Improved regional myocardial blood flow, left ventricular unloading, and infarct salvage using an axial-flow, transvalvular left ventricular assist device. A comparison with intra-aortic balloon counterpulsation and reperfusion alone in a canine infarction model.

Abstract

Background. It has been suggested that left ventricular unloading at the time of reperfusion provides superior infarct salvage over reperfusion alone. The purpose of this study was to show that the Hemopump transvalvular axial-flow left ventricular assist device provides superior left ventricular unloading, ischemic zone collateral blood flow, and infarct size reduction compared with intra-aortic balloon counterpulsation and reperfusion alone.Methods and Results. Eighteen dogs were instrumented with regional myocardial function sonomicrometers in the ischemic and control zones. The left anterior descending coronary artery just distal to the first diagonal branch was instrumented with a silk snare and Doppler flow probe. Additionally, pressure catheters were placed in the left atrial appendage, left ventricular apex, and ascending aorta for hemodynamic measurements. Regional myocardial blood flow was determined by using 15 -gm radioactive microspheres. Measurements were made in the control state, immediately after coronary occlusion, at 1 and 2 hours after coronary occlusion, with reperfusion, and 1 hour after reperfusion. In treated animals, left ventricular assistance was maintained during the entire period of occlusion and reperfusion. The Hemopump was associated with a significant decrease in left ventricular systolic and diastolic pressure, whereas mean arterial pressure was maintained. Intra-aortic balloon counterpulsation resulted in no significant changes in left ventricular systolic pressure and a modest decrease in left ventricular diastolic pressure. Regional unloading as assessed by sonomicrometers was significant in the Hemopump animals and absent in the balloon pump animals. Absolute regional myocardial blood flow in the ischemic zone increased slightly (p=0.002) in the Hemopump animals and did not change in the balloon pump animals. Infarct size expressed as percentage of the zone at risk was 62.6% in the control animals, 27.22% in the balloon pump animals, and 21.7% in the Hemopump animals.Conclusions. Mechanical unloading of the ventricle during ischemia and reperfusion appears to result in significant infarct salvage compared with reperfusion alone. The Hemopump appears to provide superior left ventricular systolic and diastolic unloading compared with intra-aortic counterpulsation in

2015 SCAI/ACC/HFSA/STS clinical expert consensus statement on the use of percutaneous mechanical circulatory support devices in cardiovascular care (Endorsed by the American heart assocation, the cardiological society of India, and sociedad latino Americana de cardiologia intervencion; Affirmation of value by the canadian association of interventional cardiology–association canadienne de cardiologie d'intervention)

“…Ventricular unloading may reduce myocardial infarct size through enhanced hemodynamics, preserved energetics, and activation of cardioprotective mechanisms [48,116]. Despite limited unloading potency, some animal infarct model studies found improved myocyte recovery with IABP use [117,118]. However, as described above, the CRISP-AMI study [101] found no difference in mean final infarct size between STEMI patients (not complicated by cardiogenic shock) who received routine IABP compared with those who did not.…”

Change of Coronary Flow by Continuous-Flow Left Ventricular Assist Device With Cardiac Beat Synchronizing System (Native Heart Load Control System) in Acute Ischemic Heart Failure Model

“…Thus, many researchers have discussed the effect of LVADs on myocardial perfusion, but it remains incompletely understood. [43][44][45][46][47] A counter-pulse effect may be useful for increasing coronary perfusion with increasing aortic pressure in the diastolic phase. 44, [48][49][50] Therefore, in the present study we focused on CoF, which we expected to control with the cf-LVAD using the pulsatile driving technique.…”

Effects of Intraaortic Balloon Pumping on the Angiographic No-Reflow Phenomenon After Percutaneous Coronary Intervention in Patients With Anterior Myocardial Infarction

“…19 However, recent studies that have measured coronary flow velocity directly using a Doppler catheter, 2 Doppler guide wire, 3 transesophageal echocardiography 20 or transthoracic echocardiography 6 also reported different effects of IABP on coronary flow, namely that it increased 2,6 or remained unchanged. 3,7 Some investigators 3,5 have suggested that the inconsistency in the coronary flow velocity response during IABP may be related to differences in the severity of the coronary artery stenoses. Kern et al 4 found that IABP augmentation increased the proximal coronary flow velocity, as measured by a Doppler catheter, 4 and they also reported that coronary flow velocity was unaffected by IABP augmentation in the presence of severe coronary artery stenosis.…”

“…Although the former effect is well recognized, the latter effect remains controversial, 2-6 because previous studies have reported that coronary blood flow during IABP either increased 2,6 or remained unchanged. 3,7 Percutaneous coronary intervention (PCI) is used as a treatment for acute myocardial infarction (AMI), and one of its major complications is the angiographic no-reflow phenomenon. Once this phenomenon occurs, the prognosis is extremely poor.…”