Patients with previous coronary artery bypass grafting (CABG) are considered to be at increased perioperative risk for a redo cardiac operation. In the era of transcatheter aortic valve implantation (TAVI), these patients constitute a considerable portion of those with severe aortic stenosis referred for TAVI. We evaluated the impact of previous CABG on transfemoral TAVI outcomes. Patients with severe symptomatic aortic stenosis (n = 515) who underwent transfemoral TAVI were divided according to the presence of history of CABG. Patients with previous valvular surgery were excluded (n = 12). TAVI clinical end points and adverse events were considered according to the Valve Academic Research Consortium 2 definitions. Survival was estimated using Cox regression models at the enter mode with the dependent variable defined as all-cause mortality. Of the total 503 patients who underwent TAVI, 91 (18.1%) had previous CABG. At baseline, patients with previous CABG were younger (80.8 vs 83.1 years, p <0.001), mostly men (85% vs 35%, p <0.001), had more cardiac and vascular co-morbidities, higher mean logistic EuroSCORE (32.8 vs 22; p <0.001), lower ejection fraction (53% vs 56%, p <0.001), and lower AV gradients and larger valve area. At a mean follow-up of 636 days, the overall Valve Academic Research Consortium 2–adjudicated end points did not differ. No differences in mortality were observed at 30 days, 6 months, and 1 year after TAVI (hazard ratio 1.34, p = 0.55, Cox regression). We conclude that patients with previous CABG who underwent TAVI do not have increased risk of periprocedural complications or mortality, although having distinct clinical features compared with the total TAVI population.
Patients with previous coronary artery bypass graft (CABG) surgery, aortic valve replacement (AVR), or mitral valve surgery are considered to be at increased perioperative risk when they undergo a redo cardiac operation. Redo surgery is technically challenging regarding the surgical approach, the myocardial protection, the calcified aortic root, and the need to avoid damage to previous arterial grafts. Transcatheter aortic valve implantation (TAVI) has evolved as an effective treatment in patients with severe symptomatic aortic stenosis (AS) and increased operative risk. TAVI is, therefore, an alternative to surgery for patients with severe AS and a history of heart surgery. Previous studies evaluating the impact of previous surgery on TAVI outcomes included a mixture of different percutaneous approaches, showing that in this population, previous CABG does not increase the risk of adverse outcome compared with patients without a history of cardiac surgery. Additional studies evaluating the outcome of only transapical TAVI in patients after previous cardiac surgery showed no excess risk compared with those with no previous cardiac surgery. The present study evaluates the impact of a previous CABG surgery on the outcome of patients who underwent transfemoral TAVI.
Methods
From March 2009 to March 2014, 515 consecutive patients with severe symptomatic AS underwent transfemoral TAVI at the Tel Aviv Medical Center, a tertiary university hospital, and were included in our ongoing single-center prospective registry of TAVI. Patients were recruited to the present study as part of their participation in the Tel-Aviv Prospective Angiography Study, following the study protocol approval by the institutional review board. Diagnosis of severe AS was based on clinical, echocardiographic, and hemodynamic criteria. All patients were considered high risk for valve surgery with suitability and eligibility for TAVI determined by our heart team including an interventional cardiologist, a cardiac surgeon, and a senior echocardiographist. All patients underwent coronary angiography to identify obstructive coronary artery disease (CAD) during the 6 weeks before the procedure and those with significant lesions (≥70%) in a major epicardial coronary artery determined as clinically significant by the interventional cardiologist underwent percutaneous revascularization. During the same procedure, the femoral arteries were evaluated for future reference.
To evaluate strictly the impact of previous CABG on TAVI outcomes, we excluded 12 patients with previous valve surgery from analysis. The cohort was divided into 2 groups: (1) patients with a history of CABG before TAVI and (2) those without previous CABG.
All TAVI procedures were performed by transfemoral approach using the 18Fr CoreValve device (Medtronic, Minneapolis, Minnesota) or 18Fr/19Fr for the Edwards SAPIEN/SAPIEN XT valve (Edwards Lifesciences LLC, Irvine, California). Prosthetic valve size was selected based on transthoracic echocardiography measurements of the aortic valve annulus diameter. Informed consent was obtained for PCI and TAVI procedures and for being included in our TAVI registry. Dual antiplatelet therapy with aspirin 100 mg and clopidogrel 75 mg daily was given for 6 months after TAVI and prolonged for 12 months for patients treated with drug-eluting stent implantation followed by aspirin therapy alone indefinitely.
Baseline clinical, echocardiographic, and procedural details for TAVI were prospectively recorded for all patients and 1 month, 6 months, and yearly clinical and echocardiographic assessments. TAVI end points were considered according to the updated Valve Academic Research Consortium 2 (VARC-2) definitions.
All data were summarized and displayed as mean ± SD for continuous variables and as number (percentage) of patients in each group for categorical variables. The student’s t and Pearson’s chi-square tests were used to evaluate statistical significance between continuous and categorical variables, respectively. Survival was estimated using Cox regression models at the enter mode. The dependent variable was defined as all-cause mortality and was adjusted to the following patients and procedural characteristics: age, gender, hypertension, dyslipidemia, diabetes mellitus, documented peripheral vascular disease, documented history of CAD, previous MI, previous PCI, previous CABG, history of cerebrovascular accident, chronic atrial fibrillation, chronic obstructive pulmonary disease, creatinine clearance test, logistic EuroSCORE, preprocedural echocardiographic measurements of left ventricular ejection fraction, aortic valve area, and mean pressure gradient across the aortic valve. Analyses were considered significant at a 2-tailed p value <0.05. The SPSS statistical package was used to perform all statistical evaluation (SPSS, Chicago, Illinois).
