Current strategies in the surgical treatment of atrial fibrillation: review of the literature and Onze Lieve Vrouw Clinic's strategy

Concomitant Cardiac Surgery and Radiofrequency Ablation of Atrial Fibrillation: A Retrospective Single Center Study

OBJECTIVES

Concomitant cardiac surgery and radiofrequency atrial fibrillation (AF) ablation is an established procedure recommended in guidelines. However, the results have not been as good as expected. The authors therefore searched for predictive factors of success of the ablation procedure.

DESIGN

The authors carried out a retrospective cohort study.

SETTING

All the included patients had cardiac surgery in the Dijon University Hospital.

PARTICIPANTS

One hundred sixty-three patients with AF underwent a concomitant radiofrequency ablation between January 2009 and December 2016.

INTERVENTIONS

A radiofrequency device was used to isolate the pulmonary veins creating a "Box lesion."

MEASUREMENTS AND MAIN RESULTS

The primary endpoint of the study was freedom from AF at 12 months with follow-up assessed by an electrocardiogram or a 24-hour recording electrocardiogram Holter. The patient's mean age was 71 ± 9 years with a sex ratio of 1.4. Sixty-six percent of patients had paroxysmal AF and 34% nonparoxysmal AF, which includes persistent and long-standing persistent AF. Sixty-one percent of patients had an AF history for more than 1 year. The mean left atrial diameter was 47 ± 10 mm. No major ablation complications related to the procedure occurred. Overall freedom from AF rate after 1-year follow-up was 60% (n = 98). Six patients (4%) received an additional catheter-based ablation, and 10 patients (6%) had an electrical cardioversion during the follow-up period. The authors identified preoperative paroxysmal AF (odds ratio [OR] 2.54 [1.27-5.14] p = 0.008) and recent history of AF, less than 1 year, (OR 1.99 [1-4.06] p = 0.05) as statistically significant predictors for sinus rhythm maintenance at the 12-month follow-up. At the 12-month follow-up, 64% of patients who had concomitant epicardial treatment were in sinus rhythm and 57% of patients were in sinus rhythm after endocardial treatment. There were no significant differences in rhythm outcome between epicardial and endocardial radiofrequency approach, or between surgical procedures (mitral valve replacement versus coronary artery bypass grafting). The authors could not identify in a univariate analysis a significant left atrium size cutoff upon which ablation was less likely to be successful at 12 months follow-up.

CONCLUSIONS

Concomitant cardiac surgery and radiofrequency AF ablation provided freedom from AF for 60% of patients after 1-year follow-up. The authors have shown that paroxysmal AF and recent AF are predictive factors of success. Nevertheless, thorough postoperative care is necessary to improve long-term results, including the use of additional catheter ablation or cardioversion.

Repair versus replacement of mitral valves in cases of severe rheumatic mitral stenosis: mid-term clinical outcomes

Background

We compared and analyzed differences between repair vs. replacement of mitral valves on severe rheumatic mitral stenosis by looking at mid-term clinical outcomes.

Methods

Patients with severe rheumatic mitral stenosis (mitral valve area ≤1.5 cm², with or without mitral valve regurgitation) from January 2011 to September 2017 were divided into two groups: a mitral valve repair group (MVP) and a mitral valve replacement group (MVR). After propensity score matching between the two groups, we compared changes in post-operation clinical outcomes. We also monitored changes in left ventricular longitudinal and circumferential strain in successfully matched patients (20 pairs) by echocardiography speckle tracing.

Results

A total of 921 patients were recruited (221 in MVP and 700 in MVR). After a propensity score matching, 216 cases were selected with 108 patients in each group. With a follow-up period of 3 months to 7.1 years, the incidence of heart failure was observed to be significantly higher in the MVR group than in the MVP group (P<0.05). Echocardiographic speckle tracking imaging analysis showed that left ventricular longitudinal strain decreased in the MVR group, suggesting that a change of cardiac structure may affect the cardiac function.

Conclusions

Selecting suitable patients for mitral valve repair is feasible even for patients with severe rheumatic mitral stenosis. In our study, compared with prosthetic valve replacement in these patients, valve repair still significantly reduced the valve-related complications rates and improved the quality of life during the follow-up.

Endoscopic atrioventricular valve surgery in adults with difficult-to-access uncorrected congenital chest wall deformities

OBJECTIVES

This study presents the first report on in-hospital and long-term outcomes of endoscopic port access atrioventricular valve surgery (EPAAVVS) in adult patients with uncorrected congenital chest wall deformities (CCWDs).

