© 2014 Wiley Periodicals, Inc.
572
TRANSPLANTATION AND MECHANICAL SUPPORT ORIGINAL ARTICLE _____________________________________________________________
The Incidence, Risk, and Consequences of Atrial Arrhythmias in Patients with Continuous-Flow Left Ventricular Assist Devices Meredith A. Brisco, M.D., M.S.C.E.,* Kartik S. Sundareswaran, Ph.D.,y Carmelo A. Milano, M.D.,z David Feldman, M.D.,§ Jeffrey M. Testani, M.D., M.T.R.,{ Gregory A. Ewald, M.D.,jj Mark S. Slaughter, M.D.,# David J. Farrar, Ph.D.,y Lee R. Goldberg, M.D., M.P.H.,? for the HeartMate II Clinical Investigators *Department of Medicine, Cardiovascular Division, Medical University of South Carolina, Charleston, South Carolina; yThoratec Corporation, Pleasanton, California; zDuke University Medical Center, Durham, North Carolina; §Abbott Northwestern Hospital, Morehouse School of Medicine and the Georgia Institute of Technology, Minneapolis, Minnesota; {Yale University School of Medicine, New Haven, Connecticut; jjBarnes-Jewish Hospital, St. Louis, Missouri; #University of Louisville, Louisville, Kentucky; and ?Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania ABSTRACT Background: Although atrial arrhythmias (AAs) are common in heart failure, the incidence of AAs subsequent to the placement of left ventricular assist devices (LVADs) has not been elucidated. Methods: Patients receiving a HeartMate II LVAD in the bridge to transplant (n = 490) and destination therapy (n = 634) trials were included (n = 1125). AAs requiring treatment were recorded, regardless of symptoms. Using Cox models with and without a 60-day blanking period, risk factors for early and late AAs were determined. Results: In total, there were 271 AAs in 231 patients (21%), most of which occurred within the first 60 days. Patients with and without AAs had similar survival (p = 0.16). Serum creatinine (hazard ratio [HR] = 1.49 per unit increase, 1.18 to 1.88; p < 0.001) and ejection fraction (HR = 0.98 per 1% increase, 0.95 to 0.999; p = 0.04) were associated with AAs in a multivariable model. Although quality of life (QoL) and functional status improved in all patients, those with AAs had worse unadjusted QoL (p < 0.001) and a decreased rate of improvement in six-minute walk distance over six to 24 months postimplant (p = 0.016). Conclusions: Approximately one-fifth of LVAD patients have AAs, most commonly within the first 60 days of support. Preoperative creatinine is a strong risk factor for early and late AAs. Although AAs do not impact survival, they are associated with decreased functional status and QoL improvements during LVAD support. doi:
10.1111/jocs.12336 (J Card Surg 2014;29:572–580)
Presented: American Heart Association 2011, Orlando, Florida. Conflict of interest: Drs. Sundareswaren and Farrar are employees of Thoratec Corporation. Drs. Milano and Slaughter have received research support from Thoratec Corporation. Drs. Ewald and Goldberg have received consulting fees from Thoratec Corporation. ClinicalTrials.gov No: NCT00121485 and NCT00121472. † A complete list of study investigators has been previously published (N Engl J Med 2009;361:241–2251).
