Influence of clinical presentation on the outcome of acute B aortic dissection: evidences from IRAD

AIM

In-hospital outcome of acute type B dissection (ABAD) is strongly related to preoperative aortic conditions. In order to clarify the influence of the clinical presentation on the outcome, we analyzed the patients of the International Registry of Acute Aortic Dissection (IRAD). All patients affected by complicated ABAD, enrolled in the IRAD from 1996-2004, were included. Complications were defined as the presence of shock, periaortic hematoma, spinal cord ischemia, preoperative mesenteric ischemia/infarction, acute renal failure, limb ischemia, recurrent pain, refractory pain or refractory hypertension (group I). All other patients were categorized as uncomplicated (group II). A comprehensive analysis was performed of all clinical variables in relation to in-hospital outcome.

RESULTS

The overall in-hospital mortality among 550 patients was 12.4%. Mortality in group I (250 patients) was 20.0 %, compared to 6.1% in group II (300 patients) (P<0.001). Univariate predictors of ABAD complications were Marfan syndrome, abrupt onset of pain, migrating pain, any focal neurological deficits, need for higher number of diagnostic examinations and use of magnetic resonance and/or aortogram, abdominal vessels involvement at aortogram, larger descending aortic diameter, especially >6 cm, pleural effusion, and widened mediastinum on chest X-ray. Univariate predictors of a non complicated status were normal chest X-ray and medical management. In group I, in-hospital mortality following surgical and endovascular intervention were 28.6% and 10.1% (P=0.006), respectively. Independent predictors of overall in-hospital mortality included age >70 years, female gender, ECG showing ischemia, preoperative acute renal failure, preoperative limb ischemia, periaortic hematoma, and surgical management. The only independent variable protective for mortality was magnetic resonance as diagnostic test.

CONCLUSION

ABAD is a heterogeneous disease that produces dissimilar clinical subsets, each of which can have specific clinical signs, management and in-hospital results. In IRAD ABAD uncomplicated patients, medical therapy was associated with best hospital outcome, while endovascular interventions were associated with better results than surgery when invasive treatments were required. Although selection bias may be possible, and irrespective of treatments, knowledge of significant risk factors for mortality may contribute to a better management and a more defined risk-assessment in patients affected by ABAD.

Serum antibody response to Cryptococcus neoformans in cats, dogs and koalas with and without active infection

Anti-cryptococcal antibodies were measured in normal cats, dogs, horses and koalas, and cats, dogs and koalas with cryptococcosis using an enzyme immunoassay. Antibody levels were expressed as absorbance readings. Over 80% of cats and dogs with cryptococcal infection had elevated antibody levels at the time of diagnosis, during or after successful therapy. Antibody levels in these patients either remained elevated or declined slowly after treatment. For cats, anti-cryptococcal antibody levels were higher in C. neoformans var. gattii than var. neoformans infections, and lower in mild than in moderate or severe infections. The persistence of increased anti-cryptococcal antibody levels in over half of the feline and canine cases following active infection suggested the use of antibody determinations as a seroepidemiologic marker of previous infection. Consequently, antibody measurements from 'normal' animals indicated a prevalence of previous cryptococcal infection of 10% in cats and dogs, compared with 3% in horses and 5% in koalas. Preliminary studies of young animals suggested that anti-cryptococcal antibody levels were substantially lower in the young cats but not the young dogs surveyed, compared with their mature counterparts. The cut-offs used in the present work may thus be erroneously high, with a corresponding underestimation of the prevalence of inapparent cryptococcosis.

Serum antibody response to active infection with Cryptococcus neoformans and its varieties in immunocompetent subjects

Using a class-specific enzyme immunoassay IgG and IgA anticryptococcal antibody was measured in 400 serum specimens at 1 week to 11.7 years after diagnosis from 43 immunocompetent subjects with confirmed active cryptococcosis. The prevalence of IgG was 86% at diagnosis, rose to 100% by 2 weeks and remained high thereafter. IgA prevalence was 71% at diagnosis, rose to 75% at 2 weeks and then fell over 2 years. IgG and IgA prevalence in paediatric controls was 5% and 0%, respectively. Mean antibody levels showed the same pattern and neither levels nor prevalence were influenced by age, sex or site of infection. Patients with the variety gattii infection had a greater antibody response than those with the variety neoformans which was significant for IgA. Specific anticryptococcal antibody was regularly present in conjunction with cryptococcal antigen at diagnosis. IgG persists but IgA falls over 1-2 years. The assay described may be a useful tool to study the antibody response and seroepidemiology of infection with C. neoformans.