Transcatheter aortic valve implantation: Periprocedural and postprocedural management

INTRODUCTION — Aortic valve replacement (AVR) is the mainstay of treatment of symptomatic severe aortic stenosis (AS). The role of transcatheter aortic valve implantation (TAVI; also known as transcatheter aortic valve replacement or TAVR) as an alternative to surgical aortic valve replacement (SAVR) is established, and in 2019, the number of TAVIs exceeded SAVRs in the US for the first time [1]. A multidisciplinary team approach is recommended in approaching patients with symptomatic AS. (See "Choice of intervention for severe calcific aortic stenosis".)

This topic will review periprocedural management of TAVI [2]. Post-TAVI antithrombotic therapy, indications for AVR, choice of aortic valve intervention (TAVI versus SAVR), medical therapy for symptomatic AS, and percutaneous aortic valvuloplasty are discussed separately. (See "Indications for valve replacement for high gradient aortic stenosis in adults" and "Transcatheter aortic valve implantation: Antithrombotic therapy" and "Choice of intervention for severe calcific aortic stenosis" and "Choice of prosthetic heart valve for surgical aortic or mitral valve replacement" and "Estimating the risk of valvular procedures" and "Medical management of symptomatic aortic stenosis" and "Percutaneous balloon aortic valvotomy for native aortic stenosis in adults".)

PREPROCEDURAL CONSIDERATIONS

Indications, contraindications, and choice of therapy — Candidates for TAVI should be fully evaluated for symptoms, aortic stenosis severity, and comorbid pathologies. The indication for valve intervention (surgical aortic valve replacement [SAVR] or TAVI), and choice of therapy based upon potential risks (including absolute and relative contraindications for either procedure) and benefits of treatment options (including any TAVI access issues), should be discussed at a meeting of a multidisciplinary heart team. This should comprise interventional and noninterventional cardiologists (including imaging specialists) and cardiac surgeons and may include other clinicians with relevant expertise, including critical care, pulmonary specialists, and anesthesiologists [3]. Potential risk factors such as depressed left ventricular ejection fraction, coronary artery disease, kidney disease, prior stroke, and respiratory disorders should be considered. Potential TAVI access issues and likely delivery approach should be discussed since the access route may impact the risk-benefit analysis of treatment options. These issues are discussed separately. (See "Indications for valve replacement for high gradient aortic stenosis in adults" and "Choice of intervention for severe calcific aortic stenosis".)

Preprocedural management — Preprocedural management includes selection of the optimal clinical setting for the procedure, and preprocedural assessment.

The choice of the optimal clinical setting for the procedure is based upon regional clinical expertise and experience, as well as patient access. An inverse relationship between hospital TAVI procedural volume and mortality has been observed [4]. In an analysis of data from the Transcatheter Valve Therapy Registry on 96,256 transfemoral TAVI procedures during 2015 to 2017 at 554 hospitals, adjusted 30-day mortality was higher and more variable in hospitals in the lowest volume quartile (mean annualized volume of 27 procedures; mortality 3.19 percent; 95% CI 2.78-3.67) than at hospitals in the highest volume quartile (mean annualized volume of 143 procedures, mortality 2.66 percent, 95% CI 2.48-2.85; odds ratio [OR] 1.21, 95% CI 1.03-1.41). An analysis of 8644 nontransfemoral TAVI cases at 486 sites also revealed an inverse relationship between volume of TAVI procedures and mortality with adjusted 30-day mortality of 10.13 percent in the lowest-volume quartile and 6.40 percent in the highest volume quartile (OR 1.65, 95% CI 1.20-2.27).

Preprocedural testing should include:

●Routine blood tests (including complete blood count, prothrombin time, activated partial thromboplastin time, electrolytes, blood urea nitrogen, and serum creatinine).

●An electrocardiogram.

●Resting echocardiography (transthoracic and, in some cases, transesophageal).

If low gradient AS is suspected, low-dose dobutamine stress echocardiography and/or computed tomography may also be indicated, as discussed separately. (See "Clinical manifestations and diagnosis of low gradient severe aortic stenosis", section on 'Additional evaluation based upon type of low gradient AS'.)

●Coronary angiography. This will depend upon local practice, as patients without prior coronary disease and without angina may be evaluated by coronary computed tomographic angiography as a screening procedure rather than invasive angiography, the latter being undertaken immediately prior to the TAVI procedure.

●Comprehensive computed tomography to assess aortic annulus geometry and peripheral access.

Preprocedural imaging is discussed in detail separately. (See "Imaging for transcatheter aortic valve implantation", section on 'Preprocedural assessment' and "Clinical manifestations and diagnosis of low gradient severe aortic stenosis", section on 'Diagnosis and evaluation'.)