Grant sponsor: Thoratec Corporation (Pleasanton, CA) Address for correspondence: Meredith A. Brisco, M.D., M.S.C.E., Assistant Professor of Medicine, Medical University of South Carolina, 25 Courtenay Drive, ART 7061, MSC 592, Charleston, SC 29425. Fax: þ1-843-876-4809; e-mail: [email protected]
Atrial arrhythmias (AAs) are common in patients with heart failure (HF) and are associated with increased risk of HF exacerbation, embolic events, hospitalization, and mortality.1–4 As severity of HF increases, the prevalence of AAs also increases, approaching 50% in those with New York Heart Association class IV symptoms.5 The increased atrial stretch and slowed atrial conduction secondary to a failing myocardium and fluid overload might account for this increased prevalence.6,7 Additionally, interdependence exists between AAs and HF such that the arrhythmias themselves can worsen HF symptoms, decreasing functional capacity and quality of life (QoL).8,9 While it stands to reason that
J CARD SURG 2014;29:572–580
treatment of HF may decrease AA burden through several mechanisms, the effect of ventricular unloading on AAs is not well known. Left ventricular assist devices (LVADs) are an accepted treatment for advanced HF. With the advent of newer continuous-flow devices, LVADs have been increasingly employed as both a bridge to transplant (BTT) and destination therapy (DT).10,11 Ventricular unloading that occurs with LVADs leads to a reduction in left ventricular size, reverse remodeling, and decreased sympathetic nervous system activation, with the associated clinical benefits of improved survival, functional status and QoL.12–14 Furthermore, shortening of the QTc and QRS intervals with LVAD support indicate the presence of electrophysiologic remodeling.15 Despite the theoretical belief that LVADs should decrease AA burden, data are limited regarding the incidence of AAs in LVAD patients. The HeartMate II (Thoratec Corporation, Pleasanton, CA, USA) BTT and DT trials were multicenter clinical trials of the efficacy and safety of continuous-flow LVADs. The primary aim of this study was to determine the incidence and risk factors for AAs in patients post the HeartMate II LVAD. Our secondary objective was to examine the influence of AAs on mortality, functional status, and QoL. MATERIALS AND METHODS This is a post-hoc analysis of patients enrolled in the multicenter HeartMate II BTT and DT trials. Patients who received the HeartMate XVE (Thoratec Corporation) in the randomized trial or received a HMII as an exchange for a HeartMate XVE were excluded. The clinical trial was an investigator-directed trial funded and coordinated by the Thoratec Corporation. A data and safety monitoring board met regularly to review study compliance, adverse events, and outcomes. The study was conducted in compliance with U.S. FDA regulations for Good Clinical Practice. The FDA and the institutional review boards at each participating center approved the protocol. Study subjects, baseline assessment, and followup Inclusion and exclusion criteria for the BTT and DT trials have been described previously.11,12 Patients with advanced HF refractory to optimal medical management were eligible. All patients provided written informed consent. Data analyzed included patient characteristics, laboratory data, and hemodynamic measurements. Postoperative antithrombotic therapy with warfarin was initiated with an initial targeted INR between 2.0 and 3.0 (in practice 1.5 to 2.5); however, physicians were encouraged to determine an anticoagulation strategy for each patient based on the underlying risk of thromboembolic complications, which included atrial fibrillation. Ultimately, postoperative medical care (including antiarrhythmic and subsequent anticoagulant therapy) was managed according to each site’s usual practice. The clinical management
BRISCO, ET AL. ATRIAL ARRHYTHMIAS IN CF-LVADs
573
protocol has been published previously.16 A clinical events committee adjudicated all adverse events, which have been previously defined. Outcomes Patients were followed up until the end of the study period of 24 months post-LVAD implantation. The primary outcome was onset of AAs. The investigators were told to classify four different types of arrhythmia events: (1) cardiac arrest, (2) ventricular arrhythmias, (3) supraventricular arrhythmias, and (4) AAs. AAs were defined as any symptomatic or asymptomatic AA that required intervention; however, intervention ranged from minor electrolyte repletion to more invasive approaches such as cardioversion or arrhythmia ablation. Although continuous telemetry was employed during hospitalizations, patients were not routinely followed with Holter monitors, or defibrillator or cardiac resynchronization therapy device interrogations