METHODS

Our current surgical team performed EPAAVVS in 7 consecutive adult patients (mean age 51.3 ± 16.4 years, 14.3% female, 50% older than 60 years, mean EuroSCORE II 0.8 ± 0.1%) with uncorrected CCWDs between 1 November 2009 and 30 November 2015. The mean left ventricular ejection fraction was 66.0 ± 8.5%. Surgical indications included isolated or combined symptomatic mitral valve (MV) regurgitation (n = 7, 100%), left ventricular outflow tract (LVOT) obstruction (n = 1, 14.3%) and patent foramen ovale (n = 3, 42.9%). Fibro-elastic deficiency accounted for 57.1% of MV pathology and 5 patients (74.1%) presented with New York Heart Association (NYHA) Class III symptoms. CCWDs included isolated pectus excavatum (n = 5, 71.4%) and mixed pectus excavatum and carinatum (n = 2, 28.6%). The mean Haller-index and correction index scores were 2.7 ± 0.5 and 21.4 ± 10.2%, respectively.

RESULTS

Procedures performed included MV repair (n = 7, 100%), tricuspid valve (TV) repair (n = 1, 14.3%) and left ventricular septal myomectomy (n = 1, 14.3%). There were no sternotomy conversions or complications with chest wall entry or atrioventricular valve exposure. The mean cardiopulmonary bypass and cross-clamp times were 162.1 ± 48.1 and 113.7 ± 33.5 min, respectively. No patient required mechanical ventilation or intensive care treatment longer than 24 h. There were no surgical revisions, in-hospital respiratory or chest wall morbidities. The mean length of hospital stay was 7.4 ± 1.0 days. A total of 208 patient-months (mean 29.7 ± 26.5) were available for long-term clinical and echocardiographic analysis. There were no 30-day or long-term mortalities and no patient required reintervention for residual atrioventricular valve pathology. All patients were classified as NYHA I during recent consultations, and echocardiographic follow-up confirmed no residual MV regurgitation greater than Grade 1 in any patient.

CONCLUSIONS

EPAAVVS in adults with uncorrected CCWD is safe, feasible and durable and can successfully be performed by experienced teams to achieve Haller index and correction index scores of up to 3.3 and 38.3%, respectively, with favourable long-term clinical and echocardiographic outcomes. The mere presence of uncorrected CCWDs should not deter surgeons from offering these patients the full benefits of minimally invasive cardiac surgery.

Late redo-port access surgery after port access surgery

OBJECTIVES

This study presents the first report on short- and long-term outcomes in redo-port access surgery after previous port access surgery (redo-PAS-PAS) for new or recurrent mitral valve (MV) and tricuspid valve (TV) disease.

METHODS

Our current surgical team performed redo-PAS-PAS in 26 consecutive patients who had previous port access surgery (mean age 65.8 ± 13.3 years, 46.2% female, 42.3% older than 70 years, mean logistical EuroSCORE 22.5 ± 21.6%) between 1 February 1997 and 30 June 2014. Surgical indications included among others MV prosthesis dysfunction (n = 8, 30.8%), endocarditis (n = 10, 38.5%) and TV dysfunction (n = 3, 11.5%). The mean time interval between primary PAS and redo-PAS-PAS was 70.32 ± 57.4 months.

RESULTS

Redo-PAS-PAS procedures included MV replacement (n = 19, 73.1%), MV repair (n = 5, 19.2%), and TV repair (n = 2, 7.7%). Sternotomy conversion was required in 5 patients (19.2%), of which 4 (15.4%) were early conversions due to lung adhesion and 1 (3.8%) due to a late intraoperative complication. The mean cardiopulmonary bypass and cross-clamp times were 163.3 ± 57.9 and 101.2 ± 43.8 min, respectively. Postoperative mechanical ventilation longer than 72 h was required in 4 patients (15.4%). In-hospital morbidities included hospital-acquired pneumonia (n = 3, 11.5%), postoperative air leaks (n = 2, 7.7%) and revision for bleeding (n = 1, 3.8%). The mean length of hospital stay was 16.1 days. Long-term clinical and echocardiographic follow-up were 48.3 ± 39.2 and 44.6 ± 32.9 months, respectively. The Kaplan-Meier analyses for survival and freedom from mitral and tricuspid valve reintervention (n = 26) at 5 years were 83.9 and 95.8%, respectively, with 91.3% of surviving patients classified as being NYHA II or less. Echocardiographic follow-up showed no residual mitral regurgitation more than grade I in all redo mitral valve repairs and no paravalvular leak post-valve replacement.

CONCLUSIONS

Redo-PAS-PAS is our routine approach and we apply this strategy in the majority of patients who had previous port access surgery. The predicted procedure-related mortality, morbidities, patient satisfaction and long-term outcomes are favourable.

Surgical Treatment of Concomitant Atrial Fibrillation: Focus onto Atrial Contractility

BACKGROUND

Maze procedure aims at restoring sinus rhythm (SR) and atrial contractility (AC). This study evaluated multiple aspects of AC recovery and their relationship with SR regain after ablation.

