Amaze: a randomized controlled trial of adjunct surgery for atrial fibrillation.

OBJECTIVES: Atrial fibrillation (AF) reduces survival and quality of life (QoL). It can be treated at the time of major cardiac surgery using ablation procedures ranging from simple pulmonary vein isolation to a full maze procedure. The aim of this study is to evaluate the impact of adjunct AF surgery as currently performed on sinus rhythm (SR) restoration, survival, QoL and cost-effectiveness. METHODS: In a multicentre, Phase III, pragmatic, double-blinded, parallel-armed randomized controlled trial, 352 cardiac surgery patients with >3 months of documented AF were randomized to surgery with or without adjunct maze or similar AF ablation between 2009 and 2014. Primary outcomes were SR restoration at 1 year and quality-adjusted life years at 2 years. Secondary outcomes included SR at 2 years, overall and stroke-free survival, medication, QoL, cost-effectiveness and safety. RESULTS: More ablation patients were in SR at 1 year [odds ratio (OR) 2.06, 95% confidence interval (CI) 1.20-3.54; P = 0.009]. At 2 years, the OR increased to 3.24 (95% CI 1.76-5.96). Quality-adjusted life years were similar at 2 years (ablation - control -0.025, P = 0.6319). Significantly fewer ablation patients were anticoagulated from 6 months postoperatively. Stroke rates were 5.7% (ablation) and 9.1% (control) (P = 0.3083). There was no significant difference in stroke-free survival [hazard ratio (HR) = 0.99, 95% CI 0.64-1.53; P = 0.949] nor in serious adverse events, operative or overall survival, cardioversion, pacemaker implantation, New York Heart Association, EQ-5D-3L and SF-36. The mean additional ablation cost per patient was £3533 (95% CI £1321-£5746). Cost-effectiveness was not demonstrated at 2 years. CONCLUSIONS: Adjunct AF surgery is safe and increases SR restoration and costs but not survival or QoL up to 2 years. A continued follow-up will provide information on these outcomes in the longer term. Study registration: ISRCTN82731440 (project number 07/01/34).

Management of superior vena cava obstruction syndrome due to thrombosis of a Contegra conduit used to re-establish the innominate vein-to-right atrium continuity.

Following intraoperative superior vena cava injury, venous drainage of the head, neck and upper extremities can be re-established with bovine jugular vein (Contegra) conduits. Inadequate anticoagulation, however, may lead to conduit thrombosis and superior vena cava obstruction syndrome. This can be successfully treated with percutaneous dilatation and stenting of the failed conduit.

The effect of preoperative atrial fibrillation on survival following mitral valve repair for degenerative mitral regurgitation.

OBJECTIVE: There is conflicting evidence with regard to the impact of preoperative atrial fibrillation (AF) on the post mitral valve (MV) repair on the early and late outcome. METHODS: A total of 349 patients undergoing various MV repair procedures for degenerative mitral regurgitation (MR) between 1997 and 2003 were studied. Preoperatively, 152 (44%) of these patients were in AF and 197 (56%) patients were in sinus rhythm (SR). The clinical features and the outcome in these two cohorts of patients were compared. RESULTS: The patients in the AF group were older than their counterparts in the SR group (66+/-7 vs 62+/-9 years) (p=0.01), had a higher mean NYHA class score (2.4+/-0.6 vs 2.2+/-0.7) (p=0.04) and were more likely to have impaired left ventricular function (60% vs 36%) (p<0.0001). A similar proportion of patients in the AF (38%) and SR (30%) groups had additional cardiac surgical procedures (p=0.12). Operative mortality was 3.9% in AF group versus 0.5% in SR group (p=0.04), and operative morbidity was 27% versus 17%, respectively (p=0.03). At latest follow up, 4% of patients that were in SR preoperatively developed AF; conversely, 2% of the patients in the AF group converted to SR. The rates of recurrent grade II or III MR (4% vs 5%) (p=0.8) and MV re-operation (2.6% vs 2.5%) (p=1.0) were similar in the AF and SR groups. Kaplan-Meier survival at 7 years was 75+/-6% versus 90+/-3% (p=0.005). On Cox proportional hazards regression model, impaired LV function [(p=0.02), hazard ratio 0.25 (95% confidence intervals (C.I.) 0.078-0.84)] and AF [(p=0.03), hazard ratio 2.70 (95% C.I. 1.09-6.68)] were significant adverse predictors of survival. CONCLUSIONS: This study shows that in patients undergoing MV repair for degenerative MR, preoperative AF has a major negative impact on the early and late survival.

Left atrial radiofrequency ablation during mitral valve surgery for continuous atrial fibrillation: a randomized controlled trial.

