MicroRNAs in myocardial ischemia: identifying new targets and tools for treating heart disease. New frontiers for miR-medicine

MicroRNAs (miRNAs) are natural, single-stranded, small RNA molecules which subtly control gene expression. Several studies indicate that specific miRNAs can regulate heart function both in development and disease. Despite prevention programs and new therapeutic agents, cardiovascular disease remains the main cause of death in developed countries. The elevated number of heart failure episodes is mostly due to myocardial infarction (MI). An increasing number of studies have been carried out reporting changes in miRNAs gene expression and exploring their role in MI and heart failure. In this review, we furnish a critical analysis of where the frontier of knowledge has arrived in the fields of basic and translational research on miRNAs in cardiac ischemia. We first summarize the basal information on miRNA biology and regulation, especially concentrating on the feedback loops which control cardiac-enriched miRNAs. A focus on the role of miRNAs in the pathogenesis of myocardial ischemia and in the attenuation of injury is presented. Particular attention is given to cardiomyocyte death (apoptosis and necrosis), fibrosis, neovascularization, and heart failure. Then, we address the potential of miR-diagnosis (miRNAs as disease biomarkers) and miR-drugs (miRNAs as therapeutic targets) for cardiac ischemia and heart failure. Finally, we evaluate the use of miRNAs in the emerging field of regenerative medicine.

Five year prognosis of an Italian cohort of juvenile acute myocardial infarction patients

AIM

The aim of this study was to describe the five-year prognosis of an Italian cohort of patients following acute myocardial infarction (AMI) occurred at age ≤ 45 years and to investigate the potential role of risk predictors for future cardiovascular events (CVE).

METHODS

The study enrolled 112 consecutive patients aged ≤ 45 years admitted to our Coronary Care Unit between March 1995 and January 2007 because of AMI. Clinical characteristics, extent of coronary vessel disease by angiogram and cardiovascular risk factors (including diet, physical activity, alcohol and coffee consumption) were registered.

RESULTS

Complete follow-up data was available for 104 (93%) patients with a duration of follow-up of 5.3 (2.9-7.6) years. Twenty-four (23%) patients presented with a new CVE: 16 (15%) angina pectoris, 6 (6%) recurrent AMI, one heart failure and one cardiac death. One in every five patients presented left ventricle systolic function below 50%. Multivariate analysis (Cox proportional regression model) proved physical activity as an independent predictor of new CVE occurrence (P=0.014). Patients who practised moderate aerobic physical activity for at least two hours per week following AMI had significantly higher event-free survival compared with inactive controls (P=0.029).

CONCLUSION

Five-year prognosis of juvenile AMI is poor, with one in every five patients presenting a new CVE. Based on the present cohort of patients physical activity following first event plays a relevant prognostic role, supporting the need of careful lifestyle counselling.

[A case of pulmonary thromboembolism after interruption of treatment with unfractionated heparin]

Pulmonary embolism is a quite frequent event (incidence 1/10000/year), and blood stasis, endothelial lesions and coagulation disorders are predisposable factors. Elective treatment is heparin, but the use of this medication is associated with a possible ipercoagulative rebound effect. The case presented is a patient with unstable angina treated with heparin infusion, who developed pulmonary embolism after discontinuation of heparin treatment; the patient didn't present a genetic coagulopathy. Others risk factors have been analyzed and it was observed that discontinuation of heparin infusion could have a predominant role in the development of thrombosis. A MedLine research on the rebound effect of heparin and how to reduce it has been carried out.

Mortality and morbidity in reoperation comparing to first intervention in coronary revascularization

BACKGROUND

Coronary artery reoperation represents about 20% of coronary artery operations. In this study we compared mortality and morbidity of first intervention and redo operation.

METHODS

EXPERIMENTAL DESIGN

a retrospective study.

SETTINGS

patients who underwent coronary artery reoperations in a University Cardiac Surgery Division in 1991-1994.

PATIENTS

our clinical survey was composed of two groups: group A included 44 consecutive patients (mean age 60+/-7 years, males/females=41/3) who underwent a coronary artery reoperation in the years 1991-1994 at the University Cardiac Surgery Division of Turin; group B included 344 patients (mean age 58+/-8 years, males/females=289/55) randomly selected among those who underwent a first coronary operation in the above indicated period of time and centre. All patients had angina pectoris refractory to maximal medical therapy.

INTERVENTIONS

all patients underwent a coronary artery operation in extracorporeal circulation (ECC), under mild hypothermia (30-32 degrees C), during a single aortic clamp period, with antegrade cold crystalloid cardioplegia (St. Thomas).

MEASURES

comparison of clinical preoperative features, risk factors and postoperative mortality and morbidity between the two groups.

RESULTS

In reoperated patients we observed a greater mean akinesis score (p<0.001) and severe left ventricular dysfunction presence (p=0.014). Reoperation mortality was 11.4% against first operation mortality of 3.2% (p=0.03). Female gender (p=0.03), intra-aortic balloon counterpulsation need (p=0.002), adrenaline use (p=0.004) and low cardiac output syndrome (p=0.007) were all perioperative risk factors in group A.

CONCLUSIONS

Coronary artery reoperation involves a higher mortality and morbidity compared to the first operation, especially related to the reduced left ventricular function which characterises the population that undergoes reoperation.

Myocardial infarction before the age of 40 years is associated with insulin resistance

Insulin resistance is associated with atherosclerosis, and hyperinsulinemia is predictive of coronary heart disease. However, a quantitative estimation of in vivo insulin sensitivity in juvenile myocardial infarction is still lacking and the mechanism of hyperinsulinemia is unknown. We estimated insulin sensitivity, beta-cell secretion, and hepatic insulin extraction using the minimal model analysis of a frequently sampled intravenous glucose tolerance test (FSIGT) in 25 normal-weight subjects without glucose intolerance and hypertension who had an acute myocardial infarction before the age of 40 years, and 10 control subjects comparable for age, sex, body mass index, and blood pressure. All patients underwent a coronary angiography. Insulin sensitivity was significantly lower in patients than in control subjects (mean +/- SEM, 4.6 +/- 0.6 v8.5 +/- 1.2 10(-4). min(-1)(microU/mL), P = .002). The basal C-peptide secretion rate (P = .02), total C-peptide secretion (P = .005), area under the curve (AUC) of insulin (P = .04) and C-peptide (P = .01), and hepatic insulin extraction (P = .04) were higher in patients versus control subjects. In conclusion, insulin resistance is evident in subjects with early myocardial infarction accurately selected to avoid the influence of other factors known to reduce insulin sensitivity, and hyperinsulinemia is due to an increase in beta-cell secretion rather than a decrease in hepatic insulin extraction.

