Impact of Impella® on Dissected Coronary Artery Hemodynamics

Kiyotake Ishikawa, MD, recently published a paper that will help us understand the potential role for Impella® support in patients with coronary dissection. Dr. Ishikawa is a cardiologist at Mt. Sinai in New York and his paper is titled “Novel Porcine Model of Coronary Dissection Reveals the Impact of Impella on Dissected Coronary Arterial Hemodynamics.”

Dr. Ishikawa explains that he and his colleagues undertook this research to better understand how the Impella heart pump influences coronary physiology and left ventricular hemodynamics in the setting of iatrogenic coronary artery dissection. While this experiment was done in pigs, the researchers attempted to mimic the clinical setting as much as possible. Dr. Ishikawa describes how the team created the coronary artery dissections and intimal flaps in the left anterior descending artery (LAD) of the pigs.

Dr. Ishikawa explains that once the Impella CP® is inserted and turned on, it draws blood from the left ventricle into the aorta, increasing aortic and arterial pressure. This increase in coronary arterial pressure was seen in the distal coronary arteries in 7 of the 8 pigs studied. In 1 pig however, there was a decrease in coronary artery pressure even though there was an increase in aortic pressure. This was found to be due to obstruction caused by the flap from the coronary artery dissection. Thus, results from the 7 pigs showed that ischemia improved with unloading from Impella, yet there was exacerbation of the occlusion with Impella support in the pig with the occlusive flap.

Dr. Ishikawa discusses the hemodynamic traces shown in Figure 4 of his paper, illustrating that when Impella support was initiated with non-flow-limiting coronary dissection, left ventricular volume decreased, coronary mean pressure increased, and diastolic aortic pressure increased consistently. He discusses the effect of Impella on left ventricular parameters after coronary dissection described in Table 2, noting, “this all indicates the unloading of the left ventricle, which should alleviate ischemia.” He then reviews Figure 5 from the paper, which shows hemodynamics from the pig with the occlusive flap and he explains that coronary pressure decreased rather than increased, suggesting worsening of obstruction when Impella was turned on.

Dr. Ishikawa concludes that Impella is able unload the left ventricle even in cases of impaired coronary flow, and it increases coronary perfusion pressure and is probably beneficial for most cases, although clinicians need to be aware that exaggerated flap obstruction can worsen antegrade flow.