Long-term Outcomes of Percutaneous Coronary Intervention in Patients with Prior Coronary Artery Bypass Grafting.

BACKGROUND Patients with a prior coronary artery bypass graft (CABG) may have a need for repeat revascularization, which is typically attempted first via percutaneous coronary intervention (PCI) of either a bypass graft or native vessel. Long-term outcomes of native vessel compared to graft PCI after CABG have not yet been explored in a large institution study. METHODS Patients with history of prior CABG who underwent PCI at our institution during 2010-2018 were included. Baseline characteristics and long-term outcomes of up to 5 years were compared between native vessel and bypass graft PCI groups. Cox regression was used to adjust for significant covariates in estimation of risk and calculation of hazard ratios. RESULTS During the study, 4,251 patients with a prior CABG underwent PCI. Native vessel PCI represented 67.1% (n=2,851) of the cohort. After adjusting for significant covariates, bypass graft PCI compared to native vessel PCI had a higher risk of overall mortality (HR 1.15; 95% CI, 1.04-1.29; p<0.05), all-cause readmission (HR 1.16; 95% CI, 1.1-1.3; p<0.05), readmission for PCI (HR 1.25; 95% CI, 1.13-1.38; p<0.05), readmission for heart failure (HR 1.16; 95% CI, 1.06-1.26; p<0.05), and composite of myocardial infarction and revascularization (HR 1.23; 95% CI, 1.12-1.35; p<0.05). CONCLUSIONS Among patients with prior CABG, bypass graft PCI compared to native vessel PCI was associated with higher risk of adverse long-term outcomes.

Subclinical myocardial injury and cardiovascular mortality: Racial differences in prevalence and risk (from the third National Health and Nutrition Examination survey).

BACKGROUND: Subclinical myocardial injury (SCMI) determined from the Electrocardiographic Cardiac Infarction/Injury Score (CIIS) is associated with increased risk of cardiovascular disease and mortality. We hypothesized that SCMI prevalence and association with mortality would differ by race, categorized as non-Hispanic White (White), non-Hispanic Black (Black), and Mexican American. METHODS: Our analysis included 5,852 participants (age 58.5 ± 13.2 years; 54% women, 52% Whites, 23% Blacks, and 25% Mexican American participants) from the National Health and Nutrition Examination Survey (NHANES III, 1988-94) who were free of cardiovascular disease at the time of enrollment. SCMI was defined as the presence of CIIS ≥ 10 score points on the 12-lead ECG. Prevalence of SCMI and its association with cardiovascular mortality were examined in each race/ethnic group in models adjusted for sociodemographics and common cardiovascular risk factors. RESULTS: SCMI prevalence was 23.4% in Whites, 21.8% in Blacks, and 18.0% in Mexican Americans. Compared to Whites, Blacks were as likely to have SCMI (odds ratio [OR] 0.95, 95% confidence interval [CI] 0.80-1.13), while Mexican Americans were less likely (OR 0.74, 95% CI 0.62-0.88). SCMI was not associated with increased risk of cardiovascular mortality in either Whites (hazard ratio [HR] 1.18, 95% CI 0.95-1.48) or Blacks (HR 1.19, 95% CI 0.79-1.80). In contrast, SCMI in Mexican Americans was associated with increased risk of cardiovascular mortality (HR 1.74, 95% CI 1.13-2.67, p < .05). CONCLUSION: Mexican Americans had a lower prevalence of SCMI, but increased risk of cardiovascular mortality. Screening for SCMI may identify individuals at increased risk and improve targeted prevention efforts.

Frontal QRS-T Angle and the Risk of Atrial Fibrillation in the Elderly.

BACKGROUND: Frontal QRS-T angle reflects changes in regional action potential duration and the direction of repolarization. Although it has been suggested that abnormal ventricular repolarization predisposes to atrial arrhythmias, it is unknown whether abnormal frontal QRS-T angle is associated with an increased risk of atrial fibrillation (AF). METHODS: We examined the association between frontal QRS-T angle and AF in 4282 participants (95% white; 41% male) from the Cardiovascular Health Study (CHS). QRS-T angle was computed from baseline electrocardiogram data. Abnormal QRS-T angle was defined as values greater than the sex-specific 95th percentile (men >131°; women: >104°). AF cases were identified from study electrocardiograms and from hospitalization discharge data through December 31, 2010. Cox regression was used to compute hazard ratios (HR) and 95% confidence intervals (CI) for the association between abnormal QRS-T angle and AF. RESULTS: Over a median follow-up of 12.1 years, a total of 1276 (30%) participants developed AF. In a Cox regression model, adjusted for socio-demographics and known AF risk factors, abnormal QRS-T angle was associated with a 55% increased risk of AF (HR = 1.55, 95%CI = 1.23, 1.97). When QRS-T angle was examined as a continuous variable, each 10° increase was associated with a 3% increased risk of AF (HR = 1.03, 95%CI = 1.01, 1.05). This finding was consistent in subgroups stratified by age, sex, and race. CONCLUSION: Our findings suggest that an abnormal frontal QRS-T angle on the electrocardiogram provides important prognostic information regarding AF risk in the elderly, and further implicate ventricular repolarization abnormalities in the pathogenesis of AF.

