CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 5, September/October 2022 268 AFRICA Patient selection • Patients must have symptomatic severe aortic stenosis (AS). • The patient must be evaluated by an MDT. Indications for TAVI • TAVI is indicated in patients where there are concerns regarding the technical difficulties of sAVR. Possible procedurespecific impediments are: – Porcelain aorta – Severe atherosclerosis of the aorta – Hostile chest (irradiation or previous sternotomy) – Potential damage to existing coronary artery grafts in the setting of a previous CABG. • Frailty – Patients deemed to be too frail for sAVR should be considered for TAVI. This is often a subjective clinical assessment and the use of validated frailty scores can be helpful to obtain a more objective measure of the extent of a patient’s frailty. There are numerous scores available, but a practically useful assessment tool is the essential frailty toolset (EFT) score, which correlates with one-year mortality5 (see Table 1). • Major organ compromise of two or more organ systems. Patients must be evaluated carefully for co-morbidities and the estimated survival related to these should be longer than one year. The severity of these co-morbidities should not be such that it limits the expected clinical improvement after TAVI (see Contra-indication below). Examples of significant co-morbidities include: – Cardiac: severe left ventricular (LV) or right ventricular (RV) dysfunction, severe pulmonary hypertension – Respiratory dysfunction: forced exhaled volume in 1 sec (FEV1) or diffusing capacity for CO2 (DLCO2) < 50% predicted – Neurological: dementia, Alzheimer’s disease, Parkinson’s disease – Gastrointestinal tract: ulcerative colitis, Chron’s disease – Hepatic: cirrhosis – Oncological concerns (but with expected survival of at least one year). • TAVI should be considered as the primary procedure for all patients deemed to be at high6 or intermediate risk for sAVR.7,8 The primary assessment of surgical risk resides with the MDT rather than formal quantitative risk scores such as the log EuroSCORE or the Society of Thoracic Surgeons (STS) risk score. Risk scores are however useful as an addition to the clinical assessment to assist the MDT to determine the best intervention for a patient. An STS risk score of > 4 generally indicates at least intermediate risk for adverse periprocedural outcomes with sAVR. • TAVI should be considered in low-risk patients (STS score < 4) older than 75 years of age, if a transfemoral access option is feasible.9-11 As there is still considerable uncertainty regarding the long-term durability of transcatheter valves, sAVR remains the first option in younger patients at low surgical risk, particularly in the setting of bicuspid or rheumatic aortic valve disease. • The factors considered to choose the optimal aortic valve intervention are summarised in Table 2.3 Table 2. Factors considered to choose the optimal aortic valve intervention. (Adapted from Vahanian et al. Eur J Cardio-Thorac Surg 2021; 60: 727–800.) Variables Favours TAVI Favours sAVR Clinical characteristics Lower surgical risk + Higher surgical risk + Presence of severe co-morbidity (not reflected by risk score) + Younger age + Older age + Previous cardiac surgery + Frailty + Restricted mobility that may affect rehabilitation after the procedure + Suspicion of endocarditis + Anatomical and technical aspects Favourable access for transfemoral TAVI + Femoral access challenging or impossible + Sequelae of chest radiation + Porcelain aorta + Expected patient-prosthesis mismatch + Severe chest deformity or scoliosis + Short distance between coronary ostia and aortic valve annulus + Size of aortic valve annulus out of range for TAVI + Aortic root morphology unfavourable for TAVI + Valve morphology unfavourable for TAVI (bicuspid, degree of calcification and calcification pattern) + Presence of thrombi in aorta or left ventricle + Cardiac conditions in addition to AS that require consideration for concomitant intervention Severe CAD requiring revascularisation by CABG + Severe primary mitral valve disease + Severe tricuspid valve disease + Aneurysm of the ascending aorta or significant aortic root dilatation + Septal hypertrophy requiring myomectomy + TAVI, transcatheter aortic valve implantation; sAVR, surgical aortic valve replacement; CAD, coronary artery disease; CAGB, coronary artery bypass graft. Table 1. EFT score for frailty. (Adapted from Afilalo et al. J Am Coll Cardiol 2017; 70(6): 689–700.) EFT score for frailty Points Five chair rises < 15 seconds 0 Five chair rises > 15 seconds 1 Unable to complete 2 No cognitive impairment 0 Cognitive impairment 1 Haemoglobin > 13 g/dl male and > 12 g/dl female 0 Haemoglobin < 13 g/dl male and < 12 g/dl female 1 Serum albumin > 3.5 g/dl 0 Serum albumin < 3.5 g/dl 1 EFT score 1-year mortality TAVI, % sAVR, % 0–1 6 3 2 15 7 3 28 16 4 30 38 5 65 50 EFT, essential frailty toolset; TAVI, transcatheter aortic valve implantation; sAVR, surgical aortic valve replacement.
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