Bonikowske, Amanda R.

Introduction: Cardiac rehabilitation (CR) is associated with improvements in exercise capacity (peak oxygen uptake (VO 2 peak)); however, 23% of CR patients do not improve VO 2 peak following CR. CR adherence (i.e. number of CR sessions attended) has been proposed to play an important role in VO 2 peak improvement following CR, but has not been investigated. Identifying clinical predictors of VO 2 peak improvement are critical as the degree of VO 2 peak improvement is associated with improved long-term outcomes in these patients. Purpose: To determine if clinical characteristics and number of CR sessions attended were predictive of patients who exhibited improvement in VO 2 peak following CR. Methods: Using the Rochester Epidemiology Project records-linkage system, we identified all consecutive patients >18 years old from Olmsted County, Minnesota who underwent cardiopulmonary exercise testing prior to and following CR from 1999 to 2017. Regression models were created to assess clinical predictors of VO 2 peak improvement (>0% baseline) following CR. Results: The analysis included 804 patients (75% men) with a mean age of 60.7±12.4 years. Of the 804 patients, 609 (76%) patients exhibited VO 2 peak improvement following CR. Significant univariate predictors of VO 2 peak improvement included younger age (OR: 0.99, 95% CI: 0.97-1.00), lower pre-CR VO 2 peak (OR: 0.97, 95% CI: 0.94-0.99), history of peripheral artery disease (OR: 0.48, 95% CI: 0.32-0.73), and smoking (OR: 0.63, 95% CI: 0.45-0.90). Significant independent predictors of VO 2 peak improvement from a multivariate analysis included younger age (OR: 0.98, 95% CI: 0.96-1.00), number of CR sessions (OR: 1.02, 95% CI: 1.01-1.03), lower pre-CR VO 2 peak (OR: 0.94, 95% CI: 0.91-0.96), history of peripheral artery disease (OR: 0.42, 95% CI: 0.27-0.66), and smoking (OR: 0.56, 95% CI: 0.39-0.82). Conclusions: These findings demonstrate the importance of CR adherence and individual clinical characteristics in influencing VO 2 peak improvement following CR in patients with CVD. These findings may influence the clinical practice by providing specific clinical characteristics to account for when personalizing the CR treatment plan to maximize positive outcomes.

Background There is wide variability in cardiac rehabilitation (CR) dose (ie, number of sessions) delivered, and no evidence‐based recommendations regarding what dose to prescribe. We aimed to test what CR dose impacts major adverse cardiovascular events (MACEs). Methods and Results This is an historical cohort study of all patients who had coronary artery disease and who initiated supervised CR between 2002 and 2012 from a single major CR center. CR dose was defined as number of visits including exercise and patient education. Follow‐up was performed using record linkage from the Rochester Epidemiology Project. MACEs included acute myocardial infarction, unstable angina, ventricular arrhythmias, stroke, revascularization, or all‐cause mortality. Dose was analyzed in several ways, including tertiles, categories, and as a continuous variable. Cox models were adjusted for factors associated with dose and MACE. The cohort consisted of 2345 patients, who attended a mean of 12.5±11.1 of 36 prescribed sessions. After a mean follow‐up of 6 years, 695 (29.65%) patients had a MACE, including 231 who died. CR dose was inversely associated with MACE (hazard ratio, 0.66 [95% CI]; 0.55–0.91) in those completing ≥20 sessions, when compared with those not exposed to formal exercise sessions (≤1 session; log‐rank P =0.007). We did not find evidence of nonlinearity ( P ≥0.050), suggesting no minimal threshold nor ceiling. Each additional session was associated with a lower rate of MACE (fully adjusted hazard ratio, 0.98 [95% CI, 0.97–0.99]). Greater session frequency was also associated with lower MACE risk (fully adjusted hazard ratio, 0.74 [95% CI, 0.58–0.94]). Conclusions CR reduces MACEs, but the benefit appears to be linear, with greater risk reduction with higher doses, and no upper threshold.