Atrial Fibrillation and Cardiovascular Outcomes in the Elderly.

BACKGROUND: Prior studies have not examined which cardiovascular outcomes most frequently develop in participants with atrial fibrillation (AF) from population-based cohorts of the elderly. METHODS: This analysis included 4,304 (85% white; 61% women) participants from the Cardiovascular Health Study who were free of baseline cardiovascular disease. AF cases were identified at baseline and as time-updated events during follow-up. Kaplan-Meier estimates were used to compute the 1-, 5-, 10-, and 15-year cumulative incidence rates of the following outcomes: coronary heart disease (CHD), myocardial infarction (MI), heart failure, and ischemic stroke. Cox regression was used to compute hazard ratios (HR) and 95% confidence intervals (CI) for the association between AF and each outcome. RESULTS: For all time periods, the cumulative incidence estimates of CHD, MI, heart failure, and ischemic stroke were higher for those with AF compared with those without AF. Heart failure was the most frequent outcome in those with AF, while CHD events were the most frequently detected outcome in participants without AF. Compared with persons who did not have AF, the risk of heart failure was higher in those with AF (HR = 3.18, 95% CI = 2.78-3.64), and the magnitude of this association was greater than the other outcomes of interest (CHD: HR = 1.76, 95% CI = 1.54-2.03; MI: 1.40, 95% CI = 1.14-1.71; ischemic stroke: HR = 1.98, 95% CI = 1.63-2.39). CONCLUSIONS: AF is associated with several adverse cardiovascular outcomes and heart failure is the most frequently detected event. Potentially, risk factor modification strategies for the primary prevention of heart failure will reduce the morbidity and mortality associated with AF.

The Influence of Left Atrial Enlargement on the Relationship between Atrial Fibrillation and Stroke.

BACKGROUND: Left atrial enlargement (LAE) is independently associated with an increased risk of stroke and atrial fibrillation (AF). The combination of both LAE and AF possibly increases the risk of stroke beyond that observed with AF. METHODS: This analysis included 4572 (43% men, 95% white) participants from the Cardiovascular Health Study. LAE was defined using transthoracic echocardiographic 2-dimensional M-mode measurements of the left atrial diameter using sex-specific cut-points (men: ≥4.1 cm, women: ≥3.9 cm). AF cases were identified during the initial study electrocardiogram or by self-reported history. We examined the association between baseline AF and incident ischemic stroke stratified by the presence of LAE. Incident cases of ischemic stroke were identified by adjudication of medical records, including hospitalization data, through December 31, 2010. RESULTS: At baseline, a total of 253 (5.5%) participants had AF and 1947 (43%) had LAE. Participants with AF (n = 163, 64%) were more likely to have LAE than those without AF (n = 1784, 41%; P < .001). Over a median follow-up of 13 years, 739 (16%) ischemic stroke events were identified. Both AF (hazard ratio [HR] = 2.12, 95% confidence interval [CI] = 1.64-2.74) and left atrial diameter (per 1-cm increase: HR = 1.14, 95% CI = 1.01-1.28) were associated with an increased risk for ischemic stroke. The association between AF and ischemic stroke was not modified by the presence of LAE (LAE: HR = 2.13, 95% CI = 1.42-3.19; no LAE: HR = 1.91, 95% CI = 1.36-2.68; P interaction = .86). CONCLUSION: Our results suggest that echocardiographic LAE does not modify the stroke risk observed with AF.

Association of Race and Ethnicity on the Management of Acute Non-ST-Segment Elevation Myocardial Infarction.

