Mitral regurgitation attenuates thrombotic risk in nonrheumatic atrial fibrillation: a new CHA2DS2-VASc score risk modifier?

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction: Atrial fibrillation (AF) carries a thrombotic risk related to left atrial blood stasis. Many risk scores, such as the CHA2DS2-VASc score, have been developed to guide physicians in initiating anticoagulant therapy. However, the risk prediction with these models is modest at best (C-statistic = 0.6). The presence of mitral regurgitation (MR) has been shown to reduce thrombotic risk in patients with rheumatic AF. In nonrheumatic AF, direct evidence of a lower thrombotic risk in patients with MR is still controversial.

Purpose

The current study assessed the effect of MR on thrombotic risk in nonrheumatic AF patients.

Methods

The prevalence of atrial thrombosis, defined as the presence of left atrial appendage thrombus (LAAT) and/or left atrial spontaneous echo contrast (LASEC) grade >2, was determined in 686 consecutive nonrheumatic AF patients without (adequate) anticoagulation scheduled for transoesophageal echocardiography before electrical cardioversion and was related to the severity of MR adjusted for the CHA2DS2-VASc score. The independent predictors of atrial thrombosis were assessed by stepwise multiple logistic regression analysis.

Results

A total of 103 (15%) patients had severe MR, 210 (31%) had moderate MR, and 373 (54%) had no-mild MR; the median CHA2DS2-VASc score was 3.0 (IQR 2.0-4.0). Atrial thrombosis (LAAT and/or LASEC grade >2) was observed in 118 patients (17%). The prevalence of atrial thrombosis decreased with increasing MR severity: 19.9% versus 15.2% versus 11.6% for no-mild, moderate, and severe MR, respectively (p for trend = 0.03) (Figure 1). Patients with moderate and severe MR had a lower risk of atrial thrombosis than patients with no-mild MR, with adjusted odds ratios (ORs) of 0.51 (95% CI 0.31-0.84) and 0.24 (95% CI 0.11-0.49), respectively. The other independent predictors of atrial thrombosis were: the CHA2DS2-VASc score with an adjusted OR of 1.25 (95% CI 1.10-1.42), poor left ventricular ejection fraction (LVEF, <40%) with an adjusted OR of 4.08 (95% CI 2.56-6.50), and large left atrial volume index (LAVI, >37 ml/m²) with an adjusted OR of 1.90 (95% CI 1.19-3.03) (Figure 1, upper right corner). The C-statistic of the regression model increased significantly (p = 0.0003) from 0.62 to 0.75 by adding MR grade, LVEF, and LAVI to the univariate CHA2DS2-VASc score model. The protective effect of MR was present across all levels of the CHA2DS2-VASc score and the presence of moderate-severe MR in patients with an intermediate CHA2DS2-VASc score (2-3) lowered the atrial thrombotic risk to the level of patients with a low CHA2DS2-VASc score (0-1).

Conclusion

Our data show that the presence of MR attenuated the atrial thrombotic risk by more than 50% in patients with nonrheumatic AF, independent of the CHA2DS2-VASc risk score. Moderate to severe MR can therefore be considered a new risk modifier of the CHA2DS2-VASc score, which might help refine the indication of anticoagulants in AF patients. Abstract Figure 1. Thrombotic risk per MR grade.

P1878Long-term effect of atrial fibrillation on the evolution of mitral and tricuspid valve regurgitation

Background

While severe mitral regurgitation is a well-established risk factor for atrial fibrillation (AF), it is less known whether atrial fibrillation induces mitral/tricuspid valve regurgitation (MR/TR). The present study aims to identify the long-term effects of permanent or non-permanent AF on atrial remodelling and on the progression of MR/TR.

Methods

The severity of MR/TR was assessed at baseline and after a period of 65±10 months in 37 patients with permanent AF, in 80 patients with non-permanent AF (of whom 43 were treated with ablation) and in 53 control patients with persistent sinus rhythm. MR/TR was qualitatively assessed by the multi-integrative approach, and quantitatively by measurement of the colour jet area.

Results

At baseline, AF patients had larger MR jet areas than control patients. At follow up, progression of MR, expressed as delta MR jet area, was 0.05±1.3 cm2 in the control group, 0.73±2.1 cm2 in the non-permanent AF group and 1.95±3.6 cm2 in the permanent AF group (p=0.001). Severe MR at follow up was observed in 0%, 2.5%, 8%, respectively. After adjustment for baseline clinical and echocardiographic parameters, permanent AF remained independently associated with the progression of MR. There was a significant positive correlation between a progression of MR and an increase in left atrial volume index (r=0.31, p<0.001). Although rhythm control in non-permanent AF patients was better with AF ablation than with medical treatment only, the MR evolution was similar (delta MR jet area: 0.85±2.05 cm2 vs 0.61±2.12 cm2, p=0.6). Comparable findings, albeit less pronounced, were observed for the association between of AF and TR progression.

MR jet area

Conclusions

The presence of longstanding AF is associated with a significant progression of MR/TR mainly due to atrial remodelling. Our data showed a beneficial effect of sustained rhythm control, either medically or by ablation, on MR/TR progression.