PROCEDURAL CONSIDERATIONS — TAVI procedural management includes administration of antimicrobial prophylaxis, monitoring, anticoagulation with heparin, temporary pacemaker lead placement (use varies), access (transfemoral or an alternative approach), anesthesia technique selection and care, hemodynamic management, and prevention and treatment of complications. (See "Transcatheter aortic valve implantation: Complications".)

Procedural antibiotic prophylaxis — Routine antibiotic prophylaxis is recommended for all patients undergoing TAVI prior to surgical incision or vascular access to reduce the risk of wound infection and endocarditis using the same protocols used for cardiac surgery (table 1) [3]. (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults", section on 'Cardiac surgery'.)

Monitoring, pacing, and anticoagulation — Patients undergoing TAVI generally receive at least one large-bore intravenous line, warming to avoid hypothermia if general anesthesia is used, and monitoring by arterial line [3]. A pulmonary artery catheter is seldom used during the procedure. Transesophageal echocardiography is commonly performed when general anesthesia is used.

A temporary pacing lead is commonly placed but use varies widely, and an increasingly common practice is to pace with the preshaped left ventricular TAVI wire.

Intravenous unfractionated heparin (weight-adjusted with target activated clotting time between 250 and 300 seconds) is administered after placement of standard sheaths and prior to placement of the large sheath.

Access routes — The transfemoral arterial approach is the most common and most favored method of TAVI delivery, and nearly all (>95 percent) cases can be performed via this route. When transfemoral access is not feasible, choice of alternative access route is based upon patient-specific anatomy and risk factors, operator and institutional practice and experience, and the type of valve delivery system used. Alternative (nontransfemoral) approaches include subclavian/axillary, transaortic, transapical, transcaval, and transcarotid access.

Preprocedural assessment for TAVI includes assessment of the iliofemoral system and aorta, generally by multidetector computed tomography with optional invasive angiography to detect contraindications to vascular (transfemoral, subclavian, or aortic) access such as plaques with mobile thrombi in the ascending aorta or arch, inadequate vessel size, extensive calcification, or tortuosity. For the transapical approach, severe pulmonary disease, severe left ventricular disease, or other conditions may render the left ventricular apex inaccessible. Extensive ascending aortic calcification is an infrequent contraindication to the direct aortic approach as a soft spot for catheter entry can usually be found.

When transfemoral access for TAVI is feasible, it is preferred to alternative access since there is greater experience and superior reported outcomes with transfemoral access. Furthermore, the benefits of TAVI over surgery in the PARTNER 2 trial and United States Pivotal Trial were greatest in the transfemoral cohorts. However, it is unclear how much of the excess mortality seen in patients undergoing alternative access TAVI is caused by the alternative access procedure per se and how much is caused by excess risk associated with the burden of peripheral vascular disease, mandating the need for alternative access. (See "Choice of intervention for severe calcific aortic stenosis", section on 'By access site'.)

Observational studies have found that patients undergoing transcarotid TAVI have lower transfusion rates and shorter lengths of stay compared with patients undergoing transapical or transaortic access [5,6]. A systematic review of observational studies comparing outcomes with transcarotid access versus outcomes with other access types found that 30-day mortality was lower with transcarotid access versus transaortic access (2.6 versus 12.1 percent; relative risk [RR] 2.93, 95% CI 1.15-7.58) [7].

Transfemoral approach — The percutaneous retrograde femoral arterial approach via the aortic arch and through the diseased valve is the most common approach to TAVI delivery. The use of the transfemoral approach is favored and indeed feasible in >95 percent of patients in some registries, reflecting smaller sheath sizes in newer generation devices. It is now rare for a transfemoral approach to be excluded due to access vessel size since the two major commercially available valve delivery systems are now 14 to 16 F equivalent. Vessel size of less than 5 mm together with circumferential calcium would represent a contraindication, as well as extreme vessel tortuosity. Peripheral artery imaging (computed tomography and, in some cases, invasive angiography) is performed to determine feasibility and risk of a transfemoral approach, as discussed separately. (See "Imaging for transcatheter aortic valve implantation", section on 'Determining eligibility for peripheral vascular access'.)

For patients with calcific iliofemoral vessels, transfemoral access may be facilitated by peripheral lithotripsy [8].

