Intra-Aortic Balloon Counterpulsation in Patients With Chronic Heart Failure and Cardiogenic Shock: Clinical Response and Predictors of Stabilization

Abstract

Objective: The aim of this work was to characterize the clinical response and identify predictors of clinical stabilization after intra-aortic balloon counterpulsation (IABP) support in patients with chronic systolic heart failure in cardiogenic shock before implantation of a left ventricular assist device (LVAD).

Background: Limited data exist regarding the clinical response to IABP in patients with chronic heart failure in cardiogenic shock.

Methods: We identified 54 patients supported with IABP before LVAD implantation. Criteria for clinical decompensation after IABP insertion and before LVAD included the need for more advanced temporary support, initiation of mechanical ventilation or dialysis, increase in vasopressors/inotropes, refractory ventricular arrhythmias, or worsening acidosis. The absence of these indicated stabilization.

Results: Clinical decompensation after IABP occurred in 23 patients (43%). Both patients who decompensated and those who stabilized had similar hemodynamic improvements after IABP support, but patients who decompensated required more vasopressors/inotropes. Clinical decompensation after IABP was associated with worse outcomes after LVAD implantation, including a 3-fold longer intensive care unit stay and 5-fold longer time on mechanical ventilation (P < .01 for both). Although baseline characteristics were similar between groups, right and left ventricular cardiac power indexes (cardiac power index = cardiac index × mean arterial pressure/451) identified patients who were likely to stabilize (area under the receiver operating characteristic curve = 0.82).

Conclusions: Among patients with chronic systolic heart failure who develop cardiogenic shock, more than one-half of patients stabilized with IABP support as a bridge to LVAD. Baseline measures of right and left ventricular cardiac power, reflecting work performed for a given flow and pressure, may allow clinicians to identify patients with sufficient contractile reserve who will be likely to stabilize with an IABP versus those who may need more aggressive ventricular support.

Keywords: IABP; Intra-aortic balloon counterpulsation; cardiogenic shock; heart failure; left ventricular device implantation; percutaneous support.

Figure 1

Patient Selection and Study Design *See table 1 for clinical decompensation criteria. 15 patients met only 1 criterion; 4 met 2 criteria, 3 met 3 criteria and 1 met 4 criteria.

Figure 2. Hemodynamic Improvements after IABP support

(A)Left ventricular Cardiac power index and change after IABP, (B)Right ventricular cardiac power index and change after IABP, (C)Pulmonary artery systolic pressure and change after IABP, (D) Cardiac Index and change after IABP, (E) pulmonary capillary wedge pressure and change after IABP, (F) right atrial pressure and change after IABP, (G)vasoactive medication number and change after IABP, and (H)urine output and change after IABP support in those who stabilized and decompensated. Values represented as a mean with standard deviation bars shown. Minimum and maximum bars shown for the change in respective values with box plots representing the median, 25^th and 75^th percentiles. Significance for change in hemodynamic values and clinical variables was determined with a paired T test between IABP stabilized and decompensated groups. *denotes p value <0.05 for paired T test within the group (i.e. pre and post measurements for stabilized and decompensated groups). **Significance for change in vasoactive medications was determined by Mann-Whitney U test for changes between stabilized and decompensated groups and a matched samples Wilcoxon Ranked sign test for within group changes.

Figure 3. Post LVAD outcomes

(A) Intensive care unit days and (B) ventilator days post LVAD implantation for patients who stabilized or decompensated after IABP support. Ventilator and ICU days censored at death or transplantation. Univariate Mantle-Cox Log Rank test used to compare groups.

Figure 4. IABP stabilization Score

Patients received one point for a right ventricular cardiac power output ≥ 0.13 watts/m² or left ventricular cardiac power index ≥ 0.33 watts/m². Only patients with both values available prior to IABP insertion were included.