A Novel Three-Dimensional Approach Towards Evaluating Endomyocardial Biopsies for Follow-Up After Heart Transplantation: X-Ray Phase Contrast Imaging and Its Agreement With Classical Histopathology.

Endomyocardial biopsies are the gold standard for surveillance of graft rejection following heart transplantation, and are assessed by classical histopathology using a limited number of previously stained slices from several biopsies. Synchrotron propagation-based X-ray phase contrast imaging is a non-destructive method to image biological samples without tissue preparation, enabling virtual 2D and 3D histopathology. We aimed to show the feasibility of this method to assess acute cellular rejection and its agreement to classical histopathology. Right ventricular biopsies were sampled from 23 heart transplantation recipients (20 males, mean age 54±14 years) as part of standard follow-up. The clinical diagnosis of potential rejection was made using classical histopathology. One additional study sample was harvested and imaged by X-ray phase contrast imaging, producing 3D datasets with 0.65 µm pixel size, and up to 4,320 images per sample. An experienced pathologist graded both histopathological and X-ray phase contrast images in a blinded fashion. The agreement between methods was assessed by weighted kappa, showing substantial agreement (kappa up to 0.80, p < 0.01) between X-ray phase contrast imaging and classical histopathology. X-ray phase contrast imaging does not require tissue processing, allows thorough analysis of a full myocardial sample and allows identification of acute cellular rejection.

Transcatheter Aortic Valve Implantation Induces Transient Drop in Platelet Reactivity.

ABSTRACT: Although recent studies described platelet reactivity (PR) changes in days after transcatheter aortic valve implantation (TAVI), precise time course and duration of these changes have not been fully investigated. The aim of this study was to investigate PR pattern during and after TAVI in multiple time points. Study included 40 consecutive patients undergoing TAVI. All patients underwent the procedure on dual antiplatelet therapy. PR was measured in 7 time points: before induction of anesthesia (T1), after heparin administration (T2), 10 minutes after initial valve implantation (T3), at the end of procedure (T4), and on 3rd, 6th, and 30th postoperative day (T5-T7). PR was measured using impedance aggregometer using 3 different platelet aggregation agonists (arachidonic acid in ASPItest, adenosine diphosphate in ADPtest and thrombin receptor activating peptide 6 in TRAPtest). All patients underwent successful TAVI procedure. Mean PR on T1 was 22.9 ± 23.0 U for ASPItest, 40.5 ± 23.7 U for ADPtest and 91.7 ± 32.5 U for TRAPtest. There was no significant difference in PR on T2. On T3, significant reduction of PR in all 3 tests was observed [ASPI 10.4 ± 11.6 U (P = 0.001), ADP 24.2 ± 14.1 U (P < 0.001) and TRAP 69.3 ± 26.6 U (P < 0.001)]. PR nadir for all tests was reached on T5, with subsequent PR incline. PR values in all tests returned to baseline levels on T7. Our results show that successful TAVI procedure induces transient decrease in PR regardless of the platelet activation pathway.

Severe bleeding caused by piperacillin/tazobactam-induced platelet dysfunction
.

OBJECTIVE: Piperacillin/tazobactam (TZP ) is commonly used against multi-resistant nosocomial Pseudomonas infections. While TZP-induced thrombocytopenia is a well-known and easily diagnosed complication, we herein present an unusual case of spontaneous TZP-induced bleeding caused by platelet dysfunction. CASE SUMMARY: A 73-year-old-man experienced severe pulmonary hemorrhage and bloody diarrhea during the treatment with TZP for Pseudomonas aeruginosa ventilator-associated pneumonia. While both platelet count and coagulation tests were normal, platelet functional test revealed severely impaired ADP-dependent platelet aggregation. CONCLUSION: Platelet dysfunction is a little-known mechanism of TZP-induced bleeding. This is the second reported case of TZP-related bleeding that has been attributed to platelet dysfunction, and the first case report that has not been associated with surgery. While thrombocytopenia is easily recognized, this form of TZP-induced bleeding can be detected only by platelet functional tests.

Impact of Continuous P2Y12 Inhibition Tailoring in Acute Coronary Syndrome and Genetically Impaired Clopidogrel Absorption.

Clopidogrel is still widely used in acute coronary syndrome despite the development of more potent P2Y12 inhibitors. Previously, we conducted a trial that evaluated serial clopidogrel dose adjustment based on platelet function testing in acute coronary syndrome patients with initial high on-treatment platelet reactivity (HTPR). In this substudy, we performed post hoc analysis of the effect of ABCB1 genetic variants C3435T and G2677T/A on platelet inhibition and outcomes. There were no differences in the proportion of HTPR patients among C3435T carriers and noncarriers in both interventional and control group. G2677T carriers expressed significantly higher proportion of HTPR pattern throughout 12-month follow-up in the control group with no difference in the interventional group. There was no difference in ischemic outcomes between C3435T and G2677T carriers and noncarriers in both groups of patients. The results indicate that ABCB1 genotyping is not useful to guide clopidogrel therapy tailoring to improve high-risk patient management.

A case report of acute inferior myocardial infarction in a patient with severe hemophilia A after recombinant factor VIII infusion.

