Implications of Frailty among Men with Implantable Cardioverter Defibrillators.

OBJECTIVES: Frailty is associated with adverse outcomes, but little is known of the impact of frailty on patients with implantable cardioverter defibrillators (ICDs). This study sought to determine the prevalence of frailty, based on quantitative assessment, and assessed its potential impact on outcomes among community-dwelling men with ICDs. METHODS: A total of 124 ICD-treated men presenting for a routine device clinic appointment between May and October 2016 underwent frailty assessment consisting of three components: shrinking (weight loss ≥5% during the past year), weakness (inability to rise from a chair without using their arms), and self-reported poor energy level. Patients who had no components were considered robust, those with 1 component were intermediate stage, and those with ≥2 components were deemed frail. RESULTS: Mean age was 70.4 (±9.7) years. Of the 124 men, 31 (25%) were considered to be frail, 65 (52%) were intermediate, and 28 (23%) were robust. Frail men were older and were more likely to have symptomatic heart failure, chronic kidney disease, and hypertension (P < 0.05 for all) compared with nonfrail men. During a follow-up of 16 months, frail men were significantly more likely to die compared with nonfrail men (29% vs 5.4%, P < 0.0003). The incidence of appropriate ICD shocks (16.1% vs 6.5%) or hospitalizations (38.7% vs 23.7%) tended to be higher among frail versus nonfrail patients, but neither reached statistical significance (P = 0.10). CONCLUSIONS: Almost one-fourth of men with ICD are frail. Almost one-third of frail ICD patients died within 16 months. It may be useful to assess frailty in patients with ICD.

Use of Computed Tomography to Distinguish Thrombus from Pannus on a Bioprosthetic Aortic Valve.

Bioprosthetic valve thrombosis was previously considered to be a relatively rare complication of surgical or transcatheter bioprosthetic valve replacement. Although echocardiograms can reliably show the characteristic findings of prosthetic valve stenosis, differentiating between thrombus formation and pannus overgrowth as the underlying cause of prosthetic valve dysfunction can be challenging. We present the case of a 75-year-old man who underwent transthoracic Doppler echocardiography in the presence of an elevated valvular gradient 2 years after his aortic valve had been surgically replaced with a bioprosthesis. The echocardiographic findings suggested prosthetic valve stenosis. Cardiac computed tomography, performed to distinguish between thrombus formation and pannus overgrowth, revealed hypoattenuated leaflet thickening and reduced leaflet mobility, which suggested thrombus. After the patient took oral anticoagulants for 3 months, images showed complete resolution of the previous abnormalities, thus confirming the diagnosis of bioprosthetic valve thrombosis. We found cardiac computed tomography valuable when evaluating our patient who had an elevated prosthetic valve gradient.

Association of cardiac implantable electronic devices with survival in bifascicular block and prolonged PR interval on electrocardiogram.

PURPOSE: Bifascicular block and prolonged PR interval on the electrocardiogram (ECG) have been associated with complete heart block and sudden cardiac death. We sought to determine if cardiac implantable electronic devices (CIED) improve survival in these patients. METHODS: We assessed survival in relation to CIED status among 636 consecutive patients with bifascicular block and prolonged PR interval on the ECG. In survival analyses, CIED was considered as a time-varying covariate. RESULTS: Average age was 76 ± 9 years, and 99% of the patients were men. A total of 167 (26%) underwent CIED (127 pacemaker only) implantation at baseline (n = 23) or during follow-up (n = 144). During 5.4 ± 3.8 years of follow-up, 83 (13%) patients developed complete or high-degree atrioventricular block and 375 (59%) died. Patients with a CIED had a longer survival compared to those without a CIED in the traditional, static analysis (log-rank p < 0.0001) but not when CIED was considered as a time-varying covariate (log-rank p = 0.76). In the multivariable model, patients with a CIED had a 34% lower risk of death (hazard ratio 0.66, 95% confidence interval 0.52-0.83; p = 0.001) than those without CIED in the traditional analysis but not in the time-varying covariate analysis (hazard ratio 1.05, 95% confidence interval 0.79-1.38; p = 0.76). Results did not change in the subgroup with a pacemaker only. CONCLUSIONS: Bifascicular block and prolonged PR interval on ECG are associated with a high incidence of complete atrioventricular block and mortality. However, CIED implantation does not have a significant influence on survival when time-varying nature of CIED implantation is considered.

