Transcatheter aortic valve implantation (TAVI) with the Cribier-Edwards prosthesis may provide an alternative to conventional aortic valve replacement in high-risk patients with aortic stenosis. Previous studies have indicated that TAVI is feasible in this patient population. Transcatheter implantation of a Cribier-Edwards prosthesis was attempted in 55 patients in a United States Food and Drug Administration–approved prospective observational study. Clinical and echocardiographic outcomes were assessed in hospital and at 30 days, 6 months, and 12 months. Fifty-five patients (55% women, mean age 83 years) with a mean aortic valve area of 0.57 ± 0.14 cm 2 and a mean logistic European System for Cardiac Operative Risk Evaluation score of 33.5 ± 17.0% were enrolled. Transcatheter heart valves were implanted successfully in 48 patients (87%). Mean echocardiographic aortic valve area improved from 0.56 ± 0.14 to 1.6 ± 0.48 cm 2 after the procedure (p <0.0001). Thirty-day all-cause mortality and major adverse cardiac and cerebrovascular events were 7.3% and 20%, respectively. There were also 7 major procedural vascular complications (12.7%). Mortality and major adverse cardiac and cerebrovascular events increased to 23.6% and 32.7%, respectively, at 1 year, with most late events related to underlying co-morbidities. Mean New York Heart Association functional class improved from 3.22 ± 0.66 at baseline to 1.50 ± 0.85 at 1 year follow-up (p <0.001). In conclusion, TAVI in high-risk patients with aortic stenosis was feasible, with sustained clinical benefit at 12 months. Procedural complications and late major adverse cardiac and cerebrovascular events, however, overshadowed the overall clinical benefit of TAVI in this high-risk patient population.
The concept of placing heart valves on catheters for deployment at remote intracardiac sites was first introduced in 1965. However, transcatheter aortic valve implantation (TAVI) only gained momentum in the past decade, when the concept of a balloon-expandable aortic valve was first investigated in an animal model. The first successful human case of TAVI was performed in 2002 by Cribier et al in a patient who was considered inoperable. Since that landmark case, the combination of technology enhancements, revised patient selection, and improved operator techniques (including the retrograde transfemoral and anterograde transapical approaches) have resulted in reduced complications and improved clinical outcomes with balloon-expandable and self-expanding TAVI devices. The purpose of this report is to describe the first series of patients treated in the United States with retrograde TAVI in patients with high-risk aortic stenosis (AS) using a balloon-expandable equine pericardial stent-valve prosthesis.
Methods
The Percutaneous Endovascular Implantation of Valves (REVIVAL) study was a United States Food and Drug Association–approved clinical trial using the balloon-expandable Cribier-Edwards aortic bioprosthesis (Edwards Lifesciences, Inc., Irvine, California). This prospective, nonrandomized, observational study evaluating the safety and feasibility of retrograde TAVI in 55 patients at high risk for surgical aortic valve replacement (AVR) was conducted at 3 centers: William Beaumont Hospital (Royal Oak, Michigan), Columbia University–New York Presbyterian Medical Center (New York, New York), and the Cleveland Clinic Foundation (Cleveland, Ohio). The study design was approved by institutional review boards at all sites, and signed written informed consent was obtained from all patients and/or their closest living relatives. There was an independent data safety monitoring board and a clinical events committee to review all adverse events and to provide trial oversight. Echocardiograms were independently analyzed by an echocardiographic core laboratory (Massachusetts General Hospital, Boston, Massachusetts).
Inclusion criteria for the study were (1) age ≥70 years, (2) symptomatic degenerative calcific AS with a calculated valve area <0.7 cm 2 , and (3) logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) score ≥20%. Patients with logistic EuroSCOREs <20% could also be enrolled if medical conditions existed that were not captured in the risk-scoring algorithm that precluded them from surgery, such as porcelain aorta, radiation treatment of the sternum, severe chest wall deformities, marked frailty, or severe chronic obstructive lung disease. In addition, all patients were required to undergo independent assessments by a cardiac surgeon documenting expected risk for surgical mortality at 30 days of >20%. Key exclusion criteria included preexisting prosthetic heart valve in any position; therapeutic invasive cardiac procedure other than balloon aortic valvuloplasty within 1 month of the index procedure; renal insufficiency (creatinine >3 mg/dl); gastrointestinal hemorrhage or stroke within 6 months; myocardial infarction (MI) within 14 days; known contraindication to aspirin, heparin, ticlopidine, or clopidogrel; aortic annular diameter <18 or >25 mm; significant untreated coronary disease; severe left ventricular dysfunction (left ventricular ejection fraction <20%); and life expectancy <12 months.
