Muscular Counterpulsation: Preliminary Results of a Non-Invasive Alternative to Intra-Aortic Balloon Pump
Objectives: IABP is the most widely used form of temporary cardiac assist and its benefits are well established. We designed an animal study to evaluate a device based on muscular counterpulsation (MCP) that should reproduce the same hemodynamic effects as IABP in a completely non-invasive way.
Methods: Six calves, 60±4 kg, divided into 2 groups, in general anaesthesia, equipped with EKG, Swan-Ganz, pressure probe in the femoral artery and flow probe in the left carotid artery, received either IABP through right femoral artery, or muscle counterpulsation (MCP). MCP consists of electrically induced skeletal muscle contraction during early diastole, triggered by EKG and microprocessor controlled by a portable device. For each animal the following parameters were also considered: mean aortic pressure (mAoP), CO, CI, left ventricular stroke work index (LVSWI), systemic vascular resistance (SVR) and mean femoral artery flow (Faf). We did 3 sets of measurements: baseline (BL), after 20 (M20) and 40 (M40) min of cardiac assistance. These measurements have been repeated after 40 min of rest for 3 times. Results are expressed as mean±SD.
Results: Baseline values: mAoP, 76.51±12 mmHg; mCVP, 11.5±3 mmHg; CO, 5±1 l/min per m2; LVSWI, 0.77±0.2 KJ/m2; SVR, 1040±15 dyn s/cm–5; Faf, 75.5±10 ml/min. IABP group: mAoP, 81.1±6 mmHg; mCVP, 1±0.1 mmHg; CO, 4.5±0.7 l/min per m2; LVSWI, 0.69±0.2 KJ/m2; SVR, 1424±8 dyn s/cm–5; Faf, 64.3±3 ml/min. MCP group: mAoP, 60.1±7 mmHg; mCVP, 23.6±2 mmHg; CO, 4.8±0.4 l/min per m2; LVSWI, 0.69±0.2 KJ/m2; SVR, 608±25 dyns/cm–5; Faf, 92.3±12 ml/min.
Conclusions: MCP and IABP had the same effects on CO and LVSWI. Moreover, MCP reduced SVR and increased the peripheral circulation without requiring any vascular access nor anticoagulation therapy.
