A team from Trinity College Dublin describes the protocol involved in the assessment of elderly patients for transcatheter aortic valve implant (TAVI) and the role of the cardiology CNS
Aortic stenosis (AS) is the most prevalent valvular heart disease and the third most common cardiovascular condition, after coronary artery disease and hypertension. 1 Severe AS has been documented in 2-7% of patients greater than 65 years of age with incidence higher in men than in women.2 Transcatheter aortic valve implant (TAVI) was introduced for patients with severe AS in 2002,3 as the shift from surgery for highly symptomatic elderly patients, to less invasive procedures reached the field of heart valves.
This new innovative cardiology procedure is rapidly evolving to treat inoperable AS patients and has been introduced into some hospitals in Ireland. This article describes the protocol and algorithms involved in the assessment of older patients for TAVI and the role of the clinical nurse specialist (CNS) in this.
The number of Irish people over the age of 65 is expected to increase by almost 50% between 2011 and 2026.4 As a result, the burden of cardiac disease among older people who are highly symptomatic will continue to rise. Older age is an independent risk factor for higher mortality and morbidity in cardiac populations.
Aortic valve replacement (AVR) in otherwise fit octogenarians can be performed with a relatively low mortality and morbidity rate. Elderly patients who have a heavy burden of co-morbid diseases, which are likely to lead to complications and an increased risk of adverse outcomes, are not offered this option. However, AS is progressive and will not improve without treatment.
Untreated AS can lead to pulmonary hypertension, arrhythmias, endocarditis, myocardial infarction, congestive heart failure and sudden death.5 Elderly AS patients who do not have AVR intervention, have a >12 fold increase in mortality risk.6 TAVI is recommended under current ESC 2012 Guidelines for these patients, who have been deemed unsuitable for conventional open heart surgery due to multiple comorbidities.
The first TAVI case performed in an Irish healthcare setting took place in December 2008, with 93 TAVI procedures performed in St James’s Hospital, Dublin since then.
|Table 1: Recommendations for the use of transcatheter aortic valve implantation|
|TAVI should only be undertaken with a multidisciplinary ‘heart team’ including cardiologists and cardiac surgeons and other specialists if necessary||I||C|
|TAVI should only be performed in hospitals with cardiac surgery on-site||I||C|
|TAVI is indicated in patients with severe symptomatic AS who are not suitable for AVR as assessed by a ‘heart team’ and who are likely to gain improvement in their quality of life and to have a life expectancy of more than one year after consideration of their comorbidities||I||B|
|TAVI should be considered in high-risk patients with severe symptomatic AS who may still be suitable for surgery, but in whom TAVI is favoured by a ‘heart team’ based on the individual risk profile and anatomic suitability||IIa||B|
Prior to TAVI, patients undergo thorough assessment and preparation to determine their suitability for the procedure and to ensure an informed decision is made by the patient and family. One of the first roles of the cardiology CNS is to partake in patient education to assist the patient and their family make an informed decision about their care.
Clinical decision making should be a shared process between the patient and the multidisciplinary team. As this is a relatively new treatment option in Ireland the CNS should have a good level of knowledge regarding severe AS, TAVI risks, type of procedures, benefits, perioperative and post procedural complications to sufficiently inform the patient.
There are a number of inclusion and exclusion criteria for TAVI patients.
TAVI exclusion criteria
TAVI exclusion criteria
The work-up assessment for TAVI is performed by the multidisciplinary team; which currently includes two interventional cardiologists, a cardiothoracic surgeon, a cardiology Imaging consultant and a cardiology CNS.
|Figure 1: Management of severe aortic stenosis ESC/EACTS Guidelines 2012|
|AS = aortic stenosis AVR = aortic valve replacement BSA = body surface area
LVEF = left ventricular ejection fraction Med Rx = medical therapy
TAVI = transcatheter aortic valve implantation.
b Surgery should be considered (IIaC) if one of the following is present: peak velocity >5.5m/s; severe valve calcification + peak velocity progression ≥0.3 m/s/year. Surgery may be considered (IIbC) if one of the following is present: markedly elevated natriuretic peptide levels; mean gradient increase with exercise >20 mmHg; excessive LV hypertrophy.
c The decision should be made according to individual clinical characteristics and anatomy
Patients undergo a comprehensive work-up prior to TAVI with a full comprehensive health history, comprehensive physical examination; full blood screen including FBC, U&E, coagulation and liver profile; MRSA screen; ECG; transesophageal ECHO; CT coronary angiogram; transthoracic ECHO; coronary and peripheral angiogram; aortogram; pulmonary function test and carotid doppler.
