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

Abstract

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.

Effects of Mavacamten on Measures of Cardiopulmonary Exercise Testing Beyond Peak Oxygen Consumption

“…In both treatment arms, 45% of patients performed CPET using an exercise bicycle and 55% using a treadmill (Figure 1). Baseline CPET parameter values were similar for both treatment groups (Table 1) and consistent with values reported previously for patients with HCM . Heart rate and systolic blood pressure at rest and at peak exercise are summarized in eTable 2 in Supplement 1.…”

Myosin modulators: emerging approaches for the treatment of cardiomyopathies and heart failure

“…A longer-term objective for mavacamten or aficamten beyond alleviating obstruction is the potential for disease modification. Even with complete surgical relief of obstruction, peak VO2 fails to improve in approximately 40% of patients ( 63 ), which supports the findings that diastolic dysfunction and factors other than obstruction are the primary determinants of exercise capacity in HCM ( 64 , 65 ). Mavacamten decreases diastolic stiffness and improves lusitropy in human engineered heart tissue ( 66 ).…”

Current therapies for hypertrophic cardiomyopathy: a systematic review and meta‐analysis of the literature

“… 14 , 15 However, the results from recent studies support the current recommendations, which suggest that the promotion of supervised physical exercise results in an improved quality of life for the patients with this condition. 60 Moreover, in a recent meta‐analysis from our group including 11 672 HCM patients, the mean VO2max was 22.3 ± 1.1 mL/kg/min (6.4 ± 1.1 MET), 61 which stands right below the classical threshold of functionality of 7 MET. Considering the pooled mean benefit of exercise on functional capacity observed in this study (4.33 mL/kg/min, 1.1 MET), physical training emerges as a non‐invasive and non‐pharmacological alternative that might potentially help HCM patients achieving a functional state without affecting other echocardiographic parameters such as LVEF%.…”