Antithrombotic therapy after heart valve surgery: contemporary practice in the UK.

OBJECTIVES: There is a lack of high-quality data informing the optimal antithrombotic drug strategy following bioprosthetic heart valve replacement or valve repair. Disparity in recommendations from international guidelines reflects this. This study aimed to document current patterns of antithrombotic prescribing after heart valve surgery in the UK. METHODS: All UK consultant cardiac surgeons were e-mailed a custom-designed survey. The use of oral anticoagulant (OAC) and/or antiplatelet drugs following bioprosthetic aortic valve replacement or mitral valve replacement, or mitral valve repair (MVrep), for patients in sinus rhythm, without additional indications for antithrombotic medication, was assessed. Additionally, we evaluated anticoagulant choice following MVrep in patients with atrial fibrillation. RESULTS: We identified 260 UK consultant cardiac surgeons from 36 units, of whom 103 (40%) responded, with 33 units (92%) having at least 1 respondent. The greatest consensus was for patients undergoing bioprosthetic aortic valve replacement, in which 76% of surgeons favour initial antiplatelet therapy and 53% prescribe lifelong treatment. Only 8% recommend initial OAC. After bioprosthetic mitral valve replacement, 48% of surgeons use an initial OAC strategy (versus 42% antiplatelet), with 66% subsequently prescribing lifelong antiplatelet therapy. After MVrep, recommendations were lifelong antiplatelet agent alone (34%) or following 3 months OAC (20%), no antithrombotic agent (20%), or 3 months OAC (16%). After MVrep for patients with established atrial fibrillation, surgeons recommend warfarin (38%), a direct oral anticoagulant (37%) or have no preference between the 2 (25%). CONCLUSIONS: There is considerable variation in the use of antithrombotic drugs after heart valve surgery in the UK and a lack of high-quality evidence to guide practice, underscoring the need for randomized studies.

Offset of ticagrelor prior to coronary artery bypass graft surgery for acute coronary syndromes: effects on platelet function and cellular adenosine uptake.

Ticagrelor is an antagonist of both platelet adenosine diphosphate (ADP) receptor P2Y12 and equilibrative nucleoside transporter-1. Optimal timing of ticagrelor cessation prior to coronary artery bypass grafting (CABG) remains unclear. We characterized the offset of ticagrelor's effects on platelets and cellular adenosine uptake in ticagrelor-treated patients (n = 13) awaiting CABG. Blood was drawn prior to CABG at multiple timepoints 2 to 120 (h) after the last dose of ticagrelor. Platelet function (n = 13) was assessed with multiple electrode aggregometry (MEA), expressed as arbitrary units (U) derived from area-under-the-curve (AUC) in response to ADP, and inhibition of adenosine uptake by high-performance liquid chromatography (n = 7). Mean±SD AUC was 20.3 ± 8.2 U (2 h post-ticagrelor), 33.0 ± 18.3U (24 h), 56.6 ± 30.6U (48 h), 61.4 ± 20.2U (72 h), 82.8 ± 24.2U (96 h) and 96.0 ± 15.3U (120 h). There was a significant difference between 72 h and 120 h (p = .007), but not between 96 h and 120 h (p > .99). By 96 h, all patients had AUC >31U, an accepted cutoff below which surgical bleeding risk is increased. Adenosine uptake showed no significant differences between the timepoints. These data suggest it takes 4 days for platelet reactivity to recover sufficiently after cessation of ticagrelor to avoid the excess risk of CABG-related bleeding. Discontinuing ticagrelor had no measurable effect on cellular adenosine uptake.

A rare case of giant coronary artery aneurysm in the context of multiple arterial aneurysms.