for the express purpose of arrhythmia surveillance. Early AAs were defined as those that occurred within 60 days of LVAD implantation, and late AAs were defined as arrhythmias that occurred after 60 days. Patients with AAs (N ¼ 231) were compared to patients without any arrhythmia events (N ¼ 524). Survival was compared for patients with and without early and late AAs. Causes of death were determined at autopsy or by examination of medical records. Other outcomes included functional capacity and QoL, which were assessed at baseline, before LVAD implantation, and at 1, 3, 6, 12, 18, and 24 months. Functional assessment included NYHA functional class and sixminute walk distance (6MWD). Heart failure-related QoL was determined using the Minnesota Living with Heart Failure (MLWHF) and Kansas City Cardiomyopathy (KCCQ) questionnaires. Right ventricular (RV) failure was defined as requiring either RVAD implantation or inotropic therapy >14 days after implant with symptoms of congestion; echocardiography was not routinely performed or required for this diagnosis. Statistical analysis Values reported are mean SD and percentile. Independent Student’s t-test and the Mann-Whitney U-test were used to compare continuous parameters. Pearson’s x2 was used to evaluate categorical variables. Cox proportional hazards modeling was used to evaluate associations with time to development of AAs. Candidate covariates for the multivariable Cox models, adjusting for baseline characteristics, were selected based on what was associated with AAs at p 0.2 in the univariate analysis. Covariates that had a p > 0.2 but theoretical basis for potential confounding were inserted into the model. Forward stepwise Cox proportional hazards regression was used to build the multivariable model. Variables were retained if the pvalue was 14 days after implant with symptoms of congestion, occurred more frequently in the AA group (Table 4; p < 0.0001). When the incidence of RV failure was compared only among patients whose RV failure occurred prior to their AA (n ¼ 34/81), there was no statistically significant difference between the groups (Fig. 4).
DISCUSSION
Figure 2. Differences in Quality of Life and Functional Status among patients with and without atrial arrhythmias as measured by the Minnesota Living with Heart Failure (MLWHF) total scores (Panel A), the Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary scores (Panel B) and six-minute walk distance (Panel C).
consistently lower than in patients without AAs (p < 0.001). Significant improvements in functional status were noted in all patients, but patients without AAs attained significantly greater 6MWD (p ¼ 0.015, Fig. 2C). Notably, patients with AAs experienced delayed improvement in functional status exemplified by only mild differences between baseline and one-month 6MWDs. At 24 months, both groups attained mean 6MWD greater than 340 m (Fig. 2C).
This study of AAs in patients with LVADs demonstrates that (1) AAs occur in approximately one-fifth of patients without an associated mortality risk, (2) creatinine and EF are strong risk factors for AA development, (3) AAs negatively impact the magnitude of QoL improvement and functional status, and (4) postimplant RV failure and AAs may be intimately related. In LVAD patients, AAs are more common within the first 60 days secondary to the hemodynamic perturbations and inflammatory responses associated with cardiac surgery, in addition to direct tissue stimulation from right atrial cannulation during bypass.17,18 The reason for the decline in events after 60 days is less apparent. One possibility is that rehabilitation and surgical recovery, as well as electrical remodeling, lead to fewer stimuli for AAs.12 Still, an AA prevalence of only 6%, much lower than the rates reported in patients with NYHA class II HF, suggests that effective unloading and potentially cardiac (atrial) remodeling as well as decreased adrenergic stimulation may play a role.5 Left atrial size is an important factor in AAs; increased LA size is associated with increased AF in patients with and without structural heart disease.4 Additionally, smaller LA diameter predicts acute termination of AF after AF ablation and freedom from AF recurrence.19 As electrical and structural atrial remodeling can occur independently, without LA measurements or voltage mapping, the exact mechanism is unknown. In light of recent evidence illustrating a significantly decreased long-term survival in patients with atrial fibrillation post–coronary artery bypass grafting, it is surprising that neither early nor late AAs appeared to have a mortality impact.20 One potential explanation is that AAs may affect survival indirectly in LVAD patients, that is, via increased RV dysfunction or bleeding. Currently the effects of AAs on a mechanically
