Percutaneous treatment of non-functioning arteriovenous fistulas.

AIM: To show our results in the percutaneous treatment of non-functioning arteriovenous fistulas of patients undergoing haemodialysis and to discuss the results of the literature. METHODS: Thirty-four patients with 37 non-functioning arteriovenous fistulas (29 native, 8 grafts) underwent percutaneous angioplasty. Restoration of vessel lumen and function at the following dialysis were considered as successful outcome. Primary and secondary patency rates at 12 months were calculated by means of Kaplan-Meier analysis. RESULTS: Fifty-six interventions were performed, 42 on native fistulas and 14 on grafts. Immediate technical and clinical success were obtained in 98% of procedures. For native fistulas, primary and secondary patency rates at 12 months were 41% and 62%, respectively. For grafts, 14% and 34%, respectively. Only one complication was observed. CONCLUSION: Minimally invasive percutaneous treatment allows to restore function of most arterio-venous fistulas with good long term patency.

Effect of transdermal nitroglycerin or N-acetylcysteine, or both, in the long-term treatment of unstable angina pectoris.

OBJECTIVES: This study was designed to evaluate whether the addition of transdermal nitroglycerin or oral N-acetylcysteine, or both, to conventional medical therapy improves the natural history of unstable angina pectoris. BACKGROUND: Transdermal nitroglycerin is widely used to treat angina pectoris, but the development of tolerance is a major problem that may reduce its clinical efficacy. It has been suggested that the addition of N-acetylcysteine to nitroglycerin reverses the development of tolerance, potentiates the hemodynamic response to nitroglycerin and may improve in-hospital prognosis in unstable angina. METHODS: We assessed the efficacy of adding transdermal nitroglycerin or oral N-acetylcysteine, or both, to conventional medical therapy in a randomized, double-blind, placebo-controlled trial involving 200 patients with unstable angina who were followed up for 4 months. RESULTS: Outcome events--death, myocardial infarction or refractory angina requiring revascularization--occurred in 31% of patients receiving nitroglycerin, 42% of those receiving N-acetylcysteine, 13% of those receiving nitroglycerin plus N-acetylcysteine and 39% of those receiving placebo (p = 0.0052). Kaplan-Meier curves showed a higher probability (p < 0.01) of no failure of medical treatment in the group receiving both nitroglycerin and N-acetylcysteine than in those receiving placebo, N-acetylcysteine or nitroglycerin alone. The combination of nitroglycerin and N-acetylcysteine was associated with a high incidence of side effects (35%), mainly intolerable headache, which was almost twice as frequent as in patients receiving nitroglycerin alone. CONCLUSIONS: The combination of nitroglycerin and N-acetylcysteine, associated with conventional medical therapy in the long-term treatment of patients with unstable angina, reduces the occurrence of outcome events. However, the high incidence of side effects limits the clinical applicability of this therapeutic strategy at least at the dosage used in the present study.

Thrombin activity and early outcome in unstable angina pectoris.

BACKGROUND: The blood coagulation system is frequently activated in the acute phase of unstable angina, but it is unknown whether the augmented function of the hemostatic mechanism may serve as a marker of increased risk for an early unfavorable outcome. METHODS AND RESULTS: Plasma concentrations and 24-hour urinary excretion of fibrinopeptide A were prospectively determined in 150 patients with unstable angina. All patients underwent 24-hour Holter monitoring, during which time urine was collected; at the end of this period, a blood sample was taken and coronary arteriography was performed. The patients were followed up for the occurrence of cardiac events (death and myocardial infarction) until they underwent coronary revascularization or until they were discharged from the hospital. Fibrinopeptide A plasma levels and 24-hour urinary excretion were found to be abnormally elevated in 50% and 45% of the study population, respectively. During hospitalization, 11 patients developed myocardial infarction and 2 patients died. Kaplan-Meier analysis demonstrated a significantly higher probability of developing cardiac events in patients with abnormal rather than normal plasma levels of fibrinopeptide A (P<.01), whereas no difference in outcome was observed between patients with normal and those with abnormal 24-hour urinary excretion. Cox regression analysis showed that the only variables independently related to an early unfavorable outcome were the presence of persistent ischemia during 24-hour Holter monitoring (P<.0001), the presence of intracoronary thrombosis at angiography (P=.016), and abnormal fibrinopeptide A plasma levels (P=.038). CONCLUSIONS: Patients with unstable angina pectoris and abnormal fibrinopeptide A plasma levels are at increased risk for an early unfavorable outcome.

[Treatment with erythropoietin and iron requirements in dialyzed patients]. / Trattamento con eritropoietina (Epo) e fabbisogno di ferro nel paziente dializzato.

The use of erythropoietin in dialysed patients leads to the gradual depletion of the body's iron reserves. It is important to assay iron blood levels in both patients receiving Epo therapy and those undergoing dialysis without this treatment. The most common method used is to assay ferritinemia, transferrinemia and the transferrin saturation levels. Using a retrospective study it was found that there is no significant difference in the request for iron supplementation in patients receiving Epo treatment compared to a control group not treated with Epo.

[Vascular access for hemodialysis. Our experience in 20 years]. / Accessi vascolari per emodialisi. Nostra esperienza in 20 anni.

A personal series arterio-venous fistulas from the last 20 years is examined. The authors have tried to verify the correctness of their present proctocol which is based on the abolition of those fistulas applied to the anatomic tabac. In fact in some cases they have caused problems of flow, but in other cases they have lasted much longer than any other kind of fistulas.

