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Table of Contents
ORIGINAL ARTICLE
Year : 2018  |  Volume : 7  |  Issue : 2  |  Page : 98-102

Outcomes following transcatheter aortic valve replacement for aortic stenosis in patients of extreme age: Analysis from a rural population


Department of Internal Medicine, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, USA

Date of Web Publication22-May-2018

Correspondence Address:
Dr. Brent J Klinkhammer
University of Nebraska, 982055 Nebraska Medical Ctr, Omaha, Nebraska
USA
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/rcm.rcm_9_18

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  Abstract 


Introduction: Previous single- and multi-center studies done in predominantly metropolitan areas have shown transcatheter aortic valve replacement (TAVR) to be a safe and effective treatment modality for patients of advanced age with severe aortic stenosis. However, it is unknown whether similar patient cohorts from rural areas have similar outcomes or if these initial studies are not representative of the experience in more rural areas. Setting: This is a single-center health-care system in a predominantly rural area. Methods: A retrospective chart review case–control study of 339 consecutive patients who underwent a TAVR for severe aortic stenosis at Sanford Health in Fargo, ND, was performed to determine if advanced age (>80 years of age) at the time of TAVR affects short- and long-term outcomes. Results: Despite higher predicted baseline surgical risk,s predominantly rural patients of advanced age had no significant difference in overall survival at 1-month (93% vs. 97%, P = 0.228), 6-month (88% vs. 90%, P = 0.695), 1-year (79% vs. 82%, P = 0.611), or 2-year (63% vs. 60%, P = 0.731) post-TAVR versus younger patients from the same geographical area. Patients of advanced age also had no significant difference in periprocedural or echocardiographic outcomes out to 1-year post-TAVR. Conclusion: This study from a predominantly rural area gives evidence to suggest that there is no association between extreme age (>80 years of age) and decreased overall survival. In addition, high baseline Society of Thoracic Surgeons and European System for Cardiac Operative Risk Evaluation predicted risk was not suggestive of worse outcomes in patients of advanced age. This study gives reassurance of the safety of TAVR in patients of advanced age in rural areas.

Keywords: Age, outcomes, survival, transcatheter aortic valve replacement


How to cite this article:
Klinkhammer BJ. Outcomes following transcatheter aortic valve replacement for aortic stenosis in patients of extreme age: Analysis from a rural population. Res Cardiovasc Med 2018;7:98-102

How to cite this URL:
Klinkhammer BJ. Outcomes following transcatheter aortic valve replacement for aortic stenosis in patients of extreme age: Analysis from a rural population. Res Cardiovasc Med [serial online] 2018 [cited 2019 Nov 22];7:98-102. Available from: http://www.rcvmonline.com/text.asp?2018/7/2/98/232980




  Introduction Top


Previous studies have shown transcatheter aortic valve replacement (TAVR) to be a safe and effective treatment modality for patients of advanced age with severe aortic stenosis.[1],[2],[3] However, the studies that have directly compared older cohorts of patients to younger patient groups have been limited to either single large metropolitan area health-care system or multicenter analyses of mostly urban centers. To the best of our knowledge, there have been no studies involving TAVR for severe aortic stenosis in elderly patients from the more rural areas of America.

Studies conducted in other area of cardiology gives reason to believe that the outcomes seen in an urban center and metropolitan-based studies may not be representative of the experience of rural centers. For example, in a study published by Baldwin et al., patients presenting to rural hospital for acute myocardial infarction experienced an increase in 30-day mortality compared to urban centers.[4] Likewise, in a study from Canada, urban patients were more likely to have office-based physician visits in the 1st year after a heart failure diagnosis and had lower rates of hospitalization than rural patients.[5]

There also have been documented differences in the management of aortic stenosis between urban and rural America. In a study by Vavalle et al., patients in the most rural parts of North Carolina had the highest rates of hospitalizations for aortic stenosis and the lowest rates of valvular surgery.[6] Approximately 19.3% of the US population (60 million people) lives in a rural area and the composition of rural America today is disproportionally elderly. These facts underscored the importance of the study of the rural elderly population in today's changing health-care landscape.[7] This study aims to describe the outcomes of TAVR for severe aortic stenosis in patients of extreme age from a predominantly rural area.