Long-term effect of atrial fibrillation on the evolution of mitral and tricuspid valve regurgitation

Objective: The present study aims to identify the long-term effects of atrial fibrillation (AF) on atrial remodelling and on the progression of mitral/tricuspid valve regurgitation (MR/TR). Methods: The severity of MR/TR was assessed by the colour jet area and by multi-integrative approach at baseline and after a period of 65 ± 10 months in 37 patients with permanent AF, in 80 patients with non-permanent AF (of whom 43 were treated with ablation) and in 53 control patients with sinus rhythm. Results: At baseline, AF patients had larger MR jet areas than control patients. At follow up, progression of MR, expressed as delta MR jet area, was 0.05 ± 1.3 cm² in the control group, 0.73 ± 2.1 cm² in the non-permanent AF group and 1.95 ± 3.6 cm² in the permanent AF group (p = .001). Severe MR at follow up was observed in 0%, 2.5%, 8%, respectively. There was a significant positive correlation between progression of MR and increase of left atrium volume (r = 0.31, p < .001). After adjustment for baseline clinical and echocardiographic parameters, permanent AF remained independently associated with the progression of MR. Although rhythm control was better with AF ablation than with medical treatment only, the MR evolution was similar. Comparable findings, albeit less pronounced, were observed for the association between of AF and TR progression. Conclusions: The presence of longstanding AF is associated with a significant progression of MR/TR mainly due to atrial remodelling. Our data showed a beneficial effect of sustained rhythm control, either medically or by ablation, on MR/TR progression.

Elective Wiktor GX stenting for symptomatic stenosis in old aortocoronary saphenous vein bypass grafts: the Antwerp experience

PURPOSE

We compared initial outcome, peri-procedural complications and long-term clinical follow-up of elective Wiktor GX stent implantation in severely narrowed vein grafts to a historic register of elective angioplasties in saphenous vein grafts in the same center.

METHODS

Eighty-one consecutive patients with angina and a history of coronary artery bypass grafting (CABG), all received elective angioplasty (PTCA) of the diseased graft; we described them as group P. The next 38 consecutive patients were treated with elective angioplasty and Wiktor Stent implantation, followed by one month ticlopidine; they were called group S.

CONCLUSION

This retrospective study suggests that elective Wiktor stenting in old saphenous vein graft stenosis, in combination with one month ticlopidine, leads to: 1) a better angiographic result, with reduction of peri-procedural complications; and 2) a lower incidence of recurrent angina, need for invasive or surgical re-intervention, myocardial infarction and death during follow-up.

Cardiac graft vasculopathy: aetiologic factors and therapeutic approaches

Heart transplantation has become an accepted and successful treatment for end-stage heart disease with survival rates of 80-90% after one year and 70% after 5 years. During the early posttransplant period (6-12 months), patients are subject to two major complications: rejection and infection. Fortunately, a certain degree of graft tolerance develops, allowing the immunosuppressive therapy to be progressively tapered off with a concomitant decrease in infectious problems. Long-term survival, however, is largely dependent on the development of an accelerated atherosclerosis in the graft, which is believed to represent some kind of chronic rejection. This transplant vasculopathy is documented by means of coronary angiography with an incidence of approximately 5 to 10% per year. It is not surprising therefore that major interest has risen concerning risk factors promoting this pathology.

External vibration interference of activity based rate responsive pacemakers

The change of the pacing rate in response to external vibration interference was assessed in four rate responsive pacemakers with a piezoelectric crystal (Medtronic Activitrax 8403, Siemens Sensolog 3, Biotronik Ergos 01, and Medtronic Legend 8417) and one with an accelerometer (CPI Excel VR 1119). They were tested in the laboratory. External vibration was simulated in vitro by exposing the different pacemakers to a controlled sinusoidal vibration force generated by a Millar pressure vibration amplifier type MGM-30 (Millar Instruments, Inc., Houston, TX, USA). All pacemakers were programmed at standard settings. Two types of vibration forces were applied: (1) one with varying amplitude but with constant vibration frequency; and (2) one with varying frequency but with constant vibration amplitude. In this manner curves of pacing rate versus vibration forces versus vibration frequency were obtained. High vibration forces and low vibration frequencies were associated with the highest pacing rate response. In this experimental setting, the pacemaker based on the accelerometer principle apparently was the least sensitive to high frequency vibrations, which are known to be related to environmental interference. It also seemed more appropriately responsive in the lower frequency range, which is more appropriate for the detection of true physiological activity.

[P wave changes and atrial fibrillation after implantation of VVI type pacemaker]

The P waves of patients with VVI pacemakers were compared with those of DDD pacemakers at implantation and then regularly for 5 years. A certain number of cardiac pathologies are known to cause P wave changes. The incidence of atrial fibrillation (AF) was much higher in VVI than in DDD patients. In the VVI group, the incidence was much greater in patients paced for sinus node disease than in patients paced for AVB. Analysis of sinus P wave characteristics in 320 patients with VVI pacemakers shows progressive abnormalities of atrial function with time. The expression of this atrial dysfunction is a statistically significant prolongation of the P wave in V1 and dII and of the terminal part of the P wave in V1. The factors responsible for this abnormality and which favours the occurrence of AF are quasi-permanent pacing, the presence of retrograde conduction and an abnormality of atrial activation at the time of implantation.

Evolution of P wave characteristics after pacemaker implantation

This study is an investigation of the long-term effects of VVI pacing on the atrium as derived from the evolution of P wave characteristics of 285 patients. The occurrence of left and right atrial disease is demonstrated as well as the evolution of left atrial hypertrophy in some cases. A comparison is made with DDD pacing and special attention is given to the progression to atrial fibrillation.