[Ischemic cardiovascular diseases. Correlation with Helicobacter pylori infection]

Coronary heart disease is the primary cause of mortality in western countries. The well-established ("classical") risk factors cannot fully explain epidemiological variations of this disease. From several years infections have been linked to ischemic vascular events and recent studies pointed to the role of Helicobacter pylori (H. pylori), a spiral Gram negative bacterium, that chronically infects human stomach and is involved in the pathogenesis of gastritis and peptic ulceration. Systematic reviews of studies have suggested the existence of a possible weakly positive association between this bacterium and coronary heart disease, but this could be due to confounding bias and influenced by the degree of investigations heterogeneity. Experiments from animal studies demonstrated that H. pylori infection in mice induces the formation of platelet aggregates and in contrast to Chlamydia pneumoniae it has not been found in the plaque: therefore, the role of H. pylori, could be even more important in the acute phase of myocardial infarction. There is the need for extensive prospective studies to evaluate the incidence of these diseases in relation to the presence of H. pylori infection. Appropriately randomized studies employing an antibiotic treatment for patients affected by ischemic vascular disease will answer the question of whether H. pylori has a causal role in the pathogenesis of acute myocardial infarction and ischemic stroke.

Ischemic cardiovascular disease and Helicobacter pylori. Where is the link?

Coronary heart disease (CHD) is the leading cause of death in western countries. Although several major risk factors have been identified, they fail to account for all the epidemiological variants of the disease, thus warranting research into novel causal agents. Cardiovascular diseases have long been associated with chronic infections acting through the activation of inflammatory pathways, and antibiotic therapy has been shown to produce a dramatic decrease in the rate of disease recurrence in patients with a history of myocardial infarction or unstable angina. The link between Helicobacter pylori (H. pylori) infection and CHD, first described by Mendall et al. in 1994, has been the subject of a multitude of epidemiological and clinical studies; however, these have been so heterogeneous that not two of them are based on a comparable selection of patients and focused on the same kind of disease, e.g. stable coronary heart disease or acute myocardial infarction. Evidence from animal studies supports the thesis that H. pylori plays an extremely important role in the acute phase of myocardial infarction: the bacterium causes platelet aggregation and induces pro-coagulant activity in experimentally infected mice. H. pylori may also contribute to atherosclerosis through an auto-immune process against endothelial cells or an increased concentration of homocysteine in the blood due to decreased levels of folic acid and cobalamin. The exact role of H. pylori cannot yet be fully assessed: there is a clear and present need for further studies with appropriate epidemiological and clinical approaches to investigate through prospective and interventional trial the possible causal relationship between H. pylori and CHD.

Exhaled nitric oxide in systemic sclerosis: relationships with lung involvement and pulmonary hypertension

OBJECTIVE

To measure nitric oxide (NO) concentration in exhaled air of patients with systemic sclerosis (SSc) and to investigate its relationships with lung involvement, complicated or not by pulmonary hypertension (PH).

METHODS

Exhaled NO was measured by chemiluminescence in 47 patients with SSc (16 with PH) and in 30 controls. All the patients underwent Doppler echocardiography to assess pulmonary artery pressure (PAP), lung function tests, and thin section computed tomographic scans of the lung to quantify the extent of fibrosing alveolitis.

RESULTS

Exhaled NO levels were higher in patients with SSc (16.6 +/- 9.1 ppb), particularly those with interstitial lung disease (ILD) (18.3 +/- 10.4 ppb), compared to controls (9.9 +/- 2.9 ppb; p < 0.0001). In patients with PH, exhaled NO was less than in patients without PH (10.7 +/- 5.9 vs 19.6 +/- 9 ppb, respectively; p < 0.001), and patients with PH without ILD had even lower exhaled NO than patients with PH and ILD (6.6 +/- 1.1 vs 12.6 +/- 6.3 ppb; p = 0.004). There was an inverse correlation between PAP and exhaled NO (r = 04).53, p = 0.004). Exhaled NO was not correlated to age, disease duration, current therapy, or form of disease (limited or diffuse).

CONCLUSION

The increased concentration of exhaled NO in patients with SSc may reflect respiratory tract inflammation. The relatively low value of exhaled NO in patients with PH and the negative correlation between PAP and exhaled NO suggest the important role of NO in regulating pulmonary vascular resistance in patients with SSc.

Acute myocardial infarction in young adults: prognostic role of angiotensin-converting enzyme, angiotensin II type I receptor, apolipoprotein E, endothelial constitutive nitric oxide synthase, and glycoprotein IIIa genetic polymorphisms at medium-term follow-up

BACKGROUND

A number of reports have investigated the association between various gene polymorphisms and the phenotypic expression of myocardial infarction. No investigations have evaluated the prognostic role of genetic factors in young people with premature coronary disease. The aim of this study was to investigate the influence of genetic factors compared with that of conventional risk factors on follow-up events in a population of Italian young adults with myocardial infarction.

