title: Passive aortic counterpulsation: biomechanical rationale and bench validation.
abstract: Aortic counterpulsation (IABP) consists in an ECG-controlled forced deflation and inflation of a balloon positioned in the aorta. The device is designed to decrease the ventricular afterload during systole and to increase the coronary driving pressure during diastole. In biomechanical terms, the IABP improves the mechanical matching between the pump and the load, facilitating the transfer of ventricular energy. This paper describes a completely passive aortic counterpulsation solution, with an intra-aortic balloon without a pumping system, designed to improve the mechanical matching between the ventricle and the artery at very low cost and complexity. The only requirement is an external reservoir to amplify the balloon pulsations due to physiologic arterial pressure pulse. Using a cardiovascular simulator and changing the reservoir pressure, a systolic not negligible (7.8ml) gas volume exchange between the intra-aortic balloon and the reservoir was measured. The same cardiovascular simulator was used to demonstrate an increase in stroke volume in three conditions of progressive ventricular failure, by detecting a change in systolic and diastolic arterial pressures and stroke volume (SV). The maximal arterial pressure always decreased and the diastolic pressure increased. The SV increased up to 7.8%, demonstrating an arterial elastance reduction and better ventricular-aortic mechanical matching and energy transfer.
authors.affiliation: Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy. Electronic address: ivan.corazza@unibo.it.
authors.forename: Ivan
authors.initials: I
authors.lastname: Corazza
authors.affiliation: Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy.
authors.forename: David
authors.initials: D
authors.lastname: Bianchini
authors.affiliation: Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Marcelli
authors.affiliation: Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Cercenelli
authors.affiliation: Experimental, Diagnostic and Specialty Medicine Department, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy.
authors.forename: Romano
authors.initials: R
authors.lastname: Zannoli
mesh_terms: D001011:Aorta / Q000502:physiology* / Q000601:surgery*; D001696:Biomechanical Phenomena; D001794:Blood Pressure; D003971:Diastole; D006801:Humans; D007423:Intra-Aortic Balloon Pumping; D013318:Stroke Volume; D013599:Systole
keywords: Aortoventricular matching; IABP; VAD; Ventricular elastance