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Circulation. 2022;145:e895–e1032. DOI: 10.1161/CIR.0000000000001063 May 3, 2022 e917 CLINICAL STATEMENTS AND GUIDELINES the CardioMEMS device. All 3 studies estimated CardioMEMS implantation and monitoring increased survival and quality-adjusted life year (QALY) while increasing costs. Primarily based on differences regarding the expected magnitude of clinical benefit, 2 analyses5,7estimated the device provided high value while the third6 estimated intermediate value. These analyses had several important differences detailed in the evidence tables, including the model duration, QOL data, cost estimates, and assumptions regarding mortality. One analysis6 found the economic value of CardioMEMS implantation was highly dependent on its effect on mortality and duration of treatment benefit, both of which remain unclear. Cost-effectiveness studies incorporating data from GUIDE-HF4 have not been published. Additional data regarding clinical outcomes following CardioMEMS implantation will improve estimates of its economic value. 4.7 Exercise and Functional Capacity Testing Recommendations for Exercise and Functional Capacity Testing Referenced studies that support the recommendations are summarized in the Online Data Supplements. COR LOE Recommendations 1 C-LD 1. In patients with HF, assessment and documentation of NYHA functional classification are recommended to determine eligibility for treatments.1–3 1 C-LD 2. In selected ambulatory patients with HF, cardiopulmonary exercise testing (CPET) is recommended to determine appropriateness of advanced treatments (eg, LVAD, heart transplant).4–8 2a C-LD 3. In ambulatory patients with HF, performing a CPET or 6-minute walk test is reasonable to assess functional capacity.4,5,9–16 2a C-LD 4. In ambulatory patients with unexplained dyspnea, CPET is reasonable to evaluate the cause of dyspnea.17,18 Synopsis Functional impairment and exercise intolerance are common in HF. CPET and the 6-minute walk test are standardized, reliable, and reproducible tests to quantify functional capacity.19–22 The NYHA functional classification can be used to grade the severity of functional limitation based on patient report of symptoms experienced with activity1 and is used to define candidates for certain treatments. Recommendation-Specific Supportive Text 1. NYHA functional classification is an ordinal, categorical variable (I-IV) that is used to document functional limitation in patients with cardiac disease, including HF.1 In HF, NYHA functional class I includes patients with no limitations in physical activity resulting from their HF. NYHA class II includes patients who are comfortable at rest but have slight symptoms resulting from HF (dyspnea, fatigue, lightheadedness) with ordinary activity. NYHA class III includes patients who are comfortable at rest but have symptoms of HF with less than ordinary activity. NYHA class IV includes patients who are unable to carry out any physical activity without symptoms and have symptoms at rest. NYHA functional classification has been widely used in clinical practice, clinical trials, and clinical practice guidelines to determine candidacy for drug and device therapy. Limitations include its ability to be inconsistently assessed from 1 clinician to another, resulting in poor reproducibility.23 2. Many CPET variables have been associated with prognosis in patients with HF.4,5,12,14,16,24 Peak exercise oxygen consumption/oxygen uptake (VO2) is often used to risk stratify patients and make decisions about timing of advanced HF therapies, including heart transplantation and LVAD. In a landmark article,7 investigators divided patients referred for heart transplantation into groups based on their peak VO2.7 Patients with peak VO2 <14 mL/kg/min were listed for transplant, while those with higher peak VO2 values were deferred for being too well. Patients with peak VO2 >14 mL/kg/min who were deferred had 1- and 2-year survival of 94% and 84%, respectively, which was similar to survival after heart transplant. As such, the authors proposed peak VO2 ≤14 mL/ kg/min as a cutoff to distinguish patients who may derive survival benefit from heart transplant.7 Patients tolerating beta blockers may have improved survival with an equivalent VO2 compared with patients who do not tolerate beta blockers.25,26 For patients on beta blockers, a peak VO2 ≤12 mL/kg/min has been suggested as a more appropriate cutoff to consider cardiac transplant listing.8 3. Objective assessment of exercise capacity with CPET can be useful in the clinical management of patients with HF. Although CPET remains the gold standard measure of exercise capacity, limitations to more widespread use include need for special equipment and trained personnel, which leads to lack of availability at many hospitals and clinics. Furthermore, it is not well tolerated by some patients. The 6-minute walk test is an alternative way to measure exercise capacity that is widely available and well tolerated by patients. It entails walking for 6 minutes on a measured flat course, and patients are allowed to slow down or stop if needed. A systematic review of 14 studies found that the 6-minute walk test results correlated moderately with peak VO2 levels and were a reliable and valid indicator of functional capacity in patients with HF who did not walk >490 m.8 Distance walked in the 6-minute walk test has been associated with prognosis in HF Downloaded from http://ahajournals.org by on October 7, 2026