METHODS AND RESULTS

The study population consisted of 106 young patients (mean age 40 +/- 4 years, range 23 to 45 years) with diagnosis of acute myocardial infarction. Clinical and genetic data from the group of patients with events during follow-up were compared with those from patients without events. The following genetic polymorphisms were tested: angiotensin I converting enzyme, angiotensin II type I receptor, apolipoprotein E (ApoE), endothelial constitutive nitric oxide synthase, and platelet glycoprotein IIIa. Coronary angiography was performed in 94 patients. Coronary angiography showed coronary artery disease in 93% of patients. During follow-up (46 +/- 12 months, range 25 to 72) the overall combined end points (cardiac death, myocardial infarction, and revascularization procedures) accounted for 21 events. Family history of coronary artery disease, smoking, stenosis of the left anterior descending artery at coronary angiography, and ApoE polymorphism (presence of epsilon4 allele) were significantly more prevalent (univariate analysis) in the group of patients with events. Logistic multivariate analysis showed that ApoE polymorphism (P =. 004, odds ratio [OR] 6.8, 95% confidence interval [CI] 2 to 22), family history (P =.005, OR 8.3, 95% CI 2 to 35), smoking after acute myocardial infarction (P =.008, OR 10.9, 95% CI 2 to 62), and left anterior descending coronary artery disease (P =.02. OR 6.6, 95% CI 1.3 to 33) were independent predictors of adverse events.

CONCLUSIONS

Myocardial infarction at a young age is commonly characterized by evidence of multiple cardiovascular risk factors and by a favorable prognosis in short- and medium-term follow-up. Evidence of significant disease at coronary angiography suggests the presence of a premature atherosclerotic process. ApoE polymorphism (presence of epsilon4 allele) appears to be a strong independent predictor of adverse events, suggesting a remarkable influence in the accelerated coronary disease.

Role of lipid, apolipoprotein levels and apolipoprotein E genotype in young Italian patients with myocardial infarction

BACKGROUND AND AIM

Studies of young patients with acute myocardial infarction (AMI) have demonstrated that conventional risk factors are usually responsible for their premature atherosclerosis. No account has yet been published of the risk profile of young Italians surviving an AMI. In this study, the conventional risk factors, lipids and apolipoproteins, and apolipoprotein E (APOE) allele distribution were evaluated in 98 consecutive AMI survivors (94 males, 4 females) aged 40.1 +/- 3.9 for at least three months after their acute event. These survivors were matched for age, sex, body mass index and presence of diabetes mellitus with 98 controls selected from subjects admitted to the same hospital for other reasons.

METHODS AND RESULTS

Lipid profiles and APOE polymorphism were determined in both groups. Coronary angiography during hospitalization showed the absence of critical stenosis in 6.6% of the survivors, mono-vessel disease in 57.7%, and multi-vessel disease in 35.5%. The survivors had a higher frequency of smoking, hypertension, family history for coronary artery disease (CAD) and dyslipidemia, and a much greater frequency of 3 or more risk factors than the controls: Odd ratios (OR) 7.4, 95% confidence interval (CI) 2.5-18.6, p = 0.0000. Significant differences were found between the groups for triglycerides (p = 0.000002), total cholesterol (p = 0.003), LDL-cholesterol (p = 0.012), HDL-cholesterol (p = 0.0002), apolipoprotein AI (p = 0.00001), and Apolipoprotein B (p = 0.000001). No differences were observed in APOE allele distribution (APOE*4 0.11 vs 0.08, APOE*3 0.86 vs 0.89, APOE*2 0.03 vs 0.03), nor in lipid profile when both higher risk genotype (E3/4, E4/4, E2/4) and lower risk genotype groups (E2/2, E2/3, E3/3) were analysed. OR were calculated as measures of the association of the E4-positive genotypes with AMI. They indicated a non-significant increase in risk of AMI when the survivors were compared with the controls (OR 1.78, 95% CI 0.84-3.70, p = 0.13).

CONCLUSIONS

This study provides further evidence that conventional coronary risk factors are usually present in young AMI patients. The APOE*4 allele was associated with a 1.8 non-significant increase in the risk of AMI in our group with premature CAD. Comparison with controls showed that the presence of three or more risk factors sharply increased the probability of premature CAD and that hyper-triglyceridemia is an independent risk factor. The data on APOE polymorphism are less certain and a larger study is needed.

Prognostic implications of detection of troponin I in patients with unstable angina pectoris

In our study, troponin I was not a predictor of cardiac events and a negative troponin I test did not exclude the presence of severe coronary artery disease. A positive troponin I test in patients with unstable angina identified a subgroup with probable, more active coronary disease (with higher levels of C-reactive protein).

Exhaled nitric oxide and impaired oxygenation in cirrhotic patients before and after liver transplantation

BACKGROUND

Nitric oxide may be involved in the impaired oxygenation of cirrhotic patients, a condition that improves in most patients after liver transplantation.

OBJECTIVE

To compare oxygenation and nitric oxide concentrations before and after liver transplantation.

DESIGN

Before-and-after observational study.

SETTING

Academic medical center.

PATIENTS

18 patients with cirrhosis and no obvious cardiopulmonary disease who underwent successful orthotopic liver transplantation.

INTERVENTION

Orthotopic liver transplantation.

MEASUREMENTS

Blood gas analysis, measurement of exhaled nitric oxide, contrast-enhanced echocardiography, and pulmonary function tests.

RESULTS

Before transplantation, the mean (+/- SD) exhaled nitric oxide concentration was higher in patients than in normal controls (13 +/- 4.9 parts per billion [ppb] compared with 5.75 +/- 1.9 ppb; P < 0.001). After transplantation, the alveolar-arterial oxygen gradient significantly decreased (from 17.3 +/- 7.1 mm Hg to 9 +/- 5.2 mm Hg; P < 0.001), as did the exhaled nitric oxide concentration (from 13 +/- 4.9 ppb to 6.2 +/- 2.8 ppb; P < 0.001). The decrease in the exhaled nitric oxide concentration was significantly correlated with the decrease in the alveolar-arterial oxygen gradient (r = 0.56; P = 0.014). Five patients met the criteria for the diagnosis of the hepatopulmonary syndrome before transplantation; the syndrome was cured by transplantation.

CONCLUSIONS

The correlation between the decrease in exhaled nitric oxide concentration after liver transplantation and the improvement in oxygenation reinforces the hypothesis that nitric oxide is an important mediator of impaired oxygenation in patients with cirrhosis.

Clinical and epidemiological characteristics of juvenile myocardial infarction in Italy: the GISSI experience

BACKGROUND

No clinical and epidemiological data are available about acute myocardial infarction (AMI) at a young age in large populations, due to the low prevalence of AMI in younger people. The aim of the present study is to analyze epidemiological and clinical characteristics of AMI among younger people in Italy, using the data bases of the three GISSI studies.

