A comparative clinical assessment of a hollow-fibre membrane oxygenator (Capiox II) and a bubble oxygenator (Harvey 1500).

Personal experience is reported on the use of a membrane oxygenator, the Capiox II, which is clinically compared with a bubble oxygenator for medium-term perfusion. The characteristics considered were the efficiency of the heat exchanger, the oxygenating capacity, traumatic effects on the blood and the direct effect on the renal and cardiopulmonary systems. The Capiox II demonstrated a better oxygenating capacity, less platelet damage, a smaller variation in the free plasma haemoglobin, a significant difference in postoperative bleeding and blood transfusion requirements, but showed no variation in renal and cardiopulmonary function. The authors suggest that the Capiox II is to be preferred for extra-corporeal circulation of medium duration, for which it combines the advantages of both bubble and membrane oxygenators, while being less complex and costly than previously marketed membrane devices.

Valve replacement with the tilting disc Sorin prosthesis in patients with narrow aortic annulus.

The Authors summarize their 5-year experience of the clinical use of the Sorin tilting disc prosthesis in 40 patients (group A) with narrow aortic annulus, compared with a control group (group B: 116 patients) where a larger Sorin prosthesis was implanted. Follow-up lasted from 1 to 60 months, with a mean of 25.6 +/- 12.3 in group A and 20.4 +/- 11.9 in group B. Early and late mortality were low: 1/40 and 2/39 (2.5 and 5.1%) in group A and 4/116 and 9/112 (3.4 and 8.0%) in group B (p = NS): only two deaths, one in each group, were prosthesis-related. Actuarial survival was comparable: 91.2% (CL: 96.3-86.1%) in group A and 78.0% (CL: 87.6-68.4%) in group B, as were probability of being event-free and alive, non-reoperated and with few or no symptoms [group A: 61.7% (CL: 72.4-51.0%) and 77.4% (CL: 85.9-68.9%) respectively; group B: 78.8% (CL: 83.4-74.2%) and 61.1% (CL: 85.9-68.9%) respectively]. The Authors conclude that the Sorin tilting disc prosthesis is a reliable valve substitute in the narrow aortic annulus; they recommend that enlargement procedures should be confined only to patients with annulus size less than 19 mm.

The value of segmental pressure measurement in the assessment of peripheral vascular disease.

In 60 patients with symptomatic peripheral vascular disease a study was performed to evaluate the reliability of segmental pressure measurement in detecting and localizing vascular lesions. Five groups of limbs with different pressure patterns were identified: normals, distals disease (diabetics), aorto-iliac disease, aorto-iliac and superficial femoral disease, superficial femoral and distal disease. The comparison with angiography showed the high efficacy of this method (when combined with Doppler study of the arteries) to localize and quantify the lesions. The combination with femoral intraarterial pressure measurement allows to predict exactly the segmental pressure after segmental vascular reconstructions. It is concluded that segmental pressure measurement (with the described technique) selects patients for angiography and surgery and can predict the outcome of vascular reconstruction.

[Mitral valve substitution, using the Lillehei-Kaster prosthesis]. / La sostituzione valvolare mitralica con la protesi di Lillehei-Kaster.

Personal experience acquired in the course of 177 mitral valve replacements with a Lillehei-Kaster prosthesis up to June 1977 is discussed. Intraoperative mortality was 8.5%. Postoperative mortality (as at 31-12-1976) was 5.3%. The clinical, radiological, and ergometric findings were fully satisfactory. Haemodynamic examination at rest and during effort revealed improved pressure and heart capacity values. The mean transprosthetic gradient at rest was 5.61 and rose to 13.53 (after uncalibrated effort). Thromboembolism was noted in 5 patients (3.1%), as in the literature. The haemodynamic features and low thrombogenicity of the Lillehei-Kaster prosthesis would thus appear to make it a sound replacement for the mitral valve.

[Aortic valve replacement in a case of Takayasu's disease with polydistributed localization]. / Sostituzione valvolare aortica in un caso di malattia di Takayasu a localizzazione polidistrettuale.

We report a case of a 49 year-old woman suffering from severe aortic regurgitation due to Takayasu's disease involving the ascending and abdominal aorta and the brachial arteries. The patient was managed successfully with aortic valve replacement. Considering the Literature data, the pathogenesis of the aortic insufficiency and the main surgical and anaesthesiologic problems related to the Takayasu's disease are discussed.