METHODS

122 mitral and fibrillating patients underwent radiofrequency Maze. Rhythm check and echocardiographic control of biatrial contractility were performed at 3, 6, 12, and 24 months postoperatively. A multivariate Cox analysis of risk factors for absence of AC recuperation was applied.

RESULTS

At 2-years follow-up, SR was achieved in 79% of patients. SR-AC coexistence increased from 76% until 98%, while biatrial contraction detection augmented from 84 to 98% at late stage. Shorter preoperative arrhythmia duration was the only common predictor of SR-AC restoring, while pulmonary artery pressure (PAP) negatively influenced AC recuperation. Early AC restoration favored future freedom from arrhythmia recurrence. Minor LA dimensions correlated with improved future A/E value and vice versa. Right atrial (RA) contractility restoring favored better left ventricular (LV) performance and volumes.

CONCLUSIONS

SR and left AC are two interrelated Maze objectives. Factors associated with arrhythmia "chronic state" (PAP and arrhythmia duration) are negative predictors of procedural success. Our results suggest an association between postoperative LA dimensions and "kick" restoring and an influence of RA contraction onto LV function.

The Role of BNP and CRP in Predicting the Development of Atrial Fibrillation in Patients Undergoing Isolated Coronary Artery Bypass Surgery

Objective. To evaluate the association of BNP and CRP with the development of postoperative atrial fibrillation following coronary artery bypass grafting surgery. Methods. The series consists of 125 patients (aged 65 ± 9 years), who underwent isolated CABG-surgery. BNP and CRP levels were measured pre- and 24 hours postoperatively and their correlation to the development of postoperative AF was analyzed. Results. Forty-four patients (35%) developed AF postoperatively. They were significantly older (68 ± 8 versus 63 ± 9, P = 0.01) and predominantly nonsmokers (18% versus 46%, P = 0.004), compared to the non-AF cases. In addition they showed significant higher preoperative mean BNP levels of 629 versus 373 pg/mL (P = 0.019). Postoperative BNP levels were significantly higher in both groups (AF-group: 1032 pg/mL versus non-AF group: 705 pg/mL; P < 0.001), while there was a trend of more increased postoperative levels in AF-cases (P = 0.065). AF-episodes appeared significantly more frequent in the two highest quartiles of BNP levels with 44% (P = 0.035). On the contrary pre- and postoperative CRP levels were not associated with AF. Multivariable analysis revealed only increased preoperative BNP levels as independent predictor for postoperative AF (P = 0.036). Conclusion. Elevated preoperative BNP serum levels are associated with the development of post-CABG AF, while CRP does not seem to be influential.

Combined resection and radiofrequency ablation of rhabdomyoma in a child with sustained ventricular tachycardia

Cardiac rhabdomyoma is a benign tumor of the heart in childhood and can be associated with life-threatening arrhythmia. In this report, we present the case of a 2-year-old male with right ventricular rhabdomyoma, who was admitted with syncope that was associated with episodes of sustained ventricular tachycardia. The patient underwent combined surgical resection and radiofrequency ablation of the tumor. There was no recurrence of ventricular tachycardia after surgery.

Feasibility of in vivo transesophageal cardiac ablation using a phased ultrasound array

Over 2.2 million Americans suffer from atrial fibrillation making it one of the most common arrhythmias. Cardiac ablation has shown a high rate of success in treating paroxysmal atrial fibrillation. Prevailing modalities for this treatment are catheter based radio-frequency ablation or surgery. However, there is measurable morbidity and significant costs and time associated with these invasive procedures. Due to these issues, developing a method that is less invasive to treat atrial fibrillation is needed. In the development of such a device, a transesophageal ultrasound applicator for cardiac ablation was designed, constructed and evaluated. A goal of this research was to create lesions in myocardial tissue using a phased array. Based on multiple factors from array simulations, transesophageal imaging devices and throat anatomy, a phased ultrasound transducer that can be inserted into the esophagus was designed and tested. In this research, a two-dimensional sparse phased array with the aperture size of 20.7 mm x 10.2 mm with flat tapered elements as a transesophageal ultrasound applicator was fabricated and evaluated with in vivo experiments. Five pigs were anesthetized; the array was passed through the esophagus and positioned over the heart. The array was operated for 8-15 min at 1.6 MHz with the acoustic intensity of 150-300 W/cm(2) resulting in both single and multiple lesions on atrial and ventricular myocardium. The average size of lesions was 5.1 +/- 2.1 mm in diameter and 7.8 +/- 2.5 mm in length. Based on the experimental results, the array delivered sufficient power to the focal point to produce ablation while not grossly damaging nearby tissue outside the target area. These results demonstrate a potential application of the ultrasound applicator to transesophageal cardiac surgery in atrial fibrillation treatment.