METHODS

Analysis of epidemiological and clinical characteristics of AMI according to different age groups in the three GISSI studies that collected data from 1985 to 1993.

RESULTS

In the GISSI-2 and GISSI-3 data bases, the prevalence of AMI at a young age (2 and 1.8% respectively; difference -0.2% with 95% CI from -0.4 to 0.3%), hospital mortality (2.3 and 1.9% respectively; difference -0.4% with 95% CI from -1.9 to 1.0%), and the rate of young female patients (8 and 7% respectively; difference -1% with 95% CI from -3.6 to 1.6%) are similar. In the GISSI-2 study, we observed that in comparison to elderly patients (> 70 years) young patients (< 40 years) are more frequently smokers (83.9 vs 21.0%; difference 62.9% with 95% CI from 58.5 to 67.3%) and have a higher rate of family history for CAD (42.1 vs 21.1%; difference 21.0% with 95% CI from 15.3 to 26.7%) and of hypercholesterolemia (28.3 vs 15.0%; difference 13.3% with 95% CI from 18.5 to 80.8%), but show a lower prevalence of hypertension (12.2 vs 44.3%; difference from -32.1% with 95% CI from -28.0 to -36.2%) and diabetes (2.9 vs 18.8%; difference -15.9% with 95% CI from -13.5 to -18.3%). AMI at a young age is generally the first event in ischemic heart disease; in comparison with older patients with previous AMI (6.4 vs 17.4%; difference -11.0% with 95% CI from -7.8 to -14.0%) and history of angina (23.2 vs 40.0%, difference -16.8% with 95% CI from -11.8 to -21.9%) this is less frequent. The rate of complications is lower in younger as opposed to older patients for both early (7.7 vs 31.2%; difference -23.5% with 95% CI from -20.0 to -26.9%) and late heart failure (2.9 vs 18.5%; difference -15.6% with 95% CI from -13.2 to -18.0%), as well as for angina (6.4 vs 10.5%; difference -4.1% with 95% CI from -1.1 to -7.1%), reinfarction (1.0 vs 3.3%; difference -2.3% with 95% Ci from -1.1 to -3.6%) and complete AV block (1.6 vs 6.6%; difference -5.0% with 95% CI from -3.3 to -6.7%). In young patients, we observed lower in-hospital (1.6 vs 21.1%; difference -19.5% with 95% CI to -21.6%) and six-month mortality (1.3 vs 8.1%; difference -6.8% with 95% CI from -5.0 to -8.5%).

CONCLUSIONS

The incidence and mortality of AMI at a young age was steady during the period between 1988 and 1993. AMI at a young age is a clinical entity with specific characteristics that differ from those found in old patients. In addition, it has peculiar risk profile with a better short- and medium-term outcome.

Lack of relationship between the P1A1/P1A2 polymorphism of platelet glycoprotein IIIa and premature myocardial infarction

BACKGROUND

The P1A1/P1A2 polymorphism of the platelet glycoprotein IIIa has been variably associated with an increased risk of coronary thrombosis.

MATERIALS

We investigated the linkage between the P1A1/P1A2 polymorphism and the risk of myocardial infarction in 98 patients who suffered their first myocardial infarction at the age of 45 years or less and 98 well-matched control subjects without coronary artery disease. Lipid parameters were measured using conventional methods of clinical chemistry; P1A genotypes were determined by polymerase chain reaction and restriction enzyme digestion.

RESULTS

There was no significant difference in the prevalence of P1A2-positive genotypes (either P1A1/P1A2 or P1A2/P1A2) between patients and control subjects (chi 2 = 0.66, d.f. = 1, P = 0.41).

CONCLUSIONS

These results suggest that the P1A2 polymorphism of the platelet glycoprotein IIIa does not contribute to the genetic susceptibility to premature myocardial infarction.

Administration of thrombolytic therapy to 17,944 patients with acute myocardial infarction: the GISSI-3 database

BACKGROUND

There is growing interest in assessing therapy for acute myocardial infarction. Because thrombolysis was not a study therapy in the GISSI-3 trial, the decision about thrombolysis was left to the responsible physicians. We evaluated the data on thrombolytic therapy among patients with acute myocardial infarction enrolled in the GISSI-3 trial to study the relation between rate of prescription and the characteristics of patients and participating coronary care units.

METHODS

Complete clinical data were available for 17,944 patients randomized between June 1991 and July 1993 from 200 coronary care units in Italy. Demographic and clinical information were obtained for each patient, and each coronary care unit was classified according to patient volume, level of technology, and wide geographic area in which it was located. A multivariate logistic regression was performed with administration of thrombolytic therapy as the dependent variable and previously defined clinical and structural variables as independent variables.

RESULTS

The most important factor in administration of thrombolytic therapy was that less than 6 hours elapse from symptom onset to hospital admission (odds ratio [OR] 14.05; 95% confidence interval [CI] 12.3 to 16.0). Next were location of coronary care unit in southern Italy (OR 1.81; 95% CI 1.62 to 2.01), presence of ST elevation at entrance electrocardiogram ECG (OR 1.47; 95% CI 1.35 to 1.61), absence of previous myocardial infarction (OR 1.35; 95% CI 1.22 to 1.49), and presence of catheterization laboratory or cardiac surgery program or both in the same hospital (OR 1.24; 95% CI 1.14 to 1.35). Coronary care units with high or low patient volume did not show different rates of administration of thrombolytic agents.

CONCLUSIONS

The GISSI-3 experience confirmed a high rate of prescription of thrombolytic therapy to patients admitted within 6 hours of symptom onset and those with ST-segment elevation on entrance electrocardiogram. It demonstrated that patients admitted to coronary care units with catheterization laboratories or cardiac programs or both have higher chances of receiving thrombolytic treatment than those admitted to hospitals without these capabilities.