J CARD SURG 2014;29:572–580
BRISCO, ET AL. ATRIAL ARRHYTHMIAS IN CF-LVADs
577
TABLE 4 Adverse Events in Patients with and without Atrial Arrhythmias
Adverse Event Bleeding requiring PRBC Bleeding requiring exploration Gastrointestinal bleeding Infection: local non-device Infection: sepsis Infection: any device-related Infection: driveline infection Renal failure Right ventricular failure RVAD Ischemic stroke Hemorrhagic stroke Other neurologic events Hemolysis Pump thrombosis Pump replacements
No Atrial Arrhythmias
Atrial Arrhythmias
(N = 524; 728.5 Patient Years)
(N = 231; 324.1 Patient Years)
Patients (%) 334 101 112 200 107 122 109 48 83 26 46 29 65 21 15 31
(63.7) (19.3) (21.4) (38.2) (20.4) (23.3) (20.8) (9.2) (15.8) (5.0) (8.8) (5.5) (12.4) (4.0) (2.9) (5.9)
Events (Event Rate) 873 114 252 365 143 232 190 50 86 26 47 30 76 29 16 33
(1.20) (0.16) (0.35) (0.50) (0.20) (0.32) (0.26) (0.07) (0.12) (0.04) (0.06) (0.04) (0.10) (0.04) (0.02) (0.04)
Patients (%) 169 64 55 123 77 63 58 44 81 18 18 17 36 8 5 13
(73.2) (27.7) (23.8) (53.3) (33.3) (27.3) (25.1) (19.1) (35.1) (7.8) (7.8) (7.4) (15.6) (3.5) (2.2) (5.6)
Events (Event Rate) 490 74 102 239 147 111 91 45 96 18 21 18 42 9 6 13
(1.51) (0.23) (0.31) (0.74) (0.45) (0.34) (0.28) (0.14) (0.30) (0.06) (0.06) (0.06) (0.13) (0.03) (0.02) (0.04)
IRR [95% CI] 1.26 1.46 0.91 1.47 2.31 1.08 1.08 2.02 2.51 1.56 1.00 1.35 1.24 0.70 0.84 0.89
[1.06–1.50] [1.06–2.01] [0.70–1.19] [1.19–1.81] [1.77–3.01] [0.83–1.40] [0.81–1.43] [1.32–3.09] [1.82–3.45] [0.84–2.88] [0.59–1.71] [0.74–2.45] [0.83–1.85] [0.33–1.49] [0.22–3.20] [0.46–0.72]
P-Value 0.008 0.020 0.489
572
TRANSPLANTATION AND MECHANICAL SUPPORT ORIGINAL ARTICLE _____________________________________________________________
The Incidence, Risk, and Consequences of Atrial Arrhythmias in Patients with Continuous-Flow Left Ventricular Assist Devices Meredith A. Brisco, M.D., M.S.C.E.,* Kartik S. Sundareswaran, Ph.D.,y Carmelo A. Milano, M.D.,z David Feldman, M.D.,§ Jeffrey M. Testani, M.D., M.T.R.,{ Gregory A. Ewald, M.D.,jj Mark S. Slaughter, M.D.,# David J. Farrar, Ph.D.,y Lee R. Goldberg, M.D., M.P.H.,? for the HeartMate II Clinical Investigators *Department of Medicine, Cardiovascular Division, Medical University of South Carolina, Charleston, South Carolina; yThoratec Corporation, Pleasanton, California; zDuke University Medical Center, Durham, North Carolina; §Abbott Northwestern Hospital, Morehouse School of Medicine and the Georgia Institute of Technology, Minneapolis, Minnesota; {Yale University School of Medicine, New Haven, Connecticut; jjBarnes-Jewish Hospital, St. Louis, Missouri; #University of Louisville, Louisville, Kentucky; and ?Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania ABSTRACT Background: Although atrial arrhythmias (AAs) are common in heart failure, the incidence of AAs subsequent to the placement of left ventricular assist devices (LVADs) has not been elucidated. Methods: Patients receiving a HeartMate II LVAD in the bridge to transplant (n = 490) and destination therapy (n = 634) trials were included (n = 1125). AAs requiring treatment were recorded, regardless of symptoms. Using Cox models with and without a 60-day blanking period, risk factors for early and late AAs were determined. Results: In total, there were 271 AAs in 231 patients (21%), most of which occurred within the first 60 days. Patients with and without AAs had similar survival (p = 0.16). Serum creatinine (hazard ratio [HR] = 1.49 per unit increase, 1.18 to 1.88; p < 0.001) and ejection fraction (HR = 0.98 per 1% increase, 0.95 to 0.999; p = 0.04) were associated with AAs in a multivariable model. Although quality of life (QoL) and functional status improved in all patients, those with AAs had worse unadjusted QoL (p < 0.001) and a decreased rate of improvement in six-minute walk distance over six to 24 months postimplant (p = 0.016). Conclusions: Approximately one-fifth of LVAD patients have AAs, most commonly within the first 60 days of support. Preoperative creatinine is a strong risk factor for early and late AAs. Although AAs do not impact survival, they are associated with decreased functional status and QoL improvements during LVAD support. doi:
10.1111/jocs.12336 (J Card Surg 2014;29:572–580)
Presented: American Heart Association 2011, Orlando, Florida. Conflict of interest: Drs. Sundareswaren and Farrar are employees of Thoratec Corporation. Drs. Milano and Slaughter have received research support from Thoratec Corporation. Drs. Ewald and Goldberg have received consulting fees from Thoratec Corporation. ClinicalTrials.gov No: NCT00121485 and NCT00121472. † A complete list of study investigators has been previously published (N Engl J Med 2009;361:241–2251).
