Prevalence of microembolic signals in patients with different types of mono-leaflet and bi-leaflet prosthetic heart valves.

Microembolic signals (MES) have been described in patients with different types of prosthetic valves. The aim of our study was to compare prevalence of MES in patients with mono-leaflet and bi-leaflet valves, and to correlate them with different clinical and echocardiographic parameters. We evaluated 42 patients, 15 with mono-leaflet and 27 with bi-leaflet valves, with 30-minute bilateral simultaneous transcranial Doppler monitoring for the identification of MES. All patients performed blood testing for international normalized ratio (INR), color-coded duplex of supra-aortic vessels, and echocardiography. Eighteen patients (43%) showed MES; 61% of MES were detected bilaterally, 17% only on the left and 22% only on the right middle cerebral artery (MCA), with no interhemispheric difference. MES did not correlate with patient's age, echocardiographic parameters, INR, presence of atrial fibrillation, or site of valve replacement. One (7%) of the 15 patients with mono-leaflet valves had MES, as opposed to 17 (63%) of the 27 with bileaflet valves (p=0.0003). Patients with bileaflet valves and MES had valves of older implantation and, only for aortic valves, larger valve size.

Normal echocardiographic characteristics of the Sorin Bicarbon bileaflet prosthetic heart valve in the mitral and aortic positions.

Doppler echocardiographic characteristics of normally functioning Sorin Bicarbon prostheses were prospectively assessed in 226 consecutive patients (135 male and 91 female patients, mean age 61 +/- 10 years) with 233 valves in the mitral (n = 67) and aortic (n = 166) positions whose function was considered normal by clinical and echocardiographic evaluation. Patterns of "normal" transprosthetic leakage were assessed with transthoracic echocardiography in all valves and with transesophageal echocardiography in six selected mitral valve prostheses. For the mitral valve prostheses, we found that peak and mean gradient, as well as pressure half-time, were not significantly different in either the 25 or the 31 mm valves (median values from 15 to 10 mm Hg, from 4 to 4 mm Hg, and from 70 to 83 ms; p = Not significant for all). On transthoracic study, 12 patients (17%) with a Sorin Bicarbon valve in the mitral position showed minimal transprosthetic leakage. On transesophageal study, all patients showed a transprosthetic leakage whose spatial distribution had a complex pattern: in planes orthogonal to the leaflet axis, two to four jets arising from the hinge points and converging toward the center of the valve plane could be visualized; in planes parallel to the leaflet axis, there were three jets, the two lateral ones diverging and the central one perpendicular to the valve plane. For the aortic valve prostheses, there was a significant decrease in transprosthetic gradients and an increase in effective orifice areas as prosthesis size increased. Peak and mean gradients decreased from a median value of 25 and 13 mm Hg in the 19 mm valves to 9 and 5 mm Hg in the 29 mm valves, respectively. Effective prosthetic valve area calculated with the continuity equation increased from a median value of 0.97 cm2 for the 19 mm size valves to 3.45 cm2 for the 29 mm size. With analysis of variance, effective prosthetic aortic valve area differentiated various valve sizes (F = 40.9, p < 0.0001) better than peak (F = 10.3, p < 0.0001) or mean (F = 8.04, p < 0.0001) gradients alone did. Furthermore, effective prosthetic aortic valve area correlated better than peak and mean gradients with prosthetic size (r = 0.76, r = -0.45, and r = -0.39, respectively). On transthoracic study, 109 patients (66%) showed minimal transprosthetic leakage. These normal values, obtained in a large number of patients with normofunctioning mitral and aortic Sorin Bicarbon valves, may help to identify Sorin Bicarbon prosthesis dysfunction.

[The methods of using the echocardiogram in outpatients. The role of the cardiologist for more appropriate use of the procedure. The Ligurian Group of the Italian Society of Cardiovascular Echocardiography]. / Modalità di utilizzazione dell'ecocardiogramma in pazienti ambulatoriali. Ruolo del cardiologo per l'appropriatezza della prescrizione. Gruppo Ligure della Società Italiana di Ecografia Cardiovascolare.

