Re-operation after coronary artery bypass grafting (CABG) is associated with increased risk for morbidity and mortality. Transcatheter aortic valve implantation (TAVI) is an alternative for patients with aortic stenosis, but the outcomes of patients with a history of CABG are unknown. The aim of this study was to explore the association between previous CABG and the outcome of patients undergoing TAVI. Out of 372 consecutive patients who underwent TAVI from 2007 to 2013, 122 (32.8%) had previous CABG, whereas 250 (67.2%) did not. A comparison was made between groups. Subgroup analysis compared patients with and without previous CABG in 3 patient subsets: inoperable, operable, and those who underwent transapical TAVI. Patients with previous CABG were younger (81.99 ± 6.78 vs 84.81 ± 7.06 years, respectively, p <0.001). These patients also had more high-risk features (e.g., peripheral vascular disease, previous myocardial infarction, past cerebrovascular disease, and lower average left ventricular ejection fraction (p <0.05 for all). Procedural aspects were mostly similar between groups. No disparities in mortality rates at 1 year were noted (22.1% vs 21.6%, respectively, p = 0.91). Subgroup analyses yielded similar outcomes for all 3 groups. In conclusion, although patients with previous CABG present with more high-risk features, they share similar short- and long-term outcomes with patients without previous CABG, irrespective of their surgical risk. This includes patients who underwent transapical access. TAVI in patients with previous CABG is safe and does not confer a significant risk for adverse outcome.
Surgical replacement of the aortic valve was considered for years to be the gold standard for treating patients with severe, symptomatic aortic stenosis (AS). More recently, transcatheter aortic valve implantation (TAVI) has emerged as a new alternative that enables a minimally invasive, percutaneous deployment of a bioprosthetic valve. The pivotal placement of aortic transcatheter valve (PARTNER) trial had established the merits of TAVI in both inoperable and high risk or operable patients. Because AS is mainly a disease of the elderly, a significant proportion of these patients have undergone previous coronary artery bypass grafting (CABG) surgery, which puts them at high risk for a redo operation. The outcome of patients with previous CABG who underwent TAVI is not established. The aim of this study was to evaluate the characteristics and outcomes of patients undergoing TAVI with previous CABG compared with patients with no previous CABG in a large volume TAVI center. The secondary aim was to evaluate whether previous CABG is associated with outcome discrepancies in inoperable patients, operable patients, and patients who underwent TAVI through transapical access.
Methods
Consecutive patients with severe, symptomatic AS who underwent TAVI from 2007 to 2013 were included and grouped according to the presence or absence of previous CABG surgery. The institutional review board of MedStar Washington Hospital Center approved this study. The eligibility for TAVI was based on the consensus of the Heart Team, which includes interventional cardiologists and cardiothoracic surgeons. All patients underwent screening for eligibility that included physical examination, surgical risk determination (Society of Thoracic Surgeons [STS] score), frailty tests, echocardiography, coronary and peripheral vessel angiography, and computerized tomography angiography. The criteria for eligibility followed the definitions from the PARTNER trials, the US CoreValve Pivotal Trial, and the Food and Drug Administration criteria for commercially available TAVI.
In most of the patients, TAVI was performed under conscious sedation through transfemoral access, whereas the remainder of patients underwent transapical or transaortic TAVI.
After access management and successful valvuloplasty, the prosthetic valve (either self-expandable Medtronic CoreValve [Medtronic, Minneapolis, Minnesota] or the balloon-expandable SAPIEN/SAPIEN XT Transcatheter Heart Valve [Edwards Lifesciences LLC, Irvine, California]) was advanced through the native valve and inflated under rapid pacing. In all SAPIEN procedures, the entire procedure was monitored by transesophageal echocardiography, whereas transthoracic echocardiography was performed immediately after deployment in CoreValve implantation. Unfractionated heparin was used in all procedures (60 IU/kg titrated to activated clotting time of 250 to 300 seconds). After procedure, the patients were recommended to take aspirin (81 mg/day) and clopidogrel (75 mg/day) for 1 month.
Prespecified data were collected prospectively for all patients. This included demographics, clinical, laboratory, procedural, and postprocedural data. Clinical data included medical history, STS score, imaging data (echocardiogaphy, angiography, and computerized tomography) and laboratory indices. Medical history was retrieved from the patient’s chart and referring physician’s notes. Procedural data included valve type and size, access closure device used, amount of contrast and radiation used, and documentation of adverse events during the procedure. Postprocedural data used hospital records as a primary source for laboratory results, length of stay, and in-hospital complications. Long-term follow-up was based on the clinical trial requirements and either office visit or telephone call. Clinical events were adjudicated by an independent cardiologist who determined the nature of the event.