ABSTRACT Objective This study aimed to examine the effect on continuously monitored blood glucose (BG) among participants with impaired fasting glucose (IFG) who used a height-adjustable desk while working. Methods The study was a repeated-measures pilot study in overweight or obese women who had IFG (BG >100 mg·dL −1 ) and a sedentary job. BG was monitored with continuous glucose monitoring devices during two 1-wk periods at work: 1 wk in the seated position and 1 wk using alternate bouts of sitting and standing (by adjusting their desks) throughout the workday. Results Ten women completed the study. Sedentary time significantly predicted BG independently of diet and overall physical activity ( P = 0.02). Dietary carbohydrates, protein, and fat were significant predictors of BG ( P < 0.001). Conclusions Sedentary time is a strong predictor of increased BG in women with IFG and a sedentary job.

Introduction: Body fat (BF) content better predicts adiposity-related cardiovascular risk than the body mass index (BMI). Accurate and accepted methods to assess BF are complex, expensive, and accessible only in clinical settings. Multi-sensor 3D body volume (3D-BV) measurement technology has been shown to accurately estimate BF. We assessed the hypothesis that 3D models generated from biplane imaging (i.e., front and side facing photographs) using mobile devices (App), could be used to predict body volume measurements and derive BF. Methods: We prospectively enrolled 196 subjects, who underwent 3D-BV (gold standard for body volume) within 24 hours, dual-energy X-ray Absorptiometry (iDEXA) (gold standard for BF) and photographs taken with an Ipad® App at a predefined distance and pose. These photos were post-processed with a computer-assisted algorithm to estimate body length, girth, and volume. These were used to calculate body density (BD) using the bicompartmental principles of body composition (BD=Body Mass/Volume) and derive BF% using the Siri equation [(4.95/BD-4.50) X 100]. Correlation indexes and residual plots were created to compare 3D-BV and iDEXA with the App. Mean differences were compared using a paired t-test. Results: Mean ±SD age was 31.9±9.15 years, 53% were women, weight 72.8±14.1 kg, BMI was 25.5±4.5 kg/m 2 .The App volume correlated with 3D-BV (R 2 =0.95,95%CI 0.90,0.95, p<.0001, Figure 1-A ) ; average difference between App volume vs 3D-BV volume was -1.2 Liters, 95%CI,0.03, 2.42, p=0.06, ( Figure 1-B ). App BF% correlated with iDEXA BF% (R 2 =0.92, 95%CI 0.90,0.94, p<.0001, Figure 1-C ) ; while average difference between App BF% vs iDEXA BF% was -0.13 %, 95%CI -0.6,0.4, p=0.6, ( Figure 1-D ). Conclusion: BF can be estimated using volume measurements obtained by biplane imaging from mobile devices and could serve as a home-based, portable, scalable, cost-effective, and convenient measure to assess BF and track changes in body composition over time.

Introduction: Spontaneous coronary artery dissection (SCAD) is an important cause of myocardial infarction in otherwise healthy and most times presumably fit young women. In the absence of evidence for benefit or harm, exercise prescription (EXP) after SCAD remains arbitrary. We assessed EXP patterns among participants in a large multinational SCAD registry. Methods: Participants with SCAD as confirmed by coronary angiography completed surveys detailing exercise (EX) habits prior to SCAD (initial survey), and EXP from their provider on initial and subsequent visits after SCAD (follow-up survey). Demographic and clinical characteristics were collected by electronic health record review by trained nurse abstractors. EXP was categorized according to EX components that include: type, intensity, frequency, time/session, and external conditions. Results: Among 950 participants, mean ± age was 46.8 ± 9.5 years, 96% were women and 77% reported attending ≥1 Cardiopulmonary Rehabilitation session. Prior to SCAD, 49% were aerobically exercising ≥ 3times per week, and only 32% performed strength-building EX regularly. Initial and subsequent post-SCAD visit details in 299/950 participants showed that most (93%) patients received some form of EX (Figure 1-A) counseling, namely: EXP, unspecific advice or were discouraged from any EX (Figure 1-B) . Limits regarding EX type and intensity were the most common advice received among EXP group (Figure 1-C) . Conclusions: Insights from our study show that only 40% of patients were achieving current exercise recommendations for adults prior to SCAD (vs 53% adult U.S population; CDC, 2018) which suggests that SCAD patients may not be as active as previously described. Most patients receive some form of EX counseling after SCAD; however, a structured EXP is needed to avoid overly cautious approaches that could lead to uncertainty, deconditioning, impaired quality of life, or increase risks associated with a sedentary lifestyle.