[Reversibility of left ventricular functional damage after valve replacement in patients with chronic aortic valve insufficiency]. / Reversibilità del danno funzionale del ventricolo sinistro dopo sostituzione valvolare in pazienti affetti da insufficienza valvolare aortica cronica.

The authors study retrospectively some preoperative echocardiographic findings and their importance as predictors of reversible myocardial dysfunction. The functional status of 57 survivors after isolated aortic valve replacement was evaluated with exercise testing and on this ground the patients, were divided into three groups: A (28 pts) greater than 60%; C (10 pts) less than 40%; B (19 pts) from 40% to 60%. The authors conclude that the postoperative improvement in functional status is strictly correlated with some preoperative echocardiographic indexes (end-diastolic dimension, end-systolic dimension, shortening fraction, mean end-systolic radius/thickness ratio, end-systolic wall stress, myocardial mass, ejection fraction) with are also predictive of operative mortality. The authors consider the principal values of beginning left ventricular impairment: a) end-systolic dimension greater than or equal to 5.5 cm; b) shortening fraction less than 27%; c) mean end-systolic radius/thickness ratio greater than 2.5; d) end-systolic wall stress greater than 240 mmHg.

Hemodynamics of critical arterial stenoses.

The mechanics and the physiological problems related to critical arterial stenosis have been investigated by mathematical, biological and clinical models in experimental and clinical conditions. The value of critical stenosis has been defined in many ways but all the previous report on this subject agree in defining critical stenosis a reduction in section of the artery that can alter the poststenotic flow and pressure. Experimentally appreciable changes in pressures and flow do not occur until the cross-sectional area of a vessel has been reduced by more than 75% and these data are comparable to clinical situations. The data of several reports on this subject are plotted and compared and the different experiences are analysed to evaluate the best criteria to define the critical value of one stenosis and the clinical utilizations.

Arterial pressure measurements correlated to symptoms and signs of peripheral arterial disease.

The systolic pressure observed in 150 patients with peripheral arterial disease has been compared to their symptoms and signs. In patients with claudication the ankle mean pressure was 58 mmHg. In patients with rest pain it was 33 mmHg and in patients with chronic ulcerations it was 20 mmHg. In these 3 groups the mean ankle-foot pressure gradient was low (2-10 mmHg) were detected at the level of the iliaco-femoral and femora-popliteal segments. In the group of diabetic patients an high gradient was observed. Patients with peripheral arterial disease can be divided in four symptomatic groups but the angiographic and physiological patterns of patients with rest pain and ischemic ulcerations are similar and they are the best candidates to reconstructive arterial surgery.

[Classification of congenital aortic stenosis]. / Classificazione delle stenosi aortiche congenite

Recent epidemiological data relating congenital stenosis of the aorta are cited. An anatomical criterion is used in the formation of three classification groups, each containing a number of different types. There are no clear-cut clinical pictures corresponding to these anatomical varieties, however, so that differential diagnosis is dependent on the haemodynamic and contrastographic data. There are, on the other hand, clinical signs that serve as pointers to the site of the stenosis.

[Problems in emergency surgery. Massive pulmonary embolism. Clinical and diagnostic aspects]. / Problemi in chirurgia d'urgenza. L'embolia polmonare massiva. Aspetti clinici e diagnostici.

In spite of the many advances in diagnosis, pulmonary embolism is still hard to identify, one problem stemming from the similarity of its clinical signs with heart and lung conditions. The present study was carried out on 17 patients affected by massive pulmonary embolism. Clinical aspects and diagnostic problems are discussed, with particular regard to the data supplied by chest X-ray, catheterism of the right cardiac cavities and angiopneumographic investigation.

[Major complications of median sternotomy]. / Le complicanze maggiori della sternotomia mediana.

After examining the modalities of sternal perfusion and the techniques of median sternotomy, with special regard to closure techniques, personal experience of 1000 sternotomies is reviewed. Complications may be major or minor, incidence was 1,8% and total mortality two cases. After reviewing the various causes of sternal dehiscence, reported and personal experience of the various techniques for preventing and treating the complication is discussed.