CONTEXT: Although left atrial radiofrequency ablation (RFA) is increasingly used for the treatment of chronic atrial fibrillation during mitral valve surgery, its efficacy to restore sinus rhythm and any resulting benefits have not been examined in the context of an adequately powered randomized trial. OBJECTIVE: To determine whether intraoperative RFA of the left atrium increases the long-term restoration of sinus rhythm and improves exercise capacity. DESIGN, SETTING, AND PATIENTS: Randomized, double-blind trial performed in a single UK tertiary referral center with enrollment between December 2001 and November 2003. A total of 101 patients referred for mitral valve surgery with at least 6 months' history of uninterrupted atrial fibrillation were assessed for eligibility; 97 were enrolled. Patients were followed up for 12 months. INTERVENTION: Patients were randomly assigned to undergo mitral valve surgery and RFA of the left atrium (n = 49) or mitral valve surgery alone (controls; n = 48). MAIN OUTCOME MEASURES: The primary outcome measure was presence of sinus rhythm at 12 months; secondary measures were patient functional status and exercise capacity (assessed by shuttle-walk test), left atrial contractility, and left atrial and left ventricular dimension and function and plasma levels of B-type natriuretic peptide. RESULTS: At 12 months, sinus rhythm was present in 20 (44.4%) of 45 RFA patients and in 2 (4.5%) of 44 controls (rate ratio, 9.8; 95% CI, 2.4-86.3; P<.001). Restoration of sinus rhythm in the RFA group was accompanied by a greater improvement in mean (SD) shuttle-walk distance compared with controls (+94 [102] m vs +48 [82] m; P = .003) and a greater reduction in the plasma level of B-type natriuretic peptide (-104 [87] fmol/mL vs -51 [82] fmol/mL; P = .03). Patients randomized to receive RFA had similar rates of postoperative complications and deaths as control patients. CONCLUSIONS: Radiofrequency ablation of the left atrium during mitral valve surgery for continuous atrial fibrillation significantly increases the rate of sinus rhythm restoration 1 year postoperatively, improving patient exercise capacity. On the basis of its efficacy and safety, routine use of RFA of the left atrium during mitral valve surgery may be justified. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00238706.

Edge-to-edge repair with mitral annuloplasty for Barlow's disease.

BACKGROUND: The purpose of this study was to define the early and midterm results obtained after the use of edge-to-edge repair with mitral annuloplasty in the setting of Barlow's disease. METHODS: Between 1998 and 2004, 41 patients having Barlow's disease had an edge-to-edge repair creating a double-lumen mitral valve orifice in our unit. In 38 patients (93%), an annuloplasty band was also inserted. RESULTS: Preoperatively, all patients had severe mitral regurgitation (MR), 12 were in New York Heart Association (NYHA) class I, 15 in class II, and 14 in class III. One patient died in hospital (2.4%) and 5 experienced complications (12.5%). There were no late deaths. At follow-up, 2 patients had severe MR and underwent valve replacement, 1 exhibited moderate MR, and 5 had mild MR. Kaplan-Meier 5-year survival, freedom from reoperation and recurrent moderate-severe MR was 97.6% +/- 2.4%, 94% +/- 4.4%, and 90.6% +/- 5.1%, respectively. At latest echocardiographic evaluation (mean 35 +/- 12 months) the mean left ventricular end-systolic and end-diastolic diameters, and the mitral valve area decreased (p = 0.0001) compared with baseline. The mean mitral valve gradient increased (p = 0.001) without clinical evidence of mitral stenosis whereas ejection fraction did not change. Currently, 35 patients are in NYHA class I and 5 are in class II. CONCLUSIONS: In the setting of Barlow's disease, use of edge-to-edge repair with mitral annuloplasty is safe and provides lasting restoration of mitral valve competence with measurable hemodynamic and clinical benefits. In our unit, it is the procedure of choice for correction of MR in patients having Barlow's disease.

Skeletonization of internal thoracic artery affects its innervation and reactivity.

