The Research On Direct Mechanical Ventricular Actuation For The Acute Canine Heart Failure Model

ObjectiveThis paper aims to design the New Direct Mechanical Ventricular Actuation(DMVA)and test the new device on acute canine heart failure model.The new device was used for acute heart failure in dogs, to observe the effect on their systolic and diastolic function, hemodynamic, heart function and myocardial injury.Therefore,the research provide an important foundation for the study of the impact of chronic heart failure in canine. Method1.Design of Direct Mechanical Ventricular Actuation. To design a new type of direct mechanical ventricular actuation(DMVA), which consists of two inflatable silicone patch elements bio-integrated to the left and right ventricular epicardium.Each patch has a heart contacting(visceral) membrance that is more distensible than outer(parietal) wall that fixed on the Spiral-shaped appearance,with the two enclosing an air chamber.Inflation and deflation of the patches are driven by the IABP with synchronized with the cardiac cycle,inflating systolic and deflating diastolic to improve systolic and diastolic function. 2. The establishment of acute heart failure model. Sixteen heart failure dogs were established by ligation of the left anterior descending coronary artery distant to first diagonal branch method, and then were observed cardiac output changes(reduced cardiac output greater than 30%).The canine were divided into two groups by random number table method.Group A consisted of heart failure dogs with DMVA aiding. Group B was the control group, given directly implanted DMVA, but not open auxiliary functions. At the start of the experiment, the two groups are using biventricular assist and using 1: 1 assist auxiliary frequency(1: 1, that is the heart beat once with the DMVA systole once).The cardiac output(CO), aortic pressure,and other hemodynamic parameters were recorded and these data were statistically analyzed. Three major serum cytokines including Tumor necrosis factor(TNF-α)、Interleukin-1(IL-1) and Interleukin-6(IL-6)in blood were observed through the blood samples taken after failure, and after auxiliary 60 min,180min,360 min respectively. At the end of the experiment myocardial tissue pathology testing was performed to observe inflammation and cell structure through cutting apical myocardial tissue. ResultsTwo sudden death canine died from malignant arrhythmias, the others fourteen dogs reached to acute heart failure model standards. With the assisting 180 min of the DMVA for acute heart failure canine, cardiac output、blood pressure and other hemodynamic parameters were significantly improved. Cardiac output increased by 31.0%,from baseline(1.6 ± 0.3) L / min to(2.5 ± 0.35) L / min. Aortic systolic pressure after assisted increased by 29.7%,from(92.0 ± 8.0) mm Hg to(135.0 ± 7.5) mm Hg. Aortic diastolic pressure with the aid of DMVA was improved from(58.0 ± 4.0) mm Hg to(64.0 ± 5.0) mm Hg. Mean aortic pressure with the aid of DMVA was improved 27.2%,from(70.0 ± 6.0) mm Hg to(101.80 ± 7.0) mm Hg. There was little change in heart rate [(123.0 ± 8.0) beats / min ratio(126.0 ± 10.0) beats / min] with the DMVA, the difference was not statistically significant(P> 0.05).The differences in hemodynamic parameters(cardiac output, mean arterial pressure) were statistically significant(P <0.01).After aid 60 min,180min,360 min respectively, with the aid of DMVA, the serum TNF-α content was decreased than the Group B, and the increasing trend of the IL-1 was reduced with the aid of prolonged.The serum TNF-α content between the two groups in 180 min, 360 min point difference were statistical significance(P<0.05); after aid 60 min,180min,360 min, the content of serum IL-1 was significantly lower than the Group B, and the increasing trend of the IL-1 was reduced with the aid of prolonged.The serum IL-1 content between the two groups in 60 min,180min,360 min point difference were statistical significance(P<0.05); after using the DMVA for A group in 60 min,180min,360 min point, the content of serum IL-6 was significantly lower than the B group, and the increasing trend of the IL-6 was reduced with the aid of prolonged. The serum IL-6 content between the two groups in 60 min,180min, 360 min point difference were statistical significance(P<0.05). Conclusion1. In acute heart failure dogs with the aid of DMVA group, assisting systolic and diastolic of the heart,cardiac output, aortic pressure and hemodynamic parameters in dogs has been significantly improved.2. By the use of the DMVA in heart failure dogs,the content of serum TNF-α, IL-1and IL-6 was significantly lower than the B group, and the increasing trend of the three major serum cytokines was reduced with the aid of prolonged.3. the DMVA can increase tissue perfusion and improve heart function. Through the DMVA,the myocardial cell ultrastructure tends to return to normal.