Revisiting Fisher: range size drives the correlation between variability and abundance of British bird eggs

We evaluate the correlation between intraspecific variation in egg size and population size in breeding British birds. Using information on abundance, range occupancy, migration status and phylogenetic relationships among species, we show that a wider geographical distribution rather than larger population size per se best predicts egg size variability. A similar result applies to wing length variability. Results from a phylogenetic path analysis suggest that geographical variation is the most parsimonious causal explanation for high intraspecific variation in common species.

[An aortobronchial fistula 11 years after the resection of a posttraumatic aortic aneurysm]

A case of a 47-year-old white male who developed an aortobronchial fistula eleven years after resection of a posttraumatic aneurysm of the descending aorta is presented. The clinical picture, the diagnostic problems as well as the treatment are presented and commented.

The Monostrut Björk-Shiley valve. Seven years' experience

The results of cardiac valve replacement with the Monostrut Björk-Shiley prosthesis (Shiley, Inc., Irvine, Calif.) during a 7-year period are presented. A total of 984 valves were implanted in 820 patients from May 1983 to April 1990. Aortic valve replacement was performed in 378 patients, mitral replacement in 294, and multiple replacement in 148. In addition, 180 patients (22%) underwent associated procedures. Mean age was 52.6 +/- 11 years. Operative (30 days) mortality was 5.9% (49 patients): 3.9% (15 patients) for aortic, 7.8% (23 patients) for mitral, and 7.4% (11 patients) for multiple valve replacement. All patients were given long-term anticoagulation therapy. Follow-up was 99% complete (eight patients were lost to follow-up), with a closing interval of 3 months, and totaled 2422 patient-years. Valve-related complications, expressed as percentage event-free (+/- standard error) at seven years were as follows: structural deterioration, 100%; nonstructural dysfunction, 98.3% +/- 0.6%; thromboembolism, 90.2% +/- 1.7%; anticoagulant-related hemorrhage, 88.7% +/- 2.8%; and prosthetic valve endocarditis, 98.1% +/- 0.8%. There were no cases of valve thrombosis. Actuarial survival (free from operative, valve-related, and sudden death) was 88.4% +/- 1.2% at 7 years. Freedom from reoperation was 96.8% +/- 0.1%. Probability of being free from all valve-related morbidity and mortality was 70% +/- 3%, and 708 (93%) of the survivors were in New York Heart Association class I or II. Serial Doppler echocardiograms were done prospectively in 243 patients (with 154 aortic and 120 mitral prostheses), both postoperatively and at regular intervals up to 3 years. Mean prosthetic gradients ranged from an average of 20.9 to 7 mm Hg in the aortic prostheses (21 to 29 mm) and from 6.1 to 4.8 mm Hg in the mitral prostheses (25 to 31 mm). The gradients in each patient did not change significantly during the follow-up period. Our 7 year's experience with the Monostrut valve shows a low rate of valve-related complications, a durable design, and good hemodynamic and functional results.

[The long-term results of aortocoronary bypass surgery in patients with a severe preoperative left ventricular dysfunction]

We analyze retrospectively the short- and long-term results of coronary artery bypass surgery in 50 patients with severe left ventricular dysfunction operated in a period of 11 years. Sixty-six percent of patients had unstable angina and 12% of total presented angina post-acute postmyocardial infarction. Thirty-eight percent of patients were in preoperative functional class III-IV of NYHA. Three-vessel disease was present in 70% of the patients, two-vessel in 30%, and the main trunk was affected in 12% of the global. Hospital mortality was 4% (2/50) due to low cardiac output syndrome. Follow-up was available in all the survivors and ranged 6 months-11 years (mean: 4.8 +/- 3.1). During follow-up, 13 patients died, but in only six was due to cardiac cause. The 35 patients followed were in functional class I-II of NYHA. Eighty-eight percent of the patients were angina free at follow-up. Actuarial analysis, after exclusion of 3 patients who died of causes no directly related to the heart, showed an intrahospital survival rates of 96%; at first year was 92, at 3rd was 78%, and 5th year survival rates were 75%. In conclusion, patients with symptomatic angina and preoperative severe left ventricular dysfunction, coronary artery bypass graft has a low hospital mortality, is effective in improving angina and heart failure, and the long-term survival is acceptable.