  Methods Top


A hospital-based, single-institution case–control study was conducted using data from one upper Midwestern integrated health system. We performed a retrospective chart review of 339 consecutive patients who underwent a TAVR at Sanford Health in Fargo, ND, from August 10, 2012, to November 15, 2016, for severe aortic stenosis, defined as an aortic valve area <1 cm2. The last date of data acquisition was January 4, 2017. The entire cohort was divided into two groups where the patients aged 80 years or older at the time of TAVR were placed in one “extreme age” cohort, while all other patients were designated as controls. Primary outcomes were overall survival at 1-month, 6-month, 1-year, and 2-year post-TAVR. Secondary outcomes were procedural complications, post-TAVR permanent pacemaker implantation, major adverse cardiovascular and cerebrovascular events defined as death from any cause, myocardial infarction, rehospitalization, or stroke, cardiovascular mortality, myocardial infarction, stroke/transient ischemic attack, heart failure exacerbation, or rehospitalization for any reason in defined time periods. Pre- and postprocedural echocardiographic data were also compared. The clinical outcomes were assessed in accordance with the standardized endpoint definitions for TAVR of the Valve Academic Research Consortium-2.[8] Heart failure exacerbation was defined as a gradual or rapid change in heart failure signs and symptoms resulting in a need for a change in therapy or hospitalization.

Informed consent was not required for inclusion in our retrospective study due to the nature of the study and the absence of any direct interventions. This study protocol received dual Institutional Review Board (IRB) approval from the University of North Dakota IRB and from the Sanford Health IRB. The Fisher's exact test was performed to determine the statistical significance of categorical data, and t-test or Wilcoxon two-sample test was used to determine the statistical significance continuous variables. All P values were two-sided, and P < 0.05 was considered statistically significant.


  Results Top


A total of 195 of the 339 patients met study criteria for inclusion in advanced age cohort. Baseline characteristics for both groups are given in [Table 1]. Statistically significant differences were noted in age, body mass index, Society of Thoracic Surgeons (STS) risk score, European System for Cardiac Operative Risk Evaluation (EuroSCORE), preprocedural diabetes mellitus, and prior coronary artery revascularization procedures. There were a high amount of significant comorbidities in both groups including an 88% prevalence of hypertension in the entire cohort. Mean age of the entire cohort was 79.2 years of age. Procedural characteristics for both groups are given in [Table 2]. There were no statistical differences in the specific type of valve used; however, there was small but statistically significant increase in the utilization of the transaortic approach in the younger cohort. Pre- and postprocedural echocardiographic data are given in [Table 3]. A difference in baseline ejection was found which was not sustained at 1-year post-TAVR. Finally, the primary and secondary outcome data for this study are given in [Table 4]. Overall survival for the entire study cohort was 80.2% at 1 year and 61.4% at 2 years.
Table 1: Baseline characteristics

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Table 2: Procedural characteristics

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Table 3: Echocardiographic characteristics

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Table 4: Primary and secondary outcomes

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  Discussion Top


This study adds to the previously published data and gives evidence to suggest that patients of extreme age (>80 years of age) at the time of TAVR do not have asignificantly increased mortality out to 2-year post-TAVR. To the best of our knowledge, this study is the first of its kind and demonstrates this important clinical finding in a patient cohort from a predominantly rural area. The findings of this study help to establish the clinical acceptability of TAVR in the most elderly population, especially those in rural America who may be underrepresented in previous studies.

