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Biomedical subjects

G Gonzi

Publications and source records attributed to G Gonzi.

7 recordsLinked to original sources

[New strategies in the treatment of acute myocardial infarction].

A number of experimental and clinical studies have recently underlined the importance, in acute myocardial infarction, of platelet adhesion and aggregation after plaque rupture. During clot resolution, platelet-rich thrombi are relatively resistant to fibrinolytic agents, mainly due to the release of plasminogen inhibitor-1 by platelets which are activated as a result of the increase in thrombin generation induced by plasminogen activator therapy despite heparin administration. Platelet glycoprotein (GP) IIb/IIIa integrin receptor blockers prevent platelet aggregation by blocking the final pathway of platelet activation. Thus, they also prevent the formation of an intraluminal white thrombus without affecting adhesion. Animal and human studies have shown that the potent inhibition of platelet GP IIb/IIIa receptors can lead to modest reperfusion rates even without exogenous fibrinolytic therapy. This suggests that combining the "dethrombotic" effects of a GP IIb/IIIa antagonist with lower fibrynolytic doses may result in a synergistic effect. Preclinical studies including patients with myocardial infarction have shown that such combined treatment increases the incidence, speed and durability of reperfusion. It has also been proved to be useful in improving the microcirculatory coronary flow and in facilitating subsequent percutaneous coronary interventions. In the phase III GUSTO V trial, abciximab combined with 5 + 5 U of reteplase and low-dose weight-adjusted heparin led to a 30-day mortality rate that was similar to that obtained with full-dose reteplase (10 + 10 U) and standard heparin therapy, without causing a significant increase in the incidence of intracranial hemorrhage. The results of this trial offer a rationale for alternative reperfusion therapy, although further analyses, including a 1-year follow-up, are needed to define the patient groups that are most likely to benefit from such a new regimen.

Angioplasty↗

[Continuous veno-venous hemofiltration in acute renal insufficiency and heart failure].

The application of intermittent renal replacement therapies in critically ill patients with both acute renal failure and heart failure is often associated with circulatory instability and refractory hypotension. We have evaluated the efficacy and safety of a continuous technique (continuous veno-venous hemofiltration-CVVH) in 7 patients (1 male, 6 females, mean age 77 +/- 4 years) referred to our intermediate care unit for oliguria, acute renal failure and NYHA functional class IV, CVVH was performed by a peristaltic pump with blood flow at 200 ml/min, controlled ultrafiltration production rate (25 ml/min), minute to minute microprocessor controlled fluid balance system, biocompatible filters, low-dose prostacyclin for the extracorporeal circuit maintenance. Non invasive evaluation of cardiac function was performed by Doppler echocardiography. A total of 673 hours of CVVH were performed, with a mean extracorporeal circuit duration of 96 +/- 26 hours/patient (range 15-134). Daily urea clearance was 32 +/- 21. A mean body weight decrease of 10% was obtained (body weight before-CVVH 64.5 +/- 6 kg vs end-CVVH 58.5 +/- 5 kg, p < 0.01, paired data Student's test) without any hemodynamic worsening; metabolic control was adequate (urea before-CVVH 251 +/- 73 mg% vs end-CVVH 117 +/- 18 mg%, p < 0.01). Hospital survival was 42% (3/7 patients). In patients with acute renal failure and severe heart failure, CVVH allows an easy control of both fluid balance and acid-base equilibrium, along with the maintenance of acceptable hemodynamic stability.

Acid-Base Equilibrium↗

Cardiac arrhythmias during central venous catheter procedures in acute renal failure: a prospective study.

To define the frequency and risk factors of cardiac arrhythmias during central venous catheter procedures in acute renal failure, continuous electrocardiographic monitoring with permanent recording was performed before and during 201 guidewire insertions in 171 patients requiring a central venous catheter for parenteral nutrition and/or dialysis access (121 procedures in 107 patients with acute renal failure; 39 procedures in 31 patients with normal renal function; 41 procedures in 33 patients with ESRD on chronic hemodialysis). No differences in cardiac arrhythmia frequencies were found during baseline recording. New arrhythmias were documented in 85 cases (85/201; 42%) during the catheter procedure. Ventricular arrhythmia frequencies increased significantly in all groups, as compared with baseline values (P < 0.05 for the control group, P < 0.01 for the chronic hemodialysis group, P < 0.001 for the acute renal failure group); the most noteworthy increase was observed in the acute renal failure group. Statistically significant differences among frequencies of total ventricular arrhythmias, advanced ventricular arrhythmias, and ventricular tachycardia during central venous catheter procedures were found between the acute renal failure group and both the normal renal function group (P < 0.05 to P < 0.001), and the chronic hemodialysis group (P < 0.05 to P < 0.01). All arrhythmias resolved spontaneously soon after partial guidewire withdrawal; nine episodes were symptomatic (in one case, ventricular tachycardia, followed by 10 s asystolia); no death directly related to the catheter procedure was observed. BUN and serum creatinine levels, as well as guidewire length remaining inside the patient, were significantly higher (P < 0.01) in patients with cardiac arrhythmias during central venous catheter procedures as compared with patients without arrhythmias; differences in other variables known as possible risk factors for arrhythmias (anatomical position, preexistent cardiac disease, utilization of proarrhythmogenic drugs, hypoxemia, acid-base status, and serum electrolytes, etc.) were not significant. Our study suggests that (1) patients with acute renal failure are at increased risk for cardiac arrhythmias during central venous catheter procedures; (2) an important risk factor is also represented by guidewire overinsertion, a technical error that should be avoided.

Acute Kidney Injury↗

Hemodynamic, respiratory, and metabolic effects of medium-chain triglyceride-enriched lipid emulsions following valvular heart surgery.

STUDY: A lipid emulsion containing 10 percent medium-chain triglycerides (MCT) and 10 percent long-chain triglycerides (LCT) was infused at a rate of 1 ml/kg/h (3.3 mg/kg/min) for 2 h, in 12 patients (2 males, 10 females; mean age, 54 +/- 3 (SEM) years; range, 34 to 67 years) 24 h after open-heart surgery (mitral valve replacement). METHODS: Hemodynamic factors (pulmonary and radial artery indwelling catheters), oxygen and carbon dioxide partial pressures, oxygen saturation, oxygen delivery and consumption, and intrapulmonary shunt fraction were obtained before, during, and after lipid infusion (for 2 h), at 30-s intervals, along with some metabolic indexes (triglycerides, free fatty acids, glucose, insulin, lactate, acetoacetate). RESULTS: No statistically significant changes in heart rate, cardiac index, systemic and pulmonary pressures and resistances, central venous and pulmonary capillary pressures, or arterial oxygen partial pressure were observed during infusion. Arterial carbon dioxide partial pressure values were constantly reduced throughout and after the end of lipid infusion, as compared with baseline values, while oxygen consumption was increased significantly without any change in oxygen delivery. No adverse effects on intrapulmonary shunt fraction were observed. Statistically significant increases of triglycerides, free fatty acids, acetoacetate and insulin (peak values at end of the lipid infusion) were found in comparison with baseline values. Plasma glucose increased significantly during lipid infusion and remained higher than baseline values until the end of the study. Lactate levels were unchanged except for a slight decrease at the end of the study, without any derangement of acid-base equilibrium. Neither arrhythmias nor adverse clinical reactions were observed as a consequence of lipid infusion. CONCLUSIONS: Fat emulsions containing both MCT and LCT, when given at 3.3 mg/kg/min for 120 min following valvular heart surgery, do not exert negative cardiopulmonary effects, and could represent a source of rapidly metabolized substrates.

Acetoacetates↗