Effects of age and coronary artery disease on cerebrovascular reactivity to carbon dioxide in humans.

Alterations in cerebrovascular reactivity to CO2, an index of cerebrovascular function, have been associated with increased risk of stroke. We hypothesised that cerebrovascular reactivity is impaired with increasing age and in patients with symptomatic coronary artery disease (CAD). Cerebrovascular and cardiovascular reactivity to CO2 was assessed at rest and during hypercapnia (5% CO2) and hypocapnia (hyperventilation) in subjects with symptomatic CAD (n=13) and age-matched old (n=9) and young (n=20) controls without CAD. Independent of CAD, reductions in middle cerebral artery blood velocity (transcranial Doppler) and cerebral oxygenation (near-infrared spectroscopy) were correlated with increasing age (r = -0.68, r = -0.51, respectively, P < 0.01). In CAD patients, at rest and during hypercapnia, cerebral oxygenation was lower (P < 0.05 vs. young). Although middle cerebral artery blood velocity reactivity was unaltered in the hypercapnic range, middle cerebral artery blood velocity reactivity to hypocapnia was elevated in the CAD and age-matched controls (P < 0.01 vs. young), and was associated with age (r = 0.62, P < 0.01). Transient drops in arterial PCO2 occur in a range of physiological and pathophysiological situations, therefore, the elevated middle cerebral artery blood velocity reactivity to hypocapnia combined with reductions in middle cerebral artery blood velocity may be important mechanisms underlying neurological risk with aging. In CAD patients, additional reductions in cerebral oxygenation may place them at additional risk of cerebral ischaemia.

Pulmonary artery sarcoma mimicking pulmonary embolism.

Two cases of primary pulmonary sarcoma which were initially diagnosed as pulmonary thromboembolism are presented. The clinical and radiologic features of pulmonary sarcoma are reviewed, with special emphasis on the features which distinguish it from thromboembolism.

Relative risks of left ventricular aneurysmectomy in patients with akinetic scars versus true dyskinetic aneurysms.

From 1971 to 1988, 303 patients underwent left ventricular aneurysm resection. We analyzed preoperative and procedure-related variables to ascertain risk factors for surgery. A distinction was made between akinetic and dyskinetic aneurysms to assess potential relation with postoperative outcome. Indications for surgery were arrhythmia in 20 patients, congestive heart failure in 81, angina in 133, congestive heart failure and angina in 42, and other combinations in the remaining 27 patients. The left ventricular aneurysm was dyskinetic in 180 patients and akinetic in 121. Risk factors and surgical procedures were similar in both groups. Left ventricular ejection fraction was less than or equal to 30% in 98 patients. Coronary bypass grafting was performed in 269 patients, with an average of 2.3 grafts per patient. Mitral valve replacement, the most common concomitant procedure, was performed in 16 patients. Intra-aortic balloon assist was required postoperatively in 47 patients. Overall operative mortality was 13% (38 patients) and was due to low cardiac output in 23 patients and arrhythmia in 12 patients. Univariate and multivariate analyses related early mortality to New York Heart Association functional classification of heart failure, the predominant indications of arrhythmia or congestive heart failure, left ventricular ejection fraction less than or equal to 30%, the need for intra-aortic balloon support, and the excision of an akinetic (18%) rather than dyskinetic (8%) left ventricular aneurysm. Over a follow-up period averaging nearly 5 years, the actuarial survival at 5 years was 63% in the dyskinetic group and 51% in the akinetic group.(ABSTRACT TRUNCATED AT 250 WORDS)

Pericardial closure after cardiac operations. An animal study to assess currently available materials with particular reference to their suitability for use after coronary artery bypass grafting.

An experimental study to assess the performance of currently available pericardial substitutes is described with particular reference to their use after coronary artery bypass grafting. Seventy-two ewes, (six groups of 12 animals) had a 7 x 5 cm portion of the pericardium excised. Each group had either the defect left open, primarily resutured, replaced with coarse Dexon No. 2 mesh (American Cyanamid Co., Danbury, Conn.), replaced with fine Dexon No. 8 mesh, replaced with glutaraldehyde-preserved bovine pericardium, or replaced with polytetrafluoroethylene 0.1 mm surgical membrane. Six animals from each group were assessed at 3 months and the remaining six animals were assessed at 6 months. The open-defect and resutured groups served as control animals. None of the substitutes proved superior to the open-defect group in the prevention of chest wall/lung-to-pericardium adhesions at either 3 or 6 months. The limitations of the animal model in assessing this aspect of substitute performance are discussed. Whereas the bovine pericardium, polytetrafluorethylene, and Dexon No. 8 mesh groups were superior to the resutured group in the prevention of pericardium-to-epithelium adhesions in the area of the patch, this advantage was lost at 6 months when resuturing proved as effective as polytetrafluoroethylene and bovine pericardium. In all groups there was little tendency to produce generalized pericardial adhesions. At 3 months Dexon No. 8 mesh and bovine pericardium produced the least amount of significant epicardial reaction. In two animals in the 3-month polytetrafluoroethylene group and in one animal in the 6-month polytetrafluoroethylene group, a "fibrous peel" was encountered on the inner surface of the patch, which had also become adherent to the epicardium and had obscured the underlying anatomy. At 6 months the open-defect, resutured, and bovine pericardium groups had produced no significant epicardial reaction. In one animal at 6 months the bovine pericardium had become markedly thickened and degenerative. We do not recommend routine closure of the pericardium after coronary artery operations with any of the substitutes investigated in our study.