INTRODUCTION: Whilst the incidence of CAA has been reported as up to 5%, giant CAA (>2cm) is rare. PRESENTATION OF CASE: We present a rare case of 3cm×4cm giant coronary artery aneurysm (CAA) in the context of aorto-iliac aneurysmal disease, treated by staged open surgical repair. DISCUSSION: Abdominal aortic aneurysm (AAA) and CAA share risk factors and aetiological mechanisms, therefore should be considered, particularly when CAA is diagnosed in the first instance. CONCLUSIONS: Surgical intervention for diagnosed giant CAA appears to be the treatment of choice in the reported literature, with the order of intervention when AAA co-exists remaining a point for debate.

Atrial myxomas: a single unit's experience in the modern era.

BACKGROUND: Although an atrial myxoma is the commonest cardiac tumor, it is still relatively rare, with an annual incidence of approximately 0.5 per million. In our unit, which performs 1000 major cardiac procedures per year, this equates to approximately 3 patients annually. We therefore sought to evaluate our experience of managing this type of tumor over the last 5 years. METHODS: A retrospective review was performed of prospectively collected data from the departmental database. We analyzed consecutive patients who were operated upon between 2002 and 2007. Three patients with a papillary fibroelastoma on histological examination were excluded from this study. RESULTS: We have performed excision of atrial myxoma in 18 patients. Twelve patients (66%) were female; the median age was 64 years (range, 35-80 years), and the median logistic euroSCORE was 5.22% (range, 1.51-27.82%). Fifteen patients (83%) were deemed urgent, 2 elective, and 1 emergency. Sixteen tumors (89%) were left sided. Symptoms attributable to the tumor were found in 16 of the 18 patients (embolic, n = 9; chest pain, n = 3; palpitations, n = 2; incidental finding, n = 2, others n = 4), and the mean time from diagnosis to operation was 3 days (range, 0-22 months). The median cardiopulmonary bypass time was 87 minutes (range, 28-228 minutes), with the median aortic cross clamp time being 61 minutes (16-175 minutes).The approaches used were transeptal via right atriotomy (n = 8), biatrial/Dubost (n = 4), left atrial (n = 4), and right atrial (n = 2); the interatrial septum was involved in 14 patients. The resultant defect was closed using a pericardial (n = 8) or prosthetic patch (n = 5) or directly sutured (n = 5). Concomitant procedures were performed in 8 patients (coronary artery bypass graft [CABG], n = 4; mitral valve replacement [MVR], n = 2; valve + grafts, n = 2). All tumors were completely excised.Postoperatively there were no deaths within 30 days of the procedure. Indeed, only 2 patients have died at 4 and 25 months postoperatively, respectively, both of unrelated causes. Median intensive therapy unit (ITU) stay was 2 days (range, 1-9 days), and median hospital stay was 10 days (range, 5-20 days). A permanent pacemaker was required in only 1 patient, and median blood loss was 340 mL (range, 140-1760 mL). Atrial fibrillation was the commonest complication affecting 6/18 patients (33%). CONCLUSIONS: Excision of atrial myxoma can be performed using a variety of intraoperative approaches and closure techniques, all with acceptable postoperative morbidity and low mortality rates. To date, no recurrences have been found at median 2-year follow-up.

Routine preoperative insertion of IABP in high-risk off-pump coronary artery bypass grafting.

The beneficial effects of intraaortic balloon pump (IABP) in coronary artery bypass graft surgery with cardiopulmonary bypass have been reported. However, whether preoperative insertion of IABP in high-risk off-pump coronary artery bypass grafting (OPCAB) has any beneficial effects remains to be established. We report our experience of preoperative insertion of IABP in OPCAB.

The predictors and outcome of recidivism in cardiac ICUs.

