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Biomedical subjects

Giuseppe Fiore

Publications and source records attributed to Giuseppe Fiore.

10 recordsLinked to original sources

Superior mesenteric artery blood flow modifications during off-pump coronary surgery.

BACKGROUND: Patients undergoing cardiac surgery are at increased risk of gut hypoperfusion. During off-pump surgery, hemodynamic derangements at the time of heart displacement could reduce splanchnic perfusion, outweighing the beneficial effects of avoiding cardiopulmonary bypass. The purpose of this study is to assess, prospectively, blood flow modifications in the superior mesenteric artery during off-pump surgery using transesophageal echocardiography. METHODS: In 19 patients undergoing multivessel elective off-pump coronary revascularization, systemic hemodynamics and superior mesenteric flow were assessed. Blood flow in the superior mesenteric artery was evaluated with duplex ultrasound using a transesophageal echo probe. Measurements were made four times: T0 (baseline), T1 (left anterior descendent anastomosis), T2 (heart displacement to expose the inferolateral and inferior walls), and T3 (closed chest, at the end of surgery). RESULTS: Superior mesenteric blood flow significantly decreased at T2 (from 426.4 +/- 83.1 mL to 212.9 +/- 48.6 mL, p < 0.001), when also cardiac output was reduced. The percentage of the cardiac output directed toward the mesenteric arterial bed was also decreased at this time. At the end of surgery (T3), whereas cardiac output returned to the initial values, mesenteric flow was significantly increased compared with baseline, with a higher percentage of the systemic output flowing through the superior mesenteric artery. CONCLUSIONS: Hemodynamic changes during off-pump coronary surgery induce a significant mesenteric hypoperfusion followed by a hyperemic response at the end of surgery. Transesophageal echo-Doppler allows the intraoperative measurement of blood flow distribution to splanchnic viscera.

Aged↗

Ischemic mitral regurgitation: pathophysiology, diagnosis and surgical treatment.

Ischemic mitral valve regurgitation often complicates acute myocardial infarction and also represents a negative prognostic factor for long-term survival in patients undergoing surgical myocardial revascularization. While severe mitral regurgitation should always be corrected during a coronary artery bypass operation, the decision making is more difficult in patients with a mild-to-moderate degree of regurgitation. Recent studies and experimental protocols have elucidated the pathophysiological mechanisms leading to mitral regurgitation with great interest in annular modifications and subvalvular alterations. These data suggest that new and integrated surgical approaches that address annuloplasty ring sizing, ring type selection and tethering phenomenon (i.e., chordal cutting, 'edge-to-edge' technique and left-ventricular plasty techniques) are required for a safer and durable valve repair. Transthoracic and transesophageal echocardiography are useful in determining the etiology and the degree of mitral regurgitation, to assess mitral deformation and to measure indexes of global and regional left-ventricular remodeling. Stress echocardiography may unmask higher degrees of mitral regurgitation. More data are needed in order to confirm the promising and interesting preliminary experimental findings of magnetic resonance imaging in diagnosis and clinical evaluation of ischemic mitral regurgitation.

Coronary Artery Bypass↗

Nuclear targeting of Akt enhances ventricular function and myocyte contractility.

Cytoplasmic overexpression of Akt in the heart results in a myopathy characterized by organ and myocyte hypertrophy. Conversely, nuclear-targeted Akt does not lead to cardiac hypertrophy, but the cellular basis of this distinct heart phenotype remains to be determined. Similarly, whether nuclear-targeted Akt affects ventricular performance and mechanics, calcium metabolism, and electrical properties of myocytes is unknown. Moreover, whether the expression and state of phosphorylation of regulatory proteins implicated in calcium cycling and myocyte contractility are altered in nuclear-targeted Akt has not been established. We report that nuclear overexpression of Akt does not modify cardiac size and shape but results in an increased number of cardiomyocytes, which are smaller in volume. Additionally, the heart possesses enhanced systolic and diastolic function, which is paralleled by increased myocyte performance. Myocyte shortening and velocity of shortening and relengthening are increased in transgenic mice and are coupled with a more efficient reuptake of calcium by the sarcoplasmic reticulum (SR). This process increases calcium loading of the SR during relengthening. The enhanced SR function appears to be mediated by an increase in SR Ca2+-ATPase2a activity sustained by a higher degree of phosphorylation of phospholamban. This posttranslational modification was associated with an increase in phospho-protein kinase A and a decrease in protein phosphatase-1. Together, these observations provide a plausible biochemical mechanism for the potentiation of myocyte and ventricular function in Akt transgenic mice. Therefore, nuclear-targeted Akt in myocytes may have important implications for the diseased heart.

Actin Cytoskeleton↗

Hemodynamics in off-pump surgery: normal versus compromised preoperative left ventricular function.

OBJECTIVE: Off-pump coronary surgery (OPCABG), avoiding cardiopulmonary bypass and cardioplegic arrest, seems to be a better choice in patients with poor baseline cardiac function. Since cardiocirculatory collapse could be induced by heart displacement in this group of patients at high risk, a greater pathophysiologic understanding of the hemodynamic derangements occurring in such patients is needed. METHODS: Twenty-eight elective OPCABG patients were evaluated for hemodynamic changes induced by heart displacement, using arterial thermodilution to measure cardiac output and global end-diastolic volume. Hemodynamic parameters were recorded: at baseline; during proper exposure and stabilization of each vessel; and at the end of surgery. Patients were divided into two groups, according to baseline ejection fraction (EF): group A (EF>30%; N=16), group B (EF< or =30%; N=12). RESULTS: Heart displacement induced a significant drop in the cardiac and stroke index, with a lesser decrease of mean arterial pressure because of raised systemic vascular resistance. Preload, measured as global end diastolic volume, significantly decreased in group A, while it remained unchanged or increased in group B. Linear regression between the preload index and left ventricular stroke work was significant only in group A. CONCLUSIONS: Patients with poor baseline cardiac function can well tolerate OPCABG. However, the pathophysiologic modifications underlying the hemodynamic changes are different compared to those in patients with good preoperative cardiac performance.