For the present analysis, patients were grouped according to having previous CABG or the absence of this demographic detail. A comparison of the baseline characteristics, procedural data, and both short- and long-term outcomes was performed. A further comparison between patients with a history of previous CABG and those without was performed in 2 prespecified subgroups: patients deemed inoperable and patients with high or intermediate surgical risk. The surgical risk for each patient was determined by a cardiothoracic surgeon and was assisted by the calculated STS score. The disposition for inoperability/high/intermediate surgical risks followed the definitions from the PARTNER trial: Cohort A consists of patients at high or intermediate risk, whereas Cohort B includes inoperable patients. To evaluate the differences in the outcome of patients who were eligible for a redo operation versus those who were inoperable, a prespecified group analysis compared patients who underwent CABG with those who did not in each of the 2 risk cohorts (A and B separately). A further subanalysis was conducted to compare the characteristics and outcomes of patients with and without previous CABG who underwent transapical access for TAVI.
Outcome end points were in accordance with Valve Academic Research Consortium definitions. These include, among others, the rates of mortality, vascular complications, stroke, acute kidney injury, postprocedural myocardial infarction, postprocedural atrial fibrillation, and the need for permanent pacemaker implantation.
Statistical analysis was performed using SAS, version 9.2 (SAS Institute Inc., Cary, North Carolina). Continuous variables are expressed as mean ± SD for normally distributed variables. Categorical variables are expressed as percentages. Student t test was used to compare continuous variables, and the chi-square or Fisher’s exact test was used to compare categorical variables. Survival rates up to 1 year were computed using the Kaplan-Meier method, and differences in parameters were assessed using the log-rank test. The Cox proportional hazard model was utilized to evaluate the hazard ratio for events. Statistically significant differences were defined as p <0.05.
Results
From 2007 to 2013, 372 consecutive patients underwent TAVI at our institution. Of them, 122 (32.8%) had previous CABG, whereas 250 (67.2%) did not. As listed in Table 1 , baseline characteristics differed between the 2 groups; patients with previous CABG were younger, more often men, and weighed more compared with patients with no previous CABG ( Table 1 ). Other co-morbidities were also more frequent in the patients with previous CABG (e.g., peripheral vascular disease and lower left ventricular ejection fraction).
| Variable | CABG Surgery | p Value | |
|---|---|---|---|
| Yes (n = 122) | No (n = 250) | ||
| Age (yrs) | 81.99 ± 6.78 | 84.81 ± 7.06 | <0.001 |
| Men | 90 (73.8) | 91 (36.4) | <0.001 |
| STS risk score | 10.90 ± 5.13 | 10.29 ± 4.32 | 0.280 |
| Inoperable | 59 (48.3) | 119 (47.6) | 0.91 |
| Weight (kg) | 82.44 ± 18.33 | 74.09 ± 20.25 | 0.005 |
| Body mass index (kg/m 2 ) | 28.23 ± 5.93 | 26.83 ± 6.65 | 0.149 |
| Body surface area (m 2 ) | 1.93 ± 0.20 | 1.77 ± 0.25 | <0.001 |
| Systemic hypertension ∗ | 113 (92.6) | 231 (92.4) | 0.939 |
| Diabetes mellitus | 45 (36.9) | 70 (28.0) | 0.082 |
| Hyperlipidemia | 112 (91.8) | 176 (71.3) | <0.001 |
| Chronic obstructive pulmonary disease | 31 (25.8) | 83 (33.5) | 0.138 |
| Peripheral vascular disease | 57 (51.4) | 75 (30.9) | <0.001 |
| Cerebrovascular event/transient ischemic attack | 34 (27.9) | 44 (17.9) | 0.027 |
| Atrial fibrillation/flutter | 46 (37.7) | 100 (40.0) | 0.670 |
| Renal insufficiency | 71 (60.2) | 135 (55.3) | 0.383 |
| Dialysis dependency | 0 | 4 (1.6) | 0.308 |
| Previous balloon aortic valvuloplasty | 35 (41.7) | 93 (48.2) | 0.317 |
| Previous myocardial infarction | 31 (27.7) | 23 (9.2) | <0.001 |
| Number of diseased vessels | 2.55 ± 0.64 | 0.52 ± 0.8 | <0.001 |
| Congestive heart failure | 71 (95.5) | 157 (96.3) | 1.0 |
| Preprocedural echocardiographic parameters | |||
| Ejection fraction (%) | 48.33 ± 14.26 | 55.39 ± 12.53 | <0.001 |
| Mean aortic valve gradient | 44.07 ± 11.16 | 50.86 ± 13.24 | <0.001 |
| Maximum aortic valve velocity | 4.22 ± 0.49 | 4.50 ± 0.57 | <0.001 |
| Aortic regurgitation: moderate | 2 (2.3) | 9 (4.2) | 0.520 |
| Aortic regurgitation: moderate to severe/severe | 0 | 0 | |
| Mitral regurgitation: moderate | 12 (11.3) | 19 (8.3) | 0.381 |
| Mitral regurgitation: moderate to severe | 0 | 4 (1.8) | 0.171 |
| Mitral regurgitation: severe | 0 | 1 (0.4) | 1.0 |
| Mean luminal diameter: right illio-femoral arteries | 7.36 ± 1.19 | 7.26 ± 1.19 | 0.536 |
| Mean luminal diameter: left illio-femoral arteries | 7.39 ± 1.13 | 7.21 ± 1.17 | 0.251 |
∗ History of systemic hypertension diagnosed and/or treated with medication or currently being treated with diet and/or medication by a physician.