[Female sex is not an independent risk factor in mortality during myocardial revascularization]

To assess if female sex is an independent risk factor for perioperatory mortality and morbidity, we have evaluated 971 consecutive patients (16% women) undergoing coronary artery bypass graft surgery at the Cardiovascular Disease Institution of the University of Turin from 1988 to 1990. In this study at baseline women were older and more likely to have diabetes, lower ventricular score and body surface area than men. As compared to men, women underwent surgery with delay: the surgical mortality rate and prevalence of arrhythmias were higher, and the size of the left anterior descending was smaller. At univariate analysis perioperative risk factors were as follows: age, diabetes, clinical instability, low body surface area, perioperatory infarction, postoperative infections, extracorporeal circulation time and left coronary size. At multivariate analysis only diabetes, left ventricular score, left anterior descending coronary size and emergency surgery were independent risk factors while sex, age and body surface area were not predictors of perioperatory mortality and morbidity. It is concluded that gender is not the cause of worse outcome in women.

Exhaled nitric oxide and oxygenation abnormalities in hepatic cirrhosis

Impaired arterial oxygenation, ranging from increased alveolar-arterial oxygen gradient (AaDo2) to hypoxemia, is commonly present in patients with cirrhosis. Nitric oxide (NO), through pulmonary vasodilatation, may play a major role in the oxygen abnormalities of cirrhosis. Our aim was to study the relationship between NO production and O2 abnormalities in 45 nonsmoking patients with cirrhosis and without major cardiovascular and respiratory diseases. Intrapulmonary shunting was detected by contrast-enhanced (CE) echocardiography. Lung volumes and diffusion, arterial blood gas analysis, serum NO2-/NO3-, NO output in the exhaled air, and cardiac index by the echocardiographic method were determined in all patients. Twenty-seven (60%) patients had an abnormally increased (> 15 mm Hg) AaDo2. The mean values of exhaled NO output and serum NO2-/NO3- were significantly higher in cirrhotic patients than in controls (252 +/- 117 vs. 75.2 +/- 19 nL/min/m2, P < .0001; and 47.5 +/- 29.4 vs. 32.9 +/- 10.1 micromol/L, P < .02, respectively). In all patients, there was a significant correlation between exhaled NO and AaDo2 (r = .78, P < .0001). Twelve patients (26.6%) were found to have CE-echocardiographic evidence of intrapulmonary shunting (positive CE-echo). Nine patients were considered to have hepatopulmonary syndrome (HPS) on the basis of an AaDo2 > 15 mm Hg and positive CE-echo. These 9 patients had a mean value of exhaled NO significantly higher than patients without HPS (331 +/- 73.2 vs. 223 +/- 118.4 nL/min/m2, P < .05). In all patients, cardiac index was positively correlated with exhaled NO (r = .47, P < .001) and with serum NO2-/NO3- (r = .43, P < .01). The results suggest an important role of NO in the oxygenation and circulatory abnormalities of patients with cirrhosis.

Exhaled nitric oxide and oxygenation abnormalities in hepatic cirrhosis

Impaired arterial oxygenation, ranging from increased alveolar-arterial oxygen gradient (AaDo2) to hypoxemia, is commonly present in patients with cirrhosis. Nitric oxide (NO), through pulmonary vasodilatation, may play a major role in the oxygen abnormalities of cirrhosis. Our aim was to study the relationship between NO production and O2 abnormalities in 45 nonsmoking patients with cirrhosis and without major cardiovascular and respiratory diseases. Intrapulmonary shunting was detected by contrast-enhanced (CE) echocardiography. Lung volumes and diffusion, arterial blood gas analysis, serum NO2-/NO3-, NO output in the exhaled air, and cardiac index by the echocardiographic method were determined in all patients. Twenty-seven (60%) patients had an abnormally increased (> 15 mm Hg) AaDo2. The mean values of exhaled NO output and serum NO2-/NO3- were significantly higher in cirrhotic patients than in controls (252 +/- 117 vs. 75.2 +/- 19 nL/min/m2, P < .0001; and 47.5 +/- 29.4 vs. 32.9 +/- 10.1 micromol/L, P < .02, respectively). In all patients, there was a significant correlation between exhaled NO and AaDo2 (r = .78, P < .0001). Twelve patients (26.6%) were found to have CE-echocardiographic evidence of intrapulmonary shunting (positive CE-echo). Nine patients were considered to have hepatopulmonary syndrome (HPS) on the basis of an AaDo2 > 15 mm Hg and positive CE-echo. These 9 patients had a mean value of exhaled NO significantly higher than patients without HPS (331 +/- 73.2 vs. 223 +/- 118.4 nL/min/m2, P < .05). In all patients, cardiac index was positively correlated with exhaled NO (r = .47, P < .001) and with serum NO2-/NO3- (r = .43, P < .01). The results suggest an important role of NO in the oxygenation and circulatory abnormalities of patients with cirrhosis.

Streptokinase induces intravascular release of platelet-activating factor in patients with acute myocardial infarction and stimulates its synthesis by cultured human endothelial cells

BACKGROUND

Reocclusion of a successfully recanalized infarct-related artery may account for failure of thrombolytic therapy. Evidence suggests that the intravascular activation of platelets may limit the response to this treatment. The aim of the present study was to investigate whether platelet-activating factor (PAF), an ether lipid mediator with multiple potent biological activities, is synthesized during therapy with thrombolytic agents. Two sets of experiments were performed: (1) we extracted and quantified PAF in blood of patients with acute myocardial infarction treated or untreated with streptokinase (SK), and (2) since the endothelium/platelet interaction is thought to be at the basis of vascular reocclusion, we studied whether cultured human endothelial cells synthesize PAF after stimulation with SK or plasmin.

METHODS AND RESULTS

PAF was extracted from blood samples immediately after acidification to destroy the acid-labile PAF-acetylhydrolase in 25 patients with acute myocardial infarction treated (group A, n = 14) and untreated (group B, n = 11) with intravenous infusion of SK. PAF was detected in 10 of 14 patients of group A and none of group B. PAF began to be detectable 60 to 90 minutes after SK infusion and disappeared from the circulation within 120 to 180 minutes. Percent variation of platelet count over basal values correlated negatively with the amount of PAF present in the circulation at 90 minutes (r = -.719; P < .001) and at 120 minutes (r = -.652; P < .001). Cultured human umbilical cord vein-derived endothelial cells (ECs) synthesized PAF in a dose-dependent manner in response to SK and plasmin, with a synthesis that peaked at 15 minutes and persisted up to 30 minutes for SK and 2 hours for plasmin. PAF extracted from blood samples or from ECs was quantified by bioassay performed after purification by thin-layer chromatography and high-performance liquid chromatography (HPLC). PAF-bioactive material was characterized as PAF with physicochemical and enzymatic treatments, HPLC-tandem mass spectrometry, and specific PAF-receptor antagonists.

