Increase in coronary blood flow by intra-aortic balloon counterpulsation in a porcine model of myocardial reperfusion
3rd Department of Cardiology, University of Athens School of Medicine, Athens, Greece. International journal of cardiology
(Impact Factor: 4.04).
09/2008; 138(3):253-60. DOI: 10.1016/j.ijcard.2008.08.015
Studies of the IABP have reported variable effects on coronary blood flow (CBF). The purpose of the present study was to measure the changes in coronary blood flow induced by intra-aortic balloon pump (IABP) counterpulsation in normal and reperfused porcine myocardium.
A 30-ml IABP was placed in the descending aorta of 6 open-chest pigs. Each pig underwent occlusion of the mid-left anterior descending (LAD) coronary artery for 1 h, followed by reperfusion for 2 h. The effects of IABP support on systolic aortic pressure (SAP) and aortic end-diastolic pressure were recorded. The mean CBF, distal to the LAD occlusion site was measured at baseline and during reperfusion, with and without IABP counterpulsation.
The IABP decreased SAP and aortic end-diastolic pressure in normal and reperfused myocardium, and maintained a peak aortic diastolic augmentation at the level of SAP. In normal myocardium, the IABP decreased mean CBF by 8.4+/-2.2% (p<0.001). At 2, 15, 30, 60, 90 and 120 min of reperfusion, the IABP increased mean CBF by 11.5+/-6.8%, 8.0+/-7.0%, 11.2+/-6.9%, 12.4+/-12.9%, 23.5+/-9.9% and 8.9+/-6.9%, of the corresponding value without the assistance of the IABP (all p<0.05).
In the normal heart, IABP counterpulsation decreased CBF, probably because of a decrease in myocardial oxygen demand from a decreased afterload. During reperfusion the IABP increased CBF, suggesting that it might effectively mitigate the no-reflow phenomenon.
Available from: Filippo Crea
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ABSTRACT: No-reflow phenomenon occurs frequently during primary percutaneous coronary intervention for ST-segment elevation myocardial infarction and it has a strong negative impact on outcome. Prevention of no-reflow has to be defined as any attempt to prevent its occurrence prior to or during the recanalization procedure. Strategy of prevention may be pharmacological or device based. Among drugs, abciximab is indicated by European Society of Cardiology (ESC) guidelines for prevention of no-reflow (class of recommendation IIa and level of evidence B). Among devices used for preventing no-reflow, manual thrombus aspiration only has been associated with a reduction of no-reflow and lower mortality at follow-up and is currently indicated in the ESC guidelines (class IIa of recommendation and level B of evidence). Treatment of no-reflow has to be defined as any attempt to treat its occurrence after coronary recanalization. Strategy of treatment may be pharmacological or device based. Adenosine and verapamil are indicated by ESC guidelines for treatment of no-reflow (class of recommendation IIb and level of evidence B and C, respectively). Serial assessment of myocardial perfusion showed that in up to 50% of patients no-reflow is spontaneously reversible. This finding may open new scenarios, as mechanisms of reversibility may become future therapeutic targets.
Available from: Antonino S Rubino
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ABSTRACT: The evaluation of the impact of intraaortic balloon pump (IABP) on postischemic coronary perfusion and myocardial contractile impairment has been so far limited to early reperfusion phase. Therefore, we analyzed the 24-hour effects of IABP on coronary blood flow (CBF) and left ventricular performance in an animal model of acute myocardial ischemia-reperfusion injury. Healthy swine (n = 20) underwent 120-minute ligation of the left anterior descending coronary artery followed by 24 hours of reperfusion. We randomly assigned the animals to have IABP placed in the descending aorta 5 minutes after reperfusion onset (n = 10) or to undergo no implantation (n = 10). We measured CBF, coronary resistance, cardiac cycle efficiency (CCE), and maximal pressure/time ratio before ischemia was induced and at 30 minutes and 1, 6, 12, and 24 hours after reperfusion began. During diastole, CBF was significantly increased in IABP compared with baseline and controls at all time points (all p < 0.001). This was also true during systole in IABP only for the first hour after reperfusion began. Additionally, both CCE and pressure/time ratio were significantly increased in IABP compared with baseline at 30 minutes and 1 hour after reperfusion began (p < 0.001). IABP was associated with enhanced CBF and cardiac efficiency in a model of acute ischemic-reperfusion injury.
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ABSTRACT: This Review explores contemporary circulatory support in profound postinfarction cardiogenic shock. Frequently, death is the only alternative to implantation of a blood pump, so prospective randomized trials of device versus medical treatment are unacceptable and evidence is derived from clinical experience. Irrespective of ACC/AHA and European guidelines, no study has shown survival benefit for the intra-aortic balloon pump in patients with established shock. In the past 10 years, the safety and durability of mechanical blood pumps has improved considerably. New temporary and long-term rotary pumps have transformed outcomes for patients with acute heart failure. For urgent resuscitation, outreach salvage, and transportation extracorporeal membrane oxygenation (ECMO) is a reliable, but time limited, first step. ECMO decompresses the venous system, provides flow, and ensures oxygenation, but does not unload the failing left ventricle. Myocardial stunning takes days, and sometimes weeks, to recover. Effective ventricular unloading is best achieved by surgical implantation of a temporary rotary or volume-displacement pump. After cardiopulmonary resuscitation, hemodynamic stabilization allows assessment of cerebral injury and prognosis. Published series demonstrate that 50-75% of patients with profound shock can be salvaged either through native heart recovery, urgent transplantation, or switch to a long-term pump.
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