Predictors of Exercise Capacity in Patients with Hypertrophic Obstructive Cardiomyopathy

Gender-related differences in left atrial strain mechanics and exercise capacity in hypertrophic cardiomyopathy: a propensity-score matched study from the Cleveland Clinic

Background

Male and female patients with hypertrophic cardiomyopathy (HCM) differ in physiologic characteristics and hemodynamics. Little is known about gender-related differences in left atrial (LA) strain and exercise capacity. The aim of this study was to assess the gender-related differences in the relationship between exercise capacity and cardiac function including LA function in patients with HCM.

Methods

Five hundred and thirty-two patients with HCM undergoing exercise stress echocardiography and cardiopulmonary exercise testing (CPET) were prospectively recruited between October 2015 and April 2019 as part of a cohort study in a quaternary referral center. To reduce potential confounding factors, propensity score (PS) matching was performed in 420 patients. LA strain mechanics were evaluated using speckle-tracking echocardiography.

Results

The majority of patients were male, comprising 58% of the total. Female HCM patients were older (54±14 vs. 50±15 years, P=0.002). After PS matching, percent-predicted peak VO2 was similar between the genders (67.5%±20.7% vs. 65.8%±21.8%, P=0.41), even though female HCM patients had lower peak VO2 (17.7±5.9 vs. 24.1±8.3 mL/kg/min, P<0.001). Left ventricular (LV) diastolic function was worse for female HCM patients. This is shown by worse E/e' ratio (15.0±5.9 vs. 12.9±6.4, P<0.001) and larger LA volume in respect to LV (0.88±0.35 vs. 0.74±0.31, P<0.001), compared with male HCM patients. The gender-related differences in LA reservoir strain were more evident for patients aged 60 years and older (27.5%±8.8% vs. 30.9%±9.1%, P=0.03). LA reservoir strain was found to have a significant association with exercise capacity in both male and female HCM patients (for females, β=0.27, P=0.001; for males, β=0.27, P<0.001), independent of LV diastolic dysfunction and stroke volume.

Conclusions

Gender-related differences in LA reservoir strain were increasingly evident for older HCM patients aged 60 years and older. LA reservoir strain was an independent determinant of percent-predicted peak VO2 in male and female patients, underpinning the importance of LA function in determining exercise capacity in HCM.

Clinical course of adults with co-occurring hypertrophic cardiomyopathy and hypertension: A scoping review

Introduction

Hypertension affects approximately 50 % of patients with hypertrophic cardiomyopathy (HCM) but clinical course in adults with co-occurring HCM and hypertension is underexplored. Management may be challenging as routine anti-hypertensive medications may worsen obstructive HCM, the most common HCM phenotype. In this scoping review, we sought to synthesize the available literature related to clinical course and outcomes in adults with both conditions and to highlight knowledge gaps to inform future research directions.

Methods

We searched 5 electronic databases (PubMed, CINAHL, Scopus, Embase, Web of Science) to identify peer-reviewed articles, 2011-2023. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Scoping Review (PRISMA-ScR) guideline.

Results

Eleven articles met eligibility. Adults with both conditions were older and had higher rates of obesity and diabetes than adults with HCM alone. Results related to functional class and arrhythmia were equivocal in cross-sectional studies. Only 1 article investigated changes in medical therapy among adults with both conditions. Hypertension was a predictor of worse functional class, but was not associated with all-cause mortality, heart failure-related mortality, or sudden-death. No data was found that related to common hypertension-related outcomes, including renal disease progression, nor patient-reported outcomes, including quality of life.

Conclusions

Our results highlight areas for future research to improve understanding of co-occurring HCM and hypertension. These include a need for tailored approaches to medical management to optimize outcomes, evaluation of symptom burden and quality of life, and investigation of hypertension-related outcomes, like renal disease and ischemic stroke, to inform cardiovascular risk mitigation strategies.