Grant sponsor: Thoratec Corporation (Pleasanton, CA) Address for correspondence: Meredith A. Brisco, M.D., M.S.C.E., Assistant Professor of Medicine, Medical University of South Carolina, 25 Courtenay Drive, ART 7061, MSC 592, Charleston, SC 29425. Fax: þ1-843-876-4809; e-mail: [email protected]
Atrial arrhythmias (AAs) are common in patients with heart failure (HF) and are associated with increased risk of HF exacerbation, embolic events, hospitalization, and mortality.1–4 As severity of HF increases, the prevalence of AAs also increases, approaching 50% in those with New York Heart Association class IV symptoms.5 The increased atrial stretch and slowed atrial conduction secondary to a failing myocardium and fluid overload might account for this increased prevalence.6,7 Additionally, interdependence exists between AAs and HF such that the arrhythmias themselves can worsen HF symptoms, decreasing functional capacity and quality of life (QoL).8,9 While it stands to reason that
J CARD SURG 2014;29:572–580
treatment of HF may decrease AA burden through several mechanisms, the effect of ventricular unloading on AAs is not well known. Left ventricular assist devices (LVADs) are an accepted treatment for advanced HF. With the advent of newer continuous-flow devices, LVADs have been increasingly employed as both a bridge to transplant (BTT) and destination therapy (DT).10,11 Ventricular unloading that occurs with LVADs leads to a reduction in left ventricular size, reverse remodeling, and decreased sympathetic nervous system activation, with the associated clinical benefits of improved survival, functional status and QoL.12–14 Furthermore, shortening of the QTc and QRS intervals with LVAD support indicate the presence of electrophysiologic remodeling.15 Despite the theoretical belief that LVADs should decrease AA burden, data are limited regarding the incidence of AAs in LVAD patients. The HeartMate II (Thoratec Corporation, Pleasanton, CA, USA) BTT and DT trials were multicenter clinical trials of the efficacy and safety of continuous-flow LVADs. The primary aim of this study was to determine the incidence and risk factors for AAs in patients post the HeartMate II LVAD. Our secondary objective was to examine the influence of AAs on mortality, functional status, and QoL. MATERIALS AND METHODS This is a post-hoc analysis of patients enrolled in the multicenter HeartMate II BTT and DT trials. Patients who received the HeartMate XVE (Thoratec Corporation) in the randomized trial or received a HMII as an exchange for a HeartMate XVE were excluded. The clinical trial was an investigator-directed trial funded and coordinated by the Thoratec Corporation. A data and safety monitoring board met regularly to review study compliance, adverse events, and outcomes. The study was conducted in compliance with U.S. FDA regulations for Good Clinical Practice. The FDA and the institutional review boards at each participating center approved the protocol. Study subjects, baseline assessment, and followup Inclusion and exclusion criteria for the BTT and DT trials have been described previously.11,12 Patients with advanced HF refractory to optimal medical management were eligible. All patients provided written informed consent. Data analyzed included patient characteristics, laboratory data, and hemodynamic measurements. Postoperative antithrombotic therapy with warfarin was initiated with an initial targeted INR between 2.0 and 3.0 (in practice 1.5 to 2.5); however, physicians were encouraged to determine an anticoagulation strategy for each patient based on the underlying risk of thromboembolic complications, which included atrial fibrillation. Ultimately, postoperative medical care (including antiarrhythmic and subsequent anticoagulant therapy) was managed according to each site’s usual practice. The clinical management
