Periprocedural bridging therapy with low-molecular-weight heparin in chronically anticoagulated patients with prosthetic mechanical heart valves: experience in 116 patients from the prospective BRAVE registry.

BACKGROUND AND AIM OF THE STUDY: The study aim was to determine the safety and feasibility of a standardized bridging regimen in patients with mechanical heart valves at high thromboembolic risk, using low-molecular-weight heparin (LMWH). METHODS: Since the year 2000, all patients at the authors' institution, with mechanical heart valves and a need for periprocedural interruption of oral anticoagulation (OAC), were prospectively enrolled in this registry. Patients were treated with enoxaparin following a pre-specified, standardized bridging regimen. The main outcome measures were the incidence of hemorrhagic or thromboembolic events. The follow up period was 30 days after hospital discharge. RESULTS: A total of 116 patients was included (31 with mitral valve replacement, 76 aortic valve replacement, nine double valve replacement). Patients underwent either major surgery (n = 25), minor surgery (n = 36), pacemaker implantation (n = 21), or coronary catheterization (n = 34). Bridging therapy with enoxaparin was administered for a mean of 7.0 +/- 4.6 days. Eighteen patients (15.5%) were treated as outpatients. In 35 patients (34%) with renal impairment (creatinine clearance <50 ml/min), LMWH dosage was halved. No thromboembolic (95% CI 0-3.1%) and only one major bleeding complication occurred (0.86%; 95% CI 0.02-4.7%); minor bleeding occurred in 10 patients (8.6%; 95% CI 4.2-15.3%). The hemorrhages arose after a mean of 5.4 +/- 1.4 days LMWH therapy. CONCLUSION: Bridging therapy following a standardized LMWH-based regimen with enoxaparin was effective and relatively safe in a large cohort of patients with mechanical heart valves. Extended duration of LMWH therapy seems to promote the incidence of hemorrhage. Neither dose reduction in patients with renal impairment nor outpatient treatment affected the safety and efficacy of this bridging regimen. These findings warrant that more extensive studies be conducted to investigate the safety of this approach.

Post mortem analysis of a left atrial appendage occlusion device (PLAATO) in a patient with permanent atrial fibrillation.

Thromboemoblism is the most feared complication of atrial fibrillation. Percutaneous left atrial appendage occlusion is a new interventional procedure for reducing thromboembolic risk in patients with atrial fibrillation. The paper reports of a post mortem analysis of the device demonstrating that one year after implantation the atrial surface of the device is completely covered by neo-endothelium and the device occludes the appendage completely.

A prospective and randomized comparison of the safety and effects of therapeutic levels of enoxaparin versus unfractionated heparin in chronically anticoagulated patients undergoing elective cardiac catheterization.

Consecutive patients with atrial fibrillation and/or prosthetic heart valves, receiving chronic anticoagulation with phenprocoumon and scheduled to undergo cardiac catheterization, were randomized to subcutaneous enoxaparin twice daily (n = 32) or intravenous UFH (n = 36). Cardiac catheterization was performed at an international normalized ratio <1.5. Activated partial thromboplastin times and levels of anti-Factor Xa activity were measured daily. The time until effective anticoagulation (primary endpoint) was significantly shorter for enoxaparin than for UFH (1.1 +/- 0.4 days versus 3.7 +/- 2.5 days, p<0.0001). The percentage of days of effective anticoagulation was significantly higher in the enoxaparin group than in the UFH group (93.3 +/- 9.5% versus 53.7 +/- 26.6%, p <0.0001). In conclusion, enoxaparin achieves therapeutic levels of anticoagulation more rapidly and consistently than UFH in chronically anticoagulated patients with prosthetic heart valves and/or atrial fibrillation undergoing cardiac catheterization.

Silent and apparent cerebral embolism after retrograde catheterisation of the aortic valve in valvular stenosis: a prospective, randomised study.

BACKGROUND: In most patients, severity of valvular aortic stenosis can be accurately assessed non-invasively by echocardiography. However, retrograde catheterisation of the aortic valve is often undertaken. This procedure has a potential risk of neurological complications, with an unknown incidence of clinically silent embolism. We aimed to establish the frequency of clinically apparent and silent cerebral embolism after this procedure. METHODS: We prospectively randomised 152 consecutive patients with valvular aortic stenosis at a German university hospital to receive either cardiac catheterisation with (n=101) or without (n=51) passage through the aortic valve. Patients underwent cranial MRI and neurological assessment within 48 h before and after the procedure to assess cerebral embolism. Controls were 32 patients without valvular aortic stenosis who underwent coronary angiography and laevocardiography. FINDINGS: 22 of 101 patients (22%) who underwent retrograde catheterisation of the aortic valve had focal diffusion-imaging abnormalities in a pattern consistent with acute cerebral embolic events after the procedure; three of these patients (3%) had clinically apparent neurological deficits. By contrast, none of the patients without passage of the valve, or any of the controls, had evidence of cerebral embolism as assessed by MRI. INTERPRETATION: Patients with valvular aortic stenosis who undergo retrograde catheterisation of the aortic valve have a substantial risk of clinically apparent cerebral embolism, and frequently have silent ischaemic brain lesions. Patients should be informed about these risks, and this procedure should be used only in patients with unclear echocardiographical findings when additional information is necessary for clinical management.

Use of transesophageal contrast echocardiography for excluding left atrial appendage thrombi in patients with atrial fibrillation before cardioversion.

Transesophageal echocardiographic (TEE) guidance of cardioversion in patients with atrial fibrillation is an alternative method to conventional anticoagulation. Although TEE is considered the gold standard for excluding left atrial (LA) thrombi, in some patients dense spontaneous echo contrast (SEC) and artifacts may hamper the identification or exclusion of LA thrombi. Often those patients are refused cardioversion. The purpose of this study was to determine whether the application of echo contrast (Optison, Mallinckrodt, San Diego, Calif) facilitates the exclusion of LA appendage thrombi in this patient group and allows for safer cardioversion. Forty-one patients with atrial fibrillation and dense SEC or inconclusive TEE findings were given echo contrast. Fourteen patients with sinus rhythm served as control participants. Echo contrast completely reduced artifacts in 13 of 22 patients. In 12 of 19 patients with SEC, the LA appendage was completely filled after the application of echo contrast and, thus, SEC was completely suppressed. In 13 of 41 patients, it was filled incompletely and in 9 of 41 patients, a new mass resembling a thrombus was detected. In total, of 25 of 41 patients with inconclusive TEE findings an atrial thrombus was definitively excluded. Those patients underwent cardioversion. None of those patients had a cerebral embolic complication as assessed by cranial magnetic resonance imaging. Thus, the application of echo contrast may facilitate the TEE exclusion of LA appendage thrombi and, hence, improve the safety of TEE-guided cardioversion.