Three-dimensional echocardiography for the evaluation of hypertrophic cardiomyopathy patients: relation to symptoms and exercise capacity

Patients with hypertrophic cardiomyopathy may exhibit impaired functional capacity, associated with increased morbidity and mortality. Systolic function is one of the determinants of functional capacity. Early identification of systolic disfunction may identify patients at risk for adverse outcomes. Myocardial deformation parameters, derived from three-dimensional (3D) speckle-tracking echocardiography (3DSTE) are useful tools to assess left ventricular systolic function, and are often abnormal before a decline in ejection fraction is seen. The aim of this study was to evaluate the correlation between myocardial deformation parameters obtained by 3DSTE and functional capacity in patients with hypertrophic cardiomyopathy. Seventy-four hypertrophic cardiomyopathy adult patients were prospectively evaluated. All patients underwent a dedicated 2D and 3D echocardiographic examination and cardiopulmonary exercise testing (CPET). Values of 3D global radial (GRS), longitudinal (3DGLS) and circumferential strain (GCS) were overall reduced in our population: 99% (n = 73) of the patients had reduced GLS, 82% (n = 61) had reduced GRS and all patients had reduced GCS obtain by 3DSTE. Average peak VO2 was 21.01 (6.08) ml/Kg/min; 58% (n = 39) of the patients showed reduced exercise tolerance (predicted peak VO2 < 80%). The average VE/VCO2 slope was 29.0 (5.3) and 16% (n = 11) of the patients had impaired ventilatory efficiency (VE/VCO2 > 34). In multivariable analysis, 3D GLS (β1 = 0.10, 95%CI: 0.03;0.23, p = 0.014), age (β1 = -0.15, 95%CI: -0.23; -0.05, p = 0.002) and female gender (β1 = -5.10, 95%CI: -7.7; -2.6, p < 0.01) were independently associated with peak VO2. No association was found between left ventricle ejection fraction obtain and peak VO2 (r = 0.161, p = 0.5). Impaired myocardial deformation parameters evaluated by 3DSTE were associated with worse functional capacity assessed by peak VO2.

Predictors of Changes in Peak Oxygen Uptake After Outpatient Cardiac Rehabilitation: Importance of Cardiac Rehabilitation Attendance

Objective

To determine whether the number of cardiac rehabilitation (CR) sessions attended and selected clinical characteristics were predictive of patients who exhibited improvement in peak oxygen uptake (VO₂peak) after CR.

Patients and Methods

Using the Rochester Epidemiology Project records-linkage system, we identified all consecutive patients aged 18 years or older from Olmsted County, Minnesota, who underwent cardiopulmonary exercise testing before and after CR from 1999 to 2017. Regression models were created to assess the clinical predictors of VO₂peak improvement (>0% baseline) after CR.

Results

The analysis included 671 patients, of which 524 (78%) patients exhibited VO₂peak improvement after CR. The significant univariate predictors of VO₂peak improvement included younger age (odds ratio [OR], 0.98; 95% CI, 0.96-0.99), lower pre-CR VO₂peak (OR, 0.96; 95% CI, 0.94-0.99), and no history of peripheral artery disease (OR, 0.50; 95% CI, 0.31-0.81) (all, P<.005). The significant independent predictors of VO₂peak improvement from the multivariable analysis included the number of CR sessions (OR, 1.04; 95% CI, 1.02-1.05), younger age (OR, 0.96; 95% CI, 0.94-0.98), lower pre-CR VO₂peak (OR, 0.92; 95% CI, 0.89-0.95), and no history of peripheral artery disease (OR, 0.47; 95% CI, 0.28-0.78) (all, P<.005).

Conclusion

These findings highlight the importance of patient participation in CR sessions and individual clinical characteristics in influencing VO₂peak improvement after CR in patients with cardiovascular disease.

Obstructive and Nonobstructive Hypertrophic Cardiomyopathy: Differences in Global and Segmental Myocardial Strain by Cardiac Magnetic Resonance Feature Tracking

PURPOSE

To evaluate any significant differences in myocardial strain between hypertrophic obstructive cardiomyopathy (HOCM) and nonobstructive ones (HNCM), as assessed by cardiac magnetic resonance feature tracking (CMR-FT).

MATERIALS AND METHODS

A total of 17 patients (mean age: 54±14 y) with echocardiographic diagnosis of HOCM (left ventricular outflow tract obstruction peak gradient ≥30 mm Hg), 19 patients (mean age: 49±16 y) with HNCM (peak gradient <30 mm Hg), and 18 age-matched and gender-matched healthy controls (mean age: 42±14 y). All patients underwent cardiac MRI with SSFP-cine to assess left ventricular global and segmental strain analysis by CMR-FT. Late gadolinium enhancement (LGE) sequences were used for semiautomatic quantification of LGE volume, mass, and percentage.