Screening studies were performed in all patients before enrollment. These included angiography (ascending aorta, coronary arteries, and iliofemoral vessels), computed tomographic angiography or magnetic resonance angiography to carefully evaluate suitability for the placement of large sheaths in the peripheral vasculature, and transthoracic echocardiography (or transesophageal echocardiography in patients without adequate transthoracic images). In addition to standard echocardiographic measurements, a careful assessment of aortic annular size was performed. If the annulus measured 18 to 21 mm, a 23-mm transcatheter heart valve (THV) was used, and if the annulus was 21 to 25 mm, a 26-mm THV was used. Baseline National Institutes of Health Stroke Scale and quality-of-life surveys were performed in all patients.
Patients were premedicated with aspirin (325 mg) and clopidogrel (300 to 600 mg). A transfemoral retrograde approach was used through either percutaneous catheter insertion or direct common femoral artery surgical exposure. In patients with insufficient iliofemoral anatomy to accommodate the large sheaths (either a 22Fr or a 24Fr sheath was required for the smaller and larger THV sizes), a retroperitoneal approach with direct access into the iliac artery was planned. Standard balloon aortic valvuloplasty was performed using a balloon 2 to 3 mm smaller in diameter than the intended transcatheter valve size.
The Cribier-Edwards aortic valve prosthesis consists of a trileaflet equine pericardial tissue valve mounted inside a stainless steel stent. The left ventricular portion of the stent is covered by a polytetrafluoroethylene skirt ( Figure 1 ). The stent-valve prosthesis is available in 2 sizes: 23 and 26 mm. The 23-mm valve is 14.5 mm in height, and the 26-mm valve is 16 mm in height. The valve was crimped onto a standard 3-cm-length balloon catheter, which was loaded inside a tip-deflecting catheter. The stent-valve prosthesis was positioned in a region just below the aortic annulus using fluoroscopic guidance. Transesophageal echocardiography was performed to confirm the THV’s position. The prosthesis was deployed during rapid right ventricular pacing (at heart rates from 180 to 210 beats/min) to minimize forward cardiac output and movement of the valve. If there was significant (>2+) paravalvular regurgitation on transesophageal echocardiography, repeat dilatation was usually performed with slightly more volume in the valve deployment balloon. The sheath was then removed, and the arteriotomy was repaired surgically.
After the index procedure, transthoracic echocardiography and clinical assessments were performed at 7 days, 30 days, 3 months, 6 months, 1 year, and annually for 5 years. Formal quality-of-life surveys were performed at 30 days, 6 months, and 1 year. Chest x-rays and electrocardiography were performed at each clinic visit.
Major adverse cardiac and cerebrovascular events were defined as death (all cause), MI (ST-segment elevation MI and non–ST-segment elevation MI), emergent cardiac surgery, valve thrombosis, structural valve deterioration, or stroke. Q-wave MI was defined as the development of pathologic Q waves in 2 contiguous leads with abnormal creatine kinase-MB or troponin level, and non-Q-wave MI was defined as elevation of creatine kinase-MB or troponin >3 times normal with either ischemic electrocardiographic changes or cardiac symptoms. The MI definitions were consistent with the definition of MI proposed by the Academic Research Consortium for drug-eluting stent trials. Major vascular complications included iliac or femoral artery perforation requiring interventional or surgical treatment, any unplanned surgery for a procedure-related vascular event, or aortic dissection (abdominal or thoracic) requiring interventional or surgical treatment.
Baseline characteristics and outcomes are reported using descriptive statistics: categorical variables as frequencies and continuous variables as means or medians and SDs. Comparisons between the 2 groups were performed using chi-square tests or Fisher’s exact tests for categorical variables and Student’s t tests for continuous variables. The same parameters were evaluated for changes from before the procedure and 1, 6, and 12 months using a repeated-measures mixed model for continuous outcomes, and ordinal logistic regression, assuming proportional odds, was used for ordinal outcomes with adjustment for baseline values. Two-sided p values <0.05 were considered statistically significant.
Results
From December 2005 to November 2006, TAVI was attempted in 55 patients (30 women, 25 men; mean age 83 ± 7 years, range 69 to 100). Baseline patient characteristics are listed in Table 1 . All patients had severe symptomatic AS, with a mean transvalvular gradient of 44.7 ± 16.3 mm Hg (range 13 to 74), a mean peak gradient of 80.0 ± 26.0 mm Hg (range 22 to 132), and a mean calculated valve area of 0.57 ± 0.14 cm 2 (range 0.3 to 0.9). The mean calculated logistic EuroSCORE was 33.5 ± 17% (range 8% to 83%). Only 9 patients had logistic EuroSCOREs <20%. These patients were enrolled because of inoperable surgical conditions not captured by the logistic EuroSCORE, including porcelain aorta (3 patients), chest wall radiation (2 patients), chest wall deformities (1 patient), severe obstructive or restrictive lung disease (2 patients), Felty’s syndrome (1 patient), and severe cirrhosis (1 patient). The mean Society of Thoracic Surgeons score for the enrolled patients was 13.0 ± 7.1% (range 4% to 31%).