Concerns about the increasing medical care costs are causing the medical community to focus its attention on the appropriate of diagnostic tests such as echocardiography. Prerequisite to a better utilization of the limited economic resources assigned to our health care system is an analysis of how, why, and with which results diagnostic tests with a widespread use and relevant cost, like echocardiography, are requested. During the last 2 weeks of September 1994, a transversal, observational study was carried out at 13 hospital echocardiographic laboratories. Ordering physician characteristics, reasons for ordering the test, cardiological diagnostic tests previously performed and their relationship with the test results, were evaluated with a questionnaire completed by the physician who performed the test, in all the out-patients undergoing echocardiogram in that fortnight. Five hundred and sixteen consecutive questionnaires were successfully completed. Fourty-five percent of the echocardiograms were ordered by cardiologists, 35% by general practitioners, 10% by internists, and 10% by other specialists. Hypertension (16.4%) and ischemic heart disease (14.8%) were the most common indications for the test, followed by palpitations or arrhythmias (7.5%), mitral valve prolapse or mitral valve disease (7.3%), chest pain or angina pectoris (6.3%), cardiac murmur (5.5%), dyspnea or heart failure (5.2%), aortic valve disease (5%), prosthetic heart valve evaluation (4.6%), others (27%). Before undergoing the echocardiogram, 433 (84%) patients underwent an electrocardiogram, 242 (47%) a cardiological clinical evaluation, 196 (38%) a chest X-ray, and 191 (37%) had had a previous echocardiogram. The most common echocardiographic diagnosis was normal (29.2%) followed by hypertensive heart disease (16.2%), mitral valve disease (12.3%), aortic valve disease (10.5%), ischemic heart disease (9.3%), cardiomyopathy (4.9%) normal prosthetic heart valve function (4.5%), pericardial effusion (3.8%), others (11.3%). Among the echocardiograms ordered by cardiologists, 21.8% were normal in comparison with 35.4% of those ordered by general practitioners (p < 0.004), 35.3% of those ordered by internists (p = 0.04), 35.3% of those ordered by other specialists (p = 0.04). Among the 284 patients whose echocardiograms were not requested by a cardiologist, only 215 (76%) had undergone an electrocardiogram and only 68 (24%) a clinical evaluation by a cardiologist. In these patients, the frequency of normal echocardiograms was not influenced by having undergone a previous electrocardiogram or a chest X-ray. Conversely, patients in whom the echocardiogram was ordered after a cardiology consult showed a significant lower frequency of normal results compared to patients not evaluated by a cardiologist (23% vs 39%; p < 0.05). More than 50% of the echocardiograms performed in out-patients are ordered by physicians who are not cardiologists. Among these echocardiograms, about 1 out of 3 results normal. This finding suggests an improper use of echocardiogram as a screening tool by non-cardiologists in out-patients. A preceding clinical evaluation by a cardiologist, but not an electrocardiogram or a chest X-ray alone, may determine a more appropriate use of the test being associated with a reduced frequency of normal results.

[Systemic fibrinolysis in patients with refractory unstable angina]. / Fibrinolisi sistemica in pazienti con angina instabile refrattaria.

We tested the safety and the usefulness of intravenous fibrinolysis in 44 patients with refractory unstable angina, defined as persistence of ischemic episodes during 48-hour Holter monitoring (phase 1) despite maximal medical therapy. After fibrinolysis, recurrence of ischemia was recorded during 1 week of observation in CCU including 2 24-hour Holter monitoring at the beginning and at the end of this week (phase 2): 17 patients completed the observation period without either symptomatic or asymptomatic ischemic episodes (Group A); the remaining 27 patients continued to manifest ischemia (Group B). No bleeding complications occurred. Within a 6-month follow-up, 2 patients of Group A had recurrence of unstable angina while in Group B, 10 patients underwent CABG or PTCA for refractory angina, 6 other patients with refractory angina continued medical therapy, 1 patient had a myocardial infarction and 2 patients died (p less than 0.001). Phase 1: the duration of total ischemia (min/24 hours) was a relevant prognostic marker: higher duration correlated with adverse clinical outcome (p less than 0.01). Phase 2: in comparison with phase 1, duration of total ischemia was significantly reduced (p less than 0.001). A percent value expressing this variation was calculated for each patient: (min of ischemia in phase 2 - min of ischemia in phase 1/min of ischemia in phase 1). The variation thus obtained again gave information on the clinical outcome: the greater was the reduction, the lower was the risk of cardiac events (p less than 0.001). Our data suggest that: clinical stabilization may be obtained with the addition of fibrinolysis to conventional treatment; Holter monitoring bears prognostic information helpful in identifying patients who need further intervention.

Intravenous nifedipine prevents ergonovine-induced myocardial ischemia in patients with stable effort angina.

Twelve of 40 consecutive patients with effort angina, documented coronary artery disease, and a positive exercise stress test had a positive ergonovine test. ST-segment depression (0.1 mV) occurred in ten and ST elevation (0.1 mV) in two patients. During the ergonovine maleate test the rate-pressure product recorded at the onset of ischemia (ST greater than or equal to 0.1 mV) was significantly lower than that recorded during the exercise stress test. The reproducibility of the rate-pressure product at ischemia was displayed in every patient with a second test; then, a third test after intravenous nifedipine infusion (1 mg over 5 minutes + 1 mg over 55 minutes) was performed. Six patients had negative results; out of the remaining six, three exhibited a significant increase in the dosage required for provoking ischemia. Both systolic and diastolic blood pressure were reduced by nifedipine, while only a slight increase in heart rate occurred, so that the rate-pressure product at any ergonovine dosage was decreased by nifedipine. No differences in the ischemic threshold during exercise and during the ergonovine maleate tests (in washout and after nifedipine) were found in patients with a positive or negative response to nifedipine. The ergonovine test was positive in a sizable (30%) number of patients with stable effort angina. In these patients nifedipine was effective in preventing ergonovine-induced myocardial ischemia.