CONCLUSIONS

The observation that PAF was detectable in the blood of patients of group A only after treatment with SK and was not detectable in patients with a comparable infarct not treated with SK (group B) suggested that SK stimulates the synthesis of this mediator either directly or via plasmin generation. Indeed, cultured human ECs synthesize PAF after stimulation with both SK and plasmin. PAF production by ECs may promote platelet activation and interaction of these cells as well as of circulating leukocytes with endothelium. These events may limit the beneficial effects of thrombolytic therapy.

Atrial natriuretic peptide and bronchial hyperresponsiveness in patients with mitral stenosis

Atrial natriuretic peptide (ANP) has been reported to have protective effects against methacholine-induced bronchoconstriction in asthmatics. The aim of the study was to evaluate the relationship between plasma ANP levels and bronchial responsiveness to methacholine in patients with mitral stenosis. In 12 patients with moderate mitral stenosis, age 35-58 years, 9 female, 8 in NYHA class 2, 4 in NYHA class 3 for symptoms, plasma ANP and bronchial threshold to methacholine (PD20FEV1) were determined. The same measurements were performed in 10 asthmatic patients, hyperresponsive to methacholine, and in 10 normal subjects, nonresponsive to methacholine. Mean +/- SE plasma ANP levels were significantly higher in patients with mitral stenosis in comparison with asthmatics and normals (159 +/- 41.8, 7.3 +/- 0.98, 7.6 +/- 1.3, respectively, p < 0.01). In patients with mitral stenosis there was a significant relationship between plasma ANP and PD20FEV1 (r = 0.81, p < 0.01). No relationship was found between ANP and PD20FEV1 in asthmatics. In conclusion, in patients with mitral stenosis ANP seems to play a protective role against bronchial hyperresponsiveness to methacholine.

Atrial natriuretic factor and concomitant hormonal, hemodynamic and renal function changes after slow continuous ultrafiltration

We treated a patient with refractory biventricular heart failure, dilutional hyponatremia and prerenal azotemia, by means of ultrafiltration. After ultrafiltration, gas exchange and cardiac output improved, with concomitant reduction of systemic and pulmonary vascular resistances. Despite a decrease of right atrial and wedge pressure, atrial natriuretic factor rose and plasma renin activity decreased.

Value of exercise stress test, radionuclide angiography and coronary angiography in predicting new coronary events in asymptomatic patients after a first episode of myocardial infarction

One-hundred-and-fifty-five consecutive symptom-free patients underwent maximal treadmill exercise testing, rest and stress radionuclide angiography at least two months after an uncomplicated acute myocardial infarction; of these, 90 underwent coronary angiography. All patients were followed-up for a mean of 32 +/- 13 months regarding the prediction of hard (death and reinfarction) and soft (angina and coronary surgery) coronary events. The specificity, sensitivity, positive and negative predictive value of exercise stress test were 47%, 76% and 41% for any coronary events; none of the patients who incurred a hard coronary event showed ischemia during electrocardiographic exercise tests. Sensitivity, specificity and positive predictive value for failure to increase the ejection fraction of at least 5% were 60%, 45% and 30% for any coronary event and 25%, 49% and 2% for any hard coronary event. The presence of multivessel disease at coronary angiography showed a sensitivity of 62% for any coronary event and of 67% for hard coronary events; specificities were 66% and 57%, and predictive values were 52% and 10%, respectively. It is concluded that electrocardiographic exercise testing, radionuclide angiography and coronary angiography are not helpful two months after an episode of uncomplicated myocardial infarction in order to identify patients who will suffer a new coronary event.

Bronchial responsiveness, oscillations of peak flow rate and symptoms in patients with mitral stenosis

To better characterize airway hyperresponsiveness reported in cardiac patients questionnaire-recorded symptoms, bronchial responsiveness to methacholine (Mch) and to ultrasonically nebulized distilled water (UNDW), diurnal oscillations of peak expiratory flow (PEF) rate were evaluated in 32 patients with moderate mitral stenosis. Twenty patients were responsive to Mch (defined as provocative dose producing a 20% fall in forced expiratory volume in one second (PD20 FEV1) less than 3.2 mg) (geometric mean PD20 FEV1 851 +/- 154 micrograms SE). Only two patients showed a fall in FEV1 greater than 20% after UNDW challenge. Patients responsive to Mch challenge had lower FEV1 as percentage of vital capacity (FEV1/VC) (80 +/- 4.8 vs 83 +/- 3.8%, p less than 0.05), higher coefficient of variation of PEF (CV-PEF) (7.1 +/- 2.8 vs 5 +/- 2.4, p less than 0.05) and higher prevalence of wheeze (70 vs 25%, p less than 0.05) in comparison with patients non-responsive to Mch challenge. CV-PEF was significantly related to FEV1 (r = 0.347, p less than 0.05) and maximal expiratory flow at 50% expired volume (MEF50) (r = 0.405, p less than 0.05). The probability of responding to Mch bronchial challenge increased proportionally with the increase in CV-PEF and the decrease in FEV1, FEV1/VC and MEF50. Airway hyperresponsiveness of patients with mitral stenosis seems to be more similar to that reported in bronchitic than in asthmatic patients.

