Published Studies Focus on TAVI

November 22, 2010—Transcatheter aortic valve implantation (TAVI) is the focus of the current issue of the Journal of the American College of Cardiology: Cardiovascular Interventions, in which Martyn Thomas, MD, reviewed the global experience with percutaneous aortic valve replacement (2010;3:1103–1109). Dr. Thomas described the current data on this technology and the potential for the future role of the technology, including ways to further improve the short- and longer-term results.

Also in the Journal of the American College of Cardiology: Cardiovascular Interventions, Cosmo Godino, MD, et al published a study that aimed to assess clinical outcomes after TAVI performed with the two commercially available valves using three delivery approaches that were selected in a stepwise fashion (2010;3:1110–1121). The investigators noted that limited data exist on the results of a comprehensive TAVI program using different valves with transfemoral, transapical, and transaxillary approaches for the treatment of severe aortic stenosis.

The Milan investigators reported the 30-day and 6-month outcomes of high-risk patients consecutively treated in a single center with either the CoreValve (Medtronic, Inc., Minneapolis, MN) or Edwards Sapien valve (Edwards Lifesciences, Irvine, CA) delivered via the transfemoral or transaxillary approaches. A total of 137 patients underwent TAVI: 107 via transfemoral (46 with CoreValve and 61 with Edwards Sapien) and 15 via transaxillary (12 with CoreValve and three with Edwards Sapien); only the Edwards Sapien valve was used via a transapical approach (n = 15).

The investigators concluded that routine TAVI using both valves with a selection of approaches is feasible and allows treatment of a wide range of patients with good overall procedural success rates at 30 days and 6 months.

The procedural success rate was 93.5% with the transfemoral approach, and the major vascular complication rate was 20.6%. No intraprocedural deaths occurred. The procedural success rates of transapical and transaxillary approaches were 86.6% and 93.3%, respectively. The 30-day mortality rate was 0.9% in transfemoral group and 13.3% in the transapical group, and no deaths occurred with transaxillary access.

The cumulative death rate at 6 months was 12.2% in transfemoral, 26.6% in transapical, and 18.2% in transaxillary groups. At multivariable analysis, logistic EuroSCORE, body surface area, and history of cerebrovascular disease were significantly associated with an increased risk of major adverse cardiac and cerebrovascular events, reported the investigators.

Also in the Journal of the American College of Cardiology: Cardiovascular Interventions, Fabian Nietlispach, MD, et al described the initial human experience with a novel cerebral embolic protection device (2010;3:1133–1138). The investigators found that embolic protection during TAVI seems feasible and might have the potential to reduce the risk of cerebral embolism and stroke.

According to the investigators, the embolic protection device is advanced into the aortic arch via right radial artery access. Once deployed, a porous membrane shields the brachiocephalic trunk and the left carotid artery, deflecting emboli away from the cerebral circulation. Embolic material is not contained or removed by the device. The device was used in four patients (mean age, 90 years) with severe aortic stenosis undergoing balloon aortic valvuloplasty (n = 1) or TAVI (n = 3).

The investigators reported that correct placement of the embolic protection device was achieved without difficulty in all patients. Continuous brachiocephalic and aortic pressure monitoring documented equal pressures without evidence of obstruction to cerebral perfusion. Additional procedural time due to the use of the device was 13 minutes (interquartile range: 12–16 min). There were no procedural complications.

Predischarge cerebral magnetic resonance imaging found no new defects in any of the three patients undergoing TAVI and a new 5-mm acute cortical infarct in the one asymptomatic patient after balloon aortic valvuloplasty alone. No patient developed new neurological symptoms or clinical findings of stroke, the investigators stated.

In another study published in the Journal of the American College of Cardiology: Cardiovascular Interventions, Jan-Malte Sinning, MD, et al sought to determine the influence of baseline renal function and periprocedural acute kidney injury (AKI) on prognosis after TAVI (2010;3:1141–1149). Evidence is growing that renal function is a major predictor of mortality in patients after TAVI, the investigators noted.

In the study, TAVI was performed with the 18-F CoreValve prosthesis via transfemoral access. All-cause mortality was determined at 30 days and 1 year after TAVI in 77 patients with a mean Society of Thoracic Surgeons mortality score of 9.3% ± 6.1% and a mean logistic EuroSCORE of 31.2% ± 17.6%.

The investigators reported that the overall procedural success rate was 98% with one periprocedural death. The 30-day mortality rate was 10%, and 1-year mortality was 26%. The mortality risk increased stepwise across quartiles of baseline serum creatinine. An AKI occurred in 20 of 77 patients: 12 patients (60%) with AKI died during follow-up. The incidence of AKI was related to peripheral arterial disease (65% vs 39%; P = .04), the occurrence of a systemic inflammatory response syndrome (60% vs 21%; P = .002), and postprocedural periprosthetic regurgitation 2+ (35% vs 9%; P = .02). Impaired renal function at baseline reflected by serum creatinine 1.58 mg/dL (hazard ratio, 3.9; 95% confidence interval, 1.6–9.5; P = .002) and the occurrence of AKI (hazard ratio, 5.9; 95% confidence interval, 2.4–14.5; P < .001) that was not related to the amount of contrast dye were strong predictors of 1-year mortality after TAVI.

Impaired renal function at baseline and the occurrence of periprocedural AKI, independent of whether renal function returns to baseline or not, are strong predictors of 30-day and 1-year mortality after TAVI, concluded the investigators.

Finally, in the Journal of the American College of Cardiology: Cardiovascular Interventions, Namal Wijesinghe, MD, et al evaluated TAVI in high-risk patients with bicuspid aortic valve stenosis (2010;3:1122–1125). The investigators noted that TAVI shows promise in the treatment of severe stenosis of tricuspid aortic valves, especially in high-risk patients, but that bicuspid aortic valve stenosis has been considered a contraindication to TAVI.

In this study, 11 patients (aged 52–90 years) with symptomatic, severe bicuspid aortic valve stenosis underwent TAVI at three Canadian tertiary hospitals between May 2006 and April 2010. All patients were considered high risk for surgical aortic valve replacement. Edwards Sapien transcatheter heart valves were used via transfemoral or transapical access, depending on the adequacy of femoral access.

The investigators reported that transfemoral access was used in seven patients and transapical access was used in four patients. There were no intraprocedural complications. Significant symptomatic and hemodynamic improvement was observed in 10 of 11 patients. Baseline aortic valve area of 0.65 ± 0.17 cm² and mean transaortic pressure gradient of 41 ± 22.4 mm Hg were improved to 1.45 ± 0.3 cm² and 13.4 ± 5.7 mm Hg, respectively. Two patients had moderate perivalvular leaks. At the 30-day follow-up, there were two deaths due to multisystem failure in two transapical patients. In one patient, an undersized, suboptimally positioned, unstable valve required late conversion to open surgery.

The investigators concluded that TAVI in selected high-risk patients with severe bicuspid aortic valve stenosis can be successfully performed with acceptable clinical outcomes but will require further evaluation.