Abstract 4373: Incidence and Prognostic Value of a Troponin Elevation After Transfemoral Aortic Valve Implantation
Increased cardiac troponin is observed after cardiac surgery, indicating perioperative myocardial injury, although the clinical significance of this elevation remains controversial.
Purpose: The current study was designed to evaluate the degree of troponin elevation after transcutaneous aortic valve implantation (TAVI) and to assess the prognostic value of troponin level after TAVI.
Methods: 57 consecutive patients (mean age 84±6 years old, 53% females) with severe symptomatic AS had retrograde TAVI using the Edwards-Sapien balloon expandable heart valve. 26% of patients had previous CABGs and 28% had previous coronary angioplasty. At the time of valve implantation, 30% of patients had at least one significant coronary stenosis (>50 %). Transfemoral TAVI was performed under local anesthesia and surgical cut-down. A 23 or 26 mm transcutaneous valve was implanted during a burst of rapid pacing (200 to 220 bpm) to obtain a transient reduction in transvalvular blood flow. Cardiac Troponin I (Tn I) was measured using the DPC Immulite 2500 assay (lower limit of detection: 0.2 μg/l, suggested diagnostic value for myocardial infarction: 1.0 μg/l) before, 8 hours and 24 hours after TAVI.
Results: After TAVI, effective orifice area increased from 0.64±0.15 to 1.83±0.26 cm2 (p<0.0001) and transvalvular mean gradient decreased from 46±15 to 8±4 mmHg (p<0.0001). Tn I level was 0.09±0.27 μg/l at baseline and significantly increased to 2.28±0.27 and 3.63±3.54 μg/l at 8 and 24 hours respectively after TAVI (p<0.001). Tn I level was above the suggested diagnostic value for myocardial infarction of 1.0 μg/l in 49 (86%) patients. No patients exhibited new pathological Q-waves. During a mean follow-up of 14±10.7 months, 9 (16%) patients died. A cutoff point of ≤2.70μg/l (p<0.05) elevation in Tn I level (peak minus baseline value) provided the optimal sensitivity and specificity for identifying patients at risk of death.
Conclusions: Moderate elevation in Troponin I is common after TAVI and is predictive of death during follow-up. Therefore, monitoring Troponin I within the first 24 hours after TAVI may help to stratify patients at risk of death.