OBJECTIVE: The studies showing the superior characteristics of ITA graft and its impact on the clinical results of coronary artery surgery were performed with ITA harvested almost exclusively as a pedicle. This study assesses the impact of ITA skeletonization on its innervation and reactivity. METHODS: Segments of skeletonized and non-skeletonized ITA were stained with antibodies against protein S-100 to look for the presence of sympathetic nerve fibers. The functional studies were performed on segments of discarded human pedicled ITA that were divided into two 3mm rings, one skeletonized and another non-skeletonized. We compared concentration-effect relationships for the contraction to norepinephrine and endothelium-dependent relaxation to acetylcholine and bradykinin, as well as endothelium-independent relaxation to sodium nitroprusside in skeletonized and non-skeletonized segments of the same ITA. RESULTS: Skeletonized ITA was devoid of protein S-100 positive nerve fibers. It contracted stronger (maximal response 37.0+/-2.04 vs. 25.4+/-1.83mN (P<0.001)) and was twice as sensitive to norepinephrine: pD(2) 6.03+/-0.10 vs. 5.70+/-0.12 (P=0.035). The endothelium-dependent relaxation responses did not differ between skeletonized and non-skeletonized ITA rings. The skeletonized ITA rings appeared over 10 times more sensitive to sodium nitroprusside: pD(2) 6.66+/-0.20 vs. 5.59+/-0.37 (P=0.012)-potency ratio 11.61. The maximal responses did not differ significantly: 112.0+/-6.71 vs. 129.4+/-16.4% (P=0.33). CONCLUSIONS: Skeletonization results in sympathectomy of ITA. It has no effect on endothelium-dependent relaxation but increases reactivity of ITA to norepinephrine. This augmented response to alpha-agonist is small, in comparison with over a ten-fold increase in sensitivity to sodium nitroprusside. Pedicled and skeletonized ITA are functionally significantly different vessels when studied in vitro.

Effect of training in mitral valve repair surgery on the early and late outcome.

BACKGROUND: Preservation of the native mitral valve provides important advantages over valve replacement. The aim of this study was to evaluate the effect of training for mitral valve repair on the outcome. METHODS: Between 1997 and 2004, 471 patients underwent mitral valve repair procedures in a single firm. Of these procedures, 300 (64%) were performed by a consultant (TJS) (consultant group) and 171 (36%) by trainees supervised by the same consultant (trainees group). RESULTS: Atrial fibrillation was more prevalent in the consultant group (p = 0.02) but there were no significant differences in the demographics, etiology of mitral regurgitation, and other comorbidity between the groups. Posterior leaflet prolapse was more prevalent in the trainees group (p < 0.0001) and anterior leaflet prolapse (p < 0.0001), bileaflet prolapse (p = 0.003), and Barlow's syndrome (p = 0.0003) in the consultant group. The consultant performed a higher proportion of concomitant coronary artery bypass grafting (p = 0.04), aortic valve replacement (p = 0.02), procedures, and nonelective cases (p = 0.03) with shorter bypass (p = 0.01) and ischemic times (p = 0.0004) than trainees. The complication rate was similar in the two groups (26% vs 22%), but the consultant had a higher operative mortality than the trainees (5% vs 0.6%) (p = 0.01). A similar proportion in the two groups exhibited recurrent mitral regurgitation (8% vs 9%). Kaplan-Meier five-year freedom from reoperation (95.6 +/- 1.6 vs 95.7 +/- 2.2%) (p = 0.7) and survival (82 +/- 4% vs 88 +/- 4%) (p = 0.09) were similar in the two groups. CONCLUSIONS: With appropriate patient selection, cardiothoracic trainees can be taught mitral valve repair surgery without a negative effect on the early or late outcome.

Early hemofiltration improves survival in post-cardiotomy patients with acute renal failure.

OBJECTIVE: The application and timing of hemofiltration (continuous veno-venous hemofiltration, CVVH) in patients with acute renal failure (ARF) post cardiac surgery has been called into question because of uncertain short-term outcome. The aim of the present study was to identify how the timing of introduction of hemofiltration affects the morbidity and mortality in patients with ARF after cardiac surgery. METHODS: 1264 consecutive patients who underwent adult cardiac surgical procedures performed between January 2002 and January 2003 were audited. Out of these, case notes of 64 patients who required renal supportive intervention were reviewed. Statistical significance was accepted at a level of P<0.05. RESULTS: Of the 64 (5%) patients, who developed ARF and required CVVH, there were 48 males and 16 females. Mean age was 70+/-6.8 years. The hospital mortality was 43% (12 patients) in Group-I and 22% (8) in Group-II (P<0.05), giving an overall 1.5% mortality associated with ARF. The mean time between the operation and the initiation of CVVH was 2.55+/-2.2 days in Group-I and 0.78+/-0.2 days in Group-II (P<0.001). The mean duration of CVVH was 4.57+/-11.4 days in Group-I and 4.61+/-2.0 days in Group-II (P=NS). Older age (P=0.013), elevated preoperative creatinine (P=0.002), postoperative pulmonary oedema (P=0.01), sepsis (P=0.001), multiple organ failure (P=0.031), hypotension (P=0.031) and preoperative renal failure (P<0.05) were the independent factors influencing the poor postoperative outcome and cardiac instability. CONCLUSION: Early and aggressive use of CVVH is associated with better than expected survival in severe ARF after cardiac operations.