Aged↗

Increased prothrombotic state lasting as long as one month after on-pump and off-pump coronary surgery.

OBJECTIVE: This study investigated whether the activation of coagulation, fibrinolysis, and endothelium occurring during the first postoperative month after on-pump coronary artery bypass surgery differs from that after off-pump coronary artery bypass grafting. METHODS: Thirty-five patients candidates to coronary surgery were randomized to undergo on-pump (n = 18) or off-pump (n = 17) coronary artery bypass grafting. Blood samples were collected before the intervention and to 1 month after surgery. RESULTS: Prothrombin fragment F1.2, thrombin-antithrombin complex, and D-dimer increased after surgery and were persistently higher than preoperative values as late as 30 postoperative days in both on- and off-pump groups; higher levels of these variables were detected after on-pump surgery relative to off-pump surgery only at the time point after termination of cardiopulmonary bypass (fragment F1.2 and thrombin-antithrombin complex) or from bypass end to 8 postoperative days (D-dimer). Fibrinogen levels decreased after surgery and then increased in parallel in both groups to 8 days after surgery. The von Willebrand factor level increased postoperatively in both groups and returned to baseline 30 days after surgery; it was higher after on-pump surgery from bypass end to 8 postoperative days. Soluble vascular cell adhesion molecule 1 was increased significantly from baseline in both groups 30 days after surgery, with no difference between groups. CONCLUSION: Patients undergoing off-pump surgery showed protection against activation of coagulation and fibrinolysis and against endothelial injury only during the intraoperative period; this was followed by the development of a prothrombotic pattern comparable to that of patients undergoing on-pump surgery lasting at least as late as 30 days after surgery.

Blood Coagulation↗

Association between migraine and Celiac disease: results from a preliminary case-control and therapeutic study.

OBJECTIVES: Subclinical celiac disease (CD) has been associated with various neurological disorders, the most common being neuropathy and cerebellar ataxia. The aims of the present study were to assess the following: 1) the prevalence of CD in patients affected by migraine; 2) whether there are regional cerebral blood flow abnormalities in migraine patients with CD compared to migraine patients without CD; and 3) the effects of a gluten free diet in migraine patients with CD. METHODS: A total of 90 patients affected by idiopathic migraine were enrolled, and 236 blood donors were used as controls. Serum IgG antitransglutaminase (TgA) and IgA antiendomysial (EmA) were measured. In positive cases, diagnosis was confirmed endoscopically. A gluten free diet was started in the patients diagnosed with CD, who were followed for 6 months. A single photon emission CT brain study was performed before and after a gluten free diet. RESULTS: Four of 90 (4.4%; 95% CI = 1.2-11.0) migraine patients were found to have CD compared with 0.4% (95% CI = 0.01-2.3) blood donor controls (p < 0.05). During the 6 months of gluten free diet, one of the four patients had no migraine attacks, and the remaining three patients experienced an improvement in frequency, duration, and intensity of migraine. Single photon emission CT studies showed a regional baseline reduction in brain tracer uptake in all four patients. Such reduction in uptake completely resolved at follow-up. CONCLUSIONS: Our results suggest that a significant proportion of patients with migraine may have CD, and that a gluten free diet may lead to a improvement in the migraine in these patients.

Adult↗

Preventative effect of repeated nasal applications of capsaicin in cluster headache.

Preliminary studies have shown that repeated nasal applications of capsaicin prevented the occurrence of cluster headache attacks. The present study was designed to verify the difference in efficacy of treatment with nasal capsaicin, depending on the side of application. Fifty-two patients affected by episodic form were divided into 2 groups, one receiving the treatment on the same side where the attacks occurred (ipsilateral side), the other on the controlateral side. Eighteen patients with a chronic form alternately received both ipsilateral and controlateral treatments. Seventy percent of the episodic patients, treated on the ipsilateral side, showed a marked amelioration whereas no improvement was noted in the patients treated on the contralateral side. The efficacy of ipsilateral treatment was emphasized by the results obtained in chronic patients. However, in these patients, the maximum period of amelioration lasted no more than 40 days. The difference between the effects of the 2 treatments (contralateral and ipsilateral) was statistically significant in both episodic and chronic sufferers. The efficacy of repeated nasal applications of capsaicin in cluster headache is congruent with previous reports on the therapeutic effect of capsaicin in other pain syndromes (post-herpetic neuralgia, diabetic neuropathy, trigeminal neuralgia) and supports the use of the drug to produce a selective analgesia.

Administration, Intranasal↗

Heart rate variability in cluster headache.

Eight patients with cluster headache were studied by evaluating the heart rate variability on the basis of 24-hour ECG monitoring performed during attacks (critic periods) to demonstrate if any imbalance of the autonomic nervous system was present and to determine its temporal correlation, if any, with the attack. The same monitoring allowed us to compare the patients' data during headache-free periods (intercritic periods) with those of normal controls. Our investigation demonstrated a severe sympathovagal imbalance during spontaneous attacks: the parasympathetic drive is at once increased at the onset with a mild reduction of the sympathetic drive, and all these modifications slowly disappear at the end of each attack. Comparison of the average low-frequency and high-frequency values during intercritic periods showed a significant reduction in the low-frequency values in patients, even when the low-frequency/high-frequency ratio was normal. This is highly suggestive of the presence of an autonomic nervous system dysfunction.

Adult↗