Background
Transcatheter aortic valve replacement (TAVR) is increasingly being performed in cardiac catheterization laboratories using transthoracic echocardiography (TTE) to guide valve deployment. The risk of paravalvular regurgitation (PVR) remains a concern.
Methods
We retrospectively reviewed 454 consecutive patients (mean age, 82 ± 8; 58% male) who underwent transfemoral TAVR at Emory Healthcare from 2007 to 2014. Two hundred thirty-four patients underwent TAVR in the cardiac catheterization laboratory with TTE guidance (TTE-TAVR; mean Society of Thoracic Surgeons score, 10%), while 220 patients underwent the procedure in the hybrid operating room with transesophageal echocardiography (TEE) guidance (TEE-TAVR; mean Society of Thoracic Surgeons score, 11%). All patients received an Edwards valve (SAPIEN 55%, SAPIEN-XT 45%). Clinical and procedural characteristics, echocardiographic parameters, and incidence of PVR were compared.
Results
The incidence of at least mild PVR at discharge was comparable between TTE-TAVR and TEE-TAVR (33% vs 38%, respectively; P = .326) and did not differ when stratified by valve type. However, in the TTE-TAVR group, there was a higher incidence of second valve implantation (7% vs 2%; P = .026) and postdilation (38% vs 17%; P < .001) during the procedure. Although not independently associated with PVR at discharge (odds ratio = 1.12; 95% CI, 0.69–1.79), TTE-TAVR was associated with PVR-related events: the combined outcome of mild PVR at discharge, intraprocedural postdilation, and second valve insertion (odds ratio = 1.58; 95% CI, 1.01–2.46). There were no significant differences in PVR at 30 days, 6 months, and 1 year between the two groups.
Conclusions
TTE-TAVR in a high-risk group of patients was associated with increased incidence of intraprocedure PVR-related events, although it was not associated with higher rates of PVR at follow-up. Multicenter randomized trials are required to confirm the cost-effectiveness and safety of TTE-TAVR.
Highlights
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Minimalist transthoracic echocardiography (TTE)–guided transcatheter aortic valve replacement (TAVR) is increasingly performed in cardiac catheterization laboratories.
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Patients undergoing TTE-TAVR were more likely to receive balloon postdilation and second valve placement.
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Paravalvular regurgitation at discharge was not increased with TTE-guided TAVR.
Transcatheter aortic valve replacement (TAVR) is now a well-established therapy for high and intermediate surgical risk patients with severe aortic stenosis. Cost remains a major hurdle to the expansion of TAVR as many patients require intubation, general anesthesia, invasive monitoring, and postoperative intensive care unit (ICU) monitoring. Institutions have explored ways to reduce the invasiveness and cost of TAVR in select patients by a “minimalist approach” using the transfemoral (TF) route in the cardiac catheterization laboratory, conscious sedation, and transthoracic (TTE)—rather than transesophageal (TEE)—guided valve deployment in conjunction with fluoroscopy. This minimalist approach (TTE-TAVR) has been shown to be less costly and associated with outcomes comparable to the standard approach that uses TEE guidance for valve deployment. However, the risk of paravalvular regurgitation (PVR) remains a concern, as even mild PVR has been shown to adversely impact outcomes. The use of TEE for valve deployment is considered optimal given its superior spatial resolution and image quality compared with the TTE-guidance on which TTE-TAVR depends. Whether TTE-guided valve deployment is associated with a higher incidence of PVR is unclear. We determined and compared the incidence and severity of PVR in patients who received balloon-expandable valves by TTE-TAVR and TEE-TAVR via the TF approach.
Methods
Study Design
We retrospectively reviewed 454 consecutive patients who underwent TF TAVR at Emory Healthcare from 2007 to 2014. Patients received a balloon-expandable transcatheter valve (SAPIEN or SAPIEN-XT, Edwards Lifesciences, Irvine, CA) via the TF approach either in the hybrid operating room (TEE-TAVR) or the cardiac catheterization laboratory (TTE-TAVR). Patients who underwent non-TF approaches (i.e., transapical, transaortic, transcaval, etc.) were not included in the analysis. Of note, as of May 2012, patients mostly underwent TTE-TAVR and multidetector computed tomography (CT) sizing with three-dimensional (3D) reconstruction of the aortic annulus, unless contraindicated. Early in our experience, preprocedural TEE (with 3D reconstruction with available) and periprocedural balloon sizing during initial valvuloplasty were used for annular sizing. More recently, when CT sizing was either unavailable or contraindicated, preprocedural 3D TEE and periprocedural balloon sizing was still primarily used. Periprocedural TEE or TTE provided adjunctive confirmatory sizing information. Clinical and procedural characteristics were collected, and reports of periprocedural and follow-up echocardiograms were reviewed. The study was approved by the Institutional Review Board at Emory University (Atlanta, GA).
