Heyder Omran

Percutaneous Left Atrial Appendage Transcatheter Occlusion to Prevent Stroke in High-Risk Patients With Atrial Fibrillation Early Clinical Experience

Background—Thromboembolism due to atrial fibrillation (AF) is a frequent cause of stroke. More than 90% of thrombi in AF form in the left atrial appendage (LAA). Obliteration of the appendage may prevent embolic complications. Methods and Results—We evaluated the feasibility and safety of implanting a novel device for percutaneous left atrial appendage transcatheter occlusion (PLAATO). LAA occlusion using the PLAATO system was attempted in 15 patients with chronic AF at high risk for stroke, who are poor candidates for long-term warfarin therapy. The implant consists of a self-expanding nitinol cage covered with a polymeric membrane (ePTFE). The LAA was successfully occluded in 15/15 patients (100%). Angiography and transesophageal echocardiography (TEE) during the procedure showed that the device was well-seated in all patients and that there was no evidence of perforation, device embolization, or interference with surrounding structures. In 1 patient, the first procedure was complicated by a hemopericardium, which occurred during LAA access. A second attempt 30 days later was successful with no untoward sequela. No other complications occurred. At 1-month follow-up, chest fluoroscopy and TEE revealed continued stable implant position with smooth atrial-facing surface and no evidence of thrombus. Conclusions—Thus, transcatheter closure of the LAA is feasible in humans. This novel implant technology may be appropriate for patients with AF who are not suitable candidates for anticoagulation therapy. Further trials are needed to show the long-term safety and its efficacy in reducing stroke.

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.

Left atrial appendage occlusion for stroke prevention in atrial fibrillation: multicentre experience with the AMPLATZER Cardiac Plug.

AIMS To investigate the safety, feasibility, and efficacy of left atrial appendage occlusion (LAAO) with the AMPLATZER Cardiac Plug (ACP) for stroke prevention in patients with atrial fibrillation (AF). METHODS AND RESULTS Data from consecutive patients treated in 22 centres were collected. A total of 1,047 patients were included in the study. Procedural success was 97.3%. There were 52 (4.97%) periprocedural major adverse events. Follow-up was complete in 1,001/1,019 (98.2%) of successfully implanted patients (average 13 months, total 1,349 patient-years). One-year all-cause mortality was 4.2%. No death at follow-up was reported as device-related. There were nine strokes (0.9%) and nine transient ischaemic attacks (0.9%) during follow-up. The annual rate of systemic thromboembolism was 2.3% (31/1,349 patient-years), which is a 59% risk reduction. There were 15 major bleedings (1.5%) during follow-up. The annual rate of major bleeding was 2.1% (28/1,349 patient-years), which is a 61% risk reduction. Patients with single LAAO on aspirin monotherapy or no therapy and longer follow-up had fewer cerebral and fewer bleeding events. CONCLUSIONS In this multicentre study, LAAO with the ACP showed high procedural success and a favourable outcome for the prevention of AF-related thromboembolism. Modification in antithrombotic therapy after LAAO may result in reduction of bleeding events.

PLAATO (Percutaneous Left Atrial Appendage Transcatheter Occlusion) for prevention of cardioembolic stroke in non-anticoagulation eligible atrial fibrillation patients: results from the European PLAATO study

The European PLAATO (Percutaneous Left Atrial Appendage Transcatheter Occlusion) study was performed to determine the safety and efficacy of left atrial appendage occlusion by catheter technique. Embolic stroke due to atrial fibrillation is a common observation, especially in the elderly. Most thrombi in atrial fibrillation form in the left atrial appendage (LAA), its occlusion may therefore reduce the incidence of stroke in these patients.

The HAS-BLED score predicts bleedings during bridging of chronic oral anticoagulation. Results from the national multicentre BNK Online bRiDging REgistRy (BORDER).