Epicardial Catheter Ablation of Atrial Fibrillation

Atrial fibrillation (AF) can cause significant symptoms despite control of ventricular rate, and for some patients a rhythm-control strategy is more appropriate. Because antiarrhythmic drugs have limited efficacy for treating AF and can cause significant side effects, nonpharmacologic therapy has found a growing role in the treatment of this arrhythmia. While endocardial catheter ablation has shown superior results over drug therapy, long-term clinical outcomes are still disappointing, especially for persistent AF. This article discusses percutaneous epicardial catheter ablation, the rationale for using this approach to treat AF, anatomy relevant to the approach, challenges in performing such procedures, and finally, the potential future directions in this promising new field.

Microwave tissue ablation: biophysics, technology, and applications

Microwave ablation is an emerging treatment option for many cancers, cardiac arrhythmias, and other medical conditions. During treatment, microwaves are applied directly to tissues to produce rapid temperature elevations sufficient to produce immediate coagulative necrosis. The engineering design criteria for each application differ, with individual consideration for factors such as desired ablation zone size, treatment duration, and procedural invasiveness. Recent technological developments in applicator cooling, power control, and system optimization for specific applications promise to increase the utilization of microwave ablation in the future. This article reviews the basic biophysics of microwave tissue heating, provides an overview of the design and operation of current equipment, and outlines areas for future research.

Atrial function after ablation procedure in patients with chronic atrial fibrillation using steady-state free precession magnetic resonance imaging

BACKGROUND

Surgical ablation procedures are an established surgical procedure for restoration of sinus rhythm and reestablishment of atrial function in patients with chronic atrial fibrillation. The purpose of this study was to evaluate the feasibility and reproducibility of steady-state free precession magnetic resonance imaging (SSFP MRI) for examination of atrial dimensions and function after ablation procedures.

METHODS

Nineteen patients (mean age, 63.1 +/- 11.7 years) being at least six months after surgical ablation procedure, with stable sinus rhythm, were selected for the study. They underwent cardiac MRI. End-diastolic and end-systolic volumes were measured using Simpson's rule. The presence of visual contraction was visually assessed.

RESULTS

In MRI evaluation mean end-diastolic volume of the right atrium and left atrium after an ablation procedure was 127 +/- 45 mL and 163 +/- 50 mL, respectively. Mean stroke volume was 23 +/- 15 mL and 26 +/- 12 mL for the right and left atrium. Mean ejection fraction of the right atrium was 0.19 +/- 0.14 and 0.17 +/- 0.1 for the left atrium. An atrial kick of both atria was observed in 8 of 19 (47%) patients. An atrial kick of only the right atrium was observed in an additional 13 of 19 (68%) patients.

CONCLUSIONS

The anticipated events after a surgical ablation procedure are the restoration of atrial contractility and the associated atrial kick, thereby enhancing cardiac output and decreasing the risk of thromboembolism. Evaluation of atrial function after an ablation procedure using SSFP MRI is feasible and allows a standardized documentation of postoperative atrial function, thus allowing evaluation of the surgical outcome in a reproducible way. Echocardiographic evaluation seems to underestimate the transport function of the atrium.

The multi–purse string maze procedure: A new surgical technique to perform the full maze procedure without atriotomies

OBJECTIVE

The maze procedure is the most effective surgical procedure for atrial fibrillation. In recent years, a number of different surgical ablation devices were introduced and gradually replaced the need for the procedure to be performed by using the cut-and-sew technique. In this article a new surgical approach is presented using a full maze IV lesion set, without atriotomies.

METHODS

Between January 2005 and June 2006, 12 patients underwent operations with the multi-purse string technique: 9 patients as a combined procedure with coronary artery bypass grafting, 2 patients as a combined procedure with aortic valve replacement, and 1 patient as a standalone procedure. In 5 additional patients, a small left atrial atriotomy was required to ensure the completeness of the mitral valve isthmus lesion. A combination of bipolar radiofrequency and cryothermal energies was used in all cases. All patients were part of our comprehensive follow-up and local atrial fibrillation registry.

RESULTS

No perioperative morality, cerebrovascular accidents/transient ischemic attacks, or both were documented in this series. In a mean follow-up of 13 +/- 6 months, 1 late death was documented, and 91% of the patients are free from atrial fibrillation or flutter.

CONCLUSIONS

Our experience suggests that the maze IV procedure can be performed without the need for atriotomies by using the multi-purse string approach. The intermediate results are promising, with high rates of success in ablating atrial fibrillation. Future studies should be performed to validate the safety of the use of bipolar radiofrequency devices endocardially on a beating heart.