[Risk of hypertension after heart transplantation in the follow-up period]

From October 1988 to March 2000, 58 patients underwent orthotopic heart transplantation (HTX). Data of 220 heart recipients with the follow up > or = 3 months after HTX were analyzed using the average values of blood pressure measured with the sphigmo-manometer. 65% of patients were diagnosed with the hypertension (HA). 39.9% of those patients (NTA group) had the systolic blood pressure < or = 140 mmHg and diastolic blood pressure < or = 90 mmHg during pharmacotherapy. 60.1% of hypertensive patients (NTB group) had the systolic pressure > 140 mmHg and/or diastolic pressure > 90 mmHg despite pharmacotherapy. 35% of all patients had normal blood pressure after HTX (HNA group). Patients with hypertension were older and the end stage ischemic cardiomyopathy was more frequently indication for HTX. Significantly more females were in NTA group. We observed no influence of the daily dose of cyclosporine or other immunosuppressive drugs on HA. The average blood concentration of cyclosporine A and mycophenolate mofetil was similar in all groups. The calcium channel blockers and inhibitors of angiotensin converting enzyme were main tool of pharmacotherapy used. In NTA group calcium channels blockers were used more frequently. In NTB group there was a statistically significant higher blood level of creatinine. After HTX there is a high risk of HA, which: increases with age, with the ischemic cardiomyopathy as indication to HTX, is significantly higher in males, there is no correlation between HA and the dosage and blood level of cyclosporine, increases with kidney insufficiency. In monotherapy calcium channel blockers seem to be especially effective.

Ischemic and reperfusive release of the endogenous purines and its influence on the myocardial viability during beta-adrenergic blockade

The aim of this study was to estimate ischemic and reperfusive release of myocardial adenosine degradation products (MADP) during beta-adrenergic blockade and its relation to infarct size (IS) and viable myocardium size (VM). In a group of 24 shepherd-mongrel dogs, randomly assigned to a metoprolol (M-) and placebo-group (P-group), occlusion of the left anterior descending coronary artery (LAD) followed by reperfusion with recombinant tissue plasminogen activator was performed. Regional myocardial blood flow (MBF) was measured by the radiolabelled microsphere technique. Blood samples from aorta and great cardiac vein were collected to evaluate the concentrations of MADP. The triphenyltetrazolium chloride perfusion and fixation technique was used for infarct size measurement. MBF in the area at risk decreased in both groups during ischemia, but it was significantly higher (p = 0.013) in M-group. Recanalization of LAD was associated with an increase in flow in postischemic vascular bed. MBF was significantly higher (p = 0.024) in P-group during late reperfusion. In M-group IS was smaller (p = 0.007) and VM was bigger (p = 0.007). The correlation between arterial adenosine concentration during early reperfusion and IS (p = 0.044, r = -0.588) or VM (p = 0.036, r = 0.607) in M-group was noted. Values of net MADP balances significantly increased during early reperfusion. The correlation between reperfusive net MADP balance and IS (p = 0.00005, r = 0.906) or VM (p = 0.016, r = -0.675) in M-group was observed. The amount of MADP released during reperfusion correlates with the IS and is inversely proportional to the area of VM. The endogenously released adenosine may have additional cardioprotective effect during beta-adrenergic blockade.

Influence of an early adrenergic blockade on thrombotic infarct size and myocardial metabolism

To evaluate the extent to which the protective effect of metoprolol was accompanied by changes in myocardial oxygen consumption and metabolism, thrombotic occlusion of coronary artery followed by infusion of metoprolol or placebo was performed in twenty four German Shepherds. To restore a coronary blood flow rt-PA was administered. Plasma levels of oxygen, glucose, lactic acid, non esterified fatty acids, triacylglyceride and adenosine breakdown products were measured before and at the end of the occlusion and in the early and late reperfusion periods. Regional myocardial blood flow was measured by means of radioactive tracer microspheres. Infarct size was estimated after perfusion and staining of excised hearts with Evans blue. Plasma levels of metoprolol were determinated before the end of occlusion and during reperfusion and therapeutic concentrations were confirmed. The infarct size was smaller in dogs receiving metoprolol (21.6 +/- 20.7 vs 43.0 +/- 17.3% p. < 0.02). Coronary collateral blood flow was greater in metoprolol than in placebo dogs (18.68 +/- 7.58 vs 11.05 +/- 6.10 ml/min/100g, p. < 0.01). As a consequence of myocardial ischemia a shift toward carbohydrate utilization, the myocardial lactate release and the accompanying symptoms of diminished myocardial lipid uptake were observed. A washout of adenosine degradation products during early reperfusion was also noticed. In beta 1 blocked animals the reduction of myocardial oxygen consumption and preserved myocardial uptake of lactate and non esterified fatty acids were documented.

[The role of calcium antagonists on coronary artery spasm and prevention of restenosis after angioplasty]

Classification, mechanism of action, hemodynamic and electrophysiological effects of calcium antagonists also structure of L-type calcium channel (cell receptor for this group of drugs) have been presented. Current views about the role of calcium channel antagonists in treatment of vasospastic angina pectoris, in particular Prinzmetal's angina, have been discussed. The use of calcium antagonists for the prevention of coronary restenosis after successful percutaneous transluminal coronary angioplasty have been analysed. Beneficial effects of calcium channel blockers (diltiazem 180 mg per day and verapamil 480 mg per day) for the prevention of restenosis after coronary angioplasty in a group of patients with stable angina pectoris have been demonstrated. Future directions in the trials on the calcium antagonists were been also presented.