| Variable | Value |
|---|---|
| Age (years) | 82.8 ± 6.8 (69–100) |
| Women | 30 (55%) |
| New York Heart Association class III or IV | 48 (87%) |
| Angina pectoris | 19 (39%) |
| Syncope | 10 (18%) |
| Diabetes mellitus | 17 (31%) |
| Peripheral vascular disease | 15 (28%) |
| Previous MI | 18 (35%) |
| Any previous cardiac surgery | 22 (40%) |
| Previous percutaneous coronary intervention | 20 (39%) |
| Previous aortic valvuloplasty | 18 (33%) |
| Previous cerebrovascular event | 10 (18%) |
| Chronic pulmonary disease | 14 (26%) |
| Chronic renal insufficiency | 10 (18%) |
| Porcelain aorta ⁎ | 6 (11%) |
| Previous chest wall radiation | 4 (7.3) |
| Chest wall deformities | 3 (6%) |
| Body surface area (m 2 ) | 1.78 ± 0.21 |
| Logistic EuroSCORE (%) | 33.5 ± 17 (8–83) |
| 20–40 | 30 (55%) |
| 41–60 | 12 (22%) |
| >61 | 4 (7%) |
| Society of Thoracic Surgeons risk score | 13.0 ± 7.1 (4–31) |
⁎ Severe ascending aortic calcification making surgery prohibitively high risk.
Vascular access was obtained successfully in 52 of the 55 patients (94%). Of the 3 patients with failed sheath access, there were 2 arterial injuries during insertion that required surgical repair using an interposition graft. In the third patient, the sheath kinked repeatedly, and the procedure was aborted. The transfemoral approach was successfully used in 44 patients. Because of the presence of external iliac or common femoral disease, the retroperitoneal approach with direct iliac access was used in the other 8 patients. In 6 of these, this approach was planned from the outset, while in the other 2, an iliac conduit was used after transfemoral access failure.
A prosthetic aortic valve was implanted successfully in 48 of the 55 patients (87%; Figure 2 ). Of these, 29 patients received 26-mm valves (mean annular diameter 20.2 ± 1.6 mm), and 19 patients received 23-mm valves (mean annular diameter 18.7 ± 1.5 mm). In 1 of these patients, there was severe central aortic regurgitation after deployment because of failed leaflet coaptation. In this case, a second valve was implanted within the first valve, with resolution of the aortic regurgitation. In the 7 patients in whom valve deployment was unsuccessful, 3 were due to failed vascular access as described previously. In 2 of these patients, balloon valvuloplasty was performed. The third patient had multiple-organ failure after repair of the vascular injury and died 14 days after the procedure. Three of the 4 other unsuccessful procedures were due to severe aortic valve calcification resulting in failure to advance the stent-valve prosthesis across the diseased native valve. In 1 of these patients, the aortic prosthesis was deployed in the descending aorta, and the patient was discharged in stable condition. In the other 2 patients, efforts to cross the diseased valve resulted in ascending aortic dissections; 1 was taken emergently to the operating room for an ascending aortic graft and AVR but died 3 days later, and the other patient was treated medically and died the next day. The final failed deployment was caused by malplacement of the stent-valve too low into the left ventricular cavity, which caused severe aortic regurgitation, subsequent embolization of the THV into the left ventricle, and the only procedural death.
In 11 patients (20%), there were in-hospital major adverse cardiac and cerebrovascular events, including 4 in-hospital deaths (7.3%) due to ascending aortic dissection (2 patients), valve embolization (1 patient), and vascular injury with multiple-organ system failure (1 patient) ( Table 2 ). All of these in-hospital deaths occurred in patients in whom the stent-valve was not successfully delivered. In addition, there were 5 strokes (9.1%): 2 major intraprocedural strokes (1 embolic and 1 hemorrhagic) and 3 minor strokes without residual neurologic deficits at 30 days. There were 2 periprocedural non–ST-segment elevation MIs (3.6%), 1 due to obstruction of the left main coronary from a displaced bulky calcified leaflet, which was successfully treated with a left main stent, and another due to severe ischemia associated with prolonged hypotension after a ruptured iliac artery.
| Variable | In Hospital | Follow-Up (months) | ||
|---|---|---|---|---|
| 1 | 6 | 12 | ||
| Major adverse cardiac and cerebrovascular events | 11 (20%) | 11 (20%) | 14 (25%) | 18 (33%) |
| Death | 4 (7%) | 4 (7%) | 9 (16%) | 13 (24%) |
| Cerebrovascular accident | 5 (9%) | 5 (9%) | 5 (9%) | 7 (13%) |
| Major | 2 (4%) | 2 (4%) | 2 (4%) | 4 (7%) |
| Minor | 3 (5%) | 3 (5%) | 3 (5%) | 3 (5%) |
| MI | 2 (4%) | 2 (4%) | 2 (4%) | 2 (4%) |
| Vascular complications | 7 (13%) | 7 (13%) | 8 (14%) | 9 (16%) |
| Repeat balloon dilatation | 0 | 0 | 1 (2%) | 1 (2%) |
| Structural valve deterioration | 0 | 0 | 0 | 0 |
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