Deborah J. Shuman

A systematic review of minimally invasive surgical treatment for atrial fibrillation: a comparison of the Cox-Maze procedure, beating-heart epicardial ablation, and the hybrid procedure on safety and efficacy.

There is a growing trend to perform off-bypass surgical ablation for atrial fibrillation (AF) because it is perceived to be safer and more effective than the Cox-Maze procedure with cardiopulmonary bypass (CPB) support. In this systematic review, we compared three minimally invasive stand-alone surgical ablation procedures for AF: the endocardial Cox-Maze procedure, epicardial surgical ablation and a hybrid epicardial surgical and catheter-based endocardial ablation procedure (hybrid procedure). Relevant studies were identified in MEDLINE and the Cochrane Database of Systematic Reviews according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. From 565 initial studies, 37 were included in this review. The total number of patients across all studies was 1877 (range 10-139). Two studies reported on endocardial Cox-Maze procedures (n = 145), 26 reported on epicardial surgical ablation (n = 1382) and 9 reported on hybrid surgical ablation (n = 350). For minimally invasive Cox-Maze, epicardial and hybrid groups, operative mortality rates were 0, 0.5 and 0.9%, perioperative permanent pacemaker insertion rates were 3.5, 2.7 and 1.5%, incidence of conversion to median sternotomy was 0, 2.4 and 2.5%, and reoperation for bleeding was 1.0, 1.5 and 2.2%, with mean length of stay (days) of 5.4, 6.0 and 4.6, respectively. At 12 months, rates of sinus rhythm restoration were 93, 80 and 70%, and sinus restoration without anti-arrhythmic medications was 87, 72 and 71%, for Cox-Maze, epicardial and hybrid procedures, respectively. Of the three procedures, the minimally invasive Cox-Maze procedure with CPB support was most effective for the treatment of stand-alone AF and had important safety advantages in conversion to sternotomy and major bleeding. The minimally invasive Cox-Maze procedure with CPB support also demonstrated the potential for a higher success rate 12 months following the procedure.

Association of operative risk with the outcome of concomitant Cox Maze procedure: A comparison of results across risk groups

OBJECTIVES Cardiac surgery patients with atrial fibrillation face increased risks for perioperative morbidity and decreased survival, yet only 39% of patients presenting with atrial fibrillation undergo concomitant surgical ablation. This low percentage may relate to the perception of lower yield for surgical ablation, especially in patients with complex clinical presentations. In this study, we compared outcomes after a concomitant Cox maze III/IV procedure in patients with high, intermediate, and low predicted operative risk. METHODS Outcome data were prospectively captured after surgery. The additive European System for Cardiac Operative Risk Evaluation (EuroSCORE) was greater than 6 for high-risk patients (n = 145), 3 or less for low-risk patients (n = 76), and greater than 3 and 6 or less for intermediate-risk patients (n = 149). RESULTS No differences were found for perioperative morbidities, including operative mortality (high vs low risk, 2% vs 1%, P = 1.00; high vs intermediate risk, 2% vs 0.7%, P = .37). Median length of stay was longer in high-risk patients versus low-risk patients (8 vs 5 days, P < .001) and intermediate-risk patients (8 vs 6 days, P < .001). Return to sinus rhythm was comparable for high-risk versus low- and intermediate-risk patients at 6, 12, and 24 months. Physical health-related quality of life scores improved similarly for all groups at 12 months. No difference in long-term survival was found (log rank = 0.40; P = .82). CONCLUSIONS The Cox maze III/IV procedure can be performed safely and effectively in patients with higher operative risk, who fare well when compared with lower-risk patients. The Cox maze III/IV procedure should be considered carefully in patients with a significant history of atrial fibrillation.

Effect of patient age on blood product transfusion after cardiac surgery.