Minimalist TTE and Standard TEE Approach
The TTE-TAVR was performed as described elsewhere. Patient selection for TTE-TAVR was not formally protocolized but relied on a heart team approach involving cardiothoracic surgery, anesthesiology, and the cardiovascular interventionalist. In brief, TTE-TAVR was performed under local anesthesia, conscious sedation, and fully percutaneous access site entry and closure. Procedures were done in a standard cardiac catheterization laboratory. A catheterization laboratory nurse, under the direction of the operating physician, administered sedation with fentanyl and midazolam. Preclosure was performed with vascular closure devices (Perclose, Abbott Vascular, Abbott Park, IL). Wire and catheter techniques were used to align the delivery system through the center of the stenotic valve and allow for coaxial deployment. Under TTE guidance, the guidewire for valve delivery was first positioned in the left ventricular apex, free from the mitral apparatus. Next, the echogenic ends of the transcatheter valve were identified in the parasternal long-axis view, allowing for coaxial alignment of the valve within the left ventricular outflow tract ( Figure 1 ). If the valve was not coaxial, feedback was given to the operator to manipulate the delivery catheter (often with a counterclockwise rotation of the delivery catheter) and guidewire to improve coaxial alignment. Once the valve was aligned with the tips of the native aortic valve, the valve was deployed with rapid ventricular pacing. Immediate assessment of the implanted valve was performed by TTE. Patients who underwent the procedure early in the experience were transferred from the catheterization laboratory to an ICU. Subsequent patients were sent to a regular telemetry floor unless a complication occurred.
TEE-TAVR was performed as described elsewhere, in a hybrid operating room with endotracheal intubation, bladder catheterization, pulmonary artery catheter hemodynamic monitoring, general anesthesia, and percutaneous femoral artery access. Patients were then transferred from the operating room to an ICU for extubation and recovery.
Evaluation of PVR
Evaluation of PVR occurred periprocedurally, prior to discharge, and at follow-up. During TTE-TAVR, immediate postdeployment images were obtained in the parasternal long-axis, parasternal short-axis, apical five-chamber, and apical long-axis (three-chamber) views. When PVR was present, color and continuous wave Doppler assisted in the assessment, primarily providing jet width diameter, pressure half-time, and circumferential extent of PVR. Images were reviewed in real time in conjunction with aortography by both the attending echocardiographer and interventionalist, to discuss the risks and benefits of further therapy (postdilation, etc.) In the setting of TEE-TAVR, images were obtained in the midesophageal aortic long- and short-axis views under a similar protocol.
Prior to discharge and at follow-up, TTEs were performed in the echocardiography lab according to the standard institutional protocol by certified ultrasonographers. All follow-up TTEs were performed at our institution. Formal assessment of PVR was performed using the following parameters when possible: regurgitant fraction, effective regurgitant orifice area, jet width diameter, aortic valve pressure half-time, circumferential extent of PVR, and pulsed-wave Doppler assessment of diastolic flow reversal in the descending aorta. Severity of PVR was graded per the Valve Academic Research Consortium-2 (VARC-2) definitions. Prior to the 2013 release of the VARC-2 criteria, PVR assessment relied on jet density, jet width, and jet deceleration time as per the original VARC criteria for PVR in the setting of surgically implanted valves. As the criteria for grading PVR changed during our study period, strict uniformity in our assessment of PVR was not feasible. We used all available parameters for assessment of PVR to reach a consensus with slightly more emphasis on jet density and jet width as these measures were consistently measured in all echocardiograms before and after the release of VARC-2. Additionally, jet location is important for identification of central versus paravalvular insufficiency. After VARC-2, the inclusion of the circumferential extent of PVR further assisted this distinction. Severity of PVR was initially extracted from reports. Given the potential for variability, each case was then reviewed and confirmed in a blinded fashion using VARC-2 criteria by one investigator (S.L.) before inclusion in our analysis. Despite blinded review, a discrepancy between our blinded investigator and the prior report was rare. Measurements were made using Syngo Dynamics Workspace (V5.05, Siemens Medical Solutions, Malvern, PA). The predischarge, 30-day follow-up, and 1-year TTEs with formal assessments of PVR were used in the analysis.