Bronchial responsiveness, oscillations of peak flow rate and symptoms in patients with mitral stenosis

To better characterize airway hyperresponsiveness reported in cardiac patients questionnaire-recorded symptoms, bronchial responsiveness to methacholine (Mch) and to ultrasonically nebulized distilled water (UNDW), diurnal oscillations of peak expiratory flow (PEF) rate were evaluated in 32 patients with moderate mitral stenosis. Twenty patients were responsive to Mch (defined as provocative dose producing a 20% fall in forced expiratory volume in one second (PD20 FEV1) less than 3.2 mg) (geometric mean PD20 FEV1 851 +/- 154 micrograms SE). Only two patients showed a fall in FEV1 greater than 20% after UNDW challenge. Patients responsive to Mch challenge had lower FEV1 as percentage of vital capacity (FEV1/VC) (80 +/- 4.8 vs 83 +/- 3.8%, p less than 0.05), higher coefficient of variation of PEF (CV-PEF) (7.1 +/- 2.8 vs 5 +/- 2.4, p less than 0.05) and higher prevalence of wheeze (70 vs 25%, p less than 0.05) in comparison with patients non-responsive to Mch challenge. CV-PEF was significantly related to FEV1 (r = 0.347, p less than 0.05) and maximal expiratory flow at 50% expired volume (MEF50) (r = 0.405, p less than 0.05). The probability of responding to Mch bronchial challenge increased proportionally with the increase in CV-PEF and the decrease in FEV1, FEV1/VC and MEF50. Airway hyperresponsiveness of patients with mitral stenosis seems to be more similar to that reported in bronchitic than in asthmatic patients.

Intracoronary streptokinase in unstable angina: a prospective randomised study

Results of our prospective, randomised pilot trial to evaluate the clinical effects and the angiographic correlates of early thrombolysis in patients with unstable angina are reported. Sixty-seven patients had coronary angiography 10 +/- 8 (median 7) hours after an episode of transient chest pain at rest with reversible ischaemic changes on the electrocardiogram. Patients with left main disease (4), or diffuse coronary disease and unidentified ischemia-producing lesions (13) were excluded, as were those without severe (greater than or equal to 70%) stenosis (10). Intracoronary thrombus was identified at angiography in 7 patients (17%) and complex coronary lesions in 5 (12%) of the remaining 40 patients who were randomised to either intracoronary streptokinase 250,000 IU followed by intravenous heparin along with conventional treatment (20 patients), or to conventional treatment alone (20 patients). All patients received Aspirin. No differences between the streptokinase and the conventional treatment groups were observed with respect to demographic and clinical characteristics at admission to the study. During observation in the intensive care unit for 3 +/- 1 days, 8 patients (40%) with streptokinase and 10 (50%) with conventional treatment were free from angina and infarction (p = 0.75; 95% confidence interval for the difference in response rates = -20 to 40%). There were no bleeding complications and no patient died. Patients enrolled in our study had fewer coronary thrombi at angiography than currently reported. Our data did not show that adjunct treatment with streptokinase and heparin is superior to conventional treatment alone in these patients.

[The midterm clinical results of myocardial revascularization with the internal mammary artery]

After a 3-year (1985-1988) experience of myocardial revascularization using internal mammary artery (AMI) grafts and after having excluded (1986) an higher operative mortality and morbidity, clinical medium-term results have been analysed. The first 144 patients discharged alive after AMI bypass surgery in 1985 were clinically evaluated, with a mean interval of 21 months from surgery (range: 5-29 months). Exercise electrocardiographic test was performed by 100 patients, and angiography repeated in 15. Actuarial survival function was estimated by Cutler-Ederer method: 2-year actuarial survival was 99.3 +/- 0.7% (94 +/- 1.8%, when operative deaths were included). Non fatal myocardial infarction occurred in 3 patients and, at follow-up, 26 were symptomatic for angina: 2 patients underwent re-operation and 2 angioplasty. Two years after AMI bypass surgery, actuarial estimate of ischemic event-free patients was 70.9 +/- 4.5% (67.7 +/- 4.5%, when operative deaths were included): 73 out of 100 exercise tests were negative for both angina and ischemia, although only 43 patients, reached maximal work load; 9 were positive for both angina and ischemia and 18 for ischemia only. All patients who underwent angiographic evaluation (15 patients, 11 of whom because of angina relapse) had AMI grafts open, while in only 4 patients all the implanted grafts were open.

Aortocoronary bypass results: a discriminant multivariate analysis of risk factors of operative mortality

Clinical results of coronary artery bypass surgery have been evaluated analyzing operative mortality and its related risk factors. Four hundred and thirty seven consecutive patients undergoing coronary artery bypass surgery between January 1979, and December 1983, form the clinical material of this study. The gender of patients was male in 89% of the cases, the age ranged from 34 to 78 years with a mean of 54.8 +/- 8.2 (SD); patients with combined surgical procedures were excluded. The operative mortality was 5.49% (24 patients); no significant difference was found between years of the observation period. Death was due to cardiac causes in 75% of cases. Statistical analysis carried on 14 clinical, angiographic and surgical variables identified as significant risk factors of operative mortality age (p = 0.002) and cross-clamp time (p = 0.016). Both of these increased their weight when entered in a stepwise logistic regression. The EF also showed a value close to statistical significance (p = 0.06).

[Reliability of electrocardiographic criteria for the diagnosis of apical myocardial infarct]

Electrocardiographic criteria for the diagnosis of apical myocardial infarction are still debated. Aim of the present study is to evaluate if there is an electrocardiographic pattern useful in the diagnosis of apical AMI using biplane ventriculography as "gold standard" technique. For this reason, we studied 75 patients at the first AMI with a-dyskinesis in the apical zone on biplane ventriculography (segments 3 and 7 according with CASS nomenclature). By the means of ventriculography we have selected 2 groups: a first group of 19 patients with a-dyskinesis confined to apical zone and a second group of 56 patients with a-dyskinesis in the apical zone and surrounding regions. In the 2 groups we found different electrocardiographic changes. In the first group (a-dyskinesis in the apical zone only) we found the ECG pattern of anterior AMI in 14 (73.7%), antero-inferior AMI in 2 (10.5%), antero-lateral AMI in 1 (5.3%) and inferior-posterior AMI in 2 patients (10.5%), respectively; in the second group (a-dyskinesis in the apical and surrounding zones) we observed 31 (55.4%) anterior, 7 (12.5%) antero-lateral, 7 (12.5%) antero-inferior and 11 (19.6%) inferior-posterior myocardial infarctions. Our study did not allow to recognize a "typical" ECG pattern associated with the "apical" infarction seen at ventriculography.