Effect of coronary artery bypass graft surgery on left ventricular systolic function.

BACKGROUND: Changes in left ventricular (LV) systolic function in response to coronary artery bypass grafting (CABG) have not been fully assessed. METHODS: Between January 2001 and December 2014, 2,838 consecutive patients underwent isolated CABG at the Minneapolis Veterans Affairs Health Care System. Of these, 375 had echocardiographic assessment of LV function before (within 6 months) and after (3 to 24 months) CABG and were included in this analysis. RESULTS: While the mean LV ejection fraction (LVEF) did not change following CABG [(49±13)% vs. (49±12)%, P=0.51], LVEF decreased in the subgroup with normal (≥50%) pre-operative LVEF [from (59±5)% to (56±9)%, P<0.001] and improved in those with decreased (<50%) pre-operative LVEF [from (36±9)% to (41±12)%, P<0.001]. There was a significant reduction in LV internal diameter during end-diastole (LVIDd) (5.4±0.8 vs. 5.3±0.9, P=0.002) and an increase in left atrial diameter (LAD) (4.4±0.7 vs. 4.6±0.7, P<0.001). There were no perioperative changes in LV internal diameter during end-systole, LV mass, posterior wall thickness, or septal wall thickness. LVEF improved by >5% in 24% of the study population, did not change (+/- 5%) in 55%, and worsened by >5% in 21%. Patients with improved EF were less often diabetic and had lower pre-operative LVEF, and greater LV dimensions at baseline. CONCLUSIONS: After CABG, there was a decrease in LVIDd and an increase in LAD. Also, a decrease in LV systolic function with CABG was observed in patients with normal pre-operative LVEF and an improvement in LV systolic function was observed in patients with decreased pre-operative LVEF.

Effect of Sleep-Disordered Breathing on Appropriate Implantable Cardioverter-Defibrillator Therapy in Patients With Heart Failure: A Systematic Review and Meta-Analysis.

BACKGROUND: Patients with heart failure and reduced ejection fraction are at increased risk of malignant ventricular arrhythmias. Implantable cardioverter-defibrillator (ICD) is recommended to prevent sudden cardiac death in some of these patients. Sleep-disordered breathing (SDB) is highly prevalent in this population and may impact arrhythmogenicity. We performed a systematic review and meta-analysis of prospective studies that assessed the impact of SDB on ICD therapy. METHODS AND RESULTS: Relevant prospective studies were identified in the Ovid MEDLINE, EMBASE, and Google Scholar databases. Weighted risk ratios of the association between SDB and appropriate ICD therapies were estimated using random effects meta-analysis. Nine prospective cohort studies (n=1274) were included in this analysis. SDB was present in 52% of the participants. SDB was associated with a 55% higher risk of appropriate ICD therapies (45% versus 28%; risk ratio, 1.55; 95% confidence interval, 1.32-1.83). In a subgroup analysis based on the subtypes of SDB, the risk was higher in both central (risk ratio, 1.50; 95% confidence interval, 1.11-2.02) and obstructive (risk ratio, 1.43; 95% confidence interval, 1.01-2.03) sleep apnea. CONCLUSIONS: SDB is associated with an increased risk of appropriate ICD therapy in patients with heart failure and reduced ejection fraction.

Preoperative Pectoralis Muscle Quantity and Attenuation by Computed Tomography Are Novel and Powerful Predictors of Mortality After Left Ventricular Assist Device Implantation.

BACKGROUND: Skeletal muscle mass decreases in end-stage heart failure and is predictive of clinical outcomes in several disease states. Skeletal muscle attenuation and quantity as quantified on preoperative chest computed tomographic scans may be predictive of mortality after continuous flow (CF) left ventricular assist device (LVAD) implantation. METHODS AND RESULTS: A single-center continuous flow-LVAD database (n=354) was used to identify patients with chest computed tomographies performed in the 3 months before LVAD implantation (n=143). Among patients with computed tomography data available, unilateral pectoralis muscle mass indexed to body surface area and attenuation (approximated by mean Hounsfield units [PHUm]) were measured in each patient with a high intrarater and inter-rater reliability (intraclass correlation coefficients 0.98 and 0.97, respectively). Multivariate Cox regression analyses were performed, censoring at cardiac transplantation, to assess the impact of preoperative pectoralis muscle index and pectoralis muscle mean Hounsfield unit on survival after LVAD implantation. Each unit increase in pectoralis muscle index was associated with a 27% reduction in the hazard of death after LVAD (adjusted hazard ratio, 0.73; 95% confidence interval, 0.58-0.92; P=0.007). Each 5-U increase in pectoralis muscle mean Hounsfield unit was associated with a 22% reduction in the hazard of death after LVAD (adjusted hazard ratio, 0.78; 95% confidence interval, 0.68-0.89; P<0.0001). Pectoralis muscle index and pectoralis muscle mean Hounsfield unit outperformed other traditional measures in the data set, including the HeartMate II risk score. CONCLUSIONS: Pectoralis muscle size and attenuation were powerful predictors of outcomes after LVAD implantation in this data set. This one time, repeatable, internal assessment of patient substrate added valuable prognostic information that was not available on standard preoperative testing.

