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Routine Echo Follow‐Up of the Patient after Transcatheter Aortic Valve Replacement

For patients with severe symptomatic aortic stenosis (AS) who are unacceptably highrisk surgical candidates, transcatheter aortic valve replacement (TAVR) has become a viable option. With nearly 9000 patients becoming eligible for TAVR annually in North America, the usage of TAVR and the number of patients requiring follow-up has been increasing. Transthoracic echocardiography (TTE) is a mainstay for follow-up of the postTAVR patient. This brief review discusses current routine echocardiography laboratory follow-up of patients having undergone the TAVR procedure. The two valves approved for TAVR are the Medtronic CoreValve and Edwards SAPIEN. The postimplant mean valve gradient (MVG) is approximately 10 mmHg for both valve types. CoreValve and SAPIEN MVGs have been followed over 4 and 5 years, respectively. Normally, there is no significant change in MVG from implant. An increase in MVG may indicate valvular dysfunction (Table I). In addition to MVG, the effective orifice area (EOA) should be followed. Transcatheter valves present a unique challenge in that flow acceleration occurs within the stents proximal to valve cuffs. Left ventricular outflow tract (LVOT) diameter measurements must be taken proximal to the stent (Fig. 1), otherwise the valve area may be overestimated. A decrease in the EOA by 0.3–0.4 cm or Doppler velocity index (DVI), defined as a ratio of proximal velocity in LVOT to that of the flow through the prosthetic valve, by 0.1–0.13 should prompt further hemodynamic evaluation. Patient–prosthesis mismatch (PPM) may result in an elevated MVG and should be suspected in the setting of an abnormal DVI. PPM is classified according to the calculated EOA (Table II). Although both para-prosthetic aortic valve regurgitation (PAVR) and transvalvular regurgitation may occur, the former is more significant, as PAVR is associated with increased shortand long-term mortality. Both annular diameter and prosthesis implantation depth have been found to be associated with moderate-to-severe PAVR. Semiquantitative measures of valve severity include color Doppler, interrogation below the valve stent in the LVOT for PAVR jets, and the coaptation point of the leaflets for a central regurgitation jet.