Results
Our final cohort included 503 patients (age 82.7 ± 6, male gender 44%). History of CABG surgery was present in 91 of these patients (18.1%). All had only 1 previous heart surgery. Significant differences in baseline characteristics existed between patients who underwent TAVIs with or without previous CABG ( Table 1 ). A significantly higher rate of male patients had previous CABG comprising 85% of the previous CABG group (77 of 91) and excessively more than the proportion of men in the entire cohort. Patients with previous CABG were younger (80.8 vs 83.1 years, p <0.001), had more cardiac and vascular co-morbidities, higher mean logistic EuroSCORE (32.8 vs 22; p <0.001), lower ejection fraction (53% vs 56%, p <0.001), and significantly better echocardiographic parameters of severe AS (lower peak and mean gradients and larger valve area).
| Variable | Total Cohort (n=503) | Prior coronary bypass | p value | |
|---|---|---|---|---|
| No (n=412) | Yes (n=91) | |||
| Age (mean±SD, range)(years) | 82.7±6 (range 61-98) | 83.1±6 | 80.8±6 | <0.001 |
| Men | 222 (44%) | 145 (35%) | 77 (85%) | <0.001 |
| Diabetes mellitus | 176 (35%) | 140 (34%) | 36 (40%) | 0.33 |
| Dyslipidemia ∗ | 402 (80%) | 320 (78%) | 82 (90%) | 0.006 |
| Hypertension † | 441 (88%) | 363 (88%) | 78 (86%) | 0.59 |
| Smoker | 145 (29%) | |||
| Height (mean±SD, range)(cm) | 163±8 (range 140-183) | 161±9 | 168±7 | <0.001 |
| Weight (mean±SD, range)(Kg) | 73±15 (range 40-129) | 72±15 | 77±12 | 0.008 |
| Body mass index (mean±SD, range)( Kg/m 2 ) | 27±5 (range 16-43) | 28±5 | 27±4 | 0.27 |
| Peripheral vascular disease | 34 (7%) | 21 (5%) | 13 (14%) | 0.004 |
| Prior Stroke | 56 (11%) | 46 (11%) | 10 (11%) | 1 |
| History of documented coronary artery disease ‡ | 308 (61%) | 217 (53%) | 91 (100%) | <0.001 |
| Prior myocardial infarction | 93 (19%) | 62 (15%) | 31 (34%) | 0.001 |
| Prior percutaneous coronary intervention | 219 (43%) | 165 (40%) | 54 (60%) | 0.001 |
| Atrial fibrillation | 154 (31%) | 124 (30%) | 30 (33%) | 0.62 |
| Prior permanent pacemaker | 59 (12%) | 44 (11%) | 15 (17%) | 0.14 |
| Chronic obstructive pulmonary disease | 89 (18%) | 82 (20%) | 7 (8%) | 0.006 |
| Ejection fraction (mean±SD)(%) | 56±8 | 56±7 | 53±9 | <0.001 |
| EuroSCORE (mean±SD) | 24±14 | 22±13 | 33±16 | <0.001 |
| STS score (mean±SD)(%) | 4.1±2.5 | 4.1±2.3 | 4.5±3 | 0.18 |
| Aortic valve area (mean±SD)(cm 2 ) | 0.72±0.19 | 0.70±0.19 | 0.77±0.17 | 0.002 |
| Peak pressure gradient (mean±SD)(mmHg) | 77±23 | 79±23 | 67±18 | <0.001 |
| Mean pressure gradient (mean±SD)(mmHg) | 47±15 | 48±15 | 41±12 | <0.001 |
| Creatinine clearance (mean±SD)( mL/min) | 52±19 | 51±19 | 56±20 | 0.045 |
∗ Dyslipidemia – LDL > 100 mg/dL or HDL <40 mg/dL or chronic treatment with lipid lowering medication.
† Hypertension – Blood pressure measurements above 140/90 and treatment with chronic medication with the intention of lowering blood pressure.
‡ History of coronary artery disease – prior diagnosis and/or treatment of epicardial artery narrowing of more than 70%.
The overall VARC-2–adjudicated end points did not differ between the groups, with the exception of postprocedural myocardial infarctions that occurred more frequently in patients with previous CABG (5% vs 2%, p = 0.048). Table 2 presents the clinical outcomes after TAVI among the study cohort. The average New York Heart Association class at 30-day follow-up was 1.39 in patients who underwent TAVI without previous CABG compared with 1.32 in the previous CABG group (p = 0.34). Length of hospital stay was not statistically different with an average stay around 8 days.
| Variable | Prior coronary bypass | p value | |
|---|---|---|---|
| No (n=412) | Yes (n=91) | ||
| Mortality (months) | |||
| 1 | 11(3%) | 3 (3%) | 0.72 |
| 6 | 28 (7%) | 9 (10%) | 0.27 |
| 12 | 46 (11%) | 12 (13%) | 0.45 |
| All mortality | 81 (20%) | 22 (24%) | 0.39 |
| Post procedural complications | |||
| Myocardial infarction | 7 (2%) | 5 (5%) | 0.048 |
| Tamponade | 6 (1%) | 0 | 0.6 |
| Cardiogenic shock | 7 (2%) | 3 (3%) | 0.39 |
| Respiratory failure | 23 (6%) | 5 (5%) | 1 |
| Cerebrovascular accident ∗ | 27 (6%) | 4 (4%) | 0.63 |
| Major bleeding | 50 (12%) | 6 (6%) | 0.14 |
| Major vascular complication | 41 (10%) | 6 (6%) | 0.43 |
| Need for permanent pacemaker | 91 (22%) | 22 (24%) | 0.68 |
| Average functional class at 30 days | 1.39 | 1.32 | 0.34 |
| Length of hospitalization (mean±SD) (days) | 8.2±5 | 7.9±6 | 0.7 |
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