We sought to update norms for peak systolic blood pressure (SBP) on the graded exercise test and examine its prognostic value in patients without baseline cardiovascular disease. Mayo graded exercise test data (1993–2010) were reviewed for nonimaging tests using Bruce protocol, selecting Minnesota residents 30 to 79 years without baseline cardiovascular disease. We formed a pure cohort of patients without factors significantly affecting peak SBP to determine peak SBP percentile norms by age and sex. Then we divided the full cohort of patients into 5 groups based on peak SBP percentiles: low (<10th), borderline low (10th–25th), referent (25th–75th), borderline high (75th–90th), and high (>90th). The relationship between peak SBP and mortality was tested using Cox regression adjusting for age, sex, and comorbidities affecting peak SBP or mortality. We identified 20 760 eligible patients with 7313 females (35%) and mean age 51.5±10.7 years. Our pure cohort included 7810 patients. Over 12.5±5.0 years follow-up, there were 1582 deaths, including 541 cardiovascular deaths. In the fully adjusted model, low-peak SBP was associated with increased total mortality (heart rate, 1.41 [1.19–1.66], P <0.0001) and cardiovascular mortality (heart rate, 1.54 [1.16–2.03], P =0.001), while borderline low-peak SBP was associated with increased cardiovascular mortality only (heart rate, 1.36 [1.02–1.81], P =0.027). High peak SBP was associated with increased total mortality only in the age-sex adjusted model (heart rate, 1.18 [1.02–1.36], P =0.026), not after full adjustment. We conclude that low exercise peak SBP is an independent predictor of higher total and cardiovascular mortality.

Abstract Background Exercise intolerance is the cardinal manifestation of heart failure (HF), yet its underlying mechanism(s) remain poorly understood. Measures of ventricular function such as ejection fraction often have no relationship with exercise capacity in HF. 2D-STE has proved to be more reliable method to evaluate myocardial mechanical function. Our hypothesis is Resistance exercise training (Resist-HFpEF) will improve exercise tolerance and exertional symptoms in patients with HFpEF. Purpose The study aims to evaluate myocardial mechanical function by strain imaging during resistance exercise training in Heart Failure patients with Preserved Ejection Fraction (HFpEF) Methods This is a single centre prospective pilot study. 24 HFpEF patients were enrolled and their baseline comorbidities were recorded. Baseline 2D-STE imaging was performed at rest and during exercise (Visit 1). Patients were then randomized to either a novel resistance exercise training program for 36 sessions (3 sessions per week for 12 weeks) or a standard of care control group. 2D STE imaging was then repeated at follow-up (Visit 2). Peak Global Longitudinal strain (GLS), systolic strain rate (SSR), early diastolic strain rate (SRe) were measured offline. Results Mean age of the Rehab cohort was 68.57±10.52 years and the control cohort was 68.1±6.47 years. 23 study subjects were male (96%). 17% of the study subjects were hypertensive, 63% were diabetic, 42% had NYHA I, 46% had NYHA II and 13% had NYHA III of heart failure. The mean LV ejection fraction in the control and Rehab group after the training program at rest was 61.88±2.26% & 54.74±2.07% (p-value 0.04) and during exercise was 59.90±2.05% and 53.13±2.05% (p-value 0.04). The peak GLS was −18.80±4.29% and −17.7±2.21% in controls during rest and exercise at Visit 1 (p-value 0.27) while the rehab cohort had −18.71±4.7% and −20.82±2.4% respectively (p-value 0.0268). The peak GLS was −17.40±3.05% and −17.96±2.65% in controls during rest and exercise at Visit 2 (p-value 0.3430) while rehab cohort had −17.97±6.21% and −16.57±3.82% respectively (p-value 0.67). (Figure 1a and 1b shows GLS, SRS, SRe at Baseline and after exercise program respectively) Conclusion This pilot study suggest systolic and diastolic reserve can be measured reliably during low grade exercise. These results could reflect improvement in clinical status and exercise tolerance. Figure 1. Comparison of peak GLS, SSR, SRe amongst HFpEF patients at rest and during exercise before and after the rehab training program. Funding Acknowledgement Type of funding source: None