Ultrafiltration in the treatment of refractory congestive heart failure

Artificial subtraction of fluids and solutes was evaluated in the course of acute and chronic heart failure when it became refractory to standard intensive medical treatment. A group of 19 patients (mean age 57 years), 9 with ischemic, 2 amyloidotic, 4 valvular, and 4 idiopathic cardiomyopathy, were treated. In 17 patients extracorporeal ultrafiltration (UF) by means of a polysulfonate ultrafilter was adopted along 125 sessions (105 assisted by a roller pump and 20 as a slow continuous ultrafiltrate). In two patients continuous peritoneal dialysis was adopted. In every case UF was well tolerated. Ultrafiltrate volumes ranged from 1680 to 3500 ml for every session with corresponding Na losses ranging from 194 to 434 mEq/session. Improved clinical and functional status with reduction of edema was observed in 17 of 19 patients. In 12 patients UF could be discontinued due to restored response to diuretics; 5 of these patients could subsequently undergo heart surgery (1 transplant, 3 valve replacement, 1 coronary bypass). The remaining 7 patients survived on medical therapy alone for an average of 228 days. In 7 of 19 cases, UF could not be discontinued, and these patients died after an average of 23 days of treatment. In conclusion, UF proved to be effective in eliminating salt-fluid overload and restoring response to medical treatment. Patients who are potential surgical candidates seem to be the most suitable for UF.

[Results of coronary artery bypass surgery. Surgical mortality, survival and follow-up functional state. Multivariate discriminant analysis of relative risk factors]

Clinical results of coronary artery bypass surgery, have been evaluated by analyzing operative mortality, late survival, late functional results and their related risk factors. Four hundred and thirty-seven consecutive patients who underwent coronary artery bypass surgery between January, 1979, and December, 1983, were the clinical material of this study. The gender of patients was male in 89% of the cases; age ranged from 34 to 78 years with a mean of 54.8 +/- 8.2 (SD). Patients with combined surgical procedures were excluded. Follow-up averaged 55.7 months; 404 survivors have been contacted (97% of the total study population, if operative and late deaths are added); 218 patients underwent a control exercise test; postoperative employment status was determined for 242 individuals. The operative mortality was 5.49% (24 patients). Death was due to cardiac causes in 75% of the cases. The overall actuarial survival rate was 85 +/- 1.9% after 5 years and 83.4 +/- 2.2% after 7 years. When non-cardiac related deaths were excluded the actuarial rates were 88 +/- 1.7% and 87.2 +/- 1.9% after 5 and 7 years respectively. Actuarial freedom from all ischemic events (cardiac related death, late myocardial infarction or recurrence of angina) was 66.1 after five years, and was 70.2% if operative deaths were excluded. Actuarial freedom from recurrence of angina for patients alive at follow-up was 78.7% after five years, actuarial freedom from myocardial infarction was 93.5%. The mortality hazard showed a diphasic response, being higher perioperatively and constant in the following 5 years of follow-up. All ischemic events, both singularly and together, showed an accelerated rate of occurrence at the first and after the fifth postoperative year, the slope of the curve being quite flat during the 1 to 5 year interval. The control exercise test was negative for 62.8% of the patients, positive for 33.5% and undeterminable in 3.7%. Employment status was postoperatively unaffected in 49.6% of the cases, while 27.3% of the patients retired: the remaining individuals had already retired before surgery. Statistical analysis (stepwise logistic regression) identified age (p = 0.002) and cross-clamp time (p = 0.016) as significant risk factors of operative mortality. The ejection fraction showed a value close to statistical significance (p = 0.06).(ABSTRACT TRUNCATED AT 400 WORDS)

Use of radionuclide angiography and an electrocardiographic stress test to diagnose multivessel disease after a first episode of uncomplicated myocardial infarction

Sixty consecutive patients who were symptom free 2-12 months after an uncomplicated acute myocardial infarction underwent maximal treadmill exercise testing, radionuclide angiography before and during submaximal bicycle stress test, and coronary angiography. The results of the non-invasive procedures were compared with those of coronary angiography. The sensitivity and specificity of electrocardiogram stress test for detection of multivessel disease were 40% and 77% respectively. Failure of left ventricular ejection fraction to increase at least 5% with exercise identified 20 of the 25 patients with multivessel disease (sensitivity 80%) and 23 of the 35 patients with no additional coronary artery stenosis (specificity 66%). In patients with anterior Q waves the sensitivity was 78% and the specificity 50%, whereas in the presence of inferior Q waves these values were 81% and 87% respectively. Loss of left ventricle synchronicity during effort, as indicated by failure of the standard deviation of the phases to decrease during exercise, demonstrated a radionuclide angiography sensitivity of 80% (77% for anterior myocardial infarction and 81% for inferior myocardial infarction) and a specificity of 50% (33% for anterior myocardial infarction and 64% for inferior myocardial infarction). When the test was considered to be positive if either the ejection fraction or the standard deviation of the phases criteria were positive, the sensitivity was 100% and specificity 46% (30% for anterior myocardial infarction and 65% for inferior myocardial infarction). It is concluded that in patients who are free from angina 2-12 months after an episode of uncomplicated myocardial infarction, a simple exercise electrocardiogram cannot be relied upon to detect residual ischaemia. An abnormal ejection fraction response or an increased standard deviation of the phases during exercise nuclear angiography or both identified all the patients with multivessel disease. None of the patients in whom radionuclide angiographic criteria were negative had multivessel disease.

Severe electrocardiographic abnormalities during arfonad administration

Severe and reversible electrocardiographic abnormalities (first degree atrioventricular block, left bundle branch block, ventricular fibrillation), were induced by the administration of Arfonad in a patient with type III acute aortic dissection previously chronically treated with alpha-methyl-dopa. Any other possible cause of the electrocardiographic changes was excluded on the basis of clinical findings and laboratory studies. The explanation of the electrocardiographic abnormalities induced by Arfonad are not readily apparent, also on careful review of the literature. We suggest a strict electrocardiographic monitoring during Arfonad administration especially in patients with cardiac conduction defects and previous administration of cardiac cathecholamines depleting drugs.