Thromboaspiration Before Intra-aortic Balloon Counterpulsation

To the Editor: Dr Patel and colleagues found that the routine use of intra-aortic balloon counterpulsation (IABC) in hemodynamically stable patients with anterior ST-segment elevation myocardial infarction did not lead to a reduction in infarct size as assessed by magnetic resonance imaging.¹ I would like to suggest an alternate hypothesis not mentioned in the discussion with implications for future study design.

In reviewing this report, I was struck by the relatively low rate of mechanical thromboaspiration. In the Thrombus Aspiration during Percutaneous Coronary Intervention in Acute Myocardial Infarction Study, myocardial blush grade was improved and mortality was lower to 1 year with mechanical thrombectomy.^{2 - 3} Sardella et al⁴ demonstrated in a randomized trial that mechanical thromboaspiration resulted in reduction in major adverse cardiac events and cardiac mortality at 24 months compared with percutaneous coronary intervention (PCI) without thromboaspiration. This same group also reported a reduction in infarct size in patients treated with mechanical thromboaspiration,⁵ which likely explains the survival benefit.

While the rates of thromboaspiration were similar in the 2 groups in the study by Patel et al,¹ it is possible that the nonuse of thromboaspiration as the initial PCI device in the majority of patients (63.8%) could have resulted in sufficiently high rates of distal embolization to interfere with any potential benefit of IABC in terms of infarct size reduction. Although the rate of thromboaspiration in this study likely represents actual clinical practice across participating and nonparticipating centers, I suggest that future studies should encourage the use of mechanical thromboaspiration prior to balloon angioplasty or stent placement to determine if there are any benefits from IABC or other methods of mechanical support in high-risk patients.