OBJECTIVE Blood product transfusion after cardiac surgery is associated with increased morbidity and mortality. Transfusion thresholds are often lower for the elderly, despite the lack of clinical evidence for this practice. This study examined the role of age as a predictor for blood transfusion. METHODS A total of 1898 patients were identified who had nonemergent cardiac surgery, between January 2007 and August 2013, without intra-aortic balloon pumps or reoperations, and with short (<24 hours) intensive care unit stays (age ≥75 years; n = 239). Patients age ≥75 years were propensity-score matched to those age <75 years to balance covariates, resulting in 222 patients per group. Analyses of the matched sample examined age as a continuous variable, scaled in 5-year increments. RESULTS After matching, covariates were balanced between older and younger patients. Older age significantly predicted postoperative (odds ratio = 1.39, P = .028), but not intraoperative (odds ratio = 0.96, P = .559), blood transfusion. Older age predicted longer length of stay (B = 0.21, P < .001), even after adjustment for blood product transfusion (B = 0.20, P < .001). As expected, older age was a significant predictor for poorer survival, even with multivariate adjustment (hazard ratio = 1.34, P = .042). CONCLUSIONS In patients with a routine postoperative course, older age was associated with more postoperative blood transfusion. Older age was also predictive of longer length of stay and poorer survival, even after accounting for clinical factors. Continued study into effects of transfusion, particularly in the elderly, should be directed toward hospital transfusion protocols to optimize perioperative care.

Amiodarone after surgical ablation for atrial fibrillation: Is it really necessary? A prospective randomized controlled trial.

OBJECTIVE Prophylactic antiarrhythmic drug (AAD) treatment is a well-established practice after catheter ablation for atrial fibrillation (AF), but it is controversial after surgical ablation. This prospective randomized controlled trial examined whether amiodarone after surgical ablation reduced atrial arrhythmia recurrence within the first 3 months after surgery. METHODS Ninety patients were randomized to receive (n = 45) or not receive (n = 45) amiodarone after surgical ablation. Rhythm status was ascertained via clinical follow-up and 72-hour continuous monitoring at 6 and 12 weeks, using Heart Rhythm Society guidelines. Primary outcome was defined as atrial arrhythmia recurrence, cardioversion, ablation, or crossover from no-amiodarone to amiodarone as a result of atrial arrhythmia during follow-up. An intention-to-treat approach was used. RESULTS The 2 study groups were similar in traditional predictors for failure, including left atrium size (5.0 vs 5.1 cm, P = .734), median AF duration (23 vs 20 months, P = .513), and long-standing persistent AF (44% vs 33%, P = .280). The primary outcome occurred in 52% of the no-amiodarone group (23 of 44) and 19% of the amiodarone group (8 of 43; P = .001). Cumulative freedom from primary outcome was greater in the amiodarone group (81.4% vs 47.7%, P < .001). Amiodarone was discontinued in 18 patients randomized to amiodarone for side effects, bradycardia, or noncompliance. CONCLUSIONS Prophylactic amiodarone reduced early atrial arrhythmia recurrence. These results are consistent with catheter AF ablation findings and should inform recommendations for prophylactic class I/III AAD after surgical AF ablation, regardless of discharge rhythm status. As previously recommended, monitoring for side effects and amiodarone discontinuation by 3 months, for patients in sinus rhythm, is warranted. CLINICAL TRIAL REGISTRATION NCT01416935.

The Effects of Frailty in Patients Undergoing Elective Cardiac Surgery.

The Society of Thoracic Surgeons (STS) recommends using gait speed as a marker of frailty to identify cardiac surgery patients at risk for adverse outcomes. However, a single marker of frailty may not provide consistently reliable risk information. We evaluated the impact of frailty and gait speed on patient outcomes after elective cardiac surgery.

Potential Impact of Modifiable Clinical Variables on Length of Stay After First-Time Cardiac Surgery

BACKGROUND Recent financial challenges highlight the importance of accurate prediction of length of hospital stay (LOS). We assessed reliability of The Society of Thoracic Surgeons (STS) risk prediction for extended and shorter LOS and examined whether modifiable clinical variables are associated with LOS in first-time cardiac surgery patients. METHODS Isolated aortic valve, mitral valve, and coronary artery bypass graft surgery patients since 2008 were included (n = 3,472). Multivariate regression was used to evaluate nonmodifiable and potentially modifiable (preoperative hematocrit, hemoglobin A1c, body mass index, current smoker, major perioperative morbidity, and blood product transfusion) predictors of LOS in days. RESULTS Mean age was 63.9 ± 11.2 years, 76% were males, and mean STS mortality risk was 1.9% ± 3.2%. Median (interquartile range) LOS was 4 (3 to 6) days. Predicted STS risk was 6.2% ± 7.1% for extended LOS (>14 days) and 48.3% ± 20.2% for short LOS (<6 days). Extended LOS was observed in 5.2% of patients (observed versus expected, 0.84; p = 0.019). Observed short LOS was better than predicted (67.8%; observed versus expected, 1.40; p < 0.001). Inclusion of modifiable variables in the LOS prediction model was significant (p < 0.001). Significant modifiable predictors were lower hematocrit, higher hemoglobin A1c, major morbidity, and transfusion. Longer predicted LOS from the model correlated with longer actual LOS (rs = 0.63; p < 0.001). Applying the prediction equation from the model to a hypothetical average patient, predicted LOS was 4.6 days. CONCLUSIONS The STS risk model was reliably predictive of short and extended LOS but did not allow prediction of exact LOS in days. Accounting for potentially modifiable clinical variables, such as low hematocrit and blood transfusion, especially in elective patients, should lead to shorter LOS, higher satisfaction, and reduced financial burden.

