**9. Valve equipped Biomechanical Hearts**

Valve-less BMHs offered an additional pulmonary flow of 113± 37 ml/min resp. 5.4±1.8%, those with one distal valve offered 304±126 ml/min resp. 14.5±6%. BMHs equipped with two valves increased the pulmonary blood flow by 1235± 526 ml/min resp. 58±25 % (p<0.05), the mean aortic pressure in this setting raised to 19±9 mmHg (p<0.05) and the coronary flow velocity to 59±18 mm/sec (p<0.05). Corresponding reduction of left ventricle's end-diastolic pressure ranged from 31 to 17 mmHg (p<0.05), while the myocardial dp/dt increased by 470±192 mmHg/

**Figure 18.** PV- loops from a conductance catheter placed in the left heart ventriclea cavum, without (A) and with an activated (B) double-valved BMH-model as shown in Figure16. It works ECG-triggered in a 1:2 mode with a balloon inflation of 60ml helium gas. The area within a loop represents the left heart ventricles stroke work. During activation of the BMH-model the stroke work of the failing heart ventricle is increased (B) and the end-diastolic pressure (LVEDP)

The use of two valves in BMHs is essential for a relevant circulatory support. Unloading and contractility of the left heart ventricle were thus improved significantly. Two-valves-BMHs driven by a sufficient skeletal muscle ventricle may contribute to the therapy of a failing

s resp. 145±48 % (p<0.05).

356 Regenerative Medicine and Tissue Engineering

drops from 28 to 14 mmHg [12].

myocardium.

As demonstrated above, efficacy of BMHs on the circulation is dependent on the integration of two heart valve prostheses into the in- and outflow part of the pumping chamber. Valve equipped Biomechanical Hearts were constructed and integrated within circulation in adult Boer goat (n=5), and pharmacological stimulation with the β-2-stimulator Clenbuterol. (5X150μg/wk). This pumping chamber, made of PTFE, was anastomosed to the descending aorta by two ring armoured PTFE-prostheses (Impra Medica GmbH, München). Between these prostheses two porcine glutaraldehyde fixed valve bearing porcine aortic conduits were integrated like shown in Figure 20.

**Figure 20.** Scheme of an experimental setting from a valve equipped Biomechanical Heart in a big animal model (Boer goats) in an aorto-aortic configuration. The thoracic aorta is ligated between the two anastomoses. Two porcine glu‐ taraldehyde fixed valve bearing porcine aortic conduits were integrated between the connecting PTFE prostheses and the PTFE pump ventricle.

**Figure 21.** Operative situs of a BMH before transferring it into the cavity of the thorax, with four strings to fix it via the thoracic wall to the inner thoracic surface. Two stimulation electrodes and an artificial muscle tendon made of Dacron for a re-fixation onto the external thoracic wall are visible.

Skeletal Muscle Ventricles (SMVs) and Biomechanical Hearts (BMHs) with a Self Endothelializing Titanized… http://dx.doi.org/10.5772/55993 359

**Figure 22.** Intraoperative testing of the function of a valve equipped BMH by visualization of burst stimulation within the ECG, a 1:2 support within the arterial pressure curve and the flow curve which was obtained by a flow probe around the distal biologic aortic conduit

**Figure 20.** Scheme of an experimental setting from a valve equipped Biomechanical Heart in a big animal model (Boer goats) in an aorto-aortic configuration. The thoracic aorta is ligated between the two anastomoses. Two porcine glu‐ taraldehyde fixed valve bearing porcine aortic conduits were integrated between the connecting PTFE prostheses and

**Figure 21.** Operative situs of a BMH before transferring it into the cavity of the thorax, with four strings to fix it via the thoracic wall to the inner thoracic surface. Two stimulation electrodes and an artificial muscle tendon made of Dacron

for a re-fixation onto the external thoracic wall are visible.

the PTFE pump ventricle.

358 Regenerative Medicine and Tissue Engineering


**Table 1.** Intra- and post-operative data of six experimental valve equipped BMHs in adult Boer Goats