Much like the study published by Orvin et al., this study did find some important differences in baseline characteristics between the older and younger patient cohorts.[2] The “extreme age” cohort had a significantly higher predicted surgical risk, noted in the cohort's STS score and EuroSCORE risk. This finding underlines the limited utility of these scores in TAVR, particularity in older cohorts. The previous work by Beohar et al. found that STS risk scores overestimated 30-day and inhospital mortality, which is consistent with the finding of this study.[9] These surgical risk scores should likely not be used for patient selection in the patient over the age of 80.

Correspondingly, like the study done by Orvin et al., this study also found that older patients chosen for TAVR have some differences in baseline characteristics as well. In our study, this is notably in the significantly lower rates of diabetes mellitus, prior coronary artery bypass graft surgery, reduced ejection fraction at baseline, and lower average body mass index. This finding was largely consistent with the previous study although our larger study had less statistically significant differences overall.[2] This suggests that the predictors of a poor outcomes that have been derived from larger cohorts may not be useful in older cohorts.[10]

The physical location of this single-center study and its finding which are consistent with data from urban multicenter clinical studies imply many other important corollaries as well. First, this study helps to establish that the limited access to advanced cardiac care does not imply worse outcomes after TAVR. This finding is particularly important given the overall physician shortage in rural states such as North Dakota and the forecast for future shortages in cardiologists both nationwide and in rural areas.[11],[12],[13] Second, this study implies that geriatric patients can be safety monitored following TAVR in areas affected the most by these shortages. Third, this study infers the safety of TAVR performed at a moderate-sized center as compared to large tertiary care centers.

Finally, our data indicate that unlike other common cardiac conditions, the treatment of aortic stenosis in high surgical risk patients does not suffer any urban to rural differences in overall outcomes. We believe that it is increasingly important that the potential impact of geography and practice setting be continually evaluated to establish the widespread efficacy and safety of cardiovascular care, especially as it relates to cardiac device implantation. The current mechanism for cardiovascular research does not adequately address the specific challenges of rural health care nor do they sufficiently represent the roughly one-fifth of Americans who live in these areas. Pragmatic clinical studies like the one we present here could serve as a model for the efficient study of rural patients undergoing similar procedures in the future.

This study does have some limitations including its retrospective design, single-center experience, and inequalities in the length of post-TAVR follow-up. Like all retrospective analyses, the potential for confounding factors which were not identified and addressed in the study's baseline patient characteristics does exist. This study was designed to capture as many pertinent baseline characteristics as possible to effectively isolate the independent variable as much as possible. Patients in both groups were reasonably well-matched overall; however, we did find a significant difference in TAVR approach, in that patients in the younger cohort had a higher rate of transapical approach utilization. The impact of this on our result is unclear, in that previous studies that have compared the outcomes of transapical to transfemoral TAVR have yielded conflicting results.[14],[15]


  Conclusion Top


In this study from a predominantly rural area, no association between extreme age (>80 years of age) and decrease overall survival was found. In addition, high baseline STS and EuroSCORE predicted risk was not suggestive of worse outcomes in patients of advanced age. This study gives reassurance of the safety of TAVR in patients of advanced age and in rural areas with ongoing physician and cardiology access difficulties.

Acknowledgment

The investigator would like to thank Thomas Haldis, DO, and Cornelius Dyke, MD, for their help in getting this project started and Ronda Bolgrean, RN, for her help with data acquisition.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Kayatta MO, Thourani VH, Jensen HA, Condado JC, Sarin EL, Kilgo PD, et al. Outcomes for transcatheter aortic valve replacement in nonagenarians. Ann Thorac Surg 2015;100:1261-7.  Back to cited text no. 1
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2.
Orvin K, Assali A, Vaknin-Assa H, Levi A, Greenberg G, Codner P, et al. Efficacy and safety of transcatheter aortic valve implantation in aortic stenosis patients with extreme age. J Invasive Cardiol 2015;27:475-80.  Back to cited text no. 2
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3.
Smith CR, Leon MB, Mack MJ, Miller DC, Moses JW, Svensson LG, et al. Transcatheter versus surgical aortic-valve replacement in high-risk patients. N Engl J Med 2011;364:2187-98.  Back to cited text no. 3
[PUBMED]    
4.
Baldwin LM, MacLehose RF, Hart LG, Beaver SK, Every N, Chan L, et al. Quality of care for acute myocardial infarction in rural and urban US hospitals. J Rural Health 2004;20:99-108.  Back to cited text no. 4
    
