09 Jan 10

Intra-aortic balloon counterpulsation in patients with acute myocardial infarction complicated by cardiogenic shock

Posted in Heart failure/Cardiogenic shock, IABP at 0:44 by Laci

By R Prondzinsky, H Lemm, M Swyter, N Wegener, S Unverzagt et al

Crit Care Med 2010;38:152-160

Patients undergoing percutaneous coronary intervention (PCI) for acute myocardial infarction with cardiogenic shock (CS) are often treated with intra-aortic balloon pump counterpulsation (IABP), even though the evidence to support this is limited. We determined whether IABP as an addition to PCI-centered therapy ameliorates multiorgan dysfunction syndrome (MODS) in patients with acute myocardial infarction complicated by CS.

Design
A prospective, randomized, controlled, open-label clinical trial recruiting patients between March 2003 and June 2004

Setting
Intra-aortic balloon counterpulsation in patients with acute myocardial infarction complicated by cardiogenic shock: The prospective, randomized IABP SHOCK Trial for attenuation of multiorgan dysfunction syndromeTertiary care university hospital.

Patients and interventions
Forty-five consecutive patients with AMI and CS undergoing PCI were randomized to treatment with or without IABP.

Measurements and main results
Acute Physiology and Chronic Health Evaluation (APACHE) II scores (primary outcome measure), hemodynamic values, inflammatory markers, and plasma brain natriuretic peptide (BNP) levels (secondary outcomes) were collected over 4 days from randomization. The prospective hypothesis was that adding IABP therapy to “standard care” would improve CS-triggered MODS. The addition of IABP to standard therapy did not result in a significant improvement in MODS (measured by serial APACHE II scoring over 4 days). IABP use had no significant effect on cardiac index or systemic inflammatory activation, although BNP levels were significantly lower in IABP-treated patients. Initial and serial APACHE II scoring correlated with mortality better than cardiac index, systemic inflammatory state, and BNP levels in this group of patients. Nonsurvivors had significantly higher initial APACHE II scores (29.9 ± 2.88) than survivors (18.1 ± 1.66, p < .05). Nevertheless, discrepancies among patients within the groups cannot be ruled out and might interfere with our results.

Conclusions
In this randomized trial addressing addition of IABP in CS patients, mechanical support was associated only with modest effects on reduction of APACHE II score as a marker of severity of disease, improvement of cardiac index, reduction of inflammatory state, or reduction of BNP biomarker status compared with medical therapy alone. However, the limitations of our present trial preclude any definitive conclusion, but request for a larger prospective, randomized, multicentered trial with mortality as primary end point.

12 Jan 09

Effects of intra-aortic balloon counterpulsation in a model of septic shock

Posted in IABP, Inotropic support, Sepsis at 0:05 by Laci

By SB Solomon, PC Minneci, KJ Deans, J Feng, PQ Eichacker, SM Banks, RL Danner, C Natanson and MA Solomon

Critical Care Med 2008;37:7-18

Fluid refractory septic shock can develop into a hypodynamic cardiovascular state in both children and adults. Despite management of these patients with empirical inotropic therapy (with or without a vasodilator), mortality remains high.

Objectives
The effect of cardiovascular support using intra-aortic balloon counterpulsation was investigated in a hypodynamic, mechanically ventilated canine sepsis model in which cardiovascular and pulmonary support were titrated based on treatment protocols.

Methods
Each week, three animals (n = 33, 10-12 kg) were administered intrabronchial Staphylococcus aureus challenge and then randomized to receive intra-aortic balloon counterpulsation for 68 hrs or no intra-aortic balloon counterpulsation (control). Bacterial doses were increased over the study (4-8 x 109 cfu/kg) to assess the effects of intra-aortic balloon counterpulsation during sepsis with increasing risk of death.

Main results
Compared with lower bacterial doses (4-7 x 109 colony-forming units/kg), control animals challenged with the highest dose (8 x 109 colony-forming units/kg) had a greater risk of death (mortality rate 86% vs. 17%), with worse lung injury ([A – a]o2), and renal dysfunction (creatinine). These sicker animals required higher norepinephrine infusion rates to maintain blood pressure (and higher Fio2) and positive end-expiratory pressure levels to maintain oxygenation (p <= 0.04 for all). In animals receiving the highest bacterial dose, intra-aortic balloon counterpulsation improved survival time (23.4 +/- 10 hrs longer; p = 0.003) and lowered norepinephrine requirements (0.43 +/- 0.17 [mu]g/kg/min; p = 0.002) and systemic vascular resistance index (1.44 +/- 0.57 dynes/s/cm5/kg; p = 0.0001) compared with controls. Despite these beneficial effects, intra-aortic balloon counterpulsation was associated with an increase in blood urea nitrogen (p = 0.002) and creatinine (p = 0.12). In animals receiving lower doses of bacteria, intra-aortic balloon counterpulsation had no significant effects on survival or renal function.

Conclusions
In a canine model of severe septic shock with a low cardiac index, intra-aortic balloon counterpulsation prolongs survival time and lowers vasopressor requirements.

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