SHAPE Test for Preoperative Risk Stratification

Preoperative functional capacity is a central component of perioperative risk assessment in older adults undergoing moderate- to high-risk surgery. Reduced cardiopulmonary reserve is associated with increased postoperative morbidity, prolonged recovery, and major adverse cardiovascular events, yet functional capacity in routine practice is often estimated using subjective measures such as self-reported activity tolerance, MET estimates, and questionnaire-based assessment. These tools are practical but may misclassify physiologic fitness, particularly in older adults who report acceptable activity levels despite diminished aerobic reserve.

Objective cardiopulmonary exercise testing can provide more precise assessment, but widespread use is limited by the complexity and burden of conventional testing. The SHAPE-HF cardiopulmonary testing system is an FDA-approved simplified submaximal exercise testing platform intended to provide objective assessment of aerobic fitness in a manner that may be more feasible for routine use in a preoperative clinic.

Conventional cardiopulmonary exercise testing can provide objective assessment of aerobic capacity, but broad implementation is often limited by time, workflow, equipment, and patient burden. The SHAPE-HF cardiopulmonary testing system is an FDA-approved simplified submaximal cardiopulmonary exercise testing platform designed to generate objective physiologic measures of aerobic fitness using abbreviated exercise testing. This approach may offer a more practical method for assessing functional capacity in a high-volume preoperative clinic while reducing the burden associated with traditional maximal exercise testing.

This study is a prospective, single-site, non-randomized investigation evaluating the use of the SHAPE-HF cardiopulmonary testing system in adults older than 60 years who are undergoing preoperative evaluation before moderate- to high-risk surgery. The study population includes patients with a Revised Cardiac Risk Index (RCRI) score less than 4 and self-reported functional capacity greater than 4 METs who otherwise meet protocol-defined eligibility criteria. This population was selected because many such patients would typically be considered to have acceptable functional status by standard preoperative screening, yet some may still have unrecognized limitations in aerobic capacity and increased perioperative risk.

The study has been modified over time to support progressively broader scientific aims. It was initially conducted as a technical proof-of-concept study enrolling 42 participants to evaluate implementation of simplified submaximal cardiopulmonary exercise testing in the preoperative setting. The protocol was subsequently modified to a feasibility study with a planned enrollment of 101 participants to evaluate recruitment, workflow integration, and practical use of the SHAPE-HF system in an older surgical population. The study has now been further expanded to a total planned enrollment of 371 participants in order to better evaluate perioperative complications and the relationship between submaximal cardiopulmonary exercise testing performance and postoperative outcomes, and to provide adequate statistical power to identify associations with major adverse perioperative events.

Participants complete a single in-person study visit of approximately 35 minutes during the preoperative period. During this visit, conventional preoperative functional assessments are obtained, including subjective MET assessment and Duke Activity Status Index evaluation, and participants undergo SHAPE-HF submaximal cardiopulmonary exercise testing. A follow-up telephone contact is performed approximately 24 hours after testing to assess for adverse events related to the study procedure. Participants then undergo postoperative follow-up through medical record review for 30 days after surgery.

The primary objectives of the current study are to evaluate the feasibility and operational performance of using the SHAPE-HF cardiopulmonary testing system in a preoperative clinic for older adults undergoing moderate- to high-risk surgery and to assess the relationship between SHAPE-HF-derived performance measures and clinically relevant postoperative outcomes. Study aims include comparison of SHAPE-HF results with conventional measures of functional capacity, including subjective MET assessment and Duke Activity Status Index scores. The study also evaluates whether SHAPE-HF performance variables are associated with short-term postoperative morbidity, as measured by the Postoperative Morbidity Survey, and with major postoperative complications within 30 days of surgery.

Postoperative outcomes of interest include major adverse cardiovascular and other clinically significant perioperative events, including myocardial infarction, stroke, atrial fibrillation, congestive heart failure, pneumonia, hospital readmission, and death. By expanding from proof-of-concept and feasibility phases to a larger powered cohort, the study is intended to determine whether abbreviated submaximal cardiopulmonary exercise testing can improve identification of older surgical patients at elevated perioperative risk beyond conventional subjective assessment alone.

This investigation is not designed to alter the participant's planned surgical treatment or routine perioperative care. Rather, it evaluates whether an abbreviated, objective, and scalable assessment of aerobic fitness can be integrated into preoperative evaluation and whether the resulting physiologic measures may improve perioperative risk stratification in older adults presenting for moderate- to high-risk surgery.

Inclusion criteria

• Aged >60 years
• Scheduled for pre-surgical evaluation for moderate to high-risk surgical procedure.
• RCRI <2 based on screening of preoperative co-morbidities.
• Provision of signed and dated informed consent form

Exclusion criteria

• Age <60 years old
• Subjective METS <4
• Inability to give independent informed consent
• Revised Cardiac Risk Index (RCRI) >2
• Neurological impairment with motor limitations
• Mental impairment leading to inability to cooperate
• Recent NSTEMI or STEMI type myocardial infarction (within 6 months)
• Angina (stable or unstable, within 6 months)
• Uncorrected severe valvular heart disease (severe aortic, tricuspid, or mitral stenosis)
• Recent exacerbation of congestive heart failure (requiring hospitalization, within 6 months)
• Acute pulmonary embolism or deep vein thrombosis (within past 6 months)
• Uncontrolled pulmonary edema
• Uncontrolled symptomatic arrhythmias
• Active endocarditis
• Acute myocarditis or pericarditis
• Active wheezing or home oxygen use
• Recent exacerbation of chronic obstructive pulmonary disease or asthma or pneumonia (requiring hospitalization, within 6 months)
• Inability to perform components of the SHAPE test (severe hip flexion limitation, severe osteoarthritis of knee or hip, limb immobilization, ambulation with a walker, can or crutches, baseline balance irregularities
• Diagnosis of vertigo
• Known allergic reactions to components of the SHAPE medical system apparatus disposable mouthpiece.
• Active enrollment in an interventional clinical trial within the enrollment period of the study.