Minimally invasive mitral valve surgery without aortic cross-clamping and with femoral cannulation is not associated with increased risk of stroke compared with traditional mitral valve surgery: a propensity score-matched analysis †

OBJECTIVES Open-heart surgery with fibrillatory arrest has been reported to be associated with an increased risk of stroke. We examined whether minimally invasive mitral valve surgery with fibrillatory arrest conferred a higher risk of stroke/transient ischaemic attack (TIA) and other major complications compared with median sternotomy and cardioplegic arrest. METHODS Data were collected prospectively for 387 patients who had mitral valve surgery; 239 had a minimally invasive surgical approach and 148 had median sternotomy. All minimally invasive surgeries were performed by surgeons who were experienced in minimally invasive techniques. The effect of operative approach on risk of stroke/TIA and major morbidity was examined. After propensity score matching (PSM) was conducted between the two groups, 76 patients remained in each group. RESULTS Before matching, the incidence of stroke/TIA did not differ between patients who had minimally invasive surgery (0.5%, n = 1) and those who had median sternotomy (1.4%, n = 2; P = 0.56). Patients who had minimally invasive surgery had a lower incidence of other major morbidity (0.8%, n = 2) than patients who had median sternotomy (6.1%, n = 9; P = 0.004). After adjustment for age and Society of Thoracic Surgeons predicted risk, there was no effect of operative approach on the odds for stroke/TIA (odds ratio [OR] = 0.41, P = 0.49) or other major morbidity (OR = 0.40, P = 0.31). After PSM, patients were balanced on preoperative characteristics. No patient in either matched group experienced permanent stroke/TIA, and major morbidity did not differ between the two groups (minimally invasive, 1.3%, n = 1; median sternotomy, 1.3%, n = 1; P > 0.99). CONCLUSIONS A minimally invasive approach for mitral valve surgery on a fibrillating heart was not associated with a greater incidence of stroke/TIA than was median sternotomy. When performed by highly experienced surgeons, the minimally invasive approach with fibrillatory arrest did not increase the risk of perioperative stroke.

Operative risk and preoperative hematocrit in bypass graft surgery: Role of gender and blood transfusion.

BACKGROUND The association between lower preoperative hematocrit (Hct) and risk for morbidity/mortality after cardiac surgery is well established. We examined whether the impact of low preoperative Hct on outcome is modified by blood transfusion and operative risk in women and men undergoing nonemergent CABG surgery. METHODS Patients having nonemergent, first-time, isolated CABG were included (N=2757). Logistic regressions assessed effect of hematocrit on major perioperative morbidity/mortality separately by males (n=2232) and females (n=525). RESULTS Mean age was 63.2±10.1years, preoperative hematocrit was 38.9±4.8%, and STS risk score was 1.3±1.8%. Blood transfusion was more likely in female patients (26% vs. 12%, P<0.001). Multivariate analyses revealed that lower body mass index and lower preoperative hematocrit predicted transfusion in males and females, whereas older age (OR=1.03, P=0.017) also predicted transfusion in females. Major morbidity was also more likely in female patients (12% vs. 7%, P<0.001). In multivariate analyses, blood transfusion was the only predictive factor for major morbidity in females (OR=4.56, P<0.001). In males, higher body mass index (OR=1.07, P<0.001), lower hematocrit (OR=0.94, P=0.017), interaction of STS score with hematocrit (OR=1.02, P=0.045), and blood transfusion (OR=9.22, P<0.001) were significant predictors for major morbidity. CONCLUSIONS This study showed females were more likely to have blood transfusion and major morbidities after nonemergent CABG. Traditional factors that have been found to predict outcomes, such as hematocrit and STS risk, were related only to major morbidity in male patients. However, blood transfusion negatively impacted major outcome after nonemergent CABG surgery across all STS risk levels in both genders.