Calf muscle pump (CMP) promotes venous return from the lower extremity and contributes to preload and cardiac output. Impaired CMP function may reflect a measure of frailty or cumulative disease burden or may impede cardiac function. The study objective was to test the hypothesis that impaired CMP negatively impacts survival. Consecutive adult patients who underwent venous strain gauge plethysmography at the Mayo Clinic Gonda Vascular Laboratory (January 1, 1998 – December 31, 2011) were assessed for overall survival. Patients with venous incompetence, venous obstruction or unilateral calf pump dysfunction were excluded. Risk of mortality was assessed with Cox proportional hazard ratios and after adjusting for Charlson Comorbidity Index variables. Over the study period, 2728 patients were included in the analysis. Compared to patients with normal CMP, those with impaired CMP were older ( p < 0.001), predominantly female ( p = 0.01) and had higher mean Charlson scores ( p < 0.001). Patients with impaired CMP had a higher mortality rate at 5 (8.9% vs 2.4%), 10 (17.5% vs 5.9%), and 15 years (22.8% vs 8.3%) compared to those with normal CMP ( p < 0.001 for each comparison). Of patients with heart failure, those with impaired CMP had worse survival at each 5-year increment compared to those with normal CMP ( p < 0.05 at each increment). In conclusion, impaired CMP appears to be an independent predictor of poor outcomes after adjusting for variables within the Charlson Comorbidity Index. The association between impaired CMP, heart failure, and mortality may represent a negative impact on circulatory function or a surrogate measure of frailty.

Background Right bundle‐branch block (RBBB) occurs in 0.2% to 1.3% of people and is considered a benign finding. However, some studies have suggested increased risk of cardiovascular morbidity and mortality. We sought to evaluate risk attributable to incidental RBBB in patients without prior diagnosis of cardiovascular disease (CVD). Methods and Results We reviewed the Mayo Clinic Integrated Stress Center database for exercise stress tests performed from 1993 to 2010. Patients with no known CVD—defined as absence of coronary disease, structural heart disease, heart failure, or cerebrovascular disease—were selected. Only Minnesota residents were included, all of whom had full mortality and outcomes data. There were 22 806 patients without CVD identified; 220 of whom (0.96%) had RBBB, followed for 6 to 23 years (mean 12.4±5.1). There were 8256 women (36.2%), mean age was 52±11 years; and 1837 deaths (8.05%), including 645 cardiovascular‐related deaths (2.83%), occurred over follow‐up. RBBB was predictive of all‐cause (hazard ratio [HR], 1.5; 95% CI, 1.1–2.0; P =0.0058) and cardiovascular‐related mortality (HR,1.7; 95% CI, 1.1–2.8; P =0.0178) after adjusting for age, sex, diabetes mellitus, hypertension, obesity, current and past history of smoking, and use of a heart rate‐lowering drug. Patients with RBBB exhibited more hypertension (34.1% versus 23.7%, P <0.0003), decreased functional aerobic capacity (82±25% versus 90±24%; P <0.0001), slower heart rate recovery (13.5±11.5 versus 17.1±9.4 bpm; P <0.0001), and more dyspnea (28.2% versus 22.4%; P <0.0399) on exercise testing. Conclusions Patients with RBBB without CVD have increased risk of all‐cause mortality, cardiovascular‐related mortality, and lower exercise tolerance. These data suggest RBBB may be a marker of early CVD and merit further prospective evaluation.