RESULTS

The magnitude of global radial, circumferential, and longitudinal strain as well as strain rate were significantly lower in all patients in comparison to controls (P<0.001), except for radial and circumferential strain between HOCM and controls (P=0.270; P=0.154). The latter strain parameters were significantly higher in HOCM than HNCM (radial strain: 31.67±7.55 vs. 21.26±7.10, P<0.001; circumferential strain: -17.94±2.78 vs. -13.46±3.42, P<0.001). Radial and circumferential strain and circumferential diastolic strain rate were higher in mid-anterior (P<0.001), mid-anteroseptal (P<0.001), and all apical segments (P<0.005) between the 2 groups of patients. Moreover, longitudinal strain was higher only in apical segments in HOCM (P<0.02).

CONCLUSIONS

HOCM patients showed higher left ventricular apical, mid-anterior, and mid-anteroseptal strain parameters compared with HNCM. These differences were independent of corresponding segmental thickness and LGE amount.

Hypertrophic cardiomyopathies requiring more monitoring for less atrial fibrillation-related complications: a clustering analysis based on the French registry on hypertrophic cardiomyopathy (REMY)

AIMS

Defining the risk of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) patients is an important clinical and prognostic challenge. The aim of this study is to determine HCM phenogroups with different risk of AF occurrence at 5 years.

METHODS AND RESULTS

We applied retrospectively the Bayesian method, which can analyze a large number of variables, to differentiate phenogroups of patients with different risks of AF and prognoses across a French prospective on-going hospital-based registry of adult HCM patients (REMY). Clinical and imaging data were prospectively recorded, and patients were followed for 5 years. A total of 1431 HCM patients were recruited, including 1275 analyzed in the present study after exclusion criteria. The population included 412 women, 369 patients with obstructive HCM, and 252 implanted with an ICD. AF occurred in 167 (11.6%) patients during the 5 year follow-up. Three phenogroups were defined according to their common clinical and echocardiographic characteristics. Patients at the highest risk were oldest, more often female, with more frequent comorbidities, anteroposterior diameter of the left atrium was significantly greater, with diastolic dysfunction, outflow-tract obstruction, and mitral valve abnormality, and presented higher pulmonary artery pressure and/or right-ventricular dysfunction. These also had a higher risk of all-cause hospitalizations and death.

CONCLUSION

Based on a clustering analysis, three phenogroups of HCM according to the risk of AF occurrence can be identified. It can indicate which patients should be more monitored and/or treated, particular to prevent the risk of stroke.

Cardiopulmonary Exercise Test in Patients with Hypertrophic Cardiomyopathy: A Systematic Review and Meta-Analysis

BACKGROUND

Patients with chronic diseases frequently adapt their lifestyles to their functional limitations. Functional capacity in Hypertrophic Cardiomyopathy (HCM) can be assessed by stress testing. We aim to review and analyze the available data from the literature on the value of Cardiopulmonary Exercise Test (CPET) in HCM. Objective measurements from CPET are used for evaluation of patient response to traditional and new developing therapeutic measurements.

METHODS

A systematic review of the literature was conducted in PubMed, Web of Science and Cochrane in Mar-20. The original search yielded 2628 results. One hundred and two full texts were read after the first screening, of which, 69 were included for qualitative synthesis. Relevant variables to be included in the review were set and 17 were selected, including comorbidities, body mass index (BMI), cardiac-related symptoms, echocardiographic variables, medications and outcomes.

RESULTS

Study sample consisted of 69 research articles, including 11,672 patients (48 ± 14 years old, 65.9%/34.1% men/women). Treadmill was the most common instrument employed (n = 37 studies), followed by upright cycle-ergometer (n = 16 studies). Mean maximal oxygen consumption (VO2max) was 22.3 ± 3.8 mL·kg^-1·min^-1. The highest average values were observed in supine and upright cycle-ergometer (25.3 ± 6.5 and 24.8 ± 9.1 mL·kg^-1·min^-1; respectively). Oxygen consumption in the anaerobic threshold (ATVO2) was reported in 18 publications. Left ventricular outflow tract gradient (LVOT) > 30 mmHg was present at baseline in 31.4% of cases. It increased to 49% during exercise. Proportion of abnormal blood pressure response (ABPRE) was higher in severe (>20 mm) vs. mild hypertrophy groups (17.9% vs. 13.6%, p < 0.001). Mean VO2max was not significantly different between severe vs. milder hypertrophy, or for obstructive vs. non-obstructive groups. Occurrence of arrhythmias during functional assessment was higher among younger adults (5.42% vs. 1.69% in older adults, p < 0.001). Twenty-three publications (9145 patients) evaluated the prognostic value of exercise capacity. There were 8.5% total deaths, 6.7% cardiovascular deaths, 3.0% sudden cardiac deaths (SCD), 1.2% heart failure death, 0.6% resuscitated cardiac arrests, 1.1% transplants, 2.6% implantable cardioverter defibrillator (ICD) therapies and 1.2 strokes (mean follow-up: 3.81 ± 2.77 years). VO2max, ATVO2, METs, % of age-gender predicted VO2max, % of age-gender predicted METs, ABPRE and ventricular arrhythmias were significantly associated with major outcomes individually. Mean VO2max was reduced in patients who reached the combined cardiovascular death outcome compared to those who survived (-6.20 mL·kg^-1·min^-1; CI 95%: -7.95, -4.46; p < 0.01).