RATIONALE: The extent of protective effects of hemophilia against thrombotic events such as myocardial infarction (MI) and other acute coronary syndromes remains to be determined, as major risk factors for cardiovascular disease exist despite factor VIII (FVIII) deficiency. We present a case report of a 41-year-old male with severe hemophilia A and several cardiovascular risk factors. PATIENT CONCERNS: This morbidly obese patient developed chest pressure, followed by chest pain and difficulty in breathing shortly after receiving on-demand treatment with intravenous recombinant FVIII (rFVIII) (turoctocog alfa) dosed per body weight. DIAGNOSES: An electrocardiogram revealed a diagnosis of inferior ST-segment elevation MI. INTERVENTIONS: The patient underwent an urgent coronary angiography using a radial artery approach. During the next 12 months, he received dual antiplatelet treatment, acetylsalicylic acid 100 mg, and clopidogrel 75 mg daily. His treatment for severe hemophilia A was changed to plasma-derived FVIII replacement therapy. OUTCOMES: During this 12-month period, he experienced several small bleeds in his elbows. CONCLUSIONS: The temporal relationship between rFVIII infusion and onset of the MI suggests a possible association; however, apart from obesity, the patient also had other major risk factors for arterial thrombosis, such as hypertension and smoking. Furthermore, atherosclerotic disease and underlying atherosclerotic changes could not be excluded with certainty. This case highlights the importance of studies assessing the impact of excess body weight on rFVIII dosing.

Urgent Heart Retransplant in an Adult Patient With Anthracycline-Induced Cardiomyopathy After Diffuse Large B-Cell Lymphoma - Case Report.

Heart retransplant is a treatment option for some patients with graft failure. With heart donor short-age, it is important to assess candidates carefully for cardiac retransplant. An adult patient had a successful urgent heart retransplant due to severe toxic cardiomyopathy (anthracycline-induced) after posttransplant lymphoproliferative disease that was a diffuse large B-cell lymphoma.

The predictive value of platelet function point-of-care tests for postoperative blood loss and transfusion in routine cardiac surgery: a systematic review.

Excessive bleeding after cardiopulmonary bypass (CPB) operations remains to be a persistent problem and weak platelet function certainly contributes to bleeding diathesis. Antiplatelet therapy (APT) is an integral component of perioperative management in patients undergoing cardiac surgery procedures, both with and without use of CPB. In addition to individual variability in platelet function, different preoperative APT administration/discontinuation management further affects platelet function, which in turn may reflect bleeding tendency. However, the impact of drug-induced platelet inhibition on early postoperative bleeding extent remains difficult to predict. Herein, we reviewed the available evidence on the association between platelet function testing values and the extent of bleeding and transfusion requirements in early perioperative period. Currently, the association between platelet function measured by ex vivo assay and the occurrence of bleeding events remains uncertain. The intent of this review is to provide comprehensive literature insight into published evidence, investigating the possibility of platelet function tests to predict bleeding extent as well as transfusion requirements in cardiac surgery patients.

Pretransplant and perioperative predictors of early heart transplantation outcomes.

Aim. To identify predictors of 3-month mortality after heart transplantation in a Croatian academic center. Methods. A retrospective review of institutional database identified 117 heart transplantations from January 2008 to July 2014. Two children <14 years were excluded from the study. The remaining 115 patients were dichotomized into survivors and non-survivors adjudicated at 3-months postoperatively, and their demographic, clinical, and longitudinal hemodynamic data were analyzed. Results. 3-month survival after heart transplantation was 86%. Non-survivors were older (59±8 vs 50±14 years, P=0.009), more likely to have previous cardiac surgery (44% vs 19%; odds ratio [OR] 3.28, 95% confidence interval [CI] 1.08-9.90; P=0.029), lower body mass index (BMI) (25±4 vs 28±2 kg/m(2), P=0.001), and be diabetics (44% vs 23%; OR 2.57, 95% CI 0.86-7.66; P=0.083). Creatinine clearance was marginally superior among survivors (59=19 vs 48 ± 20 mL/min, P=0.059). Donor age and sex did not affect outcomes. Non-survivors were more likely to have had ischemic cardiomyopathy (69% vs 32%, P=0.010). Postoperative utilization of epinephrine as a second line inotropic agent was a strong predictor of mortality (63% vs 7%; OR 21.91; 95% CI 6.15-78.06; P<0.001). Serum lactate concentrations were consistently higher among non-survivors, with the difference being most pronounced 2 hours after cardiopulmonary bypass (9.8±3.5 vs 5.2±3.2 mmol/L, P<0.001). The donor hearts exhibited inferior early hemodynamics in non-survivors (cardiac index 3.0±1.0 vs 4.0±1.1 L/min/m(2), P=0.001), stroke volume (49±24 vs 59±19 mL, P=0.063), and left and right ventricular stroke work indices (18±8 vs 30±11 g/beat/m(2), P<0.001 and 5±3 vs 7±4 g/beat/m(2), P=0.060, respectively). Non-survivors were more likely to require postoperative re-sternotomy (50% vs 12%; OR 7.25, 95% CI 2.29-22.92; P<0.001), renal replacement therapy (RRT) (69% vs 9%; OR 22.00, 95% CI 6.24-77.54; P<0.001), and mechanical circulatory assistance (MCS) (44% vs 5%; OR 14.62, 95% CI 3.84-55.62; P<0.001). Binary logistic regression revealed recipient age (P=0.024), serum lactates 2 hours after CPB (P=0.007), and epinephrine use on postoperative day 1 (P=0.007) to be independently associated with 3-month mortality. Conclusion. Pretransplant predictors of adverse outcome after heart transplantation were recipient age, lower BMI, ischemic cardiomyopathy, reoperation and diabetes. Postoperative predictors of mortality were inferior donor heart hemodynamics, epinephrine use, and serum lactate concentrations. Non-survivors were more likely to require re-sternotomy, MCS, and RRT.