Correction of interrupted aortic arch.

Twelve consecutive infants with interrupted aortic arch, ventricular septal defect, and persistent ductus arteriosus have had the anomaly repaired without the use of synthetic grafts. In two infants (5 and 9 months) the ductus arteriosus was used for the arch repair. In three patients (mean age 14 days) the left carotid artery was turned down to form the new arch. In the remaining seven (mean age 12 days) a direct anastomosis was achieved, but one of these patients died at operation. Two others in this group also had persistent truncus arteriosus. Five patients have required another operation (two for stenosis of the anastomosis with one death). The 10 survivors (mean follow-up 5 years) are well and support our belief that complete repair without the use of synthetic grafts is the treatment of choice in this rare and difficult group.

Value of serum magnesium estimation in diagnosing myocardial infarction and predicting dysrhythmias after coronary artery bypass grafting.

Serial serum magnesium estimations, beginning before operation, were performed on 200 patients who underwent coronary artery bypass grafting. The results indicate that serum magnesium concentration is of no value in the diagnosis of myocardial infarction in the postoperative patient or in predicting which patients are susceptible to postoperative dysrhythmias. There was no statistically significant difference in serum magnesium values between those patients who had an uncomplicated course and patients who had sustained either myocardial infarction or postoperative dysrhythmia or both.

Heterograft valve replacement experience.

Survey of implantation of porcine heterograft valves in the Dunedin Cardiac Surgical Unit has been reviewed covering 140 patients and 166 valves with a follow-up ranging from 1-55 months. The low mortality, minimal complication rate and absence of long term anticoagulants in the post operative regime are emphasized. Discussion centres on the low rate of complications and the usefulness of this valve. As with all biological valves durability is still in question.

Reintroduction of anti-inflammatory drug therapy after drug-associated gastro-intestinal disturbances.

The relative risks associated with anti-inflammatory drug prescription for patients with an earlier history of drug-associated gastro-intestinal disturbance have been investigated in a retrospective study. Under these circumstances ibuprofen was well tolerated. The risks associated with modified salicylates (principally aspirin in enteric-coated form) and indomethacin suppositories also appeared to be relatively slight. Retreatment with phenylbutazone, oral indomethacin, naproxen and combination therapy was hazardous.

Pleural fibromas: a clinical review and report of six patients.

Localized pleural fibromas are a definite clinical entity. Their origin is much debated. Though most arise from the mesothelial cell, occasionally some arise from the pleural fibroblast. The former retain the potential to become malignant. Distinguishing between the two origins can aid prognosis after treatment. The characteristic cell is a spindle-shaped fibroblast. Slits or clefts lined by flattened cells are often present in the tumor. Clinically, pleural fibromas are usually asymptomatic, space-occupying lesions. Chest symptoms are nonspecific. Extrathoracic symptoms, especially arthritis, are not uncommon and occur only in the benign variety. Excision is the treatment of choice, but long-term follow-up is essential, for recurrence is not unknown and is often heralded by the region of arthritic symptoms. Recurrences may be benign or malignant, the latter having a poor prognosis, with most patients dying within 2 years. Experience with benign pleural fibromas seen in 6 patients over a 25-year period is presented.

Lateral subluxation of the atlas in rheumatoid arthritis.

Two patients with lateral subluxation of the atlas resulting from rheumatoid disease involving the upper cervical spine have been described. The deformity can be suspected on clinical grounds and in one of our two patients spinal cord damage was a sequel. Erosion of the opposing surfaces of the odontoid and lateral masses of the atlas with detachment of the transverse ligament and deeper fibres of the posterior longitudinal ligament appear to underlie this deformity. Radiological confirmation may require AP views with the head tilted to one or other side.