CONCLUSIONS

CPET is a valuable tool and can safely perform for assessment of physical functional capacity in patients with HCM. VO2max is the most common performance measurement evaluated in functional studies, showing higher values in those based on cycle-ergometer compared to treadmill. Subgroup analysis shows that exercise intolerance seems to be more related to age, medication and comorbidities than HCM phenotype itself. Lower VO2max is consistently seen in HCM patients at major cardiovascular risk.

Impact of left atrial strain mechanics on exercise intolerance and need for septal reduction therapy in hypertrophic cardiomyopathy

AIMS

We sought to assess the relationship between left atrial (LA) strain mechanics and exercise intolerance, and to evaluate the prognostic impact of LA strain mechanics on clinical deterioration necessitating septal reduction therapy in hypertrophic cardiomyopathy (HCM).

METHODS AND RESULTS

Consecutive HCM patients who underwent exercise stress echocardiography and cardiopulmonary exercise testing on the same day between October 2015 and April 2019 were enrolled prospectively. LA strain mechanics were analysed using speckle tracking echocardiography. LA stiffness was calculated as the ratio of E/e' ratio to LA reservoir strain. The study cohort was divided into four groups based on the quartile of percent-predicted peak VO2, and exercise intolerance was defined as the lowest quartile (≤51%). Of 532 patients studied (mean age: 51 ± 15 years, 42% female), 138 patients demonstrated exercise intolerance. As exercise capacity worsened, LA strain mechanics worsened along a continuum (P < 0.001). LA contractile strain with a cut-off of -13.9% was optimal at identifying exercise intolerance. On multivariable analysis, worse LA contractile strain was an independent predictor for exercise intolerance (P = 0.002). Of patients with left ventricular outflow tract obstruction, patients with LA stiffness worse than the median value (≥0.41) were significantly more likely to require septal reduction therapy than those with better LA stiffness (P = 0.026).

CONCLUSION

Worse LA contractile strain was an independent predictor for exercise intolerance in HCM. Patients with worse LA stiffness had a higher probability of clinical deterioration necessitating septal reduction therapy.

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

Aim This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy in adult and pediatric patients as well as supporting documentation to encourage their use. Methods A comprehensive literature search was conducted from January 1, 2010, to April 30, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Structure Many recommendations from the earlier hypertrophic cardiomyopathy guidelines have been updated with new evidence or a better understanding of earlier evidence. This summary operationalizes the recommendations from the full guideline and presents a combination of diagnostic work-up, genetic and family screening, risk stratification approaches, lifestyle modifications, surgical and catheter interventions, and medications that constitute components of guideline directed medical therapy. For both guideline-directed medical therapy and other recommended drug treatment regimens, the reader is advised to follow dosing, contraindications and drug-drug interactions based on product insert materials.

The Role of Cardiac Rehabilitation in Reducing Major Adverse Cardiac Events in Heart Transplant Patients

BACKGROUND

Methods for reducing major adverse cardiac events (MACE) in patients after heart transplantation (HTx) are critical for long-term quality outcomes.

METHODS AND RESULTS

Patients with cardiopulmonary exercise testing prior to HTx and at least 1 session of cardiac rehabilitation (CR) after HTx were included. Exercise sessions were evaluated as ≥ 23 or < 23 sessions based on recursive partitioning. We included 140 patients who had undergone HTx (women: n = 41 (29%), age: 52 ± 12 years, body mass index: 27 ± 5 kg/m²). Mean follow-up was 4.1 ± 2.7 years, and 44 patients (31%) had a MACE: stroke (n = 1), percutaneous intervention (n = 5), heart failure (n = 6), myocardial infarction (n = 1), rejection (n = 16), or death (n = 15). CR was a significant predictor of MACE, with ≥ 23 sessions associated with a ∼ 60% reduction in MACE risk (hazard ratio [HR]: 0.42, 95% CI: 0.19-0.94, P = 0.035). This remained after adjusting for age, sex and history of diabetes (HR: 0.41, 95% CI: 0.18-0.94, P = 0.035) as well as body mass index and pre-HTx peak oxygen consumption (HR: 0.40, 95% CI: 0.18-0.92, P = 0.031).