Background Prior studies have reported disparities by race in the management of acute myocardial infarction (MI), with many studies having limited covariates or now dated. We examined racial and ethnic differences in the management of MI, specifically non-ST-segment-elevation MI (NSTEMI), in a large, socially diverse cohort of insured patients. We hypothesized that the racial and ethnic disparities in the receipt of coronary angiography or percutaneous coronary intervention would persist in contemporary data. Methods and Results We identified individuals presenting with incident, type I NSTEMI from 2017 to 2019 captured by a health claims database. Race and ethnicity were categorized by the database as Asian, Black, Hispanic, or White. Covariates included demographics (age, sex, race, and ethnicity); Elixhauser variables, including cardiovascular risk factors and other comorbid conditions; and social factors of estimated annual household income and educational attainment. We examined rates of coronary angiography and percutaneous coronary intervention by race and ethnicity and income categories and in multivariable-adjusted models. We identified 87 094 individuals (age 73.8±11.6 years; 55.6% male; 2.6% Asian, 13.4% Black, 11.2% Hispanic, 72.7% White) with incident NSTEMI events from 2017 to 2019. Individuals of Black race were less likely to undergo coronary angiography (odds ratio [OR], 0.93; [95% CI, 0.89-0.98]) and percutaneous coronary intervention (OR, 0.86; [95% CI, 0.81-0.90]) than those of White race. Hispanic individuals were less likely (OR, 0.88; [95% CI, 0.84-0.93]) to undergo coronary angiography and percutaneous coronary intervention (OR, 0.85; [95% CI, 0.81-0.89]) than those of White race. Higher annual household income attenuated differences in the receipt of coronary angiography across all racial and ethnic groups. Conclusions We identified significant racial and ethnic differences in the management of individuals presenting with NSTEMI that were marginally attenuated by higher household income. Our findings suggest continued evidence of health inequities in contemporary NSTEMI treatment.

Interrelations Between Hypertension and Electrocardiographic Left Ventricular Hypertrophy and Their Associations With Cardiovascular Mortality.

Electrocardiogram (ECG) is the most common method for assessment of left ventricular hypertrophy (LVH) in contemporary clinical trials. However, our understanding of the relation between hypertension and LVH is based on studies used imaging to ascertain LVH. To fill this gap in knowledge, we examined the interrelationships between hypertension, ECG-LVH and cardiovascular disease (CVD) mortality in 6,105 patients free of CVD who were followed for 14.0 years (median). The was an exponentianl ECG-LVH prevalence rates (2.40%, 4.45%, 5.75%, 8.51%, 14.38%) were exponentially increases as systolic blood pressure increases (<120 mm Hg, 120 to 129 mm Hg, 130 to 139 mm Hg, 140 to 159 mm Hg, >160 mm Hg, respectively); trend p value <0.001. Hypertension was associated with more than double the risk of ECG-LVH (odds ratio (95% confidence interval [CI]) 2.45 [1.83, 3.30]), and each standard-deviation increase in systolic blood pressure (19 mm Hg) was associated with 49% increased odds of ECG-LVH (odds ratio [95% CI] 1.49 [1.38, 1.61]). During follow-up, 733 CVD-deaths occurred. In separate Cox models, both ECG-LVH and hypertension were associated with CVD mortality (hazard ratio [95% CI] 1.39 [1.07, 1.81] and 1.39 [1.18, 1.62], respectively). However, when ECG-LVH and hypertension were entered together in the same model, the risk of CVD mortality was essentially unchanged for hypertension after adjusting for ECG-LVH, but markedly attenuated for ECG-LVH after adjusting for hypertension. In conclusion, the relation between hypertension and ECG-LVH follows a similar pattern to that reported in literature for imaging-LVH which provides support for the current practice of using ECG for assessment of LVH in contemporary hypertension clinical trials. The inability of ECG-LVH to explain the association between hypertension and CVD mortality suggests that LVH is only one of many factors by which hypertension exerts its impact on CVD.

The clinical utility of normal findings on noninvasive cardiac assessment in the prediction of atrial fibrillation.

BACKGROUND: The absence of abnormalities on noninvasive cardiac assessment possibly confers a reduced risk of atrial fibrillation (AF) despite the presence of traditional risk factors. HYPOTHESIS: Normal findings on noninvasive cardiac assessment are associated with a lower risk of AF development. METHODS: We examined the clinical utility of normal findings on routine noninvasive cardiac assessment in 5331 participants (85% white; 57% women) from the Cardiovascular Health Study who were free of baseline AF. The combination of a normal electrocardiogram (ECG) + normal echocardiogram was assessed for the development of AF events. A normal ECG was defined as the absence of major or minor Minnesota code abnormalities. A normal echocardiogram was defined as the absence of contractile dysfunction, wall motion abnormalities, or abnormal left ventricular mass. Cox regression was used to compute the 10-year risk of developing AF. RESULTS: During the 10-year study period, a total of 951 (18%) AF events were detected. A normal ECG (multivariable hazard ratio [HR]: 0.80, 95% confidence interval [CI]: 0.69-0.92) and normal echocardiogram (multivariable HR: 0.75, 95% CI: 0.65-0.87) were associated with a reduced risk of AF in isolation. This association improved in those with normal ECG + normal echocardiogram (multivariable HR: 0.66, 95% CI: 0.55-0.79) compared with participants who had abnormal ECG + abnormal echocardiogram (referent). CONCLUSIONS: Normal findings on routine noninvasive cardiac assessment identify persons in whom the risk of AF is low. Further studies are needed to explore the utility of this profile regarding the decision to implement certain risk factor modification strategies in older adults to reduce AF burden.