BRISCO, ET AL. ATRIAL ARRHYTHMIAS IN CF-LVADs
573
protocol has been published previously.16 A clinical events committee adjudicated all adverse events, which have been previously defined. Outcomes Patients were followed up until the end of the study period of 24 months post-LVAD implantation. The primary outcome was onset of AAs. The investigators were told to classify four different types of arrhythmia events: (1) cardiac arrest, (2) ventricular arrhythmias, (3) supraventricular arrhythmias, and (4) AAs. AAs were defined as any symptomatic or asymptomatic AA that required intervention; however, intervention ranged from minor electrolyte repletion to more invasive approaches such as cardioversion or arrhythmia ablation. Although continuous telemetry was employed during hospitalizations, patients were not routinely followed with Holter monitors, or defibrillator or cardiac resynchronization therapy device interrogations for the express purpose of arrhythmia surveillance. Early AAs were defined as those that occurred within 60 days of LVAD implantation, and late AAs were defined as arrhythmias that occurred after 60 days. Patients with AAs (N ¼ 231) were compared to patients without any arrhythmia events (N ¼ 524). Survival was compared for patients with and without early and late AAs. Causes of death were determined at autopsy or by examination of medical records. Other outcomes included functional capacity and QoL, which were assessed at baseline, before LVAD implantation, and at 1, 3, 6, 12, 18, and 24 months. Functional assessment included NYHA functional class and sixminute walk distance (6MWD). Heart failure-related QoL was determined using the Minnesota Living with Heart Failure (MLWHF) and Kansas City Cardiomyopathy (KCCQ) questionnaires. Right ventricular (RV) failure was defined as requiring either RVAD implantation or inotropic therapy >14 days after implant with symptoms of congestion; echocardiography was not routinely performed or required for this diagnosis. Statistical analysis Values reported are mean SD and percentile. Independent Student’s t-test and the Mann-Whitney U-test were used to compare continuous parameters. Pearson’s x2 was used to evaluate categorical variables. Cox proportional hazards modeling was used to evaluate associations with time to development of AAs. Candidate covariates for the multivariable Cox models, adjusting for baseline characteristics, were selected based on what was associated with AAs at p 0.2 in the univariate analysis. Covariates that had a p > 0.2 but theoretical basis for potential confounding were inserted into the model. Forward stepwise Cox proportional hazards regression was used to build the multivariable model. Variables were retained if the pvalue was 14 days after implant with symptoms of congestion, occurred more frequently in the AA group (Table 4; p < 0.0001). When the incidence of RV failure was compared only among patients whose RV failure occurred prior to their AA (n ¼ 34/81), there was no statistically significant difference between the groups (Fig. 4).
DISCUSSION
Figure 2. Differences in Quality of Life and Functional Status among patients with and without atrial arrhythmias as measured by the Minnesota Living with Heart Failure (MLWHF) total scores (Panel A), the Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary scores (Panel B) and six-minute walk distance (Panel C).
consistently lower than in patients without AAs (p < 0.001). Significant improvements in functional status were noted in all patients, but patients without AAs attained significantly greater 6MWD (p ¼ 0.015, Fig. 2C). Notably, patients with AAs experienced delayed improvement in functional status exemplified by only mild differences between baseline and one-month 6MWDs. At 24 months, both groups attained mean 6MWD greater than 340 m (Fig. 2C).
