Is nisoldipine capable of reducing left ventricular preload?

In ten anesthetized pigs, nisoldipine (2-4 micrograms X kg-1 X min-1), a calcium channel blocker structurally related to nifedipine, reduced left ventricular systolic pressure (40%) and systemic vascular resistance (35%), whereas maxLVdP/dt decreased by 20% and cardiac output was unchanged. Left ventricular end-diastolic volume (15%) and end-diastolic pressure (40%) decreased, while ejection fraction slightly increased (13%). In normal hearts, nisoldipine reduces left ventricular pre- and afterload, without a depression of myocardial contractility, which results in a more efficient emptying of the left ventricle.

Antiarrhythmic action and protection of ischaemia myocardium after beta-blockade with bevantolol.

In the present study 12 of 13 untreated pigs died of ventricular fibrillation during three 10 min episodes of left anterior descending coronary artery occlusion interrupted by 20 min of reperfusion. The selective beta-adrenoceptor antagonist bevantolol in a dose of 1.5 mg X kg-1, but not 0.5 mg X kg-1, offered nearly complete protection against this fatal arrhythmia. Evidence is also presented that bevantolol enhanced the recovery of regional myocardial function after these ischaemic events.

Arterial stenting with self-expandable and balloon-expandable endoprostheses.

Coronary angioplasty is complicated by acute occlusion (within 24 hours) and late restenosis (within 6 months) in 2-5% and 20-40% of the cases, respectively. Vascular endoprostheses (stents) may provide the cardiologist with a solution to some of these complications. Several stent-devices are now available for experimental and clinical evaluation. In this study we describe our experience with two metallic stents in normal arteries of swine. Self-expandable, stainless steel stents (3.5 mm diameter) were implanted in 17 peripheral arteries, eight of which were deendothelialized by prior balloon angioplasty. Following implantation, the animals received antithrombotic therapy with acenocoumarol and aspirin (8 stents), or aspirin alone (9 stents). After 1 week repeat angiography was performed, which showed patency of all stented arteries. Microscopy showed complete covering by neointima, 80 microns in thickness. This self-expandable stent (SES) and a balloon-expandable stent (BES), constructed of tantalum, were implanted in normal coronary arteries. SES (3.0 and 3.5 mm) receiving animals were treated with coumadines (10 stents) or received no antithrombotic treatment (16 stents) after implantation. BES receiving animals were also not treated (10 stents). Three untreated animals with SES died suddenly within 48 hours. Postmortem examination showed partial or complete thrombosis of all six stents in these animals, resulting in a patency rate of 62% after 1 week. All animals with SES, which were treated with coumadines, and all animals with BES (untreated) had patent stents after one week. It is concluded that SES implanted in normal coronary arteries of pigs, which do not receive additional antithrombotic treatment, show a 38% occlusion rate within 48 hours, but show 100% patency after 1 week, when the animals are treated with coumadines. BES implanted in normal coronary arteries of pigs, which do not receive antithrombotic drugs, are 100% patent after 1 week.