Patients who receive long-term oral anticoagulant (OAC) therapy often require interruption of OAC for an elective invasive procedure. Current guidelines allow bridging therapy with either unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH). Apart from the risk of embolism, bleeding is an important complication in this setting and the optimal perioperative management of such patients is still under discussion. The aims of this prospective, observational, multicentre registry of patients treated by cardiologists were: 1) to evaluate current practice of perioperative management of OAC in a large outpatient cohort, 2) to document embolic and haemorrhagic events, and 3) to identify risk factors predicting adverse events. In the years 2009 and 2010, 1,000 invasive procedures (cardiac catheterisation n=533, pacemaker implantation n = 128, surgery n = 194, other n = 145) were performed in patients with OAC. Sixty- one (6.1%) of those patients did not receive bridging therapy during interruption of OAC, 937 (93.7%) patients were treated with LMWH, two patients (0.2%) received UFH. In 22 patients (2.2%) LMWHs were given in prophylactic dose, 727 patients (72.7%) were treated with halved therapeutic (i.e. weight-adapted) LMWH doses and 188 (18.8%) received full therapeutic LMWH doses. Four thromboembolic complications were observed during 30 days of follow-up (two retinal embolisms, one stroke, one myocardial infarction; 0.4%). One major bleeding (0.1%) and 35 clinically relevant bleedings (3.5%) occurred. Rehospitalisation after bleedings was necessary in 20 patients. Independent predictors for bleedings were history of mechanical heart valve replacement (MVR) (p=0.0002) and the HAS-BLED score (<0.0001), with a cut off value ≥ 3 being the most predictive variable for haemorrhage (hazard ratio 11.8, 95% confidence interval 5.6-24.9, p<0.0001). A total of 527 patients with atrial fibrillation and a CHADS₂ score ≤ 2 received halved therapeutic or full therapeutic dosages of LMWH despite a low embolic risk, whereas 49 of the patients with heart valve replacement (51%) did not receive dosages of bridging therapy as recommended in guidelines. In conclusion, in this registry of patients treated by cardiologists, 94% of patients who required interruption of OAC before invasive procedures received LMWH as a bridging therapy, of whom 73% were treated with halved therapeutic LMWH-dosages. Guideline recommendations were followed in only 31% of cases. Importantly, 69% of patients with AF were over-treated while 51% of patients with heart valve replacement were under-treated with LMWHs. A HASB-BLED score ≥ 3 was highly predictive of bleeding events.

Transverse Conduction Capabilities of the Crista Terminalis in Patients With Atrial Flutter and Atrial Fibrillation

OBJECTIVES In this study, the transverse conduction capabilities of the crista terminalis (CT) were determined during pacing in sinus rhythm in patients with atrial flutter and atrial fibrillation. BACKGROUND It has been demonstrated that the CT is a barrier to transverse conduction during typical atrial flutter. Mapping studies in animal models provide evidence that this is functional. The influence of transverse conduction capabilities of the CT on the development of atrial flutter remains unclear. METHODS The CT was identified by intracardiac echocardiography. The atrial activation at the CT was determined during programmed stimulation with one extrastimulus at five pacing sites anteriorly to the CT in 10 patients with atrial flutter and 10 patients with atrial fibrillation before and after intravenous administration of 2 mg/kg disopyramide. Subsequently, atrial arrhythmias were reinduced. RESULTS At baseline, pacing with longer coupling intervals resulted in a transverse pulse propagation across the CT. During shorter coupling intervals, split electrograms and a marked alteration of the activation sequence of its second component were found, indicating a functional conduction block. In patients with atrial flutter, the longest coupling interval that resulted in a complete transverse conduction block at the CT was significantly longer than that in patients with atrial fibrillation (285 +/- 49 ms vs. 221 +/- 28 ms; p < 0.05). After disopyramide administration, a transverse conduction block occurred at longer coupling intervals as compared with baseline (287 +/- 68 ms vs. 250 +/- 52 ms; p < 0.05). Subsequently, a sustained atrial arrhythmia was inducible in 15 of 20 patients. This was atrial flutter in three patients with previously documented atrial fibrillation and in eight patients with history of atrial flutter. Mapping revealed a conduction block at the CT in all of these patients. CONCLUSIONS It was found that the CT provides transverse conduction capabilities and that the conduction block during atrial flutter is functional. Limited transverse conduction capabilities of the CT seem to contribute to the development of atrial flutter.

Color-coded Doppler imaging of the vena contracta as a basis for quantification of pure mitral regurgitation

The narrowest central flow region of a jet is defined as the vena contracta. This term is applied also to the contracted zone of the Doppler color flow image of a jet at its passage through an incompetent mitral valve. The clinical applicability of measuring the size of the vena contracta by transthoracic color-coded Doppler echocardiography for estimating the severity of mitral regurgitation (MR) was evaluated. In 78 of 82 patients with angiographically proved MR, a coherent flow image across the valve was visualized. The maximal diameter in the apical long-axis view was considered as a representative value for the size of the vena contracta. In comparison with the maximal left atrial velocity pixel area, this parameter revealed higher correlations to the angiographic degree of MR and to the regurgitant volume (r = 0.94 vs 0.72, and 0.83 vs 0.71, respectively). The highest positive and negative predictive accuracies for differentiating mild-to-moderate from severe MR were determined for a diameter of 6.5 mm (88 and 96%, respectively). Because the vena contracta is directly related to the severity of MR, it is concluded that it is helpful to use this parameter instead of the maximal velocity pixel area for semiquantitative grading.