This study of AAs in patients with LVADs demonstrates that (1) AAs occur in approximately one-fifth of patients without an associated mortality risk, (2) creatinine and EF are strong risk factors for AA development, (3) AAs negatively impact the magnitude of QoL improvement and functional status, and (4) postimplant RV failure and AAs may be intimately related. In LVAD patients, AAs are more common within the first 60 days secondary to the hemodynamic perturbations and inflammatory responses associated with cardiac surgery, in addition to direct tissue stimulation from right atrial cannulation during bypass.17,18 The reason for the decline in events after 60 days is less apparent. One possibility is that rehabilitation and surgical recovery, as well as electrical remodeling, lead to fewer stimuli for AAs.12 Still, an AA prevalence of only 6%, much lower than the rates reported in patients with NYHA class II HF, suggests that effective unloading and potentially cardiac (atrial) remodeling as well as decreased adrenergic stimulation may play a role.5 Left atrial size is an important factor in AAs; increased LA size is associated with increased AF in patients with and without structural heart disease.4 Additionally, smaller LA diameter predicts acute termination of AF after AF ablation and freedom from AF recurrence.19 As electrical and structural atrial remodeling can occur independently, without LA measurements or voltage mapping, the exact mechanism is unknown. In light of recent evidence illustrating a significantly decreased long-term survival in patients with atrial fibrillation post–coronary artery bypass grafting, it is surprising that neither early nor late AAs appeared to have a mortality impact.20 One potential explanation is that AAs may affect survival indirectly in LVAD patients, that is, via increased RV dysfunction or bleeding. Currently the effects of AAs on a mechanically
J CARD SURG 2014;29:572–580
BRISCO, ET AL. ATRIAL ARRHYTHMIAS IN CF-LVADs
577
TABLE 4 Adverse Events in Patients with and without Atrial Arrhythmias
Adverse Event Bleeding requiring PRBC Bleeding requiring exploration Gastrointestinal bleeding Infection: local non-device Infection: sepsis Infection: any device-related Infection: driveline infection Renal failure Right ventricular failure RVAD Ischemic stroke Hemorrhagic stroke Other neurologic events Hemolysis Pump thrombosis Pump replacements
No Atrial Arrhythmias
Atrial Arrhythmias
(N = 524; 728.5 Patient Years)
(N = 231; 324.1 Patient Years)
Patients (%) 334 101 112 200 107 122 109 48 83 26 46 29 65 21 15 31
(63.7) (19.3) (21.4) (38.2) (20.4) (23.3) (20.8) (9.2) (15.8) (5.0) (8.8) (5.5) (12.4) (4.0) (2.9) (5.9)
Events (Event Rate) 873 114 252 365 143 232 190 50 86 26 47 30 76 29 16 33
(1.20) (0.16) (0.35) (0.50) (0.20) (0.32) (0.26) (0.07) (0.12) (0.04) (0.06) (0.04) (0.10) (0.04) (0.02) (0.04)
Patients (%) 169 64 55 123 77 63 58 44 81 18 18 17 36 8 5 13
(73.2) (27.7) (23.8) (53.3) (33.3) (27.3) (25.1) (19.1) (35.1) (7.8) (7.8) (7.4) (15.6) (3.5) (2.2) (5.6)
Events (Event Rate) 490 74 102 239 147 111 91 45 96 18 21 18 42 9 6 13
(1.51) (0.23) (0.31) (0.74) (0.45) (0.34) (0.28) (0.14) (0.30) (0.06) (0.06) (0.06) (0.13) (0.03) (0.02) (0.04)
IRR [95% CI] 1.26 1.46 0.91 1.47 2.31 1.08 1.08 2.02 2.51 1.56 1.00 1.35 1.24 0.70 0.84 0.89
[1.06–1.50] [1.06–2.01] [0.70–1.19] [1.19–1.81] [1.77–3.01] [0.83–1.40] [0.81–1.43] [1.32–3.09] [1.82–3.45] [0.84–2.88] [0.59–1.71] [0.74–2.45] [0.83–1.85] [0.33–1.49] [0.22–3.20] [0.46–0.72]
P-Value 0.008 0.020 0.489