OBJECTIVE: Reinstitution of step-up care (recidivism) following cardiac surgery may be associated with increased mortality. This has, however, not been widely reported. METHODS: We, therefore, studied 8113 consecutive patients who underwent coronary artery bypass grafting (CABG), valve replacement/repair or combined valve+CABG surgery between January 1996 and December 2003 to determine the reasons for readmission to the intensive care unit (ICU) and their outcomes in terms of length of stay in (i) the ICU (ii) hospital and (iii) the in-hospital mortality following recidivism. RESULTS: Of the 7717 patients discharged out of the ICU, 2.3% (182) of patients [mean age 70.4+/-8.35 years (range 30-90 years); 65.4% (119) males] required step-up care. Recidivism was 1.8% (101 of 5633) following coronary artery by-pass grafting (CABG) and 3.9% (81 of 2084) following valve replacement/repair+/-CABG (P<0.05). The mean interval from ICU discharge to ICU recidivism was 6.6+/-8.4 days (range 6h to 28 days). The principal reasons for recidivism were (i) respiratory failure requiring reintubation and ventilation in 54.9% (n=100) of patients (ii) cardiovascular instability (including that secondary to dysrhythmias) and heart failure in 23.1% (n=42) (iii) renal failure requiring haemofiltration in 6.6% (n=12) (iv) sepsis in 1.1% (n=2) (v) cardiac tamponade/bleeding requiring re-exploration in 7.7% (n=14) and (vi) gastro-intestinal complications requiring laparotomy in 6.0% (n=11) patients. Multivariate analysis showed that, during primary ICU stay, respiratory complications, low cardiac output state, dysrhythmias, renal failure requiring haemofiltration and re-exploration for bleeding were independent predictors of recidivism. Following recidivism (i) the mean length of stay in the ICU was 6.65+/-6.2 days (range 4h to 51 days), (ii) mean hospital stay was 19.2+/-17.3 days (10-60 days) and (iii) the 30-day in-hospital mortality was 32.4%. CONCLUSIONS: Patients are more likely to require recidivism following valve surgery+/-CABG than CABG alone. Whilst respiratory complications were the most common reasons for recidivism in our study, patients who required mechanical supports to maintain vital functions following surgery were most prone to recidivism. Hence, efforts should be made to treat cardio-respiratory problems early in this group of patients to reduce ICU recidivism.

Histological and immunological characteristics of, and the effect of immunosuppressive treatment on, xenograft vasculopathy.

Like allografts, vascularized xenografts are susceptible to a process of chronic rejection. We have used the hamster-to-rat aortic transplant model to study characteristics of this phenomenon and to determine whether it could be controlled or prevented by immunosuppressive therapy. Golden Syrian hamster aortas were transplanted into untreated Lewis rats, athymic rats, and Lewis rats receiving cyclosporin (10 mg/kg), leflunomide (5, 10 or 15 mg/kg), or 10 mg/kg of both drugs. Grafts were harvested on days 2, 7, 14, 28 and 56. Grafts and recipient spleens were analysed using computerized morphometry, immunohistochemistry and immunofluorescence. Blood was taken on various days for the measurement of anti-hamster antibodies (flow cytometry) and of the leflunomide metabolite A77 127. In untreated rats, by day 56, transplanted aortas developed a cell-free media with a mature neointimal lesion consisting of actin-positive cells, CD4 T cells, and macrophages. There were large increases in anti-hamster immunoglobulin M (IgM) and IgG, collections of proliferating cell nuclear antigen (PCNA)-positive cells in splenic germinal centres, and IgM, C3 and C5a deposition in aortas. In athymic recipients, the media architecture was preserved, and the changes in the neointima and in anti-hamster IgM and IgG were markedly abrogated, but not prevented. In Lewis rats receiving leflunomide, absence of circulating or deposited IgM did not prevent neointimal formation by day 14. Combination treatment was the most effective at preventing neointimal formation and humoral changes. Leflunomide monotherapy was the least effective. There were no changes in peak concentrations of the main metabolite of leflunomide over 8 weeks. The hamster-to-rat aortic transplant model is suitable for the study of xenograft vasculopathy, the histological and serological changes of which are predominantly T-cell dependent. Combination treatment with 10 mg/kg of cyclosporin and 10 mg/kg of leflunomide was most effective in preventing xenograft vasculopathy.