D-Ribose improves diastolic function and quality of life in congestive heart failure patients: a prospective feasibility study

Patients with chronic coronary heart disease often suffer from congestive heart failure (CHF) despite multiple drug therapies. D‐Ribose has been shown in animal models to improve cardiac energy metabolism and function following ischaemia. This was a prospective, double blind, randomized, crossover design study, to assess the effect of oral D‐ribose supplementation on cardiac hemodynamics and quality of life in 15 patients with chronic coronary artery disease and CHF. The study consisted of two treatment periods of 3 weeks, during which either oral D‐ribose or placebo was administered followed by a 1‐week wash out period, and then administration of the other supplement. Assessment of myocardial functional parameters by echocardiography, quality of life using the SF‐36 questionnaire and functional capacity using cycle ergometer testing was performed. The administration of D‐ribose resulted in an enhancement of atrial contribution to left ventricular filling (40±11 vs. 45±9%, P=0.02), a smaller left atrial dimension (54±20 vs. 47±18 ml, P=0.02) and a shortened E wave deceleration (235±64 vs. 196±42, P=0.002) by echocardiography. Further, D‐ribose also demonstrated a significant improvement of the patients quality of life (417±118 vs. 467±128, P≤0.01). In comparison, placebo did not result in any significant echocardiographic changes or in quality of life. This feasibility study in patients with coronary artery disease in CHF revealed the beneficial effects of D‐ribose by improving diastolic functional parameters and enhancing quality of life.

Imaging of thrombi and assessment of left atrial appendage function: a prospective study comparing transthoracic and transoesophageal echocardiography

Objective To compare the value of current transthoracic echocardiographic systems and transoesophageal echocardiography for assessing left atrial appendage function and imaging thrombi. Design Single blind prospective study. Patients were first investigated by transthoracic echocardiography and thereafter by a second investigator using transoesophageal echocardiography. The feasibility of imaging the left atrial appendage, recording its velocities, and identifying thrombi within the appendage were determined by both methods. Patients 117 consecutive patients with a stroke or transient neurological deficit. Setting Tertiary cardiac and neurological care centre. Results Imaging of the complete appendage was feasible in 75% of the patients by transthoracic echocardiography and in 95% by transoesophageal echocardiography. Both methods were concordant for the detection of thrombi in 10 cases. Transoesophageal echocardiography revealed two additional thrombi. In one of these patients, transthoracic echocardiography was not feasible and in the other the thrombus had been missed by transthoracic examination. In patients with adequate transthoracic echogenicity, the specificity and sensitivity of detecting left atrial appendage thrombi were 100% and 91%, respectively. Recording of left atrial appendage velocities by transthoracic echocardiography was feasible in 69% of cases. None of the patients with a velocity > 0.3 m/s had left atrial appendage thrombi. In the one patient in whom transthoracic echocardiographic evaluation missed a left atrial appendage thrombus, the peak emptying velocity of the left atrial appendage was 0.25 m/s. Conclusions A new generation echocardiographic system allows for the transthoracic detection of left atrial appendage thrombi and accurate determination of left atrial appendage function in most patients with a neurological deficit.

Echocardiographic Parameters for Predicting Maintenance of Sinus Rhythm After Internal Atrial Defibrillation

Chronic atrial fibrillation (AF), which is refractory to external electrical direct current shock and/or pharmacologic cardioversion, may be successfully cardioverted using internal atrial defibrillation. To avoid unnecessary procedures, it is important to be able to predict which patients will revert to AF. Thirty-eight patients with chronic AF underwent successful internal atrial defibrillation and were followed for 6 months after restoration of sinus rhythm. Left atrial (LA) diameter, left ventricular ejection fraction, maximum LA appendage area, and peak emptying velocities of the LA appendage were analyzed to determine which of these factors were associated with recurrence of AF. Forty-nine percent of patients had a recurrence of AF within 6 months following internal atrial defibrillation. The preprocedural ejection fraction (mean +/- SD 59 + 14% vs 57 + 13%, p = 0.63), LA diameter (4.2 +/- 0.6 cm vs 4.5 +/- 0.6 cm, p = 0.16), and LA appendage area (5.0 +/- 1.5 cm2 vs 5.8 +/- 1.5 cm2, p = 0.13) did not differ significantly between patients who maintained sinus rhythm and those who had recurrence of AF. Peak emptying velocities of the LA appendage before cardioversion were significantly lower in patients with recurrence of AF compared with patients who maintained sinus rhythm (0.26 +/- 0.1 m/s vs 0.49 +/- 0.17 m/s, p = 0.001). A peak emptying velocity <0.36 had a sensitivity of 82% and a specificity of 83% for predicting recurrence of AF.