Several types of stent-valve devices with various designs have been successfully implanted using the retrograde femoral approach. The most widely used types are balloon-expandable valves (SAPIEN 3 and SAPIEN 3 Ultra, which have replaced the Cribier-Edwards, SAPIEN, and SAPIEN XT valves) and self-expanding valves (eg, Evolut PRO/PRO-PLUS, ACURATE neo, and Portico) [9]. The SAPIEN 3 and SAPIEN 3 Ultra valves can also be delivered via the transapical or direct aortic approach as described below. The Evolut PRO/PRO-PLUS can also been delivered in a retrograde fashion from the subclavian/axillary artery [10], the carotid artery, and via direct aortic access via either ministernotomy or right anterior thoracotomy [11].

Smaller delivery devices have resulted in an increasing rate of femoral delivery (eg, from approximately 50 percent to approximately 95 percent), as well as lower incidence of vascular complications, with standard use of a percutaneous vascular closure device and a shorter hospital stay. Protamine is routinely administered for heparin reversal after arterial sheath removal. An observational study of 873 patients undergoing TAVI, of whom 677 received protamine, found that protamine administration was associated with reduced rates of life-threatening and major bleeding complications with no increase in the risk of stroke [12].

Alternative approaches — For patients who are not candidates for the transfemoral approach due to unfavorable iliofemoral artery characteristics, the most common current access alternatives are trans-subclavian access, two transthoracic approaches (transaortic retrograde and the transapical antegrade), and the transcarotid approach. The choice between these alternatives will depend upon which valve type is being selected as well as operator and hospital experience.

●Trans-subclavian/axillary – The subclavian retrograde approach is performed by either surgical cut-down to the subclavian artery or percutaneous axillary artery access for insertion of the transcatheter heart valve (THV) delivery system.

●Transaortic – The transaortic retrograde surgical approach is performed by direct insertion of the THV delivery system into the ascending aorta (eg, aortotomy) using a sheath placed into the aorta via a small median sternotomy or lateral thoracotomy at the second intercostal space.

●Transapical – The transapical antegrade approach involves direct left ventricular apical puncture for insertion of the THV delivery system and antegrade aortic valve implantation via a small anterolateral thoracotomy without cardiopulmonary bypass or sternotomy. This approach is particularly suited to patients with severe peripheral artery disease and heavily calcified ascending aorta and arch (porcelain aorta) who have an increased risk of stroke and other embolic events using other approaches.

●Transcaval – The transcaval approach involves passage of an electrified guidewire from the inferior vena cava toward a snare in the abdominal aorta [13]. The THV introducer sheath is advanced from the femoral vein into the abdominal aorta for retrograde TAVI.

●Transcarotid – The transcarotid retrograde approach is performed by surgical cut-down of the common carotid artery for insertion of the THV delivery system. Neurologic monitoring (eg, electroencephalogram, transcranial Doppler, cerebral oximetry) is used during the procedure.

Anesthetic management — Selection of anesthesia technique varies depending upon the TAVI access route and center and operator practice:

●Transfemoral or transcaval TAVI may be performed with either local anesthesia with moderate (conscious) sedation or general anesthesia.

●Patients requiring a subclavian/axillary approach commonly receive general anesthesia, although there is increasing use of local anesthesia with moderate sedation.

●Patients requiring a transaortic, transapical, or transcarotid approach generally receive general anesthesia.

As center and operator experience has grown, there has been a move toward performing TAVI with a less invasive approach [14]. While practice varies considerably, this approach encompasses performing the procedure under conscious sedation with local anesthesia, without transesophageal echocardiography, and with selective use of temporary pacing (including using the preshaped left ventricular wire for this purpose). Some operators have moved away from having any anesthesia support and most have dispensed with central venous access. Anesthetic management (including discussion of studies comparing anesthetic approaches) is discussed further separately. (See "Anesthesia for percutaneous cardiac valve interventions", section on 'Transcatheter aortic valve implantation'.)

Role of cerebral embolic protection — Cerebral embolic protection (CEP) systems have been developed to capture or deflect debris released during TAVI to reduce the risk of stroke. However, a clinical benefit from CEP systems has not been established.

A meta-analysis of seven randomized trials included 2171 patients in the CEP group (using one of four different systems) and 1860 in the control group [15]. Stroke rates were similar in the groups with and without CEP (odds ratio [OR] 0.84, 95% CI 0.60-1.17) and rates of disabling stroke were also similar (OR 0.57, 95% CI 0.24-1.36). Mortality rates were also similar (OR 1.04, 95% CI 0.50-2.18).

In the largest included trial (PROTECTED TAVR), 3000 patients were randomly assigned to CEP (n = 1501) and control (n = 1499) groups [16]. Stroke within 72 hours after TAVI or before discharge occurred at similar rates in CEP and control groups (2.3 versus 2.9 percent; -0.6 percentage points, 95% CI -1.7 to 0.5). The rate of disabling stroke was lower in the CEP group (0.5 versus 1.3 percent; -0.8 percentage points, 95% CI -1.5 to -0.1). On the basis of this data, the number of patients needed to treat to prevent one disabling stroke would be 125. One patient (0.1 percent) had a major bleeding event at the CEP access site.