Utility of Normal Findings on Electrocardiogram and Echocardiogram in Subjects ≥65 Years.

The lack of abnormalities found on noninvasive cardiac testing possibly improves cardiovascular disease (CVD) risk stratification efforts and conveys reduced risk despite the presence of traditional risk factors. This analysis included 3,805 (95% white and 61% women) participants from the Cardiovascular Health Study (CHS) without baseline CVD. The combination of a normal electrocardiogram (ECG) and echocardiogram was assessed for the development of CVD. A normal ECG was defined as the absence of major or minor Minnesota code abnormalities. A normal echocardiogram was defined as the absence of contractile dysfunction, wall motion abnormalities, or abnormal left ventricular mass. Cox regression was used to compute the 10-year risk of developing coronary heart disease, stroke, and heart failure events. There were 1,555 participants (41%) with normal findings on both measures. After accounting for traditional CVD risk factors, a protective benefit was observed for all outcomes among participants who had normal ECG and echocardiographic findings (coronary heart disease: hazard ratio [HR] 0.56, 95% confidence interval [CI] 0.46, 0.69; stroke: HR 0.57, 95% CI 0.43, 0.76; heart failure: HR 0.36, 95% CI 0.29, 0.41). The addition of this normal profile resulted in significant net reclassification improvement of the Framingham risk score for heart failure (net reclassification improvement 4.3%, 95% CI 1.0, 8.0). In conclusion, normal findings on routine noninvasive cardiac assessment identify subjects in whom CVD risk is low.

Normal findings on noninvasive cardiac assessment and the prediction of heart failure: The Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND: It is unknown if normal findings on noninvasive cardiac assessment are able to identify individuals who are low risk for developing heart failure (HF). METHODS: We examined if normal findings on the routine electrocardiogram (ECG) and cardiac magnetic resonance imaging (MRI) were able to identify individuals who are low risk for developing HF in 4986 (mean age=62±10years; 52% women; 39% White; 13% Chinese-American; 26% Black; 22% Hispanic) participants from the Multi-Ethnic Study of Atherosclerosis who were free of clinically apparent HF at baseline. A normal ECG was defined as the absence of major abnormalities by Minnesota Code Classification, and a normal MRI was defined as absence of structural abnormalities and systolic dysfunction. RESULTS: There were 3988 (80%) participants with normal findings at baseline on both ECG and MRI, 894 (18%) who had either a normal ECG or normal MRI, and 104 (2%) who had abnormal findings on ECG and MRI. Over a median follow-up of 12.2years, 177 (3.6%) HF events occurred. Normal ECG (HR=0.41, 95%CI=0.29, 0.56) and MRI (HR=0.32, 95%CI=0.23, 0.45) were each associated with lower risk of HF compared with abnormal, and their combination was associated with a lower HF risk (HR=0.13, 95%CI=0.08, 0.21) than either in isolation. CONCLUSION: Normal findings on noninvasive cardiac assessment identify individuals in whom the risk of HF is low. Further studies are needed to explore the utility of this low-risk profile in HF prevention strategies.

Biomarkers and the prediction of atrial fibrillation: state of the art.

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice, and it places a substantial burden on the health care system. Despite improvements in our understanding of AF pathophysiology, we have yet to develop targeted preventive therapies. Recently, numerous biological markers have been identified to aid in the prediction of future AF events. Subclinical markers of atrial stress, inflammation, endothelial dysfunction, kidney dysfunction, and atherosclerosis have been linked to AF. The connection between these markers and AF is the identification of subclinical states in which AF propagation is likely to occur, as these conditions are associated with abnormal atrial remodeling and fibrosis. Additionally, several risk scores have been developed to aid in the identification of at-risk patients. The practicing clinician should be aware of these subclinical markers, as several of these markers improve the predictive abilities of current AF risk scores. Knowledge of these subclinical markers also provides clinicians with a better understanding of AF risk factors, and the opportunity to reduce the occurrence of AF by incorporating well-known cardiovascular disease risk factor modification strategies. In this review, we highlight several novel biological markers that have improved our understanding of AF pathophysiology and appraise the utility of these markers to improve our ability to predict future AF events.