The CNS currently plays a major part in collating the patient history, performing a full physical examination, assessing their quality of life and level of frailty. Centres in Ireland and across Europe have dedicated advanced nurse practitioners (ANPs) for patient screening, assessment and ANP clinic evaluation. Clinical history taking is the first step in assessing AS severity. Severity is indicated by progressive symptoms such as decreased exercise tolerance or shortness of breath on exertion,7 which will need to be assessed.8 Heart failure, angina and syncope are late manifestations of this challenging disease process and may also be present.
Additional symptoms associated with underlying co morbidities, which are also important to note, need also to be assessed. Tailoring individual patient assessment, planning and intervention can be enhanced by ensuring the CNS/ ANP has a good understanding of TAVI clinical outcomes. Once the full work-up is completed and patients are deemed suitable and agree to TAVI, the procedure is performed using the technique most appropriate for the patient. There are multiple access routes whereby a transcatheter valve can be deployed: transfemoral, transapical, trans-subclavian and transaortic.
Direct transaortic insertion by way of a mini-thoracotomy is the latest method over transapical approach. Percutaneous TAVI is mainly performed using a retrograde transfemoral route under local anaesthetic. In cases where there is evidence of diseased, tortuous, calcified femoral and iliac arteries the trans-subclavian, transapical, transaortic routes are assessed for suitability. All three of these methods of insertion require general anaesthetic. There are two valves currently on the market; CoreValve and Edwards Sapien. The CoreValve is a nitinol stent with porcine pericardium leaflets. The Edwards Sapien stent has a balloon expandable cobalt chromium frame with bovine pericardial tissue.
TAVI procedure requires a dedicated expert cardiac catheterisation laboratory team including nurses, doctors and cardiac technicians and in addition, coronary care unit (CCU) nurses for post procedural care.
TAVI patient outcomes
The first multicentre prospective randomised control trial of TAVI patients, the Placement of AoRtic TraNscathetER Valves (PARTNER) trial, took place in 2010. The PARTNER trial compared TAVI patient outcomes to either conventional AVR or standard medical therapy, both for severe symptomatic elderly patients. TAVI was identified as reducing mortality, when compared to surgical patients; 30-day mortality: 3.4% versus 6.5% respectively and one-year mortality 24.2% versus 26.8% respectively.9 After one year, there was no significant difference between TAVI and AVR in relation to cardiovascular death 14.3% versus 13%.10
Following this, the German Aortic Valve Registry (GARY Trial, 2011) was designed to review and govern current outcomes and to evaluate safety and effectiveness of TAVI.11 The GARY trial did not observe a significant difference in mortality between TAVI patients and CABG but it did observe a reduction in cerebrovascular complications. Similarly of the 93 patients undergoing TAVI in this Irish centre none of the patients had a complicated cerebrovascular accident, which is consistent with the experience of the GARY Registry.
Throughout the literature , the periprocedural stroke rate ranged between 0%-8%.8,12,13 It is important to note although AVR stroke rate occurred in 3% of octogenarians,14 TAVI patients have multiple co-morbidities including atherosclerosis which predisposes these patients to stroke. TAVI procedural success currently in the literature is achieved in 86-100% of cases using the transfemoral approach.12,15,16 Presently procedural mortality rates account for <10% for transfemoral implant and <14% for transapical approach.11 The Irish procedural mortality rate of 2% was in line with international findings.
Improvement in HRQOL is recognised as a therapeutic benefit specifically for elderly valve surgery patients, particularly when increased survival may be neither likely nor sought by the patient.17 There is a demonstrable lack of research focusing on HRQOL and no consensus on the definition and measurement of QOL despite Macduff highlighting the need to assess health care outcomes using HRQOL in addition to mortality and morbidity.18 The PARTNER trial, Cohort A, highlighted a remarkable improvement in HRQOL within one month of TAVI when compared to AVR; however, similar benefits occurred over the one year follow-up in both groups.
Sinéad Teehan is a cardiology clinical nurse specialist at St James’s Hospital, Dublin; Gabrielle McKee is associate professor of biological sciences, School of Nursing and Midwifery, TCD; and Dr Orla Dempsey is quantitative healthcare lead at the Centre for Practice and Healthcare Innovation, TCD
|Continuing Education - Cardiology - Management of severe aortic stenosis|