05 mg/kg/day). Grafts were analysed by histology and morphometry on day 30 after transplantation. In mice treated with clopidogrel alone, transplant arteriosclerosis was significantly reduced [intima proliferation 56 +/- 11% vs. 81 +/- 7% (control)/n = 7]. Daily application of everolimus reduced the development of transplant arteriosclerosis compared with untreated controls [intima proliferation of 29 +/- 9% vs. 81 +/- 7% (control)/n = 7]. Strikingly, combination of clopidogrel and everolimus almost abolished the formation of transplant arteriosclerosis [intima proliferation: 11 +/- 8% vs. 81 +/- 7% (control)/n = 7]. By contrast, combination of cyclosporin and clopidogrel compared with clopidogrel alone showed no additive effect. These results demonstrate that combination of platelet- and mammalian target of Rapamycin-inhibition can dramatically reduce the development of transplant arteriosclerosis.