5.
Gamble JM, Eurich DT, Ezekowitz JA, Kaul P, Quan H, McAlister FA, et al. Patterns of care and outcomes differ for urban versus rural patients with newly diagnosed heart failure, even in a universal healthcare system. Circ Heart Fail 2011;4:317-23.  Back to cited text no. 5
    
6.
Vavalle JP, Phillips HR, Holleran SA, Wang A, O'Connor CM, Smith PK, et al. Analysis of geographic variations in the diagnosis and treatment of patients with aortic stenosis in North Carolina. Am J Cardiol 2014;113:1874-8.  Back to cited text no. 6
    
7.
New Census Data Show Differences between Urban and Rural Populations. US Census Bureau; 8 December, 2016. Available from: https://www.census.gov/newsroom/press-releases/2016/cb16-210.html. [Last accessed on 2017 June 27].  Back to cited text no. 7
    
8.
Kappetein AP, Head SJ, Généreux P, Piazza N, van Mieghem NM, Blackstone EH, et al. Updated standardized endpoint definitions for transcatheter aortic valve implantation: The valve academic research consortium-2 consensus document. J Thorac Cardiovasc Surg 2013;145:6-23.  Back to cited text no. 8
    
9.
Beohar N, Whisenant B, Kirtane AJ, Leon MB, Tuzcu EM, Makkar R, et al. The relative performance characteristics of the logistic European system for cardiac operative risk evaluation score and the society of thoracic surgeons score in the placement of aortic transcatheter valves trial. J Thorac Cardiovasc Surg 2014;148:2830-70.  Back to cited text no. 9
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10.
Arnold SV, Afilalo J, Spertus JA, Tang Y, Baron SJ, Jones PG, et al. Prediction of poor outcome after transcatheter aortic valve replacement. J Am Coll Cardiol 2016;68:1868-77.  Back to cited text no. 10
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11.
Rodgers GP, Conti JB, Feinstein JA, Griffin BP, Kennett JD, Shah S, et al. ACC 2009 survey results and recommendations: Addressing the cardiology workforce crisis a report of the ACC board of trustees workforce task force. J Am Coll Cardiol 2009;54:1195-208.  Back to cited text no. 11
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12.
Gruca TS, Pyo TH, Nelson GC. Providing cardiology care in rural areas through visiting consultant clinics. J Am Heart Assoc 2016;5. pii: e002909.  Back to cited text no. 12
    
13.
Foruth Biennial Report: Health Issues for the State of North Dakota. UND School of Medicine and Health Sciences Advisory Council; 2017. Available from: http://www.med.und.edu/biennial-report/_files/docs/fourth-biennial-report.pdf. [Last accessed on 2017 July 02].  Back to cited text no. 13
    
14.
Schymik G, Würth A, Bramlage P, Herbinger T, Heimeshoff M, Pilz L, et al. Long-term results of transapical versus transfemoral TAVI in a real world population of 1000 patients with severe symptomatic aortic stenosis. Circ Cardiovasc Interv 2015;8. pii: e000761.  Back to cited text no. 14
    
15.
Biancari F, Rosato S, D'Errigo P, Ranucci M, Onorati F, Barbanti M, et al. Immediate and intermediate outcome after transapical versus transfemoral transcatheter aortic valve replacement. Am J Cardiol 2016;117:245-51.  Back to cited text no. 15
    



 
 
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  [Table 1], [Table 2], [Table 3], [Table 4]



 

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