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Transcatheter aortic valve replacement (TAVR) typically produces at least some degree of myocardial injury, with higher levels associated with acute kidney injury (AKI), according to a small study published online February 27, 2013, ahead of print in the American Journal of Cardiology. However, only AKI was found predictive of 1-year mortality.
Nazario Carrabba, MD, of Careggi Hospital (Florence, Italy), and colleagues looked at 62 patients with severe aortic stenosis who underwent TAVR with the CoreValve prosthesis (Medtronic, Minneapolis, MN). Levels of cardiac troponin I, CK-MB, and creatine were measured at 6 hours and several time points up to 72 hours.
AKI Is the Telling Complication
All patients were found to have myocardial injury. A higher degree of such injury was observed in the 9 patients (14.5%) who also developed AKI, as defined by Valve Academic Research Consortium criteria. There were no instances of periprocedural MI.
Multivariate analysis found that AKI was the only independent predictor of 1-year mortality from any cause including heart failure (table 1).
Table 1. Multivariate Predictors of Cumulative Mortality and Heart Failure
Peak Cardiac Troponin I
At 1 year, 5 patients (8.1%) died (3 of renal failure, and 1 each of stroke and heart failure), all in the AKI group, while 7 (11.3%) had been hospitalized for heart failure. Freedom from events was lower in patients with AKI compared with those without the condition (P < 0.0001).
Minimizing Hypotension Key
“The present study highlights the clinical relevance of assessing kidney function within 72 hours of [TAVR] to identify patients who complicate with AKI and thereby require more efficient management (continuous hydration, ultrafiltration, hemodialysis) during the postprocedural period,” Dr. Carrabba and colleagues write.
From a preventive standpoint, the authors recommend reducing the number of rapid pacing runs, since short periods of severe hypotension may play a role in the deterioration of renal function after TAVR. In addition, they say, “the occurrence of severe hypotension during balloon and valve expansion as well as any complication leading to severe hypotension should be avoided through the continuous control and optimization of hemodynamic support.”
The investigators outline several study limitations, acknowledging that the possibility that “preexisting renal insufficiency may contribute to adverse outcomes” in TAVR patients cannot be completely excluded.
A transfemoral approach was used in all but 3 patients, each of whom underwent a subclavian approach.
Myocardial injury was defined as a cardiac troponin I level greater than 0.15 µg/L or a CK-MB level greater than 3.6 µg/L.
At baseline, patients who developed AKI after TAVR were older (P = 0.033) and showed a trend toward higher logistic EuroSCORE (P = 0.058). All patients received aspirin (100-325 mg/day) and clopidogrel (600-mg loading dose, then 75 mg/day) before TAVR and aspirin alone after 3 months of dual therapy.