Objectives: To evaluate the feasibility of percutaneous aortic valve replacement without cardiac arrest in animal experiments. Methods: A self expanding nitinol stent, containing pulmonary valves from pigs in its proximal part, was implanted in six pigs (94-118 kg) by means of a 25 French catheter through the left subclavian artery under guidance of fluoroscopy and transoesophageal echocardiography. During stent deployment the original aortic valve was pushed against the aortic wall by the self expanding force of the stent while the new valve was expanded. Results: It was possible to replace the aortic valve in the beating heart in four pigs (67%) with no complication or relevant drop in blood pressure. The procedure failed in two pigs (33%) due to dysfunction of the catheter device in one case and to problems with correct positioning in the left ventricular outflow tract in the other. After successful stent valve implantation, dopamine was infused in doses of 5 mg/kg/min, 10 mg/kg/min, and 15 mg/kg/min. Cardiac output increased from 4.4 to 8.8 l/min and the mean arterial pressure rose from 79 to 105 mm Hg. The maximum peak to peak pressure gradient across the valve carrying stent reached a maximum of 8 mm Hg under dopamine infusion. All pigs were killed six hours after transvascular aortic valve replacement. The chest was opened, and the left ventricle and the ascending aorta were carefully inspected. There were no signs of malfunction of the implant, of damage of the aortic vessel wall, or of obstruction of the coronary ostia. Conclusions: Percutaneous aortic valve replacement with a self expanding nitinol stent in the beating heart is possible. The device was safe under pharmacological stress test. After successful chronic animal experiments, this concept may become a feasible option for treating patients with relevant aortic valve disease but where open heart surgery would be risky. P atients with a stenosis of the aortic valve do not show any symptoms for several years. But when they become symptomatic, their prognosis is limited if the valve is not replaced.1 The prevalence of severe calcification of the aortic valve is 13% in patients 75 years and older. 2 The number of elderly patients with relevant co-morbidity and symptomatic aortic valve disease is increasing. These patients are often high risk candidates for open heart surgery with a heart-lung machine.3 Recently, a one month mortality rate of nearly 24% was reported among patients 90 years and older after open heart valve surgery.4 Thus, there is need for a less invasive technique of aortic valve replacement. Several groups have been working on this field during the past decade. 5-8Bonhoeffer and colleagues 9 were the first to implant a valve percutaneously with a transvenous approach in a human. They sutured a bovine jugular vein valve within a balloon expandable stent for replacing the pulmonary valve. Cribier and colleagues 10 also used a biological valve mounted in a balloon expandable stent, which was implanted in a transseptal approach. These ...

Iatrogenic rupture of a pulmonary artery is a rare and life-threatening complication of the catheterization of the right heart and demands rapid therapy. The protection of the contralateral lung by intubation with a double-lumen tubes is of highest priority. Selective embolization of the affected vessel via thrombin can be a lifesaving alternative to lobectomy or conservative therapy.

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