Aside from differences in the usage rate of smaller valves in patients with no CABG history (23-mm valve 64.0% vs 34.2%, respectively, p <0.001), no differences were noted in the procedural aspects of TAVI, such as access, use of resources, and intraprocedural complications ( Table 2 ). Further, no differences were noted in the in-hospital, 30-day, and 1-year outcomes ( Table 3 ), aside from longer hospital stay seen in patients with no previous CABG (10.21 ± 8.23 vs 8.56 ± 5.79 days, respectively, p = 0.026). Mortality rates at 30 days and 1 year did not differ between those with previous CABG and those without (9.8% vs 10.0%, respectively, p = 0.96 and 22.1% vs 21.6%, respectively, p = 0.91).
| Variable | CABG Surgery | p Value | |
|---|---|---|---|
| Yes (n = 122) | No (n = 250) | ||
| Valve size | |||
| 23 mm | 41 (34.2) | 162 (64.0) | <0.001 |
| 26 mm | 73 (60.8) | 81 (32.0) | <0.001 |
| 29 mm | 3 (2.5) | 7 (2.8) | 1 |
| 31 mm | 3 (2.5) | 3 (1.2) | 0.391 |
| Access | |||
| Transfemoral | 81 (66.4) | 178 (71.2) | 0.344 |
| Transapical | 37 (30.3) | 58 (23.2) | 0.139 |
| Retroperitoneal | 3 (2.5) | 13 (5.2) | 0.221 |
| Direct aortic | 1 (0.8) | 1 (0.4) | 0.549 |
| Resources | |||
| Conscious sedation | 68 (55.7) | 155 (62.0) | 0.247 |
| Contrast media volume used (ml) | 119.35 ± 57.34 | 11.67 ± 76.85 | 0.714 |
| Fluoroscopy | 19.24 ± 57.24 | 21.19 ± 19.52 | 0.213 |
| Intraprocedural complications | |||
| Need for cardiopulmonary bypass | 4 (3.3) | 4 (1.6) | 0.447 |
| Valve migration | 0 | 3 (1.2) | 0.554 |
| Inability to gain access | 4 (3.3) | 8 (3.2) | 1.0 |
| Cardiopulmonary resuscitation/cardioversion | 10 (8.2) | 17 (6.8) | 0.633 |
| Tamponade | 0 | 4 (1.6) | 0.307 |
| Complete atrioventricular block | 2 (1.6) | 12 (4.8) | 0.157 |
| Postdilatation after valve deployment | 6 (5.5) | 10 (4.6) | 0.717 |
| Second valve implantation | 0 | 4 (1.8) | 0.306 |
| Surgery needed postvalve deployment | 0 | 1 (0.5) | 1 |
| Variable | CABG Surgery | p Value | |
|---|---|---|---|
| Yes (n = 122) | No (n = 250) | ||
| Length of stay (days) | 8.56 ± 5.79 | 10.21 ± 8.23 | 0.026 |
| Postprocedure length of stay (days) | 6.62 ± 5.27 | 8.19 ± 7.66 | 0.022 |
| Postprocedural days in coronary care unit (days) | 2.85 ± 4.04 | 3.22 ± 5.37 | 0.463 |
| Major vascular complication | 8 (6.6) | 32 (12.8) | 0.068 |
| Need for access site surgical intervention | 6 (5.1) | 25 (10.3) | 0.1 |
| Need for access site percutaneous intervention | 8 (6.8) | 23 (9.5) | 0.399 |
| Life-threatening bleeding | 7 (5.7) | 25 (10.0) | 0.169 |
| Postprocedure blood transfusions | 53 (43.4) | 125 (50.5) | 0.235 |
| Acute myocardial infarction | 0 | 0 | |
| Acute kidney injury | |||
| Stage 1 | 6 (5.1) | 13 (5.6) | 0.847 |
| Stage 2 | 16 (13.6) | 30 (12.9) | 0.858 |
| Stage 3 | 2 (2.5) | 4 (1.7) | 0.692 |
| Stroke (ischemic and hemorrhagic) | 6 (4.9) | 18 (7.2) | 0.40 |
| Need for intubation post-TAVI | 23 (19.0) | 45 (18.4) | 0.882 |
| New atrial fibrillation | 21 (17.2) | 41 (16.5) | 0.869 |
| Need for pacemaker implantation | 6 (4.9) | 7 (2.8) | 0.369 |
| Moderate aortic regurgitation (echocardiography) | 3 (4.3) | 5 (4.1) | 1.0 |
| Moderate to severe/severe aortic regurgitation (echocardiography) | 0 | 0 | |
| Mortality | |||
| Intraprocedural death | 9 (7.9) | 22 (8.8) | 0.641 |
| 30-day mortality | 12 (9.8) | 25 (10.0) | 0.960 |
| 1-year mortality | 27 (22.1) | 54 (21.6) | 0.907 |
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