Fibrinopeptide A excretion in urine: a marker of the cumulative thrombin activity in stable versus unstable angina patients.

Plasma levels and 24-hour urine excretion of fibrinopeptide A were measured in a consecutive series of 179 patients with angina pectoris. Sixty-four patients had stable angina and 115 patients had unstable angina. Urine was collected over 24 hours the day before coronary arteriography, and blood samples were taken at the end of urine collection. When the values of fibrinopeptide A in plasma and in the 24-hour urine specimens were compared, no significant correlation was found in patients with either stable (rs = 0.16, difference not significant) and unstable (rs = 0.07, difference not significant) angina. The concentrations of fibrinopeptide A in the plasma did not differ significantly when patients with stable angina (range 0.1 to 82.6, median 7.4 ng/mL) were compared with patients with unstable angina (range 0.2 to 61.7, median 14 ng/mL, p = 0.055), whereas fibrinopeptide A 24-hour urinary excretion was significantly higher in patients with unstable angina (range 0.3 to 38.1, median 11.8 micrograms/24 hr) than in patients with stable angina (range 0.4 to 38.1, median 3.8 micrograms/24 hr, p less than 0.001). Twenty-four-hour urine excretion of fibrinopeptide A in patients with unstable angina and angiographically documented intracoronary thrombi were higher than the corresponding values in patients with unstable angina without such angiographic characteristic (p less than 0.001). The largest increase in plasma and urine concentration of fibrinopeptide A was observed in patients whose first episode of angina at rest occurred within the previous 48 hours. We conclude that the cumulative thrombin activity, assessed by 24-hour urinary excretion of fibrinopeptide A, is a more useful index, compared with single fibrinopeptide A measurement in plasma, for discriminating between patients with stable and with unstable angina pectoris.

[Erythropoietin treatment in Piedmont and Valle d'Aosta]. / Il trattamento con eritropoietina in Piemonte e Valle d'Aosta.

The paper reports a study carried out in the Dialysis Centres of Piedmont and the Aosta Valley on the use of erythropoietin in the treatment of anemia in patients undergoing regular dialysis. The efficacy of the drug and collateral and/or undesirable effects were evaluated. It was found that the drug was efficacious in 99.2% of the 342 patients receiving treatment on 30-6-1990, whereas undesirable effects were observed in 14.6% of cases. Data from the Nephrology and Dialysis Service in Asti are also reported.

Usefulness of the hyperventilation test in stable exertional angina pectoris in selecting medical therapy.

To assess the prevalence of abnormal coronary vasoconstriction in stable exertional angina and to evaluate whether the presence of increased coronary tone may have therapeutic implications, we studied 83 consecutive patients with typical exertional angina, positive response to exercise stress testing and documented coronary artery disease. Abnormal coronary vasoconstriction was induced by a hyperventilation test in 16 patients (group I) while the remaining 67 had a negative response (group II). No differences were observed between the 2 groups with regard to clinical, exercise and angiographic data. All group I patients and 16 patients in group II repeated hyperventilation and exercise tests after the administration of dihydropyridine-type calcium antagonists (7 patients nifedipine, 9 patients felodipine). After treatment 15 of 16 group I patients had a negative response to the hyperventilation test. The total exercise duration was significantly increased (278 +/- 183 vs 554 +/- 248 seconds; p less than 0.001) with higher values of rate pressure product at peak exercise (168 +/- 47 vs 235 +/- 67 mm Hg x beats/min/100; p less than 0.0025). In group II no significant differences were observed between pre- and posttreatment values for total exercise duration (244 +/- 210 vs 308 +/- 243 seconds) and rate pressure product at peak exercise (170 +/- 46 vs 188 +/- 56 mm Hg x beats/min/100). These data show that the hyperventilation test can be used to select a subset of patients with stable exertional angina and detectable abnormal coronary vasoconstriction who will improve their exercise tolerance with coronary vasodilator treatment.

Significance of hyperventilation-induced ST segment depression in patients with coronary artery disease.

To investigate the significance of hyperventilation-induced ST segment depression, 329 consecutive patients with angina and documented coronary artery disease who underwent hyperventilation and exercise tests during pharmacologic washout were studied. The hyperventilation test induced ST segment depression in 79 patients. In 36 of these 79 patients, the electrocardiographic changes occurred early during overbreathing (Group I), whereas in 26 they occurred late during recovery (Group II). Seventeen patients developed ST segment depression both during over-breathing and during recovery (Group III). Group I patients had a higher frequency of history of angina during exercise, multivessel disease and lower tolerance to exercise as compared with patients in Group II. In Group I, the rate-pressure product at the time to onset of ST depression during overbreathing was similar to that during exercise (152 +/- 24 versus 148 +/- 42; p = NS), whereas in Group II the rate-pressure product at the time to onset of ST depression during recovery was comparable with that under control conditions (104 +/- 30 versus 98 +/- 27; p = NS) and far less than that required to produce ischemia during exercise (104 +/- 30 versus 201 +/- 56; p less than 0.0011). In nine Group III patients, the acute administration of propranolol prevented the early hyperventilation-induced ST segment depression, whereas nifedipine abolished the delayed hyperventilation-induced ST segment depression. These findings suggest that early hyperventilation-induced ST segment depression is due to increased oxygen demand in patients with poor coronary reserve and may be prevented by beta-adrenergic blockers, which are useful for lowering oxygen consumption.(ABSTRACT TRUNCATED AT 250 WORDS)