The Effect of Initiation of a Transcatheter Aortic Valve Replacement Program in the Treatment of Severe Aortic Stenosis

We assessed the effect of a transcatheter aortic valve replacement (TAVR) program and Heart Team concept on our approach to severe isolated symptomatic aortic stenosis (AS) with regard to surgical practice, patient selection, perioperative outcomes, 1-year survival, and AVR volume. TAVR program began in August 2011. Patients having isolated surgical AVR between January 2008 and August 2011, when the program began (n = 282, 42 months), were compared with those after the program began until February 2015 (n = 344, surgical AVR and n = 126, TAVR, 42 months). Isolated surgical AVR accounted for 21% of all valve procedures (isolated and concomitant) before and after the TAVR program. However, the volume of all isolated AVR (surgical and transcatheter) increased to 27% of all valve procedures (isolated and concomitant) after the TAVR program implementation. Mean Society Of Thoracic Surgeons (STS)-predicted mortality risk was similar among patients who had surgical AVR pre-TAVR and post-TAVR implementation (2.3% vs 2.1%, P = 0.227), but addition of patients who had TAVR (STS risk = 7.1%) increased STS-predicted risk for all isolated AVR (surgical and transcatheter) procedures (2.3% vs 3.4%, P < 0.001). A similar trend was found for age, including a slight decrease in octogenarians for surgical AVR post-TAVR (18% vs 13%, P = 0.084). Operative mortality for isolated surgical AVR was similar in pre-TAVR and post-TAVR (2.1% vs 1.8%, P = 0.798), as were observed/expected (O/E) ratios (0.91 vs 0.82). For all isolated AVR, O/E ratio was 0.91 pre-TAVR and 0.82 post-TAVR (n = 470), including O/E = 0.79 for patients who had TAVR. No changes were found in proportion of isolated surgical AVR cases or patient risk and outcomes after introduction of TAVR program and Heart Team. However, volume of patients with severe AS treated increased significantly post-TAVR. Our results reflect growing awareness of TAVR availability and accompanying increases in patients referred to our Heart Team for AS treatment.

Impact of Atrial Fibrillation Duration on the Success of First-Time Concomitant Cox Maze Procedures

BACKGROUND Atrial fibrillation (AF) duration is one of the most consistent predictors of Cox maze (CM) procedure failure. We examined the impact of AF duration on CM success in patients having first-time concomitant surgery. METHODS First-time concomitant CM was performed in 505 patients. Freedom from atrial arrhythmia (AA) and class I/III antiarrhythmic drug (AAD) data were collected prospectively. Patients with longer AF duration (≥ 5 years; n = 113) were compared with shorter duration (<5 years; n = 392) in primary analyses. The AF duration was examined as a continuous variable in regression analyses. RESULTS Patients with longer AF duration were older (68.4 vs 65.1 years, p = 0.002) and in long-standing persistent AF (80% vs 36%, p < 0.001). Freedom from AA and AA off AAD was lower in longer duration patients at 1 year (80% vs 94%, p < 0.001; 74 vs 87%, p = 0.005) and 2 years (69 vs 90%, p < 0.001; 61 vs 81%, p = 0.001). Freedom from stroke or transient ischemic attack (TIA) was similar (96.1% vs 95.4%, p = 0.65). Adjusting for clinical and AF-associated factors, each 1-year increase in AF duration had 13% greater odds for failure at 1 year (odds ratio [OR], 1.13, p = 0.004) and 20% greater odds at 2 years (OR, 1.20, p < 0.001). Cryothermia as sole energy source attenuated the negative impact of AF duration on 1-year success. CONCLUSIONS Longer AF duration significantly impacted CM success and may result from extensive tissue remodeling. Patients with longer AF duration can expect reasonable success rates, especially when on AAD, and low stroke rates during follow-up. Cryoablation may reduce AF duration impact on success compared with combined bipolar radiofrequency and cryothermia.