Effect of Coronary Artery Bypass Grafting on Left Ventricular Ejection Fraction in Men Eligible for Implantable Cardioverter-Defibrillator.

Implantable cardioverter-defibrillator (ICD) therapy for primary prevention of sudden cardiac death is not routinely recommended within 90 days of coronary artery bypass grafting (CABG) because of the possibility of an improvement in left ventricular ejection fraction (EF) to>35% after revascularization. We sought to determine the incidence and predictors of EF improvement to >35% after isolated CABG in patients who had a preoperative EF ≤35%. We studied 375 patients who underwent CABG at a tertiary institution and had an echocardiogram preoperatively and postoperatively. Of these, 74 patients (20%) with a preoperative EF ≤35% were included in this analysis. Improvement in EF was defined as postoperative EF >35%. In the overall study population (n = 74), mean EF improved from 28 ± 6% preoperatively to 36 ± 12% postoperatively (p <0.0001). A total of 38 patients (51%) had postoperative improvement in EF to >35% (mean EF in these patients increased from 30 ± 5% to 46 ± 8%; p <0.0001). Patients with EF improvement had a higher preoperative EF than those with no improvement (30 ± 5% vs 26 ± 7%, p <0.005). Improvement in EF was 5 times more likely in patients with preoperative EF 26% to 35% (odds ratio 4.95, 95% CI 1.73 to 14.1; p = 0.003) than those with preoperative EF ≤25%. Other clinical characteristics were not significantly different between patients with versus without EF improvement. In conclusion, more than half of the ICD-eligible patients who underwent CABG improved their EF to >35% after surgery and became ineligible for a primary prevention ICD. EF improvement was unlikely in patients with preoperative EF <25%.

Long-Term Outcomes of Patients Who Had Cardiac Arrest After Cardiac Operations.

BACKGROUND: Cardiac arrest after cardiac procedures has a case fatality rate of approximately 60%. However, the long-term risk of death and outcomes among survivors of postoperative cardiac arrest is less clear. METHODS: We examined the mortality and outcomes of 6,979 consecutive patients who underwent cardiac operations from 1991 to 2014 in the Minneapolis Veterans Affairs Health Care System. RESULTS: Cardiac arrest occurred in 182 patients (2.6%) at a median of 3 days (range, 0 to 39 days) after the operation. Of these, 93 (51%) died during the same hospitalization, and an additional 24 (13%) died within 1 year. Mortality at 30 days (51% vs 1.9%; p < 0.0001), at 1 year (64% vs 6%; p < 0.0001), and after a mean follow-up of 7.5 ± 5.5 years (81% vs 34%; p < 0.0001), was higher in those with vs without cardiac arrest. After adjusting for age, sex, year, and type of operation, an in-hospital cardiac arrest was associated with a 4.7-times (95% confidence interval [CI], 3.9 to 5.6; p < 0.0001) higher risk of long-term death in the entire cohort, 2.0-times (95% CI, 1.6 to 2.7; p < 0.0001) higher risk among those who survived 30 days, and 1.3-times (95% CI, 0.9 to 1.9; p = 0.14) higher risk among those who survived 1 year after the operation. Being discharged to a facility (hazard ratio, 3.97; 95% CI, 1.52 to 10.32; p = 0.005) and renal dysfunction (hazard ratio, 3.35; 95% CI, 1.42 to 7.89; p = 0.006) were independent predictors of death amongst cardiac arrest survivors. CONCLUSIONS: Long-term mortality remains high in patients discharged alive after postoperative cardiac arrest. Discharge disposition and renal dysfunction after cardiac arrest have important prognostic implications.