Valvular heart disease in older adults: seeking an ounce of prevention
Year: 2016
Type: editorial
Abstract: This editorial refers to ‘Large-scale community echocardiographic screening reveals a major burden of undiagnosed valvular heart disease in older people: the OxVALVE Population Cohort Study’†, by J.L. d’Arcy et al., on page 3515. In 1848, Dr A. Whyte Barclay presented the results of his survey of the prevalence of valvular heart disease (VHD) from 419 autopsies occurring over a 2-year period at the St George’s Hospital in the UK.1 VHD was noted in 19%, with rheumatic disease and associated infectious endocarditis frequently noted, particularly among the younger patients. However, he also noted evidence of ‘atheromatous disease either on the valves themselves or in their immediate vicinity’ in 27%, with a markedly higher prevalence among older patients. Today, degenerative disease accounts for the majority of haemodynamically significant VHD in industrialized countries.2 In the USA, older adults ≥65 years of age are projected to account for 20% of the population by 2030.3 Moderate or severe VHD affects ∼2.5% of the US population, with a prevalence that increases steeply with age, affecting up to 12% of persons ≥75 years old.4 Significant VHD remains linked to worse prognosis, and is associated with a 35–75% higher risk of death compared with those without significant valvular disease.3 In this issue of the journal, baseline findings from the OxVALVE Population Cohort Study (OxVALVE-PCS) confirm the substantial burden of VHD in elderly persons.5 This prospective cohort study, designed to investigate the epidemiology of VHD in persons ≥65 years of age, recruited participants from five primary care medical centres in Oxfordshire, UK who then underwent echocardiography and clinical assessments. By combining the prevalence of diagnosed VHD (using National Health Service diagnostic codes) with new VHD detected by echocardiography, these investigators estimated a prevalence of moderate or severe VHD of 11.3% in their sample. From this analysis, it is unclear how many of these persons met clinical indications for valve intervention, given the importance both of patient symptoms and of the distinction between moderate and severe dysfunction in this therapeutic determination. However, findings from the Euro Heart Survey on VHD clearly demonstrate that a sizable proportion of elderly persons with significant VHD are candidates for intervention.2 The pool of older patients who are valve intervention candidates is expected to continue to grow with the expanding percutaneous options for VHD.6 Indeed, a recent meta-analysis and simulation study estimated that 290 000 persons >75 years of age in Europe and North America are candidates for transcatheter aortic valve replacement (TAVR) with 27 000 new candidates annually.7 Developing options for percutaneous mitral valve8 and tricuspid valve9 repair and further refinement of TAVR techniques will expand treatment options for severe VHD, and the number of elderly candidates for intervention. While these advances will demand refinement of patient selection for these procedures, they have—and will continue to—benefit our patients with severe VHD requiring therapy. However, OxVALVE-PCS also provides comprehensive estimates of the prevalence of lesser degrees of valvular dysfunction in older adults. They noted similar age-related increase in the prevalence of mild valve dysfunction, concordant with previous community-based samples for both regurgitant10–13 and stenotic14,15 VHD. The relatively high prevalence of mild VHD in these epidemiological studies emphasizes the progressive nature of VHD, whereby a subset of persons progress from a milder to a more severe degrees of valve dysfunction over time. The framework of VHD stages was adopted by the most recent American Heart Association/American College of Cardiology Valvular Heart Disease guidelines to emphasize the progressive nature of VHD.16 Stage A VHD defines an at-risk group based on morphological abnormalities of the valves, myocardium, and vessels. Stage B is characterized by progressive VHD based on the haemodynamic consequences of the lesion, while Stage C encompasses asymptomatic severe disease and Stage D symptomatic severe disease. While ageing is an important risk factor for progression through these stages,17 epidemiological and mechanistic studies also suggest an active pathological process. Higher blood pressure, worse renal function, and valvular calcification have been identified as risk factors for valvular regurgitation.10–13 Calcific stenotic VHD, and aortic sclerosis/stenosis in particular, has been associated with smoking, obesity, hypertension, and hypercholestaemia.14,18,19 Projections from OxVALVE-PCS, based on the growing elderly population, suggest that the number of elderly persons with moderate or severe VHD in the UK alone will more than double by 2056, from 1.5 to 3.3 million persons. While mechanical interventions to address significant VHD will surely continue to evolve and improve, these projections argue for the development of interventions to prevent the progression of VHD to haemodynamic significance in the elderly. One area in which such preventative intervention has been pursued is degenerative aortic valve disease, although results to date have been disappointing. The shared risk factors between calcific aortic valve disease and atherosclerosis suggested a shared pathophysiology, a hypothesis supported by histological studies.20,21 These findings suggested that degenerative aortic valve disease is an active—and therefore modifiable—process, and helped to motivate several randomized trials testing the use of statins in mild-to-moderate aortic stenosis for this purpose.22–24 One possible reason for the null results of these studies was the relatively advanced stage of disease by the time mild-to-moderate haemodynamic disturbance is present. Indeed, on a population level, epidemiological data suggest that improvement in cardiovascular risk factor control generally may be efficacious in delaying progression of aortic stenosis, and possibly lesions associated with valve calcification more broadly, although future prospective studies are need to test this hypothesis. Together, these findings highlight the need for prospective observational studies in diverse populations with careful participant and valve phenotyping, to define predictors and modifers of valve disease progression at earlier stages in the disease process, and to inform relevant treatment targets. The work for this manuscript was supported by NHLBI grant K08HL116792 (A.M.S.) and AHA grant 14CRP20380422 (A.M.S.). Conflict of interest: none declared.
Source: European Heart Journal
Authors: Amil M. Shah, Scott D. Solomon
Institution: Brigham and Women's Hospital
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2515087322