Statistical Analysis
Continuous variables are presented as means (standard deviation) or as median (interquartile range), and categorical variables are represented as proportions (%). Independent sample t -tests and χ 2 tests were used to compare continuous and categorical variables, respectively. Binary logistic regression with PVR dichotomized as “none and trace” versus “mild or more” as the dependent variable was done to determine whether the TAVR approach was an independent predictor of PVR at discharge. A separate regression model using the occurrence of at least mild PVR at discharge, intraprocedural requirement of balloon postdilation, or second valve insertion as a combined outcome was also done to account for intraprocedural interventions related to PVR. Patient’s gender, body mass index (BMI), TAVR approach, use of multidetector CT for valve sizing, valve type and size, and learning curve accounted for as year of procedure were added into both multivariable models. A final table comparing our first 50 TTE-TAVRs with the last 50 by χ 2 tests is presented summarizing the incidence of PVR, balloon postdilation, and second valve implantation in our early and late experiences with TTE-TAVR. Two-tailed P values ≤.05 were considered statistically significant. Analyses were performed using IBM SPSS Statistics Version 21 (IBM, Armonk, NY).
Results
Patient and Procedural Characteristics
A total of 454 patients underwent TAVR via the TF approach and received either an Edwards SAPIEN or SAPIEN-XT valve. Of those, 220 (49%) had TEE-TAVR and 234 (52%) had TTE-TAVR ( Table 1 ). At baseline, TTE-TAVR patients had lower aortic mean and peak transvalvular gradients (42 vs 48 mmHg; P < .001) compared with TEE-TAVR patients. Otherwise there were no significant differences in ejection fraction, aortic valve area, or the percentage of patients with baseline aortic, mitral, or tricuspid regurgitation between the two groups ( Table 1 ). Patients who underwent TTE-TAVR had slightly lower Society of Thoracic Surgeons (STS) predicted risk of mortality (10% vs 11%; P = .026) and more commonly received a SAPIEN-XT valve (52% vs 38%; P = .003) compared with those who had TEE-TAVR. Notably, TTE-TAVR was associated with a reduced length of stay ( P < .001) and total intensive care time ( P < .001).
| Variables | Standard TEE-TAVR ( n = 220) | Minimalist TTE-TAVR ( n = 234) | P value |
|---|---|---|---|
| Age (y) | 81 (10) | 82 (8) | .5 |
| Male | 127 (58%) | 137 (59%) | .9 |
| BMI (kg/m 2 ) | 27 (6) | 27 (5) | .5 |
| Caucasian | 194 (89%) | 202 (87%) | .6 |
| Clinical characteristics | |||
| Diabetes mellitus | 95 (43%) | 91 (40%) | .4 |
| Hypertension | 213 (97%) | 229 (98%) | .8 |
| Hyperlipidemia | 199 (91%) | 221 (98%) | .1 |
| Peripheral arterial disease | 47 (22%) | 44 (19%) | .6 |
| History of myocardial infarction | 69 (31%) | 66 (28%) | .5 |
| Heart failure within 2 weeks of TAVR | 205 (94%) | 213 (94%) | .9 |
| Previous revascularization | 104 (47%) | 119 (54%) | .5 |
| Previous valve replacement | 59 (27%) | 77 (33%) | .2 |
| Glucose (mg/dL) | 117 (36) | 116 (36) | .7 |
| Hemoglobin (g/dL) | 12 (2) | 11 (2) | .7 |
| Creatinine (mg/dL) | 1.3 (1.0) | 1.4 (1.8) | .4 |
| Baseline echocardiographic parameters | |||
| Left ventricular ejection fraction, % | 49 (14) | 51 (14) | .1 |
| Aortic valve area (cm 2 ) | 0.8 (0.4) | 0.8 (0.4) | .9 |
| Aortic mean transvalvular gradient (mmHg) | 48 (17) | 42 (14) | <.001 |
| Aortic peak transvalvular gradient (mmHg) | 81 (28) | 71 (23) | <.001 |
| Pulmonary artery systolic pressure (estimated) (mmHg) | 46 (14) | 46 (15) | .9 |
| Aortic valve regurgitation (≥moderate) | 49 (22%) | 54 (24%) | .7 |
| Mitral valve regurgitation (≥moderate) | 54 (24%) | 45 (20%) | .3 |
| Tricuspid valve regurgitation (≥moderate) | 42 (19%) | 37 (16%) | .5 |
| Procedural characteristics | |||
