Diagnostic ultrasound combined with glycoprotein IIb/IIIa-targeted microbubbles improves microvascular recovery after acute coronary thrombotic occlusions.
BACKGROUND
The high mechanical index (MI) impulses from a diagnostic ultrasound transducer may be a method of recanalizing acutely thrombosed vessels if the impulses are applied only when microbubbles are channeling through the thrombus.


RESULTS
In 45 pigs with acute left anterior descending thrombotic occlusions, a low-MI pulse sequence scheme (contrast pulse sequencing) was used to image the myocardium and guide the delivery of high-MI (1.9 MI) impulses during infusion of either intravenous platelet-targeted microbubbles or nontargeted microbubbles. A third group received no diagnostic ultrasound and microbubbles. All groups received half-dose recombinant prourokinase, heparin, and aspirin. Contrast pulse sequencing examined replenishment of contrast within the central portion of the risk area and guided the application of high-MI impulses. Angiographic recanalization rates, resolution of ST-segment elevation on ECG, and wall thickening were analyzed. Pigs receiving platelet-targeted microbubbles had more rapid replenishment of the central portion of the risk area (80% versus 40% for nontargeted microbubbles; P=0.03) and higher epicardial recanalization rates (53% versus 7% for prourokinase alone; P=0.01). Replenishment of contrast within the risk area (whether with platelet-targeted microbubbles or nontargeted microbubbles) was associated with both higher recanalization rates and even higher rates of ST-segment resolution (82% versus 21% for prourokinase alone; P=0.006). ST-segment resolution occurred in 6 pigs (40%) treated with microbubbles who did not have epicardial recanalization, of which 5 had recovery of wall thickening.


CONCLUSIONS
Intravenous platelet-targeted microbubbles combined with brief high-MI diagnostic ultrasound impulses guided by contrast pulse sequencing improve both epicardial recanalization rates and microvascular recovery.
Xie
Feng
F
Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE 68198-2265, USA. fxie@unmc.edu
Lof
John
J
Matsunaga
Terry
T
Zutshi
Reena
R
Porter
Thomas R
TR
D000818:Animals; D003131:Combined Modality Therapy; D017023:Coronary Angiography; D003328:Coronary Thrombosis / Q000000981:diagnostic imaging / Q000628:therapy*; D004562:Electrocardiography; D006439:Hemodynamics; D045423:Microbubbles; D008833:Microcirculation; D015425:Myocardial Reperfusion / Q000295:instrumentation / Q000379:methods*; D009206:Myocardium / Q000473:pathology; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors*; D011897:Random Allocation; D011994:Recombinant Proteins / Q000627:therapeutic use; D034421:Sus scrofa; D014464:Ultrasonic Therapy / Q000295:instrumentation / Q000379:methods*; D014463:Ultrasonography; D014568:Urokinase-Type Plasminogen Activator / Q000627:therapeutic use
D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D011994:Recombinant Proteins; D014568:Urokinase-Type Plasminogen Activator; C067551:saruplase