Despite these results, clinicians recognize that debris is captured in a significant proportion of embolic protection filters in cases where it is used and thus may reduce the risk of disabling stroke. On this basis, operators continue to believe that it has a role in selected patients. However, opinions vary as to when it is most appropriate to select CEP, ranging between younger (albeit lower risk) patients where stroke is to be avoided at all cost, and higher-risk patients (eg, bicuspid disease or degenerating xenografts) where stroke might be more commonly expected as a complication. The BHF PROTECT-TAVI Trial (British Heart Foundation Randomised Clinical Trial of Cerebral Embolic Protection in Transcatheter Aortic Valve Implantation) is currently randomly assigning over 7000 patients to TAVI either with or without CEP in all UK TAVI centers. This will provide further data on this question, and a prespecified meta-analysis with the recently reported PROTECTED TAVR Trial should provide a definitive answer.

The risk of stroke after TAVI is discussed further separately. (See "Transcatheter aortic valve implantation: Complications", section on 'Stroke and subclinical brain injury'.)

Implantation procedure — Prior to the implantation, the available imaging of the aortic root (including preprocedural computed tomography angiography and echocardiography) should be obtained and displayed for the operators.

The implantation procedure consists of five phases:

●The first is to obtain vascular access for delivery of the valve. (See 'Access routes' above.)

●Second, the operators use the available aortic root imaging to establish a clear coplanar view of the aortic annulus. The standard coplanar view has all three aortic cusps equidistant and aligned. However, for self-expanding valves, there is increasing use of the "cusp overlap" view, which isolates the noncoronary cusp (right and left coronary cusps overlap) and elongates the left ventricular outflow tract. This information is used to guide transcatheter heart valve (THV) size and placement. (See "Imaging for transcatheter aortic valve implantation".)

●In selected cases, a balloon aortic valvuloplasty is performed prior to delivery of the THV [17]. Indications for predilation include the presence of one or more of the following: bicuspid aortic valve, very heavy valve calcification, difficulty crossing the valve, or extremely high transvalvular gradient.

●Next, the THV is delivered. The range of implantation techniques and methods varies widely as valve design and methods of expansion mandate different delivery approaches, although some principles are universal:

•The valve should be correctly positioned in the aortic annulus, extending below the plane of the annulus by between 2 and 5 mm, depending upon the valve design. It should be positioned to avoid paravalvular leaks and coronary occlusion.

•Its position should be checked with fluoroscopy and possibly echocardiography as well.

Any paravalvular leak that is present should be quantified with a combination of echocardiography, angiography, and pressure measurement to calculate the aortic regurgitation index. The aortic regurgitation index is

in which DBP is aortic diastolic blood pressure, LVEDP is left ventricular end-diastolic pressure, and SBP is systolic blood pressure.

●If there is an indication for repositioning (such as suboptimal depth or angulation of the initial implantation, paravalvular regurgitation, new or worsened atrioventricular block, or coronary artery impingement), and the valve is of a recapturable and repositionable type, then repositioning should be considered. Finally, the need for a postdeployment valvuloplasty should be considered to improve frame expansion if this is a concern.

Hemodynamic management — All procedures require early identification and treatment of volume depletion, low cardiac output, and greater than moderate pulmonary hypertension. Measures to avoid prolonged hypotension include maintenance of mean arterial pressure of >75 mmHg prior to initiation of rapid ventricular pacing, with cautious use of intravenous vasopressor (metaraminol, norepinephrine, epinephrine, or phenylephrine) therapy as needed while avoiding hypertension. Patients with low cardiac output undergoing TAVI may require an intravenous inotrope (eg, metaraminol, norepinephrine), but mechanical circulatory support is very rarely needed. (See "Short-term mechanical circulatory assist devices" and "Anesthesia for percutaneous cardiac valve interventions", section on 'Transcatheter aortic valve implantation'.)

Complications — Management of complications of TAVI is discussed separately. (See "Transcatheter aortic valve implantation: Complications".)

POSTPROCEDURAL CARE

General considerations — Care post-TAVI includes clinical and echocardiographic follow-up of bioprosthetic valve function, including assessment of the transvalvular gradient and surveillance for complications. Patients typically undergo routine clinical evaluation including echocardiography prior to discharge and at one-month follow-up, at 6 to 12 months, and then annually. More frequent follow-up is required for complications such as paravalvular regurgitation and associated conditions such as heart failure. Complications of TAVI are discussed separately. (See "Transcatheter aortic valve implantation: Complications".)