| Predicted risk of mortality (STS), % | 11 (7) | 10 (5) | .026 |
| Multidetector CT for annulus sizing | 19 (9%) | 66 (28%) | <.001 |
| Procedure success rate by VARC-2 criteria | 202 (92%) | 207 (89%) | .4 |
| Valve type | |||
| SAPIEN | 137 (62%) | 113 (48%) | .003 |
| SAPIEN-XT | 83 (38%) | 121 (52%) | |
| Valve size (mm) | 25 (2) | 25 (2) | .9 |
| Required second valve in procedure | 5 (2%) | 15 (7%) | .026 |
| Required balloon postdilation | 34 (17%) | 75 (38%) | <.001 |
| Length of stay (days) | 7 (6) | 5 (5) | .001 |
| Total hours in ICU | 51 (113) | 23 (42) | .001 |
Although success rates by the VARC-2 criteria were similar between the two approaches (89% for TTE-TAVR vs 92% for TEE-TAVR; P = .4), patients who underwent TTE-TAVR were more likely to require balloon postdilation (38% vs 17%; P < .001) and insertion of a second valve at the time of the procedure compared with TEE-TAVR ( n = 15, 7% vs n = 5, 2%; P = .026). The reasons for second valve insertion were as follows: significant PVR after deployment and postdilation (11 vs 3), valve misplacement (2 vs 2), and significant central regurgitation (2 vs 0) in TTE-TAVR and TEE-TAVR patients, respectively. When classified by approach (TTE vs TEE) and valve type, there was significantly more balloon postdilation in the TEE-TAVR group receiving the SAPIEN-XT valve (SAPIEN: n = 14, 11%; vs SAPIEN-XT: n = 20, 30%; P = .001). In the TTE group, there was no difference in incidence of balloon postdilation based on valve type.
Major intraprocedural complications were rare. In the TEE-TAVR group, there were no incidences of annular rupture, no incidences of coronary obstruction, and two incidences of cardiac tamponade. In the TTE-TAVR group, there was one incidence of annular rupture, no incidences of coronary obstruction, and one incidence of cardiac tamponade. Conversion from TTE to TEE was attempted in one patient, although the probe did not pass and TEE was aborted in this case. Fluoroscopy time (TTE-TAVR 27.04 minutes vs TEE-TAVR 27.02 minutes; P = .787) and contrast volume (TEE-TAVR 120 mL vs TTE-TAVR 125 mL; P = .404) were not statistically different between the groups. Postprocedural pacemaker implantation was also similar between the groups (TTE-TAVR: n = 7, 3% vs TEE-TAVR: n = 10, 4%; P = .534).
Incidence of PVR
TTEs were available for all 454 patients prior to discharge, for 385 patients at 30 days after the procedure, and 186 patients at 1 year ( Table 2 ). The overall incidence of at least mild PVR was 35%, with 12 patients (2.6%) who had moderate and only three (0.7%) who had severe PVR. There were no statistically significant differences in the incidence of PVR between the TTE-TAVR and TEE-TAVR groups postprocedurally ( P = .120) and at 30 days ( P = .359). No difference in PVR was noted at 1 year ( P = .173), although this is limited by incomplete 1-year follow-up. The incidence of at least mild PVR was comparable between TTE-TAVR and TEE-TAVR (33% vs 38%; P = .326). When further stratified by valve type, we did not find a statistically significant difference in PVR between patients who received the SAPIEN and those who received the SAPIEN-XT valve within each approach ( Figure 2 ).
| PVR grade | Approach | Postprocedure ( N = 454) | 30 days ( n = 385) | 1-Year ( n = 186) |
|---|---|---|---|---|
| None | TTE-TAVR | 125 (53%) | 109 (56%) | 53 (60%) |
| TEE-TAVR | 119 (54%) | 95 (49%) | 47 (48%) | |
| Trace | TTE-TAVR | 32 (14%) | 13 (7%) | 6 (7%) |
| TEE-TAVR | 18 (8%) | 17 (9%) | 3 (3%) | |
| Mild | TTE-TAVR | 69 (29%) | 64 (33%) | 28 (31%) |
| TEE-TAVR | 76 (35%) | 75 (39%) | 45 (46%) | |
| Moderate | TTE-TAVR | 5 (2%) | 5 (3%) | 2 (2%) |
| TEE-TAVR | 7 (3%) | 5 (3%) | 2 (2%) | |
| Severe | TTE-TAVR | 3 (1%) | 2 (1%) | 0 (0%) |
| TEE-TAVR | 0 (0%) | 0 (0%) | 0 (0%) |
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