Functional Status as a Measure of Quality of Life After Surgical and Transcatheter Aortic Valve Replacement

Editor's Note: Commentary based on Kim DH, Afilalo J, Shi SM, et al. Evaluation of changes in functional status in the year after aortic valve replacement. JAMA Intern Med 2019.

Rationale for Study:
Procedural outcomes following aortic valve surgery, either surgical (SAVR) or transcatheter (TAVR), have improved over time. However, functional status, which is a patient centered outcome, has largely been assessed using disease specific indices (NYHA classification, KCCQ questionnaire) rather than generic assessments of quality of life. The goal of this study was to characterize change in functional status over 12 months following SAVR or TAVR to provide information on clinical meaningful trajectories with the aim of improving shared decision making prior to these procedural interventions.

Funding: This study was conducted with the support of a KL2/Harvard Catalyst Medical Research Investigator Training award and additional support from Harvard Catalyst/The Harvard Clinical and Translational Science Center, National Institutes of Health.

Study Methods

Study Design: Planned sub-study of the prospective Frailty Assessment Before Cardiac Surgery and Transcatheter Interventions Study. 446 older patients undergoing SAVR or TAVR between February 1, 2014 and March 31, 2016 at a single medical center were screened, and 246 were enrolled. Preoperative assessment included review of cardiac and noncardiac medical conditions, NYHA classification for HF, echocardiographic data, STS risk score, depressive symptoms, MMSE, gait speed, chair stands. Medical history, functional performance and nutritional status, the comprehensive geriatric assessment-based frailty index (CGA-FI, range 0-1 higher values indicate higher frailty) was calculated.

Inclusion Criteria:
Adults >70 years undergoing SAVR or TAVR for severe aortic stenosis (AS)

Exclusion Criteria:

  • Emergent surgery or surgery involving another valve or aorta
  • Clinically unstable patients (decompensated heart failure, hemodynamic instability or active myocardial ischemia)
  • Severe neuropsychiatric impairment
  • Non-English speaking

Exposure: TAVR or SAVR

Primary outcome(s): At 1, 3, 6, 9, and 12 months patients were assessed by phone for their self-reported ability to perform 22 daily activities and physical tasks, classified as either cognitively or physically demanding.

Secondary outcomes: A composite variable of major postoperative complications was defined as any occurrence The Society of Thoracic Surgeons-Predicted Risk of Mortality major morbidity or mortality events or the Valve Academic Research Consortium–2 early safety end point. Delirium assessments, using the Confusion Assessment Method algorithm, in the hospital were added to the study protocol eight months after the cohort began.

Statistical Analysis:

Group-based trajectory modeling was used to identify clusters of patients who followed similar functional status trajectories over 12 months after TAVR or SAVR. The functional status composite scores during follow up were modeled using censored normal distribution.

Preoperative characteristics including CGA-FI levels were compared among patients with different trajectories using the Kruskal-Wallis test for continuous variables and Fisher exact test for categorical variables.

The impact of major complications and delirium on different trajectories was also assessed.

Missing data for preoperative variables (largest was gait speed [n = 35]) and functional status scores was imputed using a multivariate imputation by chained equations based on available information on preoperative characteristics, procedure type, complications, functional status, and mortality.

Results:

Of the 446 screened patients, 200 were excluded for not meeting selection criteria (N = 96), declined participation (N = 39) or were not approached by the team (N = 60). 143 individuals who underwent TAVR (mean age 84 +/- 5.9 years, 52% women) and 103 who underwent SAVR (mean age 78 +/- 5 years, 48% women) were enrolled in the study. Five patients were excluded who died before 1 month follow up.

Five trajectories were identified based on functional status at baseline and during follow-up (Table): excellent (excellent baseline to improvement), good (high baseline to full recovery), fair (moderate baseline to minimal decline), poor (low baseline to moderate decline) and very poor (low baseline to large decline). 12 month mortality was high in the group with very poor trajectory (9 of 13 [69.2%]) compared with poor (6 of 24 [25.0%]), fair (7 of 71 [9.9%]), good (2 of 70 [2.9%]), or excellent (2 of 57 [3.5%]) trajectories.

Trajectory

Overall (N=246)

TAVR

SAVR

Excellent

58 (24%)

20 (14%)

38 (37%)

Good

72 (30%)

33 (23%)

39 (38%)

Fair

74 (31%)

54 (38%)

20 (19%)

Poor

24 (10%)

21 (15%)

3 (3%)

Very poor

13 (5%)

12 (8%)

1 (1%)

Preoperative frailty level was associated with lower probability of functional improvement and greater probability of functional decline. After TAVR, patients with CGA-FI level of 0.20 or lower (N = 6) had excellent or good (100%) trajectories, whereas most patients with CGA-FI level of 0.51 (N = 15) or higher had poor or very poor (69%) trajectories. After SAVR, most patients with CGA-FI level of 0.20 or lower (N=39) had excellent or good (96%) trajectories compared with a fair trajectory (71%) in those with CGA-FI levels of 0.41 to 0.50 (N = 5).

Postoperative delirium and major complications were associated with functional decline after TAVR or lack of improvement after SAVR.

Limitations of study:

Trajectory modeling in this study was based on 22 activities of daily living assessed from patient reported abilities rather than objective functional assessments. These data are from a single center participating in a larger multi-center prospective study. Most patients who underwent TAVR had previous-generation heart valves and these data should be used cautiously when applied to more contemporary, lower risk populations. Furthermore, this is not a randomized study and should not be used to guide procedure selection.

Conclusion:

Patients with higher preprocedural function followed more favorable trajectories and recovered their preoperative function within 3 months, whereas those with lower function had poor or very poor trajectories and remained persistently impaired.

After TAVR, functional ability in about a quarter of the patients declined, while a third improved and the remainder maintained their preoperative level of function. In patients undergoing SAVR, who were relatively healthier and had higher baseline function, functional status improved in three quarters, remained stable in approximately one-fifth, and declined in very few. Except for those with very poor trajectory, disease-specific benefit (NYHA class 1 or 2 heart failure) was achieved in almost half of the patients with poor trajectory and most of those with fair, good, and excellent trajectories.

This study contributes to the current literature by demonstrating significant change in functional status over time after TAVR or SAVR, rather than dichotomizing end points of function or disease specific decline. The preoperative frailty assessment using CGA-FI or other techniques may offer patients and physicians important information beyond the STS risk score about their expected trajectory following SAVR or TAVR. However, this information cannot be used to guide procedural selection. The study provides beneficial information to both patients and cardiologists, to encourage the incorporation of frailty metrics in preprocedural shared decision making and post procedure expectation management.

Clinical Topics: Cardiac Surgery, Geriatric Cardiology, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Acute Heart Failure, Interventions and Imaging, Interventions and Structural Heart Disease, Echocardiography/Ultrasound

Keywords: Aortic Valve, Patient Selection, Geriatric Assessment, Geriatrics, Prospective Studies, Activities of Daily Living, Research Personnel, Transcatheter Aortic Valve Replacement, Follow-Up Studies, Aortic Valve Stenosis, Quality of Life, Echocardiography, Delirium, Postoperative Complications, Myocardial Ischemia, Heart Failure, Hemodynamics, Algorithms, Decision Making, National Institutes of Health (U.S.)


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