Most patients undergoing TAVI have one or more comorbid conditions that require ongoing follow-up and treatment, particularly hypertension (observed in approximately 90 percent of patients [18]) and other cardiovascular disease (including coronary artery disease). As only limited observational data are available on antihypertensive therapy in this setting [18,19], hypertension post-TAVI is managed according to standard recommendations. (See "Overview of hypertension in adults" and "Choice of drug therapy in primary (essential) hypertension".)

Endocarditis prophylaxis — All patients with prosthetic valves, including those who have undergone TAVI, are considered among those at highest risk for endocarditis. Patient education should include instruction regarding the risk of infective endocarditis, the importance of optimal dental hygiene and regular dental care, the need for endocarditis prophylaxis at the time of relevant procedures, and the importance of seeking medical attention, including blood cultures promptly if symptoms of endocarditis develop. Antimicrobial prophylaxis is recommended in the setting of relevant procedures likely to result in bacteremia with a microorganism that is known to be a cause of endocarditis (eg, dental procedures that involve manipulation of gingival tissue or the periapical region of the teeth, or perforation of the oral mucosa, such as tooth extraction and routine dental cleaning). Relevant procedures and recommended regimens are discussed in detail separately. (See "Prevention of endocarditis: Antibiotic prophylaxis and other measures".)

Antithrombotic therapy — Post-TAVI antithrombotic therapy is discussed separately. (See "Transcatheter aortic valve implantation: Antithrombotic therapy".)

RAS antagonist — Observational studies have identified lower mortality rates in patients who have undergone TAVI who are treated with a renin-angiotensin system (RAS) inhibitor (angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker) compared with patients who have not received such therapy [20-24]. Most patients who have undergone TAVI have hypertension, for which a RAS inhibitor is a treatment of choice for most patients (see "Choice of drug therapy in primary (essential) hypertension"). A randomized trial is underway to study the effects of an angiotensin inhibitor on clinical outcomes and ventricular remodeling after TAVI [25].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Cardiac valve disease" and "Society guideline links: Transcatheter aortic valve implantation".)

SUMMARY AND RECOMMENDATIONS

●Preprocedural evaluation – Candidates for transcatheter aortic valve implantation (TAVI) should be fully evaluated for symptoms, aortic stenosis severity, and comorbid pathologies. The indication for valve intervention and choice of therapy based upon potential benefits and risks of treatment options (including any TAVI access issues) should be discussed at a multidisciplinary heart team meeting. (See 'Preprocedural considerations' above and "Indications for valve replacement for high gradient aortic stenosis in adults" and "Choice of intervention for severe calcific aortic stenosis".)

●Procedural considerations – TAVI procedural management includes administration of antimicrobial prophylaxis (table 1), monitoring, anticoagulation with heparin, temporary pacemaker lead placement (use varies), access (transfemoral or an alternative approach), anesthesia technique selection and management, hemodynamic management, and management of complications. (See 'Procedural considerations' above and "Transcatheter aortic valve implantation: Complications".)

●Access routes – The transfemoral arterial approach is the most common and most favored method of TAVI delivery, and nearly all (>95 percent) cases can be performed via this route. For patients who are not candidates for the transfemoral approach due to unfavorable iliofemoral artery characteristics, the most common current alternatives are the subclavian/axillary approach, two transthoracic approaches (transaortic and transapical), the transcaval approach, and the transcarotid approach. (See 'Access routes' above.)

●Implantation procedure – The transcatheter valve implantation procedure involves obtaining vascular access, establishing a clear coplanar view of the aortic annulus, balloon aortic valvuloplasty (in selected cases), delivery of the transcatheter heart valve (THV), repositioning (if indicated and feasible), and post-deployment valvuloplasty (if indicated to improve frame expansion). (See 'Implantation procedure' above.)

●Postprocedural care – Post-TAVI care includes clinical and echocardiographic follow-up, endocarditis prophylaxis, and antithrombotic therapy. (See 'Postprocedural care' above and "Prevention of endocarditis: Antibiotic prophylaxis and other measures" and "Transcatheter aortic valve implantation: Antithrombotic therapy".)

●Endocarditis prophylaxis – All patients with prosthetic valves, including those who have undergone TAVI, are considered among those at highest risk for endocarditis, and therefore prophylaxis for bacterial endocarditis is suggested for relevant high-risk procedures. (See 'Endocarditis prophylaxis' above and "Prevention of endocarditis: Antibiotic prophylaxis and other measures".)