CONCLUSIONS

After adjustment for covariates of age, sex, diabetes, body mass index, and pre-HTx peak oxygen consumption, CR attendance of ≥ 23 exercise sessions was predictive of lower MACE risk following HTx. In post-HTx patients, CR was associated with MACE prevention and should be viewed as a critical tool in post-HTx treatment strategies.

Predictors of exercise capacity following septal myectomy in patients with hypertrophic cardiomyopathy

AIMS

Patients with hypertrophic obstructive cardiomyopathy (HOCM) have impaired exercise capacity. The gold standard therapy for patients with HOCM is septal myectomy surgery; however, changes in maximum oxygen uptake (VO₂peak) following myectomy are variable, with VO₂peak decreasing in some patients. Therefore, we evaluated changes in VO₂peak following surgical myectomy to determine clinical predictors of those exhibiting decreased VO₂peak post-myectomy.

METHODS

HOCM patients (N = 295) who performed symptom limited cardiopulmonary exercise testing prior to and following surgical myectomy were included for analysis. The VO₂peak non-responder group (n = 128) was defined as <0% change in VO₂peak from pre- to post-myectomy. Step-wise regression models using demographics, clinical, and physiologic characteristics were created to determine predictors of hypertrophic cardiomyopathy patients in the VO₂peak non-responder group.

RESULTS

Independent predictors of the VO₂peak non-responder group included higher pre-myectomy VO₂peak (% predicted), older age, women, history of dyslipidemia, lack of cardiac rehabilitation enrollment, and lower body mass index (all p < 0.03). Forty-three (14.6%) patients reached the primary end-point of all-cause mortality during a median follow up of 11.25 years (interquartile range 6.94 to 16.40). After adjustment for age, sex, beta-blocker use, coronary artery disease history, and body mass index, the VO₂peak non-responder group had greater risk of death compared with the VO₂peak responder group (adjusted hazard ratio: 1.77, 95% confidence interval: 1.06-3.34, p = 0.01).

CONCLUSION

This large hypertrophic cardiomyopathy cohort demonstrated that demographic (i.e. female sex), lack of cardiac rehabilitation enrollment, and cardiovascular risk factors (i.e. history of dyslipidemia) are predictive of those patients that did not exhibit increases in VO₂peak following septal myectomy surgery.

Clinical and Rehabilitative Predictors of Peak Oxygen Uptake Following Cardiac Transplantation

The measurement of peak oxygen uptake (VO_2peak) is an important metric for evaluating cardiac transplantation (HTx) eligibility. However, it is unclear which factors (e.g., recipient demographics, clinical parameters, cardiac rehabilitation (CR) participation) influence VO_2peak following HTx. Consecutive HTx patients with cardiopulmonary exercise testing (CPET) between 2007–2016 were included. VO_2peak was measured from CPET standard protocol. Regression analyses determined predictors of the highest post-HTx VO_2peak (i.e., quartile 4: VO_2peak > 20.1 mL/kg/min). One hundred-forty HTx patients (women: n = 41 (29%), age: 52 ± 12 years, body mass index (BMI): 27 ± 5 kg/m²) were included. History of diabetes (Odds Ratio (OR): 0.17, 95% Confidence Interval (CI): 0.04–0.77, p = 0.021), history of dyslipidemia (OR: 0.42, 95% CI: 0.19–0.93, p = 0.032), BMI (OR: 0.90, 95% CI: 0.82–0.99, p = 0.022), hemoglobin (OR: 1.29, 95% CI: 1.04–1.61, p = 0.020), white blood cell count (OR: 0.81, 95% CI: 0.66–0.98, p = 0.033), CR exercise sessions (OR: 1.10, 95% CI: 1.04–1.15, p < 0.001), and pre-HTx VO_2peak (OR: 1.17, 95% CI: 1.07–1.29, p = 0.001) were significant predictors. Multivariate analysis showed CR exercise sessions (OR: 1.10, 95% CI: 1.03–1.16, p = 0.002), and pre-HTx VO_2peak (OR: 1.16, 95% CI: 1.04–1.30, p = 0.007) were independently predictive of higher post-HTx VO_2peak. Pre-HTx VO_2peak and CR exercise sessions are predictive of a greater VO_2peak following HTx. These data highlight the importance of CR exercise session attendance and pre-HTx fitness in predicting VO_2peak post-HTx.